A silicone rubber tackifier, its preparation method and use

Abstract

The application belongs to the field of rubber auxiliaries, and particularly relates to a silicone rubber tackifier, a preparation method and application thereof. The silicone rubber tackifier prepared by the application can be adapted to most substrates, the two-component addition type silicone rubber prepared by using the silicone rubber tackifier has high storage stability, and has excellent performance in mechanical properties such as Shore hardness, shear strength, elongation at break, tensile strength and bonding reliability, and is suitable for fields such as electronic and electrical packaging, building sealing and automobile manufacturing.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of rubber auxiliaries, and particularly relates to a silicone rubber tackifier as well as a preparation method and application thereof. BACKGROUND

[0002] Molded silicone rubber is widely used in the fields of electronic and electrical packaging, building sealing, automobile manufacturing, etc. due to its excellent high-temperature resistance, weather resistance, electrical insulation, and low shrinkage. However, the molecular chain of pure addition-type silicone rubber has low polarity, and the adhesion to metal, glass, ceramic, and some polymer substrates is weak, which is difficult to meet the requirements of adhesion performance in practical applications. Therefore, the adhesion effect needs to be improved by adding tackifiers, which has become one of the key directions for the optimization of addition-type silicone rubber formulations.

[0003] Currently, the mainstream tackifiers for addition-type silicone rubber on the market are mainly single functional groups, such as epoxy, acyloxy, or siloxy compounds. Such tackifiers have obvious limitations: they can only effectively bond to specific types of substrates and cannot meet the bonding needs of multiple materials, resulting in the need to replace different tackifier formulations when facing multiple substrate composite scenarios, which increases production costs and process complexity. At the same time, some tackifiers have poor compatibility with silicone rubber substrates due to their molecular structure, which can cause problems such as delamination and precipitation, affecting the storage stability of silicone rubber and possibly leading to a decrease in mechanical properties such as tensile strength and elongation at break, making it difficult to meet the stringent requirements of high-end fields for comprehensive material performance.

[0004] In addition, in the development of existing tackifiers, some schemes attempt to broaden the substrate adaptation range by compounding multiple single-functional group compounds, but the compounded system is prone to insufficient synergistic effects due to differences in the reactivity of each component, which not only makes it difficult to achieve the desired bonding effect, but also may introduce impurities affecting the vulcanization process of silicone rubber. Another scheme introduces multi-functional group structures, but the proportion of functional groups and the molecular chain skeleton are not optimized, resulting in weak interfacial bonding between the tackifier and the silicone rubber matrix, or the inability to improve the mechanical properties of silicone rubber due to insufficient molecular rigidity. Therefore, developing a tackifier that has the synergistic effect of multiple functional groups, good compatibility, high storage stability, and can simultaneously improve the adhesion performance and mechanical properties of silicone rubber has become an urgent industry technical problem in the field of addition-type silicone rubber. SUMMARY

[0005] To solve the above technical problems, the present application provides a first aspect of a silicone rubber tackifier, the preparation raw materials of the silicone rubber tackifier include vinyl trimethoxysilane, boric acid, tetramethylcyclotetrasiloxane, allyl glycidyl ether, and methacryloyloxypropyl trimethoxysilane; wherein the vinyl trimethoxysilane and the boric acid are reacted to obtain product B1; the tetramethylcyclotetrasiloxane and the allyl glycidyl ether are reacted to obtain product B2; the product B1 and the product B2 are reacted to obtain product B3, and the product B3 and the methacryloyloxypropyl trimethoxysilane are reacted to obtain the silicone rubber tackifier.

[0006] The present application provides a second aspect of a preparation method of a silicone rubber tackifier, including the following steps:

[0007] S1, mixing the vinyl trimethoxysilane and the boric acid, adding a solvent, and heating at 150-160°C in an oil bath for 3-4h to obtain borosiloxane, denoted as product B1;

[0008] S2, mixing the tetramethylcyclotetrasiloxane and the allyl glycidyl ether, and heating at 40-50°C in an oil bath for 3-4h to obtain product B2;

[0009] S3, adding the product B1 to the product B2, and heating at 80-100°C in an oil bath for 3-4h to obtain product B3;

[0010] S4, adding the methacryloyloxypropyl trimethoxysilane dropwise to the product B3, and stirring for 3-4h to obtain the silicone rubber tackifier.

