JP2017036388A - Polyurethane foam and manufacturing method therefor - Google Patents

Abstract

Disclosed is a method for producing a polyurethane foam excellent in flame retardancy without reducing the reactivity during the production of the polyurethane foam.
A polyurethane foam obtained from at least a polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant, and a polymerization inhibitor, wherein (a) a part of the polyol is an ester of an alcohol component and a carboxylic acid component The polyester polyol (A) obtained by the conversion reaction, and (b) fumaric acid and / or maleic acid as a carboxylic acid component used in the polyester polyol (A) with respect to all carboxylic acid components in the polyester polyol (A) 10 mol% or more and, as an alcohol component, a diol having an alkyl group in the side chain is used in an amount of 10 mol% or more based on the total alcohol component in the polyester polyol (A), and (c) the polyester polyol (A) Polyureta containing 1 to 10,000 ppm by mass of the polymerization inhibitor Manufacturing method of the form.
[Selection figure] None

Description

  The present invention relates to a polyurethane foam having excellent flame retardancy and a method for producing the same.

  In general, polyurethane foams are prepared as a mixed liquid (premix liquid) and a polyisocyanate liquid in which polyols such as polyether polyol and / or polyester polyol, foaming agent, catalyst, surfactant, and flame retardant as necessary are mixed. And they are manufactured by a method of mixing and foaming and curing in a short time. Since polyurethane foam has excellent heat insulating properties, it is widely used in the form of spraying, pouring, board or panel, etc. in refrigerators, refrigerators, freezing rooms, freezers, heat insulating materials for general buildings, and the like.

  In addition to heat insulation, flame retardance is listed as a physical property required for polyurethane foams, and even higher flame retardancy is required when used as a heat insulating wall construction member for general buildings. In recent years, in particular, due to the revision of the Building Standards Law, international standards have been introduced for the fireproof material test (flame retardant, semi-flame retardant, non-flammable material) using the corn calorimeter test, and the demand for higher flame resistance of polyurethane foam is required. Is getting higher.

  As a method for improving the flame retardancy of polyurethane foam, isocyanurate modification in which isocyanate is trimerized using a potassium-based or quaternary ammonium salt-based catalyst is generally performed. However, although isocyanurate modification is effective in improving flame retardancy, when it is introduced in a large amount, the so-called liquid ratio of the premix liquid and the polyisocyanate liquid is out of the practical range, or the resulting polyurethane foam is brittle. And the problem that adhesiveness deteriorates arises. That is, the actual situation is that the flame retardancy is insufficient from a practical viewpoint.

  Furthermore, it is essential to use an aromatic polyester polyol as the polyol, and it has been proposed to use a polyester polyol having an aromatic ring concentration of 24% by weight or more (Patent Document 1). However, when the aromatic ring concentration is increased, the polyester polyol is easily crystallized, and there are problems in viscosity, solubility in a foaming agent, and the like.

  In addition to the above, in order to improve the flame retardancy of polyurethane foam, chlorendic acid type polyol which is one kind of chlorinated carboxylic acid may be used, and esterification reaction of chlorendic acid and polyhydric alcohol such as diethylene glycol is carried out. A polyester polyol obtained in this way has been proposed (Patent Document 2). However, such halogen-based polyols are never preferable in view of environmental load, and are not satisfactory in improving flame retardancy.

  As another method, a method using a large amount of a phosphate ester flame retardant such as trismonochloropropyl phosphate has been proposed (Patent Document 3). However, when a large amount of a phosphate ester flame retardant is used, it itself has no reaction point and acts as a plasticizer, which causes a problem of causing a decrease in strength of the resulting polyurethane foam.

  Thus, in order to meet the demand for high flame retardancy of polyurethane foam, so-called those skilled in the art have been studied, it is very difficult to achieve both the flame retardancy and the necessary physical properties as a heat insulating material, In reality, the above aromatic polyester polyols have problems such as crystallinity and viscosity but must be used in a large amount.

