JPH09254227A - Thermoplastic resin-covered reinforcing fiber bundle and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain flexibility and excellent mechanical characteristics and to prevent wrinkles during deep draw from being generated by cutting partly a fiber bundle at intervals and shifting positions in the width direction of adjacent cut parts. SOLUTION: A resin-covered reinforcing fiber bundle is partly cut successively from an end part a, a central part b and another end part c by passing it through a rotary cutter to obtain a thermoplastic resin-covered reinforcing fiber bundle. E.g. the cut length L' of the filament at the end part a is made 10-60mm and the cut lengths of the central part b and another end part c are also made the same. As this molding material has flexibility, it well conforms to a mold and as the reinforcing fiber is cut, no excessive load is applied on the reinforcing fiber even when deep draw molding is performed and there exists no possibility of generating wrinkles on the surface and cutting of the reinforcing fiber at corner parts. As the reinforcing fiber, inorg. fibers such as glass fiber and carbon fiber, org. fibers such as aramide fiber and polyethylene fiber, metal fibers such as boron fiber and alumina fiber are cited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composite molding material, and more particularly to a thermoplastic resin-coated reinforced fiber bundle which enables a molding material having excellent mold conformability during molding.

[0002]

2. Description of the Related Art Conventionally, composites using a thermosetting resin as a matrix resin have been the mainstream. However, in recent years, a composite using a thermoplastic resin as a matrix resin has been developed from the viewpoints of shortening the molding cycle, easy recycling, post-processing capability, clean working environment, and improved impact resistance. Therefore, the development of a molding material that has a good moldability and enables a composite having excellent physical properties has become a major issue. Japanese Examined Sho 63-
In 37694, the reinforcing fiber is directly impregnated with the molten resin,
Although the solidified molding material is described here, in order to complete the impregnation of the resin into the reinforcing fiber,
A method is adopted in which the melt viscosity of the resin is lowered and the resin is impregnated by squeezing with a bar provided in the resin bath. Therefore, the obtained molding material has a high degree of impregnation and is extremely hard, which causes a problem that it is difficult to follow the mold during molding.

Japanese Examined Patent Publication No. 3-35100 describes a resin as a solvent,
After making a solution or emulsion and impregnating the reinforcing fibers, a solvent,
A molding material from which the dispersion has been removed is described. In this case, the impregnation is relatively easy, but it is difficult to completely remove the solvent or dispersion after the impregnation. Further, if the degree of impregnation is increased, it becomes a hard material, which causes a problem that it is difficult to fit in the mold during molding. JP-A-60-209033 and 60-209034 describe a molding material in which a resin is fibrous and mixed with reinforcing fibers, and JP-A-60-28543 describes a molding material in which resin fibers and reinforcing fibers are interwoven. ing. In this case, regarding the former two, the obtained molding materials are flexible, easy to follow the mold, and easy to handle, but wrinkles occur in a complicated shape such as a box shape. What is common to all of these molding materials is that since continuous fibers are used as reinforcing fibers, deep drawing and wrinkles occur in complicated shapes.

[0004]

The present invention has an excellent flexibility as a molding material, gives excellent mechanical properties when formed into a molded product, and is excellent in that no wrinkles are formed during deep drawing. The purpose is to develop a moldable material.

[0005]

The present invention is directed to solving the above-mentioned problems by providing a reinforcing fiber bundle coated with a thermoplastic resin, wherein the fiber bundle is partially cut at intervals,
Moreover, it has been discovered that this is possible by using a thermoplastic resin-coated reinforced fiber bundle in which the positions of adjacent cut portions are displaced in the width direction. The number of filaments of the reinforcing fiber bundle in the present invention is 3000 to 15000.
It is preferable that a reinforcing fiber bundle of a book is used, and that the interval between the cut portions of the reinforcing fiber bundle is in the range of 10 to 60 mm. By using the thermoplastic resin-coated reinforcing fiber bundle of the present invention as warp and weft as a woven fabric, a more suitable molding material can be obtained. It is also possible to use a sleeve. Further, the thermoplastic resin-coated reinforced fiber bundle, the woven fabric using the same, and a thermoplastic resin composite molded article using a sleeve as a molding material are also included in the scope of the present invention. The reinforcing fiber bundle of the present invention, when cutting the reinforcing fiber bundle coated with a thermoplastic resin by a rotary cutter, the blade width is equal to or smaller than the width of the fiber bundle, and the position of the blade is shifted in the width direction. Can be manufactured by partially cutting the reinforcing fiber bundle.

