What Is Latex Foam?
Latex, the main component in the manufacture of latex foam, is a milky white liquid formed by dispersing rubber particles in water. Latex is a naturally occurring product found within the sap of over 12,000 plant species, primarily those of the tree family, and is most commonly used in the production of natural rubber.
Synthetic Latex
Latex can also be synthetically produced, however, and it is this artificial latex that is most commonly used in the manufacture of latex foam. Synthetic latex is created by mixing two materials, styrene and butadiene, both of which are obtained from petroleum, and finally by adding oil to aid the production process and help minimize cost.
Foaming Agents
Latex foam, also known as foam rubber, is manufactured in one of two ways. The most common process is known as the Dunlop method, in which the synthetically produced latex is mixed with a foaming agent containing a combination of liquid soaps that froth the latex.
Plasticisers
In order to produce extremely soft latex foam, other additives such as oils and plasticisers are added at this stage to create a very fine bubble structure. Air is then beaten into the mixture to allow it to coagulate and the resulting product is heated so that it retains its shape. This process creates the distinctive “foamy” air-filled matrix structure of latex foam.
Talalay Latex
The second method is known as the Talalay process, developed as an alternative to petroleum-based latex foam, which has been found to emit volatile organic compounds as it ages. In this second process, natural latex is encased in a partially filled aluminium mould and the air removed to create a vacuum. The substance is then frozen to -30 degrees centigrade to stabilize the cell structure and allow optimum permeability of the final material. Next, carbon dioxide gas is added at the gelling stage to create the foam-like structure and the product is heated at 115 degrees centigrade to cure the rubber and finalise the shape of the latex foam. As well as claiming to be an entirely organic method, the Talalay process also allows for greater flexibility in the production of types of latex foam, as the final materials can range from very soft to very hard as required.