JP6363834B2 - Hollow structure and method for producing the same - Google Patents

Description

The present invention relates to a synthetic resin hollow structure and a method for producing the same .

  As a member for assembling products such as distribution containers, shelves, bulletin boards, and partitions for logistics, a hollow structure molded using a synthetic resin is used.

  Patent Document 1 describes a conventional hollow structure made of synthetic resin. As shown in FIG. 10, this hollow structure is formed of a synthetic resin core material 102 having an uneven shape and a pair of thermoplastic synthetic resin sheets 104 and 106. The core material 102 has a plurality of cylindrical recesses 110 formed on one surface side by recessing a large number of portions on one surface side of the thermoplastic synthetic resin sheet into a cylindrical shape, and a large number of circles on the other surface side. A columnar convex portion 112 is formed. The synthetic resin sheets 104 and 106 are heated and welded to the one surface side and the other surface side of the core material 102, respectively, thereby forming a hollow structure.

JP-A-10-156985

  In the above-described conventional hollow structure, when the synthetic resin sheet 104 is heat-welded to one surface side of the core material 102, the space in the recess 110 is closed by the synthetic resin sheet 104 to become a sealed space. Therefore, when the temperature decreases after the synthetic resin sheet 104 is heated and welded, the volume of air is reduced in the sealed space in the recess 110, and a large number of depressions are generated in the synthetic resin sheet 104.

  In the hollow structure, if a large number of depressions are generated in the surface of the synthetic resin sheet 104, the design property is deteriorated, and the surface of the hollow structure after molding (that is, the surface of the synthetic resin sheet 104 in which a large number of depressions are generated). ) Is difficult to print.

  The present invention was invented in view of the above problems, and in a hollow structure formed by covering both surfaces of a synthetic resin core material having an uneven shape with a synthetic resin sheet, the sheet adhered to the core material It is a problem to prevent the dents.

  In order to solve the above problems, the hollow structure of the present invention has the following configuration.

The present invention covers a synthetic resin-made core material having an uneven shape in the thickness direction, a synthetic resin-made first sheet covering one of the core materials in the thickness direction, and the other of the core material in the thickness direction. A second sheet made of synthetic resin, wherein the material of the core material, the material of the first sheet, and the material of the second sheet are the same, and the core material is A first convex portion having a first surface facing one side and a second surface facing the other side in the thickness direction and projecting in a triangular frustum shape on the first surface is a staggered pattern in a plan view. A large number of first concave portions that are recessed in a triangular frustum shape are arranged in a staggered manner, and a second convex portion that protrudes in a triangular frustum shape is staggered in plan view on the second surface And a plurality of second concave portions recessed in a triangular frustum shape are arranged in a staggered manner, and the first convex portion and the front The second recesses are positioned one-on-one on the front and back sides, the second projections and the first recesses are positioned one-on-one on the front and back sides, and the first surface has a number of reference points that are regularly arranged. The three first convex portions and the three first concave portions are alternately arranged so as to surround each of the plurality of reference points, and the second surface surrounds each of a plurality of regularly arranged reference points, The second convex portions and the three second concave portions are alternately arranged, and a plurality of reference points on the first surface and a plurality of reference points on the second surface are intermediate portions in the thickness direction of the core material. The radius of curvature of the ridge line of the first convex portion and the radius of curvature of the valley line of the first concave portion, which are located one-to-one on the front and back sides, are set so that the latter curvature radius is smaller than the curvature radius of the former. It is the hollow structure characterized by having.

