Elasticised yarn, a method for making said yarn and elasticised fabric made therefrom

Abstract

An elastic thread yarn comprising linen and/or rami and/or hemp and an elastic thread, with a thread made of an elastomeric material, and a substantially inextensible yarn made of linen and/or rami and/or hemp helically wound about the elastomeric core at a predetermined number of windings per length unit of elasticized yarn, wherein, for each metric count Nm, the number of windings substantially inextensible yarn of the elasticized yarn, is set between two values indicated by two curves (12, 13) which can be expressed according to exponential laws, for example, with the same exponent, i.e. according to equations of the form T=K N.sup.0, 327 where K is 20 and 50, respectively. In particular, an intermediate curve 11 is such that, by choosing for a given metric count a number of windings proximate to curve 11, this best feature balance is obtained. In an exemplary embodiment, the core comprises a bare elastic thread, i.e. an elastic thread that is not coated by other fibers. In another exemplary embodiment, the core comprises an elastic thread coated with a natural fiber as cotton or viscose, or with a combination thereof. The elastic thread yarn according to the invention provides elasticized fabrics containing linen and/or on rami, which has, in particular, a better surface regularity than well-known elasticized fabrics comprising linen, and which is comparable with the regularity of the elasticized fabrics comprising natural fibers such as cotton, wool, etc. and synthetic fibers, and also allows using ramie and hemp yarns to make elastic thread yarns and fabrics, for example, for making cloth items.

Claims

1. An elastic thread yarn comprising: an elastic thread, comprising a thread made of an elastomeric material; a substantially inextensible covering yarn that is helically wound about said elastic thread forming a predetermined number T of covering windings per length unit of said elastic thread yarn, wherein said substantially inextensible covering yarn comprises linen and/or ramie and/or hemp, said inextensible covering yarn having a predetermined metric count Nm, wherein said metric count Nm of said inextensible covering yarn is set between 8 Km/Kg and 80 Km/Kg (10000/810000/80 dtex); wherein said covering windings are arranged next to each other to entirely cover said elastic thread according to a number T of covering windings which is responsive to a predetermined function of the metric count T=T(Nm), and wherein said predetermined function of the metric count T=T(Nm) is given by the equation:
T=T(Nm)=K(1000 Nm).sup.[1] where K is a number set between 25.9 and 46.7, and is 0.327.

2. The yarn according to claim 1, wherein K is a number set between 30 and 42.

3. The yarn according to claim 1, wherein K is a number set between 35 and 40.

4. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a linen yarn that has a metric count Nm of 10 Km/Kg, and said number T of covering windings is set between 650 and 850 windings per meter of elastic thread yarn.

5. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a linen yarn that has a metric count Nm of 24 Km/Kg, and said number T of covering windings is set between 850 and 1250 windings per meter of elastic thread yarn.

6. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a linen yarn that has a metric count Nm of 26 Km/Kg, and said number T of covering windings is set between 900 and 1250 windings per meter of elastic thread yarn.

7. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a linen yarn that has a metric count Nm of 36 Km/Kg, and said number T of covering windings is set between 900 and 1350 windings per meter of elastic thread yarn.

8. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a linen yarn that has a metric count Nm of 39 Km/Kg, and said number T of covering windings is set between 900 and 1350 windings per meter of elastic thread yarn.

9. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a linen yarn that has a metric count Nm of 50 Km/Kg, and said number T of covering windings is set between 900 and 1600 windings per meter of elastic thread yarn, in particular said number T of covering windings is set between 1000 and 1500.

10. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a linen yarn that has a metric count Nm of 75 Km/Kg, and said number T of covering windings is set between 1100 and 1700 windings per meter of elastic thread yarn.

11. The elastic thread yarn according to claim 1, wherein the substantially inextensible covering yarn is a ramie yarn that has a metric count set between 8 and 60.

12. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a ramie yarn that has a metric count Nm of 10 Km/Kg, and said number T of covering windings is set 650 and 850 windings per meter of elastic thread yarn.

13. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a ramie yarn that has a metric count Nm of 24 Km/Kg, and said number T of covering windings is set between 850 and 1250 windings per meter of elastic thread yarn.

14. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a ramie yarn that has a metric count Nm of 36 Km/Kg, and said number T of covering windings is set between 900 and 1350 windings per meter of elastic thread yarn.

15. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a ramie yarn that has a metric count Nm of 48 Km/Kg, and said number T of covering windings is set between 1000 and 1500 windings per meter of elastic thread yarn.

16. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a ramie yarn that has a metric count Nm of 60 Km/Kg, and said number T of covering windings is set between 1000 and 1500 windings per meter of elastic thread yarn.

17. The elastic thread yarn according to claim 1, wherein the substantially inextensible covering yarn is a hemp yarn that has a metric count set between 8 and 40.

18. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a hemp yarn that has a metric count Nm of 10 Km/Kg, and said number T of covering windings is set between 650 and 850 windings per meter of elastic thread yarn.

19. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a hemp yarn that has a metric count Nm of 18 Km/Kg, and said number T of covering windings is set between 750 and 1150 windings per meter of elastic thread yarn.

20. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a hemp yarn that has a metric count Nm of 24 Km/Kg, and said number T of covering windings is set between 850 and 1250 windings per meter of elastic thread yarn.

21. The elastic thread yarn according to claim 1, wherein said substantially inextensible covering yarn is a hemp yarn that has a metric count Nm of 36 Km/Kg, and said number T of covering windings is set between 900 and 1350 windings per meter of elastic thread yarn.

22. The elastic thread yarn according to claim 1, wherein said thread of elastomeric material has a metric count set between 70 dtex and 250 dtex.

23. An elastic thread yarn according to claim 1, wherein: said elastic thread is a Lycra elastic thread that has a metric count of 44 dtex; said substantially inextensible covering yarn is a linen inextensible covering yarn; said metric count Nm of said linen inextensible covering yarn is 39 Km/Kg; said linen inextensible covering yarn is S-twisted in said windings; said number T of covering windings per length unit is 1100 twistings per meter; said elastic thread yarn is produced at a stretch ratio of 3.9.

24. An elastic thread yarn according to claim 1, wherein: said elastic thread is a Lycra elastic thread that has a metric count of 78 dtex; said substantially inextensible covering yarn is a linen inextensible covering yarn; said metric count Nm of said linen inextensible covering yarn is 26 Km/Kg; said linen inextensible covering yarn is S-twisted in said windings; said number T of covering windings per length unit is 1120 twistings per meter; said elastic thread yarn is produced on a hollow spindle twisting machine at a hollow spindle rotation speed of 12000 RPM; said elastic thread yarn is produced at a stretch ratio of 3.9.

25. The elastic thread yarn according to claim 1, wherein said thread of elastomeric material has a metric count set between 100 dtex and 200 dtex.

26. The elastic thread yarn according to claim 1, wherein said elastic thread is a bare elastic thread.

27. The elastic thread yarn according to claim 1, wherein said elastic thread is an elastic thread coated with a natural fibre.

28. A method for making an elastic thread yarn comprising the steps of: prearranging a first spool containing a substantially inextensible covering yarn comprising linen and/or ramie and/or hemp, wherein said substantially inextensible covering yarn has a metric count Nm set between 8 and 80 (10000/810000/80 dtex); prearranging a second spool containing a yarn comprising an elastic thread, wherein said elastic thread is made of an elastomeric material; co-axially mounting said first spool on a hollow spindle that is adapted to rotate about its own axis at a predetermined speed; pulling said elastic thread from said second spool through said hollow spindle at an unwinding speed; causing said elastic thread with said linen and/or ramie and/or hemp-containing yarn to pass through an orifice co-axial to said hollow spindle; said method comprising, furthermore, steps of pulling, through said orifice, said elastic thread yarn consisting of said substantially inextensible covering yarn wound about said elastic thread, and winding said elastic thread yarn at a predetermined winding speed about a third spool, wherein such method is carried out on a hollow spindle twisting machine, wherein the hollow spindle, the orifice and a guide means for forming said centrifugal helical path are provided by such hollow spindle twisting machine, wherein said winding speed, said unwinding speed of said elastic thread and said speed of said hollow spindle are selected in such a way to wind a number of covering windings of said substantially inextensible covering yarn per each linear meter of said elastic thread yarn which is obtained by the equation
T=K(1000 Nm).sup.[1] where K is a number set between 25.9 and 46.7 and a 0.327, and wherein said covering windings are arranged next to each other to entirely cover said elastic thread.