[0011] Further, the preparation method of the silicone rubber tackifier includes the following steps:

[0012] S1, mixing the vinyl trimethoxysilane and the boric acid, adding a solvent, and heating at 150-160°C in an oil bath for 3-4h to obtain borosiloxane, denoted as product B1;

[0013] ;

[0014] S2, mixing the tetramethylcyclotetrasiloxane, the allyl glycidyl ether, and the platinum catalyst, and heating at 40-50°C in an oil bath for 3-4h in an inert gas environment to obtain product B2; the reaction formula is:

[0015] ;

[0016] S3, adding the product B1 to the product B2 in an inert gas environment, and heating at 80-100°C in an oil bath for 3-4h to obtain product B3; the reaction formula is:

[0017] ;

[0018] S4, drop methyl acryloxypropyl trimethoxysilane into product B3, stir for 3-4h to obtain a crude product; add diatomite into the crude product, stir for 8-10h, filter to obtain a colorless transparent solution, and then perform vacuum distillation to obtain the silicone rubber tackifier; the reaction formula is:

[0019] .

[0020] As an implementable case, the mass ratio of vinyl trimethoxysilane to boric acid in the S1 step is (40-50):(5-10).

[0021] Further, the mass ratio of vinyl trimethoxysilane to boric acid in the S1 step is 44.4:9.27.

[0022] As an implementable case, the solvent in the S1 step includes diglyme.

[0023] As an implementable case, the mass ratio of tetramethylcyclotetrasiloxane, allyl glycidyl ether and Karstedt platinum catalyst in the S2 step is 100:(8-10):(0.1-0.3).

[0024] Further, the mass ratio of tetramethylcyclotetrasiloxane, allyl glycidyl ether and Karstedt platinum catalyst in the S2 step is 100:8.4:0.3.

[0025] The tackifier prepared by the method has a siloxane structure, is compatible with two-component addition type silicone rubber, can effectively avoid problems such as delamination and precipitation, and guarantees the storage stability of the silicone rubber; meanwhile, the tackifier molecule contains an epoxy group, an acyloxy group and a boron group, can be adapted to most substrates on the market, greatly widens the bonding application range, and solves the limitation that a single functional group tackifier can only be used for specific substrates; due to the rigid cyclosiloxane structure in the molecular structure, the two-component addition type silicone rubber prepared by using the tackifier has excellent mechanical properties, the rubber has higher shear strength, elongation at break and tensile strength, and the bonding failure can be effectively reduced.

[0026] The third aspect of the application provides an application of the silicone rubber tackifier.

[0027] As an implementable case, the two-component addition type silicone rubber comprises an A component and a B component, raw materials for preparing the A component comprise, in mass fraction, 50-100 parts of base glue, 0.1-0.5 parts of Karstedt platinum catalyst; raw materials for preparing the B component comprise, in mass fraction, 50-100 parts of base glue, 1-5 parts of hydrogen-containing silicone oil, 0.05-0.1 parts of acetylene cyclohexanol and 3-10 parts of silicone rubber tackifier.

[0028] As an implementable case, the base glue is prepared from raw materials comprising vinyl silicone oil and modified white carbon black.

[0029] Further, the vinyl silicone oil has a viscosity of 5000-20000 mPa·s at 25℃.

[0030] Further, the modified white carbon black is prepared from raw materials comprising modifier and fumed white carbon black.

[0031] Further, the modifier comprises hexamethyldisilazane.

[0032] In the present application, the reaction between hexamethyldisilazane and the surface hydroxyl groups of the white carbon black can reduce the surface polarity and the agglomeration tendency of the white carbon black, which can improve the dispersion uniformity of the white carbon black in the vinyl silicone oil matrix, avoid the problems of uneven mechanical properties and appearance defects of the base glue caused by agglomeration of the white carbon black, reduce the adverse effects of the surface hydroxyl groups of the white carbon black on the vulcanization process of the addition type silicone rubber, and enhance the interfacial bonding force between the white carbon black and the silicone rubber matrix, thereby ensuring that the two-component addition type silicone rubber prepared subsequently meets the design requirements in terms of mechanical properties and storage stability.

