A single-coat high thermal conductivity rubber-metal adhesive and its preparation process

Abstract

The present invention relates to the field of C09J107 / 00, specifically a single-coat, highly thermally conductive rubber-to-metal adhesive and its preparation process. The raw materials for the preparation, calculated by weight, include at least: 5-25% film-forming agent, 5-15% functional rubber, 5-15% adhesion promoter, 1-10% carbon black, and the remainder solvent. By introducing a self-designed thermally conductive adhesion promoter and treating hollow nanospheres with a nitro-compound-modified coupling agent, the hollow nanospheres, upon addition to the adhesive, can cross-link with the active ingredients in both the adhesive and the rubber and rapidly transfer heat during the vulcanization process, ensuring coordinated vulcanization of the adhesive and rubber. Compared to conventional adhesives, the adhesive exhibits higher thermal conductivity, resolving the problem of thin adhesive adhesion when conventional adhesives are used to bond thick products.

Description

Technical Field

[0001] The present invention relates to the field of C09J107 / 00, and in particular to a single-coat high-thermal-conductivity rubber-metal adhesive and a preparation process thereof. Background Art

[0002] At present, rubber-metal bonding products are widely used for vibration reduction and sealing purposes. They maintain the rigidity of metal while taking into account the elasticity of rubber, and can perfectly match these application scenarios. Therefore, rubber-metal adhesives are widely used in automotive parts, plate bearings, vibration isolation bearings, rubber tracks, dock fenders and other industries.

[0003] Chinese invention patent CN1969025B discloses an adhesive composition, a method for bonding to a metal surface, and a rubber-metal adhesive. Specifically, the adhesive is prepared by combining an elastomer-metal adhesive fluid composition with microspheres to produce an elastomer-metal adhesive with a viscosity of less than 500 cps. While the adhesive exhibits improved sprayability, the thick rubber makes heat transfer difficult during vulcanization bonding of thick products. Heat is primarily transferred from the metal surface to the adhesive surface, and then through the adhesive surface to the bonding interface. During this process, the adhesive's low thermal conductivity creates a significant temperature difference with the rubber at the bonding interface, leading to a reaction rate mismatch during vulcanization bonding. This ultimately results in low bond interface strength, thin rubber failure in destructive testing, and, in severe cases, adhesive failure. Summary of the Invention

[0004] Therefore, in response to the above defects, the present invention provides a single-coat high thermal conductivity rubber metal adhesive, which has higher thermal conductivity than traditional adhesives and effectively solves the problem of thin layer adhesion when traditional adhesives are used to bond thick products.

[0005] In one aspect, the present invention provides a single-coat high thermal conductivity rubber-metal adhesive, wherein the raw materials for its preparation include, by weight percentage, at least: 5-25% film-forming agent, 5-15% functional rubber, 5-15% adhesion promoter, 1-10% carbon black, and the remainder solvent;

[0006] As a preferred technical solution, the raw materials for preparing the single-coat high thermal conductivity rubber-metal adhesive include, by weight percentage, at least: 5-10% film-forming agent, 7-11% functional rubber, 8-12% adhesion promoter, 2-5% carbon black, and the balance solvent.

[0007] As a preferred technical solution, the film-forming agent is at least one of chlorinated rubber, highly chlorinated chloroprene rubber, chlorinated polyethylene, and chlorinated polypropylene. Preferably, the film-forming agent is chlorinated rubber. The chlorinated rubber is of the brand S170 or S130, sourced from Bayer.

[0008] As a preferred technical solution, the functional rubber is one or a combination of chlorosulfonated polyethylene, chlorosulfonated polypropylene, polyisoprene, brominated polyethylene, brominated polypropylene, and brominated butyl rubber. Preferably, the functional rubber is brominated butyl rubber.

[0009] As a preferred technical solution, the adhesion promoter is a silane-modified porous inorganic filler-supported nitro compound; in parts by weight, the raw materials for preparing the silane-modified porous inorganic filler-supported nitro compound include at least 20-40 parts of porous inorganic filler, 30-50 parts of silane acetone solution, and 20-40 parts of nitro compound solution.

