JP5107675B2 - Papermaking mold for hollow fiber moldings - Google Patents

Description

  The present invention relates to a papermaking mold suitably used in a papermaking process in a manufacturing process of a hollow fiber molded body made of pulp or the like.

  The present applicant has previously proposed a papermaking mold for use in the manufacture of a pulp mold molded body (see Patent Document 1). This papermaking mold includes a mold body having a concave papermaking portion that forms a cavity corresponding to a hollow molded body to be molded, and an outer edge portion that extends outward from the peripheral edge of the papermaking portion. On the surface of the papermaking portion of the mold main body, a lattice-shaped water passage groove is provided so that part or all of the end portions do not reach the outer edge portion. According to this papermaking mold, as shown in FIG. 8, since the end of the water flow groove does not reach the outer edge of the mold body, for example, a paper-made fiber product is made using compressed air or negative pressure air. Thus, when the paper mold is removed from the papermaking mold and delivered to the dry mold, there is an advantage that the fiber molded body can be delivered smoothly because there is no leakage of compressed air or the like from the water channel.

  In the papermaking mold, as shown in FIG. 8, the end of the water flow groove 105a is prevented from reaching the peripheral portion 130a ′ of the mold body 130. It is necessary to separate the vertical groove 105a ′ located closest to the peripheral edge portion 130a ′ by the distance Y between the peripheral edge portion 130a ′. In the papermaking mold configured as described above, the fibers F are easily deposited and clogged between the surface of the papermaking portion 130a and the papermaking net 131 covering the surface of the papermaking portion 130a. It may cause trouble in papermaking. This seems to be because the effect of compressed air or negative pressure air from the water channel cannot be obtained. In order to prevent this inconvenience, it is advantageous to make the formation position of the longitudinal groove 105a 'as close as possible to the peripheral edge portion 130a' of the papermaking portion 130a. However, if the formation position of the vertical groove is brought close to the peripheral portion 130a ′ of the papermaking portion 130a, the strength of the mold main body 130 at the peripheral portion 130a ′ is likely to be lowered, and this has an influence when the mold main bodies 130 are abutted with each other. May have an effect.

JP 2002-115200 A

  The objective of this invention is providing the papermaking type | mold of the hollow fiber molded object which can eliminate the fault which the prior art mentioned above has.

The present invention is a hollow fiber used as a pair, comprising: a concave paper-making part that forms a cavity corresponding to a hollow molded body to be molded; and a mold body that has a butting surface extending outward from the peripheral edge of the paper-making part. A papermaking mold for a molded body,
On the surface of the papermaking section, a grid-shaped water flow groove is provided,
Of the grid-shaped water flow grooves, the outermost edge groove that is positioned closest to the peripheral edge of the papermaking section and extends in the same direction as the peripheral edge extends is located on the side close to the peripheral edge. 1 side wall and a second side wall located on the side far from the peripheral edge,
The first side wall in the outermost edge groove is inclined from the opening end of the outermost edge groove toward the bottom, and the distance from the butted surface to the first side wall is from the opening end of the outermost edge groove. The present invention provides a papermaking mold for a hollow fiber molded body that gradually increases toward the bottom.

  According to the present invention, out of the lattice-shaped water flow grooves provided on the surface of the papermaking section of the mold body, the outermost edge groove located closest to the peripheral edge of the papermaking section is made as far as possible in the peripheral edge. Since they can be provided close to each other, it is difficult for fibers to be deposited between the surface of the papermaking portion and the papermaking net covering it during papermaking, and clogging is difficult to occur in the net. Further, since the mechanical strength at the peripheral portion is ensured, the peripheral portion can sufficiently withstand the impact of the abutting when the die main bodies are abutted with each other, and the durability of the die main body can be enhanced. .

  The present invention will be described below based on preferred embodiments with reference to the drawings. 1 to 3 show an embodiment of a papermaking mold (hereinafter also simply referred to as papermaking mold) of the hollow fiber molded body of the present invention. In the figure, reference numeral 1 denotes a papermaking mold.

  The papermaking mold 1 according to this embodiment is used as a pair, and papermaking a cylindrical bottle-shaped hollow molded body having a thread on the outer peripheral surface of the mouth and neck.

