JP2003159771A - Polyolefin resin foam laminated sheet and method for producing the same - Google Patents

Abstract

(57) [Problem] To provide a polyolefin resin foam laminated sheet which achieves a high expansion ratio, is lightweight, has good surface smoothness, is excellent in impact and heat insulation, and has good secondary workability. SOLUTION: Propylene homopolymerization-resistant or low α-olefin content propylene / α-olefin copolymer 5
A propylene / α-olefin copolymer having a high molecular weight of 0 to 90% by weight and a high α-olefin content of 10 to 50% by weight, MFR of 0.1 to 20 g / 10 min, log MT
(Melt tension)> − 0.97 × log MFR + 1.23,
A foamed polyolefin-based resin laminated sheet comprising a foamed layer made of a polypropylene-based resin composition having a longest relaxation time (τd) of 100 seconds or more and a non-foamed layer in contact with the foamed layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin foam laminated sheet and a method for producing the same, and more particularly to a polypropylene resin foam laminated sheet having a high expansion ratio, light weight and good surface smoothness, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polypropylene is lightweight,
Since it has excellent mechanical properties and chemical resistance, and has a good balance with economic efficiency, various molded products such as sheets, films,
It is widely used in various fields as an injection molded body and the like. Furthermore, in recent years, in the field of seats,
Foamed sheets of polypropylene resin have been used for the purpose of imparting light weight, heat insulation and cushioning properties, and high expansion ratio sheets have come into use. Techniques for increasing the expansion ratio of a polypropylene resin foam sheet include a method using an annular die, a method using various sizing dies (Japanese Patent Laid-Open No. 11-235746, etc.),
Methods such as special cooling at the exit of the die have been proposed. However, these methods have problems such as requiring a special device and deteriorating the surface smoothness. Moreover, when the expansion ratio was lowered to such an extent that the surface smoothness did not become a problem, the expansion ratio was not significantly increased after all. In fields where thermoforming of food containers etc. is required,
Foams obtained by the above method, in preheating during container molding, perforation of the sheet due to overheating, mold transferability is liable to deteriorate due to insufficient heating, and moldable conditions are significantly narrowed There was a problem. In addition, the application is limited because it is extremely difficult to provide a uniform wall thickness and deep drawing.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and achieves a high expansion ratio without using a special device, and is lightweight and has a surface. An object of the present invention is to provide a polyolefin resin foamed laminated sheet having good smoothness, excellent impact resistance and heat insulating properties, and also good secondary processability.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that polypropylene and α-olefin having a specific MFR containing no α-olefin or having a small amount of α-olefin. A composition with a high molecular weight polypropylene-based copolymer having a high content of
By using a polypropylene resin composition having a specific MFR, a relationship between melt tension (MT) and MFR, and a maximum relaxation time (τd) as a foam layer, a high expansion ratio, surface smoothness,
The present invention has been completed by finding that a foamed polyolefin resin laminated sheet having excellent impact resistance and heat insulating properties and having good secondary processability can be obtained.

That is, according to the first aspect of the present invention,
A foam layer comprising at least the following component (a-1) and component (a-2), and a polypropylene resin composition (A) having physical properties of characteristics (A-1) to (A-3): There is provided a polyolefin resin foamed laminated sheet comprising a non-foamed layer in contact with a foamed layer. Component (a-1): Propylene homopolymer having MFR of 10 to 1000 g / 10 min or propylene / α-olefin copolymer having an α-olefin content other than propylene of less than 1% by weight 50 to 90% by weight Component (a) -2): Weight average molecular weight of 500,000 to 1,000
The content of α-olefin other than propylene is 1 to 15
Wt% propylene / α-olefin copolymer 10-
50 wt% Characteristic (A-1): MFR is 0.1 to 20 g / 10 minutes Characteristic (A-2): Melt tension (MT) and MFR satisfy the following relationship. logMT> −0.97 × logMFR + 1.23 Characteristic (A-3): Maximum relaxation time (τd) is 100 seconds or more.

According to the second aspect of the present invention, the non-foaming layer resin material (B) is prepared by blending the non-foaming layer with 10 to 400 parts by weight of a filler based on 100 parts by weight of the polyolefin resin. The polyolefin resin foam laminated sheet according to the first invention is provided.

Further, according to the third invention of the present invention, the polyolefin resin constituting the non-foamed layer is the polypropylene resin composition (A) described in the second invention. There is provided a polyolefin resin foamed laminated sheet.

According to a fourth aspect of the present invention, there is provided a method for producing a foamed laminated sheet having a foamed layer and a non-foamed layer in contact with the foamed layer, the polypropylene resin composition (A). And a non-foaming layer resin material (B) are melt-coextruded in a sheet form from a die,
A method for producing a polyolefin resin foam laminated sheet, comprising the step of forming the foam layer and a non-foam layer in contact with the foam layer.

