Effect of Mass Fraction of Silane Coupling Agents on Properties of Emulsion and Film

1. Influence of the mass fraction of silane coupling agents on the properties of emulsion and film

Hydrophilic groups are introduced into the PU molecular chain and then the silane coupling agents disperse the PU molecules in water to form a stable dispersion through the hydrophilicity of its hydrophilic groups, which forms self-emulsifying PU. Then the polyamine group reacts with the residual isocyanate to extend the chain, and the silyl group of the silane coupling agents undergoes hydrolysis and polycondensation to cross-link the system, thus to realizes the internal cross-linking of the system during the post-chain extension, without affecting the dispersion of the prepolymer. Basic properties of the synthesized silicone-modified aqueous polyurethane emulsions. With the increase of the mass fraction of silane coupling agents, the emulsion changed from almost transparent liquid to white gradually, and the average particle size of the emulsion gradually increased. At the same time, except for the mass fraction of silane coupling agents of 8.9%, the emulsions maintained good dispersion stability.

The magnification of the TEM pictures of the latex particle morphology and structure of the modified aqueous polyurethane emulsion synthesized under different mass fractions of silane coupling agents is 100,000 times. The latex particles in all emulsions are irregular in shape. Without the addition of silane coupling agents, the particle size of the latex particles is very small, and the agglomeration is obvious. The same is true when the mass fraction of the silane coupling agents is 1.9%. The particle size is not large, and there is also agglomeration. When the mass fraction of the silane coupling agents is 7.6%, the basically spherical latex particles increase, and the particle size also increases significantly.

2. Application of silane coupling agents in the adhesive industry

Adhesion problems that cannot be solved by ordinary adhesives can sometimes be solved by silane coupling agents. For example aluminum and polyethylene, silicone rubber and metal, silicone rubber and plexiglass, they can get a satisfactory solution by selecting the corresponding silane coupling agents according to the chemical bond theory. For example, the use of vinyl triperoxide tert-butyl silane can bond polyethylene to the aluminum foil. The use of butadienyl triethoxysilane can make the peel strength between silicone rubber and metal reach 21.6-22.4KG/CM. Zhongtian provides a reasonable silane coupling agent price for customers.

The use of coupling agents with general adhesives or resins can not only improve the adhesive strength, but also increase the water resistance and durability of the adhesive force. For example, polyurethane and epoxy resin have high adhesion to many materials, but their adhesion durability and water resistance are not ideal. The performance in this area can be significantly improved after adding silane coupling agents.