  As shown in FIG. 1, the papermaking mold 1 includes a back plate 2 fixed to a platen (not shown) of a mold clamping device, and a papermaking body 3 detachably attached to a front surface portion 20 of the back plate 2. I have. A flow passage 4 communicating with each other is formed in the back plate 2 and the papermaking body 3. This flow passage 4 is a discharge path for the liquid component in the pulp slurry at the time of papermaking, a supply path for compressed air at the time of washing the papermaking net 31 by purging compressed air before or during papermaking, or a drying mold. It functions as a compressed air supply path and a suction path leading to a negative pressure source during delivery of the molded body. The function of the flow passage 4 can be changed by switching the route according to the timing of each process, but a plurality of flow passages can be formed for each route corresponding to the function. In FIG. 1, the papermaking net 31 is drawn for convenience so that a part of the papermaking net 31 is cut out to expose the water flow groove 5 located below the papermaking net 31.

  The back plate 2 is fixed to a movable or fixed platen (not shown) of a so-called reciprocating type clamping device, and has a plate surface size slightly larger than that of the papermaking body 3, and is not shown in the drawing. It is fixed to the platen with bolts or the like. In the papermaking mold 1 of the present embodiment, two independent pipes 21 and 22 constituting the flow passage 4 are formed inside the back plate 2, and these pipes 21 and 22 are respectively One opening end portion is formed on the front surface portion 20 of the back plate 2, and the other opening end portion is formed on the bottom surface portion 23 of the back plate 2.

  As shown in FIG. 3, the papermaking body 3 is a gold having a concave papermaking portion 30a that forms a cavity corresponding to a hollow fiber molded body to be molded, and a butting surface 30b extending outward from the peripheral edge of the papermaking portion 30a. A mold body 30, a papermaking net 31 attached to the mold body 30 so as to cover the papermaking part 30a, and a fixing member 32 for fixing side edges of the papermaking net 31 on both sides of the mold body 30. I have. The papermaking body 3 is fixed to the back plate 2 by bolting the mold body 30 to the back plate 2.

  As shown in FIG. 2, the mold body 30 is assembled from three divided molds 30 </ b> A to 30 </ b> C that are divided at portions corresponding to the mouth-and-neck portion, the trunk portion, and the bottom portion of the hollow fiber molded body to be molded. Each of the divided molds can be attached to and detached from the back plate 2. As a result, when the design of the mouth neck and the bottom of the hollow molded body to be molded is partially changed, the divided mold can be replaced to easily cope with the design change. Moreover, maintenance such as cleaning can be easily performed by configuring the mold main body as a divided mold.

  Inside the mold body 30, two pipe lines 33 and 34 constituting the flow path 4 are formed. Each of the pipes 33 and 34 has an opening end at the mouth neck and bottom and a bottom of the molded body 30a, and the other opening end leads to the pipes 21 and 22 of the back member 2. An opening is formed in the back surface of the mold body 30. One open end 33a of the pipe line 33 is formed in a portion corresponding to the mouth and neck of the hollow molded body to be molded, and the one open end 34a of the pipe line 34 is formed at the bottom of the hollow molded body to be molded. It is drilled in the corresponding part. In this way, by providing the opening end 33a of the conduit 33 serving as the opening end of the flow passage 4 in a portion corresponding to the mouth and neck of the hollow molded body, the outer peripheral surface of the mouth and neck particularly has a thread. A sufficient thickness can be ensured when making a compact. Inside the split mold 30C, a manifold portion 34b is formed below the portion corresponding to the bottom of the hollow molded body to be molded, and even when the open end portion 34a of the pipe line 34 is increased, it can easily flow. Road 4 can be communicated.

  As shown in FIGS. 2 and 3, the surface of the papermaking portion 30a is provided with a grid-like water flow groove 5 so that the end thereof does not reach the abutting surface 30b, and passes through the papermaking net 31. The liquid content of the slurry can be smoothly discharged to the outside of the papermaking mold through the flow passage 4. Further, since the water flow grooves 5 are in a lattice shape, the stirring effect of the slurry in the cavity can be obtained, and the natural sedimentation of the solid content in the slurry is suppressed, so that even a vertically long hollow molded body has a uniform thickness Is easily obtained. The depth of the water flow groove 5 is preferably 0.5 to 100 mm, and more preferably 1 to 50 mm from the viewpoint of workability, drainage, and prevention of clogging of the papermaking net. The width of the water flow groove 5 is preferably 0.3 to 25 mm from the viewpoints of workability, drainage, prevention of clogging of the papermaking net, and ease of support of the papermaking net. More preferably, it is 10 mm. Furthermore, the lattice spacing of the water flow grooves is preferably 0.6 to 100 mm, and more preferably 2 to 50 mm.

