Coating composition comprising autoxidisable component

Abstract

An aqueous solution coating composition comprising an autoxidisable polyvinyl polymer having ≧20% of fatty acid residue by weight of polymer; T g from −60 to +15° C.; acid value of 15 to 75 mg KOH/g, M w from 2500 to 100000 g/mol; polydispersity ≦30, said composition having ≦25% co-solvent by weight of solids, ≧30% solids by weight of composition; said composition when in the form of a coating having a telegraphing value defined as the difference in gloss at a 20° angle of between a film cast on rough PVC and a film cast on smooth PVC of 10 gloss units.

1 . An aqueous coating composition that comprises an autoxidisable polymer that comprises plurality of vinyl groups where:
 I) said autoxidisable polyvinyl polymer has:   i) fatty acid residue in an amount greater than or equal to 20% by weight of said autoxidisable polyvinyl polymer   ii) a glass transition temperature (T g ) from −60° C. to +20° C.;   iii) an acid value from 5 to 75, optionally from 15 to 75 mg KOH/g;   iv) a weight average molecular weight (M w ) from 2500 to 100000 g/mol; and   v) a polydispersity (PDi) less than or equal to 30;   II) said composition has:   a) a co-solvent content less that 25% by weight of solids;   b) a solids content greater than or equal to 30% by the total weight of said composition; and   III) said composition when in the form of the film has a telegraphing value of less than 10 gloss units,
 where the telegraphing value is the difference between an initial smooth gloss value minus an initial rough gloss value of the film, where 
   the initial smooth gloss value is the gloss when the film is cast on smooth PVC (R z =1 μm [±0.25 μm]);
 the initial rough gloss value is the gloss when the film is cast on rough PVC (R z =25 microns [μm] [±5 μm]); and where 
 each film has a dry film thickness of 52 μm [±6 μm]; and 
 each initial gloss value is measured at a 20° angle, one day (24 hours) after the film has been cast. 
   
     
     
         2 . An aqueous coating composition according to  claim 1  wherein the autoxidisable polymer if carboxylic acid functional has an ND×AV value of >22 and <65; where ND=neutralization degree of the acid groups on the polymer and AV=acid value. 
     
     
         3 . An aqueous coating composition according to  claim 1 , which comprises <13% N-methylpyrrolidone by weight of the composition. 
     
     
         4 . An aqueous coating composition according to  claim 1  comprising <13% by weight of polymer solids of nitrogen containing molecules with an evaporation rate <0.1 which are either aromatic, heterocyclic or which are aromatic and aliphatic primary and secondary (di)amines with the proviso that the weight % of nitrogen in such molecules is >5%. 
     
     
         5 . An aqueous coating composition according to  claim 1  comprising.
 i) 35% to 50% of the autoxidisable polyvinyl polymer by weight of the composition; 
 ii) 0 to 20% of co-solvent by weight of the composition; and 
 iii) 35% to 65% of water by weight of the composition; 
 
     
     
         6 . An aqueous coating composition as claimed in  claim 1  where the autoxidisable polyvinyl polymer has:
 i) fatty acid residue in an amount greater than or equal to 25% by weight of said autoxidisable polyvinyl polymer; 
 ii) a glass transition temperature (T g ) from −40° C. to +10° C.; 
 iii) an acid value from 5 to 50 mg KOH/g; 
 iv) a weight average molecular weight (M w ) from 6000 to 40000 g/mol; and 
 v) a polydispersity (PDi) less than or equal to 20; and
 where the composition has a co-solvent content <6% by weight of solids 
 
 
     
     
         7 . An aqueous coating composition according to  claim 1 , comprising:
 15% to 40% of TiO 2 ;   ii) 15% to 40% of polymer solids;   iii) 0 to 10% of co-solvent by weight of solids;   iv) 0.1 to 3% of thickener;   v) 0 to 5% dispersing agent;   vi) 25% to 70% water;   where unless indicated all percentages are by weight of the composition and i)+ii)+iii)+iv)+v)+vi)=100%.   
     
     
         8 . An autoxidisable polyvinyl polymer having:
 i) fatty acid residue in an amount greater than or equal to 20% by weight of said autoxidisable polyvinyl polymer;   ii) a glass transition temperature (T g ) from −60° C. to +20° C.;   iii) an acid value from 5 to 75, optionally from 15 to 75 mg KOH/g;   iv) a weight average molecular weight (M w ) from 2500 to 100000 g/mol; and   v) a polydispersity (PDi) less than or equal to 30; and   where the polymer is capable of forming a coating composition which when in the form of the film has a telegraphing value (as defined in  claim 1 ) of less than 10 gloss units.   
     
     
         9 . A method for preparing an autoxidisable polyvinyl polymer the process comprising the steps of:
 I) polymerising ethylenically unsaturated vinyl monomers to form a polyvinyl polymer; and   II) reacting the polyvinyl polymer obtained in step I) with fatty acids having an average iodine value in the range of 80 to 180 g I 2 /100 g fatty acid;   to obtain an autoxidisable polyvinyl polymer having   i) fatty acid residue in an amount greater than or equal to 20% by weight of said autoxidisable polyvinyl polymer;   ii) a glass transition temperature (T g ) from −60° C. to +20° C.;   iii) an acid value from 5 to 75, optionally from 15 to 75 mg KOH/g;   iv) a weight average molecular weight (M w ) from 2500 to 100000 g/mol; and   v) a polydispersity (PDi) less than or equal to 30; and   where the polymer is capable of forming a coating composition which when in the form of the film has a telegraphing value (as defined in  claim 1 ) of less than 10 gloss units.   
     
     
         10 . An autoxidisable polyvinyl polymer obtained and/or obtainable by a process as claimed in  claim 9 . 
     
     
         11 . A coating composition comprising an autoxidisable polyvinyl polymer as claimed in either  claim 8 . 
     
     
         12 . A coating composition as claimed in  claim 1  where the composition comprises:
 a) a co-solvent content ≦15% by weight of solids; 
 b) a N-methylpyrrolidone content ≦13% by weight of solids; 
 c) heterocyclic amine containing solvent content of 0 wt % by weight of solids; 
 d) a solids content ≧30% by weight of the composition; and 
 e) a pH from 4.1 to 8.4; and
 where said composition is in the form of the film, the film has a telegraphing value (as defined in  claim 1 ) of less than 10 gloss units. 
 
 
     
     
         13 . A coating composition as claimed in  claim 1 , in which the autoxidisable polyvinyl polymer is present in an amount from 38 to 65% by weight of the composition. 
     
     
         14 . A coating obtained and/or obtainable by a coating composition as claimed in  claim 1 , the coating having a telegraphing value (as defined in  claim 1 ) of less than 10 gloss units. 
     
     
         15 . A substrate coated with a coating as claimed in  claim 14 . 
     
     
         16 . A method of coating a substrate comprising the steps of
 i) applying a coating composition as claimed in  claim 1  to a substrate;   ii) drying the substrate to form a coating thereon;   where the coating has a telegraphing value (as defined in  claim 1 ) of less than 10 gloss units.   
     
     
         17 . Use of an autoxidisable polyvinyl polymer and/or a coating composition as claimed in  claim 1  for the purpose of obtaining coatings having a telegraphing value (as defined in  claim 1 ) of less than 10 gloss units. 
     
     
         18 . A method of manufacture of an autoxidisable polyvinyl polymer and/or a coating composition as claimed in  claim 1  for the purpose of obtaining coatings having a telegraphing value (as defined in  claim 1 ) of less than 10 gloss units.