Casting polyurethane elastomer as well as preparation method and application thereof

Abstract

The invention discloses a casting polyurethane elastomer as well as a preparation method and an application thereof. The casting material is composed of a component A and a component B with a mass ratio of 100 / (8-12), wherein the component A is composed of TODI, macromolecule polyalcohol and a catalyst and the component B is composed of a diamine chain extender and a three-functionality micromolecule alcohol chain extender. The TODI and the macromolecule polyalcohol are added to a reactor to be stirred and mixed; then, a reaction is carried out on the mixture for 1.5-2.5 hours at a temperature of 75-95 DEG C to obtain a prepolymer; the prepolymer is heated to 70-90 DEG C, the chain extender component is heated to 110-130 DEG C, the prepolymer and the chain extender component are mixed, stirred, degassed and cast into a mould with a temperature of 90-120 DEG C; the mould is demoulded after 20-40 minutes of curing at a temperature of 90-120 DEG C; and the demoulded product is cured for 16-24 hours at a temperature of 90-110 DEG C. The elastomer is suitable to serve as a sealing element for a medium high-pressure hydraulic system, a sealing element for a pneumatic system and high-performance roller wheels and rubber covered rollers.

Description

technical field [0001] The invention relates to a casting type polyurethane elastomer and a preparation method thereof, in particular to a material with good heat resistance, oil resistance and good mechanical properties that meets the requirements for use of seals, rollers, rubber rollers and the like. Background technique [0002] Polyurethane elastomers are widely used in mechanical hydraulic transmission systems, seals in pneumatic systems and automotive seals because of their wide hardness range, good mechanical properties, resilience properties, wear resistance, oil resistance, and aging resistance. Due to the different working conditions of the equipment and the different media to be sealed, the sealing materials are required to have different adaptability: such as high mechanical strength and hardness, good compressibility and resilience, wide operating temperature range, in hydraulic oil, lubricating oil It can work for a long time in such medium, its volume and har...

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Problems solved by technology

In US20060276612A1, a polyurethane sealing material with good oil resistance has been reported. The material uses polycaprolactone polyol with a molecular weight of 1000 and quantitative TODI synthetic ester group density of 25wt.%~35wt.%, carbamate group density It is 7wt.%~12wt.% mixing type polyurethane rubber, which is mixed with vulcanizing agent and added with carbon black and other additives. The hardness of the elastomer is 60~85A, which has excellent oil resistance, resilience and resistance Thermal properties, but its mechanical properties are poor, tensile strength <20MPa

US4186261 has introduced a kind of hydraulic system sealing material, and this material is to use TODI and molecular weight earlier to be the polycarbonate polyol synthesis prepolymer of 2000, then use 2,3-dibromo-1,4-butene diol and 1, 4-butanediol is prepared by mixed chain extension. Its hardness is 95A and has good oil resistance, especially for hydraulic oil containing phosphate ester. However, its mechanical properties and resilience are not ideal, and its tensile strength is less than 30MPa. , rebound rate <35%

Due to the poor mechanical properties of the above-mentioned sealing materials, their application in high-pressure hydraulic systems is limited

[0004] Parker Hannifin (www.parker.com / eps) of the United States uses TODI to produce a high-performance thermoplastic elastomer (P4500) for piston seals, seal rods, wear-resistant lining hydraulic system seals, and the rebound rate is 45%. , the tensile strength is 45MPa, but the heat resistance is poor, the compression set (70hrs / 100°C) is 47%, and the maximum service temperature is 107°C

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