JP 2008-88356 A JP-A-6-172480 JP 2009-149760 A

  This invention is made | formed in view of the said situation, The objective is to provide the manufacturing method of the polyurethane foam excellent in the flame retardance, without reducing the reactivity at the time of polyurethane foam manufacture.

  As a result of intensive studies by the present inventors, the inventors have obtained knowledge that the above-mentioned problems can be solved by using a polyester polyol having a specific structural characteristic as a polyol for producing a polyurethane foam. It came to.

(1) A polyurethane foam obtained using at least polyisocyanate, polyol, foaming agent, catalyst, surfactant and polymerization inhibitor as raw materials,
(A) A part of the polyol is a polyester polyol (A) obtained by an esterification reaction of an alcohol component and a carboxylic acid component,
(B) As the carboxylic acid component used in the polyester polyol (A), fumaric acid and / or maleic acid is 10 mol% or more based on the total carboxylic acid component in the polyester polyol (A), and the side chain as the alcohol component. The diol having an alkyl group is used in an amount of 10 mol% or more based on the total alcohol components in the polyester polyol (A),
(C) containing 1 to 10,000 ppm by mass of the polymerization inhibitor relative to the polyester polyol (A),
Polyurethane foam characterized by that.

(2) As a part of the polyol, 10 to 90 parts by weight of an aromatic polyester polyol (B) (excluding the polyester polyol (A)) is used with respect to 100 parts by weight of the polyol. The polyurethane foam as described in (1).

(3) A polyurethane foam production method using at least a polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and a polymerization inhibitor as an atomic weight,
(A) A part of the polyol is a polyester polyol (A) obtained by an esterification reaction of an alcohol component and a carboxylic acid component,
(B) As the carboxylic acid component used in the polyester polyol (A), fumaric acid and / or maleic acid is 10 mol% or more based on the total carboxylic acid component in the polyester polyol (A), and the side chain as the alcohol component. The diol having an alkyl group is used in an amount of 10 mol% or more based on the total alcohol components in the polyester polyol (A),
(C) containing 1 to 10,000 ppm by mass of the polymerization inhibitor relative to the polyester polyol (A),
A process for producing a polyurethane foam, characterized in that

(4) As a part of the polyol, 10 to 90 parts by weight of an aromatic polyester polyol (B) (excluding the polyester polyol (A)) is used with respect to 100 parts by weight of the polyol. The method for producing a polyurethane foam according to (3).

(5) The method for producing a polyurethane foam according to (3) or (4), wherein a foaming agent having an ozone depletion coefficient of 0.1 or less is used.

(6) The polyurethane foam according to (3) or (4), wherein at least one selected from a hydrofluoroolefin-based blowing agent, a hydrocarbon-based blowing agent or water is used as the blowing agent.

(7) The method for producing a polyurethane foam according to any one of (3) to (6), wherein polymeric MDI is used as the polyisocyanate.

  According to the method for producing a polyurethane foam of the present invention, it is possible to provide a method for producing a polyurethane foam excellent in flame retardancy without reducing the reactivity during the production of the polyurethane foam.

  Hereinafter, the present invention will be described in detail.

(Polyurethane foam)
The present invention is a polyurethane foam obtained using at least polyisocyanate, polyol, foaming agent, catalyst, surfactant and polymerization inhibitor as raw materials,
(A) A part of the polyol is a polyester polyol (A) obtained by an esterification reaction of an alcohol component and a carboxylic acid component,
(B) As the carboxylic acid component used in the polyester polyol (A), fumaric acid and / or maleic acid is 10 mol% or more based on the total carboxylic acid component in the polyester polyol (A), and the side chain as the alcohol component. The diol having an alkyl group is used in an amount of 10 mol% or more based on the total alcohol components in the polyester polyol (A),
(C) containing 1 to 10,000 ppm by mass of the polymerization inhibitor relative to the polyester polyol (A),
This is a polyurethane foam characterized in that.

