PP-FRP member and manufacturing method thereof

Abstract

Provided are: a high-strength PP-FRP member having excellent shape stability by integrating laminated composite layers with each other; and a method for manufacturing the high-strength PP-FRP member. A PP-FRP member (100) is provided with a plurality of composite layers (111-114) each having a sheet-like woven fabric and a polypropylene impregnated and fixed in meshes of the woven fabric, the plurality of composite layers (111-114) being laminated, adjacent woven fabrics being in contact with each other, and the polypropylene being filled in the meshes of the woven fabric and integrated with the meshes of the woven fabric. As a result, a high-strength PP-FRP member having excellent shape stability can be obtained by integrating the laminated composite layers (111-114) with each other.

Description

Technical Field

[0001] The present invention relates to a PP-FRP (Fiber Reinforced Plastics) component and a method for manufacturing the same. Background Art

[0002] In the past, as a resin decoration molding technology, a method of making a component by impregnating a resin into a fiber is known (for example, Patent Documents 1 and 2). As the resin for impregnation at this time, for example, PVB (polyvinyl butyral) is used. The component formed by integrating the resin and the fiber layer has sufficient strength. In such a component, the base resin layer formed by injection molding also infiltrates and fixes (Japanese original text: fixes) in the gaps between the fibers of the non-woven fabric layer.

[0003] In the housing described in Patent Document 1, the nonwoven fabric layer is bonded to the decorative layer via an adhesive resin layer. The adhesive resin layer uses, for example, PVB (polyvinyl butyral) having a viscosity that allows bubbles in the adhesive resin layer to be released by softening. Patent Document 1 also discloses that polypropylene is used as an example of a material for a base resin layer constituting the housing; and that the adhesive resin layer has a built-in wire.

[0004] Patent document 2 discloses a flat-cut veneer sheet and its application product, in which a non-woven fabric mainly composed of fibers capable of maintaining a shape at a temperature higher than the melting point of the resin film is sandwiched between the back of the flat-cut veneer and the resin film, and the resin film is formed like FRP. In addition, PET fiber is cited as an example of the non-woven fabric, and a propylene film is cited as an example of the resin film. In the flat-cut veneer sheet described in Patent document 2, the non-woven fabric and the base resin are firmly bonded by exerting an anchoring effect between the non-woven fabric and the base resin.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-175641

[0008] Patent Document 2: Japanese Patent Application No. 2013-190839 Summary of the invention

[0009] Problems to be solved by the invention

[0010] Polypropylene can not only be obtained at low cost, but also has excellent chemical resistance and has the possibility of being applied to various uses. The inventors of the present invention have endeavored to produce an integrated laminate using only polypropylene as the resin infiltrated into the fibers of the nonwoven fabric. However, even when multiple sheets formed of polypropylene are overlapped and thermocompression bonded, the layers derived from the sheets will peel off from the product, and the form of only polypropylene components cannot firmly integrate the whole, which is common knowledge in the forming field.

[0011] In Patent Document 2, as an example of the resin film, a film of propylene is cited. However, impregnating the resin into the nonwoven fabric is only to fix the plain cut veneer sheet to the plain cut veneer, and only a single layer for fixing is formed. Therefore, it is difficult to use the plain cut veneer sheet as an FRP member that requires shape stability and strength for design like an automobile body.

[0012] The present invention has been completed in view of such circumstances, and its object is to provide: a high-strength PP-FRP member with excellent shape stability achieved by integrating laminated composite layers with each other; and a manufacturing method thereof.

[0013] Means for Solving the Problem

[0014] (1) In order to achieve the above object, the present invention adopts the following scheme. That is, the PP-FRP member of the present invention is characterized in that it includes a plurality of composite layers, the plurality of composite layers having a sheet-like fabric and polypropylene infiltrated into the meshes of the fabric and fixed therein, the plurality of composite layers being laminated, adjacent fabrics contacting each other, and the polypropylene filling the meshes of the fabric and integrating. Thus, by integrating the laminated composite layers with each other, a high-strength PP-FRP member with excellent shape stability can be obtained.

