Adhesive film material for bonding metal and pure ethylene propylene diene monomer-based heat insulation layer and preparation method of adhesive film material
By introducing ε-caprolactam-capsuled isocyanate compounds between metal and pure ethylene propylene rubber, a second crosslinking network is constructed, and the problem of bonding between metal and pure ethylene propylene rubber in the prior art is solved, and an efficient and environmentally friendly bonding effect is achieved.
Patent Information
- Application Number
- CN202411926828.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-03-11
AI Technical Summary
The prior art is difficult to achieve the bonding between metals with high bond strength and pure EPDM rubber, and common adhesives have problems with poor storage stability and high toxicity.
Using a film material without primer, a second crosslinking network is constructed by introducing ε-caprolactam-capsuled isocyanate compounds into the formulation to achieve direct bonding between metal and pure ethylene propylene ternary rubber.
Simplifies the bonding process, reduces costs, improves bonding reliability, and is solvent-free, healthy and environmentally friendly.
Smart Images
Figure CN119592251A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of adhesive materials, and in particular to an adhesive film material for bonding metal to a pure EPDM rubber-based thermal insulation layer and a preparation method thereof. Background Art
[0002] EPDM rubber has excellent heat resistance, weather resistance and filling performance. It also has the advantages of low density, good impact resistance and good low-temperature flexibility. It has been widely used in the fields of automobiles, aviation, aerospace, etc. It is particularly noteworthy that in the thermal insulation layer of the combustion chamber of solid rocket engines, EPDM non-polar rubber is a widely used basic material. The interface between the EPDM thermal insulation layer and the shell, as well as the interface between EPDM rubber and EPDM rubber, need to be bonded and fixed by adhesives, but the molecular structure of EPDM rubber is a saturated straight chain structure without double bonds. This molecular structure makes EPDM rubber have poor self-adhesion and mutual adhesion with other materials. In particular, when bonding EPDM rubber and metal with different physical and chemical properties, it is particularly difficult to obtain high bonding strength.
[0003] In order to solve the problem of bonding EPDM rubber to metal, the prior art mostly adopts the method of first coating the metal surface with a primer to form a bonding transition layer, and then coating the adhesive on the transition layer surface to achieve the purpose of bonding. This method has a cumbersome process, high cost, and poor bonding reliability. Secondly, there is also a method of improving the bonding strength of products by using polar rubbers such as nitrile rubber in EPDM rubber. However, while the bonding performance is improved, it will bring negative effects such as decreased aging resistance and increased density to the products. In addition, the free isocyanate groups in the lekna glue with triphenylmethane triisocyanate as the main active ingredient are easy to react with moisture, so the storage stability is poor, and the chlorobenzene solvent used is highly toxic; the adhesive with 3-aminopropyl triethoxysilane-terminated polyisocyanate compound as the main component developed by Shanghai Rubber Products Research Institute Co., Ltd. contains silane that is easy to hydrolyze, and there will also be a problem of poor storage stability, and the xylene solvent used is also toxic; the above two adhesives are harmful to the health of operators during use. Therefore, it is of great application value to develop a solvent-free adhesive material for bonding metal to pure EPDM rubber-based insulation layer that has excellent bonding properties, does not require a primer, and is healthy and environmentally friendly. Summary of the invention
[0004] In view of the deficiencies in the above-mentioned background technology, the present invention provides a film material for bonding metal to pure EPDM rubber-based insulation layer and a preparation method thereof. The present invention mainly provides a film material for bonding metal to pure EPDM rubber-based insulation layer without primer, especially on the basis of the cross-linking network provided by the vulcanizer in the formula, further introducing an ε-caprolactam-terminated isocyanate compound in the formula, thereby constructing a second cross-linking network between the metal and the pure EPDM rubber insulation layer, thereby achieving the purpose of direct bonding between the metal and the pure EPDM rubber without primer transition.
