JP7211198B2 - Manufacturing method of carbon fiber fabric - Google Patents

Description

The present invention relates to a method for producing carbon fiber fabrics.

BACKGROUND ART Carbon fiber fabrics are widely used as fiber base materials for fiber-reinforced composite materials used in transportation equipment such as automobiles, ships, and aircraft, and sporting goods. A loom such as a rapier loom is used for manufacturing the carbon fiber fabric. Specifically, a method is known in which a warp sheet consisting of a plurality of warp yarns supplied from a creel is transported, the weft yarns are passed through a shed formed by opening the warp yarns by vertical movement of the heald, and the weft yarns are beaten and wound. ing. In such a method for producing a carbon fiber fabric, the resulting carbon fiber fabric may have a twisted weft due to meandering of the weft, which may deteriorate the appearance of the fiber-reinforced composite material and reduce the strength and rigidity.

It is known that warp tension variation during manufacturing affects the weft weft bending in carbon fiber fabrics. Patent Document 1 discloses a method in which an easing mechanism, in which a contact roller in contact with a warp sheet moves parallel to the roller axis, is provided in front of the heald to reduce tension fluctuations in the warp at the opening and closing opening of the heald, thereby suppressing meandering of the weft. is disclosed.

Japanese Patent Application Laid-Open No. 2008-13900

However, even with the production method as disclosed in Patent Document 1, bending of the weft yarns of the carbon fiber fabric is not sufficiently suppressed, and the appearance of the fiber-reinforced composite material deteriorates, and the strength and rigidity may decrease.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a carbon fiber fabric that can sufficiently suppress weft weft bending, and a tension measuring device used in the method.

The present invention has the following configurations.
[1] A method of manufacturing a carbon fiber fabric using a fabric manufacturing device and a tension measuring device,
The fabric manufacturing apparatus includes a reed, a pressing roll provided downstream of the reed, a winding roll provided downstream of the pressing roll, and a pair of winding rolls provided between the pressing roll and the winding roll. A roll pair consisting of the above nip roll and drive roll,
The roll pair can adjust the contact pressure distribution of the nip rolls in the width direction of the carbon fiber fabric or the warp sheet before starting the production of the carbon fiber fabric or the warp sheet before starting the production of the carbon fiber fabric,
The tension measuring device comprises an indenter in contact with an arbitrary measurement area for 3 to 100 warp yarns in the carbon fiber fabric or warp sheet, a support portion provided so as to surround the circumference of the indenter in the horizontal direction, and the indenter. a load cell for measuring the load applied to the
the position of the lower surface of the support portion is higher than the lower surface of the indenter;
The tension measuring device is placed on the carbon fiber fabric or warp sheet so that the lower surface of the indenter is in contact with the measurement area, and the load cell is applied while the lower surface of the support portion is in contact with the carbon fiber fabric or warp sheet. Convert the read load to obtain the warp tension,
A method for producing a carbon fiber fabric, comprising the following steps (a) to (c).
(a) Between the pressing roll and the drive roll, the warp tension in a plurality of the measurement areas in the width direction of the carbon fiber fabric or the warp sheet is measured by the tension measuring device, and the distribution of the warp tension in the width direction is measured. get
(b) Adjusting the contact pressure distribution based on the warp tension distribution in the width direction obtained in step (a) to equalize the warp tension distribution in the width direction.
(c) After the step (b), weave the carbon fiber fabric.
[2] The above-described item [1], wherein the warp tension is measured by the tension measuring device at three or more locations including a central region in the width direction of the carbon fiber fabric or warp sheet and both end regions. A method for producing a carbon fiber fabric.
[3] The warp tension is measured while the heald is closed in the production of a carbon fiber fabric having a process in which the floating and sinking of all the warp threads are reversed at the same time when the warp threads are opened up and down during weaving, [1] Or the method for producing a carbon fiber fabric according to [2].
[4] After the step (b), the maximum value of the warp yarn tension is 110% or less of the average value of all the measured values of the warp yarn tension measured in the plurality of measurement areas in the width direction, and The method for producing a carbon fiber fabric according to any one of [1] to [3], wherein the minimum warp tension is 90% or more.
[5] The method for producing a carbon fiber fabric according to any one of [1] to [4], wherein the rotation speed of the drive roll is 90 to 99% of the winding speed of the carbon fiber fabric.
[6] The method for producing a carbon fiber fabric according to any one of [1] to [5], wherein the ratio of the amount of warping of the weft to the width of the carbon fiber fabric is 5% or less.
[7] A tension measuring device for measuring warp tension in a carbon fiber fabric or warp sheet,
Measure the load applied to the indenter in contact with an arbitrary measurement area for 3 to 100 warp yarns in the carbon fiber fabric or the warp sheet, the support section provided so as to surround the horizontal periphery of the indenter, and the indenter. a load cell that
the position of the lower surface of the support portion is higher than the lower surface of the indenter;
The tension measuring device is placed on the carbon fiber fabric or warp sheet so that the lower surface of the indenter is in contact with the measurement area, and the load cell is placed with the lower surface of the support portion in contact with the carbon fiber fabric or warp sheet. A tension measuring device that converts the load read from to obtain the warp tension.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the carbon fiber fabric which can fully suppress the bending of a weft, and the tension measuring apparatus used for it can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic diagram which showed an example of the textile manufacturing apparatus used for this invention. FIG. 2 is a plan view of the vicinity of a creel in the fabric manufacturing apparatus of FIG. 1; FIG. 2 is a front view of a roll pair in the fabric manufacturing apparatus of FIG. 1; 1 is a perspective view showing an example of a tension measuring device used in the present invention; FIG. FIG. 5 is a cross-sectional view of the tension measuring device of FIG. 4 taken along line II. FIG. 5 is a schematic diagram showing how the warp tension is measured by the tension measuring device of FIG. 4 ; FIG. 4 is a plan view for explaining the amount of weft bending in the carbon fiber fabric.

