Peel ply, method of surface preparation and bonding composite structures using the same

Patent metadata

Field	Value
Publication number	US-9473459-B2
Application number	US-201213678595-A
Country	US
Kind code	B2
Filing date	Nov 16, 2012
Priority date	Dec 30, 2011
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

A resin-rich peel ply that does not leave behind residual fibers after peeling and can work well with different resin-based composite substrates. The resin-rich peel ply is composed of a woven fabric impregnated with a resin matrix different from the resin matrix of the composite substrate. The peel ply is designed such that, upon manual removal of the peel ply from the composite substrate's surface, a thin film of the peel ply resin remains on the composite substrate's surface to create a bondable surface capable of bonding with another composite substrate, but no fibrous material from the woven fabric remains on the same surface.

First claim

What is claimed is:

1. A peel ply system for surface preparation of various composite substrates, said system comprising:
(a) a composite substrate comprising reinforcing fibers impregnated with a cured, first resin matrix; and
(b) a removable, resin-rich peel ply adhered to a surface of the composite substrate, said peel ply comprising a woven fabric impregnated with a cured, second resin matrix different from the first resin matrix,
whereby, upon manual removal of the peel ply from the composite substrate's surface, a thin film of the second resin matrix remains on the composite substrate's surface to provide a bondable surface capable of co-bonding and secondary bonding with another composite substrate,
wherein said second resin matrix is formed from a resin composition comprising:
at least one epoxidized novolac resin having epoxy functionality of at least 2;
di-functional epoxy resin selected from diglycidyl ethers of polyhydric phenols;
tri-functional epoxy resin selected from triglycidyl ethers of aminophenols;
a curing agent; and
inorganic filler particles;
wherein said peel ply has a resin content of at least 20% by weight based on the total weight of the peel ply, and
wherein said woven fabric comprises a plurality of yarns woven in a weaving pattern, said yarns having warp tensile strength of ≧70 lbf/in, fill tensile strength of ≧40 lbf/in, warp linear mass density within the range of 50-250 deniers, and fill linear mass density within the range of 50-250 deniers.

2. The system of claim 1 , wherein said yarns have warp tensile strength of ≧80 lbf/in, fill tensile strength of ≧50 lbf/in, warp linear mass density within the range of 70-230 deniers, and fill linear mass density within the range of 70-230 deniers.

3. The system of claim 1 , wherein the remaining thin film of the second resin matrix has a thickness of about 2%-15% of the original thickness of the peel ply prior to removal.

4. The system of claim 1 , wherein the resin composition comprises at least one epoxidized novolac resin represented by the following structure:

wherein n is an integer from 0 to 8, R═H or CH 3 .

5. The system of claim 4 , wherein the resin composition further comprises a dicyclopentadiene-containing novolac epoxy resin represented by the following structure:

wherein n=an integer from 0 to 7.

6. The system of claim 1 , wherein said woven fabric has a fabric weight within the range of 50-250 gsm.

7. The system of claim 6 , wherein said woven fabric has a fabric weight within the range of 70-220 gsm.

8. The system of claim 1 , wherein said woven fabric has a fabric thickness in the range of 50-250 μm.

9. The system of claim 8 , wherein said woven fabric has a fabric thickness in the range of 100-200 μm.

10. The system of claim 1 , wherein the yarns of the woven fabric are made of materials selected from the group consisting of: polyesters, polyethylene, polypropylene, nylon, elastomeric materials, polyaramids, polyimides, polyethyleneimine (PEI), polyoxazole, polybenzimidazole (PBI), polyether ether ketone (PEEK), and glass.

11. The system of claim 1 , wherein said peel ply has a resin content within the range of 20%-50% by weight based on the total weight of the peel ply.

12. The system of claim 1 , wherein said peel ply has a glass transition temperature (T g ) of ≧140° C.

13. The system of claim 12 , wherein said peel ply has a glass transition temperature (T g ) within the range of 140° C.-200° C.

14. The system of claim 1 , wherein the curing agent is selected from the group consisting of BF 3 , BCl 3 , and complexes thereof.

15. The system of claim 1 , wherein said second resin matrix is formed from a resin composition comprising:
epoxy phenol novolac resin having epoxy functionality of at least 2;
dicyclopentadiene-containing epoxy novolac resin having epoxy functionality of at least 2;
diglycidyl ether of bisphenol A;
triglycidyl ether of aminophenol;
a curing agent selected from the group consisting of BF 3 , BCl 3 , and complexes thereof; and
fumed silica.

16. The system of claim 1 , wherein the novolac resins are making up at least 20% by weight based on the total weight of the composition.

Assignees

• Cytec Tech Corp

Inventors

• Zhao Yiqiang
• Kohli Dalip Kumar
• Shah Kunal Gaurang

Classifications

• B32B5/024

  Woven fabric · CPC title

• B29C65/5028

  being textile in woven or non-woven form · CPC title

• B29C66/73161

  Roughness or rugosity · CPC title

• B29C65/4835

  Heat curing adhesives · CPC title

• G06F3/04842

  Selection of displayed objects or displayed text elements (G06F3/0482 takes precedence) · CPC title