JP5157117B2 - Flexible polyurethane foam and method for producing the same - Google Patents

Description

  The present invention relates to a flexible polyurethane foam and a method for producing the same.

A polyurethane foam produced by polymerizing a polyol and an isocyanate is used, for example, as a cushioning material such as furniture represented by a sofa, and usually has a cell number of 30 to 50 / 25.4 mm . Among them, a flexible polyurethane foam having a cell number of 30 / 25.4 mm or less is called “coarse cell foam”, and the coarse cell foam is used for various filters, highly breathable mattresses, pillows, sponge scourers, and the like. Yes.
Among the coarse cell foams, those having a uniform number of cells are particularly preferable. For functional filters, those having a cell number of 20 / 25.4 mm or less are more preferable from the viewpoint of pressure loss and dust collection efficiency. It is demanded as something.

  As a method for producing the coarse cell foam, a cell structure is controlled by using a polyester polyol having a high viscosity, a thickener is added to the polyether polyol to increase the viscosity of the polyol component system, and A method of manufacturing a coarse cell foam by adding a polysiloxane compound (see Patent Document 1) has been proposed.

Also, in a method for producing a flexible polyurethane foam comprising a polyol, a polyisocyanate, a foam stabilizer, a foaming agent, etc., a predetermined amount of drug is stirred and mixed in the mixing head so as to be almost uniform, and a mixing chamber at the time of mixing is mixed. There has been proposed a method for producing a coarse cell foam by setting the internal pressure to 1.5 to 2.5 kg / cm ² and the air injection amount to 50 to 1000 cc / min (see Patent Document 2).

In addition, as an example of producing a polyurethane foam using amino-modified silicone, a method for producing a polyurethane foam for abrasive sheets in which the cell diameter of the foam is widely distributed (see Patent Document 3), the surface friction resistance is small, And a method for providing an elastic member having fine cells (see Patent Document 4) and a method for producing a polyurethane having excellent moldability and appearance when molded by a reaction injection molding method (see Patent Document 5). Proposed.
Japanese Patent Laid-Open No. 60-219213 Japanese Patent Laid-Open No. 11-116717 JP 2004-75700 A JP 2002-187929 A JP 57-117524 A

However, in the method described in Patent Document 1, there is a limit to the reduction and uniformization of the number of cells in the flexible polyurethane foam. In addition, the use of high viscosity polyols or the addition of a thickener to the polyols handles the high viscosity polyol component system, which may deteriorate the workability.
In the method described in Patent Document 2, since the number of cells is controlled by setting machine conditions, there is a limit to equalizing the number of cells. Furthermore, since a facility capable of injecting air is essential, the manufacturing method is limited.
According to the method described in Patent Document 3, a foaming agent (water, inert gas, etc.) is not used during production, the specific gravity is 0.87, and the average number of cells is 390 to 635 cells / 25.4 mm. A polyurethane foam having a fine cell structure is obtained. However, the polyurethane foam is different from the coarse cell foam in terms of the number of cells, and the number of cells is non-uniform due to the large distribution of cell diameters, which is not suitable for functional filters. Appropriate.
Similarly, according to the method described in Patent Document 4, an elastic member having a fine cell structure with 50 to 200 cells / 25.4 mm is obtained. The elastic member is mainly used for a toner supply roller or the like for an image forming apparatus, and is different from the coarse cell foam in terms of the number of cells.
In addition, according to the method described in Patent Document 5, a flexible or semi-rigid polyurethane having a density of 1.0 to 1.15 g / cm ² and used for a bumper cover of an automobile or the like can be obtained. The polyurethane has a high density, is an ultrafine cell, and is inappropriate for a functional filter.

  Therefore, the present invention stably stabilizes a flexible polyurethane foam having coarse cells having a uniform number of cells without using a special polyol having a high viscosity and without being limited to mechanical conditions. Provide a method that can be manufactured.

