A heat-expandable peelable pressure-sensitive adhesive tape

Abstract

The invention discloses a heat-expandable peelable pressure-sensitive adhesive tape, belonging to the technical field of pressure-sensitive adhesive tape. 90-100 parts of resin, 10-20 parts of monomer, 15-25 parts of expanded microspheres, 8-15 parts of flame retardant, 2-4 parts of photoinitiator, and 110-130 parts of solvent are fully stirred by weight, applied on a plastic film by a coating machine, dried at 60-90°C, and then UV-cured under a 300-500nm UV furnace, rolled up, and a heat-expandable peelable pressure-sensitive adhesive tape is obtained. The flame retardant of the present invention is rich in halogen-free flame retardant elements nitrogen, phosphorus, and silicon, and the flame retardant and the monomer can produce a chemical reaction under the action of a photoinitiator and cross-link, and then the flame retardant can be stably present in the pressure-sensitive adhesive, give full play to the effect, and then the pressure-sensitive adhesive tape of the present invention has high efficiency, safety and long-term flame retardant effect. At the same time, the synergistic effect between the flame retardant and the remaining raw materials makes the pressure-sensitive adhesive tape of the present invention have good bonding effect and no residual glue is left after peeling.

Description

Technical Field

[0001] The invention belongs to the technical field of pressure-sensitive adhesive tapes, and in particular relates to a heat-expandable peelable pressure-sensitive adhesive tape. Background Art

[0002] The electronics industry is developing rapidly, and various tapes are used in computers, mobile phones and other electronic products for temporary or permanent fixation of internal components to replace the original mechanical fixation or welding fixation. The application of heat-expandable peelable pressure-sensitive tape mainly includes lithium battery manufacturing, medical products, packaging products, sanitary products and other fields.

[0003] In special application areas, pressure-sensitive tapes are usually required to have flame retardant and fireproof properties. At present, most domestic flame-retardant pressure-sensitive tapes are halogen-based flame retardants. Although halogen-based flame retardants have good effects and can be used in many occasions, the decomposition and combustion of halogen-based flame-retardant pressure-sensitive adhesives will produce a lot of smoke and toxic and corrosive hydrogen halide gas, which will hinder firefighting and personnel evacuation, corrode instruments and equipment, and cause "secondary disasters". In addition, the combustion products (halides) have a long atmospheric life. Once they enter the atmosphere, it is difficult to get out, which seriously pollutes the environment. Therefore, it is urgent to design a peelable pressure-sensitive tape with efficient and safe flame retardant effect. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a heat-expandable peelable pressure-sensitive adhesive tape.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A heat-expandable peelable pressure-sensitive adhesive tape comprises the following preparation steps:

[0007] 90-100 parts of resin, 10-20 parts of monomer, 15-25 parts of expanded microspheres, 8-15 parts of flame retardant, 2-4 parts of photoinitiator and 110-130 parts of solvent are fully stirred to mix evenly, then coated on a plastic film by a coater, dried at 60-90°C, and then UV-cured in a 300-500nm UV oven, and finally rolled up to obtain a heat-expandable peelable pressure-sensitive adhesive tape.

[0008] Furthermore, the resin is one or more of polyepoxy acrylate resin, polyurethane modified acrylic resin, and polysilicone modified acrylic resin.

[0009] Furthermore, the monomer is one or more of n-butyl acrylate, lauryl acrylate, styrene, vinyl acetate, N-vinyl pyrrolidone, and isobornyl acrylate.

[0010] Furthermore, the flame retardant is prepared by the following steps:

[0011] S1. Under nitrogen protection, add melamine, diethylphosphoacetic acid and DMSO (dimethyl sulfoxide) into a dry brown three-necked flask, stir to dissolve, then add EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and NHS (N-hydroxysuccinimide), stir evenly and heat to 50°C, keep warm for 6 hours, cool to room temperature after the reaction, and then distill under reduced pressure to obtain intermediate 1; the dosage ratio of melamine, diethylphosphoacetic acid, EDC, NHS and DMSO is 11.4g:30.1mL:1.03g:0.62g:120mL;

[0012] The molar ratio of melamine to diethylphosphoacetic acid is controlled to be 1:2.05-2.1, and the -COOH of diethylphosphoacetic acid and the -NH2 of melamine undergo amidation reaction under the action of EDC and NHS. The reaction equation is as follows:

[0013] ,

[0014] S2. Under nitrogen protection, add 1,6-hexanediol diacrylate, DBU (1,8-diazobisspiro[5.4.0]undec-7-ene) and DMF (N,N-dimethylformamide) into a dry brown three-necked flask, stir evenly, and then slowly add the mixed solution of intermediate 1 and DMF. After the addition is completed, heat to 60°C and react for 48 hours. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain intermediate 2. The usage ratio of intermediate 1, 1,6-hexanediol diacrylate, DBU and DMF is 41g:20.7mL:0.7mL:200mL.

