Prevulcanised natural rubber latex is manufactured by a special process which produces concentrates particularly suitable for dipping applications. Vulcanisation is not required, and hence there is normally no need to consider vulcanising recipes or the time and temperature of cure. Other important qualities are:
- High latex stability and long storage life
- Exceptionally transparent films
- High tensile strength
- Excellent resistance to ageing
Our policy of continuous research, process development, strict production control and technical service, ensures that our products meet or exceed the requirements of our customers. Our prevulcanised latices are second to none in quality and application performance.
Characteristics
Our ML range of prevulcanised latices have several advantages over conventional, ammonia stabilised, natural latex concentrates:
No Vulcanising Treatment Required
Our ML grades are converted to vulcanised films simply by drying giving an energy cost-saving over conventional post curing latex compounds.
Compounding Is Often Unnecessary
ML latices are ready for use in many processes. Where necessary, compounding with fillers, colouring pigments, etc., is easily achieved. Typical formulations are available; alternatively, ready-made compounds can be supplied.
Exceptional Product Stability
Zinc oxide must be used with caution when compounding an unvulcanised ammonia stabilised latex concentrate, as the formation of zinc-amminia ions has a destabilising effect which results in a gradual increase in viscosity followed by eventual coagulation. Our prevulcanised latices are carefully compounded so that excess zinc oxide is reduced to a minimum; thus, the viscosity and stability changes very little upon prolonged storage, always provided exposure to temperature extremes is avoided.
The addition of chemicals such as sulphur, accelerators, etc. to natural latex starts the process of prevulcanisation in the fluid state. This process is time-related and on storage of normally compounded natural latex, vulcanisation can proceed to a level whereby the latex compound becomes non-processible due to too high a state of cure. This does not happen with prevulcanised latex where manufacturing is very carefully controlled to provide grades of consistent cure and modulus.
Coloured Products Of Consistently Good Shade May Be Prepared
Where coloured compounds are required, ball-milled dispersions of suitable mineral or organic pigments are stirred into the latex. Pigments should be of the types recommended by the suppliers for use with natural rubber latex. Products in a wide range of colours, including bright and deep shades, may be prepared. As the latex requires no further vulcanisation, the risk of change of shade which could occur during high temperature vulcanisation of a coloured article, is eliminated.
For more information please contact us on +44 (0)1706 82 82 08.
Alternatively email us at enquires@polymers.co.uk.
