JP2002322235A - Method for producing soft polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing soft polyurethane foam using a small amount of TDI, having a low density and a high resilient elastic modulus, and excellent in mechanical strength. SOLUTION: This method for producing soft polyurethane foam is characterized by reacting (A) a polyol composition containing (a1), (a2) and (a3) as shown below, and (B) a polyisocyanate composition obtained by using (b1), (b2) and (b3) as shown below in the presence of (C) a catalyst, (D) a foaming agent and (E) a foam-adjusting agent. (A) the polyol composition: (a1): a polyetherpolyol having Mn 1,000-10,000, (a2): a polyetherpolyol having Mn 500-5,000, (a3): a polyetherpolyol having Mn 3,000-10,000 (B) the polyisocyanate composition: (b1): a polyetherpolyol having Mn 1,000-10,000, (b2): an MDI, (b3): a polymethylenepolyphenylenepolyisocyanate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a flexible polyurethane foam. More specifically, a flexible polyurethane foam having excellent working environment, low density, high elasticity, and excellent mechanical properties, and particularly suitable for use in an automobile seat cushion, a motorcycle saddle, a bicycle saddle, etc. in molding. The present invention relates to a method for producing a polyurethane foam.

[0002]

2. Description of the Related Art Flexible polyurethane foams are used in various fields such as cushioning materials for automobiles, furniture, carpets, etc., taking advantage of their excellent cushioning properties. A flexible polyurethane foam is produced by reacting a polyisocyanate composition and a polyol composition in the presence of a foaming agent, a catalyst, a foam stabilizer, and if necessary, other auxiliaries. This polyisocyanate composition has conventionally been tolylene diisocyanate (hereinafter abbreviated as TDI), but recently, diphenylmethane diisocyanate (hereinafter MDI) has been used.
DI) and a mixture of polymethylene polyphenylene polyisocyanate (hereinafter abbreviated as polymeric MDI)
And TDI are often used. As the polyol composition, a polyether polyol obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to an active hydrogen-containing substance is generally used as a main raw material.

For example, JP-A-5-25242 discloses an example in which an isocyanate (hereinafter abbreviated as NCO) group-terminated prepolymer comprising a specific isocyanate and a polyol is used for a flexible polyurethane foam.
Japanese Patent Application Laid-Open No. 8-12737 discloses an example in which an NCO-terminated prepolymer using a specific polyol is used for a flexible polyurethane foam.

[0004] In recent years, in the automobile industry, the use of springs in seat cushion components has been progressing as part of weight reduction of vehicles. In order to provide a cushioning feeling even without a spring, it is necessary to increase the elasticity of the flexible polyurethane foam used. For this reason, there is a demand for a flexible polyurethane foam having a high rebound resilience, good mechanical strength, and appropriate hardness.

However, TDI is more advantageous than MDI-based polyisocyanate for its high resilience of flexible polyurethane foam because of its structural characteristics. , TDI alone or a mixture of TDI and MDI polyisocyanates is used. T at this time
The DI ratio is generally 50 to 80% by mass.

[Problems to be solved by the invention]

[0006] However, TDI is specified as a specific chemical substance, and it is desirable to reduce the amount of use from the viewpoint of the working environment. However, in the conventional technology, in a composition in which the amount of TDI is reduced and the amount of MDI is increased, it is difficult to achieve both high rebound resilience and maintenance of mechanical strength, and it is excellent in cushion feeling and mechanical strength. High flexible polyurethane foam could not be obtained.

[0007]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a method for producing a flexible polyurethane foam which uses a small amount of TDI, has a low density, a high resilience and a high mechanical strength. As a result of intensive studies and studies, it has been found that a method for producing a flexible polyurethane foam using a polyisocyanate composition having a specific composition and a polyol composition having a specific composition can solve these problems, and have completed the present invention. .

That is, the present invention provides the following (1) to (6)
It is shown in. (1) A polyol composition (A) containing (a1), (a2) and (a3) shown below, and (b) shown below
1) reacting the polyisocyanate composition (B) obtained using (b2) and (b3) in the presence of a catalyst (C), a blowing agent (D), and a foam stabilizer (E). A method for producing a flexible polyurethane foam, characterized by: Polyol composition (A): (a1): a compound having two or more active hydrogens as an initiator, and a mixture of ethylene oxide and an alkylene oxide having 3 or more carbon atoms added randomly, the number average molecular weight being 1, 000-10,000 polyether polyol (a2): a polyether polyol having a number average molecular weight of 500-5,000, to which ethylene oxide is added using a compound having two or more active hydrogens as an initiator (a3): Using a compound having two or more active hydrogens as an initiator, an alkylene oxide having 3 or more carbon atoms is added, and ethylene oxide is further added to the terminal at 10 to 30% by mass. The number average molecular weight is 3,000 to 10, , 00
0 polyether polyol polyisocyanate composition (B): (b1): using a compound having two or more active hydrogens as an initiator, adding an alkylene oxide having 3 or more carbon atoms, and further adding ethylene oxide to the terminal at 5 ~ 30% by mass
The added number average molecular weight is 1,000 to 10,000
(B2): diphenylmethane diisocyanate having two isocyanate groups and two benzene rings each (b3): polymethylene polyphenylene polyisocyanate having three or more isocyanate groups and three or more benzene rings each

