In the past, the so-called "technical textiles" were utilised only in special niche applications while they are now seen more and more in daily use. These fabrics do not only come from hi-tech materials but also from traditional textile materials that are "upgraded" during the finishing process by means of resins, polymers, auxiliary products and additives of different type and nature. By using the right mixtures of chemical products and the right application system a fabric can be made waterproof, UV resistant, stain-proof, fireproof, etc.
Surface finishing catering to the fashion market will take advantage of the possibility to alter the fabric "hand", look, colour etc. Innovative and peculiar tactile and optical effect can be created.
In order to achieve optimum results for the finished fabrics in terms of both aesthetic appearance and technical quality, the layer of the chemical product must be applied as evenly as possible both in regard to its quantity and spreading throughout the entire width of the treated fabric.
Application may vary according to specific needs. Sometimes the chemical product must provide a surface coating only, while in other cases it must penetrate deeply into the fabric in order to ensure different characteristics of strength and appearance depending on the performance required.
The combination of the right products and application methods allows the creation of coated textile with excellent features and specifications, lightweight, but resistant, flexible and sturdy at the same time, attractive to the eye, and with all the technical performance needed.
A multi-functional coating head is the only solution to guarantee all these application characteristics, suitable for a quick and easy use in every situation regardless of the nature of the product to be applied and the textile to be treated.
The Uniroll RBS is the multi-functional coating head that meets all these requisites: the rotating turret permits quick and easy change of the coating system according to the production necessities of the moment.
- coating by coating knife over counter-roller;
- coating by coating knife on air (floating knife);
- coating by negative engraved roller in SYNCHRO;
- coating by positive engraved roller in REVERSE;
- coating on air by positive engraved roller in REVERSE.
Being the traditional coating system by knife (doctor blade) since long widely known, it's worth spending few words on the REVERSE roll coating. This application system is still relatively unfamiliar, but it's bound to play a key role in the creation of exciting new fabrics.
ADVANTAGES OF THE REVERSE APPLICATION
- a wide range of coating coverage, from just a few g/m2 to as much as 350 g/m2 of chemical product applied without limitation due to low viscosity values;
- a perfect spreading of the applied compound, thanks to the mechanical action of the coating cylinder, which rotates in the opposite direction to fabric running. The roller engraving exerts a repeated and rapid mechanical action that ensures a perfect coating uniformity and spreading. REVERSE roller coating means breaking the compound surface tension. This technology gives excellent results with both water-based or solvent-based chemicals;
- easy dosing of the quantities of chemical compound to be applied. The quantity of chemical product applied can be increased or decreased by adjusting the rotation speed of the engraved cylinder;
- the possibility to either deposit the chemical products on the surface of the fabric or to penetrate into the fibres by decreasing or increasing the working pressure of the engraved roller. The excellent anchoring of the product to the fabric is guaranteed either way.
This type of application permits easy and precise regulation and control over the quantity of product applied in order to optimise results and ensure that the technical properties desired (waterproofing, breathability, stain resistance, flameproofing etc.) are obtained and evenly distributed throughout the width of the fabric. It removes the risks of uneven application and the insufficiency or excess of product in certain parts of the fabric's surface, and consequent irregularity in the technical characteristics required too.
The simple operation and the small quantities of chemical product required to start the coating process make the system ideal for even small production lots.