Primers latex

Water-based paints are dispersions based on synthetic polymers. Dispersions of polyacrylates are the most common. Examples of these paints include acrylic latex paint, heavy-bodied latex wall paint, latex enamel, latex primer, latex wall paint and sealing water-borne paint. Water-based paints can also contain water-soluble alkyd resin and a mixture of polyacrylate and polyurethane. Although water is the main solvent in these types of paints, comprising about 30-85% weight-to-weight ratio (w/w) of the raw materials, about 10% organic solvents are added to improve the film forming properties of the paint. (Hansen et al. 1987 van Faassen and Borm 1991 Wieslander et al. 1997). The differences between SBP and WBP can be seen in Table 2. 

Aqueous dispersions are used in fiber bonding, paper coating, friction and abrasive appHcations, and laminates and wood bonding. PhenoHc dispersions improve the strength of latex-contact adhesive appHcations. Epoxy-modified phenoHc dispersions are prepared by dispersion of the phenoHc epoxy resin. The systems are used for baked primer appHcations and bonding requirements. Minimum baking conditions are 20 min at 150°C (25). 

Paint films exposed to condensation often fail unexpectedly by very early blistering between primer and finishing coat, usually associated with soluble salts trapped under the relatively impermeable finishing coat. Relatively more permeable latex-based paints are less prone to this failure. 

An acrylate modified vinyl chloride - vinylidene chloride latex copolymer (Haloflex 202) has been developed in our laboratory (1,2) specifically for the preparation of water-borne anti-corrosive primer paints. This carefully designed copolymer, hereafter... 

Substrates, Paints and Coatings. Both flash rusting and underfilm darkening studies exployed a white, pH 4.5, primer formulation (see Appendix), designated as Standard, based upon Haloflex 202, a chlorine-containing vinyl acrylic latex. A zinc phosphate free formulation, designated as Non-Standard, of pH6 was prepared by substitution of zinc phosphate for barytes. The comparison paints were a commercial butyl acrylate-methyl methacrylate water borne primer, formulated at pH 9, and a solvent based chlorinated rubber primer. 

Primer Formulation Based on Chlorine Containing Vinyl Acrylic Latex... 

Enzymatically active, partially purified (washed) rubber particles can be isolated such that, when provided with an appropriate APP primer, magnesium ion cofactor, and IPP monomer, rubber is produced in vitro [253-255]. Fresh latex can be separated by centrifugation into three phases. The bottom fraction (20% of the latex) contains membrane-bound organelles. The middle fraction is called the C-serum. The top fraction phase contains the rubber particles. Biochemical smdies have established that latex in this fractionated form is unstable. These smdies also suggest that the bottom fraction is required for initiation of polymer synthesis. 

The mixtures were placed in transparent round latex flasks. Initiation was in the center. With their method, it was possible to record spherical detonation waves whose velocities were the same as when these mixtures were detonated in tubes. The waves usually originated very near the ignition source (electric spark or electric primer), but in some cases there was a brief predetonation period... 

Paints. Although most drying oils have been replaced as paint vehicles hy latexes and other synthetic resins, oils are still being used to a degree in paint and allied products. In exterior house paints, linseed oil or oxidizing alkyds are used when paint must be applied al temperatures as low as 4 to 5 C, i.c. temperatures at which latexes do not coalesce satisfactorily They also arc used in primers over chalky surfaces where latex paints do nol provide adequate adhesion. 

Inhibitive Primers. The traditional primers are red lead and linseed oil, alkyd resins and zinc potassium chromate, proprietary epoxy, alkyd, urethane and latex systems with modified phosphate, borate and molybdate pigments. Chromate-based pigments, although in use in aircraft coatings, automotive primers and coil coating primers, are subject to environmental concern on the toxicity of hexavalent chromium which is likely to result in their replacement by innocuous products. 

Volatile organics in the coating film are deemed unacceptable from the environmental point of view and are giving way to water-based inhibitive primers. Some examples of water-based primers are of the acrylic latex type, as well as epoxies and water-borne... 

The properties of the latices and the paints produced from them were evaluated by several commercial firms. Ihe latex properties varied somewhat from sample to sample but, in general, the paints produced from the latexes were comparable to those produced from high-grade commercial latexes made by conventional means. One property of the paint produced from the radiation-catalyzed latex, enamel holdout, which is one measure of the capability of a paint to serve as a primer for enamel on unpainted wood, was superior to that of paint made from conventionally produced latex. 

