WO2022215606A1

WO2022215606A1 - Method for producing composite molded article

Info

Publication number: WO2022215606A1
Application number: PCT/JP2022/015722
Authority: WO
Inventors: 尚哲金森; 知明栗田
Original assignee: フクビ化学工業株式会社
Priority date: 2021-04-08
Filing date: 2022-03-29
Publication date: 2022-10-13
Also published as: JPWO2022215606A1

Abstract

This method for producing a composite molded article comprises: a step for preparing a plurality of UD tapes, each of which comprises a tape-like base material sheet that is formed of a thermoplastic resin, and reinforcing fibers that are impregnated into the base material sheet in such a manner that the reinforcing fibers are oriented in the same direction; and a step in which the prepared plurality of UD tapes are continuously introduced into a mold, while being stacked upon each other, and subsequently heated, thereby obtaining a composite molded article that has a predetermined cross-sectional shape. A UD tape which has a thickness of 20 μm to 80 μm, a width of 0.5 mm to 10 mm and a weight per square meter of the reinforcing fibers of 30 g/m² to 95 g/m² is used for the above-described UD tapes.

Description

Method for manufacturing composite molded product

The present invention relates to a method for manufacturing a composite molded article containing reinforcing fibers in a thermoplastic resin.

As one method for manufacturing the composite molded product described above, the method disclosed in Patent Document 1 below is known. The manufacturing method described in Patent Document 1 includes a step of tearing a sheet-like prepreg (UD sheet) made of a thermoplastic resin containing reinforcing fibers into a tape shape, and a plurality of obtained tape-like prepregs are formed into a cylindrical shape. and a step of heating by introducing it into a mold (forming die of a drawing device) while distributing it in. This results in a cylindrical composite molding with a constant ring-shaped cross-section.

Here, in Patent Document 1, a tape-shaped prepreg is introduced one by one into each region obtained by dividing a ring-shaped cavity (molding space) defined in a mold into a plurality of regions in the circumferential direction. there is Therefore, in Patent Document 1, it is necessary to set the thickness of each tape-shaped prepreg to a relatively large value equal to or greater than the thickness of the molded product. However, if the thickness of each prepreg is large, the rigidity of each prepreg increases (the shape followability decreases), so it becomes difficult to mold a molded product with a small cross-sectional size or a complicated cross-sectional shape. There is also the problem that voids (cavities) are likely to occur inside the molded product.

JP-A-05-269831

The present invention has been made in view of the circumstances as described above, and an object of the present invention is to manufacture a composite molded product with a high degree of freedom in shape and few voids.

In order to solve the above-mentioned problems, the method for producing a composite molded product of the present invention includes a tape-shaped base sheet made of a thermoplastic resin and a reinforcement impregnated in the base sheet in a state of being oriented in the same direction. A first step of preparing a plurality of UD tapes containing fibers, and continuously introducing the prepared UD tapes into a mold while laminating them and heating them to perform composite molding having a predetermined cross-sectional shape. The UD tape has a thickness of 20 μm or more and 80 μm or less, a width of 0.5 mm or more and 10 mm or less, and a basis weight of the reinforcing fiber of 30 g/m ² or more and 95 g/m ² or less. UD tape is used.

According to the production method of the present invention, it is possible to produce a composite molded product with a high degree of freedom in shape and few voids.

BRIEF DESCRIPTION OF THE DRAWINGS It is a flowchart which shows the schematic procedure of the manufacturing method of the composite molded product which concerns on 1st Embodiment of this invention. It is a figure which shows schematic structure of the apparatus which manufactures UD sheet. FIG. 4 is a diagram showing how a UD tape is cut out from a UD sheet; It is a schematic sectional drawing of UD tape. It is a figure which shows the schematic structure of the apparatus which manufactures a composite molded product from UD tape. 1 is a cross-sectional view showing the structure of a molding die and a composite molded product inside it; FIG. It is a figure equivalent to FIG. 4 which shows the modification of the said 1st Embodiment. 1 is a table showing characteristics of examples of the present invention and comparative examples. FIG. 7 is a view equivalent to FIG. 6 for describing a second embodiment of the present invention; FIG. 10 is a cross-sectional view showing the structure of a composite molded article manufactured in the third embodiment of the present invention; It is a figure which shows schematic structure of the manufacturing apparatus used by the said 3rd Embodiment. 4 is a cross-sectional view showing the structure of a forming die of the manufacturing apparatus; FIG.

(1) First Embodiment FIG. 1 is a flow chart showing a schematic procedure of a method for manufacturing a composite molded product 20 (FIGS. 5 and 6) according to a first embodiment of the present invention. In the present embodiment, the composite molded product 20 is a molded product made of a thermoplastic resin containing reinforcing fibers, and is manufactured by steps (S1 to S3) shown in FIG. That is, the composite molded product 20 of the present embodiment includes a step S1 of molding a UD sheet 1 (FIG. 2), a step S2 of cutting out a plurality of UD tapes 10 (FIG. 3) from the UD sheet 1, and a step S2 of cutting out a plurality of UD tapes 10 (FIG. 3). is subjected to pultrusion to obtain a composite molded product 20 (FIGS. 5 and 6). Details of each step are as follows.

