JP2007276234A - Molding made of composite material comprising paper and synthetic resin and its molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding made of a composite material comprising paper and a synthetic resin, a molding using a paper material, which keeps the rigidity of the paper material strengthened by a synthetic resin molding layer, enables molding having a minute deformed part, and is able to retain a shape during molding without being restored even when exposed to heat and vapor, and provide its molding method. <P>SOLUTION: In the molding 1, the synthetic resin molding layer 3 is integrated/molded with/on the surface of the paper material (stretchable/contractable paper 2) having elasticity. The paper material 2 is stretched/deformed according to the shape of the synthetic resin molding layer 3 in the molding 1. In its molding method, by injection-molding a molten resin 8 on the surface of the paper material having elasticity which is set in a mold, and by pressing/deforming the paper material 2 by packing the molten resin 8 in a cavity 10 in the mold, the synthetic resin molding layer 3 is formed integrally with the paper material 2 to form the molding 1 in a prescribed shape comprising the paper material 2 and the synthetic resin molding layer 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molded article made of a composite material of paper and synthetic resin and a molding method thereof.

  Conventionally, a technique for forming a container by drawing or press-molding paper has been developed. As an example, the deep-drawn paper tray forming method described in Patent Document 1 forms a deep-drawn paper tray having a flange portion using a blank in which a thermoplastic resin layer is laminated on at least one surface of paperboard. And a step of forming the flange portion of the deep-drawn paper tray on a smooth surface by ultrasonic processing.

  However, according to the above method, there is a disadvantage in that a step due to the forming flaw occurs in the flange portion formed on the paper tray. For this reason, Patent Document 1 requires a step of forming a step generated in the flange portion on a smooth surface by ultrasonic processing, but it has been difficult to obtain a perfect smooth surface.

  Furthermore, the technique of Patent Document 2 made to eliminate such inconvenience is a drawing of a blank sheet obtained by processing ruled lines on a blank sheet made of a laminated sheet material in which a thermoplastic resin layer is laminated on at least one side of a paper material. Then, a paper container having a flange portion with a sealing surface on the upper surface is formed, and then a tunnel-like hole in the flange portion of the sealing surface of the flange portion, which is formed by folding with a ruled line, is heated by press molding or press molding. Then, it is crushed flat.

  However, in both Patent Documents 1 and 2, since a large uneven step due to a forming flaw occurs in the flange portion during drawing, ultrasonic processing is performed as described above in order to reduce the uneven step of the flange portion as much as possible. In other words, smoothness is obtained by using a crease, or by making a ruled line on the flange portion in advance, or by laminating a thermoplastic resin on the surface of the flange portion having a step. However, in any case, since the sheet material in which the thermoplastic resin layer is laminated on one side of the paper material is drawn, it is inevitable that a forming flaw occurs during the drawing process.

In addition, in a molded product in which irregularities are formed by a conventional press process using only a single paper material, a molding wrinkle is generated in the deformed portion as described above, and a restoring force acts on the deformed portion. It was difficult to form irregularities. Furthermore, the paper material alone has poor rigidity, and when exposed to heat or steam, there is a disadvantage that deformation occurs in the restoring direction.
JP 2000-33927 A JP 2004-262484 A

  The present invention has been made in view of the above circumstances, and is a molded product using a paper material, which enhances the rigidity of the paper material by a synthetic resin molding layer and enables molding having a fine deformed portion. Another object of the present invention is to provide a molded article made of a composite material of paper and a synthetic resin, which can maintain the shape during molding without being restored even when exposed to heat or steam, and a molding method thereof.

  In order to achieve the above object, a molded article made of a composite material of paper and synthetic resin according to claim 1 of the present invention is formed by integrally molding a synthetic resin molding layer on the surface of a paper material having elasticity. A molded article, wherein the paper material is stretched and deformed in accordance with the shape of the synthetic resin molding layer in the molded article.

  According to a second aspect of the present invention, there is provided a molded article made of a composite material of paper and synthetic resin. In the first aspect, the stretchable paper material is expanded and contracted by forming the paper material into a wave shape. It has the property.

  According to a third aspect of the present invention, there is provided a method for molding a molded article made of a composite material of paper and synthetic resin, wherein a molten resin is injection-molded on the surface of a stretchable paper material inserted in a mold. Thus, the paper material is pressed and deformed by filling the cavity in the mold with the molten resin, so that a synthetic resin molding layer is integrally formed on the paper material, and the paper material and the synthetic resin molding are formed. A molded product having a predetermined shape composed of layers is formed.