(2) The following (a1), (a2),
The polyol composition (A) containing (a3) and the polyisocyanate composition (B) obtained using the following (b1), (b2), (b3), and (b4) were used as a catalyst (C) ), A reaction in the presence of a foaming agent (D) and a foam stabilizer (E). Polyol composition (A): (a1): a compound having two or more active hydrogens as an initiator, and a mixture of ethylene oxide and an alkylene oxide having 3 or more carbon atoms added randomly, the number average molecular weight being 1, 000-10,000 polyether polyol (a2): a polyether polyol having a number average molecular weight of 500-5,000, to which ethylene oxide is added using a compound having two or more active hydrogens as an initiator (a3): Using a compound having two or more active hydrogens as an initiator, an alkylene oxide having 3 or more carbon atoms is added, and ethylene oxide is further added to the terminal at 10 to 30% by mass. The number average molecular weight is 3,000 to 10, , 00
0 polyether polyol polyisocyanate composition (B): (b1): using a compound having two or more active hydrogens as an initiator, adding an alkylene oxide having 3 or more carbon atoms, and further adding ethylene oxide to the terminal at 5 ~ 30% by mass
The added number average molecular weight is 1,000 to 10,000
(B2): diphenylmethane diisocyanate having two isocyanate groups and two benzene rings (b3): polymethylene polyphenylene polyisocyanate having three or more isocyanate groups and three or more benzene rings (b4): tolylene diisocyanate

(3) The content of (a1) in the polyol composition (A) is 1 to 30% by mass, and the content of (a2) is 3 to 60% by mass. The method for producing a flexible polyurethane foam according to 1) or 2).

(4) The method for producing a flexible polyurethane foam according to any one of the above (1) to (3), wherein the polyol composition (A) contains 1 to 25% by mass of polymer fine particles. .

(5) The polyether polyol (a3)
The method for producing a flexible polyurethane foam according to any one of the above (1) to (4), wherein the concentration of the monool therein is 25 mol% or less.

(6) The polyether polyol (b1)
The method for producing a flexible polyurethane foam according to any one of the above (1) to (5), wherein the concentration of the monool therein is 25 mol% or less.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The present invention reacts the following polyol composition (A) and the following polyisocyanate composition (B) in the presence of a catalyst (C), a foaming agent (D), and a foam stabilizer (E). A method for producing a flexible polyurethane foam.

First, the raw materials used in the present invention will be described. Polyol composition (A) used in the present invention
Contains (a1) to (a3) shown below.

(A1) is a polyether polyol obtained by randomly adding a mixture of ethylene oxide and an alkylene oxide having 3 or more carbon atoms to a compound containing two or more active hydrogens as an initiator. Examples of the “alkylene oxide having 3 or more carbon atoms” include propylene oxide, butylene oxide, and the like. In the present invention, propylene oxide is preferred. The number of functional groups of the initiator (a1) is preferably 2 to 8, and is preferably 2 to 8.
To 6 are more preferred. When the number of functional groups of the initiator is less than the lower limit, the resulting flexible polyurethane foam tends to have low strength and hardness due to low crosslinking density. If the upper limit is exceeded, the flexibility of the form is likely to be lost.

The content of the oxyethylene group in (a1) is 40% by mass or more and less than 100% by mass, preferably 45% by mass to 90% by mass. More preferably, it is 48 to 85% by mass. When the oxyethylene group content is less than the lower limit, the elastic performance of the foam tends to decrease, and it is difficult to produce a flexible polyurethane foam having a high rebound resilience.

The number average molecular weight of (a1) is 1,000 to 1.
000, preferably from 1,200 to 9.5
00 is more preferred. Most preferably, from 1,500
It is in the range of 9,000. When the number average molecular weight is less than the lower limit, the flexibility of the obtained foam is lost, and physical properties and elastic performance are likely to be deteriorated. When the number average molecular weight exceeds the upper limit, the hardness of the foam tends to decrease.

The initiator used to obtain (a1) includes ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 4-butanediol, 1,5-pentanediol, 2-methyl-1,5-
Pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, 2,2-diethyl-1,3-propane Diol,
2-n-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-n-
Hexadecane-1,2-ethylene glycol, 2-n-
Eicosan-1,2-ethylene glycol, 2-n-octacosan-1,2-ethylene glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, or an ethylene oxide or propylene oxide adduct of bisphenol A, hydrogenated Bisphenol A, 3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2-dimethylpropionate, trimethylolpropane, glycerin,
Low molecular weight polyols such as pentaerythritol, low molecular weight amines such as aniline, ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine And other low molecular weight amino alcohols. In the present invention, low molecular polyols are preferred.

(A2) is a polyether polyol to which ethylene oxide is added using a compound containing two or more active hydrogens as an initiator. Examples of the initiator include those used in the above (a1), and low molecular polyols are preferable. The number of functional groups of the initiator (a2) is
It is preferably from 2 to 8, and more preferably from 2 to 6.
When the number of functional groups of the initiator is less than the lower limit, the resulting flexible polyurethane foam tends to have low strength and hardness due to low crosslinking density. If the upper limit is exceeded, the flexibility of the form is likely to be lost.

The number average molecular weight of (a2) is from 500 to 5,0
00, preferably 550 to 4,000. Most preferably, it is in the range of 600 to 3,500. When the number average molecular weight is less than the lower limit, the flexibility of the obtained foam is lost, and the elastic performance tends to be reduced. When the number average molecular weight exceeds the upper limit, (a2) in the polyol composition (A)
Tends to cause phase separation, and the storage stability of the liquid tends to deteriorate.