[0015] (2) Further, in the PP-FRP member described in the above (1), it is characterized in that the fabric constituting any layer of the plurality of composite layers is a nonwoven fabric. Thus, by overlapping prepregs obtained by infiltrating polypropylene into nonwoven fabrics and pressing them, it can be easily formed.

[0016] (3) Further, in the PP-FRP member described in the above (1), it is characterized in that one of the fabrics of the adjacent composite layers constituting the plurality of composite layers is a nonwoven fabric and the other is a woven fabric. Such a structure is formed by sandwiching a woven fabric between prepregs, so the shape stability is improved.

[0017] (4) Further, in the PP-FRP member described in any one of the above (1) to (3), it is characterized in that it further includes a conductive material provided between the fabrics of the adjacent plurality of composite layers. Thus, various functions can be obtained by using the conductive material.

[0018] (5) Additionally, in the PP-FRP member described in any one of (1) to (4) above, it is characterized in that the melting point of the polypropylene is 160°C or lower. Thus, processing can be carried out at low temperatures, and the PP-FRP member can be used, for example, for surface decoration.

[0019] (6) Additionally, in the PP-FRP member described in any one of (1) to (5) above, it is characterized in that the polypropylene contains 5 wt% or more and 30 wt% or less of a tackifier. Thus, prepregs can be easily prepared using hot melt.

[0020] (7) Additionally, in the PP-FRP member described in any one of (1) to (6) above, it is characterized in that when hot pressing is carried out at a temperature of 100°C or higher and 150°C or lower and a pressure of 2.5 MPa or lower, the rate of change in length before and after the hot pressing is 1% or lower. By making the shape stability of the PP-FRP member excellent in this way, application also becomes easier.

[0021] (8) Additionally, the manufacturing method of the PP-FRP member of the present invention is characterized by including: a step of overlapping a plurality of prepreg sheets having a non-woven fabric and polypropylene impregnated in the non-woven fabric to form a first overlapping body; and a step of hot pressing the first overlapping body at a temperature of a specified temperature or higher and a pressure of a specified pressure or higher. Thus, a plastic member with low cost, excellent chemical resistance, density, and high strength can be manufactured.

[0022] (9) Additionally, in the manufacturing method of the PP-FRP member of the present invention, it is characterized by including: a step of alternately overlapping a plurality of prepreg sheets having a woven fabric and polypropylene impregnated in the woven fabric with a sheet-like fabric to form a second overlapping body; and a step of hot pressing the second overlapping body at a temperature of a specified temperature or higher and a pressure of a specified pressure or higher. Thus, a plastic member with low cost, excellent chemical resistance, density, and high strength can be manufactured. Further, the shape stability can also be improved.

[0023] (10) Additionally, in the manufacturing method of the PP-FRP member described in (8) or (9) above, it is characterized in that the specified temperature is 100°C or higher and 150°C or lower, and the specified pressure is 1.5 MPa or higher and 2.5 MPa or lower. Thus, the laminated composite layers are integrated with each other, and a high-strength PP-FRP member with excellent shape stability can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view showing a PP-FRP member.

[0025] Figure 2 of (a) toFigure 2 (c) is a cross-sectional view showing the process of manufacturing the prepreg.

[0026] Figure 3 is a perspective view showing the process of overlapping and thermocompression bonding the prepregs.

[0027] Figure 4 is a perspective view showing the process of thermocompression bonding the prepreg and the fabric.

[0028] Figure 5 (a) to Figure 5 (d) are cross-sectional views showing the processes of forming and trimming, respectively.

[0029] Figure 6 (a), Figure 6 (b) are cross-sectional views showing the PP-FRP member in which a wire and components are embedded, respectively.

[0030] Figure 7 is a micrograph of the cross-section. Detailed Description of the Invention

[0031] The inventors of the present invention repeated trial and error, overlapped prepregs obtained by impregnating polypropylene into a sheet-like nonwoven fabric and fixing it, and joined them by thermocompression bonding, thereby manufacturing a PP-FRP member, and thus completed the present invention. By making the polypropylene impregnated in the mesh of the nonwoven fabric continuous in multiple layers, the laminate can be firmly integrated while maintaining shape stability. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0032] [First Embodiment]

[0033] [Structure of PP-FRP Member]

[0034] Figure 1 is a cross-sectional view showing the PP-FRP member 100. Figure 1 As an example of the shown mode, the PP-FRP member 100 is formed by composite layers 111 to 114. The composite layers 111 to 114 are laminated, and each of the composite layers 111 to 114 is formed of a fabric and polypropylene impregnated in the mesh of the fabric and fixed.

