JPH06278234A - Production of frtp molded product and preform - Google Patents

Abstract

PURPOSE:To efficiently produce an FRTP product using a preform capable of obtaining the FRTP molded product excellent in physical properties and reduced in irregularity. CONSTITUTION:A preform constituted by alternately winding carbon fiber braids and nylon braids around a rubber tube is introduced into a mold and heated to melt the nylon braids and the molten nylon resin of the nylon braids is infiltrated in the carbon fiber braids to obtain an FRTP molded product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to the production of bicycle frames, tennis racket frames, golf shafts, ski poles, baseball bats and other, preferably tubular molded articles made of FRTP (fiber reinforced thermoplastic). Regarding the preform to use. The present invention also provides FRTP using such a preform.
The present invention relates to a method for manufacturing a molded article.

[0002]

2. Description of the Related Art FRTP molded products have superior damping characteristics to FRP (fiber reinforced plastic) molded products that use a thermosetting resin as a matrix. It is preferably used for applications where vibration damping is especially required. Therefore, there is a strong demand for the development of a preform capable of efficiently producing such a tubular FRTP molded product.

As such a preform, there is known a braid which uses a mixed fiber yarn of reinforcing fibers and thermoplastic resin fibers at a single fiber level. In the production of FRTP molded articles using this preform, thermoplastic resin fibers are melted to form a matrix. However, there are problems as described below.

That is, particularly when the reinforcing fiber is a brittle fiber such as carbon fiber, the reinforcing fiber is often broken during the process of producing the mixed fiber, and the physical properties of the obtained FRTP molded product are deteriorated or dispersed. Will become larger. Further, since the reinforcing fibers and the thermoplastic resin fibers have greatly different tensile elastic moduli, when the mixed fiber is processed into a braid, the reinforcing fibers and the thermoplastic resin fibers are separated into a bundle by the tension applied to the mixed fiber. As a result, the dispersion of the reinforcing fiber and the thermoplastic resin fiber in the braid tends to be non-uniform, and the physical properties of the obtained molded product are deteriorated or the dispersion is increased. Furthermore, in the case of manufacturing a thick-walled tubular body, a large number of braids must be overlapped prior to the molding work, which is not only poor in workability, but also the braided yarns that make up the braid at the time of stacking. The orientation of is disturbed, and similarly, the physical properties of the obtained molded product are deteriorated or the dispersion is increased.

There is also provided a preform composed of a hybrid braid in which one reinforcing fiber yarn and one thermoplastic resin fiber yarn are alternately arranged, but there is a problem described below.

That is, while the reinforcing fiber yarn hardly shrinks, the thermoplastic resin fiber yarn is stretched during its manufacturing process, and since tension is applied when it is processed into a braid, the thermoplastic resin fiber yarn is stretched during molding. The thermoplastic resin fiber yarn shrinks, the orientation of the reinforcing fiber yarn is disturbed, and the physical properties of the obtained FRTP molded product are deteriorated or the dispersion becomes large.
In addition, the arrangement of the thermoplastic resin fiber yarns is alternating, and it melts at the time of molding. Therefore, in the molded product, that portion is made of only the thermoplastic resin, and the reinforcing fiber does not exist. Physical properties of the product deteriorate or the dispersion becomes large. Furthermore, in the case of manufacturing a thick-walled tubular body, a large number of braids must be piled up prior to molding, which is not only poor in workability, but also the braided yarns that make up the braid at the time of stacking. The orientation of is disturbed, and similarly, the physical properties of the obtained molded product are deteriorated or the dispersion is increased.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of conventional preforms and to provide a preform having excellent physical properties and capable of obtaining a FRTP molded product having a small variation. There is. Also,
Another object of the present invention is to provide a method for producing a FRTP molded article using such a preform and having excellent workability during production.

