JP4599636B2 - Pulp mold container manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulp mold container that uses a pulp material such as waste paper pulp, virgin pulp, and the like, and is formed by suction dehydration on a papermaking mold and heat drying in a press mold that fits, and a method for producing the same. .
[0002]
[Prior art]
Conventionally, pulp molds are mainly used for buffer containers such as egg containers, fruits and vegetables, and electrical products. These pulp molds are produced by using a waste paper pulp and performing suction suction dehydration on a paper mold in a wet manner, and removing a molding intermediate from the mold and drying it in a drying furnace. This method is widely used at a low cost, but its dimensional stability is inferior due to distortion at the time of drying and the cosmetics are also low. However, a pulp mold that uses virgin pulp and is formed by heat-drying in a press mold that fits after suction dehydration on a paper mold in a wet manner, because it has excellent dimensional stability and a smooth surface. It can also be used as a primary container.
[0003]
On the other hand, plastic molded containers are easy to mold, are cheaper than pulp molds, and have excellent water resistance and sealing properties. However, in recent years, environmental hormones (endocrine disrupting substances) have been reported to elute from some plastic containers. There is a concern about the safety of plastic containers. In terms of disposal, plastics are not decomposed even when they are landfilled, and volume reduction is required. During incineration, problems such as generation of hazardous substances such as dioxins and damage to incinerators were identified. The demand for plastic removal is increasing.
[0004]
Under these circumstances, paper, which is a natural material, has been reviewed. Paper materials are not only difficult to generate toxic substances even when incinerated, but can be recycled as recycled paper, and are biodegradable because they are natural materials. Recently, foamed polystyrene cushioning materials have become pulp mold cushioning materials, and foamed polystyrene instant noodle cups have shifted to paper materials such as paper cups.
[0005]
[Problems to be solved by the invention]
Pulp mold, which is also used for primary containers etc., is formed by heat drying in a press mold that fits after suction dehydration on wet paper making, and is a paper container formed by folding and bonding paperboard Compared with the advantage that there is a degree of freedom in shape, there is no bonding part, and the end face of the paper is not exposed, because it is molded directly from the pulp slurry into a three-dimensional shape, printing on the surface of the molded product The printing means such as letterpress printing with a rubber plate or resin plate, silk screen printing, and thermal transfer printing are limited, and fine color printing cannot be performed. In addition, it has disadvantages such as difficulty in laminating and coating a film on the surface of a molded product.
[0006]
Furthermore, in the case of a paper container molded from paperboard, the strength of the container can be easily controlled by controlling the paper thickness of the member. However, the pulp mold container is compatible with the suction balance on the paper making and the fitting. Since the thickness balance is determined by the accuracy of the press mold, even when it is desired to partially change the thickness of the container, it is necessary to correct an expensive mold.
[0007]
In view of such a background, the present invention is a pulp mold container that hardly generates harmful substances even by incineration, can be recycled as recycled paper, has biodegradability, and has a degree of freedom in shape. The present invention provides a pulp mold container that has cosmetic properties by fine color printing, can be manufactured as inexpensively as possible, and has a necessary function and strength, and a method for manufacturing the same.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the pulp mold container and the method for producing the same of the present invention are as follows.
The invention according to claim 1 is a step of forming a mold intermediate containing 70 to 96% of moisture by sucking and dewatering the pulp slurry onto the papermaking , and the pulp slurry on the papermaking on the surface of the mold intermediate. After dewatering by suction, press and dry with a press mold that fits in , and after placing a molded product that has been dried, press mold that is heated in the range of 150 to 200 ° C. with a press mold that fits together to form a pulp mold container. The manufacturing method of the pulp mold container characterized by comprising the process to form.
