JP2002115145A - Method of producing reinforcing woven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a reinforcing fiber woven fabric that can produce a carbon fiber woven fabric of high quality with the filament fibers densely and uniformly arranged by uniformly applying an amount of water enough to impart the bundling properties all over the warp yarns and inhibit the occurrence of filament damage, for example, fluffing and powdery dust. SOLUTION: Carbon fiber multifilament yarns that are treated with <=1.0% of a sizing agent and reduces the yarn width >=30% by wetting with moisture are used at least as the warp and they are woven after moisture is applied to the warp immediately before the back roll (3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a production method for weaving a reinforcing fiber woven fabric using carbon fiber multifilaments having a small amount of sizing agent and lacking bundle property as at least a warp.

[0002]

2. Description of the Related Art Conventionally, carbon fiber fabric has been used as a component of structural composite materials in all fields such as aircraft. The carbon fiber fabric is usually manufactured by weaving using a shuttle loom or a rapier loom.

However, since carbon fibers are very brittle against rubbing and bending, fluff is generated by rubbing and bending, and dust of the carbon fibers floats in the air, adheres to looms and woven fabrics, and adversely affects the human body. In addition, since there is a possibility that electrical troubles such as short circuit may occur due to conductive carbon fiber dust, a woven fabric factory of carbon fiber woven fabric is generally provided with a dust collector in the factory.

[0004] As described above, the carbon fiber fabric is formed into a composite material of a desired form using a prepreg, which is an intermediate product obtained by impregnating a matrix resin into a carbon fiber fabric, as a composite material with a resin. When molded into this composite material, the amount of the sizing agent attached to the carbon fiber multifilament is limited so as not to impair the impregnation of the matrix resin into the carbon fiber fabric. Further, as described above, since carbon fibers are brittle against bending, if twisting or air entanglement is applied to the carbon fiber multifilaments, the strength of the carbon fibers is reduced.

[0005] Therefore, carbon fiber multifilaments have poor bunching properties and are difficult to weave. To weave them without damaging the carbon fiber multifilaments,
The operating speed of the loom must be reduced, and the productivity is extremely poor. In addition, even if weaving is possible, a woven fabric obtained using carbon fibers with poor bunching properties tends to have gaps between single fibers, and obtains a woven fabric in which single fibers are uniformly and densely arranged. Can not.

Therefore, in the method of manufacturing a carbon fiber woven fabric disclosed in, for example, Japanese Patent No. 2800839, the back of a loom is controlled in order to suppress the generation of fluff and dust of carbon fibers during weaving and to improve the productivity. In the area between the roll and the weave, water is attached to the warp by a humidifier or a water spray. The amount of water attached to the warp is about 30 to 200% by weight based on the weight of the warp.

In Japanese Patent Application Laid-Open No. 5-5252, in the production of carbon fiber fabric by a rapier weaving machine, when wefts are driven between warp rows, generation of fluff due to friction and bending by a yarn path guide is prevented. For this purpose, liquid is applied to the weft. Examples of the liquid at this time include water in which polyethylene glycol is dissolved in water and methanol, and water. The liquid is applied by a method in which a weft is brought into contact with the surface of a sponge impregnated with the liquid or sprayed from the surroundings.

[0008] The method of wetting carbon fibers with water to prevent fluff and dust as disclosed in the above-mentioned publications is as follows.
It has been generally performed conventionally, and its effect has been sufficiently recognized.

[0009]

However, in any of the publications, the water is applied to the warp or weft to provide sufficient bunching properties for weaving, but the finished woven fabric is a single fiber. Are not guaranteed to be densely and uniformly arranged.

In addition, in Japanese Patent Application Laid-Open No. Hei 5-5252, water is applied only to the weft, but carbon fiber woven fabrics may use carbon fiber multifilaments only for the warp. In such a case, water is applied to the weft. Is not very effective in suppressing the fluff of the warp. In addition, the gap between the single fibers of the weft can be reduced by beating, but the gap between the single fibers in the warp still occurs.

