Thermosetting adhesive films including a fibrous carrier

• US 10,577,522 B2
• Filed: 07/25/2014
• Issued: 03/03/2020
• Est. Priority Date: 07/26/2013
• Status: Active Grant

• Current Assignee: Zephyros, Inc.
• Original Assignee: Zephyros, Inc.
• Inventors: Awkal, Michel, Chene, Morgan
• Primary Examiner(s): Freeman, John D
• Application Number:
  US14/907,160
• Publication Number:
  US 20160160092A1
• Time in Patent Office: 2,048 Days
• CPC Class Codes: C08J 2363/00 Characterised by the use of epoxy resins; Derivatives of epoxy resins
• CPC Class Codes: C08J 2367/00 Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
• CPC Class Codes: C08J 2463/00 Characterised by the use of epoxy resins; Derivatives of epoxy resins
• CPC Class Codes: C08J 5/128 Adhesives without diluent
• CPC Class Codes: C09J 163/00 Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
• CPC Class Codes: C09J 171/00 Adhesives based on polyethers obtained by reactions forming an ether link in the main chain based on polyacetals C09J159/00; based on epoxy resins C09J163/00; based on polythioether-ethers C09J181/02; based on polyethersulfones C09J181/06; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 2301/122 the adhesive layer being present only on one side of the carrier, e.g. single-sided adhesive tape
• CPC Class Codes: C09J 2301/124 the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
• CPC Class Codes: C09J 2301/414 presence of a copolymer
• CPC Class Codes: C09J 2400/263 in the substrate
• CPC Class Codes: C09J 2451/00 Presence of graft polymer
• CPC Class Codes: C09J 2461/00 Presence of condensation polymers of aldehydes or ketones
• CPC Class Codes: C09J 2463/00 Presence of epoxy resin
• CPC Class Codes: C09J 2463/006 in the substrate
• CPC Class Codes: C09J 2467/006 in the substrate
• CPC Class Codes: C09J 2471/00 Presence of polyether
• CPC Class Codes: C09J 2477/006 in the substrate
• CPC Class Codes: C09J 2479/086 in the substrate
• CPC Class Codes: C09J 5/00 Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
• CPC Class Codes: C09J 5/06 involving heating of the applied adhesive
• CPC Class Codes: C09J 7/00 : Adhesives in the form of films or foils
• CPC Class Codes: C09J 7/10 : without carriers
• CPC Class Codes: C09J 7/21 : Paper; Textile fabrics
• CPC Class Codes: C09J 7/35 : Heat-activated
• CPC Class Codes: Y10T 428/1476 : Release layer
• CPC Class Codes: Y10T 428/31515 : As intermediate layer

Abstract

Flexible films comprise an adhesive layer and a fibrous supporting layer and the thermosetting adhesive materials which are non-tacky to the touch are storage stable at room temperature and can be cured at elevated temperature with a short cure time and can be cured to produce a tough flexible adhesive layer including bonding to oily surfaces, the materials are particularly useful in bonding together dissimilar substrates where they can reduce the formation of galvanic corrosion.

Claims

1. A curable thermosetting adhesive film which is:

a) flexible prior to cure so that flaws in the adhesive film are protected against propagation; and

b) storage stable at room temperature,

wherein the adhesive film comprises an adhesive layer having a density of from 1.1 to 1.5 g/ml and a fibrous supporting layer;

wherein the adhesive layer comprises;

i) a phenoxy resin;

ii) an elastomer/epoxy resin adduct;

iii) an epoxy resin;

iv) a core shell material;

v) a curing agent; and

vi) one or more corrosion inhibitors;

wherein the adhesive film has an uncured thickness between 0.2 and 3.0 mm;

wherein the adhesive film prevents galvanic corrosion when bonding together via the adhesive layer two or more substrates having different conductivities and different coefficients of thermal expansion;

wherein the adhesive layer is coated with a tacky thermosetting resin that is a liquid so that the adhesive film can be removably adhered to a surface at ambient temperature; and

wherein the tacky thermosetting resin can be cured by the curing agent of the adhesive layer.

2. The adhesive film according to claim 1, wherein the adhesive film can be cured in no more than 45 minutes at a temperature no higher than 190°

C.

3. The adhesive film according to claim 2, wherein the adhesive film forms an adhesive bond with oily surfaces.

4. The adhesive film according to claim 2, wherein the adhesive film can be cured at a temperature in the range 130°

C. to 190°

C.

5. The adhesive film according to claim 2, wherein the adhesive layer is foamable.

6. The adhesive film according to claim 1, wherein the adhesive layer contains from 15 to 40 wt % of the phenoxy resin, from 5 to 40 wt % of the elastomer/epoxy resin adduct, and from 5 to 25 wt % of the core shell polymer.

7. The adhesive film according to claim 6, wherein the fibrous supporting layer is selected from a woven mat, a knit mat, or a random mat and is derived from glass, polyester, polyimide, carbon, or aramid fibres.

8. The adhesive film according to claim 7, wherein the fibrous supporting layer has a thickness of from 10 to 500 μ

m.

9. The adhesive film according to claim 7, wherein the fibrous supporting layer has an area weight of from 10-200 grams/square metre.

10. The adhesive film according to claim 7, wherein the fibrous supporting layer is an electrically non-conducting, non-woven glass fibre, glass fibre scrim, polyester, or aramid fibres having a binder.

11. The adhesive film according to claim 6, wherein the adhesive layer is uncured and the uncured adhesive layer coated with the tacky thermosetting resin is on one or both sides of the fibrous supporting layer.

12. The adhesive film according to claim 1, wherein the fibrous supporting layer has a porosity of from 1-1000 μ

m.

13. The adhesive film according to claim 1, wherein the adhesive layer is uncured, and the uncured adhesive layer coated with the tacky thermosetting resin is on one or both sides of the fibrous supporting layer.

14. The adhesive film according to claim 1, wherein the tacky thermosetting resin is free of a curing agent.

15. The adhesive film according to claim 1, wherein the tacky thermosetting resin coats the adhesive layer in an amount of from 2 to 10 grams per square meter.

16. A cured adhesive film derived from the adhesive film according to claim 1.

17. A process of using the adhesive film according to claim 1 for bonding together the two or more substrates, including locating the adhesive film onto a first substrate and contacting the first substrate with a second substrate with the adhesive film located therebetween, wherein the first substrate comprises a material that is dissimilar from that of the second substrate.

18. A process of using the adhesive film according to claim 1 for the bonding of metals to fibre reinforced resin composites, including locating the adhesive film onto a metallic substrate and afterward contacting the adhesive film with a fibre reinforced resin composite substrate.

19. The process according to claim 18, wherein the fibre reinforced resin composite is a glass, carbon, or aramid fibre reinforced epoxy or polyester based resin.