Title of Invention	AN EROSION CONTROL BLANKET
Abstract	This invention relates to a process for preparation of a biodegradable erosion control blanket, comprising the steps of Retting as herein described for separation of the Anjengo and Aratory coir fibres from husk, Twisting as herein described of the Anjengo and Aratory Yarn, Weaving fibres of Anjengo / Aratory coir yarns along the warp and Arotory yarns along the weft.

Full Text

FIELD OF INVENTION This invention relates to an erosion control blanket. In particular, this invention relates to an erosion control blanket made from coir yam. BACKGROUD OF INVENTION It is generally known that coir fibres are extracted from coconut husk by retting or mechanical extraction. The step of retting allows an extraction of coir fibres by soaking husk in pond water or backwaters. In pondwater, the step of soaking is normally, carried out for 3 to 6 months. In contrast, the step of retting in backwaters is carried out for a period of 6 to 11 months. It is generally recognized that longer the period of soaking and in the presence of febb or flow of water, better is the quality of fibre. Besides retting, fibres may also be separated from the husk by mechanical extraction, though the quality of such fibres is inferior to those obtained by the step of retting. The fibres removed or separated from the husk by the process of retting or mechanical extraction are then spun into yam which are woven into mats, mattings and other products. Erosion control blankets are known in the art, and are made of synthetic yam. Thus, the slope is firstly graded, and the blanket is laid closely in contact with the soil on the slope. In the absence of such a blanket, gullies are formed, which contribute to the erosion of soil. The presence of a blanket avoids the formation of such gullies and prevents an erosion of soil. When grass is planted, the roots spread and holds the soil together and the shoot protects the soil from direct rain water drops. A distinct disadvantage with the known blankets is that it is not biodegradable. Yet another disadvantage is that such blankets woven from synthetic yarn release toxic gases and acids during a slow degradation of the blanket. OBJECTS OF THE INVENTION An object of this invention is to propose an erosion control blanket which is biodegradable. Another object of this invention is to propose an erosion control blanket which has the required strength properties. Still another object of this invention is to propose an erosion control blanket which prevents a filtration of soil and only allows water to flow therethrough. Yet another object of this invention is to propose an erosion control blanket which substantially arrests the movement of soil. Afiirtherobject of this invention is to propose an erosion control blanket which is efficient. DESCRIPTION OF INVENTION According to this invention there is provided a biodegradable erosion cohtrol blanket comprising a woven fabric having Anjengo or Aratory coir yarns, along the warp and Aratory yams along the weft. Reference to Anjengo and Aratory yarns is intended to imply the geographical locations of Anjengo and Aratory in the state of Kerala. Anjengo is a yarn obtained in the geographical location of Anjengo and where the coir fibres are separated from husk by the step of retting in backwaters, and preferably over a period of 6 to 11 months. In a likewise manner, Aratory is a yarn available from the geographical location of Aratory and where the coir fibres are separated from husk by the step of retting in backwaters, and preferably over a period of 6 to 11 months. Simultaneously, such a period of retting may be reduced to 3 months if an inoculum as described in copending patent application nos.63/MAS/99, 64/MAS/99,65/MAS/99, 66/MAS/99 are employed. In accordance with this invention, the Anjengo yarn is hard twisted with 30-39 twist per foot and with an approximate scorage of 12 to 20. In the instance of Anjengo M yarn available in the location of Mangadan, the approximate scorage is 10 to 15. The ends perdecimeter are 9 to 19 ends/dm. The moisture content of Anjengo yarn obtained from fresh water is 15 to 19% and from saltwater is between 16 to 22%. The runnage of Anjengo A yarn is 200 and above and preferably between 200 to 360. The runnage of Anjengo Myarn is between 110 to 190. Reference is now made to the Aratory yarn. The moisture content of Aratory yarn is 14 to 16% when the fibres are retted in fresh water and 15 to 19% when obtained from salt water. The yam is soft twisted with 27 to 34 twists per foot. The approximate scorage is 11 to 18 with a runnage of 200 and above, and preferably 200 to 260. In accordance with one of the embodiments, the warp threads are arranged in group of three strands. The blanket has a mass of 0.7 to 1.4 kg/m2. WE CLAIM: 1. A biodegradable erosion control blanket comprising a woven fabric having Anjengo or Aratory coir yams along the warp and Aratory yarns along the weft. 2. A biodegradable erosion control blanket as claimed in claim 1 wherein the Anjengo Yam is hard twisted with 30 to 39 twist per foot. 3. A biodegradable erosion control blanket as claimed in claim 1 wherein the Anjengo Yam is Anjengo (Mangadan) yarn and hard twisted with 32 to 36 TPF. 4. A biodegradable erosion control blanket as claimed in claim 2 wherein the approximate scorage is 12 to 20 ± 5%. 5. A biodegradable erosion control blanket as claimed in claim 3 wherein the approximate scorage is 10 to 15 ± 5%. 6. A biodegradable erosion control blanket as claimed in claim 2 wherein the runnage is 180 and above and preferably 180 to 360 + 5%. 7. A biodegradable erosion control blanket as claimed in claim 3 wherein the runnage is 110 to 190 ± 5%. 8. A biodegradable erosion control blanket as claimed in claim 1 wherein the Aratory yarn is soft twisted with 27 to 34 TPF. 9. A biodegradable erosion control blanket as claimed in claim 1 wherein the Aratory yarn has a runnage of 200 and above, and preferably 200 to 260. 10. A biodegradable erosion control blanket as claimed in claim 1 wherein the ends/dm of the Anjeno yarn is 11 to 19 ends/dm. 11. A biodegradable erosion control blanket as claimed in claim 1 wherein the Aratory yarn has 7 to 14 picks/dm. 12. A biodegradable erosion control blanket as claimed in claim 1 having a mass of 0.7 to 1.4kg/m2. 13. A biodegradable erosion control blanket as claimed in claim 1 wherein the warp threads are arranged in group of three yarns. 14. A control erosion blanket substantially as herein described. DATED THIS 25^" DAY OF JULY, 2000.

Documents:

588-mas-2000-abstract.pdf

588-mas-2000-claims filed.pdf

588-mas-2000-claims granted.pdf

588-mas-2000-correspondnece-others.pdf

588-mas-2000-correspondnece-po.pdf

588-mas-2000-description(complete) filed.pdf

588-mas-2000-description(complete) granted.pdf

588-mas-2000-form 1.pdf

588-mas-2000-form 26.pdf

588-mas-2000-form 3.pdf

588-mas-2000-form 5.pdf

588-mas-2000-other documents.pdf