EP4269691A1 - Article façonné moulé en pâte fibreuse et son procédé de fabrication - Google Patents

Article façonné moulé en pâte fibreuse et son procédé de fabrication Download PDF

Info

Publication number
EP4269691A1
EP4269691A1 EP21910707.5A EP21910707A EP4269691A1 EP 4269691 A1 EP4269691 A1 EP 4269691A1 EP 21910707 A EP21910707 A EP 21910707A EP 4269691 A1 EP4269691 A1 EP 4269691A1
Authority
EP
European Patent Office
Prior art keywords
pulp
molded product
paper
mold
slurry
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21910707.5A
Other languages
German (de)
English (en)
Inventor
Megumi Ishii
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toppan Inc
Original Assignee
Toppan Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toppan Inc filed Critical Toppan Inc
Publication of EP4269691A1 publication Critical patent/EP4269691A1/fr
Pending legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
    • B65D1/34—Trays or like shallow containers
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J3/00—Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds

Definitions

  • the present invention relates to a pulp molded product.
  • gable top paper container which is a container that is made of a paper board coated with polyethylene resin on both surfaces and that has a gable roof-like top.
  • gable top paper container contributes to not only conservation of natural resources and energy but also to environmental conservation in that recycling and incineration are facilitated when disposed of. Therefore, a paper container is widespread in various fields.
  • the above-described paper container is formed by folding and bonding a paper board, the production process is complicated, and the production cost is increased. Also, since the flexibility in shape of the above-described paper container is low, there has been a problem in that, for example, the appeal of commercial products based on the container shape cannot be sufficiently exerted.
  • One of the techniques for increasing the flexibility in shape of a paper container is a pulp mold technique to produce a molded product from a slurry that contains pulp and water.
  • pulp in a slurry is generally deposited on a paper-making mold to form a pulp layer, and this pulp layer is dehydrated and thereafter dried in an oven.
  • the molded product obtained in this technique i.e., a pulp molded product, is excellent in heat resistance, cold resistance, moisture absorption and desorption, and others, which are characteristics in physical properties of paper-based packaging materials.
  • the pulp molded product has been put into wide use as a paper tray container for food products, a fixing and cushioning material for fruits or the like, and others (PTL 1).
  • a pulp molded product includes a surface that has unevenness with a large height difference. Such a pulp molded product is not suitable for a container that is required to have decorative properties in appearance. Also, in the pulp molded product, it is difficult to form a print layer or a coating layer.
  • An object of the present invention is to provide a technology that enables the production of a pulp molded product having an excellent surface property.
  • a pulp molded product including pulp and a surface having a region with an arithmetic average roughness Ra of 50 ⁇ m or less.
  • a method of producing a pulp molded product including: preparing a slurry that contains pulp having an average fiber length of less than 3.0 mm and water; depositing the pulp on a paper-making mold having a solid shape to form a pulp layer; dehydrating the pulp layer to obtain an undried intermediate molded product; and heating the undried intermediate molded product while sandwiching the intermediate molded product between a male mold and a female mold and applying pressure to the sandwiched intermediate molded product.
  • the "arithmetic average roughness Ra” is a surface property parameter defined in JIS B0601:2013.
  • the "average fiber length” is a length-weighted average fiber length L L defined in JIS P8226-2:2011 and measured by an optical automatic analysis method.
  • Fig. 1 is a diagram schematically illustrating an example of a production apparatus that can be used in producing a pulp molded product according to an embodiment of the present invention.
  • a production apparatus 1 illustrated in Fig. 1 includes a support body 10, a first station 20, a second station 30, and a third station 40.
  • the support body 10 includes a frame body and a rail which is disposed on the top of the frame body.
  • the first station includes a container 210, a raising and lowering device 220, a cover member 230, a paper-making mold 240, a moving device 250, a raising and lowering device 260, and an upper mold 270.
  • the container 210 is disposed in the frame body of the support body 10.
  • the container 210 opens at the top.
  • the container 210 houses a slurry S which contains pulp and water.
  • the raising and lowering device 220 is attached to the frame body of the support body 10 above the container 210.
  • the raising and lowering device 220 includes, for example, a hydraulic cylinder.
  • the raising and lowering device 220 supports the cover member 230.
  • the raising and lowering device 220 can raise and lower the cover member 230 in the position of the opening of the container 210.
  • the cover member 230 is a hollow body which has an opening at the top.
  • the cover member 230 is connected with an unillustrated pump.