[0035] In the composite layers 111 to 114, polypropylene continuously exists across the layers and infiltrates into the mesh of the fabric. Due to the anchoring effect of the infiltrated polypropylene, each of the composite layers 111 to 114 is firmly joined to the adjacent layer. In this way, a firmly integrated plate-like member is formed.

[0036] The polypropylene preferably contains 5 wt% or more and 30 wt% or less of a tackifier. The tackifier is a tackifying resin, for example, a petroleum-based one is used. Thereby, the preparation of the prepreg becomes easy by hot melting.

[0037] As the polypropylene, a polypropylene with a high melting point can be used. Such a polypropylene with a high melting point is a high-shrinkage material and can be used for components for products that require a high elastic modulus. As the polypropylene with a high melting point, for example, a polypropylene with a melting point of 150 °C or higher is preferably used. Such a polypropylene with a high melting point is preferably formed from 85 wt% or more and 95 wt% or less of polypropylene and 5 wt% or more and 15 wt% or less of a tackifier.

[0038] In addition, as the polypropylene, a polypropylene with a low melting point can also be used. Such a polypropylene with a low melting point is a low-shrinkage type and is slightly softer than the polypropylene with a high melting point. It can be used for impregnating synthetic fiber fabrics with a low heat-resistant temperature such as polyethylene reinforcing fibers. As the polypropylene with a low melting point, for example, a polypropylene with a melting point of 100 °C or lower is preferably used. Such a polypropylene with a low melting point is preferably formed from 70 wt% or more and 85 wt% or less of polypropylene and 15 wt% or more and 30 wt% or less of a tackifier.

[0039] The melting point of the polypropylene is preferably at least 160 °C or lower. Thereby, it can be processed at a low temperature and can be joined to components with different melting points. For example, a component with a surface decoration made of polypropylene with a high melting point can be formed, and this component can be joined to a PP-FRP component.

[0040] It is preferred that all of the fabrics included in the composite layers 111 to 114 are non-woven fabrics, or non-woven fabrics and woven fabrics are alternately overlapped. The non-woven fabric is preferably a spunbond non-woven fabric, and particularly preferably a spunbond non-woven fabric containing polyester. The non-woven fabric can also be a paper-making non-woven fabric or felt containing polyester. As the fabric, a fabric with a basis weight of 20 g / m 2 or more and 300 g / m 2 or less can be used.

[0041] As the non-woven fabric, a non-woven fabric made of polypropylene can also be used. The non-woven fabric made of polypropylene has a large volume. For example, when using a non-woven fabric made of polypropylene with a basis weight of 20 g / m 2 or more and 70 g / m 2 or less, since the porosity is high, the softened polypropylene in the hot melt process is likely to infiltrate. In this case, there is also an advantage in terms of cost that the same thickness of the composite layer can be formed with a smaller number of non-woven fabric sheets. In addition, the composite layer obtained by impregnating the polypropylene into the non-woven fabric made of polypropylene does not need to be separated into each material during reuse.

[0042] As the woven fabric, a woven fabric of polyethylene reinforcing fibers can also be used. When using a polyester non-woven fabric, the basis weight is preferably 30 g / m 2 or more and 250 g / m 2 or less. Thereby, the softened polypropylene will be likely to infiltrate.

[0043] In the PP-FRP member 100, the composite layers 111 to 114 have a four-layer structure, but may also be laminated in other numbers. By setting it to four or more layers, the strength of the PP-FRP member 100 can be improved and the shape can be stabilized. On the other hand, if it is less than four layers, the forming becomes easier.

[0044] [Manufacturing method of PP-FRP member]

[0045] A manufacturing method of the PP-FRP member 100 configured as described above will be described. The PP-FRP member 100 is manufactured through processes of prepreg production, hot press bonding, preform forming, and trimming. Figure 2 of (a) to Figure 2 of (c) are cross-sectional views respectively showing the processes of prepreg production.

