57—THE DEGREE AND STABILITY OF FLAT-SET IN WOVEN COTTON FABRICS

The determination of Fabric flat-setting by measurement of the bending recovery at low and medium curvatures, before and after wet treatment, is discussed. The degree, stability, and rating of flat-set obtained by the use of a Shirley bending-hysteresis Tester are described. Comparisons are made with visual assessments based on fabric replicates and with other objective assessments, such as crease-recovery.     

21—THE WIRA SHOWER TESTER: A NEW INSTRUMENT FOR THE QUALITY CONTROL OF FABRICS

A new instrument for measuring the absorption and penetration-resistance of fabrics is described. It is based on a novel method of drop propagation, and it is shown that the dynamical properties of the drops lie within the wide range of values provided by natural rain. The test procedure, which is intended to form the basis of a draft British Standard method of test, is described. Results of tests on a variety of apparel fabrics are given, and these include comparative tests on unproofed and treated cloth and tests on fabrics of known wear performance.     

21—THE ACETYLATION OF COTTON

An account is given of a study of the effect of the amount of activating agent, the temperature, the catalyst, and the diluents used in the acetylation of cotton with perchloric acid as catalyst. Sulphuric acid was compared with perchloric acid as a catalyst. The effects of traces of water, the amount of acetyl chloride, and the rate of acetylation were studied in the acetylation of cotton with acetyl chloride and pyridine. The conditions in all cases were such that the acetylated cotton retained its fibrous form.     

32—THE SURFACE ABRASION OF COTTON FABRICS AS SEEN IN THE SCANNING ELECTRON MICROSCOPE

Experiments are described in which cotton fabrics at different stages of chemical processing were abraded to different extents on a Wira Abrasion Tester with three different abradants, namely, a smooth paper, a similar paper with a rough unfinished surface, and a standard worsted fabric. The three different plain-weave cotton fabrics selected were (a) desized and scoured, (b) bleached and mercerized, and (c) dyed and resin-treated. Scanning electron microscopy revealed that progressive chemical finishing, especially resin-finishing, reduced the abrasion-resistance of these fabrics. The rate of attrition of the cellulosic material at the surface of the fabric was much faster for rough paper than for a smoother type of paper abradant. The crossbred-worsted abradant was less severe than paper in its abrasive action. It also produced, in general, a more fuzzy fabric surface, with several loose fibre ends on the surface. Resin-treated fabrics had fewer of these loose surface fibres than the other two samples, particularly the scoured fabric, which had the most. In the resin-treated fabric, the abraded single fibre ends did not exhibit any twisting, whereas this characteristic feature was rather extensive in the non-resin-finished samples. The lack of twisting and rolling of the fibres probably arose from the constraints imposed by the resin crosslinks, which made the fibres more rigid and caused them to tend to fracture or rupture sharply rather than fibrillate over a somewhat extended length.     

BPERSIST IN THE STRATEGY OF QUALITY ANDFAMOUS BRAND TO PUSH THE DEVELOPMENT OF LEATHER INDUSTRY TO A

ＰＥＲＳＩＳＴＩＮＴＨＥＳＴＲＡＴＥＧＹＯＦＱＵＡＬＩＴＹＡＮＤＦＡＭＯＵＳＢＲＡＮＤＴＯＰＵＳＨＴＨＥＤＥＶＥＬＯＰＭＥＮＴＯＦＬＥＡＴＨＥＲＩＮＤＵＳＴＲＹＴＯＡＮＥＷＬＥＶＥＬ（ＣｈａｉｒｍａｎｏｆｔｈｅｂｏａｒｄｏｆＣｈｉｎａＬｅａｔｈｅｒＩ...     

18—THE PREDICTION OF STRIPINESS DUE TO ROGUES IN KNITTED FABRICS

A group of adjacent rogue threadlines in a knitted fabric is likely to be visible as a stripe when the fabric is dyed. This paper provides theoretical results (which are also presented graphically) that give the probability of two or more, and of three or more, rogues occurring together in fabrics of various widths for varying proportions of rogues in the threadline population.     

