JP2006327633A - Paper molded article and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper molded article which not only facilitates molding operation at an advantageous manufacturing cost but also poses no problem in strength and can hardly be crushed by forming creases at least on the side face part of the molded paper molded article when the paper molded article consisting of a integral molding of the upper face part, the side face part and the bottom face part, and to provide its manufacturing method. <P>SOLUTION: The paper molded article 1 manufactured by pressing a paper base material made by stacking a plurality of thin sheets of paper one face of which is coated with an adhesive and integrally molding the upper face part 2, the side face part 3 and the bottom face part 4, is characterized by preparing a number of reinforcing parts 5 by mutually heat welding the creases formed on at least side face part 3 by a heat press or a high-frequency press. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper molded product that exerts a reinforcing function by closely contacting the collars to each other, and a method for manufacturing the same.

  Conventionally, various paper molded products have been frequently used for the purpose of disposable. These paper molded products include, for example, paper containers and paper tableware. However, since paper alone is insufficient in rigidity or strength, it is press-molded using cardboard having a plastic layer on the surface, or a paper base. The material is impregnated with a thermosetting resin and cured by hot pressing. However, since the resin used to reinforce the paper molded product is not decomposed by microorganisms in the soil when discarded, it is not preferable from the viewpoint of environmental protection. Only.

  In the case of forming a paper container having a cylindrical body and a disk-shaped bottom plate, the one in Patent Document 1 is composed of an inner layer material and an outer layer material, and both ends are curled to provide strength. Is provided.

In the case of Patent Document 2, when a paper container is formed by deep drawing, the paper base material may be broken at the time of molding. In order to prevent this, while holding the paper base material that becomes the flange portion of the container, The first press work is performed. After that, the second press working is performed to squeeze deeper while crushing the wrinkles generated in the flange portion.
Japanese Patent Laying-Open No. 2005-35593 (Summary, see FIG. 1) Japanese Unexamined Patent Publication No. 2003-160119 (Summary, see FIG. 1)

  However, as in Patent Document 1, if the cylindrical body is composed of an inner layer material and an outer layer material, and both ends are curled to give strength, not only the molding becomes troublesome, but also in terms of manufacturing cost. Is also disadvantageous.

  Further, as in Patent Document 2, when the deep drawing press processing is performed in the first stage and the second stage, the molding operation becomes troublesome and disadvantageous in terms of manufacturing cost. There is also a problem that the side surface of the container is weak in strength and easily crushed.

  Further, the above-described paper container, paper tableware, and the like are shaped so as not to have wrinkles with an emphasis on the appearance, but some paper molded products may have wrinkles. For example, garden articles to be buried in the soil, packing cushioning materials stored in cardboard boxes, etc., regardless of the form of the appearance, these paper molded products have some degree of wrinkles. There is no problem.

  The present invention has been made in order to solve the problems associated with the above-described conventional technology, and when forming a paper molded product in which the upper surface portion, the side surface portion, and the bottom surface portion are integrally formed, the forming operation is easy and the manufacturing is performed. An object of the present invention is to provide a paper molded product and a method for producing the same, which are not only advantageous in terms of cost, but also are not easily crushed by forming a ridge on at least a side surface of the molded paper molded product. And

  In order to achieve the above object, the invention according to claim 1 presses a paper base material in which a plurality of thin papers coated with an adhesive on one side is laminated, and integrally forms a top surface portion, a side surface portion and a bottom surface portion. The paper molded product is characterized in that at least the ridges formed on the side surface portions are heat-sealed to each other by a hot press or a high frequency press to form a large number of reinforcing portions.

  The invention according to claim 3 for achieving the above object is characterized in that a paper base material in which a plurality of thin papers are laminated is disposed between a pair of male and female molds, and the molds are relatively In the manufacturing method of a paper molded product in which the paper base material is pressure-molded by being moved close to and away from the outer periphery, the paper base material is composed of a plurality of thin papers coated with an adhesive on one surface, and the outer periphery of the male convex portion A gap several times the thickness of the paper base is provided between the surface and the inner surface of the concave portion of the female mold, the paper base is disposed between the molding dies, and the paper base is heated by the heated molding dies. The material is hot-pressed or high-frequency pressed, and a plurality of reinforcing portions are formed by heat-sealing the ridges formed on the paper base material between the outer surface of the male convex portion and the inner surface of the female concave portion. A method for producing a paper molded product.