A carbon fiber fabric manufacturing method of the present invention is a method of manufacturing a carbon fiber fabric using a specific fabric manufacturing device and a specific tension measuring device. An example of the method for producing the carbon fiber fabric of the present invention will be described below with reference to the drawings.
It should be noted that the dimensions and the like of the drawings illustrated in the following description are only examples, and the present invention is not necessarily limited to them, and can be implemented with appropriate changes within the scope of not changing the gist of the present invention. .

(textile manufacturing equipment)
The fabric manufacturing apparatus used in the present invention includes a reed, a pressing roll provided downstream of the reed, a winding roll provided downstream of the pressing roll, and at least one pair provided between the pressing roll and the winding roll. and a roll pair consisting of a drive roll and a nip roll. Further, the roll pair is configured to adjust the contact pressure distribution of the nip rolls in the width direction of the carbon fiber fabric or the warp sheet before the production of the carbon fiber fabric or the warp sheet is sandwiched. .

An example of the textile manufacturing apparatus will be shown and described in more detail below.
As shown in FIG. 1, the fabric manufacturing apparatus 100 of the present embodiment includes a creel 104 having a plurality of bobbins 102, a drive roll 110, a warp tensioner roll 112, a heald 114, a reed 116, and a pressure roll 118. , a roll pair 124 consisting of a nip roll 120 and a driving roll 122, and a take-up roll 126, in this order. Between the heald 114 and the reed 116 a weft insertion means 128 is provided.
A weaving section 129 is composed of the heald 114 , the reed 116 , the pressure roll 118 and the weft insertion means 128 .

A plurality of guide rolls 130 are provided between the creel 104 and the drive roll 110 to guide the transport of the warp sheet 2 . A comb 138 is provided between the creel 104 and the guide roll 130 .
The comb 138 comprises a plurality of vertically spaced cylindrical bars. By passing the warp yarns 1 between the bars of the comb 138, the positions of the conveyed warp yarns 1 in the width direction are regulated.

As shown in FIGS. 1 and 2 , in the fabric manufacturing apparatus 100 , a plurality of warp threads 1 are wound from a plurality of bobbins 102 on a creel 104 . A comb 138 downstream of the creel 104 narrows the distance between the plurality of warp yarns 1 in the width direction, forming a warp yarn sheet 2 having a width equal to the weaving width. The formed warp sheet 2 is then guided to the weaving section 129 via the drive roll 110 and the warp tensioner roll 112 . Each warp 1 of the warp sheet 2 guided to the weaving section 129 is passed through each of a plurality of healds 114 arranged in the width direction.

