Condom fear from conference paper

Edited by the Engineeringtalk editorial team Jan 31, 2006

Conference hears that natural rubber latex condoms can suffer worse than previously thought when the temperature gets too hot.

Results from accelerated and real time stability studies on condoms made from natural rubber latex have shown that accelerated ageing at temperatures significantly in excess of 50C produces changes in burst properties that significantly differ from those seen at ambient temperature.

This news came from Bill Potter from Stapleford Scientific Services at the recent Latex 2006 conference.

It has thrown doubt about the relevance of shelf-life validation requirements within EN ISO 4074:2002.

In contrast, limited data on medical gloves indicates that the Arrhenius relationship appears to be valid.

Latex 2006, organised by Rapra Technology from 24th to 25th January 2006 in Frankfurt, was well attended with a mixture of end users, manufacturers and polymer and additives suppliers.

Despite the industry being a mature market, there continues to be new developments in polymer grades, cure systems and test equipment.

Allergic reaction to the proteins present in the rubber (type I allergy) and residual chemicals (type IV allergic contact dermatitis) is still very topical.

Two approaches were presented to reduce type I sensitisation: the use of guayule latex (Yulex); and treatment of liquid latex with special anti-protein additives, such as alkali solution of aluminium hydroxide or silicon oxide (Vystar).

The reduction in protein level is reaching the limit of detection and methods may need to be developed to quantify further improvements.

As a natural product, the latex from Parthenium argentum (guayule) still contains proteins but is of a different type to those found from the Hevea brasiliensis.

The guayule latex is being commercialised and will be distributed by Centrotrade under the Yulex tradename.

Data from the German healthcare industry has shown that the introduction of powder free gloves has significantly reduced sensitisation.

For people already sensitised, or where there is a risk of sensitisation due to the number of operations, use of non-latex gloves is standard practice.

Papers were also presented on the use of latex in non-medical applications.

Revertex showed significant benefits can be achieved with the addition of latex to bitumen.

An added benefit is that viscosity is increased at higher temperatures thereby dramatically reducing binder drainage.

Latex compounds have also been developed to absorb hydrocarbon spillages or for tank cleaning.

Rapra presented the work as part of an EC funded project.

TF Instruments presented a paper on how ultrasonic resonator technology, currently well used in the drug industry, could be applied to assess the quality of latex (stability, coagulation, latex content and so on).

Its perceived high price will limit exploitation within the rubber industry.

Further developments are required to interpret the outputs from the machine.

Additives and fillers were discussed: the application of two anti-microbial agents (biocides) was presented; TMDTOA and PPDA show a broad spectrum against yeasts, moulds and bacteria.

To overcome type IV sensitisation, RT Vanderbilt presented a paper on the use of organic peroxides to cure latex articles, which overcomes the surface tackiness that is associated with the use of peroxides in an open-air cure.

Robinson Brothers also presented two safer accelerators (against type IV and nitrosamines) which exhibited better performance in polyisoprene latex applications compared with most widely used conventional accelerators.

Both have full environmental and toxicological data packages along with FDA and BgVV approvals for use in special category products and in the health sector.

The introduction of nanofillers is being explored in latex.

Two academic papers were presented by the Rubber Research Institute of Malaysia and a comprehensive paper by the Beijing University of Chemical Technology.

The Rapra international Latex conference was well attended with an increase in numbers compared with the 2004 event.

It will be held again in 2008.