JP2013000933A - Fiber-reinforced thermoplastic resin molded article and method for producing the same, and composite body and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber-reinforced thermoplastic resin molded article suitable for a material of a composite body exhibiting high mechanical characteristics, a method for producing it, a composite body exhibiting high mechanical characteristics, and a method for producing it.SOLUTION: The fiber-reinforced thermoplastic resin molded article 10 includes: a shell part 20 whose cross-section is an open cross-sectional shape, and a rib part 30 provided in the inside of the shell part 20. In the fiber-reinforced thermoplastic resin molded article 10, the shell part 20 comprises a material S with a bending modulus higher than a material R constituting the rib part 30. The method for producing it is also provided. A plurality of the fiber-reinforced thermoplastic resin molded articles are connected by making the rib parts inside to form a closed cross-sectional shape. The method for producing it is also provided.

Description

  The present invention relates to a fiber-reinforced thermoplastic resin molded article and a production method thereof, and a composite and a production method thereof.

Parts made of reinforced fibers and thermoplastic resins (fiber reinforced thermoplastic resin molded products) are already known.
For example, Patent Documents 1 to 3 disclose a stamping molding material composed of a thermoplastic resin and short fibers and a stampable sheet.
Patent Document 4 discloses a stampable sheet in which a laminate of reinforcing long fibers and long fiber mats aligned in one direction is impregnated with a thermoplastic resin.

JP-A-5-9301 JP-A-6-313292 JP-A-7-88840 JP-A-9-216225

By the way, the fiber reinforced thermoplastic resin molded product is used in a case where a plurality of fiber reinforced thermoplastic resin molded products are integrated and used as a composite of fiber reinforced thermoplastic resin molded products than when used alone. There are many.
However, Patent Documents 1 to 4 do not have a description in which a plurality of stamping molding materials or stampable sheets are integrated to form a composite. Moreover, even if these were integrated, a composite having excellent mechanical properties could not be obtained.

  The present invention has been made in view of the above circumstances, and is a fiber-reinforced thermoplastic resin molded article suitable as a composite material exhibiting high mechanical properties, a method for producing the same, and a composite exhibiting high mechanical properties and the production thereof. Provide a method.

The fiber reinforced thermoplastic resin molded product of the present invention is a fiber reinforced thermoplastic resin molded product comprising a shell portion having a cross-section of an open cross section and a rib portion provided inside the shell portion, The portion includes a material S having a higher bending elastic modulus than the material R constituting the rib portion.
Here, at least a part of the material S is a tape-like or sheet-like base material obtained by impregnating a reinforced fiber aligned in one direction with a thermoplastic resin, or a laminate in which two or more base materials are laminated. It is preferable.
Moreover, it is preferable that at least a part of the material S is a woven fabric made of a tape in which a thermoplastic fiber is impregnated with reinforcing fibers aligned in one direction, or a laminate in which two or more woven fabrics are laminated.
Furthermore, it is preferable that at least a part of the material S is a sheet in which a reinforcing fiber fabric is impregnated with a thermoplastic resin or a laminate in which two or more sheets are laminated.
Moreover, it is preferable that the material R is a dispersion in which a plurality of cut products obtained by cutting a tape-like base material in which a reinforcing fiber aligned in one direction is impregnated with a thermoplastic resin are dispersed.
Furthermore, it is preferable that the shell portion is composed of only the material S.
In addition, the shell portion forms an open cross-sectional shape with a concave portion and edges provided on both sides of the concave portion, and a material including reinforcing fibers having a short fiber length is disposed at least on the inner surface of the edge portion. It is preferable.
The method for producing a fiber-reinforced thermoplastic resin molded article of the present invention is a method for producing a fiber-reinforced thermoplastic resin molded article comprising a shell portion having an open cross-sectional shape and a rib portion provided inside the shell portion. In the manufacturing method, the material R is laminated with a shell part constituent material including at least a material S having a higher bending elastic modulus than the material R constituting the rib part, and the material R is placed on a mold having a rib shape. Is arranged so as to be on the rib side and press-molded, and a shell portion including the material S and a rib portion composed of the material R are simultaneously molded.
The method for producing a fiber-reinforced thermoplastic resin molded article of the present invention contains a thermoplastic resin or a reinforcing fiber inside the shell portion after the shell portion is molded so that the cross section has an open cross-sectional shape. A method for producing a fiber-reinforced thermoplastic resin molded article in which a thermoplastic resin is injection-molded to form a rib part, and is an injection-molded product of a thermoplastic resin or a thermoplastic resin containing a reinforced fiber constituting the rib part. The shell portion is formed using at least a material S having a higher flexural modulus than that of the shell portion.

