Black mastic material for hot welding of EPDM rubber strips and method for its production

Abstract

This invention discloses a black adhesive material for hot-melt bonding of EPDM rubber strips and its preparation method, belonging to the field of rubber product processing technology. The black adhesive material is obtained by mixing adhesive component A and adhesive component B diluted with gasoline. Adhesive component A includes EPDM rubber, paraffin oil, zinc oxide, stearic acid, PEG4000, dispersant, light calcium carbonate, and carbon black; adhesive component B includes sulfur and various vulcanization accelerators. During preparation, the components of adhesive component A are plasticized, mixed, and thin-passed to obtain component A. The vulcanization system is then mixed to obtain component B, which is diluted with gasoline and mixed with component A before use. When the adhesive material obtained by this invention is used for end splicing, corner connection, and hot-melt bonding of EPDM rubber strips, it can form a continuous and uniform black adhesive transition layer, improving joint peel strength, interface stability, aging resistance, and compression rebound retention.

Description

Technical Field

[0001] This invention relates to the field of rubber product processing technology, and in particular to a black adhesive material for hot-melt bonding of EPDM rubber strips and its preparation method. Background Technology

[0002] Ethylene propylene diene monomer (EPDM) rubber is an elastomer material copolymerized from ethylene, propylene, and a small amount of non-conjugated dienes as the main monomers. It possesses good weather resistance, ozone resistance, heat aging resistance, and sealing elasticity, and is widely used in automotive door and window sealing strips, building door and window sealing strips, cabinet sealing strips, equipment seals, and other rubber products requiring long-term compression sealing. In these applications, EPDM rubber strips typically need to be processed into frame-shaped, ring-shaped, or corner-connected sealing structures according to the product structure. Therefore, this inevitably involves processing steps such as end splicing, corner connection, and heat-melting into frames.

[0003] In the current process of hot-melt bonding EPDM rubber strips into frames, the ends of two rubber strips are usually cut to a predetermined angle or end face shape, and then butt-fitted together using a hot-melt bonding mold to form a connection at the joint under heat and pressure. However, EPDM rubber itself is a non-polar or low-polar rubber material with low surface activity, resulting in limited interfacial interaction with ordinary adhesives or conventional bonding systems. Furthermore, the end faces of EPDM rubber strips are prone to problems such as dust, exposed fillers, localized roughness, and uneven end-face adsorption after cutting. If splicing is done solely by hot pressing or ordinary adhesives, defects such as discontinuous adhesive layers, insufficient interfacial bonding, localized missing adhesive, bubbles, delamination, cracking, or significant color differences are likely to occur at the joint.

[0004] CN104194680A discloses a hot vulcanization joint adhesive for sealing strips, its preparation method, and its application. The adhesive is made of EPDM raw rubber, zinc oxide, stearic acid, carbon black, silica, processing oil, PEG4000, tackifying phenolic resin, sulfur, and various vulcanization accelerators. By using the adhesive at the joint of the EPDM sealing strip, the joint strength of the hot vulcanization joint of the sealing strip is improved, and the joint area is smaller, the joint is smoother, and the appearance is more aesthetically pleasing. CN103627093A discloses a method for improving the adhesion of EPDM rubber. This method involves modifying and mixing EPDM rubber with chlorinated butyl rubber and a mixing agent, then adding components such as zinc oxide, stearic acid, vulcanizing resin, silica, paraffin oil, rosin, C5 resin, vulcanizing agent, and adhesive to improve the heat-curing bonding adhesion of EPDM rubber. However, it cannot simultaneously solve the problems of continuity of the black transition layer at the joint, anchoring stability of the cut end face interface, uniformity of cross-linking of the thin vulcanized joint layer, peel strength retention rate after hot air aging, and rebound stability after wet heat compression during the hot-melt bonding of black EPDM rubber strips. Summary of the Invention

[0005] In view of the problems that existing technologies for EPDM rubber strips are prone to during hot-melt bonding, such as unstable joint interface bonding, insufficient continuity of the black transition layer, local delamination at the joint, decreased peel strength, and insufficient retention of adhesive performance after aging, the technical problem to be solved by the present invention is to provide a black adhesive material for hot-melt bonding of EPDM rubber strips and its preparation method, so that it can form a continuous, uniform black adhesive transition layer with good color consistency with the rubber strip body on the cut end face, splicing corner, or hot-melt frame connection area of ​​the EPDM rubber strip, and improve the interface bonding stability, peel resistance, aging resistance, and compression recovery stability of the hot-melt joint.

[0006] To achieve the above objectives, the present invention provides a black adhesive material for hot-melt bonding of EPDM rubber strips, comprising adhesive A and adhesive B diluted with gasoline; The adhesive A component comprises the following raw materials: EPDM rubber, paraffin oil, zinc oxide, stearic acid, PEG4000, dispersant, light calcium carbonate, carbon black, and modifier; the adhesive B component comprises the following raw materials: sulfur, zinc dibutyldithiocarbamate, zinc dimethyldithiocarbamate, 2-mercaptobenzothiazole, and N-cyclohexyl-2-benzothiazole sulfenamide.

[0007] Preferably, the adhesive A comprises the following raw materials in parts by weight: 35-45 parts EPDM rubber, 12-20 parts paraffin oil, 1.5-3.5 parts zinc oxide, 0.3-1 part stearic acid, 0.3-1 part PEG4000, 0.2-0.8 parts dispersant, 8-16 parts light calcium carbonate, 22-33 parts carbon black, and 0.8-2.5 parts modifier; The adhesive B component comprises the following raw materials in parts by weight: 0.7-1.3 parts sulfur, 0.2-0.7 parts zinc dibutyl dithiocarbamate, 0.08-0.3 parts zinc dimethyl dithiocarbamate, 0.2-0.7 parts 2-mercaptobenzothiazole, and 0.5-1.2 parts N-cyclohexyl-2-benzothiazole sulfenamide; The amount of gasoline added is 3-7 times the total mass of adhesive B.

[0008] The mass ratio of adhesive A to adhesive B is (25-50):1.

[0009] Preferably, the adhesive A material comprises the following raw materials in parts by weight: 37-42 parts of EPDM rubber, 14-18 parts of paraffin oil, 2.0-2.8 parts of zinc oxide, 0.45-0.75 parts of stearic acid, 0.45-0.75 parts of PEG4000, 0.30-0.5 parts of dispersant, 10-14 parts of light calcium carbonate, 25-30 parts of carbon black, and 1-1.8 parts of modifier.

