JP3335454B2 - Manufacturing method of semi-rigid urethane foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing semi-rigid urethane foams such as headrests, armrests, center consoles, rear consoles and the like used as interior materials for automobiles. The present invention relates to a method for producing a semi-rigid urethane foam.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a semi-rigid urethane foam, an integral molding method in which a soft polyvinyl chloride skin is mounted on a mold, a semi-rigid urethane stock solution is injected, and foaming and curing are performed has been used. . In recent years, urethane foam used particularly for interior materials of automobiles has been required to have a low density due to economic factors. However, when the density of the foaming agent is reduced by increasing the amount of water used, the cells generally tend to be closed cells. In particular, in the case of the integral molding method with the soft polyvinyl chloride skin and the core material, the crash after molding may occur. Since molding is impossible, there is a problem such as shrinkage after molding. In recent years, diphenylmethane diisocyanate (MDI) has been used due to the toxicity of tolylene diisocyanate (TDI). In the case of MDI, although the reactivity is excellent, a closed cell is used. There was a drawback that it was easy to become.
Conventionally, as a method of physically opening a closed cell,
Although a method of crashing and passing a foam between rolls is generally used, it was impossible to apply the method to an integral molding method including a core material such as a headrest. As a cell opener (foam breaker), a polymer polyol obtained by polymerizing acryl or styrene in a polyether polyol has been generally used. However, although it has an effect, it has a large settling property and a disadvantage that the density reduction is insufficient. was there. When the polymer polyol is used, the viscosity becomes high, and there is a problem that air is entrapped at the time of mixing and causes a void, and a feeling of the foam is deteriorated. 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) 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, to have a low density and not to require crushing after molding (non-crushing). An object of the present invention is to provide a method for producing a semi-rigid urethane foam and a method for integrally molding the same with a skin (usually made of soft vinyl chloride).

[0004]

The present inventors have conducted intensive studies on a method for producing a semi-rigid urethane foam having a low density and capable of non-crushing after demolding. It has been found that the use of the isocyanate component reacted with the above polyisocyanate gives a non-crushing, semi-rigid urethane foam excellent in feel and moldability, thereby completing 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 polyol, water and other auxiliaries, the isocyanate component is an aromatic polyisocyanate (A), and has a molecular weight of 700 to 12,000. Reaction product of a polyol (B) of the formula (I) and a monool (C) having a molecular weight of 550 to 1000, wherein the equivalent ratio (C / A) of the monool (C) and the aromatic polyisocyanate (A) is
Is 0.01 to 0.2, and the equivalent ratio (B / A) of the polyol (B) and the aromatic polyisocyanate (A) is 0.0
A method for producing a semi-rigid urethane foam, which is 1 to 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 monol (C) is an adduct of an alcohol and an alkylene oxide.

The polyol which can be used as the resin component of the present invention includes at least water, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, triethanolamine, ethylenediamine, tolylenediamine, diaminodiphenylmethane and the like. The polyether polyol is a mixture of two or more active hydrogen compounds as starting materials, and an alkylene oxide represented by propylene oxide, ethylene oxide, butylene oxide, or the like, alone or in combination. A polymer polyol obtained by graft-polymerizing acrylic or styrene in these polyether polyols, or a mixture of a polyether polyol and a polymer polyol, and one or more dibasic acids such as adipic acid and sebacic acid, and ethylene glycol , Propylene glycol, diethylene glycol, triethylene glycol, glycerin, trimethylolpropane, and other polyhydric alcohols. And a polycaprolactone polyol obtained by ring-opening polymerization of caprolactone. These polyols preferably have a molecular weight of 500 to 12,000, and particularly preferably a polyether polyol having two hydroxyl groups has a molecular weight of 1,000 to 5,000, and a polyether polyol having three hydroxyl groups has a molecular weight of 3,000 to 8,000. When the graft polyol is used, the amount used is desirably 30% by weight or less based on the total amount of all active hydrogen-containing compounds. If the amount of the graft polyol exceeds 30% by weight, the polyurethane becomes too hard, which is not preferable, and there is also a problem that 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 a monol with an excess of an 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 ), Ureton imine modified liquid MD
I (liquid MDI), and one or a mixture of two or more of polymethylene polyphenylene polyisocyanate (crude MDI). In particular, polyisocyanates containing MDI as a main component, such as crude MDI and liquid MDI
Or a mixture of two or more of these.

[0008] As the polyol (B) having a molecular weight of 700 to 12,000, the same polyol as the resin component polyol can be used. These polyols have a molecular weight of 500-1.
Preferably, the polyether polyol having two hydroxyl groups is 2000 to 5000, and the polyether polyol having three hydroxyl groups is preferably 3000 to 8000.

