ADVANCING ADHESIVES: New Adhesive Features Longer Working Time
The Crystic® Crestomer® range of high-performance urethane acrylate structural adhesives from Scott Bader Composites has recently been extended to include a new grade for longer working times. The new product, Crystic Crestomer 1153PA, is pre-accelerated and methyl ethyl ketone peroxide (MEKP)-cured (2% w/v), and can be supplied in 25-kg (55-lb) and 200-kg (441-lb) containers. Crestomer structural adhesives are used by major marine craft manufacturers in Europe, the Middle East, South Africa, the U.S. and China.
Crystic Crestomer 1153PA is aimed at composite manufacturers of larger fiber glass-reinforced panel (FRP) structures, typically with dimensions of over 25 m (82 ft), that would benefit from a longer adhesive open working time (up to 90 minutes) during production. The longer working time is also of benefit to fabricators operating in high local daytime ambient temperatures (above 25°C/77°F). Customers in high-temperature climates can use the longer open time Crestomer 1153PA during the hottest months and switch to Crestomer 1152PA during the cooler times of the year.
As with all products in the Crestomer range, this new addition was also submitted to Lloyds Register for testing. Crestomer 1153PA successfully gained Lloyds Acceptance (Statement of Acceptance MATS/1785/3), which covers structural adhesives for use in critical FRP bonding applications. Crestomer 1153PA has excellent adhesion to FRP materials; typical FRP-to-FRP lap shear bond joint strengths of 10 MPa have been recorded under BS ISO 4587:2003, with the limiting factor being failure of the substrate, not the adhesive.
This performance was demonstrated in 2009 when Schat-Harding, a leading lifeboat and evacuation system supplier for the offshore, cruise, and shipping industries, set a new 55-m (180-ft) freefall drop world record for a lifeboat with its FF1200 model. The hull bulkheads of the lifeboat’s highly engineered, fiber-reinforced and sandwich composite design were bonded using Crestomer 1152PA. Despite its “all up” weight of 30 metric tons, the FF1200 lifeboat surfaced after having plunged 11 m (36 ft) under the water without suffering any external or internal damage. In addition, the FF1200 was the first vessel to meet all of the new Norwegian Oil Industry Association (OLF) design criteria for lifeboats in the Norwegian offshore sector, which is generally regarded as the most stringent offshore safety standard.
Scott Bader’s R&D team developed Crestomer 1153PA by modifying the long-established Crestomer 1152PA grade, which is specified for a variety of demanding hull and deck structural bonding marine applications. Also MEKP-cured, the 1152PA grade differs from 1153PA only in having a shorter open working time (50 minutes). Both Crestomer grades have the same rheology, which offers an adhesive that can be easily applied either manually or with suitable dispensing equipment.
About Scott BaderEstablished in 1921, Scott Bader is a multinational chemical company that employs 560 people worldwide. It is a common trusteeship company with a strong commitment to supporting its customers, workforce and the environment.
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