[0046] First, prepreg is produced. For example, as Figure 2 shown in (a), with the surface made horizontal, the sheet-shaped non-woven fabric 10 is placed, and polypropylene 20 heated to a temperature exceeding the softening point and softened is coated from above and infiltrated and fixed thereto, whereby prepreg 30 can be produced. As the non-woven fabric 10, a non-woven fabric with a thickness of 50 μm or more and 500 μm or less is preferably used.

[0047] In the coating process, as a coating machine based on hot melt, a device called a melter can be used. Figure 2 The device example shown in (a) is a single-sheet coater. By fixing the non-woven fabric 10 and moving the spray-type nozzle part M1 over the entire non-woven fabric 10, polypropylene 20 can be coated on the non-woven fabric 10 to produce prepreg 30.

[0048] Figure 2 The device example shown in (b) is a roll-to-roll continuous impregnation device. By fixing the spray-type nozzle part M2 and moving the non-woven fabric 10 from the roller R1 to the roller R2, polypropylene 20 can be coated on the entire non-woven fabric 10 to produce prepreg 30. In the above coating machines, during coating, it is preferable to move one of the coating machine side or the non-woven fabric side relative to the other at a constant speed.

[0049] Figure 2 The device example shown in (c) is also a continuous impregnation device using rollers. The discharge-type nozzle M3 is fixed, and polypropylene 20 is supplied to the position between the rollers R3 and R4. Polypropylene 20 infiltrates into the non-woven fabric 10 fed while being clamped between the rollers R3 and R4. Such a continuous impregnation device can be used to improve the production efficiency of prepreg 30.

[0050] It is also possible to accumulate the heat-softened polypropylene in a container and immerse the sheet-like fabric in the container (so-called "dipping"). By cooling the polypropylene infiltrated into the fabric in this way, it is solidified, and thus a prepreg is formed. In this case, it is preferable to continuously move the fabric at a constant speed by rotation of a roller or the like so that the fabric passes through the polypropylene.

[0051] The obtained sheet-like prepreg preferably has a thickness of 100 μm or more and 1500 μm or less, and more preferably a thickness of 100 μm or more and 500 μm or less.

[0052] A plurality of obtained sheet-like prepregs 30 are overlapped and arranged according to a specified design to form an overlapping body (first overlapping body). Then, based on heating the arranged overlapping body, pressing is performed for thermocompression bonding. Figure 3 is a perspective view showing the process of overlapping and thermocompression bonding prepregs. In Figure 3 the example shown, while heating the overlapping body 40a obtained by overlapping 4 prepregs 31 to 34 from above and below, pressing is performed. As a result, a sheet-like laminate is formed.

[0053] For thermocompression bonding, it is preferable to use a hydraulic hot press or a multi-stage press and perform thermocompression at a temperature above a specified temperature and a pressure above a specified pressure. The specified temperature is a temperature below the melting point and above the softening point of polypropylene. For example, it is preferably heated to 140 °C or more and 160 °C or less. The specified pressure is preferably 1.5 MPa or more and 2.5 MPa or less. Thereby, polypropylene infiltrates into the meshes in the fabric and is fixed, and thus an anchoring effect is generated, and the members can be firmly integrated.

[0054] In this way, by performing thermocompression bonding on the prepreg at a temperature higher than the softening point and lower than the melting point of polypropylene, the polypropylene infiltrated into the meshes is continuously integrated and firmly fixed to the meshes by the anchoring effect. As a result, a sheet of the PP-FRP member 100 is generated in the form of a laminated sheet obtained by firmly joining a plurality of non-woven fabrics with the polypropylene spread by infiltration.

[0055] The PP-FRP member 100 has excellent shape stability, and when thermocompression is performed at a temperature of 100 °C or more and 150 °C or less and a pressure of 2.5 MPa or less, the absolute value of the change rate of the length before and after pressing is 1% or less. In this way, the dimensions of the PP-FRP member are not likely to change before and after pressing. Therefore, the PP-FRP member can be formed according to the design, and the application becomes easier.