(A3) is a polyether polyol obtained by adding a compound containing two or more active hydrogens as an initiator, adding an alkylene oxide having 3 or more carbon atoms, and further adding ethylene oxide to a terminal. Examples of the “alkylene oxide having 3 or more carbon atoms” include propylene oxide, butylene oxide, and the like.
In the present invention, propylene oxide is preferred.
Examples of the initiator include those used in the above (a1), and low molecular polyols are preferable. The number of functional groups of the initiator (a3) is preferably 2 to 8, and
6 or less is more preferable. When the number of functional groups of the initiator is less than the lower limit, the resulting flexible polyurethane foam tends to have low strength and hardness due to low crosslinking density. If the upper limit is exceeded, the flexibility of the form is likely to be lost.

In (a3), the amount of ethylene oxide added to the terminal (hereinafter abbreviated as EO chip amount) is 10 to 30.
%, Preferably 11 to 28% by mass, more preferably 12 to 26% by mass. When the amount of EO chips is less than the lower limit, the activity is reduced due to the decrease of the primary hydroxyl group at the molecular terminal, the stability of the cell is lost when the foam is formed, and the moldability tends to be reduced. When the amount of EO chips exceeds the upper limit, the affinity for water is improved and a colloid is easily formed, which causes an increase in the viscosity of the polyol composition (A).

The number average molecular weight of (a3) is from 3,000 to 1
000, preferably 3,500 to 9,500
It is. Most preferably, it is in the range of 4,000 to 9,000. When the number average molecular weight is less than the lower limit, the flexibility of the obtained foam is lost, and the elastic performance tends to be reduced. When the number average molecular weight exceeds the upper limit, the hardness of the obtained foam tends to decrease.

The content of (a1) in the polyol composition (A) is 1 to 30% by mass, preferably 3 to 25% by mass, more preferably 5 to 20% by mass. (A1)
When the amount is less than the lower limit, the air permeability and the rebound resilience of the obtained foam are likely to decrease. If it exceeds the upper limit, the stability of the cells when the foam is formed is reduced, and the moldability is likely to be deteriorated. Also, the hardness of the foam is apt to decrease.

The content of (a2) in the polyol composition (A) is 3 to 60% by mass, preferably 5 to 50% by mass, more preferably 7 to 40% by mass. (A2)
If the amount is less than the lower limit, the stability of the cells when the foam is formed is reduced, and the moldability is likely to be deteriorated. If it exceeds the upper limit, the air permeability and the rebound resilience of the obtained foam are likely to decrease. Also, the hardness of the foam is apt to decrease.

Furthermore, in the present invention, the polyol composition (A)
Polymer fine particles obtained by polymerization of one or more vinyl monomers or obtained by polymerization of a polyisocyanate and an active hydrogen group-containing compound having a molecular weight of 18 to 200 can be dispersed therein. The method of dispersing the polymer fine particles in (A) is a method of directly performing polymerization in polyether polyols (a1) to (a3),
Either of the methods of adding a polyol containing polymer fine particles polymerized in another polyol to (A) may be used. The content of the polymer fine particles in (A) thus obtained is 1 to 25% by mass, preferably 2 to 25% by mass.
It is 22% by mass, more preferably 3 to 20% by mass. When the content of the polymer fine particles exceeds the upper limit, the viscosity of the polyol composition (A) increases and the workability decreases.

In the present invention, by limiting the amount of monool in the polyether polyol (a3), it is possible to further increase the rebound resilience of the obtained foam and to impart vibration absorbing performance. Monool concentration is 25
mol% or less, more preferably 2 mol% or less.
3 mol% or less. Here, the vibration absorption performance means that the resonance transmissibility is smaller than that of the foam manufactured by the conventional technique.

In the present invention, "monool concentration" refers to ¹³ C-NMR measured using heavy acetone as a solvent.
This is a value calculated based on the spectrum. For the measurement method and spectrum assignment, see Journal of Ap
plied PolymerScience, Vol.
52, 1015 to 1022 (1994). H. Follow Carr's report.

In the above report, the amount of the allyl group was determined from the integrated value of the unsaturated bond (C = C) of the terminal allyl group, which appeared at a specific chemical shift (110 to 140 ppm) in the ¹³ C-NMR spectrum. From this value, a method of calculating the amount of unsaturated bonds present in the polyol, that is, the monool concentration is described.

The polyisocyanate composition (B) used in the present invention is obtained by using the following (b1) to (b3), and if necessary, further obtained by using (b4) It is. Incidentally, (b1) is a hydroxyl-terminated compound, and it cannot be naturally present in the polyisocyanate composition (B) as it is. That is, (b1) exists in (B) as a polyol component of the isocyanate group-terminated prepolymer.

(B1) is basically the same as (a3) described above, and a compound containing two or more active hydrogens is used as an initiator, and an alkylene oxide having three or more carbon atoms is added thereto. It is a polyether polyol having ethylene oxide added to the terminal. Examples of the “alkylene oxide having 3 or more carbon atoms” include propylene oxide, butylene oxide, and the like. In the present invention, propylene oxide is preferred. The number of functional groups of the initiator is preferably from 2 to 8, and more preferably from 2 to 6. When the number of functional groups of the initiator is less than the lower limit, the resulting flexible polyurethane foam tends to have low strength and hardness due to low crosslinking density. When it exceeds the upper limit, the viscosity of the polyisocyanate composition (B) increases, and the workability deteriorates, and the flexibility of the foam is easily lost. Examples of the initiator include those used in the above (a1), and low molecular polyols are preferable.

