Engineering plastics heat stabilizers

Brominated phosphate heated in a glass tube in air at 300°C for 30 minutes remains a water-white liquid. This was compared with commercial bromine-containing flame retardants which melt they all turn color. The excellent color stability of this brominated phosphate ester makes it suitable for the high temperature processing of engineering plastics. 

Copoly(ether ester)s consisting of short-chain crystalline segments of PBT and amorphous poly(ether ester) of poly(tetramethylene terephthalate) exhibit a two-phase structure and can be used for the production of high-impact-strength engineering plastics. These very interesting materials with their outstanding properties understandably require stabilization to heat and UV exposure [45],... 

Polyethers. Acetal Resins. These stabilized polyoxymethy-lenes were introduced dramatically by DuPont and Celanese as engineering plastics to replace non-ferrous metals. Good mechanical strength, resilience, fatigue-resistance, lubricity, abrasion-resistance, heat distortion temperature, water and solvent-resistance can approach the behavior of metals on a volume basis, while processability, color possibilities, and corrosion-resistance are superior. Major weakness is sensitivity to thermal, oxidative, and ionic degradation. 

Red iron oxide has excellent heat stability. It is usable in virtually all engineering plastics. 

Cerium sulfide pigments are produced from hydrated cerium oxide or oxalate and calcined in an oxygen-free, sulfide environment. They are silica-encapsulated to minimize water-reactivity and to improve heat stability and chemical resistance properties. Because of their low relative value-in-use, they are used primarily in engineering plastics and in particular the polyamides where high-performance organic colorant alternatives and other inorganic pigment alternatives are few. 

The excellent balances of mechanical, electrical, solvent resistance, heat resistance and dimensional stability properties combined with a relatively low price have led to the common use of this material in engineering plastics. 

Ethanox 376 is a stabilizer that provides heat stability by preventing thermo-oxidative degradation during processing and service life. It provides compatibility with resins and extraction resistance. It can be applied in polyolefins, such as polyethylene, polypropylene, polybutene-1 and other polymers such as engineering plastics, styrenes, polyurethanes, saturated and unsaturated elastomers, styrenics, rubber modified styrenics, segmented block copolymers, and PVC. 

In the polymer engineering we call compounds those intimate solid mixtures in which the technical polymer material for a specific application contains all the necessary additives -e.g. plasticizers, lubricants, impact modifiers, heat stabilizers, antioxidants, flame retardants, colorants, etc. — making the material suitable for the given task. A typical PVC compound e g. for a window profile, consists of 8 - 10 components [4],... 

Celanese Nylon. [Hoechst Celanese/ Engineering Plastics Hoechst UK] Nylon 6/6 resins, some glass-reinforced, heat-stabilized, lubricated for inj. molding and extrusion of mech. parts, gears, bearings, hardware, automotive parts, monofflaments. 

Uses Modifier for PP, PVC, polyethylene, PS, and high-performance engineering resins antioxidant heat stabilizer UV stabilizer vise, depressant emulsifier in cosmetics emollient, skin protectant, film-former in skin care chemical intermediate for oxidation, ethoxylation, sulfation, amination, esterification coemulsifier and direct additive in coatings processing aid, lubricant, dispersant in plastics food-pkg. adhesives Trade Names Unilin 700 Alcohol... 

The thermally stable plastics are correspondingly classified in two classes heat stable and high-temperature-stable plastics. The emphasis in heat stable plastics is on the resistance to mechanical deformation at higher temperatures. Such plastics can be applied at temperatures up to 250-300°C, whereas conventional plastics can only be used up to about 100°C. Many engineering plastics belong to the heat stable plastics (see also Section 36.4). Thermal dimensional stabilities of at least 180°C, tensile strengths of at least 45 MPa and flexural moduli of at least 2 200 MPa at this temperature with retention of at least 50% of the mechanical property values at 115° C in air for at least 11.5 years (100 000 h) are required of these polymers. In addition, the polymers should be resistant to as many chemicals as possible at temperatures of 80°C and higher. 

Many kinds of polymers are used in the electronics industries, from polyethylene to so-called super engineering plastics, such as polyethersulfone or polyimide. Almost all of them require additives. The reason for this is either to retain intrinsic characteristics or to extend those characteristics. In order to retain properties, polymers need process and heat stability, thermal stability or light stability. For the acquisition of new function, many kinds of functional additives can be added. Metal deactivators, antistatic agents and flame retardants are just some examples. 

Figure 6.65 Stress vs. strain at various temperatures for DSM Engineering Plastics Stanyl TE200F6—30% glass fiber reinforced, heat stabilized Nylon 46 resin.

Figure 6.67 Shear modulus vs. temperature for DSM Engineering Plastics Stanyl TE250 Series—fiber glass filled, heat stabilized, fire retardant Nylon 46 resins [5].

---