Hot melt adhesive plug-in cap well combined with PVC coating and preparation method thereof

Abstract

This application relates to the field of automotive sealing cap preparation technology, and in particular to a hot melt adhesive cap that bonds well with PVC coatings and its preparation method. A hot melt adhesive cap that bonds well with PVC coatings includes a cap body and a hot melt adhesive layer. The cap body is made from the following raw materials in parts by weight: 40-60 parts of butyl rubber composition, 25-40 parts of polyurethane elastomer composition, 1-4 parts of crosslinking agent, 60-120 parts of filler composition, and 240-420 parts of co-solvent; the polyurethane elastomer composition is thermoplastic polyurethane (TPU) with a glass transition temperature (Tg) below -25°C. The hot melt adhesive cap prepared in this application exhibits good bonding stability with PVC coatings and has a wide damping temperature range, meaning it has good damping and vibration reduction performance and sound absorption and noise reduction performance at low temperatures.

Description

Technical Field

[0001] This application relates to the field of automotive sealing plug preparation technology, and in particular to a hot melt adhesive plug that bonds well with PVC coatings and its preparation method. Background Technology

[0002] Unpainted car bodies are often riddled with exposed holes, most of which need to be covered with caps during the manufacturing process. Numerous holes are present throughout the car body, particularly in the passenger compartment and engine compartment. The reasons for these pre-existing holes are as follows: a. To allow sufficient drainage of the electrophoretic coating solution for subsequent painting processes (such as in the trunk area where a spare tire is stored). b. To provide entry points for specific components (such as wiring harnesses) during car assembly. c. To meet the transportation needs of the car body during manufacturing (such as conveyor belts). d. To accommodate unused parts for optional models. Before the car rolls off the assembly line, these openings for draining the electrophoretic coating solution must be sealed with caps; otherwise, problems such as leaks, noise, and vibration will occur.

[0003] Currently, butyl rubber plugs are commonly used in automobiles due to their good shock absorption and sound insulation properties and economical price. However, they have the following problems: the incompatibility between butyl rubber plugs and PVC coatings leads to low bonding strength. After the intermediate and topcoat baking processes (140-170℃), delamination and bubbles appear between the butyl rubber plug surface and the PVC coating, affecting the sealing quality of the plugs and consequently impacting the vehicle's waterproofing, sound absorption and heat insulation, and damping performance.

[0004] In response to the problem in the aforementioned related technologies that delamination and air bubbles appear between the butyl rubber plug surface and the PVC coating after the intermediate coating and topcoat baking (140-170℃) in the next stage, affecting the plug sealing quality, this application provides a hot melt adhesive plug that bonds well with PVC coating and its preparation method. Summary of the Invention

[0005] To address the technical challenge of low bonding strength between butyl rubber plugs and PVC coatings in the prior art, which affects the waterproofing, sound absorption, heat insulation, and damping performance of automobiles, this application provides a hot melt adhesive plug that bonds well with PVC coatings and its preparation method.

[0006] The hot melt adhesive plug that bonds well with PVC coatings provided in this application is achieved through the following method:

[0007] A hot melt adhesive cap that bonds well with PVC coatings includes a cap body and a hot melt adhesive layer. The cap body includes a cap and a cap retainer integrally formed on the lower surface of the cap. The cap is bent downwards to form a cap edge. An annular retainer is integrally formed on the outer periphery of the end of the cap retainer facing away from the cap body. A hot melt adhesive filling area is formed on the lower surface of the cap edge, the outer periphery of the cap retainer, and the annular retainer. The hot melt adhesive layer fills the hot melt adhesive filling area and is flush with the upper surface of the annular retainer.

[0008] The plug is made from the following raw materials in parts by weight: 40-60 parts of butyl rubber composition, 25-40 parts of polyurethane elastomer composition, 1-4 parts of crosslinking agent, 60-120 parts of filler composition, and 240-420 parts of cosolvent.

[0009] The co-solvent is toluene and / or acetone; the filler composition is composed of at least one of carbon black, silica, and worm graphite combined with at least one of montmorillonite, titanium dioxide, carbon fiber, boron nitride nanosheets, graphene, halloysite nanosheets, carbon nanotubes, silicon carbide whiskers, and aramid fiber.

[0010] The butyl rubber composition comprises 30-40 parts of butyl rubber, 5-10 parts of ethylene propylene diene monomer (EPDM) rubber, 2-8 parts of hydroxyl-terminated polybutadiene with a molecular weight of 2000-4500, 0.1-0.4 parts of initiator, 0.5-2 parts of vulcanizing agent, 0.5-2 parts of accelerator, 0.5-2 parts of dispersant, 1-2 parts of antioxidant, and 1-5 parts of softener.

[0011] The initiator is at least one of azobisisobutyronitrile, benzoyl peroxide, and potassium persulfate; the vulcanizing agent is composed of zinc oxide and / or monatomic zinc-doped carbon black combined with at least one of sulfur, colloidal sulfur, and sulfur monochloride; the accelerator is at least one of sulfenamide accelerators, thiuram accelerators, and dithiocarbamate accelerators; the dispersant is composed of a silane coupling agent combined with at least one of stearate and titanate coupling agents; and the antioxidant is composed of at least one of nano-silicon nitride and nano-silica combined with at least one of phenolic antioxidants and heterocyclic antioxidants.

[0012] The hot melt adhesive plug prepared in this application is installed on the sheet metal opening of the automobile frame and then baked with PVC undercoat paint (150-180℃), intermediate coat and topcoat (140-170℃). The hot melt adhesive plug has good bonding stability with the PVC paint and good thermal stability, ensuring good overall shock absorption and sound absorption performance. In addition, the hot melt adhesive plug has a wide damping temperature range, that is, it has good damping and shock absorption performance and sound absorption and noise reduction performance at low temperatures.

[0013] Preferably, the lower surface of the plug cap is integrally formed with a first grid-shaped adhesive texture, and the outer surface of the plug post without the annular sleeve is integrally formed with a second grid-shaped adhesive texture; the upper surface of the annular sleeve is integrally formed with a third grid-shaped adhesive texture; the upper surface of the plug cap combined with the PVC coating is molded and imprinted with a plurality of mutually spaced irregularly shaped adhesive grooves; the irregularly shaped adhesive grooves are one of the following: inverted umbrella shape, inverted cap shape, inverted mushroom shape, and inverted cone shape.

[0014] The surface of the molding plate used to form the irregular adhesive groove is micro-carved with irregular protrusions, and the irregular protrusions are at least one of umbrella shape, hat shape, mushroom shape and cone shape.

[0015] By adopting the above technical solution, the bonding stability between the hot melt adhesive plugging surface and the PVC coating can be effectively improved.

[0016] Preferably, the hot melt adhesive cap is made from the following raw materials in parts by weight: 48-50 parts of butyl rubber composition, 32-35 parts of polyurethane elastomer composition, 1.8-2.4 parts of crosslinking agent, 80-100 parts of filler composition, and 336-372 parts of cosolvent; the cosolvent is toluene and acetone in a mass ratio of 1:(0.1-1); the crosslinking agent comprises a polyether containing maleimide groups with a molecular weight of 500-5000, a carbon black additive with aluminum chloride loaded on the surface, and a multi-walled polyether with thiol-terminated ends and a molecular weight of 1000-5000; the mass ratio of the polyether containing maleimide groups, the multi-walled polyether with thiol-terminated ends, and the carbon black additive with aluminum chloride loaded on the surface is (0.8-1):1:(0.08-0.20).

[0017] Preferably, the polyether containing maleimide groups is α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 500-1000 and / or α-biotin-ω-maleimide polyethylene glycol with a molecular weight of 2000-5000; the sulfhydryl-terminated multi-walled polyether is a three-arm polyethylene glycol thiol with a molecular weight of 2000-5000 and / or a four-arm polyethylene glycol thiol.

[0018] The use of soft segment crosslinking agents in this application not only improves the crosslinking density of the butyl rubber network and enhances the overall mechanical properties and heat resistance, but also ensures a wide damping temperature range. Furthermore, an appropriate amount of soft segment crosslinking agent can crosslink with the linear polymer chains in the polyurethane elastomer, thereby facilitating energy transfer between the polyurethane elastomer polymer chains. Under the premise of ensuring a wide overall damping temperature range, it can improve the overall mechanical properties, creep resistance, dimensional stability, heat resistance, wear resistance, sound absorption, vibration damping, and damping properties.

[0019] Preferably, the butyl rubber composition comprises 30-32 parts butyl rubber, 6-8 parts ethylene propylene diene monomer (EPDM) rubber, 3-6 parts hydroxyl-terminated polybutadiene with a molecular weight of 2000-4500, 0.2-0.28 parts initiator, 0.8-1.6 parts vulcanizing agent, 1-1.5 parts accelerator, 1.6-2.0 parts dispersant, 1.6-2.0 parts antioxidant, and 4-5 parts softener; the initiator is azobisisobutyronitrile (AIB) and potassium persulfate in a mass ratio of 1:1; the vulcanizing agent is monoatom zinc-doped carbon black and sulfur in a mass ratio of (0.1:1). The composition is as follows: 1:1; the accelerator is composed of N-cyclohexyl-2-benzothiazole sulfenamide and zinc dibutyldithiocarbamate in a mass ratio of 1:(0.05-0.15); the dispersant is composed of silane coupling agent KH-570 and titanate coupling agent KR238S in a mass ratio of 1:(0.2-0.4); the antioxidant is composed of nano-silicon nitride, nano-silica, and 2,4-dimethyl-6-tert-butylphenol in a mass ratio of 1:1:(2-4); the softener is at least one of naphthenic oil, dibutyl ester, and paraffin oil.

