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Adhesives help build luxury coach

Fig. 1 The adoption of new materials in this Hestair Duple luxury coach had led to extensive use of adhesive bonding in its construction

Six separate adhesives products have been used in the manufacture of the Hestair Duple 425 coach shown in Fig. 1.

Bostik 5341, a two-part polyurethane adhesive, has been used to bond the single-sheet sides of the coach to its spaceframe (which has been used in place of a conventional chassis). A polyurethane adhesive was chosen because it does not dry out and crack, thus helping to prevent leaks and subsequent corrosion. Bostik 5341 is said to cure very quickly, which prevents slippage of the panels, and to have the necessary f lexibi l i ty to ensure a tough bond.

One-part Bostik 2639, another polyurethane adhesive, was used for bonding the wooden floor of the coach to the metal framework and for bonding and sealing the GRP roof.

The other adhesive products, all from Bostik, were: Autoseal 160 for sealing the windscreen and windows; M890 and M894 for bonding GRP air-conditioning trunking and luggage racks to the spaceframe; and L936 for attaching the floor coverings.

The design of the Hestair luxury coach allowed for the adoption of new materials in its construction.

Bostik Limited, Ulverscroft Road, Leicester, LE4 6BW, UK.

Fast-curing adhesives developed for specific applications

Loctite UK now offers cyanoacrylate adhesives in the Prism range with specially developed properties:

• Prism 401, described as an ultrafast curing adhesive, is particularly suited for use with porous materials such as wood, fabrics and paper;

• Prism 405, a toughened cyanoacrylate, is offered for bonding metals where high peel strengths are required;

• Prism 460 has been developed with low odour and low bloom properties for use with dark, shiny components, electronic assemblies and in enclosed working environments; and

• Prism 499, in gel form for use on vertical or poorly matched surfaces, also may be used at temperatures up to 120°C.

Loctite UI~ Watchmead, Welwyn Garden City, Herts, AL 7 1JB, UIC

Torridge Bridge constructed using epoxy resins

Precast concrete glued segmental construction is being used to form the bridge over the river Torridge, which itself forms part of the Bideford Bypass, North Devon, UK, due to be completed in May 1987.

Approximately 650 m long, the bridge comprises 250 concrete box segments, varying in weight between 50 and 105 tonnes. Sikadur 31 SBA, a solvent-free, two-part epoxy resin system, was chosen to glue these segments together. Once in position, the grit- blasted faces of each pair of match- cast segments are sealed with a 2 mm thick coating of Sikadur 31 SBA. Use of the resin is said to lubricate the surface of each segment sufficiently to permit precise positioning. It is also said to develop full strength quickly, not only allowing construction to continue to schedule but also ensuring that compression, shear and tensile strengths are evenly transmitted between segments. Unaffected by high humidity, the adhesive may be applied to damp surfaces and wil l form an effective moisture seal between segments.

Sikadur 31 SBA is from Sika Inertol, Watchmead, Welwyn Garden City, Herts, AL 7 I B a UK. Further information on the construction of the bypass may be obtained from: The Cement and Concrete Association, Wexham Springs, Slough, SL3 6PL, UK.

Corrigendum

Readers are requested to note that, in the paper entitled 'Use of the wedge test to estimate the lifetime of an adhesive joint in an aggressive environment" by J. Cognard, published in Volume 6 Number 4 (October 1986), Equation (1) on page 215 should read:

3Ee2h 3

Ws - 16/04

Apologies are extended to any reader to whom this error has caused inconvenience.

INT.J.ADHESlON AND ADHESIVES APRIL 1987 59