33—WITHDRAWAL FORCES IN THE PROCESSING OF WOOL SLIVERS: PART I: THE DETERMINATION OF WITHDRAWAL FORCE

Apparatus is described by means of which the force necessary to withdraw a tuft of fibres from a sliver inserted in pins can be measured. An account is given of the use of this apparatus in investigations of withdrawal-force variations for different sliver weights and withdrawal speeds.     

44—THE INFLUENCE OF COTTON-SPINNING MACHINERY ON THE RANDOM IRREGULARITY OF SLIVERS AND YARNS PART II: EXPERIMENTAL INVESTIGATIONS

The experimental procedure is described, special attention being given to the influence of the measuring system. The results are given of measurements at the drawframe, speedframe, ring-spinning machine, and open-end rotor-spinning machine.     

31—INTERACTIONS BETWEEN ALKYLSULPHATES AND CATIONIC SHRINK-RESIST RESINS FOR WOOL PART II: THE INFLUENCE OF VARIOUS ALKYLSULPHATES ON THE SHRINKAGE OF KNITTED WOOL FABRICS

A study of the effect of the aggregates formed between Hercosett and alkylsulphates (C₈–C₁₄) in preventing the shrinkage of wool samples pre-treated with methylamine and hydrogen peroxide is reported. The amount of surfactant adsorbed on each pre-treated wool sample was estimated, and a mechanism by which the aggregate exhausts on the fibre is suggested.     

12—RESIDUAL GREASE IN THE GILLING AND RECTILINEAR COMBING OF MERINO WOOL

In gilling and combing, there is an optimum level of residual grease, which gives a top with the lowest percentage noil and the highest mean fibre length. It is shown that, if the residual grease of the scoured wool could be held at approximately 0.8%, there would be little to be gained by the addition of a combing oil.     

30—THE INFLUENCE OF ORIGIN ON THE STRESS–STRAIN RELATIONS OF WOOL FIBRES

Stress–Strain data for wool fibres of different origin are presented, the tests having been made under different moisture conditions. Small differences exist between wool fibres from primary and secondary follicles from the same animal, the secondary being easier to stretch both initially and finally under wet conditions. However, the relative yield slope is markedly higher for secondary than for primary fibres. Differences exist between and within breeds in the initial modulus, the stress at 15% extension, and the slopes of the curves in the yield and post-yield regions.     

38—THE INFLUENCE OF WIRE PROFILE ON THE QUALITY OF WOOL-TYPE CARDED WEBS. PART II: NON-CONVENTIONAL FLEXIBLE WIRE

This paper describes a series of carding experiments in which non-conventionally shaped flexible card teeth, with the leading edge of the tooth made narrower than the following edge, in contrast to conventionally shaped teeth, in which the leading edge is wider than the following edge, were used to assess the nep content and fibre breakage of webs made from 70s lamb's wool containing known amounts of cut woollen and worsted threads.

It is demonstrated, both theoretically and practically, that this new conception of card-wire profile will give less neppy webs for the same production rate than those produced by using conventionally shaped teeth. It is also shown that the new type of card wire leads to greater carding power, measured in terms of thread removal, with no increase in fibre breakage.     

22—STUDIES ON THE NOBLE COMB. PART I: THE INFLUENCE OF CIRCLE TEMPERATURES

The combing performance of the Noble comb is dependent on the withdrawal force of the ingoing slivers, the setting of the drawing-off rollers, the absolute temperatures of the small and large circles, and the quantity of ether-extractable matter present. The withdrawal force has the greatest effect on the production of minimum noil and is also a major factor in the selection of the optimum temperatures to be used at any given setting. A theory of fibre selection and fibre migration is presented in order to explain the experimental conditions characterizing minimum noil. It is shown that changes in mean fibre length sometimes conflicted with changes in percentage noil. Certain modifications to the comb were made in order that the combed slivers from the small and large circles could be separated.     

47—THE EXTRACTION OF WATER FROM COTTON-YARN PACKAGES BY CENTRIFUGAL FORCE. PART II: THE DISTRIBUTION OF MOISTURE IN AXIAL SPINNING

In the axial drying of packages, there are significant differences of centrifugal field between the inside and outside of the packages. These may give rise to differences in moisture retention. Of far greater importance, however, is a zone of high retention, which lies near the outside surface of the package.     

