Method for manufacturing a cut resistant fabric and a cut resistant fabric

Abstract

A method for manufacturing a cut resistant fabric includes: supplying a polyethene yarn with a thickness of 50-225 dtex as a protective yarn through a first yarn carrier of a circular knitting machine to a feeder needle at a first selected tension; supplying simultaneously an uncoated elastane yarn with a thickness of 20-80 dtex as a first additional yarn through a second yarn carrier of the circular knitting machine to the same feeder needle at a second selected tension that is higher than the first selected tension of the protective yarn; forming a fabric from the protective yarn and the first additional yarn as single-jersey knits; and interlocking the protective yarn and the first additional yarn in each single-jersey knit of the fabric using a heat treatment step on a stenter frame.

Claims

1. A method for manufacturing a cut resistant fabric, comprising the steps of: supplying a polyethene yarn with a thickness of 50-225 dtex as a protective yarn through a first yarn carrier of a circular knitting machine to a feeder needle at a first selected tension; supplying simultaneously an uncoated elastane yarn with a thickness of 20-80 dtex as a first additional yarn through a second yarn carrier of the circular knitting machine to the same feeder needle at a second selected tension, wherein the second selected tension of the first additional yarn is higher than the first selected tension of the protective yarn and a length of the first additional yarn supplied to one machine cycle of the circular knitting machine is between 5% and 25% of a length of the one machine cycle of the circular knitting machine, forming the cut resistant fabric as a tubular structure from the protective yarn and the first additional yarn as single-jersey knits using the circular knitting machine; cutting the tubular structure in half to form a fabric plane; setting the fabric plane on a stenter frame maintaining the length of the first additional yarn in the fabric; interlocking the protective yarn and the first additional yarn in each single-jersey knit of the cut resistant fabric using a heat treatment step on the stenter frame to stabilize the cut resistant fabric.

2. The method according to claim 1, including using a polyethene yarn with a thickness of 100-120 dtex as the protective yarn and using an uncoated elastane yarn with a thickness of 30-78 dtex is used as the first additional yarn.

3. The method according to claim 1, wherein a temperature of the heat treatment step is between 100° C. to 150° C.

4. The method according to claim 1, including supplying a second additional yarn to every second first feeder instead of the protective yarn.

5. The method according to claim 1, wherein the second selected tension is such that length of the first additional yarn supplied to one machine cycle of the circular knitting machine is between 10% and 15% of a length of the one machine cycle of the circular knitting machine.

6. The method according to claim 1, including washing the fabric before the heat treatment.

7. The method according to claim 6, including using an anti-crease agent as a lubricant in washing.

8. A cut resistant fabric, comprising: protective yarns for providing cut resistance to the fabric, the protective yarns being a polyethene yarn with a thickness of 50-225 dtex; and first additional yarns for binding protective yarns together in the fabric, the first additional yarn comprising an uncoated elastane yarn with a thickness of 20-78 dtex; wherein individual stitches are formed from the protective yarns and first additional yarns, each stitch having the protective yarn and the first additional yarn extending parallel to each other and being interlocked with each other, the stitches forming a single-jersey knit of the fabric, the fabric having a plurality of single-jersey knits, wherein the first additional yarns, when interlocked with the parallel extending protective yarns, have a residual tension in the fabric resulting from the first additional yarns having been stretched, prior to being interlocked, to a length of 110% to 150% of a length of the first additional yarn in an unstretched state of the first additional yarn, a length of the fabric in a maximum stretch state of the fabric is 135%-165% of length of the fabric in an unstretched state and a length of the fabric in a use state is stretched by 10%-25% of a length of the fabric in the unstretched state.

9. The fabric according to claim 8, wherein the protective yarn is a polyethene yarn with a thickness of 100-120 dtex.

10. The fabric according to claim 8, wherein the first additional yarn is an uncoated elastane yarn with a thickness of 30-50 dtex.

11. The fabric according to claim 8, wherein the residual tension is such that the first additional yarns are stretched to length of 120% to 130% of the length of the additional yarn in unstretched state.

12. The fabric according to claim 8, wherein abrasion resistance, cut resistance and tear resistance of the fabric each have a value of 2-5 according to the EN388 standard.