[0005] The first object of the present invention is to provide a film material for bonding metal to a pure EPDM rubber-based insulation layer. The raw materials of the film material include the following components in parts by weight: 100 parts of a matrix polymer, 5 to 30 parts of a tackifying resin, 3 to 10 parts of a functional filler, 1 to 5 parts of a reinforcing filler, 1 to 15 parts of a vulcanizing agent, 1 to 20 parts of a special cross-linking agent, and 50 to 100 parts of a solvent; The matrix polymer is one or more of chlorinated EPDM rubber, brominated EPDM rubber, chlorinated polyethylene, chlorosulfonated polyethylene, chlorinated polypropylene or chlorosulfonated polypropylene; The functional filler is zinc oxide and / or magnesium oxide; The reinforcing filler is one or more of mica, carbon black, silicon dioxide and calcium carbonate; The special cross-linking agent is an ε-caprolactam-terminated isocyanate compound.
[0006] Preferably, the tackifying resin is one or more of terpene resin, terpene phenolic resin, C5 petroleum resin, C9 petroleum resin, and rosin resin.
[0007] Preferably, the ε-caprolactam-blocked isocyanate compound is one or more of ε-caprolactam-blocked tetramethyl dimethylene diisocyanate, ε-caprolactam-blocked 4,4'-diphenylmethane diisocyanate, ε-caprolactam-blocked toluene diisocyanate, ε-caprolactam-blocked hexamethylene diisocyanate, and ε-caprolactam-blocked triphenylmethane triisocyanate.
[0008] Preferably, the ε-caprolactam blocked isocyanate compound is prepared according to the following steps: Step 1: adding half of the prescribed amount of dibutyltin dilaurate catalyst to a xylene solution of ε-caprolactam having a mass fraction of 10% to 80%; Step 2: add the isocyanate compound to the solution of step 1, and then add the other half of the dibutyltin dilaurate catalyst, and then keep the reaction at 60-80°C for 3-8h, and keep stirring during the process at a speed of 200-300rpm; Step 3: After the reaction system of step 2 is cooled to room temperature, it is poured into a certain amount of ether to precipitate the product, the material is filtered out, and the filter cake is dried at 10-60° C. to obtain an ε-caprolactam-terminated isocyanate compound.
[0009] Preferably, the ε-caprolactam xylene solution is prepared by dissolving ε-caprolactam in xylene; The molar amount of the ε-caprolactam is 1.05 to 1.1 times the molar amount of the isocyanate group in the isocyanate compound; the total amount of the dibutyltin dilaurate catalyst added accounts for 0.5% to 3.5% of the mass percentage of the isocyanate compound.
[0010] Preferably, the isocyanate compound is one or more of tetramethyl dimethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and triphenylmethane triisocyanate.
[0011] Preferably, the vulcanizing agent is one or more of p-benzoquinone, p-benzoquinone dioxime, nitrosobenzene, o-dinitrosobenzene, p-nitrosotoluene, p-dinitrosobenzene and m-dinitrosobenzene.
[0012] Preferably, the solvent is one or more of xylene, cyclohexane, and methyl isobutyl ketone.
[0013] The second object of the present invention is to provide a method for preparing a film material for bonding metal to a pure EPDM rubber-based insulation layer, comprising the following steps: Weigh the raw materials according to the following weight proportions: 100 parts of base polymer, 5-30 parts of tackifying resin, 3-10 parts of functional filler, 1-5 parts of reinforcing filler, 1-15 parts of vulcanizing agent, 1-20 parts of special cross-linking agent, and 50-100 parts of solvent; The raw materials are ground and mixed into a uniform viscous dispersion, and then coated to obtain a film material.
[0014] The third object of the present invention is to provide an application of an adhesive film material in bonding metal to rubber.
[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a film material for bonding metal to pure EPDM rubber-based thermal insulation layer and a preparation method thereof. The special crosslinking agent used in the present invention is an ε-caprolactam-terminated isocyanate compound. During the bonding vulcanization process, the blocked isocyanate group will be released when the unblocking temperature is reached. The free isocyanate group can react chemically with the hydroxyl group on the surface of the bonded metal. At the same time, the isocyanate group will also react with the active groups on the surface of the tackifying resin and inorganic filler in the thermal insulation layer material, thereby enhancing the bonding strength.
[0016] Compared with traditional liquid adhesives, the adhesive film material provided by the present invention does not require primer coating, has a simple bonding process, and is more cost-effective, effectively solving the problem that pure EPDM rubber and metal cannot be directly bonded with adhesives; secondly, it eliminates the adverse effects on the aging resistance and density of the product caused by increasing the bonding performance by using polar rubber; in addition, no organic solvent volatilizes during use, which is friendly to human health and the environment.
