JP2012214786A - Method for producing soft polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem wherein the burning rate of foam is increased to worsen the combustibility of foam due to a decrease in the amount of material to be burnt if the foam is made low in density.SOLUTION: This method for producing soft polyurethane foam includes: reacting an active hydrogen component (A) and an organic polyisocyanate component (B) in the presence of a foaming agent (C), a urethanation catalyst (D) and a foam stabilizer (E), wherein (A) contains, as essential components, specific polyols (a1), (a2), (a3), (a4) and (a5) having the specific number-average number of functional groups, specific hydroxyl values, etc., and based on the weight of (A), the content of (a1) is 10-60 wt.%, the content of (a2) is 10-60 wt.%, the content of (a3) is 5-40 wt.%, the content of a polymer of a vinyl monomer (v) is 5-20 wt.%, the content of (a4) is 0.5-5 wt.%, and the content of (a5) is 0.1-1 wt.%.

Description

  The present invention relates to a method for producing a flexible polyurethane foam, and more particularly to a method for producing a flexible polyurethane foam suitable for uses such as a cushion for a vehicle seat.

  Conventionally, flexible polyurethane foams have been widely used in cushion materials for automobiles and the like, taking advantage of their excellent cushioning properties. In recent years, there has been a demand for lower density foams for the purpose of reducing costs. In order to meet the demand for lower density, the amount of water used as a foaming agent tends to increase further. Increasing the amount of water used (Non-Patent Document 1, etc.) is effective in reducing the density of the flexible foam in order to increase the amount of generated carbon dioxide gas. This causes a decrease in foam hardness, and further deteriorates strain characteristics and durability characteristics. As a specific technique for improving the hardness of the flexible foam, there is a method of increasing the amount of the crosslinking agent used for blending (Non-Patent Document 1), etc., but in such a method, the elongation and tear strength of the flexible foam are increased. There remains a problem such as insufficient mechanical properties, and a flexible foam that maintains mechanical properties even when the hardness is improved is desired.

Keiji Iwata, “Polyurethane Resin Handbook”, published by Nikkan Kogyo, published on September 25, 1987

  However, when the density of the foam is reduced, the amount of combustibles is reduced, so that the foam combustion speed is increased and the foam combustibility is deteriorated.

The present inventors diligently studied to solve this problem, and found a method for producing a flexible polyurethane foam having a low density and excellent flame retardancy by combining a polyol having a specific structure and an organic polyisocyanate. The present invention has been completed.
That is, the present invention is a soft product obtained by reacting an active hydrogen component (A) and an organic polyisocyanate component (B) in the presence of a foaming agent (C), a urethanization catalyst (D), and a foam stabilizer (E). A method for producing a polyurethane foam, wherein (A) contains the following polyols (a1), (a2), (a3), (a4) and (a5) as essential components, and based on the weight of (A), The content of (a1) is 10 to 60% by weight, the content of (a2) is 10 to 60% by weight, the content of (a3) is 5 to 40% by weight, and the content of the vinyl monomer (v) polymer 5 to 20% by weight, (a4) content of 0.5 to 5% by weight, and (a5) content of 0.1 to 1% by weight; Flexible polyurethane foam; and this flexible urethane foam Seat cushion material for a vehicle composed of beam; a.
Polyol (a1): Number average functional group number is 2 to 4, hydroxyl value is 20 to 40 mg KOH / g, oxyethylene is added to the terminal, and the content of terminal oxyethylene unit is 5 to 25% by weight Polyoxyethylene polyoxypropylene polyol in which the average addition mole number x of ethylene oxide per active hydrogen and the primary OH conversion rate y (%) of the terminal hydroxyl group satisfy the relationship of the following formula (1).
^{y <42.0x 0.47 (1-x} / 41) (1)
Polyol (a2): Number average functional group number is 2 to 4, hydroxyl value is 20 to 40 mg KOH / g, oxyethylene is added to the terminal, and the content of terminal oxyethylene unit is 5 to 15% by weight Polyoxyethylene polyoxypropylene polyol in which the average addition mole number x of ethylene oxide per active hydrogen and the primary OH conversion rate y (%) of the terminal hydroxyl group satisfy the relationship of the following formula (2).
y ≧ 42.0x ^0.47 (1-x / 41) (2)
Polyol (a3): a polyoxyalkylene polyol (a6) having a number average functional group number of 2 to 4, a hydroxyl value of 20 to 60 mg KOH / g, and having oxypropylene added at the terminal and / or oxyethylene at the terminal Is obtained by polymerizing vinyl monomer (v) in the presence of a radical polymerization initiator in polyoxyethylene polyoxypropylene polyol (a7) to which is added, and based on the weight of (a3), vinyl monomer (v ) Is a polymer whose content is 25 to 60% by weight, 10 to 100% by weight of (v) is styrene, and the volume average particle diameter (R) of the polymer particles is 0.9 μm or less. Combined polyol.
Polyol (a4): an active hydrogen atom-containing compound or an active hydrogen atom-containing compound having a number average functional group number of 2 to 8 and a hydroxyl value of 300 to 2000 mgKOH / g, an alkylene oxide having 2 and / or 3 carbon atoms A polyol obtained by addition.
Polyol (a5): Number average functional group number is 2 to 8, hydroxyl value is 20 to 130 mgKOH / g, carbon number of oxyalkylene group is 2 and 3, and content of oxyethylene unit is 50 to 80 Polyoxyalkylene polyol which is weight%.

  According to the method for producing a flexible polyurethane foam of the present invention, it is possible to obtain a flexible polyurethane foam having a low density and excellent in flame retardancy as compared with the conventional method.