  Hereinafter, each component which comprises this polyurethane foam is demonstrated.

(Polyol)
First, the polyol used in the polyurethane foam of the present invention refers to a known one used in the production of at least one polyurethane foam selected from polyester polyol, polyether polyol, polymer polyol and the like.

  The polyester polyol is obtained by an esterification reaction between a carboxylic acid component and an alcohol component. In the present invention, a polyester polyol (A) comprising fumaric acid and / or maleic acid is used as an essential component as the carboxylic acid component. Fumaric acid and / or maleic acid is usually used in an amount of 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more based on the total carboxylic acid component in the polyester polyol (A). When fumaric acid and / or maleic acid is less than 10 mol%, the effect of improving flame retardancy is reduced. On the other hand, the upper limit of fumaric acid and / or maleic acid is not particularly limited, and all of the carboxylic acid component may be fumaric acid and / or maleic acid.

  As other carboxylic acid components that can be used in combination with fumaric acid and / or maleic acid, known carboxylic acids generally used for the production of polyester polyols can be used. Specifically, phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, het acid, dimer acid, malic acid, citric acid, acetic acid Or a benzoic acid etc. are mentioned. These may be used as derivatives such as acid anhydrides and methyl esters, respectively, or two or more of them may be used in combination.

  If these carboxylic acids are used in combination, it is preferable to use at least one selected from phthalic acid, terephthalic acid, and isophthalic acid from the viewpoint of improving the flame retardancy of the polyurethane foam. The total amount of phthalic acid, terephthalic acid, and isophthalic acid used is usually 1 to 90 mol%, preferably 5 to 80 mol%, more preferably 10 to 70, based on all carboxylic acid components in the polyester polyol (A). Mol%. Moreover, it is preferable to use a succinic acid and / or adipic acid from a viewpoint of improving the adhesiveness and surface property of a polyurethane foam. The usage-amount of a succinic acid and adipic acid is 1-90 mol% normally with respect to all the carboxylic acid components in a polyol, Preferably it is 5-80 mol%, More preferably, it is 10-70 mol%.

  As the alcohol component of the polyester polyol (A), a diol having an alkyl group in the side chain is used. Such diols include 1,2-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 3-methyl-1,5-pentanediol, Examples include 2,4-diethyl-1,5-pentanediol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and polyoxyethylene / oxypropylene copolymer glycol. Two or more of these may be used in combination.

  The diol having an alkyl group in the side chain is usually used in an amount of at least 10 mol%, preferably at least 20 mol%, more preferably at least 30 mol%, based on all alcohol components in the polyester polyol (A). When the diol having an alkyl group in the side chain is less than 10 mol%, the effect of improving the hydrolysis resistance is reduced. On the other hand, the upper limit of the diol having an alkyl group in the side chain is not particularly limited, and all of the alcohol components may be diol having an alkyl group in the side chain.

  As other alcohol components that can be used in combination with a diol having an alkyl group in the side chain, known alcohols generally used for the production of polyester polyols can be used. Specific examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polytetramethylene ether glycol, and the like. Examples include chain polyether polyol, glycerin, trimethylolpropane, pentaerythritol and the like. Two or more of these may be used in combination.

  If these alcohols are used in combination, diethylene glycol is preferably used. The usage-amount of diethylene glycol is 1-90 mol% normally with respect to the alcohol component of polyester polyol (A), Preferably it is 5-80 mol%, More preferably, it is 10-70 mol%. When diethylene glycol is 90 mol% or more, the effect which improves hydrolysis resistance becomes small.

  The hydroxyl value of the polyester polyol (A) is usually in the range of 30 to 500 mgKOH / g, preferably 40 to 480 mgKOH / g, more preferably 50 to 450 mgKOH / g. When the hydroxyl value is smaller than 30 mgKOH / g, the mechanical strength of the resulting polyurethane foam may be lowered. On the other hand, when it is larger than 500 mgKOH / g, it has a molecular weight distribution with a large amount of unreacted alcohol, which may deteriorate brittleness and adhesiveness.

