Plate

Abstract

To provide a bottom board that has compressive strength comparable to that of wooden or plastic ones, but is light in weight, and attains enhanced usability and workability.SOLUTION: A bottom board has a pair of honeycomb boards. The honeycomb boards each have a honeycomb face with ribs forming a honeycomb structure on one principal face. The honeycomb boards are composed of fiber-reinforced plastic. The pair of honeycomb boards is disposed so that the honeycomb faces of the honeycomb boards are opposite each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a sole plate. [Background technology]

[0002] 2. Description of the Related Art Floor plates are laid on the bottom of various articles, vehicles, etc., and are used for the purposes of stabilizing articles, vehicles, etc. placed on the floor plates, preventing damage to floors and the ground, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-12173 A Summary of the Invention [Problem to be solved by the invention]

[0004] Outriggers are used to prevent mobile cranes, high-altitude work vehicles, pole-setting vehicles, and other work vehicles from falling over at construction sites, and when using the outriggers, a floor plate is laid between the outriggers and the ground. Patent Document 1 discloses a floor plate for an outrigger jack, characterized in that a float positioning recess having an outer shape that matches the outer shape of the jack's float is formed on either the front or back side of the floor plate body (see FIG. 1). Floor plates for outriggers are generally thick and made of wood or plastic in order to withstand high loads, and therefore have problems such as taking up space and being heavy, and are problematic in terms of usability and workability. Patent Document 1 does not mention or suggest such problems. The present disclosure is to provide a floor plate that has the same compressive strength as wooden or plastic floor plates, but is lightweight, and has excellent usability and workability. [Means for solving the problem]

[0005] The present disclosure includes the following aspects: [Section 1] A sole plate including a pair of honeycomb plates, The honeycomb plate has a honeycomb surface having ribs forming a honeycomb structure on one main surface, The honeycomb plate is made of fiber-reinforced plastic, The pair of honeycomb plates are arranged such that the honeycomb surfaces of each honeycomb plate face each other. [Section 2] Item 1. The base plate according to item 1, wherein the honeycomb structure is a hexagonal honeycomb structure. [Section 3] 3. The floor plate according to item 1 or 2, wherein the ratio of the ribs to the vertical projected area of ​​the honeycomb surface is 20% or more and 60% or less. [Section 4] 4. The floor plate according to any one of items 1 to 3, wherein the thickness of the rib is 3% to 30% of the maximum inner diameter of each cell of the honeycomb structure. [Section 5] 5. The floor plate according to any one of items 1 to 4, wherein the volume occupied by the ribs is 10% or more and 60% or less of the hollow volume of each cell of the honeycomb structure. [Section 6] The ratio of the ribs to the vertical projected area of ​​the honeycomb surface is 20% or more and 60% or less; The thickness of the rib is 3% or more and 40% or less of the maximum inner diameter of each cell of the honeycomb structure; 6. The floor plate according to any one of items 1 to 5, wherein the volume occupied by the ribs is 10% or more and 60% or less of the hollow volume of each cell of the honeycomb structure. [Section 7] 7. The floor plate according to any one of items 1 to 6, wherein the rib has a tapered shape with a draft angle of 0.5° or more and 30° or less. [Section 8] 8. The floor plate according to any one of items 1 to 7, wherein the tips of the ribs are rounded. [Section 9] Item 9. The floor plate according to any one of items 1 to 8, wherein the base of the rib is rounded. [Section 10] 10. The floor plate according to any one of items 1 to 9, wherein the honeycomb plate has a thickness of 50 mm or less, and the height of the ribs is 30% or more and 90% or less of the thickness of the honeycomb plate. [Section 11] Item 11. The floor plate according to any one of items 1 to 10, wherein the outermost surface of the floor plate has a plurality of grooves. [Section 12] Item 12. The floor plate according to any one of items 1 to 11, wherein the fiber-reinforced plastic is a glass fiber-reinforced thermoplastic resin. [Section 13] Item 13. The floor plate according to item 12, wherein the glass fiber reinforced thermoplastic resin is a glass mat reinforced thermoplastic resin. [Section 14] Item 14. The floor plate according to any one of items 1 to 13, wherein the fiber reinforced plastic is a carbon fiber reinforced thermoplastic resin. [Section 15] Item 15. The floor plate according to any one of items 1 to 14, wherein the honeycomb plate is a molded product of a random laminate of unidirectional prepregs. [Section 16] Item 16. The floor plate according to any one of items 1 to 15, comprising a middle plate, the middle plate being disposed between the pair of honeycomb plates. [Section 17] Item 17. The base plate according to any one of items 1 to 16, comprising a housing, the housing being disposed so as to surround a side surface of the honeycomb plate. [Section 18] Item 18. The underlayment according to item 16 or 17, comprising a handle, the handle being coupled to the midplate or the housing. [Section 19] Item 19. The floor plate according to any one of items 1 to 18, which is an outrigger floor plate. Effect of the Invention

[0006] The floor boards of the present disclosure have compressive strength equivalent to that of wooden or plastic floor boards, but are lightweight and have excellent usability and workability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, the sole plate according to one embodiment of the present disclosure will be described in more detail with reference to the drawings as necessary. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the description and to facilitate understanding by those skilled in the art.

[0008] The applicant provides the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and does not intend to limit the subject matter described in the claims. Note that various elements in the drawings are merely shown as schematic and illustrative elements for the understanding of the present disclosure, and the appearance, dimensional ratio, etc. may differ from the actual objects.

[0009] <Overall composition of floor plate> The floor plate of the present disclosure has a laminated structure and includes at least a pair of honeycomb plates, the pair of honeycomb plates being arranged so that their honeycomb surfaces face each other. The floor plate of the present disclosure may further include at least one selected from a rubber plate, a middle plate, a housing, a handle, etc. The floor plate of the present disclosure may include other members. Some or all of these members may be fixed to each other by adhesive, screws, etc.

[0010] The shape of the floor plate is a planar laminated structure such as a rectangle, a square, a diamond, or a circle, but is typically a rectangular laminated structure. The thickness of the floor plate may be 1 cm or more, 2 cm or more, 3 cm or more, 4 cm or more, or 5 cm or more. The thickness of the floor plate may be 10 cm or less, 8 cm or less, 6 cm or less, 4 cm or less, or 2 cm or less. From the viewpoint of weight reduction, a smaller thickness of the floor plate is preferable. The length and width are not particularly limited and may vary depending on the use of the floor plate, but may be, for example, about 20 cm to 80 cm x 20 cm to 80 cm.

[0011] <Honeycomb plate> The floor plate of the present disclosure includes a pair of honeycomb plates. The honeycomb plate has a honeycomb surface having ribs forming a honeycomb structure on one main surface, and the honeycomb plate is made of fiber-reinforced plastic, and the pair of honeycomb plates are arranged so that the honeycomb surfaces of each honeycomb plate face each other. By including a pair of honeycomb plates, the strength of the floor plate against static compression can be ensured, and at the same time, the weight of the floor plate can be reduced. In addition, by including a pair of honeycomb plates, unevenness in resistance to compression can be reduced throughout the floor plate. In conventional floor plates, the influence of localized load concentration due to the position of the load (e.g., the load of the outrigger) on the floor plate is large, which is problematic as it is prone to unevenness in resistance to compression. However, in the case of the floor plate of the present disclosure, it is easy to ensure similar strength against static compression at any position (e.g., even if the load position is shifted up, down, left, or right from the center of the floor plate).

[0012] The floor plate of the present disclosure includes a pair of honeycomb plates, but compared to the case where only one honeycomb plate is included, the height of the rib can be reduced, buckling of the rib can be suppressed, impact resistance can be increased, and compressive strength can be strengthened. In addition, by arranging a pair of honeycomb structures so that the honeycomb surfaces face each other, the floor plate has a vertically symmetrical structure, and there is no need to worry about the orientation of the surfaces, which is advantageous from the viewpoint of workability. Note that the floor plate may include one or more additional pairs of honeycomb plates. In this case, the compressive strength is increased, but from the viewpoint of weight reduction, it is preferable to include only a pair of honeycomb plates without including an additional honeycomb plate.

[0013] [Honeycomb surface] The honeycomb plate in the present disclosure has a honeycomb surface on one main surface.

[0014] The ribs form a honeycomb structure on the honeycomb surface. The honeycomb structure is a structure in which an assembly of a plurality of hollow cells (small rooms) is formed on a surface. The honeycomb structure is generally a hexagonal honeycomb structure in which the cell shape is hexagonal, but is not limited thereto. Examples of the cell shape include polygonal (e.g., 3 to 12 sided, specific examples of which are triangle, square, pentagon, heptagon, and octagon), perfect circle, ellipse, diamond, herringbone, and irregular shape. The cell shape may be one type, or a combination of multiple shapes and sizes. From the viewpoint of the compressive strength of the base plate, a polygonal honeycomb structure in which the cell shape is polygonal, and particularly a hexagonal honeycomb structure in which the cell shape is hexagonal, is preferred. A schematic diagram of a honeycomb plate having a honeycomb surface with a hexagonal honeycomb structure is shown in FIG. 3. The ribs of one honeycomb plate and the other honeycomb plate may be arranged so as to match in the vertical direction, or may be arranged so as to be shifted from each other.

[0015] The maximum inner diameter of each cell may be 0.5 cm or more, 1 cm or more, 1.5 cm or more, 2 cm or more, or 2.5 cm or more. The maximum inner diameter of each cell may be 10 cm or less, 8 cm or less, 6 cm or less, 4 cm or less, or 2 cm or less. By being in the above range, it is preferable from the viewpoint of the floor plate having a good combination of compressive strength and light weight.

[0016] The ratio of the ribs may be 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 45% or more, and preferably 30% or more, based on the vertical projected area of ​​the honeycomb surface. The ratio of the ribs is 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, or 35% or less, and preferably 50% or less, based on the vertical projected area of ​​the honeycomb surface. It is preferable that the ratio of the ribs is within the above range, from the viewpoint of providing the floor plate with a good combination of compressive strength and light weight.