The monool (C) having a molecular weight of 100 to 2,000 is represented by one active hydrogen compound such as methanol, ethanol, isopropanol or stearyl alcohol as a starting material, which is represented by propylene oxide, ethylene oxide, butylene oxide and the like. Polyether polyols and mixtures of these alkylene oxides alone or in combination. Preferably, a monol having a molecular weight of 550 to 1000 obtained by adding ethylene oxide to methanol is used. 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 is lost.

In the production of 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 ( A) equivalent ratio (C)
/ A) is 0.01 to 0.2, and the equivalent ratio (B / A) of the polyol (B) to the aromatic polyisocyanate (A) is in the range of 0.01 to 0.2, which is more preferable. Has an equivalent ratio in the range of 0.02 to 0.1. When the equivalent ratio of the monool (C) and the aromatic polyisocyanate (A) is 0.01 or less, there is no foam shrinkage-preventing effect, and when it is 0.2 or more, the curing property is poor. The equivalent ratio of the polyol to the aromatic polyisocyanate (A) is 0.0
When it is 1 or less, the foam is too hard, and the feel becomes poor.
When it is 0.2 or more, the viscosity of the product is too high and molding is difficult. The order in which the polyol and the monol are added to the aromatic polyisocyanate may be simultaneous or may be separately synthesized and then mixed. Further, a part of the aromatic polyisocyanate may be mixed later.

Examples of the crosslinking agent include triethanolamine, diethanolamine, a compound obtained by adding propylene oxide and 2 to 3 moles of ethylene oxide to 1 mole of aniline, propylene oxide to 1 mole of ethylenediamine,
Compounds obtained by adding 4 to 5 moles of an alkylene oxide such as ethylene oxide

Water reacts with the aromatic isocyanate,
In addition to forming the polyurea component, its main purpose is to generate carbon dioxide and act as a foaming agent, and is an essential component. The amount used is 1 to 10 parts by weight based on 100 parts by weight of the polyol component. It is also possible to use a foaming agent other than water in combination.

The amine catalyst for foaming is, 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'-
Tetramethylpropylenediamine, 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 Azacyclic compounds such as', N'N "-pentamethyldiethylenetriamine, formate and other salts of triethylenediamine, oxylalkylene adducts of amino groups of primary and secondary amines, 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 of use is 0.1 to 10 parts by weight based on 100 parts by weight of the compound having active hydrogen.

The foam stabilizer is a conventionally known organic silicon-based activator, for example, L-520, L-520, 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
And SH-19 manufactured by Toray Silicon Co., Ltd.
0, SH-192, SH-194, SH-200, SR
X-253, SRX-274C, SF-2961, SF
-2962, SRX-280A, SRX-294A, etc., and F-114, F-1 manufactured by Shin-Etsu Silicone Co., Ltd.
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 TFA-4200 and TFA-4202 by Toshiba Silicone Co., Ltd.
The amount of these foam stabilizers used depends on the amount of compound 10 having active hydrogen.
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, Fyrol manufactured by Akzo Japan Use -6 or the like. In addition, a plasticizer, a stabilizer, a colorant, and the like can be added as needed.

The isocyanate index [NCO / equivalent ratio of active hydrogen-containing groups × 100] at the time of polyurethane production is 60
To 140, preferably 70 to 120, particularly preferably 8
0 to 110. For the production of polyurethane, commonly used production equipment can be used. Various foams can be produced in closed or open molds. The production of polyurethane is usually carried out by mixing and reacting raw materials using a low-pressure or high-pressure mechanical device. The production of the present invention is useful for producing a mold foam. It is also possible by RIM (reaction injection molding). The resulting polyurethane may be either a flexible or semi-rigid foam, but a semi-rigid foam is preferred. The resulting polyurethane has a density of 0.1.
It is preferably in the range of 03 to 0.08 g / cm ³ . If the density is less than 0.03 g / cm ³ , the moldability deteriorates, which is not preferable. If the density exceeds 0.08 g / cm ³ , it is not economically preferable. The semi-rigid urethane foam obtained by the present invention is mainly used for automobile interior parts, for example, crash pads, armrests, headrests and the like.

[0017]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. Note that, unless otherwise specified, the numbers in the examples represent parts by weight.