The composite of the present invention is characterized in that a plurality of the fiber-reinforced thermoplastic resin molded products are joined with the rib portions inside to form a closed cross-sectional shape.
Further, the method for producing a composite of the present invention is a method for producing a composite in which a plurality of the fiber reinforced thermoplastic resin molded articles are joined so that the rib portion is on the inside and the cross section is a closed cross section. And the said joining is made | formed by the vibration welding method, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the fiber reinforced thermoplastic resin molded article suitable as a composite material which shows a high mechanical characteristic, its manufacturing method, and the composite which shows a high mechanical characteristic, and its manufacturing method can be provided.

It is a perspective view which shows an example of the fiber reinforced thermoplastic resin molded product of this invention. It is a longitudinal cross-sectional view of the fiber reinforced thermoplastic resin molded product of FIG. It is a longitudinal cross-sectional view which shows the other example of a fiber reinforced thermoplastic resin molded product. It is a longitudinal cross-sectional view which shows the other example of a fiber reinforced thermoplastic resin molded product. It is a longitudinal cross-sectional view which shows the other example of a fiber reinforced thermoplastic resin molded product. (A) is a perspective view which shows typically the random sheet used as material R, (b) is a longitudinal cross-sectional view of the random sheet of (a). It is a perspective view which shows an example of the composite_body | complex of this invention. (A) is a perspective view which shows typically the orthogonal laminated body produced in Example 1, (b) is a longitudinal cross-sectional view of the orthogonal laminated body of (a). 1 is a longitudinal sectional view schematically showing a hybrid material produced in Example 1. FIG. It is a longitudinal cross-sectional view which illustrates typically arrangement | positioning of material R3 and the hybrid material at the time of manufacturing a molded article in Example 1. FIG. 6 is a longitudinal sectional view schematically showing a hybrid material produced in Example 2. FIG. It is a longitudinal cross-sectional view which illustrates typically arrangement | positioning of material R3 and the hybrid material at the time of manufacturing a molded article in Example 2. FIG.

Hereinafter, the present invention will be described in detail.
[Fiber-reinforced thermoplastic resin molded product]
FIG. 1 is a perspective view showing an example of a fiber-reinforced thermoplastic resin molded product (hereinafter simply referred to as “molded product”) of the present invention, and FIG. 2 is a longitudinal sectional view of the molded product of FIG.
2 to 5 and 7, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof may be omitted.

The molded product 10 shown in FIGS. 1 and 2 includes a shell portion 20 whose cross section is an open cross-sectional shape, and a rib portion 30 provided inside the shell portion 20.
The shell portion 20 is a portion corresponding to the outer layer portion of the molded product 10, and the shell portion 20 in this example includes a concave portion 21 along the longitudinal direction and an edge portion having a constant width formed along the longitudinal direction on both sides thereof. 22 form an open cross-sectional shape.
On the other hand, the rib portion 30 serves to reinforce the molded product 10 and prevent warping, and the rib portion 30 in this example is formed in a lattice shape as shown in FIG.
The shape of the shell portion 20 is not limited to the shape shown in FIGS. 1 and 2 as long as the cross section is an open cross section. Further, the shape of the rib portion 30 is not limited to the lattice shape as shown in FIG. 1 as long as it can play a role of reinforcement and warpage prevention.

The shell portion 20 includes a material S having a higher bending elastic modulus than the material R constituting the rib portion 30.
In the present invention, the flexural modulus is a value measured by a universal testing machine.
By the way, the bending elastic modulus of the material is one value in the case of an isotropic material, but particularly in the case of a material in which a reinforced fiber is impregnated with a thermoplastic resin, the bending elastic modulus depends on the laminated structure of the fiber and the bending test direction. Indicates anisotropy. In the present invention, when the material constituting the shell portion 20 and the rib portion 30 is a material in which a reinforcing fiber is impregnated with a thermoplastic resin, the highest bending elastic modulus is defined as the bending elastic modulus of the material.

As the material S, a fiber reinforced thermoplastic resin in which a reinforced fiber is impregnated with a thermoplastic resin is used. The reinforcing fiber constituting the fiber-reinforced thermoplastic resin may be a discontinuous fiber or a continuous fiber, but is preferably a continuous fiber. By using continuous fibers as the reinforcing fibers of the material S, compared to the case of discontinuous fibers, the molded product 10 and a composite obtained by joining a plurality of molded products 10 will be described in detail later. Excellent physical properties can be given.
The fiber length of the reinforcing fiber of the material S is preferably longer than the fiber length of the reinforcing fiber of the material R described later. By making the fiber length of the reinforcing fiber of the material S longer than the fiber length of the reinforcing fiber of the material R, the bending elastic modulus of the material S can be made larger than the bending elastic modulus of the material R. More excellent physical properties can be given to the composite.

