Patent GB-869343-A (GB)
Title: Improvements in or relating to fluorinated silanes and siloxanes
IPC: C07F7/18
Filed: 1959-02-26
Abstract: The invention comprises fluorinated silanes of the formula CnF2n+1YmRSiHX2, where n is 2 to 18, Y is a divalent aliphatic radical containing an ester, ether, amine or amide linkage, R is a divalent aliphatic hydrocarbon radical, there being a total of less than 18 atoms, exclusive of hydrogen, in Y and R, m is 0 or 1, and X is hydrogen, halogen or a monovalent hydrocarbonoxy or halohydrocarbonoxy radical, and also comprises siloxanes consisting predominantly of the units CnF2n+1YmRSi(H)O.  The silanes are prepared by reacting the appropriate olefin with a silane HSiX3, optionally in the presence of a catalyst such as platinum, a platinum salt or a peroxide.  The starting silane preferably contains two hydrogen atoms, but when it contains only one, the addition product may be reduced with lithium aluminium hydride to give CnF2n+1 YmRSiH3 which can be reacted with an alcohol to replace some of the silicon-bonded hydrogen by alkoxy groups.  The functional Y radical may be composed entirely of the functional linkage or it may also contain a hydrocarbon portion.  Specific examples are COO, SO3, CONH, SO2NH, SO2NMe, NH, NEt, O, CH2OCHMeCH2O, COOCH2CH2O and SO2 NHCH2CH2NH.  The radicals R can be saturated or unsaturated; in the latter case, the starting fluorine compound contains either two olefinic or one or more acetylenic linkages.  The siloxanes are prepared by hydrolysis of the silanes and may contain a small proportion of other siloxane units, but the fluorine content should total at least 48% by weight.  They may contain curing catalysts such as salts of carboxylic acids, alkanolamine titanates and zirconates, water-soluble zirconium compounds and titanium and zirconium esters. The siloxanes are particularly useful for providing oil- and waterrepellent coatings by applying the polymer as such or in the form of a solution (e.g. in ether) or aqueous emulsion. Curing may be effected at room temperatures or by heating, e.g. up to 150 DEG C. The siloxane may also be prepared in situ in the base member.  The Examples describe the preparation of (1) C7F15CH2O CH2)3SiX3, where X3 is (a) Cl3, (b) H3 and (c) H and (OEt)2; and the siloxane C7H15CH2O (CH2)3Si(H)O; (2) C7H15CH2CH2SiHCl2 and the siloxane C7H15CH2CH2Si(H)O; (3) C3F7 CH2CH2SiX3, where X3 is (a) Cl3, (b) H3 and (c) H and (OEt)2, and the siloxane C3F7CH2CH2 Si(H)O; and the following silanes with their corresponding siloxanes:-C3F7CH=CHSiHCl2, C7F15COO(CH2)3SiH3, C7F15SO2O(CH2)3SiH Br2, C7F15SO2NH(CH2)3SiHF2, C7F15CO NH(CH2)3SiH(OC4H8Cl)2, C8F17CH2CH2NH (CH2)3SiHCl2, C18F37CH2OOC(CH2)10SiHCl2, <FORM:0869343/IV (a)/1> and C8 <FORM:0869343/IV (a)/2> All the siloxanes described are liquids.ALSO:The preparation of fluoro-olefins of the formula (1) CnF2n+1R1 and (2) CnF2n+1YR1, and of fluoroacetylenes of the formula (3) CnF2n+1C­CH is described, where R1 is an olefinic radical and Y is an aliphatic radical comprising an ester, ether amine or amide linkage.  To prepare (1), a perfluoro acid CnF2n+1COOH is esterified with ethyl alcohol and the ester is reacted at about 0 DEG C. with a mixture of methyl and isopropyl magnesium bromides to give CnF2n+1CHOHCH3.  This is dehydrated by heating at 200 DEG  to 300 DEG C. in the presence of P2O5 to obtain CnF2n+1CH= CH2.  Compounds of the formula (2) are prepared by the following types of reactions:  <FORM:0869343/IV (b)/1> The fluoroacetylenes (3) are prepared by adding HBr to CnF2n+1CH=CH2 to give CnF2n+1CH2CH2Br which is then brominated to CnF2n+1CH2CHBr2 which is dehydrohalogenated by heating in the presence of alcoholic KOH.  In Example 1, allyl bromide is refluxed with 1,1-dihydroperfluorooctanol in the presence of K2CO3 to give allyl-1,1-dihydroperfluorooctyl ether.  Other fluoro-olefins are specified in the examples.ALSO:Oil- and water-repellent coatings are provided on materials by coating with a fluorinated polysiloxane of unit formula CnF2n+1YmSi(H)O, where n is 2 to 18, Y is a divalent aliphatic radical containing an ester, ether, amine or amide linkage, m is 0 or 1, and R is a divalent aliphatic hydrocarbon radical, there being a total of less than 18 atoms, exclusive of hydrogen, in Y and R (see Group IV(a)).  The base members may be made from glass, ceramics, metal, and wood.  The siloxane may be applied as such or in the form of a solution (e.g. in ether) or aqueous emulsion.  It may also be formed in situ by coating with the silane which will hydrolyse to the corresponding siloxane on the surface.  The coating may be applied by dipping, spraying or brushing.  Curing catalysts may be added, and curing be effected at room temperature or by heating, e.g. up to 150 DEG C.