阅读说明：本技术 一种室温硫化甲基硅橡胶的生产工艺 (Production process of room-temperature vulcanized methyl silicone rubber ) 是由 黄立忠 陶明海 李海成 黄金龙 童红梅 于 2019-11-29 设计创作，主要内容包括：本发明公开了一种室温硫化甲基硅橡胶的生产工艺,包括以下步骤：将100重量份二甲基环硅氧烷混合物抽入反应釜内后升温至90-100℃；加入5-10重量份活性白土作为催化剂,90-100℃保温聚合3-5小时,然后加入10-20重量份水保温1-2小时；170～230℃时抽低沸物,降温至90-100℃放料,冷却至室温,即得到无色透明状的室温硫化甲基硅橡胶。本发明使用少量的活性白土作为催化剂,可以吸附室温硫化甲基硅橡胶中的杂质,提高室温硫化甲基硅橡胶的透明度,且催化剂成本低廉,过滤之后可以重复利用。(The invention discloses a production process of room-temperature vulcanized methyl silicone rubber, which comprises the following steps: pumping 100 parts by weight of dimethyl cyclosiloxane mixture into a reaction kettle, and heating to 90-100 ℃; adding 5-10 parts by weight of activated clay as a catalyst, performing thermal insulation polymerization at 90-100 ℃ for 3-5 hours, and then adding 10-20 parts by weight of water, and performing thermal insulation for 1-2 hours; and (3) extracting low-boiling-point substances at 170-230 ℃, cooling to 90-100 ℃, discharging, and cooling to room temperature to obtain colorless and transparent room-temperature vulcanized methyl silicone rubber. The invention uses a small amount of activated clay as a catalyst, can adsorb impurities in the room-temperature vulcanized methyl silicone rubber, improves the transparency of the room-temperature vulcanized methyl silicone rubber, has low cost, and can be recycled after filtration.)

1. A production process of room-temperature vulcanized methyl silicone rubber is characterized by comprising the following steps:

(1) pumping 100 parts by weight of dimethyl cyclosiloxane mixture into a reaction kettle, and heating to 90-100 ℃;

(2) under the condition of stirring, adding 5-10 parts by weight of activated clay serving as a catalyst into a reaction kettle, fully and uniformly mixing, carrying out heat preservation polymerization at 90-100 ℃ for 3-5 hours, and then adding 10-20 parts by weight of water into the reaction kettle, and carrying out heat preservation for 1-2 hours;

(3) heating the reaction kettle at the speed of 25-30 ℃/h, starting a vacuum pump when the temperature of the reaction kettle rises to 170 ℃, maintaining the vacuum degree to be 0.85-0.1 MPa, pumping low-boiling-point substances, stopping heating when the temperature of the reaction kettle rises to 230 ℃, continuously pumping the low-boiling-point substances for 0.5-1 hour, and then cooling to 90-100 ℃ at the speed of 25-30 ℃/h;

(4) discharging the materials after the temperature of the reaction kettle is reduced to 90-100 ℃, and cooling to room temperature.

2. The process for producing a room temperature vulcanized methyl silicone rubber according to claim 1, characterized in that: in the dimethyl cyclosiloxane mixture, the weight percentage of D3, D4, D5 and D6 is more than or equal to 99.8 percent, and the weight percentage of D4 is more than or equal to 80 percent.

3. The process for producing a room temperature vulcanizing methyl silicone rubber according to claim 1 or 2, characterized in that: the water content of the dimethyl cyclosiloxane mixture is less than or equal to 0.1 wt%.

4. The process for producing a room temperature vulcanized methyl silicone rubber according to claim 1, characterized in that: the reaction kettle is a reaction kettle with an inner lining made of an anticorrosive material.

5. The process for producing a room temperature vulcanizing methyl silicone rubber according to claim 1 or 4, characterized in that: the reaction kettle is an enamel reaction kettle.

6. The process for producing a room temperature vulcanizing methyl silicone rubber according to claim 1 or 3, characterized in that: firstly introducing nitrogen into the reaction kettle to remove oxygen, and then pumping the dimethyl cyclosiloxane mixture into the reaction kettle.

7. The process for producing a room temperature vulcanized methyl silicone rubber according to claim 1, characterized in that: in the step (2), the addition amount of activated clay is 5 parts by weight.

8. The process for producing a room temperature vulcanized methyl silicone rubber according to claim 1, characterized in that: in the step (2), the polymerization temperature is 95 ℃ and the polymerization time is 3 hours.

9. The process for producing a room temperature vulcanized methyl silicone rubber according to claim 1, characterized in that: in the step (2), the addition amount of water is 10 parts by weight.

Technical Field

The invention relates to the field of silicone oil preparation, and in particular relates to a production process of room-temperature vulcanized methyl silicone rubber.