  • the paper-making mold 240 is fixed to the opening of the cover member 230. Specifically, the paper-making mold 240 is fixed to the opening of the cover member 230 such that a space adjacent to one surface of the paper-making mold 240 is surrounded by the paper-making mold 240 and the cover member 230.
  • the paper-making mold 240 is a mold which has liquid permeability.
  • the paper-making mold 240 has a solid shape. That is, the paper-making mold 240 has one or more convex portions and/or one or more concave portions on a surface on which pulp is to be deposited.
  • the outer surface of the paper-making mold 240 i.e., the back surface of the surface adjacent to the above-described space, has a shape that corresponds to a pulp molded product.
  • the paper-making mold 240 is a male mold having a projected upper surface.
  • the paper-making mold 240 may include, for example, a paper-making mold main body that is disposed with multiple through holes and includes an outer surface having a shape corresponding to a pulp molded product, and a net body that is disposed on and along the outer surface of the paper-making mold main body.
  • the paper-making mold main body contains a hard material such as metal.
  • the moving device 250 can move along the rail of the support body 10 between the first station 20 and the second station 30.
  • the moving device 250 contains, as a power source, for example, a motor.
  • the moving device 250 is attached with the raising and lowering device 260 and can transfer this raising and lowering device 260 between the first station 20 and the second station 30.
  • the raising and lowering device 260 is, as described above, attached to the moving device 250.
  • the raising and lowering device 260 includes, for example, a hydraulic cylinder.
  • the raising and lowering device 260 supports the upper mold 270.
  • the raising and lowering device 260 can raise and lower the upper mold 270.
  • the upper mold 270 is a holder that sandwiches a later-described pulp layer between the upper mold 270 and the paper-making mold 240 and holds the pulp layer by a vacuum suction method.
  • the upper mold 270 contains a hard material such as metal.
  • the lower surface of the upper mold 270 has a shape corresponding to the above-described outer surface of the paper-making mold 240.
  • the upper mold 270 is a female mold having a concave lower surface.
  • the upper mold 270 has, for example, multiple through holes each opening on the lower surface at one end and being connected to the pump at the other end.
  • the second station 30 is disposed near the first station 20.
  • the second station 30 includes a base 310, a lower mold 320, a moving device 330, a press device 340, and an upper mold 350.
  • the base 310 is disposed in the frame body of the support body 10.
  • the lower mold 320 is disposed on the base 310.
  • the lower mold 320 is a mold that has gas and/or liquid permeability.
  • the lower mold 320 contains a hard material such as metal.
  • the upper surface of the lower mold 320 has a shape corresponding to the above-described outer surface of the paper-making mold 240.
  • the lower mold 320 is a male mold having a projected upper surface.
  • the lower mold 320 has multiple through holes, and the surface having a shape corresponding to the above-described outer surface of the paper-making mold 240 is smooth.
  • the moving device 330 can move along the rail of the support body 10 between the second station 30 and an unillustrated fourth station.
  • the moving device 330 contains, as a power source, for example, a motor.
  • a power source for example, a motor.
  • the up and down, left and right, and back and forth movements of the moving device 330 can be controlled by a locking mechanism.
  • the moving device 330 is attached with the press device 340 and can transfer this press device 340 between the second station 30 and the fourth station.
  • the press device 340 is, as described above, attached to the moving device 330.
  • the press device 340 includes, for example, a hydraulic cylinder.
  • the press device 340 supports the upper mold 350.
  • the press device 340 can raise and lower the upper mold 350.
  • the upper mold 350 is a mold that has neither gas permeability nor liquid permeability.
  • the upper mold 350 contains a hard material such as metal.
  • the lower surface of the upper mold 350 has a shape corresponding to the above-described outer surface of the paper-making mold 240.
  • the upper mold 350 is a female mold having a concave lower surface.
  • the surface having a shape corresponding to the above-described outer surface of the paper-making mold 240 is smooth.
  • the second station 30 further includes a heater and a pump (both are unillustrated).
  • the heater heats at least one of the lower mold 320 and the upper mold 350.
  • the pump is connected to the bottom space of the lower mold 320.
  • the third station 40 is disposed near the second station 30.
  • the third station 40 includes a base 410, a moving device 420, a raising and lowering device 430, and a holder 440.
  • the base 410 is disposed in the frame body of the support body 10.
  • a pulp molded product is to be disposed on the base 410.
  • the moving device 420 can move along the rail of the support body 10 between the second station 30 and the third station 40.
  • the moving device 420 contains, as a power source, for example, a motor.
  • the moving device 420 is attached with the raising and lowering device 430 and can transfer this raising and lowering device 430 between the second station 30 and the third station 40.
