EP1881095A1 - Thread for the production of a cutting and abrasion resistant textile surface - Google Patents

Abstract

The yarn for making up a cut-resistant and abrasion-resistant textile surface using spun high-tenacity polyamide staple fibers. The tenacity of polyamide staple fibers is greater than 4.5 cN/dtex and a length of the fibers is 40-65 mm. The fibers are converted by cracking, cutting, carding, drawing or cottonizing. A modulus of the yarn is greater than 10 GPa, and a total yarn count is 2.5-50 Nm. A proportion of high-tenacity polyamide is 15-85% of a total weight of the entire yarn, and a fineness of the high-tenacity polyamide fibers is 0.5-8 dtex. The yarn for making up a cut-resistant and abrasion-resistant textile surface using spun high-tenacity polyamide staple fibers. The tenacity of polyamide staple fibers is greater than 4.5 cN/dtex and a length of the fibers is 40-65 mm. The fibers are converted by cracking, cutting, carding, drawing or cottonizing. A modulus of the yarn is greater than 10 GPa, and a total yarn count is 2.5-50 Nm. A proportion of high-tenacity polyamide is 15-85% of a total weight of the entire yarn, and a fineness of the high-tenacity polyamide fibers is 0.5-8 dtex. A proportion of textured polyamide is 5-30% of the total weight of the entire yarn. The yarn is produced in a form of a primary yarn, where a twist coefficient of the primary yarn is 30-90, and a twist yarn, where a twist coefficient of the twist yarn is 25-85. An independent claim is included for a textile surface.

Description

The invention relates to a yarn for the manufacture of a textile surface resistant to cutting and abrasion.

Documents are known US 3,883,898 , GB 1,586,890 , US 4,777,789 , US 4,004,295 , GB 2,018,323 , DE 1,610,495 and EP 0 118 898 that the use of fibrous polymers of different kinds, reinforced or not with fibers or inorganic filaments, glass or metal for example, provides good resistance to cutting.

It should be noted that the cut resistance is governed in Europe by the EN 388 standard which defines 5 levels of performance, called classes, ranging from 1 to 5 and increasing with the level of performance.

In products not reinforced with organic fibers, the choice of materials is rather limited. The materials generally used are polyphenylene terephthalamide (PPTA), liquid crystal polymer (LCP), or high molecular weight polyethylene, that is to say having a molecular weight greater than 600,000 g / mol. The fibers thus formed can be used alone or combined with polyamide fibers.

All these polymers, called technical polymers, have in common high modules and very high mechanical strengths. However, the modules are rarely greater than 100 GPa, with tensile strengths greater than 2,000 MPa.

These very strong modulus values for organic fibers, however, are much lower than those corresponding to inorganic fibers of carbon, silicon carbide (SIC) or super alloys type.

High modules are synonymous in general stiffness, and often penalize the ability of gripping operators, inducing some discomfort. In this case, operators may not wear protective devices, which are in most cases used as gloves.

These gloves are, for the vast majority of applications, knitted on special machines that make it possible to obtain gloves without requiring retouching.

Three types of machines, defined according to their gauge, that is to say the number of needles per inch, are generally used.

A first type of machine, defined by a gauge 7, makes heavy gloves, protective but unwieldy. A second and a third types, respectively defined by a gauge 10 and a gauge 13, make it possible to produce medium gloves and fine gloves respectively.

Medium gloves are the most used, especially in the automotive industry, mechanics, electrical engineering, the glass industry, packaging or handling. These industries generally use gloves manufactured in gauge 10 and meeting the requirements of class 3, defined by standard EN 388.

In addition to the disadvantages described above, concerning the rigidity of the technical polymers, these products are of a very high price. In some industries, this often forces decision-makers to stay on inappropriate solutions, such as cotton or leather gloves, and thus expose operators to both discomfort and the risk of injury.

In addition, in the field of end-of-life recycling of products, there is the problem of cost as well as damage to the environment.

Two solutions exist, which are landfill disposal or incineration. In the latter case, some polymers generate dangerous products, such as hydrogen cyanide (HCN), as well as other undesirable compounds.