In (b1), the amount of EO chips is 10 to 30% by mass, preferably 11 to 28% by mass, and more preferably 12 to 26% by mass. When the amount of EO chips is less than the lower limit, the reactivity with various raw material isocyanates varies when the polyisocyanate composition (B) is obtained due to a decrease in primary hydroxyl groups (hydroxyl groups bonded to primary carbon atoms) at molecular terminals. And the polyisocyanate composition (B) is non-uniformly present, and the physical property development and the like are likely to be reduced.
If the EO chip amount exceeds the upper limit, the foam is likely to collapse.

The number average molecular weight of (b1) is from 3,000 to 1
000, preferably 3,500 to 9,500
It is. Most preferably, it is in the range of 4,000 to 9,000. When the number average molecular weight is less than the lower limit, the flexibility of the obtained foam is lost, and the elastic performance tends to be reduced. When the number average molecular weight exceeds the upper limit, the hardness of the obtained foam tends to decrease.

In the present invention, by limiting the amount of the monol in the polyether polyol (b1), it is possible to further increase the rebound resilience of the obtained foam and to impart vibration absorbing performance. Monool concentration is 25
mol% or less, more preferably 2 mol% or less.
3 mol% or less.

The preferred amount of (b1) is an amount that is 6 to 55% by mass in the polyisocyanate composition (B).
More preferably, it is 8 to 50% by mass. When the amount of (b1) is small, the low-temperature storage stability of the polyisocyanate composition (B) tends to deteriorate, and when the amount is large, the viscosity of (B) increases and the workability deteriorates.

(B2) used in the present invention has two isocyanate groups and two benzene rings, and is called a binucleate. (B3) has three or more isocyanate groups and three or more benzene rings, and is called a polynuclear compound. (B2) is supplied in the form of a single product or a mixture with (b3), and (b3) is provided as (b)
2) in the form of a mixture. Hereinafter, in the present invention, the mixture of (b2) and (b3) is referred to as polymeric MDI.

The mass ratio between (b2) and (b3) is (b2) /
(B3) = 45/55 to 95/5 is preferred, and (b2)
/ (B3) = 48/52 to 93/7 is more preferable,
(B2) / (b3) = 51/49 to 91/9 is particularly preferred. When the content of (b2) is too small, the resulting foam loses flexibility and tends to have low mechanical strength. (B
If the content of 2) is too large, the low-temperature storage stability of the polyisocyanate composition (B) decreases, and the workability tends to deteriorate.

(B2) includes 2,2'-MDI, 2,
There are three isomers of 4'-MDI, 4,4'-MDI. The isomer composition ratio of (b2) is 2,2'-MDI
And the total content of 2,4'-MDI is 10 to 50% by mass.
, And more preferably 15 to 45% by mass. 2,
When the total content of 2′-MDI and 2,4′-MDI is less than the lower limit, the low-temperature storage stability of the polyisocyanate (B) tends to decrease. If the upper limit is exceeded, the hardness of the obtained flexible polyurethane foam tends to decrease.

Used as necessary in the present invention (b4)
Is 2,4-tolylene diisocyanate (hereinafter 2,4-tolylene diisocyanate)
A mixture of TDI) and 2,6-tolylene diisocyanate (hereinafter abbreviated as 2,6-TDI) at an arbitrary ratio, preferably 2,4-TDI / 2,6-TDI = 90.
/ 10 to 70/30, more preferably 2,4-TDI /
It is a mixture of 2,6-TDI = 85/15 to 75/25 (all by mass). The TDI content of the polyisocyanate composition (B) in the present invention is preferably 20% by mass or less, more preferably 15% by mass or less in consideration of the working environment at the time of producing a flexible polyurethane foam.

If necessary, a polyisocyanate other than the above-mentioned isocyanates may be used in combination. For example,
Xylene diisocyanate, nitrodiphenyl diisocyanate, diphenyl propane diisocyanate, dimethyl diphenyl methane diisocyanate, phenylene diisocyanate, naphthylene diisocyanate, dimethoxy diphenyl diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, methyl pentane diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated TDI, hydrogenated Xylene diisocyanate, hydrogenated MDI, tetramethyl xylene diisocyanate, their polymeric form, their urethane modified form, urea modified form, allophanate modified form, biuret modified form, carbodiimide modified form, ureton imine modified form, uretdione modified form, isocyanurate modified form Sex body, and further mixtures of two or more thereof.

The polyisocyanate composition (B) used in the present invention is obtained by using the above (b1) to (b3) and, if necessary, (b4), and (b1)
Is not particularly limited, except that it is essential to use an isocyanate group-terminated prepolymer. That is, the isocyanate component in the isocyanate group-terminated prepolymer is not particularly limited. Preferred isocyanate components are (b2), Polymeric MD
I, (b4).

The urethanization reaction temperature for obtaining the isocyanate group-terminated prepolymer is preferably from 20 to 120 ° C, particularly preferably from 40 to 100 ° C. In addition, at the time of the urethanization reaction, a known urethanization catalyst such as an organic metal compound such as dibutyltin dilaurate or dioctyltin dilaurate, or an organic amine such as triethylenediamine or triethylamine or a salt thereof can be used, if necessary.