56—THE WRINKLING BEHAVIOUR OF WOOL FABRICS: THE EFFECT OF THE STRUCTURE OF FORMALDEHYDE CONDENSATION POLYMERS ON THE STABILIZATION OF ANNEALED WOOL

An investigation is reported of the use of formaldehyde condensation polymers of aromatic amines, heterocyclic amines, and phenols to stabilize the improved wrinkle-recovery of annealed wool. These polymers were formed in situ during the annealing process.

The most effective polymer networks were those obtained from the reaction of formaldehyde with multifunctional compounds such as (i) 2,4,6-triaminopyrimidine, (ii) 2,6-diaminopyridine, (iii) 3,5-diamino-1,2,4-triazole, (iv) 1,3,5-trihydroxybenzene, (v) 1,3-dihydroxybenzene, and (vi) 2,4,6-triamino-s-triazine.     

67—THE INFLUENCE OF WIRE PROFILE ON THE QUALITY OF WOOL-TYPE CARDED WEBS. PART III: THE ASSESSMENT OF CARD-WIRE SHARPNESS

This paper is concerned with a technique for assessing different degrees of sharpness between flexible card-wire teeth. An Instron Tensile Tester was used to measure the force required to pull strips of granular-faced material over card teeth that differed in both sharpness and density, both ‘with’ and ‘against’ the wire points. Variants introduced included the load applied by the granular material to the teeth and the grit size of the granular material.

It is shown, on the basis of experiments on five different densities of card clothing, each ground to three different degrees of sharpness, that these differences can be quantitatively detected when they are measured against the wire points and that they are in complete agreement with the subjective assessments of wire sharpness.

It seems possible that the principles enunciated in this paper may be used to devise an instrument for detecting differences in wire sharpness.     

19—THE MEASUREMENT OF TORQUE IN CONTINUOUS-FILAMENT YARNS. PART II: THE EFFECT OF YARN TENSION

The yarn torque developed by the applied tension in the torsion-balance apparatus described in Part 1 of this series is calculated by using an expression derived in an earlier paper. Differences in shape of net-torque–twist curves are studied for nylon monofilaments and model plied yarns; these differences in shape are related to friction effects and to the mechanical properties of the constituent filaments. The torsional rigidity of the yarns is evaluated from the initial slope of the torque–twist curves for a series of nylon monofilaments; the torsional rigidity and torsional modulus are also calculated from the load–extension curve of a closely wound helical spring by employing the classical theory of elasticity.     

6—THE INFLUENCE OF WIRE PROFILE ON THE QUALITY OF WOOL-TYPE CARDED WEBS. PART I: CONVENTIONAL FLEXIBLE WIRE

This paper is concerned with the influence of the clothing of the various parts of a card, i.e., the swift, workers, and doffer, with varying degrees of sharpness, on the nep and thread contents and fibre breakage of card webs of 70s lamb's wool containing known amounts of cut woollen and worsted threads. The rollers of the experimental card were covered with 115/10½/31 round flexible card wire. The teeth were sharpened by both surface- and side-grinding techniques.

It is shown that the efficiency of carding varies with the sharpness of the card teeth but that the conditions of the doffer and worker wires are more important than those of the swift, although the swift–doffer relationship is critical to the success of the carding process. It is also evident that the technique of achieving a certain sharpness, i.e., by surface- or side-grinding, affects the clarity of the resulting web. Furthermore, card rollers function more efficiently when their teeth profiles are similar to each other.     

2—PERMANENT-PRESS EFFECTS IN WOOL: PART V: METHODS OF STABILIZING SET

Shrink-resist wool set in the normal way can lose wanted set or acquire unwanted set during machine-washing and tumble-drying because the molecular-bond rearrangements responsible for setting can still occur during the laundering cycle. The set can be stabilized to withstand such laundering by any of the following methods:

1. the inhibition of thiol-disulphide interchange by:

   1. removing ionized thiol groups, or

   2. converting disulphide bonds to non-interchangeable links, such as —S—, —SCH₂S—;

2. the introduction of new cross-links; or

3. denaturation to form structures that are slow to rearrange during washing.

The stability of set is enhanced by a combination of the methods because these operate by different mechanisms. Prevention of thiol-disulphide interchange appears to be more important during washing, whereas the presence of cross-links appears to be more important to aid recovery during tumble-drying.     

18—AN APPLICATION OF MINI-COMPUTERS TO THE OPTIMIZATION OF THE OPEN-END-SPINNING PROCESS PART IV: THE INFLUENCE OF WINDING TENSION ON YARN PROPERTIES

The winding tension and package mass can affect the characteristics of rotor-spun yarns. The properties most affected are the elongation at break and yarn imperfections, particularly thick places, so that the yarn irregularity is also affected. Increases in winding tension above a given value reduce the yarn quality quite independently of the package mass. When the winding tension is low, however, this mass exerts some influence, the yarn quality deteriorating as the package mass increases.     