[0056] After the lamination of the PP-FRP member 100 based on hot pressing, the shape can be stabilized by natural cooling. Therefore, it is also possible to mass-produce a large number of them simultaneously using a multi-stage press. A multi-stage press is a hot press that has a hot plate arranged in the middle in addition to the upper and lower hot plates, and has a plurality of openings as positions (Japanese original: "dan") for clamping materials. The material can be clamped at a plurality of positions, and while heating, it is pressed by the press to simultaneously form a plurality of PP-FRP members.

[0057] The PP-FRP member has a structure of a composite layer in which polypropylene infiltrates into the fabric and is fixed, and thus has high strength. Therefore, it can be used for lightweight and strength-required members such as the body of an automobile.

[0058] The sheet of the PP-FRP member 100 obtained in the above process is formed and trimmed. Figure 4 of (a) to Figure 4 of (d) is a cross-sectional view showing the processes of forming and trimming. First, the laminate 41 is softened by heating. Then, as Figure 4 shown in (a) of, the laminate 41 is arranged between the male mold D1 and the female mold D2.

[0059] Next, as Figure 4 shown in (b) of, the male mold D1 and the female mold D2 are closed. As a result, the laminate 41 is shaped. After closing the mold, as Figure 4 shown in (c) of, the male mold D1 and the female mold D2 are opened, and the obtained formed body 42 is demolded. Then, as Figure 4 shown in (d) of, unnecessary portions are removed by trimming to obtain a formed body 43. Even after such forming processing, the change rate of the length from the laminate 41 to the formed body 43 is within 1%, and the shape stability of the PP-FRP member 100 is excellent. The obtained PP-FRP member 100 is appropriately further machined by cutting according to the use. The PP-FRP member 100 can be applied to various products using polypropylene as the surface material.

[0060] [Second Embodiment]

[0061] In the above-described embodiment, only the prepregs are overlapped and hot-pressed, but the prepregs and the fabric can be alternately overlapped and hot-pressed. Figure 5 is a perspective view showing the process of hot-pressing the prepreg and the fabric. The fabric alternately overlapped with the prepreg is a woven fabric or a non-woven fabric. In Figure 5In the example shown, an overlapping body 40b (second overlapping body) is formed by alternately overlapping two prepregs 35 to 36 and two fabrics 51 to 52, and hot pressing of the overlapping body 40b is performed. As a result, a sheet-like laminate is formed. The hot pressing in this case can also be performed using the same equipment as in the first embodiment under the same temperature conditions.

[0062] In this case, by performing hot pressing of the prepreg and the fabric at a temperature higher than the softening point of polypropylene and lower than the melting point, the polypropylene in the prepreg also infiltrates into the meshes of the fabric and is firmly fixed to the meshes by the anchoring effect. As a result, a sheet of the PP-FRP member 100 is generated in the form of a laminate sheet obtained by joining the prepreg and the fabric using polypropylene that continuously spreads through infiltration.

[0063] [Third Embodiment]

[0064] [Structure of Circuit Component Embedded Type PP-FRP Member]

[0065] A conductor can be embedded in the main body layer of the above PP-FRP member 100. Figure 6 of (a), Figure 6 of (b) are cross-sectional views of PP-FRP members 200 and 300 in which a wire and an element are embedded in the main body layer, respectively. The PP-FRP member 200 is basically configured in the same manner as the PP-FRP member 100, but has the embedding of the wire 231 and features related thereto.

[0066] In the PP-FRP member 200, a wire 231 is provided between the composite layer 211 and the composite layer 212. In this way, a PP-FRP member 200 that is firmly integrated using polypropylene and has additional functions due to the wire 231 provided inside can be formed.

[0067] In Figure 6 In the example shown in (a) of, a wire 231 having a circular cross-section is provided between the composite layer 211 and the composite layer 212. The wire 231 is, for example, a wire for power supply or control of each device. Since the PP-FRP member 200 is formed by hot pressing while clamping the wire 231, a semicircular depression corresponding to the cross-sectional shape of the wire is generated in the composite layer 212 that is pressed by the wire 231. In this way, since the composite layers 211 and 212 are softly deformed, the upper surface of the composite layer 211 can be made smooth. Since it is embedded between the composite layers, there is no problem even if the conductive material of the wire 231 is exposed without an insulating coating.

