Rubber-metal heat vulcanization bonding double-coating type adhesive and preparation method thereof

Abstract

According to the rubber metal heat vulcanization bonding double-coating type adhesive and the preparation method thereof, allyl modified p-tert-octyl phenolic resin is introduced into a bottom coating adhesive and a surface coating adhesive at the same time to serve as tackifying resin, on one hand, the modified phenolic resin is provided with an alkyl long-chain structure and has similar compatibility with a rubber structure, and on the other hand, the modified phenolic resin has a long-chain structure; the physical riveting effect with rubber is enhanced; meanwhile, alkenyl unsaturated double bonds contained in the modified phenolic resin are subjected to chemical co-crosslinking with rubber in the vulcanization process, so that the vulcanization bonding performance of the surface coating adhesive and the rubber is improved; on the other hand, the prime coat adhesive and the top coat adhesive contain phenolic resin with the same structure, according to the principle of'similar dissolves like ', not only is the bonding strength of the prime coat adhesive and the top coat adhesive increased, but also the cohesion force between the prime coat adhesive and the top coat adhesive is enhanced, and therefore the bonding performance between the adhesives is improved.

Description

Technical Field

[0001] The invention belongs to the field of adhesives, and in particular relates to a rubber-metal hot-vulcanization bonding double-coating adhesive and a preparation method thereof. Background Art

[0002] As society continues to develop, more and more applications require the firm bonding of rubber and metal, including automobile manufacturing, shipbuilding, aerospace and other fields. Rubber and metal belong to two completely different material categories, organic polymer materials and inorganic metal materials, respectively, and the performance of the two materials themselves is significantly different. Therefore, it has become the focus of development in various industries to quickly and firmly bond these two completely different materials together to produce composite parts with the characteristics of rubber and metal.

[0003] Rubber-metal hot-vulcanized adhesive is currently the most effective solution for bonding metal and rubber. Existing rubber-metal hot-vulcanized adhesives include single-coat and double-coat adhesives. Single-coat hot-vulcanized adhesives only need to use one adhesive to achieve bonding when bonding rubber and metal. This adhesive is more convenient to use, but most single-coat hot-vulcanized adhesives cannot achieve effective bonding between metal and rubber, and have low bonding strength and poor bonding stability. Therefore, in the actual application of metal and rubber bonding, double-coat adhesives are still the main type. The primer adhesive of the double-coat adhesive can effectively bond with metal materials, while the top-coat adhesive can effectively bond with rubber, thereby solving the problem of bonding adhesives with two materials with significant modulus differences. However, the existing double-coat adhesives have poor bonding performance between the primer and top-coat adhesives, and are prone to adhesive cohesive failure, that is, failure between the top-coat and the primer. Summary of the invention

[0004] The purpose of the present invention is to solve the problem of poor bonding performance between the primer and the topcoat adhesives in the existing rubber-metal hot-vulcanization double-coating adhesive, and to provide a rubber-metal hot-vulcanization bonding double-coating adhesive and a preparation method thereof. The present invention introduces allyl-modified tert-octyl phenolic resin as a tackifying resin in the primer adhesive and the topcoat adhesive at the same time. On the one hand, the modified phenolic resin has an alkyl long-chain structure and has "similar compatibility" with the rubber structure, and forms a physical riveting effect with the rubber to enhance the bonding performance; at the same time, the modified phenolic resin contains olefinic unsaturated double bonds, which chemically cross-link with the rubber during the vulcanization process, thereby improving the vulcanization bonding performance of the topcoat adhesive and the rubber; on the other hand, the primer adhesive and the topcoat adhesive contain phenolic resins of the same structure. According to the principle of "like dissolves like", not only the bonding strength between the primer adhesive and the topcoat adhesive is increased, but also the cohesive force between the primer adhesive and the topcoat adhesive is enhanced, thereby improving the bonding performance between the adhesives.