The object of the present invention is therefore to overcome these disadvantages by proposing a thread intended for the manufacture of a textile surface resistant to cutting and abrasion, to meet the requirements of class 3 of EN 388 , while improving the comfort for the user as well as the recyclability of the products made, and reducing the manufacturing costs thereof.

To this end, the invention relates to a yarn intended for the manufacture of a textile surface resistant to cutting and abrasion, characterized in that it is obtained by spinning high tenacity polyamide fiber yarns, the toughness is greater than 4.5 cN / dTex and the fiber length is between 40 and 170 mm.

According to a first embodiment, the fibers are converted by cracking, by cutting, by carding or by drawing and have a length of between 65 and 140 mm.

According to a second embodiment, the fibers are processed by cotton and have a length of between 40 and 65 mm.

Preferably, the yarn comprises polyvinyl alcohol fibers HPF type ("High Performance Fiber"), whose module is greater than 10 GPa.

This type of fiber makes it possible to improve the performance of the yarn in the face of the cut.

According to one characteristic of the invention, the thread comprises textured polyamide 6.6 fibers.

This type of fiber improves the behavior of the yarn against abrasion.

Advantageously, the proportion of high-tenacity polyamide is between 15 and 85% of the total weight of the entire yarn.

Preferably, the proportion of textured polyamide is between 5 and 30% of the total weight of the entire yarn.

According to one characteristic of the invention, the fineness of the high tenacity polyamide fibers is between 0.5 and 8 dTex.

According to a possibility of the invention, the fineness of the Polyamide HPF fibers is between 0.5 and 8 dTex.

Advantageously, the total yarn count is between Nm 2.5 and Nm 50.

According to an alternative, the wire is made in the form of a primary wire, the torsion coefficient of the primary wire being between 30 and 90.

According to another possibility, the wire is made in the form of a twisted wire, the twist coefficient of the twisted wire being between 25 and 85.

The invention also relates to a textile surface formed from yarns according to the invention.

In any case, the invention will be better understood from the description which follows, with reference to the appended schematic drawing.

Figure 1 is a diagram showing the evolution of the cleavage index with respect to the fiber composition of the yarn.

• le polyamide haute ténacité, noté également Pa HT,
• l'alcool polyvinylique de type HPF (« High Performance Fiber »), noté également PVA HPF.

Ces deux polymères sont des matériaux thermoplastiques, semi cristallins. Plus particulièrement, le polyamide haute ténacité utilisé peut être du type de celui destiné au renforcement des pneumatiques et des tuyaux sous pressions, qui n'est habituellement pas utilisé à des fins textiles mais qui possède de bonne propriétés de résistance à la coupure.In order to produce the yarn according to the invention, two families of polymers are used, both recyclable, namely:

• the high tenacity polyamide, also noted Pa HT,
• polyvinyl alcohol HPF type ("High Performance Fiber"), also noted PVA HPF.

These two polymers are thermoplastic, semi-crystalline materials. More particularly, the high tenacity polyamide used may be of the type intended for reinforcing tires and pressurized pipes, which is not usually used for textile purposes but has good cut resistance properties.

The yarn comprises high tenacity polyamide fibers of polypropylene type 6,6, the toughness of which is greater than 4.5 cN / dTex and whose unitary titer is between 2.5 and 7 dTex. The fibers are obtained by a slow and progressive cracking process, given their high strength, between 6 and 12 cN / dTex. However, they have a significant elongation of rupture giving the product a module less than 10 GPa. This low module allows the realization of knitted gloves that are comfortable for the user.

The yarn furthermore comprises polyvinyl alcohol fibers of the HPF type, the modulus of which is greater than 10 GPa. This type of fiber is usually used to strengthen the cement.

These fibers were also chosen according to their high mechanical strength, of the order of 11 cN / dTex, for a significant elongation of rupture, of the order of 8%, conferring on the fibers a modulus of the order of 20 GPa. The latter have a fineness of between 2 and 5 dTex, and were made by a slow and progressive cracking process, given the high resistance thereof.

