Styrene acrylic latex formulations

The control and reproducibility of particle size and particle size distribution is important to the quality of acrylic and styrene-acrylic latex products. Particle size has large effects on latex viscosity and the rheology of formulated products and may also exert subtle effects on the end-use peiformaiKe properties. The particle size is controlled primarily by the choice and amount of surfactant, or by the use of seed latexes. A recoit article [32] addresses the use of surfactants to control particle size in semi-continuous acrylic polymmzations. Many surfactants are reconunended by surfactant manuhicturras for the preparation of acrylic and styrene-acrylic latexes [33]. Sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sulfosuccinates and the aUtylphonl ethoxylates ate typical. The patent literature contmns many discussions of the use of single [34] or multiple [3S] polymer seed latexes to control particle size. 

Particle and colloidal stability, that is, lack of sedimoitation, stratification or phase separation, coagulation or flocculation, or changes in viscosity when the latex is stored, shipped, pumped, sprayed, formulated, etc. is required for most end-uses of acrylic and styrene-acrylic latexes. Such stability is primarily determined by the type and level of surfactants or other stabilizers and specialty or auxiliary monomers used. The trade-off is that functional materials contributing to particle and colloidal stability generally also increase water or moisture sensitivity, and there is an optimum balance for each end-use application. 

Polymer Areas Very fine particle size vinyl acetate, acrylic and styrene-acrylic latexes. Superior emulsifier for Zn-crosslinking latexes for floor finish formulations. Extremely low surfactant use levels. Excellent water-resistant properties. 

Three types of latex formulations have been prepared. The first formulation is an acrylic latex from methyl methacrylate, butyl acrylate and acrylic acid using sodium lauryl sulfate and Synperonic NP20 (an ethoxylated nonylphenol) as surfactants. The second formulation is a vinyl acrylic latex from vinyl acetate, butyl acrylate and sodium vinyl sulfonate with sodium lauiyl sulfate as the surfactant. The third formulation is a styrene acrylic latex from styrene, butyl acrylate and methacrylic acid with sodium lauryl sulfate as the surfactant. Three experimental latex formulations analogous to the three above were also prepared with AMPS sodium salt replacing acrylic acid, sodium vinyl sulfonate and methacrylic acid respectively. 

Chem. Descrip. Branched sodium dodecylbenzene sulfonate CAS 25155-30-0 EINECS/ELINCS 246-680-4 Uses Emulsifier for emulsion polymerization (SBR, vinyl acetate, vinyl chloride, styrene, and acrylic latexes), paints/coatings emulsifier, dispersant for agric. formulations surfactant for washing fruits and vegetables food pkg. adhesives, paper defoamer in food-contact paper/ paperboard emulsifier in mfg. of food-contact articles Regulatory FDA 21 CFR 175.105,175.300,175.320,176.170,176.180, 176.200,176.210,178.3400 exempt from tolerance under EPA40CFR 180.1001 (c) (e) BGA XIV compliance Properties Flakes pH 6.0-9.5 (10%) surf. tens. 32 dynes/cm ( CMC) anionic 98% act. 

Recently Saunders (39) conducted a detailed study of emulsion latices made from methyl ethyl ketoxime-blocked lEM (lEM-MEKO). Compositions investigated were styrene/-butyl acrylate/IEM-MEKO, styrene/butyl aerylate/IEM-MEKO latex formulated with active hydrogen compounds and styrene/butyl acrylate/IEM-MEKO copolymerized with vinyl acids or hydroxy monomers. The effect of urethane catalysts on the deblocking/curing reaction was also studied. 

Acrylic/styrene latex formulated with plasticizers, to provide a solvent-free mastic adhesive Mahogony to mahogany 1.2 (172) [33] ... 

It has been demonstrated that AMPS Monomer can be an effective partial replacement for siufactants and other water-soluble monomers in three common types of latex formulations acrylic, vinyl acrylic and styrene acrylic. Improved latex properties and improved scrub resistance of coatings prepared from these latices have been demonstrated. 

As we have seen, the process of emulsion polymerization is complete when micelles are absent from the aqueous dispersion. The aqueous phase surfactant concentration present in latices must therefore be less than or equal to the CMC. However, significant amounts of surfactant must be present but adsorbed at the polymer surface— indeed, estimates of (1.3-1.5) x 10 M m- on a styrene-acrylate copolymer have been made for SDS and aerosol OT at bulk phase concentrations close to the CMC [17]. In preparing complete formulations of paints and varnishes, further amounts of surfactant are usually added as wetting agents. This may well mean that surfactant solutions in the aqueous phase of latex paints are micellar. 