[Molding of UD sheet]
Step S1 is a sheet forming step for forming a UD sheet 1 from a base sheet 2 and reinforcing fibers 3, as shown in FIG. Specifically, in this sheet forming step S1, a base sheet 2 made of a thermoplastic resin and a large number of reinforcing fibers 3 impregnated in a state of being oriented in the same direction on both sides of the base sheet 2 are included. A fiber reinforced resin sheet (FRTP sheet) is molded as a UD sheet 1 .

As the reinforcing fibers 3, carbon fibers, glass fibers, aramid fibers, ceramic fibers, etc. can be used. Among them, carbon fiber is advantageous in improving the strength, corrosion resistance, etc. of the molded product. As the carbon fiber, it is preferable to use PAN (polyacrylonitrile)-based carbon fiber, which has particularly high strength.

The base sheet 2 is a sheet having a certain width and thickness, and is formed, for example, by extruding a thermoplastic resin into a sheet.

The thermoplastic resin that is the material of the base sheet 2, that is, the matrix resin of the UD sheet 1 includes polyamide (especially PA6, PA9T, PA12, PA66), polyethylene, polypropylene, polyphenylene sulfide, polyolefin, polyester, polyacetal, polycarbonate, and acrylic. Resin, acrylonitrile-butadiene-styrene copolymer (ABS), polyamideimide, polysulfone, polyphenylsulfone, polyetherimide, polyethersulfone, polyetheretherketone, polyetherketoneketone, polyimide, polyarylate, fluorine resin, liquid crystal Examples include polymers, thermoplastic epoxy resins, and the like. A polymer alloy obtained by mixing two or more of these thermoplastic resins may also be used as the material for the base sheet 2 .

The UD sheet 1 can be manufactured using, for example, the sheet manufacturing apparatus 50 shown in FIG. This sheet manufacturing apparatus 50 is an apparatus for continuously manufacturing a UD sheet 1 from a fiber bundle 3 ′ that is a bundle of reinforcing fibers and a thermoplastic base sheet 2 .

Specifically, the sheet manufacturing apparatus 50 includes a plurality of pairs (here, two pairs) of heating rollers 51 arranged vertically, and a plurality of pairs (here, two pairs) of cooling rollers 52 arranged vertically below the heating roller 51 . , a pair of endless belts 54 entrained between a heating roller 51 and a cooling roller 52, a pair of drawing rollers 55 arranged below the endless belts 54, and a pair of drawing rollers 55 arranged below the drawing rollers 55. A bobbin 56 for winding is provided.

On both sides of the uppermost heating roller 51, there is provided a spreading mechanism (not shown) that spreads the fiber bundle 3' into a belt shape. This opening mechanism can form a large number of continuous reinforcing fibers 3 spread like a thin strip by continuously opening the fiber bundle 3'. As the fiber spreading mechanism, any mechanism capable of performing such processing may be used, and there are various mechanisms such as a mechanism that spreads the fiber bundle by hitting it, a mechanism that spreads the fiber bundle by blowing air, a mechanism that spreads the fiber bundle by applying ultrasonic waves, and the like. mechanism can be used.

In the example of FIG. 2 , the fiber-spreading mechanism includes a mechanism for supplying the reinforcing fibers 3 after spreading to one side of the base sheet 2 and a mechanism for supplying the reinforcing fibers 3 after spreading to the other side of the base sheet 2 . and a mechanism for supplying The former mechanism is provided to introduce the reinforcing fibers 3 between one surface of the base sheet 2 and the heating roller 51 in contact with the surface, and the latter mechanism is provided to introduce the reinforcing fibers 3 between the other surface of the base sheet 2 and the heating roller 51 in contact with the surface. It is provided so as to introduce the reinforcing fibers 3 between the heating roller 51 in contact with the surface.

The heating roller 51 is a high-temperature roller heated by an electric heater or a heating medium. The heating rollers 51 sandwich the base sheet 2 and the reinforcing fibers 3 introduced on both sides of the base sheet 2 via the endless belt 54 from both sides and heat the base sheet 2 , thereby continuously impregnating the base sheet 2 with the reinforcing fibers 3 . As a result, the reinforcing fibers 3 are impregnated into the base sheet 2 while being aligned in one direction (vertical direction in FIG. 2).

The cooling roller 52 is a low-temperature roller cooled by a cooling medium or the like. The cooling rollers 52 fix the reinforcing fibers 3 to the base sheet 2 by sandwiching the base sheet 2 impregnated with the reinforcing fibers 3 from both sides through the endless belt 54 and cooling the base sheet 2 . As a result, the UD sheet 1 in which the base sheet 2 (matrix resin) and the reinforcing fibers 3 are integrated is molded.