The polyisocyanate composition (B) has an isocyanate content (hereinafter abbreviated as NCO content) of 14 to 32.
% By mass, more preferably 15 to 30% by mass. The viscosity at 25 ° C. is 2,000 mPa · s
The following is preferred, and more preferably 1,900 mPa · s
It is as follows.

As the catalyst (C), various urethanization catalysts known in the art can be used. For example, triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N, N, N ', N'-tetramethylhexamethylenediamine, N, N, N', N ' ,
N "-pentamethyldiethylenetriamine, bis- (2
-Dimethylaminoethyl) ether, triethylenediamine, tertiary amine such as 1,8-diaza-bicyclo (5,4,0) undecene-7,1,2-dimethylimidazole, 1-butyl-2-methylimidazole, dimethyl Reactive amines such as ethanolamine, N-trioxyethylene-N, N-dimethylamine, N, N-dimethyl-N-hexanolamine, or their organic acid salts, stannasoctoate, dibutyltin dilaurate, naphthene Organic metal compounds such as zinc acid and the like can be mentioned. The preferable addition amount of the catalyst (C) is 0.01 to 10% by mass based on the polyol composition (A).

As the foaming agent (D), carbon dioxide gas generated by the reaction between an isocyanate group and water can be used. In addition, a small amount of a low boiling point such as cyclopentane, normal pentane, isopentane, HFC-245fa or the like can be used. An organic compound may be used in combination, or air, nitrogen gas, liquefied carbon dioxide, or the like may be mixed and dissolved in a stock solution using a gas loading device to form the mixture. The preferred blowing agent in the present invention is water. The preferred amount of the foaming agent (D) depends on the set density of the product to be obtained, but is usually 0.5 to 15% by mass based on the polyol composition (A).

As the foam stabilizer (E), organic silicon-based surfactants known in the art can be used. For example, L-520, L-540 and L-5 manufactured by Nippon Unicar.
309, L-5366, SZ-1306, Dow Corning Toray SRX-274C, SF-2962, SF
-2964, DC-5169, D made by Air Products
C-193, Shin-Etsu Chemical's F-220, F-341
And the like. The preferable addition amount of the foam stabilizer (E) is 0.1 to 10% by mass based on the polyol composition (A).

In the present invention, a cross-linking agent can be used for improving physical properties and adjusting hardness. The number average molecular weight of this crosslinking agent is from 62 to 500, preferably from 100 to 4
00. Preferred active hydrogen groups of the crosslinking agent are a hydroxyl group and an amino group.

Particularly preferred crosslinking agents include low molecular weight polyamines such as ethylenediamine, hexamethylenediamine, diethylenetriamine, tolylenediamine, diethyltolylenediamine, diaminodiphenylmethane, isophoronediamine, monoethanolamine, diethanolamine and triethanolamine. By adding alkylene oxide to low-molecular-weight amino alcohols such as monopropanolamine, dipropanolamine, tripropanolamine, N-methyl-diethanolamine, N-phenyl-dipropanolamine, and the aforementioned low-molecular weight polyamines and low-molecular weight amino alcohols And the like.

The content of the crosslinking agent is preferably 5% by mass or less, more preferably 3% by mass or less, based on the polyol composition (A). When the amount of the crosslinking agent is too small, no effect due to the use of the crosslinking agent is obtained, and when the amount is too large, the reaction control tends to be difficult.

Further, if necessary, a flame retardant, a plasticizer, an antioxidant, an ultraviolet absorber, a colorant, various fillers, an internal mold release agent, and other processing aids can be added and used.
Incidentally, among these auxiliaries, those having no active hydrogen capable of reacting with isocyanate can be used by being previously mixed with polyisocyanate.

The procedure in the method for producing a flexible polyurethane foam according to the present invention comprises a polyol composition (A), a catalyst (C), and a polyisocyanate composition (B).
A foaming agent (D), a foam stabilizer (E), a cross-linking agent, and an additive, if necessary, are previously mixed to prepare a polyol premix, and the two components of the polyol premix and the polyisocyanate composition (B) are mixed and foamed. That is the method. For mixing the two components, a low-pressure injector equipped with a known mechanical stirring device or a high-pressure injector using a high-pressure collision mixing method can be used. At this time, the isocyanate index (isocyanate group / active hydrogen group × 100) is 50 to 1
50, preferably in the range of 70-130. The mixture is then poured into a given mold to produce a flexible polyurethane foam. In this case, it is desirable that the mold is adjusted within a range of 30 to 80 ° C. in order to uniformly cure and obtain a sufficient expansion ratio. A shorter demolding time is preferable from the viewpoint of production efficiency. In the present invention, demolding can be performed in 3 to 8 minutes after the injection. You can also. The product after demolding can be used as it is, but the cell can be broken under compression or reduced pressure by a conventionally known method to stabilize the appearance and dimensions of the product.

Under good working conditions, the flexible polyurethane foam thus obtained has an apparent total density of 60
At kg / m ³ or less, the rebound resilience was 60% or more and the mechanical strength was excellent, leading to improvement of the initial problems.

