Common Problems And Solutions Of Foamed Rubber

Problem 1: Insufficient foaming holes
1. It may be that there is a problem with the quality of the blowing agent, if this happens, we should first check the expiration date of the blowing agent to see if the blowing agent is within the service life.
2. It may be that the strength of the rubber material that can be molded is too low. At this time, we need to check whether the plasticity of the rubber is within the standard range, if the plasticity is too low, it should be supplemented and mixed refining, so that the plasticity can be increased, and the foaming holes can be increased.
3. The rubber is placed for too long or placed in a place with high temperature, so that the foaming agent volatilizes. In this case, the compound should be re-processed.
4. The vulcanization speed of the rubber compound is very fast, at this time, the formula of the rubber compound should be adjusted, and the critical temperature of the vulcanizing agent and the decomposition temperature of the foaming agent should be coordinated, so that the speed of the two can cooperate with each other to slow down the vulcanization speed.

Problem 2: Insufficient filling mold
1. The amount of rubber used is insufficient, at this time, the rubber strip should be weighed one by one, so as to ensure that the weight of the rubber material meets the standard.
2. It may be that the mold is not smooth enough or the mold has been used for a long time but the corresponding cleaning work has not been carried out, so that the rubber material is resisted when it flows. In this case, we should find a way to reduce the resistance and enhance the fluidity of the rubber compound.

Problem 3: The foaming hole is too large or too small to be uneven
1. If the foaming agent is agglomerate, the solution is to sieve the agglomerated particles, fully powder the coarse particles, and then fully mix them to disperse them evenly.
2. The compounding agent contains too much moisture or air and other impurities are mixed with the rubber compound. In this case, the excessive water in the compounding agent should be eliminated first, and the air and impurities in the rubber compound should be fully removed, so as to make them fully vulcanized.
3. It may be due to insufficient vulcanization, and the phenomenon of continued pores occurs after the pattern is formed. At this time, the conditions of the vulcanization process should be adjusted accordingly, and the amount of vulcanizing agent should be increased to meet the corresponding standards.

Common problem 4: Pervulcanization or undervulcanization
1. Pervulcanization generally has a discolored surface, small holes, high hardness, and cracked edges of the product, the cause of which is improper operation, or too high temperature, too long vulcanization time or instrument failure, should check whether there is a problem with each valve and instrument, and then strictly implement the operation rules.
2. When the under-vulcanization and vulcanization are insufficient, the internal pressure of the pores is greater than the external pressure after the mold is discharged, and if the rubber continues to be porous, the hardness will be too low, the strength will be poor, and the deformation will be large; In the worst case, the eyelet will be blasted. The instrument and valve should be checked for problems, and the operating rules should be strictly implemented.

Note: Control quality indicators of foamed products (1) apparent density, the smaller the better; (2) The mechanical strength is generally 0.5-1.6Mpa; (3) Static compression set; (4) Hardness; (5) impact elasticity; (6) Continuous motion fatigue; (7) Aging test (70 degrees * 70 hours; 100 degrees Celsius * 24 hours); (8) Low temperature test.