Tire Mold Coatings
Tire mold coatings are applied to the surface of tire molds to help minimize mold fouling, aid rubber flow, assist in the release of the tire from the mold at the end of the cure cycle† and to enhance finished tire appearance. When applied using our recommended technique they will keep tire molds in service longer between cleanings.
Chem-Trend supplies the tire industry with two families of semi-permanent mold treatments. The primary type is a wide selection of water-based treatments that are intended for application to a hot mold surface. The secondary type is solvent-based mold conditioners and protectors that are applied to the surface of newly cleaned molds when they are out of the curing press.
Water-based mold treatments coatings are applied to tire molds when they are installed in the curing press and at operating temperature. Two to three light coats are applied to the surface of the mold, particularly the sidewall plates, by spray application. The water flashes off almost instantaneously and the coating cures to bond to the surface of the mold to provide a semi-permanent layer that effectively “seals” the surface of the mold. The resulting smooth surface reduces friction for the rubber flowing over it, which leads to sharper sidewall lettering and cleaner edges to tread blocks and channels, therefore greatly improving finished tire appearance. The coating also improves the release of tires that are notoriously difficult to de-mold, e.g. winter tires with sticky tread compounds and complicated tread patterns. The coating formed on the mold also delays the onset of mold fouling, thus keeping molds in service for longer between cleanings. Increasing the period between cleanings not only reduces downtime, and total mold cleaning costs, it also helps to prolong overall mold life.
These coatings are semi-permanent, which means they release several tires between applications. Regular refreshment ensures optimum performance – the actual frequency of refreshment depends in large part on the type of tires being molded, cure time and mold type (e.g. two-piece or segmented).
The excellent release properties seen from molds that have been treated with a water-based mold coating from Chem-Trend can be particularly helpful when using two-piece tire molds. Those tire manufacturers using two-piece molds will know that it is not unusual to experience difficulties in extracting cured tires from the top half of these molds; this creates downtime and can cause damage to the finished tire. Regular application of a Chem-Trend water-based mold treatment to the top-half of the mold helps keep the tire in the bottom half of the mold when the press opens by ensuring easy release from the top half. This technique helps reduce tire defect levels and down-time associated with extracting tires that are difficult to remove.
Solvent-based mold treatments are specifically designed for application to the cool surfaces of molds that have been removed from the curing press for maintenance and/or cleaning. A solvent-based material is necessary in these unique circumstances to ensure good wetting† of the cool surface and to avoid flash corrosion of the freshly cleaned metal surface. Once applied, typically with the use of hand-held spray guns, the solvent quickly evaporates leaving a coating across the surface of the mold that seals it against corrosion. The film also offers protection against corrosion to molds that are stored for prolonged periods – up to one year. It is not unusual to see mineral oils, or similar products, used to protect molds stored for periods of greater than a few days; these protect the mold during the storage period but require cleaning from the mold surface prior using the mold in service again. Solvent-based mold treatments from Chem-Trend do not require cleaning from treated molds prior to being placed back into service, which makes them attractive to those looking to maximize efficiency.
To learn more about the solutions that Chem-Trend has innovated to improve the efficiency of tire production around the world visit the appropriate pages below, or contact us directly to see how we can help you.