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

Abstract

The application discloses a preparation method and application of high-performance key-use precipitated liquid silicone rubber base material and belongs to the field of preparation of precipitated silicone rubber. Vinyl-terminated polydimethylsiloxane, dihydric alcohol and a release agent are mixed and then kneaded to obtain a mixture; the vinyl-terminated polydimethylsiloxane, the mixture, high-hydroxyl-value hydroxyl silicone oil and precipitated white carbon black are put into a closed kneader, the kneading is started and the temperature is raised to 80-120 DEG C, the temperature is raised to 130-180 DEG C after the rubber material is densely kneaded into a lump, the constant-temperature kneading is carried out and vacuum kneading is carried out; the material is discharged after cooling, the prepared precipitated liquid silicone rubber base material has fluidity and a translucent appearance. The process is a two-step method for preparing the precipitated liquid silicone rubber base material, the yellowing problem of the base material is avoided, and the translucent base material can be stably prepared; the dispersion effect of the white carbon black in the base material is better, the structural degree is low and the viscosity change rate is small after six months of storage; the mechanical properties after vulcanization are excellent, and the base material can be applied to the field of keys.

Description

Technical Field

[0001] This invention relates to the field of precipitated silicone rubber, and more specifically, to a method for preparing and applying a high-performance precipitated liquid silicone rubber base compound for keypads. Background Technology

[0002] Addition-type liquid silicone rubber (LSR) is a type of liquid silicone rubber based on vinyl-containing polysiloxanes. Using hydrogen-bonded oligomeric siloxanes as vulcanizing crosslinking agents and a platinum catalyst, it undergoes an addition reaction to form a network-structured elastomer. LSR is non-toxic, odorless, and possesses excellent weather resistance and chemical inertness, making it widely applicable and promising for the market.

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

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

[0005] Therefore, a method for preparing and applying a high-performance precipitated liquid silicone rubber base compound for keypads is proposed. Summary of the Invention

[0006] To address the aforementioned problems in existing technologies, this invention provides a method for preparing and applying a high-performance precipitated liquid silicone rubber base compound for keypads. The preparation process described in this invention is a two-step method, which avoids the yellowing problem of the base compound and can stably prepare a semi-transparent base compound. Furthermore, the silica dispersion in the base compound is better, and after 6 months of storage, the degree of structure is low, and the viscosity change rate is small; the mechanical properties are high after vulcanization. To achieve the above objectives, this invention provides the following technical solution:

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

[0008] (1): Vinyl-terminated polydimethylsiloxane, diol, and release agent are added to a closed kneader in a certain proportion, the kneading is started and the temperature is raised to 80-180℃, and kneaded at a constant temperature for 20-120 minutes to obtain a mixture.

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

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

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

[0012] The vinyl-terminated polydimethylsiloxane 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.

[0013] The diol is a co-solvent and is ethylene glycol, propylene glycol, butanediol, 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 hydroxyl silicone oil has a hydroxyl content greater than 1.0% and a viscosity of 10-300 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 with a specific surface area of ​​100–300 m². 2 / g, added in 4 to 10 portions over 30 to 120 minutes to ensure full combination with the vinyl-terminated polydimethylsiloxane, the mixture, and the high hydroxyl value hydroxyl silicone oil.

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

[0019] The precipitated liquid silicone rubber base compound prepared by the process method of the present invention has fluidity and a semi-transparent appearance. The silica dispersion effect in the base compound is better. After 6 months of storage, the degree of structure is low and the viscosity change rate is small. The mechanical properties are high after vulcanization.

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

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

[0022] Preparation of Glue A: Add Caster platinum catalyst to the high-performance key precipitated liquid silicone rubber base material prepared by the method described above, and mix evenly to obtain Glue A;

[0023] Preparation of Glue B: Add acetylene cyclohexanol inhibitor and hydrogen-containing silicone oil to the high-performance button precipitated liquid silicone rubber base material prepared by the method, mix and stir evenly to obtain glue B;

[0024] After mixing A and B evenly, vacuum degassing is performed, and then vulcanization is carried out at 120-130℃ for 3-10 minutes to obtain silicone rubber sheet.