The flexible polyurethane foam of the present invention comprises a polyoxyalkylene polyol having a hydroxyl value of 5 to 112 mgKOH / g and a polyisocyanate compound based on 100 parts by mass of a catalyst, a foaming agent and a foam stabilizer, and polyoxyalkylene polyol. In the presence of 0.001 to 1 part by mass of a compound represented by the following formula (1) and / or the following formula (2) having an amino equivalent of 100 to 100,000 g / mol: The number of cells is 30 / 25.4 mm or less.

However, in Formula (1), R ¹ Is an alkylene group having 1 to 10 carbon atoms and R ² Is an alkyl group having 1 to 10 carbon atoms, and k is an integer of 1 to 2000.
In the formula (2), m is an integer of 0 to 100; n is an integer of 1 to 2000; R ³ , R ⁴ And R ⁵ May be the same as or different from each other, each from a group consisting of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms having a nitrogen atom. A group to be selected (provided that when m is 0, R ³ Or R ⁵ At least one of them is a C1-C10 alkyl group which has a nitrogen atom, and when m is an integer of 1-100, R ³ , R ⁵ And m R ⁴ At least 1 is a C1-C10 alkyl group which has a nitrogen atom. ).

The polyoxyalkylene polyol preferably contains fine polymer particles.

Further, flexible polyurethane foams of the present invention, it is preferable core density of 15~50kg / ^{m 3.}

The flexible polyurethane foam of the present invention has coarse cells having a uniform number of cells.
According to the method for producing a flexible polyurethane foam of the present invention, a flexible polyurethane foam having coarse cells having a uniform number of cells can be stabilized without using a special polyol having a high viscosity and without being limited by mechanical conditions. Can be manufactured.

<Method for producing flexible polyurethane foam>
The method for producing a flexible polyurethane foam according to the present invention comprises reacting a polyoxyalkylene polyol having a hydroxyl value of 5 to 112 mgKOH / g with a polyisocyanate compound in the presence of a catalyst, a foaming agent and a foam stabilizer. In the method for producing a foam, the reaction is carried out in the presence of 0.001 to 1 part by mass of amino-modified silicone (E) with respect to 100 parts by mass of the polyoxyalkylene polyol.
As a method for producing the flexible polyurethane foam, for example, a polyisocyanate compound is added to a mixture of all raw materials other than the polyisocyanate compound so as to have an isocyanate index described later, and the mixture is stirred and mixed to prepare a reactive mixture. There is a method in which the mixture is injected into a mold or the like and foamed.
Hereinafter, an example of the method for producing the flexible polyurethane foam of the present invention will be described by dividing it into a step of preparing a reactive mixture and a foaming step.

[Step of preparing reactive mixture]
In this step, all raw materials other than the polyisocyanate compound (polyoxyalkylene polyol having a hydroxyl value of 5 to 112 mgKOH / g, amino-modified silicone (E), foam stabilizer, foaming agent, catalyst, crosslinking agent, other components) A reactive mixture is prepared by adding a polyisocyanate compound to the mixture (hereinafter sometimes referred to as a polyol system liquid) and stirring and mixing.

(Polyoxyalkylene polyol)
In the present invention, a polyoxyalkylene polyol having a hydroxyl value of 5 to 112 mgKOH / g is used. The polyoxyalkylene polyol preferably contains fine polymer particles.

  The hydroxyl value of the polyoxyalkylene polyol is 5 to 112 mgKOH / g, and particularly preferably 11.2 to 112 mgKOH / g. By setting the hydroxyl value to 5 mgKOH / g or more, collapse or the like can be suppressed, and a flexible polyurethane foam can be stably produced. By setting the hydroxyl value to 112 mgKOH / g or less, the flexibility of the obtained flexible polyurethane foam is improved. Excellent.

