Reactive film adhesives with enhanced adhesion to metallic surfaces

• US 9,944,834 B2
• Filed: 12/15/2015
• Issued: 04/17/2018
• Est. Priority Date: 12/15/2014
• Status: Active Grant

• Current Assignee: HB Fuller Company
• Original Assignee: HB Fuller Company
• Inventors: Carlson, Brian W., Paul, Rituparna, Muvundamina, Mutombo J., Mai, Felix D.
• Primary Examiner(s): Chang, Victor S
• Application Number:
  US14/969,900
• Publication Number:
  US 20160168423A1
• Time in Patent Office: 854 Days
• CPC Class Codes: B32B 15/095 comprising polyurethanes
• CPC Class Codes: B32B 15/14 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 15/18 comprising iron or steel B32B15/011, B32B15/012 and B32B15/013 take precedence
• CPC Class Codes: B32B 2037/1253 curable adhesive
• CPC Class Codes: B32B 2037/1269 multi-component adhesive
• CPC Class Codes: B32B 2262/0261 Polyamide fibres
• CPC Class Codes: B32B 2307/50 having particular mechanical properties
• CPC Class Codes: B32B 2375/00 Polyureas; Polyurethanes
• CPC Class Codes: B32B 2405/00 Adhesive articles, e.g. adhesive tapes labels B32B2519/00
• CPC Class Codes: B32B 2457/00 Electrical equipment
• CPC Class Codes: B32B 2471/02 Carpets
• CPC Class Codes: B32B 2605/00 Vehicles
• CPC Class Codes: B32B 27/28 comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: B32B 37/1207 Heat-activated adhesive B32B37/04 takes precedence
• CPC Class Codes: B32B 37/16 with all layers existing as coherent layers before laminating
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: C09J 175/00 Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 175/04 Polyurethanes
• CPC Class Codes: C09J 2475/00 Presence of polyurethane
• CPC Class Codes: C09J 2475/003 : in the primer coating
• CPC Class Codes: C09J 5/04 : involving separate application of adhesive ingredients to the different surfaces to be joined
• CPC Class Codes: C09J 5/06 : involving heating of the applied adhesive
• CPC Class Codes: C09J 7/10 : without carriers

Abstract

Disclosed is a self-supporting, heat curable adhesive film including a surface-deactivated solid isocyanate and a blend of two different polyurethanes. A method of making an article that includes the adhesive film and article made thereby are also disclosed.

Claims

1. A self-supporting, heat curable adhesive film, comprising:

a surface-deactivated solid isocyanate,

a first polyurethane having functional groups reactive with isocyanate, and

a second polyurethane different from the first polyurethane, the second polyurethane being a carboxylic acid functional polyurethane having an acid number of from 10 to 30, and a unimodal weight average molecular weight (Mw) of no greater than about 50,000 g/mole,

wherein the adhesive film exhibits a 180 degree peel strength that is at least 30% greater than the 180 degree peel strength of Control I, when tested according to the Cured 180 Degree Peel Strength Test Method.

2. The self-supporting, heat curable adhesive film of claim 1, wherein the adhesive film has a thickness of from about 10 microns to about 200 microns.

3. The self-supporting, heat curable adhesive film of claim 1, wherein the adhesive film has an enthalpy of fusion of at least about 25 J/g.

4. The self-supporting, heat curable adhesive film of claim 1, wherein the first polyurethane has a weight average molecular weight (Mw) of no less than about 50,000 g/mole.

11. An article comprising:

the self-supporting, heat curable adhesive film of claim 1 having a first surface and a second surface, and

a first substrate in direct contact with the first surface of the adhesive film.

12. The article of claim 11, wherein the first substrate is a metallic substrate or a non-metallic substrate.

15. An article comprising:

a first substrate,

a second substrate, and

the self-supporting, heat curable adhesive film of claim 1 disposed between the first substrate and the second substrate.

