JP2007238958A - Foam of urethane-based thermoplastic elastomer composition and process for producing the foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam excellent in permanent elongation, hysteresis, cell uniformity, and heat resistance; a method for producing the foam; and a molded article and a laminated article obtained from the foam. <P>SOLUTION: The method of the present invention for producing a urethane-based thermoplastic elastomer composition foam comprises the steps of: adding and mixing 0.1 to 30 parts by weight of carbon dioxide (B) to 100 parts by weight of a urethane-based thermoplastic elastomer composition (A) in a molten state, in which the urethane-based thermoplastic elastomer composition comprises a urethane-based thermoplastic elastomer (A-1) and other thermoplastic elastomer (A-2) in an (A-1)/(A-2) ratio of 20/80 to 99/1 by weight, to form a molten urethane-based thermoplastic elastomer composition (C) (gas dissolving step); and lowering a temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step). The present invention can be used for producing the urethane-based thermoplastic elastomer foam of stable quality over a range from a low foamed product to a highly foamed product. A foam excellent in flexibility, thermal insulation and surface appearance can be also produced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a urethane-based thermoplastic elastomer composition foam, a method for producing the same, and a molded product or a laminate comprising the foam. More specifically, a urethane-based thermoplastic having a constant foam quality obtained by using a specific urethane-based thermoplastic elastomer and, if necessary, another thermoplastic elastomer and carbon dioxide as a foaming agent. The present invention relates to an elastomer composition foam, a method for producing the same, and a molded product or a laminate comprising the foam.

  Conventionally, foams made of polyurethane, polyvinyl chloride or the like have been used as foams having excellent flexibility and buffering properties. In addition, foams made of polystyrene, polyethylene, polypropylene, and the like have been used as foams having excellent thermoformability.

  A method for producing a polyethylene foam is disclosed, for example, in Japanese Patent Publication No. 41-6278 (Patent Document 1). The foam produced by this method is excellent in thermoformability such as vacuum molding, but is flexible. There was a problem of not exhibiting buffering characteristics.

  As a method for producing a thermoplastic polyurethane foam, chemical foaming using a thermally decomposable foaming agent such as azodicarbonamide disclosed in JP-A-7-157588 (Patent Document 2) is known. In chemical foaming, part of the thermoplastic polyurethane decomposes and foams, so that cell roughening is likely to occur and it is difficult to produce a high molecular weight foam.

For this reason, the appearance of a foam excellent in all of permanent elongation, hysteresis, cell uniformity, and heat resistance has been desired. In addition, there has been a demand for the simple production method of such foams and the appearance of molded bodies, laminates and the like using them.
Japanese Patent Publication No.41-6278 JP 7-157588 A

  The present invention includes foams excellent in permanent elongation, hysteresis, cell uniformity, and heat resistance, and in particular, compositions containing thermoplastic polyurethane (including 100% thermoplastic polyurethane resin. As long as the thermoplastic polyurethane composition means this composition), a method for producing the foam, and a molded product and a laminate obtained from the foam. .

  The present invention also provides a method for easily foaming a thermoplastic polyurethane composition.

  The present inventors have intensively studied to solve the above problems, and have found a foam obtained from a thermoplastic polyurethane composition excellent in permanent elongation, hysteris, cell uniformity, and heat resistance. In addition, a urethane-based thermoplastic elastomer composition in which a specific urethane-based thermoplastic elastomer and other thermoplastic elastomers are blended in an arbitrary composition ratio, and foamed with carbon dioxide as a foaming agent, foams with various expansion ratios It was found that a thermoplastic polyurethane foam can be easily obtained.

  That is, the present invention is as follows.

The urethane-based thermoplastic elastomer composition foam according to the present invention is a foam composed of a thermoplastic polyurethane resin-containing composition containing 20% by mass or more of a thermoplastic polyurethane resin, and the average cell diameter of the foam is 0. .1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³ ,
Permanent elongation is 1% or more and 100% or less,
The bulk density is 0.03 or more and 1.10 g / cm ³ or less.

The melting point (T _m1 ) of the urethane-based thermoplastic elastomer composition foam and the melting point (T _m2 ) of the _unfoamed body are expressed by the following formula (1).
T _m1 -T _m2 ≧ 5 ℃ (1)
It is preferable to satisfy.

  It is preferable that 10 mass% or more of chloroform insoluble content is contained in the said urethane type thermoplastic elastomer composition foam.

The urethane-based thermoplastic elastomer composition foam has a residue after extraction with chloroform of 20% by mass or more,
The 5% weight reduction temperature of the residue after extraction with chloroform is preferably 180 ° C. or higher.

The 1st manufacturing method of the urethane type thermoplastic elastomer composition foam which concerns on this invention consists of a urethane type thermoplastic elastomer (A-1) and another thermoplastic elastomer (A-2), (A-1) And the urethane-based thermoplastic elastomer composition (A) in a molten state in which the mass ratio (A-1 / A-2) of (A-2) is 20/80 to 99/1, and the urethane-based thermoplastic elastomer composition 0.1 to 30 parts by mass of carbon dioxide (B) is added to and mixed with 100 parts by mass of product (A), and the urethane thermoplastic elastomer composition (A) and carbon dioxide (B) are mixed. Forming a molten urethane-based thermoplastic elastomer composition (C) (gas dissolving step);
And a step of reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step).

Moreover, the 2nd manufacturing method of the urethane type thermoplastic elastomer composition foam which concerns on this invention is 0 to 100 mass parts of this urethane type thermoplastic elastomer composition (A) to a thermoplastic polyurethane resin of a molten state. 0.1 to 30 parts by mass of carbon dioxide (B) is added and mixed, and a molten urethane-based thermoplastic elastomer composition (C) in a mixed state of the urethane-based thermoplastic elastomer composition (A) and carbon dioxide (B). ) Forming process (gas dissolution process);
Next, the molten urethane-based thermoplastic elastomer composition (C) obtained through the step of reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step) is reduced to a pressure lower than that of the cooling step. Filling or transferring into a controlled space, generating cell nuclei in the molten urethane-based thermoplastic elastomer composition (C), and then foaming while controlling the expansion ratio (foaming control step). It is characterized by.

  The urethane thermoplastic elastomer composition (A) preferably has a melt flow rate (ASTMD-1238-65T) of 0.5 to 50 g / 10 min.

The urethane thermoplastic elastomer composition (A) is a urethane thermoplastic elastomer (A-1) and a melt flow rate (ASTMD-1238-65T) of 0.01 g / 10 min or more and less than 50 g / 10 min. It consists of some other thermoplastic elastomer (A-2),
It is preferable that 5-100 mass parts of said other thermoplastic elastomers (A-2) are contained with respect to 100 mass parts of said urethane type thermoplastic elastomer compositions (A).

  The temperature of the molten urethane-based thermoplastic elastomer composition in the gas melting step is in the range of 100 to 240 ° C., and the temperature of the molten urethane-based thermoplastic elastomer composition in the cooling step is the temperature in the gas melting step. It is preferable that it exists in the range 10-100 degreeC lower than.

  The amount of carbon dioxide (B) added is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the urethane thermoplastic elastomer composition (A).

  The carbon dioxide (B) is preferably carbon dioxide (B-1) in a supercritical state.

  In the gas dissolving step, carbon dioxide is added by injecting it into a pump for discharging carbon dioxide while maintaining the carbon dioxide in a liquid state, and the discharge pressure of carbon dioxide from the pump is changed to a critical pressure of carbon dioxide (7 .4MPa) After discharging carbon dioxide from the pump so as to be a constant pressure within the range of 40MPa, the temperature of the discharged carbon dioxide is raised to a critical temperature of carbon dioxide (31 ° C) or higher and supercritical. The carbon dioxide is preferably added to the molten urethane-based thermoplastic elastomer composition.

  The urethane-based thermoplastic elastomer (A-1) is an amorphous polymer, a semi-crystalline polymer, a liquid crystal polymer, or a thermoplastic polymer containing at least one selected from the group consisting of urethane bonds, urea bonds, thiaurethane bonds, and thiourea bonds. In addition, at least one selected from the group consisting of elastomers is preferable.

The urethane-based thermoplastic elastomer composition foam according to the present invention further comprises a urethane-based thermoplastic elastomer (A-1) and another thermoplastic elastomer (A-2), and the (A-1) and (A -2) to the urethane-based thermoplastic elastomer composition (A) in a molten state having a mass ratio (A-1 / A-2) of 20/80 to 99/1, the urethane-based thermoplastic elastomer composition ( A) 0.1 to 30 parts by mass of carbon dioxide (B) is added to 100 parts by mass, and a molten urethane system in a mixed state of the urethane thermoplastic elastomer composition (A) and carbon dioxide (B). Obtained through a step of forming the thermoplastic elastomer composition (C) (gas dissolution step) and a step of lowering the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step).
The average cell diameter is 0.1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³ ,
Permanent elongation is 1% or more and 100% or less,
The bulk density is 0.03 or more and 1.10 g / cm ³ or less.

Furthermore, the urethane-based thermoplastic elastomer composition foam according to the present invention is a molten urethane-based thermoplastic elastomer composition (A), and 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). 0.1-30 parts by mass of carbon dioxide (B) is added, and a molten urethane-based thermoplastic elastomer composition (C) in a mixed state of the urethane-based thermoplastic elastomer composition (A) and carbon dioxide (B). Forming a gas (gas dissolving step);
A step of reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step);
The molten urethane-based thermoplastic elastomer composition (C) obtained through the gas melting step and the cooling step is filled or transferred into a space controlled at a lower pressure than the cooling step, and the molten urethane-based heat After generating cell nuclei in the plastic elastomer composition (C), it is obtained through a step of foaming while controlling the expansion ratio (foaming control step).
The average cell diameter is 0.1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³ ,
Permanent elongation is 1% or more and 100% or less,
The bulk density is 0.03 or more and 1.10 g / cm ³ or less.

  The laminate according to the present invention contains the urethane-based thermoplastic elastomer composition foam.

  The molded article according to the present invention comprises the urethane-based thermoplastic elastomer composition foam.

  According to the present invention, fine bubbles of uniform size are uniformly distributed throughout the foam, and the surface state is good, the appearance is excellent, and flexibility, mechanical properties, etc. In addition, a high-quality polyurethane foam can be obtained. In particular, by foaming with carbon dioxide, it can be provided smoothly and with high productivity without using chlorofluorocarbon or an organic solvent, and is excellent in environmental measures and safety.

  Furthermore, according to the present invention, since a thermoplastic resin (TPU or the like) is used as a raw material, it can be provided as a urethane-based thermoplastic resin material that is excellent in recyclability and has a low environmental load.

  Molded articles obtained from the foamed thermoplastic elastomer composition of the present invention are excellent in lightness, flexibility, heat insulation and surface appearance, for example, interior materials for automobiles, vehicles, ships, cushioning materials, heat insulation. It can be suitably used as an interior material for buildings such as materials and houses. The foam of the polyurethane-based thermoplastic elastomer composition of the present invention can be suitably used for a laminate.

  In the present invention, a predetermined amount of carbon dioxide is quantitatively and stably added to a molten urethane-based thermoplastic elastomer, and a urethane-based thermoplastic elastomer foam from a low-foam product to a high-foam product can be produced with a constant quality. . Moreover, the foam excellent in a softness | flexibility, heat insulation, and surface appearance can be obtained. Furthermore, since carbon dioxide is used as an alternative to conventional chlorofluorocarbons and butanes, there is no concern about air pollution or ozone layer destruction, and safety is also excellent.

The urethane-based thermoplastic elastomer composition foam according to the present invention is a foam composed of a thermoplastic polyurethane resin-containing composition containing 20% by mass or more of a thermoplastic polyurethane resin, and the average cell diameter of the foam is 0. .1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³
Permanent spread is 1% or more and 100% or less,
The bulk density is 0.03 or more and 1.10 g / cm ³ or less. This foam can be obtained, for example, by adding other thermoplastic resin or the like to thermoplastic polyurethane resin, if necessary, melting, mixing and foaming supercritical carbon dioxide.

  Hereinafter, the foam will be described first.

[A foam obtained from a composition containing a thermoplastic polyurethane resin]
The urethane-based thermoplastic elastomer composition foam of the present invention (hereinafter sometimes referred to as “foam”) is a foam comprising a thermoplastic polyurethane resin-containing composition containing 20% by mass or more of a thermoplastic polyurethane resin. And
The average cell diameter of the foam is 0.1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³
Permanent spread is 1% or more and 100% or less,
The bulk density is 0.03 or more and 1.10 g / cm ³ or less.

The average cell diameter is preferably 0.1 μm to 200 μm, preferably 0.1 μm to 10 μm.
More preferably 0 μm or less.

The average number of cells is preferably 10 ⁴ cells / cm ³ or more and 10 ¹⁶ cells / cm ³ or less, more preferably 10 ⁵ cells / cm ³ or more and 10 ¹⁶ cells / cm ³ or less.

  The permanent elongation is preferably 1% to 60%, more preferably 1% to 50%.

The bulk density is preferably 0.03 g / cm ³ or more and 1.0 g / cm ³ or less, more preferably 0.03 g / cm ³ or more and 0.9 g / cm ³ or less.

In the foam of the present invention, the difference (T _m1 −T _m2 ) between the melting point (T _m1 ) of the foam and the melting point (T _m2 ) when the foam is unfoamed is expressed by the following formula (1).
T _m1 -T _m2 ≧ 5 ℃ (1)
The difference (T _m1 −T _m2 ) is more preferably 10 ° C. or higher, and particularly preferably 15 ° C. or higher.

  The melting point when the foam is unfoamed is obtained by curing without foaming with the same resin composition as the thermoplastic polyurethane resin-containing composition containing 20% by mass or more of the thermoplastic polyurethane resin. It is the melting point of the composition.

  The insoluble matter in the foam of the present invention is preferably 10% by mass or more, more preferably 20% or more, and particularly preferably 50% by mass or more.

  The residue of the foam of the present invention after extraction with chloroform is preferably 20% by mass or more, more preferably 50% by mass or more. The residue after extraction of the foam with chloroform has a 5% weight reduction temperature. The temperature is preferably 180 ° C. or higher, more preferably 240 ° C. or higher.

  In addition, the chloroform insoluble matter of a foam is synonymous with the chloroform insoluble matter mentioned later (gel content).

  The residue after the foam is extracted with chloroform means that it is insoluble in chloroform and does not pass through a 300-mesh wire mesh.

  The 5% mass reduction temperature of the residue after the foam is extracted with chloroform means the 5% weight reduction temperature obtained by measuring the chloroform insoluble content by TG-DTA.

The MFR of the foam of the present invention is preferably 0.01 g / 10 min or more and 50 g / 10 min or less, more preferably 0.1 g / 10 min or more and 40 g / 10 min or less. When measuring the MFR of the foam, it is cut so that the maximum width of the foam is 3 mm or less, filled in a cylinder, left for 6 minutes, degassed and then measured.

  The heat of crystallization of the foam of the present invention is preferably 5 j / g or more, more preferably 8 j / g or more.

