Low-viscosity hydroxyl-terminated vinyl methyl silicone oil and continuous preparation method thereof
阅读说明：本技术 低粘度羟基封端乙烯基甲基硅油及其连续化制备方法 (Low-viscosity hydroxyl-terminated vinyl methyl silicone oil and continuous preparation method thereof ) 是由 曲雪丽 刘彬 赵洁 曹鹤 李献起 张鹏硕 刘秋艳 周健 王东英 王占亮 王议 于 2019-09-26 设计创作，主要内容包括：本发明涉及一种低粘度羟基封端乙烯基甲基硅油及其连续化制备方法。将八甲基环四硅氧烷、四甲基四乙烯基环四硅氧烷和乙酸酐加入混合釜,搅拌混合均匀后,进入装有催化剂的高压固定床中进行开环聚合反应；将生成的链状的乙酰氧基封端硅氧烷加入到解析塔中复合盐水中进行水解,经过两级相分离器、两级水洗分离器,得到粗产物；水解后的水相经过蒸发器、结晶器,最后离心干燥得到副产物醋酸盐,其蒸馏水再利用,进入水洗分离器；水解得到粗产物,经过硅藻土和活性炭干燥吸附,最终得到羟基封端乙烯基甲基硅油。本发明与现有技术相比,本发明的有益效果是：促进开环聚合反应,省去了水洗酸的过程；羟基摩尔分数稳定；蒸馏水回收利用,产品纯度高。(The invention relates to low-viscosity hydroxyl-terminated vinyl methyl silicone oil and a continuous preparation method thereof. Adding octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane and acetic anhydride into a mixing kettle, stirring and mixing uniformly, and then entering a high-pressure fixed bed filled with a catalyst to perform ring-opening polymerization reaction; adding the generated chain-shaped acetoxyl terminated siloxane into composite brine in an analytical tower for hydrolysis, and obtaining a crude product through a two-stage phase separator and a two-stage water washing separator; the water phase after hydrolysis passes through an evaporator and a crystallizer, and is finally centrifugally dried to obtain a byproduct acetate, and the distilled water of the acetate is recycled and enters a water washing separator; hydrolyzing to obtain a crude product, and drying and adsorbing by using diatomite and active carbon to finally obtain the hydroxyl-terminated vinyl methyl silicone oil. Compared with the prior art, the invention has the beneficial effects that: the ring-opening polymerization reaction is promoted, and the process of washing acid with water is omitted; the hydroxyl mole fraction is stable; the distilled water is recycled, and the product purity is high.)
1. A low-viscosity hydroxyl-terminated vinyl methyl silicone oil and a continuous preparation method thereof are carried out according to the following steps:
1) performing ring-opening polymerization, namely adding octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane and acetic anhydride into a mixing kettle, stirring and mixing uniformly, and then entering a high-pressure fixed bed filled with a catalyst to perform ring-opening polymerization reaction;
2) hydrolysis separation, namely adding the generated chain acetoxyl terminated siloxane into composite brine in an analytical tower for hydrolysis, and obtaining a crude product through a two-stage phase separator and a two-stage water washing separator;
3) evaporating, concentrating and crystallizing, passing the hydrolyzed water phase through an evaporator and a crystallizer, and finally centrifugally drying to obtain a byproduct acetate, reusing distilled water of the acetate, and feeding the acetate into a water washing separator;
4) adsorbing, drying, purifying and hydrolyzing to obtain a crude product, and drying and adsorbing by using diatomite and active carbon to finally obtain the hydroxyl-terminated vinyl methyl silicone oil.
2. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: the molar ratio of the octamethylcyclotetrasiloxane, the tetramethyltetravinylcyclotetrasiloxane and the acetic anhydride in the step 1) is 0-5: 1, and the octamethylcyclotetrasiloxane and the tetramethyltetravinylcyclotetrasiloxane cannot be 0 at the same time.
3. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: the catalyst in the step 1) is strong acid sulfonic acid resin or a trifluoromethyl sulfonic acid type catalyst.
4. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: in the step 1), the reaction temperature is 100-120 ℃, the reaction pressure is 6-9 MPa, and the reaction residence time is 30-90 min.
5. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: step 2) the composite brine is NaHCO3With Na2CO3The method comprises the following steps of 1:1Is prepared from NaHCO3Has a mass concentration of 10-20% and Na2CO3The mass concentration of the composite salt water is 15-25%, and the volume ratio of the composite salt water to the acetoxysiloxane is 2-4: 1.
6. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: and 2) reacting in an analytical tower at the temperature of 65-85 ℃ for 2-4 h until the pH value is 9-11.
7. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: and 3) the hydrolyzed water phase adopts normal pressure evaporation concentration.
8. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: and 3) generating steam in the evaporation process to serve as a heat source for preheating the mixing kettle, recycling distilled water of the steam, and enabling the distilled water to enter the washing kettle.
9. The continuous production method of a hydroxyl-terminated vinylmethylsilicone oil according to claim 1, wherein: and 4) adopting an adsorption column filled with diatomite and activated carbon for adsorption and filtration, wherein the retention time is 60-90 min.
Technical Field
The invention relates to low-viscosity hydroxyl-terminated vinyl methyl silicone oil and a continuous preparation method thereof.