[0017] The thickness of the rib may be 3% or more, 6% or more, 9% or more, 12% or more, 15% or more, 18% or more, 21% or more, or 24% or more, preferably 6% or more, relative to the maximum inner diameter of each cell of the honeycomb structure. The thickness of the rib may be 40% or less, 35% or less, 30% or less, 27% or less, 24% or less, 21% or less, 18% or less, 15% or less, 12% or less, or 9% or less, preferably 24% or less, relative to the maximum inner diameter of each cell of the honeycomb structure. Here, the thickness of the rib may be the maximum thickness of a cross section obtained by cutting the rib perpendicularly to the extension direction of the rib, and is typically the length of the bottom of the cross section. It is preferable that the thickness of the rib is within the above range from the viewpoint that the floor plate has good compressive strength and light weight. The thickness of the rib may be set to be thicker (for example, 9% or more, 12% or more, 15% or more, etc., relative to the maximum inner diameter of the cell). By setting the thickness to be thicker, it is possible to improve the ability of the fibers to conform to the matrix resin during molding, to increase the homogeneity of the material inside the rib, and to improve the compressive strength and durability of the sole plate. For example, when glass fibers (e.g., glass mat) are used as the fiber component, the thickness of the rib may be set to be thicker. The thickness of the rib may be changed depending on the strength of the material used (bending strength, tensile strength, elastic modulus, etc.). For example, when a high-strength material is used, the thickness of the rib may be set to be thin, and when a low-strength material is used, the thickness of the rib may be set to be thick.

[0018] The volume occupied by the ribs in each of the cells of the honeycomb structure may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more, and preferably 20% or more, relative to the hollow volume of the cells. The volume occupied by the ribs in each of the cells of the honeycomb structure may be 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less, and preferably 50% or less, relative to the hollow volume of the cells. It is preferable that the volume occupied by the ribs is in the above range, from the viewpoint of providing the floor plate with a good combination of compressive strength and light weight.

[0019] The rib may be tapered so that the thickness decreases from the base to the tip. The draft angle in the tapered shape may be 0.5° or more, 1.5° or more, 2.5° or more, 4.5° or more, 7.5° or more, or 10° or more. The draft angle in the tapered shape may be 35° or less, 30° or less, 25° or less, 20° or less, 17.5° or less, 15° or less, 10° or less, 7.5° or less, 5° or less, or 2.5° or less, and is preferably 15° or less, or 10° or less. By making the rib tapered, particularly a tapered shape having a draft angle in the above range, the occurrence of buckling of the rib can be suppressed, the compressive strength can be improved, and it is advantageous from the viewpoint of weight reduction. In addition, by making the rib tapered, a gap is easily formed between the molded product and the mold when demolding, and the molded product can be smoothly removed, which is advantageous from the viewpoint of productivity. A cross-sectional view of a honeycomb plate having a tapered rib is shown in FIG. 4.

[0020] The tips of the ribs may be chamfered. The chamfering may be R-chamfering or C-chamfering, and is preferably R-chamfering. Chamfering can prevent damage to the ribs and can improve the compressive strength and durability of the plate. As an example, a cross-sectional view of a honeycomb plate with R-chamfered tips of the ribs is shown in Figure 4. is shown in.

[0021] The base of the rib may be chamfered. The chamfering may be R chamfering or C chamfering, and is preferably R chamfering. Chamfering can prevent damage to the rib and improve the compressive strength and durability of the sole plate. Chamfering can also improve the ability of the fiber to follow the matrix resin during molding, improve the homogeneity of the material inside the rib, and improve the compressive strength and durability of the sole plate. For example, when glass fiber (e.g., glass mat) is used as the fiber component, the base of the rib may be chamfered. Both the tip and the base of the rib may be chamfered. As an example, a cross-sectional view (enlarged view of the rib part) of a honeycomb plate with R chamfering of the tip and base of the rib is shown in Figure 4-2.

[0022] The chamfer dimension (the radius of curvature in the case of an R-surface, the length of the cut edge in the case of a C-surface) at the tip of the rib may be 0.3 mm or more, 0.5 mm or more, 0.7 mm or more, 1.0 mm or more, 1.2 mm or more, or 1.5 mm or more, and is preferably 0.7 mm or more or 1.0 mm or more. The chamfer dimension may be 9.0 mm or less, 7.5 mm or less, 6.0 mm or less, 4.5 mm or less, 4.0 mm or less, 3.0 mm or less, 2.5 mm or less, 2.0 mm or less, or 1.5 mm or less, and is preferably 3.0 mm or less, and more preferably 2.0 mm or less. The above range is suitable from the viewpoint of the compressive strength and durability of the floor plate.

[0023] The chamfer dimension at the base of the rib (the radius of curvature in the case of an R-surface, or the length of the cut edge in the case of a C-surface) may be 0.5 mm or more, 1.0 mm or more, 1.5 mm or more, 2.0 mm or more, 2.5 mm or more, or 3.0 mm or more, and is preferably 1.5 mm or more or 2.5 mm or more. The chamfer dimension at the base of the rib may be 9.0 mm or less, 7.5 mm or less, 6.0 mm or less, 4.5 mm or less, 4.0 mm or less, 3.5 mm or less, or 3.0 mm or less, and is preferably 4.5 mm or less, and more preferably 3.5 mm or less. The above ranges are suitable from the viewpoint of the compressive strength and durability of the floor plate.

[0024] The thickness of the honeycomb plate may be 1 mm or more, 3 mm or more, 5 mm or more, 8 mm or more, or 10 mm or more. The thickness of the honeycomb plate may be 50 mm or less, 40 mm or less, 30 mm or less, 25 mm or less, 20 mm or less, or 15 mm or less. Here, the thickness of the honeycomb plate is the sum of the thickness of the substrate of the honeycomb plate and the height of the ribs. The smaller the thickness of the honeycomb plate, the more preferable it is from the viewpoint of weight reduction.

[0025] The height of the rib may be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, or 80% or more of the thickness of the honeycomb plate. The height of the rib may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, or 40% or less of the thickness of the honeycomb plate. It is preferable that the height of the rib is equal to or more than the above lower limit from the viewpoint of weight reduction, and it is preferable that the height of the rib is equal to or less than the above upper limit from the viewpoint of preventing buckling of the rib and improving the compressive strength.

[0026] The non-honeycomb surface (the main surface not having ribs) may be flat, but the non-honeycomb surface (particularly the non-honeycomb surface constituting the outermost surface of the floor plate) may have a plurality of grooves. The shape of the plurality of grooves is not limited, but is typically striped or mesh-like. A schematic diagram of a floor plate having a plurality of mesh-like grooves is shown in FIG. 2. The groove spacing between the grooves may be 3 mm or more, 5 mm or more, 8 mm or more, or 10 mm or more. The groove spacing between the grooves may be 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, or 10 mm or less. The groove width is not limited, but may be, for example, 0.1 mm or more, 0.3 mm or more, 0.5 mm or more, or 0.7 mm or more, and may be 5 mm or less, 3 mm or less, or 1 mm or less. By having a plurality of grooves on the non-honeycomb surface, it is possible to increase the grip force and prevent the floor plate from slipping or shifting when used.

[0027] [Fiber reinforced plastics] The honeycomb plate is made of fiber-reinforced plastic, which is a composite material that contains a thermosetting resin and / or a thermoplastic resin as a matrix component and further contains fibers such as carbon fibers and glass fibers in the resin.

[0028] [Matrix resin component] Examples of the matrix resin component in fiber reinforced plastics include thermoplastic resins such as thermoplastic epoxy resins, polyolefins (polyethylene, polypropylene, etc.), polyhalogenated olefins, polystyrene, polyvinyl acetate, polyurethane, Teflon (registered trademark), ABS resins, AS resins, polyamides, polyacetals, polycarbonates, polyethers, polyesters, thermoplastic polyimides, polyamide resins, polyamideimide resins, polyester resins, and thermoplastic acrylic resins; and thermosetting resins such as thermosetting epoxy resins, phenolic resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, urethane resins, thermosetting polyimides, and thermosetting acrylic resins. As the matrix resin component in the present disclosure, thermoplastic resins such as epoxy resins (particularly the polymer (x) described below) and polyolefins (particularly polypropylene) can be used because they have high moldability and can be excellent in productivity. For example, when carbon fibers are used as the fiber component, epoxy resins may be used as the matrix resin component, and when glass fibers are used as the fiber component, polyolefins may be used as the matrix resin component.

[0029] [Fiber components] Examples of fibers in fiber-reinforced plastics include organic fibers such as aramid fibers, polyethylene fibers, and polyparaphenylenebenzoxazole (PBO) fibers; inorganic fibers such as glass fibers, carbon fibers, silicon carbide fibers, alumina fibers, Tyranno fibers, basalt fibers, and ceramic fibers; metal fibers such as stainless steel fibers and steel fibers; and other reinforcing fibers using boron fibers, natural fibers, and modified natural fibers. As these reinforcing fibers, reinforcing fibers composed of several thousand or more filaments are preferable. For example, reinforcing fibers composed of 3,000 to 60,000 filaments are preferably used in producing unidirectional prepregs for producing fiber-reinforced thermoplastic resin sheets. From the viewpoint of the strength of the floor plate in the present disclosure, it is more preferable that the reinforcing fibers are glass fibers or carbon fibers. The fibers may be one type of reinforcing fiber, or two or more types of fibers may be used in combination.

[0030] Although there is no particular limitation on the presence or absence of twist in the fibers, from the viewpoint of easily increasing the penetration of the matrix resin, fibers with little or no twist are preferred. From the same viewpoint, the number of twists of the fibers is preferably 1 turn / m or less, more preferably 0.5 turns / m or less, and even more preferably 0.3 turns / m or less.

[0031] From the viewpoint of combining strength and lightness, the fiber reinforced plastic is preferably a carbon fiber reinforced plastic or a glass fiber reinforced plastic.

[0032] The carbon fiber used in the present disclosure may be a pitch-based carbon fiber or a PAN-based carbon fiber. From the viewpoint of handling, the carbon fiber is preferably a PAN-based carbon fiber.

