Soil Release Finish 636k19

SOIL RELEASE FINISH A finish that increase the absorbency of a fabric, this finish allowed stains to leave the fabric faster, increase the wicking action for greater comfort in wear, makes fabric dry-cleanable with out significant loss of soil release properties, and maintains brightness after respective repeated laundering. The stain repellent is applied on the outside of the fabric to allow most water- and oil-based stains to roll off. These finishes are applied at the same time the resins are applied to the textiles. Most are durable to 40 to 50 launderings.

There are two types of soil release treatments available 1. Oleophobic treatments: Here it uses fluorocarbons which are oil repellent, soil resistant and release soil easily from the textile materials; one such compound is perfluoro-alkyl methacrylate used together with melamine formaldehyde condensate and paraffin wax. Many soil release finishes are based upon the use of organo silicon compounds which are applied by pad-dry-cure process. Thus the fabric may be padded with a mixture of methyl hydrogen polysiloxane and acetyl dimethyl benzyl ammonium chloride together with zinc acetate followed by drying and curing at 160 C for a few minutes.

2. Treatment with hydrophilic substances: Copolymers of ethyl acrylate with acrylic acid are used for soil release. Permalose T of ICI is applied (1-3%) to polyester and its blends by the pad-dry-cure process; it helps soil removal, prevents redeposition of soil during washing and prevents accumulation of static charges thereby reducing attraction of dust from the air. The finish is fast to washing and dry cleaning.

FINISHING AGENTS USED • FLUOROCARBONS • FLUOROCHEMICALS • PYRIDINUM COMPOUNDS • RESINS • SILICONE • TRIAZINE COMPOUNDS • WAX AND ITS DERIVATIVES

CLASSIFICATION OF SOIL RELEASE Carboxy-based finishes The composition of this finish is based on acrylic and methacrylic acid and ester copolymers. An ester to acid ratio of 70:30 is typical. This ratio seems to provide the proper blend of hydrophilicity and oleophobicity (hydrophilic-lipophilic balance, HLB) required for a soil release finish. The HLB scale is often used or the pre-selection of surfactants and ranges from about 0 (very hydrophobic) to nearly 20(very hydrophilic.Greater hydropilicity would strongly reduce durability to laundering. The ease of incorporating different acrylic monomers into copolymers has led to a wide variety of available finishes.other carboxy polymers that have been used as soil-release finishes include styrene-maleic anhydride copolymers and sodium carboxymethyl cellulose. Hydroxy-based finishes One of the earliest soil-release materials was starch, which functioned as a sacrifial treatment. Other starch- and cellulose based products that have been used as soil release agents include methyl cellulose, ethyl cellulose, hydroxypropyl starch, hydroxyethyl cellulose, hydroxypropylmethyl cellulose and hydrolyzed cellulose acetates. With some expectations these finished lack the laundering durability desired in finish expected to last of a garment and must be applied in combination with a binder or cross-linking agent. Ethoxy-based finishes One important group of soil-release agents for polyester fibers is based on condensation copolymers of terephthalic acid with ethylene glycol and polyethylene glycol. The structure of this polyester –ether copolymer contains blocks of polyethylene terephthalate and polyxyethylene terephthalate that provide a structure that has regions of hydrophilicity interspersed with hydrophobic regions that have a strong attraction for the polyester surface. These products can provide extremely durable soil-release properties for polyester fabrics by either exhaust or pad applications with about 0.5% solids add-on. It is possible to exhaust apply these products during the dyeing process. A modification of the condensation copolymer compounds involves incorporating anionic character into the polymer chain by use of sulfonated monomers. High soil-release performance, excellent softness and combinability with fluorocarbon finishes may be achieved by special silicone/polyalkylene oxide copolymers. Fluorine-based finishes These unique polymers have the unusual property of being hydrophobic and oleophobhic in air and hydrophilic and oil-releasing during laundering process. This is called ‘dual-action’ mechanism. The hydrophilic blocks are shielded by the fluorocarbon segments when dry, presenting a repellent surface. After immersion in the wash bath, the hydrophilic blocks can swell and actually reverse the interfacial characteristics of the surface, yielding the hydrophilic

surface necessary for oily soil release. Typically, these modified fluoropolymers are pad applied to fabrics in combination with the durable press crosslinking agents to increase the durability of the finish. The higher cost of the fluorochemical soil release agents compared to the acrylic copolymers is somewhat compensated by the low add-on required for soil-release performance. Mixtures of both polymers types provide a common compromise between efficiency and costs.

MECHANISM COMMONLY USED IN INDUSTRY 1. USE OF FLUOROCARBONS A durable stain resistant and soil release finish. This finish imparts a fabric protector that enables the fabric to repel spills and stains on . The stain resistant finishes apply a coating to the fibers. This treatment gives fabric a stiffer hand as well as some other performance problems. The fluorocarbon stain resistant finish penetrates the individual fiber, becoming the part of the fiber. The surface properties of the fabric are not altered. Liquids can be blotted and soils wiped off and soils released during laundering. 2. NANOTECHNOLOGY Nanotechnological processes for making stain-resistant fabric. It involves a chemical treatment of the fabric to create a surface that repels water and also repels oil. It prevents liquids from getting sucked up. Using nanotechnology, unique and permanent stain resistant finishes are being developed. Nanosize particles can exhibit unexpected properties— different from those of the bulk material. The basic premise is that properties can dramatically change when a substance’s size is reduced to the nanometer range. It uses chemistry to make little tiny whiskers and other things that help to repel liquids. First the fabric is treated with some acid and some hydrophobic polymers are pressed into the fabric. The fabric is then baked to make the whiskers. Supposedly, little tiny whiskers of which about one-thousand can fit across a thread of fabric. The whiskers make the fabric hydrophobic. So, it is part of the fabric and makes the fabric stain repellent. Stains don’t stay and the whiskers don’t wash away either.