[0006]

The reinforcing fibers of the molding material of the present invention include inorganic fibers such as glass fibers and carbon fibers, organic fibers such as aramid fibers and polyethylene fibers, and further boron fibers.
There are metal fibers such as alumina fibers, but they are not particularly limited to these, and two or more kinds of these reinforcing fibers may be used in combination. In the case of the present invention, these reinforcing fibers are used as a fiber bundle having a filament number of 3000 to 15000, preferably 6000 to 12000. Further, the filament diameter of the reinforcing fiber is 5 to 20 μm,
It is preferably used in the range of 7 to 10 μm. As a method for coating the reinforcing fiber bundle with the thermoplastic resin, the method according to Japanese Patent Application No. 7-169247 already filed by the applicant of the present invention is preferable, but the method is not limited thereto.

In this method, as shown in FIG. 3, the reinforcing fiber bundle 3 is passed through the center of the die 4 for extruding the molten thermoplastic resin 7 onto the cylinder, and the molten resin 7 immediately after leaving the die is brought into contact with the die to coat the resin. Is. The feature is that the resin is hardly impregnated in the fiber bundle because it can be coated without pressure.
When the fiber bundle is impregnated with the resin, the coated fiber bundle becomes rigid, so that the mold conformability to the mold becomes poor as a composite molding material. The thermoplastic resin-coated fiber bundle that can be used in the present invention preferably has a resin impregnation degree of 50% or less of the total cross-sectional area of the filaments forming the fiber bundle. The fiber bundle coated with resin is air-cooled,
Alternatively, it is water-cooled and wound up, but flattened while passing between the rollers. The width of the resin-coated fiber bundle used in the present invention is preferably 3 mm or more and about 4 to 10 mm.

The thermoplastic resin used for coating the reinforcing fiber bundle of the present invention includes polyamide resins such as nylon 6, nylon 12, nylon 66 and aromatic nylon, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyethylene, Examples include olefin resins such as polypropylene, polyether ether ketone resins, polyetherimide resins, polyether sulfone resins, polyphenylene sulfide resins, and polycarbonate resins, but are not particularly limited thereto, and these heat You may use together 2 or more types of plastic resins. In the resin-coated reinforcing fiber bundle of the present invention, the volume content of reinforcing fibers is preferably 30 to 75%.
Therefore, the volume content of the thermoplastic resin is 75 to 30%. This is because if the volume content of the thermoplastic resin is less than 30%, it is difficult to uniformly coat, and the formed coating film is thin, which may cause problems such as peeling in a later step. On the contrary, the volume content of the thermoplastic resin is set to 7
When it is more than 5%, the resin content becomes too much, and the mechanical strength of the molded body becomes insufficient.

The thermoplastic resin-coated reinforced fiber bundle is supplied to the pull roller through the yarn guide and then supplied to the rotary cutter to be partially cut. Rotary cutter
It is composed of a cutter roll in which a cutting blade is embedded and a rubber roll installed so as to face the cutter roll. The cutting blade has a width of 5
A roll having a size of less than or equal to mm is used, and the roll is mounted with its position shifted in the width direction. Explaining with reference to FIG. 2, for example, the width of the resin-coated fiber bundle is 4 mm, two types of cutting blades of 4 mm and 2 mm are used, and 4 mm (A ), 2 mm (B), 4 mm
In the order of (C), these three blades are mounted so as to be displaced while overlapping about 0.1 to 0.2 mm in the width direction of the roll. The resin-coated fiber bundle 5 is supplied to the cutter so that the cutting blade (B) is located at the center of the fiber bundle. First, one end of the fiber bundle is partially cut by the cutting blade (A), then the central portion of the fiber bundle is partially cut by the cutting blade (B), and then the other end of the fiber bundle is cut by the cutting blade ( It is partially cut by C). Therefore, the cutting blades (A), (B),
At least 1 filament of the fiber bundle while passing through (C)
The times will be cut. The cutting blades are arranged at regular intervals, and a blade having a width of 4 mm is mounted at the position (A) in the width direction,
Similarly, it is attached to the positions of (B) and (C). In the case of the present invention, the distance L from (A) to the next (A) is 10 to 60 m.
m is desirable.