In the present invention, the primary OH conversion rate of the terminal hydroxyl group is determined by ¹ H-NMR method after the sample is pre-treated in advance for esterification. Details of the ¹ H-NMR method will be specifically described below.
<Sample preparation method>
About 30 mg of a measurement sample is weighed into a sample tube for ¹ H-NMR having a diameter of 5 mm, and about 0.5 ml of deuterated solvent is added and dissolved. Thereafter, about 0.1 ml of trifluoroacetic anhydride is added, and the mixture is allowed to stand at 25 ° C. for about 5 minutes.
Here, the deuterated solvent is deuterated chloroform, deuterated toluene, deuterated dimethyl sulfoxide, deuterated dimethylformamide, or the like, and a solvent that can be dissolved in the sample is appropriately selected.

<NMR measurement>
¹ H-NMR measurement is performed under normal conditions.
<Calculation method of primary OH ratio of terminal hydroxyl group>
The signal derived from the methylene group to which the primary hydroxyl group is bonded is observed at around 4.3 ppm, and the signal derived from the methine group to which the secondary hydroxyl group is bonded is observed at around 5.2 ppm. Is calculated by the following equation [2].
Primary OH conversion rate (%) = [r / (2 + 2s)] × 100 [2]
However,
r: integrated value of a signal derived from a methylene group having a primary hydroxyl group bonded thereto around 4.3 ppm s: an integrated value of a signal derived from a methine group having a secondary hydroxyl group bonded thereto in the vicinity of 5.2 ppm.

  The active hydrogen component (A) used in the method for producing the flexible polyurethane foam of the present invention contains the polyols (a1), (a2), (a3), (a4) and (a5).

  Specific examples of polyols {(a1), (a2), (a4) and (a5) and (a6) and (a7)} include divalent to octavalent active hydrogen-containing compounds (for example, polyhydric alcohols, amines, Examples thereof include compounds having a structure in which an alkylene oxide (hereinafter abbreviated as AO) is added to a polyhydric phenol, a polycarboxylic acid, and a mixture thereof.

  Examples of the polyhydric alcohol include C2-C20 dihydric alcohols {aliphatic diols (ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc. Alkylene glycols) and alicyclic diols (cycloalkylene glycols such as cyclohexanediol and cyclohexanedimethanol)}; trihydric alcohols having 3 to 20 carbon atoms {aliphatic triols (glycerin, trimethylolpropane, trimethylolethane and hexanetriol) Alkanetriols such as 4 to 8 carbon number polyhydric alcohols {aliphatic polyols (pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, dipentaerythritol, etc.) Ol and their or intramolecular alkanetriol or intermolecular dehydration product; and sucrose, glucose, mannose, and fructose and sugar and their derivatives such as methyl glucoside}.

Examples of amines include alkanolamines, polyamines, and monoamines.
Examples of the alkanolamine include mono-, di- and tri-alkanolamines having 2 to 20 carbon atoms (for example, monoethanolamine, diethanolamine, triethanolamine and isopropanolamine).
As a polyamine (the number of primary and secondary amino groups: 2 to 8), as an aliphatic amine, an alkylenediamine having 2 to 6 carbon atoms (for example, ethylenediamine, propylenediamine and hexamethylenediamine), 4 to 20 carbon atoms. Polyalkylene polyamines (dialkylene triamine having 2 to 6 carbon atoms in the alkylene group to hexaalkylene heptamine, for example, diethylenetriamine and triethylenetetramine).
Also, aromatic polyamines having 6 to 20 carbon atoms (for example, phenylenediamine, tolylenediamine, xylylenediamine, diethyltoluenediamine, methylenedianiline and diphenyletherdiamine); alicyclic polyamines having 4 to 20 carbon atoms (for example, Isophoronediamine, cyclohexylenediamine, and dicyclohexylmethanediamine); heterocyclic polyamines having 4 to 20 carbon atoms (for example, piperazine and aminoethylpiperazine) and the like.
As monoamine, ammonia; as aliphatic amine, alkylamine having 1 to 20 carbon atoms (for example, n-butylamine and octylamine); aromatic monoamine having 6 to 20 carbon atoms (for example, aniline and toluidine); -20 alicyclic monoamine (for example, cyclohexylamine); C4-C20 heterocyclic monoamine (for example, piperidine) and the like.

  Polyvalent (2-8 valent) phenols include monocyclic polyphenols such as pyrogallol, hydroquinone and phloroglucin; bisphenols such as bisphenol A, bisphenol F and bisphenol sulfone; condensates of phenol and formaldehyde (novolaks); Examples include polyphenols described in Japanese Patent No. 3265641.

Examples of the polycarboxylic acid include aliphatic polycarboxylic acids having 4 to 18 carbon atoms (succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, etc.), and aromatic polycarboxylic acids having 8 to 18 carbon atoms (phthalic acid, Terephthalic acid, isophthalic acid, trimellitic acid, etc.) and mixtures of two or more thereof.
Two or more of these active hydrogen-containing compounds may be used in combination. Of these, polyhydric alcohols are preferred.

  As the AO added to the active hydrogen-containing compound, propylene oxide (hereinafter abbreviated as PO) and ethylene oxide (hereinafter abbreviated as EO) are preferable. AO preferably contains only these, but other AO may be used in combination within a range of 10% by weight or less (particularly 5% by weight or less) in AO. Other AOs are preferably those having 4 to 8 carbon atoms, such as 1,2-, 1,3-, 1,4- and 2,3-butylene oxide and styrene oxide. Also good.

  In the present invention, the polyol (a1) has a number average functional group number of 2 to 4, a hydroxyl value of 20 to 40 mgKOH / g, oxyethylene added to the terminal, and a content of terminal oxyethylene unit. It is a polyoxyethylene polyoxypropylene polyol which is 5 to 25% by weight. (A1) may use 2 or more types together.

The number average functional group number of (a1) is 2-4, preferably 3-4. Even if the number of functional groups outside this range is included, the number average functional group number may be 2 to 4 (the same applies to the number average functional group number of other polyols). In the present invention, the number of functional groups of the polyol is considered to be the same as the number of functional groups of the starting material.
When the number average functional group number of (a1) is less than 2, the curing time becomes long and the productivity is lowered, and when it exceeds 4, the elongation property of the foam is lowered.

