JPS6390529A - Production of urethane foam - Google Patents

Abstract

PURPOSE:To obtain the titled foam in high productivity without delaying the completion of the later stage of the foaming reaction, by reaction, in the presence of a foaming agent, between polyisocyanate and polyol using, as the catalyst, a hydroxyalkyl-alkylimidazole. CONSTITUTION:The objective foam can be obtained by reaction, in the presence of a foaming agent, between a polyisocyanate and polyol using, at least as part of the catalytic system, a 1-(2-hydroxyalkyl)-2-alkylimidazole of formula I (R1 is H or methyl; R2 is 1-4C alkyl; R3 and R4 are each H, methyl, ethyl or hydroxymethyl) [pref. 1-(2-hydroxyethyl)-2-methylimidazole]. The rest of said catalytic system is pref. a polyamine of formula II (R5 and R6 are each 1-4C alkyl; R7 is alkylene, etc.) and/or a salt of amidine of formula III (R8 is H or 1-8C alkyl; R9 is 1-8C alkyl).

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing urethane foam.

[Conventional technology]

Conventionally, polyurethane foams, especially polyurethane foam molded products, have been produced using isocyanate groups (NG
A tertiary amine containing a primary amino group or a hydroxyl group that reacts with O) is used as a catalyst to suppress the movement of the catalyst in the polyurethane foam. There are techniques to prevent PVC discoloration (commonly called ``vinyl stain'') by avoiding contact with it. (Japanese Patent Application Laid-Open No. 59-191741)
[Problems to be Solved by the Invention] However, tertiary amines that have a group that reacts with NGOs tend to have reduced catalytic activity in the latter stages of the foaming reaction, which delays the completion of the reaction and prolongs demolding time, reducing production efficiency. I had the above problem.

[Means for solving problems]

The present inventors have developed a catalyst with extremely little discoloration of PVC, no decrease in catalyst activity in the latter stages of the foaming reaction, and therefore a short demolding time (which is directly correlated with the tack-free time in free cup foaming). As a result of intensive studies, we have arrived at the present invention. That is, the present invention provides a method for producing a urethane foam by reacting a polyisocyanate and a polyol in the presence of a blowing agent and a catalyst. An alkyl group of numbers 1 to 4, R3 and R4 are each hydrogen.

Methyl/L/, ethyl or hydromodimethyl group.

) 1-(2-hydroxyalkyl)-2-alkylimidazoles (a) represented by the general formula (wherein, R5+
R6 is an alkyl group having 1 to 4 carbon atoms, and %R7 is an alkylene group which may contain ether oxygen. ) or a salt thereof (b
) and/or general formula (wherein R8 is hydrogen or an alkyl group having 1 to 8 carbon atoms, R9 is an alkyl group having 1 to 8 carbon atoms, R8 and R1 are bonded to each other to form a methylated 3 to 5 alkylene groups may form one ring. n is 2 or 3). A method for manufacturing a foam (@1 invention) and a method for manufacturing a urethane foam molded product with a skin using the above manufacturing method (second invention).

In general formula (1), the alkyl group having 1 to 4 carbon atoms in R2 is methyl, ethyl, n- or iso-propylene)
Examples include straight-chain or branched alkyl groups such as v, 1-, iso- or tert-butyl.

From the viewpoint of catalytic activity, a methyl group is preferred. R3 and R
+ is hydrogen from the point of view of catalytic activity, and liquefaction (
From the viewpoint of low temperature fluidity, either or each of R3 and R4 is a methyl or ethyl group, and from the viewpoint of suppressing discoloration of PVC, a hydroxymethyl group that is reactive with NGO is preferred.

Specific examples of 1-(2-hydroxyalkyl)-2-alkylimidazoles represented by general formula (1) include 1-(2-hydroxymethy)v)-2-methylimidazolepropyl-2-methylimidazole -hydroxyethyl/l') -2-ethylimidazole.

1-(2-t x 4-1v) - 2-
meth)v-4-methylimidazo-)v, 1-(
2-hydroxymethy/L/)-2-tert, buty/v-4-hydroxymethylimidazole, 1-(2
-hydroxypropyl)-2-propy/L'-4,
5-dihydroxymethylimitasole, 1-(2-hydroquinepropyl)-2-ethyl-4-methy) L/-5
-Hydroxyalkyl tasot- tvr. i'〆1ヂ"
) j' , -fI+)I(+multi$-two cranes τ゛ball 1.