[0020] Preferably, the butyl rubber composition comprises 32 parts of butyl rubber, 8 parts of ethylene propylene diene monomer (EPDM) rubber, 5 parts of hydroxyl-terminated polybutadiene with a molecular weight of 2500-3600, 0.25 parts of initiator, 1.5 parts of vulcanizing agent, 1.5 parts of accelerator, 1.8 parts of dispersant, 2.0 parts of antioxidant, and 5 parts of softener.

[0021] Preferably, the filler composition is made from the following raw materials in weight percentages: 5-10 wt% ≥800 mesh worm graphite, 0.5-3 wt% carbon nanofibers, 0.5-3 wt% boron nitride nanosheets, 0.5-3 wt% graphene, 0.2-1.0 wt% silicon carbide whiskers, and the balance being carbon black.

[0022] By adopting the above technical solution, while ensuring good bonding stability between the hot melt adhesive cap and the PVC coating, the hot melt adhesive cap can be endowed with good sound absorption and vibration damping performance, heat resistance stability and excellent flame retardant and fireproof safety.

[0023] Preferably, the thermoplastic polyurethane (TPU) has a Shore hardness of 30-65A; the hard segment content of the thermoplastic polyurethane (TPU) is 35-45 wt%; the thermoplastic polyurethane (TPU) is made from the following raw materials: diisocyanate, polyol, chain extender, catalyst, and antioxidant; the diisocyanate is composed of aliphatic diisocyanate and aromatic diisocyanate in a molar ratio of (6-7):(3-4); the chain extender is a small molecule diol; the molar ratio of -NCO in the diisocyanate to the total -OH molar ratio of the polyol and the chain extender is 0.99-1.01; the catalyst is organobismuth and / or organotin; the polyol is composed of at least one of polyether diol with a molecular weight of 1800-3200, polyester diol with a molecular weight of 1000-3000, polycarbonate diol with a molecular weight of 1000-3000, and hydroxyl-terminated polybutadiene with a molecular weight of 1000-4500.

[0024] By adopting the above technical solution, the glass transition region of the hot melt adhesive cap formed by IIR / TPU compounding is relatively wide, giving it a wider damping temperature range, that is, it has good damping and vibration reduction performance and sound absorption and noise reduction performance at low temperatures.

[0025] The present application provides a method for preparing a hot melt adhesive cap that bonds well with PVC coatings, which is achieved through the following steps:

[0026] Step 1: Mix the butyl rubber composition and 30-60 parts of filler composition in an internal mixing and open milling process, and let it stand for 24-48 hours to obtain a compound. The obtained compound is then subjected to extrusion, calendering, cooling, sample cutting, and vulcanization treatment to obtain pre-made butyl rubber.

[0027] Step 2: The obtained pre-prepared butyl rubber is swollen in 180-240 parts of a co-solvent and mixed well to obtain a butyl rubber swelling solution;

[0028] Simultaneously, the polyurethane elastomer composition is swollen in the remaining 60-180 parts of the co-solvent and mixed evenly to obtain a semi-finished TPU swelling solution. The remaining 30-60 parts of the filler composition are added to the obtained TPU swelling solution, and after stirring and mixing evenly, the accurately measured crosslinking agent is added to obtain the TPU swelling solution. The TPU swelling solution is then ultrasonically dispersed for 10-30 minutes to obtain the finished TPU swelling solution.

[0029] Step 3: Perform ultrasonic dispersion treatment on the butyl rubber swelling liquid. Under ultrasonic dispersion, add the finished TPU swelling liquid to the butyl rubber swelling liquid at an addition rate of 1-2 g / min. After the addition is completed, continue ultrasonic dispersion treatment for 5-10 min to obtain a mixture.

[0030] Step 4: Inject the obtained mixture into the molding mold, heat to 110-116℃, evacuate to a molding pressure of 0.06-0.068MPa to remove the co-solvent, then pressurize with nitrogen to 3.0-3.6MPa, heat to 140-160℃ for secondary vulcanization treatment for 8-12 minutes, then cool down to 80-85℃ at 2-4℃ / min and hold for 10-30 minutes, depressurize to normal pressure, and allow to cool naturally to room temperature to obtain the cap body. Fill the hot melt adhesive filling area of ​​the cap body to obtain the finished hot melt adhesive cap.

[0031] Preferably, in step one, the butyl rubber composition and 30-60 parts of filler composition are subjected to intensive mixing and open milling, and then left to stand for 24 hours to obtain a compound. The obtained compound is then extruded, calendered, cooled, and cut into samples to obtain preforms. The preforms are left to stand at room temperature for 12 hours and then vulcanized for 180-240 seconds at a vulcanization temperature of 138-146℃ and a vulcanization pressure of 120-140 kg / cm2 to obtain preformed butyl rubber sheets.

[0032] The preparation method provided in this application is relatively simple, has relatively strong feasibility, and is easy to realize industrialized mass production.

[0033] Preferably, in step four, the obtained mixture is injected into a molding mold, heated to 110-116℃, and vacuumed to a molding pressure of 0.06-0.068MPa to remove the co-solvent. The molding mold is then sealed using a molding plate, the surface of which is micro-carved with irregularly shaped protrusions, which are at least one of umbrella, cap, mushroom, and cone shapes. The molding mold is then transferred to a vacuum autoclave and pressurized with nitrogen to 3.0-3.6MPa, heated to 140-160℃ for a secondary vulcanization treatment for 8-12 minutes, then cooled to 80-85℃ at a rate of 2-4℃ / min and held for 10-30 minutes. The pressure is then released to atmospheric pressure and allowed to cool naturally to room temperature to obtain a cap. Hot melt adhesive is then filled into the hot melt adhesive filling area of ​​the cap to obtain the finished hot melt adhesive cap.

[0034] By adopting the above technical solution, an irregularly shaped tack-enhancing groove can be formed on the surface of the finished hot melt adhesive plug, which can improve its bonding stability with PVC coating, thereby ensuring the waterproof performance, sound absorption and heat insulation performance, and damping and shock absorption performance of the whole vehicle.

[0035] In summary, this application has the following advantages:

[0036] 1. The hot melt adhesive plug prepared in this application has good bonding stability with PVC coating, and the hot melt adhesive plug has a wide damping temperature range, that is, it has good damping and vibration reduction performance and sound absorption and noise reduction performance at low temperature.

[0037] 2. Forming irregularly shaped tack-enhancing grooves on the surface of the finished hot melt adhesive cap can improve its bonding stability with PVC coatings, effectively ensuring the waterproof performance, sound absorption and heat insulation performance, and damping and shock absorption performance of the entire vehicle.

[0038] 3. The preparation method provided in this application is relatively simple, has relatively strong feasibility, and is easy to realize industrialized mass production. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 in this application.

[0040] In the diagram, 1 is the plug cover; 11 is the plug cap; 12 is the plug retainer; 13 is the annular retainer; 2 is the hot melt adhesive layer; and 20 is the hot melt adhesive filling area. Detailed Implementation

[0041] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples and comparative examples. Example

[0042] refer to Figure 1 A hot melt adhesive cap that bonds well with PVC coatings includes a cap body 1 and a hot melt adhesive layer 2. The cap body 1 includes a cap 11 and a cap retainer 12 integrally formed on the lower surface of the cap 11. The cap 11 is bent downwards to form a cap edge. An annular retainer 13 is integrally formed on the outer periphery of the end of the cap retainer 12 facing away from the cap body 1. A hot melt adhesive filling area 20 is formed on the lower surface of the cap edge, the outer periphery of the cap retainer 12, and the annular retainer 13. The hot melt adhesive layer 2 fills the hot melt adhesive filling area 20, and its lower surface is flush with the upper surface of the annular retainer 13. To improve the bonding stability between the cap and the vehicle frame, the lower surface of the cap has a first grid-shaped adhesive texture integrally formed, the outer surface of the cap post 12 without the annular retainer 13 has a second grid-shaped adhesive texture integrally formed, and the upper surface of the annular retainer 13 has a third grid-shaped adhesive texture integrally formed. The upper surface of the cap 11 bonded to the PVC coating is molded with several mutually spaced irregular adhesive grooves, which can be selected from one of the following shapes: inverted umbrella, inverted cap, inverted mushroom, or inverted cone.

[0043] The plug is made from the following raw materials in parts by weight: 40-60 parts of butyl rubber composition, 25-40 parts of polyurethane elastomer composition, 1-4 parts of crosslinking agent, 60-120 parts of filler composition, and 240-420 parts of cosolvent.

[0044] Preferably, the hot melt adhesive cap is made from the following raw materials in parts by weight: 48-50 parts of butyl rubber composition, 32-35 parts of polyurethane elastomer composition, 1.8-2.4 parts of crosslinking agent, 80-100 parts of filler composition, and 336-372 parts of cosolvent.

[0045] The co-solvent is toluene and / or acetone, preferably, the co-solvent is toluene and acetone in a mass ratio of 1:(0.1-1).

