JP2005533198A - Cut and wear resistant fiber structure - Google Patents

Abstract

The present invention is a fibrous structure comprising at least one non-composite para-aramid strand and at least one nylon strand maintained in a parallel relationship with each other, wherein the non-composite para-aramid strand is structured. Relates to structures present in the material in an amount ranging from about 20% to 99.9% by weight, based on the weight of the body. The invention also relates to a method of manufacturing such a structure and to a high cut and wear resistant protective garment manufactured from this structure, such as gloves, aprons and sleeves.

Description

  The present invention relates to a highly abrasion resistant fiber structure comprising a special structure of non-composite p-aramid strands and nylon strands. This structure can be used to produce protective garments having high cut resistance and high wear resistance.

  Aramids and more specifically para-aramids are a relatively new class of materials that find use in the areas of mechanical protection and thermal protection. High cut protection performance can be obtained from a woven or knitted assembly made from para-aramid fibers. Para-aramid fibers are therefore often used in the production of protective clothing for industrial workers, firefighters, sportsmen, military officials and police officers.

  One disadvantage of para-aramid fibers is that they tend to suffer from relatively low wear resistance due to their fibrillation tendency. The risk associated with this poor wear resistance is that the cutting performance of the protective garment decreases with wear time. In this area of wear and friction protection, and therefore low wear, nylon is superior, but they do not provide sufficient cutting performance.

  There remains a need to provide materials that have both high durable cutting performance and very high wear resistance.

  There are a number of factors that affect the wear resistance of a fabric. Abrasion performance may be tailored by selection of fiber component type, fiber properties, woven / knitted structure, fabric mass per unit area, number of fibers per unit volume, or relaxation tolerance of the fiber components in the fiber bundle. Often, the addition of wear resistant materials in a given structure containing a cut resistant component generally provides higher wear performance at the expense of cut resistance.

  (Patent Document 1) discloses a reinforcing component that is a composite yarn manufactured from a nylon twisted yarn spirally wrapped with another nylon twisted yarn and is knitted in a mating relationship with a main body yarn. Yes. The manufacture of such yarns is complicated and requires several steps. Furthermore, the reinforcing fabric thus obtained is still unsatisfactory with respect to cut resistance.

  It has now been found that by combining special fiber components in a special structural style, it is possible to realize very high cut and wear resistant fibrous materials quickly, directly and easily . In particular, it is possible to reach the same cut resistance level with a higher level of wear resistance than if the same fiber components were either incorporated separately or combined in different structural styles.

US Pat. No. 5,319,950

  One aspect of the present invention is a fibrous structure comprising at least one non-composite para-aramid strand and at least one nylon strand maintained in a parallel relationship with each other, the non-composite para-aramid strand. A structure in which the strands are present in the structure in an amount ranging from about 20% to about 99.9% by weight, based on the weight of the structure.

  Another aspect of the present invention is a method for producing the above structure comprising the step of processing non-composite para-aramid strands and nylon strands in a parallel relationship with each other.

Another aspect of the present invention is:
a) providing a strand of at least one non-composite para-aramid strand and at least one nylon strand;
b) feeding the strands into the knitting or loom without prior assembly;
c) high cut resistance comprising knitting or weaving the fibrous structure without changing the order in which the strands maintained in parallel with each other during the entire knitting or weaving process are fed into the machine And a method for providing a fiber structure having wear resistance.

  A further aspect of the invention is a high cut and wear resistant protective garment, in particular a glove, apron or sleeve made from the above fiber structure.

  The fiber structure of the present invention has high wear resistance. It also has a very high cut resistance. By using the structure of the present invention, it is possible to manufacture a protective garment having high cutting resistance and wear resistance such as work gloves. Gloves made from the fibrous structure of the present invention are comfortable to wear and by wearing them, the user does not lose the natural dexterity of their hands.

  The fiber structure of the present invention also finds use in the ballistic region, which has a very good penetration resistance.

  Furthermore, since the para-aramid strands of the present invention are non-composite, the method of manufacturing the fiber structure is very simple and straightforward and does not require any pretreatment or placement of the strands. The manufacturing method can therefore be completed with a minimum number of steps, allowing a quick, easy and cost-effective realization of any fiber structure.

  “Fibrous structure” as used herein includes a two- or three-dimensional structure comprising a fibrous material. Preferably, the structure includes a knitted fabric, a woven fabric, a unidirectional fabric, a nonwoven fabric, and / or combinations thereof. “Combination” means any assembly means such as a structure, of different nature and / or structure, sewn, glued, stitched, etc., either in the same plane or not, eg as a multi-layer structure Means that they may be assembled together. “Nonwoven fabric” means a fibrous material combined into a bonding matrix of polyethylene, polypropylene, polyamide, phenols, epoxy resin, polyester or mixtures thereof.

