As a silicone nonionic surfactant, polyether silicone oil plays a key role in the PU release process.Its molecular structure is achieved by grafting and copolymer of polyether chain and dimethylsiloxane, and it has low surface tension, chemical stability and biocompatibility. These characteristics make it the core component of PU mold release agent.


At the level of the release mechanism, polyether silicone oil is released through the dual effects of physical isolation and chemical inertness.The adhesion of PU material to the mold stems from the chemical reaction between the water film on the surface of the mold and the isocyanate, as well as the chemical bonding between polar groups.Polyether silicone oil forms a dense and smooth isolation film on the surface of the mold. The high bond of the silicon-oxygen bond can give the film excellent thermal stability, and the structure can still be maintained intact at a high temperature of 250℃.


The film layer neither reacts chemically with the PU raw material, but also has moderate adhesion to the mold to ensure that there is no residue on the surface of the product after release.For example, the mold release agent combined with methyl polysiloxane resin and alkyl titanate in the German patented technology can achieve 6 consecutive mold releases and stable product quality.


The molecular structure characteristics of polyether silicone oil directly affect the release effect.By adjusting the number of silicone oil links, the polyether EO/PO ratio and the terminal group, the surface tension and wettability can be customized.The low surface tension characteristic allows it to spread quickly on the surface of the mold to form a uniform isolation layer; the hydrophilicity of the polyether chain enhances its compatibility with the water-based release system.


In practical applications, when polyether silicone oil is used as an external mold release agent, a film with a thickness of 0.1-0.3µm can be formed on the surface of the mold through the spraying process. The film remains intact during the PU curing process, and the surface gloss of the product after release reaches more than 90%, and it does not affect the subsequent finishing process.


In terms of formula optimization, polyether silicone oil is often used in combination with silicone resins, titanates, etc.For example, the synergistic system of polysiloxane resin prepared from methyltrimethoxysilane and tetrapropyl titanate can significantly increase the number of mold releases to more than 5 times, while maintaining no cracks and no adhesion on the surface of the product.


In addition, the emulsifying properties of polyether silicone oil make it suitable for water-based mold release agent systems to avoid safety risks caused by organic solvents, and its adjustable cloud point characteristics make it stable in a wide temperature range of -70℃ to 320℃.


Judging from industrial application data, the production efficiency of PU products using polyether silicone oil-based mold release agents has been increased by more than 30%, and the scrap rate has been reduced to less than 2%.Its long-lasting mold release properties extend the mold cleaning cycle to 3 times that of traditional wax-based mold release agents, and it has no corrosive effect on the mold.


This performance advantage makes polyether silicone oil the preferred release agent component in the production of PU products such as high-rebound foams, elastomers, and shoe materials.