EP1433897A1 - Process of making hosiery and articles thus manufactured - 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

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

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

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

The manufacture of a sock is based on knitting yarns, one forming the surface the outer side of the sock, the other the plating thread, forming the inner surface of the sock. These wires, identical or different in nature, have physicochemical properties not inert to the skin. The induced irritations can be of order chemical or physical, even pathological.

The physical irritations result in part from the surface condition of the wire as well as 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 whose effect abrasive can be demonstrated by tests on synthetic skin.

The physical irritations of the skin also come from the thermal properties of the fiber. Due to their chemical nature, in particular their hydrophilic-lipidic nature, certain fibers promote an increase in foot temperature and as a result the moistness of the skin. This phenomenon is at the origin of perspiration, development of bacteria, even the appearance of fungi. Each of these events contributes to irritate the skin.

Chemical irritations result from the presence of sensitizing molecules on the surface of the fiber. Chemical molecules, brought in by dyeing or by various processes wire or footwear, come into contact with the skin. Under the action of sweat, they can penetrate the epidermis and reach the dermis. Some originally inert molecules, such as azo molecules, then turned out sensitizers due to the breakdown of some of their chemical bonds. This contact or the penetration of coloring molecules, explains certain aggressions of the skin, including clinical symptom may be eczema, itching, redness.

• à réduire les irritations provoquées par le caractère abrasif de certains fils, en optant pour des fils à faible coefficient de friction,
• à réduire les irritations provoquées par une construction trop comprimante de la chaussette, en maintenant une LFA adéquate autorisant une extension, d'au moins 40 %, de préférence d'au moins 50 % et mieux encore de plus de 60% de la largeur de la chaussette au niveau du bord-côte, de la tige et de la semelle,
• à réduire les phénomènes de transpiration excessive grâce à l'utilisation de fibres suffisamment hydrophiles, au titre desquelles le coton, le lin et notamment des fibres naturelles,
• à réduire les risques de formations de dermatite de contact en utilisant des colorants non sensibilisants dont la propriété est déterminée à l'aide de leur formule par étude du caractère toxicologique de chacun des groupements chimiques constituant la molécule. Cette étude est complétée par un test de validation, suivant la méthode de Marzulli Maibach, évaluant le pouvoir irritant et sensibilisant du colorant à l'état pur,
• à supprimer les risques de formation de dermatites de contact provoquées par la présence de colorants résiduels non liés chimiquement à la fibre, en augmentant le nombre de rinçages du produit fini après teinture. Le nombre de rinçages est fonction du coloris et de la recette de teinture. Il est évident que pour une teinture foncée avec un épuisement plus faible, il sera nécessaire d'avoir recours à 2 ou 3 rinçages supplémentaires. Pour une teinture plus claire le nombre de rinçages sera plus faible.

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

• to reduce the irritations caused by the abrasive nature of certain threads, by choosing threads with a low coefficient of friction,
• to reduce the irritations caused by an overly compressive construction of the sock, by maintaining an adequate LFA allowing an extension, of at least 40%, preferably of at least 50% and better still of 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 whose 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, following the method of Marzulli Maibach, evaluating the irritant and sensitizing power of the dye in the pure state,
• to eliminate the risks of the formation of contact dermatitis caused by the presence of residual dyes not chemically linked to the fiber, by 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 reduce skin contact with synthetic threads or filaments, such as those from petrochemicals, using a wire whose elastic core, generally made of elastane, is wrapped with a thread with hydrophilic properties (such as cotton, linen and viscose) according to one of the existing processes in the textile industry while, on the contrary, prohibiting polyamides traditionally used because of their hydrophobic properties.

The hypoallergenic nature of the finished product is then verified by tests allowing to assess the irritant and sensitizing power of the product, such as the Marzulli method and Maibach (KLIGMAN A.M. The identification of contact allergens by human assay J. of Investigative Dermatol. 1996, 47, 393-409 - KLIGMAN A.M., EPSTEIN W. Updating the maximization test for identifying contact allergens, Contact Dermatites 1975, 1, 231-239 - MARZULLI F.N., MAIBACH H.I. 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., MAIBACH H.I. Contact allergy: predictive test in man. Dermatitis Contact 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 of patch tests. Ann.Dermatol. Venerol 1983, 110, 509-268.

The construction of the sock is done by knitting on a circular loom. We can also design the knitting of the sock flat by sewing or any other garment operation.

