Additives, plastic

In addition to plasticizers, PVC usually incorporates other components such as impact modifiers, fillers and extenders. 

Several routes are available for synthesis of PET, starting from different monomers terephthalic acid (TPA), dimethylterephthalate (DMT) and bis-hydroxyethylterephthalate (BHET). The most common method of PET synthesis is based on the copolymerization of TPA and ethylene glycol. PET is a thermoplastic which can exist in amorphous, partially crystalline and highly crystalline states. For most PET applications, crystallinity is desired because it leads to enhanced strength and increases the maximum working temperature. 

PET is widely used in the manufacture of fibres, bottles and films. In recent years, rapid growth in the use of the moulding grades of PET has occurred. 

Thermosets are used in a similar proportion for both plastic and non-plastic applications. Plastic uses of thermosets include vehicle seats, sports equipment, electrical and electronic components, etc., while typical non-plastic applications include coatings and adhesives. 

The main commercial thermosets are urea-formaldehyde resins (UF), melamine-formaldehyde resins (MF), phenol-formaldehyde resins (PF), epoxy resins, unsaturated polyesters, alkyd resins and polyurethanes. Changes in thermoset consumption in Western Europe during the period 1994-1996 are shown in Table 1.2. UF/MF resins and polyurethanes are produced in the greatest quantities, making up about 70% of the total thermosets market. 

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R. Gachter and H. MuUer, eds. Plastics Additives Handbook, Hanser Pubhshers, Munich, Germany, 1987 H. Jenkner, "Flame Retardants for Thermoplastics, Chapt. 11 iu Gachter and Muder, pp. 535—564. 

J. Edenbaum, ed.. Plastics Additives andModifiers Handbook, Van Nostrand Reinhold, New York, 1992, Sect. II. 

H. Hiirnik, Plastics Additives Handbook, Cad Hanser Vedag, Munich, 1987, pp. 619—638. 

The Ts of methacryhc polymers may be regulated by the copolymerization of two or more monomers as illustrated in Figure 1. The approximate T value for the copolymer can be calculated from the weight fraction of each monomer type and the T (in K) of each homopolymer (15). Acrylates with low transition temperatures are frequently used as permanent plasticizers (qv) for methacrylates. Unlike plasticizer additives, once polymerized into the polymer chain, the acrylate cannot migrate, volatilize, or be extracted from the polymer. 

Plastics Additives. Many claims have been made for the use of nickel chemicals as additives to various resin systems. By far the most important appHcation is as uv-quenchers in polyolefins (173,174). Among the useful nickel complexes in these systems are dibutyldithiocarbamate nickel [13927-77-0], nickel thiobisphenolates, and nickel amide complexes of bisphenol sulfides (175). The nickel complex of... 

Organophosphoms compounds, primarily phosphonic acids, are used as sequestrants, scale inhibitors, deflocculants, or ion-control agents in oil wells, cooling-tower waters, and boiler-feed waters. Organophosphates are also used as plasticizers and flame retardants in plastics and elastomers, which accounted for 22% of PCl consumed. Phosphites, in conjunction with Hquid mixed metals, such as calcium—zinc and barium—cadmium heat stabilizers, function as antioxidants and stabilizer adjutants. In 1992, such phosphoms-based chemicals amounted to slightly more than 6% of all such plastic additives and represented 8500 t of phosphoms. Because PVC production is expected to increase, the use of phosphoms additive should increase 3% aimually through 1999. 

Poly(ethylene terephthalate). PET is a crystalline material and hence difficult to plasticize. Additionally, since PET is used as a high strength film and textile fiber, plasticization is not usually required although esters showing plasticizing properties with PVC may be used in small amounts as processing aids and external lubricants. Plasticizers have also been used to aid the injection mol ding of PET, but only at low concentrations. 

Among other mercaptocarboxyhc acids, the mercaptopropionic acids have undergone a promising development. Thiolactic acid or 2-mercaptopropionic acid [79 2-5] HSCH(CH2)COOH, is manufactured by usiag 2-chloropropionic acid [598-78-7]. 3-Mercaptopropionic acid [107-96-0] HSCH2CH2COOH, competes with thioglycohc acid ia plastic additives or as modifiers ia various polymers. Mercaptopropionic acid is... 

