Exterior-use paints

The composition of vinyl chloride copolymers without functional groups influences their solubility behavior and compatibility with other paint binders. For example, copolymers with isobutyl vinyl ether or maleate esters dissolve in aromatic hydrocarbons, whereas copolymers with vinyl acetate merely swell in these solvents. Paint films formed from vinyl chloride copolymers without functional groups are heat sealable on account of their thermoplastic character. Since the films adhere poorly to nonabsorbing substrates such as metals, they are suitable as binders for strippable coatings. On account of their good chemical resistance, vinyl chloride copolymers are also extremely suitable as binders for exterior-use paints, traffic paints, and paper and foil lacquers their lack of taste and odor means that they can be used as pasteurization-resistant coatings for can interiors. 

In conventional exterior-use paints SB dispersions have largely been replaced by styrene-acrylate dispersions, and their use is now restricted to special applications (corrosion protection primers, wood primers, mortar modification) where low film permeability to gases, water vapor, etc., and complete resistance of the polymer to hydrolysis are necessary. In order to achieve a uniform surface and thus improve printability, paper and card are coated with paper-coating colors. Carboxylated SB dispersions are used in these paints as binders. 

Styrene-acrylate copolymers are widely used as binders for interior-use paints, plasters, and exterior-use paints with a relatively high PVC. Water absorption and elasticity decrease with increasing styrene content. 

Exterior-use paints have a pigment volume concentration of 30-55%. They may be formulated with all of the aforementioned dispersions. Properties are adapted as appropriate to the substrates, climatic conditions, market circumstances, etc. The most important properties of exterior-use paints are their water and water vapor permeability (moisture balance), chalking resistance, and adhesion to the substrate. Special requirements apply in certain areas of application (e.g., COj protection on reinforced concrete, fungal and algal resistance in moist surroundings, crack bridging on cracked substrates, and alkali resistance on new mineral substrates). 

Since these components mainly occur as water-soluble salts, they lead to problems in the paint film for example, the paint film effloresces under the influence of humidity. This is important in exterior-use paints because it affects weather and corrosion resistance. 

The neurotoxic effects found in painters and coaters exposed to solvents are the subject of controversy. Some studies describe subjective symptoms such as fatigue, difficulty in concentrating, and short-term memory problems in workers employed in industrial paint and coatings application. These symptoms have not, however, been observed in painters employed in the architectural and exterior-use paints sectors who mainly use waterborne paints [12.11]. 

AH-acryHc (100%) latex emulsions are commonly recognized as the most durable paints for exterior use. Exterior grades are usuaHy copolymers of methyl methacrylate with butyl acrylate or 2-ethyIhexyl acrylate (see Acrylic ester polymers). Interior grades are based on methyl methacrylate copolymerized with butyl acrylate or ethyl acrylate. AcryHc latex emulsions are not commonly used in interior flat paints because these paints typicaHy do not require the kind of performance characteristics that acryHcs offer. However, for interior semigloss or gloss paints, aH-acryHc polymers and acryHc copolymers are used almost exclusively due to their exceUent gloss potential, adhesion characteristics, as weU as block and print resistance. 

Styrene—acrylic copolymers provide latices with good water resistance and gloss potential in both interior and exterior latex paints. However, they are typically regarded as having limited exterior durabiUty compared to all-acryhc latex emulsions that are designed for exterior use. 

So-called pure acryUc latexes are employed for maximum durabiUty as required, for example, in high performance exterior latex paints. On the other hand, interior flat wall latex paints do not need the high resistance to exterior exposure and hydrolysis. The most widely used latexes for this appHcation are vinyl acetate copolymer latexes such as vinyl acetate/butyl acrylate (2-propenoic acid butyl ester) [141-32-2] copolymers having just sufficient... 

The stabilizing of aqueous latexes succeeded by using emulsifiers (anionic, nonionic) and/or their mixture, steric stabilizators (polyvinyl alcohol (PVOH), hydroxyethyl cellulose, polyethylene glycol, new protective colloids etc.), and polymerizable surfaces active agents, in general. Vinyl acetate (VAc) emulsion homopolymers and copolymers (latexes) are widely used as binders in water-based interior and exterior architectural paints, coatings, and adhesives, since they have higher mechanical and water resistance properties than the homopolymers of both monomers [2, 4, 7]. 

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. 

Serious problems are encountered in the exterior use of wood due to the influence of moisture, ultraviolet light, fungi, and erosion. New, improved, exterior finishes such as silicone-modified alkyds, polymers of vinyl fluoride, and acrylic and related polymer latex paints are continually being introduced. 

Water-based decorative wall paint Low-viscosity solvent-free epoxy sealer 42 100 38 15 min 2 h 16 h Flat, decorative finish on walls and ceilings, for interior and exterior use Excellent penetrating sealer and adhesion promoter for concrete and prior to application of coatings, excellent chemical resistance... 

The type and method of a field test will depend upon the environment to which the material is to be exposed. It may not be the metal itself which is under test but the degree of protection afforded by a paint film or other protective. Reliable information is required in the shortest time and thus tests may be made more severe. A standard method of testing paint films for exterior use is to paint metal panels, some of which are scratched after... 

Use Alkyd resins are used as vehicles in exterior house paints, marine paints, and baking enamels. Molded alkyd resins are used for electrical components, distributor caps, encapsulation, and a variety of similar applications. 

Industrial and occupational exposures continue to occur (Bluhm et al. 1992 O Carroll et al. 1995). The journal Science reported the death of a prominent research chemist from mercury poisoning in a laboratory (Holden 1997). Other exposures can result from interior and exterior latex paints, many of which contained mercury-based antibacterials until 1990 and 1991, respectively (Agocs and Clarkson 1995). These paints raise household air mercury concentration 1,000-fold (Agocs and Clarkson 1995). Thermometers still use mercury, and children of thermometer plant workers have mercury levels five times those of other children in the same community (Hudson et al. 1987). 

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