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

[0026] The beneficial effects of this invention are as follows: This invention provides a high-performance precipitated liquid silicone rubber base compound for keypads, specifically disclosing a preparation method and application of a high-performance precipitated liquid silicone rubber base compound for keypads. The release agent used in this invention is zinc stearate, which has good release effect and low cost, and is widely used in the silicone rubber field. 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 silicone rubber base compound, if the dosage, processing temperature, and time are not properly controlled, the compound is prone to yellowing, directly affecting its performance. This invention provides a new base compound preparation process, which is a two-step preparation method. First, zinc stearate and diol are dissolved in vinyl-terminated polydimethylsiloxane at a certain temperature in a certain proportion. At this time, the powdered zinc stearate dissolves, forming a white paste or white slurry, obtaining a mixture, which is then added to the base compound preparation process. Although this method involves more experimental steps, the mixed paste can be prepared once and used multiple times without needing to be prepared and used immediately. The resulting base rubber compound has excellent properties, avoids the problem of yellowing, and can stably produce a semi-transparent base rubber compound. Furthermore, the silica dispersion in the base rubber compound is better, and after 6 months of storage, the degree of structure is low and the viscosity change rate is small. The mechanical properties after vulcanization are excellent. This invention effectively improves the performance of precipitated liquid silicone rubber, reduces production costs, is suitable for the button industry, and can replace most applications of fumed liquid silicone rubber, possessing significant market value and prospects.

[0027] Another technical solution of the present invention involves using the prepared base rubber compound to prepare precipitated silicone rubber AB, and then mixing and vulcanizing it at a mass ratio of 1:1 to obtain precipitated liquid silicone rubber for buttons. The precipitated liquid silicone rubber obtained after vulcanization has excellent properties, with tensile strength reaching 5 MPa or more, more preferably 6 MPa or more, and more preferably 7 MPa or more; tear strength reaching 16 kN / m or more, more preferably 18 kN / m or more, tear strength reaching 20 kN / m or more, and tear strength reaching 21 kN / m or more.

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

[0029] The preparation process of this invention is a "two-step method", which avoids the problem of yellowing of the base rubber compound and can stably prepare a semi-transparent base rubber compound; moreover, the dispersion effect of silica in the base rubber compound is better, and after 6 months of storage, the degree of structure is low and the viscosity change rate is small; the precipitated liquid silicone rubber after vulcanization has excellent mechanical properties. Attached Figure Description

[0030] Figure 1 The image shows the appearance of the base adhesive prepared in Example 1.

[0031] Figure 2 The image shows the appearance of the base adhesive prepared in Comparative Example 1.

[0032] Figure 3 The image shows the appearance of the base adhesive prepared in Comparative Example 2. Detailed Implementation

[0033] The present invention will be further explained below with reference to the embodiments, but the embodiments do not limit the present invention in any way.

[0034] Example 1

[0035] (1): 1000g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 50g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0036] (2): Add 2500g of vinyl-terminated polydimethylsiloxane (10000mPa·s), 60g of the mixture, and 240g of hydroxyl silicone oil with a hydroxyl value of 5% to a closed kneader. Add 1200g of precipitated silica in 5 portions over 60 minutes to the kneader. Start the kneading process and raise the temperature to 90°C. After the rubber compound is kneaded into a ball, raise the temperature to 150°C and knead at a constant temperature for 2 hours. Then, continue to knead under vacuum at this temperature for 1 hour, with a vacuum degree of less than -0.08MPa.

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

[0038] Example 2

[0039] (1): 800g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 80g of ethylene glycol, and 800g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0040] (2): Add 2520g of vinyl-terminated polydimethylsiloxane (10000mPa·s), 40g of the mixture, and 240g of hydroxyl silicone oil with a hydroxyl value of 5% to a closed kneader. Add 1200g of precipitated silica in 5 portions over 60 minutes to the kneader. Start the kneading process and raise the temperature to 90°C. After the rubber compound is kneaded into a ball, raise the temperature to 150°C and knead at a constant temperature for 2 hours. Then, continue to knead under vacuum at this temperature for 1 hour, with a vacuum degree of less than -0.08MPa.

