JPH07149871A - Curable resin composition and production of curable resin from the same composition - Google Patents

Abstract

PURPOSE:To provide a curable resin composition composed of a specified carbodiimide-modified liquid diphenylmethane diisocyanate, a polyether polyol having a specified molecular weight and others, excellent in shelf life and compatibility and useful for a belt, a sealing material, etc. CONSTITUTION:This curable resin composition is composed of (A) a carbodiimide-modified liquid diphenylmethane diisocyanate having 9.0 to 17.0wt.% ratio of modification with carbodiimide, (B) a polyether polyol having 600 to 4000 molecular weight, e.g. polypropylene ether glycol and further (C) a low-molecular active hydrogen group-containing compound having 62 to 600 molecular weight, e.g. ethylene glycol and containing an additive as necessary. In addition, a curable resin can be obtained by pouring this composition into a mold of 30 to 90 deg.C and curing it for 5 to 12hr.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a curable resin composition for cast urethane elastomers. It relates to a resin obtained by using an isocyanate.

[0002]

2. Description of the Related Art The molding technology for cast urethane elastomers is roughly classified into two types, usually the one-shot method and the prepolymer method.
It is divided into two. Conventionally, the one-shot method has the following features. Compared with the prepolymer method, the number of steps is small and it is economical. Mixing is easy because the viscosity of each component liquid is low and the difference in viscosity is small. It can be used for low hardness without using a chain extender.

Carbodiimide-modified liquid MDI derived from diphenylmethane diisocyanate (hereinafter abbreviated as MDI) and having excellent storage stability at room temperature (carbodiimide modification rate, approximately 30%, hereinafter abbreviated as liquid MDI) and polyether polyol In the case of producing a cast urethane elastomer obtained by mixing with a polyol containing as a main component, the compatibility between the two is poor, and it is difficult to obtain a uniform mixture, so that a good elastomer is not obtained. On the other hand, a cast urethane elastomer obtained by mixing 2,4′-MDI and a polyol whose main component is a polyether polyol at room temperature is inferior in storage stability of 4,4′-MDI at room temperature. There is a technical problem.

The one-shot system of MDI and polyether polyol has a good working environment because polyether polyol has a relatively low viscosity and is inexpensive, and MDI has a lower vapor pressure than tolylene diisocyanate. There are features such as being.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have found that the casting stability of liquid MDI at room temperature in a cast urethane elastomer obtained by mixing liquid MDI with a polyol whose main component is polyether polyol. As a result of intensive studies for maintaining stable properties and improving the mixing property with polyol to obtain stable physical properties, by using liquid MDI having a carbodiimide modification ratio within a specific range, storage stability at room temperature is improved. Therefore, the present invention has been achieved by finding that the mixing ratio with the polyol is improved and the mixing property with the polyol is improved.

[0006]

That is, according to the present invention, a liquid MDI as an organic polyisocyanate and a molecular weight of 600 to 40 are used.
A polyether urethane polyol of No. 00, and optionally additives, which is a liquid M
The curable resin composition has a carbodiimidization modification rate of DI of 9.0 to 17.0% by weight.

The present invention is a cast urethane elastomer comprising liquid MDI as an organic polyisocyanate, a polyether polyol having a molecular weight of 600 to 4000, a low molecular weight active hydrogen group-containing compound having a molecular weight of 62 to 600 or less, and an additive as required. The liquid MDI has a carbodiimidization modification rate of 9.0 to 17.0% by weight, and the low molecular weight active hydrogen group-containing compound is 30 parts by weight or less with respect to 100 parts by weight of the polyether polyol. It is a curable resin composition.

The method for producing a curable resin of the present invention is characterized in that the curable resin compositions described above are mixed, poured into a mold at 30 to 90 ° C. and cured for 5 to 12 hours. Is a manufacturing method.

The organic polyisocyanate which can be used in the present invention is a liquid MDI obtained by adding a carbodiimidization modification catalyst to MDI. Carbodiimidation modification rate is 9.0
˜17.0% by weight. In this case, when the modification rate is 9.0% by weight or less, the storage stability is poor, and when the modification rate is 17.0% by weight or more, the compatibility with the polyol is poor and the physical properties of the elastomer are poor.