  • the raising and lowering device 430 is, as described above, attached to the moving device 420.
  • the raising and lowering device 430 includes, for example, a hydraulic cylinder.
  • the raising and lowering device 430 supports the holder 440.
  • the raising and lowering device 430 can raise and lower the holder 440.
  • the holder 440 is a holder that holds a later-described pulp molded product by a vacuum suction method.
  • the lower surface of the holder 440 has a shape corresponding to the above-described outer surface of the paper-making mold 240.
  • the lower surface of the holder 440 has a concave shape.
  • the holder 440 has, for example, multiple through holes each opening on the lower surface at one end and being connected to the pump at the other end.
  • a pulp molded product is produced, for example, using the above-described production apparatus 1. This will be described with reference to Figs. 1 to 9 .
  • Fig. 2 is a diagram illustrating a pulp layer forming step in pulp molding using the apparatus in Fig. 1 .
  • Fig. 3 is a cross-sectional view schematically illustrating an example of a pulp layer formed on a paper-making mold.
  • Fig. 4 is a diagram illustrating a dehydration step in pulp molding using the apparatus in Fig. 1 .
  • Fig. 5 is a diagram illustrating a pulp layer conveying step in pulp molding using the apparatus in Fig. 1 .
  • Fig. 6 is a diagram illustrating a hot pressing step in pulp molding using the apparatus in Fig. 1 .
  • Fig. 7 is a cross-sectional view schematically illustrating an example of a pulp molded product obtained by a hot pressing step.
  • Fig. 8 is a diagram illustrating a pulp molded product conveying step in pulp molding using the apparatus in Fig. 1 .
  • Fig. 9 is a diagram illustrating a state in which the conveying step of Fig. 8 has been
  • a slurry S is firstly prepared.
  • the slurry S contains, as described above, pulp and water.
  • the slurry S is a suspension which contains pulp dispersed in water and has a high viscosity.
  • the type of pulp used in the slurry S is not particularly limited.
  • chemical pulp is preferably used.
  • usable pulps are pulps usually used as raw pulps in paper making, including: wood pulps such as needle bleached kraft pulp (NBKP) or needle unbleached kraft pulp (NUKP) and leaf bleached kraft pulp (LBKP) or leaf unbleached kraft pulp (LUKP); and non-wood pulps such as straw, cotton, kenaf, bamboo, and sugarcane. These pulps can be used singly or as a mixture of two or more at an optional ratio.
  • NNKP needle bleached kraft pulp
  • NUKP needle unbleached kraft pulp
  • LKP leaf bleached kraft pulp
  • LKP leaf unbleached kraft pulp
  • non-wood pulps such as straw, cotton, kenaf, bamboo, and sugarcane.
  • Pulp has an average fiber length of less than 3.0 mm. This average fiber length is preferably 1.7mm or less.
  • the pulp molded product obtained with pulp having a long average fiber length cannot include a surface that has a region with a small arithmetic average roughness Ra.
  • the pulp molded product obtained by using pulp having a short average fiber length and sequentially performing later-described steps can include a surface that has a region with a small arithmetic average roughness Ra.
  • the average fiber length of pulp is preferably 0.5 mm or more and more preferably 0.7 mm or more.
  • a hot pressing step is performed to the undried pulp layer. That is, a hot pressing step is performed to the pulp layer having a large water content. Therefore, when the average fiber length of pulp is excessively short, variation in water evaporation rate is likely to occur in a hot pressing step and cause uneven shrinkage when dried, which can become a factor for wrinkles, cracks, or reduced strength.
  • the average fiber length of pulp can be adjusted by an optional method, for example, by a mechanical treatment such as beating or crushing.
  • the pulp content of the slurry S is preferably in a range of 0.01 to 3.0% by mass and more preferably in a range of 0.01 to 0.5% by mass.
  • the pulp content is small, high productivity is unlikely to be achieved.
  • the pulp content is large, there is a possibility that the thickness variance of the pulp layer may become large.
  • the slurry S can further contain an additive.
  • the additive to be used may be an organic polymer, inorganic particles, or a combination thereof.
  • the ratio of the additive relative to the total of pulp and the additive is preferably 10% by mass or less and more preferably 5% by mass or less. That is, the ratio of pulp relative to the total solid content of the slurry S is preferably 90% by mass or more and more preferably 95% by mass or more.
  • the slurry S is supplied into the container 210.
  • the cover member 230 is lowered by the raising and lowering device 220, such that the upper surface of the paper-making mold 240 is positioned sufficiently below the liquid surface of the slurry S.
  • the pump is driven in this state to decompress a space surrounded by the cover member 230 and the paper-making mold 240. This causes the occurrence of a flow of the slurry S crossing the paper-making mold 240, so that pulp is deposited on the paper-making mold 240.
  • a pulp layer MP1 is formed on the paper-making mold 240 as illustrated in Fig. 3 .
  • the cover member 230 is raised by the raising and lowering device 220, such that the bottom of the paper-making mold 240 is positioned sufficiently above the liquid surface of the slurry S. Accordingly, the pulp layer MP1 is dehydrated under reduced pressure.
