Thread package and method for manufacturing the thread package

Abstract

To provide a technology related to a yarn package that contributes to reduction of variation in unwinding tension.SOLUTION: A yarn package comprises a bobbin and a yarn that is traversed and wound in an axial direction of the bobbin. The yarn package in which the yarn is unwound in the axial direction of the bobbin includes: a winding yarn part A in which the yarn is wound and a winding yarn part B in which the yarn is wound on an unwinding direction side of the yarn with respect to the winding yarn part A in a half cycle of a traverse; and a part where the winding pitch of the yarn in the winding part B is larger than the winding pitch of the yarn in the winding part A.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a yarn package and a method for making a yarn package. [Background technology]

[0002] Conventionally, a yarn package has been known in which a glass yarn is repeatedly wound on the surface of a winding part of a bobbin from the lower end to the upper end and from the upper end to the lower end, and the winding pitch (a) of the glass yarn when wound from the lower end to the upper end is 0.4 to 0.6 mm, and the winding pitch (b) when wound from the upper end to the lower end is 0.8 to 1.2 mm (see, for example, Patent Document 1). It is said that this yarn package can provide a yarn package and a manufacturing method thereof that are free from yarn breakage and fluff when used as a warp yarn or a weft yarn in weaving a glass cloth, have stable flight properties as a weft yarn, and are free from weaving defects such as short picks and fluff.

[0003] Also, a pirn forming method is known in which, when forming a pirn by reciprocating a wound layer along a bobbin, the wound layer is formed by alternately overlapping wound layers with a sparse winding density and wound layers with a dense winding density (see, for example, Patent Document 2). According to this forming method, if the yarn is pulled out toward the side where the sparsely wound layer is exposed as the top layer and the pirn is unwound, it is said that the risk of unwinding troubles such as loop dropout and twill slippage can be effectively eliminated.

[0004] In addition, in a glass yarn package produced by alternately repeating a process of winding a glass yarn from the bottom to the top of a bobbin and from the top to the bottom of the bobbin, the winding pitch ratio a / R (a is the winding pitch, R is the winding diameter, both in mm) in at least one of the winding processes is 5.0×10 -3 ~16.0×10 -3A glass yarn package characterized by the above is known (see, for example, Patent Document 3). According to this yarn package, since the winding pitch ratio is appropriate, even if the twisting speed of the glass yarn or the unwinding speed of the glass yarn during weaving of the glass cloth is increased, the workability during weaving of the glass cloth is not decreased, and it is said that the deterioration of the quality of the glass cloth can be prevented. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-155588 A [Patent Document 2] Japanese Patent Application Publication No. 64-68528 [Patent Document 3] JP 2003-54837 A Summary of the Invention [Problem to be solved by the invention]

[0006] As a result of investigations by the present inventors, it was found that with yarn packages such as those described in Patent Documents 1 to 3, there was a problem in that the unwinding tension varied when unwinding from the bobbin axial direction, resulting in a decrease in quality when the yarn was made into a woven fabric or other fabric.

[0007] Therefore, a main object of the present invention is to provide a technique relating to a yarn package that solves the above problems and contributes to reducing the variation in unwinding tension. [Means for solving the problem]

[0008] In order to solve the above problem, the inventors of the present invention have focused on the winding pitch. In the present invention, the "winding pitch" refers to the distance between adjacent yarns on the surface of the winding part of the bobbin, that is, the distance between the center lines of the thickness (width) of two adjacent yarns, regardless of the thickness of the yarn, which may vary. The unit of the unit is mm. The winding pitch can be measured by the following measurement method. That is, referring to FIG. 2, a mark is made on the yarn package 1 at the position X where the yarn 2 is wound, and the yarn is unwound from there for 10 revolutions in the circumferential direction of the yarn package, and a mark is made on a position Y parallel to the bobbin axial direction from the position X. Then, the distance (mm) between the positions X and Y is measured, and the winding pitch (mm / revolution) is calculated by dividing the distance (mm) by 10 (revolutions).

[0009] FIG. 1 is a drawing in which FIG. 3 of the above-mentioned Patent Document 1 is cited and the reference numerals are changed. For example, Patent Document 1 describes the following method for manufacturing a yarn package. That is, a cake 4 is set in a twisting machine, a strand 5 is pulled out, and the tip of the strand 5 is first fixed to the lower end of a winding part of a bobbin 3 and wound several times, and the bobbin 3 is set on a spindle 10 to prepare for twisting. In this state, twisting is started, and the strand 5 is twisted to form a yarn 2, and the winding pitch (a) when winding the yarn toward the upper end (shown by a solid line) is 0.4 to 0.6 mm, and the winding pitch (b) when winding the yarn from the upper end to the lower end (shown by a dotted line) is 0.8 to 1.2 mm, starting from the surface of the winding part of the bobbin to form the innermost layer, and then a main winding layer is formed, and a predetermined amount is wound to obtain a yarn package.

[0010] In Fig. 1, an example of a means for adjusting the winding pitch is adjusting the lifting and lowering speed of the ring 9. That is, in Fig. 1, the ring 9 is raised and lowered to perform traverse and build the tapered and straight portions of the yarn package 1, and the winding pitch can be increased by increasing the lifting and lowering speed of the ring 9, and the winding pitch can be decreased by decreasing the lifting and lowering speed of the ring 9.