  The viscosity at 25 ° C. of the polyester polyol (A) is usually 50000 mPa · s or less, preferably 45000 mPa · s or less, more preferably 40000 mPa · s or less. When it is higher than 50000 mPa · s, there is a possibility that the handling may be hindered. On the other hand, there is no lower limit of viscosity.

  Moreover, monovalent alcohols, such as methanol, ethanol, isopropanol, 2-ethylhexanol, can also be used together as a method of reducing the viscosity of the polyester polyol (A). However, when these monohydric alcohols are used, it is important that the hydroxyl value and the number of functional groups are not deviated from the above ranges. Furthermore, in the production of the polyester polyol, the monohydric alcohol may be distilled out of the reaction system to deteriorate the yield, or the strength and flame retardancy of the polyurethane foam using the obtained polyester polyol may be adversely affected. Therefore, it is preferable to use it within a range that does not cause a practical problem.

  The average functional group number of the polyester polyol (A) is usually 1.0 to 4.0, preferably 1.2 to 3.8, and more preferably 1.5 to 3.5. If the average number of functional groups is less than 1.0, there may be adverse effects such as a decrease in mechanical strength and dimensional stability of the polyurethane foam. On the other hand, when it is larger than 4.0, the viscosity of the polyester polyol is increased, which may cause a problem.

  In the production of the polyester polyol (A), an esterification catalyst is usually used as a catalyst. In general, an acid catalyst is often used as the esterification catalyst. Specifically, orthotitanate such as tetraisopropyl titanate and tetra-n-butyl titanate, tin compounds such as diethyltin oxide and dibutyltin oxide, and metal compounds such as zinc oxide are used. Also, a Bronsted acid such as paratoluenesulfonic acid may be used.

  The amount of the esterification catalyst used is usually 0.1% by weight or less, preferably 0.07% by weight or less, more preferably 0.05% by weight or less, based on the total charged weight of the alcohol component and the carboxylic acid component. Depending on the use of the polyurethane foam, the reaction may be performed without using an esterification catalyst, or a deactivation treatment may be performed after the reaction, or it may be removed by purification or the like.

  In the production of the polyester polyol (A), the end point of the esterification reaction is usually determined by the amount of unreacted carboxyl groups of the carboxylic acid used. On the other hand, the presence of acid content in the premix liquid for polyurethane foam production may reduce the reactivity of urethanization due to the action of amine-based catalysts and the like, and may affect the storage stability of the premix liquid. . Therefore, the amount of unreacted carboxylic acid, that is, the acid value is preferably as low as possible. The acid value of the polyester polyol (A) of the present invention is usually 10 mgKOH / g or less, preferably 5 mgKOH / g or less, more preferably 3 mgKOH / g or less. On the other hand, there is no particular lower limit for the acid value.

  In the production of the polyester polyol (A), the reaction conditions such as the reaction temperature of the esterification reaction and the reaction pressure are not particularly limited, and known methods can be used.

(Polymerization inhibitor)
In producing a polyurethane foam using the polyester polyol (A), a polymerization inhibitor is added in advance. This is to prevent the storage stability from deteriorating due to polymerization of the polyester polyol (A). A known polymerization inhibitor can be used as the polymerization inhibitor. Specifically, hydroquinone such as hydroquinone, methylhydroquinone, 2-methylhydroquinone and t-butylhydroquinone, benzoquinone such as p-benzoquinone and methyl-p-benzoquinone, 1,4-naphthoquinone, 2-methyl-1, Naphthoquinones such as 4-naphthoquinone and 2-hydroxy-1,4-naphthoquinone, naphthoquinones such as 1,4-naphthohydroquinone and 2-methyl-1,4-naphthoquinone, catechol such as catechol and t-butylcatechol , Phenols such as 2,6-di-t-butyl-4-methylphenol, 4-methoxyphenol, cresol, N such as 1-oxyl-2,2,6,6-tetramethylpiperidin-4-ol -Oxyl-based, others, phenothiazine, ferdazil, α Known polymerization inhibitors such as α- diphenyl -β- picrylhydrazyl and the like. Two or more kinds of these polymerization inhibitors may be used.

