ODORANTS

For many years a small number of firms in the United Kingdom have supplied odorants, reodorants, and deodorants (the three names having been used fairly indiscriminately) to the rubber industry. These products have two basic purposes - firstly, to mask or destroy in certain articles the somewhat unpleasant and unwanted smell imparted by the rubber or by ingredients used in the manufacture of the goods, and secondly, to impart to a material or product a definite desired odour. An example of the second group is the imparting to shoe-soling material, and to artificial leather upholstery, of a true "leathery" smell. It may be desirable to incorporate odorants of a perfume nature in products, particularly household goods, purely as a selling aid, and the use of medicated odorants in hospital equipment is an obvious advantage. In the latter instance, a strong case for the use of deodorants may be made out. These products should completely take away the odour of the rubber vulcanisate, without imparting to it any new smell.

Although odorants for the rubber industry were certainly on the market before 1930, very little research appears to have been carried out on their use, except perhaps privately by the companies marketing them. Odorants should have no effect either on the vulcanising and processing properties of the rubber, or on the other compounding ingredients to be included in the mix, and they should not themselves be affected by the vulcanising process to which the mix is subjected. Early workers apparently found great difficulty in overcoming the last of these restrictions.

Most of the literature on the subject is in the form of trade pamphlets and other advertising media, but research work during the 1930's is reported in five papers (l,2,3,4,5). It is interesting to note that in a survey held in the United States of America in 1930, "rubber" was voted by housewives and others as the third most unpleasant of a series of 56 well-known odours (6). This survey started some of the research referred to above, and apparently increased the sales of odorants considerably.

In 1932 one writer on the subject mentioned that the odour imparted to a rubber product should ally itself with the colour of the article - a point not apparently thought of to any extent since, but one well worth bearing in mind (7).

Most of the odorants and deodorants listed below are complex organic mixtures, and cannot, therefore, be described from the point of view of chemical composition. The amounts used are very small, usually being of the order of 0.25% or less on the rubber content of the mix.

References

1 Foley, M. A., India Rubb. World, 1933,88, No.3, 30, 39.
2 Jacobs, F., Rev. gen. Caoutch., 1933, 10, No. 95, 3-7.
3 Stevens, H. P. and Parry, E. J., Bull. Rubb. Gr. Ass., 1933, 15, 261-3; India Rubb. J., 1934, 88, 513-8, 541-4, 546, 569.
4 Jacobs, F., Rev. gen. Caoutch., 1935,12, No. 109, 27-9.
5 Engel, R. A., India Rubb. World, 1936, 94, No.5, 37-8.
6 Laird, D. A., Rubb. Age, N. Y., 1930, 27, 366.
7 Ising, C. E., Vanderbilt Rubber Handbook, New York: 1932, p. 87.

From Brian J. Wilson (ed), British Compounding Ingredients for Rubber, Cambridge, 1958, W. Heffer and Sons Ltd., p. 219.