  When the foam of the present invention requires performance such as solvent resistance, heat resistance and permanent elongation, the foam preferably has an allophanate bond of 0.01 mmol / g or more with respect to the total mass of the foam, More preferably, it is desirable to contain 0.1 mmol / g or more.

  When the foam of the present invention requires performances such as water resistance, solvent resistance, and heat resistance, the urea bond is preferably 0.1 mmol / g or less, more preferably 0. It is desirable that it is contained in an amount of 05 mmol / g or less.

[Thermoplastic polyurethane resin]
The thermoplastic polyurethane resin used in the present invention is produced by reacting with an organic polyisocyanate compound used in the production of a normal thermoplastic polyurethane resin and a compound having active hydrogen, if necessary, in the presence of other additives. be able to. The active hydrogen compound is preferably a polyol or an active hydrogen compound containing a polyol as a main component. These may be used alone or in combination.

  The urethane-based thermoplastic composition foam according to the present invention is obtained by foaming a thermoplastic polyurethane resin-containing composition containing at least a thermoplastic polyurethane resin. In addition to the thermoplastic polyurethane resin, if necessary, Other thermoplastic resins may be included.

  In the thermoplastic polyurethane resin-containing composition, the thermoplastic polyurethane resin is 20 to 100% by mass, preferably 20 to 99% by mass, and more preferably based on the total amount of the thermoplastic polyurethane resin and other thermoplastic resins. Is preferably contained in a proportion of 40 to 95% by mass, particularly preferably 50 to 90% by mass.

  In this case, as described later, in the foaming method 1, a urethane-based thermoplastic resin and another thermoplastic elastomer are essential components, and in the foaming method 2, the other thermoplastic elastomer is used as necessary. About 20-100 mass% in the ratio of a plastic polyurethane resin is applied to the foaming method 2, and others can be applied to the foaming methods 1 and 2.

  The melt flow rate (ASTMD-1238-65T) of the thermoplastic polyurethane resin is preferably in the range of 0.5 to 50 g / 10 min, more preferably in the range of 0.5 to 20 g / 10 min, particularly preferably 0.5. What is in the range of -10/10 minutes is desirable.

  Among these thermoplastic polyurethane resins, it is preferable to use a urethane-based thermoplastic elastomer (A-1).

  Moreover, as another thermoplastic resin, another thermoplastic elastomer (A-2) is desirable.

  In addition to the thermoplastic polyurethane resin-containing composition, other additives such as a softening agent may be used in combination as necessary.

  Therefore, the thermoplastic polyurethane resin-containing composition used in the present invention is a urethane-based thermoplastic composed of a urethane-based thermoplastic elastomer (A-1) and, if necessary, another thermoplastic elastomer (A-2). It is desirable to use an elastomer composition (A).

  Therefore, also for the urethane-based thermoplastic elastomer composition (A) used in the second production method, the melt flow rate (ASTMD-1238-65T) is preferably in the range of 0.5 to 50 g / 10 min. Preferably it is in the range of 0.5 to 20 g / 10 min, particularly preferably in the range of 0.5 to 10/10 min.

  The urethane thermoplastic elastomer used in the second production method may be a single urethane thermoplastic elastomer or a plurality thereof.

  Hereinafter, the urethane-based thermoplastic elastomer (A-1) and other thermoplastic elastomers (A-2) will be described.

<Urethane-based thermoplastic elastomer (A-1)>
The urethane thermoplastic elastomer (A-1) is a resin synthesized by urethanizing an isocyanate compound, an active hydrogen compound such as a polyol compound, and a chain extender as necessary. These may be produced simultaneously with the production of the foam, may be produced in advance, or may be purchased and used commercially.

  As the isocyanate compound, an aromatic diisocyanate having 6 to 20 carbon atoms (excluding carbon in the NCO group), an aliphatic diisocyanate having 2 to 18 carbon atoms, an alicyclic diisocyanate having 4 to 15 carbon atoms, and 4 to 15 carbon atoms. Examples include araliphatic diisocyanates and modified products of these diisocyanates (urethane groups, carbodiimide groups, allophanate groups, urea groups, burette groups, uretdione groups, uretoimine groups, isocyanurate groups, oxazolidone group-containing modified products).

  Specific examples include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, dicyclomethane diisocyanate, isophorone diisocyanate, xylene diisocyanate, norbornane dimethyl isocyanate.

  Examples of the active hydrogen compound include a polyol compound and a polyamine compound.

  Specific examples of the polyol compound include ester-based, adipate-based, ether-based, lactone-based, and carbonate-based polyol compounds.

  Examples of chain extenders include low molecular diols and alkylene diamines.

  Examples of ester-based and adipate-based polyol compounds include polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, butenediol, hexanediol, pentanediol, neopentyldiol, and pentanediol, and adipic acid, sebacic acid, Examples thereof include compounds obtained by condensation reaction with dibasic acids such as azelaic acid, terephthalic acid, isophthalic acid, maleic acid and aromatic carboxylic acid.

  Examples of the ether-based polyol compound include polyethylene glycol, polypropylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

  Examples of the lactone-based polyol compound include polycaprolactone glycol, polypropiolactone glycol, and polyvalerolactone glycol.

Examples of carbonate-based polyol compounds include compounds obtained by dealcoholization reaction of polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, pentanediol, octanediol, and nonanediol with diethylene carbonate, dipropylene carbonate, and the like. Is mentioned.

(Commercially available urethane thermoplastic elastomer)
Commercially available urethane-based thermoplastic elastomers include, for example, Pelecene 2103 series (PTMG ether type), 2102 series (caproester type) 2355 series (polyester adipate type), 2363 series (PTMG ether type) (above trade names, Dow・ Chemical), Resamine P-1000 series and P-7000 series (adipate type ester type), P-2000 series (ether type), P-4000 series (caprolactone type), P-800 series (carbonate type) ( Product name, manufactured by Dainichi Seika Co., Ltd., Pandex T series (trade name, manufactured by DIC Bayer Polymer), Miractolan E type, P type (trade name, manufactured by Miraclan Japan), Elastollan (trade name, Takeda) Birthday Euretan Kogyo Co., Ltd.), Morusen (trade name, Morton Co. manufactured goods), and the like. (These are hereinafter sometimes referred to as thermoplastic polyurethane elastomers (TPU).)
Among the urethane-based thermoplastic elastomers, it is preferable to use an adipate-based resin since the amount of the foaming agent impregnated can be increased and the foaming pressure can be lowered. Furthermore, TPU having a resin hardness of 80 (Shore A) or less is more preferable because the foaming pressure can be processed at about normal pressure.

  Among such urethane-based thermoplastic elastomers (A-1), the melt flow rate (ASTMD-1238-65T) is preferably 0.5 to 50 g / 10 minutes, more preferably 0.5 to 20 g / 10 minutes. Particularly preferably, it is desirable to use a urethane-based thermoplastic elastomer (A-1) in the range of 0.5 to 10/10 minutes. The melt flow rate was measured according to ASTM D-1238-65T.

<Other thermoplastic elastomer (A-2)>
In applications where it is preferable that at least one kind of performance such as permanent elongation, heat resistance, melt tension, solvent resistance, water resistance, etc. is improved, the urethane-based thermoplastic elastomer (A-1) and other It is preferable to use a thermoplastic elastomer (A-2) in combination. When the melt tension is improved, a foam having a high expansion ratio can be obtained, and therefore, it is preferable that a low density foam or the like can be easily produced.

  As the other thermoplastic elastomer (A-2), the melt flow rate is preferably in the range of 0.01 g / 10 min or more and less than 50 g / 10 min, preferably in the range of 0.1 to 20 g / 10 min. It is more preferable that it is in the range of 0.2 to 20 g / 10 min.

  The melt flow rate was measured according to ASTM D-1238-65T.

  Such other thermoplastic elastomer (A-2) is a foaming method 2 in a mass ratio (A-1 / A-2 (the total is 100)) with the urethane thermoplastic elastomer (A-1). In the foaming methods 1 and 2, preferably 20/80 to 99/1, more preferably 40/60 to 95/5, particularly preferably 50/50 to 90 /. It is desirable to use at a ratio of 10.

  When other thermoplastic elastomer (A-2) is used in the above ratio, a foam having an excellent expansion ratio is obtained.

Moreover, the said urethane type thermoplastic elastomer composition (A) used by this invention is another heat different from a urethane type thermoplastic elastomer (A-1) as other thermoplastic elastomer (A-2) as needed. The plastic urethane elastomer may be contained in an amount of 50% by mass or more.

  Such other thermoplastic elastomers (A-2) that can be used in the present invention include styrene resins (for example, polystyrene, butadiene / styrene copolymers, acrylonitrile / styrene copolymers, acrylonitrile / butadiene / Styrene copolymer, etc.), ABS resin, polyethylene, polypropylene, ethylene-propylene resin, ethylene-ethyl acrylate resin, polyvinyl chloride, polyvinylidene chloride, polybutene, polycarbonate, polyacetal, polyarylene sulfide, polyphenylene sulfide, polyphenylene ether, polyphenylene Oxide, polyvinyl alcohol, polymethyl methacrylate, polyester resin (for example, polyethylene terephthalate, polybutylene terephthalate, etc.), raw material Polyester resins (eg, hydroxycarboxylic acid condensates such as polylactic acid, diol and dicarboxylic acid condensates such as polybutylene succinate), polyester elastomer (TPEE), polyamide resin, polyimide resin, polyparabanic acid, fluorine Examples thereof include resins, polysulfone, polyethersulfone, polyarylate, polyetheretherketone, and liquid crystal polymer.

  These may be used alone or in combination.

  Among these other thermoplastic elastomers (A-2), when an olefinic thermoplastic elastomer is used in combination, particularly in the case of a non-crosslinked rubbery substance, it may be mixed with a crosslinking agent and kneaded under heating. Polyisobutylene, butyl rubber, a propylene / ethylene random copolymer having a propylene content of 70 mol% or more, propylene / 1-butene random copolymer, etc. Is preferably used.

Of these, polyisobutylene and butyl rubber are preferable in terms of performance and handling. In particular, polyisobutylene and butyl rubber having a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 80 or less are preferable from the viewpoint of improving fluidity with respect to olefinic thermoplastic elastomers.

  When using the said other thermoplastic urethane elastomer (A-2), 5-60 mass parts, Preferably 5-30 mass parts in (A-2) in 100 mass parts of urethane type thermoplastic elastomer compositions (A). The ratio can be used.

<Other additives>
In the present invention, a softener (D), a plasticizer, a wax, a dispersant, a compatibilizer, a crosslinking agent, a crosslinking aid, a process oil, an anti-adhesion agent, a pigment, a weathering stabilizer, an antioxidant, a filler, Fiber reinforcing materials, colorants, crystallization accelerators, antibacterial / antifungal agents, antistatic agents, metal powders, and the like can be appropriately used according to the purpose and application.

  When it is preferable to improve the fluidity of the urethane-based thermoplastic elastomer composition (A), at least one of a plasticizer, a wax, a dispersant, a compatibilizing agent and the like is used in combination with the urethane-based thermoplastic elastomer composition. It is preferable to do.

  These other additives may be added independently at the time of production of the foam, or plural may be added at the same time. Furthermore, each is appropriately added to thermoplastic polyurethane or other thermoplastics added as necessary. You may add and use for an elastomer (A-2) etc.

(Softener (D))
The urethane-based thermoplastic elastomer composition (A) used in the present invention may be used in combination with a softening agent (D).

  As such a softening agent (D), usually, when rubber is rolled, the intermolecular force of the rubber is weakened to facilitate the process, and dispersion of carbon black or the like is aided or the hardness of the vulcanized rubber is lowered. At least, a high-boiling petroleum fraction used for the purpose of increasing flexibility can be mentioned. Such petroleum fractions can be classified into paraffinic, naphthenic, aromatic or the like.

  In the present invention, for example, a softener used for rubber can be used, and specifically, mineral oil softener, process oil, lubricating oil, paraffin, liquid paraffin, polyethylene wax, polypropylene wax, petroleum asphalt, petrolatum, etc. Synthetic petroleum substances, coal tars such as coal tar, coal tar pitch, fatty oils such as castor oil, linseed oil, rapeseed oil, soybean oil, coconut oil, waxes such as tall oil, beeswax, carnauba wax, lanolin, Synthetic polymers such as ricinoleic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, montanic acid, oleic acid, erucic acid and other fatty acids and / or metal salts thereof, petroleum resins, coumarone indene resins, atactic polypropylene, etc. , Dioctyl phthalate, dioctyl adipate, dioctyl sebake Ester plasticizers such as preparative other microcrystalline wax, liquid polybutadiene or its modified product or hydrogenated product, and liquid Thiokol and the like. Of these, mineral oil softeners are preferred.

  The amount of the softener (D) used is preferably 5 to 100 parts by mass, more preferably 5 to 80 parts by mass, and particularly preferably 5 to 50 parts by mass with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). It is desirable to use at a ratio of parts by mass.

  When the softening agent (D) is used at such a ratio, the fluidity of the urethane-based thermoplastic elastomer composition (A) can be improved without deteriorating the heat resistance and tensile properties of the foam.

(Plasticizer)
Examples of the plasticizer include di-n-butyl phthalate, di-2-ethylhexyl phthalate (DOP), di-n-octyl phthalate, diisodecyl phthalate, diisooctyl phthalate, octyl decyl phthalate, and butyl phthalate. Phthalic acid plasticizers such as benzyl, di-2-ethylhexyl isophthalate, di-2-ethylhexyl adipate (DOA), di-n-decyl adipate, diisodecyl adipate, dibutyl sebacate, di-2-sebacate Aliphatic ester plasticizers such as ethylhexyl, pyromellitic plasticizers such as trioctyl trimellitic acid and tridecyl trimellitic acid, tributyl phosphate, tri-2-ethylhexyl phosphate, 2-ethylhexyl diphenyl phosphate, tricresyl phosphate Phosphate plasticizers such as Epoxy plasticizers such as system soybean oil, include a polyester-based polymeric plasticizer, one or more of these can be used.

  When using a plasticizer, it is desirable to use it in an amount of 5 to 80 parts by mass, more preferably 10 to 60 parts by mass with respect to 100 parts by mass of the urethane-based thermoplastic elastomer (A-1). If it is less than 5 parts by mass, the soft resin properties and moldability are impaired, and if it exceeds 80 parts by mass, bleeding out may become significant. In addition, it is preferable to use an ester plasticizer from the viewpoint of thermal stability and suppression of bleedout.

(Wax)
Waxes improve the flow properties of TPU by acting as internal and external lubricants that reduce friction. It is also effective as a mold release agent for preventing sticking to, for example, a mold, and other additives such as pigments and antiblocking agents.
ents) and the like.

  For example, fatty acid esters such as stearic acid esters and montanic acid esters, as well as their metal soaps, and fatty acid amides such as stearic acid amides and oleic acid amides, higher fatty acid bisamides, and montanic acid ester waxes, polyethylene waxes Etc.

