JP7310168B2 - Method for manufacturing sheet-like material and molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sheet-like material manufacturing method and manufacturing apparatus having a step of unwinding a sheet-like material wound around an unwinding shaft and conveying the sheet-like material through a take-up process.

Conventionally, in processing a continuous sheet-like material, between the unwinding process and the winding process, when performing processing with a batch cycle such as a flat press, for example, the sheet-like material is intermittently transferred to the processing process. is supplied, and the product after processing is intermittently taken back (see, for example, Patent Document 1).

However, there is a problem that the sheet may be broken or elongated depending on the contents of the processing steps, for example, the processing of softening the sheet by heating, or the fluctuation of the process tension during processing. . Here, in the continuous sheet conveying process, a loop of the sheet-like material is formed between the unwinding process and the processing process, and the loop position is controlled to be kept constant, thereby making the unwinding force non-tension. has been proposed (see Patent Document 2, for example).
Japanese Patent Application Laid-Open No. 2004-308098 JP-A-10-81438

The manufacturing process described in Patent Document 2 does not have an intermittent take-up process after the unwinding process. In the intermittent take-up process, the loop position always fluctuates greatly according to the take-up. When the fluctuation becomes too large, rapid rotation and sudden stop are repeated, and excessive slack is generated by inertia. For example, it is difficult to stably convey the sheet-like material because the sheet-like material is damaged.

An object of the present invention is to improve the drawbacks of the continuous processing method by the conventional conveying method, and to manufacture a sheet-like material that can be wound without causing breakage or elongation of the sheet-like material, and a manufacturing apparatus therefor. is to provide

In order to achieve the above object, the present invention provides a method for producing a sheet-like material, comprising a step of intermittently repeating a cycle of unwinding a sheet-like material wound around an unwinding shaft and taking it back, and conveying the sheet-like material, comprising: There is slack in the sheet-like material from the unwinding to the take-up, and out of the slack amount in each cycle, control is performed to keep the slack amount only at the time of completion of take-up within a certain range, and the control is performed by: Provided is a method for producing a sheet-like material, wherein the sheet-like material is rotated by rotating the unwinding shaft so that the amount of the sheet-like material unwound from the unwinding shaft is substantially equal to the amount taken in the take-up step. .

According to the present invention, the sheet-like material from the unwinding process to the take-up process can be made substantially tension-free, and stable sheet conveyance can be realized, so that the sheet-like material can be wound without breaking or stretching. can.

It is a schematic sectional drawing which shows the manufacturing process which concerns on this invention. FIG. 2 is a schematic diagram showing the movement of one cycle of the take-up machine C1 in FIG. 1; FIG. 2 is a schematic diagram showing a relationship between a take-up machine C1 and a slack amount A2 in FIG. 1;

In the method for producing a sheet-like material of the present invention, the unwinding amount and the take-up amount respectively refer to the unwinding length and the take-up length in one cycle in which the sheet-like material wound around the unwinding shaft is unwound and taken up. Point. The unwinding amount is, more specifically, the length of the base material unwound by rotating the unwinding shaft within one cycle, and is not necessarily the same as the take-off amount, but the unwinding amount and the take-off amount are the same. The point of the present invention is to control for the purpose of making them substantially equivalent. Further, the unwinding speed and take-up speed, which will be described later, refer to the length of the base material traveling per unit time in the winding and take-up steps, respectively.

For example, in the processing step between the unwinding step and the take-up step, the strength of the sheet-like material is weakened in the process of being processed, and the sheet-like material breaks unless it is conveyed with substantially no tension. It is advantageous to Therefore, it is particularly advantageous when the material constituting the sheet-shaped article is, in addition to reinforcing fibers, a thermosetting resin that softens during the processing step.