[0011] In Example 1 of Patent Document 1, the winding pitch (a) when winding the yarn in the upper end direction is 0.49 mm, and the winding pitch (b) when winding the yarn in the lower end direction is 0.98 mm. That is, the winding pitch is constant during a half cycle of traverse (here, in FIG. 1, one cycle of traverse refers to the period from when the ring 9 starts to rise until the ring 9 starts to fall, the ring 9 stops falling, and starts to rise again, and a half cycle refers to the period from when the ring 9 starts to rise and falls until the ring 9 starts to rise and falls, or the ring 9 starts to fall until the ring 9 stops falling and starts to rise). In other words, the rising and falling speeds of the ring 9 are constant when winding the yarn in the upper end direction and when winding the yarn in the lower end direction.

[0012] FIG. 3 is a schematic side view showing a state in which a yarn is unwound from a yarn package in the bobbin axial direction. In FIG. 3, when weaving or the like is performed using the yarn package, the yarn 2 is unwound in the bobbin axial direction (the direction of the arrow in FIG. 3). At this time, the yarn 2 is unwound while undergoing so-called ballooning. Usually, a yarn guide is arranged in the yarn path to suppress ballooning. Here, ballooning affects the tension of the unwound yarn. For example, as shown in FIG. 3, when the yarn 2 is unwound from the lower end of the bobbin 3, the distance from the unwound position to the yarn guide is larger, compared to when the yarn 2 is unwound from the upper end of the bobbin 3, and ballooning becomes larger, and the unwound tension of the yarn 2 also becomes larger.

[0013] The present inventors have found that the variation in the unwinding tension of the yarn package of Patent Document 1 is caused by the difference between the yarn unwinding tension at the upper part (the part on the unwinding direction side) of the yarn package and the yarn unwinding tension at the lower part (the part on the opposite side to the unwinding direction).The present inventors have conducted extensive research and have found that, when the yarn is unwound in the bobbin axial direction, the variation in the unwinding tension can be reduced by configuring the yarn package to include, during half a traverse period, a winding section A around which the yarn is wound and a winding section B around which the yarn is wound on the yarn unwinding direction side of the winding section A, and including a section in which the winding pitch of the yarn at winding section B is larger than the winding pitch of the yarn at winding section A. Specifically, they found that the ballooning is smaller in the winding section B than in the winding section A, and that by making the winding pitch of the winding section B larger than that of the winding section A, for example by changing the lifting and lowering speed of the ring during half a traverse period, the length of the thread wound around the winding section B during the half a traverse period becomes relatively shorter and the length of the thread wound around the winding section A becomes relatively longer, thereby stabilizing the waveform of the unwinding tension and contributing to reducing the variation in the unwinding tension. The present invention was completed based on these findings and through further investigation.

[0014] That is, the present invention provides the following aspects. Item 1. A yarn package including a bobbin and a yarn wound in a traverse direction of the bobbin, the yarn being unwound in the axial direction of the bobbin, the yarn package including, during a half-period of the traverse, a winding section A around which the yarn is wound, and a winding section B around which the yarn is wound on the side of the yarn unwinding direction relative to winding section A, the yarn package including a portion in which the winding pitch of the yarn at winding section B is greater than the winding pitch of the yarn at winding section A. Item 2. The yarn package according to item 1, wherein the winding pitch of the yarn gradually increases from the winding section A toward the winding section B. Item 3. The yarn package according to item 1 or 2, wherein the ratio of the winding pitch of the yarn in the winding section A to the winding pitch of the yarn in the winding section B (winding pitch in winding section B / winding pitch in winding section A) is 1.5 to 10. Item 4. The yarn package according to any one of Items 1 to 3, wherein a winding diameter in the wound yarn section A is larger than a winding diameter in the wound yarn section B. Item 5. The yarn package according to any one of Items 1 to 4, wherein a wound yarn section of the yarn package around which the yarn is wound does not include a portion that has an inverted truncated cone shape relative to an unwinding direction of the yarn. Item 6. The yarn package according to any one of items 1 to 5, wherein the yarn is a glass yarn. Item 7. A method for manufacturing a yarn package in which a yarn is unwound in the axial direction of a bobbin, comprising a step of winding the yarn around the bobbin with a traverse means, the traverse means performing traverse by moving back and forth in the axial direction of the bobbin, and forming a wound yarn section A around which the yarn is wound and a wound yarn section B around which the yarn is wound on the side of the yarn unwinding direction relative to the winding section A during half a period of the traverse, the moving speed of the traverse means in the winding section B being faster than the moving speed of the traverse means in the winding section A. Effect of the Invention

[0015] According to the yarn package of the present invention, a yarn package includes a bobbin and a yarn wound in a traverse direction of the bobbin, and the yarn is unwound in the axial direction of the bobbin. During half a cycle of the traverse, the yarn package includes winding section A around which the yarn is wound, and winding section B around which the yarn is wound on the side of the yarn unwinding direction relative to winding section A, and includes a portion where the winding pitch of the yarn in winding section B is greater than the winding pitch of the yarn in winding section A, which can contribute to reducing variation in unwinding tension. [Brief description of the drawings]

