Hand Builders

Another version of finish apphcation with transfer rolls is the loop transfer system, Fig. 2.5.A loop of fabric is immersed in finish liquid and then squeezed with the fabric to be treated between squeeze rollers. The finish is transferred to the fabric at a much lower wet pickup than possible by direct immersion. These roll transfer techniques are especially useful for the backside application of finishes, for example hand builders and flame retardants, to pile fabrics (without crushing the pile). 

Hand building finishes that lose their effect after one or two launderings are considered non-durable. The two major product types of non-durable hand builders are starch derivatives and polyvinyl alcohol. Natural starch is produced commercially from potatoes, com, wheat, rice and tapioca. Its two main components are polymers of a-glucose, amylopectin and amylose, shown in Fig. 4.1. The thickening effect of starch is mainly due to the long and branched amylopectin chains. 

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). 

The same subjective and objective methods for determining the effects of softeners discussed in Chapter 3 can be applied to the assessment of hand builders. Process control of fullness is most easily accomplished by monitoring the percentage weight increase of the fabric in finishing. Standard-sized samples are cut from the fabric before and after the finish is applied. The gain in weight (g m or oz yd" ) on... 

Some potential difficulties with hand builders include ... 

All of these problems are more severe at high hand builder concentrations. Selection criteria for products that add stiffness and/or fullness include cost, ease of application, compatibility with other chemicals present in the finishing bath and, of course, the properties of the resulting finished fabrics and their degree of permanence. Hand builders provide antislip effects and can be used for antipilUng. Obviously the stiffening effect is not compatible with an elastomeric finish. 

Fixation of other finishes, for example stiffening with water-soluble hand builders Fabrics with low warp and fill densities, knitted dress fabrics, denim articles, mattress duck, awning fabrics... 

The combination of EC and antistatic finishes, achieved with selected products is important for synthetic microfibre textiles. Other common finish combinations include hand builders, flame retardant and antimicrobial agents, which generate valuable and useful multifunctional finishes. 

The polymeric film formers used as non-slip finishes are typically copolymers of vinyl, acrylic and methacrylic monomers. These materials are similar in structure to the copolymers used as hand builders (see Chapter 4, Fig. 4.3 and Fig. 4.5). 

Non-slip finishes are mostly applied by the pad-dry process, combined as needed with hand builders, repellents or cellulose crosslinkers (easy-care finish). The combination of silicic acid sols with softeners or silicone-based water repellents is crucial - their effects are contrasting. 

Improved rubbing fastness can be achieved with partially hydrolysed poly vinylacetate (PVAc/PVA) or polyvinylether and the application of pigment binders, mostly based on acrylic copolymers similar to those nsed as hand builders (Chapter 4). Application methods mostly nse pad-dry techniqnes. 

Water Resistance Fair Uses Hand builders Advantage s Economi ca1... 

Water Resistance Good Uses Hand builders Advantages Economical... 

BURCO FINISH 55 is a 55% solids polyvinyl acetate emulsion for use in textile finishing as a hand builder. 

BURCO FINISH 55 is used primarily in finishing baths for fabric stiffening. It is a very efficient and economical hand builder. It tends to produce a stiff, full leathery hand as opposed to the thin, crisp hand produced by polyvinyl alcohol and starch derivatives. Being nonionic in nature, it is highly compatible with a wide variety of resins, softeners, catalysts and other finishing bath components. 

CNC Finish 81 is a synthetic hand builder and weighter used to produce unique finishes on cotton, rayon and polyester blends. In addition to giving weight to the finished fabrics, CNC Finish 81 imparts a full smooth hand with little tendency to mark-off. 

CNC SOFT 200 S is preferably applied on a padder as a total finish or in conjunction with resins and hand builders. 

ARIDRY P represents a resinous amide water repellent that is extremely durable to dry cleaning and laundering. ARIDRY P is compatible with most textile auxiliaries that are commonly used at the plant. Many effects can be obtained with the addition of resin hand builders, etc., along with fluorochemicals. ARIDRY P is an excellent extender for the latter. 

ARIDRY SS-80 has been developed as a specialty water repellent to be used where many other hand builders and auxiliaries are used without sacrificing a high degree of water repellency. ARIDRY SS-80 is a one-package zirconium product that incorporates a blend of emulsifiers that lend an inherent uniqueness to the product. ARIDRY SS-80 can be applied to many types of fabrics but is particularly effective on rayon linings. 

Polyvinylacetate hand builder which imparts a soft, full hand to the fabric. Washfast. 

Good general purpose textile finishing hand builder. 

General purpose polyvinyl acetate hand builder. Non cross-linking. PVA protected. 

VIPLEX SR is a vinyl acetate homopolymer emulsion which is an excellent hand builder for textile water repellent finishes because it has a film of high water resistance. It also forms dilute dispersions in water which are stable to substantial concentrations of electrolytes such as borax, multivalent metallic ions and quaternary compounds which coagulate many types of vinyl acetate emulsion polymers. 

VIKON FGT is also a good hand builder for silicone water repellent finishes because it has essentially no effect on the spray rating and it is fully compatible with the silicone repellents and their catalysts. 

Chem-Firm. [Ivax Industries] Polyvinyl acetate emulsion nonreactive hand builder, bodying agent... 

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