JP2000309322A - Water-resistant pulp mold container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a mold container of particularly superior water resistance and sealing properties to be applied to various fields such as a liquid storage container, an instant noodle container and others. SOLUTION: A mold container is provided with a synthetic resin film layer 12 laminated on an inner face of a pulp mold product 11 and either a synthetic resin film layer 13 or a waterproof layer coated with a waterproof coating material formed on an outer face. A binder layer can be formed between the synthetic resin film layer and a pulp mold layer. Both of the inner and outer faces of the pulp mold container are provided with water-resistant layers, and the pulp mold container is provided with superior water resistance and sealing properties and used suitably as a liquid storage container, an instant noodle container and others.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulp mold molded product produced mainly by a wet method using pulp or the like as a raw material, and more particularly to a pulp mold container having particularly excellent water resistance.

[0002]

2. Description of the Related Art Conventionally, pulp molded products have been used for home appliances,
Although it is used for precision equipment and food packaging, it has recently been used as an alternative to plastic products and Styrofoam because of its environmental impact, especially because of its lower environmental impact, especially in terms of disposability. It has been used in many fields. In order to continuously manufacture pulp mold containers, a rotary table system and a linear intermittent system are known as drive systems of a molding machine. The apparatus for manufacturing a mold container by a rotating table system has, for example, a papermaking and molding mechanism and a mold clamping and drying operation mechanism. The papermaking and molding mechanism has a pulp slurry suction portion and a predetermined mesh type (papermaking type). It consists of a part that is dehydrated after being taken out. The water-containing molded body after dehydration is taken out while sucking using a mold corresponding to the shape of the molded body, and moved to a heat-drying mold to obtain a product.
In addition, in the straight intermittent method, after preheating the upper and lower surfaces of the pulp sheet, the pulp sheet is sent to a line-type continuous vacuum forming machine having a plurality of female dies and plugs to form a continuous container connected at the opening edge, and this is punched out with a punching die. To obtain a number of mold containers.

[0003]

However, the molded pulp molded article has been lacking in water resistance and sealing properties due to its characteristics, and thus can be used only for limited applications. For this reason, a certain degree of water resistance can be imparted by adding a water-proofing agent or the like to the pulp raw material, but the effect is extremely weak, and it has been unexpected to store a liquid. Further, a thermoplastic resin film is laminated on the inner surface of the pulp mold container by a vacuum forming method (Japanese Patent Application Laid-Open No. 51-137571), or a plastic sheet is laminated on the inner surface of the container by a vacuum forming method or a vacuum pressure method (Japanese Patent Laid-Open No. No. 10-218235), it is also known to impart water resistance, but a sufficient effect was not obtained. An object of the present invention is to provide a pulp mold container which is applicable to various fields such as a liquid storage container and an instant noodle container and has particularly excellent water resistance and hermeticity.

[0004]

The present invention has the following arrangement to solve the above-mentioned problems. That is, the first of the present invention, a synthetic resin film layer is laminated on one side of a pulp molded article, and a synthetic resin film is laminated on the other side,
Or a waterproof pulp mold container characterized by having a waterproof layer formed by applying a waterproof paint.
The second aspect of the present invention is the water-resistant pulp mold container described in the preceding item, which has an adhesive layer between the synthetic resin film layer and the pulp mold layer. A third aspect of the present invention is the water-resistant article according to the preceding claim, wherein a synthetic resin film layer is laminated on both sides of the pulp molded article, and the synthetic resin film layer on any one side of the container has micropores. Pulp mold container. Furthermore, a fourth aspect of the present invention is the water-resistant pulp mold container described in the preceding item, wherein the pulp molded article contains a water-resistant chemical.

[0005]

Embodiments of the present invention will be described in detail below. FIG. 1 is a partially cutaway front view showing an example of the pulp mold container of the present invention. FIG. 1 is a cross-sectional view showing an example of the container of the present invention. A synthetic resin is formed on one surface of a pulp molded article 11 formed from a raw material slurry of a pulp material such as waste paper pulp or virgin pulp by means such as vacuum forming or pressure forming. The water-resistant pulp mold container 10 has a waterproof layer formed by laminating a film layer 12, laminating a synthetic resin film layer 13 on the other surface, or applying a waterproof paint. Note that fine holes for ventilation may be provided in the synthetic resin film layer on the inner surface or the outer surface. FIG. 2 is a partially cutaway front view showing a modification of FIG. 1 and exaggerating the thickness direction, and shows an adhesive layer 15 between the synthetic resin film layer 13 on the outer surface and the surface of the pulp molded article 11. Is interposed.