Among the materials constituting the sheet material, thermosetting resins include phenolic resins (including resins using phenols such as cresol, xylenol, and alkylphenol instead of phenol), epoxy resins, unsaturated polyester resins, and melamine. Either resin, polyimide, or the like may be used. It has been confirmed that phenolic resins soften during the processing process, and they are particularly preferred examples to which the present invention is applied. The thermosetting resin may contain particulate matter such as graphite powder and carbon black. As the reinforcing fibers, fibrous materials such as carbon fibers, glass fibers and organic fibers are preferable. In order to prevent the molding material from adhering to equipment in the processing process such as a press, it is preferable to send the molding material to the processing process while sandwiching it between release paper, film, or the like.

When the reinforcing fibers are short fibers, the problem of strength reduction in the processing step becomes even more pronounced, and thus the production method of the present invention is more advantageous, which is preferable.

Next, the unwinding shaft is rotated so that the amount of the sheet-like material unwound from the unwinding shaft becomes substantially equal to the amount of the sheet-like material taken up in the taking-up step, and the sheet-like material when the taking-up is completed. A specific method for keeping the slack amount within a certain range will be described.

A first method is a case where the unwinding shaft is a free roll. Here, a free roll means that the shaft is not connected to a rotational power source, speed-up/deceleration gear, clutch, or other mechanical parts. It is a state in which the force is braked, and it refers to a state in which the shaft rotates freely when it receives a rotational force from an external force, or a shaft that can be in such a state. As a preparatory step, the sheet-like material is wound in advance on the unwinding shaft as two layers together with a protective film. Next, the protective film is passed through a pass line separate from the sheet material and wound up. The protective film rotates around the unwinding shaft due to the tension when the protective film is wound up, and the sheet-like material having the same length as the protective film is unwound. At this time, by setting the take-up speed of the protective film to the average speed of the take-up speed in the take-up step obtained in advance, the amount of the sheet material taken up in the unwinding step is substantially the same as the take-up amount in the take-up step. The unwinding shaft rotates and unwinds so that the range is substantially the same or close. If the amount of slack in the sheet material formed between the unwinding shaft and the take-up process exceeds a certain range, tension is applied to the sheet material between the unwinding process and the take-up process. Due to the elongation of the film and the misalignment between the layers of the protective film and the sheet material, the amount of slack may slightly increase or decrease, resulting in a take-up error. In order to correct this error, in the present invention, only at the time of completion of take-up, i.e., only at the point of time including the time when one cycle of take-up is completed in the take-up process and the amount of slack becomes the smallest, the fluctuation of the slack amount is within a certain range. The take-up speed of the protective film is adjusted so that
Here, since the amount of slack in the sheet material constantly increases and decreases in accordance with the take-up operation in the take-up process, a control method that keeps the amount of slack constant during take-up causes large fluctuations in the take-up speed of the protective film. , the amount of unwinding from the unwinding shaft is not stable, and tension is applied to the sheet-like material, which causes breakage or excessive unwinding, which is not preferable. In other words, as in Patent Document 2, if control is performed to keep the slack amount within a certain range at a time other than the completion of take-up in one cycle, for example, fluctuations in the rotation speed of the unwinding shaft become too large. Since the sheet-like material is damaged by repeating rapid rotation and sudden stop, the object of control is only the completion of the take-up. However, even if the amount of slack is controlled only at the time of completion of pick-up and as a result the amount of slack in one cycle is maintained within a certain range, it shall be included in the present invention. In addition, "only at the time of completion of collection" does not necessarily mean a short period of time. It may be possible to control variations in the amount.
As a second method, there is a method in which the unwinding shaft in the unwinding step in the first method is driven by power. In this method, the roll surface of the sheet material and the protective film wound around the unwinding shaft is constantly rotated so that the unwinding speed of the roll surface becomes equal to the take-up average speed of the take-up step. Since the take-up error also occurs in this method, the rotation speed of the unwinding shaft is adjusted so that the fluctuation of the slack amount is within a certain range at the minimum point of the slack amount in the take-up process.
In the second method as well, the method of controlling the amount of slack in the sheet during one cycle is similarly undesirable. This is because when the number of revolutions of the unwinding shaft fluctuates, the unwinding amount is not stable, and the same tension is applied to break the sheet or unwind it excessively. be.
Here, if a detection step is provided to detect the slack amount of the sheet-like material, and the detected take-up error is automatically adjusted, the take-up error can be absorbed, so that more stable conveyance can be carried out. As a technique for detecting the amount of slack, a non-contact type that does not apply tension to the sheet is preferable. For example, it is more preferable to select an optical sensor such as a laser displacement sensor or an ultrasonic displacement sensor. Information on the detected amount of slack is fed back to the film take-up speed in the first method and to the rotation speed of the unwinding shaft in the second method, thereby absorbing the take-up error.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below based on embodiments shown in the drawings.
FIG. 1 shows an example of implementation of the method of the present invention, comprising an unwinding process A, a processing process B, a take-up process C, a winding process D, and a sheet E. In FIG. The sheet E is conveyed from left to right in FIG.
In the unwinding process A, the slack amount A2 is provided by rotating the unwinding shaft A1 around which the sheet material E is wound in the unwinding direction. The slack amount A2 can be measured using a displacement sensor A3. When the protective sheet A4 is co-wound together with the sheet material E, it can be wound around the protective film take-up shaft A6 via a protective film take-up nip roll. Further, in order to strictly control the unwinding amount, a winding diameter displacement sensor A7 may be installed on the unwinding shaft A1 to measure the winding diameter and feed back the number of revolutions to the unwinding shaft A1.
In the processing step B, the sheet-like material E is subjected to treatments such as heating and pressing (pressing) to obtain a molded product. However, when the sheet-like material E is intermittently taken up in the take-up process C and sent, there is no working external force to resist the take-up, and there is substantially no tension. Moreover, when there is a concern that the sheet-like material E sticks to the processing machine B1, processing can be performed via a release film, a release paper, or the like.
In the take-up process C, as shown in FIG. 2, the take-up machine C1 travels a certain distance from the take-up start position while clamping the sheet E (FIG. 2-1), then stops (FIG. 2-2), and clamps. An intermittent collection cycle is established by releasing (Fig. 2-3) and returning to the starting point in the released state (Fig. 2-4). The taken-up sheet material E is conveyed to the winding process D by the nip roll C2. Here, the amount of slack at the time of completion of the take-over is the amount of slack A2 immediately after the take-up machine moves from the take-up start position C3 to the take-up completion position C4 in FIG. 3, and indicates the minimum slack amount in the take-up cycle.
In the winding process D, the processed sheet material E is wound around the winding shaft D1. When the winding tension on the winding shaft D1 is to be constant, a tensiometer may be installed between the nip roll C2 and the winding shaft D1 in the take-up step.

