37—THE WRINKLING AND BENDING OF FUSIBLE INTERLININGS

A series of apparel fabrics were bonded both to a cotton base cloth and to a worsted base cloth. The fabrics were then wrinkled by the AKU tester under wet and standard atmospheric conditions, and their wrinkle severity was determined by means of the Sivim Wrinklemeter. Buckling and cantilever tests were also made, and the wrinkling behaviour and bending performance were compared.     

24—THE BENDING BEHAVIOUR OF PLAIN-WEAVE FABRICS WOVEN FROM SPUN YARNS

The bending behaviour of square plain-weave fabrics spun and woven from nineteen different fibres, each in a range of cover factors, has been studied. It is shown how this behaviour is determined by the mechanical properties of the fibre and the frictional and geometrical restraints within and between yams in the fabric. The effects on these restraints of cover factor and of relaxation in wet finishing and in heat-setting are examined. Factors affecting cloth stiffness are summarized, and it is shown that two quantities, an elastic component and a frictional component, are required to specify the bending behaviour with reasonable completeness.     

28—THE BENDING AND CREASING OF MULTICOMPONENT VISCOELASTIC FIBRE ASSEMBLIES. PART II: THE MECHANICS OF A TWO-DIMENSIONAL ASSEMBLY OF LONG STRAIGHT FIBRES OF DIFFERENT TYPES

A model two-dimensional assembly of long straight viscoelastic fibres of many different types arranged in various directions is analysed in terms of bending, creasing, and associated recovery behaviour. The fibres are assumed to be viscoelastic in both bending and torsion and subject to frictional restraints in both these modes of deformation. It is assumed that the model is relevant to the bending and creasing behaviour of woven and non-woven fabrics composed of fibres of one or more types.     

27—THE BENDING AND CREASING OF MULTICOMPONENT VISCOELASTIC FIBRE ASSEMBLIES. PART I: GENERAL CONSIDERATION OF THE PROBLEM

The problems involved in making a mechanical analysis of bending deformations in textile fabrics are discussed. It is suggested that progress can be made by making simplifying assumptions concerning the geometry of fabric structure and deformation and using energy considerations to calculate forces and moments. Certain simple examples are given of the usefulness of this approach. A foundation is laid for the construction of a computer model that will, it is hoped, simulate the viscoelastic bending and creasing behaviour of textile fabrics from a knowledge of the bending and torsional viscoelastic properties of the constituent fibre(s) and their relative geometrical arrangement.     

The Effect of Environment on the Flexural Rigidity of Woven Fabrics

The concept of fabric engineering—the design of fabrics with predetermined physical properties—is used in relation to the structure of woven fabrics, and it is shown from theoretical considerations, with the aid of computer analysis, that a large discrepancy exists between the number of weaves of comparatively small size that can be woven and the number that are actually produced. Experimental results obtained on fabrics woven in accordance with a particular plan indicate that the weave has a very marked effect on both tearing strength and stiffness. The results further suggest that weave modification can provide a means of obtaining very accurate control of the two properties investigated and of their possible combinations, and the same may well be true of other physical properties of fabrics.     

Problems of Protection and Comfort in Modern Apparel Fabrics

An investigation is reported in which the shrink-resistance of wool treated by exhaustion with Synthappret BAP and magnesium chloride was improved by the introduction of a strongly alkaline treatment immediately before or after the polymer-application step. The greatest improvements were observed with pre-treatments at around pH 11 or with after-treatments at around pH 10. After-treatments gave a greater improvement. The improved shrink-resistance was attributed to the promotion by alkali (in the bath, or carried over on the fibres) of reactions of the carbamoyl sulphonate groups in Synthappret BAP with themselves (cross-linking) or with the fibre.

Alkaline pre-treatments were considered to be more practical than after-treatments. They could be simply incorporated into the normal Synthappret BAP–magnesium chloride exhaustion-processing sequence by a change from a neutral or mildly alkaline scour with non-ionic detergents to a preliminary scour with sodium carbonate or metasilicate solution at pH 11.

Alkaline pre- and after-treatments were examined with a range of other exhaustion shrink-resist finishes for wool based on polymers the only other case to show improved shrink-resistance was the batch Hercosett 125 treatment of chlorinated wool, and that only at low chlorination levels. In a comparison of a selection of exhaustion shrink-resist treatments on untreated wool, the most effective (for the amount of polymer applied) on the fabrics studied was Synthappret BAP—magnesium chloride coupled with an alkaline after-treatment.     

