THE DMF ISSUE — PU COATED GLOVES

For some years, hundred's of thousand's of people in a variety of industries in the Western world have been protecting their hands with a relatively new type of industrial safety glove, seamless knitted nylon (polyamide) liners coated with a polymer known as polyurethane.

This new glove has found great user acceptance due to its lightness, flexibility and sensitivity and has become the "industry standard" in many different types of applications, especially amongst female workers handling small components, especially in the electronics and related industries where touch, feel and dexterity are important.

The glove is produced by dip coating a mould in the shape of a hand which has been lined with a seamless knitted polyamide glove into a dispersion of polyurethane and a solvent called DIMETHYL FORMAMIDE (DMF) which is then allowed to come into contact with water which coagulates the dispersion onto the surface of the nylon (and other types of coating substrates such as Dyneema and Spectra) liner thus producing a film of polyurethane both on the inside and the outside of the nylon liner.

The mould with the liner and coagulated film of polyurethane remains in water for many hours to remove (leached out) the DMF which is known to be a toxic solvent and therefore water tanks of over 50 metres long to leach out as much DMF as possible.

These gloves are usually white in colour as they are used in "clean" areas of industry such as electronic component assembly and are used as the film of polyurethane produces no lint and does not mark sensitive components.

These polyurethane coated gloves are primarily produced in South East Asia, Korea and China being the predominant producers to the world markets.

Other manufactures in other countries have attempted to produce the gloves by the same methods but due to the highly sensitive environmental issues of using DMF and the very expensive and complicated disposal of the millions of litres of water used in the leaching process and more importantly the protection of the operatives producing gloves by this method, leading Western manufactures have employed technologies where solvents such as DMF are not used in the production process.

Information by one of China's leading producers of polyurethane coated gloves published on their web site actually states that the polyurethane production line is 80 metres in length ( some 42 metres longer than production lines found in Korea) primarily to aid the leaching process and hence the removal of DMF.

This statement and other suspicions surrounding the production of polyurethane gloves by the DMF method suggested that the removal of DMF by leaching in water could vary due to the various lengths of the machines used suggesting that gloves were leached for different times and it was therefore possible for DMF to be still present on the finished glove.

Samples of these gloves were obtained on the open market, and six pairs from various outlets were sent for analysis to a totally independent laboratory in the United Kingdom to ascertain if any DMF was present on the gloves.

These gloves are usually supplied in heat sealed plastic bags to keep them free from dust and to maintain the cleanliness and whiteness of the glove before use and the samples submitted for analysis were sent in the same type of plastic bags.

Data published by many sources have clear guidelines to how long a person should be exposed to DMF and more importantly the level of exposure, more commonly known as Occupational Exposure Limits (OEL's).

In the United Kingdom the OEL's for Long Term Exposure ( 8 hours) and Short Term Exposure ( 15 minutes) are 10 parts per million (ppm) and 20 parts per million respectively and in some countries the OEL's are less due to the highly toxic nature of DMF and environmental issues relating to the disposal of DMF.

The Test Report from the independent laboratory "Analysis for Industry" located in Essex, United Kingdom on the six gloves submitted showed that all the gloves had residues of DMF on the surfaces of the gloves, varying from 10,400 parts per million through to 49 parts per million, the lowest result being almost 5 times above the recommended OEL limit, the highest result being almost 600 times above the long term OEL limit.

It is well documented that DMF is readily absorbed through the skin, could cause cancer and could liver and kidney damage and has been shown to cause reproductive and foetal effects in animals.

The consequences of wearing gloves contaminated with very high levels of DMF over a standard working shift are fairly obvious and steps should be taken to ascertain if the polyurethane coated gloves you are supplying or issuing to your employees have residues of DMF on the surfaces of the glove. 

The major concern to all industries where these gloves are worn should be the long term effects of wearing gloves contaminated with massive levels of DMF. 

These gloves have been on the market for over ten years and the effects of wearing these gloves over many years are unknown, but we believe it is in the interest of all concerned in the Health and Occupational Safety industry to be aware that the gloves that are intended to protect the health and well being of a person's hands could be actually damaging that person's health.

SOURCE: http://www.jwcgloves.com