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 . A resin system comprising:
 (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 said resin precursor component, said thermoplastic particle and said 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 . 
     
     
         2 . A resin system according to  claim 1 , which is thermally curable using a curing temperature T C  wherein said curing temperature is attained with a cure ramp rate R CR . 
     
     
         3 . A resin system according to  claim 1 , wherein 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  for cure ramp rates R CR  in the range of 0.05° C./min to 3.0° C./min. 
     
     
         4 . A resin system according to  claim 1 , wherein 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  for cure ramp rates R CR  in the range of 0.05° C./min to 2.5° C./min 
     
     
         5 . A resin system according to  claim 1 , which is thermally curable using a curing temperature T C  in the range of from 140 to 200° C., and in one embodiment in the range of from 170 to 190° C. 
     
     
         6 . A resin system according to  claim 1 , wherein (T C +20) T PA  (T C −30)° C., wherein T PA  is the melting temperature of the polyamide particles and T C  is the curing temperature. 
     
     
         7 . A resin system according to  claim 1 , wherein the melting temperature T PA  of the polyamide particles is in the range of from 160 to 200° C. 
     
     
         8 . A resin system according to  claim 1 , wherein one curing agent is used and said curing agent is selected from 3,3′-diaminodiphenyl sulphone and 4,4′-diaminodiphenyl sulphone. 
     
     
         9 . A resin system according to  claim 1 , wherein a plurality of curing agents are used, wherein the curing agents are isophthalic dihydrazide and 4,4′-diaminodiphenyl sulphone. 
     
     
         10 . A resin system according to  claim 1 , wherein said multi-functional epoxy resin precursor(s) are selected from glycidyl derivatives of one or more of the group of compounds consisting of aromatic diamines, aromatic monoprimary amines, aminophenols, polyhydric phenols, polyhydric alcohols, polycarboxylic acids and the like, or mixtures thereof. 
     
     
         11 . A resin system according to  claim 1 , wherein said multi-functional epoxy resin precursor(s) are selected from O,N,N-triglycidyl-para-aminophenol (TGPAP); O,N,N-triglycidyl-meta-aminophenol (TGMAP); and N,N,N′,N′-tetraglycidyldiaminodiphenyl methane (TGDDM). 
     
     
         12 . A resin system according to  claim 1 , wherein said polyamide is selected from aliphatic polyamide-n and polyamide-n,m polymers, where n and m are independently selected from 10, 11 or 12, and particularly wherein n=m. 
     
     
         13 . A resin system according to  claim 1 , wherein said polyamide is selected from polyamide-10, polyamide-10,10, polyamide-11, polyamide-11,11, polyamide-12, polyamide-12,12, and polyamide-10-12, and in one embodiment from polyamide-11, polyamide-12, polyamide-10,10 and polyamide-10,12. 
     
     
         14 . A resin system according to  claim 1 , wherein the resin system comprises a combination of resin precursor component, thermoplastic particle and curing agent(s) selected from the group consisting of:
 (i) a resin precursor component comprising tri- or tetra-functional epoxy resin precursor(s), polyamide-12 particles and 3,3′-DDS;   (ii) a resin precursor component comprising tri- or tetra-functional epoxy resin precursor(s), polyamide-11 particles and 3,3′-DDS;   (iii) a resin precursor component comprising tri- or tetra-functional epoxy resin precursor(s), polyamide-10,10 particles and 4,4′-DDS; and   (iv) a resin precursor component comprising tri- or tetra-functional epoxy resin precursor(s), polyamide-12 particles, 4,4′-DDS and IDH.   
     
     
         15 . A resin system according to  claim 1 , wherein said thermoplastic particles are present in the resin system in the range of from about 2.5 to about 30 wt %, relative to the total combined weight of the thermoset resin precursor component plus thermoplastic particle component of the resin system. 
     
     
         16 . A resin system according to  claim 1  further comprising a toughening agent selected from thermoplastic aromatic polymers having a Tg of at least about 150° C., and in one embodiment selected from aromatic polyethersulphones. 
     
     
         17 . A composite material comprising the resin system of  claim 1  and reinforcing fibers. 
     
     
         18 . A process for producing a cured thermoset resin comprising the steps of:
 (i) selecting a 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) combining said resin precursor component with a thermoplastic polyamide particle component wherein the polyamide particles have a melting temperature T PA , and   (iii) curing the combination of said resin precursor component and said thermoplastic polyamide particle component with one or more curing agent(s), wherein said resin precursor component, said thermoplastic polyamide particle component and said curing agent(s) are selected such that gelation of the epoxy matrix during the cure cycle occurs at a gelation temperature T GEL  which is at or below T PA .   
     
     
         19 . A process according to  claim 18 , wherein curing is effected using a cure temperature T C  which is attained with a cure ramp rate R CR , and wherein gelation of the epoxy matrix during the cure cycle occurs at a gelation temperature T GEL  which is at or below T PA  for cure ramp rates R CR  in the range of 0.05° C./min to 3.0° C./min. 
     
     
         20 . A process according to  claim 19 , wherein said cure ramp rates R CR  are in the range of 0.05° C./min to 2.5° C./min. 
     
     
         21 . A process according to  claim 18 , wherein curing is effected using a cure temperature T C  in the range of from about 140 to about 200° C., and in one embodiment in the range of from 170 to 190° C. 
     
     
         22 . A process according to  claim 18 , wherein curing is effected using a curing temperature T C  and T C ≧T PA ≧(T C −30)° C.