Polycarbonates heat stabilizers

P.R.149 also lends color to cast resins made from materials such as unsaturated polyester or methacrylic acid methylester, which are polymerized with peroxide catalysts. P.R.149 is equally lightfast in these media. In polycarbonate, the pigment tolerates exposure to more than 320°C. This is an asset in view of the fact that polycarbonate shows high melt viscosity and is thus processed at up to 340°C. The list of applications also includes other media, such as PUR foams and elastomers, for which P.R.149 is recommended because of its good heat stability and its coloristic properties. 

A number of plastics are condensation polymers and include polyesters and nylons that are not as highly oriented as the same materials but in fiber form. Other plastics have been developed that have outstanding heat stability, strength, and other properties that allow their wide use. These plastics include polycarbonates, polyimides, polybenzimidazoles, polysulfides, polyethers, polysulfones, and polyketones. 

A newer development in this area is the production of retortable, multilayer, blow-molded containers that incorporate polycarbonate as the tough outer layer, with EVOH or poly(vinyiidene chloride) (PVDC) as the barrier, and polypropylene (PP) as the food contact layer. The advantages of polycarbonate are its light weight, improved heat stability, and good optics compared to the polyolefins that are normally used. 

The anthraquinone dyes are based on the structure shown in Figure 4. Key properties are summarized in Table 3. Most commercial anthraquinone dyes have sufficient heat stability to be used in polycarbonate and thermoplastic polyesters. However, as indicated in Table 3, only a handful of these dyes are suitable for polyamide Figure 4. The anthraquinone resins and their blends and alloys. Even in these cases caution must ring system. applied. Polyamide materials colored with red anthraquinone... 

Chem. Descrip. Ethyl-2-cyano-3,3-diphenylacrylate CAS 5232-99-5 EINECS/ELINCS 226-029-0 Uses UV stabilizer for plastics (PS, styrene, copolymers, polycarbonate, PVC), acrylic coatings, varnishes, nitrocellulose and other lacquers, PUs, polyester gelcoats, inks, acrylic and vinyl adhesives Features Good heat stability... 

The optical properties, clarity and gloss, are also improved and biaxially oriented polystyrene and polypropylene films are used for envelope windows and overwraps. Biaxially oriented polyvinylidene chloride film is also used for food packaging in view of its good mechanical and optical properties, but for economic reasons it is only used if its low permeability to gases, especially oxygen, is required. The electrical properties are improved by biaxial orientation and the applications of polyester, polycarbonate and polypropylene films in capacitors are expected to show a rapid growth. In these electrical applications crystalline films are always annealed in order to improve the dimensional heat stability. 

Asalti s polycarbonates are colorless with good transparency other excellent features include, for example, heat stability and leworkability, in contrast to polycarbonates produced by the phosgene process. Asahi s polycarbonates are hi er quality because they are from impurities such as chlorinated compounds, which are difficult to remove from polycarbonates obtained from the phosgene process and which have a negative effect on polymer properties. 

Recently, impact modifiers have been developed for plastics other than PVC. Polybutylene and other olefinic thermoplastic elastomers, for example, are being used to enhance the processability, toughness, and heat stability of polypropylene film. Hydroxy-terminated polyethers are being used to increase the impact resistance of polystyrene. Other conunon applications are polycarbonate, polyurethane, thermoplastic polyester, epoxy, and polysulfone. 

We will therefore concentrate the discussion on birefringence brought about by orientation stresses. One measure to reduce this is to bring down these stresses as far as possible. From the material suppliers side this has been done by developing a polycarbonate grade especially for optical disc substrate production. This has an improved flowability due to a considerable reduction of the molecular weight, however to such a value that the thermal and mechanical properties still remain acceptable (9). Other necessary modifications have been an improvement of heat stability and optical purity. 

Organic yellow, Bayplast Yellow G Y-5680 (Bayer), exhibits a unique spectral curve with heat stability and light fastness. It can be used with most thermoplastics, including polycarbonate and nylon (processing temperatures up to 32()°C have been obtained). Cerdec s chrome titanate yellow is also recommended for engineering plastics, because of its above-average heat stability. 