[0017] The functional filler in the present invention acts as a cross-linking agent for the matrix polymer, and during the heating process, the matrix polymer is cross-linked into a network structure, thereby improving the bonding strength of the film; the reinforcing filler can effectively disperse external stress, increase the bonding strength, and also improve the heat resistance of the film; the vulcanizing agent can participate in the vulcanization reaction of the EPDM rubber, and form a chemical bond between the film and the EPDM rubber. In addition, it can also react chemically with the metal, thereby forming a chemical action between the metal and the EPDM rubber, and play a role in bonding the metal and the EPDM rubber; the blocked isocyanate group of the isocyanate compound blocked by the special vulcanizing agent ε-caprolactam will be released when the unblocking temperature is reached during the bonding vulcanization process, and the released isocyanate group can react chemically with the hydroxyl group on the surface of the bonded metal, and at the same time, the isocyanate group will also react with the active group on the surface of the tackifying resin and the inorganic filler in the insulation layer material, thereby playing a role in enhancing the bonding strength. It can be seen that the synergistic effect between the components of the raw materials can achieve a strong bonding effect between the steel and the EPDM rubber insulation layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is the temperature-varying infrared spectrum of ε-caprolactam-terminated triphenylmethane triisocyanate.
[0019] Figure 2 This is a physical picture of the film material prepared in Example 4. DETAILED DESCRIPTION
[0020] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments, but the embodiments are not intended to limit the present invention.
[0021] The purpose of the present invention is to achieve direct bonding between metal and pure EPDM rubber without primer transition. The present invention provides a method for preparing a film material for bonding pure EPDM rubber and metal without primer transition, in particular, on the basis of the cross-linking network provided by the vulcanizer in the formula, further introducing an ε-caprolactam-terminated isocyanate compound in the formula, thereby constructing a second cross-linking network between the metal and the EPDM rubber, thereby achieving the purpose of direct bonding between the metal and the pure EPDM rubber without primer transition.
[0022] In order to achieve the above-mentioned object, the first aspect of the present invention provides a film material for bonding metal to a pure EPDM rubber-based insulation layer, wherein the raw materials of the film material include the following components in parts by weight: 100 parts of a matrix polymer, 5 to 30 parts of a tackifying resin, 3 to 10 parts of a functional filler, 1 to 5 parts of a reinforcing filler, 1 to 15 parts of a vulcanizing agent, 1 to 20 parts of a special cross-linking agent, and 50 to 100 parts of a solvent; The matrix polymer is one or more of chlorinated EPDM rubber, brominated EPDM rubber, chlorinated polyethylene, chlorosulfonated polyethylene, chlorinated polypropylene or chlorosulfonated polypropylene; The functional filler is zinc oxide and / or magnesium oxide; The reinforcing filler is one or more of mica, carbon black, silicon dioxide and calcium carbonate; The special cross-linking agent is an ε-caprolactam-terminated isocyanate compound.
[0023] The tackifying resin is one or more of terpene resin, terpene phenolic resin, C5 petroleum resin, C9 petroleum resin and rosin resin.
[0024] The solvent is one or more of xylene, cyclohexane and methyl isobutyl ketone.
[0025] The vulcanizing agent is one or more of p-benzoquinone, p-benzoquinone dioxime, nitrosobenzene, o-dinitrosobenzene, p-nitrosotoluene, p-dinitrosobenzene and m-dinitrosobenzene.
[0026] The ε-caprolactam-terminated isocyanate compound is one or more of ε-caprolactam-terminated tetramethyl dimethylene diisocyanate, ε-caprolactam-terminated 4,4'-diphenylmethane diisocyanate, ε-caprolactam-terminated toluene diisocyanate, ε-caprolactam-terminated hexamethylene diisocyanate, and ε-caprolactam-terminated triphenylmethane triisocyanate.
[0027] The ε-caprolactam-terminated isocyanate compound is prepared according to the following steps: Step 1: adding half of the prescribed amount of dibutyltin dilaurate catalyst to a xylene solution of ε-caprolactam having a mass fraction of 10% to 80%; Step 2: Add the isocyanate compound (solution) to the solution of step 1, and then add the other half of the dibutyltin dilaurate catalyst, and then keep the reaction at 60-80°C for 3-8h, and keep stirring during this process at a speed of 200-300rpm; Step 3: After the reaction system of step 2 is cooled to room temperature, it is poured into a certain amount of ether to precipitate the product, the material is filtered out, and the filter cake is dried at 10-60° C. to obtain an ε-caprolactam-terminated isocyanate compound.