[0005] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0006] Provided is a rubber-metal hot-vulcanization bonding double-coating adhesive, which includes a primer-coating adhesive and a top-coating adhesive. The primer-coating adhesive is composed of 5-10 parts of halogenated rubber, 5-10 parts of tackifying resin, 5-10 parts of coupling agent, 0.1-5 parts of dye, 1-8 parts of filler, and 50-60 parts of solvent in parts by weight; the top-coating adhesive is composed of 5-20 parts of halogenated rubber, 10-20 parts of tackifying resin, 1-10 parts of adhesion promoter, 1-10 parts of dye, and 65-125 parts of solvent in parts by weight. The halogenated rubber in the primer adhesive is one of chloroprene rubber, chlorosulfonated polyethylene rubber and chlorinated polyethylene rubber; the tackifying resin in the primer adhesive and the top coating adhesive is allyl-modified tert-octyl phenolic resin, and the weight ratio of the allyl-modified tert-octyl phenolic resin in the primer adhesive is controlled to be 5%-10%, and the weight ratio of the allyl-modified tert-octyl phenolic resin in the top coating adhesive is controlled to be 10%-20%.

[0007] The preparation method of the allyl-modified tert-octylphenol-formaldehyde resin comprises: (1) weighing tert-octylphenol and concentrated sulfuric acid in a four-necked bottle, placing a stirring paddle, a condenser and a thermometer, applying vacuum grease on the ground mouth to maintain the sealing of the system, and then placing the bottle in a preheated oil bath pot at 140° C., heating to melt the tert-octylphenol; (2) weighing acetaldehyde and transferring it to a constant pressure dropping funnel, when the tert-octylphenol is completely melted and the system temperature is 100-120° C., slowly adding acetaldehyde solution, the adding time is 3-5 hours, and the system temperature is 9 during the adding. 0-130℃; (3) After the acetaldehyde is dripped and the reaction continues for 1-2h, acrolein is slowly dripped, and the reaction is continued for 2-3h after the acrolein is dripped, and the reaction is stopped; (4) The mixture after the reaction is dissolved in toluene, and the amount of sodium hydroxide required is calculated according to the amount of acid, and an aqueous solution is prepared, added to the toluene solution, stirred and mixed, and after the aqueous phase is separated, the aqueous phase is washed twice with neutral water to separate the aqueous phase, and the organic phase is retained; (5) The organic phase is rotary evaporated at a rotary evaporation temperature of 120℃ until no liquid is distilled out, and vacuum dried at 200℃ for 2h to obtain allyl modified tert-octylphenol-formaldehyde resin. Among them, the molar ratio of tert-octylphenol to acetaldehyde is 1:0.7-1:0.95, acrolein accounts for 5-20wt% of tert-octylphenol, and concentrated sulfuric acid accounts for 5-10wt%.

[0008] The coupling agent in the primer-coating adhesive is one of γ-mercaptopropyltrimethoxysilane, propyl methacrylate trimethoxysilane, vinyl trimethoxysilane, and γ-glycidyloxypropyltrimethoxysilane; the dye in the primer-coating adhesive is carbon black; the filler in the primer-coating adhesive is one of titanium dioxide and zinc oxide or a combination of two; the solvent in the primer-coating adhesive is one of acetone, butanone, and methyl isobutyl ketone.

[0009] The halogenated rubber in the surface-coated adhesive is one of chlorosulfonated polyethylene rubber and chlorinated polyethylene rubber; the adhesion promoter in the surface-coated adhesive is a polynitroso aromatic compound; the dye in the surface-coated adhesive is carbon black; the solvent in the surface-coated adhesive is one of toluene, xylene, ethyl acetate, butyl acetate, and dimethyl carbonate, or a combination of several thereof.