  As the higher fatty acid bisamide, a higher fatty acid bisamide obtained by a reaction of a saturated higher fatty acid having 14 to 35 carbon atoms and an aliphatic diamine having 1 to 10 carbon atoms is preferable. Examples of saturated higher fatty acids in that case include myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, cetic acid, serotic acid, heptacosanoic acid, montanic acid, Examples of aliphatic diamines include methylene diamine, ethylene diamine, trimethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, 1,7-diaminoheptane, 1,8- Examples include diaminooctane, 1,9-diaminononane, 1,10-diaminodecane and the like. Among the higher fatty acid bisamides obtained by the reaction of the saturated higher fatty acid and the aliphatic diamine, methylene bis stearic acid amide, ethylene bis stearic acid amide, tetramethylene bissteraric acid amide, hexamethylene bis stearic acid amide, ethylene Bismontanic acid amide, tetramethylene bismontanic acid amide, and hexamethylene bismontanic acid amide are preferable, and methylene bisstearic acid amide and / or ethylene bisstearic acid amide are more preferably used.

  When such waxes are used, the waxes are 10 parts by mass or less, preferably 5 parts by mass or less with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A).

(Dispersant)
Examples of the dispersant include (anhydrous) maleic acid modified polypropylene, (anhydrous) maleic acid modified polyethylene, amino modified low molecular weight polypropylene, amino modified low molecular weight polyethylene, terminal hydroxylated maleic acid modified polypropylene, terminal hydroxylated maleic acid modified. Examples thereof include polyethylene and a mixture of one or more thereof, and preferred are (anhydrous) maleic acid-modified polyethylene and (anhydride) maleic acid-modified polypropylene.

  The number average molecular weight of the dispersant is usually 1,000 to 100,000, preferably 1,000 to 50,000.

  When the dispersant is used, the dispersant is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A).

(Compatibilizer)
Examples of the compatibilizer include organopolysiloxane. Organopolysiloxanes include polydimethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, polymethylhydrogensiloxane, and / or these organopolysiloxanes modified with epoxy group-containing compounds, amino group-containing compounds, and ester bond-containing compounds. Modified organopolysiloxanes. Of these, polydimethylsiloxane is preferred from the viewpoints of dispersibility in the resin, solubility, and the effect of improving the surface appearance.

  The amount of the compatibilizer, for example, organopolysiloxane added is 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, and more preferably 0.8 parts by weight with respect to 100 parts by weight of the urethane-based thermoplastic elastomer composition (A). It is preferable to use in the range of 3-5 parts by mass. When the addition amount of the organopolysiloxane is less than 0.1 parts by mass, the effect of improving the surface appearance is poor, and when it is more than 10 parts by mass, the resin has a viscosity sufficient to withstand the gas pressure during foaming. Since it cannot hold | maintain and it becomes impossible to generate | occur | produce a bubble and produce a micro cell, it is not preferable.

(Crosslinking agent)
The urethane-based thermoplastic elastomer composition (A) of the present invention includes the urethane-based thermoplastic elastomer (A-1) and, if necessary, other thermoplastic elastomers (A-2), a softening agent (D) and the like. It is possible to obtain a cross-linked product containing, preferably by dynamically heat-treating in the presence of a cross-linking agent.

  The “dynamic heat treatment” refers to kneading the above components in a molten state.

  Examples of such cross-linking agents include organic peroxides, sulfur, phenol resins, amino resins, quinones and derivatives thereof, amine compounds, azo compounds, epoxy compounds, and the like generally used for thermosetting rubbers. Can be used. Of these, organic peroxides are particularly preferably used.

  Specific examples of the organic peroxide include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2, 5-di- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n -Butyl-4,4, -bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, diacetylperoxy , Lauroyl peroxide, etc. tert- butyl cumyl peroxide.

  Among these, in terms of odor and scorch stability, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di- (tert- Butylperoxy) hexyne-3,1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4 -Bis (tert-butylperoxy) valerate can be preferably used, and 1,3-bis (tert-butylperoxyisopropyl) benzene can be particularly preferably used.

  As the cross-linking agent, a bifunctional or higher functional isocyanate used as a raw material for ordinary polyurethane resins is preferably used.

  The crosslinking agent may contain a monofunctional or higher functional isocyanate derivative selected from the group consisting of polycarbodiimide, polyoxazolidine, and isocyanurate.

  More specifically, examples of the crosslinking agent include diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, metaxylylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, and dimer acid diisocyanate. An isocyanate group residual polymer obtained by reacting with these oligomers and polyols can also be used. Of these, diphenylmethane diisocyanate is preferably used because it is inexpensive and easily available.

  Among these, bis (4-isocyanatophenylmethyl) benzene isocyanate, bis (4-isocyanatophenylmethyl) diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and the like can be mentioned as particularly preferable ones.

  The isocyanates also include these carbodiimide-modified types or block-type polyisocyanate-modified products in which isocyanate groups are masked with phenols, lactams, or the like.

  Of these, particularly preferred polyisocyanates are polymethylene polyphenylene polyisocyanates having a number average molecular weight of 260 to about 800.

  The addition of tertiary amines, quaternary ammonium salts, phosphines, imidazoles and the like as catalysts for promoting the crosslinking reaction of polyisocyanates is not limited at all.

  Such a crosslinking agent is preferably added in an amount of 0.05 to 3 parts by mass, and more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). Is desirable.

(Crosslinking catalyst)
In order to carry out the crosslinking reaction more easily, a crosslinking catalyst can also be used. Examples of such catalysts include tertiary amine catalysts such as monoamines, diamines, triamines, cyclic amines, alcohol amines and ether amines, and organometallic compounds such as organotin compounds. However, when the cross-linking agent is a polyvalent amine and the cross-linkable functional group is an epoxy group, it is not necessary to use a catalyst because the amine and epoxy are sufficiently reactive.

  Moreover, as the usage-amount of the catalyst for bridge | crosslinking, when a crosslinkable functional group is an epixy group, for example, it is 0.1-5 equivalent with respect to an epoxy group, since an effect is small even if too much, 0.1-1 equivalent Is preferred. In the case of an isocyanate group, it may be 0.01 to 1% with respect to the polyisocyanate, but from the viewpoint of suppressing side reactions, it is preferably 0.01 to 0.2%.

  When such a crosslinking catalyst is used, the amount is preferably 0.05 to 3 parts by mass, more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). It is desirable to add.

(Crosslinking aid)
In the present invention, in the crosslinking treatment with the crosslinking agent, any one or more crosslinking aids selected from the group consisting of a peroxy crosslinking aid, a polyfunctional methacrylate monomer, and a polyfunctional vinyl monomer may be blended. it can.

  Examples of the peroxy crosslinking aid include sulfur, p-quinonedioxime, p, p′-dibenzoylquinonedioxime, N-methyl-N-4-dinitrosoaniline, nitrosobenzene, diphenylguanidine, and trimethylolpropane. -N, N'-m-phenylene dimaleimide and the like can be mentioned.

Examples of the polyfunctional methacrylate monomer include divinylbenzene, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate.

  Examples of the polyfunctional vinyl monomer include vinyl butyrate and vinyl stearate.

  By using such a crosslinking aid, a uniform and mild crosslinking reaction can be performed.

  In the present invention, among the crosslinking aids, divinylbenzene can be preferably used. Divinylbenzene is easy to handle, has good compatibility with the urethane-based thermoplastic elastomer (A-1) or other thermoplastic elastomer (A-2), which is the main component of the cross-linked product, and a crosslinking agent. To obtain a cross-linked urethane-based thermoplastic elastomer composition foam that has a uniform cross-linking effect by heat treatment and has a good balance between fluidity and physical properties. Can do.

  In the present invention, when such a crosslinking aid is used, it is preferably used in a proportion of 0.1 to 3% by mass, more preferably 0.3 to 2% by mass with respect to the entire cross-linked product. It is desirable.

  When the blending ratio of the crosslinking aid is within the above range, the resulting crosslinked urethane-based thermoplastic elastomer composition foam is foamed because the crosslinking aid does not exist as an unreacted monomer in the elastomer. However, there is no change in physical properties due to the heat history during molding. In addition, the fluidity during the molding process is excellent, and a molded body having a complicated shape can be easily obtained.

[Foaming agents, etc.]
(carbon dioxide)
Carbon dioxide used as a foaming agent in the present invention is 0.1 to 30 parts by mass relative to 100 parts by mass of the thermoplastic polyurethane resin-containing composition or a urethane-based thermoplastic elastomer composition (A) that is a preferred composition thereof, The amount is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 20 parts by mass, and particularly preferably 0.2 to 15 parts by mass.

  Carbon dioxide used as a foaming agent can be used alone, but carbon dioxide and nitrogen may be mixed and used. In this case, the mixing ratio is desirably in the range of 1: 9 to 9: 1 in terms of molar ratio.

  When the other thermoplastic resin (A-2) used for the foam is a polyester resin such as PET, PTEE, PBT, polylactic acid, polycarbonate, polyamide, etc. It is preferable to use nitrogen together because it is easy to reduce the cell size and increase the cell density.

  If the foaming agent is less than 0.1 parts by mass, a sufficient expansion ratio may not be obtained. When the amount exceeds 30 parts by mass, the expansion force of the added carbon dioxide is large, so that a blister-like appearance defect may occur on the surface of the foam. Since it is necessary to lengthen the time, the production efficiency may be reduced because the time required for production becomes long.

From the viewpoints of solubility, permeability, diffusibility, etc. in the melted urethane-based thermoplastic elastomer composition (A), these carbon dioxides are present inside the extruder and before and / or during the mixing of the urethane-based thermoplastic elastomer. It is preferable to be in a supercritical state.

(Foaming nucleating agent)
In the present invention, one or more pyrolytic foaming agents that generate carbon dioxide and / or nitrogen by thermal decomposition can be used in combination with carbon dioxide as a foam nucleating agent that makes foaming uniform.

  Specific examples of the foam nucleating agent include succinic acid, citric acid, succinic acid, baking soda or a mixture thereof. Of these, a sodium bicarbonate-citric acid mixture is preferable.

(Pyrolytic foaming agent)
Examples of such pyrolytic foaming agents include azodicarbonamide, 4,4′-oxybis (benzenesulfonyl hydrazide), p-toluenesulfonyl hydrazide, azobisisobutyronitrile, azodiaminobenzene, azohexahydrobenzo. Dinitrile, barium azodicarboxylate, N, N′-dinitrosopentamethylenetetramine, N, N′-dinitroso-N, N′-dimethylterephthalamide, t-butylaminonitrile, p-toluenesulfonylacetone hydrazone, etc. Organic pyrolytic foaming agents; inorganic pyrolytic foaming agents such as citric acid, sodium bicarbonate and ammonium carbonate can be mentioned.

  Among these, one kind or two or more kinds can be used. Among them, the azodicarbonamide-based foaming agent has a decomposition temperature higher than the melting temperature of the thermoplastic polyurethane composition, has excellent handling properties, has a large amount of gas generation, and has a decomposition behavior that is polyurethane. It is preferably used because it is suitable for melt molding of the composition. Of the above pyrolyzable foaming agents, for example, azodicarbonamide, 4,4′-oxybis (benzenesulfonylhydrazide), p-toluenesulfonylhydrazide, sodium bicarbonate, and the like have the effect of reducing the molecular weight of polyurethane. On the other hand, N, N′-dinitrosopentamethylenetetramine and the like have an action of promoting the crosslinking of polyurethane. Therefore, when a foaming agent that causes a decrease in the molecular weight of polyurethane and a foaming agent that promotes crosslinking are used in combination, the polyurethane is moderately crosslinked, and it is possible to suppress a decrease in melt viscosity, resulting in mechanical and physical properties. In addition, it is possible to form a foam having excellent chemical characteristics and a good foamed state.

  When such a pyrolytic foaming agent is used, the cell diameter of the obtained foam tends to be uniform.

  When using the said thermal decomposition type foaming agent, the usage-amount is with respect to 100 mass parts of urethane type thermoplastic elastomer compositions (A), Preferably it is 0.01-10 mass parts, More preferably, it is 0.01-5. The total amount of carbon dioxide and the pyrolytic foaming agent is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass.

(Other foaming additives)
As an additive for foaming of the urethane-based thermoplastic elastomer composition (A) used in the present invention, one type of various additives is used in order to improve the surface appearance of the foam without causing the foam to break. Or more can be added. As these additives, known ones used in ordinary foam molding can be used. For example, aliphatic carboxylic acids and derivatives thereof can be preferably used.

  Examples of such aliphatic carboxylic acids and derivatives thereof include aliphatic carboxylic acids, acid anhydrides, alkali metal salts, alkaline earth metal salts, and the like.

  As the aliphatic carboxylic acid, an aliphatic carboxylic acid having 3 to 30 carbon atoms is suitable. For example, lauric acid, stearic acid, crotonic acid, oleic acid, maleic acid, glutaric acid, and montanic acid are preferably used. . Of these, stearic acid, stearic acid derivatives, montanic acid and montanic acid derivatives are preferred from the viewpoint of dispersibility in the resin, solubility, surface appearance improvement effect, and the like, more preferably alkali metal salts of stearic acid and It is desirable to use an alkaline earth metal salt, particularly preferably zinc stearate or calcium stearate.

  The addition amount of these other foaming additives is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, particularly 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). Preferably it is in the range of 0.1-5 parts by mass.

  When the additive is added in an amount of 0.01 parts by mass or more, it is easy to prevent foam from breaking, and when it is 10 parts by mass or less, the resin can maintain a viscosity sufficient to withstand the gas pressure during foaming. The surface appearance can be improved without causing bubble breakage.

  In the present invention, an inorganic fine powder that acts as a foam nucleating agent can also be used as an additive for foaming the urethane-based thermoplastic elastomer composition (A).

  Examples of such inorganic fine powders include talc, calcium carbonate, clay, magnesium oxide, zinc oxide, glass beads, glass powder, titanium oxide, carbon black, and anhydrous silica. Of these, talc, calcium carbonate, titanium oxide, and anhydrous silica are preferable, and talc is more preferably used.

These inorganic fine powders preferably have a particle size of 50 μm or less, more preferably 10 μm.
It is not more than μm, particularly preferably not more than 5 μm.

When the particle size of the inorganic fine powder is 50 μm or less, the cell diameter of the foam is reduced, the Izod impact strength can be improved, and the surface appearance is improved.

  When the inorganic fine powder is added, the addition amount is preferably 0.01 to 40 parts by mass, more preferably 0.05 to 20 parts by mass, with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). Preferably it is 0.05-10 mass parts, Most preferably, it exists in the range of 0.1-5 mass parts.

  When the addition amount of the inorganic fine powder is in the range of 0.01 to 40 parts by mass, the surface appearance of the foam can be made better.

[Method for producing foamed urethane-based thermoplastic elastomer composition]
The first method for producing a urethane-based thermoplastic elastomer composition foam according to the present invention is a step of melting carbon dioxide by melting a thermoplastic polyurethane resin, if necessary, other thermoplastic resins, additives, and the like ( Gas melting step) and a step of cooling the melt obtained in the melting step (cooling step).