They can be easily synthesized by addition reaction of ethylene oxide or propylene oxide to compounds, and most of them are solids or viscous liquids with low melting points.

In general formula (2), the alkyl group having 1 to 4 carbon atoms which is R5 and R6 is a straight chain or branched alkyl group such as methyl, ethyl, n- or iso-10-pyl, n-, iso or tert, -butyl. However, methyl group is preferred from the viewpoint of high catalytic activity. Examples of the alkylene group R7 which may contain ether oxygen include linear or branched alkylene groups having a total of 2 to 12 carbon atoms or ether oxygen-containing alkylene groups, such as ethylene, n-propylene, tetramethylene, Straight chain polymers such as hexamethylene, 2-ethylhegysylene, decamethylene L/7? ．． Examples include a branched alkylene group and an alkylene group in which the above-mentioned ethylene or hexamethylene are linked via an ether bond. Ethylene, propylene, hexamethylene groups, or an ether oxygen-containing alkylene group in which these are bonded with an ether bond, preferably ethylene, n-propylene, or an ether oxygen-containing alkylene group in which both are bonded with an ether bond, from the viewpoint of catalytic activity;
The salt-forming acid may be either inorganic or organic, with carbonic acid and formic acid being preferred.

Examples of compounds represented by general formula (2) include dialkylaminoalkylamines (dimethylamine ethylamine, dimethylaminopropylamine, diethyl amine)
Dialkylaminoalkoxyalkylamines (dimethylaminoethoxy-10pyramine, dimethylaminoethoxy-10pyramine, etc.)
diethylaminoethoxy-10-pyramine, S/methylaminohexoxypropylamine, etc.).

Salts can be created by reacting with the corresponding acid.

Among the polyamines mentioned above, preferred compounds from the viewpoint of catalytic activity are dimenalaminopropylamine, dimethylaminoethylamine, and their carbonates, and the partial carbonates are liquid substances for low-odor lamps.

dimethy)v7 minophyllopylamine is synthesized by addition of acrylonitrile to dimethylamine, followed by reduction of the nitrile group.

The general formula of the amidine salt (c) of the catalyst in the present invention (
In 3), the alkyl group having 1 to 4 carbon atoms for R8 or R9 is methyl, air/L', n- or 1so
-propyl, n-, 1so- or tert, -butyρ groups, and when R8 and R9 are bonded to each other to form a single horn ring with an alkylene group having 3 to 5 methylenes, the raw material The number of methylenes is preferably 8 or 5-h from the viewpoint of availability and raw material cost.

In terms of catalytic activity, n is preferably 3. Examples of the compound represented by the general formula (3) include 1-methylimidacyline,
l, 2-dimethylimidacyline, 1-methy/L'-1,
4,5,6-thitrahydrobyrimidine, 1,2-dimethyl-1,4,5,6-thitrahydrobyrimidine (
4,8,0) Nonen-5 are listed. The latter two are preferred in terms of catalyst activity and low odor. Methods for synthesizing these compounds are described in Japanese Patent Publication No. 45-41226. As the salts of these amidines,
Organic acid salts described in Japanese Patent Publication No. 40558 and Japanese Patent Publication No. 45-40554 include formic acid, acetic acid, 2-ethylhexanoic acid, and oleic acid.

They are fatty acids such as nutearic acid, phenol, and carbolic acids such as cresol.

The amount of the catalyst imidazo-μ (a), polyamine (b), and amidine (C) used in the present invention is 5 to 95%, 0 to 80%, 0 to 80%, based on the total weight of these three types. ~50
%, preferably 5-80%, 5-75%, 5-4
It is 0%.

Catalyst formulation according to the invention ((a) + (b) +(
c))) can be used alone, but if necessary, it can be used in combination with other known catalysts. Other catalysts include, for example, amine-based catalysts (N,N,N-trimethylμmN'-2-hydroxyethylethylenediamine (
DABCO'T], 1.8.5-tris(3-dimethylaminopropy/L/)hexahydro-8-triazine (POLYCAT41, POLYCAT DAB
CO stands for Air Products,) & Chemicals Inc., Products, hereinafter the same), N.