[0016] [Figure 1]FIG. 3 of Patent Document 1 is quoted with new reference numerals, and is a schematic diagram showing an example of a method for manufacturing a yarn package. [Diagram 2] FIG. 4 is a schematic side view illustrating a method for measuring the winding pitch. [Diagram 3] 4 is a schematic side view showing a state in which a yarn is unwound from a yarn package in the axial direction of a bobbin. FIG. [Figure 4] FIG. 2 is a schematic side view showing an example of a bobbin included in the thread package of the present invention. [Diagram 5] FIG. 5 is a schematic side view illustrating the winding pitch of the yarn package of the present invention in half a traverse period, FIG. 5(1) is a schematic side view illustrating the winding pitch of the yarn package of the prior art in half a traverse period, and FIG. 5(2) is a schematic side view illustrating the winding pitch of the yarn package of the present invention in half a traverse period. [Figure 6] FIG. 2 is a diagram illustrating an example of a traverse method. [Figure 7] FIG. 2 is a schematic side view showing an example of a winding shape of the yarn package of the present invention. [Figure 8] FIG. 4 is a schematic diagram for explaining measurement of variation in unwinding tension. [Figure 9] 1 is a measurement graph of the variation in unwinding tension in the outer layer of Example 1. [Figure 10] 1 is a measurement graph of the variation in unwinding tension in the outer layer of Example 3. [Figure 11] 1 is a measurement graph of the variation in unwinding tension in the outer layer of Comparative Example 1. [Figure 12] 1 is a measurement graph of the variation in unwinding tension in the middle layer in Example 1. [Figure 13] 13 is a measurement graph of the variation in unwinding tension in the middle layer in Example 3. [Figure 14] 1 is a measurement graph of the variation in unwinding tension in the middle layer of Comparative Example 1. [Figure 15] 1 is a measurement graph of the variation in unwinding tension in the inner layer of Example 1. [Figure 16]13 is a measurement graph of the variation in unwinding tension in the inner layer of Example 3. [Figure 17] 1 is a measurement graph of the variation in unwinding tension in the inner layer of Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The yarn package of the present invention includes a bobbin and a yarn wound in a traverse direction of the bobbin, the yarn being unwound in the axial direction of the bobbin, and includes a winding section A around which the yarn is wound during a half cycle of the traverse, and a winding section B around which the yarn is wound on the yarn unwinding direction side of the winding section A, the winding pitch of the yarn in winding section B being greater than the winding pitch of the yarn in winding section A. The present invention will be described in detail below.

[0018] <Bobbin> The yarn package of the present invention includes a bobbin for winding a yarn. FIG. 4 is a schematic side view showing an example of a bobbin included in the yarn package of the present invention. In FIG. 4, the bobbin 3 is cylindrical and has a cylindrical hollow portion inside. In FIG. 4, the direction of the arrow is the axial direction of the bobbin 3. The bobbin 3 shown in FIG. 4 includes a flange portion 31, a winding core portion 32 extending from the flange portion 31 in the yarn unwinding direction, and a top portion 33 disposed in the yarn unwinding direction from the winding core portion. In the bobbin 3 shown in FIG. 4, the yarn is unwound in the direction from the flange portion 31 toward the top portion 33 (upward on the paper). For example, when a yarn package is manufactured by the ring twisting machine shown in FIG. 1, the hollow portion can be inserted into the spindle of the ring twisting machine, and the ring of the ring twisting machine is repeatedly raised and lowered (traverse) in the bobbin axial direction, and the yarn package can be manufactured by repeatedly traversing in the bobbin axial direction.

[0019] As shown in Fig. 4, the bobbin 3 included in the thread package of the present invention can have an annular protrusion 321 on the thread winding core 32. The thread winding core 32 can be subjected to various surface treatments, such as matte finish and mirror finish. As shown in Fig. 4, the top 33 of the bobbin 3 included in the thread package of the present invention can include a shoulder 332 and a gripping portion 331. The shoulder 332 can be chamfered.

[0020] Examples of materials for the bobbin include resins such as acrylonitrile-butadiene-styrene copolymer resin, polycarbonate resin, polypropylene resin, and polybutylene terephthalate resin, as well as paper.

[0021] The dimensions of the bobbin 3 are not particularly limited, but examples thereof include a height of the flange portion 31 of 10 to 20 mm, an outer diameter of the flange portion 31 of 120 to 180 mm, and an inner diameter of the flange portion 31 of 50 to 80 mm. Also, examples of the height of the thread winding core portion 32 include a height of 200 to 400 mm, an outer diameter of the thread winding core portion 32 of 60 to 90 mm, and an inner diameter of the thread winding core portion 32 of 50 to 80 mm. Also, examples of the height of the top portion 33 include a height of 50 to 80 mm, etc.

[0022] <Thread> The yarn package 1 of the present invention includes a yarn wound around a bobbin 3 in a traverse direction in the axial direction.

[0023] The yarn 2 contained in the yarn package 1 of the present invention is not particularly limited, but from the viewpoint of making it easier to exhibit the effects of the present invention, a yarn having an elongation of 5% or less is preferable, and glass yarn is particularly preferable. Compared with a yarn having a high elongation, a yarn having a low elongation is difficult to correct defects such as poor appearance of a fabric such as a woven fabric caused by variations in unwinding tension. Therefore, it is necessary to further reduce the variations in unwinding tension during warping and weft insertion for a yarn with low elongation, which further increases the significance of using the yarn package of the present invention. The elongation is measured in accordance with JIS R 3420:2013.

[0024] The form of the yarn 2 contained in the yarn package 1 of the present invention is not particularly limited, but it can be a multifilament composed of a plurality of single fibers. In the case of a glass yarn, it can be a glass yarn. The yarn 2 can be a twisted yarn, and the number of twists can be 0.1 to 1.5 times / 25 mm. The number of twists is measured according to JIS R 3420:2013.

