JPH059861A - Carbon fiber manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to efficiently and simultaneously produce carbon fibers to which a sizing agent having various properties is added, while minimizing the time and economic loss, and particularly Variety,
Provided is a method for producing carbon fiber suitable for small-quantity production. [Structure] Carbon fibers F are sorted by a yarn distributing device 2, and a predetermined number of carbon fibers F are supplied to each sizing agent applying device 1A, 1B, 1C. Each size application device 1A, 1B,
The properties of the sizing agents S (S _A , S _B , S _C ) contained in 1C are different, that is, the types and concentrations of sizing agents are different.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally produces carbon fibers (in the present specification, "carbon fibers" include not only carbon fibers but also graphite fibers unless otherwise specified). In particular, the present invention relates to a technique, and in particular, a method for producing a carbon fiber characterized in that a plurality of types of carbon fibers to which a sizing agent having different properties are added are produced simultaneously by continuously threading a large number of yarns. It is about.

[0002]

2. Description of the Related Art Recently, not only PAN-based and pitch-based carbon fibers but also carbon fibers produced by using other raw materials as precursors have been widely used as reinforcing fibers for carbon fiber-reinforced composite materials in the fields of automobiles, aircraft, and other industries. It is used.

One of the most important factors in producing such a carbon fiber reinforced composite material is to improve the adhesion between the matrix resin and the carbon fiber, and further to improve the yarn handling property of the carbon fiber. is there.

In order to improve the adhesiveness between the matrix resin and the carbon fiber, a measure has been taken to improve the adhesiveness with the matrix resin by imparting a functional group to the surface of the carbon fiber by, for example, electrolytic oxidation. On the other hand, the carbon fiber thus surface-treated by electrolytic oxidation or the like for improving the adhesiveness has a high strength but is rigid and poor in bending resistance and scratch resistance, and therefore, from the bobbin in the manufacturing process or the high-order processing process. Fluffing is likely to occur due to contact with an unwinding roller, a yarn path guide, or rubbing or bending operation during grading, and there is a problem in yarn handling such as yarn breakage. This is a problem, and for that reason, the carbon fiber is subjected to a sizing treatment for the purpose of improving the yarn handling property.

Further, the carbon fiber produced in this manner is impregnated with a matrix by prepreg molding or filament winding molding. In order to obtain the best adhesion with the matrix resin, these molding methods are used. Accordingly, the properties of the sizing agent in the sizing treatment, that is, the type and the concentration are made different.

[0006]

Conventionally, in the case of producing carbon fibers, a large number of yarns are simultaneously and continuously passed,
A series of treatments such as infusibilization treatment and carbonization treatment are performed continuously. For sizing treatment, one bath containing one sizing agent is prepared in the threading path, and many yarns are all used in this bath. It was done by leading to.

Therefore, in the case of producing carbon fibers having different sizing properties, (1) in a series of continuous carbon fiber production steps, the winding of the carbon fibers is carried out from the product paper tube to the end. After switching to the cut paper tube, replace the sizing agent in the bathtub with a sizing agent of another property, and then switch to the product paper tube again to continue, or (2) use a specific sizing agent, After producing a specific amount exceeding the required amount of carbon fiber product, newly start threading, and perform a series of production steps using sizing agents with different properties,
Have been adopted.

However, according to the above method (1), it takes time to switch to a sizing agent having another property, and the yarn end cutting loss is large, resulting in poor production efficiency. There is a problem, and according to the method (2), it takes a long time to prepare the carbon fibers as required, and an unnecessary amount of products is produced, which is wasteful. There are problems such as cases.

Therefore, an object of the present invention is to minimize time and economical loss, and to simultaneously and efficiently produce carbon fibers provided with a sizing agent having various properties without waste. It is to provide a method for producing carbon fiber suitable for high-mix low-volume production.

[0010]

The above object can be achieved by the method for producing carbon fiber according to the present invention. In summary, the present invention provides a method for continuously producing a carbon fiber by threading a plurality of yarns, wherein a plurality of baths respectively containing sizing agents having different properties are provided during a threading process. Prepare
It is characterized in that a large number of yarns are divided as necessary, guided to a bath of a required sizing agent and subjected to a sizing treatment to simultaneously produce a plurality of types of carbon fibers to which sizing agents having different properties are added. It is a manufacturing method of carbon fiber.

[0011]

The method for producing carbon fibers according to the present invention will be described in more detail below with reference to the drawings.

Referring to FIGS. 1 and 2, there is shown an embodiment of a sizing device for carrying out the carbon fiber manufacturing method of the present invention.

According to the present invention, pitch fibers and the like are arranged parallel to each other and continuously threaded at a threading speed of, for example, 1 m / min, and infusibilized in a usual manner well known to those skilled in the art. processing,
A large number of yarns (carbon fibers) F are manufactured by performing a firing treatment or the like. The number of carbon fibers F that are continuously threaded and produced at the same time is generally 10 to 500,
The number of filaments of each carbon fiber F is 100 to 10,000
It is set to 0 and usually consists of 1000 to 50,000 filaments.

Such carbon fibers F are further subjected to a surface treatment by, for example, electrolytic oxidation treatment and further washing treatment, and then a plurality of, in the present embodiment, three sizes constituted according to the present invention. Agent application device 1 (1A, 1B, 1
C).

In this embodiment, a large number of carbon fibers F are provided with a thread dividing and thread splaying roller, which are well known to those skilled in the art, before being supplied to each sizing agent applying device 1A, 1B, 1C. The yarn distribution device 2 classifies the yarns, and a predetermined number is supplied to each sizing agent applying device 1A, 1B, 1C. In this embodiment, the sizing agent applicators 1A, 1B, and 1C have the same configuration, but the sizing agent S (S
_A , S _B , and S _C ) are different in their properties, that is, the type and concentration of the sizing agent.

