Soft grey cloth made of flax yarns and production method

Abstract

The present invention provides the soft flax grey cloth for close-to-skin wearing application, said the fabric having flax yarns produced on an untwist and re-twist device. The device has a front drafting roller with a rubber roller on the top, a low power thin mini-motor with ceramic components inside its internal rotor, a back drafting roller with a rubber roller on the top, a grooved drum and a spinning tube. Flax yarns produced through the method could be enhanced in several fields: tensile stress, yarn count, twists, softness and hairiness, thus be profit to soften flax cloth. 20 24 20 47 74 10 J ul 2 02 4 A B S T R A C T 2 0 2 4 2 0 4 7 7 4 1 0 J u l 2 0 2 4 f l a x c l o t h . A B S T R A C T 2 0 2 4 2 0 4 7 7 4 1 0 J u l 2 0 2 4 f l a x c l o t h . 1 / 2 Figure 1 Figure 2 1 / 3 Untwist and re-twist Weaving or knitting Raw flax yarns Treated flax yarns Flax grey cloth Figure 1 1 2 3 4 5 6 7 8 9 10 Figure 2 20 24 20 47 74 10 J ul 2 02 4 1 / 3 U n t w i s t a n d r e - t w i s t W e a v i n g o r k n i t t i n g 2 0 2 4 2 0 4 7 7 4 1 0 J u l 2 0 2 4 9 1 0 1 / 3 U n t w i s t a n d r e - t w i s t W e a v i n g o r k n i t t i n g 2 0 2 4 2 0 4 7 7 4 1 0 J u l 2 0 2 4 9 1 0

Description

The present invention relates to the soft flax grey cloth, which has been found to be particularly useful in improving the softness of clothing, and thus it is involved in the textile field of technologies and equipment. BACKGROUND OF THE INVENTION Compared with most conventional natural fiber, flax fabrics do have many advantages, such as higher tensile strength, good water and heat transfer properties, electrical insulation and chemical stability, et.al. However, the application of flax fabrics also hindered from several disadvantages, especially harsh and stiff handle due to the high stiffness of flax fibres and yarns. Several strategies have been applied at different stages of the flax fabric production, such as biological enzyme treatment, softening treatment and washing. These treatments resulted in increased energy consumption and water pollution. It is also worth to note that most of current strategies focused on flax fibres and fabrics, but not yarns. There are two main technologies for producing flax yarns, namely wet spinning and dry spinning. It has been found that wet spinning flax yarn performed better than those produced using the dry spinning technology for most properties. However, wet spinning normally consumes higher energy to take away additional water from flax yarns, while dry spinning shows higher production efficiency and relatively lower costs. To meet the requirement for different end-use, and to overcome the tensile strength during spinning and weaving or knitting, certain amount of twists must be applied to flax yarns. The higher yarn twists, the tighter fibres become. This also provides flax fabric with higher load and smoother surface, but increased rigidity. Compared to cotton fibres, flax fibres showed worse fibre cohesion with higher stiffness and smoother fibre surface. Hence, it is still a challenge to achieve soft flax yarns and thus soft flax fabric with low yarn twists during spinning. The untwist and re-twist technology treated yarns via untwisting, drafting and re-twisting at the same time. After above treatment, yarns would become thinner and have less twists than 2024204774   10 Jul 2024 original yarns. This technology might also be of great potential application in other yarns made of luxury fibres, e.g. cashmere. Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application. SUMMARY OF THE INVENTION The present invention provides a soft flax grey cloth for close-to-skin wearing application, trying to avoid from additional harmful and / or high-cost treatments. The present invention can be achieved as shown below: The soft flax grey cloth can be woven or knitted using soft flax yarns. The soft flax yarns can be rotor spun yarns or ring spun yarns, and dry spinning yarns or wet spinning yarns, and these yarns will be treated on an untwist and re-twist device. The untwist and re-twist device has a low power thin mini-motor with an upper ceramic component, a lower ceramic component and a self-fixed pin inside its internal rotor. The shape of inner hole of the internal rotor is a square, and four small holes are set on the four sides of the inner hole respectively to place the self-fixed pin. The upper ceramic component has a raised curved surface in the centre, two limit lumps on two sides and a small hole on the top to place the self-fixed pin. The curved surface can softly hold yarns and its smooth surface can let yarns go smoothly. The two limit lumps can keep yarns in a relatively steady position. The lower ceramic component has a concave curved surface compared to the upper one, and the two surfaces work together to hold yarns. The radian of the curved surfaces of the upper and lower ceramic components can be set according to properties of different materials and yarn counts, preferably from 2 to 3. 2024204774   10 Jul 2024 The space between the upper and lower ceramic components can be set according to yarn counts via changing the thickness of limit lumps, preferably from 0.5mm to 2mm. The present invention further provides the method of untwist and re-twist on above device as illustrated below: Raw flax yarns go through the back roller, the back rubber roller, the thin mini-motor, the front roller and the front rubber roller, finally to be collected by the spinning tube driven by the grooved drum. The rotation direction of the mini-motor is contrary to the direction of yarn twists, while the treated yarns and the raw yarns have the same twist direction. The rotation rate of the mini-motor is the product of the yarn linear speed and the count of fibre slipping twists. The slipping twist means the cycles when fibres slippage is observed within untwisting yarns. The draft multiple can normally be set between 1.1 and 1.5. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be now described, for illustrative, but not limitative purposes, according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein: Figure 1 shows a sketch of the production of the flax grey cloth. Figure 2 is a sketch of the untwist and re-twist equipment. Figure 3 is a view of ceramic components. Figure 4 is a more detailed view of the upper ceramic component. Figure 5 shows the principle of untwist and re-twist yarns. 2024204774   10 Jul 2024 Numbers in above figures are explained below: 1-raw flax yarn, 2-back roller, 3-back rubber roller, 4-ceramic components, 5-low power thin mini-motor, 6-front rubber roller, 7-front roller, 8-treated flax yarn, 9-grooved drum, 10-spinning tube, 41-lower ceramic component, 42-upper ceramic component, 43-self-fixed pin, 421-limit lump, 422-holding cambered surface and 423-limit lump. DETAILED DESCRIPTION OF EMBODIMENTS The present invention will now be further illustrated by certain example of embodiments as reported below. The flax grey cloth according to the invention was prepared as shown in Figure 1. Treated flax yarns can be obtained by treating raw flax yarns using the method of untwist and re-twist, and then woven or knitted without any special changes to the manufacture. Shortly, yarns play a quite important role in these procedures. More details about how to prepare the treated flax yarns should follow below steps. Step 1: testing the fibre slipping twists. Direct counting method was applied to determine twist in raw flax yarns (ring spun and rotor spun). Record the cycles when fibre slippage was observed in the untwisting yarns, in other words when the yarn length increased rapidly. It should be noted that rotor spun yarns with too many twists could not be tested in this way. Step 2: measurement of flax fibre principle length (L0) according to corresponding standards. Step 3: measurement of diameter of flax yarns or estimate it according to yarn count. Step 4: adjustment of gauges between rollers and the mini-motor. The total gauge (A plus B in Figure 5) of a preferable embodiment is between 3.0L0 and 5.0L0. The back gauge (A in Figure 5) should be between 1.5L0 and 2.0L0, while the front gauge (B in Figure 5) should be between 1.5L0 and 3.0L0. Step 5: choosing appropriate ceramic components according to the flax yarn diameter. Step 6: determination of draft multiple, the ratio of the back and front rollers. 2024204774   10 Jul 2024 Step 7: calculation of the ratio of the mini-rotor based on the speed of the rollers and the fibre slipping twists. Step 8: run the device. According to the present invention, the key device employed a low power thin mini-motor as shown in Figure 2. The total gauge between the front and back rollers was narrow, and no high power output is required for this action. Holding yarns and not hindering yarn motion are always a conflict, especially for those yarns with low tensile strength. As shown in Figure 3 and 4, the ceramic components had smooth surface, and their suitable curve along with appropriate thickness of limit lumps could supply a solution to the conflict. In addition, the ceramic surfaces had higher resistance to abrasion. During the treatment, the raw flax yarn was firstly untwisted to a certain extent in the area of A in Figure 5 by the mini-motor, and some free fibres could be pulled forward due to different speeds between their heads and ends. At the same time, the mini-motor drove the yarn to rotate in the same direction in the area of B in Figure 5, said giving the twists back to the yarn. In this way, some changes occurred, such as orientation and bendiness of fibres, number of twists per unit length. All of these changes affected together final properties of yarns and fabrics. After physical treatment as above, the treated flax yarns have less twists, lower yarn thickness and higher softness resulting in softer flax cloth. Other properties of yarns and fabrics could also be enhanced depending on different parameter combinations. It was found that the device in the present invention was quite concise and reliable. More importantly, the manufacture process was green, high efficiency and low cost. It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention. While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples 2024204774   10 Jul 2024 are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.

