JPH07207051A - Production of semirigid urethane foam - Google Patents

Abstract

PURPOSE:To produce a semirigid urethane foam which is non-crashing and is improved in touch and moldability by reacting a specified isocyanate component with a polyol and a water- -containing resin component. CONSTITUTION:An aromatic polyisocyanate (A) is reacted with a polyol (B) of a molecular weight of 700-12000 and a mono-ol (C) of a molecular weight of 35-1000 in such amounts to give a C/A equivalent ratio of 0.01-0.2 and a B/A equivalent ratio of 0.01-0.2 to obtain an isocyanate component. This component is reacted with a polyol, a resin component containing water and other adjuvants and an amine catalyst for expansion to obtain a semirigid urethane foam of a density of 0.03-0.08g/cm<3>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing semi-rigid urethane foam such as headrests, armrests, center consoles and rear consoles used as interior materials for automobiles, especially non-crash in soft polyvinyl chloride skin integral molding. Ing semi-rigid urethane foam manufacturing method.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture semi-rigid urethane foam, an integral molding method in which a soft polyvinyl chloride skin is attached to a mold, a semi-rigid urethane undiluted solution is injected, and foam-cured is used. . In recent years, urethane foams used especially for automobile interior materials are required to have a low density due to economical factors. However, when the amount of water used as a foaming agent is increased to lower the density, a closed cell is likely to be formed. Especially, in the case of the integral molding method with a soft polyvinyl chloride skin and a core material, a crash after molding is performed. Since this is impossible, there is a problem such as shrinkage after molding. In recent years, due to the toxic problem of tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) has come to be used. In the case of MDI, although it has excellent reactivity, it has a closed cell structure. There was a drawback that it was easy to become.
Conventionally, as a method of physically opening a closed cell,
A method of crushing a foam between rolls is generally used, but it was impossible to apply it to an integral molding method including a core material such as a headrest. As a cell opener, a polymer polyol prepared by polymerizing acrylic or styrene in a polyether polyol has been generally used, but it has a large settling property but is insufficient in low density although it is effective. was there. When a polymer polyol is used, there is a problem that the viscosity becomes high, air is entrained during mixing, which causes voids, and the feel of the foam becomes poor. For the above reasons, M
It has been desired to develop a method for producing a semi-rigid urethane foam having a low density and requiring no crushing after molding (non-crushing) by using an isocyanate component containing DI as a main component.

[0003]

The problem to be solved by the present invention is to use an isocyanate component containing MDI as a main component, which has a low density and does not require crushing after molding (non-crashing). It is to provide a method for manufacturing a semi-rigid urethane foam and an integral molding method with a skin (usually made of soft vinyl chloride).

[0004]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a method for producing a semi-rigid urethane foam having a low density and capable of non-crushing after demolding. It was found that the use of the isocyanate component reacted with the polyisocyanate makes it possible to obtain a semi-rigid urethane foam having a non-crushing feel and excellent moldability, and has completed the present invention.

That is, the present invention is as follows. (1) In a semi-rigid foam obtained by reacting an isocyanate component with a resin component containing a polyol, water and other auxiliaries, the isocyanate component is an aromatic polyisocyanate (A) and a molecular weight of 700 to 12000. Which is a reaction product of the polyol (B) and the monool (C) having a molecular weight of 35 to 1000, wherein the equivalent ratio (C / A) of the monool (C) and the aromatic polyisocyanate (A) is 0. 01-0.2, and the equivalent ratio (B / A) of the polyol (B) and the aromatic polyisocyanate (A) is 0.01.
The method for producing a semi-rigid urethane foam is characterized in that it is ˜0.2. (2) The method for producing a semi-rigid urethane foam according to (1), wherein the aromatic polyisocyanate (A) is a polyisocyanate containing diphenylmethane diisocyanate as a main component. (3) The method for producing a semi-rigid urethane foam according to (1), wherein the monool (C) is an adduct of alcohol and alkylene oxide. (4) The method for producing a semi-rigid urethane foam according to (1), wherein the molding method is an integral molding method of urethane and a soft polyvinyl chloride skin.

