Rubber products industry is an important resource based industry sector in many countries. Latex collected from the trees is processed via two quite separate routes to produce the raw materials from which its products are made.
Over the last decade, the rubber industry has witnessed a steady and strong growth. Rubber can be deformed to a high degree of strain in a reversible manner and this special property finds use in fields as diverse as transportation, material handling, health care, and sport and leisure activities.
The Raw Materials
Latex concentrate - Latex collected in the field is concentrated (generally by centrifugation, to remove part of the unwanted serum) to a dry rubber content of about 60%. It is then preserved with ammonia to combat bacterial growth. This becomes the starting material for all natural latex products, whether produced by dipping (gloves, balloons, condoms, catheters, baby soothers and dental dams) or other processes such as foaming (latex foam or sponge) or extrusion (latex thread, more commonly known as Aelastic).
Dry rubbers - Latex is coagulated with acid, creped, crumbled and washed extensively to remove surplus acid (among other things) before being dried at above 100°C. Some latex that has autocoagulated in the field while awaiting collection is also processed in this way. This dry rubber is then the raw material for the production of tyres, tubings, hoses, footwears, automotive components, engineering parts, adhesives, and some household appliances. Some rubber retreading materials are also made in this way. Many of these products are manufactured from a combination of natural rubber and various types of synthetic rubber.
Natural Rubber (NR) Products
Production of latex goods - Liquid latex concentrate is first mixed with various compounding chemicals, after which formers of desired shape are dipped into the latex-mix to enable the deposition of a thin film of latex. Dipping can be done either in the presence or absence of a destabilizing chemical (coagulant dip or straight dip respectively). Generally leaching is carried out at certain stage of the process, and the product is cured at about 100°-120°C.
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In view of the protein allergy issue, more emphasis is now placed on improved leaching of the gloves to remove as much as possible of the soluble allergenic proteins during processing. This can be achieved, for instance, by adding extra leaching facilities.
Production of dry rubber goods - the process generally involves mixing and compounding of the solid dry rubber with various chemicals. In tyres, for example, carbon black fillers are incorporated for the purpose of reinforcement. Subsequent fabrication into products often involves processes such as moulding, injection moulding, extrusion and calendering. The choice of process used depends on the type of product to be manufactured. Vulcanization of the rubber products is then carried out at high temperatures (140° to 160°C).
Applications
i) Tyre Application
Tyres
Retreading Materials
ii) Non-tyre Application
Conveyor Belting, Transmission Belting and Hose
Footwear
Rubber Roller
Medical Applications
'O' rings and Seals
Dry rubber compounding, the service provides by Goodway, is to produce useful elastic products by means of cross-linking agents, thus, producing vulcanized rubber product to meet various physical properties and to ensure that rubber compounds can be easily converted or processed into shape and form of the finished products.
The basic design of a rubber compound must take note of three requirements: (1) the end-use and the service requirement of the product; (2) trouble-free processibility of the compound during manufacture; and (3) volume cost and availability of raw materials. Various types of rubber and compounding ingredients are specified in compounds to meet service requirements, processing requirements, and volume cost.
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