In addition, the present invention provides a vacuum molding on a synthetic resin core sheet using a mold in which a plurality of concave portions for vacuuming recessed in a triangular frustum shape and a plurality of convex portions protruding in a triangular frustum shape are arranged in a staggered manner. By applying a synthetic resin core material having a concavo-convex shape in the thickness direction, and attaching a synthetic resin first sheet to one side of the core material in the thickness direction; Adhering a second sheet made of the same material as the first sheet to the other side of the core material in the thickness direction, and the recess has a triangular bottom surface, and each of the bottom surfaces A suction hole for evacuation is provided in the vicinity of the apex, and the radius of curvature of the valley line that the concave portion has and the radius of curvature of the ridge line that the convex portion has are the latter than the radius of curvature of the former. and the curvature radius is smaller, the co formed with the mold The material has a first surface that faces one side in the thickness direction and a second surface that faces the other side in the thickness direction, and the first protrusion protrudes in a triangular frustum shape on the first surface. A plurality of portions are arranged in a staggered manner in a plan view, and a plurality of first concave portions that are recessed in a triangular frustum shape are arranged in a staggered manner, and a second convex portion that protrudes in a triangular frustum shape on the second surface However, a large number of zigzag-shaped second concave portions are arranged in a staggered pattern in plan view, and a large number of zigzag-shaped second concave portions are arranged, and the first convex portion and the second concave portion are positioned one-on-one on the front and back sides The second convex portion and the first concave portion are positioned one-to-one on the front and back sides, and the first surface includes three first convex portions surrounding each of a plurality of regularly arranged reference points. And the first concave portions are alternately arranged, and the second surface surrounds each of a number of regularly arranged reference points. The three second convex portions and the three second concave portions are alternately arranged, and a plurality of reference points on the first surface and a plurality of reference points on the second surface are intermediate in the thickness direction of the core material. It is a manufacturing method of the hollow structure characterized by being located in the front and back one-on-one by a part.

  According to the present invention, in a hollow structure formed by covering both surfaces of a synthetic resin core material having a concavo-convex shape with a synthetic resin sheet, it is possible to suppress the formation of a depression in the sheet adhered to the core material. Therefore, the surface of the hollow structure after molding becomes flat and the design is improved. In addition, there is an effect that the surface can be printed easily and cleanly. In addition, since the design and physical front and back of the hollow structure after molding are unlikely to occur, there is an effect that a product can be manufactured without worrying about the front and back of the hollow structure.

It is a perspective view of the hollow structure of a 1st embodiment of the present invention. It is a perspective view of the core material with which the hollow structure same as the above is provided. It is a front view of a core material same as the above. It is a rear view of a core material same as the above. It is a side view of a core material same as the above. It is a principal part perspective view of the type | mold for shape | molding a core material same as the above. It is a principal part front view which shows the basic dimension shape of a core material same as the above. It is the sectional view on the AA line of FIG. It is a front view of the core material with which the hollow structure of 2nd Embodiment of this invention is provided. It is a fracture | rupture perspective view which shows the principal part of the conventional hollow structure.

  A hollow structure according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view of the hollow structure of the present embodiment. The hollow structure is formed by attaching a synthetic resin first sheet 8 to the first surface 4 of the synthetic resin core material 2 shown in FIGS. This is a panel-like hollow structure to which a second sheet 10 made of synthetic resin is attached.

  As materials for the core material 2, the first sheet 8, and the second sheet 10, polypropylene, polyethylene, polycarbonate, polylactic acid, and the like are used, respectively. The core material 2, the first sheet 8, and the second sheet 10 may be made of different materials, but are preferably the same material so as not to be easily peeled off. Each may be a single layer, or may be a stack of a plurality of equivalent materials. In the case of stacking equivalent materials, for example, it is possible to stack block polypropylene and homopolypropylene.

  The core material 2 has a first surface 4 and a second surface 6 on opposite sides of the thickness direction 12 so as to face opposite directions. 2 is a perspective view of the core material 2, FIG. 3 is a front view seen from the first surface 4 side, FIG. 4 is a rear view seen from the second surface 6 side, and FIG. 5 is a side view.

  The core material 2 is formed by processing irregularities on the sheet material along a mold 16 as shown in FIG. 6 using a thermoplastic synthetic resin sheet material. Specifically, using a vacuum forming roll having the mold 16 on the surface, the surface of the sheet material softened by heating is sequentially sucked into the mold 16 while rotating the vacuum forming roll, and the sheet material is uneven. Will be formed.