The polyether polyol which can be used in the present invention is a polyol whose main component is polypropylene ether glycol having a molecular weight of 600 to 4000, and more specifically, polypropylene ether glycol, a copolymer of propylene oxide and ethylene oxide, trimethylolpropane. Polypropylene ether glycol as an initiator, a copolymer of propylene oxide and ethylene oxide as an initiator of trimethylolpropane,
Examples thereof include polypropylene ether glycol using glycerin as an initiator, copolymers of polypropylene oxide and ethylene oxide using glycerin as an initiator, and mixtures of these polyether polyols. The preferred molecular weight is 700 to 3000.

Examples of the low molecular weight active hydrogen group-containing compound which can be used in the present invention include glycols such as ethylene glycol, propanediol, butanediol, diethylene glycol and dipropylene glycol having a molecular weight of 62 to 600 and glycerin and trimethylolpropane. Polyhydric alcohols may be used alone or as a mixture of two or more. The low molecular weight active hydrogen group-containing compound is used in a ratio of 30 parts by weight or less based on 100 parts by weight of the above polyether polyol or a mixture of the above polyether polyol. The molecular weight of these mixtures is usually 150-40.
00. The preferred use ratio of the polyether polyol and the low molecular weight active hydrogen group-containing compound is 100% of the polyol.
It is 20 parts by weight or less with respect to parts by weight.

Additives used as necessary include
Colorants, flame retardants, defoamers, antioxidants, UV absorbers,
A conductivity imparting agent, a filler and the like can be used. Examples of the filler include milled glass fiber and wollastonite.

Organic polyisocyanate of the present invention (Liquid A)
And the polyether polyol (B liquid) are mixed at a ratio of the active hydrogen group concentration of the B liquid and the isocyanate group concentration of the A liquid, that is, the active hydrogen group / NCO group equivalent ratio is 0.8 to.
It is blended to be 1.20. If necessary, reaction catalysts, additives, etc. may be used. In principle, the crosslinking is carried out at room temperature, but it is also possible to inject the mixed solution of the liquid A and the liquid B into a preheated mold and carry out the reactive crosslinking at a temperature of 40 to 160 ° C.
After this primary cross-linking, the urethane cross-linking is carried out by secondary cross-linking and aging according to a conventional method to obtain a urethane elastomer.

[0014]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples. "Parts" and "%" in the examples are "parts by weight" and "% by weight", respectively. The carbodiimide modification rate was determined by gel permeation chromatography (GPC).

Example 1 Melted MDI (manufactured by Nippon Polyurethane Industry, Millionate MT) and liquid MDI (manufactured by Nippon Polyurethane Industry, Millionate MTL-C, carbodiimide modification rate; 33.
4%) was mixed so that the weight ratio of MDI / liquid MDI was 1.0, and liquid MDI having a carbodiimide modification ratio of 16.7% was synthesized. This liquid MDI and polypropylene ether glycol (P-1000, manufactured by Asahi Denka Kogyo Co., Ltd., average molecular weight 1000, hydroxyl value 112 KOHmg / g) were blended so that the active hydrogen group / NCO group equivalent ratio was 0.98, and this mixture was prepared. Was poured into a mold preheated to 40 ° C. and cured at 40 ° C. for 10 hours. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer. Physical property values were measured according to JIS K6301. Regarding the storage stability of liquid MDI obtained by mixing MDI and liquid MDI at room temperature, the state of the liquid after storage for 24 hours in a dry state at an ambient temperature of 25 ° C. was visually confirmed. The mixing property of the liquid MDI and the polypropylene ether glycol was measured by measuring the time from the start of stirring the two liquids to the time when the mixed liquid became a visually transparent and homogeneous phase. The results are shown in Table 1.