The hydroxyl value (mgKOH / g) of (a1) is 20 to 40, preferably 22 to 39, and more preferably 23 to 38. If the hydroxyl value is less than 20, the foam hardness decreases, and if it exceeds 40, the foam has more closed cells and the foam tends to shrink.
In addition, the hydroxyl value in this invention is measured by the method prescribed | regulated to JISK0070 (1992 edition).

The content (% by weight) of the terminal oxyethylene unit (hereinafter referred to as EO unit) of (a1) is 5 to 25, preferably 6 to 23, more preferably 7 to 22. . The content (% by weight) of the internal EO unit in (a1) is preferably 3 or less, more preferably 0.
If the content of the terminal EO unit is less than 5, the foam is insufficiently cured immediately before the end of foaming and the foam tends to collapse, and if the content of the terminal EO unit exceeds 25, the foam has more closed cells and the foam shrinks. It becomes easy.

The polyol (a1) is a polyoxyethylene polyoxypropylene polyol in which the average addition mole number x of ethylene oxide per active hydrogen and the primary OH conversion rate y (%) of the terminal hydroxyl group satisfy the relationship of the following formula (1) It is.
^{y <42.0x 0.47 (1-x} / 41) (1)

Examples of the polyol (a1) include compounds having a structure in which AO is added to divalent to tetravalent compounds among the active hydrogen-containing compounds, and two or more kinds may be used in combination.
The AO preferably contains only PO and EO, but the other AO mentioned above may preferably contain 10% by weight or less (particularly 5% by weight or less) in the AO. As a method for adding PO and EO, block addition in the order of PO and EO is preferable. The catalyst used at the time of AO addition may be a commonly used catalyst such as a basic catalyst such as potassium hydroxide.

In the present invention, the polyol (a2) has a number average functional group number of 2 to 4, a hydroxyl value of 20 to 40 mgKOH / g, oxyethylene added to the terminal, and a content of terminal oxyethylene unit. Polyoxyethylene poly having an average addition mole number x of ethylene oxide per active hydrogen of 5 to 15% by weight and a primary OH conversion rate y (%) of the terminal hydroxyl group satisfying the relationship of the following formula (2) Oxypropylene polyol.
y ≧ 42.0x ^0.47 (1-x / 41) (2)

  The number average functional group number of the polyol (a2) is 2 to 4, preferably 3 to 4. When the number average functional group number is less than 2, the compression set is lowered, and when it exceeds 4, the elongation physical properties are lowered.

  The hydroxyl value (mgKOH / g) of (a2) is 20 to 40, preferably 22 to 39, more preferably 23 to 38. When the hydroxyl value is less than 20, the hardness of the foam is lowered, and when it exceeds 40, the elongation property is lowered.

  The content (% by weight) of terminal EO in (a2) is 5 to 15, preferably 6 to 14. The content (% by weight) of the internal EO unit in (a2) is preferably 3 or less, more preferably 0. When the content of the terminal EO unit is less than 5, curing immediately before the end of foaming is insufficient and the foam tends to collapse. When the content of the terminal EO unit exceeds 15, the closed cells increase and the foam tends to shrink.

Further, (a2) indicates that the average addition mole number x of ethylene oxide per active hydrogen and the primary OH conversion rate y satisfy the relationship of the following formula (2), preferably the relationship of the following formula (2 ′), Preferably, the relationship of the following formula (2 ″) is satisfied.
y ≧ 42.0x ^0.47 (1-x / 41) (2)
y ≧ 42.5x ^0.47 (1-x / 41) (2 ′)
y ≧ 43.0x ^0.47 (1-x / 41) (2 ″)
In addition, as a range of x, what is necessary is just in the range used as content of said EO unit, However, Preferably it is 0.1-12, More preferably, it is 1-10.
The above formula (2) is obtained in the same addition form using a polyol obtained by adding EO after terminal PO addition using a catalyst (α) described later and an alkali catalyst such as potassium hydroxide usually used. In order to distinguish from the polyol to be obtained, it is obtained by experiment. That is, (a2) obtained using (α) satisfies the relationship of formula (2), whereas the polyol obtained using an alkali catalyst does not satisfy the relationship of formula (2), that is, The relationship of Formula (1) is satisfied.
If (a2) does not satisfy the formula (2), the curing rate of the foam is lowered.

Examples of the polyol (a2) used in the present invention include compounds having a structure in which AO is added to the divalent to tetravalent compounds among the active hydrogen-containing compounds by a method described later. Good.
AO is PO and EO. AO preferably contains only these, but may be an adduct in which other AO is used in combination within a range of 10% by weight or less (particularly 5% by weight or less) in AO.
As an addition format of AO including PO and EO, a block addition in the order of PO and EO is preferable.

  Examples of a method for obtaining this polyol (a2) include a method of adding AO to the active hydrogen-containing compound in the order of PO and EO in the presence of a specific catalyst (α). When a basic catalyst such as potassium hydroxide usually used for AO addition is used, it is very difficult to obtain a polyol satisfying the formula (2) with a content of terminal EO units of 5 to 15% by weight. .

  (Α) is used at the time of PO addition, but it is not always necessary to use it at all stages of PO addition. After adding a part of PO in the presence of other commonly used catalysts described later, only (α) ) May be used to add the remaining PO.

Examples of (α) include those described in JP-A No. 2000-344881. Specifically, boron other than BF ₃ is bonded to a fluorine atom, a (substituted) phenyl group and / or a tertiary alkyl group. Or an aluminum compound such as triphenylborane, diphenyl-t-butylborane, tri (t-butyl) borane, triphenylaluminum, diphenyl-t-butylaluminum, tri (t-butyl) aluminum, tris (pentafluorophenyl) borane Bis (pentafluorophenyl) -t-butylborane, tris (pentafluorophenyl) aluminum, bis (pentafluorophenyl) -t-butylaluminum and the like.

  Among these, preferred are triphenylborane, triphenylaluminum, tris (pentafluorophenyl) borane and tris (pentafluorophenyl) aluminum, and more preferred are tris (pentafluorophenyl) borane and tris (pentafluoro). Phenyl) aluminum.