[0025] The yarn count of the yarn 2 contained in the yarn package 1 of the present invention is not limited, but may be, for example, 0.5 to 100 tex, and preferably 0.5 to 5 tex. The length of the yarn 2 contained in the yarn package 1 of the present invention is not limited, but may be, for example, 1 to 1000 km, and preferably 1 to 500 km.

[0026] <Winding pitch in half a traverse period> The yarn package 1 of the present invention includes, during half a traverse period, a winding section A around which a yarn 2 is wound, and a winding section B around which the yarn is wound on the yarn unwinding direction side of the winding section A, and includes a portion in which the winding pitch of the yarn in the winding section B is greater than the winding pitch of the yarn in the winding section A.

[0027] FIG. 5 is a schematic side view illustrating the winding pitch of the yarn package 1 of the present invention in half a traverse period, FIG. 5(1) is a schematic side view illustrating the winding pitch of the yarn package 1 of the prior art in half a traverse period, and FIG. 5(2) is a schematic side view illustrating the winding pitch of the yarn package 1 of the present invention in half a traverse period.

[0028] 5(1) and 5(2), the direction of the arrow indicates the yarn unwinding direction, and includes wound section A around which the yarn 2 is wound, and wound section B around which the yarn 2 is wound on the unwinding direction side of the yarn 2 relative to wound section A (for example, the areas surrounded by dotted lines). The yarn 2 is wound over a half cycle of the traverse.

[0029] Referring to Fig. 5(1), in the yarn package 1 of the prior art, the lifting speed (traverse speed) is constant during half a traverse period, so that the winding pitch of the yarn 2 at winding section B and the winding pitch of the yarn 2 at winding section A during the half a traverse period are equal. On the other hand, referring to Fig. 5(2), in the yarn package 1 of the present invention, the winding pitch of the yarn 2 at winding section B during the half a traverse period is greater than the winding pitch of the yarn 2 at winding section A during the half a traverse period. As a result, the length of the yarn wound around winding section B becomes relatively shorter and the length of the yarn wound around winding section A becomes relatively longer during the half a traverse period, which stabilizes the waveform of the unwinding tension and contributes to reducing the variation in the unwinding tension.

[0030] The position of the wound thread section A in the bobbin axial direction is not particularly limited, but may be, for example, located on the opposite side to the unwinding direction of the thread 2 from the center position of the entire wound thread section (21) in which the thread 2 is wound around the bobbin 3 (the flange 31 side in FIG. 5), and may be in the range of 10% to 50% of the distance measured from the center position of the entire wound thread section in which the thread 2 is wound around the bobbin 3 to the end of the wound thread section on the opposite side to the unwinding direction of the thread 2. The position of the wound thread section B in the bobbin axial direction is not particularly limited as long as it is closer to the unwinding direction of the thread 2 than the center position of the entire wound thread section in which the thread 2 is wound around the bobbin 3, but may be, for example, located on the side of the unwinding direction of the thread 2 from the center position of the entire wound thread section in which the thread 2 is wound around the bobbin 3 (the top side in FIG. 5), and may be in the range of 10% to 50% of the distance measured from the end of the wound thread section on the unwinding direction side of the thread 2.

[0031] Furthermore, there is no particular limitation on the position in the yarn length where there is a half cycle of the traverse including winding section A and winding section B, where the winding pitch of yarn 2 in winding section B is greater than the winding pitch of yarn 2 in winding section A. For example, with respect to the entire length of yarn 2 wound around yarn package 1, the position may be in the range of 5 to 20% of the length measured from the winding start of yarn 2 (the innermost layer side of the yarn package), in the range of 20 to 40% of the length measured from the winding start of yarn 2, in the range of 40 to 60% of the length measured from the winding start of yarn 2, in the range of 60 to 80% of the length measured from the winding start of yarn 2, or in the range of 80 to 100% of the length measured from the winding start of yarn 2. In particular, the position in the yarn length direction where there is a half cycle of the traverse including winding section A and winding section B, where the winding pitch of yarn 2 in winding section B is larger than the winding pitch of yarn 2 in winding section A, is preferably within a range of 5 to 20% of the total length of yarn 2 wound around yarn package 1, measured from the start of winding of yarn 2 (the innermost layer side of the yarn package), more preferably within both the range of 5 to 20% and the range of 40 to 60% or 80 to 100%, particularly preferably within any of the ranges of 5 to 20%, 40 to 60%, and 80 to 100%, and even more preferably always throughout the entire length of yarn 2 wound around yarn package 1. Furthermore, the position in the yarn length where there is a half-period of the traverse including winding section A and winding section B, where the winding pitch of yarn 2 in winding section B is larger than the winding pitch of yarn 2 in winding section A, can be more specifically located within a range of 1 to 10 km from the start of winding (inner layer side), within a range of 50 km to 60 km, within a range of 100 km to 110 km, or within a range of 1 to 10 km from the end of winding (outer layer side).In addition, the direction of the half cycle of the traverse including winding section A and winding section B, in which the winding pitch of the thread 2 in winding section B is greater than the winding pitch of the thread 2 in winding section A, may be at least one of the following directions: from the end of the traverse on the unwinding direction side (the turn point of the traverse on the unwinding direction side) to the other end (the turn point on the opposite side to the unwinding direction side of the traverse) and from the end of the traverse on the opposite side to the unwinding direction (the turn point of the traverse on the opposite side to the unwinding direction side) to the end of the traverse on the unwinding direction side, and it is preferable that it be both of these directions.