Hereinafter, examples of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.
[Example 1]
A sheet E was prepared by winding it around the unwinding shaft A1. For the sheet E, a carbon fiber paper (basis weight: 30 g/m 2 ) made from short carbon fibers and impregnated with a phenolic resin (a phenolic resin adhesion rate of 50% by mass based on the basis weight of the sheet) was used. On the sheet material E, a protective film A4 (polyethylene film thickness 10 μm) was wound.
The unwinding shaft A1 was used as a free roll, and the protective film A4 was passed through an independent pass line separate from the sheet E and wound up. At this time, the take-up speed of the protective film A4 (protective film nip roll A5) is set to the average speed of the take-up machine C1 calculated in advance, and the unwinding speed of the sheet E is substantially the average take-up speed of the take-up machine C1. Rotated to be equal. In order to correct slight take-up errors, the slack amount is monitored using the slack amount displacement sensor A3. Feedback was applied to the take-up speed of the protective film. As a result, the sheet-like material E was stably conveyed while maintaining no tension during the processing process, and was wound around the winding shaft D1.
[Example 2]
A sheet E was prepared by winding it around the unwinding shaft A1. The same material as in Example 1 was used for the sheet-like material E. The sheet material E was not wrapped with a protective film.
The unwinding shaft A1 was rotated by a servomotor so that the unwinding speed of the sheet E was substantially equal to the average take-up speed of the take-up machine C1. In order to correct slight take-up errors, the slack amount is monitored using the slack amount displacement sensor A3. A feedback was applied to the rotational speed of the unwinding shaft A1. As a result, the sheet-like material E was stably conveyed while maintaining no tension during the processing process, and was wound around the winding shaft D1.
[Comparative Example 1]
A sheet E was prepared by winding it around the unwinding shaft A1. The same material as in Example 1 was used for the sheet-like material E. A protective film A4 (polyethylene film thickness: 10 μm) was wound around the sheet E.
The unwinding shaft A1 was used as a free roll, and the protective film A4 was passed through an independent pass line separate from the sheet E and wound up. At this time, the take-up speed of the protective film A4 (protective film nip roll A5) was fed back so as to keep the slack amount monitored by the slack amount displacement sensor A3 constant. As a result, the unwinding shaft A1 rapidly rotated and stopped repeatedly in accordance with the movement of the take-up machine C1. The unwinding shaft A1, which is a free roll, rotated excessively due to inertia, resulting in an excessive amount of unwinding and an excessive amount of slack, causing the sheet-like material E to serpentine. When the folded portion entered the processing machine B1, the sheet-like material E was broken.
[Comparative Example 2]
A sheet E was prepared by winding it around the unwinding shaft A1. The same material as in Example 1 was used for the sheet-like material E. Sheet-like material E was not wrapped with a protective film.
Feedback was applied to the unwinding shaft A1 so as to keep constant the slack amount monitored by the slack amount displacement sensor A3 by means of a servomotor. As a result, the unwinding shaft A1 rapidly rotated and stopped repeatedly in accordance with the movement of the take-up machine C1. Under the influence of the sudden stop, the unwinding shaft A1 gradually loosened, the winding collapsed, and the sheet-like material E broke at the distorted portion. When the folded portion entered the processing machine B1, the sheet-like material E was broken.