  When the reinforcing fiber constituting the fiber-reinforced thermoplastic resin is a discontinuous fiber, the material S is a material in which the reinforcing fibers are dispersed in the thermoplastic resin in a state of being opened one by one; in the thermoplastic resin Examples include a bundle of reinforcing fibers dispersed. In particular, it is preferable that a plurality of cut pieces obtained by cutting a tape-like base material (fiber reinforced thermoplastic resin) in which a reinforcing fiber is impregnated with a thermoplastic resin are isotropically or pseudo-isotropically dispersed. By using a tape-like base material (fiber reinforced thermoplastic resin) in which a reinforced fiber is impregnated with a thermoplastic resin as the material S, the mechanical strength of the shell portion 20 can be increased.

On the other hand, when the reinforcing fiber constituting the fiber reinforced thermoplastic resin is a continuous fiber, the material S includes a tape-like or sheet-like base material in which a reinforcing fiber aligned in one direction is impregnated with a thermoplastic resin, or Laminate in which two or more substrates are laminated; woven fabric made of tape in which thermoplastic fibers are impregnated with reinforced fibers aligned in one direction, or laminate in which two or more woven fabrics are laminated; thermoplastic resin in reinforced fiber fabric Or a laminate in which two or more sheets are laminated.
Examples of the laminate include a unidirectional material in which the directions of the reinforcing fibers are the same in all layers, and an orthogonal laminated body in which the directions of the reinforcing fibers are orthogonal in each layer. Moreover, you may laminate | stack each layer so that the direction of the reinforced fiber of each layer may become an arbitrary angle.
On the other hand, examples of the woven fabric include plain weave, twill weave, satin weave, and triaxial weave.

The volume content of the reinforcing fibers in the material S (measured according to JIS K 7052) is preferably 10 to 60%.
When the volume content of the reinforcing fibers is 10% or more, excellent physical properties can be imparted to the molded article 10 and the composite described later. On the other hand, when the volume content of the reinforcing fibers is 60% or less, the shell portion 20 is easily formed when the shell portion 20 is formed by a method such as a press molding method.

The shell portion 20 only needs to contain at least the material S, and may be composed of only the material S (that is, only the layer 23 made of the material S) as shown in FIG. You may be comprised with other materials. Specifically, as shown in FIG. 3, the shell portion 20 has a two-layer structure, the layer 23 made of the material S is arranged on the outer side (the side where the rib portion 30 is not provided), and the layer 24 made of another material. May be arranged on the inner side (side on which the rib portion 30 is provided), or as shown in FIG. 4, a layer 23 made of material S is arranged between layers 24 made of other materials. Also good. Further, as shown in FIG. 5, the layer 23 made of the material S may be disposed on a part of the shell portion 20.
Although it does not restrict | limit especially as another material, Material R etc. are mentioned.

In addition, when using the molded article 10, although mentioned later in detail, the some molded article 10 may be joined by the vibration welding method etc., and it may be used for various uses as a composite_body | complex. When joining the some molded article 10, the inner surface (surface to be joined) 22a of the edge part 22 is joined so that the rib part 30 may become inside.
When a plurality of molded products 10 are joined and used in this way, the shell portion 20 is composed of the material S and another material as shown in FIGS. 3 to 5, and is formed on the inner surface 22 a of the edge portion 22. It is preferable that the fiber length of the existing reinforcing fiber is short. When the fiber length of the reinforcing fiber existing on the inner surface 22a is short, the plurality of molded articles 10 are easily welded. The reason is considered that in the case of a welding method such as vibration welding or ultrasonic welding, the fibers on the inner surface 22a are entangled well and high adhesive strength is obtained. In particular, on the inner surface 22a, it is preferable that reinforcing fibers having a short fiber length are isotropically or pseudo-isotropically dispersed in the thermoplastic resin. If the reinforcing fibers are isotropically or quasi-isotropically dispersed in the thermoplastic resin, they are easily welded when the plurality of molded articles 10 are joined.
Here, “the fiber length of the reinforcing fiber existing on the inner surface is short” means that the fiber length of the reinforcing fiber in the material S is shorter. Specifically, the number average is preferably 0.2 to 100 mm.

Therefore, in consideration of joining a plurality of molded articles 10, it is preferable that the fiber length of the reinforcing fiber existing on the inner surface 22a of the edge 22 is shorter than the fiber length of the reinforcing fiber in the material S. As shown to 3-5, it is especially preferable that the material containing the reinforced fiber with a short fiber length is arrange | positioned at least to the inner surface 22a as another material.
Further, from the viewpoint of improving the mechanical strength of the molded article 10 and the composite described later, it is preferable that the shell portion 20 is composed of only the material S as shown in FIG.