13. The fabric according to claim 8, wherein a second tension of the first additional yarn in the fabric is such that the first additional yarn is stretched to a length of 160%-250% relative to an unstretched first additional yarn of a corresponding length.

14. The fabric according to claim 8, wherein the fabric comprises only single-jersey knits that are identical to each other.

15. The fabric according to claim 8, wherein a basis weight of the fabric ranges between 180 and 220 g/m2.

16. The fabric according to claim 8, wherein the protective yarn and first additional yarn of each single-jersey knit of the fabric are interlocked by a heat treatment.

17. The fabric according to claim 16, wherein a length of the fabric after the heat treatment is 92-96% of a length of the fabric before heat treatment, shrinkage of fabric being 4-8%.

18. The fabric according to claim 8, wherein the fabric has 25 to 30 stitches per inch.

19. The fabric according to claim 8, wherein the first additional yarn is 100% elastane.

20. The fabric according to claim 8, wherein the fabric meets requirements of the EN388 standard regarding cut resistance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described below in detail by making reference to the appended drawings that illustrate some of the embodiments of the invention, in which:

(2) FIG. 1a shows block diagrams illustrating an apparatus that is suitable for implementing the method according to the invention,

(3) FIG. 1b is an axonometric basic view of a circular knitting machine that can be used in the method according to the invention,

(4) FIG. 1c is an axonometric basic view of another circular knitting machine that can be used in the method according to the invention,

(5) FIG. 2 shows block diagrams illustrating the steps of the method according to the invention,

(6) FIG. 3a illustrates a garment formed from a fabric according to the invention worn by a user,

(7) FIG. 3b illustrates a garment formed from a fabric according to the invention separately,

(8) FIG. 4a is an enlarged view of a prior art single-jersey knit,

(9) FIG. 4b is an enlarged view of detail A of the enlargement of the fabric of FIG. 3,

(10) FIG. 4c is a rear view of the enlargement of FIG. 4a,

(11) FIG. 4d is an enlarged view of a fabric according to another embodiment,

(12) FIG. 5 illustrates the supply of protective yarn and first additional yarn separately to the same feeder of a circular knitting machine.

DETAILED DESCRIPTION OF THE INVENTION

(13) The method according to the invention can be implemented with the apparatus according to FIG. 1a including a circular knitting machine 100 and preferably processing equipment 102. For example, the circular knitting machine 100 can be a prior art circular knitting machine similar to that illustrated in FIGS. 1a and 1b, into which yarns are supplied from bobbins 104. According to prior art, a circular knitting machine forms knits 18 according to FIGS. 4b-4d, which in this case are single-jersey knits, from yarns using needles 111 shown in FIG. 5. For example, the circular knitting machine can be a circular knitting machine made by German Terrot GmbH or Mayer&Cie GmbH&Co, having 20-32, preferably 24-28 needles per inch. The diameter of the circular knitting machine can range between 1000 and 2000 mm, for example.

(14) More precisely, prior art circular knitting machines 100 illustrated in FIGS. 1b and 1c include a multi-angle frame 110 fitted against a base, a needle cylinder 112 containing needles arranged on top of the frame 110 and further, a creel arrangement 114 for feed devices arranged on top of the needle cylinder 112. In addition, the circular knitting machine 100 includes several yarn feed devices 116 forming individual feeders 103 according to FIG. 5, suspended in supporting rings 118 and 120 included in the creel arrangement 114 for supplying the yarn 104. The yarn feed devices 116 are driven by at least one motor 122 via power transmission means 124. In this context, when speaking of guiding of yarns to a feeder of the circular knitting machine, guiding of yarns to the same needle using separate yarn carriers is meant.

(15) As shown in FIG. 2, the fabric according to the invention is manufactured with the method for manufacturing a cut resistant fabric, wherein, in step 200, polyethene yarn with a thickness of 50-130 dtex, preferably 100-120 dtex, is supplied to the circular knitting machine as protective yarn and, in step 202, elastane yarn with a thickness of 20-80 dtex, preferably 30-50 dtex, is supplied to the circular knitting machine as first additional yarn in such a way that the first additional yarn is supplied parallel with each protective yarn through the same feeder of the circular knitting machine to the needles, both at their own tension. The fabric is formed from the protective yarn and the first additional yarn supplied as a single-jersey knit in step 204. In this context, double-feeding more precisely means that first additional yarn is also always supplied to the needles parallel with the protective yarn through each feeder of the circular knitting machine. In the method, a part can also be replaced, preferably every other protective yarn, with second additional yarn having more affordable investment costs. For example, the second additional yarn can be polyester yarn, which has notably lower investment costs compared to the price of corresponding polyethene yarn. Correspondingly, other additional yarns can also be used, but the minimum amount of protective yarn is in any case at least 40% and at most 95% by weight of the total weight of the fabric.