[0033] Carbon fibers are often wound around a cylindrical bobbin with a certain traverse width. The filament diameter of one carbon fiber is usually 5 to 8 μm, and a fiber bundle (carbon fiber tow) in which a plurality of carbon fibers are assembled in a flat shape with a predetermined number of filaments (specifically, 1000 (1K), 3000 (3K), 6000 (6K), 12000 (12K), 15000 (15K), 18000 (18K), 24000 (24K), 30000 (30K), 60000 (60K)) is preferably used. The number of filaments of the carbon fiber may be appropriately changed depending on the properties of the fiber-reinforced plastic (for example, the desired width and thickness of the opened carbon fiber or unidirectional prepreg), but from the viewpoint of productivity, it is preferably 3000 to 60000, more preferably 6000 to 24000. It is preferable that the number of filaments is equal to or less than the above upper limit because this can suppress the generation of voids in the fiber-reinforced plastic, and it is preferable that the number of filaments is equal to or more than the above lower limit because this can easily suppress fluffing due to breakage of single filaments during fiber spreading and cracking of the fiber-reinforced plastic.

[0034] Examples of glass fibers used in the present disclosure include E glass, AR glass, C glass, D glass, H glass, S glass, T glass, M glass, and NE glass.

[0035] The diameter of the glass fiber may be 0.5 μm or more, 1 μm or more, 5 μm or more, 10 μm or more, or 25 μm or more, and may be 100 μm or less, 75 μm or less, 25 μm or less, or 10 μm or less. The above ranges are preferable from the viewpoints of fiber dispersion and compressive strength of the floor plate.

[0036] The glass fiber length may be 1 mm or more, 3 mm or more, 5 mm or more, 10 mm or more, 20 mm or more, 30 mm or more, 50 mm or more, 70 mm or more; 200 mm or less, 150 mm or less, 100 mm or less, 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, 3 mm or less, or 1 mm or less. The glass fiber may be either a long fiber type (e.g., 5 mm or more, 30 mm or more, or 50 mm or more) or a short fiber type (e.g., 10 mm or less, 3 mm or less, 1 mm or less), with the long fiber type being preferred from the viewpoint of compressive strength. The long fiber can be produced by melting and drawing glass to form it into a fiber shape, and the short fiber type can be produced by cutting the long fiber type. In consideration of the environment and / or cost reduction, a part or all of the glass fiber used may be a recycled material (e.g., glass fiber in which short fiber and long fiber are mixed).

[0037] The fiber volume fraction Vf in the fiber reinforced plastic is controlled to be preferably 10 to 80%, more preferably 15 to 60%, even more preferably 20 to 55%, even more preferably 25 to 45%, even more preferably 30 to 45%, even more preferably 35 to 45%, and particularly preferably 37.5 to 42.5%. The above ranges are preferable from the viewpoints of moldability of the fiber reinforced plastic and strength of the molded product.

[0038] [Fiber reinforced thermoplastic resin] Since fiber reinforced plastics have high moldability and can be excellent in productivity, they may be fiber reinforced thermoplastic resins. Preferably, they may be carbon fiber reinforced thermoplastic resins (e.g., carbon fiber reinforced epoxy resins) or glass fiber reinforced thermoplastic resins (e.g., glass mat reinforced polyolefin resins) because they have good strength, lightness, and moldability.

[0039] The honeycomb board may be a molded body of fiber-reinforced thermoplastic resin, for example, a molded body of a random laminate of unidirectional prepregs or a molded body of glass mat reinforced thermoplastic resin. For example, in the process of manufacturing a honeycomb board, a fiber-reinforced plastic is subjected to a molding process to form a honeycomb board shape, and the fiber-reinforced plastic subjected to the molding process may be a random laminate of unidirectional prepregs (particularly, a random laminate of tape-shaped unidirectional prepregs. Here, the tape-shaped unidirectional prepregs are prepregs that contain opened reinforcing fibers and have one directionality.) or a glass mat reinforced thermoplastic resin.

[0040] [Random laminate of unidirectional prepregs] In the following, a fiber reinforced thermoplastic resin sheet, which is a random laminate of unidirectional prepregs, will be described as an example of a fiber reinforced plastic. The number of layers of unidirectional prepregs per unit thickness of the fiber reinforced thermoplastic resin sheet of the present disclosure is preferably 6 layers / mm or more, more preferably 8 layers / mm or more, even more preferably 10 layers / mm or more, and particularly preferably 11 layers / mm or more. When the number of layers of unidirectional prepregs per unit thickness is equal to or more than the above lower limit, the strength of the molded body obtained from the resin sheet of the present disclosure is easily increased. In addition, the number of layers of unidirectional prepregs per unit thickness is preferably 40 layers / mm or less, more preferably 25 layers / mm or less, and particularly preferably 20 layers / mm or less. When the number of layers of unidirectional prepregs per unit thickness is equal to or less than the above upper limit, the isotropy of the fiber reinforced thermoplastic resin sheet is easily improved. The number of layers of unidirectional prepregs per unit thickness of the fiber reinforced thermoplastic resin sheet of the present disclosure is measured visually from an image obtained by observing the cross section of the fiber reinforced thermoplastic resin sheet using an electron or optical microscope.

[0041] The void ratio of the fiber reinforced thermoplastic resin sheet of the present disclosure, preferably having an average thickness of 2 mm, is preferably 0 to 1 vol%, more preferably 0 to 0.5 vol%, as measured according to JIS-7075. A fiber reinforced thermoplastic resin sheet having such a low void ratio has very good moldability, and the mechanical strength of the obtained molded article is also easily increased.

[0042] The mechanical strength such as tensile strength of the fiber reinforced thermoplastic resin sheet of the present disclosure varies depending on the type of reinforcing fiber contained in the fiber reinforced thermoplastic resin sheet, the type of resin, the thickness of the sheet, the fiber volume content (Vf), etc., and can be appropriately selected and set according to the strength desired for the molded body obtained from the fiber reinforced thermoplastic resin sheet. From the viewpoint of ease of use in fields such as secondary structural materials of automobiles in which the fiber reinforced thermoplastic resin sheet of the present disclosure is suitably used, the bending strength measured according to ASTM D790 of the fiber reinforced thermoplastic resin sheet of the present disclosure is preferably 300 MPa or more, more preferably 400 MPa or more, even more preferably 440 MPa or more, particularly preferably 450 MPa or more, and most preferably 460 MPa or more. The above bending strength may be an average bending strength. The fiber reinforced thermoplastic resin sheet of the present disclosure is capable of achieving strength, moldability, and appearance quality even in fields where high bending strength is required as described above. From the same viewpoint, the flexural modulus of the fiber-reinforced thermoplastic resin sheet of the present disclosure measured according to ASTM D790 is preferably 25 GPa or more, more preferably 28 GPa or more, the tensile strength measured according to JIS K 7164 (ISO527-4) is preferably 200 MPa or more, more preferably 250 MPa or more, and the tensile modulus is preferably 25 GPa or more, more preferably 28 GPa or more. The above physical property values ​​are preferably physical property values ​​in a reinforced fiber thermoplastic resin sheet having an average thickness of, for example, 2 mm and a fiber volume content (Vf) of 40%. The bending properties and tensile properties are measured using a test machine such as a universal testing machine manufactured by Shimadzu Corporation. The bending strength may be measured, for example, by the method described in the examples.

[0043] In a preferred embodiment of the present disclosure, when the average content of reinforcing fibers in the thickness direction in each unidirectional prepreg contained in the fiber-reinforced thermoplastic resin sheet is set to a predetermined value or less, it is easy to reduce the portion where the fiber orientation is locally excessive, and as a result, it is easy to uniformly transfer stress in a direction different from the fiber axis direction via the fibers. When the fiber-reinforced thermoplastic resin sheet of the present disclosure has the above characteristics, the strength of the fiber-reinforced thermoplastic resin sheet in all directions is improved. Therefore, in this case, when a molded article is produced from the fiber reinforced thermoplastic resin sheet of the present disclosure, the moldability is improved, and it becomes easier to produce an isotropic molded article with less variation in strength.

[0044] The shape of the fiber-reinforced thermoplastic resin sheet of the present disclosure may be appropriately changed according to the shape of the desired molded product, and is not particularly limited.

[0045] (Unidirectional prepreg) The tape-like unidirectional prepreg may be a prepreg containing opened reinforcing fibers, the fibers having unidirectionality. In the prepreg contained in the fiber-reinforced thermoplastic resin sheet of the present disclosure, the unidirectionality of the fibers can be evaluated as follows. First, the midpoint of the width is obtained at each of both cut ends of the prepreg cut to have a predetermined length in the fiber direction (for example, 150 mm in the fiber direction), and the midpoint of one end is connected to the midpoint of the other end, and this line is used as a reference line. For the prepreg on one side of the reference line, the length in the width direction (a length that is about half the width length, hereinafter also referred to as "half width") is measured at at least 10 points along the fiber direction. The coefficient of variation calculated from the average value of the half widths obtained at at least 10 points and the standard deviation is preferably 10% or less, more preferably 9% or less, even more preferably 7% or less, and particularly preferably 5% or less.

[0046] In this specification, the average number of reinforcing fibers in the thickness direction, the average reinforcing fiber content in the width direction, the coefficient of variation of the width length (CV value), and the average length in the fiber direction for the unidirectional prepreg before lamination do not basically change before and after the fiber-reinforced thermoplastic resin sheet is produced from the unidirectional prepreg. Therefore, for these, the description of the preferred ranges, etc. for the unidirectional prepreg before lamination also applies to the unidirectional prepreg in the state of being included in the fiber-reinforced thermoplastic resin sheet of the present disclosure.

[0047] The opened reinforcing fibers contained in the fiber-reinforced thermoplastic resin sheet of the present disclosure are contained in each unidirectional prepreg randomly laminated in the fiber-reinforced thermoplastic resin sheet of the present disclosure. In the opened reinforcing fibers contained in each unidirectional prepreg, the average number of reinforcing fibers in the thickness direction is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, even more preferably 8 or less, even more preferably 7 or less, and particularly preferably 6 or less. The lower limit of the average number of fibers contained in the thickness direction is preferably as small as possible from the viewpoint of easily increasing the penetration of the resin, and is not particularly limited, but is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. When the average number of fibers contained in the thickness direction is equal to or less than the above upper limit, the compound serving as the raw material of the polymer contained in the unidirectional prepreg (for example, a bisphenol A type epoxy compound and a bisphenol compound represented by formula (1), and optionally a compound having a reactive group that is one epoxy group or hydroxyl group in one molecule) is easily impregnated sufficiently uniformly into the fibers, and gaps (voids) where the resin is not impregnated between the fibers are less likely to occur. If the prepreg contains voids, the voids remain in the random laminate (fiber-reinforced thermoplastic resin sheet) produced from the prepreg, and further remain in the molded body produced from the sheet. As a result, sufficient strength of the molded body may not be obtained. Alternatively, in order to achieve sufficient strength of the molded body, severe conditions such as applying high temperature and / or high pressure or applying a long press time are required so that the voids are removed in the process of producing a random laminate (fiber-reinforced thermoplastic resin sheet) or a molded product from the prepreg. Such severe conditions are not preferable because they cause deterioration of the resin and a decrease in production efficiency. In addition, when the average content in the thickness direction is equal to or less than the above upper limit, it is easy to reduce the parts where the fiber orientation is locally excessive, so that stress is easily transmitted in a direction different from the fiber axis direction through the fibers, and as a result, it is easy to fully utilize the strength that the fibers originally have.