  The present invention according to claim 1 presses a paper base material in which a plurality of thin papers coated with an adhesive on one side is pressed to form a paper molded product in which an upper surface portion, a side surface portion and a bottom surface portion are integrally molded. In this case, since a large number of ridges are formed at least on the side surface portions, and these ridges are heat-sealed to each other to form a large number of reinforcement portions, the side surface portion of the paper molded product itself is reinforced by the reinforcement portions. It becomes a paper molded product that is not easily crushed against pressure from the direction and has no problem in strength. In addition, since a paper molded product can be formed by simple drawing without requiring relatively high accuracy, it is easy to mold and is extremely advantageous in terms of cost. In addition, if a reinforcing portion is formed on the upper surface portion such as a flange portion, a paper molded product having further strength can be obtained.

  According to a third aspect of the present invention, a paper base is formed of a plurality of thin papers coated with an adhesive on one side, and a paper base is provided between the outer surface of the male convex portion and the inner surface of the female concave portion. Since the paper substrate is hot-pressed or high-frequency pressed with a gap several times the thickness of the material, it is easy to form wrinkles on at least the side surface of the paper molded product, and this is thermally fused to each other. The reinforcing part can be formed smoothly. In particular, since the press is not a multi-stage press, the manufacturing process is greatly simplified and the manufacturing cost is advantageous. Even when forming many types of paper molded products, the gap between the female mold and the male mold is large, so there is no need to change the setup frequently, and this is also advantageous in terms of cost. .

  Embodiments of the present invention will be described below with reference to the drawings.

  1 is a perspective view showing a paper molded product according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a paper substrate used for molding the paper molded product. FIGS. 4A, 4B, and 4C are schematic cross-sectional views showing stepwise a manufacturing method for forming the paper molded product.

  First, as shown in FIGS. 1 and 2, the paper molded product 1 according to the present embodiment includes an upper surface portion 2 including a flat portion such as a flange portion, a cylindrical side surface portion 3, and a flat bottom surface portion 4. And these are integrally formed by a paper base made of laminated thin paper.

  The upper surface portion 2 and the side surface portion 3 are formed with a reinforcing portion 5, for example, when the paper molded product 1 is lifted, or when the upper surface portion 2 is prevented from being deformed or an article is stored inside. Further, deformation such as bulging of the side surface portion 3 can be prevented.

  In particular, the reinforcing portion 5 of the present embodiment forms a large number of wrinkles with the paper base material 10 itself, which is a material used, when the paper molded product 1 is formed, and heat-bonds these wrinkles to each other. Forming. As the paper base material 10, as shown in FIG. 3, a laminate of a plurality of thin papers 11 each having an adhesive S applied on one side is used. If such a paper base material 10 is used, when it arrange | positions between a pair of metal mold | dies and shape | molds by adding an aperture | diaphragm | restriction, each thin paper 11 itself will have a vertical gutter, or the several thin paper 11 whole laminated | stacked Therefore, when these are heat-sealed to each other, it is possible to form the reinforcing portion 5 having extremely high strength against the applied pressure from the vertical direction.

  The molding of the paper molded product 1 will be further described in detail. The paper base 10 of the present embodiment uses a thin paper 11 having a predetermined width coated with an adhesive S on one side. The paper base 10 is drawn from a roll wound and a drawn die having a predetermined shape is drawn out. What was punched out using may be used, and what was cut into a predetermined length may be used directly.

  Here, as the thin paper 11, for example, when a container or a cushioning material for packing is formed, a kraft paper having a thickness t of about 0.05 mm to 0.2 mm can be used. Adhesive S is applied in advance and dried in an environment of normal temperature, normal pressure and humidity. When dried in such an environment, the moisture content of each thin paper 11 becomes about 7%, and when the heat press or the high frequency press is performed later, the mutual heat fusion can be ensured. The molded product can be taken out from the inside, which is extremely advantageous in terms of workability and manufacturing cost.

  Further, as the adhesive S, an adhesive such as water-soluble, thermosetting, and hot melt can be used, but it is preferable to use a water-soluble adhesive that is easily decomposed by soil microorganisms.

  In the present embodiment, as shown in FIG. 4A, the paper base 10 is prepared by preparing a plurality of thin papers 11 wound in a roll shape, and is drawn out from the rolls R1, R2, R3. 11 is a disk having a predetermined diameter D punched by a punching die (not shown).

  As shown in FIG. 4 (B), it is preferable to supply the disk-shaped thin paper 11 onto a female mold 22 which will be described later as a paper base material 10 formed by stacking a plurality of sheets on the same surface while punching.

  Note that the paper base 10 may be obtained by directly laminating the thin paper 11 drawn from the rolls R1, R2, and R3 into a predetermined length on the same surface on the female mold 22, and after being aligned once It may be set on the female mold 22. In any case, the laminated paper bases 10 are preferably arranged so that the lowermost one has the adhesive S side as the upper surface and the uppermost one has the adhesive S side as the lower surface.

