Fabric knitted

A knitted fabric is produced by interlooping flexible yarns of one yarn set. The yarn is formed into loops and the newly formed loops are inter-meshed with previous knitted 

Knitting is an expensive process, but is assuming an important role in the production of 3-D fabrics. The products can be carefully designed to provide the requisite weight and degree of openness. However, the degree of openness does make it impossible to achieve high fiber volume fractions. 

The overall approach to this study is based on experimental investigations and advanced micronumerical simulations forming the ground for the subsequent predictive macronumerical forming simulations. 

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Knitted fabrics are produced from one set of yams by looping and interlocking processes to form a planar stmcture. The pores in knitted fabrics are usually not uniform in size and shape, and again depend largely on yam dimensions and on the numerous variables of the knitting process. Knitted fabrics are normally quite deformable, and again physical properties are strongly dependent on the test direction. 

Typical textile fibers have linear densities in the range of 0.33—1.66 tex (3 to 15 den). Fibers in the 0.33—0.66 tex (3—6 den) range are generally used in nonwoven materials as well as in woven and knitted fabrics for use in apparel. Coarser fibers are generally used in carpets, upholstery, and certain industrial textiles. A recent development in fiber technology is the category of microfibers, with linear densities <0.11 tex (1 den) and as low as 0.01 tex. These fibers, when properly spun into yams and subsequendy woven into fabrics, can produce textile fabrics that have excellent drape and softness properties as well as improved color clarity (16). 

Even when crimp is fiiUy developed it is easy to pull out (low energy) and difficult to translate into noticeably bulkier woven and knitted fabrics. It does however improve the absorbency and the cohesion of the staple (important in spun-yam and nonwoven making) and gives a subtiy different texture... 

The constmction of vinyl-coated fabrics varies according to its appHcation. A vinyl-coated fabric used for automobile seat covers is shown in Figure 3 a woven fabric is the substrate. The material is durable but stiff and heavy. Incorporating an expanded foam stmcture into the coating layer reduces the weight (Fig. 4), and replacing the woven substrate fabric with a soft knit fabric improves fiexibihty. 

In the calendering method, a PVC compound which contains plasticizers (qv) (60—120 phr), pigments (qv) (0—10 phr), fillers (qv) (20—60 phr), stabilizers (10—30 phr), and other additives, is kneaded with calender roUs at 150—200°C, followed by extmsion between clearance-adjusted roUs for bonding onto the substrate. This method is employed for products with thick PVC layers, ie, of 0.05—0.75 mm thickness. The main plasticizer used is di-2-ethylhexyl phthalate (DOP). For filler to reduce cost, calcium carbonate is mainly used. A woven or knit fabric made of cotton, rayon, nylon, polyester, and their blend fiber is used as substrate. For foamed vinyl-coated fabrics, the bonded materials are heated in an oven to decompose the foam-blowing... 

In the wet system, manufacture proceeds as foUows (/) a 7—20% polyurethane solution of DMF is appHed onto a fabric and immersed in water containing 0—10% of DMF for coagulation (2) the coated fabric is washed and dried (4) the surface is finished by the dry system. For the substrate, a woven or knit fabric which has been bmshed on its surface is often used to improve appearance, resistance to grain break, and feel. 

Traditional textile fabrics are made by weaving or knitting. Nonwoven fabrics are similar to woven and knitted fabrics in that both are planar, inherently flexible, porous stmctures composed of polymer-based materials. The main difference between the two is the manner in which the fabric is made. 

The stmcture of traditional woven and knit fabrics permits the fibers to readily move within the fabric when in-plane shear forces are appHed,... 

The knitted fabric is subjected to a finishing operation in which a suitable backing material is appHed to penetrate the yam contact points and stabilize the stmcture. This process is usually accompanied by a heat treatment which stabilizes the fabric and conditions the pile. 

Knitted fabric constmction characterization is discussed in ASTM D3887. Characterization of knitted fabrics includes yield (area per weight), width, length, and yam count (number of courses and wales per unit length). The type of knit is also specified, eg, warp knit or weft knit. Yarn analysis may be difficult on account of problems in raveling individual yams from the knitted stmcture, particularly warp knits. 

For knitted fabrics exhibiting high extensibiUty to failure, the ball burst test is recommended (ASTM D3787). A poHshed steel ball is pressed onto a rigidly held circle of knitted fabric. The force on the ball required to mpture the fabric is reported as breaking strength. 

Inflated Diaphragm Method (ASTM D3886). This method is appHcable both to woven and knitted fabrics. The specimen is abraded by mbbing either unidirectionally or multidirectionally against an abradant having specified surface characteristics. The specimen is supported by an inflated mbber diaphragm under a constant pressure. Evaluation of abrasion resistance can be either by determination of the number of cycles required to wear through the center of the fabric completely or by visual examination of the specimens after a specified number of cycles. 

A second wtinMe-recovery test, AATCC test method no. 128, describes the determination of the appearance of textile fabrics after intentional wrinkling followed by evaluation of appearance in comparison to standard repHcas. A visual rating from 1 (wrinkled) to 5 (smooth) is assigned. This method may be used for both woven and knitted fabrics, whereas the recovery angle method is appHcable only to woven fabrics. 

With knitted fabrics it is necessary to remove the knitting oils by either alkaH treatment or solvents. Where water-immiscible oils have been used and the fabric is to be hot dyed (80°C or above), a minimum scour to remove dirt and stains can be sufficient, the rest of the oil being removed during the dyeing process. 

In the United States tubular knitted fabric is dyed by the pad-batch method for oudets where the edge mark formed as the double thickness tube passes through the padder is accepted. In Europe it is usual to sHt tubular knitted fabric before padding in order to avoid any edge marks. 

Knit fabric A fabric structure made by interlooping yams. 

Manufactured aramid fibres are usually treated by a binder such as oils and surfactants to protect the fibre surface and improve the ability to handle. In order to remove the binder the knitted fabric is immersed in... 

These fabrics can be applied in the hand-built construction of hoses in a spiral form at an angle to the axis of the hose. The knitted fabric can also be produced directly onto the surface of the inner liner of a hose and subsequently be covered with the outer cover compound by a cross-head extruder. 

Knitgoods, dyeing, 0 171, 200, 201 Knitted fabrics, 24 619-620 Knitting, 11 178 cotton, 8 17-18 Knock, engine, 12 390-392 Knock-in mice, 12 462 Knock-out mice, 12 462 conditional, 12 467 Knock sensors, 12 394... 

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