PLASTICS MARKETS IN SPORTS AND LEISURE

Especially in sports products, plastics are increasingly being fine-tuned, to give exactly the performance required

Since the first European explorers found native South Americans playing with bouncing balls made of the sap of a local tree, polymers have been associated with sports and leisure activities. Balls, both for sports and play, are still made of rubber - and to this first development there has been added an almost unlimited list of other products, right up to the footballs for the 1998 World Cup.

The high-tech skin developed for the 1998 World Cup footballs gave them greater acceleration, but it is also another example of the contribution that plastics and elastomers are making to our sports and leisure time. Developed by the sports company Adidas AG and the plastics group Bayer, the skin was a syntactic foam produced by mixing millions of tiny gas-filled microspheres with a specially developed polyurethane compound.

When the football was kicked, the microspheres restored its shape very quickly, producing a very high elastic recovery compared with other football constructions, so that the ball deviated very little from its initial flight path.

The balls were tested in authentic football situations, in up to 4,800 shots, including 2,000 shots against a steel plate at 50 km/h (30 mph) during the course of one hour.

Market-leader Benetton Sportsystem (owner of the famous "Rollerblade" tradename) selected a special glass-reinforced nylon for the blades of its range of in-line skates and gained advantages both in appearance of the finished product and in manufacturing productivity.

Better processability made it possible to produce mouldings with a superior surface appearance, including fibre-reinforced grades. Benetton specifies jet-black and natural for its skate blades - and a consistently high depth of colour further enhances the quality image. In addition, it was possible to shorten the moulding cycles and gain higher productivity.

Sports and leisure were again linked with plastics when, in the middle of the 19th Century, the search for a replacement for ivory billiard balls stimulated the development of cellulose nitrate (Celluloid) and, slowly and hesitantly at first, the plastics industry was born.

Since then, it has come a long way. To serve the dynamic sporting and leisure sector, plastics and rubber have taken on high-tech roles almost as advanced as those in aerospace. Sophisticated carbon fibre reinforced plastics provide lightweight and highly durable shafts for golf clubs and fishing rods, and carbon/nylon composites are injection moulded using latest gas-assisted technology to produce high performance tennis racquets. A particular value of these materials is that, by selection and positioning of the fibre reinforcement, and adjustment of the polymer matrix, they can be 'tuned' to the exact performance required, and the apparently high cost of the basic materials is well repaid by the performance of the equipment.

Strength, flexibility, colour, high mouldability - and, above all, lightness - are the characteristics which take plastics into every sector of sport and leisure, whether it be compounds in thermoplastic elastomer soling for running shoes and trainers or carbon fibre composites for rowing skiffs; polypropylene and elastomer masks and snorkels for underwater swimmers and divers or nylon runners for in-line skates; ABS protective helmets for footballers or space age composites for racing bicycles.

The list is almost endless, representing large volumes of standard and technical plastics, and an expanding world market that drives development. And that is just sporting products. To it can be added large volumes of materials and products for leisure: for hobbies such as fishing, riding, cycling, walking - or simply pottering about in the garden...

Plastics and rubbers also provide an increasing amount of the buildings and structures used for sports and leisure. The worldscale stadia being built for games and athletics often have lightweight transparent canopies made of polycarbonate, and are fitted with colourful durable polypropylene seating, and may be surfaced with polypropylene artificial turf and running tracks made of recycled elastomers.

In the children's playground, "adventure" equipment such as slides, climbing frames and modules, houses and carousels are made largely of rotationally moulded polyethylene, while the springy surface around them, protecting from grazes and scratches, is made from recycled rubber.

Manufacturing products for sports and leisure is a huge and diversified industry, ranging from large multinational corporations to small craft-based specialists (who nevertheless may also have worldwide renown).

The global toys and games sector is also a major user of plastics, especially polypropylene, polystyrene and ABS.

Computer games are a "spin-off" from the electronics sector, and much the same materials use and specifications are applied. Models of all kinds, cars, trains, and self-assembly kits, are produced largely in polystyrene, capitalising on the ease with which this material can be cemented, giving hours of enjoyment.

Construction and assembly sets such as Lego, Playmobil and others depend on the strength and "snap-fit" possibilities of plastics, while soft toys are universally produced in plasticised PVC - an area where, with increasing knowledge, there is increasing care in selection and formulation of materials.

Not unlike the sporting goods sector, the toy industry is increasingly involved with plastics offering higher-performance. A very large user of "standard" plastics (such as polystyrene, polypropylene, polyethylene and PVC), it is a growing user now of engineering plastics such as ABS, nylon and polyacetal.

The industry numbers large global companies, operating in a very competitive market, and usually doing their own plastics moulding in-house. But there is always space for the smaller specialists with a bright idea, who need skilled independent custom moulding services.

The poor quality of some imported toys does not help the image of plastics generally, but legislation (especially for safety) is slowly having a beneficial effect.

The materials and processes involved run right across the whole spectrum offered by the plastics industry. The main materials and their typical applications are set out in the panel hereunder.

The processes involved are:

Injection moulding: for large and small products complex shapes, where large quantities are required, little finishing is necessary;
Blow moulding: for hollow products, containers, bottles for all purposes;
Rotomoulding: making large, hollow colourful products (such as adventure playground elements); suitable for low-volume production;
Extrusion: sheet, film, filament/fibre, tubing, hose, pipe; glazing;
Thermoforming: covers, housings and the like, produced from sheet;
Compression moulding: fibre-reinforced helmets; boat hulls, laminated skis;
Hand lay-up: polyester/glass laminates, especially large structures (e.g. boat hulls);
Vacuum bag moulding: high performance composites: racing cycle fairings;
Filament winding: high performance composite tubes, for racing bikes, pole vaulting; Pultrusion: high performance composite rods and profiles, especially for fishing rods and vaulting poles.

As well as catering to so many facets of modern life, at home and at work, plastics will have a continuing role when we are at play !