Silicone composition

Abstract

The invention provides a silicone composition and a preparation method thereof. A hydrogen-containing polysiloxane reacts with an unsaturated polyether, and the obtained reaction product and a dimethylhydro-terminated vinyl polysiloxane undergo a hydrosilylation reaction and alkali treatment. The crosslinking viscosity is effectively controlled by the hydrogen-containing polysiloxane to form a dynamic crosslinked polymer having a spatial structure, and the addition of the unsaturated polyether improves the dispersing property of the silicone composition. The silicone composition can be used as a main body to prepare an organopolysiloxane defoamer, has a good defoaming performance in a high-temperature strong alkaline system, and has the advantages of good dispersibility, difficulty in agglomeration and precipitation, improvement of the foam suppression performance, and enhancement of the application performance in the later stage in the use process.

Description

technical field [0001] The invention relates to a crosslinkable organic silicon composition, which belongs to the technical field of fine chemical preparations. Background technique [0002] The paper industry is an important industry that is closely related to the development of the national economy. Although defoamers are used in a small amount in the paper industry, they play an extremely important role. In the pulping process of the paper industry, since the pulp contains a large amount of fatty acid soap, resin acid soap foaming substances, and cellulose foam stabilizing substances, pulp transportation is prone to produce a large amount of foam, which brings unnecessary The trouble and loss of alkaline slurry also bring health problems to production workers. Early paper mills used the method of "clear water pressure foam" to suppress the generation of foam, but the effect was not satisfactory. With the rise of the silicone industry and people's increasing attention to...

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Problems solved by technology

[0003] As early as 1968, research on the preparation of organopolysiloxane defoamers had already begun abroad. For example, in US3383327, polydimethylsiloxane was used as the main body to prepare defoamer compositions. However, due to its single structure, Foam suppression performance is poor

In later studies, US3455839 described a method for preparing a crosslinkable organopolysiloxane defoamer composition, and proposed for the first time the process of using vinyl polysiloxane to react with hydrogen-containing polysiloxane to improve The anti-foaming ability of the defoaming agent in the later stage is improved, but it still has some deficiencies in the defoaming performance; US4690713 points out that vinyl groups and phenyl groups have been introduced into polyorganosiloxane, and in the platinum catalyst catalyzed Cross-linking with hydrogen-containing polysiloxane under certain conditions to obtain a defoamer composition, but its antifoaming performance cannot fully meet the actual needs of production; US4639489 uses high-viscosity hydroxyl-terminated polysiloxane and polyethyl silicate The organopolysiloxane defoamer is prepared by reaction under alkali-catalyzed conditions, but due to the relatively high viscosity of the prepared organosilicon polymer, it does not have good defoaming performance; WO2013043487 states the use of organopolysiloxane containing hydroxyl Siloxane cross-links with organopolysiloxanes containing amino groups in the end chains, and prepares defoamer compositions. However, its cross-linking structure is relatively weak, and it is difficult to play a good inhibitory effect in strong alkali systems. Bubble action

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