[0010] The preparation method of the rubber-metal hot-vulcanization bonding double-coating adhesive comprises the following steps:

[0011] (1) Preparing a primer-coating adhesive: weighing 50-60 parts of a solvent and 5-10 parts of a kneaded halogenated rubber, adding them to a reactor, and stirring until they are completely dissolved; weighing 1-8 parts of a filler, 5-10 parts of a tackifying resin, 0.1-5 parts of a dye, and 5-10 parts of a coupling agent, sequentially adding them to a reactor, stirring, and dispersing them uniformly, and discharging the materials to obtain a primer-coating adhesive;

[0012] (2) Preparation of a top-coating adhesive: Weigh 65-125 parts of a solvent and 5-20 parts of a kneaded halogenated rubber, add them to a reactor, and stir until they are completely dissolved; weigh 10-20 parts of a tackifying resin and 1-10 parts of an adhesion promoter, add them to a reactor, stir, and disperse; add 1-10 parts of a dye three times, add them to the reactor, stir, and disperse, and discharge to obtain a top-coating adhesive.

[0013] The method for using the rubber-metal hot vulcanization bonding double-coating adhesive comprises the following steps:

[0014] (1) Stir both the primer and topcoat adhesives for 30 minutes before use;

[0015] (2) After sandblasting the metal surface to be bonded, wipe it with a cotton cloth dipped in alcohol, toluene or xylene and let it dry naturally for 3-5 minutes;

[0016] (3) Apply the stirred primer adhesive to the metal surface and apply a second coat after drying for a few minutes; (4) Apply the topcoat adhesive to the primer, dry it naturally for 1-2 hours, put it in an oven at 80°C for 10 minutes, and then hot-press vulcanize it at 150-170°C.

[0017] The application of the rubber-metal hot-vulcanization bonding double-coating adhesive is suitable for hot-vulcanization bonding of rubber and metal, wherein the rubber includes chloroprene rubber, nitrile rubber, styrene-butadiene rubber, butyl rubber, butadiene rubber, and ethylene-propylene rubber; the metal includes cast iron, carbon steel, stainless steel, alloy steel, aluminum, aluminum alloy, copper, and copper alloy.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention introduces allyl-modified tert-octylphenol-formaldehyde resin as a tackifying resin in both the primer adhesive and the top-coating adhesive. The allyl-modified tert-octylphenol-formaldehyde resin has an alkyl long-chain structure and has "similar compatibility" with the rubber structure, and forms a physical riveting effect with the rubber to enhance the bonding. At the same time, the modified phenolic resin contains olefinic unsaturated double bonds, which chemically cross-link with the rubber during the vulcanization process, thereby improving the vulcanization bonding performance of the top-coating adhesive and the rubber.

[0020] 2. Both the primer adhesive and the top coating adhesive of the present invention contain allyl-modified tert-octyl phenolic resin. Since the two adhesives contain phenolic resins with the same structure, according to the "like dissolves like" principle, during the rubber vulcanization process, the interaction force between the two adhesives is enhanced, that is, the cohesive force between the adhesives is enhanced, thereby improving the bonding performance between the adhesives.

[0021] 3. The present invention controls the weight ratio of the allyl-modified tert-octylphenolic resin in the primer adhesive to be 5%-10%, and the weight ratio of the allyl-modified tert-octylphenolic resin in the top-coating adhesive to be 10%-20%. Experimental data show that the two adhesives can achieve the best bonding performance by double coating. Within this ratio range, the effect of the allyl-modified tert-octylphenolic resin enables the interaction between the top-coating adhesive and the rubber, and between the top-coating adhesive and the primer adhesive to reach the best balance. DETAILED DESCRIPTION

[0022] In order to better introduce the technical solution of the present invention, the present invention is further described in conjunction with the following embodiments, but the embodiments are not all embodiments. And the protection scope is not limited to this, any changes or replacements that can be easily thought of by technicians familiar with the technical field within the technical scope of the present invention are all covered within the protection scope of the present invention.