[0008]

To achieve the above object, the present invention is characterized in that a core material is covered with a tubular reinforcing fiber base material and a tubular thermoplastic resin fiber base material. Provide reform. It is preferable that the reinforcing fiber base material and the thermoplastic resin fiber base material are alternately covered. A flexible tube is usually used as the core material. The reinforcing fiber base material and the thermoplastic resin fiber base material are preferably round braids. As a round braid, reinforcing fiber threads are arranged at an angle of ± α ° with respect to the length direction.
Braid, braided fibers arranged in the longitudinal direction, and braided fibers arranged at an angle of ± α ° with respect to the lengthwise braided braid, and reinforcing arranged in the longitudinal direction Fiber yarn,
There is a triaxial braid consisting of thermoplastic resin fiber auxiliary yarns arranged at an angle of ± α ° with respect to the length direction. The biaxial braid in which the reinforcing fiber yarns are arranged at an angle of ± α ° with respect to the length direction, the reinforcing fiber yarns arranged in the length direction and the angle of ± α ° with respect to the length direction It is also preferable to use together with a triaxial braid consisting of a thermoplastic resin fiber auxiliary thread. Further, it is preferable that a thermoplastic resin fiber base material is arranged in the innermost layer and the outermost layer. Furthermore, the volume ratio of the reinforcing fiber base material to the thermoplastic resin fiber base material is 40:60 to 65:
It is preferably in the range of 35.

The present invention also provides a method for producing an FRTP molded product using the above-mentioned preform, which comprises a core material alternately covered with a tubular reinforcing fiber base material and a tubular thermoplastic resin fiber base material. Provided is a method for producing a FRTP molded article, which comprises placing a reform in a mold and heating it to melt the thermoplastic resin fiber base material and impregnating the reinforcing fiber base material with the thermoplastic resin resulting from the melting. . The core material is preferably made of a flexible tube, and the inside of the core material is pressurized during molding.

The preform of the present invention is constructed by covering the core material with a tubular reinforcing fiber base material and a tubular thermoplastic resin fiber base material.

The core material is for maintaining the shape during the production of the preform and for imparting an internal pressure during the molding, and is made of polyethylene resin, polystyrene resin, polypropylene resin, polyvinyl chloride resin, acrylic resin, polyester resin, fluorine. Resin, nylon resin, ABS resin, PBT
Resins such as resins, foams of these resins, films,
It is made of rubber such as butadiene rubber or silicone rubber, or metal, and is in the form of a rod or tube. When a flexible core material is used, the preform can be continuously manufactured while being wound into a roll.

The tubular reinforcing fiber base is usually prepared as a round braid. As is well known, such a braid includes a biaxial braid in which reinforcing fiber threads are arranged at an angle of ± α ° with respect to the length direction, a reinforcing fiber thread arranged in the length direction, and There is a triaxial braid consisting of reinforcing fiber yarns arranged at an angle of ± α ° with respect to the length direction. However, the triaxial braid has a large bending of the reinforcing fiber yarns and the reinforcing effect is small accordingly, so the biaxial braid Is preferably used. However, if only the biaxial braid is used, the reinforcing fibers are not arranged in the length direction of the FRTP molded product. If this is inconvenient, it is advisable to use a triaxial braid consisting of reinforcing fiber yarns arranged in the length direction and thermoplastic resin fiber auxiliary yarns arranged at an angle of ± α ° with respect to the length direction. The auxiliary thread is
It is made of the same yarn as the thermoplastic resin fiber yarn constituting the thermoplastic resin fiber base material described later. However, it is usually thinner than the thermoplastic resin fiber yarn that constitutes the thermoplastic resin fiber base material.

FIG. 1 shows an example of the structure of a round-spun biaxial braid. In the structure shown in FIG. 1, the reinforcing fiber yarns are arranged at an angle of ± α ° with respect to the longitudinal direction of the braid (vertical direction in FIG. 1), and the reinforcing fiber yarns 1 in the + α ° direction are-
Interleave with two reinforcing fiber threads 2 in the α ° direction alternately, and
Two reinforcing fiber yarns 2 in the α ° direction are interlaced with two reinforcing fiber yarns 1 in the + α ° direction. It is a jump organization between two. In addition to such a two-spacing structure, a one-spacing structure, a three-spacing structure, or a four-spacing structure may be used. The two-distance flying structure, the three-distance flying structure, and the four-distance flying structure improve the drapeability of the braid, which is convenient for obtaining a bent FRTP molded product such as a tennis racket frame.