[0033] Advantages

[0034] (1) The silicone rubber tackifier prepared in the present application has epoxy groups, acyloxy groups and boron groups, which can meet the bonding requirements of most substrates on the market, solve the limitation of single functional group tackifier which can only be used for specific substrates, and reduce the production and process complexity without the need to change the tackifier formula due to the type of substrate.

[0035] (2) The silicone rubber tackifier prepared in the present application has siloxane structure, which is well adapted to the molecular structure of the addition type silicone rubber, can be uniformly dispersed in the silicone rubber system, and can effectively ensure the storage stability of the two-component addition type silicone rubber.

[0036] (3) The silicone rubber tackifier prepared in the present application contains rigid cyclosiloxane structure in the molecule, which can significantly improve the mechanical properties such as tensile strength, elongation at break and Shore hardness of the product when used for preparing the two-component addition type silicone rubber.

[0037] (Four) In the preparation of the base glue, the fumed silica modified by hexamethyldisilazane has better dispersibility, which can reduce the problem of uneven performance of the base glue caused by silica agglomeration, and at the same time, enhance the interfacial bonding force between the silica and the vinyl silicone oil matrix, laying a foundation for the performance of the subsequent silicone rubber to meet the standard.

[0038] (Five) The two-component addition type silicone rubber prepared by using the silicone rubber tackifier prepared in the present application can effectively improve the bonding strength between the base material and the product, reduce the bonding failure, and improve the bonding reliability of the product in actual application, which can be verified by 100°C constant temperature vulcanization and manual peeling evaluation method. DETAILED DESCRIPTION

[0039] Example 1

[0040] The present example provides a preparation method of a silicone rubber tackifier, which comprises the following steps:

[0041] S1, in a three-necked flask, 148 parts (44.4 g) of vinyltrimethoxysilane and 30.9 parts (9.27 g) of boric acid, 50 mL of diglycol dimethyl ether solvent, and 1 mL of concentrated hydrochloric acid as catalyst were added, and heated at 160°C under nitrogen atmosphere for 3h. After the reaction was completed, it was cooled to room temperature (about 25°C), and the diglycol dimethyl ether was distilled off under reduced pressure to obtain a borosiloxane, which was recorded as B1; the reaction formula is:

[0042] ;

[0043] S2, in a three-necked flask, 100 parts of tetramethylcyclotetrasiloxane, 8.4 parts of allyl glycidyl ether, and 0.3 parts of platinum catalyst were added in sequence, and heated at 40°C under nitrogen atmosphere for 4h with uniform stirring at a speed of 320 rpm to obtain product B2; the reaction formula is:

[0044] ;

[0045] S3, then 25 parts of the above product B1 were added to the three-necked flask containing product B2 in step S2, and heated at 80°C under nitrogen atmosphere for 4h with uniform stirring at a speed of 320 rpm; the temperature of the oil bath was kept at 80°C during the period, and product B3 was obtained; the reaction formula is:

[0046] ;

[0047] S4, 24 parts of methacryloxypropyltrimethoxysilane was added dropwise into the product B3, the dropping time was 30 min, and the stirring was continued at a uniform speed for 4 h at a stirring speed of 320 rpm to obtain a crude product; diatomite was added into the crude product, stirring was continued for 8 h, filtration was performed to obtain a colorless transparent solution, and vacuum distillation was performed at -0.09 MPa and 140℃ to obtain the silicone rubber tackifier; the reaction formula is as follows:

[0048] .

[0049] Example 2

[0050] The example provides a silicone rubber tackifier prepared according to the preparation method of Example 1.

[0051] Example 3

[0052] The example provides an application of the silicone rubber tackifier of Example 2, which is applied in the preparation of a two-component addition type silicone rubber.

[0053] The raw materials for preparing the two-component addition type silicone rubber are an A component and a B component; the A component is 90 parts of a base glue, 0.3 parts of a Karstedt platinum catalyst (3000 ppm) according to the mass fraction; the B component is 90 parts of a base glue, 3 parts of a hydrogen-containing silicone oil, 0.08 parts of acetylene cyclohexanol, and 4 parts of a silicone rubber tackifier according to the mass fraction.

