JP4368215B2 - Method and apparatus for producing cylindrical papermaking - Google Patents

Description

  The present invention relates to a method and an apparatus for producing a cylindrical papermaking body.

As a conventional technique related to the manufacture of a fiber tube, for example, a technique described in Patent Document 1 below is known.
This technique provides a fiber stream on two mesh belts that have apertures and can move continuously or intermittently along the inner surface of a tubular papermaking tube wall. The water in the fiber stream is removed by suction from a small hole provided in the tubular papermaking mold, and a seamless tubular papermaking body is continuously produced.

  By the way, this technique employs a mechanism that feeds a tubular paper product with a mesh belt along its length direction, so that a tubular paper product with a small diameter, particularly a thin paper product with a small diameter, can be manufactured. It is difficult.

JP 51-115319 A

  This invention is made | formed in view of the above-mentioned subject, and it aims at providing the manufacturing method and apparatus of a cylindrical papermaking body suitable also for manufacture of a thin and thin cylindrical papermaking body.

  The present invention is a method of manufacturing a tubular papermaking body by joining both side edges of the papermaking sheet, wherein the papermaking sheet and an expandable / contractable core body around which the papermaking sheet is wound are accommodated. While combining the split molds of the forming mold having a pair of split molds, the papermaking sheet is wound around the core body so that the side edges overlap with each other in the split mold, and then the core body is expanded. The object is achieved by providing a method for producing a cylindrical paper-making body in which the paper-making sheet is pressed against the forming surface of the mold and the side edges are joined together.

  The present invention also relates to an apparatus for producing a cylindrical papermaking for carrying out the method for producing a cylindrical papermaking of the present invention, wherein the papermaking means for papermaking and the papermaking sheet made by the papermaking means are provided. The present invention provides an apparatus for manufacturing a cylindrical paper-making body, which includes a stretchable core body to be wound and a forming die having a set of split molds around which the paper-making sheet is wound.

  According to the present invention, a thin and thin cylindrical paper-making body can also be suitably produced.

  Hereinafter, the present invention will be described based on preferred embodiments thereof.

  FIG.1 and FIG.2 shows one Embodiment of the manufacturing apparatus of the cylindrical papermaking body of this invention. In FIG. 1, the code | symbol 1 is the manufacturing apparatus (henceforth only a manufacturing apparatus) of a cylindrical papermaking body, 10 is a strip | belt-shaped papermaking sheet | seat, 11 has shown the cylindrical papermaking body.

  As shown in FIG. 1, the manufacturing apparatus 1 of this embodiment includes a papermaking means 2 for a belt-shaped papermaking sheet 10, an expandable core body 3 around which the papermaking sheet 10 is wound, and a papermaking sheet 10 wound around the core body 3. And forming means 4 for forming into a cylindrical shape. The manufacturing apparatus 1 includes a drying unit 5 that dries the cylindrical paper-making body 11 formed by the forming unit 4 and a stretchable sheet or net-like body that will be described later in the conveyance path of the belt-like paper-making sheet 10 that is made by the paper-making unit 2 Supply means 6 for supplying 10 '.

  The papermaking means 2 includes a storage tank 20 that stores the raw slurry, a papermaking drum 21 disposed in the storage tank 20, and a transport unit 22 that transports the papermaking sheet 10 made by the papermaking drum 21. The storage tank 20 and the papermaking drum 21 have the same configuration as that conventionally used in a papermaking sheet manufacturing apparatus by wet suction papermaking.

  The storage tank 20 is connected to the circulation path 202 together with the adjustment tank 200 and the pump 201. In the storage tank 20, the raw material slurry whose concentration is adjusted in the adjustment tank 200 is supplied by the pump 201, and a substantially constant amount of the raw material slurry is stored.

  The papermaking drum 21 is provided so as to rotate around the horizontal axis while a part of the outer peripheral surface thereof is immersed in the raw material slurry. The papermaking drum 21 is provided with a fluid flow passage (not shown) having one end opened on the outer peripheral surface thereof and the other end connected to a suction pump (not shown). A papermaking net 210 is disposed on the outer peripheral surface of the papermaking drum 21. The papermaking drum 21 rotates at a predetermined rotational speed, and the suction pump sucks the raw slurry through the flow passage, and the liquid content is discharged, and the solid content is deposited on the papermaking net 210. The paper sheet 10 is continuously made.

  The transport unit 22 includes a drive pulley 220, a pulley 221, a transport belt 222 wound around these pulleys, and a suction box 223 disposed inside the transport belt 222. The papermaking sheet 10 and the sheet or net-like body 10 ′ (hereinafter also referred to as the papermaking sheet 10 or the like) are driven by the driving pulley 220 while being attracted to the surface of the conveying belt 222 by the suction force generated by the suction box 223. It is conveyed by the conveyance belt 222 which rotates with it.

