Aqueous silicone dispersions, formulations, especially paint formulations, containing them and one of their methods of preparation

Abstract

The invention relates to an aqueous silicone dispersion, containing one or more polyorganosiloxanes (POSs) intended to be crosslinked or having been crosslinked by elimination of water or alcohol, according to a polycondensation mechanism. The present invention also relates to methods for preparing aqueous silicone emulsions and dispersions.

1 . An aqueous silicone dispersion comprising:
 a) at least one polyorganosiloxane resin (A) comprising condensable hydroxyl substituents present in an amount of at least 0.05% by weight;   b) at least one epoxy-functionalized polyorganosiloxane (B);   c) at least one water-soluble hydroxylated alkylaminosilane (C) present in its monomeric form of general formula (I) and/or in a condensed oligomeric type form:   
     
       
         
         
             
             
         
       
       in which formula: 
       —R 1  is an aminoalkyl radical having 1 to 6 carbon atoms or a group of general formula: H 2 N—(CH 2 ) x R 2 —(CH 2 ) z —; with R 2  representing O, S, —NH— or NH—CH 2 —CH 2 —NH— and x≧2, z≧2; 
       d) at least one surfactant (S); 
       e) optionally at least one biocide (D); 
       f) water; and 
       g) optionally an effective amount of a polycondensation catalyst; 
       wherein said aqueous silicone dispersion does not contain a silane having hydrolyzable functional groups of alkoxy —OR type with R being a C 1 -C 20  aliphatic hydrocarbon group. 
     
   
   
       2 . The aqueous silicone dispersion as claimed in  claim 1 , comprising:
 a) at least one polyorganosiloxane resin (A) comprising condensable hydroxyl substituents present in an amount of at least 0.05% by weight;   b) at least one epoxy-functionalized polyorganosiloxane (B);   c) at least one water-soluble hydroxylated alkylaminosilane (C) present in its monomeric form of general formula (I) and/or in a condensed oligomeric type form:   
     
       
         
         
             
             
         
       
       in which formula: 
       —R 1  is an aminoalkyl radical having 1 to 6 carbon atoms or a group of general formula: H 2 N—(CH 2 ) x R 2 —(CH 2 ) z —; with R 2  representing O, S, —NH— or NH—CH 2 —CH 2 —NH— and x≧2, z≧2; 
       d) at least one surfactant (S); 
       e) optionally at least one biocide (D); and 
       f) water; 
       wherein said aqueous silicone dispersion does not contain a silane having hydrolyzable functional groups of alkoxy —OR type with R being a C 1 -C 20  aliphatic hydrocarbon group. 
     
   
   
       3 . The aqueous silicone dispersion as claimed in  claim 1  wherein the aqueous dispersion is in the form of an oil-in-water emulsion. 
   
   
       4 . The aqueous silicone dispersion as claimed in  claim 1  wherein the water-soluble hydroxylated alkylaminosilane (C) is present up to 15% by weight relative to the total weight of the dispersion, preferably present up to 10% and even more preferably between 0.5 and 7% by weight. 
   
   
       5 . The aqueous silicone dispersion as claimed in  claim 1  wherein the epoxy-functionalized polyorganosiloxane (B) comprises at least one epoxy-functional radical Y, linked to the silicon via a divalent radical containing from 2 to 20 carbon atoms and possibly containing at least one heteroatom, preferably oxygen, bearing at least one epoxy unit, Y preferably being chosen from the following radicals: 
     
       
         
         
             
             
         
       
     
   
   
       6 . The aqueous silicone dispersion as claimed in  claim 1  wherein the epoxy-functionalized polyorganosiloxane (B) is comprised of one or more units of formula (V) or is comprised of one or more units of formula (V) and is terminated by one or more units of formula (VI): 
     
       
         
         
             
