Light resistance

Acrylonitrile (AN), C H N, first became an important polymeric building block in the 1940s. Although it had been discovered in 1893 (1), its unique properties were not realized until the development of nitrile mbbers during World War II (see Elastomers, synthetic, nitrile rubber) and the discovery of solvents for the homopolymer with resultant fiber appHcations (see Fibers, acrylic) for textiles and carbon fibers. As a comonomer, acrylonitrile (qv) contributes hardness, rigidity, solvent and light resistance, gas impermeabiUty, and the abiUty to orient. These properties have led to many copolymer apphcation developments since 1950. 

Acetophenone can react with formaldehyde to yield light-resistant resins which are used as additives in nitrocellulose paints. It is also used as a photoinitiator, and in the pharmaceuticals, perfumery, and pesticide industries (344). It can be hydrogenated to 1-phenylethanol which is used for the production of aromatic ester fragrances (345). Technical-grade acetophenone is available at 2.29/kg perfume-grade acetophenone was 6.50/kg in October 1994. 

Binders and Resins. The choice of binder is the most important ingredient choice in the formulation process because the binder affects the performance properties of a paint more than any other single ingredient (3). The physical properties of binders required for paints include the abiHty to dry or cure under various ambient conditions, good adhesion to various substrates, abrasion resistance, washabiHty, flexibiHty, water resistance, and ultraviolet light resistance. The balance of these required properties is mosdy dependent on whether the paint is being developed for interior or exterior appHcations. 

Vinyl acetate is another monomer used in latex manufacture for architectural coatings. When copolymerized with butyl acrylate, it provides a good balance of cost and performance. The interior flat latex paint market in North America is almost completely dominated by vinyl acetate—acryHc copolymers. Vinyl acetate copolymers are typicaHy more hydrophilic than aH-acryHc polymers and do not have the same ultraviolet light resistance as acryHcs as a result. 

Pigments and Extenders. Pigments are selected for use in house paints based on thek appearance and performance quaUties. Appearance includes color and opacifying abiUty. Performance quaUties include ultraviolet light resistance, fade resistance, exterior weatherabiUty, chemical resistance, as well as particle size and shape. Toxicity profiles and safety and health related properties are also important criteria in pigment selection. 

Containers. The USPXXIII—NFXVIII Hsts container requinements such as weH-closed, tight, or light-resistant. Most containers ate light-resistant (amber) glass or plastic. The latter is break-resistant and lightweight, which reduces shipping costs and increases safety. 

Wet in % of dry Ultraviolet Light Resistance Resistance to Fungus, Rot, and Mildew Resistance to Dry Heat Continuous OF... 

Figure 7 Light resistance of low-density polyethylene upon ultraviolet irradiation. 1-normal 2-quenched.

The most commonly used stabilizers are barium, cadmium, zinc, calcium and cobalt salts of stearic acid phosphorous acid esters epoxy compounds and phenol derivatives. Using stabilizers can improve the heat and UV light resistance of the polymer blends, but these are only two aspects. The processing temperature, time, and the blending equipment also have effects on the stability of the products. The same raw materials and compositions with different blending methods resulted in products with different heat stabilities. Therefore, a thorough search for the optimal processing conditions must be done in conjunction with a search for the best composition to get the best results. 

PVC modified by TPU has improved abrasive resistance, improved impact resistance (especially at low temperatures), improved oil resistance, improved heat and UV light resistance, and improved adhesive capability with other materials. 

A drug must be kept in the container in which it was dispensed or purchased. Some drugs require special containers, such as light-resistant (brown) botdes to prevent deterioration that may occur on exposure to light. 

Compounds 3 and 4 are claimed31,32 to exhibit good solubility, while 5 is stated33 to possess excellent light-resistance, However, to date, no similar product has been able to replace CVL in the marketplace. One further example of the flexibility of the synthetic route in Scheme 3 is the preparation of compound 6,34 which is reported to show light absorption in the near infrared region and is thus suitable for recordings readable by lasers. 

If a product is light sensitive, appropriate measures to protect it must be taken. This can take the form of addition of opacifying agents to the plastic, use of aluminum foil laminations, or employing light-resistant secondary packaging. 

Tamper-resistant packaging Light-resistant container Well-closed container Tight container Hermetic container Single-unit container Single-dose container Unit-dose container Unit-of-use container Multiple-use container... 

Packaging and storage. Preserve in well-closed, light-resistant container. 

The development of semiconductor diode lasers with wavelengths shorter than those used for CD-based systems means that there is a need for dyes which can exploit these wavelengths (635-650 nm) to obtain higher-density data storage, as in DVD media. Azo metal-chelate dyes can have absorption maxima in the appropriate region, and, coupled with their excellent light resistance and durability, are possible candidates for use in this respect. However, their recording and readability characteristics need to be improved. 

Ultraviolet light will convert the E-form of triprolidine hydrochloride to the Z-form. After 2 years at 37°C, triprolidine hydrochloride in a syrup formulation does not decompose more than 10%. After 3 years at 37°C triprolidine hydrochloride in tablet formulations does not decompose more than 10%. The formulations are kept in light resistant containers since triprolidine hydrochloride discolors on exposure to light.9... 

Various imidazotriazoles are used as colorant compositions showing good particle dispersion stability and color picture light resistance <2003JAP192978>. 

Substances to be stored in well-closed, light-resistant containers e.g., isoniazid, nalidixic acid, nandrolone phenylpropionate, nitrofurazone. 

In the absence of stability information that is applicable to a specific drug and preparation, the following maximum beyond-use dates are recommended for nonsterile compounded drug precautions that are packaged in tight, light-resistant containers and stored at controlled room temperature unless otherwise indicated. ... 

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