[0010] Preferably, the adhesive B material comprises the following raw materials in parts by weight: 0.8-1.2 parts sulfur, 0.3-0.5 parts zinc dibutyldithiocarbamate, 0.1-0.2 parts zinc dimethyldithiocarbamate, 0.3-0.5 parts 2-mercaptobenzothiazole, and 0.6-1 parts N-cyclohexyl-2-benzothiazole sulfenamide.

[0011] Preferably, the mass ratio of adhesive A to adhesive B is (30-40):1.

[0012] The modifier is an interfacial crosslinking regulating component and / or an interfacial anchoring component. The interfacial crosslinking regulating component is at least one selected from 2,4,6-trimercapto-1,3,5-triazine, 2-mercapto-4,6-diamino-1,3,5-triazine, 2,4-dimercapto-6-amino-1,3,5-triazine, melamine, cyanuric acid, 2-mercaptopyrimidine, 2-mercaptopyridine, 2,5-dimercapto-1,3,4-thiadiazole, and thiourea; the interfacial anchoring component is at least one selected from catechol, hydroquinone, phenol, guaiacol, 2-methylphenol, gallic acid, and 1,2,3-phenylpyrogallol. Preferably, the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and catechol in a mass ratio of 1:(1-3). 2,4,6-Trithio-1,3,5-triazine can play a crosslinking assist role in the vulcanization system with its multi-thiol triazine structure, improving the crosslinking continuity of the thin-layer region of the heat-fused joint; the catechol has an ortho-bisphenol hydroxyl structure, which can enhance the interfacial interaction between the adhesive material and the cut end face of the EPDM rubber strip, zinc oxide, light calcium carbonate, and carbon black surface. The combination of these two components facilitates the formation of a continuous and stable composite interfacial transition layer at the joint, thereby improving the joint's peel resistance and aging retention performance.

[0013] The present invention also provides a method for preparing a black adhesive material for hot-melt bonding of EPDM rubber strips.

[0014] A method for preparing a black adhesive material for hot-melt bonding of EPDM rubber strips includes the following steps: Step 1: Put EPDM rubber into a mixer for plasticizing at a temperature of 60-80℃ for 3-8 minutes to form a uniform rubber matrix. Then, add paraffin oil in 2-5 batches and continue mixing to allow the paraffin oil to gradually penetrate the rubber matrix. Next, add zinc oxide and stearic acid and continue mixing for 2-5 minutes. Then add PEG4000 and a dispersant and continue mixing for 1-4 minutes. Add a modifier and continue mixing for 1-5 minutes. Finally, add light calcium carbonate and carbon... Continue mixing the black EPDM compound for 10-20 minutes at a temperature of 75-95℃ to obtain a black EPDM compound. Transfer the obtained black EPDM compound to a two-roll mill for thin-pass processing, with the roll gap controlled at 0.5-2mm. After thin-passing 3-8 times, sheet out and cool to room temperature to obtain adhesive component A. Mix sulfur, zinc dibutyldithiocarbamate, zinc dimethyldithiocarbamate, 2-mercaptobenzothiazole, and N-cyclohexyl-2-benzothiazole sulfenamide evenly to obtain adhesive component B. Step 2: Before use, dilute the adhesive B component in gasoline and stir to form a uniform diluted solution of B component; Step 3: Before the hot-melt welding operation, mix adhesive A with adhesive B diluted with gasoline and stir evenly to obtain a black adhesive paste material for hot-melt welding of EPDM rubber strips.

[0015] Preferably, in step 1, the plasticizing temperature is 65-75℃ and the plasticizing time is 4-6 min; the mixing temperature after adding light calcium carbonate and carbon black is 80-90℃ and the mixing time is 12-18 min. By controlling the above temperature and time range, it is possible to ensure that the EPDM rubber compound, paraffin oil, filler and modifier are fully dispersed, and to avoid local scorching of the rubber compound, abnormal increase in viscosity or decrease in uniformity of subsequent coating caused by excessively high mixing temperature or excessively long mixing time.

[0016] Preferably, in step 1, the open mill roll gap is 0.8-1.5 mm, and the number of thin passes is 4-6. Through the thin pass treatment, the carbon black, light calcium carbonate, and modifier in the black EPDM compound are further evenly distributed, reducing the impact of localized powder agglomeration on the continuity of the hot-melt joint interface.

[0017] This invention also provides the application of the black adhesive material in the hot-melt welding of EPDM rubber strips. In use, the ends of the hollow EPDM rubber strips to be joined are cut to a preset angle or preset end face shape, and dust, oil, and debris are removed from the cut ends. 0.3-0.8g of black adhesive material is taken for each hot-melt joint and evenly coated onto the cut end face, splicing corner, or hot-melt frame connection area of ​​the hollow EPDM rubber strip. A mold core is inserted into the hollow rubber strip coated with black adhesive material, and the two strips are aligned and connected through the mold core. The strip containing the mold core is placed into the hot-melt mold, ensuring the joint area is flat. Then, heating and pressing are performed at a temperature of 190-210℃ for 50-60 seconds. After hot-melt welding, the EPDM rubber strips are removed from the mold and allowed to cool naturally for 20-40 minutes. After cooling, excess adhesive and burrs at the joint are trimmed to obtain a black EPDM rubber strip hot-melt frame.

[0018] By combining the above coating amount and hot-melt welding conditions, the adhesive material can be fully spread on the cut end face and participate in the formation of the hot-melt interface transition layer, avoiding insufficient adhesive and interface discontinuity due to excessive coating, and also avoiding excessive adhesive overflow, local collapse or uneven joint appearance due to excessive coating.

[0019] The beneficial effects of this invention are: 1. Compared with the prior art, the present invention uses EPDM rubber, paraffin oil, zinc oxide, stearic acid, PEG4000, dispersant, light calcium carbonate, carbon black and vulcanization accelerator to form a black adhesive base system suitable for hot-melt bonding of EPDM rubber strips, so that the adhesive material has good material compatibility with the EPDM rubber strip body and can form a continuous black adhesive transition layer during the hot-melt bonding process.

