Rubber Chem Encyclopedia

Varieties and usage of mold release agents commonly used in reclaimed rubber products

Create Date:2021-11-09 13:32:53Click volume:4052

The mold release agent is the mold release lubricant, which is a kind of special performance lubricant, which can effectively prevent the polymer from sticking to the mold during processing. In fact, there are many types of release agents. Most of the release agents are substances with low surface tension, which can form a continuous anti-sticking film among the polymer and the mold. According to its mode of action, it can be divided into short-lived and semi-permanent. There are two situations of sexual demoulding. In the production process of reclaimed rubber products, using a release agent when necessary can effectively increase the product yield and avoid unnecessary losses.

1. Variety of release agent

Commonly used release agents can be divided into inorganic release agents, organic release agents and polymer release agents. Inorganic mold release agents include graphite powder, molybdenum disulfide, talc and other powders; common organic mold release agents 2YLYY119 include fatty acids, fatty acid soaps, paraffins, glycols, etc.; polymer mold release agents mainly include silicone (silicone oil) , Silicone rubber, silicone resin, polyvinyl alcohol, cellulose acetate and fluoroplastic powder, etc.), of which silicone is the most commonly used release agent.

2. Commonly used release agents

Commonly used release agents for rubber products include semi-permanent release agents and water emulsified silicone release agents.

(1) Semi-permanent release agent

The chemical component of the semi-permanent release agent is a hydrocarbon, which is prepared by mixing a film-forming hydrocarbon, a surfactant, and an anticorrosive agent into a uniform transparent liquid. This release agent can form a very sticky film on the surface of the mold, which can undergo multiple releases without being transferred to the surface of the rubber product. In actual production, the maximum temperature in the mold can reach about 250°C. When in use, the product can be sprayed on a dry and clean mold surface to form a thin, wet, and slippery film; it is mainly used in the manufacture of model products and rubber soles.

(2) Water emulsified silicone release agent

The water-emulsified silicone release agent is a white milky solution. The chemical composition is silicone oil and water. It is made by emulsifying water-soluble silicone oil and water in the presence of an emulsifier. It is a general-purpose release agent for rubber and is suitable for above 100°C. Release of the rubber industrial products at the molding temperature.

When reclaimed rubber products use water-emulsified silicone release agent, in order to obtain a better release effect, tests can be carried out in advance. For example, you can first dilute 1 part of water-emulsion silicone mold release agent with 30 parts of water (soft water or distilled water) for trial demolding, check the surface of the molded product, if the demolding effect is not good, increase the concentration of the mold release agent; if the demolding effect is not good Very good, you can continue to increase the amount of water to further dilute. For copper and iron molds, adding 0.02%-0.1% sodium nitrite to the dilution water can effectively prevent the mold from rusting.

In actual production, the commonly used mold release agents in the rubber product industry include wax-based paraffin, petrolatum, polyethylene wax, polyethylene glycol, etc., and soapy water, sodium oleate, and glycerin in surfactants. To improve the releasability of reclaimed rubber products, rubber product manufacturers must choose appropriate types of release agents according to actual needs to further improve the demolding effect and yield of reclaimed rubber products.

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