Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Patent
1994-07-29
1995-12-12
Marquis, Melvyn I.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
528 15, 528 18, 528 21, 528 23, 528 31, 556487, 556482, 523209, 523212, 524731, 524791, 524789, 524779, 524730, 524860, 524786, 524785, C08G 7706
Patent
active
054750768
DESCRIPTION:
BRIEF SUMMARY
The invention relates to organo(poly)siloxane compositions which have a long shelf life in the absence of water, but can be crosslinked in the presence of water, even at room temperature, to give elastomers with elimination of alcohols, and to a process for the preparation of such compositions.
Organopolysiloxane compositions which can he crosslinked to give elastomers with elimination of alcohols and processes for their preparation are known in large number. Reference may be made here, for example, to U.S. Pat. No. 3,334,067 (Dow Corning Corp.; published on 1 Aug. 1967), in which a process is described for the preparation of room temperature-crosslinkable organopolysiloxane compositions by mixing a hydroxyl-containing organopolysiloxane with an organyl(triorganyloxy)silane and a titanium compound. Furthermore, DE-A 3 801 389 (Wacker-Chemie GmbH; published on 27 Jul. 1989) and the corresponding US application having the serial number U.S. Ser. No. 29 3909 (filed on the 6th Jan. 1989) describe organopolysiloxane compositions which can be crosslinked to give elastomers with elimination of alcohols and have been stabilised by sails from main group or subgroup 2 with branched carboxylic acids. Furthermore, U.S. Pat. No. 3,708,467 (General Electric Co.; published on 2 Jan. 1973) describes a curable composition which is obtained by mixing an organopolysiloxane containing hydroxyl groups in the terminal units with methyltrimethoxysilane and a cocatalyst system.
However, such compositions generally have a very slow crosslinking rate, and metal compounds, such as, for example, tin compounds, must therefore be added as a condensation catalyst in order to accelerate the reaction. However, this frequently impairs the shelf life, so that such compositions only cure very slowly, if at all, after relatively long storage.
DE 39 39 176 A1 describes organosilicon compounds which do not contain an SiC bond and which comprise H(R.sup.1 O)SiO.sub.2/2 and H(R.sup.1 O).sub.2 SiO.sub.1/2 units, where R.sup.1 is a hydrocarbon radical.
FR 1125886 describes organopolysiloxanes which contain a hydrogen atom on each silicon atom and alkoxy groups on the terminal silicon atoms.
EP 22 976 describes polysiloxane molding compositions which comprise hydroxy-functional siloxane, crosslinking agent, filler, optionally a curing catalyst and a silicon compound containing at least 3 alkoxy groups, such as, for example, tetraethoxysilane.
The object of the present invention was to provide organo(poly)siloxane compositions which can he crosslinked to give elastomers with elimination of alcohols and can be stored for a long time in the absence of water without any significant change in their desired properties and crosslink in a relatively short time in the presence of water to give elastomers. A further object of the present invention was to provide a process for the preparation of organo(poly)siloxane compositions which can be crosslinked to give elastomers with elimination of alcohols. These objects are achieved by the present invention.
The invention relates to organo(poly)siloxane compositions which can be crosslinked to give elastomers with elimination of alcohols and can be prepared from ##STR1## and/or partial hydrolysates thereof and/or partial condensates thereof and/or partial cohydrolysates thereof with (C) and/or partial cocondensates thereof with (C) and/or the products of the reaction of these hydrolysates and condensates with R.sup.2.sub.3 SiOH and/or R.sup.2.sub.3 SiOSiR.sup.2.sub.3, with the proviso that each organosilicon compound molecule contains on average more than two organyloxy radicals RO-- or R.sup.4 O-- where R and R.sup.4 are monovalent, optionally substituted hydrocarbon radicals, where hydrocarbon radical or the radical --SiR.sup.2.sub.3, organic radical or an organosiloxy group, monovalent organic radical, substituted organic radical, 1 and 1,000, 1 and 100, 1 and 100, 1 and 100, and ##STR2## and/or partial hydrolysates thereof and/or partial condensates thereof and/or the products of the reaction of these hydrolysa
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Absmaier Petra
Braun Rudolf
Connaughton Martin
Marquis Melvyn I.
Wacker-Chemie GmbH
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