A polyoxyalkylene polyol having a hydroxyl value of 5 to 112 mgKOH / g is obtained, for example, by ring-opening polymerization of a cyclic ether in the presence of a polymerization catalyst using an active hydrogen compound having an average hydroxyl number of 2 to 6 as an initiator. be able to.
In the present invention, the “average number of hydroxyl groups” means the average number of active hydrogen atoms in the initiator. By setting the average number of hydroxyl groups to 2 or more, foam physical properties such as foam elongation, tensile strength, and dry heat compression set are improved. On the other hand, when the average number of hydroxyl groups is 6 or less, the produced flexible polyurethane foam does not become too hard, and foam physical properties such as elongation and tensile strength are improved.

Examples of the initiator include ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, diglycerin, dextrose, sucrose, Examples thereof include bisphenol A, and compounds obtained by adding a small amount of alkylene oxide to them.
The initiators may be used alone or in combination of two or more.
The average number of hydroxyl groups of the polyoxyalkylene polyol is the same as the average number of hydroxyl groups of the initiator used.

Examples of the polymerization catalyst include potassium compounds such as potassium hydroxide and potassium methoxide, alkali metal compounds such as cesium compounds such as cesium metal, cesium hydroxide, cesium carbonate, and cesium methoxide, or alkali metal hydroxides; Examples thereof include cationic polymerization catalysts such as rides, double metal cyanide complexes, and phosphazenium compounds. Among them, it is preferable to use a normal alkali catalyst such as potassium hydroxide, a cesium compound, or a double metal cyanide complex, and it is particularly preferable to use a double metal cyanide complex from the viewpoint of obtaining a polymer having a large molecular weight.
The polymerization catalyst may be used alone or in combination of two or more.

As the cyclic ether, an alkylene oxide having 2 or more carbon atoms is preferable, and specific examples include ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, and the like.
These cyclic ethers may be used alone or in combination of two or more.
In the present invention, it is particularly preferable to use ethylene oxide in combination with at least one selected from propylene oxide, 1,2-butylene oxide and 2,3-butylene oxide.

The polyoxyalkylene polyol may have an oxyethylene group at the terminal or inside thereof.
The polyoxyalkylene polyol having an oxyethylene group inside the polyoxyalkylene polyol includes, for example, an initiator, an alkylene oxide having 3 or more carbon atoms and ethylene oxide sequentially, or a mixture of an alkylene oxide and ethylene oxide having 3 or more carbon atoms. Can be obtained by ring-opening polymerization.
The polyoxyalkylene polyol having an oxyethylene group at the terminal of the polyoxyalkylene polyol can be obtained, for example, by ring-opening polymerization of an initiator and an alkylene oxide having 3 or more carbon atoms and then ring-opening polymerization of ethylene oxide. it can. In addition, the initiator, the alkylene oxide having 3 or more carbon atoms and the ethylene oxide are sequentially subjected to ring-opening polymerization of the alkylene oxide having 3 or more carbon atoms and the mixture of ethylene oxide, and then obtained by ring-opening polymerization of ethylene oxide. You can also.

In the polyoxyalkylene polyol, the molecular weight per hydroxyl group is preferably 500 or more, and particularly preferably 1000 to 10,000. By setting the molecular weight to 500 or more, the flexibility of the produced flexible polyurethane foam is excellent.
The molecular weight of the polyoxyalkylene polyol is a value calculated by the following formula using a hydroxyl value measured according to JIS K1557 (1970 edition).

  Molecular weight = (56100 × average number of hydroxyl groups of polyol) / hydroxyl value

In the present invention, the polyoxyalkylene polyol preferably contains fine polymer particles. By using a polyoxyalkylene polyol containing fine polymer particles, the resin strength is increased, collapse and the like are suppressed, and a flexible polyurethane foam can be stably produced.
The polyoxyalkylene polyol containing polymer fine particles (hereinafter sometimes referred to as polymer-dispersed polyol) contains polymer fine particles in a polyoxyalkylene polyol matrix.