[0010] As a preferred technical solution, the porous inorganic filler is at least one of alumina, magnesium oxide, aluminum nitride, silicon carbide, and silicon micropowder; preferably, the porous inorganic filler is alumina, aluminum nitride, and silicon carbide; preferably, the porous inorganic filler is porous alumina microspheres, porous aluminum nitride microspheres, and porous silicon carbide microspheres.

[0011] As a preferred technical solution, the mass concentration of silane in the silane acetone solution is 10-20%;

[0012] As a preferred technical solution, the silane is at least one of 3-aminopropyltrimethoxysilane, 1-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and methyltriethoxysilane; preferably, the silane is vinyltrimethoxysilane.

[0013] As a preferred technical solution, the mass concentration of the nitro compound in the nitro compound solution is 20-30%; preferably, the solvent in the nitro compound solution is toluene. Preferably, the nitro compound is at least one of nitrobenzene, nitrosobenzene, p-nitrotoluene, p-nitrosotoluene, p-dinitrosobenzene, m-dinitrosobenzene, and o-dinitrosobenzene; preferably, the nitro compound is p-dinitrosobenzene. Based on the system of the present invention, the hollow nanospheres treated with a coupling agent modified with a nitro compound, especially p-dinitrosobenzene, can, upon addition to the adhesive, produce a cross-linking reaction with the active ingredients in the adhesive and rubber, while also rapidly transferring heat during the vulcanization process, ensuring coordinated vulcanization of the adhesive and rubber.

[0014] As a preferred technical solution, the preparation method of the silane-modified porous inorganic filler-supported nitro compound is as follows: soaking the porous inorganic filler in a silane acetone solution at 65-75°C for 100-150 minutes, filtering and drying, and then soaking it in a nitro compound solution at 40-60°C for 3-5 hours, and obtaining the adhesion promoter after drying.

[0015] Based on the system of the present invention, porous alumina microspheres or porous aluminum nitride microspheres or porous silicon carbide microspheres are fully combined with specific silanes and nitro compounds under specific process conditions to prepare silane-modified porous inorganic filler-supported nitro compounds as bonding promoters for the adhesive system. In particular, when the amount of the bonding promoter introduced is controlled to 8-12% of the total mass of the formula, it can interact with the functional rubber, film-forming agent, and carbon black raw materials in the adhesive system to enhance cross-linking and thermal conductivity, so that the prepared adhesive has significantly improved thermal conductivity. During the vulcanization process, heat can be quickly transferred to the bonding interface, thereby achieving synchronization with the vulcanization of the rubber, effectively solving the problem of thin layer adhesion when traditional adhesives are used to bond thick products.

[0016] As a preferred technical solution, the model of the carbon black is at least one of N326, N330, N550, N660, N762, and N774; preferably, the iodine absorption value of the carbon black is 29-43 g / kg; most preferably, the model of the carbon black is N762.

[0017] As a preferred technical solution, the solvent is one or a mixture of xylene, toluene, ethylbenzene, and n-butyl propionate;

[0018] On the other hand, the present invention provides a preparation process for a single-coat high thermal conductivity rubber-metal adhesive. The process comprises adding a film-forming agent, a functional rubber, an adhesion promoter, and carbon black to a solvent according to mass percentage, stirring and mixing the mixture, and then grinding the mixture in a 0.3L horizontal sand mill in a laboratory until the fineness is less than 15 μm.

[0019] Beneficial effects

[0020] 1. The present invention provides a single-coat high thermal conductivity rubber metal adhesive, which has higher thermal conductivity than traditional adhesives and effectively solves the problem of thin layer adhesion when traditional adhesives are used to bond thick products.

[0021] 2. Based on the system of the present invention, nitro compounds, especially nano hollow microspheres treated with a coupling agent modified with dinitrosobenzene, are used. When added to the adhesive, they can not only produce a cross-linking reaction with the active ingredients in the adhesive and rubber, but also quickly transfer heat during the vulcanization process, ensuring coordinated vulcanization of the adhesive and rubber.