The polyol which can be used as the resin component of the present invention is at least water, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, triethanolamine, ethylenediamine, tolylenediamine, diaminodiphenylmethane and the like. A polyether polyol in which two or more active hydrogen compounds are used as starting materials and alkylene oxides represented by propylene oxide, ethylene oxide, butylene oxide, etc. are used alone or in combination. Polymer polyol obtained by graft-polymerizing acrylic or styrene in these polyether polyols, or a mixture of polyether polyol and polymer polyol, and one or more dibasic acids such as adipic acid and sebacic acid, and ethylene glycol- Terminal obtained by reacting one or more polyhydric alcohols such as propylene, propylene glycol, diethylene glycol, triethylene glycol, glycerin, and trimethylolpropane in a stoichiometric excess. Also included are polyester polyols having a hydroxyl group, polycaprolactone polyols obtained by ring-opening polymerization of caprolactone, and the like. These polyols preferably have a molecular weight of 500 to 12000, particularly preferably 1000 to 5000 for a polyether polyol having 2 hydroxyl groups and 3000 to 8000 for a polyether polyol having 3 hydroxyl groups. When a graft polyol is used, the amount used is preferably 30% by weight or less based on the total amount of all active hydrogen-containing compounds. If the graft polyol exceeds 30% by weight, the polyurethane becomes too hard, which is not preferable, and the viscosity of the resin becomes too high.

The isocyanate component which can be used in the present invention is obtained by reacting a high molecular weight polyol and a small amount of monool with an excess of aromatic polyisocyanate. Examples of the aromatic polyisocyanate (A) include phenylene diisocyanate, tolylene diisocyanate (TDI), 4,4′-, 2,4′-methylenebis (phenyl isocyanate) and various isomer mixtures (MDI). ), Uretonimine-modified liquid MD
Examples thereof include I (liquid MDI), polymethylene polyphenylene polyisocyanate (crude MDI), and the like, or a mixture of two or more thereof. Especially polyisocyanates containing MDI as a main component, such as crude MDI and liquid MDI
One or a mixture of two or more thereof is preferable.

As the polyol (B) having a molecular weight of 700 to 12000, the same polyol as the resin component can be used. These polyols have a molecular weight of 500-1
It is preferably 2000, and particularly preferably 1000 to 5000 for the polyether polyol having two hydroxyl groups and 3000 to 8000 for the polyether polyol having 3 hydroxyl groups.

Monool (C) having a molecular weight of 100 to 2000 is represented by propylene oxide, ethylene oxide, butylene oxide, etc., starting from one active hydrogen compound such as methanol, ethanol, isopropanol and stearyl alcohol. Are polyether polyols and mixtures of these alkylene oxides, alone or in combination. Preferred are monools having a molecular weight of 300 to 1000 obtained by adding ethylene oxide to methanol. When the molecular weight is 100 or less, the foam becomes hard, and when the molecular weight is 2000 or more, the foam breaking effect of the foam is lost.

In producing the isocyanate component of the present invention, the ratio of the aromatic polyisocyanate (A), the polyol (B) and the monool (C) is such that the monool (C) and the aromatic polyisocyanate ( Equivalent ratio of (A) (C
/ A) is 0.01 to 0.2, and the equivalent ratio (B / A) of the polyol (B) and the aromatic polyisocyanate (A) is in the range of 0.01 to 0.2. The equivalent ratio of each is in the range of 0.02 to 0.1. When the equivalent ratio of the monool (C) to the aromatic polyisocyanate (A) is 0.01 or less, there is no effect of preventing the shrinkage of the foam, and when it is 0.2 or more, the curing property deteriorates. The equivalent ratio of the polyol and the aromatic polyisocyanate (A) is 0.0
When it is 1 or less, the foam becomes too hard and the feel becomes poor.
When it is 0.2 or more, the viscosity of the product is too high and it is difficult to mold. The order in which the polyol and the monool are added to the aromatic polyisocyanate may be simultaneous, or they may be separately synthesized and then mixed. Moreover, you may mix a part of aromatic polyisocyanate later.

Examples of the cross-linking agent are triethanolamine, diethanolamine, a compound obtained by adding 2 to 3 moles of propylene oxide and ethylene oxide to 1 mole of aniline, propylene oxide to 1 mole of ethylenediamine,
The compound which added 4-5 mol of alkylene oxides, such as ethylene oxide, is mentioned.

Water reacts with aromatic isocyanates,
Besides forming a polyurea component, its main purpose is to generate carbon dioxide gas and act as a foaming agent, which is an essential component. The amount used is 1 to 10 parts by weight with respect to 100 parts by weight of the polyol component. A blowing agent other than water can be used in combination.

