JP2023130580A - Method for manufacturing molded products using fiber-reinforced thermoplastic resin composite material - Google Patents

Abstract

To provide a molded product using a fiber-reinforced thermoplastic resin composite material made of continuous fibers, which are capable of producing products with excellent strength.SOLUTION: A method for manufacturing a fiber-reinforced thermoplastic resin composite material 100 comprising a base 101 and ribs 102 protruding from the base 101, includes: a composite material preparation step of preparing the continuous fiber thermoplastic resin composite material 100 in which a continuous fiber sheet 100a made of continuous fibers is impregnated with a thermoplastic resin R and is solidified; and a forming step of heating and press-molding the base 101 made of the continuous fiber thermoplastic resin composite material 100 and plastically deforming a part of the base 101 into a protruding shape to form the ribs 102.SELECTED DRAWING: Figure 1

Description

The present invention relates to a molded article using a fiber-reinforced thermoplastic resin composite material and a method for manufacturing the same.

In recent years, fiber-reinforced resins obtained by impregnating thermoplastic resins with reinforcing fiber materials such as carbon fibers and glass fibers have been widely used in various fields, such as automobiles that require high mechanical properties, Used in the housings of home appliances, etc.

In such a fiber-reinforced thermoplastic resin composite material, a carbon fiber-reinforced thermoplastic resin layer in which a plurality of short fiber bundles (also referred to as "chopped materials") are randomly oriented and integrated in advance with a thermoplastic resin is used. is provided on at least one surface of the non-reinforced thermoplastic resin layer to form a laminate, and the laminate is heated and pressed to form protruding ribs on the sheet-like base. A method of manufacturing a molded article using a fiber-reinforced thermoplastic resin composite material is known (for example, see Patent Document 1).

JP2020-049925A

However, in the method for producing a molded article described in Patent Document 1, the short fiber bundles are randomly oriented and the thickness of the short fiber bundles varies, so there is a problem that the strength is poor. be.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a molded article using a fiber-reinforced thermoplastic resin composite material that can produce a product with excellent strength.

In order to solve the above object, the invention according to claim 1 is a method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite material comprising a base and a rib protruding from the base,
a composite material preparation step of preparing a continuous fiber thermoplastic resin composite material in which a continuous fiber sheet made of continuous fibers is impregnated with a thermoplastic resin and then solidified;
a molding step of hot press molding the base made of the continuous fiber thermoplastic resin composite material, and plastically deforming a part of the base into a projecting shape including the continuous fibers to form the ribs. Features.

The invention according to claim 2 is a method for manufacturing a molded article using the fiber-reinforced thermoplastic resin composite material according to claim 1, comprising:
In the molding step, the continuous fiber thermoplastic resin composite material is heated at 160° C. or higher.

The invention according to claim 3 is a method for manufacturing a molded article using the fiber-reinforced thermoplastic resin composite material according to claim 1, comprising:
In the molding step, the continuous fiber thermoplastic resin composite material is heated at 200° C. or higher.

The invention according to claim 4 is a method for manufacturing a molded article using the fiber-reinforced thermoplastic resin composite material according to any one of claims 1 to 3,
In the molding step, the continuous fiber thermoplastic resin composite material is pressed at a pressure of 10 tons or more.

The invention according to claim 5 is a molded article using a fiber-reinforced thermoplastic resin composite material containing continuous fibers and a thermoplastic resin,
The base part and
a rib portion protruding from the base and extending in at least one direction;
At least some of the fiber bundles included in the continuous fibers have a plurality of inflection points, and a curved portion is formed to curve from the base portion to return to the base portion via the rib portion. The ribs are coated with the thermoplastic resin and are distributed continuously in the extending direction of the rib portion.

The invention according to claim 6 provides a molded article using the fiber-reinforced thermoplastic resin composite material according to claim 5,
It is characterized in that the continuous fibers in the rib portion are layered.

The invention according to claim 7 provides a molded article using the fiber-reinforced thermoplastic resin composite material according to claim 5 or 6,
The content ratio of the continuous fibers in the rib portion is higher than the content ratio of the continuous fibers in the base portion.

According to the present invention, it is possible to provide a molded article using a fiber-reinforced thermoplastic resin composite material that can produce a product with excellent strength.

It is a figure explaining an example of the manufacturing method of the molded article using the fiber reinforced thermoplastic resin composite material concerning this embodiment. (A) is a front view of a sample molded according to the present embodiment, and (B) is a sectional view taken along the line AA shown in (A). FIG. 3 is an enlarged cross-sectional view of a molded product illustrating the finish when ribs are formed under different press working conditions.

EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing method of the molded article using the fiber reinforced thermoplastic resin composite material based on embodiment of this invention is demonstrated with reference to drawings. However, the scope of the invention is not limited to the illustrated example. In the following description, parts having the same functions and configurations will be denoted by the same reference numerals, and the description thereof will be omitted.

<Method for manufacturing continuous carbon fiber thermoplastic resin composite material>
An example of a method for manufacturing the continuous carbon fiber thermoplastic resin composite material 100 according to the present embodiment will be described with reference to FIG. 1.

First, in this embodiment, as shown in FIG. 1(1), a continuous fiber portion 100a made of continuous carbon fiber is prepared. The continuous fiber portion 100a is not limited to carbon fibers, but may include inorganic fibers such as glass fibers and silicon carbide fibers, metal fibers such as boron fibers, and organic fibers such as aramid fibers. A combination of the above can be applied. These continuous fibers are expected to improve mechanical strength. Although the continuous fibers in this embodiment are composed of multiple layers, they may be composed of a single layer. As the layer thickness increases, the strength increases, but the material cost also increases accordingly. Therefore, in this embodiment, as described later, the strength is increased by forming a single layer of continuous fibers and forming ribs by hot pressing. I can do it. Needless to say, this embodiment does not negate the use of multiple layers of continuous fibers, and may be configured with multiple layers.

Subsequently, as shown in FIG. 1(2), the heated and melted thermoplastic resin R is injected into the container C, and the continuous fiber portion 100a is immersed in the container C into which the thermoplastic resin R is injected. is impregnated into the continuous fiber portion 100a. In this embodiment, thermoplastic polyurethane is used as the thermoplastic resin R, but other thermoplastic resins may be used, such as epoxy resin, polyamide, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, and Teflon. (registered trademark), ABS (acrylonitrile butadiene styrene), acrylic, polyamide, polyacetal, modified polyphenylene ether, polyester, cyclic polyolefin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer , polyetheretherketone, thermoplastic polyimide, polyamideimide, polyethylene terephthalate, polycarbonate, etc., or a mixture of two or more thereof may be used.

After immersing the continuous fiber portion 100a in the container C for a predetermined time, when the continuous fiber portion 100a is taken out, the continuous fiber portion 100a is impregnated with the melted thermoplastic resin R, and the resin portion is 100b, by which the continuous carbon fiber thermoplastic resin composite material 100 is molded. Thereafter, the resin portion 100b is cooled until solidified. Thus, in this embodiment, the steps shown in FIGS. 1(1) to 1(3) correspond to the composite material preparation step. Note that the continuous carbon fiber thermoplastic resin composite material 100 formed as described above may be obtained in advance by purchase, etc., and the composite material preparation step may be performed.

Thereafter, the continuous carbon fiber thermoplastic resin composite material 100 molded as described above is heated and pressed using a press machine 200. Specifically, as shown in FIG. 1(4), the press machine 200 includes a first mold 200a in which the continuous carbon fiber thermoplastic resin composite material 100 is installed, and an upper part of the first mold 200a. A second mold 200b is provided, which is disposed at , and presses the continuous carbon fiber thermoplastic resin composite material 100 together with the first mold 200a. Further, both the first mold 200a and the second mold 200b are heated. When hot pressing the continuous carbon fiber thermoplastic resin composite material 100 using the press machine 200 configured as described above, first, the continuous carbon fiber thermoplastic resin composite material 100 is pressed into the first press machine of the press machine 200. Then, the second mold 200b placed above the first mold 200a is moved downward, and the continuous carbon fiber thermoplastic resin composite material 100 is heated and pressed. I do. One or more concave rib forming portions 200c are formed at appropriate positions on the lower surface of the second mold 200b of the press 200 in this embodiment. In this embodiment, hot pressing is performed on the continuous carbon fiber thermoplastic resin composite material 100 at a predetermined temperature or higher and a predetermined pressure or higher for a predetermined time. Suitable heating temperatures and pressures will be described later.

Then, as shown in FIG. 1(5), the resin part 100b is plastically deformed together with the continuous fiber part 100a while being melted (that is, the base part 101 is plastically deformed), and is formed into the second mold 200b. The rib 102 is formed by entering the rib forming portion 200c. That is, when hot pressing is performed on the continuous carbon fiber thermoplastic resin composite material 100 using the first mold 200a and the second mold 200b, the resin portion 100b and the continuous fiber portion 100a are pressed into the second mold. The rib 102 is formed by moving to the rib forming portion 200c formed on the portion 200b. In this embodiment, the rib forming portion 200c of the second mold 200b is set so that the height of the rib 102 is approximately 2.5 mm and the width is 2 mm or more, and the heating temperature, press pressure, and heating Press time has been adjusted. If the width of the rib forming portion 200c is narrow relative to the height, it becomes difficult for the continuous fiber portion 100a to enter the rib forming portion 200c, so it is preferable to set the width appropriately.