(16) The tension applied in supplying the first additional yarn is between 5% and 25%, preferably between 10% and 15% for each machine cycle relative to the length of the machine cycle. In other words, the first additional yarn is supplied under tension, whereat the first additional yarn is stretched. When the first additional yarn runs through the circular knitting machine together with the protective yarn, the tension force acting on the first additional yarn of the yarn feed devices of the circular knitting machine can be partly released, whereat the first additional yarn can partly recover towards its unstretched dimension. Thus, in a fabric according to the invention, the first additional yarn tightens the protective yarn forming a dense and cut resistant fabric. The first additional yarn has a residual tension in the fabric when the first additional yarn is stretched by 10% to 50%, preferably by 20% to 30%, in the final fabric after the heat treatment.

(17) Advantageously, when using Dyneema yarn, for instance, as the cover yarn, the supply length of protective yarn for a machine cycle of 2.8 m is 7.63 m, whereas, for a Lycra yarn used as the first additional yarn, the supply length is 5.55 m. Thus, the tension of both yarns may be 4 cN-6 cN, preferably 4.5 cN-5.5 cN. According to FIG. 5, both the protective yarn 12 and the first additional yarn 14 are supplied each through its own yarn carrier 125 in the feeder 103; that is, for example, the protective yarn 12 through the opening 128 and the first additional yarn 14 through the feed wheel 130 and the slot 126 to the same needle 111. When supplied through separate yarn carriers 125, both the protective yarn 12 and the first additional yarn 14 have their own tensions, as the tighter yarn does not pull the looser yarn in the same yarn carrier. In other words, adjustment of yarn tensions can be performed notably accurately in the method.

(18) According to an embodiment the diameter of the circular knitting machine is 71 cm, and the length of the machine cycle is 224 cm. In this embodiment 800 cm of protective yarn is fed for each machine cycle and 280 cm of first additional yarn.

(19) The fabric produced with the circular knitting machine is in the form of a tube. Before any heat treatment of the fabric the tubular structure of the fabric is cut in half in step 206 of FIG. 2 to form a fabric plane. This enables the fabric to be set on a stenter frame as a fabric plane without stretching the fabric in step 207.

(20) Advantageously, the post-processing equipment 102 of FIG. 1a used for fabric finishing includes a washing machine 106 and a stenter frame 108. In the washing machine, the fabric manufactured with the circular knitting machine is washed in step 208 of FIG. 2 using chemicals for washing, which are manufactured, for example, by a Dutch company Tanatex Chemicals B.V. The purpose of washing is to remove impurities from the fabric and stabilise the fabric. The temperature used in washing may range, for example, between 40° C. and 80° C., preferably between 50° C. and 70° C. An anti-crease agent for synthetic materials, which is a lubricant, is advantageously used during washing. The purpose of the lubricant is to prevent fabric abrasion during washing.

(21) The purpose of the stenter frame is to heat up the fabric to a sufficiently high temperature in step 210, whereat the fabric shrinks and the fabric stabilises regarding its dimensions. The washing machine and the stenter frame can be prior art equipment. For example, the washing machine manufacturer can be SOL and the stenter frame manufacturer can be Brückner Trockentechnik GmbH & Co. KG. The temperature in the heat treatment step advantageously ranges between 100° C. and 150° C. In addition to the washing and heat treatment, finishing may also include other steps, such as a stretch treatment, with which it is attempted to influence end product properties.

(22) From a fabric according to the invention manufactured with a method according to the invention, it is possible to manufacture several different products, in which cut resistance is particularly relevant. FIG. 3a shows one such product put on a wearer 30 representing a cut resistant sleeve 22, which is useful, for example, in car mechanic jobs. Car mechanics must put their hands in many places lacking a direct sight, thus exposing their hands to incised wounds and burns.