  The addition conditions of AO may be the same as the method described in the above publication, and for example, preferably 0.0001 to 10% by weight, more preferably 0.001 to 1% by weight with respect to the ring-opening polymer to be formed. The above catalyst is used, and the reaction is preferably performed at 0 to 250 ° C, more preferably 20 to 180 ° C.

The polyol (a2) can be obtained by further adding EO to the above PO adduct. When the catalyst (α) is used, the primary OH conversion rate of the terminal hydroxyl group of the polyol before EO addition is usually as large as 40% or more (preferably 60% or more, more preferably 70% or more). The primary OH conversion rate of the terminal hydroxyl group can be increased by the amount used. In addition, the catalyst used for the EO addition may be the catalyst (α) as it is or may be replaced with another catalyst that is usually used.
Other catalysts include basic catalysts such as sodium hydroxide, potassium hydroxide, cesium hydroxide, potassium carbonate and triethylenediamine; acid catalysts such as boron trifluoride, tin chloride, triethylaluminum and heteropolyacid; zinc hexacyano Cobaltate; phosphazene compounds and the like. Of these, basic catalysts are preferred. Although the usage-amount of a catalyst is not specifically limited, Preferably it is 0.0001 to 10 weight% with respect to the polymer to produce | generate, More preferably, it is 0.001 to 1 weight%.

In the present invention, the polyol (a3) polymerizes the vinyl monomer (v) in the presence of a radical polymerization initiator in the following polyoxyalkylene polyol (a6) and / or the following polyoxyethylene polyoxypropylene polyol (a7). The polymer content of the vinyl monomer (v) is 25 to 60% by weight based on the weight of (a3), and the volume average particle diameter (R) of the polymer particles is 0.9 μm. It is a polymer polyol that is:
Polyoxyalkylene polyol (a6): a polyoxyalkylene polyol having a number average functional group number of 2 to 4, a hydroxyl value of 20 to 60 mgKOH / g, and having an oxypropylene added to the terminal, polyoxyethylene polyoxypropylene polyol (A7): a polyoxyethylene polyoxypropylene polyol having a number average functional group number of 2 to 4, a hydroxyl value of 20 to 60 mgKOH / g, and an oxyethylene added to the terminal

  The polyol (a3) used in the present invention can be produced by polymerizing the vinyl monomer (v) in the presence of a radical polymerization initiator in (a6) and / or (a7) by an ordinary method. Specific examples of the polymerization method include those described in US Pat. No. 3,383,351, Japanese Examined Patent Publication No. 39-25737, and the like.

  As the radical polymerization initiator, those that generate a free radical to initiate polymerization can be used, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile). ), Azo compounds such as 2,2′-azobis (2-methylbutyronitrile); organic peroxides such as dibenzoyl peroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide and persuccinic acid; Examples thereof include inorganic peroxides such as persulfate and perborate. In addition, these can use 2 or more types together.

As vinyl monomer (v), aromatic vinyl monomer (v1), unsaturated nitrile (v2), (meth) acrylic acid ester (v3), other vinyl monomers (v4), and two or more of these Of the mixture.
Examples of (v1) include styrene, α-methylstyrene, hydroxystyrene, chlorostyrene, and the like.
Examples of (v2) include acrylonitrile and methacrylonitrile.
(V3) includes those composed of C, H and O atoms, for example, (meth) acrylic acid alkyl ester (alkyl group having 1 to 24 carbon atoms) [for example, methyl (meth) acrylate, butyl (meta ) Acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, eicosyl (meth) acrylate, docosyl (meth) acrylate], hydroxyalkyl (2 to 5 carbon atoms) (meth) acrylate [for example, Hydroxyethyl (meth) acrylate] and hydroxypolyoxyalkylene mono (meth) acrylate [for example, an alkylene group having 2 to 4 carbon atoms and a polyoxyalkylene chain having a number average molecular weight of 200 to 1000].

(V4) includes ethylenically unsaturated carboxylic acids and derivatives thereof, specifically (meth) acrylic acid, (meth) acrylamide, etc .; aliphatic or alicyclic hydrocarbon monomers, specifically alkenes ( Ethylene, propylene, norbornene, etc.), alkadienes (butadiene, etc.); fluorinated vinyl monomers, specifically fluorine-containing (meth) acrylates (perfluorooctylethyl methacrylate, perfluorooctylethyl acrylate, etc.), etc .; chlorine -Based vinyl monomers, specifically vinylidene chloride, etc .; nitrogen-containing vinyl monomers other than those mentioned above, specifically nitrogen-containing (meth) acrylates (diaminoethyl methacrylate, morpholinoethyl methacrylate, etc.); and vinyl-modified silicones Etc.
Preferred among these (v) are (v1) and (v2), particularly styrene and / or acrylonitrile.

The weight ratio of (v1), (v2), (v3) and (v4) in the vinyl monomer (v) can be changed according to the required physical properties of the polyurethane and is not particularly limited. An example is as follows.
The total of (v1) and (v2) is preferably 50 to 100% by weight, more preferably 90 to 100% by weight. The weight ratio of (v1) and (v2) is not particularly limited, but is preferably 0/100 to 90/10. (V3) is preferably 0 to 50% by weight, more preferably 0 to 20% by weight. (V4) is preferably 0 to 10% by weight, more preferably 0 to 5% by weight.
In addition to these monofunctional monomers, a small amount (preferably 0.05 to 1% by weight) of a bifunctional or higher (preferably 2 to 8 functional) polyfunctional vinyl monomer (v5) is used in (v). As a result, the strength of the polymer can be further improved. Examples of (v5) include divinylbenzene, ethylene di (meth) acrylate, polyalkylene (alkylene group having 2 to 8 carbon atoms, degree of polymerization: 2 to 10) glycol di (meth) acrylate, pentaerythritol triallyl ether, Examples include methylolpropane tri (meth) acrylate.

