JPH03200825A - Production of highly elastic polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain the title foam of a low density while reducing the amount of a fluorohydrocarbon used in a process for producing the title foam by reacting a polyol with a polyisocyanate in the presence of a catalyst, a blowing agent and a foam stabilizer, by using a specified polyisocyanate, a specified blowing agent and a specified catalyst as the respective components. CONSTITUTION:A process for producing the title foam by reacting a polyol with a polyisocyanate in the presence of a catalyst, a blowing agent and a foam stabilizer, wherein the polyisocyanate comprises diphenylmethane diisocyanate and/or its derivative; the blowing agent comprises at least 2 pts.wt., based on 100 pts.wt. polyol (e.g. polyetherpolyol) or at most 20 pts.wt., based thereon, halogenate hydrocarbon (e.g. CFC-11); and the catalyst comprises at least one member selected from among compounds of formulas I-IV [wherein R<1> is 1-3C alkyl or dimenthylamino(2-3C)alkyl; R<2> and R<3> are each H or 1-3C alkyl; (l), (m) and (n) are each 2 or 3; R<7> is 1-4C alkyl; R<4> is H, R<7>, allyl, benzyl or phenyl; R<5> and R<6> are each H or R<7>; R<9> is CH2CH(X)OH (wherein X is H or R<7>); R<8> and R<10> are each R<7> or R<9>, either of them is R<7>; and (p) is 2-6].

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to the use of polyols and polyisocyanates as catalysts,
This invention relates to a method for producing highly elastic polyurethane foam by reacting it in the presence of a blowing agent and a foam stabilizer.

More specifically, the present invention relates to a method for producing a highly elastic flexible polyurethane foam using a polyether polyol or a mixture of a polyether polyol and a polymer polyol, and diphenylmethane diisocyanate and/or its derivatives.

[Prior Art] Highly elastic polyurethane foam is widely used in many products such as automobile seat cushions, vehicles, furniture, and bedding.

Conventionally, toluene diisocyanate (hereinafter abbreviated as TDI) or a mixture of TDI and diphenylmethane diisocyanate (hereinafter abbreviated as MDI) has been used as an isocyanate raw material in the production of high modulus polyurethane foam.

However, TDI has a problem of deteriorating the working environment due to its high vapor pressure, high toxicity, and strong odor. Furthermore, since TDI has low reactivity with the raw material polyol, there have been problems such as low productivity and increased equipment costs.

In order to improve the above-mentioned problems faced by TDI, M
A method for producing high elastic polyurethane foam using DI and/or its derivatives is disclosed in JP-A-53-5129.
No. 9, JP-A-57-109820, JP-A-62-11
It is proposed in No. 2616. Foams manufactured based on MDI and/or its derivatives are generally referred to as all-MDI high modulus polyurethane foams, which provide excellent foam physical properties and low toxicity, making them ideal for a good working environment on production lines. It has excellent features such as easy maintenance, fast production speed, and high productivity.

The all-MDI high modulus polyurethane formulation has a fatal drawback in that the fluidity of the system liquid and the fluidity of the foam are extremely poor, making it difficult to reduce the density of the foam. Therefore, as a blowing agent, a halogenated hydrocarbon such as trichloromonofluoromethane (hereinafter abbreviated as CFC-11) is used in an amount of 5 to 15 parts by weight based on the polyol.
The foam density is reduced by ensuring liquid flowability and bubble fluidity. However, even in the current situation, all M
It is desired to develop manufacturing techniques to improve DI high modulus polyurethane formulations to lower densities.

In addition, among halogenated hydrocarbons, efforts have been made in recent years to reduce and further regulate the use of fluorocarbon compounds such as CFC-11, which has the risk of destroying the ozone layer. Reduce the amount of fluorocarbon compounds used as blowing agents in the production of polyurethane foam,
Instead, using more water is an urgent and important issue today. On the other hand, there are so-called substitute fluorocarbon compounds for fluorocarbon compounds such as CFC-11, which may cause ozone layer depletion, such as methylene chloride, dichlorotrifluoroethane, and dichloromonofluoroethane (hereinafter abbreviated as HCFC-123 and HCFC-141b, respectively). ) have been proposed. However, these alternative fluorocarbon compounds still have the potential to deplete the ozone layer, and are more expensive than conventionally used fluorocarbon compounds, so they cannot be used at the same level for economic reasons. It is difficult to use in Therefore, there is a strong desire to develop a formulation that reduces the amount of fluorocarbon compounds used and instead uses a large amount of water as a blowing agent.

