# US 10,370,528 B2 · Acrylic block copolymer and adhesive composition > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,528 B2 - Document ID: US10370528B2 - Status: Granted - Kind: B2 - Application number: 15/546,198 - Filed: 2016-01-21 - Published: 2018-01-18 - Granted: 2019-08-06 - Earliest claimed: 2015-01-27 - Assignees: Kuraray Co., Ltd. - Applicants: Kuraray Co., Ltd. - Inventors: Kanayo Nakada; Yoshihiro Morishita - Web page: https://patentgrep.com/patent/US10370528B2 ## CPC - C08L 53/00: Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers - C08F 297/026: {polymerising acrylic acid, methacrylic acid or derivatives thereof} - C08L 33/08: Homopolymers or copolymers of acrylic acid esters - C08L 33/10: Homopolymers or copolymers of methacrylic acid esters - C09J 133/08: Homopolymers or copolymers of acrylic acid esters - C09J 133/10: Homopolymers or copolymers of methacrylic acid esters - C09J 153/00: Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers - C08G 2170/20: Compositions for hot melt adhesives - C08G 2261/126: block - C08L 2205/025: containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H) - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract [Object] To provide an acrylic block copolymer which can be used in an adhesive composition to give an excellent adhesive force, cohesive force, holding power, tack, and hot-melt coatability; and also to provide an adhesive composition containing such a block copolymer. [Solution] An acrylic block copolymer (I) contains at least two polymer blocks (A) containing methacrylic acid ester units and at least one polymer block (B) containing acrylic acid ester units, wherein the acrylic block copolymer (I) has structure of blocks (A)-(B)-(A), a weight average molecular weight (Mw) ranging from 30,000 to 100,000 and a melt viscosity of not more than 100,000 mPa·s, the melt viscosity being measured at 100° C. with a Brookfield viscometer. ## Claims ### Claim 1 An acrylic block copolymer (I), comprising: a polymer block (A) comprising methacrylic acid ester units and a polymer block (B) comprising acrylic acid ester units, wherein the acrylic block copolymer (I) comprises a structure of blocks (A)-(B)-(A), a weight average molecular weight Mw of from 30,000 to 100,000, and a melt viscosity measured at 100° C. with a Brookfield viscometer of not more than 100,000 mPa·s. ### Claim 2 (depends on 1) The acrylic block copolymer (I) according to claim 1, wherein a total content of the polymer block (A) is not more than 15 mass %, and the acrylic block copolymer (I) has a molecular weight distribution Mw/Mn of 1.0 to 1.5. ### Claim 3 (depends on 1) The acrylic block copolymer (I) according to claim 1, wherein the acrylic acid ester units of the polymer block (B) is obtained from an acrylic acid ester represented by CH2═CH—COOR1, where R1represents an organic group having 1 to 10 carbon atoms. ### Claim 4 (depends on 1) The acrylic block copolymer (I) according to claim 1, which is a triblock copolymer. ### Claim 5 (depends on 1) The acrylic block copolymer (I) according to claim 1, which comprises, as the polymer block (A), a polymer block (A1) and polymer block (A2) having different weight average molecular weights. ### Claim 6 (depends on 5) The acrylic block copolymer (I) according to claim 5, wherein at least one of the polymer blocks (A1) and (A2) has a weight average molecular weight of not less than 300 and below 3,000. ### Claim 7 (depends on 1) An adhesive composition, comprising: (i) acrylic block copolymer (I) according to claim 1; and (ii) an acrylic block copolymer (II) comprising at least one polymer block (C) comprising methacrylic acid ester units and at least one polymer block (D) comprising acrylic acid ester units, wherein the acrylic block copolymer (II) has a weight average molecular weight Mw of from 50,000 to 300,000 and has a melt viscosity measured at 100° C. with a Brookfield viscometer of greater than 100,000 mPa·s. ### Claim 8 (depends on 7) The adhesive composition according to claim 7, wherein a content of the acrylic block copolymer (II) is from 1 to 500 parts by mass relative to 100 parts by mass of the acrylic block copolymer (I). ### Claim 9 (depends on 7) The adhesive composition according to claim 7, wherein the acrylic acid ester of the polymer block (D) of the acrylic block copolymer (II) is the same as the acrylic acid ester of the polymer block (B) of the acrylic block copolymer (I). ### Claim 10 (depends on 7) The adhesive composition according to claim 7, further comprising a tackifying resin. ### Claim 11 (depends on 7) A hot-melt adhesive, comprising the adhesive composition according to claim 7. ### Claim 12 (depends on 7) An adhesive product, comprising an adhesive layer formed the adhesive composition according to claim 7. ### Claim 13 (depends on 1) The acrylic block copolymer (I) of claim 1, wherein the polymer block (A) consists of the methacrylic acid ester units and the polymer block (B) consists of the acrylic acid ester units. ### Claim 14 An acrylic block copolymer (I), comprising: a polymer block (A) comprising methacrylic acid ester units and a polymer block (B) comprising acrylic acid ester units, wherein the acrylic block copolymer (I) comprises at least one structure of blocks (A)-(B)-(A), a weight average molecular weight Mw of from 30,000 to 100,000, and a melt viscosity measured at 100° C. with a Brookfield viscometer of not more than 100,000 mPa·s. ### Claim 15 (depends on 14) The acrylic block copolymer (I) according to claim 14, wherein the acrylic block copolymer (I) consists of the at least one structure blocks (A)-(B)-(A). ### Claim 16 (depends on 5) The acrylic block copolymer (I) according to claim 5, wherein at least one of the polymer blocks (A1) and (A2) has a weight average molecular weight of not less than 300 and less than 2,000. ### Claim 17 (depends on 1) The acrylic block copolymer (I) according to claim 1, wherein the acrylic block copolymer (I) consists of the structure blocks (A)-(B)-(A).