  The papermaking net 31 has a mesh number of 10 to 200 mesh (JIS G3555, below) in terms of surface properties, releasability, water permeability, net strength (durability), resistance to dirt, and papermaking properties. The same)), and preferably 20 to 100 mesh. Further, the net for papermaking has an average maximum opening width of 0.05 to 10 mm in terms of the surface properties of the molded body, releasability, water permeability, net strength (durability), resistance to dirt, and papermaking properties. It is preferably 0.1 to 3 mm. The material for the papermaking net is preferably made of a metal such as stainless steel or brass, or a synthetic resin such as polyethylene terephthalate, polyethylene, polypropylene, or polytetrafluoroethylene.

  As shown in FIG. 3, the fixing member 32 is made of a metal plate, and the end face 32 a is bolted to the mold body 30 so as to form a butt surface with another corresponding papermaking mold (not shown). (Not shown). Thus, by making the front end surface portion 32a of the fixing member 32 a butting surface, the netting net 31 by repeated butting is obtained while ensuring the adhesion between the nets in the butting state and preventing the occurrence of burrs and the like on the butting surfaces. The direct damage can be suppressed. A groove 32b is formed in the end surface portion 32a of the fixing member 32, and a sealing member 32c is fitted into the groove 32b from the viewpoint of improving the sealing performance in the mold clamping state. An elastic body such as silicone rubber, fluorine rubber, or urethane rubber is preferably used for the seal member 32c. The grooves 32b and the seal member 32c may be disposed on one of the pair of papermaking molds.

  A gap is formed between the mold body 30 and the fixing member 32 to accommodate the side edge 31a of the papermaking net 31. In this gap, a presser plate 32d for holding the side edge 31a of the paper making net 31 from the outside is disposed, and the presser plate 32d is pressed by a screw 32f screwed into a screw hole 32e of the fixing member 32. By doing so, the side edge 31a of the papermaking net 31 can be fixed. The lower edge of the papermaking net 31 is sandwiched and fixed between the split molds 30B and 30C.

  As shown in FIG. 2, in this embodiment, a nozzle plate 35 is provided on the mold body 30 to maintain the sealing performance of a pulp slurry injection nozzle (not shown). The nozzle plate 35 is fixed to the front surface portion 20 of the back plate 2, and sandwiches the upper edge portion 31 b of the papermaking net 31 together with the mold body 30.

  In FIG. 4, the two mold main bodies 30 in the papermaking mold 1 shown in FIG. 1 are arranged in the lateral direction of the divided mold 30 </ b> B of the mold main body 30 in a state where the butted surfaces 30 b face each other. The cross section of is schematically shown. In the figure, the longitudinal groove 5a is shown among the water flow grooves 5 formed on the surface of the papermaking portion 30a of each mold body 30. The longitudinal groove 5a extends in the same direction as the direction in which the peripheral edge of the papermaking portion 30a extends, that is, in the vertical direction of the mold body (in the present embodiment, the direction from the divided molds 30A to 30C).

  FIG. 5 is an enlarged view of a main part in FIG. In FIG. 5, the papermaking net 31 is omitted. As shown in FIG. 5, in each mold main body 30, the vertical groove 5 a ′, which is the two outermost edge grooves located closest to the peripheral edge portion 30 a ′ of the papermaking portion 30 a among the vertical grooves 5 a, It has the 1st side wall 51 located in the side near 30a ', and the 2nd side wall 52 located in the side far from peripheral part 30a'. Further, the vertical groove 5 a ′ has a bottom 53.

