PPG Sdn Bhd

Glove Manufacturing Process

The basic raw material used in the manufacture of natural rubber latex exam gloves is latex concentrate which is produced from Hevea Brasiliensis natural latex using a steel tapping knife. Tapping is done at early dawn and the latex, collected in cups, is harvested several hours later and preserved with ammonia to stop it from premature coagulation. Because of its high water and non-rubber contents, about 70%, the latex is concentrated and purified by centrifugation to a 60% strength latex concentrate and stabilised using lauric soap for long term storage. The major producers of this latex is Thailand, Indonesia and Malaysia.

Before the latex can be used for manufacturing gloves it must be mixed with a recipe of processing chemicals which include sulfur, zinc oxide, accelerators, pigments, stabilisers, dewebbing agent and antioxidant. These are mixed with the latex  and allowed to mature over a period of 24-36 hours for the mix to cure. During this period the sulfur will become mixed with the rubber particles to yield a latex compound ready for dipping.

The hand molds (or formers) suspended on a continuous moving chain are first dipped into a slurry of calcium nitrate solution and calcium carbonate. The nitrate is a latex coagulant while the carbonate is a former release agent. After the nitrate and carbonate has partially dried out, the molds are next dipped into the latex compound. At this stage the nitrate immediately coagulate a layer of latex over the mold. Because a thin layer of carbonate separates the film from the mold, it help both in removing the gloves from the molds as well as in preventing the gloves from sticking together.

The freshly molded gloves in gel form are next leached in hot water to remove residual water-soluble protein and chemicals. The leaching process has became mandatory as a result of concern with allergic reactions associated with latex proteins. This step is essential to reduce residual extractable latex protein and the effectiveness is based on the amount of clean hot water used and dwell time. Beading brushes are run over the cuff ends to create a zone called beads which assist the users in donning the gloves.

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