The high tenacity polyamide fibers and the polyvinyl alcohol fibers of the HPF type have average lengths that are compatible with the spinning process, namely between 40 and 170 mm, preferably between 80 and 110 mm.

The yarn is preferably formed by spinning from Pa HT fiber yarns and PVA HT fiber yarns. It could also, according to an alternative, be made solely from Pa HT fiber yarns.

It is also possible to add to Pa HT fibers and PVA HPF, a filament of textured polyamide 6,6 fibers may represent for example between 15 and 25% of the total mass of the yarn. Such an addition makes it possible to increase the properties of resistance to abrasion.

The wire used is preferably of the Nm 28/2 type, that is to say a twisted yarn in two strands, for which 28 km of yarn can be obtained from a kg of material.

The wire is composed of a primary wire and a secondary wire. The torsion coefficient is defined for each of the wires. That is deduced from the following formula: $$\begin{array}{ll}\mathrm{T}\mathrm{=}\mathrm{\alpha }\mathrm{(}\mathrm{nm}{\mathrm{)}}^{\mathrm{1}\mathrm{/}\mathrm{2}}& \mathrm{with\; T}\mathrm{=}\mathrm{twist\; in\; turns}\mathrm{/}\mathrm{m}\mathrm{,}\\ & \mathrm{\alpha }\mathrm{=}\mathrm{torsion\; coefficient}\mathrm{,}\mathrm{dimensionless}\mathrm{,}\\ & \mathrm{=}\mathrm{metric\; number\; in\; m}\mathrm{/}\mathrm{boy\; Wut}\end{array}$$

The torsion coefficient α on the primary thread Nm 25/1 (35.7 Tex) is between 30 and 90. The torsion coefficient on the twisted yarn is between 25 and 85. It should be noted that the torsion coefficient exerts an influence on the comfort and resistance to abrasion. This parameter has little effect on cut resistance.

The best compromise is obtained for a torsion coefficient of the order of 60 on the primary wire, and of the order of 55 on the twisted wire. In the case where a textured polyamide filament is added, the torsion coefficient thereof is substantially equal to that of the twisted yarn.

In order to check whether this thread makes it possible to produce textile surfaces in accordance with the EN 388 standard with regard to the requirements relating to the protection against cutting, gloves have been produced by knitting on a knitting machine of Gauge 10. These gloves were then tested according to the criteria of EN 388.

The table below shows the results of the tests, carried out in the technical center. This summarizes, depending on the type of wire used, the index and the class reached with regard to the requirements relating respectively to cutting and abrasion.

We will focus more particularly on the cutoff index, which is proportional to the number of passages that the test slide loaded with a certain weight, defined by the standard, must perform. Thus, the higher the cut index is inside a class, the more the product is resistant to the cut. In order for the product to fulfill the requirements of class 3, the cut resistance must be between 5 and 10 with regard to cut resistance.

• un fil de type Nm 28/2, composé exclusivement de fibres de Pa HT,
• un fil de type Nm 28/2, composé exclusivement de fibres de PVA HPF,
• un fil de type Nm 28/2, comportant 50% en masse de fibres de Pa HT et 50 % en masse de fibres de PVA HPF.
• un fil de type Nm 28/2, comportant 41 % en masse de fibres de Pa HT, 41 % en masse de fibres de PVA HPF et 18 % en masse de filament de Polyamide 6,6 texturé.

Type de fil Coupure Abrasion Nm 28/2 Indice 5,9 500<Indice<2000 100 % Pa HT Classe 3 Classe 3 Nm 28/2 Indice 4,6 100<Indice<500 100 % PVA HPF Classe 2 Classe 3 Nm 28/2 Indice 7,5 500<Indice<2000 50 % Pa HT Classe 3 Classe 3 50 % PVA HPF Nm 28/2 Indice 8,5 Indice>8000 41 % Pa HT Classe 3 Classe 4 41 % PVA HPF 18 % filament Pa 6,6 texturé On remarque que tous les types de fil, hormis celui composé exclusivement de fibres de PVA HPF, remplissent les exigences de la classe 3 en ce qui concerne la protection face à la coupure.Four types of yarn were tested, namely:

