JP2009191238A - Method for producing carbon fiber-reinforced resin molded material and carbon fiber-reinforced resin molded material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for producing a carbon fiber-reinforced resin molded material excellent in external appearance in a simple and inexpensive way. <P>SOLUTION: The method for producing the carbon fiber-reinforced resin molded material 10 composed of an opened carbon fiber (tow) 11 and a resin 12 comprises: a cutting step of cutting the carbon fiber 11; a dropping step of dropping the cut carbon fiber 11 to the resin 12; an orientation step of orienting the carbon fiber 11 stuck into the resin 12 to a predetermined direction; and an impregnation step of impregnating the oriented carbon fiber 11 with the resin 12. Since the carbon fiber 11 stuck into the resin 12 is oriented to the predetermined direction, the carbon fiber 11 can be prevented from being broken. The external appearance of a product can be kept excellent if the carbon fiber 11 is not broken. Consequently, the carbon fiber-reinforced resin molded material 10 excellent in external appearance can be obtained in a simple and inexpensive way. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for producing a carbon fiber reinforced resin molding material comprising a carbon fiber that has been opened and a resin.

For the purpose of reducing the weight of the vehicle body, a carbon fiber reinforced resin molding material obtained by impregnating carbon fiber with a resin is used for an outer panel of the vehicle body.
Such a carbon fiber reinforced resin molding material is manufactured by an apparatus as shown in the following figure.

  FIG. 4 is a diagram for explaining a conventional method for producing a carbon fiber reinforced resin molding material. A carbon fiber reinforced resin molding material production apparatus 100 shown in FIG. 4A is a sheet-like carbon fiber 101 that has been pre-opened. A carbon fiber supply roller 102, a cutting machine 103 for cutting and dropping the supplied carbon fiber 101 into a predetermined length, a lower belt conveyor 104, and a lower film 104F on the lower belt conveyor 104. Impregnated with the lower resin 107, the carbon fiber 108 dropped on the lower resin 107, the upper resin 111 supplied by the upper film 109F on the upper belt conveyor 109 and supplied to overlap the lower resin 107. It comprises an impregnation roller 112 that pressurizes the upper resin 111 toward the lower resin 107 for urging.

  The cut carbon fiber 108 is dropped on the lower resin 107, and the upper resin 111 is overlaid thereon and compressed by the impregnation roller 112, whereby the carbon fiber reinforced resin molding material 120 in which the carbon fiber is impregnated with the resin. Is manufactured.

  By the way, as shown in (b) which is an enlarged view of part b in (a), the carbon fiber 108 is left to fall freely in front of the impregnation roller 112. The carbon fibers 108b in a standing shape or the carbon fibers 108a, 108d, 108g in a shape inclined to the right in the figure are dispersed in the lower resin 107. Since these are strongly compressed by the impregnation roller 112 through the upper resin 111, the carbon fibers 108e and 108f may be bent in a U shape between the upper and lower belt conveyors 109 and 104.

FIG. 5 is a diagram for explaining a conventional carbon fiber reinforced resin molding material. As shown in FIG. 5A, part of the folded carbon fibers 108h, 108i, 108j (108h, 108k) has a vertical fiber orientation. The shrinkage is different due to the difference from the others. Due to the different shrinkage rates, the upper resin 111 is pushed up to form the convex portion 122.
When the convex part 122 appears on the surface of the carbon fiber reinforced resin molding material 120 as shown in (b), the appearance of the carbon fiber reinforced resin molding material 120 is damaged. Therefore, measures to improve the appearance are required.

Conventionally, a carbon fiber reinforced sheet-shaped molding material is known as a technique for improving the appearance (see, for example, Patent Document 1).
JP 2001-348440 A (first page)

  The first page of Patent Document 1 [Claim 1] states, “In a sheet-shaped molding material in which short fibers made of carbon fibers are dispersed in a thermosetting resin, a nonwoven fabric made of carbon fibers is arranged near the surface. The carbon fiber reinforced sheet-shaped molding material characterized by the above. "

That is, the appearance is improved by covering the surface of the carbon fiber reinforced resin molding material 120 as shown in FIG. 5B with a nonwoven fabric.
Although the appearance is good, on the other hand, the procurement cost of the nonwoven fabric and the trouble of covering the surface of the carbon fiber reinforced resin molding material 120 with the nonwoven fabric are increased, and the manufacturing cost increases.

  Therefore, there is a demand for a technique for producing a carbon fiber reinforced resin molding material that is simple, low-cost, and has good appearance.

  An object of the present invention is to provide a technique for producing a carbon fiber reinforced resin molding material that is simple, low-cost, and has good appearance.

The invention according to claim 1 is a method for producing a carbon fiber reinforced resin molding material comprising a carbon fiber that has been opened and a resin.
A cutting step of cutting the carbon fiber;
A dropping step of dropping the cut carbon fiber onto the resin;
An alignment step of orienting the carbon fibers stuck in the resin in a predetermined direction;
An impregnation step of impregnating the oriented carbon fiber with the resin.

