JP2019084834A - Method for producing prepreg - Google Patents

Abstract

To provide a method for producing the molding of a prepreg excellent in quality performance.SOLUTION: There is provided a method where a laminate obtained by plurally laminating thermoplastic films 10 worked into a sheet shape and carbon fiber fabrics 20 coated with a sizing agent is made into the molding of a prepreg by a film stacking process. A plurality of holes 11 are made in each thermoplastic film 10, further, the thermoplastic films 10A, 10D are arranged at the uppermost and the lowermost of the laminate, thereafter, the upper part and the lower part are provided with release paper 30 having heat resistance in which numberless projections 31 are formed at both the upper and lower sides so as to be pressed, and, upon the pressing, a gas generated from the sizing agent is escaped from a press molding machine to the outside through the holes 11 made in the thermoplastic films 10 and the projections 31 formed in the release paper 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a prepreg manufacturing method for manufacturing a molded article of a prepreg by heating and melting a laminate in which a plurality of thermoplastic films and carbon fiber woven fabrics are alternately laminated by a film stacking method.

A manufacturing method by a film stacking method is known as a manufacturing method of a prepreg (including a so-called semipreg which suppresses a resin impregnation amount) (see, for example, Patent Document 1).
Generally, a laminate of a plurality of sheets of a thermoplastic film processed into a sheet and a carbon fiber woven fabric is heated and pressurized at a high temperature by a press molding machine and melted to produce a molded article of a prepreg.

JP 2007-138361 A

However, in general, sizing agents (of which epoxy type is often used) are applied to upper and lower surfaces of carbon fiber fabrics, so thermoplastic resins are used when producing prepreg molded articles by the film stacking method described above. If the melting temperature of the film is higher than the decomposition temperature of the sizing agent, the sizing agent is decomposed and gasified during production.
In the case of the conventional method, this gas has a risk of remaining in the space between the thermoplastic film and the carbon fiber fabric and becoming void because there is no way to escape.

  At the part where such a void is generated, there is a problem that the performance characteristics of the finished molded article of the completed prepreg deteriorate because the carbon fiber woven fabric and the thermoplastic film are not in close contact with each other.

  On the other hand, after heat and pressure treatment using a press molding machine, in order to easily release the finished prepreg molded article from the mold, release paper is laminated on both upper and lower sides of a laminate of a plurality of thermoplastic films and a carbon fiber fabric. It is known that the sizing agent sticks the decomposed gas further when the release paper is stuck.

Therefore, an object of the present invention is to provide a method for producing a molded article of prepreg excellent in quality performance.
Another object is to improve the releasability of a prepreg molded article.

In order to achieve the above object, according to the prepreg production method of the present invention, a plurality of thermoplastic films (10) processed into a sheet shape and a plurality of carbon fiber woven fabrics (20) coated with sizing agents on both upper and lower sides alternately A prepreg manufacturing method for manufacturing a molded article of a prepreg by a film stacking method in which laminated laminates are pressed by a press molding machine and heated and melted,
The thermoplastic film (10) is provided with a plurality of holes (11) penetrating vertically, and after the thermoplastic films (10A, 10D) are disposed at the top and bottom of the laminate, the press Press by molding machine,
A gas generated from the sizing agent at the time of pressing is released from the press-forming machine through the holes (11) opened in the thermoplastic film (10).

Further, in the method for producing a prepreg of the present invention, a laminate is formed by alternately laminating a plurality of thermoplastic films (10) processed into a sheet and a plurality of carbon fiber woven fabrics (20) coated with sizing agents on both upper and lower surfaces. A prepreg manufacturing method for manufacturing a molded article of a prepreg by a film stacking method in which a molding machine is pressed to heat and melt.
The thermoplastic film (10) is provided with a plurality of holes (11) penetrating vertically, and after the thermoplastic film (10A, 10D) is disposed at the top and bottom of the laminate,
Heat-resistant release paper (30) in which innumerable projections (31) are formed on both upper and lower sides of the uppermost thermoplastic film (10A) and the lowermost thermoplastic film (10D). And press with the press molding machine,
The gas generated from the sizing agent at the time of pressing is passed from the press-forming machine through between the holes (11) opened in the thermoplastic film (10) and the protrusions (31) formed in the release paper (30) It is characterized by having escaped to the outside.

  In addition, the so-called semipreg which restrained the resin impregnation amount with respect to the carbon fiber fabric (20) is also included in the prepreg as used in the present invention.

  Further, the present invention is characterized in that the protrusion (31) formed on the release paper (30) has a protrusion amount of several microns.

  In the present invention, the projections (31) formed on the release paper (30) have a contact angle (θ) with the molten resin (15) of 180 ° when the thermoplastic film (10) is melted. The protrusion amount, the space and the shape are set to an extent that they are close to each other (degree).

  The symbols in parentheses indicate corresponding elements or items described in the drawings and the modes for carrying out the invention described later.

