JEC COMPOSITES MAGAZINE - Issue #43 - September 2008 - 39

FEATURE “Marine” Gelcoat Imedge® polymer coating and polymer barrier technologies As shown by market analysis and discussions with boat builders, the marine industry needs new coating and barrier coat technologies that feature improved crack resistance compared with conventional gelcoats, while creating enhanced surface profiles and high-quality, fade-resistant deep colours. PAUL DARBY, IMEDGE® PROJECT LEADER EUROPE, CRAY VALLEY FREDERIC BAUCHET, NEW PRODUCT DEVELOPMENT MANAGER, COOK COMPOSITES & POLYMERS (CCP) More information Together, Cray Valley and its sister company Cook Composites & Polymers (CCP) are the world’s leading gelcoat producer with manufacturing facilities all around the globe (North and South America, Europe, Africa and Asia-Pacific). Cray Valley not only offers gelcoats but also many speciality products such as unsaturated polyester, vinyl ester and hybrid resins, low profile additives, bonding pastes, tooling solutions, VOC-free cleaning agents, and a strong local service to the composite industry. The starting point was a fundamental consideration of the sources and stresses that initiate such cracks, which include flexural, impact and thermal stresses. Such stresses are more likely to produce cracks when the gelcoat is too thick, the laminate is under-cured or the part is poorly designed. The next step was to establish laboratory test methods to simulate the stresses and resultant cracking. A combination of elongation to first audible crack, flexion to first audible crack and reverse impact testing was used. Flexural and impact testing results are shown below (figures 2 and 3). T he IMEDGE® products came about as a result of focused discussions with marine market leaders, who defined the following two top priorities: 1) reducing external part cracking in order to lower in-process and warranty costs, and 2) producing fade-resistant dark colours (MACT compliant, i.e. with a Low Styrene Content, for North-American markets). Obviously, these improvements would need to be achieved without compromising any other properties. Crack resistance A complementary system combining polymer coating (PCT 600 Series) and polymer barrier (PBT 200 Series) technologies was developed to address cracking issues. PCT 600 replaces conventional gelcoats, and PBT 200 replaces vinyl ester barrier coats or glass-fibre reinforced vinyl ester skin coats. This system has a superior toughness and impact resistance in comparison with industry standard gelcoats and barrier coats. In addition to crack resistance, these new technologies offer a number of other benefits including improved gloss retention after weathering, improved water resistance, and improved wear and scratch resistance. UV resistance in terms of gloss and colour retention is illustrated in the graph below (figure 1). Fig. 1: UV resistance Fig. 2: Flexural testing No43 September 2008 / JEC Composites Magazine 39

JEC COMPOSITES MAGAZINE - Issue #43 - September 2008

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #43 - September 2008