[0006] The raw material of the pulp molded article is not particularly limited, and wastepaper pulp, virgin pulp, or a mixture thereof as appropriate may be used. When used for food containers such as instant noodle containers, it is desirable to use virgin pulp from the viewpoint of hygiene. As the synthetic resin film to be used, a thermoplastic resin film is used, and a single sheet such as a polyolefin such as polyethylene (PE) or polypropylene (PP), a polyester such as polyethylene terephthalate (PET), or a laminate of a plurality of these sheets The sheet can be optionally used according to its purpose. In particular, when it is desired to impart gas barrier properties to the container, a laminated sheet or the like in which a gas barrier layer such as an ethylene-vinyl alcohol copolymer (EVOH) is provided in the intermediate layer of the film can be used.

As the waterproof coating, waxes such as microcrystalline wax and paraffin wax, latexes such as polyvinylidene chloride-based latex, and acrylic emulsions can be arbitrarily used. In addition, as these coating methods, a spray method, a transfer method and the like can be used. In the case where the synthetic resin film layer is provided only on one side of the molded product, the synthetic resin film layer is provided on the side of the container to be used which requires more water resistance. For example, when used as a container for storing a liquid or the like, a film layer is provided inside the container.

In laminating a synthetic resin film on the surface of a pulp molded article, an adhesive such as vinyl acetate is applied to the surface of the film or the molded article in advance in order to adhere the two more tightly. For example, it is possible to provide an adhesive layer between the molded article and the film layer.

When a synthetic resin film layer is provided on both sides of a pulp molded article, it is more desirable that the film on one side of the container is provided with fine holes in view of production efficiency. In the present invention, since the synthetic resin film layer is provided by vacuum or air pressure molding, it is desirable that the container body has good air permeability, and the pulp mold molded article originally has air permeability due to its properties. This is because the resin film does not have air permeability, and thus, when film layers are provided on both surfaces, it is preferable that at least one surface has fine pores in advance. The upper limit of the diameter of the micropore is about 0.5 mm, and if it is more than that, irregularities are conspicuous on the surface when vacuum forming is performed. Note that which side of the film is provided with the micropores is arbitrarily determined according to the use of the container to be used, and the design and manufacturing process procedures. For example, when the present invention is used as a container for storing a liquid or the like. Will be provided with fine holes in the film outside the container.

[0010] In addition, pulp mold molded products may be used as water-resistant agents (water-proofing agents) such as sulfate bands, rosin-based internal sizing agents, petroleum resin-based sizing agents, glue, starch, CMC, PMC
VA, sizing agent such as alkyl ketene dimer, fluorine resin, polyamide resin, water repellent such as wax emulsion, urea-formaldehyde resin, melamine-
It is more desirable to add a latex such as a formaldehyde resin, dialdehyde starch, or SBR to the raw material slurry to enhance the water resistance of the mold container.

FIG. 3 shows an example of a method for producing the container of the present invention, in which (a) is a cross-section showing a step of laminating a synthetic resin film on the outer surface of a cup-shaped pulp molded product.
(B) is a sectional view showing a step of laminating a synthetic resin film on the inner surface. To laminate the synthetic resin film 13 on the outer surface, the mold 16 is placed on the male mold 16 while the synthetic resin film 12 is arranged above the male mold 16 and preheated. The film 12 is brought close to the outer surface of the molded product 11 and, at the same time, the layer of the molded product is evacuated. The resin film 13 is sucked from the male mold while being in close contact with the upper part of the mold container. Since the male mold 16 has a plurality of suction holes 17 and 17 and communicates with the suction port 18 as shown in the drawing, the outer surface of the molded molded product 11 is in a vacuum state, and the film 13 is drawn by the generated suction force. The layers are stacked as indicated by the dotted line 3a. Next, the container in which the synthetic resin film 13 is laminated on the outer surface is set in the female mold 19, and the preheated synthetic resin film 12 for the inner surface is suctioned from the female mold 19 in a state of being closely attached to the upper part of the mold container. The film 12 is pulled by the suction force generated through itself as shown in FIG.
As shown by the dotted line in FIG. Thereafter, the material is punched out by a punching blade having an outer peripheral shape of the container, and the inspection product is packed in an accumulation box.