  “Fibrous material” as used herein includes infinite fibers such as filaments, short fiber structures, short cut fibers, microfibers, multifilaments, cords, yarns, fibers, pulps. The fibers may be made into staple fiber yarns spun into staple fibers, into infinite fiber yarns, or into stretch-break yarns that can be described as intermediate yarns between staple and continuous yarns. .

  “Strand” as used herein means an ordered assembly of fibrous material having a high length to diameter ratio, preferably at least 1000 times its diameter. The strand may be round, flat, or have another cross-sectional shape, or it may be a hollow fiber. By “non-composite strand” is meant a single simple strand as opposed to an assembled strand such as a co-twisted strand, a co-textured strand, a blended strand, a core-spun strand, and combinations thereof.

  The structure of the present invention comprises at least one non-composite para-aramid strand.

Aramids are polymers that are predominantly or exclusively of aromatic rings that are linked by carbamide bridges or, optionally, and also by other bridging structures. The structure of such aramid is represented by the repeating unit of the following general formula (—NH—A 1 —NH—CO—A 2 —CO) n
Wherein A1 and A2 are the same or different and may also represent optionally substituted aromatic and / or polyaromatic and / or heteroaromatic rings. Typically A1 and A2 are one or more which may comprise halogen, C1-C4 alkyl, phenyl, carboalkoxyl, C1-C4 alkoxyl, acyloxy, nitro, dialkylamino, thioalkyl, carboxyl and sulfonyl 1,4-phenylene, 1,3-phenylene, 1,2-phenylene, 4,4′-biphenylene, 2,6-naphthylene, 1,5, which may or may not be substituted -May be independently selected from naphthylene, 1,4-naphthylene, phenoxyphenyl-4,4'-diylene, phenoxyphenyl-3,4'-diylene, 2,5-pyridylene and 2,6-quinolylene. . The —CONH— group may also be replaced by a carbonyl-hydrazide (—CONHNH—) group, an azo- or an azoxy group.

  These aramids are generally prepared by polymerization of diacid chlorides or the corresponding diacids and diamines.

  Examples of aramids are poly-m-phenylene-isophthalamide and poly-p-phenylene-terephthalamide.

Additional suitable aromatic polyamides are of the following structure:
(-NH-Ar1-X-Ar2-NH-CO-Ar1-X-Ar2-CO-) n
In the formula, X represents O, S, SO2, NR, N2, CR2, CO.

  R represents H, C1-C4 alkyl, which may be the same or different, Ar1 and Ar2 may have at least one hydrogen atom substituted with halogen and / or C1-C4 alkyl 1,2- Selected from phenylene, 1,3-phenylene and 1,4-phenylene.

  Further useful polyamides are disclosed in U.S. Pat. No. 4,670,343, in which aramid is a copolyamide in which at least 80 mole percent of all A1 and A2 are preferably present. 1,4-phenylene and phenoxyphenyl-3,4'-diylene which may be substituted or unsubstituted, and the content of phenoxyphenyl-3,4'-diylene is 10 mol% to 40 Mol%.

  Additives may be used with aramids, in fact, up to as much as 10% by weight of other polymeric materials may be blended with aramid, or aramid diamines may be replaced with as much as 10% of other diamines. Alternatively, it has been found that copolymers in which aramid diacid chloride is substituted with as much as 10% other diacid chloride may be used.

  The non-composite para-aramid strands of the present invention preferably have an elongation of 5% or less, measured according to American Society for Testing and Materials (ASTM) D885-98. Preferably, the para-aramid strands have a modulus of about 10 to about 2500 g / denier, preferably about 1000 to about 2500 g / denier, and a tenacity of about 3 to about 50 g / denier, preferably about 3 to about 38 g / denier. Have Elastic modulus and tenacity are measured according to the ASTM D885-98 method.

  The structure of the present invention may comprise several para-aramid strands. In such a case, these strands are independent of each other. Para-aramid strands are structures of the present invention in an amount ranging from about 20% to about 99.9%, preferably from about 30% to about 70% by weight, based on the total weight of the structure. Present in.

  The strands are extracted from the anisotropic spinning stock solution using well-known void spinning methods, such as those described in US Pat. Nos. 3,767,756 or 4,340,559. Generally spun.