However, the use of large amounts of water as a blowing agent poses several technical problems. That is, in the process of forming the foam, the stability of the foam is significantly deteriorated, phenomena such as foam collapse occur, the process range is narrow, the physical properties of the foam are also deteriorated, and it becomes extremely difficult to reduce the density of the foam. Furthermore, deterioration of the formability of the foam, such as cell roughness and voids, is unavoidable.

Until now, the catalyst for all-MDI high modulus polyurethane foam is, for example, triethylenediamine as a base catalyst and bis(2-dimethylaminoethyl) as a co-catalyst.
Amine catalysts such as ethers and dimethylethanolamine have been used.

However, with these amine catalyst systems, it is not possible to lower the density of the current foam using a fluorocarbon compound as a blowing agent, and in a system in which the amount of fluorocarbon compound as a blowing agent is reduced and the amount of water is increased, It has been difficult to obtain practical high modulus polyurethane foams with low density.

[Problems to be Solved by the Invention] The present invention solves the following problems in the production of high elastic polyurethane foam:
To provide a manufacturing method that can achieve foam stabilization and low density, which have been problems in the past, and an industrially useful method for manufacturing highly elastic polyurethane foam that can reduce the use of fluorocarbon compounds as blowing agents. It is something.

[Means for Solving the Problems] As a result of intensive studies on high modulus polyurethane foam systems from the perspective of catalysts, the present inventors found that by using an amine compound having a specific chemical structure as a catalyst, it is possible to improve We discovered a new fact that it is possible to achieve a lower density foam, and that by reducing the amount of fluorocarbon compounds and increasing the water content, we can improve the stability and bottom shape of the foam during foaming and produce a foam with a lower density. , we have completed the present invention.

That is, the present invention provides a method for producing a highly elastic polyurethane foam by reacting a polyol and a polyisocyanate in the presence of a catalyst, a blowing agent, and a foam stabilizer.
The present invention relates to a method for producing a highly elastic polyurethane foam, characterized in that one or more selected from the active hydrogen-containing amine compounds represented by ), (II), (m), or (IV) are used as a catalyst.

Or R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Moreover, g represents an integer of 2 or 3. ) (general formula (
n), m and n represent an integer of 2 or 3. ) (In general formula (m), R4 represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an allyl group, a benzyl group, or a phenyl group, and R
5 and R6 represent hydrogen or an alkyl group having 1 to 4 carbon atoms. ) (In the general formula (1), R1 represents an alkyl group having 1 to 3 carbon atoms or a dimethylaminoalkyl group in which the alkyl group has 2 or 3 carbon atoms, and R2 and /(in the general formula (IV), R7 is an alkyl group having 1 to 4 carbon atoms, R9 is -CH2C
H(X)OH (where X represents hydrogen or an alkyl group having 1 to 4 carbon atoms), and R8RIO represents an alkyl group having 1 to 4 carbon atoms or -CH2CH(X)OH (where X represents hydrogen or represents an alkyl group having 1 to 4 carbon atoms, at least one of R8 or R" represents an alkyl group, and p represents an integer of 2 to 6.) [Function] The details of the present invention are as follows. Explain.

The catalyst of the present invention includes the general formulas (I), (II),
An amine compound having active hydrogen represented by (III) or (IV) can be used.

As the amine compound of general formula (I), N-methylpiverazine, N-(2-dimethylaminoethyl)piperazine, N-methyl-3-methylpiverazine, N-methylhomopiperazine is used as the amine compound of general formula (n). teeth,
N,N-dimethyl(3-dimethylaminopropyl)ethylenediamine, bis(N,N-dimethylaminoethyl)
The amine compounds of amine, bis(N,N-dimethylaminopropyl)amine, and Mongan 1) include imidazole,
2-methylimidazole, 4-methylimidazole, 2
-Ethyl-4-methylimidazole, 2-isopropylimidazole, 2-ethylimidazole, 2-phenylimidazole, the amine compound of general formula (IV) includes N,N-diisopropanol-N'N'-dimethylpropanediamine, Examples include N,N'-diisopropanol-N,N'-dimethylpropanediamine, N,N-diethanol-N', N'-dimethylethylenediamine, and N,N'-diethanol-N,N'-dimethylethylenediamine. . Among these, particularly preferred compounds include N-methylpiverazine, N-methylhomopiperazine, N,N-dimethyl(3-dimethylaminopropyl)ethylenediamine, bis(N,N-dimethylaminopropyl)amine, 2-methylimidazole and -Methylimidazole, N,N-diisopropanol-N.

