Chemically assisted protein annealing treatment

Bleaching and dyeing; fluid treatment and chemical modification – Chemical modification of textiles or fibers or products thereof – Proteinaceous fibers

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Details

81275, 812751, 81281, 81276, D06M 1101, D06M 1152, D06M 1153, D06M 1154

Patent

active

059283831

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to a method for treating proteinaceous materials that contain disulfide or polysulfide bonds to improve their performance at high relative humidity and when wet. The present invention is particularly applicable to keratinous materials such as for example wool, wool with reduced crystallinity, mohair, regenerated protein, or mixtures thereof but is not limited thereto.
Wool is a composite polymer, consisting of water impenetrable, crystalline filaments embedded in an amorphous matrix that contains a high concentration of the amino acid cystine. The matrix is therefore highly crosslinked and occupies about 70% of the fibre volume. The hygroscopic nature of wool has also been attributed to the matrix regions. The amount of moisture present in a mass of fibres or a yarn or fabric is calculated as moisture regain. Moisture regain is the loss in weight of water upon bone-drying at 105.degree. C. as a percentage of the dry fibre weight. The normal method for determining these values involves weighing, bone-drying, weighing, and calculating. Moisture-regain varies with the relative humidity (r.h.) of the atmosphere to which the fibres are exposed. (FIG. 1). The mechanical properties of the fibers are critically dependent upon moisture regain. A glass transition temperature (T.sub.g) that is also sensitive to water content has been identified to occur in the matrix region of the wool fibre.
The glass transition temperature is the temperature at which the material changes from being in a state where it behaves as a glass, at temperatures below Tg, to being in a state where it behaves as a rubber, at temperatures above Tg. At relative humidities higher than about 90%, proteinaceous materials begin to absorb large amounts of water. It is believed to be the water absorption, especially the large amount at relatively high humidity which may cause proteinaceous materials to change from the "glassy" to the "rubbery" state. It is believed that this transition is accompanied by a deterioration in the performance of proteinaceous materials. For example, fabrics made from these materials will suffer from high hygral expansion and a deterioration in the mechanical properties for example modulus (see Table 1 for example), bending rigidity, drape, wrinkle recovery etc. as the water content increases. Many chemical treatments are known to reduce the water content at higher relative humidity (Eg. 4) but none are practical as they require treatment with large amounts of chemical or cause excessive damage to the material or result in an unacceptable colour change.


TABLE 1 ______________________________________ Relative Hookean Modulus as a Function of Relative Humidity for Wool Relative Modulus Relative Humidity (%) ______________________________________ 1.13 0 1.10 3.6 1.00 31.8 0.93 44.2 0.86 65.5 0.76 77.7 0.58 90.5 0.48 97.7 0.41 100 ______________________________________ desired geometrical configuration, have been and still are the subject of considerable study. Methods which have been used to improve the resistance of wool and cotton articles to wrinkling and creasing are described in UK Patent Specification 1299377 and 1326628. 1299377 describes a method for increasing the resistance to, and recovery from, deformation of a textile material, the process comprising subjecting the material to an annealing treatment by maintaining the material at a temperature within the range of 30.degree. C. to 120.degree. C. for a period of more than 20 minutes, while maintaining the regain of the fibres at a value corresponding to a relative humidity of from 60% to 95%. The increase in resistance to and recovery from deformation was attributed to the rearrangement of labile hydrogen bonds within the wool fibres to more stable (i.e. low energy) configurations under conditions of increased temperature and/or regain. Conditions of increased temperature and/or regain brought about rupture of strained hydrogen bonds and as the temperature and/or region are slowly reduced the hydrogen

REFERENCES:
patent: 3639098 (1972-02-01), Delmenico et al.
WPAT abstract No. 92-239558/29, Jun. 1992.
WPAT abstract No. 91-372437/51, Nov. 1991.
WPAT abstract No. 91-372433/51, Nov. 1991.

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