Resin finishing is a term that can be used for garments and fabrics that have been treated with specific resins that cross-link upon processing to provide an advantageous durable finish, dependant upon the resin used, various properties can be achieved such as crease recover, wrinkle resistance & recovery, shrink resistance and also reduced requirements for ironing or enhanced / easier to iron garments.
Varied legislation regarding residual formaldehyde content is a major factor when deciding which resin finish to use. Texchem have a few unique resin finishes that yield some of the lowest residual formaldehyde figures to meet certain criteria i.e. Oeko Tex finishing.
The most important aspect is chemical finishing, also known as resin finishing, easycare finishing or wash-and-wear finishing. Resin finishing has been able to maintain its position in the finishing of textiles based on cellulosic fibres despite various disadvantages such as strength losses, shade changes, reduced whiteness, and controversy about formaldehyde content.
The advantages of resin-finished over unfinished textiles, especially after washing, are:
• improved dimensional stability and shape retention
• less tendency to creasing
• easier to iron
• softer and smoother
• better appearance and therefore more durable
• less change in shade
• improved wet fastness of dyeings and prints
• less tendency to pilling, especially of fibre blends
• greater wash resistance of mechanically produced lustre and
embossed finishes and finishes with softeners, stiffening
agents, water-repellents and oil-repellents
The following different crosslinking processes are used in resin
finishing:
• Dry crosslinking process
• Moist crosslinking process
• Wet crosslinking process
• Postcure process
• Precure process
• Dip-dry process
Dry crosslinking process
The most important of these processes is dry crosslinking, in which the fabric is cured in a dry state. After being padded, the fabric is usually dried on the stenter and then cured in a curing apparatus, or on the stenter immediately after drying (flash-curing process).
Moist crosslinking process
In moist crosslinking, the fabric is cured in a moist, partially swollen state (about 6 –12% residual moisture).The fabric is padded with a liquor containing g a mineral-acid catalyst in addition to the crosslinker. The fabric is subsequently dried to a residual moisture content of 6 –12%. After being batched for one or two days at a temperature of 25– 35 °C, the fabric is washed, neutralized and dried.
Wet crosslinking process
In wet crosslinking, the reaction takes place when the fabric is in a wet,fully swollen state. Today this method is no longer used, even though it is much easier to carry out than moist crosslinking, because the dry crease recovery is almost the same as that of untreated cotton textiles.
Postcure process
The postcure process is another old process that has experienced a revival, beginning in the US. It belongs to the dry crosslinking methods and is the most significant permanent-press method. The fabric is treated as in standard dry crosslinking but not cured. The treated fabric is subsequently made up into garments and provided with crease lines or pleats in the steam press before being oven-cured.
Precure process
Crosslinking in the precure process is also carried out in the dry state. Another permanent-press method, it is a special case in which blended wovens of synthetic and cellulosic fibres (usually PES/CO or PES/CV with over 60% PES) are provided with permanent creases.
In the first step, the cellulosic component undergoes standard continuous resin-finishing by the dry crosslinking process. After making-up, the finished garment is shaped by heat setting the synthetic fibres at high temperature and under high pressure in special ironing presses.
Dip-dry process
The dip-dry process is a special case of the permanent-press or postcure process. The fabric is first made up into garments, which are dipped to impregnate them with the finishing liquor, centrifuged, dried, ironed and cured. This process has also experienced a revival. However, the curing step is difficult because of the seams, problems with yellowing, etc.