[0028] The ε-caprolactam xylene solution is prepared by dissolving ε-caprolactam in xylene; The molar amount of the ε-caprolactam is 1.05 to 1.1 times the molar amount of the isocyanate group in the isocyanate compound; the total amount of the dibutyltin dilaurate catalyst added accounts for 0.5% to 3.5% of the mass percentage of the isocyanate compound.
[0029] The isocyanate compound is one or more of tetramethyl dimethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and triphenylmethane triisocyanate.
[0030] It should be noted that the purpose of the ε-caprolactam blocked isocyanate compound is that the blocked isocyanate group will be released when the deblocking temperature is reached during the bonding vulcanization process, and the released isocyanate group can chemically react with the hydroxyl group on the surface of the bonded metal, and the released isocyanate group will also react with the active groups on the surface of the tackifying resin and inorganic filler in the insulation layer material, thereby enhancing the bonding strength.
[0031] The special cross-linking agent used in the present invention refers to an ε-caprolactam-terminated isocyanate compound, which can be unblocked and release isocyanate groups during the heating and vulcanization process, thereby building a second cross-linking network between the metal and the EPDM rubber on the basis of the cross-linking network provided by the vulcanizing agent in the formula, thereby achieving the purpose of direct bonding between the metal and the pure EPDM rubber-based insulation layer without the need for a primer transition.
[0032] The second aspect of the present invention provides a method for preparing a film material for bonding metal to a pure EPDM rubber-based insulation layer, comprising the following steps: Weigh the raw materials according to the following weight proportions: 100 parts of base polymer, 5-30 parts of tackifying resin, 3-10 parts of functional filler, 1-5 parts of reinforcing filler, 1-15 parts of vulcanizing agent, 1-20 parts of special cross-linking agent, and 50-100 parts of solvent; The raw materials are ground and mixed into a uniform viscous dispersion, and then coated to obtain a film material.
[0033] A third aspect of the present invention provides an application of an adhesive film material in bonding metal to rubber.
[0034] It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used are all commercially available unless otherwise specified.
[0035] 1. Synthesis of ε-caprolactam blocked isocyanate compounds Example 1 2.1 mol of ε-caprolactam was prepared into a xylene solution with a mass fraction of 50%, and then added to a dry three-necked flask, and then 0.87 g of dibutyltin dilaurate was added thereto, and the temperature was raised to 65°C, and 1 mol of toluene diisocyanate was added to the system through a constant pressure dropping funnel under magnetic stirring at 200 rpm. The addition was completed in about 30 minutes, and then 0.87 g of dibutyltin dilaurate was added thereto, and the reaction was kept at 65°C for 5 hours. After the reaction was completed, it was cooled to room temperature, poured into 1000 mL of ether, the product was filtered out, and the filter cake was dried at 50°C to obtain ε-caprolactam-terminated 2,4'-toluene diisocyanate.
[0036] Example 2 1.65 mol of ε-caprolactam was prepared into a xylene solution with a mass fraction of 35%, and then added to a dry three-necked flask, and then 0.55 g of dibutyltin dilaurate was added thereto, and the temperature was raised to 75°C. Under the condition of magnetic stirring at 200 rpm, 0.5 mol of triphenylmethane triisocyanate was added dropwise to the system through a constant pressure dropping funnel. The addition was completed in about 30 minutes, and then 0.55 g of dibutyltin dilaurate was added thereto. The reaction was kept at 75°C for 6 hours. After the reaction was completed, it was cooled to room temperature, poured into 1100 mL of ether, the product was filtered out, and the filter cake was dried at 55°C to obtain ε-caprolactam-terminated triphenylmethane triisocyanate.
[0037] See also Figure 1 As shown, the temperature-varying infrared spectrum of ε-caprolactam-capped triphenylmethane triisocyanate. It can be seen from the temperature-varying infrared spectrum of ε-caprolactam-capped triphenylmethane triisocyanate that at room temperature, ε-caprolactam-capped triphenylmethane triisocyanate is in a closed state without free isocyanate groups; when the temperature rises to above 150°C, the ε-caprolactam-capped triphenylmethane triisocyanate is unblocked and the isocyanate groups are released.