  The structure of the present invention also comprises at least one nylon strand. “Nylon” means a strand made from an aliphatic polyamide polymer. Suitable nylons in the present invention include polyhexamethylene adipamide (nylon 66), polycaprolactam (nylon 6), polybutyrolactam (nylon 4), poly (9-aminononanoic acid) (nylon 9), polyenanthate Lactam (nylon 7), polycapryl lactam (nylon 8) and polyhexamethylene sebacamide (nylon 6,10) are included. A preferred nylon is polyhexamethylene adipamide (nylon 66).

  In a preferred embodiment of the present invention, the nylon strand is a textured strand. By “textured strand” is meant a strand that has been subjected to a treatment, such as air jetting, to mix together the originally parallel filaments that make up the strand.

  Preferred nylon strands of the present invention have an elongation of 18% or less and a tenacity of 10 gpd or less. Elongation and tenacity are measured according to ASTM D885-98.

  Nylon strands are generally spun by extrusion of a polymer melt through a capillary tube into a gas coagulation medium. Such methods are well known.

  Suitable nylon strands of the present invention include the trade name “Cordura” by EI du Pont de Nemours and Company, Delaware, Delaware. Registered product) ”is included.

  The structure of the present invention may comprise several nylon strands.

  Non-composite para-aramid strands and nylon strands are maintained in a parallel relationship with each other in the structure of the present invention. “Parallel”, as used herein, has an angle of approximately zero between one strand along its entire continuous length and any other strand along its entire continuous length. Means that. All the strands remain independent and are separated from each other. They are not intimately blended, they are not co-twisted, they are not mixed, not mixed, not interlaced, not mixed, and textured Not even been. One does not wrap any other and they do not form a core spun fiber or a sheath core.

  In a preferred embodiment of the fiber structure of the present invention, the non-composite para-aramid strands are present in an amount ranging from about 30% to about 70% by weight, and the nylon strands are based on the weight of the structure. It is present in an amount ranging from about 30% to about 70% by weight.

  In addition to the non-composite para-aramid strands and nylon strands described above, the structures of the present invention may comprise additional artificial or natural strands. These additional strands include polyethylene strands, polyester strands, acrylic strands, acetate strands, meta-aramid strands, glass strands, steel strands, ceramic strands, polytetrafluoroethylene strands, cellulose strands Included are strands, cotton strands, silk strands, wool strands and mixtures thereof. These additional strands are based on the total weight of the structure, as long as their presence in the structure of the present invention does not negatively affect the special high wear and cut resistance of the structure of the present invention. And may be present in an amount ranging from about 0.25% to about 25% by weight. These additional strands are also maintained in a parallel relationship with any other strands present in the structure.

  The structure of the present invention exhibits very good cut resistance. In a preferred embodiment of the present invention, the structure of the present invention has a combined normalized index CTPCPI. Of 80 g / mm or greater, more preferably 90 g / mm or greater, measured as described below. N is shown. The structure of the present invention also exhibits very good wear resistance. In a preferred embodiment of the invention, the structure exhibits a wear resistance of 1000 cycles or more, more preferably 3000 cycles or more, measured according to the EN 388 method. In a more preferred embodiment of the invention, the structure has a combined standardization index CTPCPI.80 of 80 or more, measured as described below. Both wear resistance over 1000 cycles, measured according to N and EN 388, are shown.

The structure of the present invention preferably has a medium weight, measured according to the EN 388 method, in the range of about 200 g / m ² to about 1500 g / m ² , preferably in the range of about 300 g / m ² to about 800 g / m ^2. Show.

  The structure of the present invention can be produced by any classic woven or knitted production method that allows parallel placement of the strands that make up the structure (knitting, weaving, laying down in one direction, combining strands with a binding matrix to form a nonwoven fabric. Manufactured). For example, in a knitting or weaving method, the strands are fed directly to the knitting or weaving machine without any kind of pre-assembly. For example, in the knitting method, the order in which the strands are fed into the knitting needles of the knitting machine remains the same throughout the entire knitting process. A preferred method for producing the structure of the present invention is a knitting method.

  The structure of the present invention may be used in the manufacture of gloves, aprons, sleeves and any protective garment that requires high cut and wear resistance.

  The invention will be described in greater detail with reference to the following examples.

Test Methods and Examples Description Abrasion Resistance In the following examples, the abrasion resistance of the samples is measured according to the Standard European Method EN 388 (July 1994), “Protective Gloves against”. Measured according to subsection 6 “Abrasion resistance” of the section entitled “Mechanical Risks”.

