BTMA - British Textile Machinery Association

Web Processing has supplied more than 900 machines to clients in 53 countries for coating, laminating, flocking and the prepregging of composites.

The company's machines are all custom-designed and built for the processing of textiles and high added-value, low-volume paper, film, foam and foils. Web Processing has laboratory facilities in place which allow 75% of the applications for which it supplies production machines to be replicated, and access agreements with certain existing clients for bulk trials in a number of the relevant application fields.

Coating

All the usual coating techniques are catered for, including blade over roller and blade over air, reverse roll, gravure, slot die, rotary screen, Meyer bar etc., and machines can be supplied in widths ranging from 25mm to 5.5 metres.

While solvent-based coatings were the norm in the early days, these were subsequently partially replaced by water-based or hot melt 100% solids resin systems, both of which offer huge environmental advantages and now as a consequence dominate new machinery developments.

Web Processing is, however, still one of a shrinking number of companies willing and able to supply machinery for handling solvents - complete with appropriate abatement and energy recapture systems for ensuring a plant is both legislation compliant and energy efficient.

Recent development work has brought about a commercially and technically viable process for the use of hot melt materials for tuft locking and secondary lamination of carpets and artificial grass.

Lamination

Solvent, water based or dry powders, adhesive films, thermoplastic powders, hot melts and most recently hot melt reactive moisture cured polyurethanes (PURs) are catered for by the Web Processing lamination machinery

PUR systems have again dominated with 50+ machines delivered in recent years, for reasons of cost, performance and environmental responsibility.

Each application is carefully evaluated and trials run to determine which system provides the best technical and aesthetic performance, as well as comparing the relative costs and minimisation of waste materials discharge eliminating pollution.

Electrostatic flocking

The electrostatic process has been turned from purely an art form into close to a science as a result of the latest range of electrostatic flocking machines brought to the market by Web Processing, which provide the highest-performance worldwide and are used for all the major applications in the fabric and wallpaper industries etc.

Flocked products were often of very poor quality in the past, but through significant improvements in the adhesive systems, the flock quality and the performance of the machinery from Web, very high density flock deposition is now possible with excellent consistency - as long as the variables are tightly controlled within the determined tolerances of each.

Prepregging

This relatively new technology is the precursor to composites manufacture, in which unidirectional fibre tapes (UDTs) or fabrics are combined with appropriate resin systems in accurately-controlled ratios. The final composite structures are moulded by laying up appropriate combinations of fabric and UDTs in the geometric distributions which will provide the greatest performance to the component, at the lowest weight and cost.

While early prepregging lines all employed solvent-based resins, and hence required large and highly expensive machinery, the move has been progressively towards solvent-free high-temperature systems and more recently to low-temperature curing hot melt resin systems. The latter can be combined on machinery typically one fifth the size and a tenth of the cost of the original solvent towers, with all their associated handling and safety equipment.

Further improvements in resin distribution uniformity are being achieved, first by casting the resin as a film and then applying this to both sides of the fabric or UDT. A combination of temperature and pressure is then employed to make the resins  flow into the substrate and maximise distribution uniformity.

In a recent development Web have teamed up with a leading expert in the composites industry and can offer the total package on fabric construction, resin formulation, prepregging, mould design and moulding.

Experienced personnel

Web Processing's personnel are mostly highly-knowledgeable engineers and chemists, with decades of experience in the company's range of processes.

The general approach by the company to a new project is to work with the prospective client to determine which technology and method of processing best achieves the required end-products. Discussions with client also involve appropriate raw materials suppliers and are followed by trials to confirm predictions. Once a machine is ordered, the construction is closely monitored through to completion, at which stage the buyer is requested to inspect and where possible to trial the machine prior to delivery.

Web Processing's technicians supervise installation and commissioning and the client is left with trained personnel, comprehensive manuals and usually a service contract for the regular maintenance of the machinery, and the re-training of operators if necessary.

Web Processing also develops compounds and formulations for clients, and in certain circumstances can arrange joint ventures, marketing assistance and ongoing product development.