  On the other hand, as the material R constituting the rib portion 30, a thermoplastic resin or a fiber reinforced thermoplastic resin is used. In view of imparting excellent mechanical strength to the rib portion 30, the material R is preferably a fiber reinforced thermoplastic resin.

When a thermoplastic resin is used as the material R, a reinforcing agent such as an inorganic filler may be contained. Further, when a fiber reinforced thermoplastic resin is used as the material R, the material R is a material in which the reinforcing fibers are dispersed in the state of being opened one by one in the thermoplastic resin; a bundle of reinforcing fibers is formed in the thermoplastic resin. Examples are dispersed. In particular, a plurality of cut pieces obtained by cutting a tape-shaped base material (fiber reinforced thermoplastic resin) in which reinforced fibers aligned in one direction are impregnated with thermoplastic resin are isotropically or pseudo-isotropically dispersed. (Dispersion) is preferable, and among them, as shown in FIG. 6, a random sheet 40 in which a plurality of cut pieces 41 obtained by cutting a tape-like base material are dispersed pseudo-isotropically is preferable. 6A is a perspective view of the random sheet (dispersion), and FIG. 6B is a longitudinal sectional view of the random sheet of FIG.
By using the dispersion described above as the material R, the mechanical strength of the rib portion 30 can be increased.

  When a fiber reinforced thermoplastic resin is used as the material R, the fiber length (reinforced fiber length) of the reinforced fiber constituting the fiber reinforced thermoplastic resin is preferably shorter than the fiber length of the reinforced fiber of the material S. The number average is preferably 0.2 to 100 mm. When the reinforcing fiber length is 0.2 mm or more, the mechanical strength of the rib portion 30 is further improved. On the other hand, when the reinforcing fiber length is 100 mm or less, the fluidity of the material R is improved, and the rib portion 30 is easily formed when the rib portion 30 is formed by a method such as press molding or injection molding.

The volume content of the reinforcing fibers in the material R (measured according to JIS K 7052) is preferably 10 to 60%.
When the volume content of the reinforcing fiber is 10% or more, the mechanical strength of the rib portion 30 is further improved. On the other hand, when the volume content of the reinforcing fiber is 60% or less, the rib portion 30 is easily formed when the rib portion 30 is formed by a method such as press molding or injection molding.

Although it does not restrict | limit especially as a thermoplastic resin which can be used for the material S and the material R, For example, polyester, such as polyolefin, such as polyethylene and a polypropylene, a polyethylene terephthalate and a polybutylene terephthalate, polystyrene, ABS resin, an acrylic resin, vinyl chloride, polyamide 6 etc. And polyamides, polycarbonates, polyphenylene ethers, polyether sulfones, polysulfones, polyether imides, polyketones, polyether ketones, polyether ether ketones, and modified products and blends thereof. Further, the thermoplastic resin may contain an additive, a filler, a colorant, and the like.
On the other hand, examples of the reinforcing fiber that can be used for the material S and the material R include glass fiber, carbon fiber, and aramid fiber.

In the material S and the material R, the reinforcing fiber and the thermoplastic resin constituting the fiber reinforced thermoplastic resin may be of the same type as long as the bending elastic modulus of the material S is higher than the bending elastic modulus of the material R. Different types may be used.
When the reinforcing fiber and the thermoplastic resin are of the same type, the fiber length of the reinforcing fiber of the material S is changed to the fiber length of the reinforcing fiber of the material R as a method for making the bending elastic modulus of the material S larger than the bending elastic modulus of the material R. And a method of making the reinforcing fiber content of the material S larger than the reinforcing fiber content of the material R. In the material S, a reinforcing fiber or a thermoplastic resin having a larger elastic modulus than that of the reinforcing fiber or the thermoplastic resin used in the material R may be used.
In addition, if the fiber length of the reinforcing fiber of the material R is shorter than the fiber length of the reinforcing fiber of the material S, for example, as shown in FIGS. 3 to 5, it is disposed at least on the inner surface 22 a of the edge portion 22 of the shell portion 20. The material R is also suitable as another material.

The molded article 10 as shown in FIG. 1 can be manufactured as follows, for example.
First, a plate-like material S is produced. Specifically, a bundle-like continuous fiber composed of a large number of reinforcing fiber filaments is prepared as the reinforcing fiber, and after opening the fiber, the fiber bundle is impregnated with a thermoplastic resin to form a tape-like or sheet-like substrate. A woven fabric (prepreg) made of material or tape is obtained. Since the thickness of the prepreg is appropriately set according to the intended use and the intended physical properties, a laminate obtained by laminating two or more substrates or fabrics so as to have a desired thickness may be used as the prepreg.
Next, the prepreg (plate-like material S) is preheated by a heating means such as an infrared heating furnace, and then placed on a die having no rib shape, and press-molded so that the cross-section becomes an open cross-sectional shape. The part 20 is molded.
Next, a thermoplastic resin or a thermoplastic resin containing reinforcing fibers is injection-molded inside the shell portion 20 to form the rib portion 30, and the molded product 10 is obtained.