[0048] When the opened reinforcing fibers have the above configuration, the average number of reinforcing fibers in the thickness direction of each unidirectional prepreg contained in the fiber-reinforced thermoplastic resin sheet of the present disclosure can also be set to the above upper limit or lower limit. Therefore, the average number of reinforcing fibers in the thickness direction of the unidirectional prepreg contained in the fiber-reinforced thermoplastic resin sheet of the present disclosure is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, even more preferably 8 or less, even more preferably 7 or less, and particularly preferably 6 or less. In addition, the lower limit value of the average number in the thickness direction is not particularly limited, and is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more, from the viewpoint of easily increasing the penetration of the resin.

[0049] The number of reinforcing fibers in the thickness direction contained in a unidirectional prepreg is measured by embedding a cross section of the prepreg cut in the thickness direction in resin or the like, observing the cross section using an electron microscope or the like, and counting the number of fibers present in the thickness direction in the obtained image. In this way, the number of fibers present in the thickness direction is counted in at least five cross-sectional images, and the average value is taken as the average number of reinforcing fibers in the thickness direction. In the above cross-sectional observation, in order to minimize the effect of external forces on the prepreg during cutting, both sides of the prepreg are, for example, covered with a rigid material such as metal. The prepreg may be sandwiched between plates and cut to observe the cross section. When the unidirectional prepreg has a certain length (for example, when it is in the form of a tape wound on a bobbin), the above-mentioned at least five points may be measured at at least five points spaced at intervals of, for example, about 50 cm in the fiber axis direction, or when the unidirectional prepreg is in the form of a cut tape, at least five prepregs may be arbitrarily taken out of the cut prepregs and measured. When multiple points are measured, the multiple points may be measured in the same manner as above.

[0050] The coefficient of variation (CV value) of the number of reinforcing fibers contained in the unidirectional prepreg in the thickness direction is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. In the present disclosure, the coefficient of variation is calculated by measuring the number of reinforcing fibers contained in each unidirectional prepreg in the thickness direction at least at 10 points, and using the average value and standard deviation obtained from the results, the coefficient of variation (CV value) = standard deviation / average value × 100 (%). When the coefficient of variation of the number of reinforcing fibers contained in the thickness direction is equal to or less than the above upper limit, lamination unevenness is unlikely to occur when a random laminate is produced from the unidirectional prepreg, and the isotropy of the fiber-reinforced thermoplastic resin sheet of the present disclosure is easily ensured.

[0051] The average reinforcing fiber content density in the width direction of the opened reinforcing fibers contained in the unidirectional prepreg calculated from formula (2) (hereinafter also referred to as "average content density A") is preferably 150 to 2,000 fibers / mm, more preferably 500 to 1,500 fibers / mm, and even more preferably 700 to 1,000 fibers / mm. When the average reinforcing fiber content density in the width direction is equal to or less than the upper limit, voids are unlikely to occur inside the prepreg when the raw material compound is impregnated and then solidified, and the mechanical strength of the fiber-reinforced thermoplastic resin sheet produced from this unidirectional prepreg is easily increased. In addition, when the average reinforcing fiber content density in the width direction is equal to or more than the lower limit, it is easy to prevent the occurrence of cracks in the prepreg and to increase the strength of the fiber-reinforced thermoplastic resin sheet of the present disclosure.

[0052] By setting the average content density in the width direction per unidirectional prepreg within the above range, the unidirectional prepreg is less likely to crack even though it is a thin layer, and voids are easily reduced. By producing the fiber-reinforced thermoplastic resin sheet of the present disclosure using such a unidirectional prepreg, it is easy to improve the moldability and strength of the sheet, and also to improve the quality of the molded body produced from the fiber-reinforced thermoplastic resin sheet of the present disclosure. The average density of the reinforcing fibers in the width direction is calculated by the formula (2). The method for measuring the average number of reinforcing fibers in the thickness direction in the formula (2) is as described above. In addition, (1 / single fiber diameter of reinforcing fiber [mm]) in the formula (2) represents the number of reinforcing fibers that can be contained in a unit layer per 1 mm in the width direction. TIFF0007672725000001.tif14163

[0053] When manufacturing a unidirectional prepreg, a restraining agent may be attached to the opened reinforcing fibers. By attaching the restraining agent, it is easy to increase the restraint of the width of the opened reinforcing fibers, and it is also possible to suppress cracks that may occur when manufacturing the unidirectional prepreg. The amount of the restraining agent attached is preferably 0 to 0.8 mass% based on the mass of the reinforcing fibers, and more preferably 0.3 to 0.5 mass%, in consideration of the effect on the deterioration of the physical properties of the finally obtained prepreg. It is preferable to set the amount of the restraining agent attached to the above lower limit or more, since it is possible to increase the restraint of the width of the opened reinforcing fibers. By setting the amount of the restraining agent attached to the above range, it is easy to suppress the deterioration of the physical properties of the molded body obtained from the prepreg and cracks that may occur when manufacturing the unidirectional prepreg. The type of restraining agent used is not particularly limited, but emulsified epoxy resins, emulsified modified polyolefin resins, etc. are preferably used.

[0054] (Polymer(x)) The unidirectional prepreg and the fiber-reinforced thermoplastic resin sheet may contain opened reinforcing fibers and a polymer (x). The polymer (x) is at least a polymer represented by the formula (1): TIFF0007672725000002.tif23167 [wherein n represents an integer of 1 to 4] and a bisphenol compound selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol E and bisphenol P.

[0055] Weight average molecular weight M of polymer (x) wThe weight average molecular weight M of the polymer (x) is 25,000 or more, preferably 25,000 to 140,000, more preferably 26,000 to 100,000, further preferably 27,000 to 80,000, and further more preferably 28,000 to 75,000. w If the weight average molecular weight M is less than 25,000, the strength of the resulting molded article cannot be sufficiently increased. w When the weight average molecular weight M is equal to or greater than the above lower limit, the mechanical strength of the fiber-reinforced thermoplastic resin sheet is easily increased, and a molded product having sufficient mechanical strength is easily obtained. w When the ratio M is equal to or less than the upper limit, the moldability of the fiber-reinforced thermoplastic resin sheet of the present disclosure is easily improved. w When the above condition is satisfied, it is preferable because it is easy to improve both the physical properties such as mechanical strength of the molded product obtained from the fiber-reinforced thermoplastic resin sheet and the moldability of the fiber-reinforced thermoplastic resin sheet. In addition, it is easy to improve the appearance quality of the obtained molded product. From the viewpoint of moldability, it is preferable that the weight average molecular weight M w From the viewpoint of the mechanical strength of the fiber-reinforced thermoplastic resin sheet and the molded product, the weight-average molecular weight M of the polymer (x) may be 50,000 or less, 40,000 or less, etc. w may be 30,000 or more, 40,000 or more, etc. When a molded product is produced from a fiber-reinforced thermoplastic resin sheet by pressing or the like, the fiber-reinforced thermoplastic resin sheet may be heated. If the fiber-reinforced thermoplastic resin sheet in a heated state is prone to sagging, the conveyability becomes poor and the handleability of the sheet decreases. From the viewpoint of easily improving the moldability and handleability of the sheet, the weight-average molecular weight M w is preferably 35,000 to 140,000, more preferably 40,000 to 100,000, and further preferably 40,000 to 80,000.

[0056] Number average molecular weight M of polymer (x) n is preferably 8,000 to 20,000. n If is within the above range, M w / M nSince the dispersion ratio is small, it is easy to suppress the variation in the mechanical strength of the molded body.

[0057] Weight average molecular weight M of polymer (x) w and number average molecular weight M n The molecular weight distribution M w / M n is preferably 3 to 10, more preferably 3.1 to 8, even more preferably 3.2 to 7, still more preferably 3.2 to 6, and particularly preferably 3.2 to 5. w / M n When the thickness is within the above range, the variation in mechanical strength of the molded article is easily suppressed.

[0058] In this specification, the weight average molecular weight and number average molecular weight of the polymer are measured using a thermoplastic resin (e.g., polymer (x)) contained in the fiber reinforced thermoplastic resin sheet as a measurement sample by gel permeation chromatography (GPC). Specific measurement conditions may be appropriately changed depending on the type of resin, but may be as follows.

[0059] In measuring the weight average molecular weight and number average molecular weight of the thermoplastic resin contained in the fiber reinforced thermoplastic resin sheet, the thermoplastic resin is extracted from each fiber reinforced thermoplastic resin sheet using tetrahydrofuran, the resin concentration of the extract is adjusted to 1 mass%, a measurement sample is obtained, and the measurement may be performed under the following conditions. Column: GPC KF803L (Showa Denko) Column temperature: 40℃ Eluent: Tetrahydrofuran Flow rate: 1ml / min Detector: SPD-M20A (Shimadzu Corporation) Molecular weight standards: Standard polystyrene

[0060] For example, in the step (b) described below, when the bisphenol A type epoxy compound and the bisphenol compound used as raw materials are impregnated at a molar ratio of preferably 40:60 to 60:40, more preferably 45:65 to 55:45, and further preferably 48:52 to 52:48, and at the same time, a compound having one reactive group per molecule is impregnated, the polymer (x) The rate of change in weight-average molecular weight before and after heating (ratio M) can be easily adjusted to within a specified range.

