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Faculty of EngineeringDepartment of Textile Engineering

PRODUCTION OF DENIM FABRICS USING SHEET DYEING AND ROPE DYEING METHODS: A COMPARATIVE STUDYSubmitted ByYousuf Ali103-23-2102Md. Nasir Uddin103-23-2207Md. Abu Owaheduzzaman093-23-1785What is denim fabric?

According to Textile Terms and Definition Denim is traditionally a 3/1 warp face twill fabric made from yarn dyed warp and un-dyed weft yarn

3/1 RHT3/1 LHTThe word denim probably came from the name of France, serge de nimes serge (a kind of material/fabric) from Nimes (a town in France) at 17th century.Leob Strauss started a wholesale business of denim at the first of 18th century in America by the name of Levi. Cowboys who often wore denim in the movies became very popular at around 1930 which lead to an increased interest in the rugged trousers.The History Of DenimFewer jeans were made during the World War 2 at 1943 for American soldiers. After the war, rival companies, like Wrangler and Lee, began to compete with Levis for a share of the international market.Denim became very popular with young people in the 1950s. Some schools in the US went so far as to ban students from wearing denim at that time.Manufacturers started to make different styles of denim to match the 1960s fashions.Denim become fashionable cloth at around 1990s. And now denim is the most usable cloth for men and women for all ages.Slasher Denim: Dyeing and sizing are done in form of sheet/ slasher simultaneously and that is why the process is also called sheet dyeing and the denim is sheet denim.

Rope Denim: Warping and dyeing are done in the form of rope and dyeing sizing is done separately. Types Of DenimFlowchart Slasher Dyeing

Photo of Slasher Dyeing

Flowchart of Rope Dyeing

Photo of Rope Dyeing

100% cotton or polyester blend yarn is used where count range is 7OE to 40OE for slasher and up to 20OE for rope.

Steel for zipper, snaps and buttons.

Leather, plastic for level.

Raw materialsIndigo vat dye: it is natural organic dye achieved from plant. But now several thousand tons of indigo produced each year is synthetic.

Dyes used in denim

Sulphur Dye: These dyes are so called because they contain sulphur atoms in their molecules.

Dyes used in denim

CriteriaRequired floor spaceMan powerCountFloor space is comparatively higher for rope denim productionComparison between Sheet & Rope Denim Comparison CriteriaRequired floor spaceMan powerCountLess man power required for slasher denim production.Comparison between Sheet & Rope Denim Comparison CriteriaRequired floor spaceMan powerCountHigher count is used for slasher denim.Comparison Comparison between Sheet & Rope Denim CriteriaLapper tendencyDye bath capacityShade variation.Lapper tendency is higher in rope dyeing than slasher dyeing.Comparison between Sheet & Rope Denim Comparison CriteriaLapper tendencyDye bath capacityShade variation.Dye bath capacity of slasher is lower than rope dyeing machine .Comparison between Sheet & Rope Denim Comparison CriteriaLapper tendencyDye bath capacityShade variation.Lower shade variation in rope dyeing process.Comparison between Sheet & Rope Denim Comparison CriteriaProduction breakage rate WastageProduction of rope denim is about 50% higher than slasher denim.Comparison between Sheet & Rope Denim Comparison CriteriaProduction Breakage rate WastageBreakage rate of Slasher is higher than rope method.Comparison between Sheet & Rope Denim Comparison CriteriaProduction breakage rate WastageWastage of Slasher is higher than rope method.Comparison between Sheet & Rope Denim Comparison CriteriaProduction of Stripe fabricLCB process warping.Stripe fabric can be produced only by rope method. Not possible for slasher.Comparison between Sheet & Rope Denim Comparison CriteriaProduction of Stripe fabricLCB process warping.No need of LCB process for slasher method. For rope, it is need to do re-beaming. Comparison between Sheet & Rope Denim Comparison CriteriaProduction of Stripe fabricLCB process warping.Direct warping is done for slasher while, ball warping for rope method.Comparison between Sheet & Rope Denim Comparison Denim typeWeight (oz/sq. yd)Sheet denim (price)Rope denim(price)Regular6-141.55 to 2.1 $1.75 to 2.25 $Multi count6-141.75 to 2.15 $1.9 to 2.35 $Slub 6-141.8 to 2.25 $1.95 to 2.45 $Stretch(regular)10-122.15 to 2.65 $2.35 to 2.85 $Stretch(multi count)10-122.40 to 2.80 $2.55 to 3.0 $Stretch(slub)10-122.40 to 2.90$2.60 to 3.10 $Sales prices of denimSales price of denim is about 1.5 $ to 3.0 $ per oz.Price of slasher denim per oz is about 1.5 $ to 2.9 $.Rope denim price is about 1.75 $ to 3.0 $ per oz.Sales price of rope denim is 7 to 9.3% higher than slasher denim.

Sales prices of denimCount: slasher-7 to 40 Ne. rope up to 20 Ne.

Breakage rate: higher at slasher.

Man power: higher at rope.

Discussion of ResultsLapper tendency: higher at rope.

Production rate: higher for rope.

Shade variation: frequently seen at slasher.

Wastage: higher at slasher.

Discussion of ResultsStripe fabric: possible at rope method for LCB.Tensile strength: higher at rope denim.

Color fastness: better for rope denim.

Discussion of Results