KR-20260065961-A - PRESSURE-SENSITIVE ADHESIVE TAPE

Abstract

The present invention aims to provide an adhesive tape having excellent flexibility and impact resistance, as well as low environmental burden. The present invention is an adhesive tape having a foamed substrate and at least one adhesive layer, wherein the foamed substrate contains a block copolymer having a block derived from a (meth)acrylic monomer, and the adhesive tape contains bio-derived carbon.

Inventors

• 우치다 노리유키
• 이시도 야스시
• 후쿠야마 마코토
• 니시가키 다츠야
• 호리오 아키후미
• 야스다 히나

Assignees

• 세키스이가가쿠 고교가부시키가이샤

Dates

Publication Date

20260511

Application Date

20211027

Priority Date

20201028

Claims (16)

1. An adhesive tape having a foam substrate and at least one adhesive layer, The above foam substrate contains a block copolymer having a block derived from a (meth)acrylic monomer, and The above adhesive tape is an adhesive tape containing bio-derived carbon.
2. In Article 1, The above block copolymer is an adhesive tape having at least one hard block.
3. In Article 2, The above block copolymer is an adhesive tape containing 1 weight% or more and 40 weight% or less of the above hard block.
4. In Article 2 or Article 3, The above hard block is an adhesive tape having a structure derived from a vinyl aromatic compound monomer.
5. In any one of paragraphs 2 through 4, The above hard block is an adhesive tape having a structure derived from a monomer having a crosslinkable functional group.
6. An adhesive tape having a foam substrate and at least one adhesive layer, The above foam substrate contains a copolymer, and The above copolymer has a structure derived from a vinyl aromatic compound monomer and a structure derived from a (meth)acrylic monomer, and The above adhesive tape is an adhesive tape containing bio-derived carbon.
7. In Article 6, The above copolymer is an adhesive tape having a structure derived from a monomer having a crosslinkable functional group.
8. In Article 6 or Article 7, An adhesive tape having a content of a structure derived from the (meth)acrylic monomer in the copolymer of 70 weight% or more and 98 weight% or less.
9. In any one of paragraphs 1 through 8, The above foam substrate is an adhesive tape containing bio-derived carbon.
10. In any one of paragraphs 1 through 9, The above (meth)acrylic monomer is an adhesive tape containing a (meth)acrylic monomer containing bio-derived carbon.
11. In Article 10, The above-mentioned (meth)acrylic monomer containing bio-derived carbon is an adhesive tape having an alkyl group having 7 to 12 carbon atoms.
12. In Article 10 or Article 11, An adhesive tape in which the above-mentioned bio-derived carbon-containing (meth)acrylic monomer is a (meth)acrylic monomer having a glass transition temperature Tg of -40°C or lower.
13. In any one of paragraphs 10 to 12, The above-mentioned bio-derived carbon-containing (meth)acrylic monomer is an adhesive tape that is n-heptylacrylate or n-octylacrylate.
14. In any one of paragraphs 1 to 13, The above adhesive tape is an adhesive tape having a bio-derived carbon content of 50 weight% or more.
15. In any one of paragraphs 1 to 14, The above foamed substrate is an adhesive tape having a bio-derived carbon content of 50 weight% or more.
16. In any one of paragraphs 1 to 15, The above block copolymer or the above copolymer is an adhesive tape having a bio-derived carbon content of 50 weight% or more.