The second side wall 52 in the longitudinal groove 5a ′ is a plane parallel to the butted surface 30b. Further, the bottom surface 53 of the longitudinal groove 5a ′ is a plane orthogonal to the abutting surface 30b. The first side wall 51 in the vertical groove 5a ′ is a flat surface inclined toward the bottom surface 53 from the opening end 54 of the vertical groove 5a ′. By this inclination, the distance D from the butted surface 30b to the first side wall 51 of the first side wall 51 is gradually increased from the opening end 54 of the vertical groove 5a ′ toward the bottom surface 53. . For example, the distance from the abutment surface 30b at the open end 54 to the first side wall 51 and D _1, and the distance from the abutment surface 30b of the bottom surface to the first side wall 51 and D _2, becomes D ₁ <D ₂ ing. This distance D increases continuously between D ₁ and D ₂ .

  Since the vertical groove 5a ′ has such a structure, the vertical groove 5a ′ can be provided as close as possible to the peripheral edge portion 30a ′ of the papermaking portion 30a. In the vicinity of the peripheral edge portion 30a ′, fibers are effectively deposited between the papermaking portion 30a and the papermaking net 31, and the net 31 is effectively prevented from being clogged. As a result, papermaking can be performed successfully. Further, since the mechanical strength at the peripheral edge portion 30a 'is ensured, the peripheral edge portion 30a' can sufficiently withstand the impact of the abutting when the die main bodies 30 are abutted with each other.

From the viewpoint of more effectively preventing the papermaking net 31 from being clogged, it is preferable that the distance D ₁ from the butted surface 30b at the opening end 54 to the first side wall 51 is 3 mm or less, particularly 1 mm or less. The distance D ₁ may be zero, depending on the difficulty of processing the first side wall 51 in the longitudinal groove 5a ′. However, considering the ease of processing and the like, the lower limit value of the distance D ₁ is preferably about 0.3 mm.

  In the longitudinal groove 5a ′, the fact that the first side wall 51 is inclined from the opening end 54 toward the bottom surface 53 over the entire length can surely prevent clogging of the papermaking net 31, and the mold body. It is particularly preferable from the viewpoint that the peripheral edge portion 30a ′ can sufficiently withstand the impact of the butting at the time of butting 30. However, even if the first side wall 51 is inclined from the opening end 54 toward the bottom surface 53 in a part of the entire length of the longitudinal groove 5a ′ within a range not impairing the effects of the present invention described above. Good. The same applies to the embodiments shown in FIGS. 6A to 6C described below.

  The shape of the first side wall 51 in the longitudinal groove 5 a ′ is not limited to that shown in FIGS. 4 and 5, and other shapes can be adopted. For example, as shown to Fig.6 (a), the 1st side wall 51 can be made to incline discontinuously stepwise. Further, as shown in FIGS. 6B and 6C, the first side wall 51 can be a curved surface and can be smoothly and continuously inclined. 6B and 6C, FIG. 6B shows a state in which the first side wall 51 is a concave curved surface, and FIG. 6C shows that the first side wall 51 is convex. This represents a state of a curved surface.

  The above description is about the split mold 30B in the mold body 30, but the split mold 30A and the split mold 30C, which are other split molds, are also divided in the same manner as the split mold 30B. Among the grid-shaped water flow grooves formed in the papermaking section, the outermost edge groove that is positioned closest to the peripheral edge of the papermaking section and extends in the same direction as the peripheral edge extends is as described above. It is preferable that

  Next, the papermaking process of the pulp mold hollow molded body using the papermaking mold 1 will be described with reference to FIG. 7 (a) to 7 (d) show the outline of the paper making / dehydration process of the molded body by the paper making mold 1, (a) is the pulp slurry injection / paper making process, and (b) is the core. An insertion process, (c) is a core pressurization / dehydration process, and (d) is a demolding process. In FIG. 7, for the sake of simplicity, the structure and shape of the papermaking mold are simplified.

  First, the end surfaces 32a of the fixing member 32 are brought into contact with each other to form a cavity C having a shape corresponding to the outer shape of the hollow molded body to be molded, as shown in FIG. Then, a slurry containing fibers is injected under pressure from the upper opening of the papermaking molds 1 and 1 '. For example, a pressure pump (not shown) can be used for the pressure injection of the slurry. The pressure for pressure injection of the slurry is preferably 0.01 to 5 MPa, more preferably 0.01 to 3 MPa.

  When the slurry is injected until the amount of slurry in the cavity C reaches a predetermined amount, suction / dehydration of the slurry through the flow passage 4 is started. As a result, moisture in the slurry is discharged to the outside of the papermaking mold 1 and fibers are deposited on the inner surface of the cavity C (the inner surface of the papermaking net), so that the hollow fiber deposit 6 is wet on the inner surface of the cavity C. Is formed.