Thereafter, after cooling and hardening the continuous carbon fiber thermoplastic resin composite material 100, when the continuous carbon fiber thermoplastic resin composite material 100 is taken out from the press machine 200, as shown in FIG. 1(6), one or more A molded article of the continuous carbon fiber thermoplastic resin composite material 100 is formed with the ribs 102 protruding from the base 101. Thus, in this embodiment, the steps shown in FIGS. 1(4) to 1(6) correspond to the molding step.

The molded product formed in this way has a structure in which at least some of the fiber bundles included in the continuous fiber portion 100a protrude into the ribs 102, as shown in FIGS. 3(b) and 3(c), for example. A curved portion that forms a plurality of inflection points and is curved from the base 101 to return to the base 101 via the rib 102 is covered with the resin portion 100b and is continuously distributed in the extending direction of the rib 102. formed to be At this time, the curved portion has a symmetrical distribution. Further, in the molded product molded as described above, the content ratio of the resin is higher in the ribs 102 than in the base 101. Therefore, compared to the conventional carbon fiber-reinforced thermoplastic resin layer in which multiple short fiber bundles (chopped material) are randomly oriented and integrated with thermoplastic resin in advance, the strength of the ribs is significantly increased, and continuous carbon The fibers are curved into the ribs, making them difficult to break.

Further, according to the present embodiment, by combining metal press molding technology and high temperature resin molding technology, and molding the ribs 102 at the same time as processing the continuous carbon fiber thermoplastic resin composite material 100, the resin portion 100b Since it is possible to mold a molded product in which the ribs 102 are continuously distributed in a layered manner from the base 101 to the ribs 102, including the continuous fiber portion 100a, the ribs 102 are fixed to the base 101. The ribs 102 are less likely to break than those added later, and stable and good strength can be obtained.

Additionally, compared to the conventional method of bonding multiple layers of thermosetting resin together and baking them to form a composite material, composite materials can be processed in a simpler manner and in a shorter time, resulting in superior manufacturing costs. , which is also advantageous for mass production.

The present invention will be explained in more detail with reference to the following examples, but the present invention is not limited to the following examples.

A carbon fiber thermoplastic resin composite material using continuous carbon fibers was heated and pressed under different molding conditions.

[Comparative example 2-1]
Continuous carbon fibers were impregnated with thermoplastic polyurethane and molded into CFRTP (Carbon Fiber Reinforced Thermo Plastics; fiber volume content (Vf) = 45%; manufactured by Sanwa Trading Co., Ltd.) to a thickness of approximately 1.0 mm. This CFRTP was cut into an appropriate size, and a predetermined mold was set in a press machine. The molds used include a first mold with a flat upper surface, a thin leaf part 301 (see Fig. 2) that has a leaf-like external shape of a broad-leaved tree, and a thin leaf part 301 in the longitudinal center of the upper surface of the thin leaf part 301. A first leaf vein part 302 (see FIG. 2) that extends and protrudes, and a plurality of leaf veins that protrude from the upper surface of the thin leaf part so as to protrude from the first leaf vein part 302 in the left-right direction, respectively. A second mold is provided in which a concave portion in which at least a second leaf vein portion 303 (see FIG. 2) is formed is formed on the pressing surface. Note that the first leaf vein portion 302 and the second leaf vein portion 302 function as ribs. A sample 300 molded under such conditions is shown in FIG.
The above CFRTP was set in the above press machine, and was heated to 100° C. and pressed at a pressure of 6 tons, aiming at the height of the first leaf vein portion and the second leaf vein portion to be approximately 2.5 mm.

[Comparative example 2-2]
The CFRTP molded according to Comparative Example 2-1 was set in a press machine, heated to 100°C and under a pressure of 8 tons, with the aim of making the height of the first and second vein parts about 2.5 mm. Press processing was performed.

[Comparative example 2-3]
The CFRTP molded according to Comparative Example 2-1 was set in a press machine, heated to 100°C and under a pressure of 10 tons, with the aim of making the height of the first and second vein parts about 2.5 mm. Press processing was performed.