[0020] 2. Compared with the prior art, the black adhesive material obtained by the present invention can maintain good tensile load-bearing capacity, peel strength, peel strength retention rate after hot air aging and compression rebound rate after wet heat in the joint area after hot fusion of EPDM rubber strips. It is suitable for use in EPDM rubber strip frames under long-term sealing and repeated compression conditions. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the preparation and application process of the black adhesive material for hot-melt bonding of EPDM rubber strips according to the present invention; Figure 2 This is a flow chart of the EPDM rubber strip hot-melt welding process of the present invention; Figure 3 This is a product image showing the application of black adhesive material to EPDM rubber strips according to the present invention. Detailed Implementation

[0022] The parameters and sources of the specific chemical substances used.

[0023] The EPDM 6950 uses Keltan rubber produced by Arlanxyn. ® 6950C; The EPDM 2470 uses Keltan rubber manufactured by Arlanxyn. ® 2470E; N550 carbon black was purchased from Cabot Corporation in the United States; N774 carbon black was purchased from Cabot Corporation in the United States; The dispersant was dispersant L-12, purchased from Patinou International Trading (Shanghai) Co., Ltd.

[0024] Example 1 A black adhesive material for hot-melt bonding of EPDM rubber strips includes adhesive component A and adhesive component B diluted with gasoline. Adhesive component A comprises 38.91 parts by weight of EPDM rubber, 15.56 parts by weight of paraffin oil, 2.33 parts by weight of zinc oxide, 0.58 parts by weight of stearic acid, 0.58 parts by weight of PEG4000, 0.39 parts by weight of dispersant, 11.67 parts by weight of light calcium carbonate, and 27.23 parts by weight of carbon black. Adhesive component B comprises 1 part by weight of sulfur, 0.4 parts by weight of zinc dibutyldithiocarbamate, 0.15 parts by weight of zinc dimethyldithiocarbamate, 0.4 parts by weight of 2-mercaptobenzothiazole, and 0.8 parts by weight of N-cyclohexyl-2-benzothiazole sulfenamide. The amount of gasoline added is 5 times the total mass of adhesive component B. The EPDM rubber is composed of 27.24 parts by weight of EPDM rubber 6950 and 11.67 parts by weight of EPDM rubber 2470; the carbon black is composed of 15.56 parts by weight of N550 carbon black and 11.67 parts by weight of N774 carbon black. The method for preparing the black adhesive material for hot-melt bonding of EPDM rubber strips includes the following steps: Step 1: EPDM rubber is added to an internal mixer for plasticizing at 70℃ for 5 minutes to form a uniform rubber matrix. Paraffin oil is then added in three batches and mixing continues. Zinc oxide and stearic acid are then added and mixing continues for 3 minutes. PEG4000 and a dispersant are added and mixing continues for 2 minutes. Light calcium carbonate and carbon black are then added and mixing continues for 15 minutes at 85℃ to obtain a uniformly colored black EPDM compound. The black EPDM masterbatch is then transferred to a two-roll mill for thin-pass processing, with a roll gap of 1 mm. After five passes, the material is sheeted and cooled to room temperature to obtain adhesive component A. Sulfur, zinc dibutyl dithiocarbamate, zinc dimethyl dithiocarbamate, 2-mercaptobenzothiazole, and N-cyclohexyl-2-benzothiazole sulfenamide are mixed evenly to obtain adhesive component B. Step 2: Before use, dilute the adhesive B component in gasoline and stir to form a uniform diluted solution of B component; Step 3: Before the hot-melt welding operation, mix adhesive A with adhesive B diluted with gasoline and stir evenly to obtain a black adhesive paste material for hot-melt welding of EPDM rubber strips.

[0025] Application of the black adhesive material for hot-melt bonding of EPDM rubber strips: In use, cut the ends of the hollow EPDM rubber strips to be bonded to a preset angle or preset end face shape, and remove dust, oil, and debris from the cut ends. Take 0.5g of black adhesive material for each hot-melt joint and evenly coat it onto the cut end face, splicing corner, or hot-melt frame connection area of ​​the hollow EPDM rubber strip. Insert the mold core into the hollow rubber strip coated with black adhesive material and align the two strips through the mold core. Place the strip containing the mold core into the hot-melt mold, ensuring the joint area is flush. Then, heat and press at a temperature of 200℃ for 55 seconds. After hot-melt bonding, remove the EPDM rubber strip from the mold and allow it to cool naturally for 30 minutes. After cooling, trim any excess adhesive and burrs at the joint to obtain the black EPDM rubber strip hot-melt frame.