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

[0042] Example 3

[0043] (1): 600g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 90g of ethylene glycol, and 900g of release agent were put into a closed kneader, kneaded and heated to 140℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0044] (2): Add 2525g of vinyl-terminated polydimethylsiloxane (10000mPa·s), 35g of the mixture, and 240g of hydroxyl silicone oil with a hydroxyl value of 5% to a closed kneader. Add 1200g of precipitated silica in 5 portions over 60 minutes to the kneader. Start the kneading process and raise the temperature to 90°C. After the rubber compound is kneaded into a ball, raise the temperature to 150°C and knead at a constant temperature for 2 hours. Then, continue to knead under vacuum at this temperature for 1 hour, with a vacuum degree of less than -0.08MPa.

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

[0046] Example 4

[0047] (1): 1000g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 25g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0048] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0049] Example 5

[0050] (1): 1000g of vinyl-terminated polydimethylsiloxane with a viscosity of 10000mPa·s, 75g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0051] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0052] Example 6

[0053] (1): 1000g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 125g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0054] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0055] Example 7

[0056] (1): 1000g of vinyl-terminated polydimethylsiloxane at 20000mPa·s, 50g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0057] (2): Add 2500g of vinyl-terminated polydimethylsiloxane with a hydroxyl value of 20000mPa·s, 60g of the mixture, and 240g of hydroxyl silicone oil with a hydroxyl value of 5% to a closed kneader. Add 1200g of precipitated silica to the kneader in 5 portions over 60min. Start the kneading process and raise the temperature to 90℃. After the rubber compound is kneaded into a ball, raise the temperature to 150℃ and knead at a constant temperature for 2h. Then continue to knead under vacuum at this temperature for 1h. The vacuum degree is less than -0.08MPa.

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

[0059] Example 8

[0060] (1): 1000g of vinyl-terminated polydimethylsiloxane at 60000mPa·s, 50g of propylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0061] (2): Add 2500g of vinyl-terminated polydimethylsiloxane (60000mPa·s), 60g of the mixture, and 240g of hydroxyl silicone oil with a hydroxyl value of 5% to a closed kneader. Add 1200g of precipitated silica in 5 portions over 60 minutes to the kneader. Start the kneading process and raise the temperature to 90°C. After the rubber compound is kneaded into a ball, raise the temperature to 150°C and knead at a constant temperature for 2 hours. Then, continue to knead under vacuum at this temperature for 1 hour, with a vacuum degree of less than -0.08MPa.

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

[0063] Example 9

[0064] (1): 1000g of vinyl-terminated polydimethylsiloxane with a viscosity of 100000mPa·s, 50g of butanediol, and 500g of release agent were put into a closed kneader, kneaded and heated to 130℃, kneaded at a constant temperature for 90min to obtain a mixture.

[0065] (2): Add 2500g of vinyl-terminated polydimethylsiloxane (100000mPa·s), 60g of the mixture, and 240g of hydroxyl silicone oil with a hydroxyl value of 5% to a closed kneader. Add 1200g of precipitated silica in 5 portions over 60 minutes to the kneader. Start the kneading process and raise the temperature to 90°C. After the rubber compound is kneaded into a ball, raise the temperature to 150°C and knead at a constant temperature for 2 hours. Then, continue to knead under vacuum at this temperature for 1 hour, with a vacuum degree of less than -0.08MPa.

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

[0067] Example 10

[0068] 2500g of vinyl-terminated polydimethylsiloxane (10000mPa·s), 60g of the mixture prepared in Example 1, and 240g of hydroxyl silicone oil with a hydroxyl value of 8% were added to a closed kneader. 1200g of precipitated silica was added to the kneader in five portions over 60 minutes. The kneading process was initiated and the temperature was raised to 90°C. After the rubber compound was kneaded into a clump, the temperature was raised to 150°C and kneaded at this constant temperature for 2 hours. Then, the compound was kneaded under vacuum at this temperature for another 1 hour, with a vacuum degree of less than -0.08MPa. The mixture was cooled and discharged to obtain the precipitated liquid silicone rubber base compound.