6—THE WEAR LIFE AND ABRASION-RESISTANCE OF CARPETS MADE FROM VARIOUS FIBRES AND BLENDS

An account is given of a study of the wearing properties of woven and tufted carpets made from wool, nylon, viscose rayon, and an acrylic fibre and from various blends of these fibres. The carpets were subjected to trials on two staircases and to laboratory tests for resistance to abrasion.

It is shown that nylon resisted abrasion in use better than the other fibres studied, and the advantages of introducing nylon into a blend with one of the other fibres are demonstrated by comparison with the results obtained on carpets made entirely from the other fibres.

It is also shown that, in general, the laboratory abrasion tests confirm the ranking of the carpets in the service trials on a staircase, although the advantages of introducing nylon appear to be greater in the laboratory tests than in use.     

22—A THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE CREASE RECOVERY OF PLAIN-WEAVE FABRICS WOVEN FROM STAPLE YARNS

The retained angle at a crease is considered to be made up of two components: inelastic and frictional. A theoretical scheme has been developed that enables the inelastic component to be calculated from the appropriate fibre, yarn and fabric data and the calculations are illustrated for three fabrics.

An experimental investigation of the crease-recovery behaviour of these fabrics, in conjunction with the calculations described above, has established a method of deducing the frictional component from the low-curvature bending-recovery behaviour of a fabric, and it is thus possible to make an estimate of the fabric crease-recovery angle. The calculation has been carried out for a range of fabrics woven from eighteen fibre types, each in four different cover factors, and the results are shown to agree reasonably well with the measured crease-recovery angles for the same fabrics. The experimental results are discussed and some interesting relationships are pointed out; in particular it is shown that fabrics must be well relaxed if the full potential of a high-recovery fibre is to be realized.     

The Air-permeability Measurement of Open Fabrics by Using Superimposed Fabric Layers

An account is given of an investigation of the dimensional properties of a series of plain weft-knitted fabrics produced from open-end-spun yarns. The results are compared with those for similar fabrics knitted from ring-spun yarns.

It is shown that fabrics knitted from the two types of yarn possess different properties and particularly that the amount of relaxation shrinkage observed in fabrics knitted from open-end-spun yarns is greater than that which occurs in fabrics knitted from ring-spun yarns. The aesthetic properties of fabrics made from open-end-spun yarns are inferior to those of fabrics made from ring-spun yarns, particularly with regard to a lack of stitch clarity and a somewhat harsher handle, although the latter effect is shown to be apparently unrelated to differences in the frictional properties of the two types of yarn.     

28—SOME FACTORS INFLUENCING PUCKERING AND COCKLING IN FULLY FASHIONED GARMENTS

A simple technique for the planning of rib cuffs and welts for fully fashioned garments that is based on the classical knitting geometry of plain and 1 × 1 rib fabrics is described. The effects of cover factor and some common loop ratios at the join of 1 × 1 rib and plain fabrics on puckering at the knitted join and the effects of cover factor and some yam characteristics on cockling in plain-knitted fabrics are given.     

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.     

18—THE ABRASION-RESISTANCE OF SOME WOVEN FABRICS AS DETERMINED BY THE ACCELEROTOR ABRASION TESTER

The use of an Accelerotor abrasion tester is discussed, and the abrasion-resistance of several plain-weave fabrics is shown to depend on the type of fibre. The materials are ranked in order of decreasing resistance to abrasion with carborundum, rubber, metal, and plastics abradants. Polyamide fibres have outstanding resistance and cellulose-ester and regenerated protein fibres poor resistance to abrasion. The order of resistance of other synthetic-polymer fibres, regenerated cellulosic fibres, and natural fibres is shown to alter slightly according to the nature of the abradant, the linear density of the fibre, and the sett of the fabric. The results are in general agreement with published data, but the resistance of polypropylene-fibre fabrics is lower than it was expected to be.

Microscopical examination of detritus confirmed that this consisted of small segments of complete fibre, which indicated that abrasion occurs by fibre breakage. A useful correlation is established between the specific strength and initial modulus of a fibre, or the energy of rupture of mechanically conditioned fibres, and the abrasion-resistance of a fabric.     

31—THE HANDLE AND BENDING BEHAVIOUR OF FABRIC LAMINATES

Certain aspects of the handle of fabric laminates are related to properties of the component fabrics. Particular attention is paid to a theoretical prediction of the bending stiffness of a laminate from the bending and tensile properties of its components. This theoretical stiffness is a minimum value; if, in practice, the observed stiffness is much greater than this, it may generally be assumed that excess of adhesive or of melted foam is the cause. The paper also reports work on other features of the bending behaviour, such as the degree of recovery from bending, and on the shearing behaviour. The work is concluded by a brief study of some faulty laminates.