High-thermal-stability high-adhesion EVA hot-melt adhesive and preparation method thereof
By modifying the surface of serpentine with macromolecular substances to prepare modified fillers, a three-dimensional cross-linked network is formed, which solves the problems of insufficient bonding reliability of EVA hot melt adhesive at high temperatures and insufficient bonding performance of porous materials, and achieves high thermal stability and strong bonding effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DONGGUAN CO MO ADHESIVES CO LTD
- Filing Date
- 2026-04-20
- Publication Date
- 2026-06-19
AI Technical Summary
Traditional EVA hot melt adhesives have poor bonding reliability in high-temperature environments, and their bonding performance on porous materials is gradually failing to meet the requirements.
Serpentine-modified fillers were prepared by modifying the surface of serpentine with macromolecular substances having alternating linkage structures, and then mixed with ethylene-vinyl acetate copolymer to form a three-dimensional micro cross-linked network, thereby improving interfacial compatibility and thermal stability.
It improves the heat resistance and adhesion properties of hot melt adhesives, and enhances the bonding strength at high temperatures and the bonding effect on porous materials.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of hot melt adhesive technology, specifically to a thermally stable, high-adhesion EVA hot melt adhesive and its preparation method. Background Technology
[0002] Ethylene-vinyl acetate copolymer (EVA) hot melt adhesive is a solvent-free, 100% solids thermoplastic adhesive. Due to its advantages such as fast curing speed, no pollution, ease of use, and suitability for automated production lines, it is widely used in packaging, bookbinding, shoe material processing, electronics, and furniture edge banding. However, as downstream applications become more sophisticated, especially in demanding applications such as automotive interiors, electronic component potting, and photovoltaic module encapsulation, traditional EVA hot melt adhesives are no longer sufficient to meet the requirements.
[0003] Because EVA resin is a linear polymer with a linear molecular chain structure and a lack of chemical cross-linking points, when the ambient temperature rises to the melting temperature of EVA, the physical cross-linking points between the polymer molecular chains will rapidly disintegrate, leading to a sharp decrease in the cohesive strength of the adhesive layer and even melt flow. This limits the bonding reliability of EVA hot melt adhesives in high-temperature environments. Furthermore, although EVA hot melt adhesives exhibit good wettability to porous materials such as paper and wood, their bonding performance is gradually failing to meet current demands given the continuous development of materials science.
[0004] To address the aforementioned issues, developing an EVA hot melt adhesive with high thermal stability and high bonding strength is a technical challenge that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0005] In order to solve the problems mentioned in the background art, the purpose of this invention is to provide a thermally stable, highly adhesive EVA hot melt adhesive and its preparation method.
[0006] The objective of this invention can be achieved through the following technical solutions: A thermally stable, high-adhesion EVA hot melt adhesive, comprising the following raw materials measured in parts by weight: Ethylene-vinyl acetate copolymer: 65-74 parts; Compatibilizer: 5-12 parts; Tackifier: 10-15 parts; Fischer-Tropsch wax: 12-15 parts; Serpentine modified filler: 1.8-5.6 parts; Antioxidant: 0.5-1 part; The serpentine-modified filler is prepared by modifying the surface of serpentine with macromolecular modifiers.
[0007] As a further aspect of the present invention, the compatibilizer is maleic anhydride-grafted EVA; the tackifier is any one of terpene resin, petroleum resin or rosin resin.
[0008] As a further aspect of the present invention, the preparation method of the serpentine modified filler includes the following steps: Step 1: Surface modification of serpentine In an ethanol-water solution medium, serpentine was surface-modified using an epoxide silane coupling agent to obtain organically modified serpentine. Step 2: Preparation of serpentine-modified filler Organically modified serpentine and organic solvent were added to a nitrogen-filled reactor and dispersed until a uniform dispersion was formed. Then, an intermediate linker and catalyst were added to the dispersion under stirring. After the addition was complete, heating was turned on and the temperature was raised to 75-85℃. The mixture was kept at this temperature and stirred for 4-8 hours. Then, 2,2-bis(4-hydroxyphenyl)adamantane diglycidyl ether was added to the reactor and the temperature was adjusted to 90-100℃. The mixture was kept at this temperature and stirred for 12-18 hours. The nitrogen gas was then removed and the solid product was separated after natural cooling to obtain the serpentine modified filler.