  The invention according to claim 2 is manufactured by the method for manufacturing a carbon fiber reinforced resin molding material according to claim 1.

In the invention according to claim 1, the carbon fibers stuck in the resin are oriented in a predetermined direction. By orienting the carbon fibers in a predetermined direction, the carbon fibers can be prevented from being broken.
The orientation of the carbon fibers can be easily performed by means such as providing a guide member in the carbon fiber reinforced resin molding material production apparatus.

  In addition, since the carbon fiber is prevented from being bent, it is not necessary to cover the carbon fiber reinforced resin molding material with a nonwoven fabric or the like. As a result, it is possible to produce a carbon fiber reinforced resin molding material with good appearance at low cost.

  In the invention which concerns on Claim 2, the surface is smooth and the carbon fiber reinforced resin molding material with a favorable external appearance is provided.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a diagram for explaining a carbon fiber reinforced resin molding material according to the present invention. A carbon fiber reinforced resin molding material 10 includes an opened carbon fiber 11 and an unsaturated polyester for impregnating the carbon fiber 11. And the like.
An apparatus for producing such a carbon fiber reinforced resin molding material 10 will be described with reference to the following drawing.

  FIG. 2 is a diagram for explaining a carbon fiber reinforced resin molding material manufacturing apparatus according to the present invention. The carbon fiber reinforced resin molding material manufacturing apparatus 20 supplies carbon that supplies sheet-like carbon fibers 21 that have been pre-opened. A fiber supply roller 22, a cutting machine 23 for cutting the supplied carbon fiber 21 into a predetermined length and dropping it, a lower belt conveyor 24, and a lower resin 27 placed on a lower film 24F on the lower belt conveyor 24. The carbon fiber 11 that is lowered on the lower resin 27, the guide member 29 for orienting the carbon fiber 11 in a predetermined direction, and the upper film 31F on the upper belt conveyor 31 are supplied to the lower resin 27. The upper resin 33 is supplied so as to overlap, and the impregnation roller 34 pressurizes the upper resin 33 toward the lower resin 27 in order to promote the impregnation.

  As shown in the figure, the guide member 29 is provided in the vicinity of the impregnation roller 34 and at a position closer to the cutting machine 23 than the impregnation roller 34.

  The cut carbon fiber 11 is dropped on the lower resin 27, and the upper resin 33 is overlaid thereon and compressed by the impregnation roller 34, whereby the carbon fiber reinforced resin molding material 10 in which the carbon fiber is impregnated with the resin. Is manufactured.

The resin is composed of an upper resin 33 and a lower resin 27, and the upper and lower resins 33 and 27 are integrally formed by being pressurized and impregnated by the impregnation roller 34.
Therefore, when the carbon fiber reinforced resin molding material 10 is molded, the upper resin 33 and the lower resin 27 cannot be distinguished.

A wire can be used for the guide member 29. The wire is inexpensive and strong, and can be easily attached to the carbon fiber reinforced resin molding material manufacturing apparatus 20.
The guide member 29 may be a jig other than a thread, string, or rod. That is, it is not limited to these as long as the carbon fibers can be oriented in a predetermined direction.
The operation of the guide member will be described with reference to the next figure.

  FIG. 3 is a view for explaining the operation of the guide member according to the present invention. As shown in FIG. 3A, the lower resin 27 and the carbon fiber 11 are integrally moved in the direction indicated by the arrow (1). .

The carbon fiber 11 protruding above the lower surface portion 37 of the guide member 29 is fixed to the fixed guide member 29 by the force that the lower resin 27 moves to the right in the drawing as shown in FIG. It is brought down to the position of the lower surface portion 37 so as to come into sliding contact.
That is, it can be said that the carbon fibers 11 are oriented in a predetermined direction.

  The carbon fiber 11 tilted by the guide member 29 is moved to a position where the impregnation roller 34 is disposed, as shown in (c). The carbon fiber 11 is brought down to a position lower than the lower surface portion 37 by the guide member 29. The lower surface portion 37 is disposed at a position lower than the lower end portion 38 of the impregnation roller indicated by an imaginary line. There is no fear that the carbon fiber 11 is broken by the pressure of the impregnation roller 34.

The carbon fiber 11, the lower resin 27, and the upper resin 33 are impregnated by the impregnation roller 34, and further pressurized by the pressure roller 39 as shown in FIG.
Thus, the carbon fiber reinforced resin molding material 10 shown in FIG. 1 is obtained.

  Next, the reliability of the invention is confirmed by experiments. Experiments were performed by changing the opening and non-opening of the carbon fiber and changing the presence or absence of the step of orientation in a predetermined direction.

(Experimental example)
Experimental examples according to the present invention will be described below. Note that the present invention is not limited to experimental examples.

○ Summary of experiment:
In an Example, an impregnation body is obtained by (1) opening process and (2) impregnation process. The impregnated body is subjected to a curing treatment by (3) a thermal curing step, and (4) a surface roughness measurement step is performed on the obtained cured product.
In the comparative example, (1) fiber opening step, (2) impregnation step, (3) thermal curing step, and (4) surface roughness measurement step are carried out. Different.