29. The method according to claim 28, wherein K is a number set between 30 and 42.

30. The method according to claim 28, wherein K is a number set between 35 and 40, in particular is a number about 37.3.

31. An elastic thread yarn according to claim 1, wherein: said elastic thread is a Lycra elastic thread that has a metric count of 156 dtex; said inextensible covering yarn is a linen inextensible covering yarn; said metric count Nm of said linen inextensible covering yarn is 39 Km/Kg; said linen inextensible covering yarn is S-twisted in said covering windings; said number T of covering windings per length unit is 1300 twistings per meter; said elastic thread yarn is produced at a stretch ratio of 3.9.

32. An elastic thread yarn according to claim 1, wherein: said elastic thread is a spandex elastic thread that has a metric count of 156 dtex; said inextensible covering yarn is a linen inextensible covering yarn; said metric count Nm of said linen inextensible covering yarn is 26 Km/Kg; said linen inextensible covering yarn is S-twisted in said covering windings; said number T of covering windings per length unit is 1100 twistings per meter; said elastic thread yarn is produced at a stretch ratio of 3.9.

33. The yarn according to claim 3, wherein K is 37.3.

34. The elastic thread yarn according to claim 27, wherein said natural fiber is at least one of a cotton and a viscose fiber.

Description

(1) FIG. 1 shows a Cartesian diagram where the abscissa relates to the metric count of elastic thread yarns and the ordinate relates to the number of windings, i.e. the number of torsions given to a substantially inextensible linen, or rami or hemp yarn, per linear meter of said elastic thread yarn.

(2) In the diagram, some points are identified by the symbols (or .box-tangle-solidup.), .circle-solid., (or .square-solid.) which correspond to elastic thread yarns according to the invention, characterized by a metric count value Nm and by a number T of windings given to the initial substantially inextensible yarn per each meter of yarn produced.

(3) In particular, for each metric count value, a couple of points are identified by the symbols (or .box-tangle-solidup.), (or .square-solid.), and lays on the same vertical line, to indicate, for a determined metric count Nm corresponding to such vertical line, a winding number range by which products are obtained which show an acceptable compromise between elastic properties and surface features, with particular reference to the so-called orange skin defect. On the same vertical line, an intermediate point is identified with the symbol (.circle-solid.) to indicate, for the same metric count value, a preferred value of the number of windings, i.e. of torsions.

(4) The points (or .box-tangle-solidup.), .circle-solid., (or .square-solid.) fit three approximation curves 12, 13, 14, respectively, wherein: curve 12 shows the number T of windings per meter which leads to a surface irregularity density of the fabrics made of this yarn which lays within the acceptability limits. In particular, such number of windings can be fitted by a curve 12 of equation:
T=25.9(1000 N).sup.0.327[2]; curve 13 shows the number T of windings per meter below which the yarn, and the fabric obtained from them, has elastic properties suitable for making an elasticized item, in particular a fabric that is adapted to make general-purpose garments. In particular, these numbers of windings can be fitted by a curve 13 described by the equation:
T=46.7(1000 N).sup.0.327[3]; curve 14 shows the number T of windings per meter which makes it possible to obtain an elastic thread yarn with the best balance between surface regularity and elasticity. In particular, these numbers of windings can be fitted by a curve 14 described by the equation:
T=37.3(1000 N).sup.0.327[4].
Therefore, if for any metric count Nm* a number T of windings is selected in an area 14 proximate to curve 11, this best property balance can be obtained for metric count Nm*.

(5) In particular, twist tests were made to obtain the elasticized product according to the invention, starting from linen, rami or hemp inextensible yarns, by a Hamel-type hollow spindle twisting machine. Some examples of yarns, and of fabrics according to the invention are described hereinafter.

(6) Examples of Elastic Thread Yarns Obtained from Linen Inextensible Yarns of Various Metric Counts, and of Fabrics Obtained Starting from Such Yarns

(7) On a hollow spindle twisting machine, elastic thread yarns were made starting from linen inextensible yarns. The elastic properties of these elastic thread yarns were determined with reference to UNI EN 15930:2010 standard.

(8) Tables 1 and 2 show the properties of the material used, the production working conditions and the elastic properties, with reference to some exemplary test linen yarns.

(9) In particular, the examples 1 and 2 of table 1 relate to elastic thread yarns obtained using thick elastic threads (156 dtex), whereas the examples 3, 4 and 5 of table 2 relate to elastic thread yarns obtained using thin elastic threads (44 and 78 dtex).

