Finishes for Cellulosics

Cellulosics have certain deficiencies in properties that require finishing to improve these properties and maximize consumer usage and acceptance. The most important cellulosic finishes include crease resistant and stabilizing finishes, soil release and softening finishes (in conjunction with crease resistant finishes), oil and water repellant finishes, biologically protective finishes, and flame retardant finishes. 

---

The earliest polymeric cationic aftertreatments stemmed from the development of crease-resist finishes for cellulosic fibres. One such, promoted specifically for its colour fastness improvements when applied as an aftertreatment to direct dyeings, was a condensation product of formaldehyde with dicyandiamide (Scheme 10.82). Many similar compounds followed, such as condensation products of formaldehyde with melamine (10.212), polyethylene imine) with cyanuric chloride (10.213) and alkyl chlorides with polyethylene imine) (10.214 R = alkyl). 

Table I. Weather-Resistant Finishes for Cellulosic Fabrics...

Table 8.3 Comparison of two permanent flame-retardant finishes for cellulosics...

Usable for anti-pilling Hand building finishes, for cellulosics easy-care Durable press finishes Cellulase finishes... 

A permanent flame retardant finish for cellulose fibers. PROTE-NYL BN-5724-S ... 

Formaldehyde is an important constituent of many textile finishes, especially finishes for cellulosic textiles. As the main chemical route to cross-linking cellulose, formaldehyde or a reactant made from formaldehyde is found in a variety of finishes, ranging from durable press agents to water repellents. 

Orcoset [Cyanic Dyestuffs] Pcdyvinyl acetate emulsion semidutable hand building finish for cellulosics and synthetics. 

Textile Fibers, Dyes, Finishes, andProcesses FIN1SHF.S APPT.mn TO FIBER CLASSES Finishes for Cellulosics... 

Non-drying oil resins are soluble only in Aromatic hydrocarbons. They are used with amino resins for stoving finishes for appliances. Medium resins are used as plasticisers for cellulose nitrate. Along with natural oils several natural occurring and synthetic acid like resin (abiotic acid) pelargonic acid and isooctanoic acid are added to modify alkye resins. The alkyd resins are obtained by two processes, i.e., (1) Fatty Acid Process and (2) Alcoholysis process. 

The electrophoresis is run at 1000 V cvfor 30-45 min. After finishing, the cellulose sheet is dried in a stream of warm air. For visual detection of amino acids the cellulose sheet is sprayed with Soln. B and incubated in a drying oven at 110-120 °C until blue spots appear. Autoradiography or a Phospholmager detects P-labled amino acids. 

Early Durable Finishes. Early studies lo produce durable flame retardants for cellulose were based on treatment wilh inorganic compounds containing antimony and titanium. 

The CAV for a particular process is dependent on fibre type and fabric construction and absorbency. A finish application below the CAV may result in a non-uniform speckled treatment, while an application above the CAV could lead to finish migration. Cellulosic fibres, becanse of their inherent hydrophilicity, have CAVs in the range of 35 0 % wet pickup. Hydrophobic fibres like polyester can have CAVs of less than 5 %, allowing much lower wet pickups than hydrophilic fibres. 

Another category of durable hand builders are formaldehyde-containing thermosetting polymers. These products are usually supplied as dispersions or aqueous solutions of precondensates of urea or melamine with formaldehyde, for example di-methylol urea or di- to hexa-methylol melamine and their methyl ethers. The thermosetting polymers are comparatively inexpensive and provide fabrics with stiffness and resilience. However, they have a tendency to reduce abrasion resistance, yellow after exposure to heat, and release formaldehyde. Melamine-based hand builders are more highly crosslinked than urea-based products and are accordingly more durable. Butylated urea condensates are especially useful for rayon fabrics (see also Chapter 5 Easy-care and durable press finishes of cellulosics). 

Although inorganic salts can provide excellent flame-retardant properties for cellulose, reasonable laundering durability must be incorporated into any finish destined for apparel use. The most successful durable flame retardants for cellulose are based on phosphorous- and nitrogen-containing chemical systems that can react with the fibre or form crosslinked structures on the fibre. The key ingredient of one of these finishes is tetrakis(hydroxymethyl)phosphonium chloride (THPC), made from phosphine, formaldehyde and hydrochloric acid (Fig. 8.11). THPC reacts with urea to form an insoluble structure on cellulose in a pad-dry-cure process (Fig. 8.12). 

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. 

STANDAFIN U-17 is an all-purpose softener and finishing agent for cellulosics, synthetics or blends of synthetics. 

Buffered organic/inorganic metallic blend. General purpose catalyst with minimal effect on physical properties. Will not contribute to odor development and does not discolor finished polyester/cellulose or all-cotton fabrics. Excellent agent for carbamate reactants. 

Handbuilders for cellulosic and synthetic/cellulosic blends WARCOSET CHB polymer does not contain formaldehyde. When used with low formaldehyde resins it does provide a resilient finish on rayon and polyester/rayon blends similar to that obtained with high formaldehyde resins. WARCOSET CHB solution is compatible with most commonly used finishing agents. 

---