  • the raising and lowering device 260 is driven to lower the upper mold 270 until the lower surface thereof is brought into contact with the pulp layer MP1. It is noted that the pulp layer MP1 is not drawn in Fig. 4 . This dehydration step is performed without heating either the upper mold 270 or the paper-making mold 240.
  • the decompression time in the dehydration step is preferably in a range of 1 to 60 seconds and more preferably in a range of 1 to 10 seconds.
  • the water content of the pulp layer MP1 immediately after dehydration is preferably in a range of 40 to 90% by mass and more preferably in a range of 50 to 70% by mass.
  • the water content is small, there is a possibility that in the hot pressing step, movement of fiber in the in-plane direction in the pulp layer may be insufficient.
  • the water content is large, there is a possibility that in the hot pressing step, movement of fiber in the in-plane direction in the pulp layer may be excessive, or the shape retention of the pulp layer MP1 may be insufficient in a period from the end of the dehydration step to the start of the hot pressing step.
  • the pump is driven to allow the upper mold 270 to suction and hold the pulp layer MP1. It is noted that the suction by the pump and the upper mold 270 does not cause further dehydration of the pulp layer MP1.
  • the raising and lowering device 260 is driven while the upper mold 270 is allowed to suction and hold the pulp layer MP1, to thereby raise the upper mold 270 as illustrated in Fig. 1 . Accordingly, the pulp layer MP1 is peeled from the paper-making mold 240.
  • the moving devices 250 and 330 are driven to move the press device 340 and the upper mold 350 from the second station 30 to the fourth station as well as the raising and lowering device 260 and the upper mold 270 from the first station 20 to the second station 30, as illustrated in Fig. 5 .
  • the raising and lowering device 260 is driven to lower the upper mold 270 until the pulp layer MP1 is brought into contact with the lower mold 320.
  • the suction by the pump and the upper mold 270 is terminated to release the pulp layer MP1 from the upper mold 270.
  • the raising and lowering device 260 is driven to raise the upper mold 270. In this manner, the pulp layer MP1 is transferred from the first station 20 to the second station 30, and the pulp layer MP1 is placed on the lower mold 320.
  • the moving devices 250 and 330 are driven to move the raising and lowering device 260 and the upper mold 270 from the second station 30 to the first station 20 as well as the press device 340 and the upper mold 350 from the fourth station to the second station 30, as illustrated in Fig. 1 .
  • the press device 340 is driven to lower the upper mold 350 as illustrated in Fig. 6 .
  • the pulp layer MP1 sandwiched between the upper mold 350 and the lower mold 320 is pressurized by the upper mold 350 and the lower mold 320.
  • the heater is driven to heat the pulp layer MP1.
  • the pump is driven to suction and remove water and/or water vapor from a space sandwiched by the upper mold 350 and the lower mold 320. Accordingly, the surface shape of the pulp layer MP1 is adjusted, and the pulp layer MP1 is densified and dried.
  • a pulp molded product MP2 illustrated in Fig. 7 is obtained.
  • water content of the pulp layer MP1 immediately before the start of this hot pressing step is substantially equal to the water content of the pulp layer MP1 immediately after the end of the dehydration step.
  • the press pressure in this hot pressing step is preferably 0.1 MPa or more and more preferably 0.3 MPa or more.
  • the press pressure is preferably 1.5 MPa or less and more preferably 1.0 MPa or less.
  • the press pressure is excessively high, the pulp molded product MP2 is likely to have variation in thickness.
  • the heating temperature of the pulp layer MP1 i.e., the temperature of the upper mold 350 or the lower mold 320 for heating by the heater, is preferably in a range of 120 to 250°C and more preferably in a range of 150 to 210°C.
  • the heating temperature is low, a long time is required to dry the pulp layer MP1.
  • the heating temperature is increased, there is a possibility that the shrinkage of the pulp layer MP1 associated with drying may increase and consequently the distortion in the pulp molded product MP2 may increase.
  • heating by the heater may be performed to either only one or both of the upper mold 350 and the lower mold 320.
  • the temperatures of the upper mold 350 and the lower mold 320 become substantially equal by heat conduction from one to the other. Therefore, in either case, drying of the pulp layer MP1 proceeds substantially simultaneously over the entire thickness. Accordingly, distortion caused by a difference in drying rate does not occur in the pulp molded product MP2.
  • the press time in the hot pressing step is preferably in a range of 10 to 300 seconds and more preferably in a range of 20 to 200 seconds, depending on the heating temperature, the shape of a molded product, and others.
  • the press device 340 is driven to raise the upper mold 350 so that the pulp molded product MP2 is peeled from the upper mold 350.
  • the moving devices 330 and 420 are driven to move the press device 340 and the upper mold 350 from the second station 30 to the fourth station as well as the raising and lowering device 430 and the holder 440 from the third station 40 to the second station 30, as illustrated in Fig. 8 .
