Rubber threads and chords are primarily used to manufacture various types of elastic tapes mainly for foundation garments like briefs, trunks and panties. They are also used in elastic types for shorts, skirts, sportswear, sock tops, shoe uppers, head bands and wrist bands for sportsmen and travel goods.
The raw and auxiliary materials of the project are natural rubber latex (60%), potassium oleate, soap solution (10%), sulphur dispersion (40%), zinc oxide dispersion (40%), potassium hydroxide solution (10%), vulcator ZDC dispersion (50%) , Nonax dispersion SP (50%), coloring matter and coagulate (acetic acid).
The natural rubber latex is deammonized with moist and warm air just below the surface of latex while it is agitated with paddle type agitator machine. This mixture is used in the manufacture of compounding latex. Then its maturation is done at a temperature between 30 to 40oC for 10 to 24 hours, by slow agitation (10-20 r.p.m).
After the process of maturation has been completed, the mixture is cooled to below 20oC and strained through a nylon gauge or fine silk. The air bubbles are removed from the mixture by applying vacuum to storage tank for 10-14 hrs. The phenomenon is an important step in the process, because only air free mixture can successfully be used for the manufacture of threads. After removal of air from the mix, it pass through filter into a small feed tank, charged into a manifold reading to a capillaries for extrusion into the acid bath.
In the extrusion, the maintenance of constant pressure is necessary. Variation in pressure inevitably results in a thread of a non-uniform dimension. In this process, the rate of extrusion must be fast. Great care must be exercised to control not only pressure, mixture, viscosity, concentration of coagulant, immersion on depth, the angle capillaries and tension under which the threads are transformed for washing and cleaning. If these factors are not controlled, then the quality of the threads may be changed. Finally, the threads are sent for acid bath and then vulcanized by using hot air after washing with warm water. The project does not have any negative impact on the environment.
