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In any false-twist-crimping process, a heat treatment followed by a cooling treatment is given to the threadline in the twist zone in order to 'set' the inserted twist. The majority of commercial machines use metal contact heaters to heat the threadline, and cooling is achieved by exposure to ambient air. The data in this paper provide a basis for a simple method of calculating the temperature-time history of the threadline in the twist zone from the known yam and process parameters. Nylon 6.6 yarns were used for the major part of the work, but data are also presented for Terylene, Ulstron, Lycra, and glass-fibre yarns. The measurements cover wide ranges of the process parameters, i.e., linear density, twist, tension, surface temperature, and yarn velocity. [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 elastic properties of several polyurethane yarns and a natural-rubber filament have been measured. Part 1 of the paper deals with the behaviour of the materials in the condition in which they were supplied. In Part 2, the properties of the materials after thermal treatments at various temperatures within the range 20-220°C are presented and discussed. Thermal treatment is shown to have a pronounced effect on the stress-strain behaviour of the synthetic yarns, measured relative to their set dimensions, and on the retractive stress at a given extension. The elastic recoveries of the yarns are improved, their breaking extensions increased, and their strengths slightly decreased after thermal treatment. Relative to the synthetic yarns, thermal treatment has only a small effect on the elastic properties of rubber. [ABSTRACT FROM AUTHOR]

An account is given of an investigation of the influence of dry heat on wool keratin. It is shown by three different chemical techniques that cross-linking occurs up to a temperature at which the amino-acid decomposition becomes marked. Although Iysinoalanine and lanthionine are shown to be formed, these amino acids do not appear to be major contributors to the cross-linking of the heated protein. The covalent binding of the e-amino group of lysine was determined quantitatively, and, from the results obtained, it is deduced that this group is involved to a large extent in the formation of cross-links. On the basis of these findings, it is postulated that amide cross-links are formed through the ε-amino group of lysine by reaction with carboxylic side chains of aspartic or glutamic acids or their amide derivatives. [ABSTRACT FROM AUTHOR]

The section of "The Production and Properties of Nonwoven Fabrics" focuses on thermobonded fabrics. The use of thermoplastic fibres as bonding agents for nonwoven fabrics is discussed. Thermoplastic fibres are used in the manufacture of blankets, interlinings and wall-coverings. The thermobonded fibre is required to soften or melt at a lower temperature as compared to the fibres that form the main constituent of the web. Thermoplastic materials are processed by some form of heat treatment. This thermobonding process is applicable to fabrics containing binder or bicomponent fibres.

Heat treatment caused an increase in ductility. Aging caused an increase in strength and hardness with a decrease in ductility. Overaging caused decreases in strength and ductility. Solution treating resulted in a single phase. The precipitation of coherent intermetallic compounds caused maximum strengthening with minimum loss of ductility. [ABSTRACT FROM AUTHOR]

An account is given of experiments in which samples of wool fibres were heated in an oven for various times, and at different temperatures, and examined in a scanning electron microscope. Samples were also subjected to the Allwörden test and to a dye-absorption test. It is shown that, on exposure to dry heat, wool fibres retain their physical shape and characteristics, even under severe conditions, the only major change initially being discoloration. Only at temperatures of 160°C and above are serious physical changes, such as scale deformation and changes in X-ray-diffraction patterns, observed. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Ageing in Single Fibres," which was published in a previous issue.

A study of the recovery of single fibres from bending is reported for nylon, polypropylene fibre, Courtelle, and some carpet fibres. Most of the recovery takes place during the first hour, with further small increases for up to seven days. The effects of heat treatments both before and during bending are examined. Poor correlation between bending and tensile recoveries leads to a consideration of tensile and axial compressive effects. Further work is desirable on the latter aspect. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Basic Amino Acids in Heated Keratin," published in the previous issue.