[0054] The preparation method of the base glue is as follows: 80 parts of a vinyl silicone oil with a viscosity of 20000 mPa.s (25℃) and 20 parts of a vinyl silicone oil with a viscosity of 5000 mPa.s (25℃) are added into a kneader, and stirring is performed at room temperature (about 25℃) for 5 min; then 30 parts of fumed white carbon black with a specific surface area of 200 m² / g modified by hexamethyldisilazane is added in two batches, mixing is performed at room temperature for 2 h, vacuum stirring is performed at a temperature of 150℃ for 2 h, and cooling is performed to room temperature to obtain the base glue.

[0055] The preparation method of the two-component addition type silicone rubber is as follows: 90 parts of the base glue and 0.3 parts of the Karstedt platinum catalyst are stirred in a dynamic mixer for 30 min under vacuum to obtain the A component; 90 parts of the base glue, 3 parts of the hydrogen-containing silicone oil, 0.08 parts of the acetylene cyclohexanol, and 4 parts of the silicone rubber tackifier are stirred in a dynamic mixer for 2 h under vacuum to obtain the B component. The prepared A component and B component are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0056] Example 4

[0057] The specific implementation of the example is the same as that of Example 3, and the difference is that:

[0058] The preparation method of the base adhesive is as follows: 60 parts of 20000 mPa.s (25℃) vinyl silicone oil and 40 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 40 parts of fumed silica with a specific surface area of 200 m2 / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0059] The preparation method of the two-component addition type silicone rubber is as follows: 80 parts of the base adhesive and 0.2 parts of the Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 80 parts of the base adhesive, 5 parts of the hydrogen-containing silicone oil, 0.06 parts of the acetylene cyclohexanol, and 8 parts of the silicone rubber tackifier are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0060] Example 5

[0061] The specific implementation of this example is the same as that of example 3, except that:

[0062] The preparation method of the base adhesive is as follows: 90 parts of 20000 mPa.s (25℃) vinyl silicone oil and 10 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 20 parts of fumed silica with a specific surface area of 200 m2 / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0063] The preparation method of the two-component addition type silicone rubber is as follows: 70 parts of the base adhesive and 0.4 parts of the Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 90 parts of the base adhesive, 4 parts of the hydrogen-containing silicone oil, 0.07 parts of the acetylene cyclohexanol, and 2 parts of the silicone rubber tackifier are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0064] Comparative Example 1

[0065] The specific implementation of this example is the same as that of example 3, except that:

[0066] The preparation method of the base adhesive is as follows: 80 parts of 20000 mPa.s (25℃) vinyl silicone oil and 20 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 30 parts of fumed white carbon black with a specific surface area of 200 m² / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0067] The preparation method of the two-component addition type silicone rubber is as follows: 90 parts of the base adhesive and 0.3 parts of Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 90 parts of the base adhesive, 3 parts of hydrogen-containing silicone oil, and 0.07 parts of acetylene cyclohexanol are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0068] Comparative Example 2

[0069] The specific implementation of this example is the same as that of Example 3, except that:

[0070] The preparation method of the base adhesive is as follows: 80 parts of 20000 mPa.s (25℃) vinyl silicone oil and 20 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 30 parts of fumed white carbon black with a specific surface area of 200 m² / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0071] The preparation method of the two-component addition type silicone rubber is as follows: 90 parts of the base adhesive and 0.3 parts of Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 90 parts of the base adhesive, 3 parts of hydrogen-containing silicone oil, and 0.07 parts of acetylene cyclohexanol are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0072] Comparative Example 3

[0073] The specific implementation of this example is the same as that of Example 3, except that:

[0074] The preparation method of the base adhesive is as follows: 80 parts of 20000 mPa.s (25℃) vinyl silicone oil and 20 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 30 parts of fumed white carbon black with a specific surface area of 200 m² / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0075] The preparation method of the two-component addition type silicone rubber is as follows: 90 parts of the base adhesive, 0.3 parts of Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 90 parts of the base adhesive, 3 parts of hydrogen-containing silicone oil, 0.08 parts of acetylene cyclohexanol, 1 part of allyl glycidyl ether, 2 parts of methacryloyloxypropyl triethoxysilane, and 1 part of tris(trimethylsilyl) borate are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0076] Comparative Example 4

