Coated and laminated textile fabrics
Definitions, applications, and attributes of coated and laminated fabrics
Fabric surface modification is a novel technique by coating and lamination which can improve structural performances. It provides the opportunities to manufacturer the special fabrics like water-proof resistant tarpaulins, coverings, large tents and architectural uses, back coating for upholstery including auto seats, food, medical applications, parachutes, woven curtains, for heat-sensitive fabrics, automotive fabrics, disposable hospital apparel etc. the recent developments also enhanced the lamination and coating technique into state-of-art process of the future in textile field.
Raw-materials and their properties of Coated and Laminated Fabrics
A coated fabric combines the beneﬁts of the base fabric construction plus use of the appropriate polymer with which it is coated. The resulting coated fabric will have many properties which cannot be offered by either component individually, and careful consideration is necessary to select both base fabric and coating polymer. The base fabric provides the mechanical strength of the composite material and supports the layer of coating applied to it. For quality coated fabrics, quality base fabrics are essential.
- Polyester and nylon are the main ﬁbres used, because of their strength and general resistance to moisture, oils, micro-organisms and many common chemicals. Generally, polyester is more resistant to light and ultraviolet (UV) degradation than nylon while nylon is more resistant to hydrolysis. Polyester, however, has grown at the expense of nylon because of its better dimensional stability and shrink resistance, lower extensibility and generally lower cost.
- High tenacity nylon and polyester yarns are used in many coated articles for extra strength, and aramid ﬁbres are used where more specialist properties, such as high strength to weight ratio and resistance to high temperatures, are required.
- Acrylic ﬁbres are used for some applications where very high UV resistance is necessary, such as for awnings, car roofs and hoods for convertibles.
- Cotton was the ﬁrst fabric used in textile coating and it is still used in large quantities. In applications where strength is required, however, it has been replaced by nylon and polyester.
- Use of special verities of nylon and polyester, such as high tenacity (HT) and low shrinkage (LS), which are used in coating applications, such as tarpaulins and conveyor belts.
- Glass woven fabrics are used as bases for PTFE coatings for industrial uses, such as calendar belts and building structures. These applications make speciﬁc use of the glass properties of very high strength with very low elongation and excellent ﬂammability resistance.
Polytetrafluoroethylene, silicone polymethyl, polyethene, polyisoprene, polystyrene, polyvinyl alcohol, polymethyl methacrylate, polyvinyl chloride, polyacrylonitrile, amino cured epoxide, polyethene terephthalate, cellulose, poly hexamethylene adipamide.
As with both lamination and coating, the bonding mechanism is of importance. The bonding can occur through the thermoplastic qualities of the coating or laminate, whereas it is heat set, although this is not appropriate for all materials, so solvent or water-based adhesives are used. The use of adhesives is a highly technical area, as gaining a strong yet flexible bond can be a challenge.
The most important factor with both lamination and coating the bonding mechanism is of prime importance which may occur through the thermoplastic qualities of the coating or laminate, or is heat set, although this is not appropriate for all materials, so solvent or water-based adhesives are used. The use of adhesives is a highly technical area, as gaining a strong yet flexible bond can be a challenge.
Fabric preparation and fabric structure prior to coating is important, particularly for its stabilization, which may impact on the coating or laminate applied
The end product is sometimes referred to as a composite, as it is a composition of a textile and non-textile component. Many of the mechanical properties are determined by the fabric, such as tear strength, the coating largely determines the chemical properties, and the handle is often determined by both.
It is not just technical applications which utilize coating and lamination technology, the fast-paced fashion market is constantly giving the technology new challenges with the need to create innovative and visually interesting looks such as a high shine, futuristic finish, or imitation animal skin.