Patent GB-1070658-A (GB)
Title: Organo-silicon elastomers
IPC: C08L83/04
Filed: 1964-11-02
Abstract: A vulcanization agent for an organosiloxane polymer comprises (a) a compound containing at least 3 silicon bonded OR1 groups per molecule where R1 is a monovalent hydrocarbon, radical halocarbon radical or ether residue and (b) diethanolamine; (a) may be a silane of formula RmSi(OR1)4- m in which R is a monovalent hydrocarbon, halohydrocarbon or cyanohydrocarbon radical and m = 0 or 1, a liquid partial hydrolysate of such a silane or a finely-divided silica which has been esterified with an alcohol, R1OH.  Many R and R1 groups are specified.  They may be linear or branched and may contain up to 19 carbon atoms. Silanes specified include methyl trimethoxysilane, ethyl triethoxysilane, methyl triethoxysilane, diethoxydimethoxysilane, tetraethoxysilane, tetramethoxysilane, vinyltri-n-butoxysilane, tetramethoxyethoxysilane, and phenyl-tri-(ethoxyethoxy) silane. These may be hydrolysed, converting 1-2 of the OR1 group to OH which condense to give polysiloxanes. The polymer should contain at least 0.5 R1 groups per Si atom and no more than 10 Si atoms.  They may comprise units of formula <FORM:1070658/C3/1> where n = 1, 2 or 3 and m+n is 3 or less. Hydrolysates specified include: hexaethoxydisiloxane. Silica of 1-900 sq. m. per gram surface area can be esterified by heating it with alcohol at at least 100 DEG  C. in the presence of a strong acid or base.  The butyl and ethyl esters are specified.  Reactants (a) and (b) may be present in a ratio between 1:1 and 1:100, 0.5-15 parts by weight of (a), being present per 100 of polyorganosiloxane; (a) and (b) may be reacted at between room temperature and 200 DEG  C.  The organosiloxane polymer may be of at least 25 cs. viscosity at 25 DEG C. and comprise R2SiO repeating units and OH and groups optionally together with less than 2 mole per cent of RSiO 3/2 , R3SiO 1/2 , SiO 4/2 , and (HO)2R SiO 1/2  units in such quantities that the R/Si ratio is between 1.99 and 2.01 and the HO/Si ratio in the end groups is between 0.99 and 1.01.  It may also contain silcarbane links. Polymers specified include poly-(dimethylsiloxane) having terminal OH groups, (HO)2C6H5 SiO[CH3(CF3CH2CH2)SiO]100 Si(CH3)2OH; HO (CH3) (CH2=CH) SiO [CH3 (C6H5) SiO]10[CH3)2 SiO]90SiCH3C6H5OH, and HO(CH3)(CF3CH2 CH2) SiO[CH3(C2H5)SiO]50 Si(C6H5) (CH=CH2) OH.  The vulcanizing agent may be added to the siloxane prior to moulding. Plasticizers, solvents, pigments, solulble dyes, perfumes, oxidation inhibitors, heat stabilizers, flame inhibitors, light stabilizers, trimethyl siloxane endblocked dimethyl siloxane and 5-200 parts by weight of filler per part by weight of polymer may be added.  Many fillers are specified, including quartz flower, zirconium silicate and diatomaceous earth.  Vulcanization may occur at room temperature or elevated temperature. The products may be used in building, and aeroplane and car production for protective coatings, electrical and thermal insulation, encapsulating electronic installations, taking impressions, finishing textiles, and preparing sheets, moulds and laminates.ALSO:Glass and metal surfaces may be coated with organosiloxane elastomers prepared by mixing (1) a hydroxy-ended organo-siloxane polymer with (2) the reaction product of (a) a compound containing at least 3 silicon bonded -OR1 groups where R1 is a hydrocarbon or halohydrocarbon group or a group containing carbon, hydrogen and ether oxygen and (b) diethanolamine.  In Example (2) a reaction product of diethanolamine and ethyl polysilicate is mixed with a hydroxy-ended poly (dimethylsiloxane) containing quartz flour; the mixture is applied to steel and glass and allowed to harden.  In Example 3 the quartz-flour is replaced by zirconium silicate and the mixture applied to glass, steel, aluminium, copper, brass and zinc-coated iron.