Modified Resin Systems for Liquid Resin Infusion Applications & Process Methods Related Thereto

Abstract

Embodiments of the invention are directed to modified resin systems for use in liquid resin infusion (LRI) processes, variations of LRI processes and other suitable processes. In one embodiment, the modified resin system includes a novel combination of at least one base resin, an amount of particles within a predetermined range and an amount of thermoplastic material within a predetermined range wherein, when combined, the modified resin system has an average viscosity below a threshold average viscosity at a specific temperature and a high level of toughness. The modified resin system may additionally include a curing agent and other suitable components. The modified resin system has been experimentally shown to exhibit a unique, controllable and constant morphology which may be at least partially responsible for imparting a required toughness and damage resistance to a finished composite without adversely impacting properties such as viscosity, potlife, cure temperature, glass transition temperature or tensile modulus of the modified resin system.

1 . A formulation, comprising:
 at least one base resin;   an amount of particles within a predetermined range in a carrier resin; and   an amount of thermoplastic material within a predetermined range wherein the base resin, the particles and the thermoplastic material are combined to form a modified resin system, the modified resin having an average viscosity below a threshold average viscosity within a predetermined temperature range.   
     
     
         2 . The formulation of  claim 1 , further comprising, an aniline-based amine compound curing agent. 
     
     
         3 . The formulation of  claim 1  wherein the base resin is one of epoxy, bismaleimide, cyanate ester or a combination thereof. 
     
     
         4 . The formulation of  claim 3  wherein the base resin comprises a combination of epoxies including at least one di- and tri-epoxy and at least one tetra-epoxy. 
     
     
         5 . The formulation of  claim 1  wherein the particles are one of functionalized core-shell rubber particles or hollow particles. 
     
     
         6 . The formulation of  claim 1  wherein the particles are one of non-functionalized core-shell rubber particles or hollow particles. 
     
     
         7 . The formulation of  claim 5  wherein the functionalized core-shell rubber particles comprise a core material which is one of polybutadiene-styrene, polybutadiene or a combination thereof, and a shell material which is one of silica, polymerized monomers of acrylic acid derivatives containing the acryl group including acrylic and poly(methyl methacrylate) or a combination thereof. 
     
     
         8 . The formulation of  claim 6  wherein the non-functionalized core-shell rubber particles comprise a core material which is one of polybutadiene-styrene, polybutadiene or a combination thereof, and a shell material which is one of silica, polymerized monomers of acrylic acid derivatives containing the acryl group including acrylic and poly(methyl methacrylate) or a combination thereof. 
     
     
         9 . The formulation of  claim 1  wherein, in a cured condition, the particles are substantially uniformly dispersed throughout the modified resin system. 
     
     
         10 . The formulation of  claim 1  wherein the thermoplastic material comprises one of phenoxy-based polymers, poly(ether sulfone) polymers, poly(ether ether sulfones), poly(methyl methacrylate) polymers, carboxylterminated butadiene acrylonitrile polymers, copolymers thereof or combinations thereof. 
     
     
         11 . The formulation of  claim 1  wherein the amount of thermoplastic material is below approximately 30% net weight of the modified resin system. 
     
     
         12 . The formulation of  claim 1  wherein, in a cured condition, at least the thermoplastic material is phase separated from the base resin. 
     
     
         13 . The formulation of  claim 1  wherein the threshold average viscosity is less than 5 Poise at a temperature of less than 180° C. 
     
     
         14 . A composite article, comprising:
 a structure having a predetermined shape, the structure having a plurality of layers of a fiber-based fabric, the structure having a targeted composite toughness within a predetermined range, wherein the toughness is at least partially imparted by a modified resin system during a process, the modified resin system including:   (i) at least one base resin;   (ii) an amount of particles within a predetermined range in a carrier resin; and   (iii) an amount of thermoplastic material within a predetermined range wherein the base resin, the particles and the thermoplastic material are combined to form the modified resin system, the modified resin having a average viscosity below a threshold average viscosity within a predetermined temperature range.   
     
     
         15 . The composite article of  claim 14  wherein the structure exhibits a high level of microcrack resistance. 
     
     
         16 . The composite article of  claim 14  wherein the process is a liquid resin infusion manufacturing process, a prepreg manufacturing process or a resin film infusion process. 
     
     
         17 . A formulation, comprising:
 a base resin comprising at least one epoxy;   a curing agent;   an amount of thermoplastic material; and   an amount of core-shell particles wherein the base resin, the curing agent, the thermoplastic material and the particles are combined to form the modified resin system, the modified resin having an amount of thermoplastic material of less than 30% net weight of the total weight of the modified resin system.   
     
     
         18 . The formulation of  claim 17  wherein, in a cured or vitrified condition, the thermoplastic material separates into aggregate domains from the base resin, each aggregate domain having an island-like morphology, the morphology evolving (i) during the later stages of a ramp to dwell temperature or (ii) after a ramp to dwell has been completed during the cure cycle. 
     
     
         19 . A manufacturing process, comprising:
 preparing a preform;   laying the preform within a mold;   heating the mold to a predetermined temperature; and   injecting a resin wherein the resin is a modified resin, the modified resin system comprising a combination of:
 (i) at least one base resin; 
 (ii) a curing agent; 
 (iii) an amount of particles within a predetermined range in a carrier resin; and 
 (iv) an amount of thermoplastic material within a predetermined range wherein the amount of thermoplastic material of the modified resin is less than 30% net weight of the total weight of the modified resin system. 
   
     
     
         20 . The manufacturing process of  claim 19  wherein the predetermined temperature of the mold is less than 180° C. 
     
     
         21 . The manufacturing process of  claim 19 , further comprising, ramping a temperature of the mold to 180° C. at a rate of up to 10° C. per minute. 
     
     
         22 . The manufacturing process of  claim 19  wherein, when the mold reaches 180° C., the temperature is held for between 30 minutes and 150 minutes.