[0046] The crosslinking agent comprises a polyether containing maleimide groups with a molecular weight of 500-5000, a carbon black additive with aluminum chloride loaded on the surface, and a sulfhydryl-terminated multi-walled polyether with a molecular weight of 1000-5000. The mass ratio of the polyether containing maleimide groups, the sulfhydryl-terminated multi-walled polyether, and the carbon black additive with aluminum chloride loaded on the surface is (0.8-1):1:(0.08-0.20). The polyether containing maleimide groups is α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 500-1000 and / or α-biotin-ω-maleimide polyethylene glycol with a molecular weight of 2000-5000; the sulfhydryl-terminated multi-walled polyether is a three-armed polyethylene glycol thiol and / or a four-armed polyethylene glycol thiol with a molecular weight of 2000-5000.

[0047] The filler composition comprises at least one of carbon black, silica, and worm graphite, combined with at least one of montmorillonite, titanium dioxide, carbon fiber, boron nitride nanosheets, graphene, halloysite nanosheets, carbon nanotubes, silicon carbide whiskers, and aramid fiber. Preferably, the filler composition is made from the following raw materials in the indicated weight percentages: 5-10 wt% ≥800 mesh worm graphite, 0.5-3 wt% carbon nanofibers, 0.5-3 wt% boron nitride nanosheets, 0.5-3 wt% graphene, 0.2-1.0 wt% silicon carbide whiskers, with the balance being carbon black.

[0048] The butyl rubber composition comprises 30-40 parts of butyl rubber, 5-10 parts of ethylene propylene diene monomer (EPDM) rubber, 2-8 parts of hydroxyl-terminated polybutadiene with a molecular weight of 2000-4500, 0.1-0.4 parts of initiator, 0.5-2 parts of vulcanizing agent, 0.5-2 parts of accelerator, 0.5-2 parts of dispersant, 1-2 parts of antioxidant, and 1-5 parts of softener.

[0049] Preferably, the butyl rubber composition comprises 30-32 parts of butyl rubber, 6-8 parts of ethylene propylene diene monomer (EPDM) rubber, 3-6 parts of hydroxyl-terminated polybutadiene with a molecular weight of 2000-4500, 0.2-0.28 parts of initiator, 0.8-1.6 parts of vulcanizing agent, 1-1.5 parts of accelerator, 1.6-2.0 parts of dispersant, 1.6-2.0 parts of antioxidant, and 4-5 parts of softener.

[0050] The softener is at least one of naphthenic oil, dibutyl ester, and paraffin oil.

[0051] The initiator is at least one of azobisisobutyronitrile, benzoyl peroxide, and potassium persulfate. Preferably, the initiator is composed of azobisisobutyronitrile and potassium persulfate in a mass ratio of 1:1.

[0052] The vulcanizing agent is composed of zinc oxide and / or monatomic zinc-doped carbon black combined with at least one of sulfur, colloidal sulfur, and sulfur monochloride. Preferably, the vulcanizing agent is composed of monatomic zinc-doped carbon black and sulfur in a mass ratio of (0.1-0.25):1.

[0053] The accelerator is at least one of sulfenamide accelerators, thiuram accelerators, and dithiocarbamate accelerators. Preferably, the accelerator is composed of N-cyclohexyl-2-benzothiazole sulfenamide and zinc dibutyldithiocarbamate in a mass ratio of 1:(0.05-0.15).

[0054] The dispersant is composed of a silane coupling agent combined with at least one of stearate and titanate coupling agents. Preferably, the dispersant is composed of silane coupling agent KH-570 and titanate coupling agent KR 238S in a mass ratio of 1:(0.2-0.4).

[0055] The antioxidant is composed of at least one of nano-silicon nitride and nano-silica, combined with at least one of phenolic antioxidants and heterocyclic antioxidants. Preferably, the antioxidant is composed of nano-silicon nitride, nano-silica, and 2,4-dimethyl-6-tert-butylphenol in a mass ratio of 1:1:(2-4).

[0056] The Shore hardness of thermoplastic polyurethane (TPU) is 30-65A. The hard segment content of thermoplastic polyurethane (TPU) is 35-45 wt%.

[0057] Thermoplastic polyurethane (TPU) is made from the following raw materials: diisocyanate, polyol, chain extender, catalyst, and antioxidant. The diisocyanate is composed of aliphatic diisocyanate and aromatic diisocyanate in a molar ratio of (6-7):(3-4), where the aliphatic diisocyanate is hexamethylene diisocyanate (HDI) and the aromatic diisocyanate is diphenylmethane diisocyanate (MDI). The chain extender is a small molecule diol, preferably 1,6-hexanediol. The molar ratio of -NCO in the diisocyanate to the total -OH molar ratio of the polyol and chain extender is 0.99-1.01. The catalyst is organobismuth and / or organotin. The polyol is composed of at least one of the following: polyether diol with a molecular weight of 1800-3200, polyester diol with a molecular weight of 1000-3000, polycarbonate diol with a molecular weight of 1000-3000, and hydroxyl-terminated polybutadiene with a molecular weight of 1000-4500.

[0058] A method for preparing a hot melt adhesive plug that bonds well with PVC coatings includes the following steps:

[0059] Step 1: The butyl rubber composition and 30-60 parts of filler composition are subjected to intensive mixing and open milling, and then left to stand for 24-48 hours to obtain a compound. The obtained compound is then extruded, calendered, cooled, and cut into samples to obtain preforms. The preforms are left to stand at room temperature for 12-24 hours and then vulcanized for 180-240 seconds at a vulcanization temperature of 138-146℃ and a vulcanization pressure of 120-140 kg / cm². 2 Pre-made butyl rubber sheets can be obtained;

[0060] Step 2: The obtained pre-prepared butyl rubber is swollen in 180-240 parts of a co-solvent and mixed well to obtain a butyl rubber swelling solution;

[0061] Simultaneously, the polyurethane elastomer composition is swollen in the remaining 60-180 parts of the co-solvent and mixed evenly to obtain a semi-finished TPU swelling solution. The remaining 30-60 parts of the filler composition are added to the obtained TPU swelling solution, and after stirring and mixing evenly, the accurately measured crosslinking agent is added to obtain the TPU swelling solution. The TPU swelling solution is then ultrasonically dispersed for 10-30 minutes to obtain the finished TPU swelling solution.

[0062] Step 3: Perform ultrasonic dispersion treatment on the butyl rubber swelling liquid. Under ultrasonic dispersion, add the finished TPU swelling liquid to the butyl rubber swelling liquid at an addition rate of 1-2 g / min. After the addition is completed, continue ultrasonic dispersion treatment for 5-10 min to obtain a mixture.

[0063] Step 4: Inject the obtained mixture into the molding mold, heat to 110-116℃, evacuate to a molding pressure of 0.06-0.068MPa to remove the co-solvent, then pressurize with nitrogen to 3.0-3.6MPa, heat to 140-160℃ for secondary vulcanization treatment for 8-12 minutes, then cool down to 80-85℃ at 2-4℃ / min and hold for 10-30 minutes, depressurize to atmospheric pressure, and allow to cool naturally to room temperature to obtain the cap body 1. Fill the hot melt adhesive filling area 20 of the cap body 1 with hot melt adhesive to obtain the finished hot melt adhesive cap.

[0064] Example 1: A hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 320 parts of cosolvent - toluene.

[0065] The crosslinking agent is composed of α-dibenzocyclooctyn-ω-maleimide polyethylene glycol (CAS: 1480516-75-3, Xiamen Sainobonger Biotechnology Co., Ltd.) with a molecular weight of 676.76, three-arm polyethylene glycol thiols (Xiamen Sainobonger Biotechnology Co., Ltd.) with a molecular weight of 2000, and carbon black additive with surface-loaded aluminum chloride in a mass ratio of 1:1.05:0.1. The preparation method of the carbon black additive with surface-loaded aluminum chloride is as follows: 10g of carbon black and 1g of aluminum chloride are placed in a planetary ball mill and subjected to dry high-speed ball milling under nitrogen protection at a speed of 2400 rpm for 30 minutes. After cooling, the product is obtained.

[0066] The filler composition consists of carbon black (rubber carbon black, CAS: 1333-86-4), worm graphite (Henan Liugong Graphite Co., Ltd., model LG98-01), carbon fiber (VGCF-H Japan Showa Denko, average fiber diameter 150nm, average fiber length 6μm, carbon content >99.95wt%), and graphene (rubber-grade multilayer graphene, brand Forchem, item number FQ-62) in a mass ratio of 90:7:2:1.

[0067] The butyl rubber composition consists of 32 parts butyl rubber (Beijing Yanshan Petrochemical Branch of Sinopec, butyl rubber 1751, unsaturation 1.74 mol%, number average molecular weight 236,000), 5 parts ethylene propylene diene monomer (Lanxess EPDM 2450), and 3 parts hydroxyl-terminated polybutadiene (Type IV, number average molecular weight 3*10). 3 CAS: 69102-90-5 (brand: Tianyuan Aviation Materials), 0.12 parts azobisisobutyronitrile (CAS No. 78-67-1), 0.12 parts potassium persulfate (CAS: 7727-21-1), 0.2 parts single-atom zinc-doped carbon black (customized by Guangxi Lianke Huaxin Materials, zinc doping rate 5wt%), 1 part sulfur (CAS No. 7704-34-9), 1 part N-cyclohexyl-2-benzothiazole sulfenamide (CAS: 95-33-0), 0.1 parts zinc dibutyldithiocarbamate (CAS#: 136-23-2), 1.6 parts silane coupling agent KH-570 (CAS NO: 2530-85-0), 0.4 parts titanate coupling agent KR 238S (CAS: 65467-75-6), 0.5 parts of nano silicon nitride (flake-shaped high-purity nano silicon nitride powder with an average particle size of 50-200nm, brand Wenlun Metal), 0.5 parts of nano silicon dioxide (CAS:7631-86-9, average particle size of 20nm, brand Tianxing New Materials, hydrophobic), 1 part of 2,4-dimethyl-6-tert-butylphenol (CAS#:1879-09-0), and 4 parts of plasticizer - dibutyl ester (CAS:84-74-2, brand Kanos).

