Thermoset resin composite materials comprising inter-laminar toughening particles

Abstract

A resin system containing: (i) a thermosetting resin precursor component comprising one or more multi-functional epoxy resin precursor(s) having a functionality of at least three, preferably wherein said precursor(s) are selected from a tri-functional epoxy resin precursor and/or a tetra-functional epoxy resin precursor; (ii) a thermoplastic polyamide particle component wherein the polyamide particles have a melting temperature T PA ; and (iii) one or more curing agent(s), wherein the resin precursor component, the thermoplastic particle and the curing agent(s) are selected such that gelation of the epoxy matrix during the cure cycle of the resin system occurs at a gelation temperature T GEL which is at or below T PA .

1 - 17 . (canceled) 
     
     
         18 . A process for producing a cured composite comprising the steps of:
 (i) forming a resin composition comprising: (a) a resin precursor component consisting of a tri-functional epoxy resin precursor and a tetra-functional epoxy resin precursor, (b) 3,3′- or 4-,4′-diaminodiphenylsulphone as a curing agent, (c) an aromatic polyethersulphone, and (d) particles of polyamide-11 or polyamide-12 having a melting temperature T PA ,   (ii) combining said resin composition with reinforcing fibres to form a composite material, and   (iii) curing the composite material in a cure cycle in which a cure temperature T C  is attained with a cure ramp rate R CR  in the range of 0.05° C./min to 3.0° C./min,   wherein the cure temperature T C  is in the range of 170° C. to about 190° C., and   wherein the gelation of the resin composition during the cure cycle occurs at a gelation temperature T GEL  which is below T PA .   
     
     
         19 . (canceled) 
     
     
         20 . The process according to  claim 18 , wherein said cure ramp rate R CR  is in the range of 0.05° C./min to 2.5° C./min. 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . The process according to  claim 18 , wherein said tri-functional epoxy resin precursor is O,N,N-triglycidyl-para-aminophenol (TGPAP) or O,N,N-triglycidyl-meta-aminophenol (TGMAP); and said tetra-functional epoxy resin precursor is N,N,N′,N′-tetraglycidyldiaminodiphenyl methane (TGDDM). 
     
     
         24 . The process according to  claim 18 , wherein the resin composition comprises 4,4′-diaminodiphenyl sulphone (4,4′-DDS) as curing agent and further comprises isophthalic acid dihydrazide (IDH).