纺纱学第1章-40

(5) Staple fibers • Natural fibers:
Plant fibers: Cotton, Ramie, Flax Animal Fibers: Wool, Spun பைடு நூலகம்ilk • Man-made staple fibers: Polyester, Nylon, Acrylic, Rayon
• Post-Processing - winding, doubling & twisting
Status of Fiber Assembly
• Web – sheet of fibers delivered from a card (also used for multiple sheets of fibers in nonwovens);
When staple fibers are twisted together by the process of spinning, the product may be referred to as spun yarns.
(4) Yarn Manufacture -- or we call it short-staple spinning, refers to the conversion of a large quantity of individual unordered short-staple fibers of relatively short length into a linear, ordered product of very great length by using suitable machines and devices.
Fiber length influences: – Yarn strength; – Yarn count; – Yarn hairiness; – Yarn regularity (yarn evenness); – Processing
• Short fiber content (SFC)
• Opening - “open” large mass of fibers into tufts
• Cleaning – remove impurities
• Blending – mix required proportions of fibers
• Carding – dientangle fiber tufts into individual fibers; clean; and intimately blend
of maturity)
FIBER PROPERTIES
type
Length (mm)
Fineness Tenacity Extension
(dtex)
(cN/tex)
(%)
cotton 12-36
1-3
15-40
4-10
wool 40-150
3-12
12-18
35-50
ramie 60-85
4.9-8.1
Micronair Value for Cotton
Mi-value Fineness
under 3.1
very fine
3.1 – 3.9
fine
4.0 – 4.9
medium
5.0 – 5.9
slightly coarse
above 6
coarse
dtex = Mi ×0.394 (dependent on degree
BACKGROUND
• Objective of Yarn Manufacture -- is to convert natural and/or manmade fibers into a yarn suitable for knitting, weaving, or any other specified use.
• The object of yarn manufacture: Fiber
• The product of yarn manufacture: Yarn
• The process to convert fibers into a yarn: Yarn manufacture
Base Terminology
国纺织出版社。 • 苎麻纱线生产工艺与质量控制，郁崇文主编，东华
大学出版社。 • 绢纺学，中国纺织大学主编，中国纺织出版社。
• 中国纱线网： • 中国纺织机械网:
• Websites of:
Uster, Rieter, Marzoli, Savio, Schlafhorst, Suessen, Zinser, Murata, Trutzschler
Direct yarn number = weight (or mass) length
• Indirect: Based on length per unit mass
Indirect yarn number =
length
weight (or mass)
Direct Count Systems
Textile Processing Chain
Natural & MMF
yarn manufacture
nonweaving
Yarn
knitting, weaving
(dying & finishing)
Fabric
garment manufacture
Garment & other textiles
Classification of yarns
• Spun yarns (staple-spun yarns, short-staple yarns)
• Filament yarns • Compound yarns (covered and
core-spun) • Fancy yarns
(3) Spun Yarn -- A staple-spun yarn is a linear assembly of staple fibers, held together, usually by the insertion of twist, to form a continuous strand, small in cross section but of any specified length; it is used for interlacing in process such as knitting, weaving, and sewing.
Fiber fineness influences: – Yarn strength; – Yarn count; – Yarn regularity; – Yarn stiffness ; – Aesthetics
Fiber and Yarn Numbering Systems
• Direct: Based on mass per unit length
The proportion of short fibers has an extremely great influence on the yarn parameters.
SFC is specified as the percentage of fibers shorter than 16 mm for cotton, and 30 mm for wool.
FIBER PROPERTIES
• Fineness
• Density
• Length
• Luster
•
Tensile properties: Strength,
•
Moisture absorption
extension,
• Resiliency
Flexibility
• Thermal
• Cohesion
doubling • winding
Processing Stages
• Preliminary processing • Pre-carding (opening, cleaning&blending) • Carding • Combing • Drawing • Roving • Spinning • Downstream processing
• Cotton(Ne): number of 840 yard hanks which weigh 1 pound;
• Worsted(New): number of 560 yards per pound;
• Woolen(Nwr): number of 1600 yards per pound
纺纱学
Yarn Manufacture
印霞
xyin@ Phone: 67792701
Room: 4018
主要参考资料
• 纺纱学，郁崇文主编,中国纺织工业出版社。 • 纺纱原理，于修业，中国纺织工业出版社。 • 棉纺工艺原理，陆再生主编，中国纺织出版社。 • 棉纺设备，陆再生主编，中国纺织出版社。 • 毛纺学（上、中、下），西北纺织工学院主编，中
• Combing – remove short fibers; clean; and straighten fibers
• Drawing – reduce count; blend slivers; and straighten fibers
• Spinning (Roving) – draft to required count; insert required twist (or other technique for imparting strength to yarn)
Properties
• Abrasion
Resistance