[0026] The black adhesive material obtained in Example 1 should be uniformly black, without obvious layering, sedimentation, clumping, coarse particles, or local powder aggregation. The appearance inspection was conducted using a combination of visual observation and magnified observation. The EPDM rubber strip frame after heat fusion was placed under natural light or standard lighting conditions. First, the joint was visually inspected, then the joint surface and end-face transition area were observed using a 5x magnifying glass. The inspection included checking for bubbles, insufficient adhesive, cracks, misalignment, collapse, significant color difference, and abnormal adhesive overflow at the joint. Ten samples were tested. The results were as follows: no cracking, delamination, or delamination was found; no obvious bubbles or insufficient adhesive were found; there was no significant misalignment at the corner joints; the black adhesive material, when used for heat fusion of EPDM rubber strips, forms a continuous and uniform black adhesive transition layer at the joint, and the joint appearance has good consistency with the rubber strip body. During the tensile strength test of the joint, a strip-shaped specimen containing the joint was cut from the corner joint of the thermofused frame, with the thermofused joint located in the middle of the specimen. The two ends of the specimen were clamped on a universal testing machine and stretched at a speed of 100 mm / min. The maximum tensile force at which the specimen failed was recorded, and the failure location was observed. Five specimens were tested in each group. The test results are as follows: the average maximum tensile force was 188 N; the failure locations were all located in the colloidal area adjacent to the joint or in the local cohesive area of ​​the joint transition layer, and no neat separation along the coating interface was observed. During the joint peel strength test, two EPDM rubber strips were heat-fused together using the black adhesive material described in the example. A 10mm wide joint sample was then cut, and the peeling direction was along the joint interface. A universal testing machine was used to peel the strips at a speed of 50mm / min. The peeling force during the stable peeling stage was recorded and converted to peel strength per unit width. Five samples were tested in each group. The test results are as follows: the average peel strength was 4.9 N / mm. After peeling, no large-area interface separation was observed in the joint area. The main manifestations were local tearing of the rubber matrix or cohesive failure of the adhesive transition layer. This result indicates that the black adhesive material described in the example has good interfacial bonding ability with the EPDM rubber strip body. After heat fusion, the joint area is not prone to interface separation, which can meet the bonding strength requirements during corner splicing and heat fusion frame use. Compression resilience was used to evaluate whether hollow EPDM rubber strips could maintain their sealing elasticity after being heat-fused into a frame. Samples containing corner joints within the heat-fused frame were used as test samples. Each sample segment was 50 mm long, with the joint located in the middle of the segment. A compression testing device was used to compress the samples along the thickness direction to 50% of their original height. After holding this position for 24 hours, the samples were unloaded and allowed to recover at room temperature for 30 minutes. The recovered height was then measured. The compression resilience rate was calculated as follows: based on the sample height before compression, the sample height under compression, and the sample height after recovery, the degree of height recovery after unloading was calculated. Five samples were tested in each group. The results are as follows: the average compression resilience rate was 87.4%. Simultaneously, the joint area was observed; no joint cracking, adhesive layer detachment, or corner collapse expansion occurred after compression. This result indicates that the hollow EPDM rubber strips heat-fused using the black adhesive material described in the example still possess good elastic recovery ability after compression, and the joint area does not experience significant failure due to compression deformation. The aging resistance test includes hot air aging, ozone aging and damp heat aging. The test objects are all EPDM rubber strip sample segments containing heat-fused joints. During hot air aging testing, the samples were placed in an 80℃ hot air aging chamber for 168 hours. After aging, the samples were removed and left at room temperature for 2 hours before the joint appearance was observed, and the joint peel strength was retested. The test results showed that no cracking, delamination, or obvious hardening brittleness occurred at the joint after aging. The average peel strength of the aged samples was 4.32 N / mm, and compared with the average peel strength of 4.9 N / mm before aging, the peel strength retention rate was 88.2%. During ozone aging testing, the sample segment containing the joint was stretched by 20% and fixed, then placed in an ozone aging chamber for 72 hours at an ozone concentration of 50 pphm and a temperature of 40℃. After the test, the joint area was observed under a 2x magnifying glass. The test results showed that no visible cracks appeared on the joint surface and its adjacent colloid area, and there was no delamination or debonding of the joint transition layer. During the damp heat aging test, the sample was placed in a damp heat environment with a temperature of 70℃ and a relative humidity of 95% for 96 hours. After the treatment, it was placed at room temperature for 2 hours, and the joint condition was observed and the compression rebound test was repeated. The test results showed that there was no obvious stickiness, bulging, delamination and cracking at the joint after damp heat treatment. The average compression rebound rate of the sample was 83.96%. The above results indicate that the heat-fused joint formed by the black adhesive material described in the example can still maintain good bonding stability, crack resistance and compression recovery ability after being exposed to hot air, ozone and damp heat environment, and is suitable for EPDM rubber strip frames for long-term sealing and repeated compression.

[0027] Example 2 A black adhesive material for hot-melt bonding of EPDM rubber strips includes adhesive component A and adhesive component B diluted with gasoline. Adhesive component A comprises 38.91 parts by weight of EPDM rubber, 15.56 parts by weight of paraffin oil, 2.33 parts by weight of zinc oxide, 0.58 parts by weight of stearic acid, 0.58 parts by weight of PEG4000, 0.39 parts by weight of dispersant, 11.67 parts by weight of light calcium carbonate, 27.23 parts by weight of carbon black, and 1.2 parts by weight of modifier. Adhesive component B comprises 1 part by weight of sulfur, 0.4 parts by weight of zinc dibutyldithiocarbamate, 0.15 parts by weight of zinc dimethyldithiocarbamate, 0.4 parts by weight of 2-mercaptobenzothiazole, and 0.8 parts by weight of N-cyclohexyl-2-benzothiazole sulfenamide. The amount of gasoline added is 5 times the total mass of adhesive component B. The EPDM rubber is composed of 27.24 parts by weight of EPDM rubber 6950 and 11.67 parts by weight of EPDM rubber 2470; the carbon black is composed of 15.56 parts by weight of N550 carbon black and 11.67 parts by weight of N774 carbon black; the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and catechol in a mass ratio of 1:2. The method for preparing the black adhesive material for hot-melt bonding of EPDM rubber strips includes the following steps: Step 1: EPDM rubber is added to an internal mixer for plasticizing at 70℃ for 5 minutes to form a uniform rubber matrix. Paraffin oil is then added in three batches and mixing continues. Zinc oxide and stearic acid are then added and mixing continues for 3 minutes. PEG4000 and a dispersant are added and mixing continues for 2 minutes. A modifier is added and mixing continues for 3 minutes. Light calcium carbonate and carbon black are then added and mixing continues for 15 minutes at 85℃ to obtain a uniformly colored black EPDM compound. The black EPDM masterbatch is then transferred to a two-roll mill for thin-pass processing, with a roll gap of 1 mm. After five passes, the material is sheeted and cooled to room temperature to obtain adhesive component A. Sulfur, zinc dibutyl dithiocarbamate, zinc dimethyl dithiocarbamate, 2-mercaptobenzothiazole, and N-cyclohexyl-2-benzothiazole sulfenamide are mixed evenly to obtain adhesive component B. Step 2: Before use, dilute the adhesive B component in gasoline and stir to form a uniform diluted solution of B component; Step 3: Before the hot-melt welding operation, mix adhesive A with adhesive B diluted with gasoline and stir evenly to obtain a black adhesive paste material for hot-melt welding of EPDM rubber strips.

[0028] Application of the black adhesive material for hot-melt bonding of EPDM rubber strips: In use, cut the ends of the hollow EPDM rubber strips to be bonded to a preset angle or preset end face shape, and remove dust, oil, and debris from the cut ends. Take 0.5g of black adhesive material for each hot-melt joint and evenly coat it onto the cut end face, splicing corner, or hot-melt frame connection area of ​​the hollow EPDM rubber strip. Insert the mold core into the hollow rubber strip coated with black adhesive material and align the two strips through the mold core. Place the strip containing the mold core into the hot-melt mold, ensuring the joint area is flush. Then, heat and press at a temperature of 200℃ for 55 seconds. After hot-melt bonding, remove the EPDM rubber strip from the mold and allow it to cool naturally for 30 minutes. After cooling, trim any excess adhesive and burrs at the joint to obtain the black EPDM rubber strip hot-melt frame.