[0069] Example 11

[0070] 2500g of vinyl-terminated polydimethylsiloxane (10000mPa·s), 60g of the mixture prepared in Example 1, and 240g of hydroxyl silicone oil with a hydroxyl value of 10% were added to a closed kneader. 1200g of precipitated silica was added to the kneader in five portions over 60 minutes. The kneading process was initiated and the temperature was raised to 90°C. After the rubber compound was kneaded into a clump, the temperature was raised to 150°C and kneaded at this constant temperature for 2 hours. Then, the compound was kneaded under vacuum at this temperature for another 1 hour, with a vacuum degree of less than -0.08MPa. The mixture was cooled and discharged to obtain the precipitated liquid silicone rubber base compound.

[0071] Example 12

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

[0073] Example 13

[0074] (1): 1000g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 50g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 150℃, kneaded at a constant temperature for 120min to obtain a mixture.

[0075] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0076] Example 14

[0077] (1): 1000g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 50g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 90℃, kneaded at a constant temperature for 150min to obtain a mixture.

[0078] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0079] Example 15

[0080] (1): 1000g of vinyl-terminated polydimethylsiloxane with a viscosity of 10000mPa·s, 50g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 170℃, kneaded at a constant temperature for 60min to obtain a mixture.

[0081] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0082] Comparative Example 1

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

[0084] Comparative Example 2

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

[0086] Comparative Example 3

[0087] (1): 1000g of vinyl-terminated polydimethylsiloxane at 10000mPa·s, 50g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 60℃, kneaded at a constant temperature for 180min to obtain a mixture.

[0088] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0089] Comparative Example 4

[0090] (1): 1000g of vinyl-terminated polydimethylsiloxane with a viscosity of 10000mPa·s, 50g of ethylene glycol, and 500g of release agent were put into a closed kneader, kneaded and heated to 200℃, kneaded at a constant temperature for 10min to obtain a mixture.

[0091] (2): The base adhesive is prepared by using the mixture prepared in operation (1) according to the steps (2) and (3) in Example 1.

[0092] The performance results of the precipitated liquid silicone rubber base compounds prepared in Examples 1-15 and Comparative Examples 1-4 are shown in Table 1. The appearance of the base compound prepared in Example 1 is as follows. Figure 1 As shown, the base adhesives prepared in comparative examples 1 and 2 are as follows: Figure 2 , Figure 3 As shown.

[0093] Table 1. Summary of Performance Results of Precipitated Liquid Silicone Rubber Base Compound

[0094]

[0095] Based on Table 1 Figure 1-3 It is known that the precipitated liquid silicone rubber base material for buttons prepared by the present invention is semi-transparent in appearance, has fluidity, and exhibits a small viscosity change rate and low degree of structure after 6 months of storage.

[0096] The following application examples, in conjunction with the above embodiments, further explain the present invention.

[0097] Application Example 1

[0098] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 1, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0100] Application Example 2

[0101] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 2, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0103] Application Example 3

[0104] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 3, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0106] Application Example 4

[0107] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 4, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0109] Application Example 5

[0110] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 5, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain Glue A.

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

[0112] Application Example 6

[0113] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 6, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0115] Application Example 7

[0116] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 7, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0118] Application Example 8

[0119] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 8, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0121] Application Example 9

[0122] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 9, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0124] Application Example 10

[0125] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 10, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0127] Application Example 11

[0128] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 11, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0130] Application Example 12

[0131] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 12, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0133] Application Example 13

[0134] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 13, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0136] Application Example 14

[0137] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 14, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0139] Application Example 15

[0140] Preparation of Glue A: Take 100g of the base adhesive prepared in Example 15, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain glue A.

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

[0142] Comparative Application Example 1

[0143] Preparation of Glue A: Take 100g of the base adhesive prepared in Comparative Example 1, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain Glue A.

