Solvent reformulation

Technique for Reformulating Solvent Mixtures in Epoxy Resin Coatings... 

The impact of the regulations in Table 4 is to require users and producers of VOC ketones to limit release by either reformulating to new solvent systems, to install environmental control systems which recover and recycle solvents, or reduce emissions with carbon absorption beds or incineration equipment. The use of some individual ketones will decline further, but the overall short-term use of ketones is forecast to remain stable (10). 

Because branched ketones and aromatic hydrocarbons are used for their cost/performance benefits, they became the solvents of choice for many apphcations. Numerous solvent systems had to be reformulated to comply with Rule 66. This usually meant an increase in cost, sometimes accompanied by performance degradation. Rule 66-type regulations were adopted in many other states and cities as well. Federal specifications for coatings and many other solvent-containing materials also incorporate Rule 66 requirements. 

Reformulating to reduce HAP solvents frequently means that solvent blend costs increase. The newer blends are generally not be as effective. For example, many coatings were usually formulated using ketones as the active solvents with aromatic hydrocarbons as diluents. This combination produced the most cost-effective formulations. However, when MEK, MIBK, toluene, and xylene became HAP compounds, less-effective solvents had to be used for reformulation. Esters are the most common ketone replacements, and aUphatic diluents would replace the aromatic hydrocarbons. In this situation, more strong solvent is required compared to the ketone/aromatic formulation and costs increase. The combination of reduced VOC emissions and composition constraints in the form of HAP restrictions have compHcated the formulator s task. 

These regulations are based in part on the amount of solvents in relation to the amount of soHds. Most wood stains are low soHds materials which rely on their transparency and their abiHty to penetrate and dry fast. Those characteristics themselves put great emphasis on the type of solvents that are used to formulate stains. The low soHds content of wood stains limits the scope of solvent substitution or reformulation. 

A good example of the effect of regulations on wood stains is the issue surrounding methanol (qv). Methanol is the most widely used solvent for wood stains because of its fast-drying properties, low cost, and the solubiHty of dyes in methanol. Because methanol is Hsted by the U.S. EPA as a ha2ardous air poUutant (HAP), and because of the extremely low soHds of wood stains, it is most likely that wood stains such as NGR, body stains, and sap stains will need to be reformulated before the end of the twentieth century. 

In Japan, the standard Eco Mark Product Category No. 102 Printing Ink Version 2.6 [26] sets on a voluntary basis standards for an environmentally friendly composition of printing inks. Since introduction of this standard in 1997, more than 90% of all offset inks in Japan were reformulated to inks free from aromatic compounds ( white oil ). To fulfil the above-mentioned standard, the inks should be based on vegetable oils. They should not contain more than 1 vol.% of aromatic hydrocarbons ( white oils ). Additionally, sheet-fed offset inks should not contain more than 30% of crude oil-based solvents and not more than 3% VOC. Web offset inks should contain no more than 45% crude oil solvents (which seems not really to be a progress in comparison to typical standard inks). By the way, it is expected from vegetable oil-based inks that the print products are as deinkable as conventional mineral oil-based offset inks. 

During recent years much technical effort of coating manufacturers has been directed at replacement of solvents due to toxicity or air pollution considerations. Our solvent formulation system has played a major role in these reformulation efforts. We have realized savings both from reduction in technical efforts and in raw materials costs. 

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 industries involved in the manufacture of solvents and formulations which use them have been hit hard by antipollution legislation. Many solvent users have responded to these regulations by reformulating products to reduce their content of volatile organic components, or even eliminate them completely [6], These... 

Many cosmetics manufacturers have used the lower phthalates (diethyl phthalate, dimethyl and dibutyl phthalates) for many years as solvents and diluents in perfumes. On the whole, the cosmetic industry is able to innovate guickly because cosmetic products have a relatively short life cycle this provides short to medium-term opportunities to formulate out the problem ingredients in the next version of the product. Raw materials come at different costs and to reformulate-out chemicals of concern may result in a temporary increase in material cost. However, as more companies switch to alternatives, economies of scale are realised and the price will fall. ... 

The cleaning solvent is tested for its capacity to dissolve paints. The recycled solvent will require some analyses to allow an estimation of the required amounts of different constituents that need to be added in order to reformulate the fresh solvent. 

The formulation of the method we have sketched, thus far applied with some approximations, may in principle also be applied to nonpolar solvents. However, there are practical difficulties to overcome. The mode analysis in nonpolar solvents is less developed and experimental data on the dielectric spectra are scarcer. The solution of using computed values of s(m) for the whole spectmm is expensive and computationally delicate. The best way is perhaps to develop for apolar solvents a variant of the reduction of Q(r, r, t) that we have introduced for polar solvents, which takes into account that in nonpolar solvents the interaction is dominated by nonelectrostatic terms. The reformulation of the theory has not yet been attempted, at least by our group, but in recent versions of the continuum ab initio solvation methods there are the elements to develop and test this new implementation. 

In the solvation theory a reformulation of electrostatic Equations (1.119) is expedient. The solute charge density p(r) serves as an input variable, i.e. the driving force. The target of a computation is the scalar solvent response potential [Pg.97]

As shown in ref. [20], the double harmonic procedure can be reformulated within the PCM so as to obtain the analogues of the classical expressions in terms of summations of derivatives of dipoles and polarizabilities with respect to normal coordinates but with all the properties computed in the presence of the solvent (i.e. exploiting effective properties), namely we obtain ... 

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