JP2017113987A - Method for producing prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a prepreg capable of suppressing a change in a resin amount impregnated in a fiber bundle even when a width of the fiber bundle changes.SOLUTION: A method for producing a prepreg includes: a step of measuring a width of a carbon fiber bundle 10 before impregnated with a resin E; and a method for controlling a blade 30, which is arranged so as to be close to the surface of a resin-impregnated roll R impregnated with the resin E and can adjust an interval with the surface of a resin-impregnated roll R, according to a width of the measured carbon fiber bundle 10 and a weight of the carbon fiber bundle 10, and thereby adjusting a film thickness of the resin E on the surface of the resin-impregnated roll R.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for producing a prepreg.

  A fiber reinforced composite material in which a reinforced fiber is combined with a resin is used in various applications because it is excellent in lightness, rigidity, impact resistance, and the like.

  As a method for producing a fiber reinforced composite material, a method of curing a prepreg obtained by impregnating a reinforcing fiber with a thermosetting resin such as an epoxy resin is known. For example, this prepreg is obtained by impregnating a fiber base material with a resin-impregnated roll impregnated with a resin while drying the resin-impregnated base material while conveying a long fiber base material in the longitudinal direction. Manufactured.

  By the way, when manufacturing the prepreg, the amount of resin impregnated into the fiber base material is one of important manufacturing parameters, and in Patent Document 1 below, the amount of resin is controlled as follows. Specifically, the film thickness of the resin on the surface of the resin-impregnated roll impregnated with the resin is adjusted by a film thickness adjusting plate (blade) according to the conveying speed of the fiber base material. Thereby, even if the moving speed of the fiber base material fluctuates, the amount of resin impregnated can be accurately controlled.

JP 2000-108211 A

  However, since the conventional prepreg manufacturing method described above does not consider the control of the resin amount when the width of the fiber base material (fiber bundle) changes, the fiber bundle when the width of the fiber bundle changes. There is a possibility that the amount of resin impregnated in the material changes. Since the amount of resin impregnated in the fiber bundle (in other words, the resin content of the prepreg) affects the quality of the fiber-reinforced composite material produced using the prepreg, control of the amount of resin is extremely important. It is.

  The present invention has been made in view of such problems, and the object thereof is a method for producing a prepreg that can suppress a change in the amount of resin impregnated in a fiber bundle even if the width of the fiber bundle changes. Is to provide.

  In order to solve the above-mentioned problems, a method for producing a prepreg according to the present invention is a method for producing a prepreg, in which a long fiber bundle is brought into contact with a resin-impregnated roll surface impregnated with a resin to supply the resin to the fiber bundle. In the method, the step of measuring the width of the fiber bundle before being impregnated with the resin, and the blade disposed close to the surface of the resin-impregnated roll and capable of adjusting the distance from the surface of the resin-impregnated roll were measured. Adjusting the film thickness of the resin on the surface of the resin-impregnated roll by controlling according to the width of the fiber bundle and the weight of the fiber bundle.

  According to this method, the amount of resin supplied from the surface of the resin-impregnated roll to the fiber bundle is controlled by controlling the blade in accordance with the width of the fiber bundle and the weight of the fiber bundle and adjusting the film thickness of the resin on the surface of the resin-impregnated roll. It can be controlled according to the width and weight of the fiber bundle. Specifically, for example, when the width of the fiber bundle measured at one timing is larger than the width of the fiber bundle measured at another timing, the blade is based on the width of the fiber bundle and the weight of the fiber bundle. The blade is controlled so as to reduce the distance between the surface of the resin impregnated roll. In addition, when the width of the fiber bundle measured at a certain timing is smaller than the width of the fiber bundle measured at another timing, the blade and the surface of the resin-impregnated roll based on the width of the fiber bundle and the weight of the fiber bundle The blade is controlled to increase the distance between the In this way, considering not only the width of the fiber bundle but also the weight of the fiber bundle, if the fiber bundle thickness is different even if the fiber bundle width is the same, the amount of resin supplied to the fiber bundle according to the thickness is determined. This is because they need to be different. By controlling the blade as described above and adjusting the resin film thickness on the surface of the resin-impregnated roll, even if the width of the fiber bundle changes, the change in the amount of resin impregnated in the fiber bundle can be suppressed. it can.

