Silicones in Textiles
Silicone chemistry has now established itself within modern textile manufacturing. Silicones are used in both the processing and final finishing of fabrics and yarns. Applications cover three main areas
- Fluids and emulsions for thread & fabric lubrication
- Antifoams as processing aids
- Emulsions for use as textile modifiers
The use of silicones as lubricant during the yarn and thread production improves the gliding properties so that the thread breakage is minimised, the sewing properties are improved and the lustre of the sewing threads enhanced. Lubrication also improves the resistance to high temperature that might occur during the process.
Silicones are well known as antifoam agents used during the sizing and dyeing processes. They control the amount of foam generated optimising productivity, continuing to perform in difficult conditions such as high temperatures and high pH values.
They may be added directly to wet processes to knock down or prevent foam and used as formulation ingredients to achieve low-foaming textile solutions.
Typical applications can be:
- Polymerization of synthetic fibers
- Production of natural and synthetic yarns
- Fabric pre-treatment's, dyeing, colouring and finishing
As antifoams, silicones are also employed to control foam in water treatment processes.
Modified silicones are used as wetting agents to reduce the surface tension of aqueous systems: the contact time between materials and the aqueous system is reduced and the production speed increased.
Silicones are used as softeners in the aqueous phase of conventional finishing processes. As "hand modifiers" to give an excellent softness and a silky, smooth or grabby hand to fibre and textile.
The finished properties will depend on the organic groups (ex. amino), which are chemically incorporated into the backbone of the silicone polymer.
The water repellent properties of the fabric can be enhanced without interfering with the permeability of the material because the pores of fabric are not occluded. With this treatment the textile becomes more resistant to abrasion and wet stains.
Silicone finishes are employed to increase the softness of fabrics thereby enhancing their aesthetic feel and imparting a particular hand.
They can also improve other physical properties, such as tear strength, abrasion, wrinkle resistance, stretch recovery and shrinkage reduction. They can provide either water absorption or water repellency and make fabrics more comfortable and more desirable to touch, purchase and wear.