[0068] The polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 94.54g of 3-methyl-1,5-pentanediol, 330g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000 (Jinan Yuyi Chemical Co., Ltd.), 100g of polybutylene adipate glycol (Shanghai Hongzhuang Chemical Technology Co., Ltd.) with a molecular weight of 2000, 60g of 1,6-hexanediol polycarbonate (Wuhan Kemike Biomedical Technology Co., Ltd.), and 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000 (Type IV, number average molecular weight 3*10). 3 CAS:69102-90-5, brand: Tianyuan Aviation Materials), 4g of antioxidant BHT, 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent S-3313.

[0069] The preparation method of the polyurethane elastomer composition is as follows: First, polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, polybutylene adipate glycol (PEA) with a molecular weight of 2000, and 1,6-hexanediol polycarbonate (PPD) with a molecular weight of 2000 are vacuum dehydrated at 110°C for 2 hours; then, 94.54 g of 3-methyl-1,5-pentanediol is fed into the first feed trough of a twin-screw extruder, and 330 g of accurately metered polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000 is added. PTMEG glycol, 100g of 2000 molecular weight polybutylene adipate diol, 60g of 2000 molecular weight 1,6-hexanediol polyphenyl carbonate, and 30g of 3000 molecular weight hydroxyl-terminated polybutadiene HTPB are fed into the second feed trough of a twin-screw extruder. Simultaneously, 114.37g of accurately measured hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), and 0.8g of caprylic / capric acid are added. Bismuth, 3g of leveling agent S-3313, 4g of antioxidant BHT, and 5g of zinc stearate are mixed evenly and then added to the third feed trough of a twin-screw extruder. The twin-screw extruder has a 16-stage barrel. The temperatures of the first to sixteenth barrel stages are set as follows: 170℃, 175℃, 180℃, 185℃, 190℃, 190℃, 180℃, 170℃, 165℃, 160℃, 160℃, 160℃, 155℃, 155℃. The liquid material after melting reaction at 155℃ and 150℃ is discharged from the extruder by a gear pump, granulated by water cooling, and dried in a fluidized bed dryer at 85℃ until the water content is <0.025% to obtain granules. The obtained granules are transferred to an oven and heat-conditioned at 80℃ for 24 hours to eliminate internal stress, thus obtaining TPU granules with a Shore hardness of 40A. The glass transition temperature of the obtained TPU granules is -62℃, the tensile strength is 7.85MPa, and the elongation at break is 1135%.

[0070] A method for preparing a hot melt adhesive plug that bonds well with PVC coatings includes the following steps:

[0071] Step 1: Carbon black, worm graphite, carbon fiber, and graphene are mixed in a mass ratio of 90:7:2:1 to form a filler. 100g of the resulting filler is then dry-mixed with 4g of KH-570 and 1g of titanate coupling agent KR 238S for 30min to obtain the finished filler composition.

[0072] Forty parts of a precisely measured butyl rubber composition (composed of butyl rubber, EPDM rubber, hydroxyl-terminated polybutadiene with a molecular weight of 3000, azobisisobutyronitrile, potassium persulfate, zinc-doped carbon black, sulfur, N-cyclohexyl-2-benzothiazole sulfenamide, zinc dibutyl dithiocarbamate, silane coupling agent KH-570, titanate coupling agent KR 238S, nano-silicon nitride, nano-silica, 2,4-dimethyl-6-tert-butylphenol, and softener dibutyl ester) and 50 parts of a finished filler composition were subjected to intensive mixing and open milling, and allowed to stand for 24 hours to obtain a compound. The obtained compound was then extruded, calendered, cooled, and cut into samples to obtain preforms. The preforms were allowed to stand at room temperature for 12 hours and then vulcanized for 200 seconds at a vulcanization temperature of 145℃ and a vulcanization pressure of 140 kg / cm². 2 Pre-made butyl rubber sheets can be obtained;

[0073] Step 2: The obtained pre-prepared butyl rubber is swollen in 220 parts of the co-solvent - toluene and mixed well to obtain a butyl rubber swelling solution;

[0074] Simultaneously, 40 parts of the polyurethane elastomer composition were swollen in the remaining 100 parts of the co-solvent and mixed evenly to obtain a semi-finished TPU swelling solution. The remaining 30 parts of the finished filler composition were added to the obtained TPU swelling solution and stirred evenly. Then, 2.5 parts of the accurately measured crosslinking agent were added to obtain the TPU swelling solution. The solution was ultrasonically dispersed (power 600W / frequency 40kHz) for 20 minutes to obtain the finished TPU swelling solution.

[0075] Step 3: Perform ultrasonic dispersion (600W power / 40kHz frequency) on the butyl rubber swelling liquid for 5 minutes. Under ultrasonic dispersion, add the finished TPU swelling liquid to the butyl rubber swelling liquid at an addition rate of 2g / min. After the addition is completed, continue ultrasonic dispersion for 8 minutes to obtain a mixture.

[0076] Step 4: Inject the obtained mixture into the molding mold, heat to 115℃, evacuate to a molding pressure of 0.06-0.062MPa to remove the co-solvent, then introduce nitrogen gas to pressurize to 3.MPa, raise the temperature to 148℃ for secondary vulcanization treatment for 12min, then cool down to 85℃ at 2℃ / min and hold for 30min, depressurize to normal pressure, and allow to cool naturally to room temperature to obtain the plug cap body. Fill the hot melt adhesive (automotive hot melt adhesive 8160M, hardness 55±5D, softening point 160℃±5℃, curing speed 2~6s, glass transition temperature -30℃, tensile strength ≥11.3MPa, Guangdong Shuntian New Materials Co., Ltd.) into the hot melt adhesive filling area of ​​the plug cap body to obtain the finished hot melt adhesive plug.

[0077] The difference between Example 2 and Example 1 is that the capping body of the hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 25 parts of polyurethane elastomer composition, 2 parts of crosslinking agent, 65 parts of filler composition, and 260 parts of cosolvent - toluene.

[0078] The difference between Example 3 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 60 parts of butyl rubber composition, 25 parts of polyurethane elastomer composition, 2.66 parts of crosslinking agent, 85 parts of filler composition, and 340 parts of cosolvent - toluene.

[0079] The difference between Example 4 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 84 parts of filler composition, and 336 parts of cosolvent - toluene.

[0080] The difference between Example 5 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 240 parts of cosolvent - toluene.

[0081] The difference between Example 6 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 280 parts of cosolvent - toluene.

[0082] The difference between Example 7 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 400 parts of cosolvent - toluene.

[0083] The difference between Example 8 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, 280 parts of cosolvent - toluene, and 40 parts of acetone.

[0084] The difference between Example 9 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 60 parts of filler composition, and 288 parts of cosolvent - toluene.

[0085] The difference between Example 10 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 90 parts of filler composition, and 348 parts of cosolvent - toluene.

[0086] The difference between Example 11 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 100 parts of filler composition, and 368 parts of cosolvent - toluene.

[0087] The difference between Example 12 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 120 parts of filler composition, and 408 parts of cosolvent - toluene.

[0088] The difference between Example 13 and Example 4 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 1 part of crosslinking agent, 84 parts of filler composition, and 336 parts of cosolvent - toluene.

[0089] The difference between Example 14 and Example 4 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 4 parts of crosslinking agent, 84 parts of filler composition, and 336 parts of cosolvent - toluene.

[0090] The difference between Example 15 and Example 4 is that the crosslinking agent is composed of α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 676.76, α-biotin-ω-maleimide polyethylene glycol with a molecular weight of 2000 (Xiamen Sainobang Biotechnology Co., Ltd.), three-arm polyethylene glycol thiol with a molecular weight of 2000, and carbon black additive with aluminum chloride loaded on the surface in a mass ratio of 1:1:2.1:0.1.

[0091] The difference between Example 16 and Example 4 is that the crosslinking agent is composed of α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 676.76, α-biotin-ω-maleimide polyethylene glycol with a molecular weight of 2000, tetra-arm polyethylene glycol thiol with a molecular weight of 2000 (Xiamen Sainobong Biotechnology Co., Ltd.), and carbon black additive with aluminum chloride loaded on the surface in a mass ratio of 1:1:2.1:0.1.

[0092] The difference between Example 17 and Example 4 is that the crosslinking agent is composed of α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 676.76, α-biotin-ω-maleimide polyethylene glycol with a molecular weight of 2000, three-arm polyethylene glycol thiols with a molecular weight of 2000, four-arm polyethylene glycol thiols with a molecular weight of 2000, and carbon black additives with aluminum chloride loaded on the surface in a mass ratio of 2:2:2.1:2.1:0.2.

[0093] The difference between Example 18 and Example 4 is that the crosslinking agent is composed of α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 676.76, α-biotin-ω-maleimide polyethylene glycol with a molecular weight of 3500, three-arm polyethylene glycol thiols with a molecular weight of 2000, four-arm polyethylene glycol thiols with a molecular weight of 5000, and carbon black additives with aluminum chloride loaded on the surface, in a mass ratio of 2:2:2.1:2.1:0.2.