  The styrene content in (v) is 10 to 100% by weight based on the weight of (v), preferably 10 to 90% by weight, more preferably 26 to 80% from the viewpoint of flame retardancy of the foam. % By weight.

  In the polyol (a3), the content of the polymer (v) is 25 to 60% by weight, preferably 26 to 50% by weight, based on the weight of (a3). When the content of the polymer is 25% by weight or more, sufficient foam hardness can be exhibited, and when it is 60% by weight or less, the viscosity of (a3) is low and handling is easy.

  In (a3), the volume average particle system (R) of the polymer particles is 0.9 μm or less, and preferably from 0.1 to 0.8 μm, more preferably from 0.1 to 0.8 μm, from the viewpoint of mechanical properties of the foam. 0.7 μm. If it exceeds 0.9 μm, the formability of the foam is deteriorated.

The number average functional group number of (a6) and (a7) is 2-4, preferably 3-4. If it is less than 2, foam hardness and impact resilience are poor, and if it exceeds 4, foam elongation is poor.
The hydroxyl value of (a6) and (a7) is 20 to 60 mgKOH / g, and preferably 22 to 59 mgKOH / g, more preferably 23 to 58 mgKOH / g, from the viewpoint of mechanical properties of the foam. When it is less than 20 mgKOH / g, the foam hardness is deteriorated, and when it exceeds 60 mgKOH / g, the wet heat compression set is deteriorated.

  As (a6), for example, an alkylene oxide having 2 to 8 or more carbon atoms (hereinafter abbreviated as AO) is added to the polyhydric alcohol having 2 to 4 hydroxyl groups, and then PO is added to the terminal. And a polyoxyalkylene polyoxypropylene polyol having a hydroxyl value of 20 to 60 mgKOH / g to which is added. (A6) may use 2 or more types together.

  Examples of (a7) include, for example, a polyoxyethylene having a hydroxyl value of 20 to 60 mgKOH / g in which PO is added to the polyhydric alcohol having 2 to 4 hydroxyl groups and EO is added to the terminal. Examples include polyoxypropylene polyol. (A7) may use 2 or more types together.

  In the present invention, the polyol (a4) has an active hydrogen atom-containing compound or an active hydrogen atom-containing compound having a number average functional group number of 2 to 8 and a hydroxyl value of 300 to 2000 mgKOH / g. 3 is a polyol obtained by adding 3 alkylene oxides.

As the active hydrogen atom-containing compound of (a4), among the above-mentioned compounds, active hydrogen atom-containing compounds such as amines having 2-8 valent alcohols, 2-8 valent phenols and 2-8 active hydrogens, etc. Can be mentioned.
In (a4), examples of the alkylene oxide having 2 and / or 3 carbon atoms include EO and PO. Examples of the active hydrogen atom-containing compound include those mentioned above.

The number average functional group number of (a4) is 2 to 8, and preferably 2 to 7 and more preferably 3 to 6 from the viewpoints of moldability and mechanical properties of the foam. If it is less than 2, the mechanical properties of the foam deteriorate, and if it exceeds 8, the elongation of the foam deteriorates.
The hydroxyl value of (a4) is 300 to 2000 mgKOH / g, and preferably 400 to 1900 mgKOH / g, more preferably 450 to 1850 mgKOH / g, from the viewpoint of mechanical properties of the foam. If it is less than 300 mgKOH / g, the hardness of the foam is deteriorated, and if it exceeds 2000 mgKOH / g, the elongation of the foam is deteriorated.

  In the present invention, the polyol (a5) has a number average functional group number of 2 to 8, a hydroxyl value of 20 to 130 mgKOH / g, an oxyalkylene group having 2 and 3 carbon atoms, and containing an oxyethylene unit. A polyoxyalkylene polyol having an amount of 50 to 80% by weight.

Examples of the polyol (a5) used in the present invention include compounds having a structure in which AO is added to divalent to octavalent compounds among the active hydrogen-containing compounds, and two or more kinds may be used in combination.
AO containing only PO and EO is preferable, but other AO may be contained within a range of 10% or less (particularly 5% or less) in AO.
The addition format of PO and EO may be PO or EO block addition or random addition, but random addition is preferable.

  The number average functional group number of a polyol (a5) is 2-8, Preferably it is 3-4. When the number average functional group number of (a5) is less than 2, the curing time becomes long and the productivity is lowered, and when it exceeds 8, the elongation property of the foam is lowered.

  The hydroxyl value (mgKOH / g) of (a5) is 20 to 130, preferably 21 to 120, and more preferably 22 to 115. If the hydroxyl value is less than 20, the foam hardness decreases. If it exceeds 130, the foam has more closed cells and the foam tends to shrink.

  The content of the EO unit in (a5) is 50 to 80% by weight, preferably 55 to 78% by weight, and more preferably 60 to 76% by weight. When the EO unit content is less than 50%, the curing time becomes long, and when it exceeds 80%, the foam has more closed cells and the foam tends to shrink.

  Among the polyols (a5), a polyoxyalkylene polyol having an oxyethylene unit content of 50 to 80% by weight and being an EO / PO random adduct is preferred from the viewpoint of foam breathability.

In the present invention, in the polyol component (A), the contents (% by weight) of (a1), (a2), (a3), (a4) and (a5) are (a1) based on the weight of (A). ) Content is 10-60, (a2) content is 10-60, (a3) content is 5-40, (a4) content is 0.5-5, (a5) content Is 0.1 to 1, preferably (a1) is 10 to 59.4, (a2) is 10 to 59.4, (a3) is 5 to 39, and (a4) is 0.5 to 4.5. , (A5) is 0.1 to 1.0, and more preferably (a1) is 10 to 58.0%, (a2) is 10 to 58.0%, (a3) is 10 to 38%, (A4) is 0.5 to 4.0%, (a5) is 0.2 to 1.0%, and (a1) is preferably 10 to 57.0% and (a2) is 10 to 57. 0% (A3) is 15 to 37% (a4) is from 0.5 to 4.5%, a is 0.3~1.0% (a5).
When (a1) is 10 or more, the stretched physical properties of the foam are good, and when it is 60 or less, the hardness of the foam is not insufficient. If (a2) is 10 or more, the hardness of the foam will not be insufficient, and if it is 60 or less, the elongation physical properties will not decrease. When (a3) is 5 or more, the hardness of the foam does not become insufficient, and when it is 40 or less, the elongation physical properties do not deteriorate. When (a4) is 0.5 or more, the hardness of the foam is not insufficient, and when it is 5 or less, closed cells do not increase. When (a5) is 0.1 or more, the number of closed cells does not increase, and when it is 1 or less, the curing time does not become long.

