JP2022042625A - Method of producing pulp mold molding - Google Patents

Abstract

To easily produce a sheet-like pulp mold molding of excellent surface designability at a low cost.SOLUTION: Among a plurality of processes in producing a pulp-mold molding, press work is carried out in a pressing process of applying press work to a sheet-shaped pulp-mold intermediate product W formed in a paper making process, with an embossing plate 6 having an embossed pattern on one face thereof kept in a state of being set onto a working face 5a of a lower side mold 5 in such a manner that its one face opposes the pulp-mold intermediate product W, to transfer the embossed pattern of the embossing plate 6 onto the lower face of the pulp-mold intermediate product W to form the embossed pattern on one face of the pulp-mold molding M. According to the constitution of the method, excellent designability can easily be obtained relative to a method in which the pressing temperature and pressure are changed, the cost is made lower than that of a method of forming an embossed pattern on the working face of a mold, and a pattern of the pulp-mold molding M can effortlessly be changed.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for producing a sheet-shaped pulp molded product.

Pulp molded products made from recycled paper and the like have been widely applied to packaging containers, cushioning materials, etc. due to the recent trend toward deplasticization. In addition, interior products that take advantage of the unique texture of the surface are becoming available.

Generally, the method for producing this pulp molded product is a pulp slurry in which a raw material such as used paper is dissolved in water to form a pulp slurry (a fluid containing pulp fibers), and the pulp slurry is treated to remove foreign substances. A raw material adjustment process that adjusts the properties of the pulp mold, an extraction process that extracts pulp fibers from the adjusted pulp slurry to form a pulp mold intermediate product, and a pulp mold that presses the molded pulp mold intermediate product. It includes a pressing process for making a molded product and a finishing process for punching out a pulp molded product to finish the product.

The actual work of the above-mentioned extraction process is to immerse a mold having a shape corresponding to the shape of the product and having a plurality of holes in a pulp slurry with a wire mesh attached to the surface thereof, and reduce the pressure inside the mold. , The method of adhering the pulp fibers in the pulp slurry to the wire mesh (so-called pulp molding method) is often used.

In the actual work of the pressing process, the pulp mold intermediate product removed from the mold and wire mesh after the extraction process is sandwiched between upper and lower dies having a processed surface having a shape corresponding to the product shape, and the predetermined temperature and pressure are obtained. By pressing with, the shape and surface texture are adjusted. The press working is performed by either a dry method or a wet method. The dry method is a method in which the pulp mold intermediate product is dried (dehydrated) and then press-processed, and the wet method is a method in which the pulp mold intermediate product is press-processed in a moist state and then dried (dehydrated).

By the way, many of the products using pulp-molded products have traditionally been made into a three-dimensional shape at the manufacturing stage of the pulp-molded products, but recently, pulp-molded products formed into sheet shapes have been used. An increasing number of products are used in their original shape or folded into a three-dimensional shape.

Then, in the method for manufacturing a sheet-shaped pulp-molded product as described above, a product having a different surface appearance is manufactured by changing the temperature and pressure when the pulp-molded intermediate product is pressed in the pressing process. It has also been proposed that it can be applied as a mount having a different surface design (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-183350

However, in the method for manufacturing a sheet-shaped pulp-molded product proposed in Patent Document 1, the difference in the surface appearance of the manufactured pulp-molded product causes unevenness on the side opposite to the wire net in the extraction process. It cannot be said that the range of variations in the surface design is wide because it is only due to the difference in the way the mesh marks on the wire mesh side are crushed by press working.

On the other hand, when manufacturing a sheet-shaped pulp molded product, an uneven pattern is provided on at least one of the processed surfaces of the upper and lower dies used in the pressing process, and the uneven pattern is formed by pressing the pulp mold. It is considered that the surface design of the pulp-molded product can be significantly improved by transferring it to the intermediate product.

However, in the method of transferring the uneven pattern of the mold to the pulp mold intermediate product in the pressing process as described above, the same number of molds as the required pattern type are prepared, and the unevenness on the processed surface of each mold is different. It is necessary to provide a pattern, and the cost of the mold becomes very high. Further, when changing the pattern of the pulp molded product to be manufactured, there is a drawback that it takes time and effort to replace the mold.

Therefore, it is an object of the present invention to make it possible to easily manufacture a sheet-shaped pulp molded product having excellent surface design at low cost.

