Coating polymer latexes used

In all cases, the operations for preparing PCC are similar to those used for common concrete and mortar. Curing, however, is different. After only 1 day of moist cure, the surface of PCC work can be uncovered. The film already formed on the surface retains the necessary amount of moisture for the full hydration of the cement. In principle, after only a few days of air cure at around the normal ambient temperature (20°C), the PCC can be put in service. The polymer latex used for making a PCC must be able to form a film under ambient conditions, coat cement grains and aggregate particles, and form a strong bond between the cement particles and aggregates. 

The largest industrial uses of polymer latexes are latex paints and adhesives, but other major applications include paper coatings and textiles. Latex paints mostly involve acryhc polymers, while natural and synthetic styrene-butadiene rubbers (SBR) are the main binders of latex adhesives. The most common types of polymer latexes used in coating applications are listed in Table 4.1. 

Coa.ting S. CR has been used to coat a variety of substrates, from cloth for rainwear to concrete decks for protection against salt water. A sol-type latex is preferred to ensure good adhesion to concrete decks. A crystalline polymer latex is preferred where added durabUity is needed. The compound includes a nonionic surfactant to improve its chemical stabUity. A number of thin coatings are appUed to the surface to allow better coverage and facUitate drying. A similar formulation could be used to coat the interior of tanks, but an accelerator is needed to improve toughness. 

Aqueous polynitrile oxide curing compositions, with good storage stability, have been patented (525). The compositions comprise aqueous dispersions containing nitrile oxides and are useful for coating systems that are cured at room temperature without the release of byproducts. Latexes are cured by mixing a polymer latex with a stable polynitrile oxide, for example, 2,4,6-triethylbenzene -1,3-dicarbonitrile oxide, and removing water from the mixture. 

Polyvinylacetate (PVAc) has not been used in the pharmaceutical held until recently. During the polymerization, especially at high conversion, free radicals are transferred to dead polymers, resulting in the formation of branched polymers. These branched polymers are susceptible to deterioration. Because the PVAc latex particles are produced by an emulsion polymerization technique, this provides a good process for the water-based dispersion in him coatings. The main purpose of this polymer is the him coating of sustained release dosage forms. The polymer is used as a precursor in the production of polyvinylalcohol (PVA), which cannot be prepared directly by polymerization due to the unstable, isomeric monomer of acetaldehyde. 

PVC) microspheres of 0.10-0.IS pm in diameter (Asahi Kasei Co. Ltd., Japan) was used as a pre-coat reagent and precursor of the activated carbon (Sakoda et al., 1996). Preliminary experiments revealed that thermal decomposition occurs around 300 t), and that a temperature above 700 t) is needed for the complete carbonization of the polymer latex employed. The ferric sulfate (Fe2(S04) /1H2O) was used as the catalytic precursor in order to make the carbon whiskers (Li et al. 2001a, b). 

A standard Paint Research Institute latex paint, provided by J. F. Matthews of DuPont, was the reference sample to which the biocidal latex polymers were compared. After two months both the unweathered and weathered samples showed moderate or moderate to heavy growth on the paint surface. The unweathered samples showed severe stain intensities on basswood. The weathered samples showed medium stain intensities on both. When coatings of an MMA/nBA latex blended with a MMA/nBA/8 terpolymer latex were tested, only trace growth of Aureobasidlum pullulans on the coatings was observed using pine or basswood substrates. 

Emulsion polymers (latexes) are the most commonly used film formers in the coating industry this is particularly the case with aqueous emulsion paints that are used for home decoration. These aqueous emulsion paints are applied at room temperature, when the latexes coalesce on the substrate to form a thermoplastic film. Occasionally, functional polymers are used for crossUnkirig in the coating system. The polymer particles are typically in the submicron range (0.1-0.5 pm). 

Good-rite Latexes. [BFGoodrich/Spec. Polymers] Vinyl pyridine or S/B latex used for adhesives tire cord, industrial goods dips, coatings, paper saturation. 

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