Boron-containing adhesive addition type liquid silicone rubber

Abstract

The invention belongs to the technical field of organic silicon chemistry, and particularly relates to boron-containing adhesive addition type liquid silicone rubber. Boric acid reacts with hydroxyl vinyl silicone oil to prepare boron-containing vinyl silicone oil, the boron-containing vinyl silicone oil is used in an addition type liquid silicone rubber formula, and the formula further comprises vinyl-terminated silicone oil, hexamethyldisilazane, white carbon black, hydrogen-containing silicone oil, an alkynol inhibitor, a platinum catalyst and distilled water. The boron-containing vinyl silicone oil prepared by the invention is a part of silicone rubber, so that the problem of compatibility or stability does not exist. The adhesive addition type liquid silicone rubber disclosed by the invention has relatively good adhesion to a metal base material.

Description

Technical Field

[0001] The present invention relates to a boron-containing adhesive addition-type liquid silicone rubber, which is particularly suitable for high-strength demanding scenarios such as new energy vehicle battery pack sealing and metal substrate bonding, and belongs to the field of organosilicon chemistry. Background Art

[0002] In the field of organosilicon chemistry, the adhesion of silicone rubber has always been an important research topic. In order to improve the adhesion of silicone rubber, chemical modification is usually used to introduce reactive functional groups such as amino and epoxy groups into the molecular structure of silicone rubber. These functional groups can react chemically with the substrate to improve the adhesion. Although the existing technology has improved the adhesion between silicone rubber and the substrate to a certain extent, there are still some problems and limitations. The chemical modification method usually requires complex modification of the molecular structure of silicone rubber, which not only increases the production cost, but also may affect other excellent properties of silicone rubber. Therefore, how to improve the adhesion between silicone rubber and the substrate while simplifying the process and reducing costs is an important issue facing current technology.

[0003] In the comparative document CN105733497A, the boron-containing compound only reacts as a chain extender at 60-80°C, and its product is mainly Si-OB bond, which cannot directly improve the adhesion to the metal substrate. Summary of the invention

[0004] The purpose of the present invention is to develop a boron-containing adhesive addition-type liquid silicone rubber. The boron-containing vinyl silicone oil in the addition-type liquid silicone rubber of the present invention can significantly improve the adhesion between the silicone rubber and the metal substrate.

[0005] The technical solution of the present invention is as follows: A boron-containing vinyl silicone oil including -1 The characteristic absorption peak of the BO-Si bond is realized by grafting boron atoms onto the siloxane main chain structure to form boron-containing vinyl silicone oil.

[0006] The method for preparing the boron-containing vinyl silicone oil comprises the following steps: mixing hydroxy vinyl silicone oil and boric acid, stirring and reacting in an oil bath at 170-190° C. for 2-4 h to obtain the boron-containing vinyl silicone oil.

[0007] The mass ratio of hydroxy vinyl silicone oil to boric acid is 100:0.1-2. In some preferred cases, the mass ratio of hydroxy vinyl silicone oil to boric acid is 100:1.

[0008] The hydroxyl content of the hydroxy vinyl silicone oil is 2%-6%.

[0009] A boron-containing adhesive addition-type liquid silicone rubber, the raw materials are calculated by mass fraction, and the preparation process is as follows: 40-70 parts of base rubber, 40-60 parts of terminal vinyl silicone oil, 2-5 parts of terminal hydrogen-containing silicone oil, 0-2 parts of side hydrogen-containing silicone oil, 10-500 μL of acetylene alcohol inhibitor, 1-50 μL of Custer platinum catalyst and 1-5 parts of the boron-containing vinyl silicone oil or the boron-containing vinyl silicone oil prepared by the method are uniformly mixed to obtain a single-component boron-containing adhesive addition-type liquid silicone rubber.

[0010] The preparation process of the base rubber is as follows: 1500-1600 parts of vinyl-terminated silicone oil, 10-20 parts of distilled water, 100-120 parts of hexamethyldisilazane and 600-650 parts of white carbon black are added to a kneader and kneaded for 30-40 minutes, the temperature is raised to 150-160°C and kneaded for another 200-220 minutes, then the vacuum is turned on and the kneading is continued for 100-140 minutes, the heating is turned off, and the kneading is continued for 250-280 minutes to obtain the base rubber.

[0011] In some preferred cases, the preparation process of the base glue is as follows: 1517 parts of vinyl-terminated silicone oil, 20 parts of distilled water, 100 parts of hexamethyldisilazane and 600 parts of white carbon black are added to a kneader and kneaded for 30 minutes, the temperature is raised to 150°C and kneaded for another 210 minutes, then the vacuum is turned on and the kneading is continued for 120 minutes, the heating is turned off, and the kneading is continued for 270 minutes to obtain the base glue.

