Solvent-containing paints

Table 7 shows the calculated weight percent of calcium carbonate and titanium dioxide in the white-colored paint sample. These levels are based on the calcium and titanium levels shown in Table 6. Calcium carbonate was evident by the FTIR spectrum acquired from the dried paint sample, shown in Figure 13. (Flad it been available, Raman spectroscopy, which gives ready access to the low wavenumber region, could have been used to confirm the presence (and polymorphic form) of titanium dioxide [4].) Given the white color of the paint, it is likely that the titanium present was present as titanium dioxide, and this was assumed in the calculations. The calculated weight percentage of calcium carbonate in the dried paint is 21.7 wt%, and 12.6 wt% in the paint containing the solvents. The titanium dioxide levels were calculated to be 30.6 and 17.7 wt% in the dried and solvent-containing paint sample, respectively.

Bismuth vanadate pigments are used in the manufacture of lead-free, weather resistant, brilliant yellow colors for automobile finishes and industrial paints. They are suitable for the pigmentation of solvent-containing paints, water-based paints, powder coatings, and coil-coating systems. It can be mixed with other pigments... 

Evaporation of the organic solvents from solvent-containing paints... 

All vinyl resins have a linear carbon chain with lateral substituents and exhibit a range of molecular masses. Increasing molecular mass is accompanied by improved mechanical properties, a decrease in solubility, and an increase in the viscosity of their solutions. Vinyl resins of high molecular mass can therefore only be used in the form of dispersions or powders for paint applications. Solvent-containing paints require vinyl resins of considerably lower molecular mass than plastics, since only then a sufficient binder content can be achieved in the viscosity range required for paint application. 

Saturated paint polyester resins are soluble in esters, ketones, and in some cases aromatic hydrocarbons, but are insoluble in aliphatic hydrocarbons and alcohols. Solvent-containing paints based on high molecular mass resins have solids contents of 35-50 wt% at application viscosity. Paint solids contents for low molecular mass polyesters are 50-70 wt%. 

Esters, ketones, and ether esters of polyurethane grade (i.e., absence of reactive constituents and a maximum water content of 0.05%) are required for solvent-containing paints. Aromatic hydrocarbons are suitable as diluents. High-solids two-pack paints containing 30-40 wt% of volatile components are becoming more popular on account of their low solvent emission. 

Solvent-free two-pack systems require liquid reaction components and are normally based on MDI and its homologues. In contrast to solvent-containing paints, pigmented solvent-free two-pack systems require the use of water-binding agents (e.g., zeolites) to obtain thick, bubble-free coatings. 

The high polarity of water is responsible not only for differences between the application behavior of waterborne paints and solvent-containing paints. It also means that the organic polymers used as binders for waterborne paints must have a different structure from those used in solventborne paints. 

The problem of wastewater is closely coupled with the processing of solvent-containing paints, adhesives, and other preparations. 

EP resins are an alternative that cure tack-free. Solvent-containing paints may also be suitable, if the coating layer adheres sufficiently and is resistant. However, paints contain solvents that may evaporate so that other solvents, e.g., from the UP resin laminate, can penetrate the remaining structure and subsequently diffuse out slowly and influence environment or stored goods in containers made from UP laminates. 

Solvents containing moisture-cured or two-pack polyurethane resin paints are also used extensively. They... 

These are the most important components of paint. Coatings can be either clear or opaque (containing pigments) and either solvent- or water-based. With solvent-based paints, after application, most of the solvent is lost through evaporation. These solvent-based coatings are mostly alkyds (name derived from alkyl/acid) or modified alkyd resins. Normally they contain 30% polymer solids higher solids content is limited by the increasing viscosity of the system. 

The composition of industrial wastes varies depending on the industrial structure of a country or region. It consists of general rubbish, packaging, food wastes, acids, alkalis, oils, solvents, resins, paints, mine spoils and sludges. A proportion of the industrial waste is classified as hazardous waste because it contains materials that are presently or potentially hazardous to humans and other living organisms. 

Apart from pigment preparations which have been developed specifically for aqueous emulsion paints, there are also products known as multipurpose tinting pastes that show outstanding fastness. They have the advantage of being useful not only in emulsion paints but also in solvent containing architectural paints. 

Some people find the effects of solvents on the nervous system desirable and purposely inhale (sniff) solvents to induce a form of intoxication. In the United States approximately 15% of high school students have tried solvent inhalation at least once. Solvents suitable for inhalation and abuse are common in the home. Home products that may contain solvents include paints, paint remover, varnishes, adhesives, glues, degreasing and cleaning agents, dyes, printing ink, floor and shoe polishes, waxes, pesticides, drugs, cosmetics, and fuels, just to name a few (Table 11.1). 

Volatile organic chemicals are released during a number of industrial and manufacturing operations. For example, 1,3-butadiene is an important raw material in the manufacture of synthetic rubber During manufacture small amounts of the chemical escape into the air. Formaldehyde is a raw material used in the manufacture of a variety of building materials, such as phenol-formaldehyde and melamine resins. Many household products, such as cleaning products, varnishes, waxes, paints, and organic solvents, contain VOCs, which vaporize and escape easily into the atmosphere when they are used. For this reason, VOCs often build up indoors. 

Republic Container Co. (Nitro, West Va.), a company that supplies steel drums, switched from a solvent-based paint to a water-based paint, reducing their VOC emissions to 2.8 Ib/gal and saving over 10,000 in costs. 

Dichloromethane is used principally as a solvent, in paint removers, degreasers and aerosol products, and in the manufacture of foam polymers. Widespread exposure occurs during the production and industrial use of dichloromethane and during the use of a variety of consumer products containing dichloromethane. Substantial losses to the environment lead to ubiquitous low-level exposures from ambient air and water. 

At Desoto, in Greensboro, N.C., wash solvent from each solvent-based paint batch is separately collected and stored. When the same type of paint is going to be produced, waste solvent from the previous batch is used in place of virgin solvent, reducing the volume of the wastestreams which can contain metals as well as other paint wastes and solvent. In 1981, Desoto produced 25,000 gallons of waste mineral spirits. In 1982, when the system was implemented, waste solvent production amounted to 400 gallons. This same technique is currently being applied to their latex paint production operation (Kohl 1984). 

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