Low-hardness thermosetting polyurethane elastomer and production method thereof

A polyurethane elastomer, thermosetting technology, applied in the field of thermosetting polyurethane elastomers, can solve the problems of differential molding, low speed, exudation, etc.

Inactive Publication Date: 2007-05-16
BAYER MATERIALSCIENCE AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] In the technique of JP-A-8-151423, since the isocyanate-terminated prepolymer based on high-molecular-weight polyfunctional polypropylene glycol has high viscosity, polyurethane elastomers disadvantageously have difficult processability and easily cause poor molding sex
Because low-reactivity polyoxypropylene diol is used as a curing agent, the disadvantages of this technology are that the reaction has a low speed, molding should be performed at a relatively high mold temperature, and residual unreacted polyoxypropylene diol tends to cause bleeding
[0015] In the technique of JP-A-2003-252947, because the reaction between the isocyanate group-terminated prepolymer and the curing agent has a low speed, so that unreacted polyols tend to remain, this technique has the tendency to cause bleeding and requires a large amount of catalyst Disadvantages to increase curing rate and molding should be done at relatively high mold temperature

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0085] Isocyanate-terminated prepolymer F was prepared by reacting 150 parts of 4,4'-diphenylmethane diisocyanate with 850 parts of polyol A at 90° C. for 30 hours under a dry nitrogen atmosphere, followed by cooling. The resulting isocyanate-terminated prepolymer had an NCO content of 4.0% and a viscosity of 9,700 mPa.s / 25°C.

[0086] The curing agent was prepared by blending 10 parts Polyol C, 90 parts Polyol D, and 0.02 parts DBU Octylate.

[0087] 54 parts of prepolymer F controlled at 70°C and 100.02 parts of curing agent (the equivalent ratio of NCO group and hydroxyl group of the curing agent is 1.03) controlled at 25°C were mixed for 1 minute with a propeller mixer, and then poured into the In a hot metal mold at 80°C, and cured in a heating oven for 30 minutes and demolded. The pot life of the mixture is 5 minutes. The release molding was heated at 80° C. for 10 hours. In addition, after the mold was post-cured for 7 days in an atmosphere of 25° C. and 60% RH, the ...

Embodiment 2

[0089]In the same manner as in Example 1, isocyanate group-terminated prepolymer G was prepared by reacting 142 parts of 4,4'-diphenylmethane diisocyanate with 858 parts of polyol B. The obtained isocyanate-terminated prepolymer G had an NCO content of 4.0% and a viscosity of 15,000 mPa.s / 25°C.

[0090] A molded article was obtained in the same manner as in Example 1 except that Prepolymer G was used. The pot life of the mixture is 5 minutes. Table 3 shows the measurement results of physical properties of the obtained molded articles. JIS A hardness was 28 and compression set was 1.0%. In addition, the molded article showed no exudation. All the physical properties of the molded article reached the target.

Embodiment 3

[0092] In the same manner as in Example 1, an isocyanate group-terminated prepolymer was prepared by reacting 155.3 parts of polymethylene polyphenylisocyanate containing 65% by weight of 4,4'-diphenylmethane diisocyanate with 844.7 parts of polyol A. Object H. The resulting isocyanate-terminated prepolymer had an NCO content of 4.0% and a viscosity of 15,000 mPa.s / 25°C.

[0093] A molded article was obtained in the same manner as in Example 1 except that Prepolymer H was used. The pot life of the mixture is 5 minutes. Table 3 shows the measurement results of physical properties of the obtained moldings. JIS A hardness was 33 and compression set was 1.0%. The molded article showed no bleeding. All the physical properties of the molded article reached the target.

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Abstract

To give a low-hardness thermosetting polyurethane elastomer having a high curing rate, a low JIS A hardness of 10 to 40, a small compression set, a low moisture absorption, good dimensional stability and no bleeding property. A low-hardness thermosetting polyurethane elastomer can be produced by reacting a difunctional polyol having a degree of total unsaturation of at most 0.01 meq / g with 4,4'-diphenylmethane diisocyanate alone or a polymethylene polyphenyl polyisocyanate containing 4,4'-diphenylmethane diisocyanate to give (1) an isocyanate group-terminated prepolymer having a NCO content of 3 to 6% and then reacting the prepolymer with a difunctional or trifunctional polyol having a degree of total unsaturation of at most 0.01 meq / g or a mixture thereof.

Description

technical field [0001] The present invention relates to a thermosetting polyurethane elastomer having low hardness, such as a polyurethane elastomer molded article, and a method for producing the same. Background of the invention [0002] By utilizing excellent properties such as mechanical properties and rubber-like elasticity, thermosetting urethane elastomers are commonly used, for example, in parts of office automation (OA) equipment such as electrostatic rollers, developing rollers, transfer rollers and feeding rollers in copiers, facsimile machines, etc. paper roll. [0003] But thermosetting urethane elastomers used in these applications have been required to have good properties such as lower hardness (JIS A hardness: up to 40), smaller compression set, better dimensional stability and no exudation, and The elastomer is required. Along with good properties, production methods with good productivity are also required, so that in the production of thermosetting polyu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/10C08G18/48C08G18/76C08G18/20
CPCC08G18/7664C08G18/4866C08G18/10C08G18/2063C08G18/6677C08G18/16C08G18/48C08G18/76
Inventor 德重勤三条猛真野卓志
Owner BAYER MATERIALSCIENCE AG
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