32—THE WEATHERING OF COTTON,NYLON, AND TERYLENE FABRICS IN THE UNITED KINGDOM

It is well known that textile fabrics lose strength when subjected to unprotected outdoor exposure, and the amount of strength lost for a given period of time, or for a given number of sun-hours as measured by the Campbell-Stokes apparatus, may vary considerably according to the nature of the fibre and to the climatic conditions prevailing at the exposure site. From data recorded at eight exposure sites in the United Kingdom during 1961 and 1962, it is possible to draw certain conclusions. Thus, in rural areas, such as Pontypool (Mon.), Invergowrie (Perth), and Carlton (Durham), where ‘clean’ or unpolluted atmospheres might be expected to exist, an 11-oz/yd² cotton duck was found to be more resistant than either a 10½-oz/yd² nylon or a 14-oz/yd² Terylene fabric. In semi-rural areas, such as Lanark and Farnborough (Hants.), 11-oz/yd-²; cotton duck appeared to be as resistant as Terylene. It was only in urban areas, such as Didsbury and Droylsden (Lanes.) and Bradford (Yorkshire), that cotton was found to be inferior to Terylene and to a less extent to nylon. The 16-oz/yd² cotton fabric was found to be more resistant than the 11-oz/yd² one.     

15—EXPERIMENTAL STUDIES OF THE DIMENSIONAL PROPERTIES OF EYELET FABRICS. PART I: THE DIMENSIONAL PROPERTIES OF CLOSE-EYELET COTTON FABRICS

The geometrical parameters of the eyelet structure are related to its loop length in both the dry- and the wet-relaxed states. The effects of the structural characteristics of the stitch on its dimensional properties are discussed. Formulae relating the weight per square yard and weight per running yard to the loop length are given and confirmed experimentally.     

18—A COMPUTER TECHNIQUE FOR ANALYSING THE CAUSE OF IRREGULAR PICKSPACING IN WOVEN FABRICS

A method for determining the cause of irregular pickspacing is described which is applicable in cases where there is a significant variation in weft count, particularly when there is no obvious correlation between weft count and pick-spacing. The method makes use of an electronic computer. The paper also draws attention to the significance of sample size in the experimental determination of weft count and pickspacing.     

33—THE STRENGTH OF COTTON FIBRES AND THE DEGREE OF DEVELOPMENT OF THE SECONDARY WALL

A comparative analysis of two methods of determination of the maturity of cotton fibre is reported. One consisted in comparing fibres with reference drawings and the other in using the polarizing microscope. The relationship between the degree of development of the secondary wall determined by these methods and the strength of cotton as one of its most important physical properties was also taken into consideration.

The degree of correlation between the methods discussed and between the results obtained with them and the breaking load was found.

It was also ascertained that the degree of maturity was not the same throughout the length of the fibre. It increased from the base to the tip of the fibre.     

11—THE DYNAMICS OF THE FALSE-TWIST PROCESS PART V: RESPONSE TO VARIATIONS IN FEEDSTOCK

The theory is extended to deal with the frequency response of texturing variables to variations, both actual and latent, in the feedstock linear density. Experimental measurements of the response made by using feedstock with controlled variation are compared with theoretical predictions, and conclusions are drawn about their relevance to textured-yarn quality.     

12—AN ENERGY METHOD FOR CALCULATIONS IN FABRIC MECHANICS PART II: EXAMPLES OF APPLICATION OF THE METHOD TO WOVEN FABRICS

In the preceding paper, an energy method for performing calculations in fabric mechanics, together with appropriate computational techniques, was described. The present paper contains examples of applications of this method to woven fabrics, particularly to various models of plainweave fabric subject to tension, but also briefly to fabric-bending and to other weaves.     

28—THE PRODUCTION OF WEFT-STRETCH COTTON FABRICS BY SLACK MERCERIZATTON

In the production of weft-stretch fabrics by slack mercerization, weft shrinkage was assisted by the application of high warp tension during mercerization and washing. The addition of a polyethylene lubricant to the post-mercerization resin bath reduced the warp stiffness of the fabric and slightly improved its stretch, performance. At specific warp and weft cover factors, plain weave gave a better stretch performance than twill weaves, although the differences were less than expected. The choice of finer weft than warp yarn facilitated the development of weft crimp. Unless the weft yarn spacing was adequate, however, the weft crimp could not be fully utilized on stretching, because of jamming of the fabric structure during crimp interchange.     

12—THE INFLUENCE OF FINISHING AND WASHING TREATMENTS ON THE DEGREE AND STABILITY OF FLAT-SET IN WEFT-KNITTED COTTON FABRICS

The effects of different washing and drying relaxation treatments, of increasing severity in terms of time, temperature, and agitation (mechanical action), on the couple–curvature and dimensional characteristics of variously finished weft-knitted cotton fabrics are described. The influence of relaxation and consolidation on the degree and stability of flat-set is discussed.     

