JP2002241051A - Carbon fiber bundle reeling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon fiber bundle reeling method capable of reducing any breakage or shag caused when reeling carbon fiber bundle from a winding bobbin. SOLUTION: When reeling the carbon fiber bundle Y from the winding bobbin 1 with the carbon fiber bundle Y treated by sizing agent mainly consisting of uncured thermosetting resin wound therearound and feeding it to a next step, the carbon fiber bundle is reeled while heating the winding bobbin 1, or reeled while maintaining a heat-insulated condition by the pre-heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for unwinding a carbon fiber bundle, and more particularly to a method for unwinding a carbon fiber bundle from a winding bobbin wound with a carbon fiber bundle treated with a sizing agent. The present invention relates to an unwinding method capable of reducing cutting and fuzz.

[0002]

2. Description of the Related Art Carbon fiber is a fiber reinforced resin (CFRP).
It is widely used as a reinforcing material when forming or manufacturing a composite material such as. In general, when a carbon fiber bundle is wound on a winding bobbin in a manufacturing process, in order to improve interfacial adhesion between a fiber reinforced resin and a matrix resin, or to improve convergence, the carbon fiber bundle is surface-treated with a sizing agent beforehand. It has been wound up.

[0003] The sizing agent is mainly composed of an uncured thermosetting resin having a relatively low molecular weight such as an epoxy resin. However, since the sizing agent has tackiness at room temperature, the carbon fiber bundle is wound around a bobbin. If the carbon fiber bundle is unwound, a bonding phenomenon occurs between the wound yarn layers, and a high peeling resistance occurs when the carbon fiber bundle is unwound. On the other hand, the carbon fiber bundle has a characteristic that it is brittle and easily broken because the elongation at break is almost zero in the state of the bare yarn before being compounded.

[0004] Therefore, if the carbon fiber bundle is subjected to a large peeling resistance when unwound from the winding bobbin, a strong bending and tensile load is applied, so that there is a problem that yarn breakage or fuzzing is likely to occur. If yarn breaks occur during production, the production process must be interrupted, which lowers the operating rate, and inferior yarn breaks cause quality deterioration. In addition, fluffing similarly causes quality deterioration.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for unwinding a carbon fiber bundle which can reduce yarn breakage and fluffing when unwinding from a winding bobbin.

[0006]

According to the present invention, there is provided a method for unwinding a carbon fiber bundle comprising: a winding bobbin wound from a carbon fiber bundle treated with a sizing agent containing an uncured thermosetting resin as a main component;
When the carbon fiber bundle is unwound and supplied to a higher-order process, the winding bobbin is unwound while being heated, or unwound while maintaining a heat retaining state by preheating. is there.

As described above, when the carbon fiber bundle is unwound from the winding bobbin, the sizing agent for the uncured thermosetting resin can be reduced by heating the winding bobbin or maintaining it in a pre-heated state. Let it soften. Therefore, the peeling resistance between the carbon fiber bundles when the carbon fiber bundles are unwound is reduced, the occurrence of yarn breakage and fluffing is reduced, and operability and quality can be improved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the sizing agent used for the surface treatment of a carbon fiber bundle is not particularly limited as long as it is mainly composed of an uncured thermosetting resin. For example, epoxy resin, unsaturated polyester resin, vinyl ester resin and the like can be exemplified.

In the present invention, the heating of the winding bobbins performed when the carbon fiber bundles are unwound may be performed by heating the winding bobbins individually one by one, or collectively in units of a plurality of winding bobbins. May be heated. Due to the heat treatment of the bobbin, the sizing agent, which had been surface-treated on the carbon fiber bundle, is in a softened state. Can be reduced. In such a heating treatment, the winding bobbin may be heated in advance before being subjected to the unwinding step, and unwound while maintaining the heat retaining state obtained by the preheating.

[0010] The heating temperature in the above-mentioned heat treatment or the heat retention temperature after preheating is preferably in the range of 40 to 90 ° C. When the temperature is lower than 40 ° C., the softening of the sizing agent becomes insufficient, and the effect of preventing yarn breakage decreases. Also, 9
If the temperature is higher than 0 ° C., the effect of preventing yarn breakage is sufficient, but since the effect is saturated, there is a disadvantage that heating energy is consumed extra. Further, since the curing reaction of the sizing agent is caused, the compatibility with the matrix resin is inhibited, and a disadvantage that the interfacial adhesion is reduced also occurs.

In the present invention, as long as it is a step of unwinding a carbon fiber bundle, an application step for use is not particularly limited. For example,
Weaving preparation process such as warping process, weaving process, prepreg manufacturing process, filament winding process, dipping (impregnation) process, pultrusion (drawing) process, roping extrusion (extrusion) process, chopped fiber cutting process and the like are exemplified. be able to.

FIG. 1 illustrates a case where the present invention is applied to a warping step of a carbon fiber bundle.