  As shown in FIG. 2, the core body 3 includes a hollow core tube 30 and inflatable and inflatable bag-like elastic pressing bodies 31 to 33 attached so as to partially enclose the core tube 30. ing. As shown in FIG. 1, the core body 3 is disposed substantially horizontally along the conveying direction of the papermaking sheet 10 and substantially along the conveying height of the papermaking sheet 10 by the conveying belt 222. The core body 3 is supported by a support body (not shown) so as not to fall.

  As shown in FIG. 2, the core tube 30 is provided with a flow hole 300 that communicates the inside and the outside. The rear end portion of the core tube 30 is connected to a suction pump (both not shown) via a flow passage 301. The other end of the flow passage 301 is connected to a fluid supply source and a suction pump via a switching valve (both not shown). When the fluid is supplied into the elastic pressing bodies 31 to 33 from the fluid supply source via the flow passage 301 and the flow hole 300, the core 3 expands, and the elastic pressing bodies 31 to 33 expand. When sucked by the suction pump through the hole 300, it contracts. Examples of the material of the elastic pressing bodies 31 to 33 include urethane, fluorine rubber, silicone rubber, and elastomer. Examples of the fluid for expanding the elastic pressing body 31 include compressed air (heated air), oil (heated oil), and other various fluids.

  As shown in FIG. 3, the molding means 4 includes a molding die 40 that also serves as a dehydrating die and an opening / closing mechanism (not shown) that opens and closes the molding die 40. The mold 40 includes a set (three in the present embodiment) of split molds 400 to 402. When these split molds are combined and closed, the core 3 and the core 3 are outside. A space for accommodating the wound papermaking sheet 10 is formed. A fluid flow passage 403 is connected to the split molds 400 to 402. Inside the split molds 400 to 402, there are provided flow passages 404, one end of which is open on the surface facing the papermaking sheet 10 and the other end and the other end of which leads to the flow passage 403. In order to obtain a cylindrical paper-making body having a surface roughness as described later, the surface roughness (Ra) of the inner surface of the split mold is preferably 15 μm or less, particularly 10 μm or less, more preferably 3 μm or less. The other end of the flow passage 403 is connected to a suction pump and a fluid supply source via a switching valve (both not shown). When the split molds 400 to 402 are sucked by the suction pump through the flow passages 403 and 404, the sheet-forming sheet 10 is adsorbed to the molding surface side, and the fluid supply source passes through the flow passages 403 and 404. When the fluid is supplied, the cylindrical papermaking body 11 is detached from the split mold.

As shown in FIG. 1, the drying means 5 includes a semi-drying mold 50, a main drying mold 51, and an opening / closing mechanism (not shown) that opens and closes these drying molds. Since the main drying mold 51 and the semi-drying mold 50 have the same configuration, the semi-drying mold 50 will be described below.
As shown in FIG. 4, the drying mold 50 includes a pair (in this embodiment, a pair) of split molds 500. When these split molds 500 are combined and the dry mold 50 is closed, A space is formed in which the formed tubular papermaking body 11 is accommodated together with the core body 3. A fluid flow passage 501 is connected to the split mold 500. Inside the split mold 500, there is provided a flow passage 502 having one end facing the cylindrical paper-making body 11 (hereinafter, this surface is also referred to as an inner surface) opened in a slit shape and the other end communicating with the flow passage 501. It has been. In order to obtain a cylindrical paper-making body having a surface roughness as will be described later, the surface roughness (Ra) of the inner surface of the split mold 500 is preferably 15 μm or less, particularly 10 μm or less, more preferably 3 μm or less. The other end of the flow passage 501 is connected to a suction pump and a fluid supply source via a switching valve (both not shown). Inside the split mold 500, a heater 503 for accelerating the drying of the tubular papermaking body 11 is disposed. When the fluid is supplied from the fluid supply source through the flow passages 501 and 502, the papermaking body is detached from the split mold 500.

  The length (length of the portion pressed by the elastic pressing bodies 31 to 33) L40, L50, and L51 of the molding die 40, the semi-drying die 50, and the main drying die 51 are designed to be substantially the same. Note that L40, L50, and L51 are set to appropriate lengths according to the conveyance pitch of the paper sheet produced by the conveyance unit 22 and the like.

  The manufacturing apparatus 1 includes a control unit (not shown) that operates the above-described units and the core body 3 in accordance with a predetermined sequence. The respective means and the core are operated so as to manufacture

  Next, the manufacturing method of the cylindrical papermaking body of this invention is demonstrated based on embodiment applied to manufacture of the cylindrical papermaking body used for manufacture of a casting using the manufacturing apparatus 1. FIG.

  First, as shown in FIG. 1, a wet strip-shaped sheet 10 is made from the raw slurry containing fibers by the sheet making means 2.