16. The article of claim 15, wherein one of the first substrate and the second substrate is a metallic substrate.

19. A method of making an article having a first substrate and a second substrate, the method comprising:

contacting a first substrate with a first major surface of the self-supporting, heat curable adhesive film of claim 1,

applying heat at a temperature of no greater than 55°

C. to the film before or after the film is applied to the first substrate,

contacting the second substrate with a second major surface of the self-supporting, heat curable adhesive film such that the second major surface is in direct contact with the second substrate to form the article, and

applying heat and pressure to the article.

20. The method of claim 19, wherein one of the first and the second substrates is a metallic substrate.

23. A method of making an article having a first substrate and a second substrate, the method comprising:

contacting a first substrate with a first major surface of the self-supporting, heat curable adhesive film of claim 1,

contacting the second substrate with a second major surface of the self-supporting, heat curable adhesive film such that the second major surface is in direct contact with the second substrate to form the article, and

applying heat and pressure to the article.

24. The method of claim 23, wherein one of the first and the second substrates is a metallic substrate.

27. The self-supporting, heat curable adhesive film of claim 1, wherein at least 30% by weight of the film is the sum of the weight of the first polyurethane and the weight of the second polyurethane.

5. A self-supporting, heat curable adhesive film derived from an aqueous composition comprising:

a surface-deactivated solid isocyanate,

a first polyurethane dispersion including a first polyurethane having functional groups reactive with isocyanate, and

a second polyurethane dispersion including a second polyurethane different from the first polyurethane, the second polyurethane being a carboxyl acid functional polyurethane having an acid number of from 10 to 30, and a unimodal weight average molecular weight (Mw) of no greater than about 50,000 g/mole.

6. The self-supporting, heat curable adhesive film of claim 5, wherein the adhesive film exhibits a 180 degree peel strength that is at least 30% greater than the 180 degree peel strength of Control I, when tested according to the Cured 180 Degree Peel Strength test method.

7. The self-supporting, heat curable adhesive film of claim 5, wherein the adhesive film has an enthalpy of fusion of at least about 25 J/g.

8. The self-supporting, heat curable adhesive film of claim 5, wherein the first polyurethane has a weight average molecular weight (Mw) of no less than about 50,000 g/mole.

9. The self-supporting, heat curable adhesive film of claim 5, wherein the first polyurethane includes functional groups comprising hydroxyl, amino, carboxylic acid, amide, mercaptan, and combinations thereof.

10. The self-supporting, heat curable adhesive film of claim 5, wherein the sum of the surface-deactivated solid isocyanate, the first polyurethane, the second polyurethane, and a third polymer amounts to at least about 95% by weight of the self-supporting adhesive film.

13. An article comprising:

the self-supporting, heat curable adhesive film of claim 5 having a first surface and a second surface, and

a first substrate in direct contact with the first surface of the adhesive film.

14. The article of claim 13, wherein the first substrate is a metallic substrate or a non-metallic substrate.

17. An article comprising:

a first substrate,

a second substrate, and

the self-supporting, heat curable adhesive film of claim 5 disposed between the first substrate and the second substrate.

18. The article of claim 17, wherein one of the first substrate and the second substrate is a metallic substrate.

21. A method of making an article having a first substrate and a second substrate, the method comprising:

contacting a first substrate with a first major surface of the self-supporting, heat curable adhesive film of claim 5,

applying heat at a temperature of no greater than 55°

C. to the film before or after the film is applied to the first substrate,

contacting the second substrate with a second major surface of the self-supporting, heat curable adhesive film such that the second major surface is in direct contact with the second substrate to form the article, and

applying heat and pressure to the article.

22. The method of claim 21, wherein one of the first and the second substrates is a metallic substrate.

25. A method of making an article having a first substrate and a second substrate, the method comprising:

contacting a first substrate with a first major surface of the self-supporting, heat curable adhesive film of claim 5,

contacting the second substrate with a second major surface of the self-supporting, heat curable adhesive film such that the second major surface is in direct contact with the second substrate to form the article, and

applying heat and pressure to the article.

26. The method of claim 25, wherein one of the first and the second substrates is a metallic substrate.