The molded container 1 formed by the papermaking apparatus and the drying apparatus is subjected to a vacuum forming apparatus or a vacuum pressure forming apparatus 20.
After being inserted into the female mold (wooden mold, aluminum mold, etc.), it approaches a synthetic resin film preheated by an electric heater 4 or the like in advance. FIG. 4 shows a method of manufacturing the container of the present invention using a bowl-shaped pulp mold molded product. A bowl-shaped pulp mold molded product is inserted into a female mold 21, and a synthetic resin film 12 for an inner layer in the container is placed thereon. It is sectional drawing of the stage which performed. The film 12 is preheated by the hot plate 24. Female mold 21
Away from The female mold 21 is closed from the state of FIG. That is, the film 1 under the hot plate 24
The hot plate 24 is brought into close contact with the female mold 21 with the second plate 2 therebetween. Then
Each ventilation hole 25 of the holder 22, the bottom plate 23 and the hot plate 24,
The internal air pressure is exhausted through 26 and 27 (FIG. 5). While the internal air pressure is exhausted through the ventilation holes 25 and 26, the hot plate 2
Then, the synthetic resin film 12 is laminated by applying air pressure (pressure air vacuum forming) toward the inner surface of the container from the vent hole 27 of FIG. 4 (FIG. 6).
Next, after laminating the inner surface synthetic resin film 12, it is released and taken out. In this case, an extended side 31 is left around the flange (FIG. 7). 4 to 7, illustration of a suction hole formed in the female mold 21 is omitted.

The laminated product of the inner surface synthetic resin film obtained in FIG. 7 is inverted and inserted into the male mold 28, and the synthetic resin film 13 for the outer area layer is disposed thereon (FIG. 8). Male mold 28 of FIG.
Is closed, and the internal pressure is exhausted through the vents 25, 26, 27 (FIG. 9). Next, the internal air pressure is exhausted through the vents 26 and 27, and the synthetic resin film 13 is laminated by applying air pressure to the inside of the container from the vent 27 (FIG. 10). FIG.
After laminating the laminate, the synthetic resin film 1 is released on the inner and outer surfaces of the container.
An article obtained by stacking 2, 13 is taken out (FIG. 11). After that, the extended side 31 around the flange portion 30 is punched out, the shape is adjusted, and completed. 8 to 11, the illustration of the suction holes of the male mold 28 is omitted.

A molded pulp molded article 11 manufactured by an arbitrary method is fitted into a female mold 21 of a vacuum-pressure air molding apparatus 20 having a shape corresponding to the outer shape of the molded article, and is sucked into a hot plate 24 containing an electric heater or the like. The synthetic resin film 12 pre-heated and adhered by means is brought into close contact with the molded product 11, and air is sent from the hot plate side to pressurize the synthetic resin film 12 and, at the same time, through the air-permeable pulp molded product 11, By suctioning from the mold side, the film 12 is adhered to the container surface. Thereafter, a water-resistant paint is spray-coated on the outer surface of the container, dried, and if necessary, the outer peripheral flange portion 30 and the like are punched out to complete the shape.

When a synthetic resin film is laminated on both sides of the molded article, the synthetic resin film 12
After being bonded, the synthetic resin is further fitted into a male mold 21 of a vacuum-pressure air molding apparatus having a shape corresponding to the inner shape of the molded article, and closely adhered to a hot plate 24 containing an electric heater or the like by means of suction or the like to preheat the synthetic resin. Adhere the film to the mold container,
The film is adhered to the container surface by sending air from the hot plate side to press the synthetic resin film. In this case, the air permeability is poor because the film is already laminated on one side, so that the adhesion of the synthetic resin film to the container is mainly performed by pressurization, in which case the pressurized air is good to escape. Thus, it is necessary to consider the shape of the mold of the molding apparatus. Further, since the pulp molded product itself has a structure having many voids, it is possible to provide a portion where the film is not laminated on the flange portion 29 or the like, and to suction air therefrom. If the portion is cut off when the product is completed, a pulp mold container in which the entire container is film-laminated can be obtained.