The polymer of the polymer fine particles is preferably an addition polymerization polymer or a condensation polymerization polymer.
Specific examples of the addition polymerization polymer include homopolymers and copolymers obtained by polymerizing vinyl monomers such as acrylonitrile, styrene, methacrylic acid ester, and acrylic acid ester.
Specific examples of the polycondensation polymer include polyester, polyurea, polyurethane, and melamine resin.
You may use this polymer individually by 1 type or in combination of 2 or more types.
The content of the polymer fine particles in the polyoxyalkylene polyol is preferably 50 parts by mass or less, more preferably 3 to 45 parts by mass with respect to 100 parts by mass of the polyoxyalkylene polyol. By increasing the content of the polymer fine particles to 50 parts by mass or less, an increase in viscosity is suppressed.

(Amino-modified silicone (E))
In the present invention, amino-modified silicone (E) having a silicon atom and a nitrogen atom in the molecule (hereinafter sometimes referred to as component (E)) is used. In the present invention, the polyoxyalkylene polyol and the polyisocyanate compound are reacted with the catalyst, the foaming agent and the foam stabilizer in the presence of the component (E).
By using the component (E), the cell diameter becomes substantially uniform, and a coarse cell having a uniform number of cells is formed. The reason is presumed that by reacting in the presence of the component (E), bubbles formed by foaming are appropriately broken to facilitate the coalescence of the bubbles.

As the component (E), the amino equivalent is preferably 100 to 100,000 g / mol, and more preferably 1000 to 10,000 g / mol. By making the amino equivalent 100 g / mol or more, the effect of the present invention can be easily obtained. Further, the foam characteristics are improved. By setting the amino equivalent to 100000 g / mol or less, the component (E) can be present more stably without being separated in the polyol system liquid.
The amino equivalent can be determined by a general neutralization titration method. For example, it can be calculated using the neutralization titration method described in JIS K7245 (2000 edition).

  Specifically, the component (E) is preferably a compound represented by the formula (1) or the formula (2).

In the formula (1), R ¹ is an alkylene group having 1 to 10 carbon atoms, and may be linear or branched. Carbon number of this alkylene group is 1-10, it is preferable that it is 1-8, and it is more preferable that it is 1-5. Specific examples include a methylene group, an ethylene group, a propylene group, and a butylene group.
R ² is an alkyl group having 1 to 10 carbon atoms, and may be linear or branched. The alkyl group has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, and a butyl group. However, three R < ² > may mutually be same or different.
k is an integer of 1 to 2000, preferably an integer of 1 to 1500, and more preferably an integer of 1 to 1000. When k is in the range of 1 to 2000, foam foaming becomes more stable. However, the three k may be the same or different from each other.

In said Formula (2), m is an integer of 0-100, and it is preferable that it is an integer of 0-50. When m is in the range of 0 to 100, the foam can be stably foamed.
n is an integer of 1 to 2000, preferably an integer of 1 to 1500, and more preferably an integer of 1 to 1000. When n is in the range of 1 to 2000, foam foaming becomes more stable.

R ³ , R ^4, and R ⁵ may be the same or different from each other, and each have an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and 1 to 1 carbon atoms having a nitrogen atom. It is a group selected from the group consisting of 10 alkyl groups.
The alkyl group may be linear or branched. The alkyl group has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, and a butyl group.
The alkoxy group may be linear or branched. The alkoxy group has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. Specific examples include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