According to a fifth aspect of the present invention, there is provided a method for producing a foamed laminated sheet having a foamed layer and a non-foamed layer in contact with the foamed layer, which comprises the polypropylene resin composition (A). A mixture of a foaming agent and a non-foaming layer resin material (B) is merged inside the die and then extruded from an annular die to form a tubular laminate in which non-foaming layers are laminated on both sides of the foam layer. Then, the inner surface side of the cylindrical laminated body is brought into contact with the peripheral surface of the cylindrical cooling drum to cool while being drawn, and a sheet-shaped polyolefin resin laminated foam sheet characterized by being cut open is provided. It

According to a sixth aspect of the present invention, the polyolefin resin forming the non-foaming layer resin material (B) is the polypropylene resin composition (A). A method for producing a polyolefin resin foam laminated sheet according to the invention of 4 or 5 is provided.

[0011]

DETAILED DESCRIPTION OF THE INVENTION Foam layer 1. Polypropylene-based resin composition (A) The polypropylene-based resin composition (A) used for the foamed layer of the foamed laminated sheet of the present invention has at least the component (a-1) propylene homopolymer or an α-olefin content other than propylene of 1. It is composed of a propylene / α-olefin copolymer of less than wt% and a propylene / α-olefin copolymer having an α-olefin content other than propylene of component (a-2) of 1 to 15% by weight. As α-olefins other than propylene, α-olefins having 2 to 20 carbon atoms excluding propylene
-Olefins, for example ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-
Heptene, 4-methyl-pentene-1, 4-methyl-hexene-1,4,4-dimethylpentene-1 and the like can be exemplified.

The content of α-olefin in the propylene / α-olefin copolymer as the component (a-1) is less than 1% by weight, preferably less than 0.5% by weight. α
-When the olefin content is 1% by weight or more, the stereoregularity of the produced polymer is lowered, so that the rigidity and heat resistance are deteriorated. As the component (a-1), a propylene homopolymer is preferable from the viewpoint of particle properties of the produced polymer. Here, the α-olefin content is a value measured by ¹³ C-NMR.

The MFR of component (a-1) is 10 to
It is 1000 g / min, preferably 30 to 100 g / min. If the MFR is less than 10 g / min, the viscosity of the material will be too high, and the extrusion characteristics and foaming characteristics will be impaired. When the MFR exceeds 1000 g / min, the compatibility with the component (a-2) is greatly reduced, and thus the foaming property is reduced. In order to control the MFR of the polymer, for example, a method of appropriately controlling the polymerization temperature, the catalyst amount, the supply amount of hydrogen as a molecular weight regulator, and the like can be used. Here, the MFR (melt flow rate) is JIS-K6921-2 (230 ° C., 21.1).
8N load).

The α-olefin in the propylene / α-olefin copolymer of the component (a-2) is the component (a-
The ones listed as the α-olefin in 1) can be used,
It is preferably the same as the α-olefin in the component (a-1). The content of the α-olefin of the component (a-2) is 1 to 15% by weight, preferably 3 to 9% by weight.
Is. When the content of α-olefin is less than 1% by weight,
It becomes difficult to impart a weight average molecular weight of 500,000 to 10,000,000, and if it exceeds 15% by weight, the compatibility with the component (a-1) is reduced and the melt tension of the propylene resin composition (A) is effectively expressed. become unable. Here, the α-olefin content is measured by the above method.

The component (a-2), propylene.α-
The olefin copolymer has a weight average molecular weight of 500,000 to 10
It is, 000,000, preferably 800,000 to 5,000,000. When the weight average molecular weight is less than 500,000, the melt tension improving effect of the propylene-based resin composition is small, and the compatibility with the component (a-1) exceeding 10 million is deteriorated. In order to adjust the weight average molecular weight of the polymer, for example, a method of appropriately adjusting the polymerization temperature, the amount of catalyst, the supply amount of hydrogen as a molecular weight modifier, and the like can be used. Here, the weight average molecular weight is a value measured under the following conditions.

Device: Waters GPC 150C type detector: MIRAN 1A infrared spectrophotometer (measurement wavelength,
3.42 μm) Column: 3 AD806M / S manufactured by Showa Denko KK (The calibration of the column is monodisperse polystyrene (A500, A, manufactured by Tosoh Corporation).
2500, F1, F2, F4, F10, F20, F4
0, F288 0.5 mg / ml solution), and the logarithmic value of the elution volume and the molecular weight were approximated by a quadratic equation. The molecular weight of the sample was converted to polypropylene using the viscosity formula of polystyrene and polypropylene. Here, the coefficient of the viscosity formula of polystyrene is α = 0.723,
logM = −3.967, and polypropylene has α
= 0.707 and logM = -3.616. ) Measurement temperature: 140 ° C. Concentration: 20 mg / 10 mL Injection amount: 0.2 ml Solvent: Orthodichlorobenzene flow rate: 1.0 ml / min

In the polypropylene resin composition (A) used in the present invention, the mixing ratio of the component (a-1) and the component (a-2) is as follows: component (a-1) / component (a-2). Fifty
/ 50 to 90/10 (weight ratio), preferably 70/3
It is 0 to 90/10. When the component (a-1) is less than 50, the extrusion moldability of the polypropylene resin composition (A) deteriorates. When it exceeds 90, the melt tension is lowered and the foaming property is deteriorated.

