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

Abstract

The invention discloses a preparation method and application of a precipitated liquid silicone rubber base rubber material for a high-performance key, and belongs to the field of preparation of precipitated silicone rubber. The preparation method comprises the following steps: mixing vinyl-terminated polydimethylsiloxane, dihydric alcohol and a release agent, and kneading to obtain a mixture; putting vinyl-terminated polydimethylsiloxane, the mixture, high-hydroxyl-value hydroxyl silicone oil and precipitated white carbon black into a closed kneading machine, starting kneading, heating to 80-120 DEG C, heating to 130-180 DEG C after the sizing material is internally mixed into a cluster, kneading at constant temperature, and kneading in vacuum; the prepared precipitated liquid silicone rubber basic rubber material has fluidity and is semitransparent in appearance. According to the process, the precipitated liquid silicone rubber basic rubber material is prepared by a two-step method, so that the yellowing problem of the basic rubber material is avoided, and the semitransparent basic rubber material can be stably prepared; the white carbon black in the basic sizing material has a better dispersing effect, and after the basic sizing material is stored for 6 months, the structuring degree is low, and the viscosity change rate is small; the vulcanized rubber has excellent mechanical properties and can be applied to the field of keys.

Description

Technical Field

[0001] The invention relates to the field of precipitated silicone rubber, and in particular to a preparation method and application of a precipitated liquid silicone rubber base compound for high-performance buttons. Background Art

[0002] Addition liquid silicone rubber (LSR) is a kind of liquid silicone rubber with a network elastic body formed by addition reaction with vinyl-containing polysiloxane as the base polymer and hydrogen-bonded oligosiloxane as the vulcanization crosslinking agent under the action of platinum catalyst. LSR is non-toxic and odorless, has excellent weather resistance and chemical inertness, has a wide range of applications, and has broad market prospects.

[0003] With the popularization and intelligent development of electronic products, the market size of silicone rubber buttons continues to expand, and its application fields are wide, including home appliances, automotive industry, electronic communications, etc., such as remote control buttons, car center console and steering wheel buttons, telephone buttons, etc. Compared with buttons made of other materials, silicone rubber buttons have the advantages of good elasticity, high and low temperature resistance, strong weather resistance, and good touch.

[0004] The Chinese patent with publication number 105968819A discloses a keypad liquid silicone rubber with ultra-high impact life, good mechanical properties, and high impact resistance life. However, the raw materials used in the keypad liquid silicone rubber prepared in this patent are fumed silica, hexamethyldisilazane, vinyl MQ silicone resin, etc., which are relatively expensive and costly, and the mechanical properties of the prepared silicone rubber do not fully achieve excellent performance.

[0005] Therefore, a preparation method and application of a precipitated liquid silicone rubber base compound for high-performance buttons are proposed. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a preparation method and application of a precipitated liquid silicone rubber base material for high-performance buttons. The preparation process described in the present invention is a "two-step method", which avoids the yellowing problem of the base material and can stably prepare a translucent base material; and the dispersion effect of white carbon black in the base material is better. After storage for 6 months, the degree of structuring is low and the viscosity change rate is small; the mechanical properties are high after vulcanization. In order to achieve the above purpose, the present invention provides the following technical solutions:

[0007] A method for preparing a precipitated liquid silicone rubber base compound for high-performance buttons comprises the following steps:

[0008] (1) Vinyl-terminated polydimethylsiloxane, diol and release agent are added into a closed kneader according to a certain ratio, kneading is started and the temperature is increased to 80-180° C., and kneading is carried out at a constant temperature for 20-120 minutes to obtain a mixture.

[0009] (2): Put the vinyl-terminated polydimethylsiloxane, the mixture, the high-hydroxyl-value hydroxy silicone oil and the precipitated silica into a closed kneading machine, start kneading and raise the temperature to 80-120°C. After the rubber material is kneaded into a mass, raise the temperature to 130-180°C, knead at a constant temperature for 1-6 hours, and continue to knead at this temperature for 0.5-2 hours, with the vacuum degree less than -0.08MPa.