N'-dimethylpropanediamine, N,N-die9)-
RuN'N'-dimethylethylenediamine, N,
N'-diethanol-N,N'-dimethylethylenediamine is mentioned. Further, the amine catalyst of the present invention can be used in combination with another compound having a tertiary amino group as a cocatalyst. Examples of other tertiary amino group-containing compounds include triethylamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylene Diamine, N, N, N'N'
N'pentamethyldiethylenetriamine, N, N, N'
.

N',N'-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N'N''N''-pentamethyldipropylenetriamine, N,N.

N', N'-tetramethylguanidine, 1,3°5-
Tris(N,N-dimethylaminopropyl)hexahydro-8-triazine, 1,8-diazabicyclo[5,4
,0] undecene-7, triethylenediamine, N,
N, N', N'N'-pentamethyldiethylenetriamine, N, N, N'N'-tetramethylhexamethylenediamine, N-methyl-N'-(2-dimethylamino)ethylpiperazine, N, N'- Dimethylpiperazine, N-methylmorpholine, N-ethylmorpholine N
.

N-dimethylethanolamine, dimethylaminoethoxyethanol, N,N,N'-trimethylaminoethylethanolamine, 1,3-bis(N,N-dimethylamino)-2-propertool, bis(2-dimethylaminoethyl ) ether etc., preferably triethylenediamine and/or bis(2-dimethylaminoethyl)ether.

Furthermore, the organic carboxylate salt of the amine compound of the present invention, the organic carboxylate salt of other tertiary amines, and the organic tin compound can be appropriately used as co-catalysts as long as the catalytic function of the present invention is not lost.

The catalyst of the present invention may be prepared by mixing the amine compound of the present invention alone or with other amine catalysts as described above. When adjusting the mixture, dipropylene glycol, ethylene glycol, 1,4-butanediol, water, etc. can be used as a solvent if necessary, but the amount of the solvent is
Although not particularly limited, it is preferably about 70% or less of the total amount of the catalyst. The catalyst produced in this way is
It can be used by adding it to polyol. Also, various amine catalysts may be added separately to the polyol.

The amount of the amine catalyst used in the present invention is usually 0.02 to 10 parts by weight based on 100 parts by weight of the polyol.

The polyol used in the present invention is a known polyether polyol, polyester polyol and/or polymer polyol, more preferably a polyether polyol or a mixture of a polyether polyol and a polymer polyol. As the polyether polyol, for example, polyurethane can be obtained by addition reaction of ethylene oxide or propylene oxide to a polyhydric alcohol such as ethylene glycol, glycerin, trimethylolpropane, or pentaerythritol.
It can be produced by the method described in Handbook (written by Gunter Qertel), pages 42 to 53 and in JP-A-62-112616. Examples of the polymer polyol include, for example, Polyurethane Handb, which is obtained by reacting the polyether polyol with an ethylenically unsaturated monomer such as butadiene, acrylonitrile, styrene, etc. in the presence of a radical polymerization catalyst.
ook (Gun te r Oer te
1), pages 75 to 76.

The polyisocyanate used in the present invention contains at least MDI and/or a derivative thereof, and the content thereof is 50%.
In the above case, the catalytic effect of the present invention is significantly exhibited. M
Examples of DI and its derivatives include mixtures of MDI and its polymer polyphenyl-polymethylene diisocyanate, and/or diphenylmethane diisocyanate derivatives having terminal isocyanate groups. Examples of the former mixture include a mixture of MDI and its derivative polyphenyl-polymethylene polyisocyanate, which is described in JP-A-53-51299. Examples of the latter diphenylmethane diisocyanate derivatives having a terminal isocyanate group include:
JP-A-57-109820, JP-A-62-11261
It is obtained by reacting MDI, polyphenyl-polymethylene polyisocyanate and/or a mixture thereof described in No. 6 with a polyether diol or triol at room temperature or elevated temperature, optionally in the presence of a catalyst. Examples include known terminal isocyanate prepolymers.

