Patent GB-621742-A (GB)
Title: Improvements in or relating to condensation-polymerisation products of silicon ortho-esters
IPC: C08G77/00
Filed: 1946-02-02
Abstract: Silicon ortho-esters which have been hydrolysed by less than one mol. of water per mol. of ester are refluxed for more than 2 hours, products boiling at or below the boiling point of the ester being removed (a) simultaneously with, or (b) on completion of the refluxing.  The esters employed may be alkyl, aryl or aralkyl esters, preferably alkyl esters containing 2 to 6 carbon atoms in the alkyl group and may be prepared from alcohols containing about 5 per cent water (e.g. industrial methylated spirit).  Specified partly hydrolysed esters are English neat ester and partly hydrolysed butyl, hexyl and cresyl ortho-silicates.  Process (a) leads to resins suitable for use in coating or moulding compositions, e.g. for electrical insulation and in laminated products.  Process (b) leads to oils suitable for power transmission, e.g. brake fluids, transformer oils or lubricants. The oily products of process (b) may be heated under pressure with cellulosic materials, e.g. wood-flour, cotton-wool or sulphite paper, with or without the addition of a polymerization accelerator, e.g. hydrogen chloride or piperidine.  In examples: (1) English neat ester was refluxed for 30 hours under a column so adjusted that substances boiling above 165 DEG  C. were retained and the residue was heated in the open for 1 hour at 260 DEG C. to produce a rubbery resin; a 1 per cent solution of this resin in benzene was used to coat copper foil or glass, to laminate two pieces of glass, and to waterproof filter paper or a porous refractory insulator; (2) English neat ester was refluxed for 70 hours with the column head at 50 DEG  C., and then heated above 220 DEG  C. until the steel head was at 110 DEG  C., to obtain an oily product: (3) English neat ester was refluxed for 36 hours and then distilled under atmospheric pressure to remove products boiling up to about 165 DEG C.; an oil was obtained: (4) butyl alcohol containing 3.9 per cent of water was reacted with silicon tetrachloride and hydrochloric acid and alcohol removed by blowing with dry nitrogen at 70 DEG  C; the product was refluxed for 30 hours and then distilled to obtain an oily product boiling from 220 DEG  to 365 DEG  C.: (5) industrial hexyl alcohol was reacted with silicon tetrachloride and the product heated at 60 DEG  C. for 4 hours and at 100 DEG  C. for 6 hours and then boiled on a sand tray for 6 hours to remove low boiling constituents: (6) o-cresol containing a small quantity of water was reacted with silicon tetrachloride and the temperature was raised to 220 DEG  C., the heating continued under total reflux for 8 hours to obtain an oil: (7), (8), (9) the product of example 1, used as such or with the addition of hydrogen chloride or piperidine, was mixed with wood-flour, preformed, and moulded under heat and pressure: (10) a product prepared as in example 1, but from n-butyl silicate, is mixed with piperidine and wood-flour and moulded: (11) the product of example 1, piperidine, and cotton-wool, are preformed, then moulded under heat and pressure: (12) a paste of the product of example 1, piperidine, and wood-flour, is used to laminate plywood: (13) sulphite paper is impregnated with the product of example 1 and piperidine and laminated.