Hosiery technology

1. Hosiery technology Radko Kovar, Martina Syrovatkova KTT, Technical University of Liberec, Halkova 6, 461 17 Liberec, cz

2. Brief content: 1. Principles of hosiery technology 2. Production of stockings and tights (pantyhose) 3. Production of socks and knee socks 4. Single-cylinder machines 5. Double cylinder machines 6. Machines programming 7. Finalization of products 8. Structure and properties of products 9. Supplementary information

3. 1. Principles of hosiery technology: Content: 1.1. Classification of hosiery products 1.2. Standardization of hosiery products 1.3. Materials used in hosiery products 1.4. Welts 1.5. Shaping of heels and toes 1.6. Shaping of legs 1.7. Used knitted structures and designs 1.8. Closing of toes

4. 1.1. Classification of hosiery products • The term “Hosiery products” is used for clothes, covering manly lower extremities (legs and foots) • From the point of view of fabric “fines” there are: • Fine products, usually made of multifilament yarns on knitting machines with 24 – 40 needles per 25.4 mm (fine women stocking and tights) • Course products, usually made of spun yarns on knitting machines with 5 – 24 needles per 25.4 mm (socks, knee socks, course pantyhose)

5. Machines used: • Majority of hosiery products is produced on small-diameter circular knitting machines

6. Machines used: • Another used technologies are mainly • Warp knitting • Weft knitting on flat machines. Example:

7. From the point of view of product “length” there are: • Footlets (covers only toe, foot ant heel) • Socks of different lengths • Half hoses (reach under or above the knee) • Stockings • Tights (usually sewn from 2 longer stockings).

8. 1.2. Standardization of hosiery products • In Czech Republic next standards are relevant: • CSN 804159: Elastic medical tights and compressive products • CSN 805801:Standard stockings, half-hoses, …, classification • CSN 805802 EN 13770:Measuring of resistance of hosiery products in abrasion • CSN 805810:Fine stockings, half-hoses, socks and footlets • CSN 805841:Course tights, regulation and classification • CSN 800863:Measuring of weight of knitted products • CSN 800864:Measuring of dimensions and appearance of hosiery products

9. 1.2. Standardization of hosiery products • Some chosen ISO standards: • ISO 5971:1981 Size designation of clothes – pantyhose • ISO 5971 (CSN 805044):Marking of sizes of hosiery tights • ISO 7070 (CSN 805045):Marking of sizes of hosiery products • ISO 8117:2003:Textile machinery - Knitting machines - Nominal diameters of circular machines

10. 1.3. Materials used in hosiery products • All usual textile yarns could be used, produced both from staple and continuous fibers (spun yarns, monofilament, multifilament) • Usually fine hosiery products prefers continuous fibers and course products staple spun yarns • Yarn linear density needs to correspond with the machine gauge g, usually defined as number of knitting needles per 25.4 mm (one English inch) • Roughly yarn diameter could be somewhere around l/5 of needle pitch (25.4/g) or lower

11. 1.4. Welts • Quality welt should meet next demands: • To be fast (upper border ready for use) • No or low curling • Suitable stretchability • Double cylinder machines are able to produce very suitable rib (double-faced) structure • Single cylinder machines are able to knit single-faced structureonly, tubular welt is often used

12. Mostly used types of welts: a) Rib welt (1x1 rib structure) with fast border, great stretchability, often with elastic inlayed yarn. b) Tubular welt formed by transfer of kinks of the yarn in some of initial course again on knitting needles after knitting double welt height

13. 1.5. Shaping of heels and toes • Heels and toes could be knitted as: • Reciprocated, knitted on reverse movement of the needle bed and creating “3-D” pouch on about one half of the product. • Rotation producing only tubular fabric.

14. Examples of heels • Reciprocated a) 3-D pouch on about one half of the product. b) Part above the pouch could be reinforced. • Rotation c) Producing only tubular fabric with inserted additional courses on about one half of the perimeter d) Only reinforced and shaped by thermal setting later.

15. Examples of toes • Reciprocated a) Knitted in the same way as reciprocated heel but sawn together later. b) Similar toe with inserted a group of rotation courses. • Rotation c) Only reinforced tubular part is finalized by sewing. The seem may be led from left to right side or from above down.

16. 1.6. Shaping of legs • The number of needle in circular needle bed is done. This fact limits changes of product diameter. Basic and generally used possibility is change of stitches length. • The change of the yarn consumption is connected with the change of wales and courses density and so as well with fabric diameter.

17. 1.7. Used knitted structures and designs • Mostly used single-faced structures (from single bed machines): • Plane structures • Plated structures • Plush structures • Laid-in structures All in different modifications

18. 1.7. Used knitted structures and designs • Mostly used double-faced structures (from double bed machines): • Plane double-faced structures • Rib structures • Purl structures etc. in different modifications and designs • Heels, foots and toes are knitted in plane single-faced structure. The reason is relatively flat surface and low thickness and so better comfort of user.

19. 1.8. Closing of toes • Product of circular machine is ended by tubular open part and before usage the toe need to be closed. Next two possibilities are important: • Closing the toes by sewing on product finalization • Closing the toes when knitting on circular machine. There are several used principles (see chapters 2, 3, 7)