(10) TABLE-US-00001 TABLE 1 EXAMPLE 1 EXAMPLE 2 Core elastic thread Lycra, 156 dtex Lycra, 156 dtex Inextensible yarn metric 26 39 count, Nm Winding speed of produced m/minute m/minute yarn Unwinding speed of elastic m/minute m/minute thread Spindle rotation speed RPM RPM Stretch ratio 3.9 3.9 Number of twisting/meter 1100 S 1300 S Elastic recovery 94% 88.8% Permanent stretch 65% 127.2%

(11) TABLE-US-00002 TABLE 2 EXAMPLE 3 EXAMPLE 4 EXAMPLE 5 Core elastic thread Lycra, 44dtex Lycra, Lycra, 78 dtex 78dtex Inextensible yarn metric count, Nm 39 39 26 Winding speed of produced yarn m/minute m/minute 8 m/minute Unwinding speed of elastic thread m/minute m/minute 2-3 m/minute Spindle rotation speed RPM RPM 12000 RPM Stretch ratio 3.9 3.9 3.9 Number of twisting/meter 1100 S 1300 S 1120 S Elastic recovery 89.2% 89.2% Permanent stretch 117.8% 122.7%

(12) The number of windings has been determined by taking a sample of the predetermined length and by fixing this first sample between a first fixed clamp and a second rotatable clamp, in order to untwist the sample and to count the number of turns that must be applied to the sample to obtain a thread substantially parallel to a yarn, i.e. the thread that forms the core of the product and the substantially inextensible yarn that has been used. As described, this method complies with EN ISO 2061 standard.

(13) In all cases, five 300 mm specimens were used for assessing the elastic properties. The specimens were subjected to a 0.01 cN/tex initial load, and to a progressive elongation at a test speed of 50 mm/minute, which gave 50% specific elongation. In such conditions, 4 60 seconds load cycles were carried out. Making an exception to the above-mentioned standard, the elastic thread yarn was pre-treated in water at 90 C. for 15 minutes.

(14) The elastic thread yarn of the example 5 had the following properties:

(15) I) Steam-Treated Yarn

(16) average ultimate strength: 1026 cN; average ultimate elongation: 8.3%
II) Elastic Thread Yarn Free in Steamed Skein average ultimate strength: 1040 cN; average ultimate elongation: 19.3%

(17) The above-mentioned properties were obtained according to ISO 2062:2010 standard, method A, carrying out in the cases I) and II) twenty-five tests with a 25 cm yarn test length, at an initial tensile stretch load of 0.21 N and at displacement speed of 250 mm/min. A CRE-Hounsfield dynamometer was used, equipped with a type of uncoated terminal clamps.

(18) The results show that the above linen yarns have the properties of an elasticized yarn, and that they are well-suited for making elasticized fabrics.

(19) TABLE-US-00003 Metric count, Nm T, windings/meter 10 700 24, 36 1100 50, 75 1300.

(20) Fabrics were produced by arranging the above-described linen elastic thread yarns according to the weft direction. The elastic properties of these elastic thread yarns were determined with reference to UNI EN 14704-1:2005 standard.

(21) The features of the material used, the production working conditions and the elastic properties are given in table 3.

(22) TABLE-US-00004 TABLE 3 EXAMPLE 6 EXAMPLE 7 Covering yarn see Example 1 see Example 2 Under load fabric 47.6 49.5 elongation Force decay due to 37.5 29.0 time Force decay due to 80.1 49.3 exercising Relaxation time 1 minute 30 minutes 1 minute 30 minutes Fabric growth after 21.8% 15.6% 16.2% 10% relaxation Recovered 78.2% 84.4% 83.8% 90% elongation Elastic recovery 164.4% 177.4% 160.5% 172.4% Modulus at 30% of 5.87 5.87 5.8 5.8 elongation, N

(23) In both cases, for computing the elastic properties ten 200 mm strip specimens were used. The specimens were subjected to five elongation cycles at a 100 mm/minute test speed. In such conditions, a load of 30 N was applied to the specimens during a 30 minutes application period. By modulus it is meant the force recorded during the last load cycle, at a predetermined elongation. The measurement uncertainty at 95% probability is 20% of under-load elongation and 20% of the residual elongation.

(24) The results show that the fabrics obtained from linen yarns have properties suitable for making elasticized items, in particular general-purpose cloth items.