[0061] The polymer (x) is an in-situ polymerization type polymer, and is further polymerized in the process of producing a molded product from a thermoplastic resin sheet. Specifically, for example, further polymerization of the polymer (x) and the bisphenol compound still contained in the thermoplastic resin sheet proceeds. For this reason, it is easy to increase the strength of the thermoplastic resin sheet, the moldability when producing a final molded product, the strength of the molded product, etc. In particular, in a fiber-reinforced thermoplastic resin sheet having an in-situ polymerization type thermoplastic resin as the matrix resin, when a molded product is produced by pressing with a mold, the polymerization of the thermoplastic resin may proceed at a high polymerization rate even under pre-heating conditions, so that sufficient moldability and shapeability may not be obtained. In addition, in a continuous manufacturing process of molded products, depending on the elapsed time from the start of production, particularly the difference in thermal history, a molded product of constant quality in terms of moldability and / or strength may not be obtained. By adjusting the rate of change (ratio M) of the weight average molecular weight before and after heating of the polymer (x) contained in the fiber-reinforced thermoplastic resin sheet of the present disclosure to be within a predetermined range, the above-mentioned problems are solved, and the moldability and strength of the fiber-reinforced thermoplastic resin sheet are improved.

[0062] The polymer (x) contained in the fiber-reinforced thermoplastic resin sheet of the present disclosure is a polymer of at least a bisphenol A type epoxy compound and a bisphenol compound used as a raw material, and the molecular weight of the bisphenol A type epoxy compound used as a raw material before polymerization is usually 2,000 or less. The bisphenol A type epoxy compound is produced by a condensation reaction of bisphenol A and epichlorohydrin. Conventionally, bisphenol A type epoxy resin is a representative resin as a thermosetting synthetic resin, and is three-dimensionally cured by reacting with various curing agents to obtain a cured resin with various properties. On the other hand, the bisphenol A type epoxy compound used in the present disclosure has epoxy groups, which are functional groups, only at both ends of the molecular chain, as shown in formula (1), and the repeating unit n of the molecular chain is 1 to 4. Note that when n is 1 to 4, the molecular weight of the bisphenol A type epoxy compound is 594 to 1416. Bisphenol A, which is one of the bisphenol compounds used as a raw material, is synthesized by the reaction of phenol and acetone, and is represented by formula (3): It has a structure represented by TIFF0007672725000003.tif2091. As shown in formula (3), bisphenol A has a phenolic hydroxyl group, which is a functional group, at both ends of the molecule, and has a molecular weight of 228. Note that, like bisphenol A, other bisphenol compounds in the present disclosure, bisphenol F, bisphenol S, bisphenol B, bisphenol E, and bisphenol P, all have a phenolic hydroxyl group, which is a functional group, at both ends of the molecule, and have a molecular weight of 200 to 346. In this way, by using a low molecular weight raw material, the raw material compound is easily permeated between the reinforcing fibers opened during the prepreg production, and the obtained prepreg is in a state where the resin is uniformly impregnated (full impregnation) without containing voids between the fibers. From the same viewpoint, it is preferable to polymerize after impregnating the fibers with the raw material compound in the prepreg production process.

[0063] The functional group of the bisphenol A type epoxy compound represented by formula (1) used as a raw material is an epoxy group, and the functional group of the bisphenol compound represented by formula (3) is a phenolic hydroxyl group. Therefore, these polymerization reactions proceed sequentially by electrophilic substitution reaction between the epoxy group in formula (1) and the phenolic hydroxyl group in formula (3). In both compounds, since functional groups are present at both ends, for example, when the mixture of raw material compounds is impregnated and solidified into the opened reinforcing fibers in the raw material impregnation process and sheet manufacturing process, and when the random laminate is heated and press molded, the obtained polymer becomes linear. As a result, the polymer of the above raw material compound contained in the unidirectional prepreg and the fiber reinforced thermoplastic resin sheet of the present disclosure has thermoplastic properties.

[0064] Such a polymer is easy to handle in the manufacturing process of unidirectional prepreg. Specifically, the raw materials, bisphenol A type epoxy compound and bisphenol compound, are polymerized sequentially through the manufacturing process of prepreg and sheet. This reaction is an irreversible reaction, and by-products are not eliminated as in condensation reactions (e.g., dehydration reactions). This allows the prepreg and sheet to be manufactured using open-system equipment. In addition, since the raw material compounds used in manufacturing prepreg have low molecular weights and low viscosity, these raw materials can be easily impregnated into fibers even at room temperature. Furthermore, since the raw materials can be easily impregnated, the tension applied to the reinforcing fibers can be suppressed in the prepreg manufacturing process described below, and the fibers can be processed gently by preventing fluffing and cutting of the fibers, thereby stabilizing the quality of the prepreg. Here, when manufacturing a unidirectional prepreg by impregnating a high molecular weight resin, it is difficult to sufficiently impregnate between the fibers due to the high viscosity of the resin, and voids tend to remain inside the prepreg, causing a decrease in strength in the sheet physical properties. In addition, the amount of resin that can be impregnated is also limited, making it less versatile in prepreg production.

[0065] The polymer (x) obtained by the polymerization reaction of at least a bisphenol A type epoxy compound and a bisphenol compound contained in the fiber reinforced thermoplastic resin sheet of the present disclosure is an in-situ polymerization type thermoplastic resin and is an amorphous resin. In addition, since it has a predetermined range of ratio M while maintaining the glass transition temperature of the resin itself, excessive polymerization is suppressed and the compatibility between the reinforcing fiber and the matrix resin is good. Therefore, pressing at a low viscosity is possible in the molding temperature range of the fiber reinforced thermoplastic resin sheet of the present disclosure, and a molded body having good moldability, excellent surface transferability to a mold, and excellent appearance quality can be obtained.

[0066] The fiber-reinforced thermoplastic resin sheet of the present disclosure may contain any additive other than those described above. Examples of additives include organic solvents, reaction accelerators, monofunctional epoxy compounds, coupling agents, curing agents (reaction accelerators), pigments, defoamers, antifungal agents, and deterioration inhibitors. When these additives are added, the amount may be appropriately changed depending on the purpose of addition. For example, a reaction accelerator may be used to promote the polymerization reaction of the above raw material compounds. The raw material compounds, bisphenol A type epoxy compounds and bisphenol compounds, are polymerized sequentially by electrophilic substitution reaction as described above. Therefore, when polymerizing these, it is preferable to use a basic phosphorus-based or amine-based reaction accelerator that easily promotes electrophilic substitution reaction, and it is particularly preferable to use an organic phosphorus compound from the viewpoint of production speed.

[0067] As the organic phosphorus compound, triphenylphosphine, tri-para-tolylphosphine, diphenylcyclohexylphosphine, tricyclohexylphosphine, ethyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, 1,4-bisdiphenylphosphinobutanone, and the like are suitably used.

[0068] From the viewpoint of easily adjusting the weight-average molecular weight of the polymer of the above raw material compounds to the above preferred range, it is preferable to use the reaction accelerator in an amount of 2 to 3 parts by mass per 100 parts by mass of the above polymer contained in the unidirectional prepreg.

[0069] The monofunctional epoxy compound may be added from the viewpoint of suppressing excessive polymerization. The monofunctional epoxy compound is not particularly limited, but may be, for example, an aromatic monofunctional epoxy compound (particularly an alkylphenol monofunctional epoxy compound), an aliphatic hydrocarbon monofunctional epoxy compound, etc. In step (b), one type of monofunctional epoxy compound may be used, or two or more types of monofunctional epoxy compounds may be used in combination.

[0070] (Method of manufacturing fiber reinforced thermoplastic resin sheet) Next, an example of the manufacturing method of the fiber reinforced thermoplastic resin sheet of the present disclosure will be described.

[0071] The method for producing a fiber reinforced thermoplastic resin sheet of the present disclosure includes: (a) a step of opening reinforcing fibers; (b) The spread reinforcing fibers are subjected to the reaction of the formula (1): TIFF0007672725000004.tif23166 [wherein n represents an integer of 1 to 4] a step of impregnating a bisphenol A type epoxy compound represented by the formula (I) with a bisphenol compound selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol E and bisphenol P, and at least one compound having one reactive group in one molecule, wherein the reactive group is a hydroxyl group or an epoxy group; (c) heating the reinforcing fibers impregnated with the compound to polymerize the compound impregnated in the reinforcing fibers until the weight average molecular weight of the resulting polymer is 5,000 to 25,000, thereby obtaining a unidirectional prepreg; (d) randomly laminating the unidirectional prepregs to obtain a laminate; and (e) A step of heating the laminate at a temperature of 100 to 200°C to obtain a fiber-reinforced thermoplastic resin sheet. may include at least

[0072] The reinforcing fiber used in the above step (a) is not particularly limited, but is an unopened reinforcing fiber, usually called "raw yarn." Such reinforcing fiber is wound around a bobbin, which is a cylindrical tube, with a certain traverse width, and is often unwound for use.

[0073] Here, normally, if the raw yarn wound in traverse on a cylindrical bobbin is simply unwound, the fiber bundle will be sent out in a meandering state with respect to the traveling direction. From the viewpoint of easily obtaining the fiber-reinforced thermoplastic resin sheet of the present disclosure described above, it is preferable to use an apparatus that eliminates the traverse caused by the raw yarn and sends out the fiber bundle straight with respect to the traveling direction without meandering.

[0074] In step (a), the tension applied to the reinforcing fibers during fiber spreading is preferably 0.02 to 0.1 g / fiber, more preferably 0.04 to 0.06 g / fiber. By applying a tension in such a range, the fiber spreadability is easily improved and fluffing due to single-fiber breakage is easily suppressed. If the tension is lower than 0.02 g / fiber, the fiber bundle is not sufficiently spread, and the average content in the thickness direction of the obtained spread reinforcing fibers may be too high. If the tension is higher than 0.1 g / fiber, fluffing due to single-fiber breakage may easily occur. In order to improve the fiber spreadability of the reinforcing fibers, at least one of ultrasonic fiber spreading, electrostatic fiber spreading, press fiber spreading, jet fiber spreading, and ventilation fiber spreading may be used.

[0075] A restraining agent may be attached to the opened reinforcing fibers. By attaching the restraining agent, it is easy to increase the restraint of the width of the opened reinforcing fibers, and it is also possible to suppress cracks that may occur when manufacturing a unidirectional prepreg. The restraining agent may be contained in the above-mentioned opening tank, or a tank (resizing tank) for attaching the restraining agent may be provided separately from the opening tank (desize tank) for removing the sizing agent contained in the reinforcing fibers. By attaching the restraining agent, it is easy to suppress the shrinkage of the opened reinforcing fibers in the width direction in the subsequent step (b). The amount of the restraining agent attached is preferably 0.8 mass% or less based on the mass of the reinforcing fibers, taking into consideration the effect on the deterioration of the physical properties of the finally obtained prepreg, and more preferably 0.3 to 0.5 mass%. Examples of the restraining agent are not particularly limited, but emulsified epoxy resins, modified polyolefin resins, and the like are preferably used.

