Composite modified hot melt adhesive film and preparation method thereof

Abstract

The invention discloses a composite modified hot melt adhesive film and a preparation method thereof, and belongs to the technical field of hot melt adhesive films. The composite modified hot melt adhesive film is prepared from the following raw materials in parts by weight: 70 to 80 parts of ethylene-vinyl acetate copolymer, 10 to 20 parts of nitrile rubber, 10 to 20 parts of inorganic filler, 10 to 20 parts of flexibilizer, 5 to 15 parts of tackifying resin, 3 to 10 parts of compatilizer, 1 to 3 parts of coupling agent, 0.5 to 1.5 parts of assistant and 0.01 to 0.1 part of initiator. The auxiliary agent containing the triazine structure and the hindered phenol structure has good compatibility with other raw materials, and the auxiliary agent is grafted on the surface of the inorganic filler through the coupling agent under the action of the initiator, so that the stability of the auxiliary agent and the dispersion of the inorganic filler are promoted, and each raw material can exert the own effect to the greatest extent; the hot melt adhesive film is endowed with excellent and stable thermo-oxidative aging resistance, ultraviolet aging resistance, adhesive property, wear resistance and the like.

Description

Technical Field

[0002] The invention belongs to the technical field of hot melt adhesive films, and in particular relates to a composite modified hot melt adhesive film and a preparation method thereof. Background Art

[0004] In recent years, with the booming development of electronic products, construction industry, clothing decoration, footwear industry, automobile, household products and other industries, hot melt adhesive film, as a new type of adhesive, has been widely used due to its strong adhesion, no pollution, easy operation and storage. Hot melt adhesive film is generally prepared from saturated polyolefin materials as the base material, such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer and polyolefin elastomer.

[0005] Nitrile rubber is a commonly used oil-resistant rubber, which is made from butadiene and acrylonitrile by emulsion polymerization. Nitrile rubber is mainly produced by low-temperature emulsion polymerization. It has excellent oil resistance, high wear resistance, good heat resistance and strong adhesion. Using nitrile rubber as the raw material of hot melt adhesive film can increase the wear resistance, heat resistance and adhesion of the hot melt adhesive film.

[0006] In addition, most of the hot melt adhesive films in the prior art have poor anti-aging performance. Under the action of heat, moisture and light, the adhesive strength and cohesive strength decrease significantly, which greatly shortens the service life of the hot melt adhesive film. Therefore, it is urgent to carry out composite modification on the existing hot melt adhesive film so that it has excellent and stable anti-aging performance to meet market demand. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the prior art and provide a composite modified hot melt adhesive film and a preparation method thereof.

[0009] The purpose of the present invention can be achieved through the following technical solutions:

[0010] A composite modified hot melt adhesive film comprises the following raw materials in parts by weight: 70-80 parts of ethylene-vinyl acetate copolymer, 10-20 parts of nitrile rubber, 10-20 parts of inorganic filler, 10-20 parts of toughening agent, 5-15 parts of tackifying resin, 3-10 parts of compatibilizer, 1-3 parts of coupling agent, 0.5-1.5 parts of auxiliary agent and 0.01-0.1 parts of initiator.

[0011] Furthermore, the inorganic filler is one or more of titanium dioxide, talc, calcium carbonate, fumed silica, magnesium hydroxide, and aluminum hydroxide.

[0012] Furthermore, the toughening agent is one or more of ethylene-propylene copolymer, ethylene-octene copolymer, and block copolymer of styrene and butadiene.

[0013] Furthermore, the tackifying resin is one or more of rosin resin, hydrogenated petroleum resin, phenolic terpene resin, and C5 petroleum resin.

[0014] Furthermore, the compatibilizer is one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted styrene-butadiene block copolymer, and styrene-maleic anhydride copolymer.

[0015] Furthermore, the coupling agent is one or more of vinyl trimethoxy silane, vinyl triethoxy silane, 3-(methacryloyloxy)propyl trimethoxy silane, and methacryloxypropyl triethoxy silane.