Background

Room temperature vulcanizing methyl silicone rubber, also known as 107 rubber, is a relatively low molecular weight, usually viscous fluid. The 107 glue can be cured with a cross-linking agent and a catalyst at room temperature, can keep elasticity for a long time within the temperature range of-60-220 ℃, has excellent electrical property and chemical stability, and can resist water, odor and weather aging. The product is widely used for building joint filling, insulation, shock resistance, moisture resistance and corrosion resistance of electronic components, moulding and demoulding of rubber and plastic products, leather lubricant and separant, is also a basic raw material of room temperature vulcanized silicone rubber, and can be used for fabric finishing and daily chemical industry with special specifications.

In the existing preparation method of room temperature vulcanized methyl silicone rubber: chinese patent CN 105131292A, a preparation method of low-viscosity 107 glue, discloses a method for polymerizing a linear body at 180 ℃ under the alkaline condition of carbonate, and the viscosity of the prepared product is less than 2000 mPa.s; chinese patent CN 105254893A, a Low viscosity 107 glue and a preparation method thereof, discloses a method for preparing a product with the viscosity of 2000-3000mPa.s by adopting DMC negative pressure polymerization under the conditions of 150 ℃ and potassium hydroxide alkalinity; in research on preparation process of low-difficulty 107 silicone rubber (2016, 38(5)) in Tangshan university academy of sciences, a 500-plus 2000mPa.s 107 rubber is prepared by polymerization of a linear body serving as a raw material under the catalysis of a strong-acid cation exchange resin; in a novel preparation process of low-difficulty 107 silicone rubber (Guangdong chemical industry, 2015, 38 (7): 64-65), hydrolysate is used as a raw material, and 500-3000mPa.s107 rubber is prepared by polymerization under the catalysis of strong-acid cation exchange resin at 80-120 ℃. The above prior art has the following problems: (1) carbonate is used as an alkaline catalyst, and because the amount of the carbonate is low in catalytic activity and large, the carbonate cannot be filtered thoroughly during product filtration, and partial salt is dissolved in the product, so that the transparency and the quality are influenced; (2) DMC high temperature catalysis is adopted, then water is added for degradation, and 107 glue with lower viscosity cannot be prepared due to factors such as reaction activation energy, equilibrium reaction and the like; (3) the low-viscosity 107 glue can be prepared by adopting hydrolysate or linear body under the condition of strong acid resin catalyst, and in the actual production process, the cost of the resin catalyst is higher and the resin catalyst needs to be treated by hazardous waste after being inactivated.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a production process of room-temperature vulcanized methyl silicone rubber, which solves the problems of high cost of a catalyst, low product transparency and the like in the prior art.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:

a production process of room-temperature vulcanized methyl silicone rubber comprises the following steps:

(1) pumping 100 parts by weight of dimethyl cyclosiloxane mixture into a reaction kettle, and heating to 90-100 ℃;

(2) under the condition of stirring, adding 5-10 parts by weight of activated clay serving as a catalyst into a reaction kettle, fully and uniformly mixing, carrying out heat preservation polymerization at 90-100 ℃ for 3-5 hours, and then adding 10-20 parts by weight of water into the reaction kettle, and carrying out heat preservation for 1-2 hours;

(3) heating the reaction kettle at the speed of 25-30 ℃/h, starting a vacuum pump when the temperature of the reaction kettle rises to 170 ℃, maintaining the vacuum degree to be 0.85-0.1 MPa, pumping low-boiling-point substances, stopping heating when the temperature of the reaction kettle rises to 230 ℃, continuously pumping the low-boiling-point substances for 0.5-1 hour, and then cooling to 90-100 ℃ at the speed of 25-30 ℃/h;

(4) discharging the materials after the temperature of the reaction kettle is reduced to 90-100 ℃, and cooling to room temperature.

On the basis of the technical scheme, in the dimethyl cyclosiloxane mixture, the weight percentage of D3+ D4+ D5+ D6 is more than or equal to 99.8 percent, and the weight percentage of D4 is more than or equal to 80 percent.

On the basis of the technical scheme, the water content of the dimethyl cyclosiloxane mixture is less than or equal to 0.1 wt%.

On the basis of the technical scheme, the reaction kettle is a reaction kettle with an inner lining made of an anticorrosive material.

On the basis of the technical scheme, the reaction kettle is an enamel reaction kettle.

On the basis of the technical scheme, firstly introducing nitrogen into the reaction kettle to remove oxygen, and then pumping the dimethyl cyclosiloxane mixture into the reaction kettle.

In addition to the above technical means, in the step (2), the amount of activated clay added is 5 parts by weight.

On the basis of the technical scheme, in the step (2), the polymerization temperature is 95 ℃, and the polymerization time is 3 hours.

On the basis of the above technical scheme, in the step (2), the addition amount of water is 10 parts by weight.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the invention uses a small amount of active clay (98 wt%) as a catalyst, can adsorb impurities in the room-temperature vulcanized methyl silicone rubber, improves the transparency of the room-temperature vulcanized methyl silicone rubber, has low cost of the catalyst, and can be recycled after filtration.

Detailed Description

The technical solution of the present invention will be described in further detail with reference to examples.

The reactors used in the following examples are all enamel reactors.