The sizing agent applicators 1A, 1B and 1C are
Corresponding sizing agent _{S (S A, S B,} S C) and bath 4 to reservoir a (4 _A, 4 _B, 4 _C), leads to the carbon fiber F in the bath tank 4, a sizing agent bath tub 4 Immerse in S,
Then, it has a roller means 6 for sending it out of the bath. The roller means 6 is provided with at least one guide roller 6 provided in a state of being immersed in the sizing agent S in the bath 4.
a and guide rollers 6b, 6c arranged at the inlet and outlet of the bath 4 which are not immersed in the size S above the bath 4. Although the guide rollers 6a to 6c can be made of any material, stainless steel having a diameter of 20 to 100 mm,
It is preferably made of aluminum, graphite, carbon fiber reinforced resin, carbon fiber reinforced graphite material or the like.

The sizing agent used in the present invention includes:
Although any emulsion type can be used, an aqueous dispersion prepared by adding a surfactant to various known resins such as epoxy resin and unsaturated polyester resin is preferably used. The concentration of the sizing agent is usually in the range of 0.5 to 10% by weight, and the amount of the sizing agent attached to the carbon fiber is generally 0.2 to 5% by weight based on the weight of the carbon fiber.
The range is set to.

The carbon fiber F sized by various sizing agents by the sizing agent applying apparatus 1 having such a constitution
_A , F _B and F _C are manufactured simultaneously.

In some cases, carbon fibers that do not require sizing treatment are required. In such a case, the sizing agent S is accommodated in the sizing device 1 only for the number of carbon fibers that is not required. It is only necessary to pass the thread without passing through the size imparting device 1.

3 and 4 show another embodiment of the sizing device 1 according to the present invention.

According to this embodiment, the sizing agent applying device 1
Is equipped with one bathtub 4, and the inside of the bath is divided into three bathtubs 4 (4 _A , 4 _B , 4 _C ) by a partition plate 8, and the size agents S (S _A , S _B , S) having different properties are provided in each bath. _C ) is housed.
When the sizing agent applying device 1 having this structure is used, the yarn distributing device 2 is not necessary, and the carbon fibers F _A , F _B , and F _C sized by various sizing agents are manufactured at the same time. Further, the partition plate 8 can be installed at any position in the bathtub 4 depending on the number of carbon fibers to be treated or the type of sizing agent.

In particular, according to this embodiment, it is possible to linearly thread the carbon fiber, and the yarn distribution device 2
This is preferable because it can eliminate the damage to the yarn caused by.

5 and 6 show a further embodiment of the sizing device 1 according to the present invention.

According to this embodiment, the sizing agent applying device 1
1 has two bathtubs 4 (4 _A , 4 _B , 4 _C ) similar to the first embodiment shown in FIGS. 1 and 2, but in the present embodiment, the central bathtub 4 _B has the other two bathtubs 4 (4 _A , 4 _B , 4 _C ). The bathtubs 4 _A and 4 _C are arranged at different positions along the carbon fiber threading direction. With such a configuration, the yarn distribution device 2 is not required as in the embodiment shown in FIGS. 3 and 4, and
Further, there is an advantage that a space can be provided more than in the embodiment shown in FIG. 4 and the configuration of each sizing agent applying device 1 can be freely designed.

The sizing agents S (S _A , S _B , S _C ) having different properties are contained in the baths 4 _A , 4 _B , 4 _C , and the carbon fibers F _A , F sized by the various sizing agents.
_B and F _C are manufactured at the same time.

Of course, also in the examples of FIGS. 3 to 6, when the carbon fiber which does not require the sizing treatment is required,
Only the unnecessary number of carbon fibers may be threaded without containing the sizing agent S in the size imparting device 1, or may be passed without passing through the size imparting device 1.

[0027]

EFFECT OF THE INVENTION According to the method for producing a carbon fiber of the present invention configured as described above, a carbon fiber to which a sizing agent having various properties is added with the time and economic loss minimized is obtained. It has the feature that it can be efficiently and efficiently manufactured without waste, and is particularly suitable for high-mix low-volume production.

[Brief description of drawings]

FIG. 1 is a plan view of an example of a sizing agent applying device for carrying out the carbon fiber manufacturing method according to the present invention.

FIG. 2 is a schematic cross-sectional configuration diagram of the sizing agent applying device of FIG.

FIG. 3 is a plan view of another embodiment of the sizing agent applying device for carrying out the carbon fiber manufacturing method according to the present invention.

FIG. 4 is a schematic cross-sectional configuration diagram of the sizing agent applying device of FIG.

FIG. 5 is a plan view of still another example of the sizing agent applying apparatus for carrying out the carbon fiber manufacturing method according to the present invention.

6 is a schematic cross-sectional configuration diagram of the sizing agent applying device of FIG.

[Explanation of reference numerals] 1 sizing agent applying device 2 yarn distributing device 4 bathtub 6 roller means 8 partition plate

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display area D06M 15/70 // D06M 101: 40

Claims (1)

Claim: What is claimed is: 1. A method for producing a carbon fiber by continuously threading a large number of yarns, wherein a plurality of sizing agents having different properties are accommodated during the threading process. Prepare individual bathtubs, divide multiple yarns as needed, guide them to the bathtub of the required sizing agent, perform sizing treatment, and simultaneously use multiple types of carbon fibers with sizing agents of different properties A method for producing a carbon fiber, which comprises producing the carbon fiber.