二. Bottle Manufacture 3. Surface Coatings ⚫ Purpose-to reduce the coefficient of friction ⚫ Reasons-The inner and outer surfaces have different characteristics The outer surface comes in contact with the mold and takes the grain of the mold surface Both surfaces are pristine: monolithic, sterile, and chemically inert. Pristine glass has a comparatively high coefficient of friction Surface scratching has lower breakage resistance ⚫ Methods- hot-end coating ; cold-end coatings The hot-end coating applied at the entrance to the annealing lehr to strength the glass surface Cold-end coatings depending on the filling process and end use. Typical cold-end coatings-oleic acid, monostearates, waxes, silicones, polyethylenes ⚫ The label adhesive as one cold-end coating.二. Bottle Manufacture 3. Surface Coatings ⚫ Purpose-to reduce the coefficient of friction ⚫ Reasons-The inner and outer surfaces have different characteristics The outer surface comes in contact with the mold and takes the grain of the mold surface Both surfaces are pristine: monolithic, sterile, and chemically inert. Pristine glass has a comparatively high coefficient of friction Surface scratching has lower breakage resistance ⚫ Methods- hot-end coating ; cold-end coatings The hot-end coating applied at the entrance to the annealing lehr to strength the glass surface Cold-end coatings depending on the filling process and end use. Typical cold-end coatings-oleic acid, monostearates, waxes, silicones, polyethylenes ⚫ The label adhesive as one cold-end coating