FR2847772A1 - Manufacture of hosiery with hypoallergenic properties uses low-friction yarns spun from hydrophilic natural or semi-synthetic fibres - Google Patents

Abstract

The procedure, especially for use in the manufacture of socks, uses carded or combed yarns with a low friction coefficient, spun from hydrophilic natural or semi-synthetic fibres, such as cellulose, cotton, silk, wool, linen or hemp, or mixtures of these. The socks are made to a design that is non-compressive at the tops or on the legs or feet, and they are coloured with one or more dyes that do not create sensitivity on contact or penetration of the skin. After dyeing and removing all dye that has not bonded chemically with the fibres the socks are dried and shaped. The non-compressive properties are produced by having an absorbed fibre length sufficient to obtain a stretch of over 40 per cent, and preferably over 50 or 60 per cent.

Description

NEW PROCESS FOR PRODUCTION OF KNITTED OR CROCHETED ARTICLES

THUS OBTAINED

  The present invention relates to the field of textile industry and in particular to that of footwear.

  Its specific purpose is the production of footwear, in particular socks, with low abrasion potential and free from allergy phenomena.

  It specifically relates to a process for obtaining footwear, in particular socks, which are not likely to cause allergy phenomena, characterized in that they are made from natural or semi-synthetic fibers forming yarns with a low coefficient of friction, maintaining an adequate length of absorbed yarn (LFA) which allows a necessary and sufficient extension of the width of the sock, by dyeing the yarns 1 5 or footwear items from selected dyes whose nature chemical is not likely to generate contact dermatitis, by rinsing said articles to remove residual dyes which are not chemically bonded to the fiber and finally drying and then forming the products.

  The manufacture of a sock is based on knitting yarns, one forming the outer surface of the sock, the other the vaning thread, forming the inner surface of the sock. These threads, of identical or different nature, have physicochemical properties which are not inert with respect to the skin. The induced irritations can be chemical or physical, even pathological.

  The physical irritations partly result from the surface condition of the yarn as well as from the quantity of LFA, [Absorbed Yarn Length] adopted during knitting, which determines the flexibility of the sock. These two parameters exert a mechanical action on the skin, the abrasive effect of which can be demonstrated by tests on synthetic skin. The physical irritations of the skin also arise from the thermal properties of the fiber. Due to their chemical nature, in particular their hydrophilic-lipidic nature, certain fibers favor an increase in the temperature of the foot and consequently the moistness of the skin. This phenomenon is the source of perspiration, the development of bacteria, and even the appearance of fungi. Each of these manifestations contributes to irritating the skin.

  Chemical irritation results from the presence of sensitizing molecules on the surface of the fiber. Chemical molecules, brought in by dyeing or various processes of finishing the thread or footwear, come into contact with the skin. Under the action of sweat, they can penetrate the epidermis and reach the dermis. Certain molecules that were originally inert, such as azo molecules, were then shown to be sensitizing due to the breakage of some of their chemical bonds. This contact or the penetration of coloring molecules explains certain aggressions of the skin, the clinical symptom of which may be of the eczema, itching, redness type.

  The manufacturing method of the invention overcomes these drawbacks by minimizing all of the irritating phenomena of the skin.

  1 5 It consists of: - reducing the irritation caused by the abrasive nature of certain yarns, by opting for yarns with a low coefficient of friction, - reducing the irritation caused by an overly compressive construction of the sock, by maintaining an adequate LFA allowing an extension of at least 20 40%, preferably at least 50% and better still more than 60% of the width of the sock at the ribbing, the upper and the sole, - reduce excessive sweating thanks to the use of sufficiently hydrophilic fibers, under which cotton, linen and in particular natural fibers, - reduce the risk of contact dermatitis formation by using non-sensitizing dyes, the property is determined using their formula by studying the toxicological nature of each of the chemical groups constituting the molecule. This study is completed by a validation test, according to the method of Marzulli Maibach, evaluating the irritant and sensitizing power of the dye in the pure state, - eliminating the risks of the formation of contact dermatitis caused by the presence of residual dyes not chemically bound to the fiber, increasing the number of rinses of the finished product after dyeing. The number of rinses depends on the color and the dye recipe. It is obvious that for a dark dye with a lower exhaustion, it will be necessary to have recourse to 2 or 3 additional rinses. For a lighter dye, the number of rinses will be lower.

  In the case of socks containing an elastic thread or filament, the invention consists in reducing the contact of the skin with synthetic threads or filaments, such as those derived from petrochemicals, by using a thread whose elastic core, generally in elastane, is wrapped with a thread with hydrophilic properties (such as cotton, linen and viscose) according to one of the processes existing in the textile industry while, on the contrary, proscribing the polyamide 1 0 traditionally used because of its properties hydrophobic.

  The hypoallergenic nature of the finished product is then verified by tests to assess the irritant and sensitizing power of the product, such as the method of Marzulli and Maibach (KLIGMAN AM The identification of contact allergens by human assay J. of 1 5 Investigative Dermatol 1996, 47, 393-409 - KLIGMAN AM, EPSTEIN W. Updating the maximization test for identifying contact allergens Contact Dermatites 1975, 1, 231-239 MARZULLI FN, MAIBACH HI 1974b The use graded concentrations in studying skin sensitizers: Experimental contact sensitization in man Food cosmet Toxicol 12: 219-227.

  Human patch tests, Proc. Sci. Sect. Toilet Goods Assoc., 19: 46-49.1953 MARZULLI F.N., 20 MAIBACH H.I. Contact allergy: predictive test in man. Contact Dermaties 1976, 2, 1-17 AUFFRANC J.C., BERBIS Ph. Predictive skin tests J. Med. Esth. and Chir. Dermatol.

