Water-based pressure-sensitive adhesive compositions

Patent metadata

Field	Value
Publication number	US-2017362467-A1
Application number	US-201515533536-A
Country	US
Kind code	A1
Filing date	Dec 14, 2015
Priority date	Dec 30, 2014
Publication date	Dec 21, 2017
Grant date	—

Abstract

A pressure-sensitive adhesive is provided that is a dried product of a latex composition, which is formed from an emulsion composition. The latex composition and the emulsion composition are also provided. The emulsion composition has droplets that contain various monomers plus a (meth)acrylate polymer dissolved in the monomers. Additionally, an article containing Ca layer of the pressure-sensitive adhesive and a method of forming the pressure-sensitive adhesive are provided. The pressure-sensitive adhesives often have both high peel adhesion and high shear strength (i.e., high cohesive strength or high shear holding power).

First claim

1 . An emulsion composition comprising:
a) water; b) a polymerizable surfactant having an unsaturated group that can undergo free radical polymerization; c) a first monomer composition comprising
1) an alkyl (meth)acrylate having an alkyl group with at least six carbon atoms;
2) a first acidic monomer having a glass transition temperature equal to at least 100° C. when measured as a homopolymer; and
3) a second acidic monomer having a glass transition temperature equal to no greater than 50° C. when measured as a homopolymer; and
d) a second (meth)acrylate polymer in an amount of 0.5 to 15 weight percent based on a total weight of the first monomer composition, wherein
the second (meth)acrylate polymer has a weight average molecular weight in a range of 3,000 to 150,000 Daltons,
the second (meth)acrylate polymer has a glass transition temperature greater than −50° C., and
the second (meth)acrylate polymer is formed from a second monomer composition comprising at least 10 weight percent of a non-acidic high T g monomer based on a total weight of monomers in the second monomer composition, the non-acidic high T g monomer having a glass transition temperature equal to at least 80° C. when measured as a homopolymer;
wherein
the emulsion has a first phase comprising water and a second phase dispersed as droplets within the first phase; and
the droplets comprise a mixture comprising
i) at least 85 weight percent of the first monomer composition; and
ii) the second (meth)acrylate polymer, wherein the second (meth)acrylate polymer is not miscible with the first phase and wherein the second (meth)acrylate polymer is dissolved in the first monomer composition within the droplets.

2 . The emulsion composition of claim 1 , wherein the first monomer composition comprises:
65 to 98.5 weight percent of the alkyl (meth)acrylate having at least six carbon atoms; 0 to 20 weight percent of an alkyl (meth)acrylate having an alkyl group with one to five carbon atoms; 0.5 to 5 weight percent of the first acidic monomer; and 1 to 10 weight percent of the second acidic monomer,
wherein each amount is based on a total weight of monomers in the first monomer composition.

3 . The emulsion of claim 1 , wherein the first acidic monomer in the first monomer composition comprises acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, maleic acid, or a mixture thereof and wherein the second acidic monomer in the first monomer composition comprises carboxyethyl acrylate, mono-2-acryloyloxyethyl succinate, or a mixture thereof.

4 . The emulsion of claim 1 , wherein the second (meth)acrylate polymer is a reaction product of a second monomer composition comprising:
10 to 100 weight percent of the non-acidic high T g monomer; 0 to 90 weight percent alkyl acrylate having a linear or branched alkyl group with at least four carbon atoms and/or an alkyl methacrylate having a linear or branched alkyl group with at least five carbon atoms; 0 to 10 weight percent polar monomer that is an acid-containing monomer, a hydroxyl-containing monomer, or a mixture thereof,
wherein each amount is based on a total weight of monomers in the second monomer composition.

5 . The emulsion composition of claim 1 , wherein the non-acidic high T g monomer in the second monomer composition comprises an alkyl (meth)acrylate having a cyclic alkyl group with 6 to 12 carbon atoms.

6 . The emulsion composition of claim 1 , wherein the non-acidic high T g monomer in the second monomer composition comprises an alkyl methacrylate having a linear or branched alkyl group with 1 to 4 carbon atoms, acrylamide, (meth)acrylonitrile, N-alkyl acrylamide having an alkyl group with 1 to 10 carbon atoms, N,N-dialkyl acrylamide having alkyl groups with 1 to 10 carbon atoms, or a combination thereof.

7 . The emulsion composition of claim 1 , wherein the non-acidic high T g monomer comprises 1) a first high T g monomer comprising an alkyl (meth)acrylate having a cyclic alkyl group with 6 to 12 carbon atoms, an alkyl methacrylate having a linear or branched alkyl group with 1 to 4 carbon atoms, or a combination thereof, and 2) a second high T g monomer comprising acrylamide, (meth)acrylonitrile, N-alkyl acrylamide having an alkyl group with 1 to 10 carbon atoms, N,N-dialkyl acrylamide having alkyl groups with 1 to 10 carbon atoms, or a combination thereof.

8 . The emulsion composition of claim 1 , further comprising a C9-based hydrocarbon tackifier.

9 . A latex composition comprising a polymerized product of the emulsion composition of claim 1 , wherein the latex composition comprises polymeric latex particles.

10 . The latex composition of claim 9 further comprising a tackifier that is water dispersible.

11 . The latex composition of claim 9 , wherein in the polymeric latex particles have a single glass transition temperature as determined using a Differential Scanning calorimeter.

12 . The latex composition of claim 9 , wherein the second (meth)acrylate polymer and a polymerized product of the first monomer composition are together in the same polymeric particles.

13 . A pressure-sensitive adhesive comprising a dried product of the latex composition of claim 9 .

14 . An article comprising:
a) a substrate; and b) a first pressure-sensitive adhesive layer positioned adjacent to a first major surface of the substrate, wherein the first pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive of claim 13 .

15 . A method of forming a pressure-sensitive adhesive, the method comprising:
a) forming an emulsion composition according to claim 1 , b) polymerizing the emulsion composition to form a latex composition comprising polymeric latex particles; and c) drying the latex composition to form the pressure-sensitive adhesive.

Assignees

• 3M Innovative Properties Co

Inventors

• Qie Lili
• Jacobsen John R
• Sakizadeh Kumars
• Song Zhipeng
• Seth Jayshree
• Tseng Chi-Ming

Classifications

• C08F220/06

  Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof · CPC title

• C09J4/06 Primary

  {Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond} in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00 · CPC title

• C08F2500/02

  Low molecular weight, e.g. <100,000 Da. · CPC title

• G01N25/4866

  by using a differential method · CPC title

• C09J133/06

  of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical · CPC title