  • the raising and lowering device 430 is driven to lower the holder 440 until the holder 440 is brought into contact with the pulp molded product MP2.
  • the pump is driven to allow the holder 440 to suck and hold the pulp molded product MP2.
  • the raising and lowering device 430 is driven while the holder 440 is allowed to suction and hold the pulp molded product MP2, to thereby raise the holder 440.
  • the moving devices 330 and 420 are driven to move the raising and lowering device 430 and the holder 440 from the second station 30 to the third station 40 as well as the press device 340 and the upper mold 350 from the fourth station to the second station 30, as illustrated in Fig. 9 .
  • the suction by the pump and the holder 440 is terminated to release the pulp molded product MP2 from the holder 440.
  • the pulp molded product MP2 is transferred from the second station 30 to the third station 40, and the pulp molded product MP2 is placed on the base 410.
  • the pulp molded product MP2 is subjected to post-treatment, for example, printing such as picture printing or plain printing, coating, or a combination thereof, as necessary.
  • post-treatment for example, printing such as picture printing or plain printing, coating, or a combination thereof, as necessary.
  • a coating layer to be formed by post-treatment include a layer that contains an agent to add water resistance or oil resistance, a layer that is filled with a material to add heat insulation, a layer that is foamed by a foaming agent, and a combination thereof.
  • the pulp molded product MP2 obtained by the above-described method has an excellent surface property. Reasons thereof will be described below.
  • the dehydration step is followed by drying the product with an oven, humidifying the dried product as necessary, and performing a hot pressing treatment to this product
  • the height difference of unevenness which occurred on the surface in association with drying can be reduced by the subsequent humidification and hot pressing treatment.
  • the porosity can be decreased by the humidification and hot pressing treatment.
  • the height difference of unevenness that occurs on the surface in association with drying with an oven is extraordinarily large, it cannot be sufficiently reduced by the subsequent humidification and hot pressing treatment.
  • even when drying is followed by humidification and hot pressing treatment it is difficult to sufficiently decrease the porosity.
  • the pulp layer MP1 is dried in a hot pressing step. That is, in the above-described method, a hot pressing step is performed after a dehydration step without undergoing a drying step. Also, as pulp, pulp having an average fiber length in the above-described range is used.
  • the pulp molded product MP2 having an excellent surface property can be produced. Specifically, there can be obtained the pulp molded product MP2 including a surface that has a region with an arithmetic average roughness Ra of 50 ⁇ m or less. Such a pulp molded product MP2 is excellent in decorative properties and facilitates the formation of a print layer and a coating layer.
  • the arithmetic average roughness Ra is preferably 40 ⁇ m or less.
  • the lower limit of this arithmetic average roughness Ra is not particularly limited but usually 20 ⁇ m or more.
  • the entire surface may have the above-described surface property, or only a partial region of the surface may have the above-described surface property.
  • a region that contains a portion to be subjected to a post-treatment such as printing may have the above-described surface property, and other regions may not have the above-described surface property.
  • one surface of the pulp molded product MP2 may have the above-described surface property, and the back surface thereof may not have the above-described surface property.
  • Such a structure can be achieved when, for example, a surface property differs between a partial region and the remaining region of the surfaces of the upper mold 350 and the lower mold 320 which are in contact with the pulp layer MP1.
  • a pulp molded product MP2 having a sufficiently small standard deviation of basis weight.
  • the standard deviation of basis weight of the pulp molded product MP2 is preferably less than 30 g/m 2 , more preferably 25 g/m 2 or less, and further preferably 20 g/m 2 or less.
  • the lower limit of this standard deviation is zero, 5 g/m 2 in one example, 8 g/m 2 in another example, and 10 g/m 2 in still another example.
  • the standard deviation of basis weight of the pulp molded product MP2 is a value obtained by the following method.
  • test pieces are cut out from multiple regions positioned in a certain in-plane of the pulp molded product MP2.
  • Each of the test pieces has a strip shape with a width of 15 mm and a length of 40 mm.
  • the masses of these test pieces are measured.
  • the basis weight of each of the test pieces is calculated from the mass and area (600 mm 2 ). From the thus-obtained basis weight, a standard deviation is calculated.
  • test pieces are cut out from multiple regions positioned in another in-plane of the pulp molded product MP2.
  • measurement of mass and calculation of basis weight and its standard deviation are similarly performed.
  • each of the remaining planes is also subjected to cutting out of test pieces, measurement of mass, and calculation of basis weight and its standard deviation, similarly to the above.