[0010] (3): Cooling and discharging the material to obtain a precipitated liquid silicone rubber base compound for high-performance buttons.

[0011] The vinyl-terminated polydimethylsiloxane has a viscosity of 100 to 100,000 mPa·s (25° C.), a vinyl content of 0.07 to 1.06 wt %, and a volatile content of ≤1.0% (150° C.*3h).

[0012] The vinyl-terminated polydimethylsiloxane is one vinyl-terminated polydimethylsiloxane having a viscosity of 100 to 100,000 mPa·s or a combination of two or more vinyl-terminated polydimethylsiloxanes.

[0013] The diol is a cosolvent, which is ethylene glycol, propylene glycol, butylene glycol or a mixture thereof.

[0014] The release agent is zinc stearate.

[0015] The mass ratio of the vinyl-terminated polydimethylsiloxane, diol and release agent is 1:0.01-0.5:0.1-2, preferably 1:0.02-0.3:0.5-1.5.

[0016] The high hydroxyl value hydroxy silicone oil has a hydroxyl content greater than 1.0% and a viscosity of 10 to 300 mPa·s (25°C), more preferably a hydroxyl content greater than 5.0%, more preferably a hydroxyl content greater than 8.0%, more preferably a hydroxyl content greater than 10.0%, and more preferably a hydroxyl content greater than 12.0%.

[0017] The precipitated silica is hydrophilic and has a specific surface area of ​​100 to 300 m 2 / g, add in 4 to 10 times within 30 to 120 minutes to ensure full combination with vinyl-terminated polydimethylsiloxane, mixture and high hydroxyl value hydroxy silicone oil.

[0018] The mass ratio of the vinyl-terminated polydimethylsiloxane, the mixture, the high-hydroxyl-value hydroxy silicone oil and the precipitated white carbon black is 40-80:0.05-1:1-10:10-40.

[0019] The precipitated liquid silicone rubber base rubber prepared by the process method of the present invention has fluidity and a translucent appearance, and the white carbon black dispersion effect in the base rubber is better. After being stored for 6 months, the structural degree is low and the viscosity change rate is small; and the mechanical properties are high after vulcanization.

[0020] Another technical solution of the present invention is to provide a silicone rubber sheet, and the preparation method is used to prepare a precipitated liquid silicone rubber base compound for high-performance keys.

[0021] The method for preparing the silicone rubber sheet comprises the following steps:

[0022] Preparation of glue A: Adding Custer platinum catalyst to the high-performance precipitated liquid silicone rubber base rubber for buttons prepared by the method, and mixing evenly to obtain glue A;

[0023] Preparation of B glue: adding acetylene cyclohexanol inhibitor and hydrogen-containing silicone oil to the high-performance precipitated liquid silicone rubber base rubber for keys prepared by the method, mixing and stirring to obtain B glue;

[0024] After the A and B glues are mixed evenly, vacuum degassing is performed and the silicone rubber sheet is obtained by vulcanizing at 120-130° C. for 3-10 minutes.

[0025] The thickness of the obtained silicone rubber sheet is 1 to 6 mm.