[0010]
The invention according to claim 2 includes a step of forming a mold intermediate containing 70 to 96% of moisture by sucking and dewatering pulp slurry onto the papermaking, and fitting after the pulp slurry is sucking and dewatering onto papermaking. After placing the pre-molded product that has been pressed and dried with a matching press die on the surface of the press die, the mold intermediate is overlaid on the surface of the pre-molded product, and a range of 150 to 200 ° C. by the press die that fits together. And a step of forming a pulp mold container by press-molding by heating .
[0021]
In particular, in a pulp mold container manufacturing method in which pulp slurry is sucked and dehydrated onto a papermaking mold and then pressed with a heated press mold that fits and dried, a sheet having a predetermined shape based on a substrate such as paper, Alternatively, when the molded product is placed on the surface of the mold intermediate sucked and dehydrated on the paper mold and then press-molded with a press mold that fits, the moisture of the mold intermediate sucked and dehydrated on the paper mold is: It penetrates into the sheet substrate of the predetermined shape, or the paper substrate which is the adhesive surface of the molded product, and the pulp fiber in the mold intermediate and the pulp fiber in the paper substrate are attracted by the surface tension of water, press, By drying, hydrogen bonds are generated between the two fibers, and sufficient adhesive strength can be obtained.
[0022]
Here, the sheet having a predetermined shape based on a base material such as paper is characterized in that the adhesive surface to the mold intermediate is paper, and therefore no adhesive is required. Further, the back surface of the adhesive surface may be a barrier layer such as a plastic film layer or a glass layer, or another layer, instead of paper or pulp mold. The adhesive action and the like will be described later.
[0023]
Furthermore, the predetermined shape means a shape that matches the shape of the desired part to which a sheet is to be added.If a cup-shaped inner surface side is desired, the inner shape of the inner surface of the container is changed to the bottom of the circular container. If it is desired, a circular shape is indicated, and if it is a container shoulder, it indicates a ring shape.
[0024]
The mold intermediate is a product obtained by sucking and dewatering pulp slurry onto a papermaking machine to make up the fiber, and refers to a state where the moisture content is 96 to 70%.
In addition, the pre-molded product refers to a pulp mold product that is pressed and dried with a press mold that fits after the pulp slurry is sucked and dehydrated onto the papermaking mold, and appropriately added, coated, impregnated, laminated, etc. Processing is added.
[0025]
In these pulp mold containers, there is almost no step at the joint. Although a joint groove that cannot be said to be a step may be formed in the joint portion of these containers, it can be said that it is substantially flat.
Note that the end face is not exposed when there is no step at the joint.
Further, it is not always necessary to use an adhesive, and it can be said to be an extremely inexpensive production method because it can be produced in a normal pulp molding line.
[0026]
Also, in a molding method of a pulp mold container in which a pulp slurry is sucked and dehydrated onto a paper mold and then pressed and dried with a heated press mold that fits together, a sheet of a predetermined shape based on a paper substrate, or an existing sheet is used. The molded product is placed on the surface of the press mold, and the molded intermediate surface that has been sucked and dehydrated on the paper mold is press-molded in such a manner that the sheet or the molded product is bonded. A sheet of a predetermined shape based on a paper base or a pre-molded product is fixed to the surface of the press die by providing a suction hole on the surface of the press die, etc. Adhere. A pulp mold container with higher bonding position accuracy is obtained.
[0027]
In addition, when the container strength is effectively improved by partially changing the flesh of the pulp material, the container strength can be improved by partially increasing the wall thickness without the need to modify the mold. Is possible.
[0028]
In addition, by adding as little chemical as possible to the outer layer of the container that does not require resistance to contents, etc., and using a member with functionality only on the inner layer of the container, it is possible to reduce unnecessary costs and minimize the environmental impact during disposal. It is possible to limit it to the limit.
[0029]
And in a pulp mold container that seals the opening with a lid material, when a member such as a polyolefin resin layer or a heat seal lacquer having excellent adhesion is provided only on the surface of the adhesion part with the lid material, a synthetic polymer material The amount used is minimized, and adhesion with the lid is good.