The pull-out roller 55 is a roller that pulls the formed UD sheet 1 downward while applying tension to it.

The winding bobbin 56 is a core material for winding the UD sheet 1. The bobbin 56 is rotationally driven by a drive source such as a motor, and sequentially winds the UD sheet 1 pulled out by the pull-out roller 55 to collect the UD sheet 1 into a roll.

[Molding of UD tape]
Step S2 is a tape cutting step for cutting out the UD tape 10 from the UD sheet 1 formed in the sheet forming step S1. In this tape cutting step S2, as shown in FIG. 3, a plurality of UD tapes 10 are cut out from the UD sheet 1 by forming a plurality of cuts Q1 extending in the longitudinal direction of the UD sheet 1 . Specifically, in the tape cutting step S2, a large number of cuts Q1 extending in the longitudinal direction are formed in the UD sheet 1 by performing cutting from a position P1 in the middle of the feeding path while feeding the UD sheet 1 in the longitudinal direction. . As a result, the UD sheet 1 is finely divided in the width direction to form a plurality of UD tapes 10 each having a relatively small width and being long in the longitudinal direction.

The formation (cutting) of the cuts Q1 in the UD sheet 1 described above can be performed, for example, by using a cutting device including a large number of blades arranged at regular intervals in the width direction of the UD sheet 1 . When a cutting device including blades arranged at regular intervals is used, it is possible to collectively form the UD tape 10 having the same width from the UD sheet 1 . It should be noted that a cutting device having different intervals between adjacent blades may be used for each combination of blades.

As described above, the original sheet from which the UD tape 10 is cut, that is, the UD sheet 1 is a thermoplastic fiber-reinforced resin sheet in which the base sheet 2 is impregnated with the reinforcing fibers 3 . Therefore, each UD tape 10 cut out from the UD sheet 1 also has the base sheet 2 and the reinforcing fibers 3 . That is, as shown in the schematic cross-sectional view of FIG. 4, the UD tape 10 includes a base sheet 2 made of a thermoplastic resin and reinforcing fibers 3 impregnated in the base sheet 2 while being oriented in the same direction. have.

More specifically, in this embodiment, as the UD tape 10, a semi-impregnated UD tape in which both sides of the base sheet 2 are partially impregnated with the reinforcing fibers 3 is used. In other words, the UD tape 10 in this embodiment has a tape-shaped base sheet 2 and reinforcing fibers 3 impregnated only in the surface layer portions on both sides of the base sheet 2 . In this case, most of the reinforcing fibers 3 in the UD tape 10 are impregnated into the base sheet 2 in such a manner that some of them are exposed to the outside of the base sheet 2, and completely impregnated inside the base sheet 2. not. In the sheet forming step S1 described above, the UD sheet 1 is formed so as to obtain the UD tape 10 having such a structure. That is, when forming the UD sheet 1 using the sheet manufacturing apparatus 50 (FIG. 2), the heating rollers 51 (FIG. 2) are used so that the reinforcing fibers 3 are impregnated only in the surface layer portions on both sides of the base sheet 2. The pressure, heating temperature, etc. are adjusted.

As shown in FIG. 4, the thickness of the UD tape 10 is t, and the width is w. The thickness t of the UD tape 10, that is, the total thickness t including the base sheet 2 and the reinforcing fibers 3 on both sides thereof is set to 20 μm or more and 80 μm or less, preferably 25 μm or more and 60 μm or less, more preferably 30 μm or more and 55 μm or less. be. The width w of the UD tape 10 is set to 0.5 mm or more and 10 mm or less, preferably 1 mm or more and 5 mm or less, more preferably 1.5 mm or more and 3 mm or less.

The basis weight of the reinforcing fibers 3 in the UD tape 10, that is, the weight of the reinforcing fibers 3 impregnated per unit area of the base sheet 2 is 30 g/m ² or more and 95 g/m ² or less, preferably 40 g/m ² . 90 g/m ² or more, more preferably 45 g/m ² or more and 85 g/m ² or less.

Table 1 below summarizes the specifications (thickness, width, weight per unit area) of the UD tape 10 described above.

The sheet forming step S1 and tape cutting step S2 described above are carried out in such a manner as to obtain the UD tape 10 having the specifications shown in Table 1 above. That is, in the sheet forming step S1, the UD sheet 1 having a basis weight (30 to 95 g/m ² ) equivalent to the basis weight of the reinforcing fibers 3 in the UD tape 10 shown in Table 1 above is obtained. The density and the like of the reinforcing fibers 3 supplied from the fiber spreading mechanism are adjusted on both sides of the base sheet 2 . Further, in the sheet forming step S1, the thickness of the base sheet 2 and the reinforcing fiber 3 fiber diameter and the like are adjusted. Further, in the tape cutting step S2, cuts Q1 are formed in the UD sheet 1 so that a plurality of UD tapes 10 having a width w (0.5 to 10 mm) shown in Table 1 above are cut out from the UD sheet 1. (FIG. 3) is adjusted.