The manufacturing method of the molded article 10 is not limited to the method described above.
In the above-described method, continuous fibers are used as the reinforcing fibers contained in the material S. For example, discontinuous reinforcing fibers are dispersed in a thermoplastic resin in a state of being opened or bundled one by one. Alternatively, a random sheet 40 in which a cut product 41 obtained by cutting a non-fiber reinforced thermoplastic resin as illustrated in FIG. 6 is pseudo-isotropically dispersed may be used as the plate-shaped material S (prepreg).
For example, as shown in FIGS. 3 to 5, when manufacturing the molded product 10 in which the shell portion 20 is composed of the material S and other materials, the plate-shaped material S (prepreg) and other materials are used. The shell part constituent material may be produced by laminating, and the shell part 20 may be formed using the shell part constituent material.

In the above-described method, the rib portion 30 is formed after the shell portion 20 is formed. For example, the shell portion 20 and the rib portion 30 are simultaneously formed by the following method to form the molded product 10. It may be manufactured.
First, the plate-shaped material S is produced by the method described above.
Separately, a plate-like material R is produced. Specifically, a bundle-like continuous fiber composed of a large number of reinforcing fiber filaments is prepared as the reinforcing fiber, and after opening the fiber, the fiber bundle is impregnated with a thermoplastic resin to form a tape. A random sheet 40 (plate-shaped material R) as shown in FIG. 6 is heated, pressurized and cooled in a mold in a state in which a plurality of the obtained cut pieces are randomly dispersed. Get.
Next, after laminating the plate-like material R and the material S and preheating them with heating means such as an infrared heating furnace, the material R is placed on a rib-shaped mold so that the material R is on the rib side and press-molded. Then, the molded product 10 is obtained, or the plate-like material R and the material S are separately preheated by heating means such as an infrared heating furnace, and then the material R is placed on the rib side on the rib-shaped mold. Thus, the material R and the material S are laminated and arranged, and press-molded to obtain a molded product 10.

  For example, as shown in FIGS. 3 to 5, when manufacturing the molded product 10 in which the shell portion 20 is composed of the material S and another material, the material portion S and another material are laminated in advance to form the shell portion. A material is prepared, the shell constituent material and the material R (rib part constituent material) are laminated, preheated by heating means such as an infrared heating furnace, and then the material R is placed on a mold having a rib shape. The shell part 20 and the rib part 30 may be formed at the same time by placing the rib part constituent material on the rib side and performing press molding.

  Furthermore, after preheating the plate-shaped material R with a heating means such as an infrared heating furnace, the plate-shaped material R may be put on a die having a rib shape and press-molded, and then the plate-shaped material S may be bonded to form a molded product 10. .

As described above, in the molded product of the present invention, the shell portion includes the material S having a higher bending elastic modulus than the material R constituting the rib portion provided inside the shell portion. Has high mechanical strength. Moreover, since the bending elastic modulus of the material R which comprises a rib part means that the material R has moderate fluidity | liquidity, the rib part of arbitrary shapes is easily shape | molded inside a shell part. be able to. Therefore, since the shell portion can be reinforced by the rib portion, the molded article of the present invention exhibits high mechanical characteristics as a whole.
If the rib portion is also made of a material having a high bending elastic modulus, such as the material S, the mechanical strength of the molded product is considered to be higher, but a material having a high bending elastic modulus is poor in fluidity. A rib portion having a more complicated shape than the shell portion cannot be formed.

However, according to the present invention, the rib portion is made of the material R having a low bending elastic modulus, and the material S having a higher bending elastic modulus than the material R is included in the shell portion. Easy to obtain. In particular, if the fiber length of the reinforcing fiber of the material R is shorter than the fiber length of the reinforcing fiber of the material S, the bending elastic modulus of the material S tends to be higher than the bending elastic modulus of the material R, and the flow of the material R Therefore, a molded product exhibiting high mechanical properties can be obtained more easily.
The molded product of the present invention is suitable as a composite material formed by integrating a plurality of molded products.
In the present invention, “high mechanical properties” means that the initial gradient of the load displacement curve is high in the destructive test, that is, the maximum amount of displacement until a certain load is applied, It means that the load value is high.

[Complex]
FIG. 7 is a perspective view showing an example of the composite of the present invention.
In the composite 50 shown in FIG. 7, the above-described molded products 10 and 10 of the present invention are joined with the rib portions 30 and 30 inside, forming a closed cross-sectional shape. The molded products 10 and 10 in this example have the same size and shape, and are arranged so that the concave portions 21 and 21 and the edge portions 22 and 22 face each other, and then the opposite edge portions. The inner surfaces (bonded surfaces) 22a and 22a of 22 and 22 are joined together by vibration welding to form a closed cross-sectional shape.