  Furthermore, in the second method for producing the urethane-based thermoplastic elastomer composition foam of the present invention, the melt obtained through the cooling step is filled or transferred into a space controlled at a lower pressure than the cooling step. Then, after the cell nucleus is generated in the molten urethane-based thermoplastic elastomer composition, the step of foaming while controlling the expansion ratio (foaming control process) is included.

  Among these, in the first production method, a urethane-based thermoplastic resin and other thermoplastic elastomers are essential components, and includes the gas dissolving step and the cooling step, and after passing through the cooling step, or the cooling step The method for producing a foam to be foamed may be referred to as a foaming method 1, and this method does not necessarily require a step of controlling the foaming ratio.

  In the second manufacturing method, the manufacturing method including the gas dissolving step, the cooling step, and the foaming control step may be referred to as a foaming method 2.

  When obtaining a foam excellent in solvent resistance, heat resistance and permanent elongation as a foam, it is desirable that the thermoplastic polyurethane resin contains a urethane-based thermoplastic elastomer. Specifically, as the thermoplastic polyurethane resin, The urethane-based thermoplastic elastomer (A-1) is preferable, and as the other resin, other thermoplastic elastomer (A-2) can be preferably used, and the urethane-based thermoplastic elastomer composition (A) composed of these is a resin. It is preferably used as a component.

  The said manufacturing method can be used suitably for manufacture of the foam which consists of a composition containing the said thermoplastic polyurethane resin. Hereinafter, the production method will be described in detail.

  In the method for producing a foam of the present invention, when a foam excellent in solvent resistance, heat resistance and permanent elongation is obtained as the foam, dynamic crosslinking is preferably performed in the method for producing the foam. The dynamic crosslinking is preferably completed by 70% or more of the crosslinking in the gas dissolution step and the cooling step, and it is particularly preferable that the dynamic crosslinking is mainly performed in the gas dissolution step.

  In this specification, the term “cross-linking” means that the apparent molecular weight of the polymer in the composition increases as a result of many cross-linking reactions in the competitive reaction between the decomposition reaction and the cross-linking reaction that occur when the polymer is thermally reacted with the cross-linking agent. The term “decomposition” means a phenomenon in which the apparent molecular weight of a polymer decreases as a result of many decomposition reactions.

  Dynamic crosslinking means performing crosslinking by the following dynamic heat treatment.

  Dynamic heat treatment is a method that uses a kneading device such as an open type mixing roll, a non-open type Banbury mixer, a kneader, a single or twin screw extruder, a continuous mixer, etc., and a non-open type kneading device. It is preferable to carry out with. The dynamic heat treatment is preferably performed in an atmosphere of an inert gas such as nitrogen or carbon dioxide.

The kneading is preferably performed at a temperature at which the half-life of the crosslinking agent used is less than 1 minute. The kneading temperature is usually preferably 140 to 240 ° C., more preferably 160 to 230 ° C., and the kneading time is preferably 1 to 20 minutes, more preferably 1 to 5 minutes. In addition, the shearing force applied during kneading is usually determined at a shear rate of preferably 10 to 10 ⁴ sec ⁻¹ , more preferably 10 ² to 10 ⁴ sec ⁻¹ .

In addition, when obtaining what is excellent in solvent resistance, heat resistance, permanent elongation, etc. as a foam, in the said foaming method 2, a urethane type thermoplastic elastomer (A-1) and another thermoplastic elastomer (A-). 2) and, if necessary, a mineral oil softener (D) and the like are mixed in advance, uniformly kneaded into pellets, and the resulting pellets and a crosslinking agent dissolved in divinylbenzene are necessary. Further, a crosslinking aid, a vulcanization accelerator, and the like are further uniformly mixed using a known equipment such as a tumbler type Brabender, a V type Brabender, or a Henschel mixer. The mixing is preferably 50 ° C. or lower. The conditions for pelletization can be selected as appropriate.

When producing a foam using such foaming method 2, the urethane-based thermoplastic elastomer composition (A) used in the present invention is the urethane-based thermoplastic elastomer (A-1), if necessary, other It is preferable to obtain a cross-linked product containing the thermoplastic elastomer (A-2), mineral oil softener (D) and the like, preferably by dynamically heat-treating in the presence of a cross-linking agent.

  Hereinafter, the foaming methods 1 and 2 will be described in detail from the foaming method 2.

<Foaming method 2>
In the present invention, the foaming method 2 is performed by adding 0.1 to 30 parts by mass of carbon dioxide with respect to 100 parts by mass of the molten thermoplastic polyurethane resin, and mixing the molten thermoplastic polyurethane resin composition. The molten thermoplastic polyurethane composition obtained through the step of forming (gas dissolving step) and then the step of lowering the temperature of the molten thermoplastic polyurethane composition (cooling step) is controlled to a pressure lower than that of the cooling step. Foaming a thermoplastic polyurethane resin composition, which includes filling or transferring into a space, generating cell nuclei in the molten thermoplastic polyurethane resin composition, and foaming while controlling a foaming ratio (foaming control process) It is a manufacturing method of a body.

  The thermoplastic polyurethane resin is preferably a molten urethane-based thermoplastic elastomer composition.

  When obtaining a foam excellent in solvent resistance, heat resistance and permanent elongation as a foam, the thermoplastic polyurethane resin is a urethane-based thermoplastic elastomer (A-1), and if necessary, other thermoplastic resins and minerals. An oil-based softener is preferably included.

  That is, it is preferable to use a urethane-based thermoplastic elastomer composition (A) in a molten state composed of a urethane-based thermoplastic elastomer (A-1) and, if necessary, other thermoplastic elastomer (A-2). The amount used is as described above. And 0.1-30 mass parts carbon dioxide is added and mixed with respect to 100 mass parts of this urethane type thermoplastic elastomer composition (A), and a molten urethane type thermoplastic elastomer composition (C) is formed. The molten urethane-based thermoplastic elastomer composition (C) obtained through the step (gas dissolving step) and then the step of reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step) is cooled. Filling or transferring to a space controlled at a lower pressure than the process, generating cell nuclei in the molten urethane-based thermoplastic elastomer composition (C), and then foaming while controlling the expansion ratio (foam control) And a process for producing a urethane-based thermoplastic elastomer composition foam comprising a step).

  In the gas dissolution step, if necessary, it may contain an aliphatic carboxylic acid and its derivative, a foam nucleating agent, an inorganic fine powder, etc. If it is a range which does not inhibit the effect of the present invention, it may be in a state containing a thermally decomposable foaming agent in the gas dissolution step.

  Each step will be described below. As a thermoplastic polyurethane resin, a urethane-based thermoplastic in a molten state, which is composed of a urethane-based thermoplastic elastomer (A-1) and, if necessary, another thermoplastic elastomer (A-2). The case where the elastomer composition (A) is used may be described as an example.

(Gas dissolution process)
In the gas melting step, the melting temperature of the thermoplastic polyurethane resin (preferably the urethane-based thermoplastic elastomer composition (A)) is preferably 100 to 240 ° C, more preferably 110 to 240 ° C, and particularly preferably 140 to 230. ° C.

  In the gas melting step, the foaming agent may be added to the molten urethane-based thermoplastic elastomer composition (A) by, for example, injecting gaseous carbon dioxide directly or in a pressurized state, or liquid dioxide dioxide. The method of adding carbon with a plunger pump etc. is mention | raise | lifted.

  In the gas melting step, the added carbon dioxide (B) is a constant pressure within a range of the critical pressure of carbon dioxide (7.4 MPa) to 40 MPa, and a temperature equal to or higher than the critical temperature of carbon dioxide (31 ° C.). It is preferable to add carbon dioxide in a supercritical state to a molten urethane-based thermoplastic elastomer composition.

  Further, in the method for adding carbon dioxide in the gas dissolving step, carbon dioxide is injected into a pump for discharging carbon dioxide while maintaining the liquid state, and the discharge pressure of carbon dioxide from the pump is changed to the critical pressure of carbon dioxide. (7.4MPa) After discharging carbon dioxide from the pump so as to be a constant pressure within a range of 40MPa, the temperature of the discharged carbon dioxide is raised to the carbon dioxide critical temperature (31 ° C) or higher. The supercritical carbon dioxide is preferably added to the molten urethane-based thermoplastic elastomer composition.

  For example, FIG. 1 is a schematic view showing an example of a method for producing a urethane-based thermoplastic elastomer composition foam. As shown in FIG. 1, carbon dioxide is maintained in a liquid state from a liquefied carbon dioxide cylinder (4). As is, it is injected into the metering pump (5), and the discharge pressure of the metering pump (5) is controlled by the pressure-holding valve (7) so that the discharge pressure of the metering pump (5) becomes a constant pressure within the range of critical pressure (7.4 MPa) to 40 MPa. Then, after raising the temperature to the critical temperature (31 ° C.) or higher of carbon dioxide to form supercritical carbon dioxide, a method of adding it to the molten urethane-based thermoplastic elastomer composition (A) is preferably used.

(Cooling process)
In the cooling step, the temperature is equal to or higher than the plasticizing temperature of the molten thermoplastic polyurethane composition (preferably a molten urethane-based thermoplastic elastomer composition (C)) obtained in the gas melting step, and is equal to or lower than the melting temperature in the gas melting step. To lower. The temperature of the molten thermoplastic polyurethane resin composition (preferably a molten urethane-based thermoplastic elastomer composition (C)) obtained in the gas dissolving step is preferably in the range of 10 to 100 ° C. lower than that in the gas dissolving step. .

  In the cooling step, the molten thermoplastic polyurethane resin composition obtained in the gas dissolving step is preferably set to a temperature range of 50 to 230 ° C, more preferably 80 to 220 ° C.

In the molten thermoplastic polyurethane resin composition (preferably a molten urethane-based thermoplastic elastomer composition (C)) thus obtained, carbon dioxide is separated until the gas dissolving step and the cooling step are completed. Preferably, the pressure and temperature in the system in which the molten urethane-based thermoplastic elastomer composition is present in the gas melting step and the cooling step are set to a critical pressure of carbon dioxide (7.4 MPa) or more. Critical temperature (31
It is preferable to maintain above (degree C).

(Foaming control process)
The molten thermoplastic polyurethane resin composition obtained through the gas melting step and the cooling step (preferably a molten urethane-based thermoplastic elastomer composition (C). Hereinafter, a molten urethane-based thermoplastic elastomer composition ( C) will be described as an example.) May further include a foam control step for foaming the composition.

  In the foam control process, the molten urethane-based thermoplastic elastomer composition (C) is filled or transferred into a space controlled at a lower pressure than the cooling process, and the cell nucleus is contained in the molten urethane-based thermoplastic elastomer composition (C). Is a step of foaming while controlling the expansion ratio.

  The space for generating cell nuclei and the space for controlling the expansion ratio may be common or may be independent spaces. In the case of a common space, the expansion ratio is controlled by the pressure loss of the molten urethane-based thermoplastic elastomer composition (C) that moves while foaming inside the space. When the expansion ratio is controlled in an independent space, the pressure can be controlled independently of the cell nucleus generation space. In this case, the expansion ratio is also determined by the pressure loss of the resin that moves while foaming inside the space. Can be controlled.

  In addition, the expansion ratio is controlled by, for example, cooling the molten urethane-based thermoplastic elastomer composition (C) below the crystallization temperature after the generation of cell nuclei and controlling the growth of the generated cell nuclei. You can also.

The pressure in the cell nucleus generation space is preferably controlled to a pressure that is 0.1 MPa or more and 20 MPa or less lower than that in the cooling step, and is more preferably controlled to a pressure that is 0.1 MPa or more and 15 MPa or less.

In the case where the expansion ratio is controlled while causing pressure loss inside the space, the pressure measured immediately after the start of the cooling process, that is, until 2D (meaning twice the screw diameter) has elapsed since the start of the cooling process. Immediately after becoming the cell nucleus generation space from the cooling process, specifically, 2D
The standard is the one determined by the pressure difference measured until the time has passed.

The specific pressure in the cell nucleus generation space is preferably 7.4 MPa or more and 20 MPa or less,
More preferably, the pressure is 7.4 MPa or more and 15 MPa or less.

  When the expansion ratio is controlled while causing pressure loss inside the space, the pressure is measured in the same manner as described above until the measurement difference of the pressure difference is changed from the cooling step to the cell nucleus generation space. Referenced to those measured between

When the expansion ratio is controlled independently of the cell nucleation space, the pressure is preferably controlled to a pressure lower by 0.1 MPa or more and 10 MPa or less than the cell nucleation space, and a pressure lower by 0.1 MPa or more and 5 MPa or less. More preferably, it is controlled.

  In this case, the specific pressure in the expansion ratio control space is preferably 7.4 MPa or more and 20 MPa or less, and more preferably 7.4 MPa or more and 10 MPa or less.

  In the case where the expansion ratio is controlled while causing a pressure loss inside the space, as described above, the pressure is measured immediately after the pressure difference is changed from the cell nucleus generation space to the expansion ratio control space. It is based on what was measured until 2D passed from the space start point.

For example, as the foaming control step, specifically, a certain amount of the molten urethane thermoplastic elastomer composition is filled or transferred into a space for foaming, such as a mold, by an injection device or the like. For example, in the case of a mold, the molten urethane-based thermoplastic elastomer composition transferred by injection into the mold or in the case of a die is filled into a space for foaming such as a mold or a die. The product (C) is produced by, for example, generating cell nuclei in the molten urethane-based thermoplastic elastomer composition (C) by foaming by reducing the pressure of the space for foaming in a mold or a die, and foaming, A urethane-based thermoplastic elastomer composition foam (in the case of a molten thermoplastic polyurethane resin composition, a thermoplastic polyurethane resin composition foam) can be obtained.

  Examples of the molding of the urethane-based thermoplastic elastomer composition foam in the present invention include extrusion molding, injection molding, blow molding, extrusion blow molding, injection blow molding, inflation molding, stamping molding, compression molding, and bead molding. A molding machine used in the known resin processing method can be applied. In addition, the continuous plasticizing apparatus mentioned later is contained in these molding machines.

  The urethane-based thermoplastic elastomer composition foam of the present invention is not particularly limited in its product shape. For example, the urethane-based thermoplastic elastomer composition foam obtained by extrusion molding is also in the form of a sheet, plate, square, pipe, tube, column, ellipse, paddy, strand, powder , Beads, filaments, nets, profile extrusion, multilayer extrusion, wire coating, and the like are not particularly limited.

  Further, the urethane-based thermoplastic elastomer composition foam of the present invention is not particularly limited in terms of the expansion ratio, but a low-foamed product of 1 to 4 times and a highly foamed product of 4 to 50 times are practically or industrially usable. Suitable for typical production.

