Phenyl silicone oil is a type of modified organosilicon polymer with a siloxane (Si-O-Si) main chain, where some methyl groups are replaced by phenyl groups. The synergistic effect between phenyl and methyl groups in its molecular structure endows it with special properties different from ordinary dimethyl silicone oil, making it a core variety in the high-end organosilicon material system, widely suitable for harsh application scenarios such as high temperature, insulation, and optics. Compared with traditional silicone oil, the introduction of phenyl groups not only retains the weather resistance and hydrophobicity of polysiloxane, but also significantly improves high temperature resistance, refractive index, and compatibility, breaking the performance limitations of general-purpose silicone oil.
From a molecular structure perspective, the properties of phenyl silicone oil can be precisely regulated through phenyl substitution degree and substitution position: low phenyl substitution (phenyl content 5%-15%) products balance flexibility and high temperature resistance, with a long-term service temperature of up to 150℃; medium and high phenyl substitution (phenyl content 20%-50%) products have a refractive index increased to 1.48-1.53, excellent transparency, and high temperature resistance exceeding 250℃, and some special products can be used at above 300℃ for a short time. In addition, the aromatic ring structure of phenyl enhances intermolecular forces, improves the viscosity stability of the product, is not easy to solidify at low temperatures, and can maintain stable performance in a wide temperature range of -60℃ to 280℃, adapting to the needs of extreme environment operations.
Currently, the mainstream preparation process of phenyl silicone oil is hydrolysis polycondensation. Using methylphenyldichlorosilane and dimethyldichlorosilane as core monomers, hydrolysis reaction occurs in water-alcohol medium to generate silanol intermediates, which are then subjected to catalytic polycondensation, neutralization, removal of low-boiling substances, and filtration and refining to obtain the finished product. The traditional process has problems such as uneven monomer hydrolysis, wide product molecular weight distribution, and difficulty in precise control of phenyl substitution degree, leading to large fluctuations in product performance.
With technological innovation, the application of continuous hydrolysis polycondensation technology and new catalysts has effectively solved the above pain points. Adopting a segmented temperature-controlled hydrolysis process can control the monomer hydrolysis rate and reduce side reactions; selecting organotin and amine composite catalysts can precisely regulate the polycondensation process, control the deviation of phenyl substitution degree within ±2%, narrow the molecular weight distribution, and significantly improve the consistency of product performance. At the same time, the popularization of solvent-free production processes reduces volatile organic compound emissions, conforms to the requirements of green chemical development, and promotes the upgrading of phenyl silicone oil from general-purpose to high-end customized type, adapting to the needs of more special scenarios.