FACTS YOU SHOULD KNOW ABOUT WINDSHIELD REPAIR RESINS

Understanding the science behind a windshield break and crack; how a windshield is made and the resins created to fix windshields are important for anyone in the windshield repair industry to know.

This deep understanding of windshield repair chemistry will help you buy better resin and relay to your customer that you are the expert they should trust to repair their safety device. See Lab Test Results and Scores on 12 Windshield Repair Resins here.

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An  adhesive is a substance that bonds surfaces together. Resin in polymer chemistry is a liquid substance that is convertible into polymers. A polymer is a large molecule and/or many monomers.

A monomer is a small molecule that is able to bond into long chains to identical or different molecules to form a polymer. Resins are a mixtures of monomers and polymers that can be organic or synthetic compounds. The linking up of monomers is called polymerization.

High Energy Surfaces versus Low Energy Surfaces - High energy surfaces are strong solid hard surfaces where the bonds that hold them together are very strong such as glass, ceramic and metal. These high strength chemical bonds are called covalent, ionic or metallic. Low energy surfaces are soft, deform or bend easily such as PVB and plastics. Liquid adhesives are also low energy, they can wet and bond easier to high energy surfaces than they do to low energy surfaces. Two low energy surfaces do not bond well.

Surface Tension is present with windshield repair because there are two substrates. (1) The glass which is high energy and (2) the PVB which is low energy. The resin (low energy) is more attracted to the glass than it is to the PVB. Resin wets the glass but not the PVB. Meaning the bond is an inter-molecular chemical bond to the glass but a mechanical bond to the PVB. This tension will cause the resin to pull back and off of the PVB upon curing when the resin begins to shrink as it cross-links to itself and the glass. This can happen and be seen upon or after curing. This will show up as a bubble or void with a stone break and with a crack repair a long thin separation along the PVB called a "runner".

The method used by most with a stone-break repair to cure this deficiency is to cure with the injector in the pressure mode (cure under pressure) to create an overfill in the void, which compensates for shrinkage and forces a bond onto the PVB. With a crack repair which is surfaced the resin cannot shrink more than 1-2% and must be mechanical enough to stay put upon curing which is the case with  Ultra Bond Crack Repair Resins. The cure of shrinkage and surface tension in cracks was patented by Richard Campfield and is the multi-viscosity Ultra Bond method with the Ultra Bond custom crack resins.

If the surface tension is not dealt with by the repair system/process the resin can separate from the PVB down the road from temperature change and bring back a void between the resin and the PVB even if it is not visible after curing. This void will refract and the repair will no longer pass the  ROLAGS.

UV Cure Speed Slow curing (2-5 minutes) controls shrinkage and residual stress. Curing too fast causes more shrinkage and more stress leading to breaks in the polymer chain, stressed cross-links and stranded molecules. The good news about this is you do not need expensive high-speed curing lights. Ultra Bond uses photo initiators that cure with Sunlight and inexpensive low watt 365 nm fluorescent curing lights which produce a better end product. LED curing lights do not give an even intensity of UV energy. They have very high standard deviation and can destroy the cured resin structure.

Here are The Strongest

Windshield Repair Resins in the WORLD