According to the present invention, a plurality of holes are made in a thermoplastic film processed into a sheet, and gas produced from a sizing agent applied to a carbon fiber fabric when a molded article of a prepreg is manufactured by a film stacking method Is prevented from being trapped from the carbon fiber fabric and the thermoplastic film by being escaped from the press molding machine through the holes drilled in the thermoplastic film, thereby preventing the generation of voids (voids) Be done.
This makes it possible to produce a molded article of prepreg excellent in quality performance.

Further, according to the present invention, since the release paper is provided on the upper part of the uppermost thermoplastic film and the lower part of the lowermost thermoplastic film, it is completed after the heating and pressure processing by the press molding machine The molded article of the prepreg can be easily released from the mold.
At this time, since innumerable protrusions are formed on the upper and lower surfaces of the release paper, the gas generated from the sizing agent at the time of pressing is prevented from being trapped by the release paper, and the gas is released to the thermoplastic film. It escapes from the press machine through the space between the holes and the projections formed on the release paper.
Even when the release paper is provided as described above, generation of voids (voids) can be suppressed.

Moreover, according to the present invention, since the projections formed on the release paper have a protrusion amount of several microns, the resin melted from the thermoplastic film exhibits high water repellency to the release paper, so gold Easy to peel off the mold release paper. In addition, since it is also possible to prevent the molten resin from wetting the recesses between the projections, which serve as gas escape paths, the gas can be reliably escaped to the outside world.
In particular, by setting the protrusion amount, spacing and shape of the projections formed on the release paper to such an extent that the contact angle with the molten resin is close to 180 ° (degree), the molten resin is superior to the release paper. It is more preferable because it becomes to exhibit water repellency.

  As in the method for producing a prepreg according to the present invention, a plurality of holes are made in a thermoplastic film, and in addition, innumerable projections are formed on the surface of a release paper, and applied to carbon fiber fabric at the time of pressing. The fact that the gas generated from the sizing agent escapes from the press molding machine has not been known at all.

The prepreg manufacturing method which concerns on embodiment of this invention is shown, (a) is a side view, (b) is a top view. FIG. 2 shows one thermoplastic sheet in FIG. 1, (a) is a side view, and (b) is a plan view. The state which laminated | stacked the thermoplastic sheet and carbon fiber fabric of FIG. 1 alternately is shown, (a) is a side view, (b) is a top view. It is a schematic diagram which shows the molten resin which shows water repellency with respect to the release paper of FIG. The another prepreg manufacturing method which concerns on embodiment of this invention is shown, (a) is a side view, (b) is a top view.

  A method for producing a prepreg according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.

  The method for producing a prepreg according to an embodiment of the present invention comprises alternately forming a thermoplastic film (thermoplastic sheet) 10 processed into a sheet and carbon fiber woven fabrics 20 coated with sizing agents (not shown) on both upper and lower surfaces alternately. A molded article of a prepreg is manufactured by a film stacking method in which a laminated body is pressed by a press molding machine (not shown) and heated and melted. In addition, the so-called semipreg which restrained resin impregnation amount is also included in the prepreg here.

  As shown in FIGS. 2 and 3, each thermoplastic film 10A (10) has a plurality of holes (air holes) 11 penetrating vertically. Although the holes 11 are provided at equal intervals, it is not limited to this and may be random.

Here, three carbon fiber woven fabrics 20 are vertically stacked so as to be sandwiched between four perforated thermoplastic films 10A, 10B, 10C, and 10D. Therefore, the thermoplastic film 10A is disposed at the top of the laminate, and the thermoplastic film 10D is disposed at the bottom of the laminate.
In addition, since the positions of the holes 11 formed in the four thermoplastic films 10A, 10B, 10C, and 10D are the same, the holes 11 coincide with the vertical direction as shown in FIG. The positions of the holes 11 may be different for each thermoplastic film 10.

The sizing agent applied to the carbon fiber fabric 20 is used for laminating in a stable state to prevent slippage with respect to the thermoplastic film 10, and a sizing agent generally used is an epoxy-based one. Is used.
Further, the melting temperature of the thermoplastic film 10 is higher than the decomposition temperature of the sizing agent, and when the thermoplastic film 10 is melted at the time of pressing, the sizing agent is decomposed and gasified.

Next, a release paper 30 is provided on the upper portion of the uppermost thermoplastic film 10A and the lower portion of the lowermost thermoplastic film 10D.
The release paper 30 is excellent in heat resistance, and on both upper and lower surfaces, as shown in FIG. 1 and FIG. 4, innumerable protrusions 31 are formed at equal intervals. The protrusion 31 is cylindrical and has a protrusion amount T of several microns. Further, the width L in the horizontal direction of the recess 32 between the adjacent protrusions 31 is made larger than the amount T of protrusion.
And here, as shown in FIG. 4, the degree of contact angle with the molten resin 15 when the thermoplastic film 10 is melted is made close to 180 ° (degree), as shown in FIG. It is set to.