The isocyanate index of the present invention is not particularly limited, but generally ranges from 70 to 120.

As the halogenated hydrocarbon used as a blowing agent in the present invention, known halogenated methane and halogenated ethane can be used. Among these, CFC-11, HCFC-12
Preferred are halogenated carbons or halogenated hydrocarbons such as No. 3 and HCFC-141b. The number of parts used is 20 parts by weight or less, preferably 0 to 15 parts by weight, per 100 parts by weight of the polyol. The number of parts as a blowing agent is 2 parts by weight or more, preferably 2 parts by weight per 100 parts by weight of polyol.
．． 5 to 5 parts by weight, but when using water alone,
3 parts by weight or more is preferred. The amounts of water and chlorofluorocarbon used can be appropriately selected depending on the desired foam density.

In the present invention, a crosslinking agent or a chain extender can be added if necessary. Examples of crosslinking agents or chain extenders include low molecular weight polyhydric alcohols such as ethylene glycol, 1,4-butanediol, glycerin, etc., low molecular weight amine polyols such as jetanolamine,
Triethanolamine, etc., polyamines, e.g., ethylene diamine, xylylene diamine, methylene bis-orthochloroaniline, etc., secondary diamines, e.g., aliphatic and cycloaliphatic secondary diamines, polyoxybuvopylene secondary diamines, aromatic Examples include group secondary diamines.

If necessary, organic silicon compounds, colorants, flame retardants, anti-aging agents and other known additives can also be used as surfactants. The types and amounts of these additives can be used within the commonly used ranges as long as they do not deviate from known formats and procedures.

[Effects of the Invention] According to the present invention, it has become possible to reduce the density of high-elastic polyurethane foam using a fluorocarbon compound as a blowing agent, which has been difficult until now. Furthermore, in a formulation that reduces the amount of fluorocarbon compounds and increases the amount of water, it has become possible to improve foam stability and moldability during foaming, and to achieve lower density.

[Examples] The present invention will be described below based on Examples and Comparative Examples, but the present invention is not limited to these Examples.

The following formulation was used for the stem. The amount of water and halogenated hydrocarbon as a blowing agent and the type of catalyst were varied, and the stability of the foam during foam foaming, moldability and physical properties of the foam were measured using the following methods under specified foaming conditions. . The results are shown in Tables-1 and -2.

a, Formulation Examples 1 to 16 and Comparative Examples 1 to 6 All MDI High Elasticity Polyurethane Foam 1) Polyether polyol, OH value -28 mg K OH/g (Tetra 2) 3) Mixture of ol and triol , average molecular weight 7000,
Ethylene oxide content: 15%) Silicone surfactant (manufactured by Toray Silicone, 5RX-274C) Catalyst abbreviations in the table: NMP, N-methylpiverazine NMHP, N-methylhomopiperazine DMNAEP, N-(2-dimethylaminoethyl)piperazine BDMAPA, bis(N,N-dimethyl-3-aminopropyl) amine 2MIZ; 33% 2-methylimidazole-dipropylene glycol solution DIPDPA, N,N-diisopropanol-N'
N'-dimethylpropanediamine 4) DEDEA, N,N-diethanol-N.

N'-dimethylethylenediamine TEDA-L33; 3B% triethylenediamine-dipropylene glycol solution (manufactured by Tosoh Corporation) TOYOCAT-NP; 4-methyl-1(2-dimethylaminoethyl) piperazine (manufactured by Tosoh Corporation) PMDPTA, N , N, N', N', N.

N'-Pentamethyldibropyrenetriamineisocy71-) NC0a degree -25.0%, mixture of diphenylmethane diisocyanate and its derivatives Foaming conditions Raw material liquid temperature 20±1°C Stirring speed 6000 rpm (5 seconds) Mold Aluminum box ( Dimensions, 25 x 25 x 25 cm), foaming mold temperature 40°C, and all Jll rotation settings were measured.

・Reactive cream time: Foaming start time (seconds) Gel time: Resin (stringing) time (seconds) Rise time: Time to reach maximum foaming height (seconds) ・Foam stability evaluation rise time Evaluation was made based on the size of the subsequent form depression.

