Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2002-06-17
2004-07-27
Foelak, Morton (Department: 1711)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S423000, C029S424000, C029S897320, C521S138000, C521S182000
Reexamination Certificate
active
06766571
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an adhesive for use in sealing together two surfaces, for use especially in the glazing industry in general and in securing vehicle windscreens and/or windows. The invention also provides a method of use for installing and/or replacing vehicle windscreens and/or other fixed glazing on vehicles.
BACKGROUND OF THE INVENTION
Typically to install a window pane in a wooden/plastic/metal frame, the glass pane is firstly held in position against nails or other clasps and then fixed into position by putty or plasters material. Conventional putty is a cement made from whiting and linseed oil which hardens over time to provide a peripheral rim of the window pane, thus separating interior and exterior environments and preventing air, moisture and/or heat transfer. The installation is completed once the putty has dried and this usually takes up to 6 hours or so depending on the kind of plasters used.
To remove a window pane after it has been fixed in position in a frame requires the window itself to be shattered so that the hardened putty or plasters can be scraped/chiselled away from the frame. The removal operation can cause damage to the frame and varnishes.
In use, the window pane is held rigidly around its edges so that even relatively small vibrational mechanical movements such as with earthquakes or bomb blasts or strong winds can cause the window pane to shatter.
In the automotive industry, cars direct from the factory production line typically have the windscreens and other fixed windows, including light assemblies fixed into position by placing the glass against a frame rim and using adhesives so as to direct glaze the glass. The life span of a windscreen and other fixed windows are significantly shorter than that of the vehicle itself partially due to degradation or damage or being deliberately broken by vandals/car thieves. Thus a motorist may need to replace the windscreen several times during the vehicle's lifetime.
Additionally, glued glazings have to be replaced any time the window, especially the windscreen, has been damaged in its optical performance by, for example, impact stones or other fractures or abrasion by wipers. Damage to the window surface can increase the scattering of light and may reduce the visibility to levels below safety limits. Moreover, regulations of motor worthiness stipulate that there can be no chips or visual impairments on laminated windscreens, so whereas recent improvements have made the windscreens shatter-proof, they are still prone to chipping and fracturing and thus will require replacement.
The process of replacing vehicle windscreens is both laborious and time consuming. The automotive glass fitter has first to remove the defective windscreen (usually in intact form), however the windscreen is firmly bonded in place and the adhesive sealant is hardened. Typically the fitter uses a device comprising a cheesewire. The cheesewire is used to cut/saw through the hardened rubber along the periphery of the windscreen. This process requires physical force and can lead to musculo-skeletal conditions in the fitters themselves as a result of repetitive strain injury. Further problems associated with this method are that the cheesewires can overheat due to friction, additionally the wires themselves can break and consequently injure the fitter's limbs/hands/eyes.
Other methods of detaching the windscreen from the adhesive sealant include: the use of mechanical oscillator knives/cutters to cut through the hardened material or; directed heat such as a laser beam to soften the sealant prior to removing the windscreen with either cheesewire or specialised bladed tools. The problem with a method where heat is directly applied to the sealant is that the heat required to soften the hardened adhesive sealant can concomitantly and inadvertently damage the vehicle's paintwork and/or other exterior surfaces. For example, a pulsed laser that is set to pulse too fast will not generate enough energy to char the adhesive sealant and a pulsed laser that is set too slow will burn the adhesive sealant and liquify it.
Once the windscreen has been freed from the rubber sealant it can be removed and the surround scraped before it is replaced. It is known from the prior art to use urethane based adhesives to fix/seal the replaced windscreen in place and to apply the adhesive from a dispenser gun to specific peripheral edges so as not to impinge on the viewing capacity of the windscreen. The adhesive typically takes about 8 hours to cure.
Recent advances to the industry have provided for the inclusion of fast cure agents/catalysts so as to speed up the time from vehicle drop-off to vehicle collection. The fast cure agents/catalysts can be provided pre-mixed in the adhesive composition or alternatively can be mixed with the adhesive at the point of exit from a dispensing gun. However the problem still remains that the removal of a defective windscreen and its subsequent replacement is a laborious and time consuming process which can result in damage to the dashboard interior or vehicle paint-work.
A further disadvantage associated with present adhesives such as polyurethanes and/or MS polymers and/or other adhesives is that before applying the adhesive around a window aperture, the aperture surface and glazing must be rigorously cleaned/degreased and primed. This process can be time consuming moreover the fitter can be exposed to liquid and/or volatile organic chemicals and associated health risks. In addition, polyurethane adhesives typically also comprise small amounts of isocyanates. Both polyurethanes and isocyanates are considered to be environmentally unfriendly. Disposal of car components, such as present windscreen glazing rims/rebates, at the end of the vehicle's life can cause ecological damage.
An adhesive that could satisfy vehicle safety crush and crash standards and provide for easy, rapid, effective and damage-proof removal of a defective windscreen or other fixed glazing from a vehicle would offer immediate improvement to the industry and consumer. Additionally an adhesive that could be reused and be more envirornmentally safe than present adhesives would also be of great benefit.
In a completely different technical field it is known to provide polyesters containing air bubbles. These polyester sponges have inherent tackiness and anti-static properties and, in slab form, they have found use as anti-upset mats. In use, the mat is placed on a solid surface, for example, a desk, and the mat adheres by virtue of its tackiness to the desk surface. Office equipment or cups or other articles can be placed on top the mat. The lower surface of the article to be anchored, i.e. that in contact with the upper surface of the mat, adheres to the mat. Thus, the article remains fixed in position on the double-sided tacky mat and the fixed article is able to withstand shock, slide and earthquake motions. The mats are reusable in that they may be peeled off a surface and re-positioned/re-stuck to another surface. In the instance that the mat loses some of its tackiness, it can simply be washed with water to remove any dust and the tackiness is restored.
SUMMARY OF THE INVENTION
We have found that, by adapting the bubble size pattern, shape and overall bubble content of the polyester sponge and developing the material into a ribbon form, such a composition is surprisingly effective as a glazing adhesive. Moreover, the composition of the present invention overcomes many of the problems associated with prior art glazing adhesives.
We believe that the invention provides the first application/use of a polyester material in the automotive glazing industry.
It will be appreciated that the adhesive of the invention has application in other areas especially where two surfaces are to be bonded together and where one surface may subsequently need replacing following damage or wear, for example and without limitation, shower doors, picture framing, green houses and constructional double glazing.
REFERENCES:
p
Bain Peter Stewart
Manfre Giovanni
Foelak Morton
Myers Bigel Sibley & Sajovec P.A.
LandOfFree
Adhesive composition comprising thermoplastic polyester and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Adhesive composition comprising thermoplastic polyester and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adhesive composition comprising thermoplastic polyester and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3208467