[0038] Example 3 1.06 mol of ε-caprolactam was prepared into a xylene solution with a mass fraction of 60%, and then added to a dry three-necked flask, and then 0.93 g of dibutyltin dilaurate was added thereto, and the temperature was raised to 60°C. Under the condition of magnetic stirring at 200 rpm, 0.5 mol of 4,4'-diphenylmethane diisocyanate was added to the system through a constant pressure dropping funnel. The addition was completed in about 30 minutes, and then 0.93 g of dibutyltin dilaurate was added thereto. The reaction was kept at 60°C for 8 hours. After the reaction was completed, it was cooled to room temperature, poured into 1500 mL of ether, the product was filtered out, and the filter cake was dried at 50°C to obtain ε-caprolactam-terminated 4,4'-diphenylmethane diisocyanate.
[0039] 2. Preparation of film Example 4 100 g of chlorosulfonated polypropylene, 10 g of terpene phenolic resin, 3 g of magnesium oxide, 5 g of silicon dioxide, 3 g of p-benzoquinone dioxime, 6 g of ε-caprolactam-terminated triphenylmethane triisocyanate, 25 g of xylene and 50 g of methyl isobutyl ketone were weighed respectively, and then the above raw materials were ground in a sand mill at a speed of 1500 rpm for 30 min to obtain a viscous liquid, which was then coated to prepare a film material, see Figure 2 As shown, a film-like material is prepared in this embodiment. During use, the film-like material is cut into a desired shape and then placed between metal and rubber, and the bonding of the metal and rubber is achieved by heating.
[0040] Example 5 100 g of chlorinated polypropylene, 20 g of C5 petroleum resin, 5 g of zinc oxide, 3 g of mica, 6 g of p-benzoquinone dioxime, 8 g of ε-caprolactam-terminated 4,4'-diphenylmethane diisocyanate, 75 g of xylene and 25 g of methyl isobutyl ketone were weighed respectively, and then the above raw materials were ground in a sand mill at 3000 rpm for 15 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0041] Example 6 100 g of ethylene propylene diene chloride, 25 g of terpene resin, 3 g of zinc oxide, 3 g of carbon black, 2 g of silica, 8 g of o-dinitrosobenzene, 15 g of ε-caprolactam-terminated triphenylmethane triisocyanate, 80 g of xylene, and 20 g of cyclohexane were weighed respectively, and then the above raw materials were ground in a colloid mill at a speed of 2500 rpm for 30 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0042] Example 7 100 g of chlorinated polyethylene, 15 g of rosin resin, 6 g of magnesium oxide, 5 g of silicon dioxide, 5 g of nitrosobenzene, 10 g of ε-caprolactam-terminated triphenylmethane triisocyanate, and 80 g of xylene were weighed respectively, and then the above raw materials were ground in a colloid mill at a speed of 2000 rpm for 30 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0043] Example 8 50 g of chlorinated polyethylene, 50 g of ethylene propylene diene chloride, 15 g of terpene phenolic resin, 7 g of zinc oxide, 3 g of silica, 5 g of nitrosobenzene, 2 g of p-benzoquinone dioxime, 16 g of ε-caprolactam-terminated triphenylmethane triisocyanate, and 100 g of xylene were weighed respectively, and then the above raw materials were ground in a colloid mill at a speed of 2000 rpm for 30 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0044] Example 9 100 g of chlorinated polyethylene, 15 g of rosin resin, 5 g of C9 petroleum resin, 5 g of zinc oxide, 2 g of silica, 1 g of calcium carbonate, 10 g of p-benzoquinone dioxime, 8 g of ε-caprolactam-terminated 2,4'-toluene diisocyanate, 50 g of xylene, and 30 g of cyclohexane were weighed respectively, and then the above raw materials were ground in a colloid mill at a speed of 3000 rpm for 15 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0045] Comparative Example 1 100 g of chlorosulfonated polypropylene, 10 g of terpene phenolic resin, 3 g of magnesium oxide, 5 g of silicon dioxide, 3 g of p-benzoquinone dioxime, 25 g of xylene and 50 g of methyl isobutyl ketone were weighed respectively, and then the above raw materials were ground in a sand mill at a speed of 1500 rpm for 30 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0046] Comparative Example 2 100 g of ethylene propylene diene chloride, 25 g of terpene resin, 3 g of zinc oxide, 3 g of carbon black, 2 g of silica, 8 g of o-dinitrosobenzene, 80 g of xylene, and 20 g of cyclohexane were weighed respectively, and then the above raw materials were ground in a colloid mill at a speed of 2500 rpm for 30 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0047] Comparative Example 3 100 g of chlorinated polyethylene, 15 g of rosin resin, 5 g of C9 petroleum resin, 5 g of zinc oxide, 2 g of silicon dioxide, 1 g of calcium carbonate, 10 g of p-benzoquinone dioxime, 50 g of xylene, and 30 g of cyclohexane were weighed respectively, and then the above raw materials were ground in a colloid mill at a speed of 3000 rpm for 15 min to obtain a viscous liquid, which was then coated to prepare a film material.
