Fluorocarbon-containing compounds and method of imparting oil-and water-repellency to textiles,paper,leather and the like

Abstract

Abstract The compounds of formula (I) may be obtained by different processes depending upon the different nature of the starting chemical intermediates. Obviously, the molecule as represented by formule (I) is formed by: WHEREIN: X is bonded to an alkylene group and is selected from the group consisting of -H, -OCH3, -OC2H5, -OC3H7 and -OCH(CH3)2; Y is bonded to an N atom and is selected from the group consisting of -H, -CH3, -C2H5, -C3H7 and -CH(CH3)2; Rf is a perfluorinated hydrocarbon chain -CzF2z 1 in which z is an integer from 5 to 11; a, b and c are integers from 2 to 10; n is an integer from 1 to 10, preferably from 3 to 10; m is an integer from 1 to 10; p is an integer from 1 to 5; g is an integer from 0 to 5; ( Sigma ) is a polyester- or a polyether-polyurethane chain carrying the number p of the NCO groups indicated in the formula; the number-average molecular weight (international symbol Mn; Encyclopedia of Polymer Science and Technology, VOL. 3 page 653 and Vol. 9 page 182) of the compound not exceeding 60,000. This invention also covers precursors of the compounds as defined above, wherein the NCO groups are temporarily blocked by phenol or other suitable blocking agents. Advantageously, the number-average molecular weight of the compounds according to this invention amounts to at least 3,500. When, in the formula (I), q is zero, the compound will be a straight chain polymer, in which the n segments containing the perfluoroalkyl group Rf and the m segments containing the polyurethane chain will be distributed in the polymer chain in any order, with X radical being attached to one of the m segments and the Y radical being attached to one of the n segments. Typically, however, q will amount at least to 1, whereby the compound of formula (I) will be a branched chain polymer, having for example one of the following structures: COMPRISING A PERFLUORINATED HYDROCARBON CHAIN Rf and a polyester- or polyether urethane chain ( Sigma ) carrying free NCO groups; and precursors of said compounds, wherein the -NCO groups are temporarily blocked by phenol or another suitable blocking agent. This invention relates to the art of imparting oil-and waterrepellency properties to substrates such as textiles, paper, leather and the like by treating such substrates with compounds comprising perfluoroalkyl chains. More particularly, the invention relates to compounds wherein a perfluoroalkyl chain is affixed to an active part of the molecule capable of providing for a possibly durable bond between the said chain and the substrate. Representative examples of such compounds, known in the art, are perfluoroacyl-aziridines, perfluoroacyl-polyamines and certain fluorocarbon urethanes, the latter being obtained by reacting an organic isocyanate with a compound containing a sulphonomide group, a perfluoroalkyl terminal group and a group containing an active hydrogen. A drawback of hitherto known compounds of the character just set forth above resides in that they are insoluble in organic solvents (actually, most of them are used in the form of aqueous emulsions) or are soluble in special solvents or specific mixtures of solvents only, which are either expensive and difficult to recover (e.g., fluorinated solvents) or inflammable or strongly poisonous. It is therefore an object of this invention to provide perfluoroacyl compounds capable of durably imparting oil- and water-repellency properties to substrates, said compounds being soluble in chlorinated hydrocarbon solvents common in the art, such as tetrachloroethylene and trichloroethylene, and said properties being practically unaffected for long time by rubbing, washing, dry-cleaning and similar treatments of fabrics treated with these compounds. A further drawback of prior art compounds resides in that relatively high amounts thereof are necessary to provide effective oil- and water-repellent coatings on a substrate, while a still further drawback resides in that the said compounds are unable to impart to woollens (e.g., woollen- and part-woollen yarn and knitted were) true shrink-proofness properties, the latter being here understood in the sense established by International Wool Secretariat (area shrinkage not exceeding 4 percent). Thus, a further object of this invention is to provide perfluoracyl compounds capable of imparting both oil- and waterrepellency and shrink-proofness to wollens. Further objects and advantages will become evident to those skilled in the art from the following description. The polymeric compounds according to this invention may be represented by randomly repeating units having the general formulas: Compounds represented by a formula:

Inventors

• 👤 Sergio Lo Monaco
• 👤 Alfredo Guerrato
• 👤 Dario Fabbro
• 👤 Graziello Donadello

Bibliographic Details