[0022] 3. Based on the system of the present invention, porous alumina microspheres or porous aluminum nitride microspheres or porous silicon carbide microspheres are fully combined with specific silanes and nitro compounds under specific process conditions to prepare silane-modified porous inorganic filler-supported nitro compounds as bonding promoters for the adhesive system. In particular, when the amount of the bonding promoter introduced is controlled to 8-12% of the total mass of the formula, it can interact with the functional rubber, film-forming agent, and carbon black raw materials in the adhesive system to enhance cross-linking and thermal conductivity, so that the prepared adhesive has significantly improved thermal conductivity. During the vulcanization process, heat can be quickly transferred to the bonding interface, thereby achieving synchronization with the vulcanization of the rubber, effectively solving the problem of thin layer adhesion when traditional adhesives are used to bond thick products. DETAILED DESCRIPTION

[0023] Example 1

[0024] In one aspect, embodiment 1 of the present invention provides a single-coat high thermal conductivity rubber-metal adhesive, wherein the raw materials for its preparation include, by weight percentage: 6% film-forming agent, 8% functional rubber, 8% adhesion promoter, 2.5% carbon black, and the remainder solvent;

[0025] The film-forming agent is chlorinated rubber, the brand of which is S170 and is sourced from Bayer.

[0026] The functional rubber is brominated butyl rubber; the brominated butyl rubber comes from Sinopec Yanshan Petrochemical Company

[0027] The adhesion promoter is a nitro compound supported by a silane-modified porous inorganic filler; in parts by weight, the raw materials for preparing the nitro compound supported by a silane-modified porous inorganic filler include 30 parts of porous inorganic filler, 40 parts of silane acetone solution, and 30 parts of nitro compound solution.

[0028] The porous inorganic filler is porous alumina microspheres; the porous alumina microspheres are sourced from Shandong Bairui Chemical Co., Ltd.

[0029] The mass concentration of silane in the silane acetone solution is 15%;

[0030] The silane is vinyltrimethoxysilane.

[0031] The mass concentration of the nitro compound in the nitro compound solution is 25%; the solvent in the nitro compound solution is toluene. The nitro compound is p-dinitrosobenzene.

[0032] The preparation method of the silane-modified porous inorganic filler-supported nitro compound is as follows: the porous inorganic filler is immersed in a silane acetone solution at 80° C. for 120 minutes, filtered and dried, and then immersed in a nitro compound solution at 50° C. for 4 hours, and the adhesion promoter is obtained after drying.

[0033] The carbon black is of type N762.

[0034] The solvent is xylene.

[0035] On the other hand, Example 1 of the present invention provides a preparation process for a single-coat high thermal conductivity rubber-metal adhesive, comprising adding a film-forming agent, a functional rubber, an adhesion promoter, and carbon black to a solvent according to mass percentage, stirring and mixing the mixture, and then grinding the mixture in a 0.3L horizontal sand mill in a laboratory until the fineness is <15 μm.

[0036] Example 2

[0037] Example 2 of the present invention provides a single-coat high thermal conductivity rubber metal adhesive and its preparation process. Its specific implementation method is the same as that of Example 1, except that the porous inorganic filler is porous aluminum nitride microspheres; the porous aluminum nitride microspheres are sourced from Fujian Huaqing Electronic Materials Technology Co., Ltd.

[0038] Example 3

[0039] Example 3 of the present invention provides a single-coat high thermal conductivity rubber metal adhesive and a preparation process thereof. Its specific implementation method is the same as that of Example 1, except that the porous inorganic filler is porous silicon carbide microspheres; the porous silicon carbide microspheres are custom-made and provided by a cooperative laboratory.

[0040] Example 4

[0041] Example 4 of the present invention provides a single-coat high thermal conductivity rubber metal adhesive and its preparation process. Its specific implementation method is the same as that of Example 1, except that, in terms of mass percentage, its preparation raw materials include: 6% film-forming agent, 8% functional rubber, 9.5% adhesion promoter, 2.5% carbon black, and solvent to make up the balance; the porous inorganic filler is porous aluminum nitride microspheres; the porous aluminum nitride microspheres are sourced from Fujian Huaqing Electronic Materials Technology Co., Ltd.