[0048] 3. Performance Test The bonding performance is evaluated by testing the tensile and shear specimens of 45# steel and pure EPDM rubber-based insulation layer bonded by the adhesive film of the present invention. The tensile strength of 45# steel-pure EPDM rubber-based insulation layer is prepared and tested according to GB / T 11211-2019 standard, and the shear strength of 45# steel-pure EPDM rubber-based insulation layer is prepared and tested according to GB / T 13936-2014 standard. The specific steps of preparing the specimen are as follows: (1) 45# steel should be sandblasted within 8 hours before bonding, and its surface should be cleaned with ethyl acetate and then dried for use. The pure EPDM rubber-based insulation layer should be cleaned with ethyl acetate and then dried for use before use; (2) laying a layer of adhesive film between the interface of the 45# steel and the rubber bonding area of the pure EPDM rubber-based insulation layer after being cleaned and dried in step (1), and then butting and pasting them; (3) Place the sample after butt bonding in step (2) into a metal mold and vulcanize it at a temperature of 160°C and a pressure of 10 MPa for 1.5 h.
[0049] The test results are shown in Table 1 below.
[0050] Table 1 shows the tensile and shear performance data of 45# steel and pure EPDM rubber-based insulation layer bonded by adhesives provided in Examples 4 to 9 and Comparative Examples 1 to 3.
[0051]
[0052] From the test results in Table 1, it can be seen that the adhesive performance of the adhesive film material containing the ε-caprolactam-terminated isocyanate compound component is significantly better than that of the adhesive film material without this component. This is because the adhesive effect of the adhesive film in the comparative example mainly relies on the chemical crosslinking generated by the vulcanizer between the rubber and the metal, and the physical interaction force generated by other components at the interface; however, the adhesive effect of the adhesive film in the embodiment not only has the chemical crosslinking generated by the vulcanizer between the rubber and the metal, and the physical interaction force generated by other components at the interface, but more importantly, the ε-caprolactam-terminated isocyanate compound will be unblocked under high-temperature vulcanization conditions to release free isocyanate groups, and the isocyanate groups will chemically crosslink with the hydroxyl groups on the metal surface and other active groups in the insulation layer to establish a second crosslinking network, thereby enhancing the bonding strength.
[0053] In summary, the present invention relates to a method for preparing a film material for bonding the shell metal and the pure EPDM rubber-based insulation layer without primer in the manufacturing process of the internal insulation system of a solid rocket engine. 100 parts of matrix polymer, 5 to 30 parts of tackifying resin, 3 to 10 parts of functional filler, 1 to 5 parts of reinforcing filler, 1 to 15 parts of vulcanizing agent, 1 to 20 parts of special cross-linking agent and 50 to 100 parts of solvent are ground and mixed evenly to obtain a uniform viscous dispersion, and then coated to prepare the film material. The special cross-linking agent refers to an ε-caprolactam-terminated isocyanate compound, which can be unblocked and release isocyanate groups during the heating and vulcanization process, so that on the basis of the cross-linking network provided by the vulcanizing agent in the formula, a second cross-linking network is constructed between the metal and the pure EPDM rubber-based insulation layer, so as to achieve the purpose of direct bonding between the metal and the pure EPDM rubber-based insulation layer without the transition of a primer. This method simplifies the bonding process, reduces bonding costs, and improves bonding reliability; moreover, there is no solvent volatilization during use, which is healthy and environmentally friendly.