• a Nm 28/2 type wire, composed exclusively of Pa HT fibers,
• a Nm 28/2 type wire, composed exclusively of HPF PVA fibers,
• a Nm 28/2 type wire, comprising 50% by weight of Pa HT fibers and 50% by mass of PVA HPF fibers.
• a Nm 28/2 type wire, comprising 41% by weight of Pa HT fibers, 41% by weight of PVA HPF fibers and 18% by weight of textured Polyamide 6.6 filament.

Type of wire cut Abrasion Nm 28/2 Index 5.9 500 <Index <2000 100% Pa HT Class 3 Class 3 Nm 28/2 Index 4.6 100 <Index <500 100% HPF PVA Class 2 Class 3 Nm 28/2 Index 7,5 500 <Index <2000 50% Pa HT Class 3 Class 3 50% HPF PVA Nm 28/2 Index 8.5 Index> 8000 41% Pa HT Class 3 Class 4 41% HPF PVA 18% filament Pa 6.6 textured It is noted that all types of yarn, except the one composed exclusively of HPF PVA fibers, meet the requirements of Class 3 with regard to protection against cutting.

In addition, by comparing the last two types of yarn, it is noted that the addition of a textured polyamide 6,6 filament can improve the properties of the product, particularly in the face of abrasion.

Figure 1 shows the evolution of the cleavage index as a function of the composition of the wire in Pa HT and PVA HPF.

It is noted that the highest cutoff index is obtained for a composition of the yarn of 50% by weight of Pa HT fibers and 50% by weight of PVA HPF fibers. In addition, as can also be seen from the table above, a wire composed exclusively of Pa HT fibers makes it possible to fulfill the requirements of class 3.

It goes without saying that the invention is not limited to the composition of this thread, described above as examples, but it embraces all variants. This is how the thread could be made from high tenacity polyamide alone or high tenacity polyamide combined with textured polyamide 6,6 fibers, without HPF type polyvinyl alcohol fibers, without departing from the scope of the invention.

Claims (13)

Yarn for making a cut-resistant and abrasion-resistant textile surface, characterized in that it is obtained by spinning high-tenacity polyamide fiber yarns, the toughness of which is greater than 4.5 cN / dTex and whose fiber length is between 40 and 170 mm. Yarn according to claim 1, characterized in that the fibers are converted by cracking, cutting, carding or drawing and have a length of between 65 and 140 mm. Yarn according to claim 1, characterized in that the fibers are processed by cotton and have a length of between 40 and 65 mm. Yarn according to one of claims 1 to 3, characterized in that it comprises polyvinyl alcohol fibers HPF type ("High Performance Fiber"), whose module is greater than 10 GPa. Yarn according to one of claims 1 to 4, characterized in that it comprises textured polyamide 6.6 fibers. Yarn according to one of claims 1 to 5, characterized in that the proportion of high-tenacity polyamide is between 15 and 85% of the total weight of the whole yarn. Yarn according to one of claims 5 and 6, characterized in that the proportion of textured polyamide is between 5 and 30% of the total weight of the entire yarn. Yarn according to one of Claims 1 to 7, characterized in that the fineness of the high-tenacity polyamide fibers is between 0.5 and 8 dTex. Yarn according to one of Claims 4 to 8, characterized in that the fineness of the Polyamide HPF fibers is between 0.5 and 8 dTex, their toughness being greater than 4.5 cN / Tex. Yarn according to one of Claims 1 to 9, characterized in that the total yarn count is between Nm 2.5 and Nm 50. Thread according to one of claims 1 to 10, characterized in that it is in the form of a primary thread, the torsion coefficient of the primary wire being between 30 and 90. Yarn according to one of claims 1 to 10, characterized in that it is in the form of a twisted yarn, the twist coefficient of the twisted yarn being between 25 and 85. Textile surface formed from yarns according to one of claims 1 to 12.

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