Search

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Determination of the instability of air-jet textured yarns is a very important aspect of their quality characterization. To overcome this problem many researchers have suggested different techniques, however none has been accepted as a standard method. Among all the methods, that suggested by Demir et al. takes attention, since it was improved after investigating the advantages and disadvantages of most of the techniques in use. Recovery from strain measurements are commonly used to get information about fiber molecular structure. In this study, instability of air-jet textured yarns was investigated by using both Demir's instability test method and recovery from strain measurements. It was observed that Demir's method is a practical and reliable way to compare the instability of air-jet textured yarns produced from the same raw material. For comparing different materials it was more beneficial to use recovery from strain measurements. [ABSTRACT FROM AUTHOR]

Stretch fabrics are used in manufacturing pressure garments to exert pressure over specific body parts in medical conditions like venous and lymphatic disorders, scar management, and bone and muscle injuries. The amount of therapeutic pressure required in each medical condition is different; therefore, there is a need to engineer the stretch properties of garments to match the requirements in each case. Limited information is available on the relationship between fabric properties and the pressure generated on the body. In this paper, an attempt has been made to study the effect of inlay yarn pre-tension at the time of manufacturing of stretch fabrics on the pressure generated by the garments. Results show that change in inlay pre-tension significantly changes the structural characteristics of the fabric but the load elongation behavior remains unchanged up to 100% extension. Pressure exerted on rigid cylindrical tubes increases with reduction factor of the fabric tube and the curvature of the cylinder. [ABSTRACT FROM PUBLISHER]

Polylactide multifilament yarns were textured in order to be endowed with properties of natural staple fibre yarns for textile applications. Texturing promotes the formation of stable secondary links between the macromolecular chains. A polylactide 167/68 dtex multifilament yarn was textured under different conditions. Relaxation experiments at yield, strain softening, strain hardening and just before breaking were performed. The relaxation behaviour was studied by the application of the generalized Maxwell model. The initial stress induced when stretched, the final non-relaxed stress after relaxation and the stress relaxed at different times were determined. Variations in the relaxation behaviour were related to texturing conditions and stretching. [ABSTRACT FROM PUBLISHER]

Elastane fibres show rubber like behavior and are highly stretchable. Basically these fibres contain polyurethane bonds. Elastic fabrics are an important route to achieve comfort by freedom of movement for body fitted with sports and outdoor wear. Elastic garments used in athletics and sports may improve the athlete's performance in cycling, swimming and so on. A great deal of research is reported on elastane structure, yam formation and fabric production. Testing of elastane and its fabric has given new dimensions in terms of results. New attempts are being made to produce the yam with blends and subsequent conversion into woven and knits, in order to improve garment elastic bahaviour and productivity. This paper reports the elastane fibre characteristics, elastane yam production method, new attempts in yam production, commercial ways of fabric manufacturing techniques, fabric properties, new testing methods to test the elastic products and its application. [ABSTRACT FROM AUTHOR]

Strength formation in twistless yarn takes place in two stages: in the first stage, partial reinforcement of matrix elements, and in the second stage, cross-linking of the matrix elements by the filler takes place. Curves that determine the strength formation of twistless yarn made of chemical fibres and blends were obtained. [ABSTRACT FROM AUTHOR]

The technology for manufacturing combined highly stretchable yarn by pneumomechanical spinning is examined. Regression models were obtained for Dorlastan V850 elastomeric fibre with 4.4 tex linear density. Examples of the dependence of the breaking load of the highly stretchable yarn on the twist and stretching value of the elastomeric component are reported. [ABSTRACT FROM AUTHOR]