  • the present inventors consider that the pulp molded product MP2 having a small standard deviation of basis weight can be produced according to the method (hereinafter, referred to as a first method) described with reference to Fig. 1 to Fig. 9 , for the following reasons.
  • the pulp molded product can also be produced by, for example, the below-described method (hereinafter, referred to as a second method).
  • a female mold is firstly prepared as a paper-making mold.
  • This paper-making mold includes a paper-making mold main body that is disposed with multiple through holes and includes an upper surface having a shape corresponding to a pulp molded product, and a net body that is disposed on and along the inner surface of the paper-making mold main body.
  • this paper-making mold is disposed with its opening facing upward. Subsequently, a slurry that contains pulp and water is supplied into the cavity of the paper-making mold and fills the inside of the paper-making mold. Furthermore, the supply of the slurry into the paper-making mold is continued to deposit pulp on the net body. The supply of the slurry into the paper-making mold is performed such that the slurry in the paper-making mold is pressurized.
  • the supply of the slurry into the paper-making mold is terminated. Subsequently, water remaining in the paper-making mold is drained from the paper-making mold. For example, compressed air may be applied into the paper-making mold to allow water remaining in the paper-making mold to be drained from the paper-making mold.
  • the pulp layer is pressed by the paper-making mold and an upper mold as a male mold to dehydrate the pulp layer.
  • This dehydration step is performed without heating either the upper mold or the paper-making mold.
  • the water content of the pulp layer immediately after dehydration corresponds to the water content of the pulp layer MP1 immediately after dehydration in the first method.
  • the upper mold is allowed to suction and hold the pulp layer, and the upper mold is raised in this state. Accordingly, the pulp layer is peeled from the paper-making mold.
  • the upper mold which suctions and holds the pulp layer, is moved to the position of a lower mold as a female mold. Subsequently, the upper mold is lowered until the pulp layer is brought into contact with the lower mold. Thereafter, the suction is terminated to release the pulp layer from the upper mold. In this manner, the pulp layer is placed on the lower mold.
  • the pulp layer is placed between an upper mold and the lower mold for hot pressing, and the sandwiched pulp layer is pressurized.
  • a heater is driven to heat the pulp layer.
  • a pump is driven to suction and remove water and/or water vapor from a space sandwiched by the upper mold and the lower mold.
  • a pulp molded product is obtained in the above-described manner.
  • the flow of the slurry circulating in the paper-making mold can occur, in a period from when the supply of the slurry into the paper-making mold starts until the inside of the paper-making mold is completely filled with the slurry.
  • This circulating flow can prevent the sedimentation of pulp.
  • the inside of the paper-making mold needs to be filled with the slurry and therefore the structure of allowing water to be quickly drained cannot be adopted for the paper-making mold. Therefore, after the inside of the paper-making mold has been completely filled with the slurry, sufficient circulating flow of the slurry to prevent sedimentation of pulp does not occur even when the pressure of the slurry is increased, and sedimentation of pulp occurs in the slurry in the paper-making mold.
  • the amount of pulp deposited on the side wall of the paper-making mold is larger in the lower part than in the upper part.
  • the slurry is supplied until a sufficient amount of pulp is deposited above the side wall of the paper-making mold, an excessive amount of pulp comes to be deposited on the bottom of the paper-making mold.
  • the deposited amount of pulp increases in variance. For example, a large difference in the deposited amount of pulp can occur between vicinities of the through holes disposed to the paper-making mold main body and positions further from the through holes.
  • the paper-making mold 240 is disposed on the top of the cover member 230, and a composite thereof is immersed in the slurry S.
  • the depth of the slurry S is far larger than the height of the paper-making mold 240. Therefore, even if the sedimentation of pulp occurs in the slurry S, the concentration of pulp does not significantly differ between the position of the top of the paper-making mold 240 and the position of the bottom of the paper-making mold 240. Therefore, according to the first method, pulp can be substantially uniformly deposited on the paper-making mold 240 and thus the pulp molded product MP2 having a sufficiently small standard deviation of basis weight can be produced.
  • the pulp molded product MP2 has an opening and is not enlarged in diameter toward a direction away from this opening.
  • the pulp molded product MP2 has an opening and tapers toward a direction away from this opening. According to such a shape, the volume of a laminate obtained by laminating a plurality of pulp molded products MP2 can be reduced.
  • the pulp layer MP1 is sandwiched between one of the upper mold 350 and the lower mold 320 and an elastic body and then pressurized, instead of pressurizing the pulp layer MP1 by the upper mold 350 and the lower mold 320, the elastic body is deformed. Therefore, sufficient pressure is not applied to the pulp layer MP1 and thus the pulp molded product having an excellent surface property cannot be obtained.