Background
The low-viscosity hydroxyl-terminated vinyl methyl silicone oil is hydroxyl-terminated polysiloxane with a branched chain containing vinyl, is used as a structure control agent to replace low-viscosity hydroxyl silicone oil in the silicone rubber preparation industry, and has better performance and better effect. The hydroxyl groups at two ends of the molecule and the active groups of the white carbon black play the role of a structure control agent; vinyl in the branched chain and vinyl of raw rubber are subjected to cross-linking reaction, and the low-viscosity hydroxyl terminated vinyl methyl silicone oil has the double functions of silicone rubber.
The low-viscosity hydroxyl-terminated vinyl methyl silicone oil is used as a functional auxiliary agent and added into the electric packaging adhesive with the bonding performance, so that the original bonding performance of the packaging adhesive can be greatly improved, and the low-viscosity hydroxyl-terminated vinyl methyl silicone oil plays an extremely important role in improving the mechanical performance.
Disclosure of Invention
The invention relates to low-viscosity hydroxyl-terminated vinyl methyl silicone oil and a continuous preparation method thereof.
The invention adopts the following technical scheme:
a low-viscosity hydroxyl-terminated vinyl methyl silicone oil and a continuous preparation method thereof are carried out according to the following steps:
1) performing ring-opening polymerization, namely adding octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane and acetic anhydride into a mixing kettle, stirring and mixing uniformly, and then entering a high-pressure fixed bed filled with a catalyst to perform ring-opening polymerization reaction;
2) hydrolysis separation, namely adding the generated chain acetoxyl terminated siloxane into composite brine for hydrolysis, and obtaining a crude product through a two-stage phase separator and a two-stage water washing separator;
3) evaporating, concentrating and crystallizing, passing the hydrolyzed water phase through an evaporator and a crystallizer, and finally centrifugally drying to obtain a byproduct acetate, reusing distilled water of the acetate, and feeding the acetate into a water washing separator;
4) adsorbing, drying, purifying and hydrolyzing to obtain a crude product, and drying and adsorbing by using diatomite and active carbon to finally obtain the hydroxyl-terminated vinyl methyl silicone oil.
Compared with the prior art, the invention adopting the technical scheme has the beneficial effects that:
1) the catalyst promotes the ring-opening polymerization reaction, omits the process of washing acid, avoids the condensation reaction of hydroxyl and acetoxyl formed in the early stage, and has stable product; the catalyst has high catalytic efficiency, can be repeatedly used and is suitable for continuous production.
2) With complex brine (NaHCO)3And Na2CO3Brine) to avoid further acetoxy and hydroxyl groupsThe condensation makes the hydrolysis reaction more complete and the mole fraction of the hydroxyl group is stable.
3) Evaporating, concentrating and crystallizing the hydrolyzed water phase to obtain a sodium acetate product, using steam as a heat source for preheating the mixing kettle, recycling distilled water of the sodium acetate product, and feeding the distilled water into a washing kettle; realizes cyclic utilization, has no pollutant discharge and is green and environment-friendly.
4) After passing through an adsorption column mixed by diatomite and active carbon, the product has high purity, low impurity ion content and good storage stability.
The preferred scheme of the invention is as follows:
the molar ratio of the octamethylcyclotetrasiloxane, the tetramethyltetravinylcyclotetrasiloxane and the acetic anhydride in the step 1) is 0-5: 1, and the octamethylcyclotetrasiloxane and the tetramethyltetravinylcyclotetrasiloxane cannot be 0 at the same time.
The catalyst in the step 1) is strong acid sulfonic acid resin or a trifluoromethyl sulfonic acid type catalyst.
In the step 1), the reaction temperature is 100-120 ℃, the reaction pressure is 6-9 MPa, and the reaction residence time is 30-90 min.
Step 2) the composite brine is NaHCO3With Na2CO3The method comprises the following steps of 1:1, NaHCO3Has a mass concentration of 10-20% and Na2CO3The mass concentration of the composite salt water is 15-25%, and the volume ratio of the composite salt water to the acetoxysiloxane is 2-4: 1.
And 2) reacting in a hydrolysis kettle at 65-85 ℃ for 2-4 h, wherein the pH value is 9-11.
And 3) the hydrolyzed water phase adopts normal pressure evaporation concentration.
And 3) generating steam in the evaporation process to serve as a heat source for preheating the mixing kettle, recycling distilled water of the steam, and enabling the distilled water to enter the washing kettle.
And 4) adopting an adsorption column filled with diatomite and activated carbon for adsorption and filtration, wherein the retention time is 60-90 min.
Drawings
FIG. 1 is a process flow diagram of the present invention.
In the figure: mixing kettle 1, high-pressure fixed bed 2, dispersion film type analytical tower 3, phase separator 1#4, phase separator 2#5, water washing kettle and separator 1#6, water washing kettle and separator 2#7, adsorption column 8, composite brine preparation kettle 9, evaporation crystallizer 10, centrifuge 11, feed inlet 12, acetoxy siloxane outlet 13, water washing liquid outlet 14, NaHCO3、Na2CO3A feed inlet 15, a silicone oil outlet 16, a hydrolyzed water phase outlet 17, a steam condensate inlet 18, a distilled water inlet 19 and a purified water inlet 20; and a sodium acetate salt outlet 21.
Detailed Description
To further illustrate the present invention, reference is made to the following examples:
the invention is further illustrated, but not limited, by the following process flow and examples in connection with fig. 1.