When a synthetic resin film layer is provided on both surfaces of a molded product, it is more desirable to form micro holes in the sheet to be laminated first, in view of production efficiency. However, in this case, since fine holes of the film remain on the surface of the finished product, it is necessary to provide the film in a portion where there is no problem in appearance and performance. This hole can be covered with an adhesive label or the like (not shown). In addition, the mold for vacuum and pressure molding is
A dedicated mold may be used, but a mold for press-drying and molding a pulp molded article may be diverted. In this case, there is no need to make an extra mold, so that the present invention can be manufactured economically and in a short time.

[0017]

According to the present invention, it is possible to obtain a pulp mold container which is applicable to various fields such as a liquid storage container and an instant noodle container, and is particularly excellent in water resistance and sealing property.
Further, the pulp mold container has a water-resistant layer formed on both inner and outer surfaces and is excellent in water resistance and sealing properties, and thus is suitable for a liquid storage container, an instant noodle container and the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the pulp mold container of the present invention.

FIG. 2 is a partially cutaway front view of a modification of FIG.

FIG. 3 shows a method for producing the container shown in FIG. 1,
(A) is a cross-section showing a step of laminating a synthetic resin film on the outer surface of a cup-shaped pulp molded product, and (b) is a cross-sectional view showing a step of laminating a synthetic resin film on the inner surface.

FIG. 4 shows a method for producing a container of the present invention using a bowl-shaped pulp mold molded article, in which a bowl-shaped pulp mold molded article is inserted into a female mold, and a synthetic resin film for an area layer in the vessel is placed thereon. It is sectional drawing of a stage.

FIG. 5 is a cross-sectional view of a stage in which the female mold of FIG. 4 is closed and the internal pressure is discharged.

FIG. 6 is a cross-sectional view of a step of laminating a synthetic resin film on the inner surface of the container by pressurized vacuum forming.

FIG. 7 is a cross-sectional view of a state in which the mold is separated and taken out after lamination of FIG. 6;

FIG. 8 is a cross-sectional view of a stage where the inner surface synthetic resin film laminate obtained in FIG. 6 is inverted and inserted into a male mold, and a synthetic resin film for an outer area layer is disposed thereon.

FIG. 9 is a cross-sectional view of a stage in which the male mold of FIG. 8 is closed and the internal pressure is discharged.

FIG. 10 is a cross-sectional view of a step of laminating a synthetic resin film on the outer surface of the container by pressurized vacuum forming.

11 is a cross-sectional view of a state in which a product obtained by laminating the synthetic resin film on the inner and outer surfaces of the container after the lamination of FIG. 10 is taken out.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Pulp mold container 11 Pulp mold molded product 12, 13 Synthetic resin film layer 15 Adhesive layer 16, 28 Male type 17 Suction hole 18 Suction port 19, 21 Female type 20 Compressed air vacuum forming machine 22 Holder 23 Bottom plate 24 Hot plate 25, 26, 27 Vent 29 Recess 30 Flange 31 Extended side

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeo Oishi 5-12-8 Ginza, Chuo-ku, Tokyo Inside Oji Paper Co., Ltd. Packaging Development Promotion Department (72) Inventor Junichiro Kido 5--12 Ginza, Chuo-ku, Tokyo No. 8 Inside the Oji Paper Co., Ltd. Packaging Development Dept. F-term (reference) GB23 GB48 JB07 JB07A JD05D JK07 4L055 AG40 AG48 AG50 AG51 AG69 AG80 AG97 AH11 AH23 AH37 AJ02 BE08 BE14 BF07 BF08 BF09 FA19 GA04 GA05 GA30

Claims (4)

[Claims] 1. A pulp molded article having a waterproof layer formed by laminating a synthetic resin film layer on one side and laminating a synthetic resin film on the other side or applying a waterproof paint. Water-resistant pulp mold container. 2. The water-resistant pulp mold container according to claim 1, further comprising an adhesive layer between the synthetic resin film layer and the pulp mold layer. 3. The water-resistant material according to claim 1, wherein a synthetic resin film layer is laminated on both sides of the pulp molded article, and the synthetic resin film layer on one side of the container has micropores. Pulp mold container. 4. The water-resistant pulp mold container according to claim 1, wherein the molded pulp mold contains a water-resistant chemical.