[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A film material for bonding metal to pure EPDM rubber-based insulation layer, characterized in that: The raw materials of the adhesive film material include the following components in parts by weight: 100 parts of base polymer, 5-30 parts of tackifying resin, 3-10 parts of functional filler, 1-5 parts of reinforcing filler, 1-15 parts of vulcanizing agent, 1-20 parts of special cross-linking agent, and 50-100 parts of solvent; The matrix polymer is one or more of chlorinated EPDM rubber, brominated EPDM rubber, chlorinated polyethylene, chlorosulfonated polyethylene, chlorinated polypropylene or chlorosulfonated polypropylene; The functional filler is zinc oxide and / or magnesium oxide; The reinforcing filler is one or more of mica, carbon black, silicon dioxide and calcium carbonate; The special cross-linking agent is an ε-caprolactam-terminated isocyanate compound.
2. The adhesive film material for bonding metal to pure EPDM rubber-based insulation layer according to claim 1, characterized in that: The tackifying resin is one or more of terpene resin, terpene phenolic resin, C5 petroleum resin, C9 petroleum resin and rosin resin.
3. The adhesive film material for bonding metal to pure EPDM rubber-based insulation layer according to claim 1, characterized in that: The ε-caprolactam-terminated isocyanate compound is one or more of ε-caprolactam-terminated tetramethyl dimethylene diisocyanate, ε-caprolactam-terminated 4,4'-diphenylmethane diisocyanate, ε-caprolactam-terminated toluene diisocyanate, ε-caprolactam-terminated hexamethylene diisocyanate, and ε-caprolactam-terminated triphenylmethane triisocyanate.
4. The adhesive film material for bonding metal to pure EPDM rubber-based insulation layer according to claim 3, characterized in that: The ε-caprolactam-terminated isocyanate compound is prepared according to the following steps: Step 1: adding a prescribed amount of half of dibutyltin dilaurate catalyst to a xylene solution of ε-caprolactam having a mass fraction of 10% to 80%; Step 2: add the isocyanate compound to the solution of step 1, and then add the other half of the dibutyltin dilaurate catalyst, and then keep the reaction at 60-80°C for 3-8h, and keep stirring during the process at a speed of 200-300rpm; Step 3: After the reaction system of step 2 is cooled to room temperature, it is poured into a certain amount of ether to precipitate the product, the material is filtered out, and the filter cake is dried at 10-60° C. to obtain an ε-caprolactam-terminated isocyanate compound.
5. The adhesive film material for bonding metal to pure EPDM rubber-based insulation layer according to claim 4, characterized in that: The ε-caprolactam xylene solution is prepared by dissolving ε-caprolactam in xylene; The molar amount of the ε-caprolactam is 1.05 to 1.1 times the molar amount of the isocyanate group in the isocyanate compound; the total amount of the dibutyltin dilaurate catalyst added accounts for 0.5% to 3.5% of the mass percentage of the isocyanate compound.
6. The adhesive film material for bonding metal to pure EPDM rubber-based insulation layer according to claim 4, characterized in that: The isocyanate compound is one or more of tetramethyl dimethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and triphenylmethane triisocyanate.
7. The adhesive film material for bonding metal to pure EPDM rubber-based insulation layer according to claim 1, characterized in that: The vulcanizing agent is one or more of p-benzoquinone, p-benzoquinone dioxime, nitrosobenzene, o-dinitrosobenzene, p-nitrosotoluene, p-dinitrosobenzene and m-dinitrosobenzene.
8. The adhesive film material for bonding metal to pure EPDM rubber-based insulation layer according to claim 1, characterized in that: The solvent is one or more of xylene, cyclohexane and methyl isobutyl ketone.
9. A method for preparing a film material for bonding metal to a pure EPDM rubber-based insulation layer according to any one of claims 1 to 8, characterized in that: The following steps are involved: Weigh the raw materials according to the following weight proportions: 100 parts of base polymer, 5-30 parts of tackifying resin, 3-10 parts of functional filler, 1-5 parts of reinforcing filler, 1-15 parts of vulcanizing agent, 1-20 parts of special cross-linking agent, and 50-100 parts of solvent; The raw materials are ground and mixed into a uniform viscous dispersion, and then coated to obtain a film material.
10. Use of the adhesive film material according to any one of claims 1 to 8 in bonding metal to rubber.