  The usage-amount of a polymerization inhibitor is 1-10000 mass ppm normally with respect to polyester polyol (A), Preferably it is 5-8000 mass ppm, More preferably, it is 10-5000 mass ppm. When the amount used is less than 1 ppm by mass, the effect of preventing polymerization is small and the storage stability deteriorates. On the other hand, although it may exceed 10,000 mass ppm, a sufficient effect is obtained at 10,000 mass ppm from the viewpoint of preventing polymerization.

  The polymerization inhibitor may be added together with the carboxylic acid or alcohol before the esterification reaction, may be added sequentially during the esterification reaction, or may be added after the esterification reaction is completed. Moreover, you may divide and add twice or more like before and after reaction. Considering that a part of the polymerization proceeds during the esterification reaction, it is most preferable to add these polymerization inhibitors before the start of the esterification reaction.

  The amount of the polyester polyol (A) used is usually 10 parts by weight or more, preferably 20 parts by weight or more, more preferably 30 parts by weight or more, in 100 parts by weight of the total polyol. When the amount used is less than 10 parts by weight, the flame retardancy of the polyurethane foam is lowered. On the other hand, there is no particular upper limit on the amount used, and the total amount of polyol may be the polyester polyol (A).

  In the production of the polyurethane foam of the present invention, as a polyol that can be used in addition to the above polyester polyol (A), a known polyester polyol having a hydroxyl value of 20 to 800 mgKOH / g and a functional group number of 1.0 to 8.0, Examples include ether polyols and polymer polyols, and commercially available ones can be used. These may be used alone or in combination of two or more.

  In particular, from the viewpoint of improving the flame retardancy of the polyurethane foam, in addition to the polyester polyol (A), an aromatic polyester polyol (B) (however, different from the polyester polyol (A)) can be used. In 100 parts by weight of all polyols, it is usually 10 to 90 parts by weight, preferably 20 to 80 parts by weight, and more preferably 30 to 70 parts by weight.

  The aromatic polyester polyol (B) refers to those produced by using aromatic carboxylic acid among carboxylic acid components in an amount of usually 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more. Examples of the aromatic carboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, benzoic acid and the like. In addition to the aromatic carboxylic acid, known carboxylic acids generally used for the production of polyester polyols can be used. Moreover, as alcohol component, the well-known alcohol generally used for manufacture of a polyester polyol can be used.

  As polyester polyols other than the above, one or more types of 1 to 4 carboxylic acids such as phthalic acid, terephthalic acid, adipic acid, and succinic acid, and 1 type of tetravalent alcohols such as ethylene glycol, diethylene glycol, and propylene glycol are used. Known polyester polyols such as those obtained by esterification reaction with the above and polyester polyols obtained by ring-opening polymerization such as butyrolactone and caprolactone can be used.

  Examples of polyether polyols include those obtained by polymerizing one or more alkylene oxides such as ethylene oxide and propylene oxide, using alcohols such as ethylene glycol and glycerin, and amines such as ethylenediamine and toluenediamine as initiators. Well-known polyether polyols such as Mannich-modified polyols can be used.

  Examples of the polymer polyol include a polymer polyol obtained by grafting an ethylenically unsaturated compound such as acrylonitrile, styrene, vinyl acetate, or (meth) acrylate to a polyester polyol or a polyether polyol.

  Moreover, compounds having two or more active hydrogens in one molecule such as alcohols such as ethylene glycol, diethylene glycol and glycerin, alkanolamines such as diethanolamine and triethanolamine can be used in combination.