[0015] Under the catalytic action of DBU, the molar ratio of intermediate 1 to 1,6-hexanediol diacrylate is controlled to be 1:1.05-1.1, and intermediate 1 and 1,6-hexanediol diacrylate undergo Michael addition reaction. The reaction process is as follows:

[0016] ,

[0017] S3. Under nitrogen protection, add 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane, intermediate 2 and DMF to a dry brown three-necked flask, stir to dissolve, and then slowly add triethylamine. After the addition is completed, heat to 80°C and stir to react for 3 hours. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain a flame retardant. The dosage ratio of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane, intermediate 2, triethylamine and DMF is 6.6mL:45.1g:10mL:220mL.

[0018] Triethylamine is used as an acid binding agent, and the molar ratio of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane to intermediate 2 is controlled to be 1:2.1-2.2. -NH- of intermediate 2 and -Cl of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane undergo substitution reaction. The reaction process is shown below:

[0019] ,

[0020] The organic phosphorus in the flame retardant of the present invention decomposes to generate phosphorus oxygen-containing acid, which can promote the formation of a carbon layer on the substrate. A large amount of carbon layer plays a role in blocking the flow of combustible gas and heat, thereby achieving a flame retardant effect; under the action of nitrogen element, the carbon layer formed on the surface of the substrate will expand and foam to form a porous foam structure, and the expanded porous foam carbon layer will further block the process of heat and oxygen exchange between the substrate and the outside world, further improving the flame retardant effect. At the same time, the flame retardant releases a large amount of non-combustible gas such as H2O, NH3, CO2, NO2, etc. during the combustion process, which can dilute the concentration of combustible gas and delay the spread of flame; silicon element generates an inorganic heat-insulating and insulating protective layer containing -Si-O bonds and -Si-C- bonds during combustion, which not only prevents the decomposition products generated by combustion from escaping, but also inhibits the thermal decomposition of the substrate, achieving the purposes of high flame retardancy, low smoke emission and low harmfulness.

[0021] In addition, the flame retardant of the present invention contains multiple acrylate groups, which can produce chemical reactions with monomers under the influence of photoinitiators. On the one hand, various polar groups are introduced into the pressure-sensitive adhesive, thereby increasing the secondary forces between molecules, and thus the pressure-sensitive adhesive of the present invention has relatively large bonding strength and cohesive strength. On the other hand, the flame retardant of the present invention can stably exist in the pressure-sensitive adhesive and is not easy to migrate or come out, thereby being able to exert efficient, safe, long-lasting and stable flame-retardant and smoke-suppressing effects.

[0022] Furthermore, the photoinitiator is one or more of 2,4,6 (trimethylbenzoyl) diphenylphosphine oxide, benzoin dimethyl ether, methyl o-benzoylbenzoate, 4-chlorobenzophenone, and 4-phenylbenzophenone.

[0023] Furthermore, the solvent is one or more of toluene, cyclohexanone, ethanol, ethyl acetate, dimethyl carbonate, methyl butyl ketone, and ethylene glycol monoethyl ether.

[0024] The raw material components in the pressure-sensitive adhesive of the present invention are reasonably combined, and active functional groups such as amino groups, ester groups, and amide groups are introduced, so that the components of the pressure-sensitive adhesive can form good physical crosslinks, thereby improving the storage modulus of the pressure-sensitive adhesive at high temperatures, reducing the loss modulus, and significantly improving the heat resistance and aging resistance of the pressure-sensitive adhesive, and no residual adhesive will be left after peeling.

[0025] Furthermore, the plastic film is one of polyethylene terephthalate film, polypropylene film, polybutylene terephthalate film, polyvinyl chloride film, and polyethylene-vinyl acetate film.