Each heald 114 can be individually moved up and down with the warp thread 1 threaded therethrough. In addition, all the warp threads 1 in the width direction of the warp sheet 2 are pressed from above by pressing rolls 118 behind each heald 114 . As a result, each heald 114 is vertically moved to open the warp sheet 2 so that each warp 1 is vertically opened between each heald 114 and the pressing roll 118 . Next, in the weft insertion means 128, the weft 3 unwound from the bobbin 140 is passed by a rapier 142 through a shed formed by opening the warp sheet 2 vertically. After the weft 3 is beaten by the reed 116, each heald 114 moves up and down to form the next shed. Such operations are repeated to form the carbon fiber fabric 4 .

The manner of vertical movement of each heald 114, the number of weft threads to be inserted into each shed, and other settings can be appropriately determined according to the weave structure of the carbon fiber fabric 4 to be manufactured.
The weft insertion means 128 is not limited to means using a rapier, and may be means for passing the weft through the shed using a shuttle, a gripper, an air jet, a water jet, or the like. The weft 3 is not limited to carbon fiber, and may be aramid fiber, glass fiber to which thermoplastic resin is welded, or the like.

The formed carbon fiber fabric 4 is taken up by a roll pair 124 consisting of a nip roll 120 and a drive roll 122 and wound around a take-up roll 126 .

In the roll pair 124, as shown in FIG. 1 and FIG. A nip roll 120 is installed thereon. When the carbon fiber fabric 4 is taken up by the roll pair 124, the carbon fiber fabric 4 is wound around the nip roll 120 from above and guided between the nip roll 120 and the driving roll 122 to be sandwiched.

The roll pair 124 can adjust the contact pressure distribution of the nip rolls 120 in the width direction of the carbon fiber fabric 4 or the warp sheet 2 before starting the production of the carbon fiber fabric 4 or the warp sheet 2 before the production of the carbon fiber fabric 4 is started. It's like Specifically, in this example, as shown in FIG. 3, springs 121, 121 are provided on both ends of the shaft 120a of the nip roll 120, respectively. The respective springs 121, 121 are connected to screws 123, 123 attached to a base 125, and the expansion and contraction of the respective springs 121, 121 can be adjusted by the degree of tightening of the screws 123, 123.

For example, when one screw 123 is tightened and the other screw 123 is loosened, the expansion and contraction of the spring 121 increases the downward force applied to one end of the shaft 120a of the nip roll 120, causing the one end to move downward. The force applied to the is weakened. As a result, the contact pressure on the carbon fiber fabric 4 or the warp sheet 2 on the side of the nip roll 120 where the screws 123 are tightened increases, and the contact pressure on the opposite side decreases.

When both screws 123 are tightened, the downward force applied to both ends of the shaft 120a of the nip roll 120 increases, and the contact pressure of the both end regions of the nip roll 120 to the carbon fiber fabric 4 or the warp sheet 2 increases. On the other hand, since the shaft 120a of the nip roll 120 is curved upward, the contact pressure of the center region of the nip roll 120 in the width direction against the carbon fiber fabric 4 or the warp sheet 2 is reduced.

The warp tension of the warp sheet 2 in the weaving section 129 is determined by the speed difference between the rotational speed of the driving roll (dummy roll) 110 and the rotational speed of the driving roll (take-up roll) 122 and the winding roll 126, and the carbon fiber fabric 4 of the nip roll 120. Or the contact pressure on the warp sheet 2 has an effect.

Specifically, if the speed difference between the driving roll 110 and the driving roll 122 or the speed difference between the driving roll 110 and the take-up roll 126 is large, the overall warp tension in the weaving section 129 increases, and if the speed difference is small, , the warp tension in the weaving section 129 is reduced as a whole.
In addition, the greater the contact pressure of the nip rolls 120 on the carbon fiber fabric 4 or the warp sheet 2, that is, the greater the force with which the nip rolls 120 and the driving rolls 122 pinch the carbon fiber fabric 4 or the warp sheet 2, the greater the warp tension in the weaving section 129. , the influence of the take-up roll 126 is reduced and the influence of the drive roll 122 is increased. Therefore, by adjusting the contact pressure distribution of the nip rolls 120 in the width direction of the carbon fiber fabric 4 or the warp sheet 2, the degree of influence of the drive roll 122 and the winding roll 126 on the warp tension in the width direction of the weaving section 129 changes, and the distribution of the warp tension in the width direction changes.

In addition, the textile manufacturing apparatus used in the present invention is not limited to the textile manufacturing apparatus 100. FIG. For example, the number of roll pairs is not limited to one pair, and two or more roll pairs may be provided between the pressing roll and the take-up roll.

