Thermoplastic Toughening Material And Related Method

Abstract

A non-fibrous, apertured membrane comprises at least one thermoplastic polymeric material and has a discrete porous structure. The membrane is soluble in the thermoset matrix polymer of a composite material.

1 . A method for locating insoluble moieties between the fibrous layers of a composite material wherein said composite material comprises a plurality of fibrous layers and a thermosetting resin, said method comprising the steps of:
 providing a membrane comprising a thermoplastic polymer that dissolves in said thermosetting resin during curing of said resin and one or more insoluble moieties that do not dissolve in said thermosetting resin during curing of said resin; and   locating said membrane between said fibrous layers prior to curing of said thermosetting resin.   
   
   
       2 . A method for locating insoluble moieties between the fibrous layers of a composite material according to  claim 1  wherein said membrane comprises a plurality of apertures extending through said membrane. 
   
   
       3 - 46 . (canceled) 
   
   
       47 . A method for locating insoluble moieties between the fibrous layers of a composite material according to  claim 1  wherein said thermosetting resin is selected from the group consisting of epoxy resins and bismaleimide resins. 
   
   
       48 . A method for locating insoluble moieties between the fibrous layers of a composite material according to  claim 47  wherein said thermoplastic polymer is polyethersulfone. 
   
   
       49 . A method for locating insoluble moieties between the fibrous layers of a composite material according to  claim 1  wherein said insoluble moieties are selected from the group consisting of toughening particles, intumescents, pigments, mould release agents, nano-sized particles and conducting particles. 
   
   
       50 . A method for locating insoluble moieties between the fibrous layers of a composite material according to  claim 49  wherein said toughening particles comprise a polymer selected from the group consisting of polyamide and polyetherimide. 
   
   
       51 . A method for locating insoluble moieties between the fibrous layers of a composite material according to  claim 2  wherein from 5 to 50 percent of said membrane comprises said apertures. 
   
   
       52 . A method for making a composite material that comprises a plurality of fibrous layers and a thermosetting resin, said method comprising the steps of:
 providing a plurality of fibrous layers;   forming an assembly wherein a membrane is located between said fibrous layers, said membrane comprising a thermoplastic polymer that dissolves in said thermosetting resin during curing of said resin and one or more insoluble moieties that do not dissolve in said thermosetting resin during curing of said resin;   incorporating said thermosetting resin into said assembly to form a curable composite material.   
   
   
       53 . A method for making a composite material according to  claim 52  wherein said step of incorporating said thermosetting resin into said assembly comprises the step of adding said thermosetting resin to said fibrous layers prior to formation of said assembly. 
   
   
       54 . A method for making a composite material according to  claim 52  wherein said step of incorporating said thermosetting resin into said assembly comprises the step of adding said thermosetting resin to said fibrous layers after forming said assembly. 
   
   
       55 . A method for making a composite material according to  claim 52  which includes the additional step of curing said curable composite material. 
   
   
       56 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material wherein said composite material comprises a plurality of fibrous layers and a thermosetting resin, said membrane comprising:
 a thermoplastic polymer that dissolves in said thermosetting resin during curing of said resin and one or more insoluble moieties that do not dissolve in said thermosetting resin during curing of said resin.   
   
   
       57 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material according to  claim 56  wherein said membrane has a discrete porous structure. 
   
   
       58 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material according to  claim 56  wherein said membrane comprises a plurality of apertures extending through said membrane. 
   
   
       59 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material according to  claim 57  wherein said membrane comprises a plurality of apertures extending through said membrane. 
   
   
       60 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material according to  claim 57  wherein said discrete porous structure comprises discrete pores having an average pore size of about 40 microns. 
   
   
       61 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material according to  claim 58  wherein from 5 to 50 percent of said membrane comprises said apertures. 
   
   
       62 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material according to  claim 56  wherein said insoluble moieties are selected from the group consisting of toughening particles, intumescents, pigments, mould release agents, nano-sized particles and conducting particles 
   
   
       63 . A membrane for use in locating insoluble moieties between the fibrous layers of a composite material according to  claim 62  wherein toughening particles comprise a polymer selected from the group consisting of polyamide and polyetherimide and said thermoplastic polymer is polyether sulfone. 
   
   
       64 . A composite material comprising a plurality of fibrous layers and a thermosetting resin, said composite material further comprising a membrane according to  claim 56  located between said fibrous layers. 
   
   
       65 . A cured composite material according to  claim 60  wherein said thermosetting resin has been cured.