  The mold 16 has a concavo-convex shape in which a large number of concave portions 18 are regularly arranged so as to be staggered. The concave portion 18 has a shape that is recessed in a triangular frustum shape, and the bottom surface of each concave portion 18 has an equilateral triangular shape of the same size. A suction hole 20 for evacuation is formed in the center of the bottom surface of each recess 18. That is, each recess 18 included in the mold 16 serves as a suction cavity for evacuation. The location where the suction hole 20 for evacuation is formed may be a location in the vicinity of each vertex of the triangular bottom surface of each recess 18.

  Here, the zigzag pattern means a state in which adjacent objects are arranged so as to be different from each other when viewed along a predetermined reference direction. Speaking of the mold 16, for example, when a perpendicular line is drawn from one vertex of the bottom surface of the recess 18 to the opposite side and a direction parallel to the perpendicular is taken as a reference direction, the many recesses 18 included in the mold 16 have the reference They are arranged alternately along the direction (that is, in a staggered manner).

  In the mold 16, a large number of convex portions 22 protruding in a triangular frustum shape are formed between adjacent concave portions 18 having a triangular frustum shape. These many convex parts 22 are regularly arrange | positioned so that it may become zigzag form. The top surface of each convex portion 22 has a regular triangular shape of the same size.

  As shown in FIGS. 2, 5, and the like, the core material 2 processed with unevenness by vacuum forming using the mold 16 having the above-described configuration includes a resin member having uneven shapes on the first surface 4 and the second surface 6. Become.

  As shown in FIG. 3, the first surface 4 includes a plurality of triangular frustum-shaped first convex portions 24 arranged in a staggered manner, and a triangular frustum-shaped first concave portion 26 arranged in a staggered manner. Are molded along the concavo-convex shape of the mold 16. The 1st convex part 24 is formed along each recessed part 18 which the type | mold 16 has, and has a regular triangular top surface. The 1st recessed part 26 is formed along each convex part 22 which the type | mold 16 has, and has an equilateral triangular bottom face.

  In the first surface 4, three first convex portions 24 are arranged at locations that surround the predetermined reference point 28 and are equally spaced in the circumferential direction. The reference point 28 is located at an intermediate portion in the thickness direction 12 of the core material 2. The first surface 4 has such a large number of reference points 28 in a regular arrangement, and has a large number of first convex portions 24 surrounding the reference points 28 continuously.

  The first convex portion 24 has a ridge line 30, and the ridge lines 30 of the three first convex portions 24 intersect at a reference point 28. Similarly, three first concave portions 26 are arranged at locations that surround the reference point 28 and are equally spaced in the circumferential direction. The first recess 26 has a valley line 32, and the valley lines 32 of the three first recesses 26 intersect at this reference point 28. Both the ridge line 30 and the valley line 32 have a slight width. On the first surface 4, irregularities are symmetrically formed with reference to an intermediate portion in the thickness direction 12 of the core material 2. In addition, the circumferential interval between the first convex portions 24 arranged on the first surface 4 and the circumferential interval between the first concave portions 26 may be set to slightly different intervals instead of equal intervals. Further, the position of the reference point 28 may not be a strict intermediate point in the thickness direction 12, and the reference point 28 may be located at a position slightly shifted from the strict intermediate point in the thickness direction 12. In this case, the unevenness of the core material 2 is not strictly symmetric, but has a substantially symmetric shape.

  As shown in FIG. 4, the second surface 6, which is in a front-and-back relationship with the first surface 4, is arranged in a large number of triangular frustum-shaped second convex portions 34 that are arranged in a staggered manner, and a plurality of staggered shapes. A triangular concave truncated conical second recess 36 is formed along the concave and convex shape of the mold 16. The 2nd convex part 34 is the back surface side of the 1st recessed part 26 which the 1st surface 4 has, and has an equilateral triangular top surface. The 2nd recessed part 36 is a back surface side of the 1st convex part 24 which the 1st surface 4 has, and has an equilateral triangular bottom face.

