Rubber Tubing Made From Natural Latex

Natural latex is a milky white secretion that is found in a variety of plants.  Commercially latex comes from two plant sources.  The most common source is the Hevea Brasiliensis tree.  These trees are grown on large plantations typically found in places like Liberia, Malaysia, Thailand, and Indonesia.  A newer source is the guayule bush that is native to Mexico and southwest United States.

The majority of the latex produced is converted into dry stock or sheet stock.  A portion remains in latex form.  Whether in dry or latex form, ingredients must be added to improve the properties of the finished product.  These ingredients include anti-oxidants to improve aging, and a cure package to improve the physical properties.  The most common cure package contains sulfur and activators. This cure method is know as vulcanization.

The procedure by which ingredients are added is known as compounding.  To add these ingredients to dry stock, the stock first needs to be broken down.  This is known as mastication.  The stock is passed through rollers that shear the rubber breaking down the polymer chains.  The compound ingredients are then added and forced into the stock, as it passes between the two rollers.  This dry compounded stock is easily molded or extruded into a finished product.

Latex processing is much different.  Latex is compounded in its natural liquid form. Mastication is not required.  The compound ingredients are made into water dispersions which are added to the latex.  The compound ingredients are more evenly distributed in with the micron size polymer particles and the result is a product with greater tear resistance and superior physical properties.  This is one reason why medical exam gloves, condoms, and balloons are made from latex and not from dry stock.  Processing latex into a finished product is more time consuming, tedious, and hands-on, but the end result is a better product.