[0077] The specific implementation of this example is the same as that of Example 3, except that:

[0078] The preparation method of the base adhesive is as follows: 80 parts of 20000 mPa.s (25℃) vinyl silicone oil and 20 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 30 parts of fumed white carbon black with a specific surface area of 200 m² / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0079] The preparation method of the two-component addition type silicone rubber is as follows: 90 parts of the base adhesive, 0.3 parts of Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 90 parts of the base adhesive, 3 parts of hydrogen-containing silicone oil, 0.08 parts of acetylene cyclohexanol, 4 parts of T907 (commercially available addition type silicone rubber tackifier) are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0080] Comparative Example 5

[0081] The specific implementation of this example is the same as that of Example 3, except that:

[0082] The preparation method of the base adhesive is as follows: 80 parts of 20000 mPa.s (25℃) vinyl silicone oil and 20 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 30 parts of fumed silica with a specific surface area of 200 m² / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0083] The preparation method of the two-component addition type silicone rubber is as follows: 90 parts of the base adhesive, 0.3 parts of Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 90 parts of the base adhesive, 3 parts of hydrogen-containing silicone oil, 0.08 parts of acetylene cyclohexanol, and 4 parts of intermediate product B3 are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0084] Comparative Example 6

[0085] The specific implementation of this example is the same as that of Example 3, except that:

[0086] The preparation method of the base adhesive is as follows: 80 parts of 20000 mPa.s (25℃) vinyl silicone oil and 20 parts of 5000 mPa.s (25℃) vinyl silicone oil are added into a kneader, stirred at room temperature (about 25℃) for 5 min; then 30 parts of fumed silica with a specific surface area of 200 m² / g modified by hexamethyldisilazane is added in two batches, mixed at room temperature for 2 h, heated to 150℃, vacuum stirred for 2 h, and cooled to room temperature to obtain the base adhesive;

[0087] The preparation method of the two-component addition type silicone rubber is as follows: 90 parts of the base adhesive, 0.3 parts of Karstedt platinum catalyst are vacuum stirred in a dynamic mixer for 30 min to obtain component A; 90 parts of the base adhesive, 3 parts of hydrogen-containing silicone oil, 0.08 parts of acetylene cyclohexanol, and 4 parts of intermediate product B3 are vacuum stirred in a dynamic mixer for 2 h to obtain component B. The prepared component A and component B are mixed in a mass ratio of 1:1 to obtain the two-component addition type silicone rubber.

[0088] Performance evaluation

[0089] Test object: the two-component addition type silicone rubber prepared in Examples 3-5 and Comparative Examples 1-6.

[0090] Test item and method:

[0091] 1. According to GB / T 531.1 2008 to test the Shore hardness of the adhesive;

[0092] 2. Shear strength was tested according to GB / T 7124-2008;

[0093] 3. Elongation at break and tensile strength were tested according to GB / T 528;

[0094] 4. The adhesive sample of 100mmx20mmx4mm or less in size (including PC: polycarbonate; PPA: polyphthalamide; ABS: acrylonitrile-butadiene-styrene copolymer; Al: aluminum) was selected, the silicone rubber was coated on the adhesive surface of the substrate, then the two adhesive surfaces of the substrate were folded and pressed gently, the distance between the adhesive surfaces was kept at 2mm, and the sample was placed in a constant temperature environment of 100℃ for vulcanization for 40min, and then cooled to room temperature. The rubber layer was manually peeled off from one side of the substrate, and the adhesion was evaluated according to the degree of cohesive failure area.

[0095] Wherein ★: cohesive failure degree≥90%, ●: 80%≤cohesive failure degree<90%, ♦: 60%≤cohesive failure degree<80%, ▲: 40%≤cohesive failure degree<60%, ■: 20%≤cohesive failure degree<40%, ▃: 0≤cohesive failure degree<20%. The experimental results are shown in Table 1.