27—THE NORMAL FORCE BETWEEN TWISTED FILAMENTS: PART II: EXPERIMENTAL VERIFICATION

In a previous paper, the importance of lateral pressure in the tension and bending behaviour of yarns was discussed; a theoretical model, which included the effects of bending and torsional rigidities as well as the tensile, shear, and frictional forces, was proposed, and expressions for the lateral pressures were derived. In this sequel, the experimental verification of the previously derived expressions has been carried out on a very simple twisted structure, consisting of two rubber strands. The results obtained support the theoretical predictions of the lateral pressure for the experimental model and lead to the conclusion that, for filaments with significant torsional and bending rigidities, lateral pressures are obtained in the yarn even when there is no significant tension on the individual filaments. An approximate scheme for estimating the lateral pressures in an idealized, close-packed, multilayered continuous-filament yarn is proposed as an extension of the above results.     

25—COMPOSITION TOLERANCES IN THE MANUFACTURE OF TWO-COMPONENT TEXTILE FABRICS PART II: THE CONTROL OF COMPOSITION VARIATION IN TEXTILE MANUFACTURE

Aspects of the manufacturing technology of two-component fabrics are considered in the light of statistical methods developed in Part I. Quite small design errors increase failure rates significantly; the nominal composition should always be based on actual analyses of intermediate and final products.

Many textile fabrics, especially those containing blended staple-fibre yarns, will not conform consistently to a specified tolerance of ±3 percentage units when tested by the analysis of a single sample or garment; a tolerance of ±5 units is technically realistic for well-made fabrics. A ±3-unit tolerance can reasonably be met by a statement of the average composition of a production batch.

It may therefore be concluded that the EEC Directives, in their mandatory specification of composition labelling, sampling, analytical methods, and tolerances, are unrealistic, since their requirements are not industrially achievable by many textile manufactures.     

34—THE CONTROL OF THE SHAPE AND DIMENSIONS OF KNITTED WOOL FABRICS

An account is given of an investigation of the use of steam treatments as a means of controlling the shape and dimensions of plain-knitted wool fabrics, firstly by allowing the fabric to relax towards its dimensionally stable state during steaming and secondly by steam-setting the fabric while it is held at a predetermined width. This steam-setting procedure is compared with two permanent-setting treatments for wool—a chemical-setting treatment and setting in boiling water.

Of the two methods of producing a dimensionally stable fabric, namely, by relaxation and by setting, the relaxation method is by far the more effective. The most important result of this work is that knitted wool fabrics—whether unset, steam-set, or permanently set—will always approach their completely relaxed shape and dimensions after only a couple of minutes' gentle agitation in water. It is concluded that conventional methods of shaping knitted wool fabrics and garments, which rely principally on steam-setting the fabric or garment to a size and shape different from its relaxed size and shape, are not likely to produce garments that have good dimensional stability and good shape-retention properties.

The ineffectiveness of permanent-setting agents in producing dimensionally stable knitted garments is contrasted with the relative effectiveness of these agents in producing pleats and permanent creases in wool cloths. This difference in behaviour is explained in terms of the different levels of individual fibre strains involved.     

25—INCREASING THE RATES OF FABRIC PRODUCTION OF WEFT-KNITTING MACHINERY: PART III: MEASUREMENT OF THE NEEDLE FORCES

When information is required about the forces acting on the needles in different cam systems, it is clearly more desirable to measure these forces directly than to measure the over-all machine torque.

This paper describes a method for measuring the needle forces directly, and an examination is made of some of the information obtained from the force-measuring device used.     

42—THE ESTIMATION OF CROSS-LINKS IN WOOL FROM THE EXTENT OF SWELLING IN FORMIC ACID

An account is given of the application of a gravimetric method for measuring the extent of swelling of wool in formic acid to a series of wool samples containing decreasing amounts of randomly distributed disulphide bonds. In accordance with the Flory-Rehner equation, a linear relation was observed between disulphide content and V 5/3, where V is the volume of dry wool expressed as a fraction of the volume of swollen wool. This calibration curve was then used in conjunction with swelling data to assess the number of cross-links introduced on the treatment of wool with formaldehyde and other bifunctional reagents. The method is particularly useful for ranking in order relatively high levels of cross-linking.