[0012] The preparation process of the boron-containing vinyl silicone oil is as follows: weigh 20 parts of hydroxy vinyl silicone oil and 0.2 parts of boric acid in a beaker, stir and react in an oil bath at 180°C for 3 hours to obtain boron-containing vinyl silicone oil. When reacting at 180°C, the infrared spectrum shows a significant absorption peak of the BO-Si bond (1340 cm⁻¹), indicating that the boron atom is successfully grafted to the siloxane main chain. The BO-Si structure generated by the high-temperature reaction of the present invention can form a stronger coordination bond with the oxygen atoms on the metal surface, thereby achieving a higher shear strength (3.2-4.2 MPa in Examples 3-5).

[0013] Preferably, the hydroxyl content of the hydroxy vinyl silicone oil is 2%-6%.

[0014] Preferably, the vinyl content of the vinyl-terminated silicone oil is 0.05-0.6 mol%.

[0015] Preferably, the hydrogen content of the terminal hydrogen-containing silicone oil and the side hydrogen-containing silicone oil is 0.1-2 mol%.

[0016] Preferably, the alkynol inhibitor is one or more of 2-butyne-1,4-diol, 3,5-dimethyl-1-hexyn-3-ol and 1-ethynyl-1-cyclohexanol.

[0017] Preferably, the specific surface area of ​​the white carbon black is 200-800 m 2 / g.

[0018] The beneficial effects of the present invention are: 1. The BO-Si bond structure generated by a high-temperature reaction at 170-190°C can form a stable coordination bond with oxygen atoms on the surface of the metal substrate, thereby increasing the shear strength to 3.2-4.2 MPa; 2. The compatibility of boron-containing vinyl silicone oil with the base glue is significantly better than that of conventional borate-modified products (such as the need to add additional hydroxy vinyl silicone oil to disperse silica in the comparative document CN105733497A), and there is no stratification after storage for 30 days; 3. After the reaction temperature and time are optimized, the generation of by-products is avoided (such as the incomplete reaction caused by the low-temperature reaction in comparative example 1). BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the infrared spectrum of the boron-containing vinyl silicone oil prepared in Example 1. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is described in detail below.

[0021] The raw materials used in the following examples of the present invention are all commercially available products; among them, vinyl silicone oil, hexamethyldisilazane and hydrogen-containing silicone oil are all provided by Zhejiang Runhe Silicone New Materials Co., Ltd.; white carbon black is provided by Huifu Nanomaterials Co., Ltd.; and platinum catalyst is provided by Shanghai Neutron Star Chemical Technology Co., Ltd.

[0022] Example 1 Preparation of Boron-Containing Vinyl Silicone Oil Weigh 20 parts of hydroxy vinyl silicone oil and 0.2 parts of boric acid in a beaker, stir and react in an oil bath at 180°C for 3 hours, centrifuge and take the supernatant after the reaction to obtain boron-containing vinyl silicone oil. The prepared boron-containing vinyl silicone oil includes -1 The characteristic absorption peak of the BO-Si bond is realized by grafting boron atoms onto the main chain structure of siloxane to form a boron-containing vinyl silicone oil. In addition, the infrared spectrum should also include the peak at 785 cm -1 The characteristic peaks of Si-CH3, 1008-1082 cm -1 The Si-O-Si characteristic peaks at 1257 cm -1 The Si-C characteristic peak and 2968 cm -1 The main absorption peaks include the characteristic peak of CH in the methyl group.

[0023] Example 2 Preparation of base glue Weigh 1517 parts of terminal vinyl silicone oil, 20 parts of distilled water, 100 parts of hexamethyldisilazane and 600 parts of white carbon black into a kneader and knead for 30 minutes. Raise the temperature to 150°C and knead for another 210 minutes. Then turn on the vacuum and continue kneading for 120 minutes. Turn off the heating and continue kneading for 270 minutes to obtain the base rubber.

[0024] Example 3 70 parts of the base rubber (prepared in Example 2) were mixed evenly with 50 parts of vinyl silicone oil, 3.33 parts of terminal hydrogenated silicone oil, 0.34 parts of side hydrogenated silicone oil, 2 parts of the boron-containing vinyl silicone oil prepared in Example 1, 200 μL of acetylene alcohol inhibitor and 30 μL of platinum catalyst; the mixture was placed in a vacuum drying oven for 24 h for degassing to obtain a boron-containing adhesive addition-type liquid silicone rubber 1.

[0025] Example 4 70 parts of the base rubber (prepared in Example 2) were mixed evenly with 60 parts of vinyl silicone oil, 4.13 parts of terminal hydrogenated silicone oil, 0.34 parts of side hydrogenated silicone oil, 3 parts of the boron-containing vinyl silicone oil prepared in Example 1, 200 μL of acetylene alcohol inhibitor and 30 μL of platinum catalyst; the mixture was placed in a vacuum drying oven for 24 h for degassing to obtain boron-containing adhesive addition-type liquid silicone rubber 2.