[0016] Furthermore, the auxiliary agent is prepared by the following steps:

[0017] S1. Add 2-amino-4,6-dichloro-S-triazine, triethylamine and methanol to a dry three-necked flask under nitrogen protection, stir and dissolve, then heat to 60°C, then slowly add 4-bromo-2,6-di-tert-butylphenol, and keep at 60°C for 4 hours after the addition. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain intermediate 1; the amount ratio of 2-amino-4,6-dichloro-S-triazine, 4-bromo-2,6-di-tert-butylphenol, triethylamine and methanol is 16.5g:30.7g:16.7mL:240mL;

[0018] Triethylamine is used as an acid-binding agent, and the molar ratio of 4-bromo-2,6-di-tert-butylphenol and 2-amino-4,6-dichloro-S-triazine is controlled to be 1.05-1.1:1. Then, the -Br of 4-bromo-2,6-di-tert-butylphenol and the -NH2 of 2-amino-4,6-dichloro-S-triazine undergo a nucleophilic substitution reaction. The reaction process is as follows:

[0019]

[0020] S2. Add intermediate 1, triethylamine and dimethyl sulfoxide to a dry three-necked flask under nitrogen protection, stir evenly and heat to 65°C, then slowly add 4-chloro-1-butene, continue to react at 65°C for 4h after the addition is complete, cool to room temperature after the reaction is completed, and distill under reduced pressure to obtain intermediate 2; the amount ratio of intermediate 1, 4-chloro-1-butene, triethylamine and dimethyl sulfoxide is 25.9g:7.7mL:11.7mL:200mL;

[0021] The molar ratio of intermediate 1 and 4-chloro-1-butene is controlled to be 1:1.05-1.1, then -NH- of intermediate 1 and -Cl of 4-chloro-1-butene undergo nucleophilic substitution reaction under triethylamine and heating conditions, and the reaction process is as follows:

[0022]

[0023] S3. In a dry brown three-necked flask under nitrogen protection, add resorcinol, anhydrous aluminum chloride and chloroform in sequence, stir evenly, add intermediate 2, then stir and heat to 115°C, react at 115°C for 12 hours. After the reaction, slowly pour the reaction mixture into ice water, precipitate solid, filter, and recrystallize with 80% methanol aqueous solution to obtain an auxiliary agent; the dosage ratio of intermediate 2, resorcinol, anhydrous aluminum chloride and chloroform is 8.9g:4.2mL:4g:200mL.

[0024] The molar ratio of intermediate 2 to resorcinol is controlled to be 1:2.1-2.4, and intermediate 2 and resorcinol undergo Friedel-Crafts acylation reaction under the catalysis of anhydrous aluminum chloride. The reaction process is as follows:

[0025]

[0026] The additive contains triazine structure and hindered phenol structure. The triazine structure can strongly absorb ultraviolet rays of 280nm-400nm, and has the advantages of high efficiency, high temperature resistance, light color and good compatibility. After absorbing ultraviolet light, the chelate ring formed by the intramolecular hydrogen bond is destroyed to form an unstable high-energy ionic compound, which then releases excess energy to restore the original low-energy stable state, thereby absorbing ultraviolet light. The hindered phenol structure mainly protects the hot melt adhesive film from oxidative damage by capturing free radicals and steric hindrance effects. Therefore, the two structures in the additive work synergistically, giving the additive excellent resistance to thermal oxidation aging and ultraviolet aging, thereby protecting the hot melt adhesive film and extending its service life.

[0027] According to the principle of similar compatibility, the additive containing multiple lipophilic benzene rings has good compatibility with the other raw materials, and the additive can be evenly dispersed in the hot melt adhesive film. The terminal carbon-carbon double bond in the additive can produce a chemical reaction with the carbon-carbon double bond in the coupling agent under the action of the initiator, and then the additive is grafted with the inorganic filler through the coupling agent, which not only promotes the dispersion of the inorganic filler, but also improves the stability of the additive in the hot melt adhesive film. Then the additive can play an anti-aging role for a long time, protect the hot melt adhesive film from damage by heat, humidity and light, stabilize the bonding strength and cohesive strength of the hot melt adhesive film, and extend its service life.

[0028] Furthermore, the initiator is one or more of benzoyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile.

[0029] A method for preparing a composite modified hot melt adhesive film comprises the following steps:

[0030] Weigh each raw material by weight and put all the raw materials into a mixer to mix evenly, then put them into a twin-screw extruder for melt blending, extrusion and pelletizing; finally, the pellets are dried and added to an extrusion casting machine, cast, cooled and shaped to obtain a composite modified hot melt adhesive film.

[0031] The beneficial effects of the present invention are as follows: the auxiliary agent containing a triazine structure and a hindered phenol structure has good compatibility with the other raw materials, and the auxiliary agent is grafted onto the surface of the inorganic filler through a coupling agent under the action of an initiator, which promotes the stability of the auxiliary agent and the dispersion of the inorganic filler, so that each raw material can exert its own role to the maximum extent, giving the hot melt adhesive film excellent and stable resistance to thermal oxidation aging, resistance to ultraviolet aging, bonding performance and wear resistance. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1, preparation of auxiliary agent, the specific steps are as follows:

[0035] S1. Under nitrogen protection, add 16.5 g of 2-amino-4,6-dichloro-S-triazine, 16.7 mL of triethylamine and 240 mL of methanol to a 500 mL dry three-necked flask, stir to dissolve and then heat to 60°C, then slowly add 30.7 g of 4-bromo-2,6-di-tert-butylphenol, keep warm at 60°C for 4 h after the addition is complete, cool to room temperature after the reaction is completed, and distill under reduced pressure to obtain intermediate 1;

[0036] S2. Under nitrogen protection, add 25.9 g of intermediate 1, 11.7 mL of triethylamine and 200 mL of dimethyl sulfoxide to a 500 mL dry three-necked flask, stir evenly and heat to 65° C., then slowly add 7.7 mL of 4-chloro-1-butene, continue to react at 65° C. for 4 h after the addition is complete, cool to room temperature after the reaction is completed, and distill under reduced pressure to obtain intermediate 2;

[0037] S3. In a 500 mL dry brown three-necked flask under nitrogen protection, add 4.2 mL of resorcinol, 4 g of anhydrous aluminum chloride and 200 mL of chloroform in sequence, stir evenly, add 8.9 g of intermediate 2, then stir and heat to 115 °C, react at 115 °C for 12 h. After the reaction is completed, slowly pour the reaction mixture into ice water, precipitate solid, filter, and recrystallize with 80% methanol aqueous solution to obtain an auxiliary agent.

[0038] Example 2, preparing a composite modified hot melt adhesive film, the specific steps are as follows:

[0039] Weigh 70 parts of ethylene-vinyl acetate copolymer, 10 parts of nitrile rubber, 5 parts of titanium dioxide, 5 parts of talc, 10 parts of ethylene-propylene copolymer, 5 parts of rosin resin, 3 parts of maleic anhydride grafted polyethylene, 1 part of vinyltrimethoxysilane, 0.5 parts of the auxiliary agent prepared in Example 1, and 0.01 parts of benzoyl peroxide by weight, and put all the raw materials into a blender and mix them evenly, then put them into a twin-screw extruder for melt blending, and extrude and pelletize; finally, the pellets are dried and added to an extrusion casting machine, cast, cooled and shaped, to obtain a composite modified hot melt adhesive film.

[0040] Example 3, preparing a composite modified hot melt adhesive film, the specific steps are as follows:

[0041] Weigh 77 parts of ethylene-vinyl acetate copolymer, 15 parts of nitrile rubber, 6 parts of titanium dioxide, 6 parts of calcium carbonate, 6 parts of magnesium hydroxide, 6 parts of ethylene-propylene copolymer, 12 parts of block copolymer of styrene and butadiene, 6 parts of hydrogenated petroleum resin, 6 parts of phenolic terpene resin, 4 parts of maleic anhydride grafted styrene-butadiene block copolymer, 4 parts of styrene-maleic anhydride copolymer, 2 parts of 3-(methacryloyloxy)propyltrimethoxysilane, 1 part of the auxiliary agent prepared in Example 1, and 0.08 parts of di-tert-butyl peroxide, and mix all the raw materials in a blender, then place them in a twin-screw extruder for melt blending, and extrude and pelletize; finally, dry the pellets and add them to an extrusion casting machine, cast them, cool and shape them, and obtain a composite modified hot melt adhesive film.

[0042] Example 4, preparing a composite modified hot melt adhesive film, the specific steps are as follows:

[0043] Weigh 80 parts of ethylene-vinyl acetate copolymer, 20 parts of nitrile rubber, 5 parts of titanium dioxide, 5 parts of fumed silica, 5 parts of magnesium hydroxide, 5 parts of aluminum hydroxide, 10 parts of ethylene-propylene copolymer, 5 parts of ethylene-octene copolymer, 5 parts of block copolymer of styrene and butadiene, 15 parts of C5 petroleum resin, 3 parts of maleic anhydride grafted polyethylene, 2 parts of maleic anhydride grafted polypropylene, 5 parts of styrene-maleic anhydride copolymer, 3 parts of methacryloxypropyl triethoxysilane, 1.5 parts of the additive prepared in Example 1, and 0.1 part of azobisisobutyronitrile, and put all the raw materials into a blender and mix them evenly, then put them into a twin-screw extruder for melt blending, and extrude and pelletize; finally, the pellets are dried and added to an extrusion casting machine, cast, cooled and shaped to obtain a composite modified hot melt adhesive film.

[0044] Comparative Example 1: preparing a hot melt adhesive film, the specific steps are as follows:

[0045] The remaining steps remain unchanged, only the auxiliary agent in Example 2 is removed to prepare a hot melt adhesive film.

[0046] Comparative Example 2: preparing a hot melt adhesive film, the specific steps are as follows:

[0047] The remaining steps remained unchanged, except that the auxiliary agent of Example 2 was replaced with 0.25 parts of antioxidant 1010 and 0.25 parts of ultraviolet absorber UV-531 to prepare a hot melt adhesive film.