[Molding of composite molded product]
Step S3 is a drawing step for continuously forming composite molded products 20 from the plurality of UD tapes 10 formed in the tape cutting step S2 using a drawing device 60 shown in FIG. Specifically, in the present embodiment, in the drawing step S3, continuous molding is performed using the drawing device 60 to form the round-bar-shaped composite molded product 20 having a constant circular cross section along the axial direction.

The drawing device 60 includes a tape feeder 61 , a forming die 62 , a cooler 63 , a take-up device 64 and a winder 65 . The tape feeder 61 is a device that collects a plurality of UD tapes 10 and feeds them downstream. The molding die 62 is a mold that receives the UD tape 10 delivered from the tape delivery device 61 and heats and presses it. discharge to the side. The cooler 63 is a device that cools the composite molded product 20 discharged from the molding die 62 . The take-up machine 64 is a device for taking the composite molded product 20 discharged from the cooler 63 and sending it further downstream. The winder 65 is a device that winds up the composite molded product 20 delivered from the take-up machine 64 into a roll.

A tape feeder 61 has a plurality of feed rollers 71 wound with the UD tape 10, and changes the direction of the UD tape 10 so that the UD tape 10 fed by the rotation of the feed rollers 71 is directed to a desired downstream position. A plurality of guide rolls 72 and a plurality of guides 73 for regulating the feed path of each UD tape 10 so that the plurality of UD tapes 10 are gradually aggregated on the downstream side of the group of guide rolls 72 are provided. A plurality of UD tapes 10 are collected vertically and horizontally in the course of passing through all the guides 73 and continuously introduced into the forming die 62 in a state of being stacked on each other.

The molding die 62, as shown in FIG. 6, is a mold divided into upper and lower halves having therein a cavity C1 with a circular cross section corresponding to the shape of the composite molded product 20. That is, the molding die 62 includes an upper die 81 and a lower die 82 arranged in close contact with the lower side of the upper die 81. Semicircular shapes are formed on the opposing surfaces of the upper die 81 and the lower die 82, respectively. A recess is formed. A cavity C1 having a circular cross section is formed by combining the concave portions of the upper mold 81 and the lower mold 82 .

A heating device is built into the molding die 62 . This heating device heats the UD tape 10 introduced into the cavity C1 of the molding die 62, and softens the UD tape 10 by the heating. The softened UD tape 10 is pressurized and deformed in the cavity C1, and changes into a composite molded product 20 having a circular cross section corresponding to the cavity C1. Although the cross-sectional area of the composite molded product 20 can be set variously, it is preferable to set the cross-sectional area to, for example, twice the cross-sectional area of the UD tape 10 or more. This is to obtain the effects (for example, suppression of voids, improvement of mechanical properties, etc.) of the manufacturing method of the present embodiment, which will be described later.

The cooler 63 is arranged downstream and adjacent to the forming die 62 . The cooler 63 may have any structure as long as it can cool the high-temperature composite molded product 20 discharged from the molding die 62. It can be a cold mold into which a coolant is introduced. In this case, the forming die 62 and the cooler 63 can be configured by a series of molds.

An enlarged view of a part of the cross section of the composite molded product 20 is attached to FIG. As shown in this enlarged view, inside the composite molded product 20, a plurality of UD tapes 10 are adhered and fixed to each other in a laminated state. In other words, the composite molded product 20 is a fiber-reinforced composite molded product having a circular cross section formed by layering a plurality of UD tapes 10 containing the base sheet 2 and the reinforcing fibers 3 in the cavity C1. .

The take-up machine 64 includes a plurality of pairs of rollers 91 and a pair of endless belts 92 that are arranged correspondingly in the vertical direction and are wound around the rollers 91 . The rollers 91 feed the composite molded product 20 ejected from the molding die 62 further downstream by rotating while sandwiching the composite molded product 20 from above and below via the endless belt 92 .

The winding machine 65 includes a rotatable winding roller 95 . The take-up roller 95 rotates in a direction to take up the composite molded product 20, and sequentially takes up the composite molded product 20 delivered from the take-up machine 64 to form a roll.

In the drawing step S3, the composite molded product 20 having a circular cross section is continuously formed from the UD tape 10 using the drawing device 60 configured as described above.

[Effect]
As described above, in the present embodiment, a plurality of UD tapes 10 including the tape-shaped base sheet 2 and the reinforcing fibers 3 impregnated in the base sheet 2 are prepared, and the prepared UD tapes 10 are successively introduced into the molding die 62 while being laminated, and the composite molding 20 having a constant cross-sectional shape (circular cross-section in this case) is molded. As described above, according to the present embodiment in which the composite molded product 20 is continuously formed (pultrusion molded) from the UD tape 10, voids (cavities) are formed inside the composite molded product 20 while increasing the degree of freedom in shape of the composite molded product 20. ) can be suppressed.