N,N-)lis(8-dimethylaminopropyl/thi)amine (POLYCAT 9), N-methyl-N,N
-bis(3-dimethylaminopropyl/L/)amine (P
OLYCAT'IT), N-methyldicyclohexylamine CPOLYctane, N,N-dimethylaminoethanolamine, etc., as well as volatile N-methyl or N-ethylmorpholines, N,N,N',N'-tetramethylethylenediamine , triethylamine] and/or a metal catalyst [stannas octoate, diptylsot dilaurate, Fomure 11-not UL-22 (mercaptan tin, manufactured by Liteco, USA, etc.).

The combined ratio of the catalyst according to the present invention and the above amine catalyst is usually 1:10 to 1O:1 and preferably 1:4 to 4 on a weight basis.
:l. In addition, the ratio of combined use with metal catalyst is 1:5 to 1.
:O,OOl Preferably l:1-1:0.01.

The organic polyisocyanates and polyols used in the present invention include all those commonly used in the production of rigid, semi-rigid and flexible polyurethane foams, elastomer foams and polyurethane molded articles.

Examples of organic polyisocyanates include aromatic polyisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.), aliphatic polyisocyanates (hexamethylene diisocyanate, etc.), alicyclic polyisocyanates (isophorone diisocyanate, etc.), modified products thereof (for example, carbodiimide modification), and Examples include polypolymers containing free isocyanates produced by reaction of these with active hydrogen compounds.

Among these organic polyisocyanates, aromatic borysonanate is preferred.

Polyols include polymeric polyols such as alkylene oxides (ethylene oxide, etc.).

Propylene oxide, 1,2- and 1,4-butylene oxide, etc.) water, heavy rain alcohol/I/ (glycols such as ethylene glycol, propylene glycol; glycerin, trimethylolpropane, triethanolamine, pentaerythrin Thor, Sorpi)-/L/,
L/Polyol-/L/ having three or more OH groups such as sucrose
) and amine compounds (ethylenediamine, diethylenetriamine, tolylenediamine, xylylenediamine,
piperazine, N-aminoalkylhiberazine, N,N-
Polyether polyol/v having a structure added to dimethylaminopropylamine, cyclohexylene diamine, etc.): The polyether polyol and an ethylenically unsaturated monomer (acrylonitrile/L/, styrene, etc.).

Polymer polyol (described in U.S. Pat. No. 3,888,351) prepared by reacting methacrylate (methacrylate/L/, 7'tadiene, etc.) in the presence of a polymerization catalyst such as a radical generator; polycarboxylic acid (succinic acid, Polyether polyols obtained by reacting sebacic acid, maleic acid, adipic acid, fumaric acid, phthalic acid, dimer acid, etc.) with polyhydric alcohols; polyester polyether polyols and mixtures of two or more of these. .

Preferred among these polyols are polyether polyols and polymer polyols.

In the present invention, a crosslinking agent or a chain extender may be used if necessary, such as low molecular weight polyols (triethanolamine, jetanolamine, ethylene glycol, diethylene glycol, butanediol, trimethylolpropane, glycerin, -Bis(2-
(hydroxyethyl)phenylene ether, etc.) and polyamines (tolylene diamine, xylylene diamine, diaminodiphenylmethane, methylenebis-O-chloroaniline, etc.).

The blowing agent used in the present invention is a halogen-substituted aliphatic hydrocarbon blowing agent (fluorocarbon gas).

methylene chloride, etc.), water, etc.

Further, if necessary, surfactants (silicone foam stabilizers, etc.), colorants, fillers, miscellaneous combustible agents, stabilizers, etc. can also be used.

The amount of the diverticulant used in the present invention is usually 0.01 to 5 parts by weight, preferably 0.1 parts by weight, per 100 parts by weight of the polyol.
2 parts by weight. If it is less than 0.01 part by weight, the catalyst activity will be low and it will take too long to complete one reaction. Also 5
If the amount used is larger than part by weight, the physical properties of the resulting urethane foam, especially the compressive strength 1f (ILD), will deteriorate.

The polyurethane production method may be the same as a conventionally known method, and either a one-shot method or a full polymer method can be applied. It can also be applied to the production of elastomers or sealants, and the main raw materials, auxiliary agents, equivalent ratios, amounts added, etc. may be the same as conventional ones.

The method for producing urethane foam of the present invention is particularly useful for producing polyurethane foam molded products having a PVC skin, but it can also be used for producing other objects.

Molding by RIM method, molding by open mold, vacuum molding, etc., cold cure and hot cure, slab method, on-site construction, spray method, injection.

It can also be applied to various methods such as coating and impregnation.