[0026] The beneficial effects of the present invention are as follows: the present invention provides a precipitated liquid silicone rubber base rubber for high-performance buttons, and specifically discloses a preparation method and application of a precipitated liquid silicone rubber base rubber for high-performance buttons. The release agent used in the present invention is zinc stearate, which has good demoulding effect and low cost, and is widely used in the field of silicone rubber. However, the addition of zinc stearate release agent has a negative impact on the performance and appearance of silicone rubber. Therefore, in the preparation process of the silicone rubber base rubber, if the dosage and the processing temperature and time are not well controlled, the rubber is very likely to turn yellow and directly affect the performance. The present invention provides a new basic rubber preparation process method, which is prepared in a "two-step method". First, zinc stearate and diol are dissolved in a vinyl-terminated polydimethylsiloxane at a certain temperature in a certain proportion. At this time, the powdered zinc stearate dissolves to form a white paste or a white paste to obtain a mixture, which is then put into the basic rubber preparation process. Although this method requires more experimental operations, the mixed paste can be used several times after being prepared once, and does not need to be prepared and used immediately. The prepared basic rubber has excellent performance, avoids the yellowing problem of the basic rubber, and can stably prepare a translucent basic rubber; and the white carbon black in the basic rubber has a better dispersion effect. After storage for 6 months, the degree of structuring is low and the viscosity change rate is small; the mechanical properties after vulcanization are excellent. The present invention effectively improves the performance of precipitated liquid silicone rubber, reduces production costs, is suitable for the field of buttons, and can replace most of the application fields of gas-phase liquid silicone rubber, and has good market value and prospects.

[0027] Another technical solution of the present invention is to use the prepared basic rubber material for the preparation of precipitated silicone rubber AB rubber, and then mix and vulcanize at a mass ratio of 1:1 to obtain precipitated liquid silicone rubber for keys. The precipitated liquid silicone rubber obtained after vulcanization has excellent performance, and the tensile performance can reach above 5MPa, more preferably above 6MPa, and more preferably above 7MPa; the tear strength can reach above 16kN / m, more preferably above 18kN / m, the tear strength can reach above 20kN / m, and the tear strength can reach above 21kN / m.

[0028] Through the above technical solution, the present invention has the following technical effects:

[0029] The preparation process of the present invention is a "two-step method", which avoids the yellowing problem of the base rubber and can stably prepare a translucent base rubber; the white carbon black dispersion effect in the base rubber is better, and after storage for 6 months, the degree of structuring is low and the viscosity change rate is small; the precipitated liquid silicone rubber after vulcanization has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the appearance of the basic rubber material prepared in Example 1.

[0031] Figure 2 This is the appearance of the basic rubber material prepared in Comparative Example 1.

[0032] Figure 3 This is the appearance of the basic rubber material prepared in Comparative Example 2. DETAILED DESCRIPTION

[0033] The present invention is further explained below with reference to the examples, but the examples do not limit the present invention in any form.

[0034] Example 1

[0035] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 130° C., and the kneading was continued at a constant temperature for 90 minutes to obtain a mixture.

[0036] (2) 2500 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 60 g of the mixture, and 240 g of hydroxy silicone oil with a hydroxyl value of 5% are added to a closed kneader, and 1200 g of precipitated silica is added to the kneader in 5 portions over 60 minutes. The kneading is started and the temperature is raised to 90°C. After the rubber material is kneaded into a mass, the temperature is raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading is continued at this temperature for 1 hour, and the vacuum degree is less than -0.08 MPa.

[0037] (3): Cool the material and obtain the precipitated liquid silicone rubber base compound.

[0038] Example 2

[0039] (1) 800 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 80 g of ethylene glycol, and 800 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 130° C., and the mixture was kneaded at a constant temperature for 90 minutes to obtain a mixture.

[0040] (2) 2520 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 40 g of the mixture, and 240 g of hydroxy silicone oil with a hydroxyl value of 5% are added to a closed kneader. 1200 g of precipitated silica is added to the kneader in 5 portions over 60 minutes. The kneading is started and the temperature is raised to 90°C. After the rubber material is kneaded into a mass, the temperature is raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading is continued at this temperature for 1 hour, and the vacuum degree is less than -0.08 MPa.

[0041] (3): Cool the material and obtain the precipitated liquid silicone rubber base compound.

[0042] Example 3

[0043] (1) 600 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 90 g of ethylene glycol, and 900 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 140° C., and the mixture was kneaded at a constant temperature for 90 minutes to obtain a mixture.

