Method for acylating a hydroxylated solid material

Abstract

A method for chromatogenic acylation of a solid material carrying hydroxyl groups capable of reacting with fatty acid chlorides in the gaseous state, wherein a reactive fatty acid chloride composition is applied to the surface of the solid hydroxyl material by means of an applicator capable of releasing the composition on the surface of the material. The composition is applied to the surface of the solid hydroxyl material at an acylation temperature lower than the vaporization temperature of at least one fatty acid chloride of the composition to allow acylation of the material by reaction of at least one fatty acid chloride in the gaseous state of the composition with at least one of the hydroxyl groups of the material, the acylation temperature being between 160° C. and 250° C.

1 . A process for the chromatogenic acylation of a solid material bearing hydroxyl groups that are accessible to at least one fatty acid chloride in the gaseous state and that are capable of reacting with this (these) fatty acid chloride(s) in the gaseous state, wherein:
 at least one composition, referred to as reactive composition, of at least one fatty acid chloride is applied at least on the surface of said hydroxylated solid material by means of at least one applicator device having an application surface formed of filiform elements that are not reactive with said reactive composition and that are able to release said reactive composition at least on the surface of said hydroxylated solid material by contact of the filiform elements and the hydroxylated solid material,   said reactive composition applied by the applicator device at least on the surface of said hydroxylated solid material is, during the application thereof, at a temperature, referred to as acylation temperature, below the vaporization temperature of at least one fatty acid chloride of said reactive composition and chosen to enable an acylation of said solid material by reaction of at least one fatty acid chloride in the gaseous state of said reactive composition with at least one of the hydroxyl groups of said solid material, said acylation temperature being between 160° C. and 250° C.   
     
     
         2 . The process as claimed in  claim 1 , wherein at least one application surface portion of the applicator device is in contact with a surface portion of the hydroxylated solid material, at least this surface portion of the hydroxylated solid material is at said acylation temperature during application of said reactive composition to the hydroxylated solid material. 
     
     
         3 . The process as claimed in  claim 1 , wherein the filiform elements forming the application surface are at said acylation temperature during the application of said reactive composition to the hydroxylated solid material. 
     
     
         4 . The process as claimed in  claim 1 , wherein said reactive composition is applied at least on the surface of said hydroxylated solid material, in a thermoregulated chamber suitable for maintaining said reactive composition released by the applicator device at said acylation temperature. 
     
     
         5 . The process as claimed in  claim 1 , wherein the process further comprises at least one step of redistributing fatty acid chloride(s) deposited on the hydroxylated solid material, without a fresh supply of said reactive composition, the redistribution step being carried out by means of at least one distributor device having an application surface formed of filiform elements which are not reactive with the fatty acid chlorides of said reactive composition and are able to be loaded with fatty acid chlorides deposited on the hydroxylated solid material, by contact of the filiform elements of the distributor device with the hydroxylated solid material and in order to release at least some of the loaded fatty acids, in contact with said hydroxylated solid material by contact of the filiform elements with the hydroxylated solid material, the distributor device being at a temperature of between 160° C. and 250° C. 
     
     
         6 . The process as claimed in  claim 1 , wherein at least one reactive composition comprises at least one fatty acid chloride chosen from the group formed of palmitic acid chloride, stearic acid chloride, arachidic acid chloride and behenic acid chloride. 
     
     
         7 . The process as claimed in  claim 1 , wherein the hydroxylated solid material is a paper material. 
     
     
         8 . The process as claimed in  claim 1 , wherein the hydroxylated solid material is formed of a paper web moved in a run direction parallel to the largest dimension of the web, between an upstream reel of said paper web and a downstream take-up roll for a web of acylated paper. 
     
     
         9 . The process as claimed in  claim 8 , wherein at least one reactive composition is applied at fixed station(s) at least on one main face of the moving paper web. 
     
     
         10 . The process as claimed in  claim 8 or 9, claim 8 , wherein at least one applicator device is a roller with an axis of rotation parallel to the plane of the paper web and not parallel to the run direction. 
     
     
         11 . The process as claimed in  claim 8 , wherein the process further comprises at least two applications of reactive composition(s) at fixed stations on the moving paper web, each reactive composition being at said acylation temperature during the application thereof. 
     
     
         12 . The process as claimed in  claim 8 , wherein the solid material is a paper material coated with polyvinyl alcohol. 
     
     
         13 . The process as claimed in  claim 8 , wherein the filiform elements of at least one applicator roller are supplied by centrifugal diffusion of said reactive composition from an axial lumen of this applicator roller rotated upon itself. 
     
     
         14 . The process as claimed in  claim 13 , wherein said reactive composition is introduced into the axial lumen of the applicator roller by means of a bar for distributing said reactive composition over the length of the axial lumen, the distribution bar extending over substantially the entire length of the axial lumen. 
     
     
         15 . The process as claimed in  claim 8 , wherein at least one applicator roller is provided with means for heating said reactive composition to said acylation temperature. 
     
     
         16 . The process as claimed in  claim 8 , wherein a withdrawal of fatty acid chloride(s) on the paper web is carried out using a recovery device having a rotatable recovery surface provided with filiform elements which are not reactive with said reactive composition and are able to:|
 be loaded with fatty acid chloride(s) by contact of the recovery surface and the paper web, and   release fatty acid chloride(s) by applying a flow of gaseous composition heated to a temperature above said acylation temperature, the flow of gaseous composition being applied in contact with the recovery surface.   
     
     
         17 . The process as claimed in  claim 1 , wherein the filiform elements are formed from at least one material chosen from the group formed of aramid fibers and microfibers and inorganic fibers and microfibers. 
     
     
         18 . The process as claimed in  claim 1 , wherein at least one portion of gaseous hydrochloric acid formed due to the chromatogenic acylation is entrained by a flow of a gaseous composition circulating in contact with the solid material, at said acylation temperature. 
     
     
         19 . The process as claimed in  claim 1 , wherein said reactive composition is free of any solvent medium.