The vibration transmissibility was 400 mm long and 40 mm wide.
A 50 kg iron plate is placed on a test piece having a thickness of 0 mm and a thickness of 100 mm.
This is the value when vibrating to z. Test conditions are JASO
Refer to the provisions of B407. JASO is an automobile standard established by the Automotive Engineering Society of Japan. The apparent total density, rebound resilience, compression set, tensile strength, tear strength, and elongation are values measured based on JIS K6400.

[0055]

As described above, the method for producing a flexible polyurethane foam according to the present invention realizes a safe working environment, and the obtained foam is lightweight, excellent in rebound resilience and excellent in vibration absorption. It is. The flexible polyurethane foam obtained by the present invention is used for cushioning materials for furniture such as sofas, clothing, beddings such as mattresses, mattresses, pillows, sound absorbing materials, sound insulating materials, home appliances, electronic components,
Useful for industrial sealing materials, packing materials, daily goods, etc.
In particular, it is useful for cushioning materials for automobiles and railway vehicles, and interior materials for automobiles.

[0056]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, “%” means “% by mass”.
And “ratio (ratio)” indicates “mass ratio (ratio)”.

[Blending of Polyol Composition] Synthesis Examples 1 to 10 Polyol premixes OH-1 to 10 were prepared by blending a polyol, a catalyst, water, a foam stabilizer, and a crosslinking agent in the ratios shown in Table 1.

[Synthesis of Polyisocyanate Composition] Synthesis Example 1 Capacity equipped with stirrer, cooling tube, nitrogen inlet tube, thermometer: 1
In a 00 L reactor, 20.0 kg of MDI (1), MD
36.0 kg of I (2) and 2 parts of P-MDI (1)
4.0 kg was charged and heated to 45 ° C. while stirring. Next, 10.0 kg of the polyol (19) and 10.0 kg of the polyol (20) were charged, and 80
C. for 5 hours to obtain polyisocyanate NCO-1.
I got NCO content of NCO-1 is 25.7%, 25 ° C.
Was 300 mPa · s.

Synthesis Example 2 Using the same apparatus as in Synthesis Example 1, MDI (1) was
kg, 5.0 kg of MDI (2) and 10.0 kg of TDI (1) were charged and heated to 50 ° C. with stirring.
Next, 10.0 kg of the polyol (18) and 5.0 kg of the polyol (20) were charged, and 90
The reaction was performed at a temperature of 3 ° C. for 3 hours. Thereafter, 50.0 kg of P-MDI (2) was charged to obtain polyisocyanate NCO-2. The NCO content of NCO-2 was 28.1%, and the viscosity at 25 ° C. was 250 mPa · s.

Synthesis Example 3 Using the same apparatus as in Synthesis Example 1, MDI (3) was converted to 45.0.
kg and heated to 65 ° C. while stirring. Then
23.0 kg of polyol (18) and polyol (1
23.0 kg of 9) was added, and stirred at 65 ° C. for 7 hours.
Allowed to react for hours. Thereafter, P-MDI (2) was 9.0k
g of polyisocyanate NCO-3 was obtained. NC
The NCO content of O-3 was 16.8%, and the viscosity at 25 ° C was 1,700 mPa · s.

Synthesis Example 4 In the same apparatus as in Synthesis Example 1, MDI (2) was
g, and 16.0 kg of P-MDI (3) were charged and heated to 45 ° C. while stirring. Then, the polyol (2
4) kg of 1) was charged, and stirred at 80 ° C. for 5 hours.
The reaction was carried out for an hour to obtain polyisocyanate NCO-4.
NCO-4 had an NCO content of 17.0% and a viscosity at 25 ° C of 1,900 mPa · s.

Synthesis Example 5 The same device as in Synthesis Example 1 was charged with MDI (2) at 10.0 k.
g, 20.0 kg of MDI (3) and P-MDI
(2) 15.0 kg, P-MDI (3) 15.0k
g and heated to 45 ° C. with stirring. Next, 10.0 kg of polyol (20) and polyol (21)
Was charged and reacted at 80 ° C. for 5 hours with stirring. Thereafter, 5.0 kg of TDI (2) was charged to obtain polyisocyanate NCO-5. N of NCO-5
CO content is 21.0%, viscosity at 25 ° C is 1,200m
Pa · s.

Synthetic Examples 6 to 8 Using the raw materials shown in Table 2, raw materials MDI and polymeric MDI were charged into the same apparatus as in Synthetic Example 1, and heated to 45 ° C. with stirring. Next, the raw material polyol was charged and reacted at 80 ° C. for 5 hours while stirring to obtain polyisocyanates NCO-6 to 8. N of NCO-6 to 8
It was under the control of the CO content and the viscosity at 25 ° C. NCO-6: NCO content = 27.6% Viscosity at 25 ° C. = 500 mPa NCO-7: NCO content = 11.3% Viscosity at 25 ° C. = 3,500 mPa NCO-8: NCO content = 25.8% 25 Viscosity at 400 ° C. = 400 mPa

Synthesis Example 9 The same device as in Synthesis Example 1 was used to transfer MDI (1) to 10.0 k
g, 15.0 kg of MDI (2), and P-MDI
25.0 kg of (1) was charged and heated to 45 ° C. while stirring. Next, 15.0 kg of polyol (23) was charged and reacted at 80 ° C. for 5 hours while stirring, and then 5.0 kg of TDI (1) was charged to obtain polyisocyanate NCO-9. NCO-9 had an isocyanate content of 27.4% and a viscosity at 25 ° C. of 350 mPa · s.