Furthermore, it is inexpensive to press with a press mold that fits together, but in the case of an advanced shape, pressing is performed sequentially or simultaneously using split molds that are not fitted together. It doesn't matter.
[0030]
Finally, by providing a fine color-printed label layer for gravure printing or offset printing, a pulp mold container having excellent cosmetic properties, which was not obtained by conventional printing on the surface of the pulp mold, can be obtained.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
The pulp material in the present invention may be waste paper pulp, virgin pulp, or appropriately mixed pulp, but when used in a primary container or the like, virgin pulp may be used. preferable. The pulp material may be wood pulp or non-wood pulp.
[0032]
The above pulp material is appropriately adjusted to a paper material such as disaggregation, beating, and internal addition, and is made into a pulp slurry having a pulp concentration of about 0.1 to 1%, and is sucked and dehydrated on a paper mold to obtain a mold intermediate. A sheet of a predetermined shape based on a paper base prepared in advance or a pre-molded product is placed on the mold intermediate and pressed with a heated press die that fits and dried. Or by providing a suction hole on the surface of the press die or the like to fix a sheet having a predetermined shape based on a paper base or a pre-molded product at a predetermined position on the surface of the press die, The pulp mold container of the present invention is obtained by hot pressing.
[0033]
Adhesion between a mold intermediate and a sheet of a predetermined shape based on a paper base, or a pre-molded product, moisture in the mold intermediate penetrates into the paper base of the sheet or pre-molded product, Since the surface tension of water attracts the pulp fibers in the mold intermediate and the pulp fibers in the paper substrate and press-drys, this is achieved by the formation of hydrogen bonds between the two pulp fibers. The moisture content of the mold intermediate is preferably adjusted to about 96 to 70%. If the water content is too small, the adhesion with a sheet having a predetermined shape based on a paper substrate or a pre-molded product will be insufficient. Conversely, if the water content is too high, the molded state will be deteriorated.
[0034]
In addition, the surface of the sheet having the predetermined shape and the mold intermediate of the pre-molded product must be uncoated paper that is not coated with anything other than a substance that acts as an adhesive. If there is a printing or coating layer on the adhesive surface, hydrogen bonding between pulp fibers is hindered, and sufficient adhesive strength cannot be obtained. Also, some adhesive components generate harmful substances during the incineration process, so it is desirable not to provide an adhesive layer if possible.
[0035]
The sheet having a predetermined shape is obtained by printing on a paper base material, laminating a functional agent coating, a thermoplastic resin, or the like as necessary, and punching it into a predetermined shape. Even if it is a layer, the multilayer structure which consists of several types of materials may be sufficient. Further, as the above-mentioned molded product, it is made of the same pulp material as the pulp material constituting the pulp mold container, and is separately molded by a pulp mold. If necessary, internal addition of a functionalizing agent, coating, impregnation, What was processed, such as laminating, is used.
[0036]
The pulp mold container of the present invention is characterized in that it is molded in-line, and is pressed and bonded in a press mold that fits together, so that it is bonded to the joint surface like offline bonding to a pulp mold molded body. The sheet having the predetermined shape or the pre-molded product is embedded in a pulp mold container without a step, and the surface is smooth and the end face is not exposed. Moreover, since an adhesive is not required, it can be said that the pulp mold container is low in cost and has little environmental load at the time of disposal.
[0037]
The shape of the pulp mold container of the present invention is not particularly limited, and may be a cup shape, a bowl shape, a tray shape, a partition, or the like. In the case of a container in which the upper surface of the container is sealed with a lid member, it is preferable that the opening has a flange portion as a seal portion.
[0038]
Hereinafter, the present invention will be described in detail with reference to the drawings and examples. However, the present invention is not limited to these drawings and examples. Drawing 1 is a mimetic diagram showing an example of the shape of the pulp mold container of the present invention. First, a papermaking mold corresponding to the shape shown in FIG. 1 and a press mold that fits each other were produced.