(Tension measuring device)
A tension measuring device is a device for measuring the warp tension in a carbon fiber fabric or warp sheet.
The tension measuring device comprises an indenter in contact with an arbitrary measurement area for 3 to 100 warp threads in a carbon fiber fabric or warp sheet, a support section provided to surround the indenter in the horizontal direction, and a load applied to the indenter. a measuring load cell. The lower surface of the support portion is positioned higher than the lower surface of the indenter. In the measurement of warp tension using a tension measuring device, the tension measuring device is placed on the carbon fiber fabric or warp sheet so that the lower surface of the indenter is in contact with the measurement area, and the lower surface of the support portion is in contact with the carbon fiber fabric or warp sheet. The warp yarn tension is obtained by converting the load read from the load cell in the state in which the warp tension is read based on the result of the calibration carried out in advance.

An example of the tension measuring device will be shown and described in more detail below.
As shown in FIGS. 4 and 5 , the tension measuring device 200 of this embodiment includes an indenter 202 , an annular plate-shaped support portion 204 , a load cell 206 , and a support portion 208 .

The support portion 208 includes an annular portion 210 , a cross-shaped bridging portion 212 provided inside the annular portion 210 , a pressing portion 214 projecting upward from the central portion of the bridging portion 212 , and the annular portion 210 . and four posts 216 of equal length depending from the bottom surface. The four pillars 216 are arranged at equal angular intervals around the center of the annular portion 210 in plan view.

A load cell 206 is connected below the central portion of the bridge portion 212 in the support portion 208 . An indenter 202 is connected below the load cell 206 . The load cell 206 can read the load applied upward to the lower surface 202 a of the indenter 202 .
The size of the lower surface 202a of the indenter 202 is adjusted so that it contacts a measurement area of 3 to 100 warp threads in the carbon fiber fabric or warp sheet.

The lower ends of the four pillars 216 of the support section 208 are connected to the support section 204 respectively. The support portion 204 is provided so as to surround the indenter 202 in the horizontal direction, and the lower surface 204 a of the support portion 204 is positioned higher than the lower surface 202 a of the indenter 202 .

A distance d in the height direction between the lower surface 204a of the support portion 204 and the lower surface 202a of the indenter 202 is preferably 0.1 to 10 mm, more preferably 0.5 to 2.0 mm, and even more preferably 0.8 to 1.2 mm. . If the distance d is within the above range, the widthwise distribution of the warp tension in the carbon fiber fabric or warp sheet can be easily measured.

The distance f from the center of the indenter 202 to the support portion 204 in the warp direction on the carbon fiber fabric or warp sheet is preferably 1 time or more, more preferably 2 to 10 times, more preferably 2 to 10 times the width of the indenter 202 in the warp direction. Three times is more preferred. If the distance f is equal to or greater than the lower limit of the above range, the error in the warp tension measurement value due to the deviation of the load on the indenter from the vertical direction can be reduced to a negligible extent. If the distance f is equal to or less than the upper limit of the above range, handling of the device becomes easy.

The mass of the tension measuring device is preferably 10-500 g, more preferably 20-200 g, even more preferably 30-100 g. If the mass is at least the lower limit of the above range, the device can have sufficient strength and rigidity to withstand handling. If the mass is equal to or less than the upper limit of the above range, errors in warp tension measurement values due to errors in load cell readings can be made negligible.

Measurement of warp tension using the tension measuring device 200 will be described.
As shown in FIG. 6, the tension measuring device 200 is placed on the carbon fiber fabric 4 so that the lower surface 202a of the indenter 202 is in contact with the measurement area of the carbon fiber fabric 4. As shown in FIG. At this time, if the lower surface 204a of the support portion 204 is in contact with the carbon fiber fabric 4, the load is read from the load cell 206 in that state, and the warp tension is obtained by converting the load. If the lower surface 204a of the support portion 204 is not in contact with the carbon fiber fabric 4 when the tension measuring device 200 is placed thereon, the pressing portion 214 of the support portion 208 is pushed until the lower surface 204a of the support portion 204 is in contact with the carbon fiber fabric 4. downwards. Then, while the lower surface 204a of the support portion 204 is in contact with the carbon fiber fabric 4, the load is read from the load cell 206, and the warp yarn tension is obtained by converting the load.