INDUSTRIAL APPLICABILITY According to the present invention, the present invention can be applied to any process as long as it is a process of intermittently taking a sheet-like material in the take-up process, and its application range is not limited to these.

A Unwinding process B Processing process C Take-up process D Winding process E Sheet material A1 Unwinding shaft A2 Slack amount A3 Slack amount displacement sensor A4 Protective film A5 Protective film winding nip roll A6 Protective film winding shaft A7 Winding diameter displacement sensor B1 processing machine C1 take-up machine C2 take-up nip roll C3 take-up start position C4 take-up completion position D1 take-up shaft

Claims (6)

An unwinding step of unwinding the sheet-like material wound around the unwinding shaft, a retrieving step of intermittently repeating the operation of retrieving the sheet-like material, and conveying the sheet-like material between the unwinding step and the retrieving step. A method for manufacturing a sheet-like material, comprising a processing step of applying heat and pressure to
The sheet material has slack between the unwinding process and the processing process,
Of the slack amount, control is performed to keep the slack amount only at the time of completion of collection within a certain range,
By constantly rotating the control so that the unwinding speed of the sheet-like material is equal to the average speed of the take-up process, the amount of unwinding from the unwinding shaft is substantially equal to the take-up amount in the take-up process. by making them physically equivalent,
Moreover, by not having a mechanism for increasing the tension applied to the sheet-like material from the unwinding process to the take-up process,
A method for producing a sheet-like material, wherein the sheet-like material from the unwinding step to the take-up step is substantially tension-free. 2. The method for producing a sheet according to claim 1, wherein the sheet contains a thermosetting resin and reinforcing fibers. 3. The method for producing a sheet-shaped article according to claim 2, wherein the reinforcing fibers are short fibers. The unwinding shaft is a free roll,
The sheet material is wound around the unwinding shaft in two layers together with a protective film,
4. The method for producing a sheet-like material according to claim 1, wherein the unwinding shaft is rotated by unwinding the protective film. 4. The method for manufacturing a sheet-like material according to claim 1, wherein the unwinding shaft is driven in the unwinding direction by power. 6. The method for producing a sheet-like material according to claim 1, further comprising a detection step of detecting the amount of slack.

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