Further, the polypropylene resin composition (A) used in the present invention has the following characteristics (A-1) to (A-3).
Must be met.

Characteristic (A-1): MFR MFR of the polypropylene resin composition (A) of the present invention
Is 0.1 to 20 g / 10 minutes, preferably 0.5
It is -10 g / 10 minutes. If the MFR is less than 0.1 g / 10 minutes, extrusion moldability becomes difficult. If it exceeds 20 g / 10 minutes, the drawdown property during thermoforming will be significantly reduced. The MFR of the polypropylene resin composition (A) is the component (a-
It depends on the MFR or weight average molecular weight of each of 1) and component (a-2) and their blending ratio.

Characteristic (A-2): Melt tension (MT) and MF
Relationship of R In the polypropylene resin composition (A) of the present invention, it is necessary that the following relationship be established between melt tension (MT) and MFR. logMT> -0.97xlogMFR + 1.23 Preferably, logMT> -0.57xlogMFR + 1.40, and more preferably logMT> -0.27xlogMFR + 1.54.

The upper limit of logMT is not particularly limited, but is −0.08 × logMFR + 1.90> l.
ogMT can be manufactured in existing manufacturing equipment. A polypropylene-based resin composition that does not satisfy the above formula has a low melt tension, is inferior in extrusion characteristics and foaming characteristics, and cannot achieve the object of the present invention. The MT of a polymer is its molecular weight or M
There is a certain correlation with FR, and the higher the molecular weight (the lower the MFR), the higher the MT. A single component cannot exceed a certain MT in relation to the molecular weight, but in the polypropylene resin composition (A) of the present invention, the component (a-1) and the component (a-2) are used. By adjusting the molecular weight (or MFR) and the α-olefin content other than propylene, the molecular weight (or MFR) and compatibility of the polypropylene-based resin composition, particularly of the component (a-2) which becomes a high molecular weight component By fully exerting the effect of increasing MT, an unprecedented relationship between MFR and MT is achieved.

On the other hand, the conventional general-purpose polypropylene resin composition has the left side <the right side in the above formula, and the MFR at the same MT is smaller than that of the polypropylene resin composition (A) used in the present invention. Liquidity deteriorates. That is, in the MFR / MT balance, when the flow rate is low / high MT, the extrusion characteristics are deteriorated, and the shear heat generation becomes remarkable, so that the foaming characteristics are deteriorated. For high flow / low MT,
Although the fluidity is good, the foaming characteristics after the die exit are deteriorated, and phenomena such as cell coalescence, bubble breaking, and foaming in the die frequently occur.

Here, the MT is measured by using a capillograph manufactured by Toyo Seiki Seisakusho, at a cylinder temperature of 190 ° C.
The orifice L / D was 8.1 / 2.095 (mm), the piston speed was 10 mm / min, and the take-up speed was 4.0 m / min. The steady-state tension was taken as the MT value (unit: g).

(3) Characteristic (A-3): Maximum relaxation time (τ
d) The polypropylene resin composition (A) of the present invention has a maximum relaxation time (τd) of 100 seconds or longer, preferably 12 seconds.
0 to 2000 seconds, more preferably 140 to 100
0 seconds. When τd is less than 100 seconds, the contribution of the long relaxation time component becomes small, which causes an obstacle to the processing characteristics.
That is, satisfying τd ≧ 100 seconds is an essential condition in the molding process that requires high melt tension.

The term τd means the time required to return to the random state before deformation through the orientation relaxation in which the deformed molecular chain is relaxed without changing the orientation, which is obtained by stress relaxation measurement.

The τd of the polypropylene resin composition is closely related to the processing characteristics such as foam molding and thermoforming.
It is considered that the larger d is, the better the processing characteristics are. τ
d tends to be lengthened due to the presence of either the high molecular weight component or the branched component, or both,
It does not always coincide with the nonlinearity of extensional viscosity. That is, τd does not specify the non-linearity of elongational viscosity, but the uniform extensibility during elongational deformation.

Here, the measurement of τd follows the following method. Using RMS-800 manufactured by Rheometrics, the relaxation elastic modulus G (t) is measured at a temperature of 200 ° C. and 240 ° C. and a strain of 50 and 100% with a parallel plate having a diameter of 25 mm and a gap of 1.5 mm to prepare a master curve. . Using the obtained G (t), JOURNAL OF POL
YMER SCIENCE, VOL. XL, P443-
Τd is calculated by the method described in 456 (1959).