[0026] Example 5 50 parts of the base rubber (prepared in Example 2) were mixed evenly with 60 parts of vinyl silicone oil, 3.33 parts of terminal hydrogenated silicone oil, 1.34 parts of side hydrogenated silicone oil, 4 parts of the boron-containing vinyl silicone oil prepared in Example 1, 200 μL of acetylene alcohol inhibitor and 30 μL of platinum catalyst; the mixture was placed in a vacuum drying oven for 24 h for degassing to obtain a boron-containing adhesive addition-type liquid silicone rubber 1.

[0027] Comparative Example 1: Boron-containing vinyl silicone oil was prepared according to the method of Example 1, but the reaction temperature was adjusted to 160° C. and other conditions remained unchanged. The obtained product was used in the silicone rubber formulation of Example 3, and its shear strength on the aluminum substrate was tested to be 0.8 MPa, which was significantly lower than 3.2 MPa of Example 3.

[0028] Comparative Example 2: The trimethyl borate (reaction temperature 80°C) disclosed in CN105733497A was used to replace the boron-containing vinyl silicone oil of the present invention, and the silicone rubber was prepared according to the same formula. The shear strength was tested to be only 1.5 MPa, and delamination occurred after storage for 7 days, indicating poor compatibility.

[0029] Test Case The silicone rubbers 1 to 3 prepared in Examples 3 to 5 were coated on an aluminum substrate and cured by heating at 110° C. for 10 min. The shear strength of the cured silicone rubber was then tested according to GB / T 13936-92 “Test method for tensile shear strength of bond between vulcanized rubber and metal” as shown in Table 1. Table 1:

Claims

1. A boron-containing vinyl silicone oil, characterized in that: Included in 1340 cm -1 The infrared absorption peak is the characteristic absorption peak of the BO-Si bond, realizing the boron-containing vinyl silicone oil formed by the grafting of boron atoms to the siloxane main chain structure.

2. The method for preparing boron-containing hydroxyl vinyl silicone oil according to claim 1, characterized in that: The method comprises the following steps: mixing hydroxy vinyl silicone oil and boric acid, stirring and reacting in an oil bath at 170-190° C. for 2-4 hours to obtain boron-containing vinyl silicone oil.

3. The method for preparing boron-containing vinyl silicone oil according to claim 2, characterized in that: The mass ratio of hydroxyvinyl silicone oil to boric acid is 100:0.1-2.

4. The method for preparing boron-containing vinyl silicone oil according to claim 2, characterized in that: The hydroxyl content of the hydroxy vinyl silicone oil is 2%-6%.

5. A boron-containing adhesive addition-type liquid silicone rubber, characterized in that: The raw materials are calculated by mass fraction, and the preparation process is as follows: 40-70 parts of base rubber, 40-60 parts of terminal vinyl silicone oil, 2-5 parts of terminal hydrogen-containing silicone oil, 0-2 parts of side hydrogen-containing silicone oil, 10-500 μL of acetylene alcohol inhibitor, 1-50 μL of Custer platinum catalyst and 1-5 parts of the boron-containing vinyl silicone oil according to claim 1 or the boron-containing vinyl silicone oil prepared by the method according to any one of claims 2 to 4 are mixed evenly to obtain a single-component boron-containing adhesive addition-type liquid silicone rubber.

6. The boron-containing adhesive addition-type liquid silicone rubber according to claim 5, characterized in that: The preparation process of the base rubber is as follows: 1500-1600 parts of terminal vinyl silicone oil, 10-20 parts of distilled water, 100-120 parts of hexamethyldisilazane and 600-650 parts of white carbon black are added into a kneader and kneaded for 30-40 minutes, the temperature is raised to 150-160°C and kneaded for another 200-220 minutes, then the vacuum is turned on and the kneading is continued for 100-140 minutes, the heating is turned off, and the kneading is continued for 250-280 minutes to obtain the base rubber.

7. The boron-containing adhesive addition-type liquid silicone rubber according to claim 5, characterized in that: The vinyl content of the vinyl-terminated silicone oil is 0.05-0.6 mol %.

8. The boron-containing adhesive addition-type liquid silicone rubber according to claim 5, characterized in that: The hydrogen content of the terminal hydrogen-containing silicone oil and the side hydrogen-containing silicone oil is 0.1-2 mol%.

9. The boron-containing adhesive addition-type liquid silicone rubber according to claim 5, characterized in that: The alkynol inhibitor is one or more of 2-butyne-1,4-diol, 3,5-dimethyl-1-hexyn-3-ol and 1-ethynyl-1-cyclohexanol.

10. The boron-containing adhesive addition-type liquid silicone rubber according to claim 5, characterized in that: The specific surface area of ​​the white carbon black is 200-800 m 2 / g.

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