[0044] (2) 2525 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 35 g of the mixture, and 240 g of hydroxy silicone oil with a hydroxyl value of 5% are added to a closed kneader. 1200 g of precipitated silica is added to the kneader in 5 portions over 60 minutes. The kneading is started and the temperature is raised to 90°C. After the rubber material is kneaded into a mass, the temperature is raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading is continued at this temperature for 1 hour, and the vacuum degree is less than -0.08 MPa.

[0045] (3): Cool the material and obtain the precipitated liquid silicone rubber base compound.

[0046] Example 4

[0047] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 25 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading was started, the temperature was raised to 130° C., and the kneading was performed at a constant temperature for 90 minutes to obtain a mixture.

[0048] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0049] Example 5

[0050] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 75 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 130° C., and the kneading was continued at a constant temperature for 90 minutes to obtain a mixture.

[0051] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0052] Example 6

[0053] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 125 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 130° C., and the kneading was continued at a constant temperature for 90 minutes to obtain a mixture.

[0054] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0055] Example 7

[0056] (1) 1000 g of 20000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 130° C., and the mixture was kneaded at a constant temperature for 90 minutes to obtain a mixture.

[0057] (2) 2500 g of 20000 mPa·s vinyl-terminated polydimethylsiloxane, 60 g of the mixture, and 240 g of hydroxy silicone oil with a hydroxyl value of 5% are added to a closed kneader, and 1200 g of precipitated silica is added to the kneader in 5 portions over 60 minutes. The kneading is started and the temperature is raised to 90°C. After the rubber material is kneaded into a mass, the temperature is raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading is continued at this temperature for 1 hour, and the vacuum degree is less than -0.08 MPa.

[0058] (3): Cool the material and obtain the precipitated liquid silicone rubber base compound.

[0059] Example 8

[0060] (1) 1000 g of 60000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of propylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 130° C., and the mixture was kneaded at a constant temperature for 90 minutes to obtain a mixture.

[0061] (2) 2500 g of 60000 mPa·s vinyl-terminated polydimethylsiloxane, 60 g of the mixture, and 240 g of hydroxy silicone oil with a hydroxyl value of 5% are added to a closed kneader. 1200 g of precipitated silica is added to the kneader in 5 portions over 60 minutes. The kneading is started and the temperature is raised to 90°C. After the rubber material is kneaded into a mass, the temperature is raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading is continued at this temperature for 1 hour, and the vacuum degree is less than -0.08 MPa.

[0062] (3): Cool the material and obtain the precipitated liquid silicone rubber base compound.

[0063] Example 9

[0064] (1) 1000 g of 100000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of butanediol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 130° C., and the mixture was kneaded at a constant temperature for 90 min to obtain a mixture.

[0065] (2) 2500 g of 100000 mPa·s vinyl-terminated polydimethylsiloxane, 60 g of the mixture, and 240 g of hydroxy silicone oil with a hydroxyl value of 5% are added to a closed kneader, and 1200 g of precipitated silica is added to the kneader in 5 portions over 60 minutes. The kneading is started and the temperature is raised to 90°C. After the rubber material is kneaded into a mass, the temperature is raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading is continued at this temperature for 1 hour, and the vacuum degree is less than -0.08 MPa.

[0066] (3): Cool the material and obtain the precipitated liquid silicone rubber base compound.

[0067] Example 10

[0068] 2500g of 10000mPa·s vinyl-terminated polydimethylsiloxane, 60g of the mixture prepared in Example 1, and 240g of hydroxy silicone oil with a hydroxyl value of 8% were added to a closed kneader, and 1200g of precipitated silica was added to the kneader in 5 portions over 60 minutes. The kneading was started and the temperature was raised to 90°C. After the rubber material was kneaded into a mass, the temperature was raised to 150°C. After constant temperature kneading for 2h, vacuum kneading was continued at this temperature for 1h, and the vacuum degree was less than -0.08MPa. The material was cooled and discharged to obtain a precipitated liquid silicone rubber base rubber material.