In the present invention, “an alkyl group having a nitrogen atom” means a group in which at least one hydrogen atom of an alkyl group is substituted with an amine.
The amine may be a primary amine, a secondary amine, or a tertiary amine. The primary amine is one in which one of the hydrogen atoms of the amine is substituted with an alkyl group in the “alkyl group having a nitrogen atom”. The secondary or tertiary amine is one further substituted with a hydrocarbon group other than the alkyl group (however, the hydrocarbon group may be further substituted with an amine). In that case, carbon atoms present in the hydrocarbon group are also included in the carbon number.
The alkyl group having a nitrogen atom may be linear or branched. The alkyl group has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms.
The number of nitrogen atoms of the alkyl group, that is, the number of amines as a substituent is preferably 1 to 3.
Specific examples of the alkyl group having a nitrogen atom include aminomethyl group, aminoethyl group, aminopropyl group, aminohexyl group, aminooctyl group, N, N-dimethylaminoethyl group, N, N-diethylaminoethyl group, N, N-dimethylaminopropyl group, N- (aminoethyl) aminopropyl group _{(-C 3 H 6 -NH-C} 2 H 4 -NH 2), N- (N '- ( aminoethyl) aminoethyl) amino And a propyl group (—C ₃ H ₆ —NH—C ₂ H ₄ —NH—C ₂ H ₄ —NH ₂ ) and the like.
Among them, an alkyl group having an active hydrogen atom bonded to a nitrogen atom, that is, substituted with a primary amine or a secondary amine, because it does not bleed out from the flexible urethane foam finally produced. Is preferred.

In the formula (2), when m is 0, an alkyl group having 1 to 10 carbon atoms and having at least one nitrogen atom in ^{R 3} or ^{R 5,} and more preferred form ^R 3, ^{R 5} together nitrogen It is a C1-C10 alkyl group which has an atom.
When m is an integer of 1 to 100, at least one of R ³ , R ^5, and m R ⁴ is a C 1-10 alkyl group having a nitrogen atom, and a more preferable embodiment is that R ⁴ is nitrogen. A C 1-10 alkyl group having an atom, R ³ , R ⁵ are any one of a C 1-10 alkyl group and a C 1-10 alkoxy group, or R ³ , R ⁴ and This is a case where two or more of R ⁵ are a C 1-10 alkyl group having a nitrogen atom.
However, when m is an integer of 2 or more, m R ^{4 s} may be the same as or different from each other.
The main chain composed of (m + n) siloxane units may be a block copolymer chain or a random copolymer chain.

The amino-modified silicone (E) may be used alone or in combination of two or more.
The usage-amount of amino-modified silicone (E) is 0.001-1 mass part with respect to 100 mass parts of polyoxyalkylene polyol, Preferably it is 0.01-1 mass part. The effect of this invention is acquired by setting it as 0.001 mass part or more. Further, the foam characteristics are improved. By setting it to 1 part by mass or less, foam stability at the time of foaming is improved.

(Foam stabilizer)
The foam stabilizer used in the present invention is preferably a silicone compound from the viewpoint of foam stability and the like. As a silicone type compound, the silicone type foam stabilizer normally used for a flexible polyurethane foam can be used.
One type of foam stabilizer may be used alone, or two or more types may be used in combination.
The amount of the foam stabilizer used is preferably 0.001 to 3 parts by mass with respect to 100 parts by mass of the polyoxyalkylene polyol.

(Foaming agent)
As a foaming agent used in this invention, water and an inert gas are mentioned as a suitable thing, for example.
Examples of the inert gas include air, nitrogen, carbon dioxide and the like.
Among the foaming agents, water is preferable.
A foaming agent may be used individually by 1 type, and may mix and use 2 or more types. Especially, it is preferable to use 1 or more types of foaming agents chosen from water and an inert gas, it is more preferable to use water, and it is especially preferable to use only water.
The amount of the blowing agent used is not particularly limited. For example, when only water is used, it is preferably 10 parts by mass or less, and 1.5 to 8 parts by mass with respect to 100 parts by mass of the polyoxyalkylene polyol. It is particularly preferred. Even when other foaming agents are used, an appropriate amount can be used according to the request such as the expansion ratio.