<Foaming method 1>
The foaming method 1 of the present invention comprises an elastomer made of a thermoplastic resin other than urethane (other heat) with respect to 20 parts by mass or more and 99 parts by mass or less of a thermoplastic polyurethane resin (preferably a urethane-based thermoplastic elastomer (A-1)). 100 parts by mass of a thermoplastic polyurethane resin composition in a molten state (preferably a urethane-based thermoplastic elastomer composition (A)) containing 80 parts by mass or less, preferably 1 to 80 parts by mass of a plastic elastomer (A-2)) (I.e., the upper limit of the content of (A-2) is 80 parts by mass) 0.1 to 30 parts by mass of carbon dioxide is added, and the thermoplastic polyurethane resin composition and carbon dioxide are added. Of foam, including a step of mixing and dissolving (gas dissolving step) and a step of reducing the temperature of the melt obtained in the gas dissolving step (cooling step) It is a method. When a foam excellent in solvent resistance, heat resistance and permanent elongation is obtained as the foam, the thermoplastic polyurethane resin is preferably a urethane-based thermoplastic elastomer.

  For example, after uniformly mixing the urethane-based thermoplastic elastomer (A-1), the above-mentioned additives, and other thermoplastic elastomers (A-2) as necessary with a high-speed stirrer, etc. It can be produced by a melt kneading method using a multi-screw extruder, a mixing roll, a kneader, a Brabender, or the like. Further, it is possible to use the urethane-based thermoplastic elastomer (A-1), the above additives and the like and, if necessary, other thermoplastic elastomer (A-2) in a uniformly mixed state.

  Thus, the urethane-based thermoplastic elastomer composition (A) crosslinked can be obtained.

  When adopting extrusion molding as a method for preparing the urethane-based thermoplastic elastomer composition (A), the urethane-based thermoplastic elastomer (A-1) and other thermoplastic elastomers (A-2) may be used. desirable. In this case, among 100 parts by mass of the urethane-based thermoplastic elastomer composition (A), preferably (A-1) is 40 to 95 parts by mass, (A-2) is 1 to 60 parts by mass, and more preferably (A -1) 60-95 parts by mass, (A-2) 1-25 parts by mass, particularly preferably (A-1) 70-95 parts by mass, and (A-2) 1-10 parts by mass. It is desirable to use in. When the other thermoplastic elastomer (A-2) is used in such a proportion, a foam composition having a high expansion ratio that is difficult to obtain with the urethane-based thermoplastic elastomer (A-1) alone and has excellent flexibility and heat resistance. can get. In addition, the said numerical value is a ratio with respect to the total amount of the said urethane type thermoplastic elastomer (A-1), another thermoplastic elastomer (A-2), and another additive.

  Such a gas dissolving step, a cooling step, etc. in the foaming method 1 can be carried out in the same manner as in the foaming method 2.

(Urethane-based thermoplastic elastomer composition foam production equipment)
In order to obtain a urethane-based thermoplastic elastomer composition foam based on the production method of the present invention, a production apparatus to which the same conditions as in the production method are applied may be used.

  In this case, in the foaming method 1 or 2, in the cooling means corresponding to the cooling step, the molten thermoplastic polyurethane resin composition obtained in the gas dissolving step is preferably in a temperature range of 110 to 230 ° C. In the range of ˜220 ° C., it is necessary to configure so as to be lower than the plasticizing temperature of the molten urethane-based thermoplastic elastomer composition and lower than the melting temperature in the gas melting step. It comprises on the same conditions according to a manufacturing method.

(Specific example of production method of urethane-based thermoplastic elastomer composition foam)
An example of a method for producing the foam of the present invention by injection molding will be described in more detail with reference to FIG.

  An injection device (2) having an injection plunger (11) via an opening / closing valve (10) on a resin plasticizing cylinder (1) having a line for adding a foaming agent to the molten urethane-based thermoplastic elastomer composition (A). ). The urethane-based thermoplastic elastomer composition is fed into the resin plasticized cylinder (1), and carbon dioxide is added while heating and melting to form a compatible molten urethane-based thermoplastic elastomer composition.

  Thereafter, the molten urethane-based thermoplastic elastomer composition is fed into an injection device (2) having an injection plunger (11). After being sent in, the resin plasticizing cylinder (1) and the injection device (2) become independent from each other by closing the opening / closing valve (10). The resin plasticizing cylinder (1) melts continuously without stopping while measuring and injecting the molten urethane-based thermoplastic elastomer composition filled in the mold (3) by the injection device (2). A urethane-based thermoplastic elastomer composition is formed. In this case, since the pressure is not measured in the injection device (2), the pressure in the resin plasticizing cylinder (1) increases, but the compatibility state of the molten urethane-based thermoplastic elastomer composition is not broken by the increase in pressure. Therefore, there is no problem in continuing the gas dissolution process and the cooling process. However, when a problem arises in the pressure resistance of the resin plasticizing cylinder (1), it is also possible to provide a device that can discharge the molten urethane-based thermoplastic elastomer composition out of the system by operating the on-off valve (10). Do not depart from the spirit.

  On the other hand, the injection device (2) performs the injection after the metering is finished, but in the normal injection molding machine, the back pressure is temporarily cut after the metering is finished. A back pressure is always maintained so that the thermoplastic elastomer composition does not separate. The back pressure at this time may be a minimum pressure at which the foaming agent and the urethane-based thermoplastic elastomer composition are not separated, but is preferably equal to or higher than the critical pressure of the foaming agent.

  In this way, the molten urethane-based thermoplastic elastomer composition formed in the resin plasticizing cylinder (1) does not cause phase separation between the foaming agent and the urethane-based thermoplastic elastomer composition, and the mold (3) Is injected into.

  In the mold (3), after injecting the molten urethane-based thermoplastic elastomer composition, degassing of the high-pressure gas filled in the mold (3) and / or part or all of the mold (3) core The foam control process is performed by retreating.

  One embodiment of the present invention by injection molding is shown in FIG. An open / close valve (10) is provided between a resin plasticizing cylinder (1) having a line for adding a foaming agent to a molten urethane-based thermoplastic elastomer composition and an injection device (2) having an injection plunger (11). Providing an adapter (12) having a mixing section connected to the outflow passage of the resin plasticizing cylinder (1) connected to the injection device (2) via a molten thermoplastic elastomer composition and carbon dioxide Mixing of the urethane-based thermoplastic elastomer composition and the formation of a compatible state between the urethane-based thermoplastic elastomer composition and carbon dioxide, and by controlling the temperature of the adapter (12), the molten urethane-based thermoplastic elastomer composition is obtained. It becomes easy to cool to a viscosity suitable for later injection and foaming.

  Although there is no restriction | limiting in particular about the adapter (12) which has this mixing part, Since the molten urethane type thermoplastic elastomer composition is knead | mixed and cooled, the adapter (12) incorporating a static mixer is used suitably.

  One embodiment of the injection molding of the present invention is shown in FIG. Resin accumulator device (14) having a resin accumulator plunger (13) connected to the injection device (2) via an on-off valve (10) before the injection device (2) having an injection plunger (11) After the metering is completed, the opening / closing valve (10) is switched to the closed state, and while the injection plunger (11) performs injection into the mold (3), the resin plasticizing cylinder (1) The molten urethane-based thermoplastic elastomer composition sent is sent to the resin accumulator device (14) provided immediately before the opening / closing valve (10), and by the inflow of the molten urethane-based thermoplastic elastomer composition, By controlling the resin accumulator device (14) that the plunger of the resin accumulator device (14) is retracted, a predetermined pressure is applied in the apparatus system. Easier to maintain, easy maintenance of the mixed state of the molten urethane-based thermoplastic elastomer composition is preferable because the surface appearance of the foam is improved.

  One embodiment of the injection molding of the present invention is shown in FIG. Furthermore, it is also possible to provide an injection device (2) having another injection plunger (11) instead of the resin accumulator device (14) having a plunger, and maintaining the inside of the device system at a predetermined pressure. It is preferable because it is easy to maintain a compatible state of the molten urethane-based thermoplastic elastomer composition and the surface appearance of the foam becomes good.

  1-4, in the case of an injection molding machine in which the resin plasticizing cylinder (1) and the injection device (2) are independent, the urethane-based thermoplastic elastomer composition and the foaming agent are not separated. Since it is easy to maintain the pressure in the system, it is easy to produce the foamed thermoplastic elastomer composition targeted by the present invention. However, the back pressure is always applied during metering injection while dissolving the gas and cooling. If the injection molding machine can be applied, the urethane-based thermoplastic elastomer composition foam of the present invention can be produced even with an in-line screw type injection molding machine (15) as shown in FIG.

  The gas dissolving step for forming the mixed state of the urethane-based thermoplastic elastomer composition and carbon dioxide in the present invention is a resin plastic in the example of the method for producing a urethane-based thermoplastic elastomer composition foam shown in FIG. In this step, the urethane-based thermoplastic elastomer composition is heated and melted in the plasticizing cylinder (1), and then carbon dioxide is added to the melted urethane-based thermoplastic elastomer composition and mixed uniformly.

  The cooling step or cooling means is a step of cooling the molten urethane-based thermoplastic elastomer composition and adjusting the viscosity so as to be suitable for injection and foaming.

  Such a gas dissolution step and a cooling step are performed by a resin plasticizing cylinder (1) and an adapter (12) in the example of the method for producing a urethane-based thermoplastic elastomer composition foam shown in FIG. Moreover, in the example of the manufacturing method of the urethane type thermoplastic elastomer composition shown in FIG. 3, it carries out with the resin plasticization cylinder (1), the adapter (12), and the resin accumulator apparatus (14).

  The foaming control step measures the temperature-controlled molten urethane-based thermoplastic elastomer composition to the injection device (2) so that the viscosity is suitable for injection and foaming, and performs injection with the injection plunger (11). In this step, the molten urethane thermoplastic elastomer composition injected into the mold (3) is subjected to foaming by reducing the pressure under pressure, generating cell nuclei and controlling the expansion ratio.

  Among these, at least the gas dissolving step and the cooling step can be performed as follows according to the method described in JP-A-8-11190.

  In FIG. 1, a urethane-based thermoplastic elastomer composition is fed into a resin plasticizing cylinder (1) from a hopper (16) and melted at a temperature equal to or higher than the melting point of the urethane-based thermoplastic elastomer composition or the plasticizing temperature. The temperature at this time is 120-240 ° C. for heat melting. Carbon dioxide is injected from a liquefied carbon dioxide cylinder (4) into a metering pump (5), where the pressure is increased, and the pressure-controlled carbon dioxide is melted into a urethane-based thermoplastic elastomer in the resin plasticizing cylinder (1). Add to composition. At this time, carbon dioxide present in the resin plasticizing cylinder (1) significantly increases the dissolution and diffusion of the molten urethane-based thermoplastic elastomer composition, and in the molten urethane-based thermoplastic elastomer composition in a short time. In order to allow permeation, the inside of the system is preferably maintained at a critical pressure (7.4 MPa) or higher and a critical temperature (31 ° C.) or higher.

  Further, it is preferable that the temperature is increased before being added to the melted urethane-based thermoplastic elastomer composition in the resin plasticizing cylinder (1) and added after becoming supercritical.

  The urethane-based thermoplastic elastomer composition and carbon dioxide melted in the resin plasticizing cylinder (1) are kneaded by the screw (17) to form a compatible state of the urethane-based thermoplastic elastomer composition and carbon dioxide. In the cooling step after the compatibilization, the temperature of the tip of the resin plasticizing cylinder (1) is controlled so that the molten urethane-based thermoplastic elastomer composition has a temperature equal to or higher than the plasticizing temperature of the molten urethane-based thermoplastic elastomer composition. Cooling to a temperature not higher than 50 ° C. higher than the plasticizing temperature of the elastomer composition and not higher than the melting temperature in the gas dissolving step. The temperature range at this time is 110 to 230 ° C., preferably 130 to 220 ° C. and is cooled to a temperature equal to or higher than the plasticizing temperature of the molten urethane-based thermoplastic elastomer composition, and becomes a viscosity suitable for subsequent injection and foaming. Adjust as follows.

  An example of the present invention will be described in more detail with reference to the drawings. 1-5, (1) is a resin plasticizing cylinder, (2) is an injection device, (3) is a mold, (4) is a liquefied carbon dioxide cylinder, (5) is a metering pump, and (10) is open / close (11) is an injection plunger, (12) is an adapter, (13) is a resin accumulator plunger, (14) is a resin accumulator device, (15) is an inline screw type injection molding machine, (16) is a hopper, (17) is a screw, (18) is a gas cylinder, (19) is a pressure control valve, and (20) is an on-off valve.

In the case of carbon dioxide, the critical pressure is 7.4 MPa, the critical temperature is 31 ° C., and the pressure in the resin plasticizing cylinder (1) is 7.4 to 40 MPa, preferably 10 to 30 MPa, and the temperature is 110 It is desirable that the temperature is in the range of ˜300 ° C., preferably 130 ° 280 ° C., more preferably 240 ° C. or less, and particularly preferably 130 ° C. to 235 ° C.

  In addition, carbon dioxide as a foaming agent may be added after being heated to a supercritical state before being added to the molten urethane-based thermoplastic elastomer composition in the resin plasticizing cylinder (1) and being supercritical. preferable.

  The urethane-based thermoplastic elastomer composition and carbon dioxide melted in the resin plasticizing cylinder (1) are kneaded by the screw (17) to form a compatible state of the urethane-based thermoplastic elastomer composition and carbon dioxide. In the cooling step after compatibilization, the temperature of the tip of the resin plasticizing cylinder (1) is controlled so that the molten urethane-based thermoplastic elastomer composition has a temperature of 110-230 ° C, preferably 130-220 ° C, and the molten urethane-based thermoplastic elastomer composition Cool above the plasticization temperature of the product and adjust the viscosity to be suitable for subsequent injection and foaming.

  A molten urethane-based thermoplastic elastomer composition whose temperature is controlled so as to have a viscosity suitable for injection and foaming is an injection plunger (11) connected via an on-off valve (10) at the beginning of the foam control process. ) To the injection device (2). When the on-off valve (10) is open, the molten urethane-based thermoplastic elastomer composition is metered by the retraction of the injection plunger (11) as it flows into the injection device (2).

  In any type of injection molding machine such as an inline screw type or a plunger type, the back pressure stops immediately after the end of measurement in a normal injection molding machine. In the present invention, at this time, in the injection device (2), Control the internal pressure by applying back pressure until the end of injection so that the molten urethane-based thermoplastic elastomer composition does not separate into a foaming agent and thermoplastic elastomer composition, and the molten urethane-based thermoplastic elastomer composition does not foam. It is necessary to continue.

  The back pressure at this time is kept at a minimum so that the molten urethane-based thermoplastic elastomer composition does not separate into the foaming agent and the urethane-based thermoplastic elastomer, and the molten urethane-based thermoplastic elastomer composition does not foam. However, the pressure is preferably not less than the critical pressure of carbon dioxide. Until the series of metering steps in the gas dissolution process, cooling process and foam control process is completed, the pressure is always maintained, and the molten urethane-based thermoplastic elastomer composition is separated into the urethane-based thermoplastic elastomer composition and the gas. It is necessary to make sure that it does not end up.