2. Method for producing polypropylene-based resin composition (A) The catalyst system for obtaining the component (a-1) and the component (a-2) mainly comprises a titanium-containing solid catalyst component and an organoaluminum compound, or An example is a metallocene-based transition metal compound having at least one π-electron conjugated ligand.

The metallocene compound may be used with an aluminoxane as a cocatalyst, or may be used by being supported on silica or clay mineral. Specific examples of metallocene catalysts include JP-A-8-217928, JP-A-8-238731, and JP-A-8-183814.
Examples thereof include catalysts disclosed in JP-A-8-208733 and JP-A-8-85707.

The titanium-containing solid catalyst component is a known supported catalyst component obtained by contacting a solid magnesium compound, titanium tetrahalide and an electron-donating compound, or a known catalyst component containing titanium trichloride as a main component. To be elected.

Aluminum as a cocatalyst for the solid catalyst component containing titanium
The aluminum compound has the general formula AlR_nX _3-n(Where R is
Represents a hydrocarbon group having 2 to 10 carbon atoms, and n is 3 ≧ n>
It represents a number of 1.5). Titanium-containing solid catalyst composition
A carrier-supported catalyst containing a solid magnesium compound.
If it is a medium component, AlR_ThreeOr AlR_ThreeAnd AlR
_TwoIt is preferred to use a mixture of X, while the trichlorotrichloride is used.
Catalyst component containing tan or titanium trichloride as the main component
If, then AlR_TwoIt is preferred to use X. It
Furthermore, in the present invention, in addition to the above catalyst and cocatalyst component,
Use of a known electron donating compound as the third component
You can

The component (a-1) and the component (a
The polymerization reaction for obtaining -2) can be carried out, for example, in the presence or absence of an inert solvent such as hexane and heptane, in the presence of liquid propylene, or in gas phase propylene.

The method for producing the polypropylene resin composition (A), which is a composition of the component (a-1) and the component (a-2), is not particularly limited, but as a typical example, the component (a) is used.
-1) and the component (a-2) are respectively produced, and then mixed by using a mixing device, the component (a-1) is polymerized in the presence of a catalyst, and then the component (a-1) is continuously added. And a method for producing the component (a-2) by a multistage polymerization method in the presence of a catalyst, the component (a-2) is polymerized in the presence of a catalyst, and then the component (a-2) and the catalyst are continuously added. In the presence of component (a
Examples of the method include a multistage polymerization method of polymerizing -1).

From the viewpoint of dispersibility of the obtained polypropylene resin composition, the component (a-1) is polymerized in the presence of a catalyst, and then the component (a-1) and the component are added in the presence of the catalyst. A method for producing a compound (a-2) by a multistage polymerization method, in which the component (a-2) is polymerized in the presence of a catalyst, and then the component (a-2) and the component (a-2) in the presence of a catalyst. -1) is preferably produced by a multistage polymerization method of polymerizing,
From the viewpoint of polymerization efficiency, by a multistage polymerization method in which the component (a-1) is polymerized in the presence of a catalyst, and subsequently the component (a-1) and the component (a-2) are polymerized in the presence of a catalyst. The method of manufacture is particularly preferred.

In the case of the multi-stage polymerization reaction, the polymerization can be carried out batchwise by using one polymerization tank or continuously by connecting two or more polymerization tanks in series. Therefore, the polymerization is carried out in at least two stages, and additionally, the polymerization may be conducted in three stages or four stages.

The polymerization catalyst is preferably added in the first stage before the polymerization. Although replenishment of the catalyst in the latter stage is not necessarily excluded, it is preferable to add the catalyst in the first stage in order to obtain characteristics not obtained by blending the resins.

Step (1) for obtaining the component (a-1)
Polymerizes propylene or propylene and a small amount of other α-olefin in the presence of hydrogen. Hydrogen has an MFR of 10 to 1000 g / in the polymer obtained in the step (1).
It is controlled to be in the range of 10 minutes. The hydrogen concentration (in the slurry polymerization, the vapor phase concentration, the polymerization in liquid propylene or the content in the monomer in the vapor phase method) is preferably 1 to 50 mol%, more preferably 3 to 30 mol%. .

The other α-olefin copolymerized with propylene can be added intermittently or continuously supplied with propylene. In the step (1), the polymerization temperature is preferably 40 to 90 ° C., and 50 to 90% by weight, preferably 60 to 80% by weight of the total polymerization amount is produced.

Step (2) for obtaining the component (a-2)
Is a polymerization for obtaining a high molecular weight component, and it is preferable to proceed the polymerization in a substantially hydrogen-free state with a hydrogen concentration of 0.1 mol% or less. The weight average molecular weight of the polymer obtained in the step (2) is 500,000 to 10,000,000, and preferably 800,000 to 5,000,000.