  The papermaking sheet 10 rotates a papermaking drum 21 having a part of the outer peripheral surface immersed in the raw material slurry, sucks the liquid content of the raw material slurry with the suction pump through the flow passage, and converts the solid component of the raw material slurry into the papermaking material. Paper is made by depositing on the net.

The components in the raw slurry and the blending thereof can be selected according to the use of the cylindrical papermaking to be produced.
Hereinafter, description will be made based on the case where the present invention is applied to the production of a cylindrical papermaking suitable for the production of a casting from molten metal.

The cylindrical papermaking produced in this embodiment contains organic fibers, inorganic fibers, inorganic particles, and a thermosetting resin.
The compounding ratio of the organic fiber, the inorganic fiber, the inorganic particle, and the thermosetting resin is a reduction in the amount of gas generated from the cylindrical papermaking when casting using the produced cylindrical papermaking, From the viewpoints of ease of removal of the cylindrical papermaking after the completion of casting, maintenance of heat resistance of the cylindrical papermaking itself, ease of molding, and the like, the organic fiber / the inorganic fiber / the inorganic particle / the thermosetting resin. = 10 to 70/1 to 80/10 to 70/10 to 70 (weight ratio), 15 to 50/5 to 50/20 to 60/10 to 50 (weight ratio), particularly 20 to 40/5 30/30 to 60/10 to 40 (weight ratio) is preferable.

  The organic fiber is a component that mainly forms a skeleton in a state before being used for casting in a cylindrical papermaking body and improves the moldability of the cylindrical papermaking body. In addition, when used for casting, some or all of the molten metal is burned by the heat of the molten metal, forming a void inside the cylindrical papermaking after the casting is manufactured, and improving the removability of the cylindrical papermaking. is there.

  Examples of the organic fibers include paper fibers, fibrillated synthetic fibers, and recycled fibers (for example, rayon fibers). These organic fibers can be used alone or in combination of two or more. Among these, paper fibers are particularly preferable because they can be formed into various forms by papermaking and sufficient strength can be obtained after dehydration and drying.

  Examples of the paper fiber include wood pulp, cotton pulp, linter pulp, bamboo straw and other non-wood pulp. As the paper fiber, these virgin pulp or waste paper pulp can be used alone or in combination of two or more. The paper fiber is particularly preferably used paper pulp from the viewpoints of easy availability, environmental protection, and reduction of manufacturing costs.

  The organic fiber has an average fiber length of 0.3 to 2.0 mm, particularly 0.5 to 1.5 mm, considering the formability, surface smoothness, and impact resistance of the cylindrical papermaking product.

  The blending ratio of the organic fiber in the cylindrical papermaking product is preferably 10 to 70 wt%, particularly 10 to 50 wt%, considering the moldability of the cylindrical papermaking product and the removability of the cylindrical papermaking product after the production of the casting.

  The inorganic fiber is a component that mainly forms a skeleton in a state before being used for casting in a cylindrical paper-making body, and maintains its shape without being burned by the heat of molten metal when used for casting. In particular, it is a component that suppresses thermal shrinkage that occurs when an organic component such as a thermosetting resin used in this embodiment is thermally decomposed by the heat of molten metal.

  Examples of the inorganic fibers include artificial mineral fibers such as carbon fibers and rock wool, ceramic fibers, and natural mineral fibers. These inorganic fibers can be used alone or in combination of two or more. Among these, it is preferable to use pitch-based or polyacrylonitrile (PAN) -based carbon fibers having high strength even at high temperatures from the viewpoint of effectively suppressing shrinkage associated with carbonization of the thermosetting resin, and in particular, PAN-based carbon. Fiber is preferred.

  The inorganic fiber has an average fiber length of 0.2 to 10 mm, particularly 0.5 to 8 mm from the viewpoints of dewaterability when the cylindrical papermaking is made and dehydrated, moldability of the cylindrical papermaking, and uniformity. preferable.

  The said inorganic fiber has a function which suppresses the heat shrink accompanying the thermal decomposition of a cylindrical papermaking body.

  The inorganic fiber is preferably blended in an amount of 5 to 200 parts by weight, particularly 10 to 100 parts by weight, based on 100 parts by weight of the organic fiber. By mix | blending inorganic fiber in such a range, heat resistance of a cylindrical papermaking body is fully maintained, and generation | occurrence | production of the casting surface defect by gas generation | occurrence | production can be suppressed.

  The inorganic particles are components that soften by the heat of the molten metal to form a refractory film and prevent the carbon film formed by the thermal decomposition of the thermosetting resin by the heat from being dissolved in the molten metal with a low carbon equivalent. Yes, it is a component that further improves the surface smoothness of the casting obtained by preventing the sand from adhering to the casting surface when casting sand is disposed outside the cylindrical papermaking body or inside the hollow core. In consideration of the moldability of the cylindrical papermaking and the surface smoothness of the casting, the inorganic particles should be 50 to 400 parts by weight, particularly 100 to 300 parts by weight, based on 100 parts by weight of the organic fiber in the blending ratio. Is preferred.

