Hot melt pressure sensitive adhesives based on ethylene-acrylate block copolymers

Patent metadata

Field	Value
Publication number	US-2023002651-A1
Application number	US-202017782181-A
Country	US
Kind code	A1
Filing date	Dec 4, 2020
Priority date	Dec 6, 2019
Publication date	Jan 5, 2023
Grant date	—

Abstract

A hot melt pressure sensitive adhesive composition comprises: (a) a block copolymer comprising a first polymer block comprising an ethylene residue and a second polymer block comprising a C1 to C4 alkyl acrylate residue, wherein the block copolymer has a melt index as measured in accordance with ASTM D1238 of between about 0.1 and about 250 g/10 min; (b) a tackifying resin; and (c) a plasticizer. A method for making a laminate comprises the steps of: applying the hot melt pressure sensitive adhesive composition of the invention in a molten state to a primary substrate and allowing the adhesive to cool to form a bond with said primary substrate. Certain adhesives the invention perform comparably to certain styrene block copolymer adhesives, but provides an alternative polymer source.

First claim

1 . A hot melt pressure sensitive adhesive composition comprising:
(a) a block copolymer comprising a first polymer block comprising an ethylene residue and a second polymer block comprising a C 1 to C 4 alkyl acrylate residue, wherein the block copolymer has a melt index as measured in accordance with ASTM D1238 of between about 0.1 and about 250 g/10 min; (b) a tackifying resin; and (c) a plasticizer.

2 . The composition of claim 1 , wherein the block copolymer has a structure of formula (I):
[P1 a -P2 b ] n   (I)
wherein P1 is the first polymer block, P2 is the second polymer block, a indicates the number of the first polymer blocks within the structural unit [P1 a -P2 b ] and is from 1 to 5, b indicates the number of the second polymer blocks within the structural unit [P1 a -P2 b ] and is from 1 to 5, and n indicates the number of the structural units within the block copolymer and is from 1 to 5.

3 . The composition of claim 1 , wherein the C 1 to C 4 alkyl acrylate is selected from the group consisting of methyl acrylate and butyl acrylate.

4 . The composition of claim 1 , wherein the block copolymer comprises a first block copolymer wherein the C 1 to C 4 alkyl acrylate is methyl acrylate and a second block copolymer wherein the C 1 to C 4 alkyl acrylate is butyl acrylate.

5 . The composition of claim 2 , wherein the C 1 to C 4 alkyl acrylate comprises methyl acrylate and the block copolymer comprises methyl acrylate residue in an amount of between about 7.5 and about 35 wt %.

6 . The composition of claim 2 , wherein the C 1 to C 4 alkyl acrylate comprises butyl acrylate and the block copolymer comprises butyl acrylate residue in an amount of between about 15 and about 40 wt %.

7 . The composition of claim 1 , wherein the crossover temperature of the composition is at least 45° C.

8 . The composition of claim 1 , wherein:
the block copolymer is present in an amount of between about 15% and about 40%, by weight; the tackifying resin is present in an amount of between about 30% and about 75%, by weight; and the plasticizer is present in an amount of between about 5% and about 40%, by weight.

9 . The composition of claim 1 , wherein the plasticizer and the tackifier have a polarity adapted to selectively be miscible with the first polymer block.

10 . The composition of claim 1 , wherein:
the plasticizer is selected from the group consisting of an isobutylene/butene copolymer and a mineral oil comprising non-polar aliphatic and alicyclic hydrocarbons; and the tackifier is selected from the group consisting of a hydrogenated C 5 aliphatic resin and an unhydrogenated C 5 aliphatic resin.

11 . The composition of claim 1 , wherein the plasticizer and the tackifier have a polarity adapted to selectively be miscible with the second polymer block.

12 . The composition of claim 1 , wherein:
the plasticizer comprises a benzoate ester; and the tackifier comprises a rosin ester.

13 . The composition of claim 1 , wherein the viscosity of the composition is between about 1,000 cP and about 250,000 cP at 163° C.

14 . The composition of claim 1 having a Ring & Ball softening point of between about 50° C. and about 150° C.

15 . (canceled)

16 . (canceled)

17 . (canceled)

18 . A method of making a laminate comprising the step of applying the hot melt pressure sensitive adhesive composition of claim 1 in a molten state to a primary substrate and allowing the adhesive to cool to form a bond with said primary substrate.

19 . The method of claim 18 , wherein the laminate is a tape or label.

20 . The method of claim 18 further comprising mating a secondary substrate to the primary substrate by contacting the secondary substrate with the adhesive composition while the adhesive is in a molten state.

21 . The method of claim 18 , wherein the primary substrate is a polyethylene film.

22 . The method of claim 20 , wherein the secondary substrate is a non-woven layer.

23 . A laminate made by the method of claim 18 .

Assignees

• Bostik Inc

Inventors

• Davis Kathleen M
• Vitrano Michael D
• Czaplewski Patrick J
• Rohde Lauren M

Classifications

• C08F220/06

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

• C09J153/00 Primary

  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 · CPC title

• C08F210/02

  Ethene · CPC title

• C09J5/06

  involving heating of the applied adhesive · CPC title