Process color control, plastics coloring

Definition End prod, of controlled hydrogenation of soybean monoglycerides Properties Nonionic Uses Emulsifier, emollient, stabilizer, dispersant, opacifier for cosmetics, foods, pharmaceuticals lubricating greases synthetic waxes textile lubricants antistat, lubricant, processing aid in plastics, nonwoven fibers dispersant for color cones. defoamer in food-contact paper/paperboard in food-contact textiles... 

The aimual worldwide production of carbon blacks, which iaclude a large variety of carbonaceous products, was estimated to be around six million metric tons ia 1994. More than 90% of this pigment is consumed by the mbber iadustries, ia particular, by the tire iadustry as a reinforcing agent. The rest (- 500, 000 t) is used for coloring plastics, printing inks, and paints. Particle size of carbon blacks varies from 5 to 500 p.m and can be controlled by the process conditions and feedstock (see Carbon, carbon black). 

Plasma processing technologies ate used for surface treatments and coatings for plastics, elastomers, glasses, metals, ceramics, etc. Such treatments provide better wear characteristics, thermal stability, color, controlled electrical properties, lubricity, abrasion resistance, barrier properties, adhesion promotion, wettability, blood compatibility, and controlled light transmissivity. 

Most of the carbon black used in the plastics industry is produced by the furnace black process (see Section 4.4.1). Fine furnace blacks often appear more bluish than coarse ones in incident light (full-tone tinting) but more brownish in transmitted light (transparent tinting) and in gray tints. By controlling the conditions of black manufacture, however, substantial shifts in hue can be achieved. Bluish carbon blacks are commonly preferred because of the impression of greater color depth. 

In addition to the dyeing and printing of natural and acrylic fibers, triarylmethane dyes are suitable for the coloration of other substrates such as paper, ceramics, leather, fur, anodized aluminium, waxes, polishes, soaps, plastics, drugs, and cosmetics. Several triarylmethane dyes are used as food colorants and aie manufactured under stringent processing controls. 

UREA-FORMALDEHYDE RESIN. An important class of amino resin. Urea and formaldehyde are united in a two-stage process in the presence of pyridine, ammonia, or certain alcohols with heat and control of pH to form intermediates (methylolurea, dimenthylolurea) that are mixed with fillers to produce molding powders. These are converted to thermosetting resins by further controlled heating and pressure in the presence of catalysts. These were first plastics that could be made in white, pastel, and colored products. See also Amino Acids Melamine. 

In this brief chapter we hope we have been able to establish in the reader s mind that the coloring of plastics materials is not a simple process. However, we would like the reader to know that it is also not an impossible problem. If one takes a sound scientific approach to variables analysis as it relates to color, for the most part the difficulties can be eliminated. As you have seen, there are many variables that must be contended with and these variables do not always act independent of each other. This means we need to define, understand, and control as many variables as possible. We suggest you start with the simplistic first theorem, which states The most likely reason that your new computer is not working is you don t have it plugged in (actual data from computer support companies). Start with the simple and work to the complex it save lots of time and is good, sound scientific thinking. Below are some simple questions to help you remember the basic variables that most often cause color problems. It is by no means all inclusive, for there are times when the solutions are complicated, but this is usually the exception and not the rule. 

The furnace black process is capable of producing a chemically pure, fine-particle carbon black with low volatile content, 1-2%, and pH ranging from 6 to 10, which is suitable for most plastics end uses. This process allows precise control of a carbon black s particle size and shape (or morphology), which ensures uniform color and physical properties in plastics applications (Fig. 11.1). 

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