| 摘要 |
<p>Prepn. in situ of reinforced silicone elastomer comprises: (A) forming a mixt of a diorganosiloxane polymer of formula (I) Q3-aRaSi(OSiR2)xOSiRaQ3-a a stoichiometric excess of a reactive siloxane selected from triorganosilyl endblocked reactive siloxanes of formula (II) R3Si(OSiQR)2OSiR3 and reactive cyclosiloxanes of formula (III) (OSiQR)y and a tin salt catalyst; and (B) contacting the mixt with water to effect curing of the mixt to form an in situ reinforced silicone elastomer, each R= independently selected from 1-6C alkyl, 2-6C alkenyls and aryls; each Q= hydroxy, acyloxy, oximos of formula -ON=CR1c, where each R is independently selected from 1-12C alkyl, 1-6C alkoxy opt. substd.; a= 0-2; x= 0-1000; z= 3-500; and y= 3-10. Also claimed is the in situ reinforced silicone elastomer prepd as above. Pref. each R is methyl and each Q of (I) is hydroxy, and a= 2, each Q of (II) is 1-6C alkoxy, pref methoxy. z= 10-100. y is 4-6. The amt of Q provided by (II) is 5-10 times stoichiometric excess in relation to the substit Q provided by (I). The tin salt catalyst is dibutyltin dilaurate, dibutyltin dibenzoate, dibutyltin diacetate or stannous (II) ethyl hexanoate. The conc of the catalyst being 0.005-10 (0.01-2) wt% of the combined wt of the catalyst, (I) and (II). Curing the mixt is effected in a moist environment having 30-70% RH. The process is conducted at 20-30[deg] C.</p> |