By passing through the rotary cutter as described above, the resin-coated reinforcing fiber bundle 5 is partially cut in the order of the end portion (a), the central portion (b) and the other end portion (c) as shown in FIG. By repeating this, the thermoplastic resin-coated reinforced fiber bundle 1 of the present invention is obtained. FIG. 1 schematically shows an example of the thermoplastic resin-coated reinforced fiber bundle of the present invention. FIG.
As shown in, for example, the cutting length L ′ of the filament at the end (a) is in the range of 10 to 60 mm. The cut lengths of the filaments in the central portion (b) and the other end portion (c) are also the same. Since the thermoplastic resin covers the periphery of the fiber bundle, it looks like a continuous fiber bundle, but the internal reinforcing fiber bundle is basically 10-60 although the cut portion is displaced.
It has been cut to lengths in the range of mm. In the above description,
Although the partial cut in the width direction of the fiber bundle is divided into three parts, it can be cut at two parts, and the cut length at each part may be constant, but within the range of 10 to 60 mm. If so, it does not necessarily have to be constant. In addition, the cutting blade is attached to the cutter roll in a roll width direction of 0.1 to prevent the generation of uncut filaments.
It is desirable to overlap by about 0.2 mm.
The cutting length of the filament is 10 to 60 mm,
If it is shorter than 10 mm, a sufficient reinforcing effect cannot be obtained when the composite is molded. If it is longer than 60 mm, wrinkles are likely to form on the surface of the molded product during deep drawing or molding of a complicated shape.

The thermoplastic resin-coated reinforcing fiber bundle of the present invention comprises
The molding material can be used as it is. Also,
It is also possible to weave the resin-coated fiber bundle as warp and weft to obtain a woven material. This woven material is
Since it has flexibility, it is easy to fit in the mold.Because the constituent reinforcing fibers are cut, even in the case of deep-drawing, the reinforcing fibers are not subjected to an unreasonable load and the surface of the molded body is not affected. Wrinkles do not occur and reinforcing fibers do not cut at the corners. Since the cut length of the reinforcing fibers is in the range of 10 to 60 mm, the strength of the obtained composite is sufficiently retained. Alternatively, a resin-coated fiber bundle may be braided as a constituent yarn to form a sleeve-shaped molding material. When weaving or braiding the resin-coated fiber bundle of the present invention, heat treatment can be performed in advance. Since the cut portion is partially cut, the cut portion may be caught by the guide or the reed of the loom. Therefore, heat treatment can be performed in advance to melt and repair the resin in the cut portion, and the risk thereof can be reduced.

[0012]

【Example】

Example 1 6K carbon fiber (filament diameter 7 μm,
The number of filaments (6000) is coated with nylon 66 resin using the coating device shown in FIG.
A resin-coated carbon fiber bundle having a carbon fiber volume content of 50% was wound up. The width of the wound resin-coated carbon fiber bundle was about 4 mm, and the cross-sectional shape was flat. As shown in FIG. 2, this resin-coated carbon fiber bundle was cut with a blade width of 4 mm (A), 2
The cutting blades of mm (B) and 4 mm (C) are shifted in the width direction of the cutter roll, and the cutting blades of A, B, and C are overlapped by 0.1 mm in the width direction, and the blade next to C is the width direction. At the position A, the blades AA are mounted so that the distance L between the blades is 40 mm, and the blades B and C are passed through a cutter roll mounted so that the blades AA have substantially equal intervals, and the blade roll is about 13 mm. A nylon resin-coated carbon fiber bundle partially cut at an interval of was obtained. The obtained fiber bundle appears continuous because it is coated with resin, but the filaments are in principle cut at 40 mm intervals. This resin-coated carbon fiber bundle was woven at a weave density of 10 warps and 10 wefts. 10 sheets of this woven fabric are stacked, molding temperature 270 ℃, molding pressure 10kg
f / cm ² , holding time 20 minutes, 100 mm x 150 m
A m × 30 h box-shaped molded body was prepared, and moldability and mechanical properties were evaluated. The formability was evaluated by visually observing the occurrence of wrinkles in four corners, and the mechanical properties were measured by cutting a sample from the bottom and measuring the bending strength. The measuring method is according to ASTM D-790. The results are shown in Table 1.