Specifically, in the present embodiment, the thickness t, the width w, and the basis weight of the reinforcing fibers 3 of the UD tape 10 are set as shown in Table 1 above, so that the UD tape 10 is given appropriate flexibility. In addition, the reinforcing effect of the reinforcing fibers 3 can be sufficiently enhanced. As a result, the mechanical properties (tensile strength, bending strength, etc.) of the composite molded product 20 can be sufficiently improved while reducing the ratio of voids (cavities) generated inside the composite molded product 20 .

For example, since the thickness t of the UD tape 10 is set to 80 μm or less (preferably 60 μm or less, more preferably 55 μm or less), the UD tape 10 is imparted with appropriate flexibility, and the UD tape 10 is appropriately deformed during molding. It can be smoothly introduced into the die 62 . This, together with the fact that the width w of the UD tape 10 is 10 mm or less (preferably 5 mm or less, more preferably 3 mm or less), prevents clogging of the UD tape 10 inside the molding die 62. It is possible to introduce a large number of UD tapes 10 into the forming die 62 in a sufficiently dense state. Therefore, even when molding a composite molded product 20 having a small cross-sectional size or a complicated cross-sectional shape, for example, the cavity C1 of the molding die 62 corresponding to the shape of the composite molded product 20 can be filled with a material at a high filling rate. can be filled, and a high-quality composite molded product 20 with few voids can be obtained.

Further, while the thickness of the UD tape 10 is reduced as described above, the basis weight of the reinforcing fibers 3 is ensured to be 30 g/m ² or more (preferably 40 g/m ² or more, more preferably 45 g/m ² or more). Therefore, the reinforcing fibers 3 can be dispersed relatively uniformly in the resin softened during molding, and the mechanical properties of the composite molded product 20 can be efficiently improved.

As shown in each example (FIG. 8) to be described later, according to the method of the present embodiment for manufacturing a composite molded product 20 using the UD tape 10 having the specifications shown in Table 1, the composite molded product 20 The ratio of voids (cavities) in the can be suppressed to 15% or less. This makes it possible to sufficiently improve the mechanical strength of the composite molded product 20 by a synergistic effect with the above-mentioned effect of uniform dispersion of the reinforcing fibers 3 . Note that the void ratio is the ratio of the cross-sectional area of voids to the entire cross-sectional area of the composite molded product 20 .

Further, in the present embodiment, a semi-impregnated UD tape in which the base sheet 2 is partially impregnated with the reinforcing fibers 3 is used as the UD tape 10 (see FIG. 4). The flexibility of the UD tape 10 can be further enhanced as compared with the case of using a completely impregnated UD tape completely impregnated with 2 (see FIG. 7 described later). As a result, the filling rate of the material filled into the cavity C1 when the UD tape 10 is introduced into the molding die 62 can be increased, and the ratio of voids that can occur in the composite molded product 20 can be sufficiently reduced. . Even when the semi-impregnated UD tape 10 is used as in the present embodiment, the reinforcing fibers 3 are completely impregnated into the resin when the UD tape 10 is introduced into the molding die 62. There are no particular problems with quality.

[Modification]
In the first embodiment, the round bar-shaped composite molded product 20 having a circular cross section is molded from the UD tape 10, but the shape of the composite molded product that can be molded from the UD tape 10 is not limited to this. Molded articles can be molded from the UD tape 10 . For example, it is possible to mold a flat composite molded product having a flattened rectangular cross section.

In the first embodiment, the semi-impregnated UD tape 10 (FIG. 4) in which the base sheet 2 is partially impregnated with the reinforcing fibers 3 is used, but the fully impregnated UD tape as shown in FIG. It is also possible to use 10A. The UD tape 10A is a UD tape in which the base sheet 2 is completely impregnated with the reinforcing fibers 3, and the reinforcing fibers 3 are substantially not exposed to the outside of the base sheet 2. All are impregnated inside the base sheet 2 . When a composite molded product is molded using such a completely impregnated UD tape 10A, a situation occurs in which the reinforcing fibers 3 come off from the base sheet 2 before the UD tape 10A is introduced into the molding die 62. Since it becomes difficult, the reinforcing effect of the composite molding by the reinforcing fibers 3 can be sufficiently enhanced. The fact that both semi-impregnated type and fully impregnated type UD tapes can be used is the same in second and third embodiments described later.

In the first embodiment, the winder 65 for winding the composite molded product into a roll is provided at the most downstream portion of the drawing device 60 (see FIG. 5), but instead of the winder 65, A cutter may be provided for cutting the composite molded article to length.