Examples of the inorganic particles include silica, alumina, mullite, magnesia, zirconia, mica, graphite, obsidian, and other inorganic particles having a fire resistance of 800 to 2000 ° C, preferably 1000 to 1700 ° C. Obsidian and mullite powder are preferred because they have a particularly high effect of preventing the dissolution of the carbon film in the molten metal. These inorganic particles may be used alone or in combination of two or more. The particle diameter of the inorganic particles is preferably 200 μm or less. In particular, inorganic particles having a fire resistance of ± 300 ° C., particularly ± 200 ° C. with respect to the casting temperature of the molten metal to be cast are preferable. Here, the fire resistance of the inorganic particles depends on a measuring method (JIS R2204) using a Zeger cone.

  Examples of the thermosetting resin include thermosetting resins such as phenol resins, epoxy resins, and furan resins. The thermosetting resin is a component necessary for maintaining the normal temperature strength and the hot strength and improving the surface roughness of the casting, and a surface smoothness equivalent to that of a sand mold coated with a coating agent is obtained. It is not necessary to use a coating agent. This is an important performance for the tubular papermaking product of the present invention containing organic fibers and the like that are difficult to ignite and dry when using conventional alcoholic coating agents.

  In particular, the thermosetting resin having such performance has little generation of combustible gas, has a combustion suppressing effect, has a high residual carbon ratio of 25% or more after pyrolysis (carbonization), and has a carbon film at the time of casting. It is preferable to use a phenol-based resin from the viewpoint that a good casting surface can be obtained for the formation. The residual carbon ratio can be determined from the residual weight after heating to 1000 ° C. in a reducing atmosphere (under a nitrogen atmosphere) by an analytical thermal analysis.

  Examples of the phenolic resin include novolak phenol resins, resol type phenol resins, modified phenol resins modified with urea, melamine, epoxy, and the like, preferably novolak phenol resins or modified resins thereof.

  The thermosetting resins may be used alone or in combination of two or more, and may be used in combination with an acrylic resin, a polyvinyl alcohol resin, or the like. In particular, when the tubular papermaking product of the present invention is applied to a hollow core, a high hot strength can be obtained by using a thermosetting resin (particularly a residual carbon ratio of 15% or more, particularly 25% or more). And the function as a hollow core can be sufficiently exhibited.

  The thermosetting resin is preferably blended in an amount of 30 to 300 parts by weight, particularly 50 to 200 parts by weight, per 100 parts by weight of the organic fiber in the blending ratio. By blending the curable resin in such a range, the surface roughness and shape retention of the casting can be improved.

  The thermosetting resin is coated on the organic fiber, the inorganic fiber or the inorganic particle, or powdered or emulsified and added to the raw material slurry. What binds inorganic fibers and the inorganic particles, impregnates after forming the formed body, and dries or hardens it to increase the strength of the cylindrical paper body, and carbonizes it by the heat of the molten metal during casting to maintain the strength, etc. Any form may be used as long as it can be carbonized by the heat of the molten metal during the subsequent casting to form a carbon film and contribute to maintaining the strength of the cylindrical papermaking and improving the surface smoothness of the casting. Good.

  Since the curing agent required when the novolak phenol resin is used is easily dissolved in water, it is preferably applied after dehydration of the molded body, particularly in the case of wet papermaking. It is preferable to use hexamethylenetetramine or the like as the curing agent.

  In addition to the organic fiber, the inorganic fiber, the inorganic particle, and the thermosetting resin, the cylindrical papermaking manufactured in the present embodiment includes polyvinyl alcohol, carboxymethyl cellulose (CMC), and polyamidoamine as necessary. Other components such as a paper strength reinforcing material such as epichlorohydrin resin, a polyacrylamide-based flocculant, and a colorant can be added at an appropriate ratio.

  When using the manufacturing apparatus 1 as shown in FIG. 1 as in this embodiment, the raw slurry has such fluidity that it can be supplied by a circulation pump after being adjusted in the adjustment tank through the circulation path. It is preferable.

  In this embodiment, a raw material slurry containing the organic fiber, the inorganic fiber, the inorganic particle, and the thermosetting resin at the predetermined blending ratio is prepared.

  Examples of the dispersion medium of the raw material slurry include water, white water, and solvents such as ethanol and methanol. Among these, from the viewpoints of papermaking / dehydration stability, quality stability, cost, ease of handling, etc. Water is particularly preferable.

  The total ratio of the fibers and inorganic particles to the dispersion medium in the raw slurry is 0.1 to 3 wt%, particularly 0.5 to 2 wt%, from the viewpoint of suppressing unevenness in the thickness of the papermaking and improving surface properties. % Is preferred.