[0094] The difference between Example 19 and Example 4 is that the filler composition consists of carbon black, silica (Cabot silica CAB-O-SIL, CAS: 68611-44-9), graphene, and boron nitride nanosheets (average thickness: <100nm, sheet diameter: 1-3µm, specific surface area: 30m²). 2 / g, Particle morphology: flakes; CAS:10043-11-5, Brand: Kemic), silicon carbide whiskers (D500B, diameter D:0.1-1um, length L:5-30um; Brand: Chaotai) are composed of 90:7:0.5:0.5:2 by mass ratio.

[0095] The difference between Example 20 and Example 4 is that the filler composition is composed of carbon black, worm graphite, boron nitride nanosheets, and silicon carbide whiskers in a mass ratio of 90:7:1:2.

[0096] The difference between Example 21 and Example 4 is that the filler composition is composed of carbon black, worm graphite, carbon fiber, graphene, boron nitride nanosheets, and silicon carbide whiskers in a mass ratio of 80:10:3:3:3:1.

[0097] The difference between Example 22 and Example 4 is that the filler composition is composed of carbon black, worm graphite, carbon fiber, graphene, boron nitride nanosheets, and silicon carbide whiskers in a mass ratio of 93.3:5:0.5:0.5:0.5:0.2.

[0098] The difference between Example 23 and Example 4 is that the filler composition is composed of carbon black, worm graphite, white carbon black, carbon fiber, graphene, boron nitride nanosheets, and silicon carbide whiskers in a mass ratio of 80:10:4:3:1:1:1.

[0099] The difference between Example 24 and Example 4 is that the filler composition is composed of carbon black, worm graphite, carbon fiber, graphene, boron nitride nanosheets, and silicon carbide whiskers in a mass ratio of 90:5:3:0.5:0.5:1.

[0100] The difference between Example 25 and Example 4 is that the filler composition is composed of carbon black, worm graphite, carbon fiber, graphene, boron nitride nanosheets, and silicon carbide whiskers in a mass ratio of 86:8:3:1.5:1:0.5.

[0101] The difference between Example 26 and Example 4 is that the butyl rubber composition consists of 30 parts butyl rubber, 5 parts EPDM rubber, 2 parts hydroxyl-terminated polybutadiene with a molecular weight of 3000, 0.111 parts azobisisobutyronitrile, 0.111 parts potassium persulfate, 0.185 parts single-atom zinc-doped carbon black, 0.925 parts sulfur, 0.925 parts N-cyclohexyl-2-benzothiazole sulfenamide, 0.093 parts zinc dibutyldithiocarbamate, 1.48 parts silane coupling agent KH-570, 0.37 parts titanate coupling agent KR 238S, 0.463 parts nano silicon nitride, 0.463 parts nano silica, 0.925 parts 2,4-dimethyl-6-tert-butylphenol, and 3.7 parts softener - dibutyl ester.

[0102] The difference between Example 27 and Example 4 is that the butyl rubber composition consists of 35 parts butyl rubber, 8 parts EPDM rubber, 4 parts hydroxyl-terminated polybutadiene with a molecular weight of 3000, 0.141 parts azobisisobutyronitrile, 0.141 parts potassium persulfate, 0.235 parts single-atom zinc-doped carbon black, 1.175 parts sulfur, 1.175 parts N-cyclohexyl-2-benzothiazole sulfenamide, 0.1175 parts zinc dibutyldithiocarbamate, 1.88 parts silane coupling agent KH-570, 0.47 parts titanate coupling agent KR 238S, 0.5875 parts nano silicon nitride, 0.5875 parts nano silica, 1.175 parts 2,4-dimethyl-6-tert-butylphenol, and 4.7 parts softener - dibutyl ester.

[0103] The difference between Example 28 and Example 4 is that the butyl rubber composition consists of 32 parts butyl rubber, 6 parts EPDM rubber, 3 parts hydroxyl-terminated polybutadiene with a molecular weight of 3000, 0.123 parts azobisisobutyronitrile, 0.123 parts potassium persulfate, 0.205 parts single-atom zinc-doped carbon black, 1.025 parts sulfur, 1.025 parts N-cyclohexyl-2-benzothiazole sulfenamide, 0.1025 parts zinc dibutyldithiocarbamate, 1.64 parts silane coupling agent KH-570, 0.41 parts titanate coupling agent KR 238S, 0.5125 parts nano silicon nitride, 0.5125 parts nano silica, 1.025 parts 2,4-dimethyl-6-tert-butylphenol, and 4.1 parts softener - dibutyl ester.

[0104] The difference between Example 29 and Example 4 is that the butyl rubber composition consists of 32 parts butyl rubber, 8 parts EPDM rubber, 5 parts hydroxyl-terminated polybutadiene with a molecular weight of 3000, 0.135 parts azobisisobutyronitrile, 0.135 parts potassium persulfate, 0.225 parts single-atom zinc-doped carbon black, 1.125 parts sulfur, 1.125 parts N-cyclohexyl-2-benzothiazole sulfenamide, 0.1125 parts zinc dibutyldithiocarbamate, 1.8 parts silane coupling agent KH-570, 0.45 parts titanate coupling agent KR 238S, 0.5625 parts nano silicon nitride, 0.5625 parts nano silica, 1.125 parts 2,4-dimethyl-6-tert-butylphenol, and 4.5 parts softener - dibutyl ester.

[0105] The difference between Example 30 and Example 4 is that the butyl rubber composition consists of 40 parts butyl rubber, 10 parts EPDM rubber, 8 parts hydroxyl-terminated polybutadiene with a molecular weight of 3000, 0.174 parts azobisisobutyronitrile, 0.174 parts potassium persulfate, 0.29 parts single-atom zinc-doped carbon black, 1.45 parts sulfur, 1.45 parts N-cyclohexyl-2-benzothiazole sulfenamide, 0.145 parts zinc dibutyldithiocarbamate, 2.32 parts silane coupling agent KH-570, 0.58 parts titanate coupling agent KR 238S, 0.725 parts nano silicon nitride, 0.725 parts nano silica, 1.45 parts 2,4-dimethyl-6-tert-butylphenol, and 5.8 parts softener - dibutyl ester.

[0106] The difference between Example 31 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 89.81g of 3-methyl-1,5-pentanediol, 300g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 2000 (Jinan Yuyi Chemical Co., Ltd.), 100g of polybutylene adipate diol with a molecular weight of 2000 (Shanghai Hongzhuang Chemical Technology Co., Ltd.), 30g of 1,6-hexanediol polycarbonate with a molecular weight of 1000 (Wuhan Kemike Biomedical Technology Co., Ltd.), 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000, 4g of antioxidant (BHT), 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent (S-3313). The obtained TPU granules have a Shore hardness of 46A, a glass transition temperature of -55℃, a tensile strength of 8.19MPa, and an elongation at break of 1092%.

[0107] The difference between Example 32 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 94.54g of 3-methyl-1,5-pentanediol, 240g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 2000 (Jinan Yuyi Chemical Co., Ltd.), 90g of polybutylene adipate diol with a molecular weight of 2000 (Shanghai Hongzhuang Chemical Technology Co., Ltd.), 25g of 1,6-hexanediol polycarbonate with a molecular weight of 1000 (Wuhan Kemike Biomedical Technology Co., Ltd.), 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000, 4g of antioxidant (BHT), 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent (S-3313). The obtained TPU granules have a Shore hardness of 55A, a glass transition temperature of -52℃, a tensile strength of 8.72MPa, and an elongation at break of 1025%.

[0108] The difference between Example 33 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 100.45g of 3-methyl-1,5-pentanediol, 240g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, 80g of polybutylene adipate glycol with a molecular weight of 2000, 40g of 1,6-hexanediol polycarbonate with a molecular weight of 2000, 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000, 4g of antioxidant BHT, 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent S-3313. The resulting TPU granules have a Shore hardness of 50A, a glass transition temperature of -57°C, a tensile strength of 8.07 MPa, and an elongation at break of 1132%.

[0109] The difference between Example 34 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 112.69g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 100.45g of 3-methyl-1,5-pentanediol, 240g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, 80g of polybutylene adipate glycol with a molecular weight of 2000, 40g of 1,6-hexanediol polycarbonate with a molecular weight of 2000, 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000, 4g of antioxidant BHT, 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent S-3313. The resulting TPU granules have a Shore hardness of 48A, a glass transition temperature of -58°C, a tensile strength of 7.61 MPa, and an elongation at break of 1195%.

[0110] The difference between Example 35 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 116.05g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 100.45g of 3-methyl-1,5-pentanediol, 240g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, 80g of polybutylene adipate glycol with a molecular weight of 2000, 40g of 1,6-hexanediol polycarbonate with a molecular weight of 2000, 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000, 4g of antioxidant BHT, 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent S-3313. The resulting TPU granules have a Shore hardness of 55A, a glass transition temperature of -55°C, a tensile strength of 8.71 MPa, and an elongation at break of 981%.

[0111] The difference between Example 36 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 94.54g of 3-methyl-1,5-pentanediol, 330g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, 100g of polybutylene adipate glycol with a molecular weight of 2000, 80g of 1,6-hexanediol polycarbonate with a molecular weight of 2000, 4g of antioxidant BHT, 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent S-3313. The resulting TPU granules have a Shore hardness of 42A, a glass transition temperature of -57°C, a tensile strength of 8.11 MPa, and an elongation at break of 1108%.