[0069] Embodiment 11

[0070] 2500g of 10000mPa·s vinyl-terminated polydimethylsiloxane, 60g of the mixture prepared in Example 1, and 240g of hydroxy silicone oil with a hydroxyl value of 10% were added to a closed kneader, and 1200g of precipitated silica was added to the kneader in 5 portions over 60 minutes. The kneading was started and the temperature was raised to 90°C. After the rubber material was kneaded into a mass, the temperature was raised to 150°C. After constant temperature kneading for 2h, vacuum kneading was continued at this temperature for 1h, and the vacuum degree was less than -0.08MPa. The material was cooled and discharged to obtain a precipitated liquid silicone rubber base rubber material.

[0071] Example 12

[0072] 2500g of 10000mPa·s vinyl-terminated polydimethylsiloxane, 60g of the mixture prepared in Example 1, and 240g of hydroxy silicone oil with a hydroxyl value of 12% were added to a closed kneader, and 1200g of precipitated silica was added to the kneader in 5 portions over 60 minutes. The kneading was started and the temperature was raised to 90°C. After the rubber material was kneaded into a mass, the temperature was raised to 150°C. After constant temperature kneading for 2h, vacuum kneading was continued at this temperature for 1h, and the vacuum degree was less than -0.08MPa. The material was cooled and discharged to obtain a precipitated liquid silicone rubber base rubber material.

[0073] Embodiment 13

[0074] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 150° C., and the mixture was kneaded at a constant temperature for 120 min to obtain a mixture.

[0075] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0076] Embodiment 14

[0077] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 90° C., and the mixture was kneaded at a constant temperature for 150 min to obtain a mixture.

[0078] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0079] Embodiment 15

[0080] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 170° C., and the mixture was kneaded at a constant temperature for 60 min to obtain a mixture.

[0081] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0082] Comparative Example 1

[0083] 2500g 10000mPa·s vinyl-terminated polydimethylsiloxane, 2g ethylene glycol, 20g mold release agent, 240g hydroxy silicone oil with a hydroxyl value of 5% were added to a closed kneader, and 1200g precipitated silica was added to the kneader in 5 portions over 60 minutes. The kneading was started and the temperature was raised to 90°C. After the rubber compound was kneaded into a mass, the temperature was raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading was continued at this temperature for 1 hour, and the vacuum degree was less than -0.08MPa. The material was cooled and discharged to obtain a precipitated liquid silicone rubber base rubber compound.

[0084] Comparative Example 2

[0085] 2500g 10000mPa·s vinyl-terminated polydimethylsiloxane, 20g release agent, 240g hydroxy silicone oil with hydroxyl value of 5% were added to a closed kneader, and 1200g precipitated silica was added to the kneader in 5 portions over 60 minutes. The kneading was started and the temperature was raised to 90°C. After the rubber compound was kneaded into a mass, the temperature was raised to 150°C. After kneading at a constant temperature for 2 hours, vacuum kneading was continued at this temperature for 1 hour, and the vacuum degree was less than -0.08MPa. The material was cooled and discharged to obtain a precipitated liquid silicone rubber base rubber compound.

[0086] Comparative Example 3

[0087] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading process was started, the temperature was raised to 60° C., and the mixture was kneaded at a constant temperature for 180 min to obtain a mixture.

[0088] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0089] Comparative Example 4

[0090] (1) 1000 g of 10000 mPa·s vinyl-terminated polydimethylsiloxane, 50 g of ethylene glycol, and 500 g of a release agent were placed in a closed kneader, the kneading was started, the temperature was raised to 200° C., and the kneading was performed at a constant temperature for 10 minutes to obtain a mixture.

[0091] (2): Using the mixture prepared in operation (1), prepare a base rubber compound according to the steps (2) and (3) in Example 1.

