Paste forming grade

During the next few years PVC was steadily developed in the United States and in Germany. Both countries were producing the material commercially before World War II. In Great Britain, ICI in 1942 and the Distillers Company in 1943 also commenced pilot-plant production of PVC, a material then in demand as a rubber substitute for cable insulation. Paste-forming grades suitable for the production of leathercloth also became available soon afterwards. 

Yeast, Autolyzed, occurs in granular, powdered, flake, or paste form. It is the concentrated, nonextracted, partially soluble digest obtained from food-grade yeasts. Solubilization is accomplished by enzyme hydrolysis or autolysis of yeast cells. Food-grade salts and enzymes may be added. Yeast, Autolyzed contains both soluble and insoluble components derived from the whole yeast cell. It is composed primarily of amino acids, peptides, proteins, carbohydrates, fats, and salts. 

In Europe, char has long been used in the manufacture of high-grade wines. Formerly, bone char in paste form was used, but this has been superseded by activated carbon. ... 

These rosin-based sizes, whether paste, Hquid, or emulsions, can be used to size all grades of paper that are produced at acid pH. The latter include bleached or unbleached kraft Hnerboard and bag paper, bleached printing and writing grades, and cylinder board. In addition, polyaluminum compounds have been used in place of alum, most notably, polyaluminum chloride (48), which can reduce barium deposits where these have been a problem. The barium chloride by-product is more water-soluble than barium sulfate. Other polyaluminum compounds such as polyhydroxylated forms of alum and polyaluminum siHcosulfate have been evaluated as alum replacements. 

As in the case of biphenyl, current worldwide production figures for terphenyls are not readily obtainable, but the volume is probably around 6.8—8.2 million kg/yr. Currently, most of the terphenyl produced is converted to a partially hydrogenated form. U.S. production of terphenyls has remained steady at several thousand metric tons per year over the past decade. The 1991 small lot price for mixed terphenyls was about 3.89/kg whereas the specially fractionated heat-transfer-grade terphenyl—quaterphenyl mixture sold as Therminol 75 heat-transfer fluid was priced around 6.93/kg. Partially hydrogenated mixed terphenyls were priced in the 6.05—7.48/kg range depending on quantity and grade. 

Limits on emissions are both subjective and objective. Subjective limits are based on the visual appearance or smell of an emission. Objective limits are based on physical or chemical measurement of the emission. The most common form of subjective limit is that which regulates the optical density of a stack plume, measured by comparison with a Ringelmann chart (Fig. 25-1). This form of chart has been in use for over 90 years and is widely accepted for grading the blackness of black or gray smoke emissions. Within the past four decades, it has been used as the basis for "equivalent opacity" regulations for grading the optical density of emissions of colors other than black or gray. 

The simple aminophenols exist in three isomeric forms depending on the relative positions of the amino and hydroxyl groups around the benzene ring. At room temperature they are solid crystalline compounds. In the past the commercial-grade materials were usually impure and colored because of contamination with oxidation products, but now virtually colorless, high purity commercial grades are available. General properties are listed in Table 1. 

Mold-release additives are available in several forms powder, flake, liquid, or paste. High-bulk-density powders and pills have been introduced, and non-dusting grades are available. They may be added at the reactor stage of processing, or later by the compounder using melt-compounding extruders or mills. Powders may also be dusted on pellets (43). 

The commercial products are in most cases in the form of a paste. Standard pastes contain 27-35% mineral spirits. For waterborne applications carrier contains mixture of mineral spirits, nitroethane, and polypropylene glycol. Ink grades contain isopropyl alcohol or ink oil. Plastic grades are dispersed in plasticizer (DOP, DIDP), mineral oil or resin. 

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