Gutta Percha

views updated May 11 2018

Gutta Percha

Gutta percha is a rubberlike gum obtained from the milky sap of trees of the Sapotaceae family, which are found in Indonesia and Malaysia. Once of great economic value, gutta percha is now being replaced by plastics in many items, although it is still used in some electrical insulation and dental work. The English natural historian John Tradescant (c. 15701638), introduced gutta percha to Europe in the 1620s, and its inherent qualities gave it a slow but growing place in world trade. By the end of World War II (19391945), however, many manufacturers switched from gutta percha to plastics, which are more versatile and cheaper to produce.

Sumatra, one of the largest islands of Indonesia, is the worlds leading producer of gutta percha. The island is home to many plantations of Palaquium oblongifolia and Palaquium javense trees. The trees reach 6681 ft (2025 m) in height; the lance-shaped leaves, usually 6 in (15 cm) in length, have featherlike vein patterns called pinnate venation. The greenish flowers, about 0.4 in (1 cm) wide, contain pollen-bearing stamens and seed-bearing pistils. The seeds contain a butterlike fat that is used as food.

Gutta percha sap is extracted from the leaves. The leaves are ground up and boiled in water, and the gum is removed. At room temperature, the resulting gum forms a hard brown substance that can be molded if softened by heat; the melting point of gutta percha is 148°F (64°C). It is dielectric, which means that it can sustain an electric field but will not conduct electrical currents. This property, combined with its resistance to alkalies and many acids, made it a good insulator for undersea cables until better synthetic insulators were developed in the 1940s. Its resistance to acids also made it a good material for acid containers, but plastics have also replaced gutta percha in these products.

Up until the 1990s, the primary use of gutta percha was in the manufacture of golf ball covers, for which hard, resilient qualities are desired to withstand the golfers strikes without shattering or chipping. However, plastics have replaced gutta percha in this product as well.

Gutta Percha

views updated May 21 2018

Gutta percha

Gutta percha is a rubberlike gum obtained from the milky sap of trees of the Sapotaceae family, found in Indonesia and Malaysia. Once of great economic value, gutta percha is now being replaced by plastics in many items, although it is still used in some electrical insulation and dental work. The English natural historian John Tradescant (c. 1570-1638), introduced gutta percha to Europe in the 1620s, and its inherent qualities gave it a slow but growing place in world trade. By the end of World War II, however, many manufacturers switched from gutta percha to plastics, which are more versatile and cheaper to produce.

Sumatra, one of the largest islands of Indonesia, is the world's leading producer of gutta percha; the island is home to many plantations of Palaquium oblongifolia and Palaquium javense trees. The trees reach 66-81 ft (20-25 m) in height; the lance-shaped leaves, usually 6 in (15 cm) in length, have feather-like vein patterns called pinnate venation. The greenish flowers, about 0.4 in (1 cm) wide, contain pollen-bearing stamens and seed-bearing pistils. The seeds contain a butter-like fat that is used as food.

Gutta percha sap is extracted from the leaves—unlike rubber, which is collected by producing incisions on the tree trunk. The leaves are ground up and boiled in water , and the gum is removed. At room temperature , the resulting gum forms a hard brown substance that can be molded if softened by heat ; the melting point of gutta percha is 148°F (64°C). It is dielectric, which means that it can sustain an electric field but will not conduct electrical currents; this property, combined with its resistance to alkalies and many acids, made it a good insulator for underseas cables until better synthetic insulators were developed in the 1940s. Its resistance to acids also made it a good material for acid containers, but plastics have also replaced gutta percha in these products.

The primary use of gutta percha now is in the manufacture of golf ball covers, for which hard, resilient qualities are desired to withstand the golfer's strikes without shattering or chipping. However, plastics may soon replace gutta percha in this product as well, as the Dunlop Rubber Company has produced a plastic golf ball cover that is almost identical to the covers using gutta percha.

gutta percha

views updated Jun 27 2018

gutta percha A latex, mainly of Sapotaceae but also of Eucommiaceae and some Celastraceae. Palaquium gutta, of Sumatra, Java, Malaya, and Borneo, is the main source. The latex is obtained by tapping the bark or by crushing the leaves in hot water. It is a better thermal and electrical insulator than rubber, almost non-elastic, and plastic above 82°C. It is now used only for temporary dental stoppings, but formerly it was used for submarine telephone cables and golf balls.

gutta-percha

views updated May 18 2018

gutta-percha (gut-ă-per-chă) n. the juice of an evergreen Malaysian tree, which is hard at room temperature but becomes soft and plastic when heated in hot water. On cooling gutta-percha will retain any shape imparted to it when hot; in dentistry it is used in root fillings.