[0009] As a further aspect of the present invention, in step one, the volume fraction of the ethanol aqueous solution is 60-90%.
[0010] As a further aspect of the present invention, in step one, the epoxide coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane or 3-glycidyl etheroxypropyltriethoxysilane.
[0011] As a further aspect of the present invention, in step two, the organic solvent is any one of dimethyl sulfoxide, N,N-dimethylformamide, or N,N-dimethylacetamide.
[0012] As a further aspect of the present invention, in step two, the intermediate linker is any one of 4,4'-sulfonyl dibenzoic acid, 1,4-bis(2-carboxyethyl)piperazine, or piperazine-1,4-diacetic acid.
[0013] As a further aspect of the present invention, in step two, the catalyst is any one of tetrabutylammonium bromide, tetramethylammonium bromide, tetrabutylammonium hydrogen sulfate, or N,N-dimethylbenzylamine.
[0014] It should be noted that in the above technical solution, serpentine is first modified by using an epoxide silane coupling agent to carry epoxy functional groups on the serpentine surface, thus obtaining organically modified serpentine. Then, under the action of a catalyst, the active epoxy substituents of the organically modified serpentine undergo ring-opening esterification with the active carboxyl substituents at one end of the intermediate linker structure. Subsequently, the active carboxyl substituents at the other end of its structure further undergo ring-opening esterification with the active epoxy substituents of 2,2-di(4-hydroxyphenyl)adamantane diglycidyl ether. As a result, a large amount of serpentine in the system can be used as the initiation site for in-situ ring-opening esterification polymerization on the serpentine surface, using the epoxy substituents of the organically modified serpentine as the initiation site and the intermediate linker and 2,2-di(4-hydroxyphenyl)adamantane diglycidyl ether as polymerizing monomers. This allows for the modification of the serpentine surface with a macromolecular substance having an alternating linkage structure, thus obtaining serpentine modified filler.
[0015] As a further aspect of the present invention, the antioxidant is any one of antioxidant 1010, antioxidant 1076, or antioxidant 168.
[0016] A method for preparing a thermally stable, high-adhesion EVA hot melt adhesive includes the following steps: Step 1: Mix the ethylene-vinyl acetate copolymer and serpentine modified filler at a temperature of 160-170℃ and stir until homogeneous to form a pre-mixing material; The second step is to add compatibilizer, tackifier, Fischer-Tropsch wax and antioxidant to the pre-mixed material, continue stirring until a uniform material is formed, cool down and discharge the material to obtain EVA hot melt adhesive.
[0017] The beneficial effects of this invention are: This invention modifies the surface of serpentine with a macromolecular substance having an alternating linkage structure as an additive. On the one hand, the large number of hydroxyl substituents in the macromolecular substance structure, generated by the ring-opening esterification reaction, can interact with the anhydride groups of the compatibilizer during subsequent heating and melting. Therefore, a three-dimensional micro cross-linked network can be formed at the interface between serpentine and ethylene-vinyl acetate copolymer. This cross-linked network can greatly improve the interfacial compatibility between serpentine and ethylene-vinyl acetate copolymer, and promote the more uniform dispersion of serpentine in the hot melt adhesive. Since serpentine has a layered structure, uniform dispersion will form a flat continuous barrier layer in the hot melt adhesive, which can effectively prevent the escape of thermal decomposition products, thereby improving the heat resistance stability of the hot melt adhesive. On the other hand, the macromolecules contain abundant rigid ring structures, which enter the molecular chain of ethylene-vinyl acetate copolymer through a three-dimensional network, thereby further improving the heat resistance stability of the hot melt adhesive. In addition, the macromolecules also contain abundant ether bonds and hydroxyl groups, which can form hydrogen bonds with the adhered objects, thereby effectively improving the bonding performance of the hot melt adhesive.
[0018] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation
[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0020] Example 1 A thermally stable, high-adhesion EVA hot melt adhesive, comprising the following raw materials measured in parts by weight: Ethylene-vinyl acetate copolymer: 65 parts; Maleic anhydride-grafted EVA: 5 parts; Terpene resin: 10 parts; Fischer-Tropsch wax: 12 parts; Serpentine modified filler: 1.8 parts; Antioxidant 1010: 0.5 parts; The preparation method of the EVA hot melt adhesive includes the following steps: Step 1: Mix the ethylene-vinyl acetate copolymer and serpentine modified filler at a temperature of 160℃ and stir until homogeneous to form a pre-mixing material; The second step involves adding maleic anhydride-grafted EVA, terpene resin, Fischer-Tropsch wax, and antioxidant 1010 to the pre-mixed material. After stirring until a uniform material is formed, the material is cooled and discharged to obtain EVA hot melt adhesive.