  The device is designed to provide a controlled amount of wear between the fabric surface and the selected abrasive with a relatively low contact pressure of (9 +/− 0.2) kPa in a continuously changing direction. And a Martindale wear and abrasion tester. Circular samples were polished with standard abrasive glass paper (brand F2 grit 100 quality 117).

  Wear continued and the samples were examined at suitable intervals without removing them from their holders. The fraying situation was characterized by yarn breakage and the average value of the cycle to reach this break was recorded and averaged over 6 samples.

  The test is performed at (23 +/− 2) ° C. and (50 +/− 5)% relative humidity.

  The greater the number of cycles required to reach failure, the higher the wear resistance of the sample.

Cut resistance In the following examples, cut resistance is “Standard test method for measuring cut resistance of materials used in protective closing”, Measured according to ASTM standard F1790-97.

  In conducting the test, the cutting edge under specified force was drawn once across the sample mounted on the cylindrical mandrel. The distance drawn from the initial contact to the cutout was recorded at several different forces, and a graph was drawn of the force as a function of the distance to the cutout. From the graph, the forces (in grams) for clipping at distances of 25.4 and 10 millimeters were determined and standardized to justify the consistency of the blade. These standardized forces are hereinafter referred to as NL1 (for 25.4 mm distance) and NL2 (for 10 mm distance), respectively. The blades are 70 mm sharp blade stainless steel cutter blades with a load of 4 N on neoprene sheets of approximately (1.57 +/− 10%) mm and (50 +/− 5) Shore A hardness. Was calibrated by using This was done at the start and end of the test. A new blade was used for each measurement, ie each load. The sample was a rectangular piece of 50 × 100 millimeter woven or knitted fabric placed at a 45 degree bias. The mandrel was a round conductive bar with a radius of 38 millimeters on which the sample was attached using double-sided tape. The cutting edge was drawn across the knitted fabric on the mandrel perpendicular to the longitudinal axis of the mandrel. The cutout was recorded when the cutting edge was in electrical contact with the mandrel. Standardized forces were reported as NL1 and NL2 in grams for cut resistance, cut lengths of 25.4 mm and 10 mm, respectively.

  The test is performed at (23 +/− 2) ° C. and (50 +/− 5)% relative humidity.

  A 25.4 mm cut can be classified as a tear-like cut and a 10 mm cut can be classified as a penetration-like cut. These two belong to different regions of cutting-length (cutting-force relationship which is a non-linear curve). It was therefore convenient to define a combination index that has the advantage of mixing the two behaviors. This index is hereinafter referred to as the Combined Tear Puncture Cut Performance Index (CTPCPI). It was computed by the following equation:

  This index was further standardized for a constant weight of the fabric construction and was selected below at 800 grams per square meter. This mass per square area is a realistic value for protective clothing applications such as gloves for industrial use.

  This combined standardized index is given in grams per millimeter of cut length. The higher this index, the higher the cut resistance of the sample.

  For each example, 12 samples were tested. The result is an average of the results of 12 tests.

Component Non-Composite Para-Aramid Strand A: Commercially available from EI DuPont de Nemours and Company under the trade name Kevlar® staple aramid fiber, Type 970 A staple para-aramid yarn having a linear density of 714 dtex and an equivalent Nm = 28/2 (in dtex = 10000 / Nm). Synthetic fiber staples were produced from short 38-mm long para-aramid fibers by the state-of-the-art spinning method used to produce para-aramid staple yarns. Para-aramid short fibers were obtained by cutting continuous filament para-aramid yarns made of 1000 filaments of 1.5 dpf (1.6 dtex) each.

  Nylon Strand B: Commercially available by EI DuPont de Nemours & Company under the trade name Cordura® type 200, linear density 370 dtex, equivalent Nm = 55/2 (decitex = Nylon 66 staple yarn (at 10,000 / Nm). Synthetic fiber staples were made from short 38 mm long aliphatic polyamide nylon 66 fibers by the state of the art spinning method used to make aliphatic polyamide staple yarns. Aliphatic polyamide short fibers were obtained by cutting continuous filament yarns each made of 1.9 dtex filaments.

  Examples 1 and 2 are comparative examples. Example 3 is an example according to the present invention. Because the results are comparative, all three examples achieved a relatively constant value of total decitex (representing the linear density of the fiber) and a relatively constant value of mass per surface area.

Example 1 (comparison)
5 independent non-composite para-aramid strands A supplied to circular knitting machine (Fiber Analysis Knitter from Lawson-Hamfill) without any kind of pre-assembly did. A sufficiently long sleeve was knitted to obtain a uniform reproducible pattern of mass per surface area close to 800 g / m ² .