[0032] The yarn package 1 of the present invention includes, during a half cycle of traverse, in addition to a winding section A around which the yarn 2 is wound and a winding section B around which the yarn is wound in the yarn unwinding direction relative to winding section A, a winding section C disposed between winding sections A and B in the axial direction of the bobbin 3, and it is preferable that the winding pitch of the yarn 2 in winding section C is larger than the winding pitch of the yarn in winding section A and smaller than the winding pitch of the yarn in winding section B. The position of winding section C in the axial direction of the bobbin 3 is not particularly limited, but may be, for example, the center position of the entire winding section around which the yarn 2 is wound around the bobbin 3.

[0033] In the yarn package 1 of the present invention, the winding pitch in the winding section A is not particularly limited as long as it is smaller than the winding pitch in the winding section B, but for example, it is about 0.1 to 1.0 mm, and preferably about 0.1 to 0.8 mm. In the yarn package 1 of the present invention, the winding pitch in the winding section B is not particularly limited as long as it is larger than the winding pitch in the winding section A, but for example, it is about 1.0 to 3.0 mm, and preferably about 1.3 to 2.5 mm. In the yarn package 1 of the present invention, the winding pitch in the winding section C is, for example, about 0.6 to 1.8 mm, and preferably about 0.9 to 1.2 mm. In addition, the ratio of the winding pitch in the winding section A to the winding pitch in the winding section B (winding pitch in the winding section B / winding pitch in the winding section A) is, for example, preferably 1.5 to 10, more preferably 4 to 8, and even more preferably 5 to 6.

[0034] Furthermore, as shown in FIG. 5(2), the yarn package 1 of the present invention may be one in which the winding pitch of the yarn gradually increases from winding section A toward winding section B.

[0035] Furthermore, in the yarn package 1 of the present invention, the ratio between the winding pitch wound in the unwinding direction of the yarn 2 (corresponding to the winding pitch wound when the ring 9 ascends in FIG. 1) and the winding pitch wound in the opposite direction to the unwinding direction of the yarn 2 (corresponding to the winding pitch wound when the ring 9 descends in FIG. 1) at the same position in the bobbin axial direction is not particularly limited. The ratio (=winding pitch wound on the opposite side to the unwinding direction of the yarn / winding pitch wound in the unwinding direction of the yarn) at the same position in the bobbin axial direction is, for example, 1 / 3 to 3 / 1, and from the viewpoint of reducing variation in unwinding tension, 1 / 2 to 2 / 1 is preferable, and it is more preferable that the winding pitch wound on the opposite side to the unwinding direction of the yarn / winding pitch wound in the unwinding direction of the yarn is 0.8 to 1.2.

[0036] <Ayafuri> In the yarn package 1 of the present invention, the yarn 2 is wound in a traverse manner in the axial direction of the bobbin 3. The traverse manner is not particularly limited. Fig. 6 is a diagram for explaining an example of the traverse manner. In Fig. 6, the thick line indicates the length per cycle of the traverse width (corresponding to the lift amount of the ring 9 in Fig. 1). Examples of the traverse method include the taper top winding method shown in Fig. 6(1), in which the length per traverse cycle gradually increases, and when the length becomes constant, the taper top winding method shown in Fig. 6(2), in which the length per traverse cycle gradually increases or decreases, and when the length becomes constant, the taper top winding method shown in Fig. 6(3), in which the length per traverse cycle is constant, the warp winding method shown in Fig. 6(4), in which the length per traverse cycle gradually decreases, and the differential winding method shown in Fig. 6(5), in which the center position of the traverse cycle changes while the length per traverse cycle remains constant. From the viewpoint of reducing the variation in the unwinding tension, the taper top winding method is preferable.

[0037] <Roll shape> The winding shape of the yarn package 1 of the present invention is not particularly limited. FIG. 7 is a schematic side view showing an example of the winding shape of the yarn package of the present invention. As shown in FIG. 7(1) to (3), for example, the winding shape of the yarn package of the present invention may include a tapered portion in which the winding diameter of the wound yarn part 21 around which the yarn 2 is wound is narrowed toward the unwinding direction side. In addition, it is preferable that the winding diameter of the wound yarn part A is larger than that of the wound yarn part B. In addition, as shown in FIG. 7(1) and (3), the wound yarn part 21 around which the yarn 2 is wound may be only a tapered portion, or as shown in FIG. 7(2), the wound yarn part 21 around which the yarn 2 is wound may include a tapered portion and a straight portion. In addition, it is preferable that the wound yarn part 21 around which the yarn 2 is wound in the yarn package 1 does not include a portion that is an inverted truncated cone shape with respect to the unwinding direction of the yarn 2. In addition, as shown in FIG. 7(3), the tapered portion may be a concave shape. In particular, from the viewpoint of reducing variation in unwinding tension, it is preferable that the winding shape of the yarn package 1 of the present invention be such that the wound yarn portion 21 consists only of a tapered portion, and the tapered portion has a concave shape, as exemplified in Figure 7 (3).

[0038] <Manufacturing method of yarn package> The method for manufacturing the yarn package 1 of the present invention is not particularly limited. For example, the method for manufacturing the yarn package 1 of the present invention may be a method for manufacturing the yarn package 1 in which the yarn 2 is unwound in the axial direction of the bobbin 3, the method including a step of winding the yarn 2 around the bobbin 3 by a traverse means, the traverse means performing traverse by reciprocating in the axial direction of the bobbin 3, forming a wound yarn section A around which the yarn 2 is wound and a wound yarn section B around which the yarn 2 is wound on the unwinding direction side of the yarn 2 relative to the wound yarn section A during a half-period of the traverse, and the moving speed of the traverse means in the winding section B is faster than the moving speed of the traverse means in the winding section A. Hereinafter, an example of manufacturing the yarn package 1 will be described with reference to FIG. 1.