The polymerization temperature is preferably 40 to 90 ° C., more preferably 50 to 80 ° C., and the α-olefin content of the comonomer is 1 to 15% by weight, preferably 3 to 10% by weight. . If the comonomer content is too high or too low, the dispersion of the high molecular weight component becomes poor and the melt tension improving effect is reduced.

The amount of the polymer obtained in the step (2) is 10 to 50% by weight, preferably 20 to 40% by weight based on the whole polymer.

Here, the weight average molecular weight is obtained by measuring both the polymer obtained after the completion of the first-stage polymerization and the final polymer using GPC, and the difference between the two and the amount of the polymer in the first-stage polymerization and the amount of the final polymer. It can be calculated from the relationship.

The polypropylene resin composition (A)
If necessary, antioxidants, colorants, ultraviolet absorbers, antistatic agents, plasticizers, slip agents such as fatty acid metal salts and fatty acid amides, polyethylene, fillers and the like may be added.

3. Foaming Method To foam the polypropylene resin composition (A),
It is preferable to use a method in which a foaming agent is added to the resin composition in an extruder and melt kneading is performed. As the foaming agent, for example,
Inorganic foaming agents, volatile foaming agents, and decomposition-type foaming agents are used, and these can be mixed and used.

Examples of the inorganic foaming agent include carbon dioxide, air, nitrogen and the like. Examples of the volatile foaming agent include propane, butane, pentane, hexane,
Cyclobutane, cyclopentane and other aliphatic hydrocarbons and cycloaliphatic hydrocarbons are monochlorodifluoromethane, trichlorofluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethane, methyl chloride,
Examples thereof include halogenated hydrocarbons such as ethyl chloride and methylene chloride. Examples of the decomposition-type foaming agent include azodicarbonamide, dinitrosopentamethylenetetramine, azobisisobutyronitrile, P, P'-
Examples thereof include oxybisbenzenesulfonyl hydrazide and sodium bicarbonate. The amount of the foaming agent added to the polypropylene resin composition, the type of foaming agent and equipment, operating conditions,
Depending on the product expansion ratio, etc., the expansion layer ratio is 2 to 8
In order to obtain a foam sheet having twice the foam layer density of 0.11 to 0.46 g / cm ³ , the polypropylene resin composition 1 is used.
It is preferable to add 1 to 10 parts by weight to 00 parts by weight.

II. Non-foamed layer 1. Non-foamed layer resin material The material of the non-foamed layer of the foamed laminated sheet of the present invention is not particularly limited as long as it is a thermoplastic resin, whether it is a non-polyolefin resin material or a polyolefin resin. The resin is preferably a non-foaming layer resin material (B) obtained by mixing 10 to 400 parts by weight of a filler with 100 parts by weight of a polyolefin resin. The polyolefin resin is not limited at all, but a propylene resin is preferable, for example,
A propylene homopolymer, a propylene / α-olefin block copolymer, and a propylene / α-olefin random copolymer are preferable. Examples of the α-olefin used in the propylene / α-olefin block copolymer and the propylene / α-olefin random copolymer include α-olefins having 2 to 20 carbon atoms excluding propylene,
For example, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1,4-methyl-hexene-1,4,4-dimethylpentene-1, etc. It can be illustrated. The propylene resin may be a single component or a mixture of two or more components.

A preferred polypropylene resin that can be used in the non-foamed layer is propylene homopolymer,
It is a propylene / α-olefin copolymer resin composition. Particularly preferably, the MFR is 10 to 1000 g / 10.
Of propylene homopolymer or propylene / α-olefin copolymer (a-1) having an α-olefin content of less than 1% by weight of 50 to 90% by weight and a weight average molecular weight of 5
The propylene random copolymer resin (a-2) having an amount of 0,000 to 10,000,000 and an α-olefin content of 1 to 15% by weight was used as 10
The polypropylene-based resin composition (A) is used in the foam layer.

Examples of the filler to be blended with the polyolefin resin in the non-foamed layer include inorganic powder type, organic powder type and fiber type fillers. Examples of the inorganic powder type filler include natural types such as silica, talc, mica and clay, and carbonates such as calcium carbonate and magnesium carbonate; hydroxides such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide; Silicates such as sodium silicate and calcium silicate; titanium oxide, iron oxide, zinc oxide,
Oxides of magnesium oxide, alumina, zeolite, etc .;
Salts such as aluminum phosphate and barium sulfate; carbon black, graphite and the like. Examples of the organic powder filler include phenol resin powder and ebonite powder. Examples of the fibrous filler include fibers such as various types of glass, pulp, asbestos, polyethylene terephthalate, polytetrafluoroethylene, and polyamide. The fillers may be used alone or in combination of two or more.

The amount of the filler compounded is preferably 10 to 400 parts by weight, more preferably 10 to 100 parts by weight, based on 100 parts by weight of the polyolefin resin. If the blending amount is less than 10 parts by weight, there is little improvement in rigidity, heat resistance and corrugation prevention performance of the foamed laminated sheet as a whole,
On the contrary, if it exceeds 400 parts by weight, extrusion molding may become difficult.

