Small particle latex coating

Recent improvements in the sensitivity IS) of the vacuum-suction fiberdrawing technique for elongational viscosity measurements have permitted the evaluation of cellulose-thickened coatings with a small-particle latex 16), The data (Table I) indicate that the DUEV involves contributions not only from the thickener but also from the components of the formulation. On the basis of earlier observations 17), this contribution was assumed to arise from high-aspect ratio flocculents formed by the latex and pigment in extension. 

The studies just discussed do not address one of the significant contributions associative thickeners make to coatings rheology minimizing LSVs in small-particle latex formulations. 

On the whole, the miniemulsion polymerization process proved to be effective for incorporating an alkyd resin into acrylic coated copolymers. The reaction produced stable, small particle size latexes that contain graft copolymer of the acrylic and alkyd components. Attempts at macroemulsion hybrid polymerization were unsuccessful. 

High solid content latexes with small particle size (below 100 nm), useful as waterborne coatings, could be obtained by this procedure. 

It was also shown that stable latexes of high solid content, and small particle size could be practically obtained by this emulsion polymerization technique. Such microlatexes based on acrylic polymers modified by polyesters are an interesting approach to waterborne coatings leading to high gloss paint films (9). 

In addition, two patients with recurrent bacterial infections ingested opsonized and nonopsonized particles, but only IgG-coated latex induced the stimulation of O2 consumption, Oi formation, H2O2 production, and HMP shunt activity (W3). The turning on of the metabolic stimulation would then depend on the nature of the stimulus, which could modulate a variable membrane perturbation [the ingestion of very small particles (0.088 fim diameter) have been shown to be accompanied by no change in the resting oxygen uptake (R3)]. 

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. 

In HEC-thickened formulations, low-shear-rate viscosities increase with decreasing latex particle size. This effect has been a major limitation in formulating small-particle latices. The phenomenon appears to arise from electro viscous, hydration, or flocculation effects, not a depletion layer mechanism. Associative thickeners achieve efficient viscosity in coating formulations via participation in synthesis and formulation surfactant micelles to form pseudo macromolecules and via an ion-dipole interaction between the cations of surface carboxylate groups on the latex and the ether linkages of the associative thickener. Generally, an excess of synthesis surfactant is found in the production of small-particle latices. The achievement of lower viscosities in small-particle ( 100 nm) latex coatings thickened with associative thickener appears to occur by extensive disruption of the polymer hydrophobe s participation in intermicellar networks. 

Chemokine receptor expression on the VP can be determined by Western blot using specific antibodies, by ELISA on VP-coated plates, or by flow cytometry. In this last case, small particle size limits measurement of the surface proteins by conventional techniques, and particles are coupled to latex beads to allow detection. 

Latex They constitute an intermediate stage of the bulk of synthetic elastomers, both from a volume and a value standpoint, which are produced today. While varying obviously in composition, the various systems are analogous to natural rubber lattices in that they are an aqueous dispersion of small particles of the particular elastomer. One of the principal advantages of latex technology resides in the fact that it is the oldest method for the fabrication of elastomer or elastomeric coated goods. Thus much of the considerable technology developed for natural rubber lattices was adaptable to synthetic elastomers as they appeared. 

This approach was further extended to P(MAA-co-S)-SGl macroalkoxyamines employed for the emulsion copolymerization of MMA with a low percentage of styrene at temperamres below 90 ° Fast polymerizations led to well-controlled polymers and high initiating efficiencies due to the high dissociation rate constant of the macroalkoxyamines. Self-assembly of the formed amphiphilic block copolymers led to small particles (Dz<100nm). Besides, PEG-based macroalkoxyamines obtained from terpolymerization of MAA, MePEGMA and a few percent of S were involved in the synthesis of PEG-coated, amphiphilic diblock copolymer latexes. °... 

An example of heteroflocculation between large and small particles is that between day and cationic latex. Kaolin clay fully coated by polystyrene latex (U2 = 65 nm) is shown in Figure 1.11. At lower latex dosages, less than required for full coverage, the latex acts as a cationic polyelectrolyte, flocculating the clay. This can be seen in Figure 1.12, where the stability ratio W= 1/a, is shown as a function of latex addition, together with the electrophoretic mobility of the clay. 

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