[0039] FIG. 1 is a schematic diagram showing an example of a method for manufacturing a yarn package, citing FIG. 3 of Patent Document 1 with new reference numerals. The ring twisting machine shown in FIG. 1 includes a creel (not shown) for setting a spun cake 4, guides 6 and 7, a ring 9 which is a traverse means that reciprocates in the axial direction of the bobbin 3, a traveler 8 rotatably held by the ring 9, and a spindle 10 which is inserted into the space of the bobbin 3 and fixes and rotates the bobbin 3. First, a spun cake 4 on which a glass strand 5 has been wound is prepared. Then, the spun cake 4 is set on the creel of the ring twisting machine. The rotation speed of the creel can be controlled, and the speed at which the glass strand 5 is sent out from the spun cake 4 can be adjusted by adjusting the rotation speed. The bobbin 3 is also set on the spindle 10. The strand 5 sent out from the cake 4 set on the creel is passed through a guide 7 which adjusts the ballooning height during twisting, and then through the traveler 8, and then wound around the bobbin 3. As the bobbin 3 set on the spindle 10 rotates, the thread 2 (glass yarn) is wound onto the bobbin 3, while the traveler 8 also revolves around the ring 9 to twist the strand 5 into the glass yarn 2.

[0040] The winding pitch can be adjusted mainly by controlling the let-off speed of the yarn 5 (glass strand) from the spun cake 4 and the movement speed (lifting and lowering speed) of the ring 9. For example, in the yarn package 1 of the present invention, to provide a portion where the yarn winding pitch in winding section B is greater than the yarn winding pitch in winding section A, this can be achieved by keeping the yarn let-off speed constant and controlling the lifting and lowering speed of the ring 9 in winding section B to be faster than the lifting and lowering speed of the ring 9 in winding section A.

[0041] <Uses of the yarn package of the present invention> The use of the yarn package 1 of the present invention is not particularly limited. In particular, when the yarn package 1 of the present invention is made into a glass yarn package and used as the warp and weft of a glass cloth for a printed wiring board, it is preferable because it makes it easier to manufacture a glass cloth of uniform quality. Specifically, after weaving, the glass cloth is subjected to an opening process to make the glass cloth smooth. At this time, if the unwinding tension of the warp and weft yarns varies greatly, it is likely that the glass cloth will include parts that are difficult to open and parts that are easy to open, and as a result, the smoothness of the glass cloth is likely to be uneven. On the other hand, the yarn package 1 of the present invention can contribute to reducing the variation in the unwinding tension, and therefore contributes to making the smoothness of the glass cloth more uniform. EXAMPLES

[0042] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the examples.

[0043] 1. Raw yarn As the raw yarn for the yarn package 1, a glass strand 5 (1.7 tex, yarn length 210 km) having a fiber diameter of 4 μm and 50 filaments was wound around a cylindrical tube to prepare a spinning cake 4. 2. Winding device As a device for processing and winding the raw yarn, a ring twisting machine was prepared, as shown in Fig. 1. The ring twisting machine was one capable of controlling the lifting and lowering speed of the ring 9 during a half rotation period of traverse. 3. Bobbin 4 (made of acrylonitrile-butadiene-styrene copolymer resin) was prepared as the bobbin 3 included in the thread package 1. The outer diameter of the thread winding core 32 of the bobbin 3 was 127 mm, and the height of the thread winding core 32 was 210 mm.

[0044] [Example 1] The prepared spun cake 4 was set on the creel of a ring twisting machine, and the glass strand 5 pulled out from the spun cake 4 was passed through a guide and a traveler 8 and wound around a bobbin 3 two or three times, and the bobbin 3 was set on a spindle 10. Then, twisting was performed under the operating conditions set out in Table 1, to obtain a yarn package 1 of the present invention in which the yarn 2 had a length of 200 km. The traverse method used was the taper top winding method shown in Fig. 6(2). Here, the lifting and lowering speed of the ring 9 during half a cycle is set so that the ratio (HV / LV) of the speed LV (m / min) of the bottom end of the thread winding section 21 (the end on the opposite side to the yarn unwinding direction in the bobbin axial direction) to the speed HV (m / min) of the top end of the thread winding section 21 (the end in the yarn unwinding direction in the bobbin axial direction) is 7.50 (i.e., the speed HV of the top end of the thread winding section 21 is 7.5 times the speed LV of the bottom end). When the ring 9 ascends, the speed at each position from the bottom end to the top end of the wound yarn section 21 is gradually increased from the speed LVm / min at the bottom end to the speed HVm / min at the top end, so as to be a value proportional to the axial length of the wound yarn section 21, and when the ring 9 descends, the speed at each position from the top end to the bottom end of the wound yarn section 21 is gradually decreased from the speed HVm / min at the top end to the speed LVm / min at the bottom end, so as to be a value proportional to the axial length of the wound yarn section 21. The shape of the wound yarn section 21 of the obtained yarn package 1 was composed of only a tapered portion, as shown in FIG. 7(3), and the tapered portion had a concave shape. The glass yarn 2 contained in the obtained yarn package 1 had a yarn count of 1.7 tex and a twist number of 0.52 turns / 25 mm.