If necessary, antioxidants, colorants, ultraviolet absorbers, antistatic agents, plasticizers, and slip agents such as fatty acid metal salts and fatty acid amides may be added to the polyolefin resin. .

III. Foamed Laminated Sheet The layered structure of the foamed laminated sheet of the present invention is not particularly limited as long as it is composed of two or more layers including the foamed layer and the non-foamed layer in contact with the foamed layer, but preferably the foamed layer A three-layer structure in which a non-foamed layer is laminated on both sides is mentioned. or,
Further, if necessary, a skin layer made of a resin material selected from the same polyolefin-based resins as the material of the non-foaming layer may be laminated on one or both outer sides of the non-foaming layer, which is required. It can be selected according to the quality (for example, gloss, surface decoration, antifouling, heat sealability, etc.).

In the method for producing a foamed laminated sheet of the present invention, a mixture of the polypropylene resin composition (A) and a foaming agent and a non-foaming layer resin material (B) containing no foaming agent are used.
It is a method including a step of forming a foamed layer and a non-foamed layer in contact with it by melt extrusion from a die. According to this manufacturing method, the foamed laminated sheet of the present invention can be obtained easily at a lower cost and in a smaller space.

That is, the method of laminating the non-foamed layer on the surface in contact with the foamed layer may be any method as long as it is a method of laminating the resin material forming each of the above layers in a molten state before being extruded from the die. For example, a multi-manifold system in which both materials are melt-kneaded by an extruder and then stacked in a die, a feed block system (combining adapter system) in which the materials are stacked before flowing into the die, and the like may be used. As the shape of the die, either a T-type die or an annular die can be used.

A preferred method for producing a foamed laminated sheet of the present invention comprises a mixture of the polypropylene resin composition (A) of the present invention and a foaming agent, and a non-foaming layer resin material (B) containing no foaming agent. This is a method of forming a foamed layer and a non-foamed layer in contact with it by melt-extruding in a sheet form from a die.

Another preferred method for producing the foamed laminated sheet of the present invention comprises a mixture of a polypropylene resin composition (A) and a foaming agent, and a non-foaming layer resin material (B) containing no foaming agent. It is supplied to the extruder, and both raw materials are merged and laminated inside the annular die so that the non-foamed layer is integrated on both sides of the foamed layer, and then coextruded into a tubular shape from the annular die to foam the raw material for the foamed layer. After obtaining a tubular foamed laminate having a non-foamed layer on the inner and outer surfaces of the foamed layer, the tubular inner surface of the laminated body is then drawn while contacting with a cylindrical cooling drum, cooled, and then cut open to foam. It is a method of forming a laminated sheet.

The density and thickness of the foam layer are determined by the amount of foaming agent added,
It can be adjusted by the extrusion temperature, the extrusion amount per unit time, the take-up speed of the laminated sheet, and the like.

Furthermore, when laminating the above-mentioned skin layer as required, a commonly used laminating method such as a dry laminating method, a wet laminating method, an extrusion laminating method, a co-extrusion method and a pressing method may be used.

When a non-polyolefin resin material is used for the non-foaming layer, an adhesive layer is laminated between the non-foaming resin layer and the non-foaming layer for the purpose of enhancing the adhesion between the foaming layer and the non-foaming layer. A mixture of a resin material for foam molding of the composition (A) and a foaming agent, a non-polyolefin resin material,
And, the adhesive resin is produced by melt-extruding the adhesive resin into a sheet shape from a die so that the adhesive resin is laminated between the mixture and the non-polyolefin resin material.

When a laminate of a resin layer made of a non-polyolefin resin material and a resin layer made of a polyolefin resin material is used as the non-foamed layer, the same applies when an adhesive layer is provided between both resin layers. It is manufactured by melt-extruding the adhesive resin into a sheet shape from a die so as to be laminated between both resin layers.

[0060]

EXAMPLES The present invention will be described with reference to examples, but the present invention is not limited to these examples. The test methods used in the examples and the production examples of the polypropylene resin composition are as follows.