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

[0145] Comparative Application Example 2

[0146] Preparation of Glue A: Take 100g of the base adhesive prepared in Comparative Example 2, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain Glue A.

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

[0148] Comparative Application Example 3

[0149] Preparation of Glue A: Take 100g of the base adhesive prepared in Comparative Example 3, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain Glue A.

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

[0151] Comparative Application Example 4

[0152] Preparation of Glue A: Take 100g of the base adhesive prepared in Comparative Example 4, add 1.72g of 300ppm Castor platinum catalyst to it, and mix evenly to obtain Glue A.

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

[0154] The A and B adhesives prepared in the above application example are mixed evenly at a mass ratio of 1:1, poured into a mold, and then vacuum degassed. After vulcanization at 120℃ for 5-10 minutes, a silicone rubber sheet with a thickness of 2mm and a hardness test block with a thickness of 6mm are obtained.

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

[0156] Table 2 Summary of Performance Test Results of Precipitated Liquid Silicone Rubber

[0157]

[0158]

[0159] As shown in Table 2, the precipitated liquid silicone rubber for buttons prepared in this invention has excellent properties after vulcanization, with a tensile strength of up to 7 MPa and a tear strength of up to 21 kN / m.

Claims

1. A method for preparing a high-performance precipitated liquid silicone rubber base compound for keypads, characterized in that, Includes the following steps: (1): Mix vinyl-terminated polydimethylsiloxane, diol, and zinc stearate, and knead at 80~180℃ for 20~120min to obtain a mixture. The diol is a co-solvent, which is ethylene glycol, propylene glycol, butanediol, or a mixture thereof. The mass ratio of vinyl-terminated polydimethylsiloxane, diol, and zinc stearate is 1:0.01~0.5:0.1~2. (2): Vinyl-terminated polydimethylsiloxane, mixture, high hydroxyl value hydroxyl silicone oil and precipitated silica are kneaded sequentially by heating, vacuum kneading and then cooled to obtain precipitated liquid silicone rubber base material. The high hydroxyl value hydroxyl silicone oil is a small molecule hydroxyl silicone oil with a hydroxyl content greater than 1.0% and a viscosity of 10~300 mPa·s. The mass ratio of vinyl-terminated polydimethylsiloxane, mixture, high hydroxyl value hydroxyl silicone oil and precipitated silica is 40~80:0.05~1:1~10:10~40.

2. 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 viscosity of the vinyl-terminated polydimethylsiloxane is 100~100000 mPa·s, the vinyl content is 0.07~1.06wt%, and the volatile content is ≤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: In step (1), the vinyl-terminated polydimethylsiloxane is one vinyl-terminated polydimethylsiloxane with a viscosity of 100~100000 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 (2), kneading is carried out at 130~180℃ for 1~6h and then kneaded at a vacuum of -0.08~-0.1MPa for 0.5~2h.

5. The method for preparing the high-performance precipitated liquid silicone rubber base compound for buttons according to claim 1, characterized in that: The mass ratio of vinyl-terminated polydimethylsiloxane, diol, and zinc stearate is 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: In step (2), the precipitated silica is hydrophilic with a specific surface area of ​​100~300 m². 2 / g; Precipitated silica is added in 4 to 10 portions over 30 to 120 minutes.

7. A silicone rubber sheet, characterized in that, The preparation method according to any one of claims 1 to 6 is used to prepare a high-performance precipitated liquid silicone rubber base compound for keypads.

8. The method for preparing silicone rubber sheet according to claim 7, characterized in that, Preparation of Glue A: Add Castel platinum catalyst to the high-performance button precipitated liquid silicone rubber base material prepared by the method of any one of claims 1 to 6, and mix evenly to obtain Glue A; Preparation of Glue B: Add acetylene cyclohexanol inhibitor and hydrogen-containing silicone oil to the high-performance button precipitated liquid silicone rubber base material prepared by the method of any one of claims 1 to 6, and mix and stir evenly to obtain glue B. After mixing A and B evenly, vacuum degassing is performed, and then vulcanization is carried out at 120~130℃ to obtain silicone rubber sheets.

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