Example 2 Melted MDI (manufactured by Nippon Polyurethane Industry, Millionate MT) and liquid MDI (manufactured by Nippon Polyurethane Industry, Millionate MTL-C, carbodiimide modification rate; 33.
4%) was mixed so that the weight ratio of MDI / liquid MDI was 2.3, and liquid MDI having a carbodiimide modification ratio of 10.0% was synthesized. This liquid MDI and polypropylene ether glycol (P-1000, manufactured by Asahi Denka Kogyo Co., Ltd., average molecular weight 1000, hydroxyl value 112 KOHmg / g) were blended so that the active hydrogen group / NCO group equivalent ratio was 0.98, and this mixture was prepared. Was poured into a mold preheated to 40 ° C. and cured at 40 ° C. for 10 hours. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer. Physical properties and the like of this polyurethane elastomer were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 3 Melted MDI (manufactured by Nippon Polyurethane Industry, Millionate MT) and liquid MDI (manufactured by Nippon Polyurethane Industry, Millionate MTL-C, carbodiimide modification rate; 33.
4%) was mixed so that the weight ratio of MDI / liquid MDI was 2.3, and liquid MDI having a carbodiimide modification ratio of 10.0% was synthesized. Polypropylene ether glycol (Asahi Denka Kogyo, P-1000, average molecular weight 100)
0, a hydroxyl value of 112 KOHmg / g) and 1,4-butanediol were mixed so that 14.5 parts of 1,4-butanediol was mixed with 100 parts of polypropylene ether glycol to obtain a mixed polyol. This liquid MDI
And mixed polyol were mixed so that the active hydrogen group / NCO group equivalent ratio was 0.98, and this mixture was poured into a mold preheated to 40 ° C. and cured at 40 ° C. for 10 hours. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer. Physical properties and the like of this polyurethane elastomer were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 4 3000 parts of MDI was heated to 90 ° C. with stirring in a 3000 ml four-necked flask, and 0.3 part of catalyst (3-methyl-1-phenyl-3-phospholen-1-oxide was added to 1 part).
10 ppm of isocyanate as 0% xylene solution
) Was added for carbodiimidization. 4 at 90 ° C
When the NCO concentration was measured after the time reaction,
The content rate was 31.5%. After that, 0.088 parts of trichlorosilane was added and mixed with stirring to obtain liquid MDI.
The carbodiimide modification ratio was 16.0%. This liquid M
DI and polypropylene ether glycol (Asahi Denka Kogyo, P-700, average molecular weight 700, hydroxyl value 160K
OHmg / g) has an active hydrogen group / NCO group equivalent ratio of 0.9
The mixture was blended so as to be 8, and this mixed solution was poured into a mold preheated to 40 ° C. and cured at 40 ° C. for 10 hours. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer. Physical property values are JIS K
6301 was measured. Regarding the storage stability of liquid MDI obtained by mixing MDI and liquid MDI at room temperature, the state of the liquid after storage for 24 hours in a dry state at an ambient temperature of 25 ° C. was visually confirmed. The mixing property of the liquid MDI and the polypropylene ether glycol was measured by measuring the time from the start of stirring the two liquids to the time when the mixed liquid became a visually transparent and homogeneous phase. The results are shown in Table 1.

