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Crestabond primer-less structural adhesives gain DNV-GL approval for maritime applications

News International-French

19 May 2015

Two grades from Scott Bader’s range of Crestabond primer-less methacrylate structural adhesives have now been independently approved by DNV-GL as ‘Duromeric’ adhesives, suitable for use in the joining of components for marine applications.

DNV-GL is the a classification society and a recognized advisor for the maritime industry. Both Crestabond M1-30 and M1-60 grades passed test criteria which satisfied DNV-GL of their performance capabilities for structural bonding applications in FRP boatbuilding within stipulated operational limits and for specific substrates. According to this new approval, both grades are classified as being fully compatible to bond three key base materials: aluminium; glass fibre reinforced polyester resins; and glass fibre reinforced epoxy resins.

Crestabond M1-30 and M1-60 are toughened, two component 10:1 primer-less acrylic adhesives, developed in-house by Scott Bader for structurally bonding composites, thermoplastics and metals. The range has been specially designed to meet the bonding requirements of most assembly operations. According to published Scott Bader technical information, Crestabond adhesives demonstrate excellent impact, peel, shear, compressive strength and fatigue resistance properties across all bonded parts. The two approved grades provide a choice of working and fixture times as needed. Crestabond M1-30 offers a working time of 25-35 minutes and a fixture time of 60-80 minutes. For larger and more complex assemblies, Crestabond M1-60 offers a longer shop floor working time of up to 70 minutes and a fixture time of 150-180 minutes. Typical material property values (tested to ASTM D638) of 17-20 MPa for tensile strength, 750-1000 MPa for tensile modulus and an elongation of >100% for CrestabondM1-30 are quoted in Scott Bader’s technical data sheet; for M1-60, tensile strength figures of 16-18 MPa and a tensile modulus of 650-850MPa are quoted, also with an elongation of >100%.

Being a primer-less adhesive, a key shop floor benefit of all Crestabond grades is that minimal surface cleaning and preparation of substrates is required. This helps to reduce overall production costs and increase productivity. To further assist shop floor efficiency, productivity and cost control, various packaging options are available: Crestabond M1-30 is supplied in pre-packed 400ml co-axial cartridges for hand guns, and in 18Kg plastic pails or 180Kg drums, which are ideal for bulk dispensing metering systems. Crestabond M1-60 is also available in 825ml side by side cartridges.

Launched in 2010, Crestabond has been used for several years by a number of specialist composite boatbuilders, including Yeovil based Ribcraft Ltd in the UK, which for many years has specified Crestabond for a variety of structural hull, deck and component bonding applications in its professional and leisure rib boats.

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