Gas fading

New developments are hydroxylamines and lactones (for processing stability), which operate at an earlier stage during stabilisation. Lactone (benzofuranone) chemistry has been identified as commercially viable, and marks a revolutionary advance in comparison to hindered phenols and phosphites [18]. New lactone chemistry (Figure 10.1) provides enhanced additive compatibility, reduced taste and odour (organoleptics), resistance to irradiation-induced oxidation, and inhibition of gas fade discoloration. The commercial introduction of fundamentally new types of stabilisers for commodity and engineering polymers is not expected in the near future. 

Test procedures established by Committee RA-33 include a test ribbon intended to characterize the ozone content of air to which fabrics are exposed. The test ribbon is dyed to the tertiary gray shade with Cl Disperse Blue 27. Committee RA-33 has also established a test ribbon for nitrogen dioxide gas fading. 

N,0, equilibrium, the color of the gas fades from brown toward colorless. 

Oxidative transformation of phenolic antioxidants by atmospheric nitrogen oxides (NO ) taking place in the polymer matrix should be mentioned. Discoloring cyclo-hexadienones (64 is an example) are formed in the process called gas fading. 

The color of cellulose acetate dyed with some disperse dyes is subject to gas fading. Treatment of the dyed material with diethanolamine or melamine can overcome the problem (3). Similarly, with cellulose triacetate, gas fading of dyes can occur. It has been stated that protection can be obtained by the application of an inhibitor (3). 

CNC ANTIFUME DF-10 is a finishing agent for cellulose acetate and was developed for the purpose of protecting the dyed fabric from atmospheric gas fading. 

This material is an economical permanent gas-fading inhibitor, self-emulsifying in nature and applied during the dyeing process. This material also exhausts readily during the dyeing process to yield a permanent gas-fading protection. 

A specially designed gas-fading inhibitor for use with narrow elasticized fabrics where the presence of stiffening resins and optical brightener may result in yellowing on storage. This product usually is applied to white fabrics. 

Gas fading inhibitor for acetate and triacetate. Applied in the dyebath. 

Gas Fading Inhibitor Complex aromatic amine Rayon, Acetate... 

Self-emulslfiable organic amine. Substantive gas fading inhibitor for acetate and triacetate yarns and fabrics. Combines durable protection with minimum of yellowing and no retarding action in dyeing. Stable at the boll. 

Anionic OBA for nylon. Lycra, and wool. Recommended for exhaust or continuous application. Produces a brillinat reddish white with excellent fastness to light and gas fading and resistance to yellowing. 

Used for polyurethane, polypropylene, polyester and polyamide fibers where it provides gas fading resistance at low load levels. In addition, the molecular structure and the relatively high molecular weight results in a high extraction resistance in demanding applications like hot water conducting polypropylene pipes. 

Solid organophosphite antioxidant that provides color stability, reduces polymer degradation, and improves gas fading performance in many resins. It may be used in polyethylene, polypropylene, polystyrene, polyesters, elastomers, PVC and thermoplastics. 

When those dyes are applied which are known to be liable to undergo gas fading, it is advisable to use an inhibitor such as Duranol Inhibitor N (4 per cent required) or Duranol Inhibitor GF (1 per cent required). Dispersed dyes tend to sublime and mark off, during ironing or pleating, on to adjacent material. Triacetate yarns, on account of their thermoplastic nature, are often used in materials where pleating will follow dyeing and, for such purposes, dyes with low volatility are recommended. 

When goods are to be post-boarded some of the disperse dyes are not sufficiently stable to the conditions in the autoclave, particularly if the steam be moist. The disperse dyes also show a tendency to sublime which can cause staining of adjacent materials. Gas fading, however, does not occur when the disperse dyes are applied to polyamides. 

Benzothiazines have been used in industry as dyes and as antioxidants of rubber and natural elastomers. They have been used widely to prepare azodye compounds with specific properties, such as water insolubility, which is useful in the dyeing of polypropylene fibers, and increased stability to gas fading.72,73 Several reports are concerned with the antioxidant properties of benzothiazines,74-77 and their use as color photography developers.78... 

Oligomeric 35a and HMW HAS 32 were reported [273] to have comparable activity in Ti02 pigmented or unpigmented PP fibres. Both 32 and 35a have excellent physical persistence and protect PP against gas fading and loss of tensile strength. 

AntifnmeT. [Sybnm] Self-emulsifiable aromatic amino compd. gas fading inhibitor for textile processing. 

CeDamine. [Eastern Color CheiiL] Gas fading inhibitois for tmetile dyeing. 

Emkacide . [Emkay] Gas fading inhibitors, mildeweide, deodorant for textiles. 

Emkafume . [Emkay] Nondurable gas fading inhibitor for acetate colors. 

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