On the other hand, in the method disclosed in Japanese Patent No. 2800839, since water is attached to the warp,
The generation of fluff and dust is sufficiently suppressed. However, since the amount of water adhered is large, the woven fabric is not sufficiently dried even when it is wound on a take-up roll after weaving, so that the woven fabric is wound with moisture. Therefore, when a process such as resin impregnation is obtained and molded into a composite material, a process of drying the carbon fiber fabric in advance may be required.

Further, in a region between the back roll and the weaving mouth of the loom, water is applied by a humidifier or a water spray. In particular, when water is applied by a water spray, water is uniformly applied to the entire warp. Is difficult to attach, and since water scatters around, there arises a problem that the machinery is corroded.

[0013] The present invention has been made to solve the above-mentioned problem, and it is possible to uniformly adhere a sufficient amount of water to the entire warp to impart convergence and suppress the generation of fluff and dust. Provided is a method for producing a carbon fiber woven fabric capable of producing a high-quality carbon fiber woven fabric in which single fibers are densely and uniformly arranged without causing yarn sway due to application of water to adversely affect the quality of the woven fabric. The purpose is. It is a further object of the present invention to provide a method for producing a dry carbon fiber fabric, which does not require drying the carbon fiber fabric in the process of producing the composite material.

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is intended to provide at least a sizing agent adhering amount of 1.0% or less as a warp and a water-wetted yarn width reduction rate of 30% or more. A method for producing a reinforcing fiber woven fabric, characterized in that weaving is performed by imparting moisture to the warp using a carbon fiber multifilament.

[0015] The term "water-wet yarn width reduction rate" used herein means:
When the reinforcing fiber is placed on the glass plate without twisting, the thread width (L), and when the reinforcing fiber is dropped on the water-free glass plate when the reinforcing fiber has been adjusted to water And the yarn width (M) after water wetting are measured, and the following formula is used to reduce the water-wet yarn width (%) = (LM) / L × 1
This is a value obtained by using 00.

In general, when the sizing agent adhesion amount is 1.0% or more and the water-wetted yarn width reduction rate is 30% or less, the sizing agent has a convergence property that does not hinder weaving even if little water is applied. However, carbon fiber multifilaments having an attached amount of the sizing agent of 1.0% or less have poor bunching properties, tend to fluff and become unstable in weaving. When the amount of adhering is 0.5% or less, it is essential to provide moisture.

In the case of weaving by adding moisture as described above, in particular, the reduction rate of the width of the wetted yarn is 30% or more. By employing such carbon fiber multifilaments, the obtained woven fabric is in a state where the single fibers of the warp are densely and uniformly arranged with each other. When the water-wetted yarn width reduction rate is 30% or less, the carbon fiber multifilament has a state in which a gap remains between the single fibers, and the resulting woven fabric also has a gap between the single fibers. The carbon fiber multifilament used in the present invention may be any of PAN-based and pitch-based carbon fibers, and is not particularly limited.

The invention according to claim 2 of the present invention includes a step of imparting moisture to the carbon fiber multifilament immediately before the back roll. By imparting water just before the back roll in this way, when the carbon fiber multifilament comes into contact with the back roll, the water is evenly impregnated between the fibers, and excess water is removed to some extent, and fluff and An appropriate minimum amount of water for suppressing generation of dust and providing convergence can be uniformly applied. Therefore, the drying time for drying the woven fabric later can be reduced.

As a method for applying water, a conventional spray method or a steam method can be employed. However, in order to apply the water uniformly over the entire warp and to control the amount of adhesion with high precision, approximately half of the warp is applied. It is preferable to employ a method in which the image is transferred by contacting the surface of the roller with water.

The invention according to claim 3 of the present invention includes a step of defining the yarn width and arrangement between the back roll and the heald while squeezing the water of the carbon fiber multifilament with a squeezing guide. By using the squeezing guide in this way, excess water can be appropriately removed, and the yarn width and arrangement can be defined while squeezing the water with the squeezing guide. A woven fabric excellent in quality can be obtained.