In order to solve the above problems, the present invention is to immerse a flat reticulum in a pulp slurry and attach pulp fibers to the reticulum to form a sheet-shaped pulp mold intermediate product. A pulp mold molded product including a picking process and a pressing step of sandwiching the pulp mold intermediate product molded in the extraction step between upper and lower molds and pressing to obtain a sheet-shaped pulp mold molded product. In the manufacturing method of the above, in the pressing step, an embossing plate having an uneven pattern formed on one surface is set on at least one of the processed surfaces of the upper and lower molds so that one surface faces the pulp mold intermediate product. In this state, press processing was performed to transfer the uneven pattern of the embossing plate to at least one of the upper and lower surfaces of the pulp mold intermediate product.

According to the above configuration, when a sheet-shaped pulp-molded product is manufactured, various uneven patterns can be formed on one or both sides of the pulp-molded product by using an embossing plate in the pressing process. Superior surface design can be easily obtained as compared with the method of changing the temperature and pressure at the time of pressing to make the surface appearance of the pulp molded product different. In addition, compared to the method of providing uneven patterns on the machined surface of the mold, it is possible to prepare embossing plates with various patterns at low cost, and the pulp mold can be easily obtained by simply replacing the embossing plate set in the mold. The pattern of the molded product can be changed.

As described above, in the method for producing a pulp molded product of the present invention, in the pressing process, a press working is performed with an embossing plate set in at least one of the upper and lower dies, and the pulp mold intermediate product is formed into a mold. Since the uneven pattern of the stamping plate is transferred, it is possible to easily impart surface design superior to the sheet-shaped pulp molded product, which is superior to the method of changing the temperature and pressure at the time of pressing. Can be done. Further, the cost is lower than the method of providing the uneven pattern on the machined surface of the mold, and the work at the time of changing the pattern can be easily performed.

Longitudinal front view illustrating an extraction process of a method for manufacturing a pulp molded product of an embodiment. External perspective view of the formwork used in the extraction process of FIG. Top view of the upper side surface of the pulp mold intermediate product molded in the extraction process of FIG. Top view of the lower side surface of the pulp mold intermediate product of FIG. (A) and (b) are vertical sectional front views explaining a pressing process following the extraction process of FIG. 1 ((b) is an enlarged view of a main part). Top view of the embossing plate used in the pressing process of FIG. External perspective view showing the main part of the embossing plate of FIG. 6 in an enlarged manner. Top view of the lower side surface of the pulp molded product obtained by the pressing step of FIG. External perspective view showing a part of the pulp molded product of FIG. 8 in an enlarged manner.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The manufacturing method of this pulp molded product is basically the same as the above-mentioned general method, and a melting step, a quality adjusting step, an extraction step, a pressing step and a finishing step are performed in order to form a sheet. It manufactures pulp molded products.

Although not shown, the melting step is a step of dissolving a raw material such as used paper in water to form a pulp slurry, and the raw material adjusting step is a process of removing foreign substances from the pulp slurry supplied from the melting step. This is a step of adjusting the properties of the pulp slurry.

As shown in FIG. 1, the extraction step is a step of extracting pulp fibers from the pulp slurry S supplied to the immersion tank 1 from the raw material adjusting step to form a sheet-shaped pulp mold intermediate product W. be. In this extraction step, the mold 2 as shown in FIG. 2 is used. The formwork 2 is a metal rectangular frame 2a to which a flat wire mesh (net-like body) 2b covering an opening on one side thereof is attached. In addition, instead of the wire mesh, a resin mesh body can also be used.

Then, as shown in FIG. 1, the above-mentioned mold 2 is attached to the flat plate-shaped suction portion 3a of the suction device 3 arranged above the immersion tank 1, and the suction device 3 is driven to drive the suction device 3 to pulp the mold 2. Suction is performed while immersed in the slurry S. As a result, the pulp fibers in the pulp slurry S adhere to the lower surface side of the wire mesh 2b of the mold 2, and the sheet-shaped pulp mold intermediate product W is formed.

The pulp mold intermediate product W formed as described above is removed from the mold 2 after the mold 2 is pulled up from the pulp slurry S. The pulp mold intermediate product W removed from the mold 2 has a flatter surface side (the side facing the wire mesh 2b at the time of molding) than the back surface side. Then, as shown in FIG. 3, the mesh marks of the wire mesh 2b are formed almost uniformly on the front surface side, and as shown in FIG. 4, the depth and area of the wire mesh 2b are formed on the back surface side as compared with the mesh marks on the front surface side. Irregular unevenness is formed.

In the pressing step, as shown in FIGS. 5A and 5B, the pulp mold intermediate product W is sandwiched between the processing surfaces 4a and 5a of the upper and lower dies 4 and 5 and pressed, and the pulp mold is formed. It is a process of forming a molded product M, and a dry method is adopted for the press working. In this pressing process, a metal embossing plate 6 as shown in FIGS. 6 and 7 is used. The embossed plate 6 has a concave-convex pattern in which rectangular recesses 6a are uniformly formed in a brickwork shape on one surface thereof, and the other surface is flat.

