74results about How to "High capping rate" patented technology

The present invention provides a hydrophilic silicone which has a predetermined number of silicon atoms and a high purity and is suitable for producing an ophthalmic device and a process for preparing the same.The silicone compound is represented by formula (1) with a purity of 95% by weight or higher,wherein m is one value out of the integers of from 3 to 10, n is one value out of the integers of from 1 to 10, R1 is one out of alkyl groups having 1 to 4 carbon atoms, and R2 is one out of a hydrogen atom and a methyl group.

The invention discloses a preparation method of an alkoxy-terminated polysiloxane polymer. According to the method, by adopting organic amine salt as a catalyst for a reaction, the terminating rate of alpha,omega-dihydroxy polydimethylsiloxane is effectively increased and the catalyst and excessive terminating agent can be reacted to obtain amide substances which are harmless to the stability of a product so that the subsequent processing is not needed and the reaction flow is simplified.

The invention belongs to the field of modified silicone oil, specifically relates to a preparation method of alkoxy end capping silicone oil, and aims at solving the technical problems of the existing preparation that the process is complex because of starting from chlorosilane monomer, hydrogen chloride produced by hydrolyzing is difficult to remove, and therefore, the storage stability of a product is poor. The preparation method of the alkoxy end capping silicone oil comprises the following steps: adding a catalyst to high-viscosity-end hydroxyl polydimethylsiloxane and alkoxy silane under the protection of nitrogen, heating to be 80 to 130 DEG C, and reacting for 1 to 6 hours; b, neutralizing to be neutral after the reaction is done; c, filtering to obtain the filtrate that is the crude alkoxy end capping silicone oil product; d, distilling the crude product under a temperature of 120 to 170 DEG C and at a pressure of -0.06 to -0.09Mpa to obtain the alkoxy end capping silicone oil. According to the preparation method of the alkoxy end capping silicone oil, the reaction line is simple, the alkoxy end capping silicone oil is high in stability and high in end capping rate, and a new method is provided to the preparation of the alkoxy end capping silicone oil.

The invention belongs to the field of organic silicon polymers and in particular relates to a preparation method of alkoxy-terminated polydimethylsiloxane. Compared with an existing alkoxy terminationmethod, the preparation method of the alkoxy-terminated polydimethylsiloxane, provided by the invention, has the following technical effects that in step (1), the initial temperature (35 to 85 DEG C)is relatively low, reaction conditions are moderate and pressurizing or decompression operation is not needed; the total reaction time of the provided preparation method is less than 3h and the operation of all steps are simple and moderate to operate, so that safety production is facilitated, and efficient production of an alkoxy-terminated polydimethylsiloxane product is also realized at the same time; one of dimethylamine, diethylamine, dipropylamine, methyl ethylamine and pyrrolidine is used as a catalyst; the termination rate of the prepared alkoxy-terminated polydimethylsiloxane is high; the catalyst can be recycled and repeatedly utilized through a decompression distillation and rectification manner.