Hydrophobic block – random block copolymer emulsion polymer stabilizers

Abstract

A copolymer includes a hydrophobic head segment and a random copolymer tail segment comprising hydrophobic blocks and ionizable blocks. Emulsion polymerization systems incorporate the copolymer as a surfactant.

1 .- 43 . (canceled) 
     
     
         44 . A polymer dispersion system comprising:
 water; and   a water-dispersible block copolymer comprising:   a Block A, which is a hydrophobic block that comprises a homopolymer based upon styrenic repeat units; and   a Block B, which is a random amphiphilic block comprising a random distribution of hydrophobic repeat units and partially neutralized ionizable repeat units, wherein from greater than 5% to about 95% of the ionizable repeat units are neutralized.   
     
     
         45 . The polymer dispersion system of  claim 44 , wherein the styrenic repeat units are styrene, α-methyl styrene, or a copolymer thereof. 
     
     
         46 . The polymer dispersion system of  claim 44 , wherein the hydrophobic repeat units are styrenic repeat units. 
     
     
         47 . The polymer dispersion system of  claim 44 , wherein the hydrophobic repeat units comprise styrene, α-methyl styrene, an acrylate, a methacrylate, or a copolymer of any two or more thereof. 
     
     
         48 . The polymer dispersion system of  claim 44 , wherein the Block B comprises a carboxyl group. 
     
     
         49 . The polymer dispersion system of  claim 44 , wherein the ionizable repeat units comprise methacrylic acid, acrylic acid, vinyl benzoic acid, vinyl acetic acid, maleic anhydride, maleic acid, maleate, fumarate, crotonic acid, itaconic acid, fumaric acid, citraconic anhydride, mono 2-(methacryloyloxy) ethyl phthalate, mono 2-(methacryloyloxy) ethyl succinate, mono 2-(acryloyloxy) ethyl succinate, salts thereof, or a combination of any two or more thereof. 
     
     
         50 . The polymer dispersion system of  claim 44 , wherein the Block B comprises an ester comprising 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2,3-hydroxypropyl acrylate, 2,3-hydroxypropyl methacrylate, 2,4-hydroxybutyl acrylate, 2,4-hydroxybutyl methacrylates, methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, n-butyl acrylate, iso-butyl acrylate, t-butyl acrylate, n-amyl acrylate, iso-amyl acrylate, isobornyl acrylate, n-hexyl acrylate, 2-ethylbutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, methylcyclohexyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, i-propyl methacrylate, i-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, i-amyl methacrylate, s-butyl-methacrylate, t-butyl methacrylate, 2-ethylbutyl methacrylate, methylcyclohexyl methacrylate, cinnamyl methacrylate, crotyl methacrylate, cyclohexyl methacrylate, cyclopentyl methacrylate, 2-ethoxyethyl methacrylate, isobornyl methacrylate, or a combination of any two or more thereof 
     
     
         51 . The polymer dispersion system of  claim 44 , wherein the Block B comprises acrylic acid;
 a mole percentage of acrylic acid units in the Block B (f AA ) is from 21% to 52%; and   an overall mole percentage of acrylic acid units in the water-dispersible block copolymer (F AA ) is from 14% to 26%.   
     
     
         52 . The polymer dispersion system of  claim 44 , wherein the water-dispersible block copolymer consists of a single Block A and a single Block B. 
     
     
         53 . The polymer dispersion system of  claim 44 , wherein the water-dispersible block copolymer has a number average molecular weight from 5,000 to 20,000 g/mol. 
     
     
         54 . The polymer dispersion system of  claim 44 , wherein:
 the Block A is polystyrene, poly-α-methyl styrene or a copolymer of thereof; and   the Block B is a random copolymer of:   a first monomer selected from the group consisting of styrene, α-methyl styrene, an acrylate, a methacrylate, or a mixture of any two or more thereof; and   a second monomer having an ionizable group selected from the group consisting of a carboxylic acid.   
     
     
         55 . The polymer dispersion system of  claim 44 , wherein the water-dispersible block copolymer comprises polystyrene-b-(poly(styrene-r-acrylic acid)), poly-α-methylstyrene-b-(poly(styrene-r-acrylic acid)), poly(butyl acrylate)-b-poly(styrene-r-acrylic acid), poly(butyl acrylate)-b-poly(butyl acrylate-r-acrylic acid), polystyrene-b-poly(butyl acrylate-r-acrylic acid), poly(methyl methacrylate-r-butyl acrylate)-b-poly(butyl acrylate-r-acrylic acid), or poly(styrene-r-butyl acrylate)-b-poly(butyl acrylate-r-acrylic acid). 
     
     
         56 . The polymer dispersion system of  claim 44 , which is free of small molecule surfactants. 
     
     
         57 . The polymer dispersion system of  claim 56 , wherein the small molecule surfactants have a molecular weight of 3000 g/mol or less. 
     
     
         58 . The polymer dispersion system of  claim 44 , wherein from 20% to 95% of the ionizable groups are neutralized. 
     
     
         59 . The polymer dispersion system of  claim 44 , comprising:
 from 1 wt. % to 60 wt. % of the water-dispersible block copolymer.