  ADVANTAGE OF THE INVENTION According to this invention, even if the width | variety of a fiber bundle changes, the manufacturing method of the prepreg which can suppress the change of the resin amount impregnated in a fiber bundle can be provided.

It is a flowchart which shows an example of the manufacturing process of a prepreg. It is a flowchart which shows an example of the resin impregnation process shown in FIG. It is explanatory drawing which shows the structure of the resin impregnation part periphery. It is explanatory drawing which shows the example which finely adjusted the amount of resin supplied to a fiber bundle. It is a graph which shows the result of the resin content rate at the time of manufacturing a prepreg using the manufacturing method concerning the embodiment of the present invention. It is a graph which shows the result of the resin content rate at the time of manufacturing a prepreg with the manufacturing method which concerns on a comparative example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the following description of the preferred embodiment is merely an example, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 is a flowchart showing an example of a manufacturing process of a prepreg. The prepreg produced according to the present invention can be suitably used for producing, for example, a fiber-reinforced composite material.

(Step S11)
First, a carbon fiber bundle wound around a bobbin (hereinafter also referred to as fiber bundle) is unwound using a drive roll or the like (bobbin unwinding step).

(Step S12)
Next, the unrolled carbon fiber bundle is opened through a plurality of rolls (opening rolls), and pretreatment such as heating is performed (opening and pretreatment steps such as heating).

(Step S13)
Next, the resin is supplied to the carbon fiber bundle by bringing the long carbon fiber bundle into contact with the surface of the resin-impregnated roll impregnated with the resin (resin impregnation step).

(Step S14)
Next, the carbon fiber bundle impregnated with the resin is moved by a plurality of rollers, and post-treatment such as heating is performed (post-treatment step such as heating).

(Step S15)
Finally, the carbon fiber bundle that has been post-processed by heating or the like is wound on a bobbin (winding step). In the prepreg manufacturing method of the present embodiment, at least a bobbin for unwinding the carbon fiber bundle, a unit for opening the carbon fiber bundle, a resin impregnated portion for impregnating the carbon fiber bundle with resin (details will be described later), and a resin It is preferable to use a unit for heating the impregnated carbon fiber bundle and a bobbin that winds up the produced prepreg.

  The resin impregnation step (step S13) shown in FIG. 1 will be further described. FIG. 2 is a flowchart showing an example of the resin impregnation step. FIG. 3 is an explanatory diagram for explaining the configuration around the resin-impregnated portion. The resin-impregnated portion 1 shown in FIG. 3 includes a resin-impregnated roll R on which the resin is uniformly applied, and a blade 30 that is disposed close to the surface of the resin-impregnated roll R and can adjust the distance between the surface of the resin-impregnated roll R; And a measuring device 40 for measuring the width of the unimpregnated carbon fiber bundle 10.

(Step S131)
First, the unimpregnated carbon fiber bundle 10 is brought into contact with the surface of the resin-impregnated roll R (roll) coated with the resin E with a uniform film thickness.

(Step S132)
Next, the width of the carbon fiber bundle 10 before entering the resin impregnation step is measured by the measuring device 40. For example, a laser sensor is used as the measuring device 40, but other sensors can be selected as long as the measuring device 40 has a function of measuring the width of the carbon fiber bundle.

(Step S133)
Next, the gap D between the blade 30 and the resin impregnated roll R is adjusted according to the measured values (the width of the carbon fiber bundle 10 measured by the measuring device 40 and the weight of the carbon fiber bundle 10 measured in advance), and the carbon fiber The amount of resin supplied to the bundle 10 is controlled. Specifically, as shown in FIG. 3, a signal measured by the measuring instrument 40 is transmitted to the control unit 50, and the control unit 50 drives the motor 60 based on the received signal and is connected to the motor 60. The position of the blade 30 is controlled. The blade 30 is disposed in the vicinity of the surface of the resin-impregnated roll R while being connected to the motor 60 via, for example, a ball screw 90 or the like, and can scrape off a part of the resin on the surface of the resin-impregnated roll R. Since the blade 30 is provided in this way, a part of the resin on the surface of the resin-impregnated roll R is scraped off and applied to the surface of the resin-impregnated roll R by controlling the position of the blade 30 by the control unit 50. The film thickness of the processed resin E is adjusted. That is, by adjusting the position of the blade 30 and finely adjusting the gap D, the film thickness of the resin E applied on the surface of the resin impregnated roll R changes, and the amount of resin supplied to the carbon fiber bundle 10 is adjusted. Is done.

