It is known to repair chips and cracks in windscreens using ultra violet (UV) adhesives. Typically, UV adhesives are methacrylic resins which are cured using photoiniators based on benzophenone, a-hyroxyketones, a-amino-ketones or benzildimethyl-ketal which react to the ultraviolet part of the light spectrum, i. e. at a wavelength of approximately 360 nm.

The methacrylic resin is mixed with the photoinitiator and the resulting mix is applied to the crack or chip in the windscreen. After the mix has been suitably worked into the crack or chip to fill it and to blend in with the glass, a UV light is positioned over the area of the repair to activate the initiator and bring about curing of the resin.

It will be appreciated that the use of UV light to bring about curing of the adhesive represents a potential health hazard since careless and prolonged exposure to UV light can cause eye damage and the development skin cancers or melanomas.

UV adhesives are also used for bonding glass as, for example, is required in the manufacture of decorative glass inserts in which decoratively shaped bevelled glass pieces are bonded to a glass substrate.

It is an object of the present invention to provide a bonding system for repairing and bonding glass which obviates or at least substantially mitigates the health hazard posed by the use of UV adhesives.

According to a first aspect the present invention there is provided a bonding system for repairing glass and for bonding pieces of glass together comprising an adhesive and a photoinitiator which is activated by light in the white/blue area of the spectrum.

It will be understood that by using a photoinitiator which is activated by light in the white/blue area of the spectrum there is no risk of exposure to potentially hazardous UV light. This is a significant improvement on the conventional UV activated systems where, by virtue of the fact that the consequences of exposure to UV light are not felt immediately, users cannot be relied upon to always follow good health and safety practices. Preferably, the photoinitiator is an acyl phosphine oxide such as diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, CAS-no. 75980-60-8, also known by the trade name lucerin TPO.

Preferably, the adhesive is a methacrylic adhesive, such as hydroxyethyl methacrylate. These contain no glass particles making them optically clear. It is preferable that the adhesive is flexible so that glass can freely expand and contract without shattering.

The system of the present invention removes the need to use potentially dangerous UV adhesives in the windscreen repair industry, the decorative glass bonding industry and the aircraft canopy repair market. The present invention may

also be used to laminate glass and produce automotive vehicle windscreens.

Moving the cure area of the chemicals into the safe blue/visible area of the spectrum avoids the problems associated with the use of UV adhesives.

The invention solves the problem of the hazards associated with UV systems by initiating curing of the adhesives using a photoinitiator which only absorbs photons in the white/blue light area of the spectrum. This will mean that an operator working with the bonding system of the present invention need have no fear of exposure to potentially dangerous UV light.