  If necessary, additives such as the paper strength reinforcing material, the flocculant, and the preservative can be added to the raw material slurry at an appropriate ratio.

  Then, the raw slurry is sucked by the suction pump while the papermaking drum 21 is rotated, and the solid content is made to be volume on the papermaking net 210.

The liquid component content (weight content) of the papermaking sheet 10 made by the papermaking means 2 has a shape-retaining property as a sheet, and considering that the papermaking sheet is not damaged during transportation, etc., is 20 to 90 wt. %, Particularly 60 to 80 wt% is preferable. The basis weight of the papermaking sheet depends on the cylindrical papermaking body to be formed. For example, a tubular papermaking body having a level difference (in consideration of partial compression and stretching of the tubular papermaking body) In this case, 900 to 2000 g / m ² , particularly 1000 to 1200 g / m ² is preferable. Furthermore, the thickness of the papermaking sheet 10 is preferably 0.5 to 3 mm, particularly preferably 1 to 2 mm in the above-described relation.

  Next, the papermaking sheet 10 is intermittently conveyed by the conveyance belt 222. In the present embodiment, the sheet or mesh body 10 ′ is supplied to the transport path by the transport belt 222 by the supply means 7, and the stretchable sheet or mesh body 10 ′ is disposed on the back surface of the papermaking sheet 10. By disposing the stretchable sheet or the net-like body 10 ′ in this way, the wet papermaking sheet 10 is protected, so that it can be prevented from being damaged when the papermaking sheet 10 is transported or handled. In particular, when it is arranged on the back surface, the paper sheet can be easily conveyed and handled. The sheet or net 10 'can be disposed on the front surface or the back surface of the papermaking sheet 10 for the same reason.

  Considering that the stretchability of the sheet or net 10 ′ easily follows the shape of the papermaking sheet 10, it is preferably 120 to 200%.

The basis weight of the sheet, for the same reason as described above, 10 to 200 g / m ^2, especially 20 to 50 g / m ² preferably.
Examples of the material of the sheet include plant fibers including rayon, synthetic resin fibers such as nylon.

  The net-like body may be knitted so that the wire members constituting the mesh body are joined. Moreover, the wire itself may be knitted. Considering that the reticulate body easily follows the shape of the papermaking sheet 10, the wire diameter of the wire in an unstretched state is preferably 0.03 to 0.15 mm, and particularly preferably 0.05 to 0.1 mm. The opening area ratio in the state is preferably 70 to 95%, particularly preferably 85 to 90%. The material of the net-like body is the same as that of the sheet. However, if the biodegradability is important, it is preferable that the plant fiber is the main constituent. This is also true for the above-mentioned sheet.

  In consideration of the drying efficiency of the papermaking sheet 10, the sheet or net 10 ′ preferably has air permeability. The mesh is preferably about 7 to 10.

Next, the papermaking sheet 10 that has been conveyed intermittently is wound around the core 3 by the molding means 4.
The papermaking sheet 10 is wound around the core 3 in a state where the papermaking sheet 10 is stopped. First, as shown in FIG. 5A, the split mold 402 is raised and the split mold 402 and the core are wound. The papermaking sheet 10 is sandwiched between the body 3 and a part (lower part in the figure) of the papermaking sheet 10 is curved.

  Next, as shown in FIG. 5B, the split mold 400 moves horizontally to sandwich the papermaking sheet 10 between the split mold 400 and the core body 3, and the upper left portion of the papermaking sheet 10 is curved. Further, as shown in FIG. 5 (c), the split mold 401 moves horizontally to sandwich the papermaking sheet 10 between the split mold 401 and the core body 3 so that both side edges of the papermaking sheet 10 overlap each other. The upper right part of the papermaking sheet 10 is curved.

  Next, fluid is supplied into the elastic pressing body 31 through the flow passage 301 and the flow hole 300 of the core body 3, and the elastic pressing body 31 of the core body 3 expands. Then, the papermaking sheet 10 wound around the core 3 is pressed against the inner surface of the dehydrating die 50, and the liquid content of the papermaking sheet 10 is discharged to the outside through the flow passages 502, 501, so that the papermaking sheet 10 is cylindrical. The papermaking body 11 is dehydrated and molded.

  The pressing force of the papermaking sheet 10 by the core 3 at the time of dehydration molding by the molding die 40 is 0 in consideration of the drying efficiency of the papermaking sheet 10 and the physical properties such as surface properties, density, strength, etc. of the manufactured cylindrical papermaking body 11. .4 to 1.2 MPa, particularly 0.6 to 1 MPa is preferable. The liquid component content of the cylindrical paper body 11 formed by dehydration is 55 to 95 Wt%, particularly 60, considering that the tubular paper body 11 is deformed to some extent during drying to improve its surface properties and strength. It is preferable to set it to -80Wt%.

