| abstract |
This invention relates to solventless, curable polyorganosiloxane compositions, and in particular, to solventless, curable polyorganosiloxane compositions that can be used to prepare release coatings. Solventless silicone compositions generally provide release surfaces that exhibit a sticky or rubbery feel, which is disliked by users of certain types of transfer tapes. Users of large transfer tapes, e.g., tapes consisting of a layer of a pressure-sensitive adhesive borne on a removable silicone release liner, prefer to place the tape on the desired substrate, then press the tape down firmly with their hand or forearm, remove the silicone release liner, and then press the second substrate in contact with the exposed surface of the tape. The users desire that the release liner exhibit a slippery feel so that the friction between the liner and their hand or forearm not bring about chafing of the skin. This invention provides curable, solventless, liquid polyorganosiloxane compositions for providing release coatings that exhibit a slippery feel. The composition comprises (a) a first polydiorganosiloxane terminated by silyl groups having one reactive group; (b) a second polydiorganosiloxane terminated by silyl groups having one reactive group, the reactive group of (a) being the same or different from the reactive group of (b), said reactive groups of (a) and (b) being reactive with one another to form a covalent bond; (c) a polydiorganosiloxane having three or more reactive groups that are reactive with either the reactive group of (a) or the reactive group of (b) or both to form a covalent bond; and (d) a catalyst for effecting the reaction of the reactive groups of (a), (b), and (c) to form covalent bonds. When coated on a substrate and cured, the composition provides release liners for pressure-sensitive adhesive tapes and pressure-sensitive adhesive transfer tapes. |