JEC COMPOSITES MAGAZINE - Issue #67 - August/September 2011 - 42

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coating

New D-Iso/NPG gelcoat offers exceptional UV colour stability
The advanced D-Iso/NPG resin chemistry used in Crystic® Permabright gelcoat has set a new standard in long-term UV weathering performance. It provides significantly improved colour stability over existing marine Iso/NPG gelcoats. This innovative development from Scott Bader was showcased at this year’s JEC Composites show in Paris. Markets expected to benefit from this new technology are those where retaining a high level of aesthetic quality in exposed gelcoated surfaces is highly desirable, such as leisure marine, transportation and building.

DEAN BUGG, APPLICATIONS DEVELOPMENT MANAGER SCOTT BADER

prone to when there is a combination of heat and moisture.

his technical paper covers the development of Crystic® Permabright gelcoat and the approach taken by Scott Bader’s research scientists to weathering protection in relation to the overall gelcoat formulation. Comparative longterm testing was carried out in the critical performance areas of osmotic blistering and colour stability. The new advanced D-Iso/NPG polymer chemistry used as the base resin for the gelcoat was tested against established Iso/NPG and Iso gelcoat technologies. This paper also covers the production aspects of this new gelcoat with respect to its rheology, ease of application and repairability.

Effects of weathering

Weathering is a combination of physical degradation and chemical decomposition. A gelcoat has to combat surface oxidation and ultraviolet (UV) attack when exposed to sunlight. It also needs to resist hydrolysis, which a gelcoat is most

jec composites magazine / No67 August - September 2011

It is well known that gelcoats change colour after prolonged exposure to sunlight. Over time, the effects of weathering can be seen with the naked eye, such as a loss of gloss and chalking (whitening) for darker colours, and a gradual dulling and yellowing of white, off-white and cream colours. In many applications this is not aesthetically desirable. In some cases, where there has been prolonged exposure to strong sunlight, this eventually requires a refurbishment of the gelcoated surface.

applications may replace paint. For manufacturers, there are cost benefits to eliminating the need for a secondary painting operation.

Strategic gelcoat innovation project
Back in 2006, in response to these market needs, Scott Bader initiated a strategic gelcoat development project at its global R&D facility in Wollaston, England. History is repeating itself as this facility is in the same location where over 50 years ago pioneering chemists invented the first aerobic polyester resins and then went on to develop the first ever marine-grade resins and gelcoats. Wollaston is also the location of the Company’s head office and UK manufacturing facilities for its composite and specialty chemical products. The R&D team’s goal was to discover a next-generation gelcoat that would provide a step change in UV weathering performance to meet the demanding long-term weathering and hydrolysis resistance needs of exterior marine applications, while still offering

Market-led innovation

Scott Bader identified the market need for a superior gelcoat that could provide vastly improved gloss retention and colour stability. The leisure marine market, in particular, has been demanding much better long-term weathering performance from the gelcoats used on the decks and hulls of their prestigious luxury yachts which retail from hundreds of thousands to millions of euros. Other markets could also benefit and new gelcoat

JEC COMPOSITES MAGAZINE - Issue #67 - August/September 2011

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #67 - August/September 2011