Fibres heat stabilizers

UV, hydrolysis and/or heat stabilized lower cost improved colour and gloss retention cold-temperature ductility and flexibility soft touch food contact fireproofed low compression set and creep reduced oil swelling improved chemical resistance better resistance to microorganisms transparent colourable glass fibre reinforced antistatic grades... 

Research into controlled-release antimicrobials continues with organo-silver compounds and silver zeolites, which are promising candidates for textile finishes. Silver ions, for example, incorporated in glass ceramic, have a very low toxicity profile and excellent heat stability. These principles are also used for fibre modification, an alternative to the antimicrobial finishes with high permanence. In recent years a variety of antimicrobial modified fibres have been developed, including polyester, nylon, polypropylene and acrylic types. An example of these fibre modifications is the incorporation of 0.5-2 % of organic nitro compounds... 

These fibres are made from a melt-extrudable composition containing a polyolefin and an antimicrobial siloxane quaternary ammonium salt, which can be a trisiloxane having a pendant quaternary ammonium group and a molec. wt. of from about 600 to 1,700 or an ABA-type siloxane having a polydispersity of up to about 3.0 and a weight-average molec.wt. of from about 800 to 2,000 in which a central moiety is terminated at each end by a quaternary ammonium salt group. The anion can be one, which does not adversely affect the heat stability of the salt. 

The chemical composition of the fibres, their geometry and the spinning conditions define the range of properties glass transition temperature, melting point, heat stability, combustibility, specific electrical resistance, resistance to environment (humidity, chemical, biological, radiation), dye-ability, solubility and the mechanical properties which are listed in the following chapter. The main characteristics of fibres are listed below. 

Nylostab S-EED is an aromatic HALS used as a multi-functional additive in polyamides. Due to a novel chemical structure, it combines the effect of a light and heat stabilizer, resulting in flow improvement particularly in fibres, and its action in the improvement of colour strength with pigments and dyes. 

In practical terms this means that the typical engine bay requirement of survival at around I30°C for 5000 hours is too severe for an unstabilized, unreinforced version of an engineering plastic like nylon, but acceptable for glass fibre reinforced nylon (e.g., in hot air intakes), and for heat stabilized unfilled nylon (e.g., in oil filler caps, cable ties and electrical connectors). Most reinforced nylon types will withstand much higher temperatures for a limited period, but for temperatures above about I30°C to be sustained for the whole life of the engine, it is necessary to go to more expensive materials, e.g., special polyamides like nylon 46, or aromatic thermoplastics like PPS or PES, or to high performance thermosets. 

Carbon black in a suitable concentration can make the article sufficiently protected for 10 years continuous outdoor exposure in temperate climates. The use of carbon black is clearly restricted in fibres and films. In addition, the heat stability of the carbon black modified grades may be poor in comparison to unmodified grades. 

Comments GF = glass fibres, GB = glass beads, MF = mineral filler, CC = chemically coupled, HS = heat stabilized, ... 

Comments Grades 148 H, 158 K and 165 H also available. GP = general purpose, EF = easy flow, GF UV = UV stabilizer, FR = flame retardant, HS = heat stabilized. = glass fibres. ... 

Comments SI = silicate filler, CF = carbon fibres, HS = heat stabilized, GS = glass spheres, CK = chalk, Cu = copper, Br = bronze, HI = high impact. 

Comments HR = heat resistance, HS = heat stability, IG = impact grade, HI = high impact, FR = flame retardance, GF = glass fibres, GS = glass spheres, SI = silicate addition, H+MS = heat moisture stability. 

Comments S = glass spheres, G = glass fibres, K = carbon fibres, E = elastomer modified mineral fillers, H = heat stabilized. All data for material conditioned 40 hours at 23°C/50%R. which alters mechanical and physical properties. ... 

Comments GF = glass fibres, MF = mineral filler, HS = heat stabilized, HI = high impact, IM = impact modified, FR = flame retardant, HIF = high flow, MV = medium viscosity, HV = high viscosity, HF = halogen free, P-free = phosphorus-free,... 

Comments GP = general purpose HS = heat stabilized GF = glass fibre reinforced (various glass contents available). 

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