The composite 50 shown in FIG. 7 can be manufactured, for example, as follows.
Two molded products 10 are prepared, and these are arranged so that the recessed portions 21 and 21 face each other and the edge portions 22 and 22 face each other and form a closed cross-sectional shape, and the inner surfaces of the facing edge portions 22 and 22 ( Joined by vibration welding method so that the joined surfaces 22a and 22a are joined together. The vibration welding method is a method of joining by vibrating the inner surfaces 22a and 22a in contact with each other, and can be performed by a commercially available vibration welding machine.

The manufacturing method of the composite 50 is not limited to the method described above.
In the above-described method, the vibration welding method is exemplified as the method for joining the molded products 10 and 10, but for example, a hot plate welding method, a resistance welding method, an ultrasonic welding method, or the like may be employed. However, among these, the vibration welding method is preferable because it can join the molded articles better than other welding methods.

  In the above-described method, the composite 50 to be manufactured is exemplified by a closed cross-sectional shape in which two molded products 10 and 10 having the same shape are joined, but the number of molded products may be three or more, The molded products to be joined may have different shapes.

  Furthermore, it is preferable that the same kind of thermoplastic resin is used for the molded products to be joined together. However, in each molded product 10, the shell portion 20 is more suitable than the material R of the rib portion 30. Different types of thermoplastic resins may be used as long as they include the material S having a high flexural modulus and there is no problem with the bondability. Moreover, although the same kind of reinforcing fiber is normally used for the molded articles to be joined, different kinds of reinforcing fibers may be used depending on the purpose.

  As described above, the composite of the present invention is formed by joining a plurality of the molded products of the present invention described above, and thus exhibits high mechanical properties as a whole.

  Such composites include, for example, automotive parts such as front subframes, rear subframes, front pillars, center pillars, side members, cross members, side sills, roof rails, propeller shafts, pipes for submarine oil fields, electric wire cable cores, etc. It is suitably used for roll pipes for printing presses, robot forks, primary structural materials for aircraft, secondary structural materials, and the like.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Example 1]
<Manufacture of fiber-reinforced thermoplastic resin molded products>
(Production of material R)
Carbon fibers (manufactured by Mitsubishi Rayon Co., “TR50S”) were used as continuous reinforcing fibers. This carbon fiber is a bundle of 12,000 filaments each having a diameter of about 7 μm.
The carbon fiber bundle was opened and impregnated with maleic anhydride-modified polypropylene as a thermoplastic resin, and a continuous carbon fiber reinforced thermoplastic resin tape having a volume content of reinforcing fibers of 50%, a width of 12 mm, and a thickness of 100 μm was prepared. .

The continuous carbon fiber reinforced thermoplastic resin tape was cut into 30 mm, and this was randomly dispersed in a plane on a flat plate mold and deposited so as to have a predetermined thickness. A material R1 having a thickness of about 1.5 mm as shown in FIGS. 6 (a) and 6 (b) is formed by heating and pressure molding at a molding temperature of 220 ° C., a molding pressure of 1.0 MPa, and a holding time of 10 minutes. Got.
Similarly, a material R2 having a thickness of about 2.7 mm and a material R3 having a thickness of about 4 mm were obtained.
About these materials R1-R3, when the bending elastic modulus was measured using the universal testing machine (Shimadzu Corp. make, "AG-X"), all were 25 GPa.

(Production of material S)
In the same manner as the material R, a continuous carbon fiber reinforced thermoplastic resin tape was prepared.
The continuous carbon fiber reinforced thermoplastic resin tape is arranged and arranged at regular intervals so as to form a layer having a fiber basis weight of 180 g / m ² and a thickness of about 0.2 mm, and then a molding temperature of 190 ° C. and a molding pressure of 0.1 MPa. Then, after heating and pressing with a holding time of 5 minutes and cooling the mold, a layer (material S) in which the fibers were oriented in one direction was obtained.
With respect to the obtained material S, the bending elastic modulus in the fiber direction was measured using a universal testing machine (manufactured by Shimadzu Corporation, “AG-X”).