  On the second surface 6, three second convex portions 34 are arranged at locations that surround the predetermined reference point 38 and are equally spaced in the circumferential direction. The reference point 38 is located in the middle portion of the core material 2 in the thickness direction 12. The second surface 6 has such a large number of reference points 38 in a regular arrangement, and continuously has a large number of second convex portions 34 surrounding the reference points 38. The reference point 38 on the second surface 6 and the reference point 28 on the first surface 4 are in a front-back relationship.

  The second convex portion 34 has a ridge line 40, and the ridge lines 40 of the three second convex portions 34 intersect at a reference point 38. Similarly, three second recesses 36 are arranged at locations spaced around the reference point 38 at equal intervals in the circumferential direction. The second recess 36 has a valley line 42, and the valley lines 42 of the three second recesses 36 intersect at this reference point 38. Both the ridge line 40 and the valley line 42 have a slight width. Thus, also on the second surface 6, unevenness is symmetrically formed with reference to the intermediate portion of the core material 2 in the thickness direction 12. The circumferential interval between the second convex portions 34 and the circumferential interval between the second concave portions 36 may be set to slightly different intervals instead of equal intervals. Further, the position of the reference point 38 may be a position slightly deviated from a strict intermediate point in the thickness direction 12, and in this case, the unevenness has a substantially symmetrical shape.

  By the way, the vicinity of the reference point 38 is a place where wrinkles called bridges are likely to occur during vacuum forming. When a bridge is generated at this location, the other portion becomes thinner and the compressive strength is reduced. When the first sheet 8 or the second sheet 10 is adhered to the core material 2, the core material 2 is crushed. It becomes easy.

  The bridge at this point is more likely to occur as the inclination angle of the second concave portion 36 positioned surrounding the reference point 38 is closer to the vertical, and the ridge line 40 of the second convex portion 34 positioned surrounding the reference point 38. The smaller the radius of curvature, the more likely it is. Therefore, in order to prevent the occurrence of a bridge, the inclination of the side wall of the second concave portion 36 having a triangular frustum shape from the vertical is set to 20 ° or more, and the ridge line 40 of the second convex portion 34 is set to 0.5 mm or more. It is preferable to set to a convex curved surface having a curvature radius of. More preferably, the inclination of the side wall of the second concave portion 36 having a triangular frustum shape is set to 20 ° or more, and the curvature radius of the ridge line 40 of the second convex portion 34 is set to 1 mm or more.

  In addition, the 2nd convex part 34 of the 2nd surface 6 is formed along each convex part 22 which the type | mold 16 has, and the 2nd recessed part 36 of the 2nd surface 6 is formed along each concave part 18 which the type | mold 16 has. It is what is done. Therefore, in order to prevent the occurrence of bridging during vacuum forming, that is, the inclination of the side wall of each concave portion 18 having a triangular frustum shape is set to 20 ° or more, and the ridge line of each convex portion 22 having a triangular frustum shape is formed. It is preferable to set a convex curved surface having a radius of curvature of 0.5 mm or more (more preferably 1 mm or more).

  The sheet material using the latter curvature radius for the core material 2 in comparison with the curvature radius of the ridge line of each convex portion 22 of the mold 16 and the curvature radius of the ridge line of each convex section 22 of the mold 16. It is preferable to set it smaller by the thickness of According to this setting, it is possible to make the radii of curvature of the first convex portion 24 and the ridge line 40 of the second convex portion 34 of the core material 2 after molding coincide with each other.

  The first sheet 8 adhered to the first surface 4 of the structure is heat-welded to the top surface of each first convex portion 24 arranged in a staggered manner on the first surface 4. Similarly, the 2nd sheet | seat 10 stuck on the 2nd surface 6 of the said structure is heat-welded with respect to the top surface of each 2nd convex part 34 arrange | positioned on the 2nd surface 6 in zigzag form.

  At this time, the space formed between the first surface 4 of the core material 2 and the first sheet 8 is all communicated with each other through the space between the adjacent first convex portions 24 and also communicated with the external space. It becomes a state. That is, since there is no sealed space closed by the first sheet 8 on the first surface 4 side, it is possible to prevent a large number of depressions from being generated in the first sheet 8 after heat welding.