[Example 2-1]
The CFRTP molded according to Comparative Example 2-1 was set in a press machine, heated to 160°C and under a pressure of 6 tons, with the aim of making the height of the first leaf vein part and the second leaf vein part about 2.5 mm. Press processing was performed.

[Example 2-2]
The CFRTP molded according to Comparative Example 2-1 was set in a press machine, heated to 160°C and under a pressure of 8 tons, with the aim of making the height of the first leaf vein part and the second leaf vein part about 2.5 mm. Press processing was performed.

[Example 2-3]
The CFRTP molded according to Comparative Example 2-1 was set in a press machine, heated to 160°C and under a pressure of 10 tons, with the aim of making the height of the first leaf vein part and the second leaf vein part about 2.5 mm. Press processing was performed.

[Example 2-4]
The CFRTP molded according to Comparative Example 2-1 was set in a press, heated to 200°C and under a pressure of 6 tons, with the aim of making the height of the first leaf vein part and the second leaf vein part about 2.5 mm. Press processing was performed.

[Example 2-5]
The CFRTP molded according to Comparative Example 2-1 was set in a press machine, heated to 200°C and under a pressure of 8 tons, with the aim of making the height of the first leaf vein part and the second leaf vein part about 2.5 mm. Press processing was performed.

[Example 2-6]
The CFRTP molded according to Comparative Example 2-1 was set in a press machine, heated to 200°C and under a pressure of 10 tons, aiming at the height of the first leaf vein part and the second leaf vein part to be about 2.5 mm. Press processing was performed.

The time during which pressure was applied to the molded products of carbon fiber thermoplastic resin composites obtained in Comparative Examples 2-1 to 2-3 and Examples 2-1 to 2-6, respectively (pressure time) A three-point bending test (distance between fulcrums = 40 mm, test speed = 5 mm/min) was conducted to determine the quality of the molding, and the strength of each molded product was measured. The results are shown in Table 1. In addition, the molded product obtained in Comparative Example 2-1 was cut and the cross section of the leaf vein part (rib part) was observed with a digital microscope as shown in Figure 3(A). The molded product obtained in Example 2-2 was cut and the cross section of the leaf vein part was observed with a digital microscope as shown in Figure 3(B). Figure 3(C) shows what was observed with the scope.

In all of Examples 2-1 to 2-6, a high maximum test force was obtained, and sufficient performance was obtained. In particular, it was found that in Examples 2-5 and 206, the leaf veins were formed in a shorter pressure time than in the other Examples. According to these Examples 2-1 to 2-6, the continuous reinforcing fibers enter the leaf veins and are formed in layers, so it can be said that sufficient strength is obtained.

On the other hand, in Comparative Examples 2-1 to 2-3, the leaf veins were not molded, and the maximum test force was found to be significantly inferior to Examples 2-1 to 2-6. In other words, the maximum test force of Examples 2-1 to 2-6 is 1.87 times higher on average than that of Comparative Examples 2-1 to 2-3, which is higher than that of the conventional ones. It can be said that the strength has also increased significantly.

From the above, when hot-pressing the above CFRTP using a press machine, by heating it at 160°C or higher, it is possible to form rib portions in which continuous reinforcing fibers are inserted, and it is possible to mold CFRTP products with sufficient strength. Preferably, by heating at 200° C. or higher, the finish can be further improved.

Furthermore, when hot pressing the CFRTP using a press machine, it is possible to mold a CFRTP product with sufficient strength in a short time by pressing at a pressure of 10 tons or more.

In addition, in Examples 2-1 to 2-6, in the carbon fiber thermoplastic resin composite material before sample molding, Vf was 45% and the proportions of thermoplastic resin and continuous carbon fiber were approximately the same. However, it can be seen that after sample molding, the proportion of thermoplastic resin tends to be higher in the rib portion than in the base portion. In particular, in the sample product obtained in Example 2-2 shown in FIG. 3(C), it can be seen that the rib portion contains about 80% of the thermoplastic resin. On the other hand, it can be seen that in the base portion, the proportion of continuous carbon fiber tends to be larger than that of thermoplastic resin.

Further, according to the present embodiment, the base 101 and the ribs 102 that protrude from the base 101 and extend in at least one direction are provided, and at least some of the fiber bundles included in the continuous fiber portion 100a are connected to a plurality of fiber bundles. A curved portion that has an inflection point and is curved from the base 101 to return to the base 101 via the rib 102 is covered with the resin portion 100b and is continuously distributed in the extending direction of the rib 101. are doing. As a result, the curved part formed by the fiber bundle extends in the extending direction of the rib part, making it difficult for the rib part to break. , a fiber-reinforced thermoplastic resin composite material that can have higher strength than a carbon fiber-reinforced thermoplastic resin layer that is pre-integrated with a thermoplastic resin, and therefore can produce products with excellent strength. It becomes possible to provide molded products using

Further, according to the present embodiment, since the fiber bundle is coated with thermoplastic resin, continuous fibers are not exposed at the rib portion, and the rib portion does not have intermittent portions of thermoplastic resin in the extending direction of the rib portion. It is possible to give the part a smooth finish, and the finish can be improved.