[0023] Example 1

[0024] Preparation of primer adhesive 1: weighing 60 parts of methyl isobutyl ketone and 10 parts of kneaded chloroprene rubber, adding them into a reactor, stirring until completely dissolved; weighing 8 parts of titanium dioxide, 2 parts of zinc oxide, 4 parts of allyl-modified tert-octyl phenolic resin, 6 parts of carbon black, and 10 parts of γ-mercaptopropyltrimethoxysilane, adding them into a reactor in sequence, stirring, and dispersing them evenly, and discharging the primer adhesive 1, which contains 4wt% of allyl-modified tert-octyl phenolic resin;

[0025] Preparation of surface coating adhesive 1: weigh 70 parts of xylene and 9 parts of kneaded chlorosulfonated polyethylene rubber into a reactor and stir until completely dissolved; weigh 8 parts of allyl-modified tert-octyl phenolic resin and 5 parts of p-dinitrosobenzene into the reactor, stir and disperse; add 8 parts of carbon black into the reactor in three times, stir and disperse, and obtain surface coating adhesive 1, which contains 8wt% of allyl-modified tert-octyl phenolic resin.

[0026] Example 2

[0027] Preparation of primer adhesive 2: weighing 60 parts of methyl isobutyl ketone and 10 parts of kneaded chloroprene rubber, adding them into a reactor, stirring until completely dissolved; weighing 8 parts of titanium dioxide, 2 parts of zinc oxide, 5 parts of allyl-modified tert-octyl phenolic resin, 5 parts of carbon black, and 10 parts of γ-mercaptopropyltrimethoxysilane, adding them into a reactor in sequence, stirring, and dispersing them evenly, and discharging the primer adhesive 2, which contains 5wt% of allyl-modified tert-octyl phenolic resin;

[0028] Preparation of surface coating adhesive 2: weigh 70 parts of xylene and 8 parts of mixed chlorosulfonated polyethylene rubber into a reactor and stir until completely dissolved; weigh 10 parts of allyl-modified tert-octyl phenolic resin and 4 parts of dinitrosobenzene into the reactor, stir and disperse; add 8 parts of carbon black into the reactor in three times, stir and disperse, and obtain surface coating adhesive 2, which contains 10wt% of allyl-modified tert-octyl phenolic resin.

[0029] Example 3

[0030] Preparation of primer adhesive 3: weighing 60 parts of methyl isobutyl ketone and 9 parts of kneaded chloroprene rubber, adding them into a reactor, stirring until completely dissolved; weighing 6 parts of titanium dioxide, 2 parts of zinc oxide, 8 parts of allyl-modified tert-octyl phenolic resin, 5 parts of carbon black, and 10 parts of γ-mercaptopropyltrimethoxysilane, adding them into the reactor in sequence, stirring, and dispersing them evenly, and discharging the primer adhesive 3, which contains 8wt% of allyl-modified tert-octyl phenolic resin;

[0031] Preparation of surface coating adhesive 3: weigh 70 parts of xylene and 6 parts of mixed chlorosulfonated polyethylene rubber, add them into a reactor, and stir until completely dissolved; weigh 16 parts of allyl-modified tert-octyl phenolic resin and 3 parts of p-dinitrosobenzene, add them into the reactor, stir and disperse; add 5 parts of carbon black into the reactor in three times, stir and disperse, and obtain surface coating adhesive 3, which contains 16wt% of allyl-modified tert-octyl phenolic resin.

[0032] Example 4

[0033] Preparation of primer adhesive 4: weigh 60 parts of methyl isobutyl ketone and 8 parts of kneaded chloroprene rubber, add them to a reactor, and stir until completely dissolved; weigh 6 parts of titanium dioxide, 2 parts of zinc oxide, 10 parts of allyl-modified tert-octyl phenolic resin, 5 parts of carbon black, and 9 parts of γ-mercaptopropyltrimethoxysilane, add them to the reactor in sequence, stir, disperse evenly, and discharge to obtain primer adhesive 4, which contains 10wt% of allyl-modified tert-octyl phenolic resin; Preparation of top coating adhesive 4: weigh 65 parts of xylene and 7 parts of kneaded chlorosulfonated polyethylene rubber, add them to a reactor, and stir until completely dissolved; weigh 20 parts of allyl-modified tert-octyl phenolic resin and 3 parts of p-dinitrosobenzene, add them to the reactor, stir and disperse; add 5 parts of carbon black into the reactor in three times, stir and disperse, and discharge to obtain top coating adhesive 4, which contains 20wt% of allyl-modified tert-octyl phenolic resin.

