Polyurethane elastomer casting machineCan be used for TDI, MDI and other prepolymer amine crosslinking or alcohol crosslinking system of CPU products production, compared with manual casting, casting machine casting quality is stable, high efficiency, stable temperature control and accurate proportional flow rate.

The key points to be paid attention to in the processing of elastomer products are:

1. Temperature control

When synthesizing prepolymer, the temperature is controlled between 75-82. Higher temperature will degrade the performance of the synthesized prepolymer, while lower temperature will prolong the polymerization time.

When mixed with MOCA, the prepolymer temperature is controlled between 90 and 110. Higher temperature will reduce the hardness and strength of the product, while lower temperature will increase the viscosity of the polymer, which is not conducive to casting operation.

The curing time is controlled at 130, and high curing time will decompose MOCA, which is not conducive to crosslinking reaction, and increase other side reactions. Lower will extend the molding time.

The melting temperature of MOCA can only be controlled as soon as it is melted into liquid, otherwise the liquid MOCA will become darker and decompose, which will affect the product performance.

2. Time control

Synthesis reaction for 2h, intermittent vacuum for 2h.

Then it is sealed and stored at room temperature. The synthesis of prepolymer should not exceed 4h at 75 temperature, and even less than 2h at 100 temperature, otherwise the performance of the product will be reduced.

Pouring should be completed within 1-2min, because the stability period after mixing the prepolymer and MOCA is very short, generally only 4-5min, otherwise the mixture solidifies and cannot be poured.

Molding curing time according to the shape and size of the product, generally between 15 to 30 minutes, to ensure that the product molding. For large products, the time is longer, requiring 2-3h.

3. Degassing of prepolymer

Degassing is the key to the success or failure of casting polyurethane elastomers.

Generally, two steps are needed to be controlled. After the synthesis of prepolymer, 75 vacuum degassing is used to remove most of the gas in the prepolymer during standing.

The prepolymer needs to be heated to 100-110 and degassed at high temperature before mixing with MOCA.

At the same time, vacuum (-0.095mpa) degassing for 10min, take out and stir the bottom bubbles to the top, and then vacuum and degassing for 10min.

The gas in the prepolymer can be discharged clean before mixed casting product with vulcanizing agent.