[0068] Note that in the above example, the wire 231 is disposed between the non-woven fabrics within the composite layer. However, in the case where non-woven fabrics and woven fabrics are alternately arranged, the wire 231 can also be disposed between the non-woven fabric and the woven fabric. That is, the wire 231 only needs to be embedded inside the multiple-layer structure constituting the PP-FRP member 200, and in this case, it can be embedded between any layers.

[0069] On the other hand, the PP-FRP member 300 is also basically configured in the same manner as the PP-FRP member 200, but the element 331 embedded in the PP-FRP member 300 and its related features are different. In Figure 6 In the example shown in (b) of, a flat-plate-shaped element in cross-section is disposed between the composite layer 311 and the composite layer 312 as the element 331. The composite layer 312 pressed by the element 331 in the manufacturing process generates a flat-shaped depression corresponding to the cross-sectional shape of the element.

[0070] The manufacturing processes of the PP-FRP members 200 and 300 are the same as those of the PP-FRP member 100. However, they are different in that the wire 231 or the element 331 is disposed between them when the prepreg and the fabric are arranged.

[0071] [Large Components and Shells]

[0072] The PP-FRP member, as a large and strength-required component or shell, can be used for, for example, the body and bumper of an automobile, and household equipment. The PP-FRP member has excellent shape stability, and its dimensions do not change due to shrinkage after the hot pressing process. Therefore, large components can be manufactured as designed as a substitute for steel products. By decorating the surface layer of the PP-FRP member with a polyester non-woven fabric or a woven fabric as a coating base fabric and subjecting the surface layer to PET resinization, coating can also be achieved. In this way, it can also be applied to components that require coating such as the exterior of an automobile. In addition, by using a polyester conductive woven fabric in the surface decoration, non-electrification of the entire component can also be achieved.

[0073] [Wire Harness]

[0074] The PP-FRP member in which a wire is embedded can be used for a wire harness (Japanese original text: ワイヤーハーネス), and the wire is a wire for supplying power to a device and a wire for transmitting an electrical signal of a control device. Since the wire is embedded between the composite layers, a wire harness in which adverse conditions such as short circuits in the circuit are not likely to occur can be realized. A touch panel and an antenna can also be built into the PP-FRP member.

[0075] [Toilet Seat]

[0076] The PP-FRP member embedded with a heating wire as a conductor can also be used for a toilet seat. The toilet seat is a so-called heated toilet seat, and by passing an electric current through the heating wire, the surface temperature can be maintained at about 40 °C. The material of the heating wire is not particularly limited. It is possible to realize a heated toilet seat with a surface formed of polypropylene having excellent acid resistance to salt. If the heating wire is provided directly below the composite layer on the surface, heat can be easily conducted to the surface, and the heat efficiency can be improved. In addition, the PP-FRP member can also be used for a toilet seat without embedding a heating wire. In this case, it is preferable to use a surface material that has been processed to have a good skin feel such as flocking.

[0077] [Gasket]

[0078] The PP-FRP member can be used as a gasket for a composite laminate of a PP film and a non-woven fabric. In addition, it can also be used as a gasket for a composite laminate of a resin film such as PMMA, PET, or PC and a non-woven fabric. In this case, PVB resin is used as an adhesive for bonding the resin film and the non-woven fabric. Further, as the base resin, other resins such as ABS resin, PP, PC, or PMMA can also be injection-molded on the back surface. In this way, it can be applied to various uses as an intermediate processing material with a low processing temperature, for example, in the range of 120 to 150 °C and being lightweight.

[0079] [Experiment 1]

[0080] The hot-melt polypropylene (HMPP) added with a tackifier is heated to soften it, and the softened polypropylene is coated on a non-woven fabric made of a spunbond polyester to prepare a prepreg. As the non-woven fabric, Toray Industries, Inc. non-woven fabric N2070-6S is used. For convenience, the prepreg obtained by using a hot-melt polypropylene with a low melting point (95 °C) (PP 80 wt%, tackifier 20 wt%) is referred to as "prepreg 2". The obtained prepregs are overlapped according to the following combinations.