[0021] The melt index of the ethylene-vinyl acetate copolymer is 150 d / min, and the VA content is 28 wt%; the following are the same.
[0022] The preparation method of serpentine-modified filler includes the following steps: Step 1: Surface modification of serpentine 1.8g of serpentine was dispersed in a 70% ethanol aqueous solution, followed by the addition of 0.5g of 3-glycidyl etheroxypropyltrimethoxysilane. After the addition was complete, the mixture was stirred and mixed. The pH was adjusted to 4, and the temperature was raised to 70℃. The mixture was kept at this temperature and stirred for 8 hours. The heating was then stopped, the material was cooled and discharged, the solid material was centrifuged, washed, and vacuum dried to obtain organic modified serpentine. Step 2: Preparation of serpentine-modified filler 1.5 g of organically modified serpentine and N,N-dimethylformamide were added to a nitrogen-filled reactor and dispersed until a uniform dispersion was formed. Then, under stirring, 0.3 g of 4,4'-sulfonyl dibenzoic acid and 0.1 g of tetrabutylammonium bromide were added to the dispersion. After the addition was complete, the heating was turned on and the temperature was raised to 80 °C. After stirring for 6 h, 0.4 g of 2,2-bis(4-hydroxyphenyl)adamantane diglycidyl ether was added to the reactor and the temperature was adjusted to 100 °C. After stirring for 168 h, the nitrogen was removed and the solid product was separated after natural cooling to obtain the serpentine-modified filler.
[0023] Example 2 A thermally stable, high-adhesion EVA hot melt adhesive, comprising the following raw materials measured in parts by weight: Ethylene-vinyl acetate copolymer: 68 parts; Maleic anhydride-grafted EVA: 10 parts; Rosin resin: 12 parts; Fischer-Tropsch wax: 13 parts; Five parts of serpentine-modified filler; Antioxidant 1076: 0.8 parts; The preparation method of the EVA hot melt adhesive includes the following steps: Step 1: Mix the ethylene-vinyl acetate copolymer and serpentine modified filler at a temperature of 165℃ and stir until homogeneous to form a pre-mixing material; The second step involves adding maleic anhydride-grafted EVA, rosin resin, Fischer-Tropsch wax, and antioxidant 1076 to the pre-mixed material. After stirring until a uniform material is formed, the material is cooled and discharged to obtain EVA hot melt adhesive.
[0024] The preparation method of the serpentine modified filler is the same as that in Example 1.
[0025] Example 3 A thermally stable, high-adhesion EVA hot melt adhesive, comprising the following raw materials measured in parts by weight: Ethylene-vinyl acetate copolymer: 74 parts; Maleic anhydride-grafted EVA: 12 parts; Rosin resin: 15 parts; Fischer-Tropsch wax: 15 parts; Serpentine modified filler: 5.6 parts; Antioxidant 1010: 1 part; The preparation method of the EVA hot melt adhesive includes the following steps: Step 1: Mix the ethylene-vinyl acetate copolymer and serpentine modified filler at a temperature of 170℃ and stir until homogeneous to form a pre-mixing material; The second step involves adding maleic anhydride-grafted EVA, rosin resin, Fischer-Tropsch wax, and antioxidant 1010 to the pre-mixed material. After stirring until a uniform material is formed, the material is cooled and discharged to obtain EVA hot melt adhesive.
[0026] The preparation method of the serpentine modified filler is the same as that in Example 1.
[0027] Comparative Example 1 An EVA hot melt adhesive differs from Example 2 in that the serpentine-modified filler is replaced with unmodified serpentine, while all other aspects are the same.
[0028] Comparative Example 2 An EVA hot melt adhesive differs from Example 2 in that the serpentine-modified filler is removed, while the rest are the same.