[0034] Example 5

[0035] Preparation of primer adhesive 5: weigh 60 parts of methyl isobutyl ketone and 8 parts of kneaded chloroprene rubber, add them to a reactor, and stir until they are completely dissolved; weigh 6 parts of titanium dioxide, 1 part of zinc oxide, 12 parts of allyl-modified tert-octyl phenolic resin, 5 parts of carbon black, and 8 parts of γ-mercaptopropyltrimethoxysilane, add them to the reactor in sequence, stir, and disperse them evenly, and discharge the primer adhesive 5, which contains 12wt% of allyl-modified tert-octyl phenolic resin; Preparation of top coating adhesive 5: weigh 65 parts of xylene and 6 parts of kneaded chlorosulfonated polyethylene rubber, add them to a reactor, and stir until they are completely dissolved; weigh 24 parts of allyl-modified tert-octyl phenolic resin and 2 parts of p-dinitrosobenzene, add them to the reactor, stir and disperse; add 3 parts of carbon black into the reactor in three times, stir and disperse, and discharge the top coating adhesive 5, which contains 24wt% of allyl-modified tert-octyl phenolic resin.

[0036] Comparative Example

[0037] Preparation of primer-type adhesive: weigh 60 parts of methyl isobutyl ketone and 10 parts of kneaded chloroprene rubber, add them into a reactor, and stir until they are completely dissolved; weigh 8 parts of titanium dioxide, 2 parts of zinc oxide, 5 parts of phenolic resin 204A, 5 parts of carbon black, and 10 parts of γ-mercaptopropyltrimethoxysilane, add them into the reactor in sequence, stir, disperse evenly, and discharge to obtain a primer-type adhesive (comparison);

[0038] Preparation of surface coating adhesive: weigh 70 parts of xylene and 8 parts of kneaded chlorosulfonated polyethylene rubber into a reactor and stir until completely dissolved; weigh 10 parts of phenolic resin 204A and 4 parts of p-dinitrosobenzene into a reactor and stir and disperse; add 8 parts of carbon black into the reactor in three times and stir and disperse to obtain a surface coating adhesive (comparison).

[0039] Performance Testing

[0040] The rubber used in the test of the present invention is EPDM rubber, and the metal is stainless steel. The preparation method of the test piece is to brush the evenly stirred primer adhesive on the stainless steel surface that has been sandblasted and wiped with toluene, and brush it for a second time after drying for 10 minutes, and brush the top coating adhesive on the primer, dry it naturally for 2 hours, put it in an oven at 80°C to dry for 10 minutes, and then vulcanize it at 160°C, the vulcanization time is 2 hours, and the vulcanization pressure is 5MPa. The total coating thickness is 10u, and after hot vulcanization bonding, it is tested according to the GB / 11211-1989 method for determining the bonding strength of vulcanized rubber and metal (tear strength) and the GB / T15254-1994 180° peel test (peel strength) of vulcanized rubber and metal bonding.

[0041] The adhesion test is judged according to the type of specimen failure: R-rubber failure; RC-interface failure between rubber and adhesive bonding layer; CP-interface failure between adhesive bonding layer and primer layer; CM-interface failure between adhesive layer and metal substrate; D-adhesive-free specimen, direct interface failure between rubber and metal substrate; M-metal substrate failure.

