In chlorination, chlorine gas is combined with the materials of the product, to produce a surface layer more resistant to harmful effects of oils, acids and agents that cause progressive cracking and eventual breakdown of unprotected rubber. It can be compared to the benefit of electroplating metal to prevent oxidation by chemical and effects of the atmosphere. And, in the same way that plating enhances a metals surface, chlorination can beneficially improve perception of a rubber products quality by reducing its surface friction coefficient. In effect, it takes away the rubbery texture and creates a silky surface finish. Chlorine is a halogen, and another halogen gas - Fluorine - is similarly used to produce the non-stick protective surfaces (Teflon TM, etc on pans and cooking utensils.

Chlorination is of a particular benefit to natural rubber. During storage and use, unprotected natural rubber products are exposed to reaction with molecules of oxygen or oxone in the air, both of which can cause breakdown of the rubber's surface structure. This can result in the rubber becoming discoloured and brittle. And, in the longer term, breakdown during use; rubber elastic bands left for some weeks on a desk top are often found to break under comparatively little stretching because of this.

In contact with a natural rubber product, chlorine reacts with each surface molecule, to form a structure that restricts future access to oxygen or ozone to the rubber and increases its barrier to absorption of oils and greases. Acidic substances combine less easily with a chlorinated surface. For these reasons, good quality housewear gloves and many other domestic rubber products are usually chlorinated.

Synthetic rubbers have different surface structures, but equally benefit from chlorination. In many cases, their tensile strength and potential extensibility is somewhat lower than natural rubber and, for that reason, more easily physically damaged. Reducing the coefficient of surface friction by chlorination can enhance a product's abrasion resistance, and improve its appearance and handling characteristics. Residual free sulphur bloom (a powdery surface appearance, similar to natural yeast on grapes) during long term storage of rubber products can also be delayed.

If a product is to be used in contact with the skin, a valuable further benefit of chlorination is the removal (or substantial restriction) of potentially dermatitic chemicals from the rubber. All rubber products contain a residual organic accelerators which, if present above a very low level, can cause contact dermatitis in people sensitive to the substances involved. The chlorination process can reduce these to a level at which sensitisation does not occur, and at the same time, largely remove or deactivate potentially harmful proteins from natural rubber products. Also, chlorinated products can be defined as "clinically clean" at the end of the process.

Chlorination, therefore, can be very beneficial to the quality of rubber products. But, it must be carried out with great care and at the right level for the product involved. Some need more, some less, and the period of the products exposure to the gas is also critical. Special processing equipment, care and experience are important factors in successful chlorination.

Dipped Latex Products Ltd has the equipment and many years of experience in this field. If your company manufactures rubber products - whether by moulding, dipping or other methods - it is probable that our chlorination can improve these at a surprisingly low cost!!

Send a sample product to us and we will be glad to demonstrate how it can benefit from our specialised processing.

Email Us: dipped.latexproducts@virgin.net

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