(catalyst)
As the catalyst used in the present invention, a catalyst that promotes the urethanization reaction can be used. For example, triethylenediamine, bis [(2-dimethylamino) ethyl] ether, N, N, N ′, N′-tetramethylhexamethylene Examples thereof include tertiary amines such as diamines, carboxylic acid metal salts such as potassium acetate and potassium 2-ethylhexanoate, and organometallic compounds such as dibutyltin dilaurate and stannous octoate.
A catalyst may be used individually by 1 type and may be used in mixture of 2 or more types. Among these, the combined use of an amine catalyst and a metal catalyst is preferable because of excellent production stability of an open flexible polyurethane foam. In that case, the mixing ratio of the amine catalyst and the metal catalyst is preferably 1/100 to 100/1, more preferably 1/10 to 10/1, in terms of mass ratio.
It is preferable that the usage-amount of a catalyst shall be 0.01-5 mass parts with respect to 100 mass parts of a polyoxyalkylene polyol.

(Crosslinking agent)
In the present invention, a crosslinking agent may be used. By using the crosslinking agent, the foamed physical properties such as tensile strength of the produced flexible polyurethane foam are excellent.
As the crosslinking agent, a polyol having an average number of hydroxyl groups of 2 to 8 and a hydroxyl value of 200 to 2000 mgKOH / g is preferable.
A crosslinking agent may be used individually by 1 type, and may mix and use 2 or more types.
The amount of the crosslinking agent used is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polyoxyalkylene polyol.

(Other ingredients)
In producing the flexible polyurethane foam of the present invention, an anti-aging agent such as an emulsifier, an antioxidant, an ultraviolet absorber, a filler such as calcium carbonate and barium sulfate, a flame retardant, a plasticizer, a colorant, and an anti-fungal agent. Various known additives and auxiliaries such as can be used as necessary.

(Polyisocyanate compound)
Examples of the polyisocyanate compound used in the present invention include 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), and crude tolylene diisocyanate (crude TDI). 4,4′-diphenylmethane diisocyanate (4,4′-MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 2,2′-diphenylmethane diisocyanate (2,2′-MDI), diphenylmethane Diisocyanate isomer mixtures (MDI), polymethylene polyphenyl isocyanate (crude MDI), toluidine diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, etc. Cyanate, carbodiimide-modified products of these diisocyanates, biuret modified products, dimers, and trimers, or prepolymers thereof and the like. Among these, 2,4-TDI, 2,6-TDI, crude TDI, or a mixture thereof is preferable.
This isocyanate compound may be used individually by 1 type, and may mix and use 2 or more types. Among them, a mixture of 2,4-TDI and 2,6-TDI at a mass ratio of 80/20 (abbreviated as 80 / 20-TDI), or a mixture of 65/35 at a mass ratio (65 / 35- Especially abbreviated as TDI).
The amount of the polyisocyanate compound used is a numerical value represented by 100 times the number of isocyanate groups with respect to the total number of active hydrogen atoms such as polyoxyalkylene polyol and water (usually, the numerical value is referred to as “isocyanate index”) of 80 to 80. 120 is preferable, and 85 to 115 is particularly preferable.

(Method of foaming flexible polyurethane foam)
As a method of foaming a flexible polyurethane foam, for example, a reactive mixture is injected into a closed mold, the reactive mixture is foamed (molding method), and the reactive mixture is injected into a mold or the like in an open system. And foaming (slab method). Of these, the slab method is preferred because the effects of the present invention are easily obtained.
Specifically, it can be performed by a known method such as a one-shot method, a semi-prepolymer method, or a prepolymer method.
Moreover, the manufacturing apparatus normally used can be used for manufacture of a flexible polyurethane foam.

<Soft polyurethane foam>
The flexible polyurethane foam of the present invention is produced by the method for producing a flexible polyurethane foam.

Preferably the core density of the soft quality polyurethane foam is 15~50kg / ^{m 3,} more preferably 15~40kg / ^{m 3.} When the core density is 15 kg / m ³ or more, collapse or the like is suppressed, and a flexible polyurethane foam can be stably produced. When it is 50 kg / m ³ or less, the resin component constituting the flexible polyurethane foam becomes an appropriate amount, and a foam of a coarse cell is easily obtained.
In the present invention, the “core density” means the density of the central portion of the flexible polyurethane foam and excluding the surface layer portion.
The core density can be adjusted by the amount of foaming agent used. For example, when only water is used as the foaming agent, the core density of the flexible polyurethane foam is 15 by setting the amount of water used to 1.5 to 8 parts by mass with respect to 100 parts by mass of the polyoxyalkylene polyol. It can be adjusted to ˜50 kg / m ³ .
The core density can be measured by a method based on JIS K6400 (1997 edition).