[0081] [Table 1]

[0082]

[0083] The black non-woven fabric has a higher density and is harder than a normal non-woven fabric. As the black non-woven fabric, Toray Industries, Inc. non-woven fabric G2200-BKO is used. The coarse white non-woven fabric has a lower density than a normal non-woven fabric. As the coarse white non-woven fabric, Toray Industries, Inc. non-woven fabric D5100 is used.

[0084] On the surface of the specimen obtained by overlapping materials, draw a square with a side length of approximately 100 mm using a sign pen with a tip thickness of 0.5 mm. Measure the length of each side twice and average them. The length is measured to the unit of 0.01 mm using a digital vernier caliper (the same applies hereinafter). Press each specimen for 1 minute using a hydraulic hot press to perform hot pressing. When hot pressing the laminate specimen 3, in order to prevent detachment during pressing, the specimen is flattened and overly compressed, and a 15-mm spacer is engaged.

[0085] After hot pressing, measure the length of each side of the square twice and average them. The rate of change in the length of the square of the laminate specimens 1 to 3 obtained as PP-FRP members is within 1%. The measurement results are shown in the following table.

[0086] [Table 2]

[0087]

[0088] Next, hot press the specimen obtained by laminating a prepreg using a high-melting-point (155 °C) hot-melt polypropylene (PP 90 wt%, tackifier 10 wt%) and a prepreg using a low-melting-point (95 °C) hot-melt polypropylene, and clamping both ends with non-woven fabric. For convenience, the prepreg using a high-melting-point (155 °C) hot-melt polypropylene is referred to as "prepreg 1". Overlap the materials according to the following combinations.

[0089] [Table 3]

[0090]

[0091] On the surface of the specimen obtained by overlapping materials, draw a square with a side length of approximately 100 mm using a sign pen. Measure the length of each side twice and average them. Press each specimen for 1 minute using a hydraulic hot press to perform hot pressing. After hot pressing, measure the length of each side of the square twice and average them. The rate of change in the length of the square of the laminate specimens 4 and 5 obtained as PP-FRP members is within 1%. The measurement results are shown in the following table.

[0092] [Table 4]

[0093]

[0094] Next, hot press the specimen obtained by laminating a prepreg using a high-melting-point (155 °C) hot-melt polypropylene and non-woven fabric. Overlap the materials according to the following combinations.

[0095] [Table 5]

[0096]

[0097] On the surface of the specimen obtained by overlapping materials, draw a square with a side length of approximately 100 mm using a signature pen. Measure the length of each side twice and average them. Use a hydraulic hot press to press each specimen for 1 minute to perform hot pressing. After hot pressing, measure the length of each side of the square twice and average them. The rate of change in the length of the square of the laminate specimens 6 and 7 obtained as PP-FRP members is within 1%. The measurement results are shown in the following table.

[0098] [Table 6]

[0099]

[0100] As described above, in any laminate specimen, the rate of change in length before and after hot pressing is 1% or less, indicating extremely excellent shape stability. In particular, when prepregs using low-melting-point hot-melt polypropylene are laminated and hot pressing is performed at a relatively low temperature of 120°C or less, the rate of change is 0.4% or less. From such results, it can be seen that not only the shape stability during the manufacture of PP-FRP members, but also the rate of change of the manufactured PP-FRP members is 1% or less when hot pressing is performed at a temperature of 100°C or more and 150°C or less and a pressure of 2.5 MPa or less, and the shape stability is extremely excellent.

[0101] [Experiment 2]

[0102] For comparison, a 100% polypropylene (PP) film with a thickness of 0.5 mm was heat-treated for 1 minute. The heat treatment was carried out under the following temperature, pressure, and measurement conditions. Before the heat treatment, draw a square with a side length of approximately 100 mm on the surface of the specimen, measure the length of each side twice and average them. In addition, measure the length of each side of the square twice after the heat treatment and average them to calculate the rate of change.

