| 摘要 |
The present invention relates to a silicone composition cross-linkable into elastomer, and to a method which uses the composition of the invention to form joints for sealing and assembling the components of a power train. The silicone elastomers prepared from the composition according to the invention have the following properties: good resistance to aging in chemically aggressive fluids, such as those used for example in a power train, in this case motor oils, gearbox and axle lubricants, oil/gasoline mixtures, coolants, and fuels or antifreeze liquids; good adhesive properties including on surfaces soiled with oils used in power trains; and good mechanical strength properties, such as tensile strength, modulus at 100% elongation, and Shore hardness. |
| 主权项 |
1. A process for sealing and assembly of at least one component of a power train, comprising the following a) to d):
a) preparing a polyorganosiloxane composition X, b) applying said polyorganosiloxane composition X to at least one contact region of said component, continuously or noncontinuously and optionally in a form of a strip, c) allowing said polyorganosiloxane composition X to crosslink to form a silicone elastomer in the presence of moisture contributed by ambient air or by prior addition of water, so as to form a gasket, and d) assembling said component with another component of the power train so that a seal formed provides for assembly and sealing between two components of the power train,
wherein X comprises:A) at least one polyorganosiloxane A comprising at least one alkoxylated group and comprising identical or different siloxyl units, of formula:
(Z)b(R4)aSiO[4-(a+b)]/2 (1)in which:
the symbol Z=[—(OCH2CH2)c-OR5], with c=0 or 1,a=0, 1, 2 or 3; b=0, 1, 2 or 3, a+b=0, 1, 2 or 3,the symbol R4 represents a monovalent C1 to C13 hydrocarbon radical,the symbol R5 represents a monovalent C1 to C6 hydrocarbon radical or an alkoxyalkyl radical optionally comprising an ester functional group, andwith the condition that, for at least one siloxyl unit, the index b≧1, so that the polyorganosiloxane A comprises at least one alkoxylated group Z,B) at least one siloxane D which is a condensate obtained by partial hydrolysis and condensation of a polyalkoxylated silane, said siloxane D having from 2 to 10 identical or different siloxyl units, of formula:
(R2)x′(OR3)y′SiO[4-(x′+y′)]/2 (2)in which:
x′=0, 1, 2 or 3; y′=0, 1, 2 or 3; x′+y′=0, 1, 2 or 3,the symbol R2 represents a monovalent C1 to C13 hydrocarbon radical,the symbol R3 represents a monovalent C1 to C6 hydrocarbon radical or an alkoxyalkyl radical optionally comprising an ester functional group, andwith the condition that, for at least one siloxyl unit, the index y′≧1,C) an additive E capable of absorbing an oil used in a power train comprising acetylene black,D) a catalytically effective amount of at least one condensation catalyst F,E) optionally at least one filler G,F) optionally at least one adhesion promoter H, andG) optionally at least one additive I, optionally comprising a coloring base, a pigment or a thixotropic agent. |
