Microcapsule catalyst, preparation method and applications thereof

Abstract

The invention relates to a microcapsule catalyst, a preparation method and applications thereof. The microcapsule catalyst comprises a heated and melted organic silicon wax matrix and a hydrosilylation catalyst embedded in the organic silicon wax matrix. The preparation method comprises the following steps: mixing organic silicon wax and an organic solvent, heating to melt the organic silicon wax,and adding a hydrosilylation catalyst to obtain a mixed solution; providing a dispersion solution comprising a dispersing agent and water, adding the mixed solution into the dispersion solution, dispersing the mixed solution into the dispersion solution, and cooling to obtain a microcapsule catalyst suspension liquid; and separating the microcapsule catalyst suspension liquid to obtain the microcapsule catalyst. The microcapsule catalyst can be uniformly dispersed in a silicone rubber composition, and is heated and melted to release the catalyst so as to rapidly catalyze the silicone rubber composition to perform a hydrosilation reaction, so that the utilization rate of the catalyst is high.

Description

technical field [0001] The invention relates to the field of catalysts, in particular to microcapsule catalysts and their preparation methods and applications. Background technique [0002] At present, liquid silicone rubber is generally prepared into silicone rubber by hydrosilylation under the action of platinum, rhodium, palladium and other precious metal catalysts. However, the noble metal catalyst used in the hydrosilylation reaction has very high catalytic activity and can catalyze the hydrosilylation reaction at room temperature. Therefore, it is generally necessary to add a curing retarder during the reaction to make it stable at room temperature, and the reaction can only occur after the temperature is raised. However, commonly used curing retardants are electron-deficient olefins, such as acetylenic alcohols, dimethyl maleate, dimethyl fumarate, etc. These curing retardants have weak coordination ability with noble metal catalysts, so they can only Delaying the r...

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Problems solved by technology

[0004] However, most of the current microcapsule catalysts use thermoplastic polymers as wall materials. Although the microcapsules soften and the catalyst can be released when the temperature rises above the glass transition temperature of the thermoplastic polymers, for systems that require rapid curing (such as Injection molding of liquid silicone rubber), the catalyst diffuses slowly in the silicone with high viscosity, resulting in slow curing

Secondly, the compatibility between thermoplastic polymer and silicone is poor, the catalyst can only be dispersed by diffusion, and the diffused catalyst quickly catalyzes the hydrosilylation reaction to obtain silicone rubber, which makes the surroundings of the microcapsules solidify, the catalyst cannot continue to diffuse, and the utilization rate of the catalyst is low

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