  In the present invention, in the polyol component (A), the content of the polymer of the vinyl monomer (v) is 5 to 20% by weight based on the weight of (A), and the hardness of the foam and compression set From the viewpoint of rate, it is preferably 5 to 15% by weight, more preferably 6 to 13% by weight.

  As the organic polyisocyanate component (B) in the present invention, an organic polyisocyanate used when producing a conventional flexible polyurethane foam can be used. For reasons such as improvement of productivity and improvement of work environment, (B) is based on the weight of (B), and is based on the weight of (B), at least one kind selected from diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and their modified products. The content of isocyanate (hereinafter abbreviated as MDI) is preferably 50% by weight or more, and more preferably 60 to 90% by weight. Examples of the modified products include urethane-modified products, carbodiimide-modified products, allophanate-modified products, urea-modified products, burette-modified products, isocyanurate-modified products, and oxazolidone-modified products. The content of the other polyisocyanate is preferably 50% by weight or less, more preferably 10 to 40% by weight, and the other polyisocyanate is preferably tolylene diisocyanate.

  As the foaming agent (C) in the present invention, water, hydrogen atom-containing halogenated hydrocarbon, low boiling point hydrocarbon, liquefied carbon dioxide gas, or the like can be used. Two or more kinds may be used in combination, but preferably water is used, particularly preferably only water is used alone. In the case of using only water alone as (C), the amount of water used is preferably 4.5 to 5.5 parts by weight per 100 parts by weight of the active hydrogen component (A) from the viewpoint of moldability and density of the foam. More preferably, it is 4.7 to 5.3 parts by weight. The amount of water used in combination with other foaming agents is preferably from 3.0 to 5.5 parts by weight, more preferably from 2 to 4 based on the weight of (A), from the viewpoint of moldability of the foam. 0.0 part by weight.

  Examples of the hydrogen atom-containing halogenated hydrocarbon include HCFC (hydrochlorofluorocarbon) type (for example, HCFC-123, HCFC-141b, HCFC-22, and HCFC-142b); HFC (hydrofluorocarbon) type (for example, HFC- 134a, HFC-152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, and HFC-365mfc). From the viewpoint of flame retardancy, preferred among these are HCFC-141b, HFC-134a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC-365mfc and mixtures of two or more thereof. is there. The amount of hydrogen atom-containing halogenated hydrocarbon used is preferably 50 parts by weight or less, more preferably 5 to 45 parts by weight per 100 parts by weight of (A) from the viewpoint of moldability and density of the foam. .

The low boiling point hydrocarbon is a hydrocarbon having a boiling point of −5 to 50 ° C., and specific examples thereof include butane, pentane, cyclopentane, and mixtures thereof. The amount of low boiling point hydrocarbon used is preferably 40 parts by weight or less, more preferably 5 to 30 parts by weight, per 100 parts by weight of (A), from the viewpoint of formability and density of the foam.
The amount of liquefied carbon dioxide used is preferably 30 parts by weight or less, more preferably 25 parts by weight or less, from 100 parts by weight of (A), from the viewpoint of moldability and density of the foam.

  As the catalyst (D) in the present invention, a conventional catalyst for promoting the urethanization reaction can be used. Examples thereof include triethylenediamine, bis (N, N-dimethylamino-2-ethyl) ether, N, N, N ′. , N′-tetramethylhexamethylenediamine and other tertiary amines and carboxylic acid salts thereof; carboxylic acid metal salts such as potassium acetate, potassium octylate and stannous octoate; and organometallic compounds such as dibutyltin dilaurate. The amount of the catalyst (D) used is preferably 0.01 to 5 parts by weight, more preferably 0.2 to 100 parts by weight with respect to 100 parts by weight of the active hydrogen component (A), from the viewpoint of foam moldability and mechanical properties. 2 parts by weight.

  As the foam stabilizer (E) in the production method of the present invention, those used in the production of conventional polyurethane foams can be used. As an example, a dimethylsiloxane foam stabilizer [for example, “manufactured by Toray Dow Corning Co., Ltd.” SRX-253 "etc.], polyether-modified dimethylsiloxane foam stabilizers (for example," L-3640 "manufactured by Momentive Performance Materials LLC," SF-2962 "manufactured by Toray Dow Corning Co., Ltd.) Silicone foam stabilizers such as “SZ-1346”, “SZ-1327”, “TEGOSTAB B8738LF2”, “TEGOSTAB B8719LF”, “TEGOSTAB B8715LF2”, etc., manufactured by Goldschmidt, and the like. The amount of the foam stabilizer (E) used is preferably 0.5 to 3 parts by weight, more preferably 0.8 to 2 parts, from the viewpoint of moldability of the foam with respect to 100 parts by weight of the active hydrogen component (A). 0.0 part by weight.

  In the production method of the present invention, if necessary, other additives as described below may be used and reacted in the presence thereof. For example, colorants (dyes, pigments), flame retardants (phosphate esters, halogenated phosphate esters, etc.), anti-aging agents (triazoles, benzophenones, etc.), antioxidants (hindered phenols, hindered amines) Etc.) can be reacted in the presence of usual auxiliary components. With respect to the amount of these auxiliary components used relative to 100 parts by weight of the active hydrogen component (A), the colorant is preferably 1 part by weight or less. The flame retardant is preferably 5 parts by weight or less, more preferably 2 parts by weight or less. The anti-aging agent is preferably 1 part by weight or less, more preferably 0.5 part by weight or less. The antioxidant is preferably 1 part by weight or less, more preferably 0.01 to 0.5 part by weight.