  Samples were cut to the appropriate size and shape (circular for wear tests, rectangular for cutting performance measurements) to perform 6 wear and 12 cut tests.

  Each sample therefore had a total decitex of 3570 (5 times 714 decitex).

  The measured wear resistance was 900 cycles.

  The force measured in the cut resistance test was 821 g for a cut length of 25.4 mm and 1666 g for a cut distance of 10 mm. Combination CTPCPI. The N normalization index was given by the following calculation [(821 / 25.4 + 1666/10) / 2] × 800/800 and was equal to 99 g / mm.

Example 2 (comparison)
Ten independent nylon strands B were fed to the same circular knitting machine used in Example 1 without any kind of pre-assembly. A sufficiently long sleeve was knitted to obtain a uniform reproducible pattern of mass per surface area close to 826 g / m ² .

  Samples were cut to the appropriate size and shape (circular for wear tests, rectangular for cutting performance measurements) to perform 6 wear and 12 cut tests.

  Each sample therefore had a total decitex of 3700 (10 times 370 dtex).

  The measured wear resistance was 3000 cycles.

  The force measured in the cut resistance test was 759 g for a cut length of 25.4 mm and 923 g for a cut distance of 10 mm. Combination CTPCPI. The N normalization index was given by the following calculation [(759 / 25.4 + 923/10) / 2] × 800/826 and was equal to 59 g / mm.

  CTPCPI. N shows a cutting resistance which is inferior to 40% in comparison with Example 1. On the other hand, the abrasion resistance of Example 2 is three times better than that of Example 1.

Example 3 (Invention)
Three independent non-composite para-aramid strands A and four independent nylon strands B were fed into the same circular knitting machine as used in Example 1 without any kind of pre-assembly. A sufficiently long sleeve was knitted to obtain a uniform reproducible pattern of mass per surface area close to 843 g / m ² .

  Samples were cut to the appropriate size and shape (circular for wear tests, rectangular for cutting performance measurements) to perform 6 wear and 12 cut tests.

  Each sample therefore had a total decitex of 3622 (3 times 714 dtex + 4 times 370 dtex). Each sample comprised 50.1 wt% uncomplexed para-aramid strands, based on the weight of the sample, and 40.1 wt% nylon strands, based on the weight of the sample.

  The measured wear resistance was 6000 cycles.

  The force measured in the cut resistance test was 1170 g for a cut length of 25.4 mm and 1400 g for a cut distance of 10 mm. Combination CTPCPI. The N normalization index was given by the following calculation [(1170 / 25.4 + 1400/10) / 2] × 800/843 and was equal to 88 g / mm.

  CTPCPI. N shows substantially the same cutting resistance as that of Example 1. On the other hand, the abrasion resistance of Example 3 is 6 times better than that of Example 1, and surprisingly it is 2 times better than that of Example 2.

  The following table summarizes the results obtained in Examples 1-3.

Claims (12)

  A fibrous structure comprising at least one non-composite para-aramid strand and at least one nylon strand maintained in a parallel relationship with each other, wherein the non-composite para-aramid strand comprises A structure present in the structure in an amount ranging from about 20% to 99.9% by weight, based on weight.   Based on the weight of the structure, the non-composite para-aramid strands are present in an amount ranging from about 30 wt% to about 70 wt%, and the nylon strands are from about 30 wt% to about 70 wt%. The structure of claim 1 present in an amount in the range of weight percent.   The structure of claim 1, wherein the nylon strand is a textured strand.   2. The method for producing a fiber structure according to claim 1, comprising a step of processing the non-composite para-aramid strand and the nylon strand in a parallel relationship with each other.   The method of claim 4, wherein the processing comprises knitting, weaving, laying down or combining the strands with a bonding matrix to form a nonwoven fabric.   The method according to claim 5, wherein the processing is knitting.   A high cut-resistant and wear-resistant protective garment manufactured from the fiber structure according to claim 1.   A high cut-resistant and wear-resistant glove manufactured from the fiber structure according to claim 1.   A highly cut and wear resistant sleeve made from the fibrous structure of claim 1.   A high cutting and wear resistant apron produced from the fibrous structure of claim 1. a) providing a strand of at least one non-composite para-aramid strand and at least one nylon strand;
b) feeding the strands into a knitting or loom without prior assembly;
c) knitting or weaving a fibrous structure without changing the order in which the strands maintained in parallel with each other throughout the entire process of knitting or weaving are fed into the machine; A method for providing a fiber structure having cutability and wear resistance. Combination standardization index CTPCPI. 2. The structure of claim 1 exhibiting an abrasion resistance of 1000 cycles or more measured according to N and EN 388.