Claims

1. A soft flax cloth, wherein the soft flax cloth is woven or knitted by using soft flax yarns treated on an untwist and re-twist device;the untwist and re-twist device comprises a disc-type mini-motor; during treatment of the soft flax yarns, the rotation direction of the disc-type mini-motor is contrary to the twist direction of the raw flax yarns; and the soft flax yarns treated has the same twist direction as the raw flax yarns but less twists and a lower yarn thickness;the disc-type mini-motor has a hollow inner rotor, the hollow inner rotor has square inner hole, and four holes are defined in four sides of the inner hole, respectively; inside the inner hole there is a self-fixed pin, an upper ceramic component and a lower ceramic component; the upper ceramic component has a raised curved surface in a bottom centre, two limit lumps on two sides of a curved surface and a small hole on a top; and the lower ceramic component has a concave curved surface in a top centre.

2. The soft flax cloth according to claim 1, wherein some or all of the soft flax yarns are soft flax yarns.

3. The soft flax cloth according to claim 1, wherein the disc-type mini-motor has a thickness of 10 mm, and a height of 60 mm.

4. The soft flax cloth according to claim 1, wherein the curved surfaces of the upper and lower ceramic components has a radian between 2 and 3.

5. The soft flax cloth according to claim 1, wherein a gauge between the upper and lower ceramic components is between 0.5 mm and 2 mm, and the gauge can be adjusted by changing the thickness of limit lumps.

6. A method for manufacturing the soft flax yarns according to claim 1 or 2, comprising a step of adjusting the distance between a front draft roller and a back draft roller, wherein,-a total gauge of the front draft roller and the back draft roller is between 3.0L0 and 5.0L0, a gauge of the back draft roller is between 1.5L0 and 2.0L0, and a gauge of the front roller is between 1.5L0 and 3.0L0, and-a rotation speed of the mini-rotor equals a product of a linear speed of the front draft roller and a fibre slipping twist.

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