The invention according to claim 4 of the present invention includes a step of continuously performing a drying treatment after weaving. Since the carbon fiber woven fabric is dried continuously after weaving, it is not necessary to newly dry the reinforcing fiber woven fabric prior to the production in the subsequent prepreg manufacturing process and the like, and the woven fabric is easy to use. The drying process can be appropriately selected depending on the installation space of the apparatus, such as a suction system, a heating roll system, and a hot air system.

The invention according to claim 5 uses the carbon fiber multifilament having the number of filaments of 500 or more. In the invention according to claim 6, the fabric weight is set to 50 to 600 g / m ² . The number of filaments and the basis weight of the fabric can be appropriately changed depending on the application.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a view schematically showing a method for producing a reinforcing fiber woven fabric according to the present invention. The carbon fiber A, which is a warp, is fed out by either a creel supply method or a beam supply method, and is sent out at a predetermined speed via a supply roller 1. Thereafter, the yarn is guided to the back roll 3 while being kept at a constant tension by the low tension spring type warp tension adjusting device 2.

In the production method of the present invention, water is attached to the warp by the water application device 4 immediately before being sent to the back roll 3. The water application device 4 includes a water tank 4a and a roller 4b having substantially half immersed in the water tank 4a. Water is applied by bringing a warp into contact with the surface of the roller 4b. When the warps come into contact with the roller 4b, the warps are already arranged in a sheet shape, and water is uniformly applied to the entire warp and then guided to the back roll 3.

The amount of water adhering to the warp is adjusted by the roller 4
b, the contact length of the warp with respect to b, the number of rotations of the roller 4b,
It can be freely adjusted by the warp tension or the like. The diameter of the roller 4b is preferably set to 50 to 100 mmφ in consideration of bending damage due to contact with carbon fibers. The amount of water attached is not particularly limited as long as the generation of fluff and dust generation can be suppressed.

The warp yarn to which water has been applied is impregnated with water between the fibers by the back roll 3, and after excess water has been removed to some extent, the water is sufficiently squeezed by the squeezing guide 5 until a suitable adhesion amount is obtained. While the yarn width and yarn arrangement are defined. The pitch of the guide 5 can be appropriately changed depending on the thickness of the warp, the number of filaments, and the density. The warp passing through the squeezing guide 5 is guided to the reed 7 via the heald 6.

At this time, the yarn having a small amount of the sizing agent attached thereto and having insufficient bunching property generates fluff due to contact between adjacent yarns due to the vertical movement of the heald 6 and rubbing when passing through the reed 7. Troubles such as poor opening and thread breakage of No. 6 occur. However, in the present invention, even when the amount of the sizing agent attached to the carbon fiber multifilament is as small as 1.0% or less, the multifilament has a water wet yarn width reduction rate of 30%.
However, since water is adhered to the warp yarn immediately before the back roll 3, sufficient convergence can be obtained, and generation of fluff and dust can be suppressed.

The weft 8 is inserted through the opening of the heald 6, and a woven fabric is formed. Thereafter, it can be directly wound on the winding roller 10 via the front roll 9, but in this case, the woven fabric is wound without being sufficiently dried. In this case, depending on the drying state of the wound woven fabric, curing failure and voids due to resin are likely to occur,
Therefore, the mechanical properties are not sufficiently exhibited. Therefore, depending on the drying state of the wound woven fabric, it is necessary to perform hot-air drying, vacuum drying, or the like to remove moisture before prepreg processing.