(Manufacture of fiber-reinforced thermoplastic resin molded products)
Five sheets of the material S prepared earlier were prepared, and an orthogonal laminated body having a thickness of about 1 mm as shown in FIGS. 8A and 8B (0 ° when the long direction of the material S was taken as the 0 ° direction) / 90 ° / 0 ° / 90 ° / 0 °). In addition, the code | symbol 60 in FIG. 8 is an "orthogonal laminated body", and the code | symbol 61 is "material S".
As shown in FIG. 9, this orthogonal laminate is combined with two pieces of the material R1 having a thickness of about 1.5 mm, which are produced in advance, and the molding temperature is 190 ° C., the molding pressure is 0.1 MPa, and the holding time is 5 minutes. In addition, a shell constituent material 1 (hybrid material 1) having a thickness of about 4 mm in which the material S was disposed on one surface and the material R1 was disposed on the other surface was obtained. In addition, the code | symbol 60 in FIG. 9 is an "orthogonal laminated body", the code | symbol 70 is the "shell part constituent material 1", and the code | symbol 71 is "material R1."

  The obtained shell portion constituting material 1 having a thickness of 4 mm and the material R3 having a thickness of about 4 mm prepared previously were placed in an infrared heater (manufactured by NGK Co., Ltd.) heated to 270 ° C. for 5 minutes. The shell constituent material 1 and the material R3 are taken out from the infrared heater, and as shown in FIG. 10, the material R3 and the shell constituent material 1 are made into a lower mold having a grid-like rib shape so that the material R3 is on the lower side. Placed on top. These were molded under the conditions of an upper mold temperature of 130 ° C., a lower mold temperature of 130 ° C., a molding pressure of 30 MPa, and a holding time of 1 minute. By this molding, a molded product 10 was obtained in which the grid-like rib portions 30 as shown in FIG. 1 were provided inside the shell portion 20 having an open cross-sectional shape. In addition, the code | symbol 60 in FIG. 10 is an "orthogonal laminated body", the code | symbol 70 is the "shell part constituent material 1", the code | symbol 71 is "material R1", and the code | symbol 72 is "material R3".

<Manufacture of composite>
Two molded products 10 manufactured previously were prepared, and these were arranged so that the concave portions 21 and 21 and the edge portions 22 and 22 faced each other to form a closed cross-sectional shape. Then, using a vibration welding machine (manufactured by Nippon Emerson Co., Ltd.), the inner surfaces 22a and 22a of the facing edges 22 and 22 are vibrated in contact with each other, and the resins of the inner surfaces 22a and 22a are joined (welded). As shown in FIG. 7, two molded products 10 and 10 were joined with the rib portions 30 and 30 inside, and a composite 50 having a closed cross-sectional shape was obtained. The joining was performed under the conditions of a load of 15 kN and an amplitude of 1.5 mm, and the vibration was stopped when the thickness of the joined portion (total thickness of the edges 22 and 22) was reduced by 0.5 mm.
Even if it tried to isolate | separate the composite 50 after joining by hand, it was not able to isolate | separate but the integral shape was maintained.

<Evaluation>
The mass of the obtained composite was measured.
Further, the composite was subjected to a three-point bending test using a universal testing machine (manufactured by Shimadzu Corporation, “AG-X”). The test conditions were: load cell: 50 kN, span length: 350 mm, test speed: 5 mm / min, indenter diameter: R75, support diameter: R15.
The three-point bending test was performed until the displacement amount of the universal testing machine reached 50 mm, and the maximum load value during that time was measured. The results are shown in Table 1.
Further, the displacement amount at a load of 3000 N was measured as a value indicating the rigidity of the composite. This value is shown in Table 1 as 3 kN displacement.
Moreover, the maximum load [N / g] per unit mass was calculated | required from following formula (1). The results are shown in Table 1.
Maximum load per unit mass = Maximum load / Mass of composite (1)

Moreover, the average of the gradient from the load 0N to the load 3000N of the load-displacement curve obtained by the previous three-point bending test is obtained from the following formula (2), and this value is shown in Table 1 as the 0-3 kN average gradient. .
0-3kN average gradient = displacement at 3000N / 3000N (2)

Moreover, the average gradient per unit mass was calculated | required from following formula (3). The results are shown in Table 1.
Average gradient per unit mass = 0-3 kN average gradient / mass of complex (3)

[Example 2]
As shown in FIG. 11, a shell part constituent material 2 (hybrid material 2) was produced under the same conditions as in Example 1 except that the orthogonal laminate was sandwiched between two materials R1. In addition, the code | symbol 60 in FIG. 11 is an "orthogonal laminated body", the code | symbol 71 is "material R1", and the code | symbol 80 is "shell part constituent material 2".
Except for the arrangement pattern of the shell part constituting material 2 and the material R3 as shown in FIG. 12, a molded article and a composite were produced in the same manner as in Example 1, and a three-point bending test was performed. The results are shown in Table 1. In FIG. 12, reference numeral 60 is an “orthogonal laminate”, reference numeral 71 is “material R1”, reference numeral 72 is “material R3”, and reference numeral 80 is “shell component material 2”.