This paper presents an investigation into the behaviour of fabric with elastane yarn during stretching. The aim of the research was to study the viscoelastic part of the stress-extension curve and behaviour of fabrics with elastane yarn after one hour stretching above the yield point. Research results of the viscoelastic part of the stress-extension curve show low values of stress and extension in the yield point (extension at the yield point is from 0.25% to 0.75%), which means a larger area of the viscoelastic behaviour of the fabrics was analysed. The results of research into the viscoelastic properties of fabrics with elastane yarn also show greater differences in viscoelastic properties on the stress-extension curve above the yield point, which means that the elastane in the yarn had started to affect the viscoelastic properties, with an extension which is higher than the one at the yield point. The results of the research also show that elastic extension after one hour of stretching the fabric to the specified extension of 25% is higher than the extension at the yield point, which moves between 22.2% and 24.1%. This figure is considered to be very high. [ABSTRACT FROM AUTHOR]

The problem when finishing elastic articles is that maximum stretchability and elastic properties must be achieved while maintaining other technological features (final width, weight per square meter, dimensional stability, etc.). In this paper, three com- mon process concepts with different process routes are described and compared. The practical results that can be obtained clearly show the advantages and disadvantages of each of the concepts as well as the article-specific limits of these concepts. An important finding here, however, is that it is not possible to make a general statement on the most suitable process route. Elastic articles are very sensitive to marks and should, in the majority of cases, be processed open/width. Low tension treatment of the fabric is also particularly important. For this purpose Benninger has developed a homogeneous machine concept based on the Trioflex drum washing machine. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to an article on the mechanics of torque-stretch yarns, by J. W. S. Hearle in 1966 and 1972 issues.

The article discusses the comparative spinnability of ring- and rotor-spun cotton yarns. Ring-spun yarns produce better correlation coefficients compared to rotor-spun yarns. Regarding the contributions made to this coefficient, for ring-spun yarns, fiber tenacity is the most significant parameter for yarn evenness and tenacity, whereas the fiber length and uniformity ratio impact the breaking elongation. For rotor-spun yarns, the results are more dependent on the yarn linear density. Fiber-breaking elongation influences the yarn parameters more in rotor-spun yarns than the ring-spun variety.

The section of "The Production of Textured Yarns by Methods Other Than the False-Twist Technique," focuses on various texturing methods for the production of yarn. A table depicting the relative strengths of the various texturing processes in 1974 is presented. The false-.twist method of texturing is generally used for the production of yarns for outerwear from continuous-filament yarns, especially where stretch is required and where the double-jersey knitting machine is employed. Another method generally used is that of air-jet Texturing.

The section of "The Production of Textured Yarns by Methods Other Than the False-Twist Technique" focuses on the extrusion method of producing yarn. Extrusion method reduces the number of processing stages. It is reported that side-by-side extrusion of two components with a different shrinkage potential does not in itself provide a sufficiently bulky yarn. A further stage is need to develop the bulk or a more complicated and thereby expensive extrusion technique must be used. The multicomponent-extrusion technique was used originally for the production of stretch yarns from nylon-based components.

The article discusses the paper about the structure ratio, E, and its application in fabrics, which was presented in the Diamond Jubilee Conference of the Textile Institute. Structure ratio, E, is a ratio of stitch length and the geometrical mean length of the two sides of the unit pattern cell enclosing the stitch. The geometrical nature of E is significant in the knitted structures of locknit fabrics. Likewise, two theoretical models were presented representing the two states of fabric, relaxation and stretch.

Equations are given that relate the structure of spirally wrapped elastomericfibre core yams to their stretch properties. The model employed improves upon previous ones by considering the effect of covering-yarn diameter. Graphs are given that facilitate the use of the theory for manufacturing purposes. A comparison with available experimental data indicates an improved agreement between actual and predicted values of retraction in the most important case, where the input and output yam lengths are measured. It is expected that the improved theory given here will show to much greater advantage with the present commercial fine-core wrapped structures. In the special case where the wrapping or covering yarns have very low twist, the basic theory is inadequate. Modifications to account for compression of the cover yam are accordingly included to enable an approximate relationship between yam structure and stretch to be obtained in this case. [ABSTRACT FROM AUTHOR]

