| Title: HYPOALLERGENIC NATURAL RUBBER LATEX AND A PROCESS FOR
MAKING SAME Inventor(s): W. Schloman, D. McIntyre
Disclosure 286 U.S. Patent not yet issued
Users of natural rubber (NR) products have been developing hypersensitivity, including
Type I allergenicity (a systemic or immediate allergic reaction), through contact not only
experienced through the skin, but also as a result of air-borne particles that enter the
respiratory system. Therefore, a process has been developed that yields NR essentially
free of antigens (i.e. proteins) known to cause allergenicity.
Natural rubber is a preferred source of cis-1,4-polyisoprene and a major source of NR
is the Hevea brasiliensis (Brazilian) tropical tree and an alternative commercial source
of NR exists in the guayule shrub, which is native to North America.
The present invention treats NR to reduce protein levels that are substantially lower
than those using known techniques. For example, a Hevea dipped film can yield 360 m g of
extractable protein per gram of dry rubber and a commercially available HDPNR
(highly-deproteinized NR) latex produces dipped films with about 50 m g while the present
invention yields less than 20 m g. Some of the remnant proteins of the present invention
are introduced in the course of latex preparation from non-rubber ingredients, but all
remnant proteins are essentially free of antigens known to cause allergenicity.
Latex sample proteins were analyzed for known Hevea antigen content using the Guthrie
LEAP Latex ELISA (enzyme-linked immunosorbent assay) and a second set of tests employed
using murine protein polyclonal antibodies prepared by injecting female Swiss Webster mice
with rubber particle suspensions. The results support the objectives listed below.
The objectives of the present invention are (a) to provide a NR latex that is
hypoallergenic to the extent that the latex is essentially free of known antigens that
potentially will elicit immune responses in individuals, (b) purify naturally obtained
rubber and make a latex therefrom that is hypoallergenic, (c) provide a cured dipped film
of NR latex wherein the NR latex is hypoallergenic and (d) provide a hypoallergenic
semi-synthetic latex.
The latices obtained from this invention are ideally suitable for use in the
preparation of medical, industrial and consummer products such as foam rubber, coating
compositions, emulsion paints, rubber dams, bandages, adhesives, binders, garden hoses,
elastic on underware, etc. and especially dipped goods such as gloves, condoms, tubing,
balloons, rubber bands and the like. |