1. Test method (1) Foaming ratio: A foamed laminated sheet was cut into 10 cm squares, the overall density of the laminated foamed sheet was calculated from the weight and thickness, and the foamed layer density in the foamed laminated sheet was calculated from the non-foamed layer density calculated in advance. Then, it was calculated by the following formula. Foaming ratio = (density when not foamed) ÷ (density when foamed) (2) Cellular property: The cross section of the foamed sheet was observed with an optical microscope, and the diameter of the cells in the foamed layer was measured and evaluated according to the following criteria. ⊚ = uniform fine (cell diameter 100 μm or less) ○ = uniform (cell diameter 100 to 200 μ) × = non-uniform, coarse (cell diameter 30 μm or more) (3) closed cell ratio: measured according to ASTM-D2856, It was judged according to the standard. ◎ = 85% or more ○ = 70 to 85% △ = 50 to 70% × = less than 50% (4) Drawdown property: The foam laminated sheet is fixed to a jig of 30 cm square and set in a heat insulation box, and then a sample It is heated under the condition of a preset temperature of 450 ° C by the heaters installed above and below. Here, the drawdown property was evaluated based on the amount of sag when the sheet was heated for 35 seconds from the start of heating, based on the following criteria. ⊚ = less than 15 mm ○ = 15 to less than 20 mm Δ = 20 m or more (5) Presence or absence of corrugation (surface smoothness): The number of corrugated sheets generated at the die exit was visually observed and evaluated according to the following criteria. ⊚: Does not occur in full width ○: Almost does not occur (several lines at both ends) Δ: Slightly occurs (5 to 10 lines in total width) ×: Occurs in the entire width direction (20 lines or more)

2. Production of Resin Composition Production Example 1 70 liters of n-heptane and a magnesium-supporting titanium catalyst were placed in a stainless steel autoclave having an internal volume of 200 liters (solid catalyst prepared in the same manner as in Example 1 of JP-A-4-348113). 3 g and 10 g of triethylaluminum were added, the temperature was raised to 70 ° C., and hydrogen and propylene were supplied to produce 70% by weight of all polymers of a propylene homopolymer having an MFR of 50 g / 10 min (step 1). Next, hydrogen was purged to supply ethylene and propylene, and an ethylene / propylene copolymer having an ethylene content of 10% by weight and a weight average molecular weight of 4.8 million was produced at 30% by weight of the entire polymer (step 2) to obtain a resin composition. -1 was obtained. Table 1 shows the physical properties of the obtained resin composition.

Production Examples 2 to 7 Polymerization was carried out in the same manner as in Production Example 1 except that the polymerization conditions in Step 1 and Step 2 were changed as shown in Table 1. Resin Composition-2 to Resin Composition-7. Got Table 1 shows the physical properties of the obtained resin composition.

[0064]

[Table 1]

Example 1 As a foaming layer, a carbon dioxide generating chemical blowing agent (EE4 manufactured by Eiwa Kasei Co., Ltd.) was added to 100 parts by weight of the resin composition-1 shown in Table 1.
05) Using a mixture of 2.7 parts by weight, as a non-foamed layer, a propylene-ethylene block copolymer (PP;
MFR = 0.5 g / 10 minutes, "Nippon Polychem Novatec EC9") 100 parts by weight and 50 parts by weight of talc as a filler were melt-kneaded in an extruder, respectively, and then kneaded. Was laminated in three layers immediately before the T die by a feed block method, and this was extruded from the T die to obtain a multilayer foam sheet. The evaluation results of the sheet are shown in Table 2. The extruder used has a diameter of 65 mmφ in the case of a foamed layer resin, and has a diameter of 90 mmφ in the case of a non-foamed layer resin, and the width of the T die is 7 mm.
A 50 mm one was used.

Example 2 A multilayer foam sheet was obtained in the same manner as in Example 1 except that the resin composition used in the foam layer was changed to Resin composition-2. The evaluation results of the sheet are shown in Table 2.

Example 3 A multilayer foam sheet was obtained in the same manner as in Example 1, except that the resin composition used in the foam layer was changed to Resin composition-3. The evaluation results of the sheet are shown in Table 2.

Example 4 A multilayer foam sheet was obtained in the same manner as in Example 1 except that the resin composition used in the foam layer was replaced with Resin composition-4. The evaluation results of the sheet are shown in Table 2.

Example 5 A multilayer foam sheet was obtained in the same manner as in Example 1 except that the resin composition used in the foam layer was changed to Resin composition-5. The evaluation results of the sheet are shown in Table 2.

Example 6 A multilayer foamed sheet was obtained in the same manner as in Example 1 except that the propylene resin used in the non-foamed layer was replaced with the resin composition-1.
The evaluation results of the sheet are shown in Table 2.

Comparative Example 1 A foamed sheet was obtained in the same manner as in Example 1 except that a non-foamed layer was not provided and a single layer sheet having a thickness of 0.8 mm was used. The evaluation results of the sheet are shown in Table 2.

Comparative Example 2 A multilayer foam sheet was obtained in the same manner as in Example 1 except that the resin composition used in the foam layer was replaced with Resin composition-6. The evaluation results of the sheet are shown in Table 2.

Comparative Example 3 A multilayer foam sheet was obtained in the same manner as in Example 1 except that the resin composition used in the foam layer was replaced with Resin composition-7. The evaluation results of the sheet are shown in Table 2.

