Adhesive-Sealer, Silicone Rubber, One Part RTV
|Publication Date:||1 August 2019|
This specification details the requirements and properties of Room Temperature Vulcanizing (RTV) silicone rubber compositions that are suitable for use as supplied as an adhesive or sealer. Uses include polycarbonate lens to reflectors (e.g., in composite headlamps), acrylic or polycarbonate lenses to reflectors in exterior signal lighting, attachment of fiber optics to reflectors, etc.
Typical uses for RTVs are bonding second surface acrylic, adhering cast urethane decorative inserts into mating bezels, assembling decorative trim, sealing electronic module covers to housings, both interior and exterior and for bonding coated polycarbonate headlamp lenses to housings.
Catalyst, heat, or pressure is not needed to initiate vulcanization. Once applied, the material begins to react with atmospheric moisture and immediately begins curing to a rubber like product.
Adhesion of the material is excellent to most plastics. In some extreme cases, a primer or surface treatment may be required to provide maximum performance.
Most RTVs are compatible with most plastics, however, new applications should reconfirm that the new substrate is not crazed, cracked or otherwise degraded by the RTV.
The cure mechanism is a non-acidic, or neutral cure. By-products of the curing process shall not corrode, stain, or otherwise adversely affect decorated second surface acrylic or other plastic inserts.
Mixing of various RTV materials in the same pumping system could cause cure inhibition. This can be resolved by purging the pumping system with the new material and then monitoring the appearance, color, odor and tack time to ensure uniformity of the adhesive.