[0029] The appearance inspection was conducted using a combination of visual observation and 5x magnification. The results showed that no cracking, delamination, degumming, obvious bubbles, obvious glue shortage, or abnormal collapse was found at the joint of the EPDM rubber strip after hot-melting with the black adhesive material described in Example 2; the black transition layer on the joint surface was continuous, and the color of the end-face connection area was well consistent with the body of the rubber strip; no obvious coarse particle aggregation was observed under 5x magnification.

[0030] After peel strength testing of the joint, the fracture surface was observed. The damage mainly manifested as cohesive failure of the rubber matrix or mixed failure between the adhesive transition layer and the rubber body. No neat separation along the coating interface was observed. This result indicates that the co-addition of 2,4,6-trimercapto-1,3,5-triazine and catechol can enable the heat-fused joint to form a more continuous and stable interfacial transition layer, improving the interfacial bonding stability and peel resistance of the joint area.

[0031] Example 3 It is basically the same as Example 2, except that the modifier is composed of 2-mercapto-4,6-diamino-1,3,5-triazine and catechol in a mass ratio of 1:2.

[0032] The appearance inspection results showed that the surface of the EPDM rubber strip heat-melt joint made with the black adhesive material described in Example 3 was basically flat, and no obvious cracking, lack of adhesive, collapse, or delamination was found. The black transition layer at the joint could continuously cover the cut end face. However, under 5x magnification, slight unevenness in the interface transition was visible in some joint edge areas.

[0033] After peel strength testing of the joint, the fracture surface was observed, and the failure morphology showed a coexistence of interfacial peeling and a small amount of rubber cohesive failure, with some areas still showing detachment along the joint interface. This result indicates that although 2-mercapto-4,6-diamino-1,3,5-triazine has a triazine ring and a single thiol group, which can improve joint performance to a certain extent, its multi-point crosslinking assist ability is weaker than that of 2,4,6-trimercapto-1,3,5-triazine.

[0034] Example 4 It is basically the same as Example 2, except that the modifier is a mixture of 2,4-dimercapto-6-amino-1,3,5-triazine and catechol in a mass ratio of 1:2.

[0035] The appearance inspection results show that the overall appearance of the heat-fusion joint obtained in Example 4 is relatively flat, and no obvious bubbles, missing glue, cracks and collapses were found at the joint. The color consistency between the black glue transition layer and the EPDM rubber strip body is good.

[0036] After peel strength testing, the cross-section was observed, and the joint failure was mainly characterized by mixed failure, that is, some areas experienced cohesive failure of the colloid, while other areas experienced interfacial peeling. Compared with Example 3, the 2,4-dimercapto-6-amino-1,3,5-triazine in Example 4 has two thiol groups, which can further improve the crosslinking assistance effect of the joint thin layer, but its interfacial continuity and cohesive failure ratio are still lower than those of Example 2.

[0037] Example 5 It is basically the same as Example 2, except that the modifier is a mixture of melamine and catechol in a mass ratio of 1:2.

[0038] The appearance inspection results showed that the joint area obtained in Example 5 was able to form a basically continuous black adhesive layer, and no obvious delamination or through cracking was found. However, slight interface demarcation lines could be seen on some joint edges under 5x magnification.

[0039] After peel strength testing, the fracture surface was observed, and the damage morphology was mainly characterized by localized interfacial peeling, with a low proportion of cohesive damage. This result indicates that although melamine has a 1,3,5-triazine ring structure, it does not contain thiol groups, making it difficult for it to play a synergistic multi-point crosslinking auxiliary role with the vulcanization system in this system. Therefore, its improvement on the crosslinking stability of the joint thin layer is limited.

[0040] Example 6 It is basically the same as Example 2, except that the modifier is composed of cyanuric acid and catechin in a mass ratio of 1:2.

[0041] The appearance inspection results showed that the EPDM rubber strip hot-melt joint obtained in Example 6 did not show obvious cracking or delamination, but there was a slight granular feel in the transition layer of the joint. Under 5x magnification, a small number of granular uneven areas could be seen.

[0042] After peel strength testing, the fracture surface was observed, and the damage morphology was mainly characterized by localized interfacial peeling, with preferential detachment occurring near some particle aggregation areas. This result indicates that although cyanuric acid has a triazine ring structure and hydroxyl and ketone structures, it lacks a thiol group, resulting in insufficient auxiliary effect on vulcanization crosslinking. Furthermore, its strong polarity may affect its dispersion uniformity in the non-polar EPDM adhesive system.

[0043] Example 7 It is basically the same as Example 2, except that the modifier is a mixture of 2-mercaptopyrimidine and catechol in a mass ratio of 1:2.

[0044] Visual inspection results showed that the joint surface obtained in Example 7 was relatively smooth, with no obvious bubbles, missing adhesive, or collapse, and the black transition layer of the joint could cover the end face to be connected. However, under 5x magnification, slight discontinuities in the interface transition were visible at the edges of some joints.

[0045] After peel strength testing, the fracture surface was observed, and the damage morphology was still mainly characterized by localized interfacial peeling, with only a small number of colloidal cohesive damage areas. This result indicates that 2-mercaptopyrimidine, as a monothiol nitrogen-containing heterocyclic compound, can provide some interfacial interaction, but it does not possess the symmetrical three-point structure of the triazine ring and the synergistic effect of multiple thiol groups, thus its improvement on the overall stability of the joint is limited.

[0046] Example 8 It is basically the same as Example 2, except that the modifier is a mixture of 2-mercaptopyridine and catechol in a mass ratio of 1:2.

[0047] The appearance inspection results show that the overall appearance of the heat fusion joint obtained in Example 8 is basically qualified, and no obvious cracks, bubbles, missing glue and collapse were found. However, slight interface demarcation can be seen at the edge of some joints.

[0048] After joint peel strength testing, the fracture surface was observed, and the failure morphology was mainly characterized by localized interfacial peeling, with a low proportion of cohesive failure in the colloid. This result indicates that although 2-mercaptopyridine has a nitrogen-containing heterocycle and a thiol structure, it contains only one thiol group and lacks a 1,3,5-triazine ring structure, making it difficult to form the same multi-point crosslinking assistance and interfacial stabilizing effect as 2,4,6-trimercapto-1,3,5-triazine.