19—AN APPLICATION OF MINI-COMPUTERS TO THE OPTIMIZATION OF THE OPEN-END-SPINNING PROCESS PART XI: THE OPTIMIZATION OF THE OPENING-ROLLER SPEED AND TWIST FOR PROCESSING CONDITIONS REMOTE FROM THE OPTIMUM DURING THE ROTOR-SPINNING OF COTTON YARNS

The optimum values for both the opening-roller speed and the yarn twist, in operating with near-extreme values of both the total draft and the rotor speed, are studied. These values of draft and speed are, nevertheless, not uncommon in industry. For a total draft of 173 and a rotor speed of 45 000 r/min, and with a Süssen Rotorbox machine, it was found that the optimum values of yarn twist and opening-roller speed did not coincide with each other when either the yarn regularity or tenacity was considered as the most important parameter, a phenomenon that had, in fact, been observed earlier when all the operating parameters were optimized. In this instance, the best quality indices are obtained for opening-roller speeds above 6000 r/min and twist multipliers, a, of about 160 for a 23.57-tex yarn (N _e = 25).     

23—A THEORETICAL ANALYSIS OF THE TENSILE PROPERTIES OF PLAIN-KNITTED FABRICS. PART I: THE LOAD-EXTENSION CURVE FOR FABRIC EXTENSION PARALLEL TO THE COURSES

An investigation is described in which, by means of a two-dimensional model of the plain-knitted structure, load-extension curves for extension in the course direction were calculated theoretically. It was assumed initially that the only mechanism of fabric extension was elastic deformation of the loop shape. Account was taken of setting of the yarns into the relaxed-loop shape, but this was found not to have any significant effect on the theoretical load–extension curves. It was found that the intial portions of these curves were almost linear but that the slope could be greatly affected by the occurrence of lateral yarn compression. When yarn compression was taken into account, good agreement was obtained with experimental results for a nylon-monofilament fabric and a series of wool plain-knitted fabrics.     

26—THE ELASTIC RESISTANCE TO BENDING OF PLAIN-WOVEN FABRICS

The elastic resistance to bending of woven fabrics has previously been considered in terms of the existence in the yarns of rigid and elastic sections. The difficulties inherent in such a model and the noticeable differences between the predicted and experimental findings are examined in this paper. Two models of a plain-woven fabric in which the yarn cross-sections are incompressible are then analysed theoretically to obtain the predicted relationship between the applied couple and the curvature of the fabric.

In the first model, the yarns are considered to be unset, i.e., if released from the fabric, they would be uncrimped, and in the second model they are considered to be completely set, i.e., if released from the fabric, they would retain all their crimp. The predicted bending resistance does not agree with the behaviour of actual fabrics owing to the difficulty of defining the ‘radius’ of the yarn in the fabric, but many puzzling qualitative aspects of the bending behaviour of woven fabrics are, as a result of the analysis given, satisfactorily explained.     

8—THE SHEARING OF FABRICS: A NOVEL APPROACH

A method is described for measuring some of the shear properties of fabrics, a square test piece in cyclical biaxial extension being used. Shear stiffness and ‘coercive force’ may be quantified and other features of the hysteresis curve studied qualitatively.     

28—A THEORETICAL ANALYSIS OF THE TENSILE PROPERTIES OF PLAIN-KNITTED FABRICS. PART II: THE INITIAL LOAD-EXTENSION BEHAVIOUR FOR FABRIC EXTENSION PARALLEL TO THE WALES

A theoretical analysis is made of the load-extension behaviour of plain-knitted fabrics for the case in which extension takes place parallel to the wales. The analysis is performed by examining the deformation of the three-dimensional loop shape, this shape having been described in a previous paper. The calculated values of the initial tensile modulus are compared with those obtained experimentally from a series of wool fabrics. The theoretical values are lower (though of the correct order of magnitude) than the experimental values; this effect is explained by frictional resistance to yarn slippage.     

26—AN INVESTIGATION OF THE TAPER OF COTTON FIBRES PART V: DIFFERENTIAL FRICTION IN COTTON FIBRES

This paper reports the results obtained in a study of the frictional behaviour of root-tip-aligned fibre fringes under different levels of normal load. Experiments on eight cottons revealed that the coefficient of friction between the root parts was higher than that between tip parts. This difference in friction was significant at lower normal loads. The probable reasons for this behaviour are discussed in terms of area of contact and distribution of convolution angle and moisture content along the length of the fibre.