(25) Furthermore, the fabrics produced are substantially free from surface irregularities like the so-called orange skin effect.

(26) Even with the yarn of example 5, an elasticized fabric was obtained which shows elastic properties only according to the weft direction, example 10. Such fabric was subjected to traction tests, in the weft and in the warp direction, according to EN ISO 13934-1:2000 standard. For the characterization three specimens were used of simply washed fabric and five specimens of refined fabric, which was refined by heating it up to a determined temperature and by maintaining the fabric at that temperature, i.e. by thermally stabilizing the fabric. Even in this case, the 200 mm specimens were stabilized at a fixed test speed of 100 mm/minute, after applying an initial tensile stretch of 5 N, in the case of the simply washed fabric, and of 2 N in the case of the refined, thermally stabilized fabric. The results are shown in tables 4 and 5.

(27) TABLE-US-00005 TABLE 4 EXAMPLE 10: SIMPLY WASHED FABRIC Warp Weft Average ultimate strength, N 1200 670 Maximum elongation % 8.0 47.0

(28) TABLE-US-00006 TABLE 5 EXAMPLE 6: REFINED, THERMALLY STABILIZED FABRIC Warp Weft Average ultimate strength, N 740 440 Maximum elongation % 13.0 34.0
Examples of Elastic Thread Yarns Obtained from Rami Inextensible Yarns Based (Boehmeria nivea) of Various Metric Counts, and of Fabrics Obtained Starting from Such Yarns

(29) On a hollow spindle twisting machine, elastic thread yarns were made starting from inextensible rami yarns. The elastic properties of these elastic thread yarns were determined with reference to UNI EN 15930:2010 standard.

(30) Table 6 shows the properties of the material used, the production working conditions and the elastic properties with reference to some exemplary test rami yarns.

(31) TABLE-US-00007 TABLE 6 EXAMPLE 11 EXAMPLE 12 Core elastic thread Lycra, 156 dtex Lycra, 156 dtex Inextensible yarn metric 36 48 count, Nm Winding speed of produced m/minute m/minute yarn Unwinding speed of elastic m/minute m/minute thread Spindle rotation speed RPM RPM Stretch ratio 3.9 3.9 Number of twisting/meter 1100 S 1300 S Elastic recovery 96% 97.6% Permanent stretch 75% 85.7%

(32) In both cases, 5 300 mm specimens were used for assessing the elastic properties. The specimens were subjected to a 0.01 cN/tex initial load, and to a progressive elongation at a test speed of 50 mm/minute, which gave 50% specific elongation. In such conditions, 4 60 seconds load cycles were carried out. Making an exception to the above-mentioned standard, the elastic thread yarn was pre-treated in water at 90 C. for 15 minutes.

(33) The results show that the above rami yarns have the properties of an elasticized yarn, and that they are well-suited for making elasticized fabrics.

(34) With similar results other yarns were also produced starting from rami inextensible yarns of different metric counts:

(35) TABLE-US-00008 Metric count, Nm T, windings/meter 10 700 24 1100 60 1300.

(36) Fabrics were produced by arranging the above-described rami elastic thread yarns according to the weft direction. The elastic properties of these elastic thread yarns were determined with reference to UNI EN 14704-1:2005 standard.

(37) The features of the material used, the production working conditions and the elastic properties are given in table 7.

(38) TABLE-US-00009 TABLE 7 EXAMPLE 13 EXAMPLE 14 Covering yarn see Example 9 see Example 10 Under load fabric 51.8 49.5 elongation Force decay due to 29.6 29.0 time Force decay due to 49.6 49.3 exercising Relaxation time 1 minute 30 minutes 1 minute 30 minutes Fabric growth after 12.6% 10% 11.1% 9% relaxation Recovered 87.4% 90% 88.9% 91% elongation Elastic recovery 168.8% 173.8% 179.5% 183.8% Modulus at 30% of 6.46 6.46 7.18 7.18 elongation, N

(39) In both cases, for computing the elastic properties ten 200 mm strip specimens were used. The specimens were subjected to 5 elongation cycles at a 100 mm/minute test speed. In such conditions, a load of 30 N was applied to the specimens during a 30 minutes application period. By modulus it is meant the force recorded during the last load cycle, at a predetermined elongation. The measurement uncertainty at 95% probability is 20% of under-load elongation and 20% of the residual elongation.