[0092] The performance results of the precipitated liquid silicone rubber base rubber prepared in the above Examples 1 to 15 and Comparative Examples 1 to 4 are shown in Table 1. The appearance of the base rubber prepared in Example 1 is as follows: Figure 1 As shown, the basic rubber materials prepared in Comparative Examples 1 and 2 are as follows Figure 2 , Figure 3 shown.

[0093] Table 1 Summary of the performance results of precipitated liquid silicone rubber base materials

[0094]

[0095] Based on Table 1 Figure 1-3 It can be seen that the precipitated liquid silicone rubber base material for keys prepared by the present invention is translucent in appearance and has fluidity. After being stored for 6 months, the viscosity change rate is small and the degree of structuring is low.

[0096] The following application examples are combined with the above embodiments to further explain the present invention.

[0097] Application Example 1

[0098] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 1, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0099] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 1, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0100] Application Example 2

[0101] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 2, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0102] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 2, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0103] Application Example 3

[0104] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 3, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0105] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 3, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0106] Application Example 4

[0107] Preparation of glue A: Take 100 g of the basic rubber prepared in Example 4, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0108] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 4, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0109] Application Example 5

[0110] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 5, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0111] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 5, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0112] Application Example 6

[0113] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 6, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0114] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 6, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0115] Application Example 7

[0116] Preparation of glue A: Take 100 g of the basic rubber prepared in Example 7, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0117] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 7, add 0.10 g of acetylene cyclohexanol inhibitor and 0.65 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0118] Application Example 8

[0119] Preparation of glue A: Take 100 g of the basic rubber prepared in Example 8, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0120] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 8, add 0.10 g of acetylene cyclohexanol inhibitor and 0.58 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0121] Application Example 9

[0122] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 9, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0123] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 9, add 0.10 g of acetylene cyclohexanol inhibitor and 0.50 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0124] Application Example 10

[0125] Preparation of glue A: Take 100 g of the basic rubber prepared in Example 10, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0126] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 10, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0127] Application Example 11

[0128] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 11, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0129] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 11, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0130] Application Example 12

[0131] Preparation of glue A: Take 100 g of the basic rubber prepared in Example 12, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0132] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 12, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0133] Application Example 13

[0134] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 13, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0135] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 13, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0136] Application Example 14

[0137] Preparation of A glue: Take 100 g of the basic rubber prepared in Example 14, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0138] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 14, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0139] Application Example 15

[0140] Preparation of glue A: Take 100 g of the basic rubber prepared in Example 15, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0141] Preparation of B glue: Take 100 g of the basic rubber prepared in Example 15, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0142] Comparative application example 1

[0143] Preparation of glue A: Take 100 g of the basic rubber prepared in Comparative Example 1, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0144] Preparation of B glue: Take 100 g of the basic rubber prepared in Comparative Example 1, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0145] Comparative Application Example 2

[0146] Preparation of glue A: Take 100 g of the basic rubber prepared in Comparative Example 2, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0147] Preparation of B glue: Take 100 g of the basic rubber prepared in Comparative Example 2, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0148] Comparative Application Example 3

[0149] Preparation of glue A: Take 100 g of the basic rubber prepared in Comparative Example 3, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain glue A.

[0150] Preparation of B glue: Take 100 g of the basic rubber prepared in Comparative Example 3, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0151] Comparative Application Example 4

[0152] Preparation of A glue: Take 100 g of the basic rubber prepared in Comparative Example 4, add 1.72 g of 300 ppm Custer platinum catalyst thereto, mix well to obtain A glue.

[0153] Preparation of B glue: Take 100 g of the basic rubber prepared in Comparative Example 4, add 0.10 g of acetylene cyclohexanol inhibitor and 0.76 g of hydrogen-containing silicone oil with a hydrogen content of 0.70%, mix and stir evenly to obtain B glue.