H. Andieas, Plastics Additives Handbook, 3id ed., Hansei Pubhsheis, New York, 1990, pp. 271—325. 

Castor Wax. Castor wax [8001-78-3] is catalyticahy hydrogenated castor bean oil. The wax has a melting point of 86°C, acid number of 2, saponification number of 179, and an iodine number of 4. Castor wax is used primarily in the formulation of cosmetics. Derivatives of castor wax are used as surfactants and plastics additives. 

In the United States approximately 50% of the 40,000 t of chloriaated paraffins consumed domestically are used in metal-working lubricants. Approximately 20% are consumed as plastic additives, mainly fire retardants, and similarly 12% in mbber. The remainder as plasticizers in paint (9%) and caulks, adhesives, and sealants at 6%. 

Plasticizers. Addition of plasticizers (qv) to polyether elastomers alters physical properties, improves processing, and can improve low temperature flexibiUty. Plasticizers also reduce vulcanizate costs by allowing the use of higher levels of less expensive fillers. 

L. Meier in R. Gachter and H. Muller, eds.. Plastics Additives Handbook, 3rd ed., Hanser PubHshers, Munich, 1990. 

Perhaps a more specialized case of using plasticizers in acrylic formulations can be found in drug delivery patches. Here, plasticizing additives called excipients... 

Addition of a plasticizer decreases the Tg of the polymer and, in partially crystalline polymers, also influences both crystallization and melting. The amount of plasticizer affects its effectiveness. Thus, while the Tg of the polymer is strongly depressed by small plasticizer additions, the increase in the plasticizer content leads to lower decrease in To and in several systems two T values can be found [36J. Therefore, the increase in the plasticizer content in polymers does not show a monotonic decrease in Tg. 

Plasticizers. Addition of softeners to NBR improve tack and adhesion properties. The most common plasticizers are esters (dibutyl phthalate, tricresyl phosphate), ester gums, alkyd resins, etc. 

PVC-.TPU Plasticizer Additives = 100 78.8 changeable value fixed value. 

Many additives are used with PVC polymers such as plasticizers, antioxidants, and impact modifiers. Heat stabilizers, which are particularly important with PVC resins, extend the useful life of the finished product. Plastic additives have been reviewed by Ainsworth. 

In addition to the broad categories of TPs and TSs, TPs can be further classified in terms of their structure, as either crystalline, amorphous, or liquid crystalline. Other classes (terms) include elastomers, copolymers, compounds, commodity resins, engineering plastics, or neat plastics. Additives, fillers, and reinforcements are other classifications that relate directly to plastics properties and performance. 

Edenbaum, J., Plastics Additives and Modifiers Handbook, Kluwer, 1992. 

Plastics additives now constitute a highly successful and essential sector of the chemical industry. Polymer additives are a growing sector of the specialty chemical industry. Some materials that have been sold for over 20 years are regarded today as commodity chemicals, particularly when patents covering their use have expired. Others, however, have a shorter life or have even disappeared almost without trace, e.g. when the production process cannot be made suitably economic, when unforeseen toxicity problems occur or when a new generation of additive renders them technically obsolete. 

There are now far more categories of additives than a few decades ago. The corresponding changes in additive technology are driven partly by the desire to produce plastics which are ever more closely specified for particular purposes. The benefits of plastics additives are not marginal. As outlined before, they are not simply optional extras but essential ingredients, which make all... 

Plastic additives are a diverse group of specialty chemicals that are either incorporated into the plastic product prior to or during processing, or applied to the surface of the product when processing has been completed. To a great extent, the selection of the appropriate additive is the responsibility of the plastic processor or the compounder carrying out the modification. Scheme 1.1 illustrates the use of typical additives in the process from polymerisation to product manufacturing. 

Plastic additives account for 15-20 wt% of the total volume of plastic products marketed. Estimates of the size of the world additives market vary considerably according to classification. Table 1.4 shows... 

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