[0096]

[0097] As can be seen from the experimental results in the table, the cohesive failure degree of Comparative Example 1 without adding the prepared silicone rubber tackifier of the application to the five substrates is the lowest grade, and the shear strength is only 0.26MPa; Comparative Examples 2-6 using single functional group oligomer compounding, commercially available tackifiers or tackifier intermediates, the cohesive failure degree of most substrates is in the low-middle grade, and the highest shear strength is only 1.99MPa. The cohesive failure degree of Examples 3-5 to the five substrates all reaches a higher grade, and the cohesive failure degree of Example 3 is the highest grade, and the shear strength is the lowest 2.32MPa and the highest 2.54MPa, proving that the prepared silicone rubber tackifier of the application can greatly enhance the adhesion strength of silicone rubber and the substrate.

[0098] The highest elongation at break of Comparative Examples 1-4 is only 382%, and the highest tensile strength is only 2.93MPa; Comparative Examples 5 and 6 have similar elongation at break and tensile strength to the examples, but the adhesion performance is poor. The Shore hardness of Examples 3-5 is stable at 35 to 37 Shore A, the elongation at break is 511% to 536%, and the tensile strength is 3.81MPa to 4.12MPa, realizing the synergistic improvement of adhesion performance and mechanical properties. At the same time, Comparative Examples 2-6 can only achieve good adhesion to 1-2 kinds of substrates, while Examples 3 to 5 can achieve efficient adhesion to PC, PPA, ABS, Al and stainless steel, five commonly used substrates, covering plastic and metal substrates, meeting the application requirements of multi-substrate composite scenes.

Claims

1. A process for the preparation of a silicone rubber tackifier, characterized in that, It comprises the following steps: S1, mixing vinyl trimethoxysilane and boric acid, adding solvent, heating in inert gas environment, 150-160℃ oil bath for 3-4h, after reaction, cooling, distilling solvent under reduced pressure, to obtain borosiloxane, recorded as B1; S2, mixing tetramethylcyclotetrasiloxane, allyl glycidyl ether and platinum catalyst, heating in inert gas environment, 40-50℃ oil bath for 3-4h, to obtain product B2; ； S3, adding product B1 to product B2, heating in inert gas environment, 80-100℃ oil bath for 3-4h, to obtain product B3; S4, adding methyl methacryloyloxypropyl trimethoxysilane to product B3, stirring for 3-4h, to obtain crude product; adding diatomite to crude product, stirring for 8-10h, filtering, to obtain colorless transparent solution, then distilling under reduced pressure, to obtain silicone rubber tackifier; 。 2. The method for preparing a silicone rubber tackifier according to claim 1, characterized by, The mass ratio of vinyl trimethoxysilane to boric acid in S1 is (40-50):(5-10).

3. The method for preparing the silicone rubber tackifier according to claim 1, characterized in that, The solvent in S1 comprises diglyme.

4. The method for preparing the silicone rubber tackifier according to claim 1, characterized in that, The mass ratio of tetramethylcyclotetrasiloxane, allyl glycidyl ether and platinum catalyst in S2 is 100:(8-10):(0.1-0.3).

5. A silicone rubber tackifier prepared by the preparation method of the silicone rubber tackifier according to any one of claims 1-4.

6. Use of a silicone rubber tackifier according to claim 5, characterized in that It is applied in preparation of two-component addition type silicone rubber.

7. Use of a silicone rubber tackifier according to claim 6, characterized in that The two-component addition type silicone rubber comprises component A and component B. The preparation raw material of component A comprises 50-100 parts of base glue, 0.1-0.5 parts of platinum catalyst, by mass fraction. The preparation raw material of component B comprises 50-100 parts of base glue, 1-5 parts of hydrogen-containing silicone oil, 0.05-0.1 parts of ethynylcyclohexanol, 3-10 parts of silicone rubber tackifier, by mass fraction.

8. Use of a silicone rubber tackifier according to claim 7, characterized in that The preparation raw material of base glue comprises vinyl silicone oil and modified white carbon black.

9. Use of a silicone rubber tackifier according to claim 8, characterized in that The viscosity of vinyl silicone oil at 25℃ is 5000-20000 mPa·s.

10. The use of a silicone rubber tackifier according to claim 8, characterized in that The preparation raw material of modified white carbon black comprises modifier and fumed white carbon black.

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