(40) The results show that the fabrics obtained starting from rami yarns have properties suitable for making elasticized items, in particular general-purpose cloth items.

(41) Further elastic thread yarns were produced from 8 to 60 metric count rami yarns, typically from rami yarns of metric count selected among 10, 24, 36, 48 and 60, in such a way to produce a number of windings per meter of substantially inextensible yarn between 500 and 1600.

(42) Furthermore, also in this case, the fabrics produced are substantially free from surface irregularities like the so-called orange skin effect.

(43) Examples of Elastic Thread Yarns Obtained from Inextensible Hemp Yarns (Cannabis sativa) of Various Metric Counts, and of Fabrics Obtained Starting from Such Yarns

(44) On a hollow spindle twisting machine, elastic thread yarns were made starting from inextensible hemp yarns. The elastic properties of these elastic thread yarns were determined with reference to UNI EN 15930:2010 standard.

(45) Table 8 shows the properties of the material used, the production working conditions and the elastic properties with reference to some exemplary test hemp yarns.

(46) TABLE-US-00010 TABLE 8 EXAMPLE 15 EXAMPLE 16 Core elastic thread Lycra, 156 dtex Lycra, 156 dtex Inextensible yarn metric 24 36 count, Nm Winding speed of produced m/minute m/minute yarn Unwinding speed of elastic m/minute m/minute thread Spindle rotation speed RPM RPM Stretch ratio 3.9 3.9 Number of twisting/meter 1100 S 1100 S Elastic recovery 78% 88.8% Permanent stretch 196% 155%

(47) In both cases, 5 300 mm specimens were used for assessing the elastic properties. The specimens were subjected to a 0.01 cN/tex initial load, and to a progressive elongation at a test speed of 50 mm/minute, which gave 50% specific elongation. In such conditions, 4 60 seconds load cycles were carried out. Making an exception to the above-mentioned standard, the elastic thread yarn was pre-treated in water at 90 C. for 15 minutes.

(48) The results show that the above hemp yarns have the properties of an elasticized yarn, and that they are well-suited for making elasticized fabrics.

(49) With similar results other yarns were also produced starting from hemp inextensible yarns of different metric counts:

(50) TABLE-US-00011 Metric count, Nm T, windings/meter 10 700 18 900.

(51) Fabrics were produced by arranging the above-described hemp elastic thread yarns according to the weft direction. The elastic properties of these elastic thread yarns were determined with reference to UNI EN 14704-1:2005 standard.

(52) The features of the material used, the production working conditions and the elastic properties are given in table 9.

(53) TABLE-US-00012 TABLE 9 EXAMPLE 17 EXAMPLE 18 Covering yarn see Example 15 see Example 16 Under load fabric 50.4 54.6 elongation Force decay due to 33.4 32.7 time Force decay due to 72.6 50.6 exercising Relaxation time 1 minute 30 minutes 1 minute 30 minutes Fabric growth after 19.8% 15.5% 11.6% 7.9% relaxation Recovered 80.2% 84.5% 88.4% 92.1% elongation Elastic recovery 159.3% 167.8% 162.0% 168.8% Modulus at 30% of 4.7 4.7 5.14 5.14 elongation, N

(54) In both cases, for computing the elastic properties 10 200 mm strip specimens were used. The specimens were subjected to 5 elongation cycles at a 100 mm/minute test speed. In such conditions, a load of 30 N was applied to the specimens during a 30 minutes application period. By modulus it is meant the force recorded during the last load cycle, at a predetermined elongation. The measurement uncertainty at 95% probability is 20% of under-load elongation and 20% of the residual elongation.

(55) The results show that the fabrics obtained starting from hemp yarns have properties suitable for making elasticized items, in particular general-purpose cloth items.

(56) Further elastic thread yarns were produced from 8 to 40 metric count rami yarns, typically from rami yarns of metric count selected among 10, 18, 24 and 36, in such a way to produce a number of windings per meter of substantially inextensible yarn between 700 and 1400, and of metric count 36, with a number of windings per meter set between 500 and 1600.

(57) Furthermore, also in this case, the fabrics produced are substantially free from surface irregularities like the so-called orange skin effect.

(58) The foregoing description of embodiments and of examples of the invention, and of the way of using the apparatus, will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such embodiment without further research and without parting from the invention, and, then it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology the is employed herein is for the purpose of description and, therefore, not of limitation.