The measurement of the warp tension in the warp sheet before starting the production of the carbon fiber fabric can be performed in the same manner as the measurement of the warp tension of the carbon fiber fabric.
In the measurement of the warp tension, "the lower surface of the support is in contact with the carbon fiber fabric or the warp sheet" means that the lower surface of the support is in contact with the carbon fiber fabric or the warp sheet over the entire circumference. A state in which the measuring device is tilted and only a part of the lower surface of the support portion in the circumferential direction is in contact with the carbon fiber fabric or the warp sheet is not included.

The tension measuring device used in the present invention is not limited to the tension measuring device 200. For example, the support portion is not limited to an annular shape, but a rectangular annular shape, or a set of two rectangular shapes arranged on both sides of the indenter in the horizontal direction so that the surfaces are parallel to each other with the indenter as the center. may be

(Production method)
The method for producing a carbon fiber fabric of the present invention is a method having the following steps (a) to (c).
(a) Between the pressure roll and the drive roll of the roll pair, the warp tension in a plurality of measurement areas in the width direction of the carbon fiber fabric or warp sheet is measured by a tension measuring device to obtain the distribution of the warp tension in the width direction.
(b) Based on the warp tension distribution in the width direction obtained in step (a), the contact pressure distribution of the nip rolls in the width direction of the carbon fiber fabric or warp sheet is adjusted to equalize the warp tension distribution in the width direction. do.
(c) Weave a carbon fiber fabric after step (b).

Hereinafter, as an example of the carbon fiber fabric manufacturing method of the present invention, a method using the fabric manufacturing apparatus 100 and the tension measuring apparatus 200 will be described.
In step (a), the warp tension of the carbon fiber fabric 4 or the warp sheet 2 is measured by the tension measuring device 200 between the pressing roll 118 and the drive roll 122 of the fabric manufacturing apparatus 100 . More specifically, the tension measuring device 200 measures the warp tension in the carbon fiber fabric 4 or the warp sheet 2 between the pressure roll 118 and the nip roll 120 .

Before starting the production of the carbon fiber fabric, a plurality of warp yarns 1 are unwound from a plurality of bobbins 102 of the creel 104 to form a warp yarn sheet 2, and the warp yarn tension is set at the stage where the warp yarn sheet 2 is wound up to the winding roll 126 to prepare for production. measurement.
When the production of the carbon fiber fabric is stopped halfway and the production is restarted, the warp tension of the carbon fiber fabric 4 between the pressure roll 118 and the nip roll 120 is measured while the production is stopped.

The measurement of the warp tension in step (a) is performed on a plurality of measurement regions in the width direction of the carbon fiber fabric 4 or the warp sheet 2 . Specifically, in the width direction of the carbon fiber fabric 4 or the warp sheet 2, the warp tension is measured multiple times while shifting the position where the tension measuring device 200 is placed. Then, the distribution of the warp tension in the carbon fiber fabric 4 or the warp sheet 2 in the width direction is obtained from the warp tension measured in a plurality of measurement areas.

It is preferable that the warp tension is measured by the tension measuring device at three or more points including the center area and both side end areas in the width direction of the carbon fiber fabric or warp sheet. As a result, the distribution of the warp tension in the width direction becomes more dense, and the accuracy of equalizing the distribution of the warp tension in the width direction in step (b) increases.

The number of warp tension measurement regions by the tension measuring device is preferably 3 or more, more preferably 3 to 9, and even more preferably 3 to 5, depending on the width of the carbon fiber fabric or warp sheet. If the number of measurement regions is equal to or greater than the lower limit of the above range, the obtained warp tension distribution in the width direction will be more precise. In addition, in the width direction, even in the case of a tension distribution in which the warp yarn tension is high in both end regions and the warp yarn tension is low in the central region, it is easy to detect it. If the number of measurement areas is equal to or greater than the lower limit of the above range, the warp tension can be easily measured in a short period of time.

The number of warp threads included in one measurement area is preferably 3 to 100, more preferably 5 to 20, and even more preferably 6 to 12. If the number of warp yarns is at least the lower limit of the above range, even if some warp yarns are locally subjected to excessive or insufficient tension, the measurement results are less affected by them, and the average warp tension is small deviation from If the number of warp threads is equal to or less than the upper limit of the range, it is possible to obtain a warp tension distribution with high spatial resolution.