However, in the present case, in the manufacturing process of the woven fabric, after the weaving, before the final winding, the fabric is dried at the position of the front roll 9 by a drying device. Examples of the drying device include a suction type as shown in FIG. In the drying device of the suction type, a roller 11 having a slit formed with a slit 11a is provided in front of the front roll 9, and water is removed by suction from the slit 11a when the woven fabric passes over the roller 11. are doing. In this method, the suction effect differs depending on the width of the slit 11a. The suction may be performed using an industrial blower motor, but the suction effect is weakened even if it is too large or too small.
Preferably, it is 3 to 5 mm. The slit roller 11 is not in contact with the woven fabric and has a distance of 10
It is preferable to set it within mm. Further, it is preferable that the front roll 9 is basically rotated in order to prevent misalignment of the woven fabric.

Alternatively, a hot roll type drying apparatus shown in FIG. 3 can be employed. Heat roll type drying equipment
Using a front roll 9 in which a pipe heater 12 is inserted, heat is conducted to the front roll 9 and drying is performed by contact with a woven fabric. If the surface temperature of the roll 9 is too high, the carbon fibers will be damaged, and if it is too low, the drying capacity will be reduced. Therefore, the appropriate temperature is preferably 70 to 130 ° C.

Further, as shown in FIG. 4, a hot air drying apparatus may be employed. The hot-air drying device blows hot air from a hot-air blower 13 onto a woven fabric passing over the front roll 9 from the upper surface of the front roll 9 for drying.
If the woven fabric surface is at least 70 ° C., the hot air temperature has a sufficient drying effect, so that it is not necessary to raise it more than necessary.

The drying method may be appropriately selected depending on the form of the woven fabric, and any method or a combination thereof can be used. In addition, the weaving speed of carbon fiber fabric by a general shuttle loom or rapier loom is 0.3 to
It is about 1.5 m / min, and it is possible to sufficiently remove water even in a process in which water is applied to the warp and continuous drying is performed while weaving, as in the present invention, which is industrially extremely effective.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. (Example 1) 12K (denier 4050 denier) for the warp,
0.4% sizing agent adhesion amount, 44.8% reduction rate of water wet yarn width
Using a carbon fiber (Pyrofil manufactured by Mitsubishi Rayon Co., Ltd.), water was applied by a water applicator, and the same 12 K as the warp was inserted as the weft to fabricate a woven fabric having a basis weight of 500 g / m ^2. Was performed. At this time, the warp yarn has sufficient convergence to withstand up-and-down movement of the heald, e-mail, and rubbing of the reed, and has good weavability without generation of fluff or dust during weaving, and Water was also sufficiently removed.

(Example 2) Carbon fiber (Pyrofil manufactured by Mitsubishi Rayon Co., Ltd.) having 3K (denier 1800 denier), a sizing agent adhering amount of 0.5%, and a water-wetting yarn width reduction rate of 31.4% was used for the warp yarn. After water was applied by a water application device, the same 3K as the warp was used as the weft, and a woven fabric having a basis weight of 200 g / m ² was woven under the same conditions as in Example 1; A drying treatment was performed. In Example 2, as in Example 1, weaving properties were very good, and moisture was sufficiently removed.

Example 3 1K (fineness: 900 denier) warp yarn, 0.8% sizing agent adhering amount, water wet yarn width reduction ratio: 4
Water was applied by a water application device using 0.8% carbon fiber (Pyrofil manufactured by Mitsubishi Rayon Co., Ltd.), and the same 1K as the warp was used as the weft under the same conditions as in Examples 1 and 2. After weaving a woven fabric having a basis weight of 65 g / m ^2, the fabric was dried with hot air at 100 ° C. by a hot air method. At that time, the weaving property was good and the water was sufficiently removed.

(Comparative Example 1) When weaving was carried out using the same yarn as in Example 2 without applying water, the fluff occurred frequently due to the contact between adjacent members and the rubbing against the reed due to the vertical movement of the heald, and the opening of the warp yarns This resulted in poor weaving.