[0049] Example 9 It is basically the same as Example 2, except that the modifier is a mixture of 2,5-dimercapto-1,3,4-thiadiazole and catechol in a mass ratio of 1:2.

[0050] The appearance inspection results showed that the surface of the joint obtained in Example 9 was generally continuous, with no obvious glue shortage, bubbles, or delamination, and the black appearance of the joint area was relatively consistent. However, the edge areas of some samples felt slightly hard to the touch, and the local transition areas appeared slightly rigid under 5x magnification.

[0051] After peel strength testing, the fracture surface was observed. The failure morphology was mainly mixed failure, but some joint edge areas showed a harder fracture morphology. This result indicates that 2,5-dimercapto-1,3,4-thiadiazole has two thiol groups, which can improve the joint crosslinking and peel performance. However, it does not have the trimercaptotriazine structure of 2,4,6-trimercapto-1,3,5-triazine, and the joint flexibility and post-aging stability are still not as good as in Example 2.

[0052] Example 10 It is basically the same as Example 2, except that the modifier is a mixture of thiourea and catechol in a mass ratio of 1:2.

[0053] The appearance inspection results showed that the joint obtained in Example 10 did not have obvious cracking or delamination, but the uniformity of the joint transition layer was generally poor, and slight uneven dispersion could be seen in some areas under 5x magnification.

[0054] After peel strength testing, the fracture surface was observed, and the failure morphology was mainly characterized by localized interfacial peeling, with fewer cohesive failure areas. This result indicates that although thiourea contains sulfur and nitrogen elements, it does not possess triazine rings and polythiol structures, and therefore has limited effect on improving the uniformity of crosslinking and interfacial stability of the joint thin layer in EPDM non-polar adhesive systems.

[0055] Example 11 It is basically the same as Example 2, except that the modifier is 2,4,6-trimercapto-1,3,5-triazine.

[0056] The appearance inspection results show that the surface continuity of the joint obtained in Example 11 is improved compared with that in Example 1. No obvious bubbles, missing glue, cracks and collapses were found, and the joint edges are relatively flat.

[0057] After peel strength testing, the fracture surface was observed. The damage morphology showed that the cross-linking stability of the joint thin layer was improved, but localized interfacial peeling still existed. This result indicates that the addition of 2,4,6-trimercapto-1,3,5-triazine alone can improve the cross-linking uniformity of the joint thin layer, but due to the lack of interfacial anchoring effect of catechol on the cut end face and filler surface, its overall joint condition is still not as good as that of Example 2.

[0058] Example 12 It is basically the same as Example 2, except that the modifier is catechin.

[0059] The appearance inspection results show that the black adhesive layer at the joint obtained in Example 12 is relatively continuous, the color consistency between the joint and the EPDM strip body is good, and there are fewer coarse particles and missing adhesive on the joint surface under 5x magnification.

[0060] After peel strength testing, the fracture surface was observed, and the damage morphology showed improved interfacial bonding. However, the joint retention after aging was slightly lower than in Example 2, with a small number of interfacial detachment areas still visible. This result indicates that adding catechol alone can enhance the interfacial interaction between the adhesive and the cut end face and the filler surface, but it lacks the regulation of the crosslinking uniformity of the joint thin layer by 2,4,6-trimercapto-1,3,5-triazine. Therefore, the overall effect is lower than that of Example 2, where both are added synergistically.

[0061] Example 13 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and hydroquinone in a mass ratio of 1:2.

[0062] The appearance inspection results showed that the joint obtained in Example 13 had no obvious bubbles, missing glue, or cracks, but slight interface discontinuity was visible at the edges of some joints.

[0063] After peel strength testing, the fracture surface was observed, and the failure morphology was mainly characterized by localized interfacial peeling and a small amount of mixed failure. This result indicates that although hydroquinone contains two phenolic hydroxyl groups, these two hydroxyl groups are located at the para position, making it difficult to form a multi-point interfacial interaction between the ortho- and ortho-catechin hydroxyl groups. Therefore, its improvement on the anchoring ability of the joint interface is not as good as that of catechol.

[0064] Example 14 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and phenol in a mass ratio of 1:2.

[0065] The appearance inspection results showed that the hot-melt joint obtained in Example 14 could be basically formed without obvious cracking or delamination. However, the continuity of the joint transition layer was generally poor, and some samples showed slight interface demarcation under 5x magnification.

[0066] After peel strength testing, the fracture surface was observed, and the damage morphology was mainly characterized by localized interfacial peeling. This result indicates that phenol contains only one phenolic hydroxyl group and cannot form a relatively stable multi-point interfacial interaction with zinc oxide, light calcium carbonate, carbon black, and the cut end face through ortho-bisphenolic hydroxyl groups, unlike catechol. Therefore, the improvement in joint interface stability is limited.

[0067] Example 15 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and guaiacol in a mass ratio of 1:2.

[0068] The appearance inspection results show that the surface of the joint obtained in Example 15 is relatively flat, the continuity of the black transition layer of the joint is acceptable, and no obvious bubbles, missing glue, or collapse were found.

[0069] After peel strength testing, the fracture surface was observed, and the failure morphology was mainly mixed failure, but a small number of interfacial peeling areas still existed. This result indicates that guaiacol has one phenolic hydroxyl group and one ortho-methoxy group, which can provide a certain interfacial effect. However, the methoxy group cannot completely replace the ortho-phenolic hydroxyl group of catechol, so its interfacial anchoring effect is lower than that of catechol.

[0070] Example 16 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and 2-methylphenol in a mass ratio of 1:2.

[0071] The appearance inspection results showed that the joint obtained in Example 16 had no obvious bubbles, missing glue, or cracks, but a slight tendency for interface separation could be seen at the joint edge under 5x magnification.

[0072] After peel strength testing, the fracture surface was observed, and the damage morphology was mainly characterized by localized interfacial peeling, with a low proportion of cohesive damage in the colloid. This result indicates that although 2-methylphenol has an ortho-substituted structure, the ortho-methyl group cannot form effective hydrogen bonds or coordination with zinc oxide, light calcium carbonate, carbon black, or the cut end face, and cannot replace the interfacial anchoring effect of the ortho-bisphenol hydroxyl group of catechol.

[0073] Example 17 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and gallic acid in a mass ratio of 1:2.