  After the dehydration molding is completed, the supply of fluid from the flow passage 301 is stopped, and the elastic pressing body 31 contracts. On the other hand, the cylindrical papermaking body 11 that has been dehydrated and molded by opening the mold 40 is detached from the mold 40. Then, the papermaking sheet 10 to be dehydrated and molded next is conveyed by the conveying belt 222 to the molding means 4, and the cylindrical papermaking body 11 that has been dehydrated and molded is conveyed to the drying means 5. In the molding means 4, dehydration molding from the papermaking sheet 10 to the cylindrical papermaking body 11 by the cooperation of the molding die 4 and the core body 3 is repeatedly performed.

  The dewater-molded cylindrical papermaking body 11 is placed in a semi-dry mold 50 as shown in FIG. Then, the fluid is supplied into the elastic pressing body 32 through the flow passage 301 and the flow hole 300 of the core body 3 and expands, and the cylindrical papermaking body 11 is pressed against the inner surface of the semi-drying mold 50 and the flow passage. The liquid of the cylindrical papermaking body 11 is discharged outside through 502 and 501, and the cylindrical papermaking body 11 is semi-dried.

  The semi-drying temperature (mold temperature) is preferably 90 to 170 ° C., particularly preferably 100 to 150 ° C. in consideration of reliable bonding of the overlapped portions of the papermaking body. In addition, the pressing force of the cylindrical paper-making body 11 by the core body 3 at the time of semi-drying is preferably 0.2 to 1.2 MPa, particularly 0.4 to 1 MPa, considering the ease of finishing in the subsequent process. The ratio (La / Lb) between the maximum outer diameter La after dehydration molding and the maximum outer diameter Lb after semi-drying is 1.0 to 1.1, particularly 1.0, from the viewpoint of improving the surface properties of the cylindrical papermaking. It is preferable to set it to -1.05.

  After the semi-drying is completed, the supply of fluid from the flow passage 301 is stopped, and the elastic pressing body 32 contracts. On the other hand, the semi-drying mold 50 is opened and the semi-dried cylindrical papermaking body 11 is detached from the semi-drying mold 50. The semi-drying mold 50 cooperates with the core body 3 in this manner, and performs semi-drying of the cylindrical papermaking body every time the cylindrical papermaking body 11 is arranged in the semidrying mold 50. Then, as the paper sheet 10 to be dewatered and molded next is transported to the forming means 4 by the transport belt 222, the semi-dried tubular paper body 11 is transported by the transport belt 222, and this dry mold 51.

  The main drying by the main drying mold 51 is performed in the same manner as the semi-drying by the semi-drying mold except that the drying conditions are different.

  The main drying temperature (mold temperature) is preferably 100 to 200 ° C., particularly 120 to 180 ° C. from the viewpoint of increasing the drying efficiency of the tubular papermaking body 11 so that it does not ignite. Further, the pressing force of the cylindrical papermaking body 11 by the core 3 during the main drying is 0.2 to 1.2 MPa, particularly 0.4 to 1 MPa in consideration of the drying efficiency and surface properties of the cylindrical papermaking body 11. preferable.

  After the main drying is completed, the supply of fluid from the flow passage 301 is stopped, and the elastic pressing body 33 contracts. On the other hand, the cylindrical papermaking body 11 that has been dried and opened by the main drying mold 51 is detached from the main drying mold 51. The main drying mold 51 cooperates with the core body 3 in this way, and performs the main drying of the cylindrical papermaking body every time the cylindrical papermaking body 11 is arranged in the main drying mold 51.

  The dehydration molding by the mold 40 in cooperation with the core 3 described above, the semi-drying by the semi-drying mold 50, and the main drying by the main drying mold 51 are performed in parallel.

  The fully dried cylindrical papermaking body 11 is transported to a subsequent process by the transporting conveyor 8 and, if necessary, after removal, cutting, trimming, coloring, printing, labeling, etc. of the sheet or the net-like body 10 ′. Processing is performed and the manufacture is completed.

  The cylindrical papermaking produced in the present embodiment can have an inner diameter of 5 to 30 mm, particularly 6 to 20 mm, depending on the portion used.

  Further, the thickness of the cylindrical papermaking produced in the present embodiment can be appropriately set according to the portion used, but the thickness at least in the portion in contact with the molten metal is 0.2 to 5 mm, particularly 0. By setting the thickness to 4 to 2 mm, the strength required when molding by filling the foundry sand is sufficient, and the shape function of the cylindrical paper-making body, particularly the structure such as the core (described later) can be maintained. . In addition to suppressing an increase in the amount of gas generated during casting and preventing the occurrence of surface defects in the casting, the molding time can be shortened and the manufacturing cost can be kept low.

  The cylindrical papermaking produced in the present embodiment can have a bending strength of 5 MPa or more, particularly 10 MPa or more, in a state before being used for casting.