A processing programme is outlined in which yarn pre-twist, applied air-pressure, and supply-yarn overfeed are systematically varied in the air-jet bulking process to investigate their effects on air-textured nylon 6.6 continuous-filament yarns. Optical magnification of the air-textured yarns enables the average loop sizes and frequencies to be measured. The experimental results are shown to be in general agreement with a suggested mechanism of the process, which argues that the initial filament twist in the parent yarn redistributes itself as snarled loops and that the overfed yarn contributes to the size of such loops; the deflexion of filaments by air-drag forces is also shown to make a contribution to a looping effect, which can be estimated theoretically. Increasing the yam overfeed increases both the loop size and the loop frequency. Increasing the yam pre-twist decreases the loop size and increases the loop frequency. Increasing the air-pressure also decreases the loop size and increases the loop frequency. Experimental and theoretical results are in general agreement. As would be expected, the only processing condition that effects a change in linear density is the overfeed, but all the processing conditions that have an effect on loop dimensions also have an effect on the change in volume, i.e., on the physical bulk. Overfeed is the greatest single contributor to physical bulk, since both loop size and loop frequency increase with overfeed, occluded air spaces being thereby created in yarn and fabric form; conversely, with varying twists and air-pressures, the effects of decreasing loop size and increasing loop frequency are to some extent self-balancing in their contribution to physical bulk. It is shown how the various processing parameters affect the stability of air-textured yarns. Textured yams produced from parent yarns possessing small amounts of pre-twist have a high instability because of the lack of binding twist for securing the entangled structure. Increasing the overfeed greatly increases the number and size of loops, and this causes greater instability. Increases in the applied air-pressure also increase the yarn instability. Two new mechanical techniques have been devised to measure the yarn instability, and these have been found to be greatly superior to the stability-testing apparatus normally used, which has serious defects from the viewpoint of accuracy. The tenacity of the air-textured yarns tends to decrease for increasing values of all the main processing variables considered. Increasing the yarn pre-twist tends to reduce the percentage elongation at break, but independent increases in the supply-yarn overfeed and the applied air-pressure both tend to increase this characteristic. These results are interpreted in the light of the bulking mechanism previously postulated. [ABSTRACT FROM AUTHOR]

The theory of the extension of continuous-filament yarns is re-examined by means of energy methods and presented in much simpler terms than those previously given. The essential statement of the theory is contained in four equations, which can be used as a basis for numerical computation. The limitations and possible generalizations of the theory are discussed. [ABSTRACT FROM AUTHOR]

This paper describes laboratory experiments designed to show what improvements can be achieved in the properties, particularly the modulus, of ICI nylon 6.6 tyre cords. The experiments fall into four groups: (i) hot-stretching tyre cords under conditions more severe than those conventionally used, up to the maximum temperatures and tensions possible; (ii) as in (i), but using cords made from hot-stretched yams; (iii) as in (i), but using twist levels lower than the conventional ones; (iv) as in (iii), but using cords made from hot-stretched yams. [ABSTRACT FROM AUTHOR]

The article offers information on polyester microfibers as the new microfiber technology. According to the author, polyester microfibers can be used for the creation of fashionable apparel for women, with a new hand, and smooth drape. Microfibers could produce sophisticated fabrics, but could pose a challenge for the textile dyer, and finisher. It discusses definition and features of microfibers, and the processes for polyester microfibers which include finishing process, dyeing, and desizing or washing.

A kind of patented spinning technique called wool, filament and spandex three for one spinning technique was introduced in this article. It was achieved through modifying the traditional wool ring spinning frame by adding filament and spandex feeding device. This made it possible to produce wool stretch yarn with filament and spandex at one time. It mainly introduced the principle of yarn resultant, spinning process, key points in production and the physical testing results of the yarns in three different yarn size. The yarn was used to develop wool stretch fabric. The finishing technique and the fabric style was discussed as well. [ABSTRACT FROM AUTHOR]