Process water based

Innovation process Water-based low-solvent dipping coatings have been state-of-the-art for some time as primers. In the mid 1980s the development of water-based fillers and topcoats was advanced by VW. These have become estabhshed extensively in Germany. Solvent-free powder clear coatings have been used by DaimlerCluysler (as powder slurry suspended in water) and by BMW since 1997. 

Figure 193 Full-scale coating line for industrial application. This line processes water-based coatings. (Courtesy of Brady Corporation, Milwaukee, WI)...

With the flexographic process, water-based inks can be used on paper (original aniline dye process) where adsorption forms part of the drying process. 

In comparison to paints containing organic solvents, the application of water-based paints causes considerably lower VOC concentrations in indoor air. Processing water-based systems results in TVOC concentrations of only ca. 10 % of the TVOC values caused by processing solvent-based systems (Norback et al., 1995). In this study, concentrations within the range 0.04-12.7 mg/m were measured. 

Process operations often do not involve direct use or contact with process water. Based on the manufacturing technology apphed, aqueous emissions are expected to be minimal. During the production of FPVC products, plasticizers may be exposed for up to several minutes at temperatures of 180°C. The loss of plasticizer by evaporation and degradation can be significant. 

After cleavage the reaction mass is a mixture of phenol, acetone, and a variety of other products such as cumylphenols, acetophenone, dimethyl-phenylcarbinol, a-methylstyrene, and hydroxyacetone. It may be neutralised with a sodium phenoxide solution (20) or other suitable base or ion-exchange resins. Process water may be added to facilitate removal of any inorganic salts. The product may then go through a separation and a wash stage, or go direcdy to a distillation tower. 

The flotation process is based on the exploitation of wettabiUty differences of particles to be separated. Differences of wettabiUty among soHd (mineral) particles can be natural, or can be induced by the use of chemical adsorbates. Because the largest segment of industrial appHcations is conducted in water, with air, the following discussion is confined mainly to these fluids. 

Polyelectrolytes based on ethyleneimine are also used to treat drinking water and process water, and as agents for preventing lime deposits (407) in water extraction. The binding power of PEI is utilized for the treatment of effluents (408). Biochemical reactions can be catalyzed by using the complex-forming properties of PEIs and their affinity for organic substrates (409). 

Recovery and Purification. AH processes for the recovery and refining of maleic anhydride must deal with the efficient separation of maleic anhydride from the large amount of water produced in the reaction process. Recovery systems can be separated into two general categories aqueous- and nonaqueous-based absorption systems. Solvent-based systems have a higher recovery of maleic anhydride and are more energy efficient than water-based systems. 

Some hquid defoamers are preemulsified relatives of paste defoamers. In addition to the fatty components mentioned above, kerosene [8008-20-6] or an organic cosolvent such as 2-propanol have been used to enhance stabiUty of the oil—water emulsion and the solubiUty of the defoamer s active ingredients. These cosolvents are used less frequently as concerns increase about volatile organic emissions (VOCs) from the paper machine. Additionally, the use of ultrapure mineral oil in defoamers has become commonplace. Concern about the creation of 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) in the pulping process has led to the discovery of unchlorinated precursor molecules, especially in recycled mineral oil and other organic cosolvents used in defoamer formulations (28). In 1995 the mineral oil that is used is essentially free of dibenzodioxin and dibenzofuran. In addition, owing to both the concern about these oils and the fluctuating cost of raw materials, the trend in paper machine defoamers is toward water-based defoamers (29). 

Phthalocyanine Blues. a-Copper phthalocyanine blue is a reddish species used primarily in coatings and plastics. Several varieties are marketed. The basic form, the unstable Pigment Blue 15 [147-14-8] (Cl 74160), is used in water-based paints, paints containing weak petroleum solvents, and in certain plastics, eg, PVC, that require mild processing conditions. 

The role of chemical technology in printing is also changing. Whereas a need exists for hard copy, whether for visual, legal, or historical reasons, the hard copy must meet new standards of performance, including visual and environmental. Many traditional printing processes have become unacceptable in the workplace, and are being replaced by processes that are water-based, dry, desktop, or in some other ways more convenient. 

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