  More specifically, the resin amount is adjusted based on the width and weight of the carbon fiber bundle as follows. 4A shows the width of the carbon fiber bundle measured at a certain timing and the film thickness of the resin impregnated in the carbon fiber bundle, and FIG. 4B shows the carbon fiber measured at another timing. The width of the bundle and the film thickness of the resin impregnated in the carbon fiber bundle are shown.

  As shown in FIGS. 4A and 4B, when the width W1 of the carbon fiber bundle 10 measured at a certain timing is larger than the width W2 of the carbon fiber bundle 10 measured at another timing. (W1> W2), the carbon fiber bundle 10 is impregnated with the film thickness T1 of the resin E impregnated in the carbon fiber bundle 10 based on the width of the carbon fiber bundle 10 and the weight of the carbon fiber bundle 10 measured in advance. The gap D is adjusted so as to be smaller than the film thickness T2 of the resin E (T1 <T2). That is, when the width of the carbon fiber bundle 10 is changed from W2 to W1, the control unit 50 adjusts the blade 30 so as to narrow the gap D (in consideration of the weight of the carbon fiber bundle 10). When the width of the bundle 10 changes from W1 to W2, the control unit 50 adjusts the blade 30 to widen the gap D (in consideration of the weight of the carbon fiber bundle 10). Thus, the resin supply ratio can be kept constant by controlling the blade 30 by the controller 50 based on the width and weight of the carbon fiber bundle 10.

  In the resin impregnation step described above, when the volume of the carbon fiber bundle 10 is constant, instead of controlling the blade 30 based on the width and weight of the carbon fiber bundle 10, the width of the carbon fiber bundle 10 is set. Based on this, the gap D may be adjusted by controlling the blade 30.

In the resin impregnation step described above, in order to improve the accuracy of the gap D, it is preferable that the resin impregnation roll R and the blade 30 shown in FIG. Preferably, it is preferable to prepare a resin-impregnated roll R and the blade 30 with the material in the range of thermal expansion coefficient of ^{0.5 × 10 -6 /K~5.0×10 -6 / K} .

  In the resin impregnation step described above, in order to improve the gap D accuracy, it is preferable that the temperature of the resin E, the temperature of the resin impregnation roll R, and the temperature of the blade 30 are all maintained at predetermined temperatures, for example, 40 It is preferable that the temperature is maintained within a range of ± 3 ° C.

Then, the resin amount of the prepreg manufactured by the manufacturing process of the prepreg demonstrated with reference to FIGS. 1-4 was measured. FIG. 5 is a graph showing the results of the resin content impregnated in the prepared prepreg. In this measurement, a prepreg was manufactured under the following conditions. Specifically, an epoxy thermosetting resin was used as the resin E to be impregnated. Free cutting invar (thermal expansion coefficient 1.0 × 10 ⁻⁶ / K) was used for the resin impregnated roll R and the blade 30. The resin impregnation part (resin impregnation roll R and blade 30) was heated and maintained at about 40 ° C. The gap D between the resin impregnated roll R and the blade 30 was 40 μm. After heating the resin impregnated roll R and the blade 30 to about 40 ° C., the fiber impregnating roll R, the blade 30 and the carbon fiber bundle 10 are conveyed at a speed of 200 m / min and a constant tension (20 N). Impregnation and winding were performed while finely adjusting the gap D between the two according to the value measured by the measuring device 40. A prepreg was cut 20 m every 100 m from the wound first bobbin, and the amount of resin was measured. The resin amount of the second bobbin was measured in the same manner.

  In addition, the graph G1 of FIG. 5 shows the result of having cut out the prepreg 20m for every 100m from the bobbin wound up to the 1st, and measuring the resin content rate. Graph G2 in FIG. 5 shows the result of measuring the resin content by cutting 20 m of the prepreg every 100 m from the second bobbin wound up. The horizontal axis in FIG. 5 indicates the length of the prepared prepreg (the length from winding start to winding end (fiber total length 2500 m)), and the vertical axis in FIG. 5 indicates the resin content. The difference between the resin content M1 and the resin content M2 shown in FIG. 5 is about 3.0 wt%.