  Similarly, the space formed between the second surface 6 of the core material 2 and the second sheet 10 is all communicated with each other through the space between the adjacent second convex portions 34 and also communicated with the external space. It becomes a state. Even on the second surface 6 side, there is no sealed space closed by the second sheet 10, and it is possible to prevent a large number of depressions from being generated in the second sheet 10 after heat welding.

  In addition, since the core material 2 is formed substantially symmetrically with respect to the intermediate portion in the thickness direction 12, the hollow structure formed by sandwiching the core material 2 from both sides with the sheets 8 and 10 is isotropic. It becomes an excellent panel.

  7 and 8 show the basic dimensional relationship of the hollow structure of the present embodiment. FIG. 7 shows a basic arrangement of the first protrusions 24 on the first surface 4 side, and FIG. 8 shows a cross section taken along line AA in FIG.

  The basic shape of the first convex portion 24 having a triangular frustum shape is an equilateral triangular lower base 50, an equilateral triangular upper base 52 having a smaller area than the lower base 50, and each side of the lower base 50. It is represented by three convenient side surfaces 54 that connect the sides of the upper bottom surface 52 one-to-one. The lower bottom surface 50 is a virtual surface located in the middle of the thickness direction 12 of the core material 2, and each vertex of the lower bottom surface 50 serves as a reference point 28. The lower bottom surfaces 50 of the three adjacent first convex portions 24 are arranged such that their vertices overlap at the reference point 28.

  Each side surface 54 is inclined by an angle θ when the direction perpendicular to the lower bottom surface 50 and the upper bottom surface 52 (the thickness direction 12 of the core material 2) is used as a reference. Each vertex of the lower bottom surface 50 and each vertex of the upper bottom surface 52 are connected one-to-one via the ridge line 30.

  The arrangement of the first protrusions 24 on the first surface 4 is set with reference to a regular hexagonal cell 60. The cells 60 are arranged in a honeycomb shape on the first surface 4 side, and among the six vertices of each cell 60 that is a regular hexagon, three vertices that are skipped one by one are the reference points 28. It becomes.

  Since the irregularities on the front and back of the core material 2 are formed symmetrically with respect to the intermediate portion in the thickness direction 12, the arrangement and size of the second protrusions 34 on the second surface 6 side are the same on the first surface 4 side. This is the same as the arrangement and dimensions of the first protrusions 24.

  Here, the cell size which is a dimension between two parallel sides of the cell 60 is CS [mm], the entire thickness of the hollow structure is Tb [mm], and the thickness of the core material 2 formed in the unevenness is Tc [mm]. ], The thickness of the core sheet forming the core material 2 is Tcs [mm], and the thickness of the first sheet 8 and the second sheet 10 is Tss [mm].

In the present embodiment, the cell size CS = 9.0 [mm], the hollow structure thickness Tb = 5.6 [mm], the core material 2 thickness Tc = 4.8 [mm], and the core material 2 are formed. The core sheet has a thickness Tcs = 0.3 [mm], and the first sheet 8 and the second sheet 10 have a thickness Tss = 0.4 [mm]. Since the cell 60 is a regular hexagon, the area S0≈70.1 [mm ² ] of each cell 60 provided at the cell size CS = 9.0 [mm], and the area of the lower bottom surface 50 of the first convex portion 24 is obtained. S2 = S0 / 2≈35.1 [mm ² ], and the area of the upper bottom surface 52 is S1≈14.1 [mm ² ]. The inclination of the first convex portion 24 is provided at an angle θ = 25.0 [°].

At this time, the ratio of the area S1 [mm ² ] of the upper bottom surface 52 to the area S2 [mm ² ] of the lower bottom surface 50 of the first convex portion 24 is S1 / S2≈40 [%]. The upper bottom surface 52 of the first convex portion 24 is an adhesive surface to which the first sheet 8 is bonded by thermal welding. Therefore, the bonding area ratio on one side of the core material 2 is S1 / S0≈20 [%]. These dimensional relationships are also the same on the second surface 6 side where the second convex portions 34 are arranged in a staggered manner.