(Comparative Example 2) Carbon fiber (Pyrofil manufactured by Mitsubishi Rayon Co., Ltd.) having 3K (denier 1800 denier), a sizing agent adhering amount of 1.5%, and a water-wet yarn width reduction ratio of 22.5% was used as the warp yarn. The same 3K as the warp was inserted into the weft without water application, and after weaving a woven fabric having a basis weight of 200 g / m ² , water was removed by a suction method. The weaving property was good without any particular problem. . However, since the amount of the sizing agent attached is large, the impregnating property of the matrix resin is poor when the prepreg is manufactured later. Further, since the reduction rate of the width of the water-wetted yarn was small, a gap was observed between the single fibers of the warp in the obtained woven fabric.

[0038]

[Table 1]

As described above, according to the present invention, when weaving is performed using carbon fibers having an insufficient sizing property with an adhesion amount of the sizing agent of 1.0% or less, the reduction rate of the water-wetted yarn width is 30% or more. To adopt a certain carbon fiber and weave by attaching water,
The resulting woven fabric is densely and uniformly woven with no gaps between the single fibers. In addition, since sufficient convergence is imparted by the adhesion of water, rubbing between adjacent yarns due to vertical movement of the heald, generation of fluff and dust due to rubbing with mail and reeds can be effectively suppressed, and weaving can be improved. Let it. The drying process can be continuously performed, the productivity is greatly improved, and the production cost of the fabric can be significantly reduced.

Further, since the water is applied immediately before the back roll, there is no inconvenience such as yarn sway at the opening of the warp. Further, by applying water by bringing almost half of the roller into contact with the surface of the submerged roller, water can be applied uniformly to the entire warp yarn. Moreover, since there is no water splash, there is no effect on peripheral devices.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a method for producing a reinforcing fiber woven fabric of the present invention.

FIG. 2 is a schematic diagram of a drying apparatus suitably used in the production method of the present invention.

FIG. 3 is a schematic view of another drying apparatus suitably used in the production method of the present invention.

FIG. 4 is a schematic view of still another drying apparatus suitably used in the production method of the present invention.

[Explanation of symbols]

 Reference Signs List A Carbon fiber (warp) 1 Supply roller 2 Warp tension adjusting device 3 Back roll 4 Water application device 4a Water tank 4b Roller 5 Squeeze guide 6 Heald 7 Reed 8 Weft 9 Front roll 10 Winding roller 11 Slit roller 11a Slit 12 Pipe heater 13 Hot air blower

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D06M 11/05 D06M 101: 40 // D06M 101: 40 7/00 A (72) Inventor Yoshio Samejima Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory 4-72, Sunadabashi, Higashi-ku, Nagoya-shi (72) Inventor Mitsuo Tanaka 4-1-1 Sunadabashi, Higashi-ku, Nagoya City, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory F-term (reference) 4L031 AA27 AB04 BA08 4L043 AA02 AA07 BB08 BC03 4L048 AA05 AA48 AA49 AA53 AB07 AB11 AB13 AB27 AC09 AC10 AC14 CA01 CA02 CA15 DA41

Claims (6)

[Claims] 1. A weaving process in which a carbon fiber multifilament having a sizing agent adhesion amount of 1.0% or less and a water-wet yarn width reduction rate of 30% or more is used as at least a warp yarn and the warp yarn is provided with moisture. A method for producing a reinforcing fiber woven fabric. 2. The method for producing a reinforcing fiber woven fabric according to claim 1, further comprising a step of imparting moisture to said carbon fiber multifilament immediately before a back roll. 3. The method according to claim 2, further comprising a step of defining a yarn width and an arrangement between the back roll and the heald while squeezing water of the carbon fiber multifilament by a squeezing guide. A method for producing a reinforcing fiber woven fabric. 4. The method for producing a reinforcing fiber woven fabric according to claim 1, further comprising a step of performing a drying treatment continuously after weaving. 5. The method for producing a reinforcing fiber woven fabric according to claim 1, wherein the carbon fiber multifilament having a number of filaments of 500 or more is used. 6. The method for producing a reinforcing fiber woven fabric according to claim 1, wherein the basis weight of the woven fabric is 50 to 600 g / m ² .