[0048] Performance Testing

[0049] The hot melt adhesive films prepared in Examples 2-4 and Comparative Examples 1-2 were subjected to the following performance tests: the bonding strength was tested according to GB / T 2790-1995 (the bonding peel strength requirement between the hot melt adhesive film and metal was ≥50N / 2.5cm; the bonding peel strength requirement between the hot melt adhesive film and the fabric was ≥25N / 2.5cm); dry heat aging was performed at 105°C for 120h, and the bonding peel strength between the hot melt adhesive film and the metal and the fabric was tested according to GB / T 2790-1995; UV aging was performed at room temperature, the vertical irradiation distance was 20cm, and the bonding peel strength between the hot melt adhesive film and the metal and the fabric was tested respectively; the test results of all items are shown in the following table:

[0050]

[0051] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0052] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A composite modified hot melt adhesive film, characterized in that: The invention comprises the following raw materials in parts by weight: 70-80 parts of ethylene-vinyl acetate copolymer, 10-20 parts of nitrile rubber, 10-20 parts of inorganic filler, 10-20 parts of toughening agent, 5-15 parts of tackifying resin, 3-10 parts of compatibilizer, 1-3 parts of coupling agent, 0.5-1.5 parts of auxiliary agent, and 0.01-0.1 parts of initiator; Wherein, the auxiliary agent is prepared by the following steps: S1. Add 2-amino-4,6-dichloro-S-triazine, triethylamine and methanol to a flask under nitrogen protection, stir and heat to 60°C, add 4-bromo-2,6-di-tert-butylphenol, react for 4 hours, cool, and distill under reduced pressure to obtain intermediate 1; S2. Add intermediate 1, triethylamine and dimethyl sulfoxide to a flask under nitrogen protection, heat to 65°C with stirring, add 4-chloro-1-butene, react for 4 hours, cool, and distill under reduced pressure to obtain intermediate 2; S3. In a flask under nitrogen protection, add resorcinol, anhydrous aluminum chloride and chloroform, stir, add intermediate 2, raise the temperature to 115°C and react for 12 hours. After the reaction, pour the reaction mixture into ice water, precipitate solid, filter, and recrystallize to obtain an auxiliary agent.

2. The composite modified hot melt adhesive film according to claim 1, characterized in that: The amount ratio of 2-amino-4,6-dichloro-S-triazine, 4-bromo-2,6-di-tert-butylphenol, triethylamine and methanol in step S1 is 16.5 g:30.7 g:16.7 mL:240 mL.

3. The composite modified hot melt adhesive film according to claim 1, characterized in that: The usage ratio of the intermediate 1, 4-chloro-1-butene, triethylamine and dimethyl sulfoxide in step S2 is 25.9 g:7.7 mL:11.7 mL:200 mL.

4. The composite modified hot melt adhesive film according to claim 1, characterized in that: The usage ratio of the intermediate 2, resorcinol, anhydrous aluminum chloride and chloroform in step S3 is 8.9 g:4.2 mL:4 g:200 mL.

5. The composite modified hot melt adhesive film according to claim 1, characterized in that: The inorganic filler is one or more of titanium dioxide, talc, calcium carbonate, fumed silica, magnesium hydroxide and aluminum hydroxide.

6. The composite modified hot melt adhesive film according to claim 1, characterized in that: The toughening agent is one or more of ethylene-propylene copolymer, ethylene-octene copolymer, and block copolymer of styrene and butadiene.

7. The composite modified hot melt adhesive film according to claim 1, characterized in that: The tackifying resin is one or more of rosin resin, hydrogenated petroleum resin, phenolic terpene resin and C5 petroleum resin.

8. The composite modified hot melt adhesive film according to claim 1, characterized in that: The compatibilizer is one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted styrene-butadiene block copolymer, and styrene-maleic anhydride copolymer.

9. The composite modified hot melt adhesive film according to claim 1, characterized in that: The coupling agent is one or more of vinyl trimethoxy silane, vinyl triethoxy silane, 3-(methacryloxy)propyl trimethoxy silane, and methacryloxypropyl triethoxy silane; the initiator is one or more of benzoyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile.

10. The method for preparing a composite modified hot melt adhesive film according to claim 1, characterized in that: The following steps are involved: Weigh each raw material by weight and put all the raw materials into a mixer to mix evenly, then put them into a twin-screw extruder for melt blending, extrusion and pelletizing; finally, the pellets are dried and added to an extrusion casting machine, cast, cooled and shaped to obtain a composite modified hot melt adhesive film.

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