Production, Properties, and Stability of NR Latices
Abstract The natural latex concentrates used for the manufacture of dipped goods, such as gloves, are products both of nature and technology. They are made using the “field” latex obtained from the tree species Hevea Brasiliensis of the Euphorbiacaea family. As the name implies, this tree originates from Brazil but is today most intensively cultivated in the far east (Malaysia, Indonesia, etc.) and in parts of Africa. Nature provides the raw material, field latex, which is then modified, preserved, concentrated, and tested by scientifically developed methods to produce the commercial concentrates. At least 500 000 metric tons, dry rubber weight, of natural latex concentrates are produced annually at present, and this quantity is expected to increase steadily in the future. Field latex can be concentrated by creaming, evaporation, and centrifugation, but the latter method predominates, and this paper will be confined to concentrates obtained by this process. This paper reviews the current situation of NR latex production, the typical properties of centrifuged concentrates, and also presents results of recent research relating to the understanding of the colloidal stability of NR latex.