Wet finishing

Relative crystallinity undoubtedly influences such properties of cellulosic materials as rigidity, flexibility, plasticity and extensibility. Likewise the amount and reactivity of intercrystalline cellulose are major factors in common processing treatments such as bleaching, dyeing, pulping and wet finishing. Further refinement of measuring methods and the development of further correlations between crystallinity and fiber properties would contribute much to this important field. 

Aramid fibers, i.e. polyamide textile fibers made from aromatic amines and dicar-boxylic acid [177] are similar to polyamide and polyester fibers and are highly heat resistant and flame retardant. Aramid fibers must be heat set by steaming before wet finishing and washed before dyeing for good leveling. 

An alternative method to apply starch to paper, especially to paperboard grades, is to use a water box at the calender. Water boxes are used for wet-finishing of paper-board prior to coating application. Use of starch in the water box will increase surface strength and lessen fiber reswelling after coating application. Dilute dispersions of oxidized starch are used, frequently in conjunction with a lubricant to prevent calender roll picking. 

Other substantial benefits derive from reducing the wet pick-up in wet finishing and continuous dyeing operations. 

In conventional continuous wet finishing, a rather dilute, usually from 4 to 8% solids solution or dispersion of the chemicals Is prepared. The fabric Is then Immersed in this solution. The wet fabric Is passed through pad rollers to squeeze out the excess solution. Despite the squeezing, a cotton fabric usually retains 80 to 100% on the weight of the fabric of the finishing solution. For polyester-cotton blend fabrics, the wet pick-up Is normally 50 to 80% on the weight of the fabric. 

Wet dyed goods have been foam finished. Conventional wet finishing of such goods would lead to color bleeding into the finish bath as well as dilution of the finish bath due to transfer of water from the fabric to the bath. 

Chemical finishing can be defined as the use of chemicals to achieve a desired fabric property. Chemical finishing, also referred to as wet finishing, includes processes that change the chemical composition of the fabrics that they are applied to. In other words, an elemental analysis of a fabric treated with a chemical finish will be different from the same analysis done prior to the finishing. 

PERSISTOL F Cone, is an emulsifier-free, clrconium salt-containing paraffin wax emulsion with exceptionally high emulsion stability. It can be used as a water-repellent agent in general, but it is particularly suitable for the wet-in-wet finishing of linings. 

Imacol . [Sandoz Sandoz Prods. Ltd.] Estars or ethers low foaming lubricant for eventing creases and abrasions in wet finishing treatments of synthetics, cellulosics, blended fabrics. 

Intraquest TA. [Crompton Knowles] TetrasodiiunEDTA sequestering agent for textile scouring, bleaching, dyeing, wet finishing. 

The fabrics used in this study were prepared by the Southern Regional Lab especially for the 13 states involved in the S-163 Project. They Include 100% cotton, 100% polyester, and a 50/50 cotton/polyester blend. Fabrics are print cloth, woven construction, with a thread count of 70W x 78F, 3.5 ounce per square yard. All fabrics were wet finished and heat set. A durable press finish (DMDHEU) was applied to cotton and cotton/polyester fabrics. A water repellent fluorocarbon finish (Corpel) and an acrylic acid soil-release finish were applied to all three types of fabrics. Our preliminary findings for the AATCC spray test are reported here. 

The coating and infiltrating operations cover most of the dyeing and wet finishing processes. 

The wet finishing operations comprise flame-proofing treatment, softening or easy-care. Among them the easy-care finish is probably the most important one. 

Even if care is taken to minimize waste, there will still be waste to treat. Currently used wet finishing processes produce waste containing organic as well as inorganic compounds. The efflnents are rich in chemicals of which some are persistent or resistant to water treatment methods. Table 2.1 lists typical examples of finishing waste that resists biodegradation. Removal of these substances from wastewater is expensive and difficult to achieve. Because of this, the effiuent segregation and source reduction methods are preferred as economically attractive alternatives. 

Table 2.1 Typical substances present in wastewater from wet finishing processes...

The finishing process can be divided into two sections, wet finishing and dry finishing. Dry finishing can also be described as steam finishing. In more recent times, solvent finishing has been used for the treatment of wool knitwear materials. In relalion to the different types of yams used in manufacture each of these processing methods will be discussed. 

Figure 15.1 Smith drums used for wet finishing of wool.

Limiting the scope for yarn movements by setting the fabric. Unlike synthetics, lyocell fabrics are not thermoplastic and so cannot be set with heat. However, there are wet finishing treatments that can fix yams so that they will retain a memory of their crease-free state. Resin treatments help in this respect but caustic setting is particularly relevant for lyocell. 

Quality, economic efficiency and, more and more, ecological methods are the prerequisites for up-to-date production in the dye house. Color shade and depth must be attainable, and there should be adequate levelness and accurate fastness properties. Appropriate mechanical and chemical processing is necessary to suit customer requirements as well as to create the required fabric with hand-and-surface characteristics. Economical and ecological efficiency involves minimization of costs and maximum profitability as well as reproducible quality with minimal enviromnental damage. Therefore, process optimization is a must to fulfil all parameters and requirements for right-first-time production. Western wet-finishing costs are more and more apparent in various Asian countries as well and can be divided into the following approximate cost proportions ... 

Downstream processing advantages Wet finishing process Economieal finishing Monitoring and controlling... 

Therefore, process optimization is a must to fulfil all parameters and requirements for right-first-time produetion. Western wet-finishing eosts are more and more apparent in various Asian eountries as well, and can be divided into the following approximate eost proportions ... 

According to the method, sufficient antimicrobial agents should be incorporated into fibers or fabrics in a wet finishing process to provide prolonged usage. The... 

Often fibers in textile substrates are deficient in one or more properties, or improved properties are desired for the substrate. Textile finishing provides a method whereby deficiencies in the textile can be corrected or specific properties can be introduced. Physical finishing techniques (dry finishing processes) or chemical finishing methods (wet finishing) are used. Physical finishing is usually carried out on the yarn or formed textile substrate, whereas chemical finishes can be added to the spinning bath prior to fiber formation for man-made fibers or appl ied to individual fibers, yarns, or completed textile structures. 

The common textile wet-finishing methods, for example, dyeing, printing, and dip impregnation, are used for the finishing of nonwovens. In principle, it is the flat... 

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