  As fibers used in the slurry, for example, various kinds of wood pulp (virgin pulp and waste paper pulp), synthetic pulp, synthetic fiber, natural fiber, rayon fiber, etc. are used alone or in combination of two or more. Can do. The slurry may be composed only of fibers and water. In addition to fibers and water, inorganic powders such as graphite, obsidian, and mullite may be added. Moreover, you may add the inorganic fiber whose average fiber length is 0.5-15 mm, especially 3-8 mm, such as carbon fiber and artificial mineral fibers, such as rock wool, a ceramic fiber, and a natural mineral fiber. Furthermore, you may add components, such as a powder or fiber of thermoplastic synthetic resins, such as polyolefin, a non-wood or vegetable fiber, and a polysaccharide. Furthermore, you may add thermosetting resins, such as a phenol resin, an epoxy resin, and a furan resin. The total amount of these components is preferably 1 to 70% by weight, particularly 5 to 50% by weight, based on the total amount of the fibers and the components.

  After the fiber deposit 6 having a predetermined thickness is formed, the inside of the cavity C is sucked and depressurized through the flow passage 4 as shown in FIG. The hollow core 7 is inserted into the cavity C. The core 7 is used to give the inner shape of the cavity C by inflating like a balloon in the cavity C and pressing the wet fiber deposit 6 against the inner surface of the cavity C. The core 7 is preferably formed of a flexible film such as urethane, fluorine rubber, silicone rubber, or elastomer having excellent tensile strength, impact resilience, and stretchability.

  Next, as shown in FIG. 2C, a pressurized fluid is supplied into the core 7 to expand the core 7, and the fiber core 6 that has been wetted is expanded by the expanded core 7 to the inner surface of the cavity C. Press on. As a result, the fiber deposit 6 is pressed against the inner surface of the cavity C by the expanded core 7, the shape of the inner surface of the cavity C is transferred to the outer surface of the fiber deposit 6, and dehydration further proceeds. Further, since the wet fiber deposit 6 is pressed from the inside of the cavity C against the C inner surface of the cavity, even if the shape of the inner surface of the cavity is complicated, the inner surface of the cavity C is added to the outer surface of the fiber deposit. The shape is transferred with high accuracy. Moreover, since it is not necessary to use a bonding process, the resulting fiber deposit 6 has no joints and thick portions due to bonding. As a result, the strength of the molded body finally obtained is increased and the appearance impression is improved. As the pressurized fluid used for expanding the core 7, for example, compressed air (heated air), oil (heated oil), and other various liquids are used. Moreover, it is preferable that the pressure which supplies a pressurized fluid shall be 0.01-5 Mpa, especially 0.1-3 Mpa.

  When the shape of the inner surface of the cavity C is sufficiently transferred to the outer surface of the fiber deposit 6 and the fiber deposit 6 can be dehydrated to a predetermined moisture content, as shown in FIG. Remove the pressurized fluid. Then, the core 7 is automatically contracted and returned to the original size. Next, the contracted core is taken out from the cavity C, and the papermaking molds 1 and 1 'are opened to take out the undried fiber deposit 6 having a predetermined moisture content. The undried fiber deposit 6 thus taken out is then subjected to a pressing / drying step.

  The pressing / drying step of the fiber laminate 6 in an undried state is a well-known technique in the technical field, and for example, paragraphs in the specification of Japanese Patent Application Laid-Open No. 2002-115200 related to the earlier application of the present applicant [ This can be done in accordance with the description of [0030] to [0048] and FIGS. 5 to 12 of the drawings.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, the object to be manufactured in the above embodiment is a bottle having an open top, but a straight tubular body, a tubular body with an elbow, or the like may be used instead.

  Moreover, in the said embodiment, it provides in the papermaking type | mold 1 (refer FIGS. 1-3) so that all the edge parts of the water flow groove | channel 5 may not reach the abutting surface 30b, and this abutting surface 30b is another corresponding papermaking type | mold. In the state of butting against the butting surface 30b of the other papermaking type, it was made not to communicate with the water-groove of the other papermaking mold, but instead, all the water-grooves were provided so that both ends thereof reached the outer edge, In the state where it is in contact with the corresponding outer edge of another papermaking mold, the height of the water flow groove in each papermaking mold is staggered so as not to communicate with the waterflow groove of the other papermaking mold, or One end of the groove is provided so as to reach the abutting surface, and the opposite end of the water flow groove of another corresponding papermaking mold is provided so as not to reach the abutting surface. So that the water channels are not connected to each other. It is also possible.