When performing press working in this pressing process, first, the pulp mold intermediate product W formed in the extraction process is dried, and then, as shown in FIG. 5A, the above-mentioned embossing plate 6 is performed. Is set on the machined surface 5a of the lower die 5 so that the recess 6a faces upward, and the dried pulp mold intermediate product W is placed on the embossing plate 6 in a posture in which the surface with the mesh mark is the upper surface. In the state of being placed, the upper mold 4 is lowered. Then, as shown in FIG. 5B, the pulp mold intermediate product W is pressed at a predetermined temperature and pressure by the upper and lower dies 4 and 5 and the embossing plate 6, and the shape is adjusted and the mold is formed on the lower surface. The uneven pattern of the stamp 6 is transferred to obtain a pulp molded product M.

In addition, since the embossed plate may cause overall undulation during production, when using such an embossed plate, attach it to a flat plate on the lower surface of the embossed plate, and attach it to the plate and the lower side. It is advisable to insert paper or the like between the die and the embossing plate so as to compensate for the unevenness of the height of the embossing plate so that uniform pressure is applied to the entire surface of the pulp mold intermediate product.

As shown in FIGS. 8 and 9, in the pulp molded product M obtained as described above, the convex portion Ma corresponding to the concave portion 6a of the embossing plate 6 is bricked on the lower surface when pressed. It is formed uniformly in a shape, and traces of irregular irregularities formed in the extraction process remain on the surface layer. Further, although not shown, a slight amount of mesh marks formed in the extraction step remains on the upper surface of the press-processed surface.

Then, this pulp molded product M is sent from the pressing process to the finishing process and punched into a predetermined shape (in this example, the substantially square shown by the alternate long and short dash line in FIG. 8) to become a product, which is used as a mount or interior of a packaging container. It will be used as a base material for products.

This method for manufacturing a pulp-molded product comprises the above-mentioned plurality of steps, and in the pressing process, the pulp-molded intermediate product W is pressed with the embossing plate 6 set in the lower die 5. By transferring the uneven pattern of the embossing plate 6 to the lower surface thereof, the uneven pattern is formed on one surface of the pulp molded product M, so that the temperature and pressure at the time of conventional pressing are changed. It is easy to obtain better surface design than that. Further, the cost is lower than the method of providing the uneven pattern on the processed surface of the mold, and when changing the pattern of the pulp molded product M, it is only necessary to replace the embossing plate 6, so that the workability is improved. It is also advantageous in terms of.

In this embodiment, the press working of the pulp molded product in the pressing process is performed by a dry method, but the press working may be performed by a wet method.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

For example, in the pressing process of the embodiment, the embossing plate is set in the lower mold so that the uneven pattern is transferred to the lower surface of the pulp mold intermediate product, but the embossing plate is placed in the upper mold or the upper and lower molds. It may be set in both molds so that the uneven pattern is transferred to the upper surface or both the upper and lower surfaces of the pulp mold intermediate product.

Further, when the uneven pattern of the embossing plate is transferred to one surface of the pulp mold intermediate product, the one surface may be a surface having irregular irregularities formed in the extraction process as in the embodiment, or a mesh in the extraction process. It may be a surface on which a mark is formed.

Further, the uneven pattern of the embossing plate to be transferred to one side or both sides of the pulp mold intermediate product is not limited to the brick-laying pattern as in the embodiment, and various patterns can be adopted.

1 Immersion tank 2 Formwork 2a Rectangular frame 2b Wire mesh (mesh)
3 Suction device 3a Suction part 4, 5 Mold 4a, 5a Machined surface 6 Stamping plate 6a Recessed S Pulp slurry W Pulp mold intermediate product M Pulp mold molded product Ma Convex part

Claims (1)

A extraction step of forming a sheet-shaped pulp mold intermediate product by immersing a flat net-like body in a pulp slurry and adhering pulp fibers to the net-like body, and a pulp formed in the above-mentioned extraction step. In a method for manufacturing a pulp molded product, which includes a pressing step of forming a sheet-shaped pulp molded product by sandwiching a mold intermediate product between upper and lower dies and pressing the product.
In the pressing step, a stamping plate having an uneven pattern formed on one surface is set on at least one of the processed surfaces of the upper and lower dies so that one surface faces the pulp mold intermediate product. A method for producing a pulp-molded product, wherein the uneven pattern of the embossing plate is transferred to at least one of the upper and lower surfaces of the pulp-molded intermediate product.

Images