[0074] The appearance inspection results showed that the joint obtained in Example 17 had good overall continuity, and no obvious cracking, delamination and collapse were found. However, under 5x magnification, some sample joints showed slight particle defects in the transition layer.

[0075] After peel strength testing, the fracture surface was observed to show mixed failure morphology, but there was a tendency for preferential detachment at local particle defects. This result indicates that gallic acid contains multiple phenolic hydroxyl and carboxyl groups, which can provide strong interfacial interaction. However, its high polarity results in lower dispersion stability in the EPDM non-polar adhesive system compared to catechol, which can easily cause local inhomogeneity and thus affect the stability of the joint.

[0076] Example 18 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and 1,2,3-pyrogallol in a mass ratio of 1:2.

[0077] The appearance inspection results showed that the surface continuity of the heat fusion joint obtained in Example 18 was good, and no obvious bubbles, missing glue or cracks were found at the joint. However, some samples showed slightly low local interface dispersion stability when observed under 5x magnification.

[0078] After peel strength testing, the fracture surface was observed, and the damage morphology was mainly mixed damage, but the proportion of cohesive damage was lower than in Example 2. This result indicates that 1,2,3-pyrogallol has three adjacent phenolic hydroxyl groups, resulting in strong interfacial interactions. However, its high polarity and reactivity may lead to local aggregation or decreased resin stability in the non-polar EPDM system. Therefore, its overall joint condition is not as good as that of Example 2, which uses catechol in combination with 2,4,6-trimercapto-1,3,5-triazine.

[0079] Example 19 It is basically the same as Example 2, except that the modifier is 2-mercapto-4,6-diamino-1,3,5-triazine.

[0080] Example 20 It is basically the same as Example 2, except that the modifier is 2,4-dimercapto-6-amino-1,3,5-triazine.

[0081] Example 21 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and catechol in a mass ratio of 2:1.

[0082] Example 22 It is basically the same as Example 2, except that the modifier is a mixture of 2,4,6-trimercapto-1,3,5-triazine and catechol in a mass ratio of 1:3.

[0083] Test Example 1 Table 1 Test results of comprehensive performance of EPDM rubber strip hot melt joints

[0084] As shown in Table 1, Example 1, without the addition of additional interfacial crosslinking adjustment components and interfacial anchoring components, had an average maximum tensile force of 188 N, an average peel strength of 4.9 N / mm, a peel strength retention rate of 88.2% after hot air aging, and a compression rebound rate of 83.96% after wet heat. The joint failure morphology still showed local interfacial peeling and a small amount of coarse particles, indicating that although the base adhesive could meet the basic hot-melt bonding requirements, it had limited improvement on the stability of the joint interface and the uniformity of crosslinking.

[0085] In Example 2, the simultaneous addition of 2,4,6-trimercapto-1,3,5-triazine and catechol increased the average maximum tensile force to 216 N, the average peel strength to 5.8 N / mm, the peel strength retention rate after hot air aging to 93%, and the compression rebound rate after humid heat to 86.8%. The joint failure morphology was mainly cohesive failure or mixed failure. These results indicate that 2,4,6-trimercapto-1,3,5-triazine can improve the continuity of the thin-layer vulcanization crosslinking of the joint, and catechol can enhance the interfacial anchoring effect of the adhesive on the cut end face, zinc oxide, light calcium carbonate, and carbon black surface. Together, they form a more stable composite transition layer in the joint area.

[0086] Examples 3-10, while retaining catechol, replaced 2,4,6-trimercapto-1,3,5-triazine with monomercaptotriazine, dimercaptotriazine, melamine, cyanuric acid, 2-mercaptopyrimidine, 2-mercaptopyridine, 2,5-dimercapto-1,3,4-thiadiazole, or thiourea. The average peel strength of the above examples was 5-5.4 N / mm, and the peel strength retention rate after hot air aging was 88.7-90.2%, both lower than that of Example 2. This result indicates that having only a triazine ring, monomercapto, dimercapto, or ordinary sulfur- and nitrogen-containing structures cannot achieve the multi-point crosslinking auxiliary effect produced by the trimercaptotriazine structure of 2,4,6-trimercapto-1,3,5-triazine.

[0087] Example 11 only added 2,4,6-trimercapto-1,3,5-triazine, and Example 12 only added catechol. The average peel strengths of the two were 5.4 N / mm and 5.6 N / mm, respectively. After hot air aging, the peel strength retention rates were 90.8% and 91.3%, respectively. Although both were better than Example 1, they were both lower than Example 2. This result shows that improving crosslinking uniformity or improving interfacial anchoring ability alone cannot achieve the comprehensive effect of using both in combination.

[0088] Examples 13-18, while retaining 2,4,6-trimercapto-1,3,5-triazine, replaced catechol with hydroquinone, phenol, guaiacol, 2-methylphenol, gallic acid, or 1,2,3-phenylpyrogallol. The average peel strength of the above examples was 5.1-5.6 N / mm, and the peel strength retention rate after hot air aging was 89.2-90.9%, which was also lower than that of Example 2. This result indicates that monophenolic hydroxyl, para-bisphenolic hydroxyl, ortho-methoxy, ortho-methyl, or polyhydroxy structures cannot completely replace the ortho-bisphenolic hydroxyl structure of catechol; catechol exhibits a better balance between interfacial interaction ability and EPDM paste dispersion stability.

[0089] Examples 19 and 20 used 2-mercapto-4,6-diamino-1,3,5-triazine and 2,4-dimercapto-6-amino-1,3,5-triazine alone, respectively. Their average peel strengths were 5 N / mm and 5.1 N / mm, respectively, and their peel strength retention rates after hot air aging were 88.8% and 89.4%, respectively, both lower than those of Examples 3 and 4. These results indicate that although the above-mentioned triazine compounds can improve the cross-linking state of the thin layer of the heat-fused joint to a certain extent when used alone, the lack of interfacial anchoring effect of catechol on the cut end face of the EPDM rubber strip and the surface of the inorganic filler makes it difficult to significantly improve the peel strength and retention performance after aging.