The warp and weft in the carbon fiber fabric are 1KCF with 1000 filaments in the tow, 3KCF with 3000 filaments in the tow, and 6000 filaments in the tow. 6KCF, 12KCF in which the number of filaments contained in the tow is 12,000, 15KCF in which the number of filaments contained in the tow is 15,000, 50KCF in which the number of filaments contained in the tow is 50,000, and the like can be used.

The warp density in the carbon fiber fabric is preferably in the range of 0.5 to 2 times the toe width when the warp is not restrained when the warp is not opened. is preferably in the range of 2 to 6 times the tow width in the unconstrained state of the warp yarns before opening.
Since the indenter of the tension measuring device preferably contains 6 to 12 warp threads, a circular indenter diameter or a rectangular The width of the indenter in the weft direction is preferably w × 3 to w × 24 mm for carbon fiber fabrics without fiber spreading, and w × 12 to w × 72 mm for carbon fiber fabrics with fiber spreading. is preferred.

Specifically, the unconstrained tow width of 1KCF is usually 0.84 mm, and the warp density of the carbon fiber fabric using 1KCF without opening is 0.42 to 1.68 mm/ is a book. In this case, a circle with a diameter of 2.5 to 20.2 mm or a rectangle with a width of 2.5 to 20.2 mm in the weft direction is preferably used as the indenter of the tension measuring device.
The unrestrained tow width of 3KCF is usually 1.6 mm, and the warp density of the carbon fiber fabric using 3KCF without opening is 0.8-3.2 mm/thread. In this case, a circle with a diameter of 4.8 to 38.4 mm or a rectangle with a width of 4.8 to 38.4 mm in the weft direction is preferably used as the indenter of the tension measuring device.

The unrestrained tow width of 6KCF is usually 2.0 mm, and the warp density of carbon fiber fabric using 6KCF without opening is 1.0 to 4.0 mm/thread. In this case, a circle with a diameter of 6.0 to 48.0 mm or a rectangle with a width of 6.0 to 48.0 mm in the weft direction is preferably used as the indenter of the tension measuring device. The warp density of the carbon fiber fabric using 6KCF when opening is 4.0 to 12 mm/thread. In this case, a circle with a diameter of 24.0 to 144.0 mm or a rectangle with a width of 24.0 to 144.0 mm in the weft direction is preferably used as the indenter of the tension measuring device.

The unconstrained tow width of 12KCF is usually 3.0 mm, and the warp density of the carbon fiber fabric using 12KCF without opening is 1.5-6.0 mm/thread. In this case, a circular indenter with a diameter of 9.0 to 72.0 mm or a rectangular indenter with a width of 9.0 to 72.0 mm in the weft direction is preferably used as the indenter of the tension measuring device. The warp density of the carbon fiber fabric using 12KCF when opening is 6.0 to 18 mm/thread. In this case, a circle with a diameter of 36.0 to 216.0 mm or a rectangle with a width of 36.0 to 216.0 mm in the weft direction is preferably used as the indenter of the tension measuring device.

The unconstrained tow width of 15KCF is usually 3.4 mm, and the warp density of carbon fiber fabric using 15KCF without opening is 1.7-6.8 mm/thread. In this case, a circle with a diameter of 10.2 to 81.6 mm or a rectangle with a width of 10.2 to 81.6 mm in the weft direction is preferably used as the indenter of the tension measuring device. The warp density of the carbon fiber fabric using 15KCF when opening is 6.8 to 20.4 mm/thread. In this case, a circle with a diameter of 40.8 to 244.8 mm or a rectangle with a width of 40.8 to 244.8 mm in the weft direction is preferably used as the indenter of the tension measuring device.

The unconstrained tow width of 50KCF is usually 16 mm, and the warp density of the carbon fiber fabric using 50KCF without opening is 8.0-32 mm/thread. In this case, a circle with a diameter of 48.0 to 384.0 mm or a rectangle with a width of 48.0 to 384.0 mm in the weft direction is preferably used as the indenter of the tension measuring device.

A process in which the floating and sinking of all warp threads are reversed at the same time when the warp threads are opened up and down during weaving, such as plain weave, 2/2 weft weave, 2/2 nanako weave, etc. If so, it is preferable to measure the warp tension with the healds closed, ie with the healds aligned horizontally. As a result, the influence of the heald on the warp yarn tension is reduced, so that the weft yarn bending suppression effect obtained when the yarn tension distribution in the width direction is made uniform increases.