The functions and effects described in the embodiments of the present invention are merely a list of the most preferable functions and effects resulting from the present invention, and the functions and effects according to the present invention are not described in the embodiments of the present invention. It is not limited to what has been done.

In this embodiment, CFRTP was molded in the manner shown in Comparative Example 2-1, and the mold described above was set and a sample was molded by hot pressing. , the upper surface of the first mold and the press surface of the second mold are both flat, and are heated to a predetermined temperature (e.g. 100°C) and at a predetermined pressure (e.g. 10 t) for a predetermined time ( For example, a sample may be formed by performing a first press process (for example, pressing for 10 seconds) and then hot pressing the CFRTP obtained by reworking the CFRTP by the first press process. Even in this case, the same maximum test force can be obtained.

100 Continuous carbon fiber thermoplastic resin composite material 100a Continuous fiber part 100b Resin part 101 Base (base part)
102 Rib (rib part)
200 Press machine R Thermoplastic resin

The invention according to claim 5 is a molded article using a fiber-reinforced thermoplastic resin composite material containing continuous fibers and a thermoplastic resin,
The base part and
a rib portion protruding from the base portion and extending in at least one direction;
At least some of the fiber bundles included in the continuous fibers have a plurality of inflection points, and a curved portion is formed to curve from the base portion to return to the base portion via the rib portion. The ribs are coated with the thermoplastic resin and are distributed continuously in the extending direction of the rib portion.

The present invention relates to a method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite material, which can produce a product with excellent strength. It is.

In order to solve the above object, the invention according to claim 1 is a method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite material comprising a base and a rib protruding from the base,
a composite material preparation step of preparing a continuous fiber thermoplastic resin composite material in which a continuous fiber sheet made of continuous fibers is impregnated with a thermoplastic resin and solidified;
The base made of the continuous fiber thermoplastic resin composite material is heated at 200° C. or higher and pressed at a pressure of 10 tons or higher to perform hot press molding, and a part of the base is formed into a projecting shape containing the continuous fibers. The method is characterized by including a forming step of forming the ribs by plastic deformation.

According to the present invention, it is possible to provide a method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite material, which can manufacture a product with excellent strength.

Claims (7)

A method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite material comprising a base and a rib protruding from the base, the method comprising:
a composite material preparation step of preparing a continuous fiber thermoplastic resin composite material in which a continuous fiber sheet made of continuous fibers is impregnated with a thermoplastic resin and solidified;
Fiber reinforcement comprising the step of heat press molding the base made of the continuous fiber thermoplastic resin composite material, and plastically deforming a part of the base into a convex shape including the continuous fibers to form the ribs. A method for manufacturing molded products using thermoplastic resin composites. The method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite according to claim 1, wherein in the molding step, the continuous fiber thermoplastic resin composite is heated at 160° C. or higher. The method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite according to claim 1, wherein in the molding step, the continuous fiber thermoplastic resin composite is heated at 200° C. or higher. The method for manufacturing a molded article using a fiber-reinforced thermoplastic resin composite according to any one of claims 1 to 3, wherein in the molding step, the continuous fiber thermoplastic resin composite is pressed at a pressure of 10 tons or more. . A molded product using a fiber-reinforced thermoplastic resin composite material containing continuous fibers and a thermoplastic resin,
The base part and
a rib portion protruding from the base and extending in at least one direction;
At least some of the fiber bundles included in the continuous fibers have a plurality of inflection points, and a curved portion is formed to curve from the base portion to return to the base portion via the rib portion. A molded article using a fiber-reinforced thermoplastic resin composite material, characterized in that the rib portions are coated with the thermoplastic resin and are continuously distributed in the extending direction of the rib portion. 6. The molded article using a fiber-reinforced thermoplastic resin composite material according to claim 5, wherein the continuous fibers in the rib portion are layered. The molded article using the fiber-reinforced thermoplastic resin composite material according to claim 5 or 6, wherein the content ratio of the continuous fibers in the rib portion is larger than the content ratio of the continuous fibers in the base portion.

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