  According to a fourth aspect of the present invention, there is provided a molding method of a molded article made of a composite material of paper and synthetic resin, according to the third aspect, wherein the paper material is loaded in the mold in a state where predetermined printing is performed. After entering, the mold is closed and the molten resin is injection-molded.

  Further, according to a fifth aspect of the present invention, there is provided a molding method of a molded article using a composite material of paper and synthetic resin, wherein the gold is pre-formed into an approximate form of the finished product in the third or fourth aspect. After the mold is inserted, the mold is closed and the molten resin is injection-molded.

  As described above, a molded article made of a composite material of paper and synthetic resin according to the present invention is a molded article in which a synthetic resin molding layer is integrally molded on the surface of a paper material having elasticity, The paper material is stretched and deformed according to the shape of the synthetic resin molding layer. The advantage of a molded article made of a composite material in which such a paper material and a synthetic resin molding layer are integrally combined can be easily and finely printed with ink or the like on the paper surface by using the paper material. In addition, while taking advantage of the properties of paper, the synthetic resin molding layer compensates for the fragile defects of the paper and reinforces rigidity to enable fine deformation.

  That is, in the case of a conventional synthetic resin molded product, it is difficult to print on the surface and it is difficult to express fine characters and designs, but the molded product according to the present invention has a paper material. Since this paper material is printed, it becomes easy to express fine characters and designs.

  In addition, unlike the conventional case where unevenness is formed by pressing using only a single paper material, the rigidity of the paper material can be reinforced by integral molding with a synthetic resin, and with the synthetic resin molding layer Due to the integral unity, it is possible to maintain the shape during molding without being deformed in the restoring direction even when exposed to heat or steam.

  In addition, since the stretchable paper material is stretched and deformed according to the shape of the synthetic resin molding layer in the molded product to form deformed portions such as irregularities, the stretchable paper material is finely deformed by the pressing force of the molten resin. At the same time, the paper material maintains the shape at the time of molding following the fixed shape after cooling of the molten resin. Furthermore, when the molten resin adheres to and merges with the fibers of the paper material and the expansion and contraction shape of the paper material, both are firmly and integrally combined without using an adhesive.

  Furthermore, the thickness of the synthetic resin molding layer can be adjusted by the shape of the cavitation by the method of injection molding a molten resin on the surface of the paper material having elasticity.

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

  1 (a) and 1 (b) show a molded article according to the present invention, and FIG. 1 (a) is a plan view of a dish-like container having a letter “A” printed on the upper surface as an example. 1 (b) is a cross-sectional view taken along line AA in FIG. 1 (a). As shown in FIG. 1 (b), the molded product 1 of this example is composed of a stretchable paper (hereinafter referred to as "stretchable paper") 2 and a synthetic resin molding layer 3 that are integrally combined. It is formed in a predetermined container shape. Further, the molded product 1 has a shape in which a protruding portion 4 corresponding to the letter “A” is formed in the center plane, and an arc-shaped protruding portion 5 is formed in the peripheral portion.

  A method for forming such a molded product will be described with reference to FIGS. FIG. 2A shows a state in which the mold of the injection mold is opened. The fixed mold 6 is illustrated on the left side, and the movable mold 7 is illustrated on the right side. The fixed mold 6 and the movable mold 7 are formed with molding surfaces 6a and 7a for forming the molded product 1 shown in FIGS. 1 (a) and 1 (b).

  Further, the movable die 7 is formed with a gate 9 which is an injection port of the molten resin 8 and has a direct gate type configuration in which the gate 9 directly faces the cavity 10. The mold illustrated in this way shows a basic configuration as an example, and the gate configuration and other configurations can be changed using a well-known technique depending on the molded product to be manufactured.

  As a molding method using the above-mentioned mold, first, the stretchable paper 2 is mounted on the molding surface 6a of the fixed mold 6 with the mold opened as shown in FIG. As the stretchable paper 2, the stretchable paper 2 known as “WavyWavy” (registered trademark, Nippon Paper Industries Co., Ltd.) may be used. The stretchable paper 2 is formed by forming thin wavy irregularities on the front surface of a thin paper material, and deforms in a direction in which the wavy irregularities extend when pulled in the surface direction.

  In addition, since such stretchable paper 2 is easy to print with ink as in the case of ordinary paper, it is possible to print detailed characters and designs in advance by general printing such as offset and gravure before molding. It is possible to draw.

  Furthermore, the stretchable paper 2 used in the present embodiment is deformed following the pressing only by pressing in the direction perpendicular to the surface, so that pre-forming before molding is easy. Accordingly, the stretchable paper 2 may be attached to the injection mold in a state of being pre-formed into an approximate form of the finished product. Further, although the stretchable paper 2 shown in FIG. 2A is trimmed into a predetermined shape, the extra length around the molded paper can be easily cut.