  That is, in the hollow structure of the present embodiment, the frustum-shaped first convex portions 24 arranged in a staggered manner on the front side of the core material 2 and the frustum-like shapes arranged in a staggered manner on the back side of the core material 2. Each of the second convex portions 34 has a basic shape in which the area ratio between the lower base and the upper base is about 40 [%], the adhesion area ratio is about 20 [%], and the inclination θ is 25.0 [°]. Furthermore, the thickness Tc of the core material 2 is 4.8 [mm], and the thickness Tcs of the core sheet forming the core material 2 is 0.3 [mm].

At this time, the bonding strength of the core material 2 to the first sheet 8 and the second sheet 10 is ensured with sufficient bonding strength because the bonding area ratio is about 20 [%]. Further, according to the hollow structure of the present embodiment made of polypropylene, the compression strength is 0.35 to 0.45 [Mpa], the bending strength is 17.2 to 23.7 [Nm / m] under the above conditions, The experimental result that bending rigidity is 4.8-6.6 [Nm < ² > / m] is obtained, and it can be used for various uses with a load. Moreover, the weight per unit area is 990 [g / mm ² ], which is a very light plate material of about 20% compared with a solid plate material made of the same material.

  Note that the actual hollow structure has a size that is slightly crushed in the thickness direction by the pressure when the first sheet 8 and the second sheet 10 are pasted. Therefore, in practice, the thickness Tb of the hollow structure is 4.3 to 4.9 [mm], and the thickness Tc of the core material 2 is 3.5 to 4.1 [mm].

  Here, it is preferable that the bonding area ratio of the core material 2 included in the hollow structure is in the range of 1 to 46 [%].

  No. in Table 1 below. 1 to 11, the adhesion area ratio calculated when the cell size CS is set to 9.0 [mm] and the inclination θ is varied within the range of 5.6 to 49.7 [°]. Show. No. in Table 1 12 to 27, the bonding area ratio calculated when the cell size CS is varied within the range of 3.3 to 500.0 [mm] with a constant inclination θ = 25.0 [°]. Show.

  No. in Table 1 below. 1 to 27, the hollow structure thickness Tb = 5.6 [mm], the core material 2 thickness Tc = 4.8 [mm], the core sheet thickness Tcs = 0.3 [mm], the first This is a case where the sheet 8 and the second sheet 10 are provided with a thickness Tss = 0.4 [mm]. The thicknesses Tb [mm] and Tc [mm] of the hollow structure and the core material 2 are actually smaller than this due to crushing during sheet sticking. D [mm] shown in Table 1 is a distance between the apex of the upper bottom surface 52 having a triangular shape and another adjacent cell 60.

  In Table 1 below, no. No. 6 and no. The case of 16 is the same. Also from the results of Table 1, the adhesion area ratio is in the range of 1 to 46 [%], that is, No. 2-10, no. It turns out that the case of 13-26 is preferable.

  Next, the hollow structure body of 2nd Embodiment of this invention is demonstrated based on FIG. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected, detailed description is abbreviate | omitted, and only the characteristic structure different from 1st Embodiment is explained in full detail below.

  In the hollow structure of the present embodiment, as shown in FIG. 9, the top surfaces of the first convex portions 24 adjacent to each other on the first surface 4 are arranged while being shifted in one direction. That is, in the first surface 4 of the first embodiment, the top surfaces of the adjacent first convex portions 24 are provided in such a relationship that one side of each equilateral triangle is positioned on a straight line (see FIG. 3), in this embodiment, the top surfaces of the adjacent first convex portions 24 are provided in such a relationship that one side of each equilateral triangle is parallel and not positioned on a straight line.

  The bottom surfaces of the first concave portions 26 adjacent to each other on the first surface 4 are also arranged while being shifted in one direction. In other words, in the present embodiment, the bottom surfaces of the adjacent first concave portions 26 are provided in such a relationship that one side of each equilateral triangle is parallel and not positioned on a straight line.

