Additives transparent resins

The acrylate resinoids are esters of acrylic and methacrylic acid. Methyl methacrylate, CH2 = C(CH3)COOH3, is a liquid ester which polymerizes to a transparent resin of high tensile strength. The polymerization is brought about by catalysts such as peroxides and heat. The polymerization is assumed to take place by addition to form linear molecules ... 

Table 6.10 shows the general properties of transparent ABS. Since the characteristics differ according to the makers and the grades, only the most representative properties are listed. In addition, to show how the properties of the present transparent ABS are different from those of other transparent resins, the properties of the different kinds of transparent resins are also described. 

It exhibits distinctive physical properties, such as adhesive ability, the capacity to form fibers, and the capacity to form thin and biodegradable film, which is transparent and highly impermeable to oxygen [251]. Other applications of pullulan include blood plasma substitutes, food and cosmetic additives, adhesive additives, flocculants, resins, and environmental remediation agents [246, 252, 253]. 

An alternative system that enables the welding of transparent or opaque plastic materials has been developed by TWI Ltd in conjunction with CENTEX Corporation [6]. The Clearweld process utilizes organic-based near infrared absorbers as coatings on polymers or as additives to resins. 

In addition to the semicrystalline nylons, which comprise the vast majority of commercial resins, nylon is also available in an amorphous form that gives rise to transparency and improved toughness at the expense of high temperature properties and chemical stress crack resistance. Table 2 shows the properties of some different polyamide types. 

In addition to conferring transparency on these polymers, the amorphous noncrystaUizable nature of polysulfones assures minimal shrinkage during fabrication of the resins into finished parts. The absence of crystallinity also assures dimensional stabiUty during the service life of the parts where high use temperatures are encountered. Good dimensional stabiUty is important to many stmctural and engineering appHcations. 

Since acetal resins are degraded by ultra violet light, additives may be included to improve the resistance of the polymer. Carbon black is effective but as in the case of polyethylene it must be well dispersed in the polymer. The finer the particle size the better the ultra violet stability of the polymer but the poorer the heat stability. About 1.5% is generally recommended. For white compounds and those with pastel colours titanium dioxide is as good in polyacetals as most transparent ultraviolet absorbers, such as the benzophenone derivatives and other materials discussed in Chapter 7. Such ultraviolet absorbers may be used for compounds that are neither black, white nor pastel shade in colour. 

Alkanesulfonates are widely used as an internal antistatic agent for poly(vinyl chloride) (PVC). Since alkanesulfonates cause hazing of unplasticized PVC in the normally used quantities of 1.0 to 1.5 parts per hundred parts resin (phr), its main use is in the manufacture of opaque PVC-calendered film. To produce transparent unplasticized articles, the addition of alkanesulfonates should not exceed 0.3 phr. Figure 40 shows the antistatic effect of alkanesulfonates in PVC. 

A number of resinated grades are produced in order to provide higher transparency and to optimize other aspects of pigment properties in application. For reasons connected with process engineering, the resin is typically incorporated as a metal (calcium) resinate. In the past, types of P.R.57 1 additionally contained certain amounts of barium sulfate. 

Optical properties are related to both the degree of crystallinity and the actual polymer structure. Most polymers do not possess color site units, so are colorless and transparent. But, some phenolic resins and polyacetylenes are colored, translucent, or opaque. Polymers that are transparent to visible light may be colored by the addition of colorants, and some become opaque as a result of the presence of additives such as fillers, stabilizers, moisture, and gases. 

By using a COC, the softening point, melting point and dielectric property of the resultant toner can be satisfactorily controlled. Thereby the non-offset fixing temperature range of the toner can be expanded. In addition, the high speed fixability, the low-temperature fixability, and the low-pressure fixability can be also improved (54). Also, their excellent optical transparency makes these resins suitable for use in full-color toners (56). 

On evaporating the epiritous eolation of opoponax, a transparent brown resin, having a peculiar odor, is obtained. It readily fuses at 212°, and, after remaining for a short time at that temperature, becomes brittle upon cooling. It dissolves In alcohol and ether, and in the caustic alkalies. The alkaline solution is reddish, and parts with the resin, on the addition of hydrochloric acid, in yellow flocculi. Its composition, as it exists in the natural gum-resin, is as under... 

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