The method for producing a urethane foam molded product with a PVC skin is to first set a soft polyvinyl chloride sheet inside a mold by vacuum forming, then inject the stock solution for urethane foam production into the mold and perform foam molding. or,
A polyvinyl chloride skin is formed on the inner surface of the mold by the so-called slush molding method, in which polyvinyl chloride furanutisol is heated and molded on the inner surface of the mold, and then a stock solution for producing urethane foam is injected. A method of foam molding can be used.

This can be achieved by using the catalyst of the present invention in the production of the above-mentioned urethane foam.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Examples 1 to 8 and Comparative Example 1.2 Using the following foaming recipe, foaming was carried out using the catalyst of the comparative example and the catalyst of the present invention under the following foaming conditions, and good urethane foams were obtained in both cases. Ta.

Foaming recipe: 1 Sunnics FA-708 (Note 1) 100.0 (parts by weight) Triethanolamine (industrial use) 4.0 Water
2.5 catalyst
2.0 or 2.5,
2.3 Crude MDI (Note 2) 1O5(N
(as GO index) Note 1: Manufactured by Sanyo Chemical Industries, Ltd., glycerin-propylene oxide-ethylene oxide adduct, 08 valence approximately 34 Note 2: Crude diphenylmethane diisocyanate foaming conditions raw material temperature 22.0±0.5℃ total Raw material weight
100g Stirring time 7 seconds Paper core volume used 11 Catalyst A: 1-(2-hydroxyethyl/L/)-2-methylimidazole B dimethylaminopropylamine partially hydrated carbonate [
1% pH 10.5, moisture (Karl Fischer method) 14
．． 0% by weight, total amine value 840] C: 2-ethylhexanoate of DBU C': Phenol salt of DBU Foaming operation In the two-foam formulation, raw materials other than crude MDI were accurately weighed into a 1e paper cup, and a homogeneous mixture was prepared. Then, a predetermined amount of crude MDI was added and immediately stirred at high speed for 7 seconds to obtain a urethane foam in the paper cup.

Cream thyme (CT) in this foaming process.

Rise time (RT) and tack free time (TPT) were measured.

The results are summarized in the table below.

As shown in Table 1, when only the polyamine partial carbonate of catalyst B is used, CT and RT are equal to the catalyst (A+B).
The TPT of the catalyst (A+B) was as long as 360 seconds, while the beam was equivalent to that of the CB with 20% imidazole/I/(All).
g) It was shortened to 340 seconds due to the combined effect, and it can be seen that the decrease in catalyst activity in the latter stage of the foaming reaction was suppressed.

Furthermore, when 0.5 part of DBU 2-ethylhexanoate (C), which is an amidine salt, which is the eighth component, is used in combination with the catalyst (A + B), CT does not change at all, RT shortens by only 5 seconds, and foaming occurs. Although there is almost no change in the activity in the early stage of the reaction, the TPT was shortened by a large 100 seconds to 240 seconds, and the catalyst activity did not decrease in the late stage of one reaction.

Furthermore, DBU phenol salt (C') is added to the catalyst (A+B).
Similar results were obtained when 0.3 parts of

On the other hand, containing the imidazole derivative (8) (A+B
Comparing the TPT of +C) and CB+C) that does not contain component A, there is a large difference of 240 seconds, 290 seconds, and 50 seconds, indicating that the presence or absence of the imidazole derivative (8) component has a large influence on TPT. . A similar trend was observed when 1-(2-hydroxyne "lopi)V)-2-methylimidazo-p was used as Form 20 formulation of Catalyst B.

Examples 4 to 6 and Comparative Example a (Manufacture of urethane foam molded product with PVC skin) Seikichi's print (no change in content) With the above foaming recipe, the raw material temperature was 20 + 0.5°C, 20
Use a mold of
C1 total raw material weight of 12Of was stirred in the same manner as above, poured into a mold, foamed, cured at room temperature for 10 minutes, and demolded to produce a urethane foam molded product with a PVC skin.

Contamination of mold form excluding PvC sheet is 0.2
It was 5-0.26.

This test piece was treated in an oven at 120'C for 50 hours to examine discoloration of the PVC sheet.

Coloring evaluation is shown based on the following criteria.

1: Slightly colored, 2: Orange colored, 3: Red colored,
4: Colored reddish-brown; 5: Colored black. It can be seen that the amount is much less than triethyleneduamine, which is the urethane catalyst used in Table 2.

