Process for imparting grease, oil and water repellence to substrates
A process for imparting grease, oil and water repellence to a substrate comprises applying by means of a printing process on at least a portion of the surface of such substrate a composition comprising at least one (per)fluoropolyether derivative. By means of such process it is possible to confer suitable grease, oil and water repellence properties to substrates via selective treatment/coating, by significantly reducing total amount of fluoro-containing additive required for the target properties.
1. A process for imparting grease, oil and water repellence to a cellulosic substrate, said process comprising:
applying by means of a gravure method printing process on at least a portion of the surface of said cellulosic substrate a composition comprising from about 1 to 2 percent by weight of at least one (per)fluoropolyether derivative; and
subjecting at least one surface of the substrate that did not have (per)fluoropolyether derivative applied by means of the gravure printing method to at least one further processing condition;
wherein the (per)fluoropolyether derivative complies with formula: T-O—R f1 -T, wherein each of T, equal or different at each occurrence is —CF 2 —COOXa or —CF 2 CF 2 —COOXa; R f1 is a (per)fluoropolyoxyalkylene chain comprising recurring units (R o ), said recurring units (R o ) statistically distributed along the chain being one or more units selected from the group consisting of (CFXO), (CF 2 CF 2 O), wherein X═F, CF 3 ; Xa is H, a metal, or an ammonium group of formula N(R p ) 4 , wherein each of R p is H.
2. The process of claim 1 , wherein the dry amount of the at least one (per)fluoropolyether derivative applied onto the cellulosic substrate is about 0.019 to 0.027 percent by weight of the cellulosic substrate.
3. The process of claim 1 , wherein the at least one further processing condition comprises gluing or printing at least one surface of the cellulosic substrate not possessing (per)fluoropolyether derivative.