[0026] Beneficial effects of the present invention: The flame retardant of the present invention is rich in halogen-free flame retardant elements such as nitrogen, phosphorus and silicon, and the flame retardant and the monomer can undergo chemical reaction and cross-linking under the action of a photoinitiator, so that the flame retardant can stably exist in the pressure-sensitive adhesive and fully exert its effect, thereby making the pressure-sensitive adhesive tape of the present invention have high efficiency, safety and long-term flame retardant effect. At the same time, the synergistic effect between the flame retardant and the other raw materials makes the pressure-sensitive adhesive tape of the present invention have good bonding effect and no residual adhesive is left after peeling. DETAILED DESCRIPTION

[0027] 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.

[0028] Example 1

[0029] The flame retardant is prepared in the following specific steps:

[0030] S1. Under nitrogen protection, 11.4 g of melamine, 30.1 mL of diethylphosphoacetic acid and 120 mL of DMSO were added to a 250 mL dry brown three-necked flask, and 1.03 g of EDC and 0.62 g of NHS were added after stirring to dissolve. After stirring evenly, the temperature was raised to 50°C and the reaction was kept at this temperature for 6 h. After the reaction was completed, the mixture was cooled to room temperature and then distilled under reduced pressure to obtain intermediate 1.

[0031] S2, under nitrogen protection, add 20.7 mL 1,6-hexanediol diacrylate, 0.7 mL DBU and 100 mL DMF into a 500 mL dry brown three-necked flask, stir evenly, then slowly add 41 g of a mixed solution of intermediate 1 and 100 mL DMF, after adding, heat to 60 ° C and react for 48 hours, cool to room temperature after the reaction, and distill under reduced pressure to obtain intermediate 2;

[0032] S3. Under nitrogen protection, add 6.6 mL of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane, 45.1 g of intermediate 2 and 220 mL of DMF into a 500 mL dry brown three-necked flask, stir to dissolve, and then slowly add 10 mL of triethylamine. After the addition is complete, heat to 80°C and stir to react for 3 hours. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain a flame retardant.

[0033] Example 2

[0034] The preparation of heat-expandable peelable pressure-sensitive tape is carried out in the following steps:

[0035] 90 parts of polyepoxy acrylate resin, 10 parts of n-butyl acrylate, 15 parts of Matsumoto F-50 expanded microspheres, 8 parts of the flame retardant prepared in Example 1, 2 parts of 2,4,6 (trimethylbenzoyl) diphenylphosphine oxide, 70 parts of toluene, and 40 parts of ethylene glycol monoethyl ether were fully stirred by weight to mix evenly, then coated on a polyethylene terephthalate film by a coating machine, dried at 60° C., and then UV-cured in a 300-500nm UV oven, and finally rolled up to obtain a heat-expandable peelable pressure-sensitive tape.

[0036] Example 3

[0037] The preparation of heat-expandable peelable pressure-sensitive tape is carried out in the following steps:

[0038] 97 parts of polysilicone modified acrylic resin, 18 parts of lauryl acrylate, 22 parts of Matsumoto F-190D expanded microspheres, 13 parts of the flame retardant prepared in Example 1, 3 parts of benzoin dimethyl ether, methyl o-benzoylbenzoate, 60 parts of ethyl acetate, and 60 parts of methyl butyl ketone were fully stirred by weight to mix evenly, then coated on a polypropylene film by a coating machine, dried at 80° C., and then UV-cured in a 300-500 nm UV oven, and finally rolled up to obtain a heat-expandable peelable pressure-sensitive tape.

[0039] Example 4

[0040] The preparation of heat-expandable peelable pressure-sensitive tape is carried out in the following steps:

[0041] 100 parts of polyurethane modified acrylic resin, 10 parts of styrene, 10 parts of isobornyl acrylate, 25 parts of Matsumoto F-82 expanded microspheres, 15 parts of the flame retardant prepared in Example 1, 4 parts of methyl o-benzoylbenzoate, 30 parts of cyclohexanone, 70 parts of ethyl acetate, and 30 parts of dimethyl carbonate were fully stirred by weight to mix evenly, then coated on a polyvinyl chloride film by a coater, dried at 60-90° C., and then UV-cured in a 300-500nm UV oven, and finally rolled up to obtain a heat-expandable peelable pressure-sensitive tape.

[0042] Comparative Example 1

[0043] The preparation of heat-expandable peelable pressure-sensitive tape is carried out in the following steps:

[0044] The remaining steps remain unchanged, and the flame retardant of Example 2 is removed to prepare a heat-expandable peelable pressure-sensitive adhesive tape.