・Foam expansion ratio The value obtained by dividing the foam's maximum foaming height by the foam weight (c
m/g) The larger this value, the greater the foaming effect of water and the lower the density of the foam.

・Foam density A test piece measuring 20 x 20 x 10 cm was taken from the center of the foam and its density was measured.

・Evaluation of moldability The state of cell roughness and voids in the foam was observed and ranked in five stages.

1: Almost none 2: Small 3: Medium 4: Large 5: Very large As is clear from Tables 1 and 2, in a formulation in which the amount of CFC as a blowing agent is reduced and the amount of water is increased, a compound having active hydrogen is used as a catalyst. By using it as a molded foam, it was possible to stabilize the foam and produce a molded foam with low density and excellent moldability.

On the other hand, as seen in Comparative Examples 1 to 6, with the existing catalysts, foams with high density and moldability with large cell roughness were obtained. For this reason, with these catalysts, it is difficult to reduce fluorocarbons by increasing the amount of water used.

Procedural amendment Heisei Year July 17th

Claims (1)

[Claims] (1) In a method for producing polyurethane foam by reacting a polyol and a polyisocyanate in the presence of a catalyst, a blowing agent, and a foam stabilizer, as the polyisocyanate,
a mixture with at least diphenylmethane diisocyanate and/or its derivatives, the blowing agent is water or water and a halogenated hydrocarbon, and the amount of the polyol is 10
0 parts by weight, 2 parts by weight or more of water and 20 parts by weight or less of halogenated hydrocarbon, and at least the following general formula (I)
, (II), (III) or (IV) as a catalyst. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the general formula (I), R^1 is an alkyl group with 1 to 3 carbon atoms, or an alkyl group with 2 or 3 carbon atoms. Represents a certain dimethylaminoalkyl group, R^2 and/or R^3 are
Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Also,
l represents an integer of 2 or 3. ) General formula (II) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ (In general formula (II), m and n represent integers of 2 or 3.) General formula (III) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼(III) (In general formula (III), R^4 represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an allyl group, a benzyl group, or a phenyl group, and R^5 and R^6 represent hydrogen or carbon Represents an alkyl group with numbers 1 to 4.) General formula (IV) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (IV) (In general formula (IV), R^7 is an alkyl group having 1 to 4 carbon atoms, R^9 represents -CH_2CH(X)OH (here, X represents hydrogen or an alkyl group having 1 to 4 carbon atoms), and R^8
, R^1^0 is an alkyl group having 1 to 4 carbon atoms or -CH
_2CH(X)OH (where X is hydrogen or has 1 to 4 carbon atoms)
represents an alkyl group), at least one of R^8 or R^1^0 represents an alkyl group, and p represents an integer of 2 to 6. )(2) The polyisocyanate is
It is a mixture with diphenylmethane diisocyanate and/or its derivatives, and has an isocyanate index of 7.
0 to 120, the manufacturing method according to claim (1). (3) The production method according to claim (1) or (2), wherein the polyol is a polyether polyol or a mixture of a polyether polyol and a polymer polyol. (4) The halogenated hydrocarbons are trichloromonofluoromethane (CFC-11), dichlorotrifluoroethane (HCFC-123), and dichloromonofluoroethane (HCFC-141b), Claim No. 1
) to (3). (5) The blowing agent is water and the amount of the polyol is 100%
The manufacturing method according to any one of claims (1) to (3), wherein the amount of water is 3.0 parts by weight or more based on parts by weight. (6) Claim (1) characterized in that the compound of general formula (I) is N-methylpiverazine, N-methylhomopiperazine, and N-(2-dimethylaminoethyl)piperazine. manufacturing method. (7) The compound of general formula (II) is N,N-dimethyl-(
3-dimethylaminopropyl)ethylenediamine and bis(N,N-dimethylaminopropyl)amine. (8) The manufacturing method according to claim (1), wherein the compound of general formula (III) is 2-methylimidazole and 4-methylimidazole. (9) The compound of general formula (IV) is N,N-diisopropanol-N',N'-dimethylpropanediamine, N,
N'-diisopropanol-N,N'-dimethylpropanediamine, N,N-diethanol-N', N'-dimethylethylenediamine, N,N'-diethanol-N,
The manufacturing method according to claim (1), characterized in that N'-dimethylethylenediamine is used.