[0074]

[Table 2]

As is clear from Table 2, in Examples 1 to 5, corrugations were hardly generated only at the end portions, the surface was smooth, and the bubbles were uniform and fine. In Example 6, corrugations did not occur over the entire width, the surface was smooth, and the bubbles were uniformly fine. The drawdown during thermoforming was also extremely small and good. On the other hand, in Comparative Example 1 in which the non-foamed layer was not used, the cell properties were good, but corrugations were generated on the entire surface. MT and MFR
In Comparative Example 2 in which a resin composition having a relationship outside the above range was used for the foam layer, the drawdown property was good, but corrugations were slightly generated, and the bubble properties were nonuniform and coarse. M
In Comparative Example 3 in which a resin composition having a relationship between T and MFR and τd outside the range was used in the foam layer, some corrugation occurred, the bubble properties were nonuniform and coarse, and the drawdown property was poor.

[0076]

The foamed laminated sheet of the present invention has a foaming ratio of
Since it is a foamed laminated sheet that has excellent foaming characteristics such as closed cell ratio and bubble properties, drawdown properties, corrugation does not occur, and has excellent secondary processability, it can be used as a sheet with excellent impact resistance, heat insulation, etc. It can be used as a material useful as an industrial material in the field.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08J 9/04 101 C08J 9/04 101 CES CES C08L 23/14 C08L 23/14 // B29K 23:00 B29K 23:00 105: 04 105: 04 B29L 7:00 B29L 7:00 (72) Inventor Takumi Matsuno 1 Toho-cho, Yokkaichi-shi, Mie F-Term (Reference) at Material Development Center of Japan Polychem Co., Ltd. 4F074 AA24 AA24A AB01 AB02 AB05 BA03 BA13 BA14 BA16 BA18 BA32 BA33 BA35 BA36 BA37 BA38 BA39 BA40 BA44 BA45 BA53 BA54 BA55 BA57 BA59 CA22 4F100 AC10 AK03A AK03C AK07A AK07C AK64 AK66A AK66B JA66 JA06 CA06BJA CA06B06 CA06B06 BA01 BA02 BA03 BA06 BA01 BA23 BA06 BA23 BA06 BA06 BA01 BA23 BA06 BA01 BA23 JA15 JA15A JJ02 JK02B JK15 JK20B JL01 JL03 4F207 AA11 AA11E AB02 AG01 AG03 AG08 KA01 KA11 KA17 KW21 4J002 BB121 BB122 BB141 BB142 DE016 DE206 EA016 EA026 EB026 EB066 EQ016 ES006 EV266FD326

Claims (6)

[Claims] 1. A characteristic (A-1) to a characteristic (A-3) comprising at least the following component (a-1) and component (a-2):
A polyolefin resin foamed laminated sheet comprising a foamed layer made of the polypropylene resin composition (A) having the above physical properties and a non-foamed layer in contact with the foamed layer. Component (a-1): Propylene homopolymer having MFR of 10 to 1000 g / 10 min or propylene / α-olefin copolymer having an α-olefin content other than propylene of less than 1% by weight 50 to 90% by weight Component (a) -2): Weight average molecular weight of 500,000 to 1,000
The content of α-olefin other than propylene is 1 to 15
Wt% propylene / α-olefin copolymer 10-
50 wt% Characteristic (A-1): MFR is 0.1 to 20 g / 10 minutes Characteristic (A-2): Melt tension (MT) and MFR satisfy the following relationship. logMT> −0.97 × logMFR + 1.23 Characteristic (A-3): Maximum relaxation time (τd) is 100 seconds or more. 2. The non-foaming layer is composed of a non-foaming layer resin material (B) obtained by mixing 10 to 400 parts by weight of a filler with 100 parts by weight of a polyolefin resin. Item 3. A polyolefin resin foamed laminated sheet according to item 1. 3. The polyolefin resin foam laminated sheet according to claim 2, wherein the polyolefin resin forming the non-foamed layer is the polypropylene resin composition (A). 4. A method for producing a foamed laminated sheet having a foamed layer and a non-foamed layer in contact with the foamed layer, which comprises a mixture of the polypropylene resin composition (A) and a foaming agent, and the non-foamed layer. Production of a polyolefin resin foam laminated sheet, comprising a step of melt-coextruding the layer resin material (B) into a sheet shape from a die to form the foam layer and a non-foam layer in contact with the foam layer. Method. 5. A method for producing a foamed laminated sheet having a foamed layer and a non-foamed layer in contact with the foamed layer, the mixture comprising the polypropylene resin composition (A) and a foaming agent, and the non-foamed layer. After joining the layer resin material (B) inside the die, the layer resin material (B) is extruded through an annular die to form a tubular laminate in which non-foam layers are laminated on both sides of the foam layer, and then the inner surface side of the tubular laminate is A method for producing a polyolefin-based resin laminated foam sheet, which comprises contacting with a peripheral surface of a cylindrical cooling drum, cooling while taking it off, and cutting the sheet into a sheet shape. 6. The polyolefin resin foam according to claim 4, wherein the polyolefin resin constituting the non-foaming layer resin material (B) is the polypropylene resin composition (A). Laminated sheet manufacturing method.