Pigments and Additives

Pigments are used to color polyurethanes, basically for appearance. Normally, cured MDI- and TDI-based polyurethanes yellow on exposure to ultraviolet light. The product will change color, becoming more yellow and 

The chemical nature of the pigment also must be considered when using it in a system that requires FDA or equivalent approval. Cadmium- and chromium-based pigments are often suspect. 

The quantity of pigment used should be kept to a minimum, normally in the range of 0.25 to a maximum of 5%. The pigmenting effect will reach a maximum and then stay relatively constant. Too much pigment will only degrade the quality of the part and add extra cost. 

Pigments can be dispensed using plastic squeeze bottles with long nozzles. If the viscosity of the material is too high, it may be diluted with some plasticizer. If larger amounts need to be used, tinting machine dispensers are an option. 

Plasticizers can perform several rolls in a polyurethane compound. There are two major groups of plasticizers used. The most common is the nonreac-tive plasticizers such as the ester group, and the second is the long-chained diols that act as a combined curative and plasticizer. In the case of the reactive material, this must be taken into account when calculating the amount of curative to be used (see Appendix 2). 

---

They may not provide superior hiding or coverage because these properties are not as important for primers as they are for topcoat paints. Primers may also contain specialty pigments and additives to help resist corrosion or prevent stain bleed-through. 

Dry-Blending. Most plasticized PVC powders are prepared by a dry-blend process in which the plasticizers, stabilizers, pigments, and additives are absorbed on the porous PVC particles at elevated temperatures while they are being agitated in a high speed mixer. Thermosetting powders are almost never prepared by this process. 

In this context, liquid specimens are polymers dissolved in solvent, in dispersion, or of very low molecular weight. The specimen may contain pigments and additives. If the specimen contains obvious colour and turbidity, then it must be prepared for complete... 

Electrolux is the world s largest producer of powered appliances for kitchen, cleaning and outdoors. They have created comprehensive Environmental Product Declarations (EPDs) for many of their product lines. Information within the product profiles details chemicals that have been banned as well as the percentage and types of materials and how they have improved material choices. Forexample, plastic components do not contain cadmium, lead, mercury or their compounds or chlorinated or brominated flame retardants metal components are not coated with cadmium, chromium, or nickel and metal paints do not contain pigments and additives based on heavy metals. Many Electrolux products are also PVC-free. 

These thermoplastic resoles and novolacs are mixed with lubricants, pigments and additives, such as wood flour. The molding compound is converted to an infusible resin by heating it under pressure in a mold. A typical sequence of chemical reactions associated with the formation of this complex, three-dimensional polymer is shown in Figure 15.4. Typical properties of phenolic plastics are shown in Table 15.4. 

To help understand the concept of anticipation, let s consider the following example. A chemist has found that a particular combination of pigments and additives results in... 

TABLE 7.1 Comparison of Pigments and Additives in the Claimed Composition and in the Prior Art References... 

Prior art reference 4 contains each and every element (and only each and every element) of the claimed composition and so appears to anticipate the later claimed invention. If we ve read carefully, however, we realize that prior art reference 4 does not describe the preparation of any of the required elements. A prior art reference cannot anticipate that which is not enabled. Is prior art reference 4 enabled Notice that the question is directed to whether the reference is enabled and not whether the reference is by itself enabled. Even though reference 4 does not enable the preparation of the required pigments and additives, those preparations are within the skill of one of... 

The term masterbatch generally refers to pelletized concentrates of pigments or additives that are embedded in a polymer matrix. They serve to ensure dust-free, accurate, and simple addition of pigments and additives to polymers and compounds. 

Both formulations are based on natural vehicles and are highly filled with pigments and additives. There are a number of differences between the two formulations but the most Important is that the samples designated BK-60 contain a linseed oil vehicle system while those designated BK-62 contain a tung oil system. Details of the ink s composition are given in Table I. 

We estimate that biotechnology will be competing with approximately 30 percent of the total chemical market by 2010 on the basis of lower cost and/or superior product features. Approximately 10 to 20 percent of basic and intermediate chemicals could be affected by production through modern fermentation. Specialties will be replaced by enzymes and natural flavors, pigments and additives. Polymers will face competition from biopolymers that are competitive in price with both polyester and nylon. 

The process of weathering Is not understood In great detail because of the complexity of paint formulations In that polymer composition, crosslinking agent, catalysts, pigments and additives all Influence the photochemical processes. 

Engelhard Corporation, Pigments and Additives Group, 101 Wood Avenue, P.O. Box... 

Pigments and Additives organic pigments for paints and dyes, ink pigments, polymer additives and flame retardants ... 

Masterbatches highly concentrated pigment and additive preparations for technical plastics, spin dying and packaging ... 

From hexahydrophthalic anhydride, aminoethanol, neopentylglycol, isoph-thalic acid, and trimellitic anhydride a carboxyl terminated poly(ester-imide) resin is made and formulated with triglycidyl isocyanurate, pigments, and additives to give a powder coating with excellent heat resistance and no chalking after 5 month at 120 °C [236]. 

Paints and coatings are based on polymers that can form a film. The polymer is considered the binder or vehicle that carries the pigments and additives that are used to impart color or protect the surface of the substrates on which the paint or coating is applied. Some examples of polymers used as paint base are copolymers of styrene-butyl acrylate or of acrylic monomer-vinyl acetate. In the product, the polymer is either finely dispersed in water forming a latex or dissolved in a solvent (in oil-based paints). Latexes for paints are usually produced by emulsion polymerization (Chapter 14). 

Organic coatings are used to block the penetration of carbon dioxide or chloride ions. They form a continuous polymeric film on the surface of the concrete, of a thickness ranging from 100 to 300 pm. The binder can already be present in the liquid paint as a polymer, or the polymer can be formed due to chemical reactions between monomeric components that are mixed just before application. Modem coating systems are usually built up of several layers applied consecutively. They are compatible with the alkalinity of the concrete and are based on various types of polymers (e. g. acrylate, polyurethane, epoxy), pigments and additives, and are made suitable for application by the addition of solvents or diluents. 

Solvents or paint thinners which carry the binder, pigments, and additives and facilitate application. These evaporate on application and are also known as reducing compounds (compounds used to reduce viscosity). 

Many binders (nitrocellulose derivatives, drying oils, and resins) are hazardous and many pigments and additives contribute hazards, but it is the host of flammable solvents and thinners used, like turpentine, naphtha, toluene. 

Chemical properties PTFE is a iinear poiymer, free from branching. PTFE requires very high processing temperatures, around 380°C, which exciudesthe use of many pigments and additives. Inorganic cadmium compounds, iron oxides and ultramarines may be used. High chemical and solvent resistance. Epoxy, nitrile-phenolic and silicone adhesives can be used. 

---