[0029] Test case The EVA hot melt adhesive used in the examples and comparative examples was heated to melt and then coated onto a clean steel plate surface. The coating area was controlled at 10cm × 3cm, and the coating thickness was 0.2mm to form a hot melt adhesive film. The following performance tests were then conducted: (1) PC sheet is bonded to the surface of hot melt adhesive film. The pressure is controlled at 2MPa. After hot pressing at 60℃ for 1 hour, the temperature is lowered to room temperature and pressure is maintained for 20 minutes. After fixing with a clamp, the peel strength test is performed using an electronic universal testing machine with the clamp controlled at a rising rate of 200mm / min. (2) Peel the hot melt adhesive film off the steel plate surface and place it in an oven. In a nitrogen atmosphere, raise the temperature from room temperature to 600°C at a heating rate of 10°C / min. Record the temperature at which the adhesive film loses 5% of its thermal weight as the initial decomposition temperature and evaluate its thermal stability. The test results are recorded in Table 1: Table 1 - Test Results Analysis and test results show that the hot melt adhesive prepared in the embodiments of the present invention has good bonding performance and thermal stability. After replacing the serpentine modified filler with unmodified serpentine, the serpentine cannot be effectively dispersed evenly due to interface problems to form a continuous barrier layer. At the same time, it cannot utilize the effect of macromolecular substances, resulting in a significant decrease in all properties of the hot melt adhesive.
[0030] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.
[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A thermally stable, high-adhesion EVA hot melt adhesive, characterized in that, Includes the following raw materials measured in parts by weight: Ethylene-vinyl acetate copolymer: 65-74 parts; Compatibilizer: 5-12 parts; Tackifier: 10-15 parts; Fischer-Tropsch wax: 12-15 parts; Serpentine modified filler: 1.8-5.6 parts; Antioxidant: 0.5-1 part; The serpentine-modified filler is prepared by modifying the surface of serpentine with macromolecular modifiers.
2. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 1, characterized in that, The compatibilizer is maleic anhydride-grafted EVA; the tackifier is any one of terpene resin, petroleum resin or rosin resin.
3. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 1, characterized in that, The preparation method of the serpentine modified filler includes the following steps: Step 1: Surface modification of serpentine In an ethanol-water solution medium, serpentine was surface-modified using an epoxide silane coupling agent to obtain organically modified serpentine. Step 2: Preparation of serpentine-modified filler Organically modified serpentine and organic solvent were added to a nitrogen-filled reactor and dispersed until a uniform dispersion was formed. Then, an intermediate linker and catalyst were added to the dispersion under stirring. After the addition was complete, heating was turned on and the temperature was raised to 75-85℃. The mixture was kept at this temperature and stirred for 4-8 hours. Then, 2,2-bis(4-hydroxyphenyl)adamantane diglycidyl ether was added to the reactor and the temperature was adjusted to 90-100℃. The mixture was kept at this temperature and stirred for 12-18 hours. The nitrogen gas was then removed and the solid product was separated after natural cooling to obtain the serpentine modified filler.
4. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 3, characterized in that, In step one, the volume fraction of the ethanol-water solution is 60-90%.
5. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 3, characterized in that, In step one, the epoxide coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane or 3-glycidyl etheroxypropyltriethoxysilane.
6. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 3, characterized in that, In step two, the organic solvent is any one of dimethyl sulfoxide, N,N-dimethylformamide, or N,N-dimethylacetamide.
7. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 3, characterized in that, In step two, the intermediate linker is any one of 4,4'-sulfonyl dibenzoic acid, 1,4-bis(2-carboxyethyl)piperazine, or piperazine-1,4-diacetic acid.
8. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 3, characterized in that, In step two, the catalyst is any one of tetrabutylammonium bromide, tetramethylammonium bromide, tetrabutylammonium hydrogen sulfate, or N,N-dimethylbenzylamine.
9. The thermally stable, high-adhesion EVA hot melt adhesive according to claim 1, characterized in that, The antioxidant is any one of antioxidant 1010, antioxidant 1076, or antioxidant 168.
10. A method for preparing a thermally stable, high-adhesion EVA hot melt adhesive as described in claim 1, characterized in that, Includes the following steps: Step 1: Mix the ethylene-vinyl acetate copolymer and serpentine modified filler at a temperature of 160-170℃ and stir until homogeneous to form a pre-mixing material; The second step is to add compatibilizer, tackifier, Fischer-Tropsch wax and antioxidant to the pre-mixed material, continue stirring until a uniform material is formed, cool down and discharge the material to obtain EVA hot melt adhesive.