  As shown in FIGS. 4B and 4C, the molding die 20 in this embodiment corresponds to the male die 21 that is tapered to some extent so as to be tapered toward the tip, and the male die 21. And a female die 22 having a shape expanded upward. In particular, the molding die 20 of the present embodiment has the male die 21 and the female die 22 aligned between the outer peripheral surface 21b of the convex portion 21a of the male die 21 and the inner side surface 22b of the concave portion 22a of the female die 22. In this case, the gaps G are separated so that a gap G several times the thickness T of the paper substrate 10 is generated.

  Such a configuration of the mold 20 can improve the releasability after molding and facilitate the formation of wrinkles. That is, when the male mold 21 and the female mold 22 are close to each other, and there is a gap G between the side surfaces of the two, the paper base 10 here can easily form a large number of wrinkles extending in the vertical direction, When the convex part 21 of the male mold 21 is fitted into the concave part 22 a of the female mold 22, a large number of ridges are crushed and the overlapping parts are heat-sealed to form the reinforcing part 5 on the side part 3. Will be.

  More specifically, it has been found by experiments that the gap G is preferably about 4 mm to 10 mm when the thickness t of the thin paper 11 is 0.05 mm to 0.2 mm.

  However, the space between the front end surface 21c of the convex portion 21a of the male mold 21 and the bottom surface 22c of the concave portion 22a of the female mold 22 is set to be smaller than the thickness T of the paper base 10, and the bottom surface portion 4 of the paper molded product 1 As for the part which becomes, it is trying to form the exact plane which a wrinkle does not produce. If it does in this way, in the case of a container, a bottom will become flat and installation stability will be secured.

  Moreover, as the shaping | molding die 20, the heating means 23 and 24 are provided in the inside, for example, and it is heated by about 180 to 200 degreeC. If such a hot press mold 20 is used, the adhesive S of the laminated paper base material 10 expels the water contained in the paper base material 10, thereby softening the adhesive S. Since bonding is performed, the time required for bonding is extremely short, and the molded product can be immediately taken out from the mold, thereby improving workability. In addition, as a material of the shaping | molding die 20, it is preferable to use an aluminum alloy etc.

  Next, the operation will be described.

  First, the thin paper 11 drawn from each of the rolls R1, R2, R3 and coated with the adhesive S on one side is punched into a disk shape having a predetermined diameter D by a punching die, and then supplied onto the female die 22. The paper substrate 10 in a stacked state is used. As shown in FIG. 3, the paper substrates 10 are arranged so that the lowest adhesive S side is on the upper side and the uppermost adhesive S side is on the lower side.

  When the male mold 21 is lowered, the paper base 10 is gradually pushed into the female mold 22, but the male mold 21 is tapered toward the tip, and the female mold 22 is expanded upward. Since it has a shape, the paper base 10 is taken in from the upper surface portion of the female die 22 having a wide opening and is squeezed toward the tip of the relatively small male die 21, and is pushed in while a large amount of wrinkles are formed. It is. In particular, in the present embodiment, the gap G between the outer peripheral surface 21b of the convex portion 21a of the male mold 21 and the inner side surface 22b of the concave portion 22a of the female mold 22 is large. Can be easily formed.

  Further, when the male mold 21 is lowered, a large amount of wrinkles are gradually crushed between the outer peripheral surface 21b of the convex portion 21a of the male mold 21 and the inner side surface 22b of the concave portion 22a of the female mold 22 and overlap each other. become.

  And when the convex part 21a of the male mold | type 21 fits into the recessed part 22a of the female mold | type 22, many mutually overlapping wrinkles will be crushed completely, and each thin paper will be by heat of the male mold | type 21 and the female mold | type 22 of a heating state. The moisture contained in 11 is expelled, whereby the adhesive S is softened, and the ridges are heat-sealed. This state is also performed between the base surface 21 d of the male mold 21 and the upper surface 22 d of the female mold 22. In addition, the paper base 10 is not wrinkled between the tip surface 21c of the convex portion 21a of the male mold 21 and the bottom surface 22c of the concave portion 22a of the female mold 22, and a flat plane is formed. In addition, when the water content of the paper substrate 10 is insufficient, water may be replenished by spraying or the like.

  As a result, between the male mold 21 and the female mold 22, a paper molded product 1 having an upper surface portion 2 formed of a flange portion, a cylindrical side surface portion 3, and a flat bottom surface portion 4 is formed. However, the upper surface portion 2 and the side surface portion 3 are formed with the reinforcing portions 5.