Amine catalysts for foaming include, for example, triethylamine, tripropylamine, triisopnopalamine,
Tributylamine, trioctylamine, hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine, monoethanolamine, diethanolamine, triethanolamine, trimethylaminoethylethanolamine, N-methyldiethanolamine, N , N-dimethylethanolamine, diethylenetriamine, N, N, N ', N'-
Tetramethylethylenediamine, N, N, N ', N'-
Tetramethyl propylene diamine, N, N, N ', N'
-Tetramethylbutanediamine, N, N, N ', N'-
Tetramethyl-1,3-butanediamine, N, N,
N ', N'-tetramethylhexamethylenediamine, bis- [2- (N, N-dimethylamino) ethyl] ether, N, N-dimethylbenzylamine, N, N-dimethylcyclohexylamine, N, N, N ', N'N "-pentamethyldiethylenetriamine, formate salts and other salts of triethylenediamine, oxylalkylene adducts of amino groups of primary and secondary amines, aza ring compounds such as N, N-dialkylpiperazines, JP-A-52-04
3517 β-aminocarbonyl catalyst, JP-A-53-0
14279 β-aminonitrile catalyst and the like. These catalysts are used alone or as a mixture, and the amount used is 0.1 to 10 parts by weight with respect to 100 parts by weight of the compound having active hydrogen.

The foam stabilizer is a conventionally known organosilicon activator, for example, L-520 and L manufactured by Nippon Unicar Co., Ltd.
-532, L-540, L-544, L-550, L-
3350, L-5305, L-3600, L-360
1, L-5305, L-5307, L-5309, L-
5710, L-5720, L-5740M, L-620
2 and the like, and SH-19 manufactured by Torre Silicon Co., Ltd.
0, SH-192, SH-194, SH-200, SR
X-253, SRX-274C, SF-2961, SF
-2962, SRX-280A, SRX-294A and the like, manufactured by Shin-Etsu Silicone Co., Ltd. F-114 and F-1.
21, F-122, F-220, F-230, F-25
8, F-260B, F-317, F-318, F-34
1, F-601, F-606, X-20-200, X-
20-201 and the like, and TFA-4200, TFA-4202 and the like manufactured by Toshiba Silicone Co., Ltd.
The amount of these foam stabilizers used depends on the amount of the compound 10 having active hydrogen.
It is 0.1 to 10 parts by weight with respect to 0 parts by weight.

Examples of the flame retardant include tris (2-chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris (dibromopropyl) phosphate, CR-505 and CR-507 manufactured by Daihachi Chemical Co., Ltd., Fyrol manufactured by Akzo Japan. -6 or the like is used. In addition, a plasticizer, a stabilizer, a coloring agent and the like can be added if necessary.

The isocyanate index [NCO / active hydrogen-containing group equivalent ratio × 100] during the production of polyurethane is 60.
~ 140, preferably 70-120, particularly preferably 8
0 to 110. The manufacturing equipment normally used for manufacture of polyurethane can be utilized. Various foams can be manufactured in closed or open molds. Polyurethane is usually produced by mixing and reacting raw materials using a low-pressure or high-pressure mechanical device. The manufacture of the present invention is useful in the manufacture of molded foam. It is also possible to use RIM (reaction injection molding). The polyurethane obtained may be either flexible or semi-rigid foam, but semi-rigid foam is preferred. The density of the resulting polyurethane is 0.
It is preferably in the range of 03 to 0.08 g / cm ³ . When the density is less than 0.03 g / cm ³ , moldability is deteriorated, which is not preferable, and when the density exceeds 0.08 g / cm ³ , it is economically unfavorable. The semi-rigid urethane foam obtained by the present invention is mainly used for automobile interior parts such as crash pads, armrests and headrests.

[0017]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. The numbers in the examples represent parts by weight, unless otherwise specified.