  1986, 49, 39-42 - GROSSHANS E., FOUSSEREAU J. Complications and complexities of reading patch tests. Ann.Dermatol. Venerol 1983, 110, 509-268.

  The construction of the sock is done by knitting on a circular loom. It is also possible to design the knitting of the sock flat by then sewing or any other making operation.

  The materials used for knitting are yarns obtained from hydrophilic fibers, preferably of natural or semi synthetic origin such as cellulose fibers and in particular mixtures of several fibers.

  The method according to the invention is defined by the following methods, which are preferred or necessary for producing socks which do not have allergenic properties, by using a yarn with a low coefficient of friction, preferably carded or combed, and by making a construction. making it possible to obtain sock extensions equal to or greater than% at the level of the compression zones such as ribbing, upper and sole.

  When the product contains an elastic thread, the covering thread of the elastic core is preferably a cellulose fiber such as, for example, cotton. The core can be made of elastane or other elastic fibers such as dibutyl terephthalate (PBT) and polytrimethylene terephthalate (PTT).

  The method according to the invention is also characterized by the fact that the dye (s), used for dyeing the thread or the footwear, have a chemical formula which is not liable to cause sensitization phenomena on contact or after penetration into the skin.

  1 5 The footwear can be knitted either from dyed yarn or from unbleached yarn followed by dyeing. This second option will be preferred in order to rid the finished product, during the dyeing process, of the various sizing products deposited on the yarn in order to facilitate its passage through the knitting machine.

  The dyeing of the yarn or footwear is carried out by soaking after the addition of various additives necessary for its mounting on the fiber. One can also use direct acting dyes in the presence of activators or retarders of the rise of the dye.

  One or more additional rinses are then carried out, possibly after addition of soap. In the case of light colors, the number of additional rinses will be lower.

  A single rinse will generally suffice. In any case, the number of rinses will depend on the chemical nature of the dye and its dye behavior. The socks are then dried, for example in a tumbler type tumbler with or without air circulation. The socks according to the invention are subsequently formed hot and under pressure.

  The socks obtained according to the method of the invention are ultimately subjected to tests for verification of the non-allergenic nature, for example the Marzulli Maibach test. For this purpose, a sample of sock is taken and crushed to obtain a patch. This patch is applied to the skin, especially of healthy human volunteers.

  The tests showed the total absence of allergy phenomena on a large and significant batch of healthy volunteers.

  It goes without saying for a person skilled in the art that the present process can be applied to the production of other footwear than socks and in particular mid-socks, socks, knee-highs, tights and the like provided they are made of hydrophilic material and that they use one or more dyes of the type mentioned above.

  The invention further relates to non-abrasive and non-allergenic footwear obtained by the process according to the invention.

  1 5 The socks of the invention find a use in hosiery to provide protection, isolation and aesthetics of the legs. They are aimed at men, women, children, adolescents and babies. They can have a very extensive range of colors, being either monochrome or polychrome. The nature of the color can be varied and the article can present Jacquard or mottled designs.

The invention is further defined in the appended claims.

Claims (9)

  1. Method for manufacturing footwear, in particular socks, intended to exhibit hypoallergenic properties, characterized in that 5 yarns with low coefficient of friction of the carded or combed type are used, and spun from fibers hydrophilic of natural or semi synthetic origin, in that the footwear is produced by a non-compressive construction at the ribbing, uppers and soles, and in that the threads or the footwear are dyed by one or more non-sensitizing dyes on contact or after penetration into the skin, then said article is dried and formed.   2. Method according to claim 1, in which the yarns with a low coefficient of friction are chosen from cellulose fibers, cotton, silk, wool, linen and hemp. 3. Method according to claim 1 and claim 2, in which the non-compressive construction of the footwear is carried out while maintaining a length of absorbed yarn (LFA) sufficient to obtain extensions greater than 40%.   4. Method according to one of the preceding claims, in which the LFA is sufficient to obtain extensions greater than 50%.   5. Method according to one of the preceding claims, in which the LFA is sufficient to obtain extensions greater than 60%. 6. Method according to one of the preceding claims, in which the hydrophilic fibers of natural origin are chosen from cotton, linen, hemp, silk, wool and mixtures thereof.   7. Method according to one of the preceding claims, in which the hydrophilic fibers of semi-synthetic origin are viscose and rayon.   8. Method according to one of the preceding claims, in which the elastic thread or filament, such as elastane, possibly present in the article, is covered by a thread of hydrophilic material, in order to constitute its soul and therefore avoid contact with the skin.   9. Method according to one of the preceding claims, wherein the threads or the footwear are dyed with one or more dyes devoid of irritant and sensitizing power. 10. Method according to one of the preceding claims in which the non-irritant and non-allergenic dye is chosen from the group formed: - Cibacron LSR yellow - Cibacron HR yellow - Cibacron LS4G 1 yellow 5 - Cibacron LS3R blue scarlet Cibacron LS2G - Cibacron LSB red - Cibacron HD red Cibacron HF red - Navy Cibacron H2G 1. Method according to claim 1, characterized by the addition of a dye post-treatment intended to remove any non-residual dye chemically linked to the fiber, which consists in adding rinsing phases to the finished product, the number of which depends on the color and the dye recipe adopted, or else on exhaustion by solvent vapors.   12. The method of claim 1, characterized in that it further comprises a procedure for validating the hypoallergenic effect of the finished product, by tests for evaluating the irritant and sensitizing power and in particular by the method of Marzulli Maibach .   13. Footwear, in particular socks, obtained according to the defined process   according to one of claims 1 to 12.