Sewing thread properties

The relevant sewing thread properties affect the appearance and performance of a seam based on their interaction with the fabric properties. Thus the important thread properties from that point of view are ... 

In conclusion, among all the sewing-thread properties discussed above, the one that is most significant from the seam pucker point of view is initial tensile modulus and tensile extension. 

Uses Lipophilic surfactant emulsifier in formulations of liq. and semi-liq. solv. waxes for floors, vehicle waxes and furniture polish preparation of cosmetic creams and lotions auxiliary for carding and spinning syn./nat. fibers increases wetting of non-woven fabrics lubricant for nylon and polyester sewing threads Properties Liq. sol. in water sapon. value 40-50 acid value 2.0 max. hydroxyl value 96-108 HLB 16.7 (calculated)... 

Sewing thread lubricants based on silicone have been tried and proven in final finishing of sewing thread to Improve the sliding properties and to Improve their resistance to heat. The sewability is improved, the number of thread breaks reduced and the lustre of the sewing improved. 

Spontaneously extensible filaments, which may be considered to be the opposite of shrink fibers are useful, e.g., in sewing thread in order to prevent seam pud ring, but may also be employed to increase the bulk of yarns by plying these filaments with standard or shrink fibers. To make fibers that have the property of ntaneous extensibility when heated in hot water, Du Pont discloses in a patent some woric-ing methods, which can be summarized as fdlows. 

The durability and security of the seam are directly related to the properties and the integrity of the sewing thread under normal use and laundering conditions. 

In order to visualize the development of pucker, a model (Figure 3.3(a) and (b)) is shown to understand the deformation of fabric stmcmre due to the insertion of a seam in it. This stitching line or a seam has to find a position on and in the plane of the fabric. In order to accommodate the bulk of stitch, the fabric yam in both directions gets displaced around this juncture. Depending on the physical and mechanical properties of the fabric, the sewing thread may have no resistance from the fabric and would manifest in different types of yam movements (distortions) in the fabric structure otherwise due to resistance from the fabric, only compression of the thread and fabric yam may take place. The former causes severe pucker and the latter causes little or no pucker. It is either the yams parallel to the seam, or the ones perpendicular to the seam, that absorb the longitudinal and lateral... 

The physical movement of the fabric yarn may offer differential resistance depending upon the fabric properties such as cover factor, tensile extensibility, bending and shear rigidity, frictional hysteresis, thickness, and lateral compressibility. However, the extent of pucker would depend upon the amount of resistance to the yam offered by the fabric properties and the tension developed in the sewing thread. 

The introduction of the sewing thread in the structure of the fabric triggers deformations, which may be dissipated into the bulk of the fabric or result in the development of pucker. The factors that would come into play are the physical and mechanical properties of the fabric, tensile properties of the sewing thread, and some sewing machine parameters. 

Yarn diameter compressibiiity If the fabric properties are such that very little movement of the yam takes place (high fabric cover) due to the insertion of the sewing thread, then the sewing thread and the adjoining yarns of the fabric are compressed. Therefore, a sewing thread that has greater compressibility will tend to cause less fabric yam deformation and subsequently less pucker. 

When force is applied perpendicular to the plane of the fabric, a catain amount of fabric compression takes place, decreasing its thickness. These fabric properties are compressional energy and actual thickness compression. The extent of compression depends upon factors like the original fabric thickness, fabric constmction (weave or sett), crimp, and fiber content. The sewing thread under tension compresses the fabric laterally in order to reduce the thread stretch and hence relaxes the tension developed during sewing. 

When a tensile load is applied to a fabric seam, it has to overcome two types of frictional forces. One is the inter-yam frictional forces within a fabric, and the other is the frictional force of the stitch assembly. The former is dependent upon the crimp, yam diameter, fiber content, and number of cross-over points. The latter, however, is dependent upon the fabric properties like fiber content, type of yam (spun or filament), thickness, lateral compression, cover factor (threads per cm), bending, shear, tensile and surface roughness, and coefficient of friction. It is also dependent upon the properties of the sewing thread like fiber content, diameter, coefficiait of Mction, initial modulus, and extensibility. All of these properties, together with the machine variables like needle and bobbin thread tension and the stitch length, make up the frictional force of the stitch assembly. Thus different combinations of these would be expected to provide different frictional resistance and hence different loads at which seam slippage may take place. 

A sewing stitch may be formed without any material, inside a material, through a material and on a material. All stitch types are formed by a needle penetrating into a fabric while transporting a sewing thread. It is essential to understand how the unique characteristics of every stitch type are dependent upon the mechanical actions of the sewing machine and fabric type, which determines the stitch properties. 

To get perfect stitch sewing, sewing thread selection must be in accordance with the properties of materials that are being sewn. This provides for the optimal strength, flexibility, durability, safety and appearance of the seam, as well as the appearance of garment. Therefore, it is necessary to use standards for stitches and seams, such as ... 

Stitch formation defects Fabric properties Quahty (size and type) of the sewing threads... 

Mandal, S., Abraham, N., 2010. An overview of sewing threads mechanical properties on seam quahty. Pak. Text. J. 59 (1), 40-43. 

Another parameter to evaluate the bending properties is the sewability of multiple conductive fibers. The method adopted for this evaluation is the curl test described previously (no International Standard available) it is able to check the residual curling of a conductive wire compared to a conventional sewing thread (Orth, 2002). As mentioned previously, adding conductive properties with a metal part, the mechanical properties are affected and the curl test allows us to understand if a conductive wire is eligible for machine sewing or not. 

Rudolf, A., and Smole, M.S., Structure-Properties Relations of the Drawn Poly (ethylene terephthalate) Filament Sewing Thread , Journal of Applied Polymer Science, 110,2641-2648, 2008. 

The importance of frictional properties largely exceeds the area of domestic fabric softeners. They are also key in the textile industry, as they condition the slipping of fibers over each other in all mechanical processes [20], Friction causes breakage of threads and generates static electricity. More generally, softened fabrics are pressed and sewed more easily, as there is less resistance to the metal movement. They also relax more quickly at the dry state since fibers slide over one another more easily. However, it is more difficult to cut fabrics with scissors as the blade slips over the fibers and fewer fibers are tom during cutting [20],... 

Many of the problems described in the previous sections result from adverse process conditions that cause systematic or random defects. Poor properties of the materials being processed — fabrics and threads wearing-out of the sewing machine s components or needles incorrect settings or bad choice of components such as feed-dogs, presser-feet or needles aU of these can be the source for the problems described. The machine operators and quality control team have to be alert to detect these situations as early as possible, because often these defects go unnoticed for whole batches. 

The preform weight per unit area can be considered as one of the most important characteristic quality values. During the sewing process, a specific amount of threads is put into the fiber reinforcement. If it is not the purpose to increase the mechanical properties of the laminate in the thickness direction, the amount of fibers put into the arrangement is the dominating factor in terms of inplane fiber movement. Thus, the thread has to be defined by taking into account these effects. 

---