The raw materials used in the examples and comparative examples are as follows. (1) Polymer polyol A polymer polyol obtained by graft-polymerizing acrylonitrile and styrene in a polyether polyol, POP36-20 (OH value 20) manufactured by Mitsui Toatsu Chemicals, Inc. (2) Polyol I A polyol having an OH value of 24, which is obtained by adding PO to glycerin and finally adding 15% by weight of EO. (3) Polyol II A polyol having an OH value of 55 in which PO is added to glycerin. (4) Foam stabilizer SRX-274C manufactured by Toray Silicone Co., Ltd. (5) Catalyst Caurizer No. 1; tetramethylhexamethylenediamine DABCO 33LV; triethylenediamine 33% DP
G solution (6) Monool A Ethanol oxide added to methanol OH number 10
Uniol 550 manufactured by NOF CORPORATION with 2 monools. (7) Monool B OH number 56 obtained by adding ethylene oxide to methanol
This is a monol made by Nippon Oil & Fats Co., Ltd. Uniol 100
0. (8) 50 parts by weight (0.400 equivalents) of isocyanate A 4,4′-MDI and 50 parts by weight (0.369 equivalents) of polymeric MDI and 20 parts by weight of polyol II (0.0086 equivalents) at 80 ° C.
Reaction product reacted for a time. NCO 25.5%, viscosity 300 cps / 25 ° C. (9) Isocyanate B 4,4′-MDI 50 parts by weight (0.400 equivalent) and polymeric MDI 50 parts by weight (0.369 equivalent) to Monool A 5.2. Add parts by weight (0.0051 equivalents), 8
Reaction product reacted at 0 ° C. for 2 hours. NCO 30.5
%, Viscosity 150 cps / 25 ° C. (10) 50 parts by weight (0.400 equivalent) of isocyanate C 4,4′-MDI and 50 parts by weight (0.369 equivalent) of polymeric MDI and 20 parts by weight of polyol II (0.0086 equivalent). ) And 5.2 parts by weight of Monool A (0.0051 equivalents), 80 ° C
The reaction product reacted for 2 hours. NCO 25.1%,
Viscosity 200 cps / 25 ° C (11) Isocyanate D 4,4'-MDI 30 parts by weight (0.240 equivalent) and uretonimine modified MDI 20 parts by weight (0.1348 equivalent)
And 20 parts by weight of polyol II (0.0086 equivalents) and 10.0 parts by weight of monool B (0.01 equivalents) to 50 parts by weight (0.369 equivalents) of polymeric MDI, 8
Reaction product reacted at 0 ° C. for 2 hours. NCO 23.2
%, Viscosity 350 cps / 25 ° C. Tables 1 to 4 collectively show the results of Comparative Examples and Examples.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

Comparative Examples 1, 2, 3, 4 Resin components and isocyanate components were mixed in the proportions shown in Table 1, and free foaming (free blowing) at 25 ° C.
Then, a 50 × 200 × 200 mm rectangular mold was formed. In free foaming, the time at which foaming starts (cream time), the foam was pierced with a stick, the time when the foam pulled a thread when the stick was pulled up (gel time), and the time until foaming ended (rise time) were measured. In addition, the foam state was observed 1 hour after foaming. The results are shown in Table 2. Foam shrinkage occurred with both free foaming and molding. The curability was demolded 3 minutes after injection into the mold, and the quality was judged by the presence or absence of finger marks after finger touch. After 30 minutes of demolding, the touch was subjected to a sensory test with a finger to determine the degree of closeness of the foam. Regarding the touch and the curability, the quality was evaluated by ◎ ○ △ x. The results are shown in Table 2, and as shown in Comparative Example 2, the polymer polyol is effective in preventing shrinkage, but it is not sufficient. In addition, the feel becomes worse. On the other hand, Comparative Examples 3 and 4, which contained only monool, were effective in preventing shrinkage, but were too hard and had a poor feel.

Examples 1, 2, 3, 4 In the same manner as in Comparative Examples 1 to 4, the resin component and the isocyanate component were mixed in the proportions shown in Table 3, and free foaming (free blowing) at 25 ° C. was performed. X200 x200
A mm rectangular mold was formed. The results are shown in Table 4, and in the system in which the polyol and the monol were used in combination, no shrinkage occurred and the feel was good.

Examples 5, 6 Examples 1 and 2 were combined with a headrest mold, and integrally molded with a soft vinyl chloride skin containing a core material. The results are shown in Table 4, and the molded product did not shrink, and the touch was good.

[0026]

According to the present invention, a semi-rigid urethane foam having a low density and capable of non-crushing can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C08L 75:04 (72) Inventor Yoshio Yoshida 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd. Company (72) Inventor Tsutomu Kumazawa 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (4)

[Claims] 1. A semi-rigid foam obtained by reacting an isocyanate component with a resin component containing a polyol, water and other auxiliaries, wherein the isocyanate component is
Aromatic polyisocyanate (A), molecular weight 700-12
000 polyol (B) and a monool (C) having a molecular weight of 35 to 1000, wherein the equivalent ratio (C / A) of monool (C) and aromatic polyisocyanate (A) is 0. 0.01 to 0.2 and the equivalent ratio of the polyol (B) and the aromatic polyisocyanate (A) (B
/ A) is 0.01 to 0.2. 2. The method for producing a semi-rigid urethane foam according to claim 1, wherein the aromatic polyisocyanate (A) is a polyisocyanate containing diphenylmethane diisocyanate as a main component. 3. The method for producing a semi-rigid urethane foam according to claim 1, wherein the monool (C) is an adduct of alcohol and alkylene oxide. 4. The molding method is an integral molding method of urethane and a soft polyvinyl chloride skin.
A method for producing the semi-rigid urethane foam described.