[0042] Example 5

[0043] Example 5 of the present invention provides a single-coat high thermal conductivity rubber metal adhesive and its preparation process. Its specific implementation method is the same as that of Example 1, except that, in terms of mass percentage, its preparation raw materials include: 6% film-forming agent, 8% functional rubber, 11% adhesion promoter, 2.5% carbon black, and solvent to make up the balance. The porous inorganic filler is porous aluminum nitride microspheres; the porous aluminum nitride microspheres are sourced from Fujian Huaqing Electronic Materials Technology Co., Ltd.

[0044] Performance testing methods

[0045] (1) Adhesive Heat Transfer Performance: A 100 mm x 100 mm area of 45# steel plate was uniformly coated with the adhesive product prepared in the example. Commercially available single-coat Polyton 830 and Chemlok 6150 were then compared. The adhesive dry film thickness was controlled at 30 μm. After sufficient drying and 12 hours of conditioning, the plate was placed on a hot plate at a constant temperature, adhesive surface facing upward. The temperature of the adhesive surface was measured after 120 seconds. The results are shown in Table 1.

[0046] Table 1

[0047]

[0048]

[0049] The above results show that the single-coat high thermal conductivity rubber metal adhesive provided by the present invention is far superior to traditional brands in terms of heat transfer, and the gap will widen as the temperature rises.

[0050] (2) Properties of adhesive products: The examples and commercially available single-coat Polyton 830 and Chemlok 6150 were applied to a rubber shock-absorbing block (size 58 mm*77 mm, rubber hardness 70°, rubber thickness 30 mm). The vulcanization conditions were controlled at 155°C, 720 s, and a vulcanization pressure of 9 MPa. The rubber adhesion rate and thin layer adhesion rate of the final adhesive product after destruction were recorded. The results are shown in Table 2.

[0051] Table 2

[0052] Adhesives Adhesion rate Thin layer adhesive rate Polyton830 83％ 79％ Chemlok6150 84％ 80％ Example 1 95％ 33％ Example 2 97％ 17％ Example 3 97％ 23％ Example 4 98％ 12％ Example 5 98％ 7％

[0053] The above results demonstrate that the single-coat, highly thermally conductive rubber-to-metal adhesive provided by the present invention exhibits a significantly superior adhesion rate compared to conventional grades when bonding thick products, while also achieving a significantly smaller adhesion area in thin layers. This invention effectively enhances the adhesive's thermal conductivity, rapidly transferring heat to the bonding interface during the bonding process, resulting in a superior bonding effect, a conclusion confirmed by the above results.

Claims

1. A single-coat high thermal conductivity rubber metal adhesive, characterized in that: The raw materials for its preparation include, by mass percentage, 6% film-forming agent, 8% functional rubber, 11% adhesion promoter, 2.5% carbon black, and the remainder of solvent, wherein the film-forming agent is chlorinated rubber, and the brand of the chlorinated rubber is S170; the functional rubber is brominated butyl rubber; the adhesion promoter is a nitro compound supported by a silane-modified porous inorganic filler; by weight, the raw materials for the preparation of the nitro compound supported by the silane-modified porous inorganic filler include 30 parts of porous inorganic filler, 40 parts of silane acetone solution, and 30 parts of nitro compound solution; the porous inorganic filler is porous aluminum nitride microspheres; the mass concentration of silane in the silane acetone solution is 15%; the silane is vinyltrimethoxysilane; the nitro compound solution is 100% by weight. The mass concentration of the nitro compound in the solution is 25%; the solvent in the nitro compound solution is toluene; the nitro compound is p-dinitrosobenzene; the preparation method of the silane-modified porous inorganic filler-supported nitro compound is: immersing the porous inorganic filler in a silane acetone solution at 80°C for 120 minutes, filtering and drying, and then immersing it in a nitro compound solution at 50°C for 4 hours, and drying to obtain an adhesion promoter; the carbon black model is N762; the solvent is xylene; the preparation process of the single-coat high thermal conductivity rubber-metal adhesive is: adding a film-forming agent, functional rubber, adhesion promoter, and carbon black to a solvent according to mass percentage, stirring and mixing, and then grinding the mixture in a laboratory 0.3L horizontal sand mill to a fineness of <15μm.

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