The number of cells of the flexible polyurethane foam is preferably 30 / 25.4 mm or less, more preferably 20 / 25.4 mm or less, and the lower limit is preferably 5 / 25.4 mm or more. . When the number of cells is 30 / 25.4 mm or less, particularly 20 / 25.4 mm or less, it can be used as a functional filter having high dust collection efficiency with low pressure loss.
The number of cells can be adjusted by the amount of the amino-modified silicone (E) used. In the present invention, the component (E) is used within a range of 0.001 to 1 part by mass with respect to 100 parts by mass of the polyoxyalkylene polyol. can do.
The number of cells can be measured by a method based on JIS K6400 (1997 edition).

As described above, the flexible polyurethane foam of the present invention has coarse cells having a uniform number of cells.
In addition, according to the method for producing a flexible polyurethane foam of the present invention, a flexible polyurethane foam having coarse cells with a uniform number of cells without using a special polyol having a high viscosity and without being restricted by mechanical conditions. Can be manufactured stably.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these examples.
Tables 2 and 3 show the blending composition at the time of producing the flexible polyurethane foam and the foam physical properties of the obtained flexible polyurethane foam, respectively.
In Tables 2 and 3, Examples 1-2 represent Examples, and Examples 3-5 represent Comparative Examples, respectively.
In the blend composition, the unit of the amount of each raw material used is “part by mass”. The amount of catalyst C1, catalyst C2, silicone foam stabilizer D1, amino-modified silicone E1, amino-modified silicone E2, and foaming agent F indicates the value for 100 parts by mass of the polyoxyalkylene polyol (polyol A1, polyol B1), respectively. .
Moreover, the usage-amount of polyisocyanate G shows an isocyanate index.

(Raw materials used)
Polyol A1: A polyoxypropylene polyol having an average number of functional groups of 3 and a hydroxyl value of 56 mgKOH / g, obtained by ring-opening addition polymerization of propylene oxide using glycerol as an initiator using a potassium hydroxide catalyst.
Polyol B1: In a polyether polyol obtained by ring-opening addition polymerization of a mixture of ethylene oxide and propylene oxide (10:90 mass ratio) using glycerin as an initiator using a potassium hydroxide catalyst, acrylonitrile and styrene are mixed. A polymer fine particle-dispersed polyol having a content of polymer fine particles obtained by copolymerization of 42% by mass, an average number of functional groups of 3, and a hydroxyl value of 31 mgKOH / g.

Catalyst C1: Dipropylene glycol solution of triethylenediamine (manufactured by Tosoh Corporation, trade name: TEDA-L33).
Catalyst C2: Tin octylate (manufactured by Air Products and Chemicals, trade name: DABCO T-9).

  Foam stabilizer D1: Silicone foam stabilizer (manufactured by Dow Corning Toray, trade name: L-5740M).

Amino-modified silicones E1 to E2: Compounds shown in Table 1. However, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , k, n, and m represent the symbols in the formulas (1) and (2), respectively.

Foaming agent F: water.
Polyisocyanate G: TDI-80 (mixture of 80/20 by mass ratio of 2,4-TDI and 2,6-TDI: 80 / 20-TDI), isocyanate group content 48.3% by mass (Nippon Polyurethane Industry) Product name: Coronate T-80).