  As shown in the graphs G1 (first bobbin) and G2 (second bobbin) in FIG. 5, the prepregs manufactured according to the present invention are both stably within the target range (average) from the first winding to the last winding. The fluctuation range from the value is within ± 0.5 wt%). This indicates that a substantially constant resin supply ratio is maintained over the entire length of the manufactured prepreg. Further, as shown in FIG. 5, it was confirmed that the graphs G1 and G2 were compared and there was no significant difference in the resin content, that is, there was no significant change in the resin content even when the bobbin was changed. Further, it was confirmed that there was no long-term upward or downward tendency from the beginning of winding to the end of winding, and that stable production was possible.

For comparison, FIGS. 6A to 6C show the results when a prepreg is produced by a conventional method. FIG. 6A is a graph showing the resin content when a prepreg is manufactured in the same manner as in the above-described embodiment except that the position of the blade 30 is not adjusted. FIG. 6B is the same as the above-described embodiment except that an Al alloy (thermal expansion coefficient 23 × 10 ⁻⁶ / K) is used for the resin-impregnated roll R and the blade 30 and the position of the blade 30 is not adjusted. It is a graph which shows the resin content rate at the time of producing a prepreg. FIG. 6C shows a prepreg as in the above-described embodiment except that stainless steel (coefficient of thermal expansion: 16 × 10 ⁻⁶ / K) is used for the resin-impregnated roll R and the blade 30 and the position of the blade 30 is not adjusted. It is a graph which shows the resin content rate at the time of producing.

  In addition, the horizontal axis of FIG. 6 (A)-(C) shows the length (length from winding start to winding completion (fiber total length 2500m)) of the produced prepreg. The vertical axis | shaft of FIG. 6 (A)-(C) shows resin content rate. The difference between the resin content M1 and the resin content M2 shown in FIGS. 6A to 6C is about 3.0 wt%, as in FIG.

  In the result of the resin content shown in FIG. 6A, the resin amount is within the target range (the fluctuation range of the resin content is about 3.0 wt% or less), but the resin content varies widely. Moreover, when the 1st bobbin (graph H1) and the 2nd bobbin (graph H2) are compared, the difference with the resin content is large. This indicates that the stability of the amount of resin supplied to the carbon fiber bundle cannot be secured when the width of the carbon fiber bundle changes due to the change of the bobbin.

  From the result of the resin content shown in FIG. 6B, the resin amount is within the target range (the fluctuation range of the resin content is about 3.0 wt% or less), but the dotted line arrow in FIG. As shown, it can be confirmed that the resin content decreases as the winding length increases. When the resin content fluctuates in this way, the possibility that the amount of the resin falls outside the target range is very high, and stability may not be ensured when continuous production is performed.

  From the result of the resin content shown in FIG. 6C, the resin amount is within the target range (the fluctuation range of the resin content is about 3.0 wt% or less), but the dotted line arrow in FIG. As shown, the resin content is greatly reduced at the beginning of winding (down about 2.0 wt% from the beginning of winding). If the resin content fluctuates in this way, even if the initial resin content is within the target range, it is very likely that the resin amount will be out of the target range at the end of the long-distance winding. It may not be possible to stabilize the production.

  In the embodiment described above, in the method for producing a prepreg, the resin E is supplied to the carbon fiber bundle 10 by bringing the long carbon fiber bundle 10 into contact with the surface of the resin impregnated roll R impregnated with the resin E. A step of measuring the width of the carbon fiber bundle 10 before being impregnated with E, and a blade 30 which is arranged close to the surface of the resin-impregnated roll R impregnated with the resin E and can adjust the distance from the surface of the resin-impregnated roll R. Adjusting the film thickness of the resin E on the surface of the resin-impregnated roll R by controlling according to the width of the carbon fiber bundle 10 measured by the measuring device 40 and the weight of the carbon fiber bundle 10 measured in advance; Is provided.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed.

10: Carbon fiber bundle (fiber bundle)
30: Blade 40: Measuring instrument 50: Control unit 60: Motor D: Gap E: Resin R: Resin impregnated roll

Claims (1)

In the method for producing a prepreg, the resin is impregnated with a resin-impregnated roll, and a long fiber bundle is brought into contact with the surface to supply the resin to the fiber bundle.
Measuring the width of the fiber bundle before being impregnated with the resin;
The resin-impregnated roll is controlled by controlling a blade disposed close to the surface of the resin-impregnated roll and capable of adjusting a distance from the surface of the resin-impregnated roll according to the measured width of the fiber bundle and the weight of the fiber bundle. And a step of adjusting the film thickness of the resin on the surface.

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