  • the pulp molded product MP2 is, for example, a container.
  • the pulp molded product MP2 may be an article other than a container.
  • the pulp molded product MP2 is not particularly limited as long as it is a solid molded product, i.e., a molded product that does not have a two-dimensional shape such as a sheet but has a three-dimensional shape.
  • Fig. 1 to Fig. 9 are for facilitating understanding of the method of producing a pulp molded product according to an embodiment of the present invention.
  • the above-described method can also be performed using a production apparatus having other structures.
  • the upper mold 270 and the upper mold 350 are female molds
  • the paper-making mold 240 and the lower mold 320 are male molds.
  • the upper mold 270 and the upper mold 350 may be male molds
  • the paper-making mold 240 and the lower mold 320 may be female molds.
  • the above-described production apparatus 1 and production method can be variously modified.
  • a slurry that contains pulp and water was prepared.
  • pulp softwood pulp having an average fiber length of 2.3 mm was used.
  • the slurry was prepared such that the pulp content was 0.3% by mass.
  • a pulp molded product was produced by the first method described with reference to Fig. 1 to Fig. 9 .
  • the dehydration step was performed such that the water content of the pulp layer immediately after dehydration became 65% by mass.
  • the hot pressing step was performed under the conditions of a heating temperature of 150°C, a press pressure of 0.5 MPa, and a press time of 180 seconds.
  • a pulp molded product was produced by the same method as in Example 1, except that bamboo pulp having an average fiber length of 1.6 mm was used instead of softwood pulp having an average fiber length of 2.3 mm.
  • a pulp molded product was produced by the same method as in Example 1, except that hardwood pulp having an average fiber length of 0.9 mm was used instead of softwood pulp having an average fiber length of 2.3 mm.
  • Softwood pulp having an average fiber length of 2.3 mm was beaten until the Canadian Standard Freeness (CSF) became 400 mL, to thereby obtain pulp having an average fiber length of 1.8 mm.
  • a pulp molded product was produced by the same method as in Example 1, except that the above-described pulp having an average fiber length of 1.8 mm was used instead of softwood pulp having an average fiber length of 2.3 mm.
  • a slurry that contains pulp and water was prepared.
  • pulp bamboo pulp having an average fiber length of 1.6 mm was used.
  • the slurry was prepared such that the pulp content was 0.3% by mass.
  • a pulp molded product was produced by the above-described second method.
  • the dehydration step was performed such that the water content of the pulp layer immediately after dehydration became 65% by mass.
  • the hot pressing step was performed under the conditions of a heating temperature of 150°C, a press pressure of 0.5 MPa, and a press time of 180 seconds.
  • a pulp molded product was produced by the same method as in Example 1, except that softwood pulp having an average fiber length of 3.0 mm was used instead of softwood pulp having an average fiber length of 2.3 mm.
  • a pulp molded product was produced in the same method as in Example 1, except that the press pressure was set to 0 MPa instead of 0.5 MPa.
  • a picture was printed, by a silk-screen printing method, on the outer surface of each of the pulp molded products produced in Examples 1 to 5 and Comparative Examples 1 and 2.
  • the printed picture was visually observed to check the presence or absence of chipping in the picture and the presence or absence of rubbing in the picture.
  • An evaluation "A+” was assigned when neither chipping nor rubbing occurred in the picture.
  • An evaluation "A” was assigned when chipping did not occur in the picture, but rubbing did occur.
  • An evaluation "B” was assigned when chipping occurred in the picture. The result is described in the following table.
  • the arithmetic average roughness Ra was able to be reduced by pressing the pulp layer during drying. Also, as apparent from a comparison between Examples 1 to 5 and Comparative Example 1, the arithmetic average roughness Ra decreased when the average fiber length was shortened. Further, when pulp having an average fiber length of less than 3.0 ⁇ m was used in the first method, chipping did not occur in the picture, and practically sufficient printability was achieved. In particular, when pulp having an average fiber length of 1.7 ⁇ m or less was used in the first method, neither chipping nor rubbing occurred in the picture, and significantly excellent printability was achieved. Furthermore, as apparent from a comparison between Example 1 and Example 5, the standard deviation of basis weight was able to be reduced according to the first method, compared to according to the second method.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Containers Having Bodies Formed In One Piece (AREA)
EP21910707.5A 2020-12-25 2021-12-20 Article façonné moulé en pâte fibreuse et son procédé de fabrication Pending EP4269691A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020216814 2020-12-25
PCT/JP2021/047034 WO2022138563A1 (fr) 2020-12-25 2021-12-20 Article façonné moulé en pâte fibreuse et son procédé de fabrication