  After the measurement in the foaming control step, the opening / closing valve (10) is switched to the closed state, and injection into the mold (3) is performed by the injection plunger (11). A method of inducing the generation of cell nuclei by slightly reducing the pressure in the injection device (2) by sucking back the injection plunger (11) before performing post-metering injection is also suitably used.

  The high-pressure gas injected from the gas cylinder (18) or the metering pump (5) through the pressure control valve (19) is filled in the mold (3) immediately before being injected at a predetermined pressure. For example, when nitrogen is used as the high-pressure gas, the pressure is preferably equal to or higher than the critical pressure of carbon dioxide used as the blowing agent.

  By filling the mold (3) with high-pressure gas in advance, the molten urethane-based thermoplastic elastomer composition injected into the mold (3) is filled into the mold (3) without foaming. The surface appearance is good.

  Further, in the foam control step, a molten urethane-based thermoplastic elastomer composition in which a urethane-based thermoplastic elastomer and carbon dioxide are in a compatible state is injected into the mold (3) filled with the high-pressure gas. After injection, a rapid pressure drop is caused in the mold (3) by rapidly removing the high-pressure gas filled in the mold (3). By this step, the gas impregnated in the urethane-based thermoplastic elastomer composition becomes supersaturated and a large number of cell nuclei are generated.

  As a method of causing a rapid pressure drop in the mold (3), a molten urethane-based thermoplastic elastomer composition in which a compatible state of urethane-based thermoplastic elastomer and carbon dioxide is formed in the mold (3) is injected. Thereafter, a method in which a part or all of the core is retracted, the capacity in the mold (3) is rapidly increased, and a rapid pressure drop in the mold (3) is preferably used. Such a pressure reduction range is preferably 7.4 to 30 MPa, and more preferably 7.4 to 25 MPa.

  The expansion ratio can be appropriately controlled by the mold (3) temperature, the mold (3) internal pressure, or the core retraction amount in the mold (3), and a urethane-based thermoplastic elastomer having a desired expansion ratio. A composition foam is obtained.

  Even if each of these methods for controlling foaming while reducing the pressure in the mold is sufficient, a sufficient foaming control effect can be obtained, but there is no problem in using the two methods in combination.

  In the method for producing a foamed urethane-based thermoplastic elastomer composition by injection molding according to the present invention, a predetermined amount of carbon dioxide as a foaming agent may be added quantitatively and stably to a melted urethane-based thermoplastic elastomer composition. Because it is possible, carbon dioxide is added to the molten urethane-based thermoplastic elastomer composition in the resin plasticizing cylinder (1) and kneaded thoroughly, and then weighed and injection molded into the injection device (2). Therefore, it is easy to form a compatible molten urethane-based thermoplastic elastomer composition and maintain the compatible state of the molten urethane-based thermoplastic elastomer composition, so that the surface appearance of the foam is improved. In addition, a urethane-based thermoplastic elastomer composition foam from a low foam product to a high foam product can be produced with a constant quality.

  In addition, in order to obtain such a urethane-based thermoplastic elastomer composition foam of the present invention, it is preferable to use a production apparatus to which the same conditions as the production method described above are applied.

(Example of production method for urethane-based thermoplastic elastomer foam laminate)
In the present invention, it is also possible to produce a urethane-based thermoplastic elastomer foam laminate in which a urethane-based thermoplastic elastomer and a thermoplastic resin structure are laminated.

  In the present specification, the thermoplastic resin structure means all molded products molded by other known resin molding methods such as injection molding, extrusion molding, blow molding, press molding, rotational molding, injection compression molding, and the like. Meaning, foams, fiber reinforced foams, long fiber laminates, non-foamed injection molded products, non-foamed extrusion molded products and the like are included.

  Examples of a method for producing such a urethane-based thermoplastic elastomer foam include the following methods.

Before injecting the molten urethane-based thermoplastic elastomer composition into the mold (3), the mold is opened to mount the thermoplastic resin structure in the mold (3) cavity. After mounting, after closing the mold, the mold (3) is filled with high-pressure gas as necessary, and then the thermoplastic resin is produced by the above-described method for producing the urethane-based thermoplastic elastomer foam of the present invention. A urethane-based thermoplastic elastomer foam is laminated on the resin structure to produce a urethane-based thermoplastic elastomer foam laminate.

  In addition to the method of opening and closing the mold and mounting the thermoplastic resin structure in the mold (3) cavity, the thermoplastic resin structure is moved in the mold (3) by a double injection molding machine or the like. After molding, the urethane thermoplastic elastomer foam is laminated on the thermoplastic resin structure by the method for producing the urethane thermoplastic elastomer foam of the present invention described above to produce a urethane thermoplastic elastomer foam laminate. This method is also preferably used.

  An example of the embodiment by extrusion molding of the present invention will be described below with reference to the drawings. In FIG. 6, (4) is a liquefied carbon dioxide cylinder, (5) is a metering pump, (6) is a refrigerant circulator, (7) is a pressure holding valve, (8) is a heater, (9) is a flow meter, (21 ) Is the first extruder, (22) is the second extruder, (23) is the connecting part, (24) is the die, (25) is the foam, (26) is the hopper, (27) is the screw, (28 ) Is a cooling device.

  The urethane-based thermoplastic elastomer is charged into the first extruder (21) having a line for adding a foaming agent to the molten urethane-based thermoplastic elastomer constituting the inlet side of the continuous plasticizing apparatus, and the carbon dioxide is heated and melted. Carbon is added to form a molten urethane-based thermoplastic elastomer composition in a compatible state of the urethane-based thermoplastic elastomer and the foaming agent.

  As a method for adding a foaming agent to the molten urethane-based thermoplastic elastomer in the continuous plasticizer, for example, a method in which carbon dioxide in a gaseous state is injected directly or in a pressurized state, carbon dioxide in a liquid state is a plunger. A method of adding with a pump or the like can be mentioned. Carbon dioxide is injected from a liquefied carbon dioxide cylinder (4) or the like into a metering pump (5) while maintaining a liquid state, and the discharge pressure of the metering pump (5) is reduced to carbon dioxide. After controlling and discharging with a pressure-holding valve (7) so as to be a constant pressure within the range of the critical pressure (7.4 MPa) to 40 MPa of carbon, the temperature is raised above the critical temperature (31 ° C.) of carbon dioxide and supercritical dioxide A method of adding carbon to a molten urethane-based thermoplastic elastomer is preferably used.

  The molten urethane-based thermoplastic elastomer composition is then transferred to a second extruder (22) that constitutes the outlet side of the continuous plasticizer, and the temperature is gradually lowered to the optimum temperature condition for foaming. At this time, the pressure and temperature conditions up to the tip of the second extruder (22) are preferably in a supercritical state at or above the critical pressure of carbon dioxide and above the critical temperature.

  Preferably, an adapter having a mixing portion is provided at the connecting portion (23) between the first extruder (21) and the second extruder (22). As a result, mixing of the molten urethane-based thermoplastic elastomer and carbon dioxide further proceeds, and it becomes easy to form a compatible state of the urethane-based thermoplastic elastomer and carbon dioxide, and the temperature is controlled by the adapter, thereby the molten urethane. It becomes easy to cool the thermoplastic elastomer composition to a viscosity suitable for subsequent foaming.

  The type of the adapter having the mixing part is not particularly limited, but an adapter incorporating a static mixer capable of kneading and cooling the molten urethane-based thermoplastic elastomer composition is preferably used.

  However, if the melted urethane-based thermoplastic elastomer composition can be sufficiently formed in the first extruder (21) and can be cooled to the optimum foaming temperature, the continuous plasticizer is used as the second extruder. It is not necessary to use a tandem type foaming extruder using (22), and only one extruder may be used.

  Next, the molten urethane-based thermoplastic elastomer composition is transferred to a die (24) connected to the tip of the continuous plasticizer set at the optimum foaming temperature, and foaming is started by reducing the pressure.

  In the method for producing a urethane-based thermoplastic elastomer foam laminate by extrusion molding according to the present invention, in the gas dissolving step for forming a compatible state between the urethane-based thermoplastic elastomer and carbon dioxide, the inlet side of the continuous plasticizing apparatus is After the urethane-based thermoplastic elastomer is heated and melted in the first extruder (21), carbon dioxide is added to the molten urethane-based thermoplastic elastomer and mixed uniformly.

  In the cooling step, the molten urethane-based thermoplastic elastomer composition is cooled at the outlet side of the continuous plasticizer and adjusted so as to have a viscosity suitable for foaming.

  In the foaming control step, the molten urethane-based thermoplastic elastomer composition was reduced to a pressure below the critical pressure of carbon dioxide in the die (24), so that the carbon dioxide became supersaturated and became supersaturated. A large number of cell nuclei are generated in the molten urethane-based thermoplastic elastomer composition. Furthermore, the foam (25) is rapidly cooled at a temperature not higher than the crystallization temperature of the urethane-based thermoplastic elastomer to control the growth of the generated cells and to a desired foaming ratio.

  Among these, at least the gas dissolving step and the cooling step can be performed in the following manner, for example, according to the method described in the claims and each example described in JP-A-8-11190.

  As shown in FIG. 6, the urethane thermoplastic elastomer is added from the hopper (26) into the first extruder (21) constituting the inlet side of the continuous plasticizer, and the plasticizing temperature of the urethane thermoplastic elastomer is increased. Melts at the above temperature. The temperature at this time is generally 100 ° C. or higher, more preferably 110 ° C. or higher, further preferably 150 to 240 ° C., and particularly preferably 160 to 230 ° C. Carbon dioxide is injected from the liquefied carbon dioxide cylinder (4) into the metering pump (5), where the pressure is increased, and the pressure-controlled carbon dioxide is melted in the first extruder (21) in the urethane-based thermoplastic elastomer. Add to.

  At this time, the carbon dioxide existing in the first extruder (21) greatly enhances the solution diffusion with respect to the molten urethane-based thermoplastic elastomer, and can penetrate into the urethane-based thermoplastic elastomer in a short time. For this reason, it is preferable that the system is maintained at a critical pressure or higher and a critical temperature or higher of the carbon dioxide.

  Further, the carbon dioxide added to the first extruder (21) may be added after the temperature is increased and the pressure becomes supercritical before being added to the first extruder (21).

  The urethane-based thermoplastic elastomer and carbon dioxide melted in the first extruder (21) are kneaded by the screw (27) to form a compatible state of the urethane-based thermoplastic elastomer and carbon dioxide.

In the post-compatibility cooling step, by controlling the temperature at the tip of the second extruder (22) that constitutes the outlet side of the continuous plasticizer, the molten urethane-based thermoplastic elastomer composition is transformed into the molten urethane-based thermoplastic elastomer composition. It is cooled to a temperature not lower than the plasticizing temperature, not higher than the plasticizing temperature of the molten urethane-based thermoplastic elastomer composition and not higher than 50 ° C., and not higher than the melting temperature in the gas dissolving step. As temperature at this time, 50-230 degreeC, Preferably it is 80-22
It cools to 0 degreeC and more than the plasticization temperature of a molten urethane type thermoplastic elastomer composition, and it adjusts so that it may become a viscosity suitable for subsequent foaming.

  An example of a method for continuously producing a foamed sheet by the method for producing a urethane-based thermoplastic elastomer composition foam of the present invention will be described in more detail below with reference to the drawings. In addition, although the example using a circular die is illustrated here, T-die, such as a coat hanger die and a fish tail die, can also be used.

  In FIG. 7, (4) is a liquefied carbon dioxide cylinder, (5) is a metering pump, (6) is a refrigerant circulator, (7) is a pressure holding valve, (8) is a heater, (9) is a flow meter, (21 ) Is the first extruder, (22) is the second extruder, (23) is the connecting part, (26) is the hopper, (27) is the screw, (29) is the circular die, (30) is the foam sheet, ( 31) is a water-cooled mandrel.

  In FIG. 7, in the gas dissolving step, 100 parts by mass of the urethane-based thermoplastic elastomer composition is added from the hopper (26) into the first extruder (21) constituting the inlet side of the continuous plasticizer, and heated and melted. Let Carbon dioxide is temperature-controlled from a liquefied carbon dioxide cylinder (4) and injected into a metering pump (5) where the pressure is increased and 0.1-20 parts by mass of pressure-controlled carbon dioxide is added to the first extruder ( 21) is added to the molten urethane-based thermoplastic elastomer composition, and a gas dissolution step is performed.

  At this time, the carbon dioxide existing in the first extruder (21) greatly enhances the solution diffusion with respect to the molten urethane-based thermoplastic elastomer, and can penetrate into the urethane-based thermoplastic elastomer in a short time. Therefore, the inside of the system is preferably maintained at a critical pressure or higher and a critical temperature or higher of the carbon dioxide.

In the case of carbon dioxide, the critical pressure is 7.4 MPa, the critical temperature is 31 ° C., and the first extruder (2
In 1), the pressure is in the range of 7.4 to 40 MPa, preferably 10 to 30 MPa, and the temperature is generally 100 ° C. or higher, more preferably 110 ° C. or higher, further preferably 150 to 300 ° C., particularly preferably 160 to 280. Most preferably, the upper limit value is 230 ° C. or lower.

  Carbon dioxide added to the urethane-based thermoplastic elastomer melted in the first extruder (21) may be added after the temperature is increased and the temperature becomes supercritical before addition.

  The urethane-based thermoplastic elastomer and carbon dioxide melted in the first extruder (21) are kneaded by the screw (27) to form a compatible state of the urethane-based thermoplastic elastomer and carbon dioxide.

  In the cooling step after compatibilization, in order to increase the solubility of carbon dioxide in the urethane-based thermoplastic elastomer, the molten urethane-based thermoplastic elastomer composition is supplied to the second extruder (22) that constitutes the outlet side of the continuous plasticizer. Feed it and lower it to a temperature suitable for foaming.

  The temperature at this time is 110 to 230 ° C., preferably 130 to 220 ° C. and kept at a temperature equal to or higher than the plasticizing temperature of the molten urethane-based thermoplastic elastomer composition, and becomes a viscosity suitable for subsequent foaming. Adjust the temperature in the same way.

The cooling process using the second extruder (22) is a process for reasonably approaching a temperature condition suitable for foaming. By sufficiently cooling in this step, it becomes easy to produce a continuous and stable urethane-based thermoplastic elastomer foam. However, when using a device capable of sufficiently cooling the molten urethane-based thermoplastic elastomer composition to a temperature suitable for foaming with only the first extruder (21) as the continuous plasticizer, the outlet side of the continuous plasticizer As a result, it is not necessary to connect the second extruder (22), and it is also possible to produce a foam with a single extruder.

  Further, in order to improve the dissolved state of carbon dioxide in the molten urethane-based thermoplastic elastomer composition, a kneading part such as a static mixer is connected to the connecting part (23) of the first extruder (21) and the second extruder (22). Is more preferably connected.

