Method for making composite structure with a surfacing film thereon

Patent metadata

Field	Value
Publication number	US-9925729-B2
Application number	US-201715458091-A
Country	US
Kind code	B2
Filing date	Mar 14, 2017
Priority date	Dec 9, 2011
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

A method for making a composite structure with a surfacing film thereon. The surfacing film is co-cured with fiber-reinforced resin composite materials. The surfacing film is formed from a curable resin composition containing an epoxy novolac resin, a tri-functional or tetra-functional epoxy resin, ceramic microspheres, an amine-based curing agent, particulate inorganic fillers; and a toughening component. The surfacing film exhibits high T g and high cross-linked density after curing, as well as high resistance to paint stripper solutions.

First claim

What is claimed is:

1. A method for making a composite structure comprising:
(a) providing a shapeable prepreg layup comprised of a plurality of prepreg layers arranged in a stacking arrangement, each prepreg layer comprising an uncured or partially cured resin matrix resin and reinforcing fibers;
(b) forming a surfacing film from a curable resin composition comprising:
an epoxy novolac resin having epoxy functionality of more than one;
a tri-functional or tetrafunctional epoxy resin;
ceramic microspheres;
a latent amine-based curing agent;
particulate inorganic fillers; and
a pre-react adduct formed by the reaction of diglycidylether of tetrabromo Bisphenol A, bisphenol A, and an elastomer selected from: amine-terminated butadiene acrylonitrile (ATBN); carboxyl-terminated butadiene acrylonitrile (CTBN); and carboxyl-terminated butadiene (CTB);
(c) placing the surfacing film into contact with the prepreg layup; and
(d) co-curing the surfacing film and the prepreg layup at a temperature within the range of 250° F.-350° F.

2. The method of claim 1 , wherein the epoxy novolac resin has the following structure:

where R═H and n=0-5, the tetra-functional epoxy resin is tetraglycidyl 4,4′-diaminodiphenylmethane, and the tri-functional epoxy is triglycidyl ether of aminophenol.

3. The method claim 1 , wherein the curable resin composition further comprises a copolymer of polyether sulfone (PES) and polyetherether sulfone (PEES).

4. The method of claim 1 , wherein the ceramic microspheres in the curable resin composition are hollow microspheres made of silica-alumina ceramic material.

5. The method of claim 1 , wherein the curable resin composition further comprises a bisurea as a curing accelerator.

6. The method claim 1 , wherein the curable resin composition further comprises a conductive material in particulate form in sufficient amount to provide a conductive surfacing film with a surface resistivity of less than 100 mΩ.

7. The method of claim 1 , wherein, after co-curing, the surfacing film exhibits a pencil hardness of 7H to 9H according to ASTM D-3363.

8. The method of claim 1 , further comprising applying a paint coating on the surfacing film after co-curing, wherein the adherence of the surfacing film to the paint coating is such that the painted surface exhibits substantially 0% paint loss after (a) being subjected to a paint adhesion test in accordance with ASTM D3359 under a dry condition or (b) immersing in de-ionized water at 75° F. for 7 days then being subjected to a paint adhesion test in accordance with ASTM D3359.

9. The method of claim 1 , further comprising applying a paint coating on the surfacing film after co-curing, wherein the adherence of the surfacing film to the paint coating is such that the painted surface exhibits substantially 0% paint loss as determined by the following procedure: subjecting the unpainted surfacing film to 1000 KJ/m 2 UVA radiation exposure, followed by subjecting the painted surface to a paint adhesion test in accordance with ASTM D3359 under a dry condition.

Assignees

• Cytec Tech Corp

Inventors

• Sang Junjie Jeffrey
• Kohli Dalip Kumar

Classifications

• B32B27/08

  of synthetic resin · CPC title

• C08L63/04

  Epoxynovolacs · CPC title

• B29K2105/0872

  Prepregs · CPC title

• B32B27/20

  using fillers, pigments, thixotroping agents · CPC title

• B32B2255/10

  on synthetic resin layer or on natural or synthetic rubber layer · CPC title