It is the schematic perspective view which looked at one part which shows one Embodiment of the papermaking type | mold of the hollow fiber molded object of this invention. It is a schematic longitudinal cross-sectional view of the papermaking type | mold of the embodiment. It is a schematic cross-sectional view of the papermaking mold of the embodiment. It is a schematic diagram which shows the cross section of the horizontal direction in the split type | mold of this metal mold | die body in the state which has arrange | positioned two metal mold | die bodies in the papermaking type | mold shown in FIG. It is a principal part enlarged view in FIG. It is a figure (figure 5 equivalent figure) which shows other embodiment of the vertical groove provided in the metal mold body. It is the schematic which shows the papermaking and the spin-drying | dehydration process of the hollow fiber molded object using the papermaking type | mold shown in FIG. 1, (a) is a figure which shows a slurry injection | pouring and papermaking process, (b) is a figure which shows the insertion process in the inside, (C) is a figure which shows the press and dehydration process by a core, (d) is a figure which shows a demolding process. It is a figure (FIG. 5 equivalent figure) which shows the structure of the vertical groove provided in the metal mold | die main body in the papermaking type | mold of the conventional hollow fiber molded object.

Explanation of symbols

1. Papermaking mold (papermaking mold of hollow fiber molding)
2 Back plate 3 Papermaking body 30 Mold body 30a Papermaking part 30a 'Peripheral part of papermaking part 30b Abutting surface 31 Papermaking net 32 Fixing member 4 Flow path 5 Water flow groove 5a Vertical groove 5a' Near the peripheral part of papermaking part Vertical groove (outermost edge groove)
51 First side wall 52 Second side wall 53 Bottom surface 54 Open end of vertical groove

Claims (7)

A hollow fiber molded body used as a pair, comprising a mold body having a concave paper-making part forming a cavity corresponding to a hollow molded body to be molded, and a butting surface extending outward from the peripheral edge of the paper-making part. Molding,
On the surface of the papermaking section, a grid-shaped water flow groove is provided,
Of the grid-shaped water flow grooves, the outermost edge groove that is positioned closest to the peripheral edge of the papermaking section and extends in the same direction as the peripheral edge extends is located on the side close to the peripheral edge. 1 side wall, a second side wall located on the side far from the peripheral edge, and a bottom surface located between the first side wall and the second side wall ,
The second side wall of the outermost edge groove is a plane parallel to the abutting surface, and the bottom surface of the outermost edge groove is a plane orthogonal to the abutting surface;
The first side wall in the outermost edge groove is inclined from the opening end of the outermost edge groove toward the bottom, and the distance from the butted surface to the first side wall is from the opening end of the outermost edge groove. A papermaking mold for a hollow fiber molded body, which gradually increases toward the bottom surface . 2. The hollow fiber molded body according to claim 1, wherein the first side wall in the outermost edge groove is continuously inclined from the opening end of the outermost edge groove toward the bottom surface or is inclined stepwise. Molding.   The papermaking mold of the hollow fiber molded body according to claim 1 or 2, wherein a distance of the first side wall from the butted surface is 3 mm or less at an opening end of the outermost edge groove.   In a state where one mold body and the other mold body are in contact with each other, pass the water through the mold body so that the water flow groove of one mold body does not communicate with the water flow groove of the other mold body. The papermaking mold for a hollow fiber molded article according to any one of claims 1 to 3, wherein a water groove is provided.   The papermaking mold of the hollow fiber molded body according to any one of claims 1 to 4, wherein a part or all of the end portions of the water flow grooves are provided so as not to reach the abutting surface. The papermaking mold for a hollow fiber molded body according to any one of claims 1 to 5, wherein a distance of the first side wall from the abutting surface is 1 mm or less at an opening end of the outermost edge groove. The papermaking mold for a hollow fiber molded body according to any one of claims 1 to 6, wherein a distance of the first side wall from the abutting surface is 0.3 mm or more at an opening end of the outermost edge groove.

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