[0076] The reinforcing fibers thus opened may then be subjected to a step of removing moisture and the like contained in the reinforcing fibers, a step of drying, and a step of winding, as necessary.

[0077] In the step of drying the opened reinforcing fibers, for example, a plurality of temperature-adjustable drying rolls may be used. The fiber bundle can be completely dried by sending it out so as to come into contact with the drying roll. The temperature of the drying roll may be appropriately changed depending on the tape width, the winding speed, the volatility of the solution in the opening tank, etc., but a temperature range of 80 to 200°C is preferably used. In addition, the temperature of each drying roll may be the same or different.

[0078] In addition, step (b) may be carried out directly after step (a), but when the production speed of each step is different due to the equipment, a step of winding up the opened reinforcing fibers may be included. In the winding step, a mechanism (winding shaft, motor, etc.) for winding the spread reinforcing fibers and a reel are used. The reel attached to the winding shaft rotates, so that the spread reinforcing fibers can be wound onto the reel. The winding speed may be changed appropriately depending on the spreadability of the fiber bundle, the width of the spread reinforcing fibers, etc., and is preferably 50 m / min or less, and more preferably 5 to 30 m / min. Winding at a speed within the above range is preferable because it is easy to increase the width precision.

[0079] In the process of winding the opened reinforcing fibers, in order to remove fuzz caused by breakage of the single yarns due to contact with each roller, for example, a scraper, brush, or the like may be provided so as to come into contact with the rollers.

[0080] From the viewpoint of easily improving the impregnation of the resin between the reinforcing fibers, it is preferable to open the fibers until the average number of fibers in the thickness direction is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, even more preferably 8 or less, even more preferably 7 or less, and particularly preferably 6 or less. Moreover, from the viewpoint of easily improving the permeation of the resin, the lower limit of the average number of fibers in the thickness direction is the better, and is not particularly limited, but may be, for example, 1 or more, in some cases 2 or more, and in other cases 3 or more.

[0081] The reinforcing fibers spread through the above process preferably have a coefficient of variation (CV) of width length of 20% or less, more preferably 10% or less, and further preferably 5% or less. The method of calculating such a coefficient of variation is as described above for the spread reinforcing fibers contained in the unidirectional prepreg. By setting the coefficient of variation of the width length to the above upper limit or less, when a random laminate is produced from the prepreg of the present disclosure, lamination unevenness is unlikely to occur, and the isotropy of the random sheet is easily ensured. According to the production method of the present disclosure, shrinkage in the width direction of the fibers after impregnation with the raw material compound is also easily suppressed, so that the coefficient of variation of the width length is easily reduced.

[0082] In step (b) following the step (a), the opened reinforcing fibers are treated with a compound represented by formula (1): TIFF0007672725000005.tif23168 [wherein n represents an integer of 1 to 4] and a bisphenol compound selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol E and bisphenol P.

[0083] The molecular weights of the bisphenol A type epoxy compound and the bisphenol compound used as raw materials to be impregnated in step (b) are each preferably not more than 2000. By using raw materials with low molecular weights and low viscosity in this way, the raw material compounds can easily penetrate between the reinforcing fibers opened during the production of the prepreg, and the obtained prepreg is in a state where the thermoplastic resin, which is a polymer of these compounds, is uniformly impregnated (fully impregnated) without containing voids between the fibers.

[0084] In step (b), from the viewpoint of strength, rigidity and heat resistance of the obtained molded body, the bisphenol A type epoxy compound and the bisphenol compound used as raw materials are impregnated at a mass ratio of preferably 50:50 to 90:10, more preferably 60:40 to 80:20. If the mass ratio of the bisphenol A type epoxy compound is equal to or higher than the above lower limit, it is preferable because it is easy to increase the heat resistance of the molded body obtained from the prepreg. Also, if the mass ratio of the bisphenol A type epoxy compound is equal to or lower than the above upper limit, it is preferable because it is easy to impregnate the opened reinforcing fibers with the bisphenol A type epoxy compound and the bisphenol compound in a well-dispersed state.

[0085] In step (b), any additive may be impregnated in addition to the above. Examples of additives include organic solvents, reaction accelerators, monofunctional epoxy compounds, coupling agents, curing agents, pigments, defoamers, fungicides, and deterioration inhibitors. When these additives are added, the amount may be appropriately changed depending on the purpose of addition. For example, a reaction accelerator may be used to promote the polymerization reaction of the resin. Bisphenol A type epoxy compounds and bisphenol compounds, which are raw materials for in situ polymerization type thermoplastic resins, are polymerized sequentially by electrophilic substitution reaction. Therefore, it is preferable to use basic phosphorus-based or amine-based reaction accelerators that easily promote electrophilic substitution reaction, and it is particularly preferable to use organic phosphorus compounds from the viewpoint of production speed.

[0086] As the organic phosphorus compound, triphenylphosphine, tri-para-tolylphosphine, diphenylcyclohexylphosphine, tricyclohexylphosphine, ethyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, 1,4-bisdiphenylphosphinobutanone, and the like are suitably used.

[0087] From the viewpoint of easily adjusting the weight-average molecular weight of the polymer of the above raw material compounds to a preferred range, it is preferable to use the reaction accelerator in an amount of 2 to 3 parts by mass per 100 parts by mass of the above polymer contained in the unidirectional prepreg. In addition, it is preferable to impregnate the reaction accelerator into the opened reinforcing fibers together with the mixture containing the raw material bisphenol A type epoxy compound, etc. in the step (b).

[0088] The monofunctional epoxy compound may be added from the viewpoint of suppressing excessive polymerization. The monofunctional epoxy compound is not particularly limited, but may be, for example, an aromatic monofunctional epoxy compound (particularly an alkylphenol monofunctional epoxy compound), an aliphatic hydrocarbon monofunctional epoxy compound, etc. In step (b), one type of monofunctional epoxy compound may be used, or two or more types of monofunctional epoxy compounds may be used in combination.

[0089] In step (b), the method of impregnating the bisphenol A type epoxy compound, which is the raw material of the in-situ polymerization type thermoplastic resin, with the bisphenol compound may be used to impregnate the opened reinforcing fiber as it is, or may be used to impregnate the reinforcing fiber with a varnish containing the raw material and an organic solvent. It is preferable to use a varnish to perform impregnation from the viewpoint of increasing the permeability of the reinforcing fiber by lowering the viscosity of the resin and impregnating the reinforcing fiber without generating voids between the reinforcing fibers. As the organic solvent that can be contained in the varnish, an organic solvent that is highly soluble in the bisphenol A type epoxy compound and the bisphenol compound is preferable, a polar solvent such as DNP·NMP is more preferable, a ketone solvent is even more preferable, and methyl ethyl ketone is particularly preferable. The content of the organic solvent is preferably 10 to 20 parts by mass with respect to 100 parts by mass of the raw material used from the viewpoint of impregnation of the raw material compound and productivity.

[0090] The impregnation method is not particularly limited, and may be performed by applying a compound or a solution thereof that is a raw material for the in-situ polymerization type thermoplastic resin to the upper and lower surfaces of the reinforcing fibers opened using a discharge die, or by immersing the opened reinforcing fibers in a solution containing a compound that is a raw material for the in-situ polymerization type thermoplastic resin. Here, the reinforcing fibers impregnated with the compound or the solution of the compound are likely to shrink in the width direction due to the surface tension of the compound or the solution. This shrinkage may cause an increase in thickness, disturbance in the direction of the fibers, the occurrence of cracks, etc. In order to prevent such shrinkage, it is preferable to use, for example, a coating device in step (b).

[0091] When the opened reinforcing fibers are immersed in a solution containing the raw material compound, the reinforcing fibers may be subjected to a squeezing process in which the raw material compound is impregnated and then the reinforcing fibers are squeezed with a roller to remove the liquid. The squeezing pressure P applied to the roller is preferably 0.05 MPa to 0.3 MPa, more preferably 0.1 MPa to 0.25 MPa. This allows void removal and control of the amount of impregnated compound. If the squeezing pressure is lower than the above lower limit, the amount of resin attached may not be stable and voids may remain inside the unidirectional prepreg. If the squeezing pressure exceeds the above upper limit, it may be difficult to increase the amount of resin in the unidirectional prepreg.

[0092] The resin impregnation amount in step (b) is preferably controlled so that the reinforcing fiber volume fraction Vf in the fiber reinforced thermoplastic resin sheet is preferably 10 to 80%, more preferably 15 to 60%, even more preferably 20 to 55%, even more preferably 25 to 45%, even more preferably 30 to 45%, even more preferably 35 to 45%, and particularly preferably 37.5 to 42.5%. The above range is preferable from the viewpoint of moldability of the fiber reinforced thermoplastic resin sheet. When the volume fraction is equal to or less than the above upper limit, it is easy to suppress the occurrence of intertwining points (unimpregnated parts) between fibers, and it is easy to reduce voids. When the volume fraction is equal to or more than the above lower limit, it is easy to increase the strength of the fiber reinforced thermoplastic resin sheet and the molded body.

[0093] Next, in step (c), the reinforcing fiber impregnated with the compound is heated to solidify the raw material compound impregnated in the reinforcing fiber. The solidification method is performed by heating. The heating temperature may be appropriately changed depending on the type of reinforcing fiber used, the type of solvent when a solution of the raw material compound is used, etc., but it is preferable to perform the heating in a temperature range higher than the glass transition temperature of the obtained thermoplastic resin and in which the reactive group of the raw material and the reaction accelerator are not deactivated, and it is preferable to heat in a temperature range of 100 to 200 ° C. The heating method is not particularly limited, but a heating method using near infrared rays, far infrared rays, or mid-infrared rays is preferably used. By this solidification, the bisphenol A type epoxy compound and the bisphenol compound are linearly polymerized to obtain a unidirectional prepreg containing an in situ polymerization type thermoplastic resin having a weight average molecular weight of, for example, 5,000 to 25,000, preferably 5,000 to 20,000, and more preferably 7,000 to 15,000. When impregnation is performed using a varnish containing a raw material and an organic solvent, a polymerization reaction between the bisphenol A type epoxy compound and the bisphenol compound proceeds as the solvent evaporates.