[0039]
The papermaking mold comprises a papermaking net corresponding to the shape shown in FIG. 1 and its receiving mold, and suction holes for suction dehydration are arranged in the receiving mold so that the thickness of the pulp material is uniform. The papermaking was produced in two types: a female mold in which the container-shaped opening 11 shown in FIG. 1 is made upward and a male mold in which the opening 11 is made downward. In addition, the press die was composed of a male die and a female die that fit each other in correspondence with the shape shown in FIG. The press die can be heated to 150 ° C. to 200 ° C., and suction holes are provided in the press die so that water vapor generated during press drying can be exhausted.
[0040]
(Comparative Example 1)
NBKP was beaten to 500 csf to obtain a pulp slurry having a concentration of 0.4%. The pulp slurry 2L is sucked and dehydrated onto the above-described female papermaking mold to obtain a mold intermediate, sandwiched by a press mold that fits together with the papermaking mesh, and hot-pressed at 150 ° C. and 0.4 MPa, FIG. A pulp mold container as shown in FIG.
[0041]
Example 1
An uncoated paperboard having a basis weight of 250 g / m ² is punched into a shape corresponding to the flange portion 12 of the pulp mold container opening 11 shown in FIG. A mold intermediate was prepared in the same manner as in Comparative Example 1, and the punched paperboard was placed on the flange portion, sandwiched between press molds that fit together with the papermaking net, and hot pressed at 150 ° C. and 0.4 MPa. A pulp mold container as shown in the sectional view of FIG. 2 was obtained. The compressive strength from the lateral direction of the present pulp mold container greatly depends on the thickness of the flange portion. When the buckling load at the time of compression was measured by the universal testing machine, the buckling load was increased about twice as compared with the pulp mold container of Comparative Example 1. Moreover, the adhesion state of the adhesion surface 23 in FIG. 2 was favorable.
[0042]
(Example 2)
NBKP was beaten to 350 csf to obtain a 0.4% concentration pulp slurry. Within this, polyacrylamide resin paper strength enhancer is 0.3% per dry-dry pulp weight, fluorine-based oil repellent is 0.5% per dry-dry pulp weight, and alkyl ketene dimer as sizing agent is within 1% per dry-dry pulp weight 1 L of the added pulp slurry was sucked and dehydrated on the above-mentioned female mold, sandwiched between press molds fitted together with the mesh, and hot-pressed at 150 ° C. and 0.4 MPa to obtain a pre-molded product. . Subsequently, 0.4 L-concentrated NBKP pulp slurry 1L beaten to 500 csf is sucked and dehydrated onto the female mold, and a mold intermediate is obtained. The paper net was sandwiched between press molds that were fitted together, and hot pressed at 150 ° C. and 0.4 MPa to obtain a pulp mold container as shown in a sectional view in FIG.
[0043]
The pulp mold container obtained in Example 2 was prepared by adding 0.3% of polyacrylamide resin paper strength enhancer to the pulp slurry used as the raw material of Comparative Example 1 per weight of dry pulp and 0% of fluorine-based oil repellent per weight of dry pulp. 5%, compared to a pulp mold container prepared by adding 1% of the alkyl ketene dimer as a sizing agent to the dry pulp weight, the amount of the agent used is 1/2, while the water resistance of the container inner layer surface, The water repellency was better. The adhesion state of the adhesion surface 33 was also good.
[0044]
Example 3
A paperboard having a basis weight of 250 g / m ² , in which 20 μm of polypropylene resin is laminated on one side, is punched into a shape corresponding to the flange portion 12 of the pulp mold container opening 11 shown in FIG. A mold intermediate was prepared in the same manner as in Comparative Example 1, and the punched composite sheet was sandwiched between press molds with the polypropylene resin surface placed on top and fitted together with the paper mesh, 150 ° C., It was hot-pressed at 0.4 MPa to obtain a pulp mold container as shown in a sectional view in FIG.