             
         
       
       in which:
 the R 1  symbols are the same or different and represent:
 a linear or branched alkyl radical containing 1 to 8 carbon atoms, the alkyl radicals preferably being methyl, ethyl, propyl and octyl; 
 an optionally substituted cycloalkyl radical containing between 5 and 8 cyclic carbon atoms; 
 an aryl radical containing between 6 and 12 carbon atoms which may be substituted, preferably a phenyl or dichlorophenyl radical; or 
 an arylkyl part having an alkyl part containing between 5 and 14 carbon atoms and an aryl part containing between 6 and 12 carbon atoms, optionally substituted on the aryl part by halogens, alkyl groups and/or alkoxy groups containing 1 to 3 carbon atoms; and 
 
 the Y′ symbols are the same or different and represent:
 the group R 1 ; or 
 an epoxy-functional group, linked to the silicon of the polyorganosiloxane via a divalent radical containing from 2 to 20 carbon atoms and which may contain at least one heteroatom, preferably oxygen; and 
 at least one of the Y′ symbols represents an epoxy-functional group. 
 
 
     
   
   
       7 . The aqueous silicone dispersion as claimed in  claim 5 , wherein the epoxy-functional groups of the epoxy-functionalized polyorganosiloxane (B) are chosen from the following groups: 
     
       
         
         
             
             
         
       
     
   
   
       8 . The aqueous silicone dispersion as claimed in  claim 1 , wherein the polyorganosiloxane resin (A) comprises, before emulsification:
 condensable hydroxyl substituents present in an amount of at least 0.05% by weight; and   D, T and optionally M and/or Q siloxyl units, the T siloxyl units being present in a molar % between 50 and 85% and preferably between 55 and 80%.   
   
   
       9 . The aqueous silicone dispersion as claimed in  claim 8 , in which the polyorganosiloxane resin (A) is a liquid polyorganosiloxane resin of T(OH), DT(OH), DQ(OH), DT(OH), MQ(OH), MDT(OH), MDQ(OH) type or mixtures thereof, and preferably MDT(OH), DT(OH) or mixtures thereof. 
   
   
       10 . A method of preparing an aqueous silicone dispersion, comprising:
 a) preparing   a premix I comprising at least one polyorganosiloxane resin (A) as claimed in  claim 1  and a premix II comprising at least one epoxy-functionalized polyorganosiloxane (B) as claimed in  claim 1  or
 a premix III comprising at least one polyorganosiloxane resin (A) as claimed in  claim 1  and at least one epoxy-functionalized polyorganosiloxane (B) as claimed in one of  claim 1 ; 
   b) emulsifying with water and in the presence of at least one surfactant (S):
 premix I and II obtained in step a); or 
 premix III obtained in step a); and 
   c) mixing:
 the emulsion obtained in step b) with at least one water-soluble hydroxylated alkylaminosilane (C) as claimed in  claim 1 ; and 
   d) optionally curing the dispersion of step c) so that crosslinking in the emulsion occurs.   
   
   
       11 . An aqueous formulation, comprising:
 an aqueous silicone dispersion as claimed in  claim 1 , said silicone dispersion present in an amount up to 150% by weight relative to the total weight of one or more organic dispersions;   a siliceous or nonsiliceous filler, selected from the group consisting of: precipitated silica, unprecipitated silica, colloidal or powdered silica, carbonates, talc, TiO 2  and mixtures thereof; and   at least one of the compounds listed below:   one or more organic dispersions selected from the group consisting of (co)polymers of styrene and/or (meth)acrylic acid or a combination thereof;   one or more thickeners selected from the group consisting of acrylic cellulose thickeners, polyurethanes, natural gums and mixtures thereof;   one or more coalescents, selected from the group consisting of organic solvents glycols, aliphatic petroleum cuts and mixtures thereof;   one or more wetting agents or dispersants selected from the group consisting of phosphates, polyacrylics and a combination thereof;   one or more tension agents;   one or more neutralizing agents;   one or more biocides;   one or more diluents;   one or more plasticizers, selected from non-reactive silicone oils;   one or more antifoaming agents; and   one or more pigments or dyes.   
   
   
       12 . A paint comprising the aqueous silicone dispersion as claimed in  claim 1 . 
   
   
       13 . (canceled) 
   
   
       14 . A paint comprising the aqueous silicone dispersion obtained in  claim 1 . 
   
   
       15 . A paint comprising the aqueous silicone formulation as claimed in  claim 11 .