(23) FIG. 4a shows an enlargement of a prior art fabric. According to the figure, the single-jersey knit has traditionally been poorly suited to cut resistant fabrics 10, since a very large open area 24 remains between the stitches 16. Thus, per unit area, the single-jersey knit 18 has a notably small amount of protective yarn 12, which provides cut resistance for the fabric 10. This defect can be compensated by increasing the thickness of protective yarn, but then the fabric becomes thick and its stretch and usability suffer.

(24) According to FIG. 3b, the situation is different in the fabric 10 according to the invention, since, thanks to its elasticity, the first additional yarn 14, or elastane yarn, simultaneously supplied with each protective yarn 12 pulls the stitches 16 in the fabric 10 notably close to each other, whereat the amount of protective yarn 12 per unit area remarkably increases and the open area 24 remains small. In turn, FIG. 4c is a rear view of the same fabric 10 according to the invention, wherein the stitches 16 look slightly different compared to the front view. It is essential that the protective yarn and the first additional yarn are not wrapped around each other before the supply to the needle so that both yarns can be supplied at a selected tension. In other words, the protective yarn and the first additional yarn run parallel to each other to each needle and through each knit of the fabric, as shown in FIGS. 4b-4d.

(25) Polyethene yarn used as the protective yarn in the method and fabric according to the invention may be polyethene yarn known under the tradename Dyneema with a thickness of 50-225 dtex, preferably 100-120 dtex. In turn, as the first additional yarn, elastane yarn known under the tradename Lycra can be used, its thickness ranging from 20 to 80 dtex, preferably from 30 to 50 dtex. The first additional yarn is advantageously 100% elastane yarn to ensure that the first additional yarn can be supplied sufficiently stretched at the right tension. The thickness of the second additional yarn partially replacing the polyethene yarn can also be between 50 and 130 dtex, preferably between 100 and 120 dtex. FIG. 4d illustrates a second embodiment of the fabric according to the invention, wherein second additional yarn 20 has been supplied to every other needle to partly replace protective yarn 12. In association with second additional yarn 20, first additional yarn is also supplied as a double-feed parallel to the second additional yarn 20. When using replacing second additional yarn in every other needle, almost the same level of cut resistance is achieved; however, tear resistance of the fabric notably reduces in this case. Elastane yarn used in a fabric according to the invention must have such properties that it enables the supply to the circular knitting machine at the above-mentioned tension and, in addition, recovers from the stretched state to its original length without permanent deformation.

(26) With a cut resistant fabric according to the invention, the following resistance values are achieved in tests according to the EN388 standard, when the fabric only included polyethene yarn as protective yarn and elastane yarn as first additional yarn. Regarding abrasion, the value of the resistance level is 3 on a scale of 1-4, the tear resistance value is 4 on a scale of 1-4, and the cut resistance value is 2 on a scale of 1-5. When part of polyethene yarn is replaced with second additional yarn, the tear resistance value drops from 4 to 2. If necessary, cut resistance or tear resistance can be increased by using a fabric according to the invention folded over, since the thin structure of the fabric yarn according to the invention enables the manufacture of a stretchy garment even with the fabric folded over. Products requiring greater cut resistance may be, for example, neck protections and similar.

(27) It is surprising that the fabric according to the invention achieves quite high, even excellent values in tests according to the EN388 standard for tear resistance, for example, since the thicknesses of protective yarns and first additional yarns used are less than half of what has been generally used in prior art applications requiring cut resistance. However, a double-feed of the first elastic additional yarn generates forces that pull protective yarns towards each other forming a dense net of protective yarns.

(28) From the fabric according to the invention, it is possible to manufacture garments for several different applications. Applications of the fabric according to the invention can include garments related to occupational safety and health for public and security services, garments for pet care, working clothes and sports clothes. A high degree of elasticity, thin structure and cut resistance of the fabric according to the invention enable the use of the fabric in protective underwear, for example. Particularly advantageous applications include cut resistant equipment for athletes, such as socks for ice hockey players and figure skaters and other wrist and ankle protections, serving the purpose of preventing cuts produced by skate blades during games.

(29) A fabric manufactured with a circular knitting machine comes from the circular knitting machine as a finished tubular structure, which is cut half into a plane form depending on the application. In the fabric, all knits advantageously have an identical structure, which facilitates the manufacture of the fabric.