As described above, the reinforcing fiber yarns in the braid are arranged at an angle of ± α ° with respect to the length direction, and the range of this angle α is 30 to 60, preferably 45.
Is. That is, when the reinforcing fiber yarns are arranged in the direction of ± 45 °, it is possible to effectively reinforce against torsion, and it is possible to obtain a FRTP molded product having large torsion strength and rigidity with a small amount of reinforcing fibers. Like

The reinforcing fiber yarns constituting the braid are high-strength and high-modulus fiber yarns such as carbon fiber yarns, glass fiber yarns, polyaramid fiber yarns and silicone carbide fiber yarns.
Two or more kinds can be used together. Above all, when constructing a tennis racket frame, a bicycle frame, etc., the tensile elastic modulus is 7,000 kgf because of the large weight reduction effect.
/ Mm ² or more, the use of carbon fibers as tensile strength is 200 kgf / mm ² or more.

The thickness of the reinforcing fiber yarn, that is, the cross-sectional area, is preferably about 0.10 to 0.25 mm ² . If the cross-sectional area becomes too large, the thermoplastic resin generally has a higher viscosity than the thermosetting resin,
Impregnating property into the reinforcing fiber base material during molding becomes poor.

It is preferable that the number of twists of the reinforcing fiber yarn is substantially zero, but it may be considered that the number of twists up to about 15 times per 1 m is substantially untwisted. Similar to the cross-sectional area, if the number of twists is too large, the impregnating property into the reinforcing fiber base material will deteriorate.

On the other hand, the thermoplastic resin fiber base material is also usually prepared as a round braid, like the reinforcing fiber base material. The only difference is that the yarns constituting it are not the reinforcing fiber yarns but the thermoplastic resin fiber yarns. That is, this thermoplastic resin fiber base material is melted during molding and impregnated into the reinforcing fiber base material to form the matrix of the FRTP molded product. So nylon fiber, for example nylon 6 fiber,
Nylon 66 fiber, nylon 12 fiber, polyether ether ketone fiber, polyether imide fiber, polyphenylene sulfide fiber, polyester fiber, ABS
It is composed of yarns made of thermoplastic fibers such as fibers, polyethylene fibers and polypropylene fibers. These may be multifilament yarns or spun yarns. Incidentally, when the number of braids, that is, the number of yarns constituting the braid, is made larger than that of the reinforcing fiber base material, the thermoplastic resin fibers are more uniformly present around the reinforcing fiber base material, It is preferable because the reinforcing fiber base material is more uniformly impregnated during molding. If the arrangement angle (α) is offset from that of the reinforcing fiber substrate by 3 to 10 °, the reinforcing fiber yarn and the thermoplastic resin fiber yarn are less overlapped with each other, and the occurrence of voids during molding is suppressed. become able to.

The preform of the present invention is constructed by covering the above-mentioned core material with the above-mentioned reinforcing fiber base material and thermoplastic resin fiber base material. In order to improve the resin impregnation property and obtain a FRTP molded product having excellent uniformity of distribution of reinforcing fibers or thermoplastic resin, a thermoplastic resin fiber base material is arranged in the innermost layer and the outermost layer, and at the same time, a reinforcing fiber base material is provided. It is preferable that the material and the thermoplastic resin fiber base material are alternately arranged.

The volume ratio of the reinforcing fiber base material to the thermoplastic resin fiber base material is related to the reinforcing fiber volume content of the resulting FRTP molded article, and is preferably in the range of 40:60 to 65:35. Within this range, a molded product having excellent physical properties and surface quality can be obtained. It should be noted that this range can be easily adjusted by changing the thickness, arrangement density, etc. of the reinforcing fiber yarn or the thermoplastic resin fiber yarn constituting the reinforcing fiber substrate or the thermoplastic resin fiber substrate.

