VOC content

The calculation according to ISO/DIS 11 890/1 gives a more logical result. VOCs are given here as a mass share in % of the ready-to-use varnish. At a VOC content 15 % (of the mass share), the determination is made by the differential approach  

Many more recently available techniques for water determination are not sufficiently common and thus are not considered. 

Water solvent stain 5% solid matter content = non-volatile parts 25% solvent 70% water share 

In this case, the VOC content refers to 11 of actual varnish. Example 3  

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Note that the initial linear phase is observed only in sites containing a single contaminant. For sites contaminated with mixtures of contaminants there is a decreasing rate of removal from the beginning of the project due to the different volatility of the components. The more volatile constituents are extracted with a higher rate from all the phases, and as a consequence the total VOC content of extracted air decreases constantly with time. This effect should be considered during the design phase. 

The formation of ethylcellulose nanoemulsions by a low-energy method for nanoparticle preparation was reported recently. The nanoemulsions were obtained in a water-polyoxyethylene 4 sorbitan monolaurate-ethylcellulose solution system by the PIC method at 25 °C [54]. The solvent chosen for the preparation of the ethylcellulose solution was ethyl acetate, which is classed as a solvent with low toxic potential (Class 3) by ICH Guidelines [78]. Oil/water (O/W) nanoemulsions were formed at oil/ surfactant (O/S) ratios between 30 70 and 70 30 and water contents above 40 wt% (Figure 6.1). Compared with other nanoemulsions prepared by the same method, the O/S ratios at which they are formed are high, that is, the amount of surfactant needed for nanoemulsion preparation is rather low [14]. For further studies, compositions with volatile organic compound (VOC) contents below 7 wt% and surfactant concentrations between 3 and 5 wt% were chosen, that is, nanoemulsions with a constant water content of 90% and O/S ratios from 50 50 to 70 30. 

To comply with environmental legislation, coatings formulators have reformulated to water-based systems, which has wide-ranging effects on the properties of their products. Reformulating with non-hazardous air pollutants solvents such as propylene-oxide-based glycol ethers helps reduce VOC content, and is the subject of this detailed paper. 6 refs. 

The aim of the European Solvents Directive is to assist Europe in reaching the reductions in VOC emissions that it has to make under the 1991 Geneva Protocol. The VOC Directive contains a solvent consumption threshold for the vehicle refinishing industry of 500kg solvent per year. To ensure that small refinish shops are covered, a product-based Directive, where the VOC content of paints used in the sector would be regulated, may be introduced. The current situation in the US regarding VOC limits on coatings used in the architectural and industrial maintenance sectors is examined. 

ThermoWood is not resistant to exterior weathering and the colour will gradually change to the grey that is characteristic of outdoor exposed wood. In addition, exposure in exterior conditions results in the formation of small cracks on the surface of uncoated wood. Unpigmented or low-build stain coatings do not protect the surface of the wood, but solvent-borne alkyds and water-borne acrylic paints have been found to exhibit better performance than on unmodified wood. VOC emissions from the heat-treated wood are lower compared to unmodified wood and the compositions of the emissions differ. The level of emissions is lower when the wood is treated at a higher temperature. Emissions of terpenes are reduced to very low levels, and the VOC content is dominated by furfural, hexanal and acetic acid (treated at 180 °C), and by acetic acid (treated at 230 °C). ThermoWood passes ecotoxicity tests. 

Latex paint formulations can be formulated without the glycols that are usually added as stabilizers but that may be toxic and contribute to the VOC content of paint (Klein, 1993). 

The most common method for the estimation of SVOC/POM content in material samples is solvent extraction of small pieces or finely ground powder of the material. The VOC content of PVC has been estimated in PVC powder which was obtained by liquid nitrogen cooling of the material before grinding (Cox, Little and Hodgson, 2001). Preferred extraction methods are PLE and SEE, since they are very efficient. The materials must be extracted and the extracts analyzed several times to be able to estimate the number of extraction cycles needed for an exhaustive extraction. 

CEN ISO 11890-2 Paints and varnishes -Determination of volatile organic compound (VOC) content. Part 2 Gas Chromatographic method. ... 

Figure 8.20 shows another type of recycle design in which a recycle loop increases the concentration of the permeable component to the point at which it can be removed by a second process, most commonly condensation [38], The feed stream entering the recycle loop contains 1 % of the permeable component as in Figures 8.16-8.19. After compression to 20 atm, the feed gas passes through a condenser at 30 °C, but the VOC content is still below the condensation concentration at this temperature. The membrane unit separates the gas into a VOC-depleted residue stream and a vapor-enriched permeate stream, which is recirculated to the front of the compressor. Because the bulk of the vapor is recirculated, the concentration of vapor in the loop increases rapidly until the pressurized gas entering the condenser exceeds the vapor dew point of 6.1 %. At... 

Three feed streams were investigated, as shown in Table 2. Feed A was generated from a gas containing 1000 ppm C5-C9 hydrocarbons, which was blended with an equal volume of VOC-free air saturated with water vapor. Feed B, containing Cj-C chloronated hydrocarbons was generated in the same way similarly for Feed C, which contained 50 ppm trichloroethylene in addition to hydrocarbons. The components and relative proportions were selected on the basis of typical VOC contents from air strippers at several installations [2]. Note there are feeds with only hydrocarbons, with only chlorocarbons, and with a mixture of the two. 

California. This is where the regulations began. The regulatory activities of the South Coast Air Quality Management District (SCAQMD) have set a pattern that many other regulatory boards have chosen to follow. The district restricts application equipment and VOC content. The VOC... 

Tier II (adopted in 2000) reduced the VOC emissions by 50 percent. Reductions were achieved by further tightening the VOC content of coatings (at times to levels lower than those stated in the Federal Control Technique Guidelines (CTG)) and increasing application transfer efficiency requirements (at times to levels more stringent than those stated in the EPA Blue Book ). 

Pigments ideally should be non-soluble solids with low oil absorption to facilitate dispersion and allow maximum pigment loading, which would also reduce the VOC content of the paint. In addition, pigments should be chemically inert, thermally stable, pure in their composition, and nontoxic. 

Figure 12.1. Typical curve of VOCs emitted from newly laid carpet as function of time (Actual values are functions of VOC content and temperature. This curve is intended only to demonstrate the shape of a typical example of carpet VOC emissions).

Source reduction measures that can be taken to reduce emissions include using coatings with lower VOC content. 

The choice is often dependent on VOC concentration of the stream being controlled, because control efficiency depends on VOC content. 

The failure of waterborne lacquers to match both the cost and performance of conventional lacquers caused users to seek alternative methods of lowering volatile organic compound (VOC) emissions. When the U.S. Environmental Protection Agency (EPA) included methylene chloride and 1,1,1-trichloroethane in a limited list of nontoxic compounds, immediate interest developed in evaluating these products as lacquer solvents. In a short time, lacquer formulas containing 1,1,1-trichloroethane appeared in the trade, and soon thereafter reports of lower VOC content lacquers attaining commercial use were heard. Some literature shows 35-46% reductions in VOC (20). 

Developed in order to offer replacements for expensive d-limonene and pine oil in microemulsion cleaners. They all have flash points above 100C and low VOC content. 

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