Additional Pigments

Also, nylon-6 waste may be hydrolyzed in the presence of an aqueous alkali metal hydroxide or acid5 to produce an alkali metal or acid salt of 6-aminocaproic acid (ACA). The reaction of nylon-6 waste with dilute hydrochloric acid is rapid at 90- 100°C. The reaction mixture is poured into water to form a dilute aqueous solution of the ACA salt. Filtration is used to remove undissolved impurities such as pigments, additives, and fillers followed by treatment of the acid solution with a strong cation exchange resin. A sulfonic acid cationic exchanger absorbs ACA salt and pure ACA is eluted with ammonium hydroxide to form a dilute aqueous solution. Pure ACA is obtained by crystallization of die solution. 

Most frequently, binding protein is added to the incubation mixtures as either serum or purified serum albumin. With human serum albumin, at equilibrium, the acceptor substrate will largely be protein-bound, when the bilirubin albumin molecular ratio is smaller than one (the dissociation constant of the first binding site of purified human serum albumin is approximately 7 X 10 M with 2 X 10 M for two additional binding sites) (J2). The first binding site of albumin, measured with rat serum, has a dissociation constant of about 5 X 10" M (M8). The unbound fraction will normally not exceed the very low solubility of the pigment. Addition of albumin to an alkaline solution of bilirubin, or its addition immediately after neutralization, prevents colloid formation, if the bilirubin albumin molecular ratio is smaller than one (B25). However, colloidal bilirubin, once formed, cannot be redissolved by the addition of albumin (B26). 

The electrophilic primary and secondary quinones undergo addition of nucleophiles, including flavonoids. For instance, nucleophilic addition of catechin to its enzymatically generated quinone yielded a catechin dimer in which the catechin moieties are linked through a C6 C8 biphenyl linkage. This B-type dehydrodicatechin further oxidized to yellow pigments. Additional dehydrodicatechins arise from radical coupling of the catechin semi-quinones formed by retro-disproportionation, in which the catechin moieties are linked... 

Wet mixes are usually dried before calcination. Calcination is performed continuously in rotary or tunnel kilns, or batchwise in directly fired drum or box furnaces. The temperature at which the mixed metal oxide pigments are formed can be reduced by adding mineralizing agents [3.75]. In the case of chromium rutile pigments, addition of magnesium compounds [3.81] or lithium compounds [3.80] before calcination improves thermal stability in plastics. 

In order to remove the undesirable Texanol, ve extracted the pigment with supercritical carbon dioxide which was held at a low pressure (100 atm) for five minutes. The extract was found to contain Texanol. We increased the carbon dioxide pressure to 400 atm for five minutes to extract the pigment additive. The pressure control in SFE allows us to control the solubilizing power of the carbon dioxide, therefore, perform selective extractions. 

Silicone elastomer-based rubber compounds are prepared in conventional apparatuses (closed agitators, roll mills, etc.) and consist of the following ingredients elastomer, active fillers, vulcanising agent, stabiliser, pigment additives. 

If the scrap contains pigments, additives, or solvents, it should be handled in a manner to meet local regulation for nonfluoropolymer ingredients. Some of the mixtures may require compliance with local regulations for hazardous materials [6]. 

Although pictographs and petroglyphs have withstood hundreds, perhaps thousands of years of exposure, modem pollutants and vandalism, coupled with natural elements, have accelerated their destruction. Recently, scientists have used microscopic mineral sampling to measure the types of chemical elements found in picto-graph pigments. Additionally, studies have included the use of diversional watersheds, shelters, and application of protective adhesives to prevent rock art erosion. The continuing study of chemical compositions and rates of panel decay could one day lead to the discovery of a proper means by which to preserve these features indefinitely. 

This section does not cover the topic of coatings and finishes. These finishes are usually highly formulated and are applied as multiple-pass coatings which include special primers and intermediate layers. They may include pigments, additives, other resins, and more than one fluoropolymer. The main applications of fluoropolymer finishes are in cookware and industrial anticorrosion and high-temperature uses. A separate volume, Fluorinated Coatings and Finishes, a Plastics Design Library (PDL) volume in the Fluorine Handbook Series published by William Andrew, Inc., covers the topic. 

In the disposal of fluoropol5mer scrap containing pigments, additives, or solvents, additional consideration must be given to the regulation for the disposal of the non-fluoropolymer ingredients. Some of the compounds and mixtures may require compliance with Hazardous Material Acts. 

The typical constituents of a coating powder are binders (resins, if necessary hardeners and accelerators), colorants (mainly pigments), additives, and in some cases extenders. 

MASTERBATCH A concentrated blend of pigment, additives, fillers, and so on, in a base polymer. 

The polymer industry has long been in search of a simple, rapid analytical method to measure stabilizer content in pigment/additive concentrates. This feasibility study was undertaken to examine the accuracy, scope and limitations of the NIR technique when applied to the measurement of traditional light stabilizers in color concentrates. 

This paper will present information which is essential for the laser marking of plastics. The laser marking process and the advantages of operating a laser versus traditional methods will be discussed. The required equipment and pigment additives necessary to successfully mark plastics with lasers will be presented with samples demonstrating the effectiveness of each. 

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