FRT using the preform of the present invention
The P-molded article is manufactured by placing the preform in a mold, heating it to melt the thermoplastic resin fiber base material, and impregnating the reinforcing fiber base material with the thermoplastic resin resulting from the melting. When using a flexible tube as the core material,
3 to 20 in the core material using air, nitrogen gas, carbon dioxide gas, etc.
It can be pressurized to a pressure of about kgf / cm ^2. After the thermoplastic resin is solidified, that is, after the molding is completed, the pressurization is released and the mold is released. In any of the above cases, the core material may be left as it is after the molding, or may be extracted. Further, the heating temperature is preferably in the range of 30 to 70 ° C. so that the impregnation property of the thermoplastic resin is further improved.

[0022]

The preform of the present invention comprises a core material covered with a tubular reinforcing fiber base material and a tubular thermoplastic resin fiber base material, and comprises a reinforcing fiber base material and a thermoplastic resin fiber base material. Since it can be prepared separately from the above, there is no fear of damaging the reinforcing fiber, which is a problem of the above-mentioned conventional preform. Also, since the core material is used, even if the thermoplastic resin fiber yarn of the thermoplastic resin fiber base material contracts, the arrangement of the reinforcing fiber base material can be disturbed just by tightening the core material. There is no. Furthermore, by appropriately selecting the numbers of the reinforcing fiber base material and the thermoplastic resin fiber base material, a thick FRTP molded product can be easily manufactured, and since these are pre-coated, they are not covered during molding. The workability is improved, and the disorder of the arrangement of the reinforcing fiber yarns can be prevented.
Furthermore, the preform of this invention puts it in a mold,
A FRTP molded article can be produced by simply heating to melt the thermoplastic resin fiber base material and impregnating the reinforcing fiber base material with the thermoplastic resin resulting from the melting. From these, according to the present invention, it is possible to efficiently manufacture an FRTP molded product having excellent physical properties and a small variation.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a braid made of reinforcing fiber yarn used in the present invention.

[Explanation of symbols]

 1: Reinforcing fiber yarn 2: Reinforcing fiber yarn

Claims (12)

[Claims] 1. A preform comprising a core material covered with a tubular reinforcing fiber base material and a tubular thermoplastic resin fiber base material. 2. The preform according to claim 1, wherein the reinforcing fiber base material and the thermoplastic resin fiber base material are alternately covered. 3. The core material is a flexible tube.
Or a preform of 2. 4. The preform according to claim 1, 2 or 3, wherein the reinforcing fiber base material and the thermoplastic resin fiber base material are round braided braids. 5. A biaxial braid, wherein the reinforcing fiber base material includes reinforcing fiber threads arranged at an angle of ± α ° with respect to the longitudinal direction.
The preform according to claim 1, 2 or 3. 6. A reinforcing fiber base material is a triaxial braid including reinforcing fiber yarns arranged in a length direction and reinforcing fiber yarns arranged at an angle of ± α ° with respect to the length direction. The preform according to claim 1, 2 or 3. 7. A triaxial braid in which a reinforcing fiber base material includes reinforcing fiber yarns arranged in a length direction and thermoplastic resin fiber auxiliary yarns arranged at an angle of ± α ° with respect to the length direction. The preform according to claim 1, 2 or 3, wherein 8. A preform according to claim 1, 2 or 3, comprising the reinforcing fiber base material according to claim 5 and the reinforcing fiber base material according to claim 7. 9. The preform according to claim 1, 2 or 3, wherein a thermoplastic resin fiber base material is arranged in the innermost layer and the outermost layer. 10. The preform according to claim 1, 2 or 3, wherein the volume ratio of the reinforcing fiber base material to the thermoplastic resin fiber base material is in the range of 40:60 to 65:35. 11. A preform having a core material covered with a tubular reinforcing fiber base material and a tubular thermoplastic resin fiber base material is placed in a mold and heated to melt the thermoplastic resin fiber base material and A method for producing a FRTP molded article, characterized in that the reinforcing fiber base material is impregnated with a thermoplastic resin by melting. 12. A preform obtained by covering a tubular reinforcing fiber base material and a tubular thermoplastic resin fiber base material on a core material made of a flexible tube is placed in a mold and heated while pressurizing the inside of the core material. A method for producing a FRTP molded article, characterized in that the above-mentioned thermoplastic resin fiber base material is melted and the thermoplastic resin resulting from the melting is impregnated into the reinforcing fiber base material.