Volume 3, Issue 10 (November 2006)
New Durable Sealant of Telechelic Polyacrylate
In this paper, we discuss the application possibilities of a novel telechelic acrylic polymer (NTP) which we have been developing as a versatile base polymer for sealants and adhesives. Due to its unique features, our NTP is expected to offer a variety of applications, including the one for sealants applied in contact with self-cleaning glass (SCG). Our discussion here focuses on the possibilities of this particular application. SCG possesses a photocatalyst layer which enables two reactions, i.e., lessening the contact angle of the glass surface and decomposing organic compounds on the glass surface, by reacting with sunlight. The reactions help wash off dust from the glass surface, mainly by rainwater, to maintain the clearness and beauty of the glass used for building windows in particular. Conventional sealants for this application often lack sufficient weatherability or risk, or a combination thereof contaminating the glass surface causing hydrophobicity. The NTP sealants, on the other hand, has no surface-polluting substances such as a low-molecular-weight silicone often contained in silicone sealants, while maintaining high weatherability. We have conducted our research to study the weatherability of the NTP sealants on SCG and the possible contamination of the SCG surface by the sealants. Our studies have found that the NTP sealants retain good adhesiveness after more than 10 000 h of exposure to UV irradiation (in a Super Xenon Weather Meter) at the interface between the sealant and the glass. We also have found almost no contamination on the SCG surface by the NTP sealants, demonstrated by the results of our tests conducted to measure the contact angles of sealant samples to the glass, through outdoor exposure for about two months.