Example 5 3000 parts of MDI was heated to 90 ° C. with stirring in a 3000 ml four-necked flask, and 0.3 part of catalyst (3-methyl-1-phenyl-3-phospholen-1-oxide was added to 1 part).
10 ppm of isocyanate as 0% xylene solution
) Was added for carbodiimidization. 4 at 90 ° C
When the NCO concentration was measured after the time reaction,
The content rate was 32.1%. After that, 0.088 parts of trichlorosilane was added and mixed with stirring to obtain liquid MDI.
The carbodiimide modification rate was 13.0%. This liquid M
DI and polypropylene ether glycol (Asahi Denka Kogyo, P-1000, average molecular weight 1000, hydroxyl value 11
2 KOHmg / g) was mixed so that the active hydrogen group / NCO group equivalent ratio was 0.98, and this mixture was poured into a mold preheated to 40 ° C. and cured at 40 ° C. for 10 hours. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer. Physical properties and the like of this polyurethane elastomer were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 6 3000 parts of MDI were heated to 90 ° C. with stirring in a 3000 ml four-necked flask, and 0.3 part of catalyst (3-methyl-1-phenyl-3-phospholen-1-oxide was added to 1 part).
10 ppm of isocyanate as 0% xylene solution
) Was added for carbodiimidization. 4 at 90 ° C
When the NCO concentration was measured after the time reaction,
The content rate was 32.9%. After that, 0.088 parts of trichlorosilane was added and mixed with stirring to obtain liquid MDI.
The carbodiimide modification rate was 10.2%. Polypropylene ether glycol (P-200 manufactured by Asahi Denka Co., Ltd.
0, average molecular weight 2000, hydroxyl value 56.1 KOHmg
/ G) and 1,4-butanediol were mixed to 100 parts of polypropylene ether glycol to give 9.0 parts of 1,4-butanediol to obtain a mixed polyol. This liquid MDI and mix polyol were blended so that the active hydrogen group / NCO group equivalent ratio was 0.98, and this mixture was poured into a mold preheated to 40 ° C.
It was cured for 10 hours. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer.
Physical properties and the like of this polyurethane elastomer were measured in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 Liquid MDI (Millionate M manufactured by Nippon Polyurethane Industry Co., Ltd.)
TL-C, carbodiimide modification rate; 33.4%) and polypropylene ether glycol (P-1, manufactured by Asahi Denka Co., Ltd.)
000, average molecular weight 1000, hydroxyl value 112 KOHm
g / g) was mixed so that the active hydrogen group / NCO group equivalent ratio was 0.98, and this mixture was poured into a mold preheated to 40 ° C. and cured at 40 ° C. for 10 hours. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer. Physical properties and the like of this polyurethane elastomer were measured in the same manner as in Example 1. The results are shown in Table 2.
Shown in.

Comparative Example 2 Melted MDI (manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MT) and liquid MDI (manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MTL-C, carbodiimide modification rate; 33.
4%) was mixed at a MDI / liquid MDI weight ratio of 4.0 to synthesize liquid MDI having a carbodiimide modification ratio of 6.7%. This liquid MDI and polypropylene ether glycol (P-1000, manufactured by Asahi Denka Kogyo, average molecular weight 100
0, hydroxyl value 112 KOHmg / g) as active hydrogen group / N
The CO group equivalent ratio was 0.98, and the mixture was poured into a mold preheated to 40 ° C.
I did time cure. The resulting polyurethane was aged at room temperature for 1 week to obtain a polyurethane elastomer. Physical properties and the like of this polyurethane elastomer were measured in the same manner as in Example 1. The results are shown in Table 2.

[0023]

[Table 1]

[0024]

[Table 2]

Claims (3)

[Claims] 1. A cast urethane elastomer comprising a carbodiimide-modified liquid diphenylmethane diisocyanate as an organic polyisocyanate, a polyether polyol having a molecular weight of 600 to 4000, and optionally an additive, wherein the carbodiimide-modified liquid diphenylmethane diisocyanate is carbodiimidized. A curable resin composition having a modification rate of 9.0 to 17.0% by weight. 2. A cast urethane comprising an organic polyisocyanate, a carbodiimide-modified liquid diphenylmethane diisocyanate, a polyether polyol having a molecular weight of 600 to 4000, a low molecular weight active hydrogen group-containing compound having a molecular weight of 62 to 600 or less, and an additive if necessary. An elastomer, wherein the carbodiimide-modified liquid diphenylmethane diisocyanate has a carbodiimidization modification rate of 9.0 to 17.0% by weight, and 30 parts by weight or less of a low molecular weight active hydrogen group-containing compound with respect to 100 parts by weight of a polyether polyol. A curable resin composition comprising: 3. A method for producing a curable resin, which comprises mixing the curable resin composition according to claim 1 or 2 and injecting the mixture into a mold at 30 to 90 ° C. and curing for 5 to 12 hours.