1. According to usage: internal release agent and external release agent;
2. According to service life: conventional release agent, semi permanent release agent;
3. According to the form classification: solvent type release agent, water-based mold release agent, solvent-free mold release agent, powder mold release agent, paste mold release agent
4. According to the active substance classification:
① Silicon series – mainly silicone compounds, silicone oil, silicone resin methyl branched chain silicone oil, methyl silicone oil, emulsified methyl silicone oil, hydrogen containing methyl silicone oil, silicone grease, silicone resin, silicone rubber, silicone rubber toluene solution
② Wax series: plant, animal, synthetic paraffin; microcrystalline paraffin; polyethylene wax, etc.
③ Fluorine series – the best isolation performance, less pollution to mold, but high cost, polytetrafluoroethylene, fluororesin powder, fluororesin coating, etc
④ Surfactant series — metal soap (anionic), EO, Po derivatives (nonionic)
⑤ Inorganic powder series — talc, mica, clay, clay, etc
⑥ Polyether series – polyether and grease mixture, heat resistance and good chemical properties, are mostly used in some rubber industry with limited silicone oil. The cost is higher than that of silicone oil series.
What are the causes of silicone oil yellowing?
There are different opinions on the causes of silicone oil yellowing. Some believe that it is caused by the trace metal elements and NO-3 contained in raw materials and additives for the production of dimethylsilicone oil; some believe that it is caused by the decomposition of diaChinayl peroxide, which leads to the condensation and dehydration of α – hydroxybutyraldehyde and the formation of conjugated compounds; some believe that the pH value of silica affects the yellowing of silicone rubber.
The following are the methods to improve the yellowing of silicone oil:
1. Adding an anti yellowing agent called pyrophosphoric acid can enhance the anti yellowing ability of the compound on the basis of not reducing the physical and mechanical properties of the compound.
2. Adding organic surfactant into silica can control the size of secondary particles, and effectively control the yellowing degree of dimethylsilicone oil under the action of compound anti yellowing agent.
3. Adding a paste like double 2,5 vulcanizing agent with high content of hydrogen silicone oil to improve the anti yellowing effect of silicone rubber, improve the transparency of dimethylsilicone oil and prevent the splashing of curing agent.