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CN-119799003-B - Preparation method and application of precipitated liquid silicone rubber base sizing material for high-performance keys

CN119799003BCN 119799003 BCN119799003 BCN 119799003BCN-119799003-B

Abstract

The invention discloses a preparation method and application of a precipitated liquid silicone rubber base sizing material for high-performance keys, and belongs to the field of preparation of precipitated silicone rubber. Mixing and kneading vinyl-terminated polydimethylsiloxane, dihydric alcohol and a release agent to obtain a mixture, putting the vinyl-terminated polydimethylsiloxane, the mixture, high-hydroxyl-value hydroxyl silicone oil and precipitated white carbon black into a closed kneader, starting kneading and heating to 80-120 ℃, heating to 130-180 ℃ after the sizing material is banburying and agglomerating, kneading at constant temperature, vacuum kneading, cooling and discharging to obtain the precipitated liquid silicone rubber base sizing material with fluidity and semitransparent appearance. The process is used for preparing the precipitated liquid silicone rubber base sizing material by a two-step method, so that the yellowing problem of the base sizing material is avoided, the semitransparent base sizing material can be stably prepared, the white carbon black in the base sizing material has better dispersing effect, the structuring degree is low after the base sizing material is stored for 6 months, the viscosity change rate is small, and the mechanical property after vulcanization is excellent, so that the process can be applied to the field of keys.

Inventors

  • ZHU ZONGWEI
  • ZHANG KAIQIANG
  • WANG TAO
  • LU YI
  • ZHAO LIUXI
  • WANG XIAOXIANG
  • ZHANG GUANGRONG
  • XIE XIAOFENG
  • WANG FAN

Assignees

  • 湖北兴瑞硅材料有限公司

Dates

Publication Date
20260508
Application Date
20241203

Claims (8)

  1. 1. The preparation method of the precipitated liquid silicone rubber base sizing material for the high-performance keys is characterized by comprising the following steps of: (1) Mixing vinyl-terminated polydimethylsiloxane, dihydric alcohol and zinc stearate, and kneading for 20-120 min at 80-180 ℃ to obtain a mixture, wherein the dihydric alcohol is ethylene glycol, propylene glycol, butanediol or a mixture thereof, and the mass ratio of the vinyl-terminated polydimethylsiloxane to the dihydric alcohol to the zinc stearate is 1:0.01-0.5:0.1-2; (2) Sequentially heating and kneading vinyl-terminated polydimethylsiloxane, a mixture, high-hydroxyl-value hydroxyl silicone oil and precipitated white carbon black, cooling and discharging after vacuum kneading to obtain the precipitated liquid silicone rubber base sizing material, wherein the high-hydroxyl-value hydroxyl silicone oil is micromolecular hydroxyl silicone oil with hydroxyl content of more than 1.0%, viscosity of 10-300 mPa.s, and the mass ratio of the vinyl-terminated polydimethylsiloxane, the mixture, the high-hydroxyl-value hydroxyl silicone oil and the precipitated white carbon black is 40-80:0.05-1:1-10:10-40.
  2. 2. The preparation method of the precipitated liquid silicone rubber base sizing material for high-performance keys, which is disclosed in claim 1, is characterized in that the viscosity of the vinyl-terminated polydimethylsiloxane in the step (1) is 100-100000 mPa.s, the vinyl content is 0.07-1.06 wt% and the volatile content is less than or equal to 1.0%.
  3. 3. The method for preparing a precipitated liquid silicone rubber base stock for high-performance keys according to claim 1, wherein the vinyl-terminated polydimethylsiloxane in the step (1) is one vinyl-terminated polydimethylsiloxane or a combination of two or more vinyl-terminated polydimethylsiloxanes having a viscosity of 100 to 100000 mPa.s.
  4. 4. The preparation method of the precipitated liquid silicone rubber base sizing material for the high-performance keys, which is disclosed in claim 1, is characterized in that in the step (2), the precipitated liquid silicone rubber base sizing material is kneaded for 1-6 hours at 130-180 ℃ and then kneaded for 0.5-2 hours at a vacuum degree of minus 0.08-minus 0.1 MPa.
  5. 5. The method for preparing the precipitated liquid silicone rubber base sizing material for the high-performance keys, which is disclosed in claim 1, is characterized in that the mass ratio of vinyl-terminated polydimethylsiloxane, dihydric alcohol and zinc stearate is 1:0.02-0.3:0.5-1.5.
  6. 6. The preparation method of the precipitated liquid silicone rubber base sizing material for the high-performance keys, which is disclosed in claim 1, is characterized in that the precipitated white carbon black in the step (2) is hydrophilic, the specific surface area is 100-300 m 2 /g, and the precipitated white carbon black is added for 4-10 times in 30-120 min.
  7. 7. A silicone rubber sheet characterized in that a precipitated liquid silicone rubber base stock for high-performance keys is prepared according to the preparation method of any one of claims 1 to 6.
  8. 8. The method for producing a silicone rubber sheet according to claim 7, wherein, Preparing an A adhesive, namely adding a Karst platinum catalyst into the precipitated liquid silicone rubber base adhesive for the high-performance keys prepared by the method of any one of claims 1-6, and uniformly mixing to obtain the A adhesive; The preparation of the adhesive B, namely adding an acetylene cyclohexanol inhibitor and hydrogen-containing silicone oil into the precipitated liquid silicone rubber base adhesive for the high-performance keys, which is prepared by the method according to any one of claims 1-6, and uniformly mixing and stirring to obtain the adhesive B; and uniformly mixing the adhesive A and the adhesive B, then carrying out vacuum defoaming, and vulcanizing at 120-130 ℃ to obtain the silicone rubber sheet.