[0094] Next, in step (d), the unidirectional prepreg produced as described above is cut to a desired fiber length, and is arranged so as to be randomly laminated in a mold having a desired size, for example, to obtain a laminate. As a method of randomly laminating, when a fiber-reinforced thermoplastic resin sheet is continuously produced, a method of naturally dropping the unidirectional prepreg cut as described above from a high position and laminating it on a conveyor such as a steel belt, a method of blowing air into the falling path, or a method of attaching a baffle plate, etc. are preferably used. In addition, when producing by a batch method, a method of accumulating the unidirectional prepreg cut as described above in a container, attaching a conveying device to the bottom surface of the container, and distributing it to a mold for sheet production, etc. are preferably used.

[0095] In the process of randomly laminating unidirectional prepregs to obtain a laminate, the unidirectional prepregs are randomly laminated in a mold having a predetermined size (for example, 300 mm square or 600 mm square). In this case, the bulkiness of the obtained laminate varies depending on the length of the fiber direction of the unidirectional prepregs used, but is preferably about 20 to 50 mm and approximately uniform with respect to the mold surface. As a result, the number of unidirectional prepregs laminated in the thickness direction of the obtained fiber-reinforced thermoplastic resin sheet becomes constant, and the mechanical strength becomes isotropic.

[0096] Next, in step (e), the laminate may be heated at a temperature of preferably 100 to 200 ° C to obtain a fiber reinforced thermoplastic resin sheet. By heating, the thermoplastic resin is integrated, and the fiber reinforced thermoplastic resin sheet of the present disclosure is obtained. Pressurization may be performed together with heating. The heating temperature when producing the fiber reinforced thermoplastic resin sheet of the present disclosure is preferably 100 to 200 ° C, more preferably 150 to 180 ° C. When pressurization is performed, the pressure during pressurization is preferably 0.1 to 10 MPa, more preferably 1 to 5 MPa. Specifically, for example, a method in which a laminate of unidirectional prepregs laminated on a conveyer such as a steel belt is passed between hot rolls together with the steel belt, and heated, pressed, or intermittently pressed, a method in which heating and cooling are performed continuously by a belt press, a method in which preheating is performed by a far infrared heater and then cold pressing, or a batch method using a heating and cooling press, etc. may be mentioned. The heating temperature when producing the fiber-reinforced thermoplastic resin sheet of the present disclosure is preferably higher than the glass transition temperature of the in-situ polymerization type thermoplastic resin, and is preferably performed in a temperature range in which the reactive group of the raw material and the reaction accelerator are not deactivated, and is preferably heated in a temperature range of 100 to 200 ° C., more preferably 150 to 180 ° C. This makes it possible to maintain the fluidity of the resin while proceeding with the polymerization of the resin, and to fill the gaps between the laminated prepregs by further applying pressure. As a result, it becomes easier to reduce voids in the obtained molded body.

[0097] The sheet may be an aggregate (preform) in a state where the obtained laminate is temporarily fixed. For example, the obtained laminate is softened by heating (for example, at a temperature of 100 to 200°C), and is passed through upper and lower pressure rollers set to a predetermined gap (for example, 5 to 10 mm) to apply pressure to the prepregs contained in the laminate, thereby obtaining a preform.

[0098] When the fiber reinforced thermoplastic resin sheet of the present disclosure is manufactured by the manufacturing method including the above steps (a) to (e), since a unidirectional prepreg containing an in-situ polymerization type thermoplastic resin having a relatively low weight average molecular weight of 5,000 to 25,000 is used in step (b), further polymerization of the in-situ polymerization type thermoplastic resin proceeds in step (e) of heating the laminate. This polymerization is carried out not only within one unidirectional prepreg contained in the fiber reinforced thermoplastic resin sheet, but also between adjacent unidirectional prepregs. As a result, the unidirectional prepregs in the fiber reinforced thermoplastic resin sheet are bonded more firmly to each other, achieving high strength. In the step of heating the laminate, it is preferable to polymerize until the weight average molecular weight of the resulting polymer is 26,000 or more.

[0099] [Glass fiber reinforced thermoplastic resin] In the following, a glass fiber reinforced thermoplastic resin will be described as an example of a fiber reinforced plastic.

[0100] A glass fiber reinforced thermoplastic resin is a composite material that contains a thermoplastic resin as a matrix resin component and glass fibers as a fiber component.

[0101] The matrix resin component in the glass fiber reinforced thermoplastic resin may be any of the resin components described in [Resin Component], but preferably contains a polyolefin. Examples of polyolefins include homopolymers and copolymers having repeating units derived from one or more α-olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, and 1-dodecene, and are preferably polyethylene or polypropylene, and more preferably polypropylene.

[0102] As the glass fiber in the glass fiber reinforced thermoplastic resin, the glass fiber described in [Fiber component] can be used. In particular, the glass fiber may be a long fiber (for example, 5 mm or more, 30 mm or more, or 50 mm or more).

[0103] The glass fiber reinforced thermoplastic resin is preferably a glass mat reinforced thermoplastic resin. The glass mat reinforced thermoplastic resin is a sheet-like material in which a thermoplastic resin is impregnated into a glass mat in which glass fibers are accumulated in a random (non-woven) or woven form. In the glass mat, the glass fibers are preferably arranged isotropically.

[0104] Glass mat reinforced thermoplastic resins are commercially available, for example the GMT series from Mitsubishi Chemical Advanced Materials.

[0105] The fiber volume fraction Vf in the glass fiber reinforced thermoplastic resin (for example, glass mat reinforced thermoplastic resin) is preferably controlled to 10 to 80%, more preferably 15 to 60%, even more preferably 20 to 55%, even more preferably 25 to 45%, even more preferably 30 to 45%, even more preferably 35 to 45%, and particularly preferably 37.5 to 42.5%. The above-mentioned ranges are preferable from the viewpoint of moldability of the glass fiber reinforced thermoplastic resin and strength of the molded product.

[0106] A glass fiber reinforced thermoplastic resin (particularly a glass mat reinforced thermoplastic resin) may be used instead of a unidirectional prepreg, and a sheet may be produced in the same manner as the manufacturing method of the fiber reinforced thermoplastic resin sheet, which is a random laminate, described above, and the sheet may be subjected to a molding process for manufacturing a honeycomb plate. That is, the explanations of (d) and (e) in (Method for manufacturing a fiber reinforced thermoplastic resin sheet) can be applied to the case where a glass fiber reinforced thermoplastic resin (particularly a glass mat reinforced thermoplastic resin) is used instead of a unidirectional prepreg. Instead of the fiber reinforced thermoplastic resin sheet, which is a random laminate, a glass fiber reinforced thermoplastic resin in a sheet form (a glass fiber reinforced thermoplastic resin sheet) can be used as a raw material for a honeycomb plate. As an example of a glass fiber reinforced thermoplastic resin sheet, for example, a glass mat reinforced thermoplastic (GMT) manufactured by Mitsubishi Chemical Advanced Materials Corporation can be used.

[0107] [Manufacturing method of honeycomb board] The manufacturing method of the honeycomb plate in the present disclosure can employ various fiber-reinforced plastic molding methods, such as press molding. Press molding is a method of manufacturing a molded body by applying deformation such as bending, shearing, and compression to a fiber-reinforced plastic (for example, a fiber-reinforced thermoplastic resin sheet, particularly the above-mentioned fiber-reinforced thermoplastic resin sheet, which is a random laminate, or a glass fiber-reinforced thermoplastic resin sheet) cut to a predetermined size as necessary using a processing device and a mold. Examples of the molding form include deep drawing, flange, call gate, edge curling, and stamping. As a press molding method, a heat & cool method in which a mold is heated and molded and then cooled, and a cold press (stamping) method in which a sheet is heated and softened and molded in a low-temperature mold can be suitably used.

[0108] The conditions for producing the honeycomb board can be appropriately adjusted in view of the fluidity of the raw resin used. The pressing temperature can be, for example, 100 to 300°C, 150 to 250°C, or 180 to 220°C. The pressing pressure can be, for example, 0.1 to 10 MPa, 1 to 8 MPa, or 2 to 7 MPa. The pressing time can be, for example, 10 seconds to 10 minutes, 20 seconds to 5 minutes, or 30 seconds to 3 minutes. These conditions can be appropriately changed depending on the desired thickness, shape, etc. of the molded product.

[0109] The sole plate of the present disclosure may include a pair of rubber plates, the pair of honeycomb plates being disposed between the pair of rubber plates such that the pair of rubber plates sandwich the pair of honeycomb plates.

[0110] The rubber plate may be a member constituting the outermost surface of the floor plate. The rubber plate may have a plurality of grooves on its surface (particularly the surface constituting the outermost surface of the floor plate). The shape of the plurality of grooves is not limited, but is typically striped or mesh-like. A schematic diagram of a floor plate having a plurality of mesh-like grooves is shown in FIG. 2. The groove spacing between the grooves may be 3 mm or more, 5 mm or more, 8 mm or more, or 10 mm or more. The groove spacing between the grooves may be 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, or 10 mm or less. The groove width is not limited, but may be, for example, 0.1 mm or more, 0.3 mm or more, 0.5 mm or more, or 0.7 mm or more, and may be 5 mm or less, 3 mm or less, or 1 mm or less. By having a plurality of grooves on the surface of the rubber plate, the gripping force can be increased and the floor plate can be prevented from slipping or shifting when used. When the surface of another member (for example the non-honeycomb surface of a honeycomb plate) rather than the rubber plate is the outermost surface of the base plate, that surface may have a plurality of grooves as described above.

[0111] The thickness of the rubber plate may be 0.5 mm or more, 1 mm or more, 3 mm or more, or 5 mm or more. The thickness of the rubber plate may be 30 mm or less, 25 mm or less, 20 mm or less, 15 mm or less, 10 mm or less, 5 mm or less, or 3 mm or less. From the viewpoint of increasing the compressive strength, the thickness is preferably equal to or more than the lower limit, and from the viewpoint of weight reduction, the thickness is preferably equal to or less than the upper limit.