  Next, in the foaming control step, the molten urethane-based thermoplastic elastomer composition is transferred to a circular die (29) connected to the outlet side of the continuous plasticizer set at the optimum foaming temperature, and foaming is started. The pressure is reduced under the conditions controlled at the outlet of the circular die (29) to bring the carbon dioxide into a supersaturated state.

  The molten urethane-based thermoplastic elastomer composition in a supersaturated state becomes thermally unstable and generates a large number of cells. It is known that the glass transition temperature of a resin containing gas generally decreases in proportion to the amount of gas impregnation, but the temperature in the circular die (29) is a molten urethane-based thermoplastic elastomer. It is preferable that it is more than the glass transition temperature of a composition.

  The molten urethane-based thermoplastic elastomer composition that has started foaming is extruded from the outlet of the circular die (29).

  The molten urethane-based thermoplastic elastomer composition extruded from the circular die (29) starts foaming at the same time as discharging, but is covered with a water-cooled mandrel (31) installed at the tip of the circular die (29). The foam shaped into a cylindrical shape proceeds while being cooled along the water-cooled mandrel (31), and is then cut by a cutter blade to obtain a urethane-based thermoplastic elastomer foam sheet (30).

  In the present invention, it is necessary to prevent the molten urethane-based thermoplastic elastomer composition from being separated into the urethane-based thermoplastic elastomer composition and carbon dioxide until the gas dissolution step and the cooling step are completed. However, for that purpose, it is preferable to maintain a pressure higher than the critical pressure of carbon dioxide.

  In the method for producing a foamed urethane-based thermoplastic elastomer composition by extrusion molding according to the present invention, the molten urethane-based thermoplastic elastomer composition in the first extruder (21) constituting the inlet side of the continuous plasticizing apparatus is subjected to carbon dioxide. After carbon is added and kneaded sufficiently, a urethane thermoplastic elastomer composition and carbon dioxide are formed in a compatible state, and the temperature of the molten urethane thermoplastic elastomer composition is lowered on the outlet side of the continuous plasticizer. The foaming is started by the pressure drop, and the foaming ratio is controlled by the cooling device (11), so that the wide range from the low-magnification foam of about 1 to 4 times to the high-magnification foam of about 4 to 50 times. A urethane-based thermoplastic elastomer composition foam can be produced continuously with a constant quality.

  In addition, in order to obtain such a urethane-based thermoplastic elastomer composition foam of the present invention, it is preferable to use a production apparatus to which the same conditions as the production method described above are applied.

  Moreover, when employ | adopting injection molding, it can foam also with a urethane type thermoplastic elastomer (A-1) independent. Moreover, also when mixing a urethane type thermoplastic elastomer (A-1) and another thermoplastic elastomer (A-2), the ratio can be arbitrarily selected according to the use and purpose of use.

[Usage of urethane-based thermoplastic elastomer composition foam]
The urethane-based thermoplastic elastomer composition foam obtained by the method for producing a urethane-based thermoplastic elastomer composition foam of the present invention is not particularly limited in the shape of a product that can be produced, and is used for various molded products. be able to.

The urethane-based thermoplastic elastomer composition foam includes, for example, an instrument panel skin, a door skin, an instrument panel skin and a door foam foam, a door trim, a pillar, a console box, a steering wheel, a gear lever, Air box, dashboard, replaceable seat, differential garnish, curl top garnish, ceiling material, weatherstrip sponge, etc .;
Automotive parts such as trunk room lining, engine room lining, bumper, fender, bonnet surface, side shield, cushions;
Two-wheel parts such as steering wheel, inside of helmet, seat, surface layer of racing suit;
Mouse, keyboard, OA housing, headphones, calculator, telephone handset, PHS, mobile phone and other OA equipment parts and products such as mouse pads and desk mats; MO, CD-ROM, DVD, etc. Packing agent for media desk,
Miscellaneous goods such as system notebooks, wallets, notebooks, files, bags, toilet seats, pencils, ballpoint pens, fountain pens, carpets, sandals, clogs, slippers, kitchen knives, heel grips, shoe soles, sandals, etc .;
Electrical parts such as wire coverings, connectors, caps and plugs;
Civil engineering materials such as water plates, seal sponges, ski mats, noise barriers;
Leisure equipment such as golf club grips, golf balls, baseball bat grips, tennis racket grips, swimming fins, underwater glasses;
Sanitary (paper diapers), porous film sheets, synthetic leather, agricultural film,
Examples include vibration-damping and sound-proof sheets, gaskets, waterproof cloth, garden hoses, belts and other miscellaneous goods, industrial packing, and the like.

[Example]
EXAMPLES The present invention will be described below with reference to examples, but the contents of the present invention are not limited to these examples.

(Physical property evaluation method)
The physical properties described in the examples and comparative examples were evaluated according to the following methods.

1) Surface appearance When the surface of the foamed sheet is uniform and uniform by visual observation, B is observed when cell roughness is observed on the surface due to bubble breakage, and there is a blistering blister. The case was C and A was acceptable.

2) Foaming ratio A urethane-based thermoplastic elastomer foam sheet or foam was continuously produced, and three samples were obtained every 10 minutes. The obtained sample was processed into a size of 30 mm × 30 mm, and the density was measured using an electron density meter. The ratio to the density of the urethane-based thermoplastic elastomer as a raw material was calculated from the measured values at three points, and the value rounded to the second decimal place was taken as the expansion ratio.

3) a case where flexibility sample touch is soft like a rubber sponge A, a case as hard non-foam resin is C, the extent therebetween A ^- Pass the above ^-, B, B ^- and then, A It was.

4) Heat resistance The 5% weight loss temperature by TG-DTA was measured, 280 degreeC or more was set to A, 260 degreeC or more, less than 280 degreeC was set to B, less than 260 degreeC was set to C, and B or more was set to pass.

5) Average cell diameter A urethane-based thermoplastic elastomer foam sheet or foam was continuously produced, and three samples were obtained every 10 minutes. The cross sections of the three samples were taken with a scanning electron microscope.

Each cross-sectional photograph was subjected to image processing, the equivalent circle diameter was measured for a cell in a 500 μm square, and the average equivalent circle diameter was calculated. The average value of the average equivalent circle diameter of the three points was defined as the average cell diameter.

6) Uniformity of the cell For each of the three samples, the maximum equivalent circle diameter in the foamed sheet cross-section photograph (500 μm square) taken with a scanning electron microscope is 1.5 times or less the average equivalent circle diameter, and The case where the average equivalent circle diameter of the three points is within 2/3 to 1.5 times the average cell diameter is A. Similarly, the maximum equivalent circle diameter is not more than twice the average equivalent circle diameter, and three points. The case where the average equivalent circle diameter was within 1/2 to 2 times the average cell diameter was defined as B, and the case exceeding the range of B was defined as C, and B or more was regarded as acceptable.

7) Quality Stability In the above evaluation, the surface appearance and cell uniformity were both A, A was B or more, B was C, and B or more was acceptable. An object A with no cell roughness, a slight B, and a slight C were used.

8) Permanent elongation Permanent elongation after holding for 10 minutes at an elongation rate of 200% in accordance with JISK6301-3 and 10 minutes after load removal. Permanent elongation is 50% or less, preferably 0.5 to 40%, more preferably 0.5 to 30%.

9) Gel content (chloroform insoluble matter)
A sample of the urethane-based thermoplastic foam composition is cut into 0.5 mm × 0.5 mm × 0.5 mm strips, and then 500 mg of the obtained strips are weighed into a 300 mesh wire mesh (100 mm × 100 mm). Wrap the sample, seal with staples, and reweigh. The sampled wire mesh is placed in a 300 ml flask, and about 200 ml of chloroform is added thereto. Heat and dissolve for about 5 hours while stirring gently on a hot plate with a stirrer. The wire mesh is removed from the flask and dried in a vacuum dryer (100 ° C.) for about 5 hours. Return to room temperature and weigh the wire mesh with sample.

Gel fraction = {insoluble TPU mass / sample mass} × 100
The usual gel fraction is 10 to 98 parts by mass, preferably 20 to 98 parts by mass.

  A small gel fraction indicates that there is a large amount of chloroform soluble matter, which is considered to be a phenomenon caused by the presence of oligomeric regions and low molecular weight compounds in the TPU composition caused by thermal decomposition, etc., which is not desirable. .

10) Bulk density It measured according to the underwater substitution method of JIS K7112.

[Example 1]
In Example 1, the apparatus shown in FIG. 1 described herein was used. The carbon dioxide addition part was provided near the center of the resin plasticizing cylinder (1). Peresen 2103-90AEL (trade name, manufactured by Dow Chemical Co., Ltd., dried for 4 hours at 110 ° C. Melt flow rate (ASTMD-1238-65T, 190 ° C, 2.16kg load) as urethane thermoplastic elastomer 0.7 g / 10 min, melting temperature 166 ° C. by DSC measurement, crystallization heat 11.6 J / g, content of allophanate group measured by back titration using amine decomposition method is 0.095 mmol / g) (hereinafter “TPU”) -1 ").) Was used.

  The urethane-based thermoplastic elastomer was added from the hopper (16) to the resin plasticizing cylinder (1) and melted by heating at 230 ° C.

Carbon dioxide was extracted directly from the liquid phase part using a siphon type liquefied carbon dioxide cylinder (4). The flow path from the liquefied carbon dioxide cylinder (4) to the plunger pump (5) is cooled with an ethylene glycol aqueous solution adjusted to −12 ° C. using the refrigerant circulator (6), and the carbon dioxide is plungerd in a liquid state. The pump (5) could be injected. Next, the plunger pump (5) is controlled so that the injected liquid carbon dioxide is 1 part by mass with respect to 100 parts by mass of the urethane-based thermoplastic elastomer, and the discharge pressure of the plunger pump (5) is kept at 30 MPa. It adjusted with the pressure valve (7). Next, the line from the pressure holding valve (7) to the carbon dioxide addition part of the resin plasticizing cylinder (1) is heated with a heater (8) so as to reach 50 ° C., and the carbon dioxide is melted in the resin plasticizing cylinder (1). Was added to the urethane-based thermoplastic elastomer. At this time, the molten resin pressure in the addition portion was 20 MPa. That is, carbon dioxide immediately before being dissolved in the molten urethane-based thermoplastic elastomer is supercritical carbon dioxide having a temperature of 50 ° C. or higher and a pressure of 20 MPa.

  In this way, carbon dioxide was added to the completely melted urethane thermoplastic elastomer. An injection apparatus in which carbon dioxide and molten urethane thermoplastic elastomer are kneaded and dissolved in the resin plasticizing cylinder (1), and the temperature of the molten urethane thermoplastic elastomer composition is gradually cooled to 160 ° C. and set to 160 ° C. After weighing to (2), it was injected into the mold (3) set at 40 ° C. At this time, the mold (3) immediately before being injected was filled with nitrogen gas under a pressure of 8 MPa. After the injection is finished, the cavity is sized to be 60 × 60 × 2 (thickness) mm in order to remove the nitrogen gas filled in the mold (3) in 1 second and further increase the expansion ratio to about 2 times. The core of the mold (3) was retracted 2 mm to obtain a flat plate (60 mm × 60 mm × 4 mm) which is a urethane-based thermoplastic elastomer foam.

  The evaluation results of the obtained foam are shown in Table 1. The foam was excellent in flexibility, heat resistance and surface appearance.

[Example 2]
In Example 1, as a urethane-based thermoplastic elastomer, Pelecene 2355-80AE (trade name, manufactured by Dow Chemical Company, melt flow rate (ASTMD-1238-65T, 190 ° C., 2.16 kg load) 2.7 g / 10 min, crystal Heat of formation 10.8 J / g) (hereinafter sometimes referred to as “TPU-2”) 100 parts by mass, except that 2 parts by mass of liquid carbon dioxide with respect to TPU-2 was used. A foam was obtained in the same manner as the operating procedure.

  The evaluation results of the obtained foam are shown in Table 1. The foam was excellent in flexibility, heat resistance and surface appearance.

[Comparative Examples 1 and 2]
A foam was obtained in the same manner as in Example 1, except that the ratio of the thermoplastic elastomer and carbon dioxide was changed to the ratio shown in Table 1.

  The results of evaluation of the obtained foam are shown in Table 2. It is not preferable in terms of poor surface appearance and a desired expansion ratio, and the foam intended in the present invention cannot be produced.

[Comparative Example 3]
In Example 1, 2 parts by mass of azodicarbonamide was used in place of carbon dioxide as a foaming agent, and gas was generated by decomposing azodicarbonamide, so that the cylinder temperature was set to 200 ° C. In the same manner as in Example 1, a foam was obtained.

  The results of evaluation of the obtained foam are shown in Table 2. It was a foam having a nonuniform cell diameter and a poor surface appearance, and was not a foam intended by the present invention.

[Comparative Example 4]
In Example 2, instead of carbon dioxide as a blowing agent, 2 parts by mass of azodicarbonamide was used, and gas was generated by decomposing azodicarbonamide, so that the cylinder temperature was set to 200 ° C. Example 2 In the same manner, a foam was obtained.

  The results of evaluation of the obtained foam are shown in Table 2. It was a foam having a nonuniform cell diameter and a poor surface appearance, and was not a foam intended by the present invention.

[Example 3]
As a urethane-based thermoplastic elastomer, Pelecene 2363-80AE (trade name, manufactured by Dow Chemical Co., Ltd., melt flow rate (ASTMD-1238-65T, 190 ° C., 2.16 kg load) 4.1 g / 10 min, crystallization heat 7.3 J / G) (hereinafter sometimes referred to as “TPU-3”), liquid foam was used in the same procedure as in Example 1 except that 3 parts by mass of liquid carbon dioxide was used with respect to TPU-3.

  Further, in Example 1, a flat plate (60 mm × 60 mm × 60 mm) which is a urethane-based thermoplastic elastomer foam according to Example 1 except that the retraction amount of the core of the mold (3) is 10 mm and the set magnification is about 6 times. 12 mm).

  The evaluation results of the obtained foam are shown in Table 1. The foam was excellent in flexibility, heat resistance and surface appearance.

[Example 4]
In Example 1, as a urethane-based thermoplastic elastomer, Pelecene 2102-80A (trade name, manufactured by Dow Chemical Co., Ltd., melt flow rate (ASTMD-1238-65T, 190 ° C., 2.16 kg load) 1.6 g / 10 min, crystal Heat of formation 9.7 J / g) (hereinafter sometimes referred to as “TPU-4”) 1
A foam was obtained according to the operation procedure of Example 1 except that 00 parts by mass and 2 parts by mass of liquid carbon dioxide were used with respect to TPU-4.

  Further, in Example 1, a flat plate (60 mm × 60 mm × 60 mm) which is a urethane-based thermoplastic elastomer foam according to Example 1 except that the retraction amount of the core of the mold (3) is 4 mm and the set magnification is 3 times. 6 mm).

  The evaluation results of the obtained foam are shown in Table 1. The foam was excellent in flexibility, heat resistance and surface appearance.