Then, after setting a laminate composed of the release paper 30, the thermoplastic film 10, and the carbon fiber fabric 20 as shown in FIG. 1 in the mold of the press molding machine, it is pressed and heated and melted.
At this time, the gas generated from the sizing agent is released from the press molding machine through the space between the holes 11 opened in the thermoplastic film 10 and the projections 31 formed in the release paper 30.
Thus, a finished product of the prepreg corresponding to the shape of the mold is formed.

  According to such a manufacturing method, a plurality of holes 11 are formed in the thermoplastic film 10 processed into a sheet, and the thermoplastic fiber 10 is applied to the carbon fiber woven fabric 20 when the molded article of the prepreg is manufactured by the film stacking method. Since the gas generated from the sizing agent escapes from the press molding machine through the holes 11 opened in the thermoplastic film 10 and is prevented from being trapped between the carbon fiber fabric 20 and the thermoplastic film 10, The occurrence of voids (air gaps) is suppressed.

Further, since the release paper 30 is respectively provided on the upper part of the uppermost thermoplastic film 10A and the lower part of the lowermost thermoplastic film 10B, the prepreg completed after heating and pressure treatment by a press molding machine Can be easily released from the mold.
At this time, since innumerable protrusions 31 are formed on the upper and lower surfaces of the release paper 30, it is avoided that the gas generated from the sizing agent at the time of pressing is trapped by the release paper 30, and the gas is a thermoplastic film 10 It is released from the press-forming machine through the space between the hole 11 and the projection 31 formed on the release paper 30.
Thus, even in the case where the release paper 30 is provided, generation of a void (void) can be suppressed.

Moreover, since the projections 31 formed on the release paper 30 have a protrusion amount of several microns, the resin 15 melted from the thermoplastic film 10 exhibits high water repellency to the release paper 30, so the mold Easy to peel off the release paper from. In addition, since it is also possible to prevent the molten resin 15 from wetting the recesses between the protrusions 31 which are to be gas escape paths, the gas can be reliably escaped to the outside world.
In particular, by setting the amount, distance, and shape of the protrusions 31 formed on the release paper 30 to such an extent that the contact angle θ with the molten resin 15 approaches 180 ° (degree), the molten resin 15 releases the release paper. It is more preferable because it exhibits super water repellency to 30.

Here, after providing the release paper 30 in which innumerable projections 31 are formed on the upper part of the uppermost thermoplastic film 10A and the lower part of the lowermost thermoplastic film 10D, after releasing, the mold release from the mold is performed. Although this has been facilitated, as shown in FIG. 5, the release paper 30 may be omitted.
According to this, although there are some difficulties in the releasability, the gas generated from the sizing agent at the time of pressing can be a thermoplastic film by using the thermoplastic film 10 in which a plurality of holes 11 penetrating vertically are formed. It is effective because it can escape to the outside through the holes 11 opened at 10 and as a result, the generation of voids can be suppressed.

10 (10A, 10B, 10C, 10D) Thermoplastic film (thermoplastic sheet)
11 hole 15 molten resin 20 carbon fiber woven fabric 30 release paper 31 protrusion 32 concave portion θ contact angle

Claims (7)

A first step of alternately laminating a sheet-like carbon fiber fabric coated with a sizing agent and a sheet-like thermoplastic film to form a laminate;
And a second step of manufacturing a prepreg by heating and pressing the laminate formed in the first step with a press molding machine,
The thermoplastic film is disposed at least on the top and bottom surfaces of the laminate,
Each of the thermoplastic films is formed with a plurality of holes penetrating the thermoplastic film in the laminating direction,
In the second step, the gas generated by the decomposition of the sizing agent when the laminate is heated and pressurized is released to the outside through the plurality of holes formed in each of the thermoplastic films, Press forming the laminate,
Prepreg manufacturing method.   The method for producing a prepreg according to claim 1, wherein the melting temperature of the thermoplastic film is higher than the decomposition temperature of the sizing agent.   The method for producing a prepreg according to claim 1 or 2, wherein positions of the plurality of holes formed in each of the thermoplastic films coincide with each other in the laminating direction of the laminate.   The prepreg manufacturing method as described in any one of Claims 1-3 arrange | positioned so that these holes may mutually be equal at intervals in the surface of the said thermoplastic film. A further release paper is placed on each of the top and bottom surfaces of the laminate,
In the second step, the laminate is press-formed while the release paper is in contact with the mold of the press-forming machine.
The prepreg manufacturing method as described in any one of Claims 1-4. A plurality of protrusions are formed on the surface of the release paper,
In the second step, a gas generated by the decomposition of the sizing agent when the laminate is heated and pressurized, the plurality of holes formed in each of the thermoplastic films, and the release paper The laminate is pressed while being released to the outside through the plurality of projections formed on the surface,
The prepreg manufacturing method of Claim 5.   The method for producing a prepreg according to claim 5 or 6, wherein the release paper has water repellency to a molten resin in which the thermoplastic film is melted.

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