(Foaming agent)
In the production of the polyurethane foam of the present invention, a foaming agent is used. Examples of the blowing agent include a blowing agent having an ozone depletion coefficient of 0.1 or less, for example, a hydrofluorocarbon blowing agent such as HFC-245fa and HFC-365mfc, a hydrocarbon blowing agent such as pentane and cyclopentane, and HFO- Examples thereof include hydrofluoroolefin-based blowing agents such as 1234ze, HFO-1234yf, HCFO-1233zd, and HFO-1336mzz, water, and carbon dioxide gas. In addition, water acts as a foaming agent by generating carbon dioxide gas by reaction with polyisocyanate.

(catalyst)
As a catalyst, the well-known catalyst used for manufacture of a normal polyurethane foam can be used. For example, in addition to amine-based catalysts such as triethylenediamine and N, N-tetramethylhexanediamine, tin-based catalysts such as dibutyltin dilaurate and tin octylate, and lead-based catalysts such as lead octylate and the like can be used. . Examples of the trimerization catalyst for isocyanate include potassium-based, quaternary ammonium salt-based, and triazine-based catalysts. Commercially available catalysts can be used for these. The blending amount of the catalyst is appropriately selected depending on the reactivity and physical properties of the target polyurethane foam, but it is general to combine a foaming catalyst, a resinification catalyst, a balanced catalyst, a trimerization catalyst and the like.

(Surfactant)
In the production of the polyurethane foam of the present invention, a surfactant is used. The surfactant may be any of nonionic, anionic and cationic, but is preferably a nonionic surfactant, and particularly preferably a silicone surfactant. The amount of these surfactants used is 0.5 to 10 parts by weight with respect to 100 parts by weight of the polyol, and two or more kinds of surfactants may be used.

(Other auxiliaries)
In the production of the polyurethane foam of the present invention, it can be used as an additive or auxiliary agent depending on the application. For example, a flame retardant and a viscosity reducer are mentioned as a typical additive. Specifically, chloroalkyl phosphates, tris (beta chloroethyl) phosphate or tris (beta chloropropyl) phosphate can be used as a flame retardant, and propylene carbonate or tetraglyme is used as a viscosity reducing agent. can do. Additives and auxiliaries other than those described above are not particularly limited, and can be used as long as they do not have a significant adverse effect as long as they are used for the purpose of improving physical properties or operability. .

(Polyisocyanate)
The polyisocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups in one molecule. Examples thereof include aliphatic, alicyclic, aromatic polyisocyanates, and modified products thereof. Specific examples include hexamethylene diisocyanate, isophorone diisocyanate, or polyisocyanate. Examples of polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, and the like, and these carbodiimide-modified products and prepolymers. Modified products such as these can also be used. The polyester polyol (A) of the present invention can also be used for the production of the prepolymer.

  Preferred polyisocyanates are aromatic polyisocyanates or modified products thereof, and particularly preferred are diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, tolylene diisocyanate, and modified products thereof. Two or more of these may be used in combination. As the polyphenylene polymethylene polyisocyanate, those having an isocyanate group content of usually 25 to 35% by weight and a viscosity of usually 500 mPa · s (25 ° C.) or less are preferably used.

  Practically, as the polyisocyanate liquid, in addition to the above polyisocyanate, additives and auxiliaries may be mixed with the polyisocyanate and used depending on the application. For example, for the purpose of improving the mixing property with the aforementioned polyurethane foam composition, a surfactant used also in the polyurethane foam composition may be used in combination as a compatibilizing agent. In this case, a nonionic surfactant is preferable, and a silicone surfactant is particularly preferable. Moreover, a flame retardant may be used together for the purpose of improving flame retardancy and adjusting viscosity. Usually, chloroalkyl phosphates such as tris (betachloroethyl) phosphate and tris (betachloropropyl) phosphate are used. Additives and auxiliaries other than those described above are not particularly limited, and are used for the purpose of improving physical properties and operability in ordinary resins. I do not care.

