Cured silicone products having a wide range of properties useful in a wide range of applications are well known, as is the formation of those products by curing organopolysiloxanes by crosslinking individual organopolysiloxanes or mixtures of various organopolysiloxanes. One particular family of organopolysiloxanes which are useful in forming adhesives and other materials are those diorganopolysiloxanes which are terminated at either or both ends of the chain with vinyl groups. Examples of such vinyl terminated polysiloxanes appear in U.S. Pat. No. 4,196,273 to Imai et al. Vinyl terminated polysiloxanes may be crosslinked with themselves or with other polysiloxanes containing various functional groups which are aryl, aliphatic (saturated or unsaturated), fluoroaliphatic (such as CF.sub.3 CH.sub.2 CH.sub.2 --) or containing other groups such as nitrogen groups, sulphur groups and the like. Examples of such organopolysiloxanes are shown in U.S. Pat. Nos. 3,624,022 to Ross, 4,064,027 to Gant, and 4,163,081 to Schultz.
Diorganopolysiloxanes terminated at the chain ends with two or three vinyl groups have been crosslinked to provide elastomeric or rubber-type products, as shown in U.S. Pat. No. 4,364,809 to Sato et al.
The disclosures of the above patents are incorporated herein by reference with respect to the conventional and general background relative to the types of organopolysiloxane materials which may be crosslinked, the methods of crosslinking polysiloxanes, the initiators used to initiate the crosslinking and other conventional aspects of the organopolysiloxane art.
In many end use applications it is desirable to use organopolysiloxane materials are sealants and as such the materials should preferably have a cone penetration of about 100 to about 350 (10.sup.-1 mm) (ASTM No. D217-68) and an ultimate elongation of at least about 100% (ASTM No. D638-80). In many uses it is desirable to have elongation values as high as 800% or greater because of the extreme deformation the material must be capable of accommodating in order to effectively sal some substrates. it is also desirable to make such sealing materials from the most widely available and consequently lowest cost polysiloxanes, such as polydimethylsiloxanes, trimethylsiloxy terminated.