[Comparative Example 5]
In Example 3, a flat plate of a foam was obtained in the same manner as in Example 3 except that 3 parts by mass of butane gas was used as a foaming agent (60 mm × 60 mm × 10 mm).

  The results of evaluation of the obtained foam are shown in Table 2. The foam has good flexibility but poor heat resistance, and was not a foam having the performance intended by the present invention.

[Comparative Example 6]
In Example 4, a flat plate of a foam was obtained in the same manner as in Example 4 except that 3 parts by mass of butane gas was used as a foaming agent (60 mm × 60 mm × 10 mm).

  The results of evaluation of the obtained foam are shown in Table 2. The foam had good heat resistance but poor flexibility, and was not a foam having the performance intended by the present invention.

[Comparative Example 7]
In Example 2, a flat plate of foam was obtained in the same manner as in Example 2 except that 3 parts by mass of butane gas was used as the foaming agent (60 mm × 60 mm × 10 mm).

  The results of evaluation of the obtained foam are shown in Table 2. The foam had good heat resistance but poor flexibility, and was not a foam having the performance intended by the present invention.

[Examples 5 to 7]
Pelecene 2103-90AEL and Pelecene 235 having melt flow rates (ASTMD-1238-65T, 190 ° C., 2.16 kg load) of 0.7 g / 10 min and 2.7 g / 10 min, respectively.
A foam was obtained in the same manner as in Example 2 except that 5-80AE was used in the amount shown in Table 1, and 5 mass parts of carbon dioxide was used.

  The evaluation results of the obtained foam are shown in Table 1. The foam was excellent in flexibility, heat resistance and surface appearance.

[Examples 8 to 16]
For production of the foam, the apparatus shown in FIG. 7 described in the specification was used. As a continuous plasticizer, a tandem type extruder having a first extruder (21) with a screw diameter of 50 mm and a second extruder (22) with a screw diameter of 65 mm is used, and is attached to the tip of the second extruder (22). Connected a circular die (29) having an exit gap of 0.5 mm and a diameter of 80 mm, and a water-cooled mandrel (31) having a diameter of 200 mm was used as a cooling device. The rotation speed of the first extruder (21) was 40 rpm. The extrusion amount of the thermoplastic resin composition was about 10 kg / Hr.

  The carbon dioxide addition part was provided near the center of the first extruder (21).

  The same TPU-1 as in Example 1 was used as the urethane-based thermoplastic elastomer, and the composition was added from the hopper (26) to the first extruder (21) and melted by heating at 220 ° C.

Carbon dioxide was extracted directly from the liquid phase part using a siphon type liquefied carbon dioxide cylinder (4). The flow path from the liquefied carbon dioxide cylinder (4) to the plunger pump (5) is cooled with an ethylene glycol aqueous solution adjusted to −12 ° C. using the refrigerant circulator (6), and the carbon dioxide is plungerd in a liquid state. The pump (3) could be injected. Next, the plunger pump (3) was controlled so that the injected liquid carbon dioxide was 1 kg / hour, and the discharge pressure of the plunger pump (3) was adjusted by the pressure holding valve (7) so as to be 30 MPa.
At this time, the volumetric efficiency of the plunger pump (3) was constant at 65%. Next, the line from the pressure holding valve (7) to the carbon dioxide addition part of the first extruder (21) is heated with a heater (8) so as to reach 50 ° C., and the carbon dioxide is melted in the first extruder (21). Was added to the urethane-based thermoplastic elastomer. At this time, the molten resin pressure in the addition portion was 20 MPa. That is, the carbon dioxide immediately before being dissolved in the molten urethane-based thermoplastic elastomer is a supercritical carbon dioxide having a temperature of 50 ° C. or higher and a pressure of 20 MPa.

  In this way, while measuring the carbon dioxide in the supercritical state with the flow meter (9), in the first extruder (21) at a ratio of 1 part by mass with respect to 100 parts by mass of the molten urethane-based thermoplastic elastomer. The mixture was added and mixed uniformly with the screw (27). Next, this molten urethane-based thermoplastic elastomer was sent to the second extruder (22), the resin temperature was adjusted to 200 ° C., and extruded from the circular die (29) at an extrusion rate of 10 kg / hour. The die pressure at this time was 8 MPa. The extruded urethane-based thermoplastic elastomer is foamed at the same time as it comes out of the circular die (29), and is put on a water-cooled mandrel (31) installed at the tip of the circular die (29). The urethane-based thermoplastic elastomer foam formed into a cylindrical shape is allowed to proceed while cooling along the mandrel (31), and then cut with a cutter blade to produce a urethane-based thermoplastic elastomer foam sheet (30). did. The obtained urethane-based thermoplastic elastomer foam sheet (30) had a beautiful appearance with a width of 63 mm and a thickness of 1.5 mm.

  The evaluation results of the obtained foamed sheet are shown in Table 1, Table 3, and Table 4. A foam having excellent flexibility, heat resistance and surface appearance was obtained.

[Comparative Example 8]
In Example 8, a foam was obtained in the same manner as in Example 8 except that the ratio of the thermoplastic elastomer and carbon dioxide was changed to the ratio shown in Table 2.

  The results of evaluation of the obtained foam are shown in Table 2. It was not preferable in terms of not a desired expansion ratio, poor flexibility, and poor quality stability, and the foam intended in the present invention could not be produced.

[Reference Example 1]
Example of foaming of TPU sheet by batch method.

  A sheet having a thickness of 1 mm and a size of 100 mm × 100 mm was preliminarily formed from Pelecene 2103-90AEL pellets using a hot press. This sheet was put into a 300 cc autoclave, supercritical carbon dioxide increased to a temperature of 40 ° C. and a pressure of 15 MP was introduced, and maintained for 3 hours to impregnate carbon dioxide in the polymer. After that, the pressure was released and a foam sheet was obtained. When the foamed TPU sheet was measured by DSC, the heat of fusion and the heat of crystallization were equal to or slightly lower than the TPU pellets before foaming.

  In addition, it is considered that when supercritical CO 2 foaming of TPU is carried out in an extruder, the molecular temperature is easily oriented and the heart segments are easily aggregated, so that the melting temperature Tm is increased. On the other hand, it is considered that this effect is small because the batch method foams in the isotropic direction.

FIG. 1 is a schematic configuration diagram showing an example of a method for producing a urethane-based thermoplastic elastomer foam of the present invention. FIG. 2 is a schematic configuration diagram showing an example of a method for producing the urethane-based thermoplastic elastomer foam of the present invention. FIG. 3 is a schematic configuration diagram showing an example of a method for producing the urethane-based thermoplastic elastomer foam of the present invention. FIG. 4 is a schematic configuration diagram showing an example of a method for producing the urethane-based thermoplastic elastomer foam of the present invention. FIG. 5 is a schematic configuration diagram showing an example of a method for producing the urethane-based thermoplastic elastomer foam of the present invention. FIG. 6 is a schematic configuration diagram showing an example of a method for producing the urethane-based thermoplastic elastomer foam of the present invention. FIG. 7 is a schematic configuration diagram showing an example of a method for continuously producing a foamed sheet by the method for producing a urethane-based thermoplastic elastomer foam of the present invention.

Explanation of symbols

(1) Resin plasticizing cylinder (2) Injection device (3) Mold (4) Liquefied carbon dioxide cylinder (5) Metering pump (6) Refrigerant circulator (7) Holding valve (8) Heater (9) Flow meter ( 10) Open / close valve (11) Injection plunger (12) Adapter (13) Resin accumulator plunger (14) Resin accumulator device (15) Inline screw type injection molding machine (16) Hopper (17) Screw (18) Gas cylinder (19 ) Pressure control valve (20) Open / close valve (21) First extruder (22) Second extruder (23) Connecting part (24) Die (25) Foam (26) Hopper (27) Screw (28) Cooling device (29) Circular dice (30) Foam sheet (31) Water-cooled mandrel

Claims (17)

A foam comprising a thermoplastic polyurethane resin-containing composition containing 20% by mass or more of a thermoplastic polyurethane resin, the average cell diameter of the foam being 0.1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³ ,
Permanent elongation is 1% or more and 100% or less,
A urethane-based thermoplastic elastomer composition foam having a bulk density of 0.03 to 1.10 g / cm ³ . The melting point (T _m1 ) of the urethane-based thermoplastic elastomer composition foam and the melting point (T _m2 ) of the _unfoamed product are represented by the following formula (1):
T _m1 -T _m2 ≧ 5 ℃ (1)
The urethane-based thermoplastic elastomer composition foam according to claim 1, wherein:   The urethane-based thermoplastic elastomer composition foam according to claim 1 or 2, wherein the urethane-based thermoplastic elastomer composition foam contains 10% by mass or more of chloroform-insoluble matter. The urethane-based thermoplastic elastomer composition foam has a residue after extraction with chloroform of 20% by mass or more,
The urethane-based thermoplastic elastomer composition foam according to any one of claims 1 to 3, wherein a 5% weight reduction temperature of the residue after extraction with chloroform is 180 ° C or higher. It consists of a urethane-based thermoplastic elastomer (A-1) and other thermoplastic elastomers (A-2), and the mass ratio (A-1 / A-2) of (A-1) to (A-2) is 20 /. 80 to 99/1 in a molten urethane-based thermoplastic elastomer composition (A), 0.1 to 30 parts by mass of carbon dioxide (100 parts by mass of carbon dioxide (100 parts by mass of the urethane-based thermoplastic elastomer composition (A)) A step of adding and mixing (B) to form a molten urethane-based thermoplastic elastomer composition (C) in a mixed state of the urethane-based thermoplastic elastomer composition (A) and carbon dioxide (B) (gas dissolution step) When,
A process for reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling process), and a method for producing a urethane-based thermoplastic elastomer composition foam. 0.1 to 30 parts by mass of carbon dioxide (B) is added to and mixed with 100 parts by mass of the urethane-based thermoplastic elastomer composition (A) in a molten state, and the urethane-based thermoplastic elastomer composition (A) and Forming a molten urethane-based thermoplastic elastomer composition (C) in a mixed state with carbon dioxide (B) (gas dissolving step);
Next, the molten urethane-based thermoplastic elastomer composition (C) obtained through the step of reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step) is reduced to a pressure lower than that of the cooling step. Filling or transferring into a controlled space, generating cell nuclei in the molten urethane-based thermoplastic elastomer composition (C), and then foaming while controlling the expansion ratio (foaming control step). A process for producing a urethane-based thermoplastic elastomer composition foam.   The urethane-based heat according to claim 5 or 6, wherein the urethane-based thermoplastic elastomer composition (A) has a melt flow rate (ASTMD-1238-65T) of 0.5 to 50 g / 10 minutes. A method for producing a foamed plastic elastomer composition. The urethane thermoplastic elastomer composition (A) is a urethane thermoplastic elastomer (A-1) and a melt flow rate (ASTMD-1238-65T) of 0.01 g / 10 min or more and less than 50 g / 10 min. Consisting of some other thermoplastic elastomer (A-2),
The other thermoplastic elastomer (A-2) is contained in an amount of 5 to 60 parts by mass with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). A process for producing a urethane-based thermoplastic elastomer composition foam according to any one of the above.   The temperature of the molten urethane-based thermoplastic elastomer composition in the gas melting step is in the range of 100 to 240 ° C., and the temperature of the molten urethane-based thermoplastic elastomer composition in the cooling step is the temperature in the gas melting step. The method for producing a urethane-based thermoplastic elastomer composition foam according to any one of claims 5 to 8, which is in a range lower by 10 to 100 ° C.   The addition amount of the carbon dioxide (B) is an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). The manufacturing method of the urethane type thermoplastic elastomer composition foam in any one.   The said carbon dioxide (B) is a carbon dioxide (B-1) of a supercritical state, The manufacturing method of the urethane type thermoplastic elastomer composition foam in any one of Claims 5-10 characterized by the above-mentioned.   The method for adding carbon dioxide in the gas dissolving step is to inject the carbon dioxide into a pump for discharging carbon dioxide while maintaining the carbon dioxide in a liquid state, and to set the discharge pressure of carbon dioxide from the pump to the critical pressure of carbon dioxide (7 .4MPa) After discharging carbon dioxide from the pump so as to be a constant pressure within the range of 40MPa, the temperature of the discharged carbon dioxide is raised to a critical temperature of carbon dioxide (31 ° C) or higher and supercritical. The method for producing a urethane-based thermoplastic elastomer composition foam according to any one of claims 5 to 11, wherein carbon dioxide is added to a urethane-based thermoplastic elastomer composition in a molten state.   Amorphous polymer, semi-crystalline polymer, liquid crystal polymer, thermoplastic polymer, wherein the urethane-based thermoplastic elastomer (A-1) contains at least one selected from the group consisting of urethane bonds, urea bonds, thiaurethane bonds and thiourea bonds The method for producing a urethane-based thermoplastic elastomer composition foam according to any one of claims 5 to 12, which is at least one selected from the group consisting of elastomers. It consists of a urethane-based thermoplastic elastomer (A-1) and other thermoplastic elastomers (A-2), and the mass ratio (A-1 / A-2) between (A-1) and (A-2) is as follows. In the molten urethane-based thermoplastic elastomer composition (A) of 20/80 to 99/1, 0.1 to 30 parts by mass of dioxide dioxide with respect to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A). A step of adding carbon (B) and forming a molten urethane-based thermoplastic elastomer composition (C) in a mixed state of the urethane-based thermoplastic elastomer composition (A) and carbon dioxide (B) (gas dissolving step) And a step of reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step),
The average cell diameter is 0.1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³ ,
Permanent elongation is 1% or more and 100% or less,
A urethane-based thermoplastic elastomer composition foam having a bulk density of 0.03 to 1.10 g / cm ³ . 0.1 to 30 parts by mass of carbon dioxide (B) is added to 100 parts by mass of the urethane-based thermoplastic elastomer composition (A) in a molten state, and the urethane-based thermoplastic elastomer composition (A) and carbon dioxide are added. A step (gas dissolving step) of forming a molten urethane-based thermoplastic elastomer composition (C) in a mixed state with (B);
A step of reducing the temperature of the molten urethane-based thermoplastic elastomer composition (C) (cooling step);
The molten urethane-based thermoplastic elastomer composition (C) obtained through the gas melting step and the cooling step is filled or transferred into a space controlled at a lower pressure than the cooling step, and the molten urethane-based heat After generating cell nuclei in the plastic elastomer composition (C), it is obtained through a step of foaming while controlling the expansion ratio (foaming control step).
The average cell diameter is 0.1 μm or more and 1000 μm or less,
The average number of cells is 10 ³ to 10 ¹⁶ cells / cm ³ ,
Permanent elongation is 1% or more and 100% or less,
A urethane-based thermoplastic elastomer composition foam having a bulk density of 0.03 to 1.10 g / cm ³ .   The laminated body containing the urethane type thermoplastic elastomer composition foam in any one of Claims 1-4, 14, and 15.   A molded article comprising the urethane-based thermoplastic elastomer composition foam according to any one of claims 1 to 4, 14, and 15.

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