  Since the second surface 6 of the core material 2 is in a front-back relationship with the first surface 4, the second convex portion 34 and the second concave portion 36 formed on the second surface 6 are also the first convex on the first surface 4 side. It arrange | positions with the form similar to the part 24 and the 1st recessed part 26. FIG.

  As described above with reference to the accompanying drawings, the hollow structures of the first and second embodiments of the present invention include a core material 2 made of synthetic resin having an uneven shape and one of the core material 2 in the thickness direction 12. And the first and second sheets 8 and 10 made of synthetic resin that cover the other side, respectively. The core material 2 includes a plurality of frustum-shaped first convex portions 24 projecting on one side in the thickness direction 12 in a zigzag shape in plan view, and a frustum projecting on the other side in the thickness direction 12 A large number of the second convex portions 34 are arranged in a staggered manner in a plan view.

  According to the hollow structure of the said structure, since the sealed space does not arise when the 1st sheet 8 and the 2nd sheet | seat 10 are stuck on the core material 2, the 1st sheet 8 and the 2nd sheet | seat 10 are depressed after sticking. Is prevented.

  For this reason, the hollow structure having the above-described structure has high designability, and it is difficult for dust to accumulate on the surface. In addition, when the surface of the first sheet 8 or the second sheet 10 can be easily and cleanly printed, and other materials such as aluminum are pasted on the surface of the first sheet 8 or the second sheet 10 It is also easy to provide an adhesive strength that does not easily peel off. In addition, the hollow structure having the above-described structure has an advantage that a design front and back are less likely to occur, and an advantage that a front and back are less likely to occur in terms of physical properties, so a product can be manufactured without worrying about the front and back of the hollow structure. be able to. Therefore, the hollow structure of the first and second embodiments is a member that can be suitably used for various uses such as a transportation container for distribution, a shelf, a bulletin board, and a partition.

  In the hollow structures of the first and second embodiments of the present invention, the first convex portion 24 and the second convex portion 34 of the core material 2 are formed by vacuum forming a synthetic resin sheet using the mold 16. It is formed continuously. Therefore, it is possible to continuously form the core material 2 having a predetermined uneven shape by continuously feeding the sheet.

  The mold 16 may be a structure that performs thermoforming of a synthetic resin sheet, and may have a structure that performs, for example, vacuum / pressure forming, press forming, or the like. Specifically, for example, a vacuum forming roll having a mold 16 and a forming roll that is paired with the vacuum forming roll, a structure that assists the forming with the forming roll, a forming roll having a mold 16, A forming roll and another forming roll paired with the forming roll, a structure that assists forming with the other forming roll, a structure that performs forming with a vacuum formed flat plate having the mold 16, a vacuum formed flat plate having the mold 16, and A structure that includes a flat plate that forms a pair with the vacuum formed flat plate and assists the forming with the flat plate can be employed.

  As mentioned above, although this invention was demonstrated based on embodiment shown to an accompanying drawing, this invention is not limited to embodiment of each said example, If it is in the range which this invention intends, in each example suitably It is possible to change the design of the above and to apply a combination of the configurations of the examples as appropriate.

  For example, in each embodiment, although the shape of the 1st convex part 24 and the 2nd convex part 34 is provided in the triangular frustum, it is not restricted to this, Other polygonal frustum shapes, such as a square frustum and a hexagonal frustum, It is also possible to adopt a shape such as a truncated cone or the like, or it is possible to adopt a shape having a polygonal truncated cone shape and a curved side surface. Moreover, the shape of the 1st convex part 24 or the 2nd convex part 34 may be a polygonal frustum shape, and the side surface may be formed in step shape with a level | step difference, or it may be a truncated cone shape, The side surface may be formed in a stepped shape by a step.

  In each embodiment, the top surface of the first convex portion 24, the bottom surface of the first concave portion 26, the top surface of the second convex portion 34, and the bottom surface of the second concave portion 36 are all equilateral triangles of the same type. However, it can also be formed into slightly different dimensions. In other words, the top surface of the convex portion 22 and the bottom surface of the concave portion 18 of the mold 16 for molding the core material 2 are not limited to the equilateral triangle shape of the same type, and may be provided with slightly different dimensions.