○ Opening process:
Carbon fiber: HTA-12K-E30 manufactured by Toho Tenax
-Opening treatment: The carbon fibers were opened by air pressure under the conditions of a supply air pressure of 0.5 MPa, an air blowing diameter of 50 mm, and a fiber traveling speed of 1 m / min.

○ Impregnation process:
・ Impregnated resin material:
Highly reactive polyester: 100 parts by weight Calcium carbonate: 180 parts by weight Vinyl acetate elastomer: 6 parts by weight Curing agent: 1 part by weight Thickener: 1 part by weight

-Example impregnation machine: SMC production equipment manufactured by Tsukishima Kikai, but in the form of FIG. That is, there is a guide member for orientation.
Comparative impregnating machine: SMC manufacturing equipment manufactured by Tsukishima Kikai, but in the form of FIG. That is, there is no guide member for orientation.

○ Thermal curing process:
-Molding machine: 200 ton press made by Kawasaki Yoko Co., Ltd.-Thermal curing: A carbon fiber reinforced resin molding material (impregnated body) cut into 160 mm x 160 mm is put into a mold having a cavity size of 300 mm x 300 mm. Then, the carbon fiber reinforced resin molding material (impregnated body) placed on the mold center is subjected to a curing process under conditions of a mold temperature of 140 ° C., a mold clamping time of 4 minutes, and a mold clamping pressure of 10 MPa.

○ Surface roughness measurement process:
・ Roughness measuring instrument: Mitutoyo SV300CNC
・ Measurement range: 50mm
Measurement item: Maximum height roughness Rz (maximum height roughness specified in JIS B0601)

  The results of the above experiment are shown in Table 1.

  When Ra ≦ 5 μm was accepted as the criterion in the column for the evaluation of the surface roughness Rz and Ra> 5 μm was rejected, the example in which the carbon fibers were oriented in a predetermined direction passed 4.5 μm. On the other hand, in the comparative example in which the carbon fibers were not oriented in the predetermined direction, it was rejected at 9.3 μm.

As this cause, it is considered that the carbon fiber protrudes from the lower resin. Therefore, the number of standing carbon fibers was measured. The number of standing carbon fibers is shown in the reference column. The standing number L of carbon fibers was defined as the number of carbon fibers per unit area (1 m ² ) standing immediately before impregnation with the impregnation rollers (impregnation rollers 34 and 112 in FIGS. 2 and 4). That is, the standing number L of carbon fibers is represented by L (lines / m ² ).

In the example, since the carbon fiber is oriented in a predetermined direction by the guide member, the carbon fiber standing is 0 (lines / m ² ) and the carbon fiber is not broken. Since the carbon fiber does not bend, unevenness due to the spring action of the carbon fiber does not occur on the surface of the cured product, and it is considered that the surface roughness Rz is reduced.

On the other hand, in the comparative example, the carbon fiber standing L was 23 (lines / m ² ). These carbon fibers are folded on the impregnation roller in the impregnation step. It is considered that unevenness is formed on the surface of the cured product by the spring action of some of the carbon fibers folded by the impregnation roller.

  That is, in the embodiment according to the present invention, the carbon fiber can be prevented from being bent by orienting the carbon fiber in a predetermined direction. The orientation of the carbon fibers can be easily performed by means such as providing a guide member in the carbon fiber reinforced resin molding material production apparatus. By preventing the breakage, it can be said that a carbon fiber reinforced resin molding material having a smooth surface and a good appearance can be provided easily and at low cost.

  In addition, the carbon fiber reinforced resin molding material of the present invention can be used for a motorcycle, a boat, an airplane, and the like in addition to a vehicle outer panel, and its application is not limited.

  The carbon fiber reinforced resin molding material of the present invention is suitable for a vehicle outer panel.

It is a figure explaining the carbon fiber reinforced resin molding material which concerns on this invention. It is a figure explaining the manufacturing apparatus of the carbon fiber reinforced resin molding material which concerns on this invention. It is a figure explaining the effect | action of the guide member which concerns on this invention. It is a figure explaining the manufacturing method of the conventional carbon fiber reinforced resin molding material. It is a figure explaining the conventional carbon fiber reinforced resin molding material.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Carbon fiber reinforced resin molding material, 11 ... Carbon fiber, 12 ... Resin, 20 ... Carbon fiber reinforced resin molding material manufacturing apparatus, 21 ... Sheet-like carbon fiber, 23 ... Cutting machine, 29 ... Guide member, 34 ... Impregnation roller.

Claims (2)

In the method for producing a carbon fiber reinforced resin molding material comprising a carbon fiber that has been opened and a resin,
A cutting step of cutting the carbon fiber;
A dropping step of dropping the cut carbon fiber onto the resin;
An alignment step of aligning the carbon fibers dropped on the resin in a predetermined direction;
An impregnation step of impregnating the oriented carbon fibers with the resin, and a method for producing a carbon fiber reinforced resin molding material.   A carbon fiber reinforced resin molding material produced by the method for producing a carbon fiber reinforced resin molding material according to claim 1.

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