[0112] The difference between Example 37 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 94.54g of 3-methyl-1,5-pentanediol, 330g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000 (Jinan Yuyi Chemical Co., Ltd.), 100g of polybutylene adipate diol with a molecular weight of 2000 (Shanghai Hongzhuang Chemical Technology Co., Ltd.), 60g of 1,6-hexanediol polycarbonate with a molecular weight of 2000 (Wuhan Kemike Biomedical Technology Co., Ltd.), 35.5g of dihydroxyl-terminated long-chain alkyl silicone oil (IOTA-8865H) with a molecular weight of 3550 (Anhui Aiyota Silicone Oil Co., Ltd.), 4g of antioxidant (BHT), 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent (S-3313). The resulting TPU granules have a Shore hardness of 39A, a glass transition temperature of -64℃, a tensile strength of 8.09MPa, and an elongation at break of 1161%.

[0113] The difference between Example 38 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 94.54g of 3-methyl-1,5-pentanediol, 300g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, 100g of polybutylene adipate glycol with a molecular weight of 2000, 60g of 1,6-hexanediol polycarbonate with a molecular weight of 2000, 35.5g of dihydroxyl-terminated long-chain alkyl silicone oil IOTA-8865H (Anhui Aiyota Silicone Oil Co., Ltd.) with a molecular weight of 3550, 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000, 4g of antioxidant BHT, 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent S-3313. The resulting TPU granules have a Shore hardness of 42A, a glass transition temperature of -61℃, a tensile strength of 8.14MPa, and an elongation at break of 1157%.

[0114] The difference between Example 39 and Example 4 is that the polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 94.54g of 3-methyl-1,5-pentanediol, 300g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, 100g of polybutylene adipate glycol with a molecular weight of 2000, 60g of 1,6-hexanediol polycarbonate with a molecular weight of 2000, 35.5g of dihydroxyl-terminated long-chain alkyl silicone oil IOTA-8865H (Anhui Aiyota Silicone Oil Co., Ltd.) with a molecular weight of 3550, and 32.6g of hydroxyl-terminated methyl vinyl silicone oil IOTA. The following ingredients were used: 1203V (Anhui Aiyota Silicone Oil Co., Ltd., hydroxyl content ≥6%, vinyl content: 6.5~7.5mol%), 4g of antioxidant BHT, 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent S-3313. The resulting TPU granules had a Shore hardness of 45A, a glass transition temperature of -60℃, a tensile strength of 8.49MPa, and an elongation at break of 1032%.

[0115] The difference between Example 40 and Example 39 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 84 parts of filler composition, 276 parts of co-solvent - toluene, and 60 parts of acetone. The crosslinking agent is composed of α-dibenzocyclooctylene-ω-maleimide polyethylene glycol (molecular weight 676.76), α-biotin-ω-maleimide polyethylene glycol (molecular weight 3500), three-arm polyethylene glycol thiols (molecular weight 2000), and four-arm polyethylene glycol thiols (molecular weight 5000) in a mass ratio of 2:2:2.1:2.1. The filler composition is composed of carbon black, worm graphite, carbon fiber, graphene, boron nitride nanosheets, and silicon carbide whiskers in a mass ratio of 90:5:3:0.5:0.5:1. The butyl rubber composition comprises 32 parts butyl rubber, 6 parts ethylene propylene diene monomer (EPDM) rubber, 3 parts hydroxyl-terminated polybutadiene with a molecular weight of 3000, 0.123 parts azobisisobutyronitrile (AIBN), 0.123 parts potassium persulfate, 0.205 parts single-atom zinc-doped carbon black, 1.025 parts sulfur, 1.025 parts N-cyclohexyl-2-benzothiazole sulfenamide, 0.1025 parts zinc dibutyldithiocarbamate, 1.64 parts silane coupling agent KH-570, 0.41 parts titanate coupling agent KR 238S, 0.5125 parts nano-silicon nitride, 0.5125 parts nano-silica, 1.025 parts 2,4-dimethyl-6-tert-butylphenol, and 4.1 parts softener dibutyl ester.

[0116] The difference between Comparative Example 1 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 80 parts of butyl rubber composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 320 parts of cosolvent - toluene.

[0117] The difference between Comparative Example 2 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 70 parts of butyl rubber composition, 10 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 320 parts of cosolvent - toluene.

[0118] The difference between Comparative Example 3 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 35 parts of butyl rubber composition, 45 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 320 parts of cosolvent - toluene.

[0119] The difference between Comparative Example 4 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 80 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 320 parts of cosolvent - toluene.

[0120] The difference between Comparative Example 5 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 200 parts of cosolvent - toluene.

[0121] The difference between Comparative Example 6 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 430 parts of cosolvent - toluene.

[0122] The difference between Comparative Example 7 and Example 4 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 84 parts of filler composition, and 220 parts of cosolvent - toluene.

[0123] The difference between Comparative Example 8 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 50 parts of filler composition, and 268 parts of cosolvent - toluene.

[0124] The difference between Comparative Example 9 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 2.65 parts of crosslinking agent, 125 parts of filler composition, and 418 parts of cosolvent - toluene.

[0125] The difference between Comparative Example 10 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 84 parts of filler composition, and 336 parts of cosolvent - toluene.

[0126] The difference between Comparative Example 11 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 0.5 parts of crosslinking agent, 84 parts of filler composition, and 336 parts of cosolvent - toluene.

[0127] The difference between Comparative Example 12 and Example 1 is that the capping body of a hot melt adhesive cap that bonds well with PVC coating is made from the following raw materials in parts by weight: 50 parts of butyl rubber composition, 34 parts of polyurethane elastomer composition, 5 parts of crosslinking agent, 84 parts of filler composition, and 336 parts of cosolvent - toluene.

[0128] The difference between Comparative Example 13 and Example 1 is that the filler composition is composed of carbon black and calcium carbonate (1250 mesh light calcium carbonate, brand Yongshun, magnesium oxide content 34.2%, grade 1) in a mass ratio of 75:25.

[0129] The difference between Comparative Example 14 and Example 1 is that the filler composition is composed of carbon black and flake graphite (2000 mesh flake microcrystalline graphite, brand Zhengxu) in a mass ratio of 75:25.

[0130] The difference between Comparative Example 15 and Example 1 is that the filler composition is composed of carbon black and worm graphite in a mass ratio of 75:25.

[0131] The difference between Comparative Example 16 and Example 1 is that the butyl rubber composition consists of 40 parts butyl rubber, 0.12 parts azobisisobutyronitrile, 0.12 parts potassium persulfate, 0.2 parts single-atom zinc-doped carbon black (custom-made by Liankehua), 1 part sulfur, 1 part N-cyclohexyl-2-benzothiazole sulfenamide, 0.1 parts zinc dibutyldithiocarbamate, 1.6 parts silane coupling agent KH-570, 0.4 parts titanate coupling agent KR 238S, 0.5 parts nano silicon nitride, 0.5 parts nano silica, 1 part 2,4-dimethyl-6-tert-butylphenol, and 4 parts softener - dibutyl ester.

[0132] The difference between Comparative Example 17 and Example 1 is that the butyl rubber composition consists of 32 parts butyl rubber, 8 parts EPDM rubber, 0.12 parts azobisisobutyronitrile, 0.12 parts potassium persulfate, 0.2 parts single-atom zinc-doped carbon black (custom-made by Liankehua), 1 part sulfur, 1 part N-cyclohexyl-2-benzothiazole sulfenamide, 0.1 parts zinc dibutyldithiocarbamate, 1.6 parts silane coupling agent KH-570, 0.4 parts titanate coupling agent KR 238S, 0.5 parts nano silicon nitride, 0.5 parts nano silica, 1 part 2,4-dimethyl-6-tert-butylphenol, and 4 parts softener - dibutyl ester.

[0133] The difference between Comparative Example 18 and Example 1 is that the butyl rubber composition consists of 37 parts butyl rubber, 3 parts hydroxyl-terminated polybutadiene with a molecular weight of 3000, 0.12 parts azobisisobutyronitrile, 0.12 parts potassium persulfate, 0.2 parts monoatomic zinc-doped carbon black (custom-made by Liankehua), 1 part sulfur, 1 part N-cyclohexyl-2-benzothiazole sulfenamide, 0.1 parts zinc dibutyldithiocarbamate, 1.6 parts silane coupling agent KH-570, 0.4 parts titanate coupling agent KR 238S, 0.5 parts nano silicon nitride, 0.5 parts nano silica, 1 part 2,4-dimethyl-6-tert-butylphenol, and 4 parts softener - dibutyl ester.

