Color plastics compounding

The attributes and properties of compounded plastics are applicable to many diverse applications. Although the focus of this chapter is the compounding of thermoplastic materials, many of the principles and comments also apply to thermoset polymers such as phenolics. The chapter will discuss compounding methods, the roles and challenges of additives, and techniques for introducing color to compounded plastics. 

Many benzofuran-2-ones find application as dyes. For example, styryl analogues based on compound 262 were developed as a polymer colorant <2000W00053597>. Compounds 263 and 264 are among several stereoisomeric compounds that are patented as dyes <2000W00024736>. Dibenzofuran 265 is a photochromic compound for use as an ink or in plastic films <2001CNP1328109>. 

Dyes are chemical compounds that impart color to plastic compounds. These dissolve in the host polymer and are therefore not present as discrete particles. Dyes are typically azo or anthraquinone compounds. 

ORIGIN/INDUSTRY SOURCES/USES found as a free base in natural waters manufacture of azo dyes intermediate in synthesis of various colors plastic films determination of nicotine (quantitative) hardener in rubber compounds reagent spray reagent for sugars detection of hydrogen cyanide and sulfate detection of blood stains lignification measurement... 

The most important costabilizers in PVC formulations used mainly in combination with mixed metal salts are alkyl-aryl-phosphites to improve early color. Epoxy compounds, for example, epoxidized fatty esters such as epoxidized soy bean oil, react directly with HCl or substitute labile chlorine atoms, for example, in the presence of zinc ions. Furthermore, the epoxidized fatty esters act as plasticizers. Polyols such as pentaerythritol or dipentaerythritol and P-diketones act as complexing agents and deactivate the negative effect of the formed zinc chloride. Hydrotalcites... 

Color concentrates are usually pellets that contain a high percentage of colorant in a compatible polymer carrier. These pellets are then let down into the base polymer in a proportion that will provide the correct final concentration of colorant to the system. Color concentrate pellets are often let down at approximately 4% of the final system and require only minimal effort and hardware beyond using precolored compounds. If the main concern is adequate mixing in the extruder, this is one of the most popular forms for coloring plastics. 

Colored Compound. Processors can huy the plastic compound already precolored. This is commonly done with specialty plastics. It is expensive and leaves the processor with inventory prohlems. 

Color concentrate n. A plastic compound that contains a high percentage of pigment, to be blended in precise amounts with the base resin or compound so that the correct final color will be achieved. The concentrate provides a clean and convenient method of obtaining accurate color shades in extruded and molded products. The term masterbatch is sometime used for color concentrate, as well as for concentrates of other additives. 

Color stability n. The constancy of the characteristics of color in a plastic compound -hue, intensity, and saturation - in its products over their service fives in their design environments. 

Extrusion coloring n. the method of adding colorants to a plastic compound by dryblending the colorant with the solid granular resin, extruding the mixture into strands, and cutting these strands into pellets for use in subsequent processing operations. 

Heat stability n. The resistance to change in color or other properties as a result of heat encountered by a plastic compound or article either during processing or in service. Such resistance may be enhanced by the incorporation of a stabilizer. 

Multifunctional concentrate n. A plastic compound that contains high percentages of at least two of such additives as colorants, stabilizers, flame retardants, lubricants, antistatic agents, anti-blocking agents, blowing agents, fillers, etc, that will be diluted in base resin to provide a tailored compound with the desired final concentrations of the additives in the extruded or molded product. 

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