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

The method according to the invention is defined by the following methods, preferred or necessary to make socks that do not have allergenic properties: using for knitting a low friction yarn, preferably carded or combed and making a construction making it possible to obtain sock extensions equal to or greater than 50% at 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 cellulosic fiber such as cotton. The soul can be made up 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 yarn or footwear, have a chemical formula which is not not likely to cause sensitization phenomena on skin contact or after penetration into the skin.

• le jaune Cibacron LSR,
• le jaune Cibacron HR,
• le jaune Cibacron LG4S,
• le bleu Cibacron LS3R,
• l'écarlate Cibacron LS2G,
• le rouge Cibacron LSB
• le rouge Cibacron HD,
• le rouge Cibacron HF,
• le marine Cibacron H2G.

The dyes used lacking irritant and / or allergenic properties are preferably dyes of the Cibacron type and in particular the following dyes:

• Cibacron LSR yellow,
• the yellow Cibacron HR,
• the yellow Cibacron LG4S,
• Cibacron LS3R blue,
• scarlet Cibacron LS2G,
• Cibacron LSB red
• Cibacron HD red,
• Cibacron HF red,
• the marine Cibacron H2G.

Other dyes belonging to neighboring chemical classes may also be suitable such as, for example, natural colorants such as alizarin or indicagotine. We can also use direct acting dyes in the presence of activators or dye rise retarders.

The article of footwear can be knitted either from dyed yarn or from unbleached yarn followed by a diving dye. We will prefer this second option in order to get rid of the finished product, during the dyeing process, various size products deposited on the yarn in order to facilitate its passage on knitting loom.

The dyeing of the thread or footwear is done by soaking after adding different adjuvants necessary for its mounting on the fiber.

One or more additional rinses are then carried out, possibly after addition. soap. In the case of light colors, the number of additional rinses will be lower. A single rinse will generally suffice. Anyway the number of rinses will be depending on the chemical nature of the dye and its dye behavior. Socks are then dried, for example in a tumbler type rotary drum with or without circulation air.

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 non-allergenic character tests such as the Marzulli-Maibach test. For this purpose, we take a sample of sock which we grind to obtain a patch. This patch is applied to the skin, especially of healthy human volunteers.

Tests have shown the complete absence of allergy phenomena on a large batch and significant of healthy volunteers.

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

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

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

The invention is defined more precisely in the appended claims.

Claims (13)

Method for manufacturing footwear, in particular socks, intended to exhibit hypoallergenic properties, characterized in that yarns of low coefficient of friction of the carded or combed type are used, and spun from hydrophilic fibers 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 the article is dried and formed. The method of claim 1, wherein the low coefficient of friction wires are chosen from cellulosic fibers, cotton, silk, wool, linen and hemp. The method of claim 1 and claim 2, wherein the non-constructing compression of the footwear is carried out by maintaining a length of thread absorbed (LFA) sufficient to obtain extensions greater than 40%. Method according to one of the preceding claims, in which the LFA is sufficient to obtain extensions greater than 50%. Method according to one of the preceding claims, in which the LFA is sufficient to obtain extensions greater than 60%. 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 of these. Method according to one of the preceding claims, in which the hydrophilic fibers of semi-synthetic origin are viscose and rayon. Method according to one of the preceding claims, in which the wire or filament elastic, like elastane, possibly present in the article, is covered by a yarn of hydrophilic material, in order to constitute its soul and thus avoid contact with the skin. Method according to one of the preceding claims, in which the threads or the article footwear are dyed with one or more dyes devoid of irritant power and sensitizer. Method according to one of the preceding claims, in which the non-irritant and non-sensitizing dye is a Cibacron chosen from the group formed by: Cibacron LSR yellow yellow Cibacron HR Cibacron LS4G yellow Cibacron LS3R blue scarlet Cibacron LS2G Cibacron LSB red red Cibacron HD Cibacron HF red the marine Cibacron H2G Process according to Claim 1, characterized by the addition of a dye post-treatment intended to remove any residual dye not chemically bonded to the fiber, which consists in carrying out rinsing phases of the finished product, the number of which depends on the color and the dye recipe adopted or on exhaustion by solvent vapors. Method for manufacturing footwear according to claim 1, characterized in that it also 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. Footwear, including socks, obtained by the defined process according to one of claims 1 to 12.