[0134] Performance Testing: 1. Peel Strength Test Method: Sample Preparation: The finished hot melt adhesive plugs from Examples 1-40 and Comparative Examples 1-18 were coated with SA1062 / 7 automotive anti-stone chip coating (hereinafter referred to as PVC coating resin). The coating was applied using a scraping method, with the automotive-grade PVC coating resin scraped onto the surface of the finished hot melt adhesive plug at room temperature. The plugs were then cured in an oven at 170℃ for 10 minutes to form a 500±20 micrometer PVC coating. The peel strength was then measured according to QB / T 4042-2010 Polyvinyl Chloride Coated Film Material 5.7. 2. Mechanical Properties (Tensile Properties and Tear Strength) Test Method: Dumbbell-shaped specimens were prepared according to the preparation methods for the finished hot melt adhesive plugs from Examples 1-40 and Comparative Examples 1-18. The dumbbell-shaped specimens were tested using an AI-3000 electronic universal testing machine according to GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". 3. Softening Point Test Method: Following the preparation methods for the finished hot melt adhesive caps in Examples 1-40 and Comparative Examples 1-18, dumbbell-shaped specimens were prepared. Threads were tied to both ends of the dumbbell-shaped specimens, with one paperclip attached to one end and three paperclips to the other. The dumbbell-shaped specimens were then hung in an oven, with one paperclip hanging above and three paperclips hanging below. The oven was turned on, and the temperature was recorded when the lower paperclip touched the bottom of the oven; this temperature is the softening point temperature of the finished hot melt adhesive cap material. 4. High-Frequency Damping Performance Test: According to ASTM E 756, the high-frequency damping performance of the samples was tested on a VBT-Oberst vibration beam turntable testing system. Samples were prepared according to the preparation methods for the finished hot melt adhesive caps in Examples 1-40 and Comparative Examples 1-18. The total thickness of the samples was 2.0 mm, the width was 12.5 mm, and the length was 215 mm. Specifically, the sample, cut to the correct size, has its release paper removed and is attached to a steel strip 1mm thick, 12.5mm wide, and 241mm long. The steel strip with the sample attached is clamped vertically at one end, and the steel strip is excited to vibrate at an excitation frequency of 1–1000 Hz using a non-contact electromagnetic exciter located near the free end. The response of the steel strip to various frequency excitations is measured using appropriately positioned sensors, and the vibration amplitude of the test sample is detected. Damping performance is represented by the loss coefficient. When the loss coefficient of the sample under 1000 Hz high-frequency excitation is not less than 0.1, it is considered to meet the application requirements. The temperature range where tanδ ≥ 0.1 is recorded.

[0135] Table 1: Test parameters of finished hot melt adhesive plugs in Examples 1-4 and Comparative Examples 1-4

[0136]

[0137] Based on Examples 1-4 and Comparative Examples 1-4 and Table 1, it can be seen that the mass ratio of butyl rubber composition to self-made polyurethane elastomer composition is preferably controlled at (40-60):(25-40) to ensure that the finished hot melt adhesive plug has good mechanical properties and damping performance. Preferably, the mass ratio of butyl rubber composition to polyurethane elastomer composition is 50 / 34.

[0138] Based on Examples 1-4 and Comparative Example 4, and in conjunction with Table 1, it can be seen that the self-made polyurethane elastomer composition has relatively better damping performance, but its production cost is relatively high and its commercial production economy is relatively low. Therefore, using a butyl rubber composition and a self-made polyurethane elastomer composition to form a finished hot melt adhesive plug is more cost-effective and has better overall mechanical properties.

[0139] Table 2: Test parameters for finished hot melt adhesive plugs in Examples 1, 4-8 and Comparative Examples 5-7

[0140]

[0141] Based on Examples 1, 4-8, and Comparative Examples 5-7, and referring to Table 2, it can be seen that the amount of co-solvent added has a significant impact on the mechanical properties and damping performance of the prepared hot melt adhesive capping body. This is mainly because the amount of co-solvent added affects the distribution of filler in the finished hot melt adhesive capping body and the distribution of TPU molecular chains throughout the entire IPN structure. Preferably, the amount of co-solvent added is approximately twice the total mass of the butyl rubber composition + polyurethane elastomer composition + filler composition.

[0142] Combined with Examples 1, 4-8 and Comparative Examples 5-7 and Table 2, it can be seen that the mechanical properties and damping performance of the hot melt adhesive plug prepared by using toluene and acetone as a co-solvent in Example 8 are improved. That is, the hot melt adhesive plug prepared by the preparation method of this application has better overall performance by using toluene as the main co-solvent and acetone as the auxiliary solvent.

[0143] Table 3: Test parameters for finished hot melt adhesive plugs in Examples 4, 9-12 and Comparative Examples 8-9

[0144]

[0145] Combining Examples 4, 9-12, and Comparative Examples 8-9 with Table 3, it can be seen that as the amount of filler composition added increases, the temperature range with tanδ≥0.1 shifts towards higher temperatures. This is mainly because excessive filler composition affects the molecular chain, leading to a decrease in its damping performance at low temperatures and a decrease in its adhesion to PVC coatings. Conversely, insufficient filler composition results in a relatively significant decrease in its softening point temperature, thus affecting the overall heat resistance. Therefore, the amount of filler composition added can be controlled between 60-120 parts, and the amount of filler composition obtained in the experiment can be controlled between 80-90 parts. The optimal solution is that the mass of the butyl rubber composition + polyurethane elastomer composition equals the mass of the filler composition.

[0146] Table 4: Test parameters for finished hot melt adhesive plugs in Examples 4, 13-18 and Comparative Examples 10-12

[0147]

[0148] Based on Examples 4, 13-14 and Comparative Examples 10-12, and in conjunction with Table 4, it can be seen that the compounded crosslinking agent affects the crosslinking density of the three-dimensional network structure of the prepared hot melt adhesive plug. The crosslinking agent content measured in the experiment is preferably controlled at 1-4 parts. Considering the specific formulation, the ratio of the filler content of the crosslinking agent to the total mass of the butyl rubber composition + polyurethane elastomer composition is preferably 1:(30-32), which can ensure that the prepared hot melt adhesive plug has both good mechanical strength and heat resistance as well as good damping performance.

[0149] As can be seen from Examples 4, 13-18 and Comparative Examples 10-12, and Table 4, the crosslinking agent formed by the polyether containing maleimide groups, namely α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 500-1000 and / or α-biotin-ω-maleimide polyethylene glycol with a molecular weight of 2000-5000, combined with thiol-terminated multi-walled polyethers with a molecular weight of 2000-5000, namely three-arm polyethylene glycol thiols and / or four-arm polyethylene glycol thiols, affects the mechanical properties and high-frequency damping coefficient of the finished hot melt adhesive cap. It can be customized according to the customer's requirements for the mechanical properties and high-frequency damping coefficient of the hot melt adhesive cap.

[0150] Table 5: Test parameters for finished hot melt adhesive plugs in Examples 4, 19-25 and Comparative Examples 13-15

[0151]

[0152] Combined with Examples 4, 19-25 and Comparative Examples 13-15 and Table 5, it can be seen that, compared with Comparative Example 15, using worm graphite as one of the components of the filler composition has a positive effect on the tensile properties and damping performance of the finished hot melt adhesive plug.

[0153] Combined with Examples 4, 19-25, and Comparative Examples 13-15, and referring to Table 5, it can be seen that a filler composition consisting of at least one of carbon black, silica, and flake graphite, combined with at least one of montmorillonite, titanium dioxide, carbon fiber, boron nitride nanosheets, graphene, halloysite nanosheets, carbon nanotubes, silicon carbide whiskers, and aramid fiber, can improve the mechanical properties, heat resistance, and damping performance of the finished hot melt adhesive plug. Preferably, the filler composition is made from the following raw materials in the following mass percentages: 5-10 wt% ≥800 mesh flake graphite, 0.5-3 wt% carbon nanofibers, 0.5-3 wt% boron nitride nanosheets, 0.5-3 wt% graphene, 0.2-1.0 wt% silicon carbide whiskers, with the balance being carbon black. Based on the above filler composition formulation, the overall comprehensive performance can be improved.

[0154] Table 6: Test parameters for finished hot melt adhesive plugging in Examples 4, 26-30 and Comparative Examples 16-18

[0155]

[0156] Combined with Examples 4, 26-30, and Comparative Examples 16-18, and with Table 6, it can be seen that a butyl rubber composition consisting of 30-40 parts of butyl rubber, 5-10 parts of ethylene propylene rubber, and 2-8 parts of hydroxyl-terminated polybutadiene with a molecular weight of 2000-4500 can improve the tensile properties and heat resistance of the finished hot melt adhesive plug, while also having good damping and shock absorption properties.

[0157] Table 7: Test parameters for finished hot melt adhesive plugging in Examples 4 and 31-40

[0158]

[0159] Combining Examples 4 and 31-40 with Table 7, it can be seen that controlling the hard short content and R-value of TPU can improve the hardness, tensile properties, and Tg temperature of the prepared TPU. This also improves the mechanical properties, heat resistance, low-temperature flexibility, and damping performance of the hot melt adhesive plugs prepared using the aforementioned TPU resin. The specific TPU resin selection should be customized according to the specific performance requirements of automotive customers to obtain hot melt adhesive plug products that balance performance and economy.

[0160] The difference between Example 41 and Example 1 is as follows: In step four, the obtained mixture is injected into a molding mold, heated to 115°C, and vacuumed to a molding pressure of 0.06-0.062 MPa to remove the co-solvent. The mold is then sealed using a molding plate. The surface of the molding plate is finely micro-engraved with multiple irregularly shaped protrusions, each protrusion being cap-shaped. The handle of a single cap-shaped protrusion is 15 micrometers long and 5 micrometers in diameter. The cap shape of the cap-shaped protrusion is conical, 5 micrometers long and 10 micrometers in diameter. The molded die is placed in a vacuum autoclave and pressurized with nitrogen to 3 MPa. It is then heated to 148°C for a secondary vulcanization treatment for 12 minutes. Afterward, it is cooled to 85°C at a rate of 2°C / min and held for 30 minutes. The pressure is then released to atmospheric pressure and allowed to cool naturally to room temperature to obtain the cap body. Hot melt adhesive is then filled into the hot melt adhesive filling area of ​​the cap body to obtain the finished hot melt adhesive cap. The peel strength between the finished hot melt adhesive cap and the PVC coating is 218.7 N / 5cm, which is 15.4% higher than the peel strength, further enhancing the bonding stability.

