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American Institute of Marine Underwriters |
Commodity Search Form
FIBERS
- Description: HEMP - Unlike jute, does not readily powder and deteriorate. If water penetrates the bales to any extent, or if the bales are subjected to conditions of humidity, the material may become moldy and discolored and the fiber deteriorate. Hemp is a vegetable fiber obtained from the hemp plant (Cannabis sativa), which is native to central Asia. The hemp plant is a member of the hemp family (Cannabaceae). The plant grows to a height of 3 - 4 m. The male plants (fimble hemp) ripen earlier and must be harvested earlier. These plants yield particularly fine fibers. The female plants are more highly branched and bear denser foliage. The whitish to yellow fibers, which are highly water-resistant and have good tensile strength, reach a length of up to 50 mm. Similarly to cotton, the majority of hemp consists of cellulose. Hemp is also known as soft hemp and should not be confused with Manila hemp or sisal hemp, which are hard fibers. Processing methods are similar to those for flax. Cold water retting takes 20 - 30 days, hot water retting 3 - 4 days. Due to the greater hardness of the hemp fiber, mechanical processing is more difficult than for flax. The spinnable length of the hemp fiber is 70 - 80 cm. The internal structure of the hemp stalk is largely similar to that of the flax stalk. The processable fiber is somewhat larger because the hemp stalk is substantially longer. Hemp fibers have oval or rounded polygonal cross-sections with an irregular lumen, which is often narrowed to a slit. The crude fibers are combed with hatchels to yield the long spinnable fibers, the short fibers (pluckings or tow) remaining between in the steel teeth of the comb.
- Index: 831
- Commodity Name: FIBERS