[0045] Comparative Example 1

[0046] The preparation of heat-expandable peelable pressure-sensitive tape is carried out in the following steps:

[0047] The remaining steps remain unchanged, and the flame retardant in Example 2 is replaced by the flame retardant Doher-6000A produced by Dongguan Doher New Material Technology Co., Ltd. to prepare a heat-expandable peelable pressure-sensitive adhesive tape.

[0048] Performance Testing

[0049] Flame retardant properties are generally expressed by the oxygen index, which refers to the minimum oxygen concentration (expressed as a percentage) required to maintain continuous burning of a wax-like substance when a material (test piece) of a certain size is placed in a test device, a mixed gas of oxygen and nitrogen is introduced under specified conditions, the test piece is ignited with an igniter, and the test piece is measured.

[0050] According to GB / T 5454-1997 standard, the minimum oxygen concentration in the oxygen / nitrogen mixed system required for the stable combustion of the heat-expandable peelable pressure-sensitive adhesive tapes of Examples 2-4 and Comparative Examples 1-2 was measured using an oxygen index meter.

[0051] The pressure-sensitive adhesive residue of the heat-expandable removable pressure-sensitive adhesive tapes prepared in Examples 2-4 and Comparative Examples 1-2 was evaluated after aging for 30 days in an environment of 100° C. and 90% humidity.

[0052] The test results are shown in Table 1 below:

[0053] ;

[0054] 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.

[0055] 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 heat-expandable peelable pressure-sensitive adhesive tape, characterized in that: The method comprises the following preparation steps: 90-100 parts of resin, 10-20 parts of monomer, 15-25 parts of expanded microspheres, 8-15 parts of flame retardant, 2-4 parts of photoinitiator and 110-130 parts of solvent are mixed by weight, coated on a plastic film by a coating machine, dried at 60-90° C., cured by ultraviolet in a 300-500nm ultraviolet oven, and rolled up to obtain a heat-expandable peelable pressure-sensitive adhesive tape; Wherein, the flame retardant is prepared by the following steps: S1. Add melamine, diethylphosphoacetic acid and DMSO into a flask under nitrogen protection, add EDC and NHS after stirring, react at 50°C for 6h, cool, and then distill under reduced pressure to obtain intermediate 1; the dosage ratio of melamine, diethylphosphoacetic acid, EDC, NHS and DMSO is 11.4g:30.1mL:1.03g:0.62g:120mL; S2. Add 1,6-hexanediol diacrylate, DBU and DMF into a flask under nitrogen protection, stir, add intermediate 1 and DMF, react at 60°C for 48h, cool, and distill under reduced pressure to obtain intermediate 2; the usage ratio of intermediate 1, 1,6-hexanediol diacrylate, DBU and DMF is 41g:20.7mL:0.7mL:200mL; S3. Under nitrogen protection, add 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane, intermediate 2 and DMF into a flask, stir and add triethylamine, react at 80°C for 3h, cool, and distill under reduced pressure to obtain a flame retardant; the amount ratio of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane, intermediate 2, triethylamine and DMF is 6.6mL:45.1g:10mL:220mL; The resin is one or more of polyepoxy acrylate resin, polyurethane modified acrylic resin, and polysilicone modified acrylic resin.

2. The heat-expandable peelable pressure-sensitive adhesive tape according to claim 1, characterized in that: The monomer is one or more of n-butyl acrylate, lauryl acrylate, styrene, vinyl acetate, N-vinyl pyrrolidone and isobornyl acrylate.

3. The heat-expandable peelable pressure-sensitive adhesive tape according to claim 1, characterized in that: The photoinitiator is one or more of 2,4,6 (trimethylbenzoyl) diphenylphosphine oxide, benzoin dimethyl ether, methyl o-benzoylbenzoate, 4-chlorobenzophenone, and 4-phenylbenzophenone.

4. The heat-expandable peelable pressure-sensitive adhesive tape according to claim 1, characterized in that: The solvent is one or more of toluene, cyclohexanone, ethanol, ethyl acetate, dimethyl carbonate, methyl butyl ketone, and ethylene glycol monoethyl ether.

5. The heat-expandable peelable pressure-sensitive adhesive tape according to claim 1, characterized in that: The plastic film is one of polyethylene terephthalate film, polypropylene film, polybutylene terephthalate film, polyvinyl chloride film and polyethylene-vinyl acetate film.