[Example]
FIG. 8 shows examples 1 to 8 of composite molded articles actually manufactured by the manufacturing method of the first embodiment or its modification described above. That is, under various conditions with different specifications (thickness, width, basis weight) of the UD tape 10, a flat plate-shaped or round-bar-shaped composite molded product was manufactured according to the manufacturing method shown in FIGS. The results are referred to as Examples 1-8, respectively. The manufacturing conditions for each example are as follows.

(manufacturing conditions)
(i) Flat plate shaped article (Examples 1 to 7)
Dimensions: thickness x width = 1mm x 10mm
Matrix resin: PA6
Reinforcing fiber: PAN-based carbon fiber Heating temperature: 250°C
Cooling temperature: 30°C
Line speed: 0.1m/min
(ii) Round bar-shaped molded product (Example 8)
Dimensions: 1.1mm in diameter
Matrix resin: PA6
Reinforcing fiber: PAN-based carbon fiber Heating temperature: 280°C
Cooling temperature: 30°C
Line speed: 0.3m/min

In the above manufacturing conditions, the heating temperature means the heating temperature in the forming die 62 shown in FIG. 5, and the cooling temperature means the cooling temperature in the cooler 63 shown in FIG. . The line speed is the speed at which the composite molded product is taken up by the take-up machine 64 , in other words, the drawing speed at the molding die 62 .

Comparative Examples 1 to 6 are also shown in FIG. Comparative Examples 1 to 6 use UD tape 10 in which any of the thickness, width, and basis weight is outside the range of Table 1, and a flat composite molded product is formed under the same manufacturing conditions as in Examples 1 to 7. This is the result obtained by

As shown in FIG. 8, in Examples 1 to 8 in which the specifications of the UD tape 10 are within the range of Table 1, the void ratio is suppressed to 15% or less. On the other hand, in Comparative Examples 1 to 6, in which the specifications of the UD tape 10 are outside the range of Table 1, the void ratio exceeds 15%, or the shape required as a composite molded product (here, the cross section is 1 × 10 mm flat plate shape) could not be obtained. In FIG. 8, the case where the required shape could not be obtained is indicated as "cannot be molded", and the causes thereof are indicated by (I) to (III). Specifically, unmoldable (I) is a case in which molding failure occurred due to tape breakage in which the UD tape 10 breaks during molding, and unmoldable (II) is a case in which the resin separates from the reinforcing fibers This is a case in which molding failure occurred due to outflow of resin, and molding failure (III) is a case in which molding failure occurred due to insufficient resin.

From the comparison between Examples 1 to 8 and Comparative Examples 1 to 6 described above, it is recognized that the superiority of molding a composite molded product using the UD tape 10 having the thickness, width, and basis weight specified in Table 1. be done.

(2) Second Embodiment In the first embodiment, the solid composite molded product 20 is molded from the UD tape 10, but it is also possible to mold a hollow composite molded product instead of a solid solid composite molded product. An example thereof will be described as a second embodiment.

FIG. 9 is a cross-sectional view showing the structure of the forming die 102 used in the second embodiment. As shown in this figure, in the second embodiment, a composite molded product 20A having a square tubular cross section is continuously molded from the UD tape 10 by pultrusion molding using a molding die 102 . The molding die 102 includes an upper mold 111 and a lower mold 112 which are superimposed one on top of the other, and a core mold 113 disposed between them. A cavity C2 is formed inside the molding die 102 . As the UD tape 10, a UD tape similar to that used in the first embodiment, that is, a UD tape having the thickness, width and basis weight specified in Table 1 above is used. The UD tape 10 is sent from the tape feeder 61 shown in FIG. As a result, the composite molded product 20A having a rectangular cross section corresponding to the shape of the cavity C2 is continuously molded.

As shown in FIG. 9, each corner of the composite molded product 20A is rounded. However, the radius of each rounding is relatively small and its minimum radius is set to 0.1 mm. In general, the filling rate of the material tends to decrease at such small-diameter corners. For this reason, there is a problem that it is originally difficult to ensure the molding quality of the rectangular tube-shaped composite molded product 20A. However, in the second embodiment in which a flexible UD tape 10 having a relatively small thickness t and width w is used (see Table 1), even the rectangular tube-shaped composite molded product 20A can be molded satisfactorily. can. That is, since the use of the flexible UD tape 10 makes it easier for the material to spread to every corner of the cavity C2, each small-diameter corner portion can also be filled with the material at a sufficient filling rate. A quality composite molded product 20A can be obtained.

(3) Third Embodiment In the first and second embodiments, the composite molded product was molded by introducing the UD tape into the molding die, but the molten resin was introduced around the UD tape introduced into the molding die. It is also possible to mold a composite molded product having a two-layer structure. An example thereof will be described as a third embodiment.

