What is rubber foam? Rubber foaming refers to the treatment of rubber with a specific foaming agent so that the rubber has characteristic properties.

What are the common problems in rubber foaming? How to solve it?

Problem 1: Insufficient foaming holes

1. There may be a problem with the quality of the foaming agent. If this happens, we must first check the service life of the foaming agent to see if the foaming agent is within the service life.

2. It may be that the strength of the rubber compound is too low. At this time, we need to check whether the plasticity of the rubber compound is within the standard range. If the plasticity is too low, supplementary mixing and refining should be carried out, which can increase the plasticity and increase the number of foam cells.

3. The rubber compound is placed for too long or placed in a place with high temperature to cause the foaming agent to volatilize. In this case, the compound should be reprocessed.

4. The speed of vulcanization of the rubber compound is very fast. At this time, the formula of the rubber compound should be adjusted to coordinate the critical temperature of the vulcanizing agent and the decomposition temperature of the foaming agent, so that the speed of the two can be coordinated 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 strips should be weighed one by one to ensure that the weight of the rubber material meets the standard.

2. It may be that the mold is not clean enough or the mold has been used for a long time without corresponding cleaning work, so that the rubber material is resisted when it flows. In this case, we should find a way to reduce the resistance to enhance the fluidity of the rubber.

Problem 3: The unevenness of the foaming holes is too large or too small

1. The foaming agent has agglomeration phenomenon. The solution is to sieve the agglomerated particles, fully pulverize the relatively coarse particles, and then fully knead them to make them evenly dispersed.

2. The compounding agent contains too much moisture or air and other impurities are mixed in the rubber compound. In this case, the excess water in the compounding agent should be removed 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 continuous pores after the pattern is formed. At this time, the conditions of the vulcanization process should be adjusted accordingly, and the use of the vulcanizing agent should be increased to meet the corresponding standards.

Common problem four: over-vulcanization or under-vulcanization

1. Over-vulcanization generally has discoloration on the surface, small holes, high hardness, and cracks on the edge of the product. The cause is improper operation, or high temperature, too long vulcanization time or instrument failure. Check whether there are problems with each valve and instrument. Furthermore, the operating rules must be strictly enforced.

2. When under-vulcanization and vulcanization are insufficient, the internal pressure of the pores is greater than the external pressure after the mold is ejected. If the rubber compound continues to pore, the hardness will be too low, the strength will be poor, and the deformation will be large; Instruments and valves should be checked for problems, and operating rules should be strictly enforced.

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 permanent deformation; (4) Hardness; (5) Impact elasticity ; (6) Continuous dynamic fatigue; (7) Aging test (70 degrees * 70 hours; 100 degrees * 24 hours); (8) Low temperature test.