| 摘要 |
1511839 Modification and cure of unsaturated polysiloxanes with 1,3-dipolar compounds IMPERIAL CHEMICAL INDUSTRIES Ltd 16 Oct 1975 [25 Oct 1974] 46253/74 Heading C3T Siloxanes containing at least one non- terminal Si atom bearing aliphatic carboncarbon unsaturation are modified by reaction with a compound A(BDz)y wherein A is H, or an organic group containing C and H and optionally O atoms, or an organometallic, organosilicon or polymeric group, or may be a direct bond when y is 2, B is a 1, 3 dipolar group, D is H or a monovalent organic group, z is 0-4 and y, the valency of A, is 1 to 10. Suitable groups B include: nitrile oxide nitrile sulphide nitrile imine nitrone diazoalkane sydnone and isosydnone the compounds may be prepared in situ if necessary. In Examples (i) polydimethylsiloxanes containing MeViSiO units and optionally MePhSiO units, which may be used, in heptane solution, to coat paper, are cured to rubbers using 10 p.h.r. of terephthaldinitrile oxide, ONC-C6H4-CNO, or smaller quantities when a silica filler is present; (ii) similar siloxanes or one containing propargyloxy or acrylatopropoxy groups are gelled by reaction with 5-10 p.h.r. of terephthaldinitrile oxide, benzene 1,4- bis(phenyl nitrone) or p-phenylene-3,3-bis-sydnone; a nitrile imine, used to gel a siloxane, is generated in situ from terephthaloyl - bis - phenylhydrazide and Et3N, and a nitrile sulphide, used to cross-link a rubber stock, is generated in situ from ethylenebis - 1,3,4 - oxathiazol - 5 - yl - 2 - one; (iii) pyrazoline groups are introduced into an acrylatopropoxy siloxane by treatment with ethyl diazoacetate. The process of Specification 1,474,691, wherein a dinitrile oxide is generated in situ from a polycyclic furoxan, is disclaimed. |