[0161] In summary, the hot melt adhesive plug prepared in this application is installed on the sheet metal hole and then baked with PVC undercoat paint (150-180℃), intermediate coat and topcoat (140-170℃). The hot melt adhesive plug has good bonding stability with the PVC paint and good thermal stability, ensuring good overall vibration damping and sound absorption performance. In addition, the hot melt adhesive plug has a wide damping temperature range, that is, it has good damping and vibration damping performance and sound absorption and noise reduction performance at low temperatures.

Claims

1. A hot melt adhesive plug that bonds well with PVC coatings, characterized in that: The hot melt adhesive plug includes a plug body (1) and a hot melt adhesive layer (2). The plug body (1) includes a plug cap (11) and a plug pin (12) integrally formed on the lower surface of the plug cap (11). The plug cap (11) is bent downward to form a plug cap edge. An annular sleeve (13) is integrally formed on the outer periphery of one end of the plug pin (12) facing away from the plug body (1). A hot melt adhesive filling area (20) is formed on the lower surface of the plug cap edge, the outer periphery of the plug pin (12), and the annular sleeve (13). The hot melt adhesive layer (2) fills the hot melt adhesive filling area (20) and is flush with the upper surface of the annular sleeve (13). The lower surface of the plug cap is integrally formed with a first grid-shaped adhesive texture, and the outer surface of the plug cap post (12) without the annular sleeve (13) is integrally formed with a second grid-shaped adhesive texture; the upper surface of the annular sleeve (13) is integrally formed with a third grid-shaped adhesive texture; the upper surface of the plug cap (11) combined with the PVC coating is molded and imprinted with several mutually spaced irregularly shaped adhesive grooves; the irregularly shaped adhesive grooves are one of the following: inverted umbrella shape, inverted cap shape, and inverted mushroom shape; The plug cover (1) is made from the following raw materials in parts by weight: 40 parts of butyl rubber composition, 40 parts of polyurethane elastomer composition, 2.5 parts of crosslinking agent, 80 parts of filler composition, and 320 parts of cosolvent-toluene; The crosslinking agent is composed of α-dibenzocyclooctyn-ω-maleimide polyethylene glycol with a molecular weight of 676.76, three-arm polyethylene glycol thiols with a molecular weight of 2000, and carbon black additive with surface-loaded aluminum chloride in a mass ratio of 1:1.05:0.

1. The preparation method of the carbon black additive with surface-loaded aluminum chloride is as follows: 10g of carbon black and 1g of aluminum chloride are placed in a planetary ball mill and subjected to dry high-speed ball milling under nitrogen protection at a ball milling speed of 2400 rpm for 30 min, followed by cooling to obtain the product. The filler composition is composed of carbon black, worm graphite, carbon fiber, and graphene in a mass ratio of 90:7:2:

1. The butyl rubber composition comprises 32 parts butyl rubber, 5 parts ethylene propylene diene monomer (EPDM) rubber, 3 parts hydroxyl-terminated polybutadiene, 0.12 parts azobisisobutyronitrile (AIBN), 0.12 parts potassium persulfate, 0.2 parts single-atom zinc-doped carbon black, 1 part sulfur, 1 part N-cyclohexyl-2-benzothiazole sulfenamide, 0.1 parts zinc dibutyl dithiocarbamate, 1.6 parts silane coupling agent KH-570, 0.4 parts titanate coupling agent KR 238S, 0.5 parts nano-silicon nitride, 0.5 parts nano-silica, 1 part 2,4-dimethyl-6-tert-butylphenol, and 4 parts softener dibutyl ester. The polyurethane elastomer composition is formulated as follows: 114.37g of hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), 94.54g of 3-methyl-1,5-pentanediol, 330g of polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, 100g of polybutylene adipate diol with a molecular weight of 2000, 60g of 1,6-hexanediol polycarbonate with a molecular weight of 2000, 30g of hydroxyl-terminated polybutadiene (HTPB) with a molecular weight of 3000, 4g of antioxidant (BHT), 0.8g of bismuth carboxylate, 5g of zinc stearate, and 3g of leveling agent (S-3313). The preparation method of the polyurethane elastomer composition is as follows: First, polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000, polybutylene adipate glycol (PEA) with a molecular weight of 2000, and 1,6-hexanediol polycarbonate (PPD) with a molecular weight of 2000 are vacuum dehydrated at 110°C for 2 hours; then, 94.54 g of 3-methyl-1,5-pentanediol is fed into the first feed trough of a twin-screw extruder, and 330 g of accurately metered polytetramethylene ether glycol (PTMEG) with a molecular weight of 3000 is added. PTMEG glycol, 100g of 2000 molecular weight polybutylene adipate diol, 60g of 2000 molecular weight 1,6-hexanediol polyphenyl carbonate, and 30g of 3000 molecular weight hydroxyl-terminated polybutadiene HTPB are fed into the second feed trough of a twin-screw extruder. Simultaneously, 114.37g of accurately measured hexamethylene diisocyanate (HDI), 80.08g of diphenylmethane-4,4'-diisocyanate (MDI), and 0.8g of caprylic / capric acid are added. Bismuth, 3g of leveling agent S-3313, 4g of antioxidant BHT, and 5g of zinc stearate are mixed evenly and then added to the third feed trough of a twin-screw extruder. The twin-screw extruder has a 16-stage barrel. The temperatures of the first to sixteenth barrel stages are set as follows: 170℃, 175℃, 180℃, 185℃, 190℃, 190℃, 180℃, 170℃, 165℃, 160℃, 160℃, 160℃, 155℃, 155℃. The liquid material after melting and reacting at 155℃ and 150℃ is discharged from the extruder by a gear pump, granulated by water cooling, and dried in a fluidized bed dryer at 85℃ until the water content is <0.025% to obtain granules. The obtained granules are transferred to an oven and heat-conditioned at 80℃ for 24 hours to eliminate internal stress, thus obtaining TPU granules with a Shore hardness of 40A. The glass transition temperature of the obtained TPU granules is -62℃, the tensile strength is 7.85MPa, and the elongation at break is 1135%. A method for preparing a hot melt adhesive cap that bonds well with PVC coatings, comprising the following steps: Step 1: Carbon black, worm graphite, carbon fiber, and graphene are mixed in a mass ratio of 90:7:2:1 to form a filler. 100g of the resulting filler is then dry-mixed with 4g of KH-570 and 1g of titanate coupling agent KR 238S for 30min to obtain the finished filler composition. 40 parts of accurately measured butyl rubber composition and 50 parts of finished filler composition were subjected to intensive mixing and open milling, and then left to stand for 24 hours to obtain a compound. The butyl rubber composition was prepared from butyl rubber, EPDM rubber, hydroxyl-terminated polybutadiene with a molecular weight of 3000, azobisisobutyronitrile, potassium persulfate, zinc-doped carbon black, sulfur, N-cyclohexyl-2-benzothiazole sulfenamide, zinc dibutyl dithiocarbamate, silane coupling agent KH-570, titanate coupling agent KR 238S, nano-silicon nitride, nano-silica, 2,4-dimethyl-6-tert-butylphenol, and softener dibutyl ester. The obtained compound was extruded, calendered, cooled, and cut into samples to obtain preforms. The preforms were left to stand at room temperature for 12 hours and then vulcanized for 200 seconds at a vulcanization temperature of 145℃ and a vulcanization pressure of 140 kg / cm². 2 Pre-made butyl rubber sheets can be obtained; Step 2: The obtained pre-prepared butyl rubber is swollen in 220 parts of the co-solvent - toluene and mixed well to obtain a butyl rubber swelling solution; Simultaneously, 40 parts of the polyurethane elastomer composition were swollen in the remaining 100 parts of the co-solvent and mixed evenly to obtain a semi-finished TPU swelling solution. The remaining 30 parts of the finished filler composition were added to the obtained TPU swelling solution and stirred evenly. Then, 2.5 parts of accurately measured crosslinking agent were added to obtain the TPU swelling solution. The solution was ultrasonically dispersed for 20 minutes at a power of 600W and a frequency of 40kHz to obtain the finished TPU swelling solution. Step 3: Perform ultrasonic dispersion treatment on the butyl rubber swelling liquid for 5 minutes at a power of 600W and a frequency of 40kHz. Under ultrasonic dispersion, add the finished TPU swelling liquid to the butyl rubber swelling liquid at an addition rate of 2g / min. After the addition is completed, continue ultrasonic dispersion treatment for 8 minutes to obtain a mixture. Step 4: Inject the obtained mixture into the molding mold, heat to 115℃, evacuate to a molding pressure of 0.06-0.062MPa to remove the co-solvent, then pressurize with nitrogen to 3MPa, heat to 148℃ for secondary vulcanization treatment for 12min, then cool down to 85℃ at 2℃ / min and hold for 30min, depressurize to normal pressure, and allow to cool naturally to room temperature to obtain the cap body. Fill the hot melt adhesive filling area of ​​the cap body with hot melt adhesive to obtain the finished hot melt adhesive cap. The hot melt adhesive is automotive hot melt adhesive 8160M, with a hardness of 55±5D, a softening point of 160℃±5℃, a curing speed of 2~6s, a glass transition temperature of -30℃, and a tensile strength of ≥11.3MPa. It is manufactured by Guangdong Shuntian New Materials Co., Ltd.

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