Color pigments requirements

With an average particle size of 2.5 to 3.5 microns, Fire-Shield L has a lower tint strength and minimizing effect on pigmentation. This reduces the amount of colored pigments required, especially when making brightly colored PVC products. 

FWWMR Finish. The abbreviation for fire, water, weather, and mildew resistance, FWWMR, has been used to describe treatment with a chlorinated organic metal oxide. Plasticizers, coloring pigments, fiUers, stabilizers, or fungicides usuaUy are added. However, hand, drape, flexibUity, and color of the fabric are more affected by this type of finish than by other flame retardants. Add-ons of up to 60% are required in many cases to obtain... 

The production of several different products requires strict batch identity and thorough cleaning of eqmpment between batches. This is a situation existing in many small color-pigment-diying plants. 

Before moving on to a description of the application ranges of dyes and pigments, it is appropriate to trace briefly the developments in understanding of the relationship between colour and chemical constitution. This subject has been reviewed most thoroughly elsewhere [30-33] and the intention here is only to outline the basic principles so that the reader can appreciate the need for such a variety of structural types of colorant. The requirements of colour and application are often in conflict and this forms a major part of the subject matter in succeeding chapters. 

The light fastness requirements of plastic colorations are met by many organic pigments but are similarly dependent on the ratio of colored pigment to titanium dioxide. The stability of the plastic used should also be taken into consideration here. 

The thermal requirements for pigments which are targeted for PETP melt extrusion are particularly severe. However, it is important to consider the individual conditions at the various stages of polymer coloration. Pigments, for instance, which are added during the so-called condensation process in a glycol dispersion prior to transesterification or condensation in the autoclave, are exposed to temperatures between 240 and 290°C for 5 to 6 hours [43]. These harsh conditions are only tolerated by very few polycyclic pigments, primarily by representatives of the quinacridone, copper phthalocyanine, naphthalenetetracarboxylic acid, and pery-lene tetracarboxylic acid series. 

High transparency makes P.Y.24 a valuable pigment for metallic finishes. It is used in relatively light shades, typically at a ratio of one part of color pigment to three parts of aluminum pigment. Thus prepared systems demonstrate excellent weatherfastness. Flavanthrone Yellow, like P.Y.108, tends to seed (Sec. 3.7.3.1). The pigment is heat stable up to 200°C and thus satisfies all possible heat stability requirements in this area. Flavanthrone Yellow is used in various industrial paints, especially in automobile O.E.M. finishes and in automotive refinishes. 

Many colored pigments are based on cadmium compounds. For instance, cadmium sulfide (CdS) and cadmium selenide (CdSe) are used as pigments when a durable, nonfading color is required. Red is produced by CdSe, and bright yellow is produced by CdS. 

Except for the expensive cobalt green, chromium oxide is the only green pigment that meets the high color stability requirements for building materials based on lime and cement [3.69]. In plastics, however, chromium oxide green is only of minor importance because of its dull tint. 

Nacreous pigments require transparent or at least translucent binders or other carriers. Formulations with other pigments have to take their transparency and color mixing rules into account. Producers specify certain product lines for specific applications on the basis of national regulations and technical considerations. They also provide handling guidelines and starting formulas. 

During liquid makeup production, color pigments (i.e., solid having identical particle size) are added to the product via a mixer. In the pilot plant, this mixer runs at 6,700 rpm and has a diameter head of 0.035 m. Full-scale production is geometrically similar and has a mixer head diameter of 0.12 m. Determine the speed of the full-scale production mixer head. What additional information is required for the motor to drive this mixer Assume that power curves are available for this mixer design, and the scale-up basis is constant power/unit volume. 

However, there are many other chemicals and additives that a producer may be required to add to the solution, including (1) a few parts per million of a tracer element for later identification of the product (2) coloring pigments for dope dyed rayon ( dope dyeing ... 

The object is the second part of our triad. Here we will discuss how materials interact with the energy from the light source. In this book we consider objects made of polymeric materials. Generally, polymers are colorless or at best weakly colored, and the aim always seems to be to cover up the undesirable color of the polymer in favor of the more desirable color selected by the designers. This requires the addition of colorants (pigments and dyes) to the polymer. The subject of colorants will be covered in depth in another chapter. However, because colorants become part of the object, we will first discuss some aspects of how they interact with light. 

To efficiently use recycled plastics in molded parts, it is beneficial to work with several recycling suppliers to obtain a resin that is as close to the color of the product as possible. The resin that most closely matches the product may cost more per pound due to special sorting necessary to obtain a special color. This resin will probably cost less to use since it will require less corrective colorant to adjust the recycled resin to match the target. Recycled resins that are farther off color will require much more pigment to overpower the colorants in the recycled resin. 

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