Primer A compatible coating designed to enhance adhesion. Redispersible powder Polymers typically produced by spray-drying isolation of the specially designed latex such as those of acrylics, vinyl acetate, etc. Depending on the nature of the resin type, a suitable amount of inorganic filler is added to the powders to prevent caking. 

Most paint formulations consist of disperse systems (solid in liquid dispersions) [2]. The disperse phase consists of primary pigment particles (organic or inorganic) which provide the opacity, colour and other optical effects these are usually in the submicron range. Other coarse particles (mostly inorganic) are used in primers and undercoats to seal the substrate and enhance adhesion of the top coat The continuous phase consists of a solution of polymer or resin which provides the basis for a continuous film that seals the surface and protects it from the outside environment Most modem paints contain latexes which are used as film formers. These latexes - which typically have a glass transition temperature (Tg) below... 

A second generation of phenolic dispersions, patented by J. S. Fry (33). involved the post dispersion of phenolic resins in a mixture of water and water-miscible solvents. To conform with air pollution regulations, the solvent was held to 20 volume %, or less, of the volatiles. A heat-reactive phenolic resin dispersion (34) and a phenolic-epoxy codispersion have become commercially available based on the above technology. Supplied at 40-45% solids, these products, which have a small particle size (0.75-1.0 ym), are better film formers than the earlier dispersions. Used alone or in blends with other waterborne materials, corrosion-resistant baking coatings may be formulated for coil coating primers, dip primers, spray primer-surfacers, and chemically resistant one-coat systems. Products of this type are also tackifiers for acrylic latexes, and such systems have been employed as contact, heat seal, and laminating adhesives for diverse substrates. 

Surface chemical changes occur very rapidly when wood is exposed to the natural weathering process. Studies on the effect of short periods of weathering before finishing (9, 10) showed that adhesion of both an acrylic latex and an alkyd-oil primer to wood was significantly reduced after the wood substrate had weathered for 4 or more weeks before painting. Reduced paint adhesion and increased failure of the wood-paint interface will inevitably result in poor long-term paint and finish performance. These studies conclude that wood should be protected with a finish that will prevent... 

In the case of natural rubber from Hevea brasiliensis, which is almost entirely made of cis-isoprene units, it could be assumed that ci5-prenyltransferase is exclusively involved in phase 2. Unfortunately it is more complex. Authors agree on phase 1, which is traws -condensation catalyzed by a cytosolic soluble trans-prenyl transferase" Famesyl diphosphate synthase has been cloned from rubber latex.The most probable prenyldiphosphate used as a primer for phase 2 is famesyl-PP (15) or geranylgeranyl-PP (16)." " Phase 2 is catalyzed by a still not clearly identified rubber transferase system. Different proteins have been... 

The synthesis site for allylic diphosphate primers and cw-polyisoprene is largely assumed to occur on the surface of pre-existing rubber particles, but rubber biosynthesis activity has also been localized in the membrane of non-rubber particles from the bottom fraction after ultracentrifugation of latex. " The latter authors " presumed that previous localization of rubber biosynthesis on rubber particles was due to an artefact resulting from the rapid deterioration of bottom fraction (BF) particles after tapping, which led to the migration of rubber synthesis machinery from BF particles to rubber particles. 

Uses Defoamer for water-reducible emulsion and latex systems, high gloss architectural paints, wood preservative stains, aq. flexographic inks, primers, acid catalyzed systems, automotive basecoats, coating colors (folding boxboard), wastewater treatment Properties Lt. yel. si. vise, translucent liq. sol. in butanol, glycol ethers, ethoxypropanol, hexanol, isobutanol, IPA, methoxypropanol, MEK, min. spirits, xylene partly sol. in acetone, ethanol dens. 1.01 g/ml (20 C) flash pt. > 200 C pH = 7.0 (2% in Dl water) nonionic 100% act. 

CAS 772743-7 EINECS/ELINCS 231-7844 Uses Extender, pigment for gloss enamels, powd. coatings, semigloss latexes, house paints, primers filler in many plastics applies., in rubber goods, and in ceramics Regulatory DOT nonregulated... 

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