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1, compound preparation and pouring process diagram (polyester TDI MOCA for example) 2

3, the production process

(1) for poly preparation for example

The polyester polyol dehydration (held in dewatering kettle): Mn.2000 (hydroxyl value 53~59, mgKOH/g, melting point 40~50 ℃) polyester, in a stirred stainless steel or enamel kettle for heating and melting, dehydration temperature 100~140 ℃ (polyether 100~110 ℃), the residual pressure 5mmHg held vacuum dewatering water 30~60 minutes, the the water content of < 0.05% (from the mirror can be observed in dehydrated environment). In order to make a tank of liquid filling degassed, intermittent stop stirring device, a vacuum period, can stop the crashed tank heating, the temperature dropped to 70~80 ℃.

The prepolymer synthesis (held in echo kettle): product depends on the properties of the raw materials used and the formulation and processing technology. According to the performance requirements, such as temperature, environmental stress and contact media and use life suitable raw materials. According to the requirements of the selected suitable hardness ratio and process conditions (such as mixed temperature, casting and demoulding time and curing conditions). To the quality to ensure that the polyester polymer, dehydration and prepolymer synthesis best held not in the same reactor, prepolymer synthesis immediately held in dry nitrogen. Guard fell violently, fast temperature rising, must be equipped with cooling device. Initiate feeding order: first add TDI with polyester, such as echo is intense, polyester can be divided in the echo process, stable, then easy to control temperature, synthesis of prepolymer in the divorce of cyanate ester monomer content is low, the layout is regular. Keep it at 80 ± 5 ℃, after 1~2 hours, analysis of isocyanate content. At about conditions can also purchase to meet the requirements of domestic and foreign brands of prepolymer.

The prepolymer degassing (A materials can be held in polymer synthesis involved kettle or casting machine in a given in): at 85 ± 5 ℃ and the residual pressure of 5mmHg degassing 30~60 minutes.

(2) casting machine casting:

Key: ① skill casting machine casting polyurethane elastomer (CPU) in the production of key configuration, the tension skill requirements are as follows:

A, precision ratio, measurement of high precision metering pump solid: admission temperature pressure and precision transmission, control and performance of device, the measurement precision is up to ± 0.5%.

B, mixed evenly, does not produce the bubble: high speed mixed head receiving special layout, when the two component solution viscosity and composition vary greatly, can also ensure that the mixed symmetry, the production of products of macro no bubbles, and control maneuver, convenient operation.

C, temperature is stable, accurate and reliable: temperature change will affect the viscosity of liquid liquid, pressure, the precision and the mixed ratio, making wind quantity can not be stable. Especially the B component (MOCA) is a solid at room temperature, if the temperature is too low will feed junction died not operating temperature is too high, the material is easy to change and the influence of wind quantity. Thermal oil circulation system, electric heating liquid, metering pump and pouring head, by the intelligent time proportional temperature controller with digital display temperature control at.

The pouring process: in the B tank in MOCA (melting temperature higher than 110 DEG C) heating system components, the A, B material arrives at the required temperature and their circulation, A material such as necessary to hold the vacuum degassing, arrive to poly bubble free body. According to the formula of requirements through regulating metering pump speed and capacity, make A, B speculates as requirements of the mixed ratio. Start pouring button, then A, B material in the pouring head mixed chamber through the high-speed mixed to mixed symmetry, when the crowding out of the mixed material in a transparent hose without bubbles can go die casting (die and roller core had been pretreated with punishment, and heating to 80~110 DEG C). When pouring two times interval is longer (higher than the kettle life 1/2) with detergents (dichloromethane or trichloroethylene) held on mixed cavity automatic washing (automatically controlled by a computer program controller). When pouring stop, A, B solution is automatically to their circulation state, back to the material tank.

(3) curing and after treatment:

The molding vulcanized (models of sulfide), cots in release before the mold curing process, based on its chemical structure is not damaged under the high temperature, as far as possible, in order to speed up the chain extension crosslinking answered, shrinkage release time, improve the utilization rate of mold and configuration, often in 100~120 ℃, 60~120min is appropriate.

after vulcanization process: refers to the continuous heating vulcanized rubber roller after demoulding, a temperature slightly below the molding vulcanization, 90~110 ℃, 3~10 hours.

The appearance and processing: according to the requirement of a turning or grinding in machining configuration.