Description

Preparation method and application of precipitated liquid silicone rubber base sizing material for high-performance keys Technical Field The invention relates to the field of precipitated silicone rubber, in particular to a preparation method and application of a precipitated liquid silicone rubber base sizing material for high-performance keys. Background The addition type Liquid Silicone Rubber (LSR) is a liquid silicone rubber which takes polysiloxane containing vinyl as a base polymer and takes oligosiloxane containing hydrogen bonds as a vulcanization crosslinking agent, and can form an elastomer with a network result through addition reaction under the action of a platinum catalyst. LSR is nontoxic and odorless, has excellent weather resistance and chemical inertness, and has wide application field and broad market prospect. With the popularization and intelligent development of electronic products, the market scale of silicone rubber keys is continuously enlarged, and the application fields are wide, including the fields of household appliances, automobile industry, electronic communication fields and the like, such as remote controller keys, automobile center console and steering wheel keys, telephone keys and the like. Compared with other material keys, the silicon rubber key has the advantages of good elasticity, high and low temperature resistance, strong weather resistance, good touch feeling and the like. Chinese patent publication No. 105968819a discloses a key liquid silicone rubber with ultra-high striking life, good mechanical properties and high striking resistance life. However, the key liquid silicone rubber prepared by the patent is prepared from raw materials such as fumed silica, hexamethyldisilazane, vinyl MQ silicone resin and the like, and has relatively high price and high cost, and the mechanical properties of the prepared silicone rubber do not reach excellent properties. Therefore, a preparation method and application of a precipitated liquid silicone rubber base sizing material for high-performance keys are provided. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a preparation method and application of a precipitated liquid silicone rubber base sizing material for high-performance keys. The preparation process is a two-step method, so that the yellowing problem of the basic sizing material is avoided, the semitransparent basic sizing material can be stably prepared, the dispersion effect of the white carbon black in the basic sizing material is better, the structuring degree is low after the basic sizing material is stored for 6 months, the viscosity change rate is low, and the mechanical property after vulcanization is high. In order to achieve the above object, the present invention provides the following technical solutions: a preparation method of a precipitated liquid silicone rubber base sizing material for high-performance keys comprises the following steps: (1) Adding vinyl-terminated polydimethylsiloxane, dihydric alcohol and a release agent into a closed kneader according to a certain proportion, starting kneading, heating to 80-180 ℃, and kneading for 20-120 min at constant temperature to prepare a mixture. (2) Adding vinyl-terminated polydimethylsiloxane, a mixture, high-hydroxyl-value hydroxyl silicone oil and precipitated white carbon black into a closed kneader, starting kneading and heating to 80-120 ℃, heating to 130-180 ℃ after the sizing material is banburying and agglomerating, kneading at constant temperature for 1-6 h, and continuously vacuumizing and kneading at the temperature for 0.5-2 h, wherein the vacuum degree is less than-0.08 MPa. (3) Cooling and discharging to obtain the precipitated liquid silicone rubber base sizing material for the high-performance keys. The viscosity of the vinyl-terminated polydimethylsiloxane is 100-100000 mPa.s (25 ℃), the vinyl content is 0.07-1.06 wt% and the volatile matter is less than or equal to 1.0% (150 ℃ for 3 h). The vinyl-terminated polydimethylsiloxane is one vinyl-terminated polydimethylsiloxane or a combination of two or more vinyl-terminated polydimethylsiloxanes with the viscosity of 100-100000 mPa.s. The dihydric alcohol is cosolvent, and is ethylene glycol, propylene glycol, butanediol or their mixture. The release agent is zinc stearate. The mass ratio of the vinyl-terminated polydimethylsiloxane to the dihydric alcohol to the release agent is 1:0.01-0.5:0.1-2, and preferably 1:0.02-0.3:0.5-1.5. The Gao Qiang-value hydroxyl silicone oil has a hydroxyl group content of more than 1.0%, a viscosity of 10-300 mPas (25 ℃), more preferably a hydroxyl group content of more than 5.0%, more preferably a hydroxyl group content of more than 8.0%, more preferably a hydroxyl group content of more than 10.0%, and more preferably a hydroxyl group content of more than 12.0%. The precipitated silica is hydrophilic, the specific surface area is 100-300 m 2/g, and the preci