  The cylindrical papermaking produced in this embodiment preferably has a surface roughness (Ra) of 20 μm or less, particularly 3 to 15 μm, more preferably 5 to 10 μm. By setting it as such surface roughness, the smoothness of the surface of the casting obtained can be made more excellent. Here, the surface roughness can be measured with a commercially available measuring device.

  When the cylindrical papermaking produced in this embodiment is produced through a papermaking process using a raw material slurry using water as a dispersion medium, it is necessary to reduce the amount of gas generated during casting as much as possible before casting. In the state, the water content (weight water content) is preferably 10% or less, particularly preferably 8% or less.

  The cylindrical papermaking body manufactured in the present embodiment can be applied to a core used in a main mold having a casting product-shaped cavity on the inner surface, or a pouring system member such as a runner. In particular, it has excellent hot compressive strength, high shape retention, and excellent removability after casting. It can also be applied to hollow cores that do not require filling. Moreover, since it can make the diameter thin when it is set as a pouring type | system | group member, the quantity of the hot water remaining in a runner etc. can be restrained small.

  Moreover, since the said cylindrical papermaking body is shape | molded by pressing on the inner surface of a dry mold with the said elastic press body from the inside, the smoothness of an inner surface and an outer surface is high. For this reason, when it uses for manufacture of a casting, the obtained casting becomes a thing excellent especially in surface smoothness.

  If necessary, the obtained cylindrical papermaking can be impregnated partially or entirely with a binder and heated to be thermally cured. Examples of the binder include colloidal silica, ethyl silicate, and water glass.

  Moreover, it is preferable that the cylindrical papermaking body is heat-treated in a reducing atmosphere at 150 to 300 ° C., particularly 200 to 250 ° C., to advance the curing of the thermosetting resin. By performing such a heat treatment, a cylindrical paper-making body having better shape retention can be obtained. In particular, it is also suitable when there are concerns about the occurrence of gas defects due to the material and shape of the casting. The degree of cure of the thermosetting resin by such heat treatment is preferably 30% or more, particularly 80% or more in terms of the amount of acetone insoluble in the thermosetting resin described below.

Specifically, the insoluble content of the thermosetting resin is determined as follows.
That is, about 5 g of a sample is taken from the cylindrical papermaking product, pulverized with a mill, and the weight (a) is precisely weighed. The ground sample is added to a container together with acetone and shaken sufficiently, and then left at room temperature. Next, the pulverized sample is sufficiently filtered with a filter paper (weight (c)) so that the pulverized sample does not remain in the container, and the filtered pulverized sample is dried together with the filter paper to obtain them (crushed sample and filter paper). ) (B) is precisely weighed. Then, based on the obtained weights (a) to (c) and the theoretical weight (d) of components other than the thermosetting resin in the pulverized sample, the insoluble content of the thermosetting resin ( %).
Insoluble content% = 100− (a− (b−d)) × 100 / (ad)

  As described above, according to the manufacturing method of the cylindrical papermaking body of the present embodiment, the belt-shaped papermaking sheet 10 is wound around the core body 3 and the core body 3 is expanded in the forming die 40 to be formed into a cylindrical shape. Therefore, a thin and thin-walled cylindrical papermaking can also be suitably produced.

  FIG. 6 shows another embodiment of the forming means of the papermaking sheet in the apparatus for producing a cylindrical papermaking of the present invention. In FIG. 6, portions common to the mold 40 of the molding unit 4 of the embodiment are given the same reference numerals, and descriptions thereof are omitted. Therefore, the description in the above embodiment is appropriately applied to a portion not particularly described.

  The mold 40 includes a set (four in this embodiment) of split molds 405 to 408. When these split molds are combined and closed, the core body 3 and the core body 3 are outside. A space for accommodating the wound papermaking sheet 10 is formed. A fluid flow path 403 is connected to the split molds 405 to 408. Inside the split molds 405 to 408, as with the flow path 404 in the above-described embodiment, a flow path (not shown) having one end open on the surface facing the papermaking sheet 10 and the other end leading to the flow path 403. Is provided.

  Winding of the papermaking sheet 10 or the like 10 around the core 3 by the molding die 40 is performed in a state where the movement of the papermaking sheet 10 is stopped. First, as shown in FIG. 6A, the split die 408 is raised. The papermaking sheet 10 is sandwiched between the split mold 408 and the core body 3, and the papermaking sheet 10 is curved.

  Hereinafter, in the order of FIGS. 6B, 6C, and 6D, the split molds 405, 406, and 407 move horizontally and downward, and the papermaking sheet 10 is moved between each split mold and the core body 3. The papermaking sheet 10 is finally sandwiched between the split mold 407 and the core body 3, and the papermaking sheet 10 is bent so that both side edges of the papermaking sheet 10 overlap each other.

  The present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  In the manufacturing method of the cylindrical papermaking body of this invention, raw material slurry is not restrict | limited to the said embodiment, The raw material slurry match | combined with the cylindrical papermaking body to be manufactured is used.