In the step (b), the contact pressure distribution of the nip rolls 120 in the width direction of the carbon fiber fabric 4 or the warp sheet 2 is adjusted based on the warp tension distribution in the width direction obtained in the step (a). To homogenize the distribution of the warp tension in the width direction.

For example, the rotation speed of the take-up roll 126 is faster than the rotation speed of the drive roll 122, and the warp tension in both end regions in the width direction of the carbon fiber fabric 4 or the warp sheet 2 in the weaving section 129 is higher than the warp tension in the central region. If it is too large, adjust as follows. Both screws 123 are tightened to increase the contact pressure on the carbon fiber fabric 4 or the warp sheet 2 in both end regions of the nip roll 120 and decrease the contact pressure in the central region. As a result, the influence of the take-up roll 126 on the warp tension is reduced in both end regions of the carbon fiber fabric 4 or the warp sheet 2 in the width direction, thereby reducing the warp tension. On the other hand, in the central region in the width direction, the winding roll 126 exerts a greater influence on the warp tension, so that the warp tension increases. As a result, the distribution of the warp tension of the carbon fiber fabric 4 or the warp sheet 2 in the weaving section 129 in the width direction is made uniform.

Further, the rotation speed of the take-up roll 126 is faster than the rotation speed of the drive roll 122, and as the carbon fiber fabric 4 or the warp sheet 2 in the weaving section 129 moves from one end in the width direction to the other end, If the warp tension becomes small, adjust as follows. Tighten the screw 123 on the side where the warp tension is high and loosen the screw 123 on the opposite side to increase the contact pressure of the nip roll 120 on the carbon fiber fabric 4 or the warp sheet 2 on the side where the warp tension is high. to be smaller. As a result, in the width direction, on the side where the warp tension was high, the influence of the winding roll 126 on the warp tension is reduced, and the warp tension is reduced. On the other hand, in the width direction, on the side where the warp tension was low, the influence of the winding roll 126 on the warp tension increases, and the warp tension increases. As a result, the distribution of the warp tension of the carbon fiber fabric 4 or the warp sheet 2 in the weaving section 129 in the width direction is made uniform.

After equalizing the distribution of the warp tension in the width direction in the step (b), the maximum value of the warp tension is 110 with respect to the average value of all the measured values of the warp tension measured in a plurality of measurement areas in the width direction. % or less, and the minimum warp tension is preferably 90% or more. This makes it possible to obtain a carbon fiber woven fabric with a small weft twist.

Thereafter, in step (c), the carbon fiber fabric 4 is woven.
The rotation speed of the drive roll 122 in the roll pair 124 is preferably 90 to 99%, more preferably 97 to 99%, of the winding speed of the carbon fiber fabric 4, that is, the rotation speed of the winding roll 126. If the rotation speed of the drive roll 122 is within the above range, the contact pressure distribution of the nip rolls 120 in the width direction of the carbon fiber fabric 4 or the warp sheet 2 is adjusted to uniform the distribution of the warp tension in the weaving section 129 in the width direction. becomes easier to convert.

The ratio of the warp amount W (mm) of the weft to the width D (mm) of the carbon fiber fabric manufactured by the manufacturing method of the present invention is preferably 5% or less, more preferably 1% or less.
The warp amount W of the weft yarn means the distance (mm) in the longitudinal direction of the warp yarn 1 in the region S occupied by the weft yarn 3 in the plan view of the carbon fiber fabric 4 having the width D (FIG. 7). The weft warp amount W is obtained by measuring the warp amounts of arbitrary four wefts in the carbon fiber fabric and averaging them.

The distribution of the warp tension in the width direction affects the amount of weft bending in the produced carbon fiber fabric.
For example, as in the fabric manufacturing apparatus 100 (FIG. 2) described above, in the production of a carbon fiber fabric by a loom, generally, the width of the creel is larger than the width of the carbon fiber fabric, and a plurality of windings unwound from each bobbin of the creel. The distance between the warp threads is reduced to form a warp sheet. In this case, in the width direction of the warp sheet, warp tension tends to be greater in both end regions than in the central region because the warp embracing angle of the creel battens and combs is larger. Therefore, as shown in FIG. 7(A), a carbon fiber fabric 4 in which the weft 3 is curved in a bow shape is easily obtained.

