Water/oil-repellent treatment agent having heat resistance, method of preparation, and treated article

A water/oil repellent treatment agent comprising at least one compound selected from the group consisting of fluorooxyalkylene group-containing polymer-modified silanes of general formulas (1) to (4) below

• A-Rf-QZWα (1)
• Rf-(QZWα)2 (2)
• A-Rf-Q-(Y)βB (3)
• Rf-(Q-(Y)βB)2 (4),
• wherein Rf is —(CF2)d—(OCF2)p(OCF2CF2)q(OCF2CF2CF2)r(OCF2CF2CF2CF2)s(OCF(CF3)CF2)t—O(CF2)d—, each d being independently an integer from 0 to 5, p, q, r, s and t being each independently an integer from 0 to 500, with the proviso that the sum p+q+r+s+t=40 to 500, and each unit shown in parentheses being randomly bondable;
• A is a fluorine atom, a hydrogen atom, or a monovalent fluorine-containing group having a terminal —CF3 group, —CF2H group or —CH2F group;
• Q is independently a single bond or a divalent organic group which may be fluorine-substituted and does not contain a hydrocarbon ether bond;
• Z is independently a group selected from the group consisting of a single bond, the divalent group -J2C— (where J is independently an alkyl group, a hydroxyl group or the silyl ether group K3SiO— (K being independently a hydrogen atom, an alkyl group, an aryl group or an alkoxy group), the divalent group -L2Si— (where L is independently an alkyl group, an alkenyl group, an alkoxy group or a chloro group), the trivalent group -JC═ (where J is as defined above), the trivalent group -LSi═ (where L is as defined above), the tetravalent group —C≡, the tetravalent group —Si≡, and siloxane residues having a valence of 2 to 8;
• W is independently a hydrolyzable group-bearing moiety of any of general formulas (5a) to (5e) below
• R being independently an alkyl group of 1 to 4 carbon atoms or a phenyl group, X being independently a hydrolyzable group, the letter “a” being 2 or 3, the letter “l” being an integer from 0 to 10, each m being independently an integer from 1 to 10, D being a single bond or a divalent organic group of 1 to 20 carbon atoms which may be fluorine-substituted, b being an integer from 2 to 6, c being an integer from 1 to 50, and Me being a methyl group;
• α is an integer from 1 to 7;
• Y is independently a divalent group having a hydrolyzable group;
• β is in each instance an integer from 1 to 10;
• and
• B is independently a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, or a halogen atom,
• and partial (co)hydrolyzates/condensates thereof in an amount of at least 50% of the total weight exclusive of diluting solvent, wherein the treatment has a percent weight loss after one hour of exposure at 250° C. that is not more than 10% of the total weight exclusive of diluting solvent.