  Further, in the present invention, it is preferable to arrange a stretchable sheet or a net-like body as in the above embodiment, but these can be omitted. Moreover, there is no restriction | limiting in particular in how to arrange | position these sheets and net-like bodies. Like the said embodiment, you may distribute the said sheet | seat or a net-like body on the back surface of a strip | belt-shaped papermaking sheet | seat, and may distribute | arrange on the surface or both surfaces. Further, the stretchable sheet or net-like body disposed on the front surface or the back surface of the papermaking sheet may be cut into a predetermined size in advance.

  Further, as in the above-described embodiment, the production apparatus of the present invention is preferably sequentially dried with a semi-dry mold and a main dry mold after being dehydrated with a mold, but dehydration and drying may be performed with a mold. Good. Moreover, after adjusting a papermaking sheet to a desired liquid content rate, you may dry and shape | mold simultaneously using a dry type | mold as a shaping | molding die.

  In the present invention, depending on the use of the cylindrical paper to be produced, dry molding with a dry mold can be omitted. Also, either semi-drying or main drying can be omitted.

  Moreover, the curved cylindrical paper-making body can also be manufactured by making it the shape which curved the inner surface shape of the dry type | mold and the dehydration type | mold.

  The manufacturing method and apparatus of the cylindrical papermaking of the present invention are also used for manufacturing the cylindrical papermaking used for various interior materials and various model materials in addition to the cylindrical papermaking used for the production of castings as described above. Preferably used. Further, the present invention is suitable for the production of a thin and thin tubular paper-making body, but a tubular paper-making body having a thickness of 0.5 to 3 mm, an inner diameter of 5 to 30 mm, and a length of about 100 to 300 mm is also suitable. Can be manufactured.

It is a figure which shows typically one Embodiment of the manufacturing apparatus of the cylindrical papermaking body of this invention. It is a half sectional view which shows typically the core in the manufacturing apparatus of the cylindrical papermaking body of the embodiment. It is a fragmentary sectional view which shows typically the spin-drying | dehydration shaping | molding process in the manufacturing apparatus of the cylindrical papermaking body of the embodiment. It is a fragmentary sectional view which shows typically the drying process in the manufacturing apparatus of the cylindrical papermaking body of the embodiment. It is a figure which shows typically the operation | movement of the shaping | molding means in the manufacturing apparatus of the cylindrical papermaking body of the embodiment, (a) is a figure which shows the state which has introduced the papermaking sheet | seat into the shaping | molding means, (b) is a core body The figure which shows the state which has wound the papermaking sheet | seat in (c) is a figure which shows the state which winding was completed. It is a figure which shows typically operation | movement of the shaping | molding means in the manufacturing apparatus of the cylindrical paper-making body of other embodiment of this invention, (a) is a figure which shows the state which has introduce | transduced the paper-making sheet into the winding means, (b) And (c) is a figure which shows the state which has wound the papermaking sheet | seat around a core, (d) is a figure which shows the state which winding was completed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of cylindrical papermaking body 2 Papermaking means 3 Core body 4 Molding means 40 Molding die 5 Drying means 50 Drying type 10 Papermaking sheet 10 'Stretchable sheet or net body 11 Cylindrical papermaking body

Claims (6)

A method of manufacturing a tubular papermaking body by joining both side edges of a belt-like papermaking sheet conveyed in the longitudinal direction ,
While combining the split mold of the mold having a pair of split molds so as to accommodate the papermaking sheet and the expandable / contractable core around which the papermaking sheet is wound, overlapping manner, press the papermaking sheet, after wrapping around the core rounded to leave the width direction of the strip without cutting, the papermaking sheet on the molding surface of the mold by expanding the core body And the manufacturing method of the cylindrical papermaking body which joins the said both edge parts.   The manufacturing method of the cylindrical papermaking body of Claim 1 which has arrange | positioned the elastic sheet or net-like body on the said molding surface of the said shaping | molding die.   The manufacturing method of the cylindrical paper-making body of Claim 2 in which the said sheet | seat which can be expanded-contracted has air permeability.   The method for producing a cylindrical papermaking product according to any one of claims 1 to 3, wherein the molding die is a dehydrating die or a dry die.   An apparatus for producing a cylindrical papermaking body for carrying out the method for producing a tubular papermaking body according to claim 1, wherein the papermaking means for the belt-like papermaking sheet, and a stretchable core body around which the papermaking sheet is wound, An apparatus for producing a cylindrical papermaking body, comprising: a mold having a pair of split molds around which the papermaking sheet is wound around the core body.   The said core body is a manufacturing apparatus of the cylindrical papermaking body of Claim 5 provided with the hollow core pipe and the elastic press body which is attached to the outer side of this core pipe, a fluid is supplied inside, and expand | swells.

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