Globalization of the economy is forcing the industry to go in for better quality cotton to make the product competitive in quality as well as price. Without quality assurance, our cotton can not fetch reasonable price and not only the exporter, but even grower will not receive a market price for low quality. Adequate availability of quality cotton is the prime concern of the industry. Gradually the share of cotton is declining in the fibre consumption by the industry, however, cotton continues to be the lifeline of the textile industry. Thus fibre quality is very important. Evaluation of fibre quality is carried out at Central Institute for Research on Cotton Technology (CIRCOT), Mumbai. The regional branches of these institute work under agricultural universities. In the laboratory physical qualities of fibre are evaluated. Following are the fibre qualities After ginning the mean fibre length is determine. It is determine by bare sorter, bolls sorter, comb sorter, A. stapling app., and digital fibograph. Using bare sorter and boll sorter mean length is determined. This length is major in millimeter (mm) or in inch. Mean fibre length is classified as follows:
With the help of digital fibograph 2.5% span length and 50% span length is determined. Span length is considered as standard in international market. Unit of span length is mm or inch. 2.5% span length is classified as follows: -
Fibre fineness is a weight of one-inch fibre. If weight is more then fibre fineness is less and if weight of one-inch fibre is less then fineness is more. To determine the fibre fineness micronaire: fineness tester, air perimeter, aerialometer is used. In international market unit of fibre fineness is militex. Militex is 37.39 times more than micronaire. Fibre fineness is classified based on micronaire as follows and unit of fibre fineness is (microgram/inch):
Tenacity is the strength of fibre. It is determine by stelometer, strength tester. For this fibre tuft is taken between strength tester or forceps and strength required for breaking load of fibre is the tenacity and it is measure in kg and then wet of fibre is taken in milligram. When fibre strength is determine without keeping distant in fibre strength tester or forceps. It is known as 0" gauge and if there is 3.2mm distant then it is 1/8 gauge fibre strength. On stelometer elongation of fibre can be determine. The unit of tenacity determination is gram per Tex. Classification of fibre tenacity as follows:
Fibre maturity depends on quantity of cellulose. Maturity of fibre is determined with the help of compound microscope. On a slide 100-200 fibre are taken and wet by solution of 18% caustic soda. After evaluation it is classified in matured, 1/2 mature and immature fibre. Using this classification maturity coefficient is determined. Classification of maturity-coefficient as follows:
Uniformity
ratio of cotton fibre is determined by digital fibograph. With the help of span length, it
is determined by following formula: Uniformity ratio = 50%
span length Uniformity ratio is determined in percentage. If it less than 47% there is increasing short fibres. Classification of uniformity ratio as follows:
In market before buying or selling, cotton graded according to classification. In cotton quality there is variation due to season and variety. Hence for cotton quality classification uniformity is essential. Besides cotton fibre quality, fibre luster and colour also considered. Fibre luster is determining by reflection of light from fibre and colour by using colorimeter. Cotton grade is determined, based on:
Generally cotton fibre is white. For classification of colour cotton, yellow colour present in cotton is counted. In India according to colour cotton is classified as follows:
In India, East India Cotton Association (EICA) fixes 6 grades. In Maharashtra cotton growers & marketing association also fixes 5 grades as follows respectively
b. 5 grades fixed by Maharashtra cotton growers & marketing association
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