<Embodiment 2> Cutting blade AA in Embodiment 1
The same procedure as in Example 1 was performed except that the distance between them was 10 mm.

Comparative Example 1 The same woven fabric as in Example 1 was woven without partial cutting of the nylon resin-coated carbon fiber bundle obtained in Example 1 to form a molded article similar to that in Example 1. The formability and mechanical properties were evaluated. The results are shown in Table 1.

<Comparative Example 2> 6K carbon fiber bundles and nylon fibers of 6/6 carbon fiber and 6/6 weft carbon fiber and nylon fiber so that the carbon fiber content rate is 50%. A woven fabric was obtained by weaving at a weaving density. 17 sheets of this woven fabric were stacked to form a box-shaped molded article under the same conditions as in Example 1, and the moldability and mechanical properties were evaluated.

[0016]

EFFECTS OF THE INVENTION The thermoplastic resin-coated reinforced fiber bundle of the present invention is continuous because it is coated with resin, but the constituent filaments are cut. Therefore, the molding material using the fiber bundle is deep drawn. Good moldability for molded products and molded products with complicated shapes. Also, since the filaments that are cut have a fixed length, molded products with mechanical properties comparable to conventional products can be obtained. To be The thermoplastic resin-coated reinforced fiber bundle of the present invention has flexibility because the coating resin is hardly impregnated in the reinforced fiber bundle, and therefore the molding material using this fiber bundle has excellent shapeability. There is. Further, since the thermoplastic resin-coated reinforced fiber bundle of the present invention is uniformly coated with the thermoplastic resin around the fiber bundle, it also has an advantage that the resin bundle has a good impregnation property during molding.

[Brief description of drawings]

FIG. 1 is an enlarged schematic view of a thermoplastic resin-coated reinforced fiber bundle of the present invention.

FIG. 2 is a partially enlarged schematic view of a cutter roll used in the method for producing a thermoplastic resin-coated reinforced fiber bundle of the present invention.

[Fig. 3] Example of resin coating method for reinforcing fiber bundle

[Explanation of symbols]

 1. Thermoplastic resin-coated reinforcing fiber bundle of the present invention a, b, c. Partial cutting part 2. Cutter roll A, B, C. Cutting blade 3. Reinforcing fiber bundle 4. Dice 5. 5. Thermoplastic resin-coated reinforced fiber bundle 6. Resin melt extrusion section 7. Molten resin

[Table 1]

Claims (7)

[Claims] 1. A reinforcing fiber bundle covered with a thermoplastic resin, wherein the fiber bundle is partially cut at intervals, and adjacent cut portions are displaced in the width direction. A thermoplastic resin-coated reinforced fiber bundle characterized by: 2. A thermoplastic resin-coated reinforcing fiber bundle in which the number of filaments of the reinforcing fiber bundle in claim 1 is 3000 to 15000. 3. A thermoplastic resin-coated reinforcing fiber bundle in which the distance between the cut portions of the reinforcing fiber bundle according to claim 1 or 2 is in the range of 10 to 60 mm. 4. A thermoplastic resin composite molding material, which is a woven fabric comprising the thermoplastic resin-coated reinforced fiber bundle according to claim 1, 2 or 3 as warp yarns and weft yarns. 5. A thermoplastic resin composite molding material, which is a sleeve comprising the thermoplastic resin-coated reinforced fiber bundle according to claim 1, 2, or 3 as a constituent thread. 6. A thermoplastic resin composite molded article, which is molded using the thermoplastic resin composite molding material according to claim 1, 4, or 5. 7. When cutting a reinforcing fiber bundle coated with a thermoplastic resin with a rotary cutter, the blade width is made equal to or smaller than the width of the reinforcing fiber bundle, and the position of the blade is shifted in the width direction, A method for producing a thermoplastic resin-coated reinforced fiber bundle, which comprises partially cutting the reinforced fiber bundle.