FIG. 10 is a cross-sectional view showing the structure of a composite molded product 20B manufactured by the manufacturing method of the third embodiment. As shown in this figure, a composite molded product 20B includes a composite portion 21 and a surface portion 22. FIG. The composite portion 21 is a layer in which the UD tape 10 having the specifications shown in Table 1 above is laminated. In other words, the composite portion 21 is made of a fiber-reinforced resin in which the base sheet 2 (matrix resin) made of thermoplastic resin and the reinforcing fibers 3 are mixed. The surface portion 22 is a layer of thermoplastic resin formed around the composite portion 21 . Unlike the composite portion 21, the surface portion 22 does not contain reinforcing fibers. Composite portion 21 and surface portion 22 are integrated with each other by bringing surface portion 22 into close contact with the outer peripheral surface of composite portion 21 . The material of the surface portion 22 may be the same as or different from the matrix resin of the composite portion 21 .

In the third embodiment, the composite molded product 20B is a flat molded product having a constant rectangular cross section along the axial direction. That is, the composite molded product 20B has a composite portion 21 having a flat rectangular cross section and a rectangular tube-shaped surface portion 22 surrounding the composite portion 21 .

The composite molded product 20B is manufactured using a drawing device 160 shown in FIG. As shown in this figure, the drawing device 160 includes a tape feeder 161 , a forming die 162 , an extruder 166 , a cooler 163 , a take-up device 164 and a cutter 167 . The tape feeder 161 is similar to the tape feeder 61 of the first embodiment (FIG. 5), and collects a plurality of UD tapes 10 and feeds them downstream. The molding die 162 is a mold that receives the UD tape 10 delivered from the tape delivery device 161 and heats and pressurizes it. The extruder 166 is a device for injecting molten resin into the molding die 162 . The cooler 163 is similar to the cooler 63 of the first embodiment, and cools the composite molded product 20B discharged from the molding die 162. As shown in FIG. The take-up machine 164 is similar to the take-up machine 64 of the first embodiment, and takes the composite molded product 20B discharged from the cooler 163 and sends it further downstream. The cutting machine 167 is a device including a cutter 167a that cuts the composite molded product 20B delivered from the take-up machine 164 to a predetermined length.

As shown in FIG. 12, the molding die 62 is a mold divided into upper and lower halves having therein a cavity C3 having a rectangular cross section corresponding to the shape of the composite molded product 20B. That is, the molding die 162 includes an upper mold 181 and a lower mold 182 arranged in close contact with the lower side of the upper mold 181. A cavity C3 having a rectangular cross section is formed between the upper mold 181 and the lower mold 182. It is

The cross-sectional shape of the cavity C3 changes in the middle of the molding die 62. That is, the cavity C3 includes an upstream cavity C3a and a downstream cavity C3b that is one size larger than the upstream cavity C3a. The upstream cavity C3a is a space with a rectangular cross section corresponding to the composite portion 21 of the composite molded product 20B. The downstream cavity C3b is a space having a relatively large rectangular cross section corresponding to the surface portion 22 of the composite molded product 20B, and is formed continuously downstream of the upstream cavity C3a.

The extruder 166, as shown in FIG. 12, includes a cylinder 166a connected to the upper die 181 so as to communicate with the downstream cavity C3b, and a screw 166b arranged inside the cylinder 166a. The screw 166b melts and kneads the resin introduced into the cylinder 166a and pumps it to the lower cavity C3b.

A plurality of UD tapes 10 delivered from the tape delivery device 161 (Fig. 11) are introduced into the upstream cavity C3a and integrated through heating and pressure in the upstream cavity C3a. Thereby, a composite portion 21 having a rectangular cross section corresponding to the upstream cavity C3a is formed. Then, the molten resin discharged from the extruder 166 is supplied around the formed composite portion 21 . That is, by discharging the molten resin from the extruder 166 to the downstream cavity C3b, the gap between the outer peripheral surface of the composite part 21 led to the downstream cavity C3b and the inner peripheral surface of the downstream cavity C3b is filled with the molten resin. be. As a result, a surface portion 22 (FIG. 10) is formed around the composite portion 21, and a composite molded product 20B having a two-layer structure in which both are integrated is molded.

In the third embodiment, as shown in FIG. 10, the fiber-reinforced resin composite portion 21 in which the thermoplastic resin base sheet 2 (matrix resin) and the reinforcing fibers 3 are mixed, and the surroundings thereof An example of molding a composite molded product 20B having a two-layer structure including a covering resin-made surface portion 22 (not containing reinforcing fibers) has been described, but a multi-layer composite molded product having a structure other than this has been described. Molding is also possible. For example, a composite molded product with a two-layer structure in which a part of the periphery of a fiber-reinforced resin composite part is covered with a resin surface part, or a three-layer structure in which the resin surface part is further covered with a fiber-reinforced resin. It is possible to mold a composite molded product of Alternatively, a composite molded article having a two-layer structure in which at least a part of the circumference of a resin core material is covered with a fiber-reinforced resin may be molded.

(4) Summary Each embodiment described above mainly includes the following inventions.