Publications (1)

Publication Number Publication Date
EP4269691A1 true EP4269691A1 (fr) 2023-11-01

Family

ID=82157970

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21910707.5A Pending EP4269691A1 (fr) 2020-12-25 2021-12-20 Article façonné moulé en pâte fibreuse et son procédé de fabrication

Country Status (5)

Country Link
US (1) US20230331425A1 (fr)
EP (1) EP4269691A1 (fr)
JP (1) JPWO2022138563A1 (fr)
CN (1) CN116601082A (fr)
WO (1) WO2022138563A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE543321C2 (en) * 2019-01-03 2020-11-24 Celwise Ab A pick-up press device and method of producing a 3D-molded product from a pulp slurry
JP2024002639A (ja) * 2022-06-24 2024-01-11 Ｔｏｐｐａｎホールディングス株式会社 パルプモールド成形品

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08158299A (ja) * 1994-12-01 1996-06-18 Honshu Paper Co Ltd モールディング成形体
EP1126083B1 (fr) * 1998-05-07 2010-03-10 Kao Corporation Corps moule
JP3126714B2 (ja) * 1998-12-28 2001-01-22 花王株式会社 パルプモールド成形体
JP2001123400A (ja) * 1999-10-22 2001-05-08 Oji Packaging Systems Co Ltd パルプモールドの製造方法
JP2002102109A (ja) * 2000-09-28 2002-04-09 Kao Corp 使い捨て排泄用容器
JP2002105898A (ja) * 2000-09-29 2002-04-10 Kao Corp 抄造成形体
JP3970173B2 (ja) * 2002-12-02 2007-09-05 花王株式会社 パルプモールド成形体の製造方法
JP3970272B2 (ja) * 2004-09-10 2007-09-05 花王株式会社 繊維成形体製造用の乾燥型

Also Published As

Publication number Publication date
US20230331425A1 (en) 2023-10-19
CN116601082A (zh) 2023-08-15
WO2022138563A1 (fr) 2022-06-30
JPWO2022138563A1 (fr) 2022-06-30

Similar Documents

Publication Publication Date Title
US20230331425A1 (en) Pulp molded product and method of producing the same
FI127679B (en) Thermoplastic fibrous materials and the process for their manufacture
UA124525C2 (uk) Фасонна підкладка або тарілка з волокнистого матеріалу і спосіб її виготовлення
EP4382669A1 (fr) Article moulé en pâte et son procédé de production
RU2710175C2 (ru) Легкий формованный продукт большого размера и способ его изготовления
WO2023145458A1 (fr) Produit moulé à base de pâte à papier
SE1650262A1 (en) Method of manufacturing 3d shaped articles comprising nanofibrillated polysaccharide from cellulose
WO2023248786A1 (fr) Produit moulé de pâte à papier
EP4382668A1 (fr) Produit de pâte de cellulose moulée et son procédé de fabrication
JP7248175B2 (ja) パルプモールド成形品及びその製造方法
WO2023248833A1 (fr) Article moulé dans un moule à pâte
WO2023145541A1 (fr) Produit moulé de pâte à papier
WO2023145457A1 (fr) Produit moulé de moule de pâte à papier
JP7248176B2 (ja) パルプモールド成形品及びその製造方法
US1663504A (en) Press-dried structural insulating board and process of making same
CN117716089A (zh) 纸浆模塑成形品及其制造方法
JP2024038851A (ja) パルプモールド成形品及びエンボス加工済みパルプモールド成形品
WO2024225063A1 (fr) Article moulé par moulage de pâte à papier et son procédé de fabrication
KR102151370B1 (ko) 다기능성 섬유 구조체의 제조방법 및 이에 의해 제조된 섬유 구조체
CN117716088A (zh) 纸浆模塑成形品及其制造方法
JP2024090057A (ja) パルプモールド成形品及びその製造方法
JP2024159117A (ja) パルプモールド成形品及びその製造方法
KR20160117768A (ko) 입체형상의 무늬목 성형물 제조방법

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20230411

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)