Easy-care and durable press finishes

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). 

Easy-care and durable press finishes of cellulosics... 

Mechanisms of easy-care and durable press finishing... 

V,V-Dimethylol-4,5-dihydroxyethylene urea (DMDHEU) is the chemical basis of about 90 % of the easy-care and durable press finish products on the market. DMDHEU is synthesised from urea, glyoxal and formaldehyde as shown in Eig. 5.4. 

Easy-care and durable press finishes of cellulosics 59 Table 5.4 Effects of the ether modification of DMDHEU °... 

In commercial use, easy-care and durable press finishes are frequently combined with other finishes to provide additional properties such as water and oil repellency, flame retardancy, soil release and the like. Often the combination of another finish with the cellulose crosslinking finish will result in a more durable effect from the first finish. Combination with pigment printing is very common because of similar chemistry to cellulose crosslinking agents and binders and the similar application conditions. 

Repellent finishes are usually compatible with easy-care and durable press finishes and many softeners. However, most silicone products interfere with the oil repellency of fluorocarbon finishes and should generally be avoided in an oil-repellent formulation. This is a remarkable contrast to the incorporation of silicone segments in the backbone chain of fluoropolymers, which generates a special soft handle. 

Elastomeric finishes are often combined with easy-care and durable press finishes. The silicones reduce abrasion, increase tearing strength (Ehnendorf testing apparatus - ASTM D1424), and crease recovery. For equal crease resistance and durable press performance the amount of cellulose crosslinking agents can be markedly reduced in these combinations. ... 

A widely used biocide and preservation product is formaldehyde. Solutions of formaldehyde in water, called formalin, were used for disinfection and conservation, for example, of biological samples for display. Bound formaldehyde is released in small amounts from common easy-care and durable press finishes (Chapter 5). Therefore these finishes include - at least until they are washed - a small antimicrobial side effect. This can also be true for some quaternary compounds, for example wet fastness improvers and softeners. But for more effective requirements specific antimicrobial finishes are necessary. 

As an easy-care and durable-press finish, a non-formaldehyde containing product based on imidazolidinone (CHT, Tubingen), l,3-dimethyl-4,5-dihydroxyethylene urea (DMeDHEU) was used. All products can be mixed with water to any desired concentration. 

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