[0065]

[Table 1]

[0066]

[Table 2]

In Synthesis Examples 1 to 10 and Tables 1 and 2, MDI (1): content of MDI isomer = 0% MDI (2): content of MDI isomer = 30% MDI (3): MDI isomer P-MDI (1): Polymeric MDI binuclear content = 40% Isomer content in binuclear = 1% P-MDI (2): Polymeric MDI binuclear content = 35% Isomer content in binuclear = 12% P-MDI (3): Polymeric MDI Binuclear content = 50% Isomer content in binuclear = 15% * Isomer → Shows isomers other than 4,4'-MDI. (2,2'-MDI and 2,4'-MDI) TDI (1): TDI 2,4-TDI / 2,6-TDI = 80/20 TDI (2): TDI 2,4-TDI / 2, 6-TDI = 99/1 Polyol (1): polyether polyol Initiator = glycerin EO / PO = 70/30 Number average molecular weight = 3,500 Polyol (2): Polyether polyol Initiator = pentaerythritol EO / PO = 80/20 Number average molecular weight = 8,500 Polyol (3): polyether polyol Initiator = sorbitol EO / PO = 50/50 Number average molecular weight = 1,500 Polyol (4): Polyether polyol initiator = Propylene glycol EO / PO = 35/65 Number average molecular weight = 800 Polyol (5): Polyether polyol Initiator = Gly Phosphorus EO / PO = 90/10 Number average molecular weight = 12,000 Polyol (6): polyether polyol Initiator = ethylene glycol EO / PO = 100/0 Number average molecular weight = 600 Polyol (7): Polyether polyol initiator = Glycerin EO / PO = 100/0 Number average molecular weight = 1,500 Polyol (8): Polyether polyol Initiator = Sorbitol EO / PO = 100/0 Number average molecular weight = 3,800 Polyol (9): Polyether polyol Initiator = pentaerythritol EO / PO = 100/0 Number average molecular weight = 6,000 Polyol (10): polyether polyol Initiator = ethylene glycol EO / PO = 100/0 Number average molecular weight = 200 Polyol (11): Poly Ether polyol initiator = pe Nantaerythritol number average molecular weight = 8,000 Monool concentration = 35 mol% EO chip amount = 18% Polyol (12): polyether polyol Initiator = glycerin Number average molecular weight = 5,000 Monool concentration = 28 mol% EO chip amount = 15% Polyol (13): polyether polyol Initiator = glycerin Number average molecular weight = 3,000 Monool concentration = 10 mol% EO chip amount = 7% Polyol (14): Polyether polyol Initiator = glycerin Number average molecular weight = 7 2,000 monool concentration = 15 mol% EO chip amount = 20% Polyol (15): polyether polyol Initiator = sorbitol Number average molecular weight = 11,000 Monool concentration = 35 mol% EO chip amount = 33% * EO: oxyethylene Group, P O: represents an oxypropylene group. Polyol (16): polyether polyol containing polymer fine particles obtained by copolymerizing acrylonitrile and styrene Initiator = glycerin Number average molecular weight = 6,000 Monol concentration = 24 mol% Polymer fine particle content = 20% Polyol (17): acrylonitrile and Polymer fine particle-containing polyether polyol obtained by copolymerizing styrene Initiator = glycerin Number average molecular weight = 5,200 Monol concentration = 19 mol% Polymer fine particle content = 40% Polyol (18): polyether polyol Initiator = propylene glycol number Average molecular weight = 4,000 EO chip amount = 18% Polyol (19): polyether polyol Initiator = glycerin Number average molecular weight = 5,000 EO chip amount = 12% Polyol (20): polyether poly Initiator = glycerin number average molecular weight = 3,500 EO chip amount = 25% Polyol (21): polyether polyol Initiator = glycerin number average molecular weight = 7,000 monol concentration = 12 mol% EO chip amount = 22% Polyol (22): Polyether polyol Initiator = glycerin Number average molecular weight = 12,000 EO chip amount = 15% Polyol (23): Polyether polyol Initiator = Glycerin Number average molecular weight = 3,000 EO chip amount = 2% Crosslinking agent (1): Diethyl tolylenediamine molecular weight 178 Crosslinking agent (2): Triethanolamine molecular weight 105 DC-5169: Silicone foam stabilizer L-5309 made by Air Products: Silicone foam stabilizer B-4113 made by Nippon Unicar Foam stabilizer Goldschmied Ltd. TEDA L-33: amine catalyst manufactured by Tosoh Toyocat ET: amine catalyst manufactured by Tosoh Corporation

[Production and Evaluation of Flexible Polyurethane Foam] Example 1 A flexible polyurethane foam was foamed in a mold using NCO-2 and OH-1, and then taken out of the mold and immediately subjected to roller crushing. Thereafter, the molded article after crushing was left for one day and night, and various physical properties of the foam were measured according to JIS K6400. Table 3 shows the results. The 50% compression set is obtained by setting the compression atmosphere to 70 ° C. and
It was measured at 50 ° C. × 95% RH.

[Foaming conditions] Die shape: 400 mm × 400 mm × 100 mm Die material: Aluminum Die temperature: 60 ± 2 ° C. Mixing method: High pressure machine mixing Raw material temperature: 25 ± 2 ° C. Cure condition: 60 ± 2 ° C. 6 minutes Crushing conditions: 5-stage roller 80% compression

Examples 2 to 9 and Comparative Examples 1 to 5 In the same manner as in Example 1, flexible polyurethane foams were produced using the combinations shown in Table 3, and various physical properties of the foams were measured. Tables 3 and 4 show the measurement results of the foam properties. In addition, 5
For 0% compression set, the compression atmosphere is 70 ° C and 50 ° C.
× Measured at 95% RH.