A method for manufacturing a composite molded product according to one aspect of the present invention is a UD tape including a tape-shaped base sheet made of a thermoplastic resin and reinforcing fibers impregnated in the base sheet while being oriented in the same direction. A first step of preparing a plurality of the UD tapes, and a second step of forming a composite molded product having a predetermined cross-sectional shape by continuously introducing the prepared UD tapes into a mold while laminating and heating. and the steps of As the UD tape, a UD tape having a thickness of 20 μm or more and 80 μm or less, a width of 0.5 mm or more and 10 mm or less, and a basis weight of the reinforcing fibers of 30 g/m ² or more and 95 g/m ² or less is used.

According to the present invention, since the UD tape has a thickness of 80 μm or less, the UD tape is imparted with appropriate flexibility, and can be smoothly introduced into the mold while being properly deformed. This, together with the fact that the width of the UD tape is 10 mm or less, has the effect of preventing clogging of the UD tape in the mold. It becomes possible to introduce it into the mold. Therefore, for example, even when molding a composite molded product with a small cross-sectional size or a complicated cross-sectional shape, it is possible to fill the cavity of the mold corresponding to the shape of the composite molded product with a high filling rate. It is possible to obtain a high-quality composite molded product with few voids (cavities).

In addition, while the thickness of the UD tape is reduced as described above, the basis weight of the reinforcing fibers is ensured to be 30 g/m ² or more. It is possible to efficiently improve the mechanical properties of the composite molded product.

Preferably, the UD tape has a thickness of 25 μm or more and 60 μm or less, a width of 1 mm or more and 5 mm or less, and a basis weight of the reinforcing fibers of 40 g/m ² or more and 90 g/m ² or less.

By doing so, the above effects can be further enhanced.

More preferably, the UD tape has a thickness of 30 μm or more and 55 μm or less, a width of 1.5 mm or more and 3 mm or less, and a basis weight of the reinforcing fibers of 45 g/m ² or more and 85 g/m ² or less.

By doing so, the above effects can be further enhanced.

Preferably, as the UD tape, a semi-impregnated UD tape in which the base sheet is partially impregnated with the reinforcing fibers is used.

Thus, when the semi-impregnated UD tape is used, the flexibility of the UD tape is reduced compared to the case of using the fully impregnated UD tape in which the reinforcing fibers are completely impregnated into the base sheet. can be higher. As a result, it is possible to increase the filling rate of the material that fills the cavity when the UD tape is introduced into the mold, and to sufficiently reduce the percentage of voids that may occur in the composite molded product.

Preferably, in the second step, a composite molded product having a cross-sectional area that is at least twice the cross-sectional area of the UD tape is formed.

By doing so, it is possible to accurately obtain the above-described effects (suppression of voids, improvement of mechanical properties, etc.).

The manufacturing method of the present invention may further include a third step of supplying molten resin around the UD tape introduced into the mold.

By doing so, it is possible to manufacture a composite molded article having a two-layer structure including the composite portion laminated with the UD tape and the resin-made surface portion formed therearound.

Claims

a first step of preparing a plurality of UD tapes each including a tape-shaped base sheet made of a thermoplastic resin and reinforcing fibers impregnated in the base sheet while being oriented in the same direction;
A second step of forming a composite molded product having a predetermined cross-sectional shape by continuously introducing the prepared UD tapes into a mold while laminating them and heating them,
As the UD tape, a UD tape having a thickness of 20 μm or more and 80 μm or less, a width of 0.5 mm or more and 10 mm or less, and a basis weight of the reinforcing fiber of 30 g/m 2 or more and 95 g/m 2 or less is used. A method of manufacturing molded articles.
In the method for manufacturing a composite molded product according to claim 1,
A molded composite article characterized in that the UD tape has a thickness of 25 μm or more and 60 μm or less, a width of 1 mm or more and 5 mm or less, and a basis weight of the reinforcing fibers of 40 g/m 2 or more and 90 g/m 2 or less. manufacturing method.
In the method for manufacturing a composite molded product according to claim 2,
As the UD tape, a UD tape having a thickness of 30 μm or more and 55 μm or less, a width of 1.5 mm or more and 3 mm or less, and a basis weight of the reinforcing fiber of 45 g/m 2 or more and 85 g/m 2 or less is used. A method of manufacturing molded articles.
In the method for manufacturing a composite molded article according to any one of claims 1 to 3,
A method for producing a composite molded article, wherein a semi-impregnated UD tape in which the base sheet is partially impregnated with the reinforcing fibers is used as the UD tape.
In the method for manufacturing a composite molded article according to any one of claims 1 to 4,
A method for producing a composite molded product, wherein in the second step, a composite molded product having a cross-sectional area that is at least twice the cross-sectional area of the UD tape is molded.
In the method for producing a composite molded product according to any one of claims 1 to 5,
A method for producing a composite molded product, further comprising a third step of supplying a molten resin around the UD tape introduced into the mold.