[0045]
For the pulp mold container of Example 3 and the pulp mold container of Comparative Example 1, a cover material having a layer configuration of paper / low density polyethylene / aluminum foil / EVA hot melt resin is used, and the flange portion 12 of the container opening 11 is used. It was made to adhere to by an impulse seal. The adhesive strength of the pulp mold container of Example 3 with the lid material was about 5 times that of the container of Comparative Example 1.
[0046]
(Example 4)
A high-quality paper having a basis weight of 81.4 g / m 2 was subjected to color printing by a gravure printing machine, and punched into a shape corresponding to the body portion 13 of the pulp mold container shown in FIG. 1 to produce a label. The label is sucked and fixed to the surface of the body portion of the press-type female die that fits together. A press intermediate (male mold and label) is obtained by sucking and dewatering 0.4% NBKP pulp slurry (2L) beaten to 500 csf onto the male paper mold to obtain a mold intermediate and fitting together with the paper mesh. Was fixed by hot pressing at 150 ° C. and 0.4 MPa to obtain a pulp mold container as shown in a sectional view in FIG.
[0047]
In the pulp mold container of Example 4, the outer layer surface was smooth, the container body and the label layer were integrated, and the cosmetics were excellent by fine gravure printing. On the other hand, when a relief printing such as a rubber plate is printed on the pulp mold container of Comparative Example 1, it is inferior in cosmetics with a single color, and when the label is wrapped around the pulp mold container of Comparative Example 1 offline, an adhesive is required, Furthermore, the label portion has a level difference, which makes it easy to peel off.
[0048]
【The invention's effect】
As described above, according to the present invention, it is possible to combine with a reinforcing member, a functionalized member, a label member, etc. without changing the shape of the pulp mold container and without using an adhesive. Does not require mold correction or offline joining equipment. In addition, since the amount of the synthetic polymer material used can be minimized, it is possible to minimize the influence on the safety, recyclability, and biodegradability of the original paper when incinerated.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of the shape of a pulp mold container of the present invention.
FIG. 2 is a cross-sectional view showing Example 1 of a pulp mold container of the present invention.
FIG. 3 is a sectional view showing Example 2 of the pulp mold container of the present invention.
FIG. 4 is a sectional view showing Example 3 of the pulp mold container of the present invention.
FIG. 5 is a sectional view showing Example 4 of the pulp mold container of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Pulp mold container 11 ... Opening part 12 ... Flange part 13 ... Trunk part 2 ... Pulp mold container 21 ... Molded pulp member 22 ... Paperboard member 23 stamped to predetermined shape ... Adhesive surface 3 ... Pulp mold container 31 ... Molded pulp member 32 ... Molded molding member 33 ... Adhesive surface 4 ... Pulp mold container 41 ... Molded pulp member 42 ... Composite sheet member 43 punched into a predetermined shape ... Adhesive surface 5 ... Pulp mold container 51 ... Molded pulp member 52 ... Print label member 53 ... Adhesive surface

Claims (2)

A step of suction dehydrating the pulp slurry on the paper mold to form a mold intermediate containing 70 to 96% water;
After the pulp slurry is sucked and dehydrated onto the mold, the mold intermediate is pressed with a press mold that fits and dried, and then a molded product that has been dried is placed and then 150 to 200 by a press mold that fits. And a step of forming a pulp mold container by press molding that is heated in a range of ° C. A method for producing a pulp mold container. A step of suction dehydrating the pulp slurry on the paper mold to form a mold intermediate containing 70 to 96% water;
After the pulp slurry is sucked and dehydrated onto the papermaking mold, the mold intermediate is placed on the surface of the pre-molded product after being placed on the surface of the press mold after being pressed and dried with a press mold that fits together. And a step of forming a pulp mold container by press forming by heating in a range of 150 to 200 ° C. with a press mold that overlaps and fits together .

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