Since the paper molded product 1 formed in this way is solidified within a very short time, it can be taken out immediately after the male mold 21 is separated from the female mold 22.
<Experimental example>
Three sheets of kraft paper having a thickness t of 0.075 mm were used as the paper substrate 10, and vinyl acetate as the water-soluble adhesive S was applied to one side thereof. This was dried in an environment of normal temperature and normal pressure and humidity, and the water content of each thin paper 11 was set to about 7%.

  The paper base 10 is pressurized with a molding die 20 heated to 180 ° C., and has a size such that the top surface 2 has a diameter of 120 mm, a height of 100 mm, and the bottom surface 4 has an outer diameter of 90 mm as shown in FIG. The paper molded product 1 of a cup-shaped container having a cylindrical side surface portion 3 having a reinforcing portion 5 and a flat bottom surface portion 4 was formed.

  When the paper molded product 1 was pressed between the flat plate 30 and the pressure plate 31 as shown in FIG. 6, the compression value was 27 kgf (264.6 N).

  Using a similar material, a cup-shaped container 1a having the same size as the paper molded product 1 and without the reinforcing portion 5 is formed as shown in FIG. When tried, the compression value was 9 Kgf (88.2 N).

  As a result, it was found that the paper molded product 1 according to the present invention has a strength three times that of the paper molded product 1 without the reinforcing portion 5.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, the paper molded product 1 according to the above-described embodiment includes the upper surface portion 2 formed of the flange portion, the cylindrical side surface portion 3, and the flat bottom surface portion 4. For example, FIG. B) may be a packing cushioning material having a flat top surface portion 2, a side surface portion 3 recessed from the top surface portion 2, and a bottom surface portion 4, as well as a container and tableware. It may be a gardening article such as a bowl or a hat.

  Moreover, in embodiment mentioned above, although shape | molding by the hot press, you may heat-mold not only by this but by the high frequency press.

  The present invention can easily form a paper molded product such as a container having a reinforcing function or a cushioning material for packing.

It is a perspective view which shows the paper molded product which concerns on embodiment of this invention. It is sectional drawing which follows the 2-2 line of FIG. It is sectional drawing which shows the paper base material used in order to shape | mold the paper molded product. It is a schematic sectional drawing which shows the manufacturing method which shape | molds the paper molded product in steps. It is a schematic perspective view which shows this invention product and a conventional product. It is a schematic sectional drawing which shows the state of a pressurization experiment. (A) is a perspective view which shows the paper molded product which concerns on other embodiment of this invention, (B) is sectional drawing which follows the BB line of (A).

Explanation of symbols

1 ... paper moldings,
2 ... upper surface part,
3 ... Side part,
4 ... bottom part,
5 ... Reinforcing part,
10 ... paper substrate,
11 ... thin paper,
20 ... Mold,
21 ... Male type,
21a ... convex part,
21b ... outer peripheral surface,
22 ... Female type,
22a ... recess,
22b ... inside surface,
G: Gap S ... Adhesive.

Claims (6)

A paper base product obtained by pressing a paper base material obtained by laminating a plurality of thin papers coated with an adhesive on one side, and integrally forming an upper surface portion, a side surface portion, and a bottom surface portion,
A paper-molded article, wherein at least the ridges formed on the side surface portion are heat-sealed with each other by a hot press or a high-frequency press to form a large number of reinforcing portions. The paper molded product according to claim 1, wherein the adhesive is a water-soluble adhesive. Paper molding in which a paper base material in which a plurality of thin papers are laminated is disposed between a pair of male and female molds, and the paper base is pressure-molded by operating the molding die relatively close to and away from each other. In the manufacturing method of goods,
The paper base is composed of a plurality of thin papers coated with an adhesive on one side, and is several times the thickness of the paper base between the outer surface of the male convex portion and the inner surface of the female concave portion. The paper base is placed between the molds, the paper base is hot-pressed or high-frequency pressed with the heated mold, and the outer surface of the male convex part and the female concave part are pressed. A method for producing a paper molded product, characterized in that a plurality of reinforcing portions are formed by mutually heat-sealing ridges formed on the paper base material with an inner surface. The said thin paper is a manufacturing method of the paper molded article of Claim 3 which dried after applying an adhesive agent to one side under normal temperature normal pressure normal humidity conditions. The method for producing a paper molded product according to claim 3 or 4, wherein the adhesive is a water-soluble adhesive. 4. When the thickness of the thin paper is 0.05 mm to 0.2 mm, the gap between the inner surface of the female concave portion and the outer peripheral surface of the male convex portion is set to 4 mm to 10 mm. The manufacturing method of the paper molded product in any one of -5.

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