Description

Adhesive Tape {PRESSURE-SENSITIVE ADHESIVE TAPE} The present invention relates to an adhesive tape. In portable electronic devices such as mobile phones and personal digital assistants (PDAs), adhesive tapes are used for assembly (e.g., Patent Documents 1 and 2). Additionally, adhesive tapes are also used to secure automotive electronic device components, such as automotive panels, to the vehicle body. FIG. 1 (a) is a front view showing an aspect of the adhesive tape retention test, and FIG. 1 (b) is a side view showing an aspect of the adhesive tape retention test. The embodiments of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. (Example 1) (1) Manufacturing of a non-foamed substrate 0.902 g of 1,6-hexanedithiol, 1.83 g of carbon disulfide, and 11 mL of dimethylformamide were added to a two-necked flask and stirred at 25 °C. To this, 2.49 g of triethylamine was added dropwise over 15 minutes and stirred at 25 °C for 3 hours. Subsequently, 2.75 g of methyl-α-bromophenylacetic acid was added dropwise over 15 minutes and stirred at 25 °C for 4 hours. Afterward, 100 mL of extraction solvent (n-hexane:ethyl acetate = 50:50) and 50 mL of water were added to the reaction mixture for fractional extraction. The organic layers obtained from the first and second fractional extractions were mixed and washed sequentially with 50 mL of 1 M hydrochloric acid, 50 mL of water, and 50 mL of saturated saline. Sodium sulfate was added to the organic layer after washing and dried, then the sodium sulfate was filtered, and the filtrate was concentrated using an evaporator to remove the organic solvent. The obtained concentrate was purified by silica gel column chromatography to obtain the RAFT agent. 87 parts by weight of styrene (St), 12 parts by weight of acrylic acid (AAc), 1 part by weight of hydroxyethyl acrylate (HEA), 1.9 parts by weight of RAFT, and 0.2 parts by weight of 2,2'-azobis(2-methylbutyronitrile) (ABN-E) were added to a two-necked flask, and the temperature was raised to 85 °C while purging the flask with nitrogen gas. Subsequently, the polymerization reaction was carried out by stirring at 85 °C for 6 hours (first stage reaction). After the reaction was finished, 4000 parts by weight of n-hexane were added to a flask and stirred to precipitate the reaction mixture, then the unreacted monomers (St, AA, HEA) and RAFT agent were filtered, and the reaction mixture was dried under reduced pressure at 70°C to obtain a copolymer (hard block). A mixture comprising 50 parts by weight of butyl acrylate (BA, of non-biological origin), 50 parts by weight of n-heptyl acrylate (nHPA, of biological origin), 0.058 parts by weight of ABN-E, and 50 parts by weight of ethyl acetate, and the copolymer obtained above (hard block) were placed into a two-necked flask, and the temperature was raised to 85°C while replacing the inside of the flask with nitrogen gas. Subsequently, a polymerization reaction was carried out by stirring at 85°C for 6 hours (second stage reaction), and a reaction solution containing a block copolymer formed from a hard block and a block (soft block) derived from a (meth)acrylic monomer was obtained. In addition, the amount of the mixture (block derived from a (meth)acrylic monomer and hard block) was set such that the content of the hard block in the obtained block copolymer was 17% by weight. A portion of the reaction solution was taken, 4,000 parts by weight of n-hexane were added to it, and the reaction product was precipitated by stirring. Then, unreacted monomers (BA, nHPA) and the solvent were filtered, and the reaction product was dried under reduced pressure at 70°C to obtain the block copolymer from the reaction solution. The weight-average molecular weight of the obtained block copolymer was measured by the GPC method and was 250,000. The weight-average molecular weight was measured using a Waters "2690 Separations Module" as the measuring instrument, a Showa Electric "GPC KF-806L" as the column, and ethyl acetate as the solvent, under conditions of a sample flow rate of 1 mL/min and a column temperature of 40°C. The obtained block copolymer was dissolved in ethyl acetate to a solid content of 35%, and 0.30 parts by weight of Xpancel 461-40 (manufactured by Nippon Philite, indicated as DU40 in the table) as a blowing agent and 0.2 parts by weight of Tetrad C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent were added to 100 parts by weight of the block copolymer and further stirred sufficiently to obtain a base solution. The obtained base solution was coated onto the release-treated surface of a 50 μm polyethylene terephthalate (PET) film on which a release treatment had been performed on one side, and an unfoamed base was obtained by drying at 90°C for 7 minutes. The thickness of the unfoamed base was adjusted so that it was 100 μm when the unfoamed base was heated a