Influence of silicone fillers on silicone pressure-sensitive adhesives properties

Pressure-sensitive adhesives (PSAs) represent a system that actually dates back to the invention of the self-adhesive articles in 1935 when R. Stanton Avery produced the first coating unit using a wooden cigar box with two holes cut in the bottom. PSAs can be defined as a special category of adhesive which in dry form are permanently tacky at room temperature [2, 6–8]. Since 1960s, silicone pressure-sensitive adhesives have found many uses. They are used in industrial plants, as tapes for joining materials with low surface energy, as well as in the sectors of electrical and electronic, medical care, health care and automotive industry. For about 10 years there has been great interest in new uses for the silicone PSA, particularly for medical and industrial belts. The above examples describe a growing range of potential commercial applications of silicone pressure-sensitive adhesives [2, 7, 9–11]. In contrast to the pressure-sensitive adhesives organic silicone pressure-sensitive adhesives show much better performance by this well known it happened that are used to obtain self-adhesive materials for special purposes. Si-PSA usually consist of large segments of the silanol-functional silicone polymers, and silicone resins. Polymeric chains comprising the silicone resins include methyl and phenyl groups thus are very little reactive chemicals. In order to obtain the best adhesion-cohesion balance are used crosslinked thermally in a temperature range of 120–150°C by using organic peroxides. Peroxides most commonly used in industry benzoyl peroxide (BPO) and 2,4-dichlorobenzoyl peroxide (DClBPO). Silicone pressure- -sensitive adhesives are characterized by high flexibility of connections Si-O-Si, low impact intermolecular, low surface tension, excellent thermal stability and transparency for UV radiation, excellent electrical properties, high chemical resistance and weather resistance [2, 6, 7, 14]. In the available literature the montmorillonite and kaolin modified silicone pressure-sensitive adhesives which exhibited increased thermal resistance are reported. The thermal properties of adhesives compositions are better to compared with “pure” silicon composition without any filler [6, 12–14]