[0042] Table 1 Performance comparison of double-coated rubber-metal hot-vulcanized adhesives

[0043]

[0044]

[0045] From the data analysis in Table 1, it can be seen that embodiments 1-5 use allyl-modified tert-octyl phenolic resin as tackifying resin added to the primer adhesive and the top-coating adhesive, while the comparative example uses ordinary unmodified phenolic resin as tackifying resin added to the primer adhesive and the top-coating adhesive. The test data show that the mechanical properties of embodiments 1-5 of the present invention are significantly better than the comparative example, and the interface damage of embodiments 1-5 is rubber damage, while the comparative example is the interface damage between the adhesive bonding layer and the primer layer. The results show that the addition of allyl-modified tert-octyl phenolic resin improves the bonding strength of the metal and rubber interface, especially improves the interface bonding strength between the primer adhesive and the top-coating adhesive, indicating that the addition of allyl-modified tert-octyl phenolic resin enhances the interaction force of the two adhesives, that is, the cohesive force between the adhesives is enhanced. In addition, in Examples 1-5 of the present invention, as the mass proportion of allyl-modified tert-octylphenolic resin in the primer adhesive and the top-coating adhesive increases from low to high, the bonding strength also changes accordingly. When the content of allyl-modified tert-octylphenolic resin is low, the bonding strength is not significantly improved. When the weight ratio of allyl-modified tert-octylphenolic resin in the primer adhesive is controlled to be 5%-10%, and the weight ratio of allyl-modified tert-octylphenolic resin in the top-coating adhesive is 10%-20%, the two adhesives are matched with double coating to achieve the best bonding performance. Within this ratio range, the effect of allyl-modified tert-octylphenolic resin enables the interaction between the top-coating adhesive and the rubber, and the top-coating adhesive and the primer adhesive to reach the best balance.

[0046] The above-mentioned embodiments of the present invention are intended to illustrate the best implementation methods for the situation, but the protection scope of the present invention is not limited thereto. For any technical personnel familiar with the technical field, any changes or substitutions that can be easily thought of within the technical scope disclosed by the present invention, as well as any changes should be covered within the protection scope of the present invention.

Claims

1. A rubber-metal hot-vulcanization bonding double-coating adhesive, characterized in that: The invention comprises a primer-coating adhesive and a surface-coating adhesive, wherein the primer-coating adhesive is composed of 5-10 parts of halogenated rubber, 5-10 parts of tackifying resin, 5-10 parts of coupling agent, 0.1-5 parts of dye, 1-8 parts of filler and 50-60 parts of solvent in parts by weight; the surface-coating adhesive is composed of 5-20 parts of halogenated rubber, 10-20 parts of tackifying resin, 1-10 parts of adhesion promoter, 1-10 parts of dye and 65-125 parts of solvent in parts by weight; wherein the halogenated rubber in the primer-coating adhesive is chloroprene. The invention relates to a method for preparing the allyl-modified tert-octylphenol-formaldehyde resin, wherein the tackifying resin in the primer adhesive and the top-coat adhesive is an allyl-modified tert-octylphenol-formaldehyde resin, and the weight ratio of the allyl-modified tert-octylphenol-formaldehyde resin in the primer adhesive is controlled to be 5%-10%, and the weight ratio of the allyl-modified tert-octylphenol-formaldehyde resin in the top-coat adhesive is controlled to be 10%-20%. The method for preparing the allyl-modified tert-octylphenol-formaldehyde resin comprises: (1) weighing tert-octylphenol and concentrated sulfuric acid in a four-necked bottle, placing a stirring paddle, a condenser and a stirring rod; tube and thermometer, apply vacuum grease on the ground joint to maintain the sealing of the system, and then put it into a preheated 140℃ oil bath pot, heat to melt tert-octylphenol; (2) weigh acetaldehyde and transfer it to a constant pressure dropping funnel. When tert-octylphenol is completely melted and the system temperature is 100-120℃, start to slowly add acetaldehyde solution dropwise for 3-5h. The system temperature is 90-130℃ during the addition; (3) After the acetaldehyde is added, continue to react for 1-2h, then slowly add acrolein. After the acrolein is added, react for 2-3h, then stop the reaction; (4) use methyl alcohol to add acetaldehyde. The mixture after the benzene dissolution reaction is prepared, and the amount of sodium hydroxide required is calculated according to the amount of acid, and an aqueous solution is prepared, which is added to the toluene solution and stirred to mix well. After the aqueous phase is separated, the aqueous phase is washed twice with neutral water to separate the aqueous phase, and the organic phase is retained; (5) the organic phase is rotary evaporated at a rotary evaporation temperature of 120° C. until no liquid is distilled out, and vacuum dried at 200° C. for 2 hours to obtain an allyl-modified tert-octylphenol-formaldehyde resin, wherein the molar ratio of tert-octylphenol to acetaldehyde is 1:0.7-1:0.95, acrolein accounts for 5-20wt% of the tert-octylphenol, and concentrated sulfuric acid accounts for 5-10wt%.

