Sustainably Sourced Kushon® Cellular Rubber


By Greg Waters, Director of Global Sales & Marketing at Griswold LLC

Griswold LLC manufacturers the majority of its Kushon® cellular rubber products using natural rubber as the polymer base. While so many of today’s foam materials are petroleum based, our natural rubber is sustainably harvested on plantations in Indonesia.  Unlike soy and corn based products, natural rubber does not divert food materials from either people or livestock.

Rubber was harvested initially in South America where it originated. The trees and seeds were highly protected.  However, British businessmen smuggled seeds out of the Amazon in the 1870s.  Those seeds were used to grow trees that generated hybrids well suited to growing in the British colonies of Southeast Asia.  By 1910, the bulk of global rubber production had shifted to Malaysia, Sri Lanka, and Singapore.

Natural rubber is produced from the sap of approximately 200 different plants.  The most productive source is the Para rubber tree, Hevea Brasilensis, which is indigenous to the Amazon.

Natural rubber is treated with sulfur and heat through a process known as vulcanization, which creates rubber with greater elasticity, strength and hardness. Charles Goodyear, in the 1830s, discovered a method that greatly improved the basic properties of natural rubber. Today, that process, vulcanization, gives our Kushon Sponge its amazing durability and makes natural rubber suitable for a wide variety of applications in areas such as automotive, industrial, footwear and die ejection markets.

Griswold’s tree-derived rubber is also eco-friendly. The trees are tapped in much the same manner that sap is collected for the production of maple syrup.  A rubber tree is capable of producing sap for about 12 years, after which the tree is replaced with a new sapling. The thin white liquid that flows from the tree is collected and shipped to a central facility where the rubber is strained to remove foreign materials, like leaves and sticks. The liquid is acidified, causing the sap to coagulate.  Once the coagulate is rolled into sheets and dried, it is sent to manufacturers to develop product components.

During production, we recycle waste for all of our natural rubber Kushon products.  At the facility, the excess material is ground into particles with a dust like consistency.  That ground product is then added to new batches of Kushon, becoming salable product and avoids being discarded in the landfill or the incinerator.

With a sustainable formulation and production process, we are able to provide our customers with tough and durable products in flexible formats for a broad range of constructions while still remaining environmentally conscious.