[0045] [Example 2] The yarn package 1 of the present invention was obtained in the same manner as in Example 1, except that the lifting and lowering speed of the ring 9 during one rotation was set as follows: That is, the lifting and lowering speed of the ring 9 during half a rotation was set so that the ratio (HV / LV) of the speed LV (m / min) of the bottom end of the yarn winding section 21 (the end on the opposite side to the yarn unwinding direction in the bobbin axial direction) to the speed HV (m / min) of the top end of the yarn winding section 21 (the end in the yarn unwinding direction in the bobbin axial direction) was 5.83 (i.e., the speed HV of the top end of the yarn winding section 21 was 5.8 times the speed LV of the bottom end). When the ring 9 ascends, the speed at each position from the bottom end to the top end of the wound yarn section 21 is gradually increased from the speed LVm / min at the bottom end to the speed HVm / min at the top end, so as to be a value proportional to the axial length of the wound yarn section 21, and when the ring 9 descends, the speed at each position from the top end to the bottom end of the wound yarn section 21 is gradually decreased from the speed HVm / min at the top end to the speed LVm / min at the bottom end, so as to be a value proportional to the axial length of the wound yarn section 21. The shape of the wound yarn section 21 of the obtained yarn package 1 was composed of only a tapered portion, as shown in FIG. 7(3), and the tapered portion had a concave shape. The glass yarn 2 contained in the obtained yarn package 1 had a yarn count of 1.7 tex and a twist number of 0.52 turns / 25 mm.

[0046] [Example 3] The yarn package 1 of the present invention was obtained in the same manner as in Example 1, except that the lifting and lowering speed of the ring 9 during one rotation was set as follows: That is, the lifting and lowering speed of the ring 9 during half a rotation was set so that the ratio (HV / LV) of the speed LV (m / min) of the bottom end of the yarn winding section 21 (the end on the opposite side to the yarn unwinding direction in the bobbin axial direction) to the speed HV (m / min) of the top end of the yarn winding section 21 (the end in the yarn unwinding direction in the bobbin axial direction) was 3.75 (i.e., the speed HV of the top end of the yarn winding section 21 is 3.75 times the speed LV of the bottom end). When the ring 9 ascends, the speed at each position from the bottom end to the top end of the wound yarn section 21 is gradually increased from the speed LVm / min at the bottom end to the speed HVm / min at the top end, so as to be a value proportional to the axial length of the wound yarn section 21, and when the ring 9 descends, the speed at each position from the top end to the bottom end of the wound yarn section 21 is gradually decreased from the speed HVm / min at the top end to the speed LVm / min at the bottom end, so as to be a value proportional to the axial length of the wound yarn section 21. The shape of the wound yarn section 21 of the obtained yarn package 1 was composed of only a tapered portion, as shown in FIG. 7(3), and the tapered portion had a concave shape. The glass yarn 2 contained in the obtained yarn package 1 had a yarn count of 1.7 tex and a twist number of 0.52 turns / 25 mm.

[0047] [Comparative Example 1] The prepared spun cake 4 was set on the creel of the ring twisting machine, and the glass strand 5 drawn out from the spun cake 4 was passed through a guide and a traveler 8 and wound around the bobbin 3 for two or three revolutions, and the bobbin 3 was set on the spindle 10. Then, twisting was performed under the operating conditions set as shown in Table 1, to obtain a comparative yarn package 1 having a length of 200 km of the yarn 2. The traverse method was the taper top winding method shown in FIG. 6(1). Here, the lifting speed of the ring 9 during a half rotation period was set so that the ratio (HV / LV) of the speed LV (m / min) of the bottom end of the yarn winding section 21 (the end on the opposite side of the yarn unwinding direction in the bobbin axial direction) to the speed HV (m / min) of the top end of the yarn winding section 21 (the end in the yarn unwinding direction in the bobbin axial direction) was 1.00 (i.e., the speed HV of the top end and the speed LV of the bottom end of the yarn winding section 21 were constant). The ratio of the speed at which the ring 9 ascends to the speed at which the ring 9 descends (speed at which the ring 9 descends / speed at which the ring 9 ascends) was set to 2. The shape of the wound yarn portion 21 of the obtained yarn package 1 was such that the wound yarn portion 21 around which the yarn was wound included a tapered portion and a straight portion, as shown in Fig. 7(2). The glass yarn 2 included in the obtained yarn package 1 had a yarn count of 1.7 tex and a twist number of 0.52 turns / 25 mm.

[0048] (4) Measurement of winding pitch For the yarn packages 1 of Examples 1 to 3 and Comparative Example 1, the winding pitches of the winding sections A and B were measured at a point where the length of the yarn 2 measured from the outermost layer of the yarn package 1 was about 1 km (outer layer), about 100 km (middle layer), and about 200 km (inner layer). The position of the winding section A in the bobbin axial direction (the position where the winding pitch of the winding section A was measured in the bobbin axial direction) was 40 mm from the bottom end of the winding section (the end opposite to the unwinding direction of the yarn 2). The position of the winding section B in the bobbin axial direction (the position where the winding pitch of the winding section B was measured in the bobbin axial direction) was 40 mm from the top end of the winding section (the end on the unwinding direction side of the yarn 2). The winding pitch was measured as described above.