2. The rubber-metal hot-vulcanization bonding double-coating adhesive according to claim 1, characterized in that The coupling agent in the primer-coating adhesive is one of γ-mercaptopropyltrimethoxysilane, propyl methacrylate trimethoxysilane, vinyl trimethoxysilane, and γ-glycidyloxypropyltrimethoxysilane; the dye in the primer-coating adhesive is carbon black; the filler in the primer-coating adhesive is one of titanium dioxide and zinc oxide or a combination of two; the solvent in the primer-coating adhesive is one of acetone, butanone, and methyl isobutyl ketone.

3. The rubber-metal hot-vulcanization bonding double-coating adhesive according to claim 1, characterized in that The halogenated rubber in the surface-coated adhesive is one of chlorosulfonated polyethylene rubber and chlorinated polyethylene rubber; the adhesion promoter in the surface-coated adhesive is a polynitroso aromatic compound; the dye in the surface-coated adhesive is carbon black; the solvent in the surface-coated adhesive is one of toluene, xylene, ethyl acetate, butyl acetate, and dimethyl carbonate, or a combination of several thereof.

4. The method for preparing a rubber-metal hot-vulcanization bonding double-coating adhesive as claimed in claim 1, characterized in that The following steps are involved: (1) Preparing a primer-coating adhesive: weighing 50-60 parts of a solvent and 5-10 parts of a kneaded halogenated rubber, adding them to a reactor, and stirring until they are completely dissolved; weighing 1-8 parts of a filler, 5-10 parts of a tackifying resin, 0.1-5 parts of a dye, and 5-10 parts of a coupling agent, sequentially adding them to a reactor, stirring, and dispersing them uniformly, and discharging the materials to obtain a primer-coating adhesive; (2) Preparation of a top-coating adhesive: Weigh 65-125 parts of a solvent and 5-20 parts of a kneaded halogenated rubber, add them to a reactor, and stir until they are completely dissolved; weigh 10-20 parts of a tackifying resin and 1-10 parts of an adhesion promoter, add them to a reactor, stir, and disperse; add 1-10 parts of a dye three times, add them to the reactor, stir, and disperse, and discharge to obtain a top-coating adhesive.

5. The method for using the rubber-metal hot-vulcanization bonding double-coating adhesive as claimed in claim 1, characterized in that The following steps are involved: (1) Stir both the primer and topcoat adhesives for 30 minutes before use; (2) After sandblasting the metal surface to be bonded, wipe it with a cotton cloth dipped in alcohol, toluene or xylene and let it dry naturally for 3-5 minutes; (3) Apply the stirred primer adhesive to the metal surface and apply a second coat after it has dried for a few minutes; (4) Apply the topcoat adhesive on the primer, dry it naturally for 1-2 hours, put it in an oven at 80°C for 10 minutes, and then hot-press vulcanize it at 150-170°C.

6. An application of the rubber-metal hot-vulcanization bonding double-coating adhesive as claimed in claim 1, characterized in that: The double-coating adhesive is suitable for hot vulcanization bonding of rubber and metal, wherein the rubber includes chloroprene rubber, nitrile rubber, styrene-butadiene rubber, butyl rubber, butadiene rubber, and ethylene-propylene rubber; and the metal includes cast iron, carbon steel, stainless steel, alloy steel, aluminum, aluminum alloy, copper, and copper alloy.

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