  In the polyurethane foam of the present invention, the isocyanate index of the polyurethane foam can be determined from the formula [(number of moles of all isocyanate groups) / (number of moles of all active hydrogen groups) × 100], usually 50 to 400, preferably Is 60 to 390, more preferably 70 to 380. When the isocyanate index is less than 50, the resulting rigid polyurethane foam may not have sufficient strength. On the other hand, when it exceeds 400, the resulting rigid polyurethane foam tends to have high brittleness and lower adhesive strength. Therefore, it is not preferable.

The density of the polyurethane foam of the present invention is expressed by the core density of the free foam, and is 10 to 60 kg / m ³ , preferably 15 to 55 kg / m ³ , more preferably 20 to 50 kg / m ³ . When the density is less than 10 kg / m ³ , the obtained polyurethane foam does not have sufficient flame retardancy and mechanical strength, and when it exceeds 60 kg / m ³ , the cost becomes high.

  The closed cell ratio of the polyurethane foam of the present invention is not particularly limited, but is preferably 70% or more in order to obtain good flame retardancy. On the other hand, depending on the use of the polyurethane foam, the closed cell ratio may be 50% or less in order to prevent shrinkage.

(Polyurethane foam manufacturing method)
The method for producing the polyurethane foam of the present invention is a method in which a polyol, a foaming agent, a catalyst, a surfactant and a polyisocyanate are mixed and foam-cured, but in practice, the polyisocyanate is liquid A and the polyol is B. As a liquid (premix liquid), water, a catalyst, a surfactant and other auxiliary agents are mixed in advance with the B liquid in advance, and the two liquids are mixed, foamed and cured using an apparatus described later. It is. The foaming agent, catalyst, and surfactant are preferably mixed in the B liquid. However, in some cases, the foaming agent, the catalyst, and the surfactant are mixed in the A liquid, or the respective components are not mixed until just before the urethanization reaction, and three or more kinds are mixed. Sometimes handled as a raw material liquid.

  In the production of polyurethane foam, any apparatus can be used as long as the liquid A and the liquid B can be mixed uniformly. For example, small mixer, low pressure or high pressure foaming machine for injection foaming, low pressure or high pressure foaming machine for slab foaming, low pressure or high pressure foaming machine for continuous line, spraying work For example, a spray foaming machine can be used. In addition, when manufacturing a polyurethane foam, each liquid temperature of A liquid and B liquid is normally adjusted to 10-60 degreeC.

  In the polyurethane foam of the present invention, an appropriate face material can be provided on one side or both sides as required. As the face material, for example, paper, wood, gypsum board, resin, aluminum foil, steel plate and the like are used.

  Hereinafter, specific embodiments of the present invention will be described in more detail by way of examples. However, the present invention is not limited by these examples unless it exceeds the gist.

<Synthesis of polyol>
Polyester polyol (A) was synthesized by a known method. Table 1 shows the composition of the raw carboxylic acid component and the alcohol component, the polymerization inhibitor, the acid value, the hydroxyl value, the viscosity, and the water content, using the obtained polyols as polyols 1 to 6. The physical property evaluation method of the polyester polyol (A) is shown in Table 2.

<Hydrolysis test>
Using the polyols 1 to 6 synthesized earlier, test solutions were prepared with the formulations shown in Table 3, and the acid values immediately after adjustment and after storage at 80 ° C. for 18 hours were compared. The results are shown in Table-3. The catalyst No. 1 Kao Raiser No. 1 manufactured by Kao Corporation 1 was used.

<Preparation of premix solution>
A premix solution was prepared according to the formulation shown in Table 4. In addition, Table 5 shows the raw materials used for these formulations.

<Manufacture of polyurethane foam>
Under the conditions shown in Table 6, a predetermined amount of Millionate MR-200 manufactured by Nippon Polyurethane Industry Co., Ltd. was taken as a premix solution and a polyisocyanate solution described in Table 4 and mixed at high speed with an electric mixer, and then steel plates on the upper and lower surfaces. The face material was poured into a prepared mold and clamped to prepare a polyurethane foam steel sheet face material sandwich panel. The isocyanate index was 300.