In FIG. 1, reference numeral 1 denotes a winding bobbin on which a carbon fiber bundle Y surface-treated with a sizing agent is wound, and a number of winding bobbins 1 are suspended on a creel stand 2 in multiple rows and multiple stages. . As the sizing agent, those mainly composed of an uncured thermosetting resin such as an epoxy resin are used. Numeral 3 denotes a warping drum. When the warping drum 3 is rotationally driven, the carbon fiber bundles Y are unwound from a large number of winding bobbins 1, respectively. And wound up on the warping drum 3.

A plurality of winding bobbins 1 suspended in a creel stand 2 in multiple rows and multiple stages are housed in a closed space 4 surrounded by a transparent resin sheet 4a. An exhaust port 5 and a supply port 6 are provided in the upper and lower portions of the closed space 4, and a duct 7 connecting a blower 8 and a heater 9 is connected between them. In the operating state, the blower 8 and the heater 9
The blower 8 sucks the air in the closed space 4 from the discharge port 5 to the duct 7, and the heater 9 heats the air to supply the air from the supply port 6 to the closed space 4 again. By repeating the circulation of the heated air in this manner, a large number of winding bobbins 1 in the closed space 4 are heated.

As described above, when the carbon fiber bundle Y is unwound from the multiple bobbins 1 and wound up on the warping drum 2 while the winding bobbin 1 is being heated, the carbon fiber bundle Y is unwound. The sizing agent on the impregnated surface softens, and due to the softening, the adhesive force between the carbon fiber bundles Y on the winding bobbin 1 decreases, and the carbon fiber bundles Y can be easily peeled off even with a small unwinding tension. Therefore, the carbon fiber bundle Y is unwound without applying an excessive bending load. Therefore, the operability can be improved and the quality can be improved without causing yarn breakage or fluffing.

FIG. 2 illustrates a case where the present invention is applied to a winding bobbin for weft in a weaving process of carbon fiber.

Only one winding bobbin 1 for the weft is accommodated in the closed space 4, and each time the weft is inserted, a carbon fiber bundle Y having a fixed length is provided.
Is unwound from the winding bobbin 1. Heated air is supplied to the closed space 4 from the supply port 6 and exhausted from the exhaust port 6, so that the internal winding bobbin 1 is constantly heated.

Also in the case of the embodiment shown in FIG. 2, the carbon fiber bundle Y
Since the sizing agent on the surface is softened by heating, the peel resistance when unwound from the bobbin 1 is reduced, and the sizing agent is unwound with a small unwinding tension without receiving excessive bending or tensile load. . Therefore, the operability is improved without causing yarn breakage and fluff, and the quality is improved.

[0019]

EXAMPLE A plurality of winding bobbins wound with carbon fiber bundles (elastic modulus 230 GPa, tensile strength 3,530 MPa) surface-treated with a sizing agent mainly composed of epoxy resin were used at an unwinding speed of 120 m / min. When performing warping while winding the yarn on a warping drum while unwinding, the apparatus shown in FIG. 1 is used to supply heated air at 70 ° C. to a closed space to heat the bobbin (Example). The number of occurrences of yarn breakage during the process was examined between the case where the air was not supplied and the room temperature was 20 ° C. (comparative example).

As a result, in the example of the present invention, no yarn break occurred at all, but in the method of the comparative example, 40 times / l was used.
0 ⁵ yarn breakage of m occurred.

[0021]

As described above, according to the present invention, when unwinding a carbon fiber bundle, the sizing agent is softened because the bobbin is heated or preheated to keep it warm. As a result, the separation resistance between the carbon fiber bundles is reduced, and the carbon fiber bundles can be easily unwound without applying an excessive bending load. Therefore, yarn breakage at the time of unwinding does not occur, and generation of fluff can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a warping process for implementing the present invention.

FIG. 2 is a schematic diagram showing a part of a winding bobbin for a weft in a weaving process for carrying out the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Winding bobbin 2 Creel stand 3 Warping drum 4 Closed space 5 Exhaust port 6 Supply port 7 Duct 8 Blower 9 Heater F Carbon fiber bundle

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3B154 AA14 AB09 BA55 BB12 BB47 BE01 BF01 DA21 4L033 AA09 AB01 AC12 CA49 4L036 MA04 PA18 UA21

Claims (3)

[Claims] When unwinding a carbon fiber bundle from a winding bobbin wound with a carbon fiber bundle treated with a sizing agent containing an uncured thermosetting resin as a main component and supplying it to a higher process, ,
A method of unwinding a carbon fiber bundle in which the winding bobbin is unwound while being heated or unwound while maintaining a warm state by preheating. 2. The method of unwinding a carbon fiber bundle according to claim 1, wherein the winding bobbin is accommodated in a closed space, and a heating gas is supplied to the closed space to heat the winding bobbin strip. 3. The method of unwinding a carbon fiber bundle according to claim 1, wherein a heating temperature of the winding bobbin or a heat retaining temperature after preheating is set to 40 to 90 ° C.