Modified binder polymer for coating compostions

Abstract

A film-forming binder polymer for a coating composition such as a paint, varnish or woodstain where the polymer is modified by the presence of bonded moieties derived from plant gum, particularly plant fibre gum obtainable from plant fibre, especially corn fibre gum and more particularly moieties derived from proteo-xylans and/or furanose. The modified binder polymer minimises the need to use coalescing solvents without producing poor dried paint coatings which fail the scrub resistance tests also improves the opacity of the dried coating composition.

1 . A film-forming binder polymer for a coating composition wherein the polymer is modified by the presence of bonded moieties obtainable from plant gum.  
   
   
       2 . A binder polymer according to  claim 1  wherein the plant gum is obtainable from plant fibre.  
   
   
       3 . A binder polymer according to  claim 1  wherein the plant gum is obtainable from corn fibre.  
   
   
       4 . A binder polymer according to  claim 1  wherein the bonded moieties comprise proteo-xylans.  
   
   
       5 . A binder polymer according to  claim 1  wherein the bonded moieties comprise furanose.  
   
   
       6 . A binder polymer according to  claim 1  wherein the bonded moieties are chemically attached to the binder polymer.  
   
   
       7 . A binder polymer according to  claim 1  wherein the plant gum comprises a mixture of polysaccharide and protein.  
   
   
       8 . A binder polymer as claimed in  claim 1  wherein the bonded moieties are derived by adding plant gum to the polymerisation reaction mixture from which the binder polymer is formed.  
   
   
       9 . A binder polymer as claimed in  claim 8  wherein the plant gum is corn fibre gum.  
   
   
       10 . A binder polymer according to  claim 1  wherein the polymer is an aqueous dispersion of particles.  
   
   
       11 . A process for modifying film-forming binder polymers which are binder polymers for coating compositions wherein plant gum is added to the polymerisation reaction which produces the binder polymer.  
   
   
       12 . A process as claimed in  claim 11  wherein the plant gum is corn fibre gum.  
   
   
       13 . A coating composition wherein the composition comprises a modified binder polymer of  claim 1 .  
   
   
       14 . A coating composition according to  claim 13  wherein the composition further contains at least one component selected from the group consisting of pigments, fillers, extenders, rheological modifiers, dispersants, antifoams, flow aids, crosslinkers and biocides.  
   
   
       15 . A coating composition according to  claim 14  wherein the selected component is pigment.  
   
   
       16 . A coating composition according to  claim 15  wherein the pigment is titanium dioxide.  
   
   
       17 . A coating composition according to  claim 16  wherein the pigment is rutile.  
   
   
       18 . A coating composition according to  claim 14  comprising a PVC(TiO 2 ) of from 5 to 35%.  
   
   
       19 . A method for improving the opacity of coating compositions wherein the method comprises employing a modified binder polymer according to  claim 1  as a binder in a coating composition.  
   
   
       20 . A method for improving the opacity of coating compositions comprising particulate non-film forming materials wherein the method comprises employing a modified binder polymer according to  claim 1  as a binder.  
   
   
       21 . A method for improving the opacity of coating compositions according to  claim 20  wherein the particulate non-film forming material is titanium dioxide.  
   
   
       22 . A method for improving the opacity of coating compositions according to  claim 20  wherein the particulate non-film forming material is rutile.  
   
   
       23 . A binder polymer according to  claim 3 , wherein the corn fiber gum is present as bonded moieties at a level in the range from 0.1 to 10 wt % based on the total binder polymer.  
   
   
       24 . A binder polymer according to  claim 2  wherein the plant gum is obtainable from corn fibre or a mixture of polysaccharide and protein and wherein the bonded moieties comprise those selected from bonded moieties comprising proteo-xylans or bonded moieties comprising furanose.  
   
   
       25 . A binder polymer according to  claim 23  wherein the bonded moieties are chemically attached to the binder polymer.  
   
   
       26 . A binder polymer as claimed in  claim 24  wherein the bonded moieties are derived by adding plant gum to the polymerisation reaction mixture from which the binder polymer is formed.  
   
   
       27 . A binder polymer according to  claim 23  wherein the polymer is an aqueous dispersion of particles.  
   
   
       28 . A coating composition wherein the composition comprises a modified binder polymer of  claim 23 .  
   
   
       29 . A coating composition according to  claim 27  wherein the composition further contains at least one component selected from the group consisting of pigments, fillers, extenders, rheological modifiers, dispersants, antifoams, flow aids, crosslinkers and biocides.  
   
   
       30 . A coating composition according to  claim 28  having a PVC(TiO 2 ) of from 5 to 35%.  
   
   
       31 . A method for improving the opacity of coating compositions wherein the method comprises employing a modified binder polymer according to  claim 23  as a binder in a coating composition.  
   
   
       32 . Coating composition of  claim 13  selected from architectural coating compositions, paints, varnishes or woodstains.  
   
   
       33 . A coating composition, comprising: 
 a) solution copolymer or dispersion copolymer of mono-ethylenically unsaturated monomers selected from acrylics, vinyls, and styrenics having bonded moieties obtainable from plant gum;    b) at least one component selected from the group consisting of pigments, fillers, extenders, rheological modifiers, dispersants, antifoams, flow aids, crosslinkers and biocides; and    c) carrier liquid.    
   
   
       34 . Coating composition of  claim 33  which includes solution copolymer or dispersion copolymer of mono-ethylenically unsaturated monomers selected from acrylics, vinyls, and styrenics.  
   
   
       35 . Coating composition of  claim 33  which is essentially free of ethylene glycol, propylene glycol, and benzyl alcohol and trimethylpentane diol isobutyrate as coalescing solvents.