[0071]

[Table 3]

[0072]

[Table 4]

As shown in Table 3, the polyisocyanate composition and the polyol composition of the present invention were treated with a catalyst,
As a result of foaming in the presence of a foaming agent and a foam stabilizer, a flexible polyurethane foam having a low apparent total density of 60 kg / m ³ or less, a high rebound resilience of 60% or more, and excellent vibration absorption performance at 6 Hz is obtained. I was able to. On the other hand, as shown in Table 4, with the combination of the polyisocyanate composition and the polyol composition other than the present invention, although the density can be reduced, problems such as a decrease in the rebound resilience and a deterioration in the vibration absorption performance are caused. Was exposed.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazunori Saeki 292-89, Kariba-cho, Hodogaya-ku, Yokohama, Kanagawa Prefecture (72) Inventor Teruo Sato 3-36-8, Ehara-cho, Nakano-ku, Tokyo (72) Inventor Takao Fukami 4-20-03 Kugenuma Coast, Fujisawa City, Kanagawa Prefecture F-term (reference) 4J034 BA01 BA03 BA07 DB03 DB04 DB05 DC50 DG02 DG03 DG04 DG05 DG10 DG12 HA01 HA07 HC12 HC63 HC71 KA01 KA02 KB05 NA01 NA03 NA05 QA05 QC01 QC02 QC08 RA03 Q05 RA03 RA09 RA11 RA12 RA15

Claims (6)

[Claims] 1. The method according to claim 1, wherein (a1), (a2), (a)
A catalyst (C) and a blowing agent (B) obtained by using the polyol composition (A) containing 3) and the polyisocyanate composition (B) obtained by using (b1), (b2), and (b3) shown below. D) A method for producing a flexible polyurethane foam, which comprises reacting in the presence of a foam stabilizer (E). Polyol composition (A): (a1): a compound having two or more active hydrogens as an initiator, and a mixture of ethylene oxide and an alkylene oxide having 3 or more carbon atoms added randomly, the number average molecular weight being 1, 000-10,000 polyether polyol (a2): a polyether polyol having a number average molecular weight of 500-5,000, to which ethylene oxide is added using a compound having two or more active hydrogens as an initiator (a3): Using a compound having two or more active hydrogens as an initiator, an alkylene oxide having 3 or more carbon atoms is added, and ethylene oxide is further added to the terminal at 10 to 30% by mass. The number average molecular weight is 3,000 to 10, , 00
0 polyether polyol polyisocyanate composition (B): (b1): using a compound having two or more active hydrogens as an initiator, adding an alkylene oxide having 3 or more carbon atoms, and further adding ethylene oxide to the terminal at 5 ~ 30% by mass
The added number average molecular weight is 1,000 to 10,000
(B2): diphenylmethane diisocyanate having two isocyanate groups and two benzene rings each (b3): polymethylene polyphenylene polyisocyanate having three or more isocyanate groups and three or more benzene rings each 2. The following (a1), (a2), (a)
A catalyst (C) comprising a polyol composition (A) containing 3) and a polyisocyanate composition (B) obtained using the following (b1), (b2), (b3), and (b4). A method for producing a flexible polyurethane foam, comprising reacting in the presence of a foaming agent (D) and a foam stabilizer (E). Polyol composition (A): (a1): a compound having two or more active hydrogens as an initiator, and a mixture of ethylene oxide and an alkylene oxide having 3 or more carbon atoms added randomly, the number average molecular weight being 1, 000-10,000 polyether polyol (a2): a polyether polyol having a number average molecular weight of 500-5,000, to which ethylene oxide is added using a compound having two or more active hydrogens as an initiator (a3): Using a compound having two or more active hydrogens as an initiator, an alkylene oxide having 3 or more carbon atoms is added, and ethylene oxide is further added to the terminal at 10 to 30% by mass. The number average molecular weight is 3,000 to 10, , 00
0 polyether polyol polyisocyanate composition (B): (b1): using a compound having two or more active hydrogens as an initiator, adding an alkylene oxide having 3 or more carbon atoms, and further adding ethylene oxide to the terminal at 5 ~ 30% by mass
The added number average molecular weight is 1,000 to 10,000
(B2): diphenylmethane diisocyanate having two isocyanate groups and two benzene rings (b3): polymethylene polyphenylene polyisocyanate having three or more isocyanate groups and three or more benzene rings (b4): tolylene diisocyanate 3. The polyol composition (A) wherein the content of (a1) is 1 to 30% by mass and the content of (a2) is 3 to 60% by mass. Or the manufacturing method of the flexible polyurethane foam of Claim 2. 4. The composition according to claim 1, wherein the polyol composition (A) contains 1 to 25% by mass of polymer fine particles.
A method for producing the flexible polyurethane foam according to claim 1. 5. The method for producing a flexible polyurethane foam according to claim 1, wherein the monool concentration in the polyether polyol (a3) is 25 mol% or less. 6. The method for producing a flexible polyurethane foam according to claim 1, wherein the monool concentration in the polyether polyol (b1) is 25 mol% or less.