Latex type

Thickeners. Thickeners are added to remover formulas to increase the viscosity which allows the remover to cling to vertical surfaces. Natural and synthetic polymers are used as thickeners. They are generally dispersed and then caused to swell by the addition of a protic solvent or by adjusting the pH of the remover. When the polymer swells, it causes the viscosity of the mixture to increase. Viscosity is controlled by the amount of thickener added. Common thickeners used in organic removers include hydroxypropylmethylceUulose [9004-65-3], hydroxypropylceUulose [9004-64-2], hydroxyethyl cellulose, and poly(acryHc acid) [9003-01-4]. Thickeners used in aqueous removers include acryHc polymers and latex-type polymers. Some thickeners are not stable in very acidic or very basic environments, so careful selection is important. 

Styrene—butadiene latexes generally are quite stable mechanically because of the presence of relatively large amounts of emulsifying and stabilizing agents, and therefore require addition of less stabilizer in compounding. The apphcations of SBR latex are classified in Table 21. This classification indicates the scope of the industry and illustrates the large number of diverse applications in which synthetic latices are employed. The latex types previously found most suitable for particular applications are also listed. 

Neoprene latex type Comonomer Emulsifiers Chlorine content, wt % pH at 25° C Standard soHds, wt % Distinguishing features Primary appHcations... 

Latex Types. Latexes are differentiated both by the nature of the coUoidal system and by the type of polymer present. Nearly aU of the coUoidal systems are similar to those used in the manufacture of dry types. That is, they are anionic and contain either a sodium or potassium salt of a rosin acid or derivative. In addition, they may also contain a strong acid soap to provide additional stabUity. Those having polymer soUds around 60% contain a very finely tuned soap system to avoid excessive emulsion viscosity during polymeri2ation (162—164). Du Pont also offers a carboxylated nonionic latex stabili2ed with poly(vinyl alcohol). This latex type is especiaUy resistant to flocculation by electrolytes, heat, and mechanical shear, surviving conditions which would easUy flocculate ionic latexes. The differences between anionic and nonionic latexes are outlined in Table 11. 

Pig. 4. Properties of various latex types. Letters designate dry types numbers indicate latex (158). 

Neoprene latexes contain 0.5 to 0.02% residual chloroprene depending on the specific latex type. The amount of free alkaH in the water phase of latexes varies from 0.1 to 0.08% depending on type and age of the material. Eye protection and appropriate skin protection have been recommended for use in situations where splashes or spills are possible. Toxicity and safe handling practices have been recommended for Du Pont types (171). Since compositions may vary with other manufacturers, specific information should be obtained for other products. 

Suspensions other than those of traditional latex type also exist. For example, particles of PVC suspended in plasticisers are widely used. After shaping, PVC pastes, as they are known, are heated to above the 7g of the PVC. At such temperatures the plasticiser diffuses into the PVC particles and this is followed... 

Water-based barrier dressings are attractive for application to injured tissue because of the biocompatibility between water and tissue. The concept of a water-based dressing initially consisted of latex-type particles of polymer suspended in an aqueous emulsion. The emulsion would be liquid applied to the tissue, water would evaporate and the particles would coalesce to form a continuous film. The rate of evaporation of water is slow compared to solvents as ethanol that was recognized to be a limitation to application time (time to place on the tissue and harden). The following description of miniemulsions (miniEP) involves a batch type... 

The selection of factors from the work [16] was done hy the significance of their effects on caoutchouc drying and after processing the opinions of eighteen researchers. The analysis included these eleven factors Xi inlet and outlet moisture ratio X2 pH value in the sixth apparatus X3 pH value in the seventh apparatus X+ NaCl consumption X5 serum consumption in the sixth apparatus X6 serum consumption in the seventh apparatus X serum temperature X8 latex type X9 fat content in caoutchouc X10 latex fat consumption on machine and Xu quantity of latex on the surface. Outcomes of the ranking of the factors are shown in Table 2.16. Determine the concordance coefficient and check its significance. 

It has been shown that tensile shear and peel strength for several latex polymers (ethylene vinyl acetate, polyvinyl alcohol, ethylene vinyl chloride, polyvinyl chloride, and acrylic) can be significantly increased by the addition of 10 percent by weight of an epoxy emulsion cured with a tertiary amine curing agent.17 The epoxy modification improves the bond strength in all cases. The degree of improvement is dependent on the selection of the latex type and the chemistry of the latex polymer. 

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... 

Algin Viscosity stabilizer for starch-dextrin and latex-type adhesives ... 

A versatile group of highly effective acrylic thickening agents for use in aqueous adhesives and latex coatings. Suitable for use with many latex types including natural rubber, S.B.R., PV acetate, PVC, Polychloroprene, acrylic and nitrile. 

Polymer alloy, containing two or more polymers in the network form, each chemically crossUnked. Sequential, simultaneous (SIN) and latex type IPNs are known. 

Differences in dispersion rheology associated with the surface energies (i.e., adsorption coverage) of the different latex types (e.g., vinyl acetate, 18 mN/m methyl methacrylate, 26 mN/m and styrene, 40 mN/m) are not realized (34). 

NW, Pigment Volume Content, and Latex. Pigment volume content (PVC) and latex type and grade are important for optimizing dry film properties. Percent NW is usually governed by the desired cost of the final product. The formulator usually does not use these variables to optimize paint rheology but should be aware of how they affect thickener efficiency. 

Latex type Ester substitute in methacrylate monomer latex/ w ... 

Polymer latex type Compressive strength, psi Tensile strength, psi... 

Latex type Size Range (nm) Eluent added species Packing types and sizes... 

In the hot-melt type, two principal polymer types are used polyolefin and ethylene co-polymer based and polyester and polyamide type. In the solvent-based type, the most prominent are neoprene (polychloroprene)-based solvent and latex types, and polyvinyl acetate emulsions. For pressure-sensitive adhesives, the most favored are acrylic adhesives and butyl rubber/polyisobutylene types. 

Progress in Organic Coatings 38, No.2, May 2000, p.89-95 INFLUENCE OF LATEX TYPE AND CONCENTRATION ON INK GLOSS DYNAMICS Desjumaux D M Bousfield D W Clatter T P ... 

Solvent-based paints (SBPs) dominated the market for construction paints until the 1970s (Hansen et al. 1987 Faassen and Borm 1991 Wieslander et al. 1997). The first water-based latex-type paint was not introduced until 1957 as an exterior paint (Rose and Vance 1997). Because of the health hazards to the peripheral and the central nervous system (Rose and Vance 1997 Wieslander et al. 1994) connected with SBPs, they have gradually been replaced by water-based paints (WBP) whenever possible (van Faassen and Borm 1991 Dias et al. 1994 Moura et al. 1994 Rietschell and Fowler 1995 Rose and Vance 1997 Wieslander et al. 1997). This has not been possible, for example, in a humid atmosphere because of the slow evaporation of water (Rose and Vance 1997). During the past 10 years, WBPs have constituted more than 90% of the construction paints in Scandinavia (Faassen and Borm 1991 Wieslander et al. 1997). In 1992, the use of SBPs among house painters was only 4% of the total paint consumption in Sweden (Wieslander et al. 1994). 

P2, P3, and P4 have OH, latex polymerization, mixed latex type (Example 7)... 

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