  In the production method of the present invention, the isocyanate index [(NCO group / active hydrogen atom-containing group equivalent ratio) × 100] (hereinafter referred to as an index) in the production of polyurethane is 70 to 125 from the viewpoint of moldability. More preferably, it is 75-120, Most preferably, it is 80-115.

  The flexible polyurethane foam of the present invention can be obtained by an ordinary method for producing a flexible urethane foam using the above raw materials as essential raw materials. An example of the manufacturing method is as follows. First, a predetermined amount of the active hydrogen component (A), the foaming agent (C), the catalyst (D), the foam stabilizer (E), and other additives as necessary are mixed. Next, this mixture and the organic polyisocyanate component (B) are temperature-controlled at 25 ° C. using a polyurethane foaming machine (for example, “high pressure foaming machine” manufactured by PEC) or a stirrer, and then rapidly mixed. The obtained mixed solution (foaming stock solution) is poured into a sealed or open mold (made of metal or resin) adjusted to 65 ° C. to perform a urethanization reaction, and after being cured for a predetermined time, it is demolded. A flexible polyurethane foam can be obtained. In addition, a flexible polyurethane foam can be obtained even by continuous foaming. The present invention is particularly suitable as a method for producing a mold foam.

The flexible polyurethane foam of the present invention preferably has a core density of 25 to 35 kg / m ³ , more preferably 27 to 33 kg / m ³ . When the core density is 25 kg / m ³ or more, the wet heat compressive stress strain is further improved, and when it is 35 kg / m ³ or less, the foam breathability is further improved. The core density can be measured based on the method of JIS K6401 relating to the measurement of physical properties of polyurethane foam.

  The vehicle seat cushion material composed of the flexible polyurethane foam of the present invention can be obtained by a normal method for producing a vehicle seat cushion material using the above-mentioned raw materials as essential raw materials. An example of the manufacturing method is as follows. First, a predetermined amount of the active hydrogen component (A), the foaming agent (C), the catalyst (D), the foam stabilizer (E) and other additives as necessary are mixed. Next, this mixture and the organic polyisocyanate component (B) are temperature-controlled at 25 ° C. using a polyurethane foaming machine (for example, “high pressure foaming machine” manufactured by PEC) or a stirrer, and then rapidly mixed. The obtained mixed solution (foaming stock solution) is poured into a sealed or open mold (made of metal or resin) for vehicle seats adjusted to 65 ° C. to cause urethanization reaction, and after curing for a predetermined time By removing the mold, a flexible polyurethane foam for a vehicle seat cushion material can be obtained. Moreover, even if it foams continuously, the flexible polyurethane foam for vehicle seat cushion materials can be obtained. The present invention is particularly suitable as a method for producing a mold foam. The vehicle seat cushion material composed of the flexible urethane foam of the present invention has a feature of good flame retardancy.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by this. In Examples and Comparative Examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively, unless otherwise specified.

[Examples 1 to 13 and Comparative Examples 1 to 5]
A predetermined amount of organic polyisocyanate B is added to the number of parts of the polyol premix (mixture of components other than organic polyisocyanate) shown in Table 1 so as to have an NCO index of 100. After stirring at 4000 rpm for 6 seconds, the mixture was poured into a 300 mm (length) × 300 mm (width) × 100 mm (height) aluminum mold whose temperature was adjusted to 65 ° C., and molded with a curing time of 5 minutes.
Table 1 shows the measurement results such as physical property values of each foam. The core density is a density measured by cutting out from the center of the foam into a size of 100 mm × 100 mm × 50 mm.

The polyurethane foam raw materials in Examples and Comparative Examples are as follows.
(1) Polyol a1: Polyether obtained by adding 67.4 mol of PO to 1 mol of glycerin using potassium hydroxide as a catalyst, then adding 22.7 mol of EO as a block, and removing potassium hydroxide by a conventional method Polyol. Hydroxyl value = 33.7, EO unit content = 20.0%.
(2) Polyol a2: 8 mol of PO was added to 1 mol of pentaerythritol in the same manner as in Example 1 of JP-A-2006-063344 using tris (pentafluorophenyl) borane as a catalyst. Polyether polyol obtained by adding 10.4 mol of EO as a catalyst and removing potassium hydroxide by a conventional method. Hydroxyl value = 39.4, EO unit content = 8.0%, primary OH ratio = 84%.
(3) Polyol a6: 4 mol of PO and 3.4 mol of EO are randomly added to 1 mol of glycerin using potassium hydroxide as a catalyst, and then 2.6 mol of PO is added in blocks, and potassium hydroxide is added by a conventional method. A polyether polyol obtained by removal. Hydroxyl value = 56.1, EO unit content = 5.0%.
(4) Polyol a7: Polyester obtained by adding 101.2 mol of PO to 1 mol of pentaerythritol using potassium hydroxide as a catalyst, then adding 20.2 mol of EO in a block, and removing potassium hydroxide by a conventional method Ether polyol. Hydroxyl value = 32.1, EO unit content = 12.0%.
(5) Polyol a3-1: A polymer polyol obtained by copolymerizing styrene and acrylonitrile with styrene / acrylonitrile = 70/30 (weight ratio) in polyol a3 / a4 = 96/4 (weight ratio). (Polymer content 46%), hydroxyl value = 31.0, volume average particle diameter (R) of polymer particles is 0.6 μm.
(6) Polyol a3-2: Copolymerized styrene and acrylonitrile with styrene / acrylonitrile = 30/70 (weight ratio) in polyol a3 / a4 = 80/20 (polymer content 32%), hydroxyl group Value = 24.9, and the volume average particle diameter (R) of the polymer particles is 0.4 μm.
(7) Polyol a4-1: A polyether polyol obtained by adding 8.7 mol of PO to 1 mol of sorbitol using potassium hydroxide as a catalyst and removing potassium hydroxide by a conventional method. Hydroxyl value = 490, EO unit content = 0%.
(8) Polyol a4-2: Glycerin. Hydroxyl value = 1829.
(9) Polyol a4-3: triethanolamine. Hydroxyl value = 1130.
(10) Polyol a4-4: A polyether polyol obtained by adding 2.45 mol of EO to 1 mol of glycerin using potassium hydroxide as a catalyst. Hydroxyl value = 841, EO unit content = 54%.
(11) Polyol a4-5: A polyether polyol obtained by adding 2 mol of EO to 1 mol of sorbitol and removing potassium hydroxide by a conventional method. Hydroxyl value 1247.
(12) Polyol a5-1: 1 mol of EO is added to 1 mol of glycerol using potassium hydroxide as a catalyst, and then 14.5 mol of PO and 56.0 mol of EO are randomly added, and potassium hydroxide is removed by a conventional method. A polyether polyol obtained as described above. Hydroxyl value = 49, EO unit content = 72.5%.