  Further, in each embodiment, the suction hole 20 is formed on the bottom surface of each recess 18 so that the recess 18 serves as a suction cavity. However, the mold 16 is formed by combining a plurality of molds, It is also possible to adopt a structure for evacuating from the gap.

2 Core material 4 First surface 6 Second surface 8 First sheet 10 Second sheet 12 Thickness direction 16 Type 24 First convex portion 34 Second convex portion

Claims (2)

A core material made of synthetic resin having an uneven shape in the thickness direction;
A first sheet made of a synthetic resin covering one of the core material in the thickness direction;
A second sheet made of a synthetic resin covering the other of the core material in the thickness direction,
The material of the core material, the material of the first sheet, and the material of the second sheet are the same,
The core material is
A first surface facing one side of the thickness direction and a second surface facing the other side of the thickness direction;
On the first surface, a plurality of first convex portions protruding in a triangular frustum shape are arranged in a staggered manner in a plan view, and a plurality of first concave portions recessed in a triangular frustum shape are arranged in a staggered shape,
On the second surface, a plurality of second convex portions protruding in a triangular frustum shape are arranged in a staggered manner in a plan view, and a plurality of second concave portions recessed in a triangular frustum shape are arranged in a staggered shape,
The first convex portion and the second concave portion are located one-on-one on the front and back sides,
The second convex portion and the first concave portion are located one-on-one on the front and back sides,
In the first surface, the three first convex portions and the three first concave portions are alternately arranged so as to surround each of a plurality of regularly arranged reference points.
In the second surface, surrounding each of a large number of regularly arranged reference points, the three second convex portions and the three second concave portions are alternately arranged,
A large number of reference points on the first surface and a large number of reference points on the second surface are located on the front and back in a one-to-one manner in the middle part of the thickness direction of the core material ,
A hollow structure characterized in that the radius of curvature of the ridge line of the first convex portion and the radius of curvature of the valley line of the first concave portion are set such that the latter radius of curvature is set smaller than the former radius of curvature. body. By applying vacuum forming to the core sheet made of synthetic resin, using a mold in which a plurality of concave portions for vacuum suction recessed in a triangular frustum shape and a plurality of convex portions protruding in a triangular frustum shape are arranged in a staggered manner, Forming a core material made of synthetic resin having an uneven shape in the thickness direction;
Adhering a synthetic resin first sheet to one side of the core material in the thickness direction;
Adhering a second sheet of the same material as the first sheet to the other side of the core material in the thickness direction,
The concave portion has a triangular bottom surface, and is provided with a suction hole for evacuation at a location near each vertex of the bottom surface,
In the curvature radius of the valley line that the concave portion has and the curvature radius of the ridge line that the convex portion has, the curvature radius of the latter is set smaller than the curvature radius of the former,
The core material formed using the mold is
A first surface facing one side of the thickness direction and a second surface facing the other side of the thickness direction;
On the first surface, a plurality of first convex portions protruding in a triangular frustum shape are arranged in a staggered manner in a plan view, and a plurality of first concave portions recessed in a triangular frustum shape are arranged in a staggered shape,
On the second surface, a plurality of second convex portions protruding in a triangular frustum shape are arranged in a staggered manner in a plan view, and a plurality of second concave portions recessed in a triangular frustum shape are arranged in a staggered shape,
The first convex portion and the second concave portion are located one-on-one on the front and back sides,
The second convex portion and the first concave portion are located one-on-one on the front and back sides,
In the first surface, the three first convex portions and the three first concave portions are alternately arranged so as to surround each of a plurality of regularly arranged reference points.
In the second surface, surrounding each of a large number of regularly arranged reference points, the three second convex portions and the three second concave portions are alternately arranged,
A plurality of reference points on the first surface and a plurality of reference points on the second surface are intermediate portions in the thickness direction of the core material and are positioned one-on-one on the front and back sides. Body manufacturing method.

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