Film-initiated cure of structural adhesive film

Patent metadata

Field	Value
Publication number	US-2025250467-A1
Application number	US-202519010860-A
Country	US
Kind code	A1
Filing date	Jan 6, 2025
Priority date	Feb 9, 2018
Publication date	Aug 7, 2025
Grant date	—

Abstract

Curable adhesive free-standing films and adhesive systems comprising such films are provided. In some embodiments, a curable adhesive free-standing film comprises a blend of: a) a first film-forming polymer or oligomer; b) a first species comprising first unsaturated free-radically polymerizable groups, which may be a) or a species other than a); c) a first transition metal cation; d) a reducing agent; and no oxidizing agent. In some embodiments, an adhesive system comprises: I) a first curable adhesive free-standing film as described preceding; and II) a second curable adhesive free-standing film comprising a blend of: e) a second film-forming polymer or oligomer; f) a second species comprising second unsaturated free-radically polymerizable groups, which may be e) or may be a species other than e); and g) an oxidizing agent. In some embodiments, the curable adhesive free-standing films may be pressure sensitive adhesives prior to cure. Methods of use are provided.

First claim

We claim:

1 . A curable adhesive free-standing film comprising a blend of:
a) a first film-forming polymer or oligomer; b) a first species comprising first unsaturated free-radically polymerizable groups, which may be a) or a species other than a); c) a first transition metal cation; and d) a reducing agent which is not a), b), or c);
wherein the curable adhesive free-standing film comprises no oxidizing agent which is not a), b), c), or d).

2 . The curable adhesive free-standing film according to claim 1 , wherein b) is a).

3 . The curable adhesive free-standing film according to any of claim 1 , wherein b) is a species other than a), wherein a) does not comprise unsaturated free-radically polymerizable groups.

4 . The curable adhesive free-standing film according to claim 3 , wherein a) is selected from the group consisting of acrylic polymers, rubber polymers, polyester polymers, polyurethane polymers, polyamide polymers, and combinations thereof.

5 . The curable adhesive free-standing film according to claim 1 , wherein the reducing agent does not comprise a transition metal, nitrogen or sulfur.

6 . The curable adhesive free-standing film according to claim 1 , wherein the reducing agent is selected from organic reducing agents.

7 . The curable adhesive free-standing film according to claim 1 , which is a pressure sensitive adhesive.

8 . An adhesive system comprising:
I) a first curable adhesive free-standing film which is the curable adhesive free-standing film according to claim 1 ; and II) a second curable adhesive free-standing film comprising a blend of:
e) a second film-forming polymer or oligomer;
f) a second species comprising second unsaturated free-radically polymerizable groups, which may be e) or may be a species other than e); and
g) an oxidizing agent which is not e) or f).

9 . The adhesive system according to claim 8 , wherein f) is e).

10 . The adhesive system according to claim 8 , wherein f) is a species other than e), wherein e) does not comprise unsaturated free-radically polymerizable groups.

11 . The adhesive system according to claim 10 , wherein e) is selected from the group consisting of acrylic polymers, rubber polymers, polyester polymers, polyurethane polymers, polyamide polymers, and combinations thereof.

12 . The adhesive system according to claim 8 , wherein the second curable adhesive free-standing film is a pressure sensitive adhesive.

13 . A method of binding two substrates comprising the steps of:
1) providing a first substrate bearing on a first surface the first curable adhesive free-standing film according to claim 8 ; 2) providing a second substrate bearing on a second surface the second curable free-standing adhesive film according to claim 8 ; and 3) bringing together the first and second surfaces of the first and second substrates such that the first and second curable adhesive films are in contact.

14 . The method of claim 13 , comprising:
1) providing the second curable adhesive free-standing film according to claim 8 ; 2) providing a first substrate bearing on a first surface a first portion of the first curable adhesive free-standing film according to claim 8 ; 3) providing a second substrate bearing on a second surface a second portion of the first curable free-standing adhesive film according to claim 8 ;
where the first and second portions have compositions chosen independently of each other; and
4) bringing together 1), 2), and 3) such that the first portion of the first curable adhesive free-standing film and the second portion of the first curable adhesive free-standing film are in contact with opposite faces of the second curable adhesive free-standing film.

15 . The method of claim 13 , comprising:
1) providing the first curable adhesive free-standing film according to claim 8 ; 2) providing a first substrate bearing on a first surface a first portion of the second curable adhesive free-standing film according to claim 8 ; 3) providing a second substrate bearing on a second surface a second portion of the second curable free-standing adhesive film according to claim 8 ;
wherein the first and second portions have compositions chosen independently of each other; and
4) bringing together 1), 2), and 3) such that the first portion of the second curable adhesive free-standing film and the second portion of the second curable adhesive free-standing film are in contact with opposite faces of the first curable adhesive free-standing film.

Assignees

• 3M Innovative Properties Company

Inventors

• Ranade Shantanu R
• Kugel Alexander J
• Claussen Kai U
• Khurana Rachna
• Moren Dean M
• Sikorski Jr William H
• Townsend Erik M

Classifications

• C09J2433/00

  Presence of (meth)acrylic polymer · CPC title

• C09J11/04

  inorganic · CPC title

• C09J5/04 Primary

  involving separate application of adhesive ingredients to the different surfaces to be joined · CPC title

• C09J2301/302

  the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C · CPC title

• C09J2301/208

  the adhesive layer being constituted by at least two or more adjacent or superposed adhesive layers, e.g. multilayer adhesive · CPC title