Foaming agent (C): Water catalyst (D-1): Ethylene glycol solution of triethylenediamine [“TEDA-L33” manufactured by Tosoh Corporation]
Catalyst (D-2): 70% dipropylene glycol solution of bis (dimethylaminoethyl) ether [“TOYOCAT ET” manufactured by Tosoh Corporation]
Foam stabilizer (E-1): Goldschmidt “TEGOSTAB B8738LF2”
Foam stabilizer (E-2): “SZ-1346” manufactured by Toray Dow Corning
Foam stabilizer (E-3): “L-3640” manufactured by Momentive
Isocyanate (B): TDI-80 / crude MDI = 20/80 (weight ratio), NCO% = 32.0

In Table 1, the burning rate: SE indicates that it is self-digesting (the flame ignited on the test piece disappears without propagating).
<Test example>
<1>: Core density (kg / m ³ )
<2>: wet heat compression set (%)
<3>: Flame resistance (combustion rate)
<1> and <2> are based on JIS K6400 (1997 edition). <3> complied with US automobile safety standards (MVSS-302). The flame retardancy is preferably as the combustion speed is slow (or does not combust).

From the results of Table 1 produced with the same core density, it can be seen that the wet heat compression set is small in the example and is superior to the comparative example. Moreover, in an Example, it turns out that a combustion rate is small and a flame retardance is superior to a comparative example.
On the other hand, a comparative example is inferior in a combustion rate or a wet heat compression set rate.
From these results, it is understood that a flexible polyurethane foam having low density and good flame retardancy is obtained only in the examples of the present invention.

The flexible polyurethane foam of the present invention is a flexible urethane foam having good flammability in a specific low core density range.
Due to the above effects, the polyurethane foam of the present invention is useful as a sheet material. It is particularly useful as a cushion material for vehicle seats.

Claims (4)

A process for producing a flexible polyurethane foam obtained by reacting an active hydrogen component (A) and an organic polyisocyanate component (B) in the presence of a foaming agent (C), a urethanization catalyst (D) and a foam stabilizer (E) And (A) contains the following polyols (a1), (a2), (a3), (a4) and (a5) as essential components, and contains (a1) based on the weight of (A) The amount is 10 to 60% by weight, the content of (a2) is 10 to 60% by weight, the content of (a3) is 5 to 40% by weight, and the content of the polymer of vinyl monomer (v) is 5 to 20% by weight. %, The content of (a4) is 0.5 to 5% by weight, and the content of (a5) is 0.1 to 1% by weight.
Polyol (a1): Number average functional group number is 2 to 4, hydroxyl value is 20 to 40 mg KOH / g, oxyethylene is added to the terminal, and the content of terminal oxyethylene unit is 5 to 25% by weight Polyoxyethylene polyoxypropylene polyol in which the average addition mole number x of ethylene oxide per active hydrogen and the primary OH conversion rate y (%) of the terminal hydroxyl group satisfy the relationship of the following formula (1).
^{y <42.0x 0.47 (1-x} / 41) (1)
Polyol (a2): Number average functional group number is 2 to 4, hydroxyl value is 20 to 40 mg KOH / g, oxyethylene is added to the terminal, and the content of terminal oxyethylene unit is 5 to 15% by weight Polyoxyethylene polyoxypropylene polyol in which the average addition mole number x of ethylene oxide per active hydrogen and the primary OH conversion rate y (%) of the terminal hydroxyl group satisfy the relationship of the following formula (2).
y ≧ 42.0x ^0.47 (1-x / 41) (2)
Polyol (a3): a polyoxyalkylene polyol (a6) having a number average functional group number of 2 to 4, a hydroxyl value of 20 to 60 mg KOH / g, and having oxypropylene added at the terminal and / or oxyethylene at the terminal Is obtained by polymerizing vinyl monomer (v) in the presence of a radical polymerization initiator in polyoxyethylene polyoxypropylene polyol (a7) to which is added, and based on the weight of (a3), vinyl monomer (v ) Is a polymer whose content is 25 to 60% by weight, 10 to 100% by weight of (v) is styrene, and the volume average particle diameter (R) of the polymer particles is 0.9 μm or less. Combined polyol.
Polyol (a4): an active hydrogen atom-containing compound or an active hydrogen atom-containing compound having a number average functional group number of 2 to 8 and a hydroxyl value of 300 to 2000 mgKOH / g, an alkylene oxide having 2 and / or 3 carbon atoms A polyol obtained by addition.
Polyol (a5): Number average functional group number is 2 to 8, hydroxyl value is 20 to 130 mgKOH / g, carbon number of oxyalkylene group is 2 and 3, and content of oxyethylene unit is 50 to 80 Polyoxyalkylene polyol which is weight%. A flexible polyurethane foam obtained by the production method according to claim 1. The flexible polyurethane foam according to claim 2, wherein the core density is 25 to 35 kg / m ³ . The vehicle seat cushion material comprised from the flexible polyurethane foam of Claim 2 or 3.