Styrene-butadiene, acrylonitrile-butadiene, chloroprene, and vinyl chloride emulsion (co)polymers are mainly used in their dried form. Carboxylated SBR, VAc (co)polymers, acrylics, and styrene-acrylic copolymers are used, on the other hand, as binders of formulation for several industrial applications in their dispersed form. Figure 7 shows the share of each of these families and the major industrial applications of these latexes. ... 

Uses Emulsifier for emulsion polymerization (SBR, vinyl acetate, vinyl chloride, styrene, and acrylic latexes), paints/coatings emulsifier, dispersant for agric. formulations surfactant for washing fruits and vegetables food-pkg. adhesives, paper defoamer in tbod-conlact paper/paperboard emulsifier in mfg. of food-con-tdct drticiss... 

Uses Emulsifier for latexes, emulsion polymerization, vinyl-acrylic and styrene-acrylic polymers, and min. oils detergent food-pkg. adhesives emulsifier in mfg. of food-contact articles corrosion inhibitor Features APE-free allows clear formulations Reguiatory FDA 21CFR 175.105,178.3400 BGA XIV compliance Properties Gardner 3 max. limpid liq. sol. in water and most polar solvents insol. in aromatic solvents dens. 1.04 g/cc pour pt. = 5 Cl flash pt. > 100 C pH (5% aq.) 8.0-9.0 surf. tens. 40 dynes/cm 0.03% CMC 30% cone, in water Environmentai Biodeg. 

Uses Dispersant for latex paints including low sheen flat through semi-gloss acrylic, styrene-acrylic and vinyl-acrylic formulations Features Versatile, low-cost, non-foaming effective over a pH range of 7to 11 easy to process and handle... 

Uses Antifoam for paints, latex formulations, flat and semigloss paints, vinyl acrylic, acrylic, PVAc aq. paints, water-reducible coalings based on acrylic, styrene acrylic, aq. adhesives based on acrylic, PVA, SBR Properties Off-wh. opaque liq. insol. in water disp. in surfactant systems sp.gr. 0.91... 

Many epoxy dispersions are compatible with most types of latex emulsions including acrylic, urethane, styrene butadiene, vinyl chloride, and polyvinyl acetate. The epoxy dispersion can be used as a modifier for these emulsions to alter handling and application characteristics such as emulsion rheology, foaming tendencies, pH sensitivity, wetting properties, and coating coalescence. They can also be reacted into the latex resin either by reacting the epoxy with a functionalized latex or by use of an epoxy with a coreactant. In this way adhesive systems can be formulated that are cured at room or elevated temperatures. 

Table 14.6 illustrates typical improvements noted in epoxy hybrid formulations with vinyl chloride, acrylic, and styrene butadiene lattices. Tensile strengths of cured, latex-saturated paper substrates are listed in absolute numbers while those of latex-epoxy hybrids are listed as percent increases in tensile strength over that of the latex alone. The mechanisms believed responsible for these improvements are (1) cocuring of the epoxy group with carboxyl and amine functional groups present on the latex backbone and/or (2) homopolymerization of the epoxy catalyzed by the tertiary amine included in some hybrid formulations. 

Inaba et al. prepared a series of model styrene/butyl acrylate copolymer latexes with glass transition temperatures at room temperature. The functional monomer 2-(3-isopropenylphenyl)-2-methylethylisocyanate (TMI) was used as monomer/crosslinking agent for further film formation. A small amount of methacrylic acid was introduced in some formulations in order to enhance the crosslinking reaction. A redox initiation system was used to reduce premature crosslinking during the polymerization [82]. 

Acrolein is included at 3 - 201 in a formulation including acrylic esters, styrene, and 2-hydrcxyethyl acrylate. The latex is used with tri(methoxymethyl)melamine to provide a solvent and alkali resistant coating. (62)... 

After the paper making process is complete, latexes that are useful as binders for the application of clays or CaCC>3 to paper for printing paper may be prepared using the dimer of AMS. In a typical formulation, styrene, butadiene, Me methacrylate, and acrylonitrile were emulsion polymerized in the presence of AMS dimer to obtain a copolymer latex.473 Surprisingly, the AMS dimer was used in combination with tert-dodecylmercaptan, so there may have been some residual odor. Unsaturated carboxylic acids, such as acrylic acid, or sulfonic acids, such as 2-ethylsulfonyl acrylate, or unsaturated amides, such as acrylamide, are also useful, providing the polarity necessary in these applications.474... 

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