  Next, as shown in FIG. 2B, the mold is closed and the molten resin 8 is injected from the gate 9 into the cavity 10. As the synthetic resin used as the molten resin 8, a known thermoplastic resin can be used. For example, other well-known thermoplastic resins such as polypropylene, polyethylene, polystyrene, ABS resin, AS resin, etc., selected according to the use of the molded product or required characteristics can be used.

  According to the above-described injection molding, the molten resin 8 stretches the stretchable paper 2 due to the injection pressure, and the meltable resin 8 goes well into the mold due to the stretchability of the paper, and the stretchable paper 2 follows the shape of the mold well. Thus, a deformed portion such as an accurate unevenness is formed. Further, by the method of injection molding the molten resin 8 on the surface of the stretchable paper 2 as described above, the thickness of the synthetic resin molding layer 3 can be adjusted by the shape of the cavitating.

  Furthermore, since the molten resin 8 adheres to the fibers and wavy irregularities of the elastic paper 2 at high temperature and high pressure in the cavity 10 by injection molding of the molten resin 8, the elastic paper 2 and the synthetic resin can be used without using an adhesive. The molding layer 3 is integrally and strongly united. Therefore, when this molded product is used as a container for heated food, there is no paste odor due to heating of a microwave oven or the like, the adhesive does not melt, and hygienic use is possible.

  Further, as shown in FIG. 2C, after the mold is cooled, the mold can be opened to obtain a molded product. The extra length 1a on the outer periphery of the molded product 1 is cut off by cutting, so that a molded product with a beautiful shape can be obtained.

  In the molded product according to the present invention, which of the stretchable paper and the synthetic resin molded layer is the content side should be determined according to the use of the molded product. In the case of food-related contents, the contents are usually stored on the synthetic resin side.

  Furthermore, the molded product according to the present invention can be used for various applications in addition to food containers. For example, when the molded product according to the present invention is formed as a CD case, it is possible to cleanly form the undercut of the locking projection that removably fits the center hole of the CD.

  The molded article by the composite material of the paper and the synthetic resin of the present invention and the molding method thereof prevent the molding wrinkles and the restoring action after molding as when the single piece of the paper material is press-molded, and the synthetic resin molded article As a molded product that can overcome the difficulties in printing, it is suitable for molded products such as containers and CD cases that are integrally molded with paper and synthetic resin, and has fine characters and prints. Paper that is capable of forming fine deformed parts and can maintain the shape during molding without being restored even when exposed to heat or steam, and the rigidity of the paper material can be reinforced by reinforcing the synthetic resin molding layer It can be used as a molded product made of a composite material of and a synthetic resin and a molding method thereof.

(a) is a top view of the molded article by the composite material of the paper and synthetic resin by this invention, (b) is the sectional view on the AA line of Fig.1 (a). (a)-(c) is sectional drawing, such as a metal mold | die for demonstrating the method to manufacture the molded article by the composite material of the paper and synthetic resin by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molded product 1a Extra length part 2 Paper material which has elasticity (elastic paper)
DESCRIPTION OF SYMBOLS 3 Synthetic resin molding layer 4 Projection part 5 Arc-shaped projection part 6 Fixed metal mold | die 7 Movable metal mold | die 6a, 7a Molding surface 8 Molten resin 9 Gate 10 Cavity

Claims (5)

A molded product in which a synthetic resin molding layer is integrally formed on the surface of a paper material having elasticity, wherein the paper material is stretched and deformed according to the shape of the synthetic resin molding layer in the molded product. Molded product made of composite material of paper and synthetic resin. 2. The molded article made of a composite material of paper and synthetic resin according to claim 1, wherein the paper material having elasticity has elasticity due to the paper material being formed in a wave shape. By injection-molding a molten resin on the surface of the stretchable paper material charged in the mold, the paper material is pressed and deformed by filling the cavity in the mold with the molten resin, A composite of paper and synthetic resin, wherein a synthetic resin molding layer is integrally formed on the paper material to form a molded product having a predetermined shape comprising the paper material and the synthetic resin molding layer. Molding method of molded products with materials. 4. The paper and the composition according to claim 3, wherein after the sheet material has been subjected to predetermined printing and inserted into the mold, the mold is closed and a molten resin is injection-molded. Molding method of molded product by composite material with resin. 5. The molten resin is injection-molded by closing the mold after the paper material is pre-formed into an approximate shape of a finished product and then inserted into the mold. A method for forming a molded article using a composite material of paper and a synthetic resin as described.