Further, when the axis of a roll, such as a guide roll, which is in contact with the warp sheet being conveyed is tilted with respect to the width direction of the warp sheet, the warp tension on the end side tilted downstream of the roll in the width direction is vice versa. tend to be greater than the side warp tension. In this case, as shown in FIG. 7(B), a carbon fiber fabric 4 in which the weft threads 3 are skewed is likely to be obtained.

In contrast, in the present invention, the contact pressure distribution in the width direction of the nip rolls is adjusted based on the distribution in the width direction of the warp yarn tension measured using a tension measuring device between the pressure roll and the drive roll of the roll pair. to uniformize the distribution of the warp tension in the width direction. As a result, it is possible to sufficiently suppress the bending of the weft in the manufactured carbon fiber fabric. Therefore, deterioration of the appearance of the fiber-reinforced composite material and deterioration of strength and rigidity can be suppressed. In addition, the method of measuring tension using the tension measuring device can also be used for fibers other than carbon fibers, such as glass fibers and aramid fibers.

DESCRIPTION OF SYMBOLS 1... Warp, 2... Warp sheet, 3... Weft, 4... Carbon fiber fabric, 100... Textile manufacturing apparatus, 114... Held, 116... Reed, 118... Press roll, 120... Nip roll, 122... Drive roll (take-up roll) , 124 Roll pair 126 Winding roll 128 Weft insertion means 129 Weaving section 200 Tension measuring device 202 Indenter 202a Lower surface of indenter 204 Support section 204a Lower surface of support section , 206 ... load cell, 208 ... support portion, D ... width of carbon fiber fabric, W ... amount of warp of weft.

Claims (6)

A method for manufacturing a carbon fiber fabric using a fabric manufacturing device and a tension measuring device,
The fabric manufacturing apparatus includes a reed, a pressing roll provided downstream of the reed, a winding roll provided downstream of the pressing roll, and a pair of winding rolls provided between the pressing roll and the winding roll. A roll pair consisting of the above nip roll and drive roll,
The roll pair can adjust the contact pressure distribution of the nip rolls in the width direction of the carbon fiber fabric or the warp sheet before starting the production of the carbon fiber fabric or the warp sheet before starting the production of the carbon fiber fabric,
The tension measuring device comprises an indenter in contact with an arbitrary measurement area for 3 to 100 warp yarns in the carbon fiber fabric or warp sheet, a support portion provided so as to surround the circumference of the indenter in the horizontal direction, and the indenter. a load cell for measuring the load applied to the
the position of the lower surface of the support portion is higher than the lower surface of the indenter;
The tension measuring device is placed on the carbon fiber fabric or warp sheet so that the lower surface of the indenter is in contact with the measurement area, and the load cell is applied while the lower surface of the support portion is in contact with the carbon fiber fabric or warp sheet. Convert the read load to obtain the warp tension,
A method for producing a carbon fiber fabric, comprising the following steps (a) to (c).
(a) Between the pressing roll and the drive roll, the warp tension in a plurality of the measurement areas in the width direction of the carbon fiber fabric or the warp sheet is measured by the tension measuring device, and the distribution of the warp tension in the width direction is measured. get
(b) Adjusting the contact pressure distribution based on the warp tension distribution in the width direction obtained in step (a) to equalize the warp tension distribution in the width direction.
(c) After the step (b), weave the carbon fiber fabric. 2. The carbon fiber fabric according to claim 1, wherein the warp tension is measured by the tension measuring device at three or more locations including a central region in the width direction of the carbon fiber fabric or warp sheet and both end regions. manufacturing method. 3. In manufacturing a carbon fiber fabric having a step in which floating and sinking of all warp threads are reversed at the same time when the warp threads are opened vertically during weaving, the warp thread tension is measured with the heald closed. A method for producing the carbon fiber fabric described. After the step (b), the maximum value of the warp yarn tension is 110% or less of the average value of all the measured values of the warp yarn tension measured in the plurality of measurement areas in the width direction, and the warp yarn tension The method for producing a carbon fiber fabric according to any one of claims 1 to 3, wherein the minimum value is 90% or more. The method for producing a carbon fiber fabric according to any one of claims 1 to 4, wherein the rotation speed of the drive roll is 90 to 99% of the winding speed of the carbon fiber fabric. The method for producing a carbon fiber fabric according to any one of claims 1 to 5, wherein the carbon fiber fabric is produced so that the ratio of the amount of warping of the weft to the width of the carbon fiber fabric is 5% or less.

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