Finish application methods PDF

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Summary

Notes about application methods to types of fabric finishes ....

Description

Pad-Dry-Cure (Pad Mangle) (Nip-Dip) (**WILL BE USED FOR OUR FUNCTIONAL FINISHES**) - Most important and widely used equipment - Not very fast, not meant for high volume of production - Used either for removal of water after washing, or excess dye liquor or for chemical finishing operations - For finishing applications there are of two or three bowl design - Mangle: allows uniform chemistry on fabric, takes away excess chemistry - Calculate wet pickup in % (50-100%, depending on the type of fabric or chemical used) - Solvent is evaporated at Drying, temperature: 100º - Bonding between chemicals in finish and polymer of fiber at Curing (aka cross-linking), temperature: 110º Advantages: - Uniformity of nip - Efficient water removal Disadvantages: - Small portion as it is not continuous

PICK UP - Noted in % based on the weight of air-dried fabric - Cotton: 60-70% - cotton/poly: 55-60% - Viscose: 74-82% - High pick up can lead to uneven finish distribution due to migration on the fabric surface -> high the wet pickup = higher the migration - Low wet pickup finishing can lead to saving chemicals applied to fabric (aka add-on) -> Too low of a pickup can lead to uneven distribution - More efficient and homogenous distribution - Optimum Pickup / Critical Add-on Value (CAV): the lowest amount of finish liquor that can be applied to a given cotton fabric without producing a non-uniform distribution of crosslinking after drying and curing - Penetration will be easy or difficult depending on chemical and fiber type KISS ROLL (aka slop padder) - One-sided application - Simplest methods of liquor application consisting a single roller rotating in the liquor - Fabric passes over the top surface of the roller, pickup depend on the degree of wetting of the roller surface and absorbency of the fabric - Rollers are also used in the application of stiffening agent on the back side ENGRAVED ROLL - The engraved roller rotates in a liquid bath, in which the cavities - Low wet pickups - Popular i mills with stable production Advantage: - Useful in large finishing plants where the same type of fabric is continually processed ie. cotton denim Disadvantage: - A specific engraved roller will always deliver the same volume of liquor per unit area of the fabric - If mass per unit area of fabrics are different then different engraved roller with diff cavity structure has to be used SPRAYING - Allows controlled quantities of finish to be sprayed through nozzles onto fabric which gives low wet pickup - Used for conditioning the fabric after over-drying

FOAM APPLICATION - Ecologically sustainable - Foam finishing uses foam which is usually a mixture of air and liquid and there is low wet pickup and decreased amounts of chemicals needed - As much as 95% of water normally used to apply finishes to fabrics replaced by air, decreasing drying costs COATING - Pass the cloth over two rollers situated several inches apart and under a blade - The knife presses on the cloth and spreads the coating preparation evenly over the surface of the material PLASMA TECH...