[Comparative Example 1]
Molding is performed in the same manner as in Example 1 except that the material R2 having a thickness of 2.7 mm is used instead of the shell constituent material 1 and a die having no rib shape inside is used. Articles and composites were manufactured and a three-point bending test was performed. The results are shown in Table 1.

[Comparative Example 2]
A molded product and a composite were produced in the same manner as in Example 1 except that the material R3 having a thickness of 4 mm was used instead of the shell constituent material 1 in the production of the molded product, and a three-point bending test was performed. The results are shown in Table 1.

[Comparative Example 3]
In the production of a molded product, a molded product was obtained in the same manner as in Example 1 except that a material R2 having a thickness of 2.7 mm was used instead of the material R3 having a thickness of 4 mm and a die having no rib shape inside was used. And composites were manufactured and a three point bend test was performed. The results are shown in Table 1.

As is clear from Table 1, the composites obtained in Examples 1 and 2 had a maximum load of 11 kN or more per unit mass in the three-point bending test, compared with the composites obtained in Comparative Examples 1 to 3. Machine with a maximum load of 30.6 N / g or more, an average gradient of 0-3 kN of 3000 N / mm or more, an average gradient per unit mass of 8.3 or more, and a low 3 kN displacement of 1.0 mm or less. The characteristic was shown.
On the other hand, the composites obtained in Comparative Examples 1 to 3 were inferior in mechanical properties as compared to the composites obtained in Examples 1 and 2.

DESCRIPTION OF SYMBOLS 10 Fiber reinforced thermoplastic resin molded product 20 Shell part 21 Concave part 22 Edge part 22a Inner surface 30 Rib part 50 Composite 61 Material S
70 Shell component material 1
71 Material R1
72 Material R3
80 Shell component material 2

Claims (11)

A fiber-reinforced thermoplastic resin molded article comprising a shell portion having a cross-sectional open section shape and a rib portion provided inside the shell portion,
The fiber-reinforced thermoplastic resin molded article, wherein the shell portion includes a material S having a higher bending elastic modulus than the material R constituting the rib portion.   At least a part of the material S is a tape-like or sheet-like base material obtained by impregnating a thermoplastic resin with reinforcing fibers aligned in one direction, or a laminate in which two or more base materials are laminated. The fiber-reinforced thermoplastic resin molded article according to claim 1.   2. At least a part of the material S is a woven fabric made of a tape in which a reinforced fiber aligned in one direction is impregnated with a thermoplastic resin, or a laminate in which two or more woven fabrics are laminated. The fiber-reinforced thermoplastic resin molded article described in 1.   2. The fiber-reinforced thermoplastic resin according to claim 1, wherein at least a part of the material S is a sheet in which a reinforced fiber fabric is impregnated with a thermoplastic resin or a laminate in which two or more sheets are laminated. Molding.   5. The material R according to claim 1, wherein the material R is a dispersion in which a plurality of cut pieces obtained by cutting a tape-like base material impregnated with a thermoplastic resin in reinforcing fibers aligned in one direction are dispersed. The fiber-reinforced thermoplastic resin molded article according to any one of the above.   The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 5, wherein the shell portion is composed of only the material S.   The shell portion forms an open cross-sectional shape with a concave portion and edges provided on both sides of the concave portion, and a material including reinforcing fibers having a short fiber length is disposed at least on the inner surface of the edge. The fiber-reinforced thermoplastic resin molded article according to any one of claims 1 to 5. A method for producing a fiber-reinforced thermoplastic resin molded article comprising a shell part having an open cross-sectional shape and a rib part provided inside the shell part,
A shell part constituent material including at least a material S having a higher bending elastic modulus than the material R constituting the rib part, and the material R are laminated so that the material R is on the rib side in a mold having a rib shape. A method for producing a fiber-reinforced thermoplastic resin molded article, wherein the shell part including the material S and the rib part composed of the material R are simultaneously molded by being placed and press-molded. Fiber-reinforced thermoplastic that forms a rib part by injection molding a thermoplastic resin or a thermoplastic resin containing reinforcing fiber inside the shell part after molding the shell part so that the cross-section becomes an open cross-sectional shape A method for producing a resin molded product, comprising:
Fiber reinforced, wherein the shell portion is molded using at least a material S having a higher flexural modulus than that of an injection molded product of a thermoplastic resin or a thermoplastic resin containing a reinforcing fiber constituting the rib portion. A method for producing a thermoplastic resin molded article.   A composite comprising a plurality of the fiber-reinforced thermoplastic resin molded products according to any one of claims 1 to 7 joined together with a rib portion on an inside to form a closed cross-sectional shape. The manufacturing method of the composite_body | complex which joins two or more of the fiber reinforced thermoplastic resin molded products as described in any one of Claims 1-7 so that a rib part may become an inner side and a cross section may become a closed cross-sectional shape. Because
The joining is performed by a vibration welding method.

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