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Machines for coating, lamination, flocking and prepregging

During 38 years of trading, Web Processing has supplied 877 machines to clients in 52 countries for coating, laminating, flocking and prepregging for composites.

The machines are custom-designed and built for the processing of textiles and high added-value, low-volume paper, film, foam and foil products. The company has laboratory facilities allowing replication of 75% of the applications for which it supplies production machines, and access agreements with certain existing clients for bulk trials in a number of the relevant application fields.

Coating

All usual techniques are catered for, including:

blade over roller and blade over air, reverse roll, gravure, slot die, rotary screen, Meyer bar etc. and 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 systems, and hot melt 100% solids resin systems, which offer huge environmental advantages and which now in consequence dominate the much of the new machinery developments.

Web is, however, still one of a shrinking number of companies willing and able to supply machinery for handling solvents, complete with solvent incineration and energy recapture systems, making the plant legislationcompliant and energy-efficient.

Lamination

Solvent, water based, dry powders, adhesive films, thermoplastic powders and hot melts and most recently hot melt reactive moisture cured polyurethanes (PUR's) are catered for, with the latter again dominating the range of machines delivered this decade, for reasons of cost, performance and environmental responsibility.

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

Electrostatic flocking

This process has been turned from purely an art form into close to a science in the latest range of electrostatic flocking machines brought to the market by Web Processing, which arguably makes the highestperformance flocking equipment available worldwide and which is used for all the major applications in the fabric and wallpaper industries etc.

Flocked products were often of very poor quality in previous decades, 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, so 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 the unidirectional fibre tapes (UDTs) or fabrics are combined with appropriate resin systems in accurately-controlled ratios, from which the final composite structures are moulded by laying up appropriate combinations of fabric and UDTs in such geometric distributions as will give the greatest performance to the component at the lowest weight and cost.

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

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

Experienced personnel

Web's personnel are mostly highly experience engineers and chemists with decades of experience in the company's range of processes both whilst working in the company and in their previous employments often with client companies, so they and the company as a whole can bring a wealth of experience to solve some of the most complex of process requirements.

The modus operandi of the company is to determine, with the prospective client, which technology and method of processing best achieves the required endproducts by a series of discussions with the client and appropriate raw materials suppliers, 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'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 the client's operators if necessary.