Our civilization had significantly been alleviated with the invention of wheels. Tires that cover up the wheels made the whole journey even smoother. Tires along with 40000 products have been simplified with the discovery of natural latex. This variety of uses of natural latex in our daily household and medical settings have made our life more convenient. But natural latex is not readily usable. It needs processing before applying for practical purposes. Latex processing involves a series of physical-chemical treatments, and it requires intensive observation from Natural latex to finished product. This article will cover the fundamental fact about latex processing.
Natural Latex: Latex is a milky colloidal polymer substance obtained from the latex tree sap. The latex sap contains 55 percent of water and about 45% of rubber content. The scientific name of the latex tree is ‘hevea brasiliensis’ Though the latex tree was first identified in Haiti, several varieties of latex trees are now available throughout the world. Among them, Amazonian grade, Congo grade are prevalent and commercially profitable trees for latex sap.
When to collect latex Sap: Not all the latex tree is capable of producing quality latex. A latex plant requires a certain amount of time to mature. It usually takes 5 to 6 years to make quality latex sap.
Tapping: latex tree tapping is a process of collecting latex sap from the tree. This tapping process includes precisely cutting a depth of 6.4 mm into the tree’s bark with a knife. This tapping process is usually done in the morning, as the rising temperature is a risk factor for latex coagulation. Tappers generally place a pot under the tree to collect the sap. This milky sap is then accumulated into a big jar. A predetermined value of preservatives(TZ and DAP) is mixed with the latex in this section..this chemical treatment is done due to maintaining optimum latex quality, whereas constant liquid ammonia supply is ensured. Mixing of ammonia prevents the row latex from coagulation.
How raw natural latex is processed into rubber: After the tapping is done, the raw NR latex is poured into a reception tank. A calculated amount of certain chemical preservatives{TZ, DAP, and Lauric acid) is added. These additives enhance the stability of natural latex. After overnight conservation of the raw latex, a significant portion of water and other impurities are illuminated employing centrifugation. After centrifuge, the NR latex is then separated into two-layer. The Heavier latex layer, known as latex concentrate, contains more dry rubber content, and the thinner layer named Skim Latex has a lower dry rubber value. Both the concentrate and skim latex is then transferred into two separate zones where two different chemical treatments are applied for further uses.
The latex concentrate, which has higher rubber values, is then stored in a cylindrical storage tank, where optimum ammonia concentration is confirmed. This liquid ammonia ensured the high-grade latex concentrate from being solidified. In this portion, a calculated amount of Additives like Lauric acid is added; these additives ensure the required level of mechanical stability, viscosity, and fluid ability of the latex concentrate. The latex concentrate is then preserved for twenty-one days in the storage tank.
The thinner layer – skim latex is then chemically treated with strong acid. Like sulphuric acid. The acid mixing process is done due to removing the basicity of the Raw latex, and hence the low concentrate rubber cluster is formed. this cluster is then
rolled into sheets in a rolling machine and then dried.
Why Vulcanizing of NR latex: The NR latex is very soft and moldable and. Upon adequate heating, it can degrade the quality of NR Latex. a certain amount of sulfur is mixed with a controlled heating system. Thus the polymer chain in NR latex is cross-linked. This process is called vulcanization. The vulcanization of NR latex improves the strength, elasticity, and durability of NR latex to a better extent.