(Method for producing flexible polyurethane foam)
Among the raw materials shown in Tables 2 and 3, the liquid temperature of the mixture of all raw materials other than polyisocyanate G (polyol system liquid) was adjusted to 22 ° C. ± 1 ° C., and isocyanate G was adjusted to 22 ° C. ± 1 ° C.
Next, polyisocyanate G was added to the polyol system solution so as to have an isocyanate index shown in Tables 2 and 3, and the mixture was stirred and mixed for 5 seconds with a high-speed mixer (2000 revolutions per minute) to prepare a reactive mixture.
Thereafter, the reactive mixture was poured into a mold in which a vinyl sheet was laid in a wooden box of 250 mm in length, width and height each having an open top at room temperature to produce a flexible polyurethane foam.

(Evaluation of physical properties of foam)
The flexible polyurethane foam produced by the above production method is taken out of the wooden box and left in a room adjusted to room temperature (23 ° C.) and humidity 50% for 24 hours or more, and then various foam physical properties shown below are measured. It was. The measurement results are shown in Tables 2 and 3.

Foam physical properties are: core density (unit: kg / m ³ ), number of cells (unit: pieces / 25.4 mm ), 25% hardness (ILD) (unit: N / 314 cm ² ), tear strength (unit: N / cm), tensile strength (unit: kPa), elongation (unit:%), and dry heat compression set (unit:%), respectively. Each foam physical property was evaluated by a method based on JIS K6400 (1997 edition).

  From the results shown in Tables 2 and 3, Examples 1 and 2 using specific amounts of the amino-modified silicone of the present invention are limited to mechanical conditions without using special polyols with high viscosity. It was confirmed that a flexible polyurethane foam having coarse cells with a uniform number of cells could be produced stably.

In addition, the flexible polyurethane foams of Examples 1 and 2 can be used for functional filters having high dust collection efficiency with low pressure loss because the number of cells falls within the range of 20 cells / 25.4 mm or less. Was confirmed.
Moreover, since the dry polyurethane compression set which is a parameter | index of durability was as small as 5% or less, it has confirmed that durability was also favorable for the flexible polyurethane foam of Examples 1-2.

The flexible polyurethane foam of the present invention is an air filter for transportation equipment, an engine filter for industrial machinery, a temperature control filter for OA equipment, an air conditioner filter for household appliances, and a high breathability for furniture and clothing. It can be used for mattresses, pillows, microphone covers for acoustic products, cosmetic puffs for hygiene products, sponge scrubbing for daily use, and hydroponic culture media for agricultural and fishery materials.
The flexible polyurethane foam of the present invention is particularly suitable as a functional filter foam that requires low pressure loss and high dust collection efficiency.

Claims (3)

A polyoxyalkylene polyol having a hydroxyl value of 5 to 112 mgKOH / g;
A polyisocyanate compound,
The compound represented by the following formula (1) and / or the following formula (2) with respect to 100 parts by mass of the catalyst, the foaming agent and the foam stabilizer, and the polyoxyalkylene polyol, having an amino equivalent of 100 to 100000 g / mol. A flexible polyurethane foam produced by reacting in the presence of 0.001 to 1 part by mass of amino-modified silicone (E),
A flexible polyurethane foam characterized in that the number of cells is 30 / 25.4 mm or less.

However, in the formula (1), ^{R 1} is an alkylene group having 1 to 10 carbon atoms, ^{R 2} is an alkyl group having 1 to 10 carbon atoms, k is an integer of 1 to 2,000.
In the formula (2), m is an integer of 0 to 100; n is an integer of 1 to 2000; R ³ , R ⁴ and R ⁵ may be the same or different from each other, A group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms having a nitrogen atom (however, when m is 0, R ³ or When at least one of R ^{5 is} a C 1-10 alkyl group having a nitrogen atom and m is an integer of 1-100, at least one of R ³ , R ⁵ and m R ⁴ is It is a C1-C10 alkyl group having a nitrogen atom.) Flexible polyurethane Form of claim 1, wherein the polyoxyalkylene polyol contains fine polymer particles. The flexible polyurethane foam according to claim 1 or 2 , wherein the core density is 15 to 50 kg / m ³ .