After
45 Years in the Wilderness –
Core Shell Rubber Tougheners for
Thermoset Resins Have Finally Arrived
Douglas
J. Sober
Kaneka Texas Corporation
Core Shell Rubber toughening agents (CSR) were developed in the early 1960s. Although the consumption of CSR is about 1 million metric tons annually, the application of these toughening agents has been almost entirely in the thermoplastic world. The pioneering CSR were difficult to mix into the thermosetting recipes and the particles eventually agglomerated resulting in less than optimum homogeneity in the composite part or adhesive. Companies that initially tried CSR were disappointed and the technology languished in low volumes in less sophisticated applications……….until now !
Kaneka Texas Corporation has developed a proprietary process for dispersing CSR domains into various thermosetting resins. The CSR nano-particles are perfectly dispersed and remain so during storage under a variety of conditions and after the formulating process is complete. All residual surfactants and ionic species are removed during the “MX Process”. The resulting FR-4 composite exhibits improved inter-laminar adhesion, fracture toughness and lap shear strength without depressing the glass transition temperature or other thermal properties related to the cross-ink density. The CSR particles are supplied as a 25% concentrate in an epoxy resin chosen by the formulator such as a liquid or solid Bis-A epoxy, multifunctional epoxy, epoxidized novolaks, phenolic resins and vinyl esters thus minimizing initial development work. This presentation discusses the merits and use of these novel toughening agents for thermosetting systems.
Doug Sober has 30 years experience in formulating epoxy systems for base materials for printed circuit board applications and composites. He has a BA in Chemistry from Clarion State College and an MS in Organic Chemistry from The Ohio State University.
Since April
2005, Doug has been the Marketing Specialist/Epoxy for Kaneka Texas Corporation,
a supplier of high performance toughening agents for thermoset resin systems.
Specific applications include adhesives, composites, surface protection, electrical
casting and copper-clad laminates. Previously he was the North American Sales
Manager for Bakelite Epoxy Polymers. Doug has been active in the trade association
related to the electronics supply chain, IPC. Doug has held the position the
Base Materials General Chairman since 1992 and has been a past chairman of
the TAEC, the highest technical position within the organization. Doug was
inducted into the IPC Hall of Fame in 2004 joining 16 other recipients since
1977.
Tele: 713-503-1558
E-Mail: dsober@kanekatexas.com