Natural Latex concentrate – specifications for general-purpose types.

The general-purpose grades of natural latex concentrate are subject to the requirements of international standards. They have been technically specified for many years in certain countries and the establishment of international standards indicates the substancial measure of agreement that has been achieved on the characteristics which are required of good quality natural rubber latex. The national and international standards are substantially identical in their requirements.

Natural Rubber

High Ammonia (HA) – centrifuged

Centrifuged natural latex preserved with ammonia only or by formaldehyde followed by ammonia.

This general purpose type latex is finding application in a wide variety of products including dipped goods, extruded thread, foam rubber, adhesives, carpet backing and as a binder for rubberised coir. The ammonia (alkalinity) content of HA Latex is is not less than 0.6% on latex %.

Low Ammonia (LA-TZ / TMTD/ZnO – centrifuged

Centrifuged natural latex preserved with low ammonia with other necessary preservatives.

The ammonia content of LA Latex is not exceeding 0.29% on latex . Low ammonia – LA-TZ can replace HA latex in all normal latex appications, with a little adjustment in compounding in certain cases. LA-TZ is preserved with 0.2 ammonia together with a suitable combination of zinc oxide (ZnO) and tetramethylthiuramdisulphide (TMTD) of not more than 0.1% in total, based on latex weight.

The low toxicity level and low dosage (US FDA allows up to 1.5% TMTD in products) of the secondary preservatives, which are widely used in the rubber goods manufacturing industries, ensure that this type of latex is suitable for use in all latex products including surgical goods. No additional effluent problems are expected from the use of this type of latex. The main attribute of LA-TZ latex is the greatly reduced atmospheric pollution with ammonia gas in factories. Other advantages include good film colour and the elimination of the deammoniation process, e.g. in latex foam manufacture.

As per ISO-2004(‘88E), and ASTM D1076-88

Según ISO-2004( ‘ 88E), y ASTM D1076-88.

Double Centrifuged (DC)

Double centrifuged (DC) latex is a highly purified latex concentrate prepared by re- centrifuging the first centrifuged latex which has been suitably diluted. As a result, the non-rubber constituents are further reduced. Films prepared from DC latex exhibit good clarity, low water absorption and high dielectric properties.

DC latex finds application in surgical dipped goods and other specialised premium latex products where these properties are important. The latex is generally very stable and has good storage properties.

High Dry Rubber Content (DRC) Latex

A high dry rubber content (65-67%) latex is prepared by centrifugation, providing an alternative to creamed and evaporated latices. It processes similarly to 60% DRC centrifuged latex, but dries faster. It has been used in latex thread production.

Other grades in particular with low protein level are available on request.


Latices

Special Latices