  The obtained polyurethane foam steel sheet face material sandwich panel was cut into a 99 × 99 mm central portion to create a test piece, and the flame resistance was evaluated by a cone calorie test. The corn calorie test was based on ISO5660-1 (2002), the test time was 20 minutes (non-combustible), and pass / fail was determined according to the criteria in Table 7, and the results are shown in Table 4. In addition, the evaluation standard in the corn calorie test was set to “pass” when all the conditions shown in Table 7 were satisfied.

  From the above results, the following are mainly clear.

(1) In Table 1, polyols 1 to 5 using a polymerization inhibitor have a storage stability of 6 months or more, whereas polyol-6 not using a polymerization inhibitor is thickened by polymerization. .
(2) In Table 3, Examples 1-4 using the polyester polyol of the present invention have a small increase in acid value due to hydrolysis, but Comparative Example 1, which was not used, has a large increase in acid value. In Comparative Example 2 where no polymerization inhibitor was used, the increase in acid value was small.
(3) In Table 3, Examples 5-8 using the polyester polyol of the present invention passed the corn calorie test, while Comparative Example 3 not used failed. Moreover, the corn calorie test is also passed about the comparative example 4 which did not use a polymerization inhibitor.
(4) It can be seen that the polyester polyol of the present invention has high storage stability and hydrolysis resistance, and the polyurethane foam using the polyester polyol has a desired flame retardancy even when a polyol stored for a long time is used.

Claims (7)

A polyurethane foam obtained using at least a polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and a polymerization inhibitor as a raw material,
(A) A part of the polyol is a polyester polyol (A) obtained by an esterification reaction of an alcohol component and a carboxylic acid component,
(B) As the carboxylic acid component used in the polyester polyol (A), fumaric acid and / or maleic acid is 10 mol% or more based on the total carboxylic acid component in the polyester polyol (A), and the side chain as the alcohol component. The diol having an alkyl group is used in an amount of 10 mol% or more based on the total alcohol components in the polyester polyol (A),
(C) containing 1 to 10,000 ppm by mass of the polymerization inhibitor relative to the polyester polyol (A),
Polyurethane foam characterized by that.   The aromatic polyester polyol (B) (however, excluding the polyester polyol (A)) is further used as a part of the polyol in an amount of 10 to 90 parts by weight based on 100 parts by weight of the polyol. The polyurethane foam described in 1. A method for producing a polyurethane foam using at least a polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and a polymerization inhibitor as raw materials,
(A) A part of the polyol is a polyester polyol (A) obtained by an esterification reaction of an alcohol component and a carboxylic acid component,
(B) As the carboxylic acid component used in the polyester polyol (A), fumaric acid and / or maleic acid is 10 mol% or more based on the total carboxylic acid component in the polyester polyol (A), and the side chain as the alcohol component. The diol having an alkyl group is used in an amount of 10 mol% or more based on the total alcohol components in the polyester polyol (A),
(C) containing 1 to 10,000 ppm by mass of the polymerization inhibitor relative to the polyester polyol (A),
A process for producing a polyurethane foam, characterized in that   The aromatic polyester polyol (B) (excluding the polyester polyol (A)) is further used as a part of the polyol in an amount of 10 to 90 parts by weight based on 100 parts by weight of the polyol. A process for producing a polyurethane foam as described in 1.   The method for producing a polyurethane foam according to claim 3 or 4, wherein a foaming agent having an ozone depletion coefficient of 0.1 or less is used.   The method for producing a polyurethane foam according to claim 3 or 4, wherein at least one selected from a hydrofluoroolefin-based blowing agent, a hydrocarbon-based blowing agent or water is used as the blowing agent.   7. The method for producing a polyurethane foam according to claim 3, wherein polymeric MDI is used as the polyisocyanate.