[0154] The A glue and B glue prepared in the above application example were mixed evenly in a mass ratio of 1:1, poured into a mold and vacuum degassed, and vulcanized at 120°C for 5-10 minutes to obtain a silicone rubber sheet with a thickness of 2 mm and a hardness test block with a thickness of 6 mm.

[0155] The tensile strength, elongation at break and tear strength of the 2 mm thick sheet obtained above were measured, and the hardness was tested using a 6 mm thick hardness block. The test results are shown in Table 2.

[0156] Table 2 Summary of test results of precipitation liquid silicone rubber performance

[0157]

[0158]

[0159] As can be seen from Table 2, the precipitated liquid silicone rubber base rubber for keys prepared by the present invention has excellent performance after vulcanization, with a tensile property of up to 7 MPa and a tear strength of up to 21 kN / m.

Claims

1. A method for preparing a precipitated liquid silicone rubber base compound for high-performance buttons, characterized in that: The steps include: (1): vinyl-terminated polydimethylsiloxane, diol and zinc stearate are mixed and kneaded at elevated temperature to obtain a mixture; (2) The vinyl-terminated polydimethylsiloxane, the mixture, the high-hydroxyl-value hydroxy silicone oil and the precipitated silica are kneaded in sequence by heating, kneaded in a vacuum and then cooled to obtain a precipitated liquid silicone rubber base compound.

2. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: The vinyl-terminated polydimethylsiloxane in step (1) has a viscosity of 100 to 100,000 mPa·s, a vinyl content of 0.07 to 1.06 wt%, and a volatile content of ≤1.0%.

3. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: The vinyl-terminated polydimethylsiloxane in step (1) is one vinyl-terminated polydimethylsiloxane with a viscosity of 100 to 100,000 mPa·s or a combination of two or more vinyl-terminated polydimethylsiloxanes.

4. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: In step (1), the diol is a cosolvent, which is ethylene glycol, propylene glycol, butylene glycol or a mixture thereof.

5. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: In step (1), kneading at 80 to 180° C. for 20 to 120 minutes; In step (2), kneading is performed at 130-180°C for 1-6 hours and then kneading is performed at a vacuum degree of -0.08--0.1 MPa for 0.5-2 hours. In step (1), the mass ratio of the vinyl-terminated polydimethylsiloxane, the diol, and the release agent is 1:0.01-0.5:0.1-2, preferably 1:0.02-0.3:0.5-1.

5.

6. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: The high hydroxyl value hydroxy silicone oil in step (2) is a small molecular hydroxy silicone oil with a hydroxyl content greater than 1.0% and a viscosity of 10 to 300 mPa·s.

7. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: The precipitated silica in step (2) is hydrophilic, with a specific surface area of ​​100 to 300 m 2 / g; precipitated silica is added in 4 to 10 portions within 30 to 120 minutes.

8. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: In step (2), the mass ratio of the vinyl-terminated polydimethylsiloxane, the mixture, the high-hydroxyl-value hydroxy silicone oil, and the precipitated silica is 40 to 80: 0.05～1：1～10：10～40。 9. A silicone rubber sheet, characterized in that: The precipitated liquid silicone rubber base compound for high-performance buttons is prepared according to the preparation method according to any one of claims 1 to 8.

10. The method for preparing a silicone rubber sheet according to claim 9, characterized in that: Preparation of glue A: adding Custer platinum catalyst to the high-performance precipitated liquid silicone rubber base for keys prepared by the method according to any one of claims 1 to 8, and mixing them evenly to obtain glue A; Preparation of B glue: adding acetylene cyclohexanol inhibitor and hydrogen-containing silicone oil to the high-performance precipitated liquid silicone rubber base rubber for keys prepared by the method according to any one of claims 1 to 8, and mixing and stirring to obtain B glue; After the A and B glues are mixed evenly, vacuum degassing is performed and the silicone rubber sheets are obtained by vulcanization at 120-130°C.

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