[0090] Examples 21 and 22 still used a blend of 2,4,6-trimercapto-1,3,5-triazine and catechol, but the mass ratios were adjusted to 2:1 and 1:3, respectively. Example 21 had an average maximum tensile force of 214 N, an average peel strength of 5.6 N / mm, a peel strength retention rate of 92% after hot air aging, and a compression rebound rate of 86% after wet heat. Example 22 had an average maximum tensile force of 212 N, an average peel strength of 5.5 N / mm, a peel strength retention rate of 91.7% after hot air aging, and a compression rebound rate of 85.8% after wet heat, both lower than Example 2. These results indicate that when the proportion of 2,4,6-trimercapto-1,3,5-triazine is high, the cross-linking effect of the joint thin layer is enhanced, but the interfacial anchoring effect is relatively insufficient; when the proportion of catechol is high, the interfacial effect is enhanced, but the cross-linking regulation effect is relatively insufficient, and an excess of polar components may affect its dispersion stability in the EPDM non-polar adhesive system.

[0091] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A black mastic material for hot welding of EPDM rubber strips, characterized in that: Includes adhesive component A and adhesive component B diluted with gasoline; The adhesive A component comprises the following raw materials: EPDM rubber, paraffin oil, zinc oxide, stearic acid, PEG4000, dispersant, light calcium carbonate, carbon black, and modifier; The adhesive B component comprises the following raw materials: sulfur, zinc dibutyl dithiocarbamate, zinc dimethyl dithiocarbamate, 2-mercaptobenzothiazole, and N-cyclohexyl-2-benzothiazole sulfenamide.

2. The black adhesive material for hot-melt bonding of EPDM rubber strips as described in claim 1, characterized in that: By weight, adhesive A comprises the following raw materials: 35-45 parts EPDM rubber, 12-20 parts paraffin oil, 1.5-3.5 parts zinc oxide, 0.3-1 part stearic acid, 0.3-1 part PEG4000, 0.2-0.8 parts dispersant, 8-16 parts light calcium carbonate, 22-33 parts carbon black, and 0.8-2.5 parts modifier; By weight, the adhesive B component comprises the following raw materials: Sulfur 0.7-1.3 parts, zinc dibutyl dithiocarbamate 0.2-0.7 parts, zinc dimethyl dithiocarbamate 0.08-0.30 parts, 2-mercaptobenzothiazole 0.2-0.7 parts, N-cyclohexyl-2-benzothiazole sulfenamide 0.5-1.2 parts; The amount of gasoline added is 3-7 times the total mass of the adhesive B material; The mass ratio of adhesive A to undiluted adhesive B is (25-50):

1.

3. The black adhesive material for hot-melt bonding of EPDM rubber strips as described in claim 2, characterized in that: By weight, adhesive A comprises the following raw materials: 37-42 parts of EPDM rubber, 14-18 parts of paraffin oil, 2.0-2.8 parts of zinc oxide, 0.45-0.75 parts of stearic acid, 0.45-0.75 parts of PEG4000, 0.30-0.5 parts of dispersant, 10-14 parts of light calcium carbonate, 25-30 parts of carbon black, and 1-1.8 parts of modifier; By weight, the adhesive B component comprises the following raw materials: 0.8-1.2 parts sulfur, 0.3-0.5 parts zinc dibutyldithiocarbamate, 0.1-0.2 parts zinc dimethyldithiocarbamate, 0.3-0.5 parts 2-mercaptobenzothiazole, and 0.6-1 parts N-cyclohexyl-2-benzothiazole sulfenamide.

4. The black adhesive material for hot-melt bonding of EPDM rubber strips as described in claim 1, characterized in that: The modifier is an interfacial crosslinking regulating component and / or an interfacial anchoring component.

5. The black adhesive material for hot-melt bonding of EPDM rubber strips as described in claim 4, characterized in that: The interface crosslinking regulating component is at least one selected from 2,4,6-trimercapto-1,3,5-triazine, 2-mercapto-4,6-diamino-1,3,5-triazine, 2,4-dimercapto-6-amino-1,3,5-triazine, melamine, cyanuric acid, 2-mercaptopyrimidine, 2-mercaptopyridine, 2,5-dimercapto-1,3,4-thiadiazole, and thiourea.

6. The black adhesive material for hot-melt bonding of EPDM rubber strips as described in claim 4, characterized in that: The interface anchoring component is at least one of catechol, hydroquinone, phenol, guaiacol, 2-methylphenol, gallic acid, and 1,2,3-pyrogallol.

7. A method for preparing a black adhesive material for hot-melt bonding of EPDM rubber strips as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Put EPDM rubber into a mixer for plasticizing at a temperature of 60-80℃ for 3-8 minutes to form a rubber matrix. Add paraffin oil to the rubber matrix in 2-5 portions and continue mixing. Then add zinc oxide and stearic acid and continue mixing for 2-5 minutes. Next, add PEG4000 and dispersant and continue mixing for 1-4 minutes. Then add modifier and continue mixing for 1-5 minutes. Finally, add light calcium carbonate and carbon black and continue mixing for 1 minute. Mixing time is 0-20 minutes at a mixing temperature of 75-95℃ to obtain black EPDM compound; the black EPDM compound is then transferred to a two-roll mill for thin-pass processing, with the roll gap controlled at 0.5-2mm, and thin-passed 3-8 times before being sheeted and cooled to room temperature to obtain adhesive A; sulfur, zinc dibutyldithiocarbamate, zinc dimethyldithiocarbamate, 2-mercaptobenzothiazole, and N-cyclohexyl-2-benzothiazole sulfenamide are mixed evenly to obtain adhesive B; Step 2: Before use, dilute the adhesive B component in gasoline and stir to form a diluted B component solution; Step 3: Before the hot-melt welding operation, mix and stir the adhesive A material and B material dilution solution to obtain a black adhesive paste material for hot-melt welding of EPDM rubber strips.

8. The method for preparing the black adhesive material for hot-melt bonding of EPDM rubber strips as described in claim 7, characterized in that: In step 1, the plasticizing temperature is 65-75℃ and the plasticizing time is 4-6 min; the mixing temperature after adding light calcium carbonate and carbon black is 80-90℃ and the mixing time is 12-18 min; the roller gap is controlled at 0.8-1.5 mm and the number of thin passes is 4-6.

9. The application of a black adhesive material as described in any one of claims 1-6 in the hot-melt bonding of EPDM rubber strips, characterized in that, The black adhesive material is applied to the cut end face, splicing corner, or hot-melt frame connection area of ​​the EPDM rubber strip, so that a black adhesive transition layer is formed after the EPDM rubber strip is hot-melted.

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