[0103] [Table 7]

[0104]

[0105] It can be seen that when a pressure of 2 MPa is applied to a polypropylene film specimen 4 or 6 at a temperature exceeding the softening point, the shape changes. Regarding these, the rate of change exceeds 1%, and it can be seen that sufficient shape stability cannot be obtained even when laminating polypropylene films to make a laminate.

[0106] [Experiment 3]

[0107] Cut the PP-FRP member obtained in Experiment 1 and observe the cut surface with a microscope. Figure 7 This is a micrograph of the cut surface. As Figure 7As shown, it can be seen that a PP-FRP member 400 is formed by laminating a composite layer 411 made of prepreg and a composite layer 412 made of non-woven fabric. It can be seen that the polypropylene 411b infiltrated into the non-woven fabric 411a is continuously integrated.

[0108] [Experiment 4]

[0109] A heating wire with a diameter of 0.1 mm was buried between the first layer and the second layer of the four-layer structure to fabricate a PP-FRP member. The surface of the obtained PP-FRP member was observed. As a result, it was smooth without irregularities from the heating wire. For the obtained PP-FRP member, a current of 3 V and 4.5 A was passed through the wire, and as a result, conduction was carried out without problems.

[0110] It should be noted that this international application claims priority based on Japanese Patent Application No. 2022-165725 filed on October 14, 2022, and the entire content of Japanese Patent Application No. 2022-165725 is incorporated herein by reference.

[0111] Description of Reference Numerals

[0112] 10 Non-woven fabric; 20 Polypropylene; 30 Prepreg; 31 - 36 Prepreg; 40a, 40b Overlapped body; 41 Laminated body; 42 - 43 Formed body; 51 - 52 Fabric; 100 PP-FRP member; 111 - 114 Composite layer; 200 PP-FRP member; 211 - 212 Composite layer; 231 Wire; 300 PP-FRP member; 311 - 312 Composite layer; 331 Element; D1 Male mold; D2 Female mold; M1, M2 Nozzle part; R1 - R4 Roller.

Claims

1. A PP-FRP component, characterized in that, It has a plurality of composite layers, and the plurality of composite layers have a sheet-like fabric and polypropylene infiltrated into the meshes of the fabric and fixed therein. The plurality of composite layers are laminated, and the adjacent fabrics are in contact with each other. The polypropylene is filled in the meshes of the fabric and integrated.

2. The PP-FRP member according to claim 1, wherein The fabric constituting any of the plurality of composite layers is a non-woven fabric.

3. The PP-FRP member according to claim 1, characterized in that, One of the fabrics of the adjacent composite layers constituting the plurality of composite layers is a non-woven fabric, and the other is a woven fabric.

4. The PP-FRP member according to any one of claims 1 to 3, characterized in that, It further has a conductive material provided between the fabrics of the adjacent plurality of composite layers.

5. The PP-FRP member according to claim 4, wherein The melting point of the polypropylene is 160°C or lower.

6. The PP-FRP member according to any one of claims 1 to 3, characterized in that, The polypropylene contains 5 wt% or more and 30 wt% or less of a tackifier.

7. The PP-FRP member according to any one of claims 1 to 3, characterized in that, When hot pressing is performed at a temperature of 100°C or higher and 150°C or lower and a pressure of 2.5 MPa or lower, the rate of change in length before and after the hot pressing is 1% or lower.

8. A manufacturing method of a PP-FRP component, characterized in that, It includes: a step of overlapping a plurality of prepreg sheets having a non-woven fabric and polypropylene infiltrated into the non-woven fabric to form a first overlapping body; and a step of hot pressing the first overlapping body at a temperature of a specified temperature or higher and a pressure of a specified pressure or higher.

9. A manufacturing method of a PP-FRP component, characterized in that, It includes: a step of alternately overlapping a plurality of prepreg sheets having a woven fabric and polypropylene infiltrated into the woven fabric with a sheet-like fabric to form a second overlapping body; and a step of hot pressing the second overlapping body at a temperature of a specified temperature or higher and a pressure of a specified pressure or higher.

10. The manufacturing method of the PP-FRP member according to claim 8 or 9, characterized in that, The specified temperature is 100°C or higher and 150°C or lower, and the specified pressure is 1.5 MPa or higher and 2.5 MPa or lower.

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