[0112] Examples of materials for the rubber plate include synthetic rubbers such as butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, fluororubber, silicone rubber, urethane rubber, ethylene propylene rubber, and epichlorohydrin rubber, and natural rubber.

[0113] <Middle plate> The floor plate of the present disclosure may include a mid-plate. The mid-plate is disposed between a pair of honeycomb plates so as to sandwich the honeycomb plate between the pair of mid-plates. By including the mid-plate, the load can be distributed and local load transfer caused by contact of the ribs can be suppressed, thereby improving the durability and compressive strength of the floor plate. Cross-sectional views of the floor plate when the mid-plate is not included and when the mid-plate is included are shown in Fig. 5 and Fig. 6, respectively. Note that the floor plates according to Figs. 5 to 7 do not need to include a rubber plate.

[0114] The thickness of the midplate may be 0.5 mm or more, 1 mm or more, 3 mm or more, or 5 mm or more. The thickness of the midplate may be 30 mm or less, 25 mm or less, 20 mm or less, 15 mm or less, 10 mm or less, 5 mm or less, or 3 mm or less. From the viewpoint of increasing the compressive strength, the thickness is preferably equal to or more than the lower limit, and from the viewpoint of weight reduction, the thickness is preferably equal to or less than the upper limit.

[0115] <Case> The sole plate of the present disclosure may include a housing. The housing is arranged to cover the side surface of the honeycomb plate. When a rubber plate and / or a middle plate are present, the housing may be arranged to cover the side surface of the rubber plate and / or the side surface of the middle plate.

[0116] The thickness of the midplate may be 0.5 mm or more, 1 mm or more, 3 mm or more, or 5 mm or more. The thickness of the midplate may be 30 mm or less, 25 mm or less, 20 mm or less, 15 mm or less, 10 mm or less, 5 mm or less, or 3 mm or less. From the viewpoint of increasing the compressive strength, the thickness is preferably equal to or more than the lower limit, and from the viewpoint of weight reduction, the thickness is preferably equal to or less than the upper limit.

[0117] The material for the middle plate is not particularly limited, and various materials having a certain degree of composition such as resin, metal, ceramic, etc. may be used, but from the standpoint of weight reduction and compressive strength, aluminum, carbon, fiber reinforced plastic (e.g., materials similar to honeycomb plates), etc. can be used.

[0118] <Handle> The bottom plate of the present disclosure may include a handle. The handle may be coupled to the mid-plate or the housing. A schematic diagram of the handle coupled to the housing is shown in Figure 2. When the handle is coupled to the mid-plate, a portion of the mid-plate may function as a handle by extending the mid-plate (see Figure 7).

[0119] <Use of the floor board> The floor plate in the present disclosure is lightweight and has excellent compressive strength, and is therefore used as a substitute for conventional floor plates in various fields. The floor plate in the present disclosure can be suitably used as an outrigger floor plate. The floor plate in the present disclosure can be suitably used as an outrigger floor plate. For example, the floor plate is suitably used as a floor plate for aerial work vehicles in construction related to social infrastructure facilities (e.g., road ancillary facility construction, communication cable construction, etc.).

[0120] Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. EXAMPLES

[0121] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0122] Example 1 A compression test was conducted (compressed from 0 to 7t at 10mm / min) using a pair of honeycomb plates, a pair of rubber plates, and a floor plate including a middle plate, and the load-displacement curve obtained is shown in Figure 8. As is clear from the load-displacement curve in Figure 8, the displacement was 0.8mm at a load of 70kN, indicating that the compression strength is comparable to that of wooden floor plates. The details of the floor plates used are as follows: Honeycomb plate height: approx. 10 mm (substrate thickness: 4 mm) Honeycomb plate material: Molded from a fiber-reinforced thermoplastic resin sheet manufactured in the same manner as in Example 10 of the literature (Patent No. 6176691), except that the length of the unidirectional prepreg in the fiber direction was 25 mm. Honeycomb shape: hexagonal honeycomb structure (maximum inner diameter of cell: approx. 20 mm) Rib shape (tapered (removal angle approx. 10°), rib tip R surface processed (R approx. 1.5 mm), rib bottom thickness approx. 6 mm) Rubber plate thickness: approx. 4 mm

[0123] Example 2 A compression test (compressed from 0 to 7t at 10mm / min) was conducted using a pair of honeycomb plates and a floor plate including a middle plate. Although the load-displacement curve is not shown, the displacement was 0.6mm at a load of 70kN, indicating that the compression strength is comparable to that of wooden floor plates. The details of the floor plates used are as follows. Honeycomb plate height: Approximately 10 mm (substrate thickness 4 mm, mesh-like grooves on the surface spaced 6 mm apart) Honeycomb plate material: Molded from a fiber-reinforced thermoplastic resin sheet manufactured in the same manner as in Example 10 of the literature (Patent No. 6176691), except that the length of the unidirectional prepreg in the fiber direction was 25 mm. Honeycomb shape: hexagonal honeycomb structure (maximum inner diameter of cell: approx. 40 mm) Rib shape (tapered (removal angle approx. 10°), rib tip R surface processed (R approx. 1.5 mm), rib bottom thickness approx. 6 mm)

[0124] Example 3 A compression test was conducted using a pair of honeycomb panels and a floor plate including a middle plate. A compression test (compression and unloading were repeated from 0 to 7t at 10mm / min) was conducted, and the load-displacement curve obtained after 2400 cycles, estimating one year of use, is shown in Figure 9. As is clear from the load-displacement curve in Figure 9, even after 2400 cycles of compression testing, the displacement was 0.8mm at a load of 70kN, indicating that the compression strength is comparable to that of wooden floor plates. The details of the floor plates used are as follows. Honeycomb plate height: Approximately 10 mm (substrate thickness 4 mm, mesh-like grooves on the surface spaced 6 mm apart) Honeycomb plate material: Glass mat reinforced thermoplastic resin (manufactured by Mitsubishi Chemical Advanced Materials) Honeycomb shape: hexagonal honeycomb structure (maximum inner diameter of cell: approx. 37 mm) Rib shape (tapered (draft angle approx. 14°), R surface processing on the tip and base of the rib (tip R approx. 1.5 mm, base R approx. 3 mm), thickness of the rib base approx. 9 mm) [Brief description of the drawings]

[0125] [Figure 1] 1 is a schematic diagram of an outrigger floor plate according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective view of one embodiment of a sole plate according to the present disclosure. [Diagram 3] FIG. 1 is a perspective view of a honeycomb board according to one embodiment of the present disclosure. [Figure 4] 4 is a perspective cross-sectional view of the honeycomb plate of FIG. 3 in the zx or zy plane. [Figure 4-2] FIG. 2 is a cross-sectional view (enlarged view of a rib portion) of a honeycomb plate having rib tips and bases chamfered with R according to one embodiment of the present disclosure. [Diagram 5] 1 is a cross-sectional view of a sole plate according to one embodiment of the present disclosure taken along the zx or zy plane. [Figure 6] 1 is a cross-sectional view of a sole plate according to one embodiment of the present disclosure taken along the zx or zy plane. [Figure 7] 1 is a cross-sectional view of an end of a sole plate according to one embodiment of the present disclosure taken along the zx or zy plane. [Figure 8] 1 is a load-displacement curve obtained by performing a compression test on a floor plate according to one embodiment of the present disclosure. [Figure 9] 1 is a load-displacement curve obtained by performing a compression test on a floor plate according to one embodiment of the present disclosure. [Explanation of symbols]

[0126] 1 bottom plate 2. Honeycomb board 3 Rubber Sheet 4. Middle Plate 5. Cabinet 6. Toride 7 Screw fastening 10. Aerial work platform 11 Outrigger

Claims

1. A bottom plate including a pair of honeycomb plates and a middle plate, The honeycomb plate is an integrally molded body having a substrate portion and ribs forming a honeycomb structure on one main surface of the substrate portion; The honeycomb plate is made of fiber-reinforced plastic, The pair of honeycomb plates are arranged such that the honeycomb surfaces having the ribs of each honeycomb plate face each other, The midplate is disposed between the pair of honeycomb plates.

2. 2. The sole plate of claim 1, wherein said honeycomb structure is a hexagonal honeycomb structure.

3. 2. The floor plate according to claim 1, wherein the ratio of the ribs to the vertical projected area of ​​the honeycomb surface is 20% or more and 60% or less.

4. 2. The floor plate according to claim 1, wherein the thickness of the rib is 3% to 30% of the maximum inner diameter of each cell of the honeycomb structure.

5. 2. The sole plate according to claim 1, wherein the volume occupied by the ribs is 10% to 60% of the hollow volume of each of the cells of the honeycomb structure.

6. The ratio of the ribs to the vertical projected area of ​​the honeycomb surface is 20% or more and 60% or less, The thickness of the rib is 3% or more and 40% or less of the maximum inner diameter of each cell of the honeycomb structure, 2. The sole plate according to claim 1, wherein the volume occupied by the ribs is 10% to 60% of the hollow volume of each of the cells of the honeycomb structure.

7. 2. The floor plate of claim 1, wherein the ribs are tapered with a draft angle of 0.5° to 30°.

8. The floor plate according to claim 1 , wherein the tips of the ribs are rounded.

9. The floor plate according to claim 1 , wherein the base of the rib is chamfered.

10. 2. The floor plate according to claim 1, wherein the honeycomb plate has a thickness of 50 mm or less, and the height of the ribs is 30% to 90% of the thickness of the honeycomb plate.

11. The sole plate of claim 1 , wherein the outermost surface of the sole plate has a plurality of grooves.

12. 2. The floor plate of claim 1, wherein the fiber reinforced plastic is a glass fiber reinforced thermoplastic.

13. 13. The floor plate of claim 12, wherein the glass fiber reinforced thermoplastic resin is a glass mat reinforced thermoplastic resin.

14. 2. The floor plate of claim 1, wherein the fiber reinforced plastic is a carbon fiber reinforced thermoplastic.

15. 2. The flooring plate according to claim 1, wherein the honeycomb plate is a molded product of a random laminate of unidirectional prepregs.

16. The sole plate of claim 1 , further comprising a housing, the housing being disposed to surround a side surface of the honeycomb plate.

17. 20. The sole plate of claim 1 or 16, including a handle, said handle coupled to said mid-plate or said housing.

18. 2. The deck of claim 1 which is an outrigger deck.

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