Recent developments include systems with better colour fidelity and handling properties. Dover s Doverphos HiPure 4 and 4-HR are high-purity tris-nonylphenyl phosphite (TNPP) processing and heat stabilizers, claimed to reduce overall costs. With 0.1% residual nonyl phenol, they are FDA-approved for food-contact applications and also used in medicals, colour-critical polyolefins, and styrenic block copolymers. They are effective also in acrylics, elastomers, nylon, polycarbonate, polyurethanes, polystyrene. PVC. ABS, and PET. 

Thus poly(p-xylene carbonate) has been synthesized from potassium carbonate and p-xylene dibromide under the influence of 18-crown-6-ether. The crown ether formed a complex with the metal cation, thereby providing highly reactive unsolvated anions. Aromatic polycarbonates have been prepared and subjected to studies of their heat stability, mechanical strength, transparency, and electrical properties. Spiro o-carbonates have been synthesized and their poly-racrizability, by cationic initiation, has been assessed. 

Figure 1 Notched impact strength of polycarbonate in (a) hot, dry and (b) hot, wet climates, with and without ultra-violet stabilizing additives. Solid circles - controls squares - sheet triangles - -heat stabilized crosses - ultra-violet stabilized injection moulding grades. From Davis, A. and Sims, D. (1983) Weathering of polymers. Applied Science Publishers, London. Available from Chapman Hall, London.

The Solvent Yellow 157, being the tetra chlorinated sister, has high heat stability with a melt point of 403°C. It is mostly used in Japan and is now being introduced into the U.S. The suggested resins would include polycarbonate, PBT, PET, PMMA and R-PVC. 

Solvent Yellow 130 is known as an extremely bright yeUow with good heat stability. It is used in resins ranging from styrene to ABS, PET, polyamides and has some minor uses in polycarbonate. 

An alkyl-aryl phosphite which can be used as a color and processing stabilizer in ABS, polycarbonate, polyurethane, coatings, and PET fiber where regulatory approval for food contact is not required. It can also be used as a secondary stabilizer to improve color and heat stability in PVC. 

Polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) represents a typical blend that from its commercial introduction in the 1960s has become a major material in the automotive industry, as well as applications in business machine and electronic sectors. The blends provide the balance of properties required for these applications at an economic cost. These include low temperature ductility/impact and processability including injection moulding, extrusion and thermoforming. The commercial growth has been maintained by developments in heat stability, thermal ageing in hot wet environments and halogen free flame retardency [8]. 

Important properties of ethylene yclic olefin copolymers such as low melting point, high transparency, better optical characteristics, good heat stability, and high chemical resistance, have opened up its applications into areas like optoelectronic data transmission and data storage on a new generation of optical disks. These copolymers can effectively compete with existing acrylonitrile-butadiene-styrene polymers, polycarbonate and acrylics products. This will push polyolefins into the areas of speciality applications. 

Most of the thermoplastics used for extrusion and injection molding are used in the IBM process. Some of the resins are especially formulated for use on IBM machines. Easy flow, metal release, heat stability, and melt strength are some of the properties, which are specihcally designed into materials for IBM processing. Resins currently processed on IBM equipment include HDPE, LDPE, PS, ABS, PP, PVC, Barex, PET, TPR, polysulfones, polycarbonate, Amidel, acetal, and polyarylate. 

All three pigments have excellent heat stability, very good light fastness and are applicable in all major plastics including polycarbonate and acrylic resins. 

Introduced by GE Plastics in 1982, polyetherimide (PEI) is an amorphous thermoplastic offering outstanding high heat resistance and strength. The high heat resistance and heat stability are attributable to its imide structure. PEI also has resistance to a broad range of chemicals, and is inherently flame resistant with low smoke emission. A major component of PEI is bisphenol A, which is also produced by GE Plastics, mainly for use in polycarbonates. 

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