〔Effect of the invention〕

The method for producing a urethane foam according to the present invention does not delay the completion of the late stage of the foaming reaction, thus shortening demolding time and improving production efficiency.

Furthermore, the PVC skinned urethane foam molded product of the present invention can be produced with high production efficiency, and the PVC discolors less.

Generally, when urethane foam is produced using a tertiary amine having a group that reacts with isocyanate as a catalyst, discoloration of PVC can be suppressed, but the catalyst activity in the latter stage of the reaction decreases, and the demolding time of the molded product becomes longer.

The catalyst of the present invention with a salt of 1-(2-hydroquinalkyl)imidazole, polyamine and/or amidine is a primary amino group [polyamine (b)] that reacts with an isocyanate group and a hydroxyl [imidazole]. The foaming reaction is composed of tertiary amines each having type (a)], but due to amidine salts, there is little decrease in the latter stage of the foaming reaction, especially in the presence of 1-(2-hydroxyalkyl/)-2~alkylimidazoles. Remarkable.

Furthermore, when used in urethane foam molded products using PVC for the skin, there is little discoloration of PVC, making it extremely useful in practice.

Patent Applicant Sanmapro Co., Ltd. Procedures Amendment Document February 1988 IC 7 1, Case Description 1988 Patent Application No. 237295 2, Title of Invention Process for Producing Urethane Foam 3, Person Making Amendment 4, Agent Address: 15-11 Hashino Honmachi, Higashiyama-ku, Kyoto City.
The date of the amendment order is January 7, 1985 6, the number of inventions to be increased by the amendment 7, column 8 of "Detailed explanation of the invention" of the specification subject to the amendment, and page 22 of the specification of the contents of the amendment as attached. Replace it with something.

Claims (1)

[Claims] 1. In a method for producing urethane foam by reacting polyisocyanate and polyol in the presence of a blowing agent and a catalyst, at least a part of the catalyst includes a general formula ▲ mathematical formula, chemical formula, table, etc. ▼...(1) (In the formula, R_1 is hydrogen or a methyl group, R_2 is an alkyl group having 1 to 4 carbon atoms, and R_3 and R_4 are hydrogen, methyl, ethyl or hydroxymethyl group, respectively.) 1- A method for producing a urethane foam, comprising using (2-hydroxyalkyl)-2-alkylimidazoles (a). 2. As a catalyst, there are (a) and general formula ▲ numerical formula, chemical formula, table, etc. ▼... (2) (In the formula, R_5 and R_6 are each an alkyl group having 1 to 4 carbon atoms, and R_7 contains ether oxygen. polyamines or their salts (b) and/or general formula ▲ Numerical formula, chemical formula, table, etc. ▼... (3) (In the formula, R_8 is hydrogen or carbon R_9 is an alkyl group having 1 to 8 carbon atoms, and R_8 and R_9 are bonded to each other to form one ring with an alkylene group having 3 to 5 methylenes. 2. The manufacturing method according to claim 1, which uses a salt of an amidine represented by (c) (n is 2 or 3). 3. In the method of producing a urethane foam molded product having a skin by reacting polyisocyanate and polyol in the presence of a blowing agent and a catalyst, at least a part of the catalyst includes a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ ...(1) (In the formula, R_1 is hydrogen or a methyl group, R_2 is an alkyl group having 1 to 4 carbon atoms, and R_3 and R_4 are each hydrogen, methyl, ethyl, or hydroxymethyl group.) 1- (2-hydroxyalkyl)-2-
A method for producing a urethane foam molded product with a skin, characterized by using an alkylimidazole (a). 4. As a catalyst, there are (a) and general formula ▲ numerical formula, chemical formula, table, etc. ▼... (2) (In the formula, R_5 and R_6 are each an alkyl group having 1 to 4 carbon atoms, and R_7 contains ether oxygen. polyamines or their salts (b) and/or general formula ▲ Numerical formula, chemical formula, table, etc. ▼... (3) (In the formula, R_8 is hydrogen or carbon It is an alkyl group having a number of 1 to 8, R_8 is an alkyl group having 1 to 8 carbon atoms, and R_8 and R_9 are bonded to each other to form one ring with an alkylene group having 3 to 5 methylenes. and n is 2 or 3). 5. The manufacturing method according to claim 3 or 4, wherein the skin is made of polyvinyl chloride.