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, and POP36-20 (OH value: 20) manufactured by Mitsui Toatsu Chemicals, Inc. (2) Polyol I A polyol having an OH value of 24, obtained by adding PO to glycerin and finally adding EO by 15% by weight. (3) Polyol II A polyol having an OH value of 55 obtained by adding PO to glycerin. (4) Foam stabilizer SRX-274C manufactured by Toray Silicone Co., Ltd. (5) Catalyst Kaorizer No. 1; Tetramethylhexamethylenediamine DABCO33LV; Triethylenediamine 33
% DPG solution (6) Monool A OH value of ethylene oxide added to methanol 102
Uniol 550 manufactured by NOF Corporation. (7) Monool B Monool having an OH value of 56 obtained by adding ethylene oxide to methanol, and Uniol 1000 manufactured by NOF Corporation. (8) Isocyanate A 50 parts by weight (0.400 equivalents) of 4,4′-MDI and 50 parts by weight (0.369 equivalents) of polymeric MDI were mixed with 20 parts by weight of polyol II (0.0086 equivalents) at 80 ° C.
Reaction product reacted for hours. NCO 25.5%, viscosity 300 cps / 25 ° C. (9) Monool A 5.2 in 50 parts by weight (0.400 equivalent) of isocyanate B 4,4′-MDI and 50 parts by weight (0.369 equivalent) of polymeric MDI. 8 parts by weight (0.0051 equivalent)
Reaction product reacted at 0 ° C. for 2 hours. NCO 30.5
%, Viscosity 150 cps / 25 ° C. (10) Isocyanate C 50 parts by weight of 4,4′-MDI (0.400 equivalents) and 50 parts by weight of polymeric MDI (0.369 equivalents) are added to 20 parts by weight of polyol II (0.0086 equivalents). ) And 5.2 parts by weight (0.0051 equivalents) of Monool A,
Reaction product 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 (0.0086 equivalents) of polyol II and 10.0 parts by weight (0.01 equivalents) of Monool B were added to 50 parts by weight (0.369 equivalents) of polymeric MDI,
Reaction product reacted at 0 ° C. for 2 hours. NCO 23.2
%, Viscosity 350 cps / 25 ° C. The results of Comparative Examples and Examples are summarized in Tables 1 to 4.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

Comparative Examples 1, 2, 3, 4 Resin component and isocyanate component were mixed at the ratios shown in Table 1, and free foaming (free blowing) at 25 ° C.
And a 50 × 200 × 200 mm rectangular mold was formed. In the free foaming, the time required for foaming to start (cream time), the time required for the foam to pull a thread when the rod was pierced and the rod pulled up (gel time), and the time required for foaming to end (rise time) were measured. Further, the foam state one hour after foaming was observed. Table 2 shows the results. Foam shrinkage occurred for both free foaming and molding. The curing property was released from the mold 3 minutes after injection, and the quality was judged based on the presence or absence of finger marks (finger nails) after touching. After 30 minutes from the demolding, the feeling was evaluated by sensory inspection of the degree of closing of the foam by finger touch. Regarding the feel and the curing property, the quality was evaluated as △ ○ △ ×. The results are as shown in Table 2. As shown in Comparative Example 2, the polymer polyol is effective in preventing shrinkage, but is not sufficient. In addition, the feeling becomes worse. On the other hand, Comparative Examples 3 and 4 containing only monool were effective in preventing shrinkage, but had too high hardness and poor feel.

Examples 1, 2, 3, 4 Resin components and isocyanate components were mixed in the proportions shown in Table 3 in the same manner as in Comparative Examples 1 to 4, and free foaming (free blowing) at 25 ° C. × 200 × 200
mm rectangular mold was formed. The results are shown in Table 4. In the system in which the polyol and the monol were used in combination, no shrinkage occurred and the feel was good.

Examples 5 and 6 Using the headrest actual molds in Examples 1 and 2 and forming a core material, the molding was performed integrally with the soft vinyl chloride skin. The results are as shown in Table 4. The molded article did not shrink and had a good feel.

[0026]

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

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Yoshida 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Tsutomu Kumazawa 1190 Kasama-cho, Sakae-ku, Yokohama-shi Kanagawa Prefecture Examiner Takeshi Sato within Co., Ltd. (56) References JP-A-4-65416 (JP, A) JP-A-60-219220 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G08G 18/00-18/87

Claims (3)

(57) [Claims] 1. A semi-rigid foam obtained by reacting an isocyanate component with a resin component containing polyol, water and other auxiliaries, wherein the isocyanate component comprises:
Aromatic polyisocyanate (A), molecular weight 700 to 12
000 polyol (B) and a molecular weight of 550 to 1000
Wherein the equivalent ratio (C / A) of the monool (C) to the aromatic polyisocyanate (A) is 0.01 to 0.2, and the polyol ( B) and the equivalent ratio of aromatic polyisocyanate (A) (B
/ A) is 0.01 to 0.2, a method for producing a semi-rigid urethane foam. 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 monol (C) is an adduct of an alcohol and an alkylene oxide.