Introduction Categorized under mechanical bondingtechnique. Stitch bonding is a hybrid technology, whichuses elements of various technologies from nonwoven to sewing & knitting. It can be done with or without addition of athread, when no thread is used it is often termedas “Loop formation”.
Principal Locking of layers of Cross laid webs of fibres,non woven or other flat sheet into the warp knitstructure, thus combining knit fabric propertieswith base structure with selected mechanical &functional features for its end use. Stitch bonding consist of pointed needlesarranged in a row, moving reciprocal back &fourth into the fibrous layers synchronizedinsertion of stitching yarn by each penetrationof needle. Latches pulls the yarn from one sideto the other side.
Stitch bonding M/c1. needle motion2. knockover andsupport combs3. guide bar4. device for transportof the web5. fabric draw-off fromthe needle motionand fabrics take-up6. device for feedingand guiding thewarp threads
Stitch bonding systems ortechnique Stitch bonding of webs with stitchingthread.( MALIWATT TECHNIQUE) Stitch bonding of webs without stitchingthread.(MALIVILIES TECHNIQUE) Stitch bonding of webs with loop formation(MALIPOL,VOLTEX, KUNITMULTIKNIT TECHNIQUE).
MALIWATT1 Maliwatt machine 2 warp beam creel3 knitting threads 4 lap layer5 web 6 stitch-bonded material7 pad lapper
The horizontal compound needle, which operatesin conjunction with the knock-over sinker and thesupporting rail, needles penetrates through thesubstrate which is normally a cross-laid web. The stitching yarn, whichis inserted via the guidesinto the open hooks ofthe compound needles,forms stitches thatpenetrate the web.
Maliwatt application Soft furnishings, upholstery fabrics for mattresses andblankets. Transportation cloth. Cleaning cloths, fabrics for hygiene and sanitarypurposes. Secondary carpet backing. Lining fabrics, interlining for shoes and apparel. Adhesive tapes (e.g., those used for harnessing electriccables in automobiles) Insulating materials. Geo textiles, filter fabrics.
MALIPOL Malipol stitch bonding systems have thefollowing main elements. pile yarn ground fabric stitch bonding head fabric take-down and batching The compound needles penetrate the groundfabric and the stitching or pile yarn isoverlapped in the needle hook. The pile yarn is also laid on top of the pilesinker at the same time so that a tricot racking isused to create the pile and knit the yarn into theground structure.
Kunit 3-D pile fabrics distinctive folded, pile variable thickness and density ifrequired1. Compound needle bar2. Closing wire bar3. Knockover sinker bar4. Supporting bar5. Oscillating Brush bar6. Pile sinker bar7. Base material8. Fibre web
Multiknit base materials are one or two textile fabrics withopen-pile structure, preferably Kunit nonwovens. end product, the two nonwoven surface textilesare interlaced by fibers, forming an uniform andtight surface, being connected by almost verticallyarranged fibers. Special advantages are high degree of volume(bulkiness) and elasticity of compression
The compound needles take the pile fibres of bothfabrics to make them, in the middle between thetwo fabrics, into a third layer of loops. Application 1. WADDING FOR FURNITURE2. FILTER CLOTH3. INSULATION MATERIALS4. LININGS FOR CLOTHING5. HEAT- RETARDANT MATERIALS6. SOUND- ABSORBING MATERIALS
What is warp knitting Warp knitting is defined as a stitch forming process inwhich the yarns are supplied to the knitting zoneparallel to the selvedge of the fabric, i.e. in the directionof the wales. In warp knitting, every knitting needleis supplied with at least one separate yarn. In order to connect the stitches to forma fabric, the yarns are deflected laterallybetween the needles. In this manner a knitting needle oftendraws the new yarn loop through theknitted loop formed by another end ofyarn in the previous knitting cycle
Difference b/w weft & warp knittingWeft Knitting Warp knittingYarn are fed course wise direction Yarns are fed wale wise directionYarn supply is usually in the formof a cone or cheeseYarn is in one long beam or smallwarp beamsUsually latch needles are used Latch, beard or compound needlesare usedExtensibility in widthwise &lengthwise directionIt stretch in lengthwise directionHigher shrinkage Comparatively less shrinkagepropertyAny no. needed One yarn is required for eachneedle
Warp knitting movements Swing:- front to backmovement Shog:- lateral movementof guide bars Overlap:- Movement ofguide bar to wrap yarn onneedle at back of m/c Under lap:- movement ofguide bars to wrap yarnon needle at front of m/c
Start of new course Start of overlap Guide bar swinging motion Return swing after overlap Old loop closing latch Knock over & underlapmovements
Applications Apparel :- Sportswear, track suits, leisure wear &safety reflective vests. Household :- Furnishing, laundry bags, mosquitonets. Automotive :- Car cushion head rest lining, sunshades and motorbikes helmets. Industrial :- Pvc backing, production masks, caps& gloves.