[0049] (5) Measurement of variation in unwinding tension For the yarn packages of Examples 1 to 3 and Comparative Example 1, the variation in unwinding tension was measured at a point where the yarn length was about 1 km (outer layer), about 100 km (middle layer), and about 190 km (inner layer) measured from the outermost layer of the yarn package 1. FIG. 8 is a schematic diagram for explaining the measurement of the variation in unwinding tension. Specifically, the yarn 2 was pulled out from the yarn package 1, and the yarn 2 was set on the pickup 13 of a tension measuring device (manufactured by Yuasa Shido Kogyo Co., Ltd., product name "Tension Analyzer"), and the yarn 2 was run at a yarn speed of 600 m / min using a winding roller 14, and the tension at that time was measured with a sampling period of 100 mSec and a sampling time of 180 seconds. Then, the coefficient of variation (CV) of the obtained measurement data was calculated, and the variation in the unwinding tension was evaluated based on the CV value. In FIG. 8, a guide 12 is provided to prevent the yarn 2 from coming off the pickup 13, and the distance from the top end of the yarn package 1 to the guide 12 is set to 230 mm.

[0050] The physical properties of Examples 1 to 3 and Comparative Example 1 are shown in Table 1. In addition, a measurement graph of the variation in the unwinding tension in the outer layer of Example 1 is shown in Fig. 9, a measurement graph of the variation in the unwinding tension in the outer layer of Example 3 is shown in Fig. 10, a measurement graph of the variation in the unwinding tension in the outer layer of Comparative Example 1 is shown in Fig. 11, a measurement graph of the variation in the unwinding tension in the middle layer of Example 1 is shown in Fig. 12, a measurement graph of the variation in the unwinding tension in the middle layer of Example 3 is shown in Fig. 13, a measurement graph of the variation in the unwinding tension in the middle layer of Comparative Example 1 is shown in Fig. 14, a measurement graph of the variation in the unwinding tension in the inner layer of Example 1 is shown in Fig. 15, a measurement graph of the variation in the unwinding tension in the inner layer of Example 3 is shown in Fig. 16, and a measurement graph of the variation in the unwinding tension in the inner layer of Comparative Example 1 is shown in Fig. 17.

[0051] [Table 1]

[0052] The yarn packages of Examples 1 to 3 include a bobbin and a yarn wound in a traverse direction around the bobbin, and the yarn is unwound in the axial direction of the bobbin. During half a cycle of the traverse, the yarn packages include winding section A around which the yarn is wound, and winding section B around which the yarn is wound in the unwinding direction of the yarn than winding section A, and include a section in which the winding pitch of the yarn in winding section B is larger than the winding pitch of the yarn in winding section A. As a result, the variation in unwinding tension was reduced compared to Comparative Example 1, in which the winding pitch was constant, during half a cycle of the traverse. [Explanation of symbols]

[0053] 1 Yarn Package 2. Thread 21 Winding section 3 Bobbin 31 Flange 32 Thread winding core 321 Circular convex part 33 Top 331 Gripping part 332 Shoulder 4. Spun cake 5 Glass Strands 6, 7 Guide 8. Traveler 9. Ring 10 Spindle 11 Drive belt or motor drive 12 Guide 13 Pickup 14 Winding roller

Claims

1. A yarn package comprising a bobbin and a yarn wound in a traverse direction of the bobbin, the yarn being unwound in the axial direction of the bobbin, A yarn package (excluding those having a constant length per traverse cycle) including a winding section A around which the yarn is wound and a winding section B around which the yarn is wound in the yarn unwinding direction relative to winding section A during half a traverse cycle, and including a portion in which the winding pitch of the yarn in winding section B is greater than the winding pitch of the yarn in winding section A.

2. A yarn package comprising a bobbin and a yarn wound in an axial direction of the bobbin, the yarn being unwound in the axial direction of the bobbin, During a half cycle of the traverse, the winding section includes a winding section A around which the yarn is wound, and a winding section B around which the yarn is wound on the yarn unwinding direction side of the winding section A, and includes a portion in which the winding pitch of the yarn in the winding section B is larger than the winding pitch of the yarn in the winding section A, The yarn is wound in a differential wind manner in which the length of each traverse cycle remains constant while the center position of the traverse cycle changes.

3. 3. The yarn package according to claim 1, wherein a winding pitch of the yarn gradually increases from the winding section A toward the winding section B.

4. The yarn package according to any one of claims 1 to 3, wherein the ratio of the winding pitch of the yarn in the winding section A to the winding pitch of the yarn in the winding section B (winding pitch in winding section B / winding pitch in winding section A) is 1.5 to 10.

5. The yarn package according to any one of claims 1 to 4, wherein a winding diameter in the wound yarn section A is larger than a winding diameter in the wound yarn section B.

6. The yarn package according to any one of claims 1 to 5, wherein a wound yarn portion of the yarn package in which the yarn is wound does not include a portion that has an inverted truncated cone shape relative to an unwinding direction of the yarn.

7. The yarn package according to any one of claims 1 to 6, wherein the yarn is a glass yarn.

8. A method for producing a yarn package according to any one of claims 1 to 7, wherein the yarn is unwound in the axial direction of the bobbin, a step of winding the yarn around the bobbin by a traverse means; The traverse means performs traverse by reciprocating in the axial direction of the bobbin, During a half-period of the traverse, a wound thread portion A around which the yarn is wound and a wound thread portion B around which the yarn is wound on the side of the yarn unwinding direction relative to the wound thread portion A are formed, A method for manufacturing a yarn package, wherein the moving speed of the traverse means in the winding section B is faster than the moving speed of the traverse means in the winding section A.

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