JP2000309323A - Multilayered pulp mold hollow molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molding which is uniform in thickness, free from cracks at the time of paper-making and excellent in transferability of a mold surface shape by making innermost and outermost layers using pulp fibers which have respective specific weighted average fiber lengths, Canadian standard freeness and fiber length frequency distribution as materials. SOLUTION: An innermost layer 1 and an outermost layer 2 of a molding employ two kinds of slurry each containing pulp fibers different in physical properties as paper-making materials. The pulp fibers for the innermost layer 1 may comprise fibers wherein an average fiber length is 0.8 to 2.0 mm, freeness is 100 to 600 cc, fibers with a fiber length of 0.4 to 1.4 mm in a fiber length frequency distribution occupy 20 to 90% of a total while fibers with a fiber length of 1.4 to 30 mm occupy 5 to 50% of a total. The pulp fibers for the outermost layer 2 may comprises fibers wherein an average fiber length is 0.2 to 1.0 mm, freeness is 50 to 60 cc, and fibers with a fiber length of 0.1 to 1.4 mm occupy 50 to 95% of a total.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer pulp mold hollow molded article using a slurry containing a specific pulp fiber as a raw material for papermaking.

[0002]

2. Description of the Related Art Attempts have been made to improve the performance of pulp molded articles by using specific pulp fibers. For example, JP-A-8-929
The technique described in Japanese Patent Publication No. 00 is to increase the water resistance and wet strength of the obtained molded body by filling the voids between the pulp fibers in the pulp mold made of the pulp fibers having a low degree of destruction with a high degree of pulp. The purpose is. The technique described in Japanese Patent Application Laid-Open No. 8-158299 discloses a method of forming a slurry containing a fibrillated plant fiber and a non-fibrillated fiber in a predetermined ratio as a forming raw material, thereby obtaining the hydrogen bonding degree of the plant fiber. It is intended to suppress the deformation, increase the flexibility and elasticity of the obtained molded body, and reduce the deformation due to shrinkage.

However, even if any of the fibers described in the above-mentioned publications is used, it is impossible to obtain a molded article having a uniform thickness and which does not crack during papermaking. Further, the surface shape of the mold is not faithfully transferred to the obtained molded body, and it is not possible to obtain a molded body excellent in surface smoothness or a molded body in which small irregularities are faithfully transferred. Is called transferability).
In particular, in a hollow molded body having an opening, a body, and a bottom, a hollow molded body having a large depth cannot be obtained without forming a joint in the body.

Accordingly, an object of the present invention is to provide a multi-layer pulp molded hollow molded article having a uniform wall thickness, no cracking during papermaking, and excellent in mold surface shape transferability.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a multilayer pulp molded hollow molded article having an outermost layer and an innermost layer,
The innermost layer has a length-weighted average fiber length of 0.8 to 2.0 m.
m, 100 Canadian Standard Freeness
６００600 cc and a fiber length of 0.1 in the fiber length frequency distribution.
Fibers in the range of 4 mm or more and 1.4 mm or less are 20-
Fibers occupying 90% and in a range of more than 1.4 mm and 30 mm or less are formed using a slurry containing pulp fibers occupying 5 to 50% of the whole, and the outermost layer has a length-weighted average fiber length. 0.2-1.0 mm, Canadian Standard Freeness 50-600 cc, and pulp fibers in which the fiber length is 0.4 mm or more and 1.4 mm or less in the frequency distribution of the fiber, which accounts for 50-95% of the whole. The above object has been achieved by providing a multilayer pulp mold hollow molded body formed by using a slurry containing the same.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a multilayer pulp mold hollow molded article (hereinafter, simply referred to as a molded article) of the present invention will be described based on preferred embodiments with reference to the drawings. The molded body of the present embodiment has a three-layer structure as shown in FIG.
It has an innermost layer 1 and an outermost layer 2 and a mixed layer 3 between both layers. The innermost layer 1 and the outermost layer 2 are each formed using two types of slurries containing pulp fibers having different physical properties as papermaking raw materials. Each pulp fiber has a length-weighted average fiber length (hereinafter simply referred to as “average fiber length”), a value relating to the Canadian Standard Freeness (hereinafter simply referred to as “freeness”) and a frequency distribution of the fiber length within a specific range. Some are used. By forming a multilayer molded body from such two kinds of slurries, it is possible to obtain a molded body which is free from thickness unevenness, does not crack during papermaking, and has excellent mold surface shape transferability. The average fiber length referred to in the present specification refers to a value obtained by measuring the frequency distribution of the fiber length of the pulp fiber and calculating the length-weighted average. For measurement, use a KAJAANI FS-200 fiber length measuring instrument (Valmet Automation Co., Ltd.)
The measurement conditions were a fiber count of 20,000 or more.

The pulp fibers contained in the slurry forming the innermost layer 1 (hereinafter, this slurry is referred to as the slurry for the innermost layer) has an action of mainly preventing the occurrence of cracks and thickness unevenness during papermaking. The pulp fibers have an average fiber length of 0.8 to 2.0 mm, preferably 0.9 to 1.
8 mm, more preferably 1.0 to 1.5 mm is used. If the average fiber length is less than 0.8 mm, cracks may occur in the molded article during papermaking or drying, or the molded article may be inferior in mechanical properties such as impact strength.
If the thickness exceeds mm, the thickness of the pulp layer formed during papermaking tends to be uneven, and the surface smoothness of the molded product is poor.

The pulp fiber has a freeness of 100 to 600 cc, preferably 200 to 500 cc.
c, more preferably 300 to 400 cc. If the freeness is less than 100 cc, the drainage is too low to speed up the molding cycle, resulting in poor dewatering of the molded article. If it exceeds 600 cc, the drainage is too high and the pulp layer formed during papermaking has uneven thickness. Occurs.

Further, in the pulp fiber, fibers having a fiber length in a range of 0.4 mm or more and 1.4 mm or less (hereinafter, this range is referred to as range A) occupy 20 to 90% of the whole in the frequency distribution of the fiber length. In addition, a fiber in which fibers having a range of more than 1.4 mm and 30 mm or less (hereinafter, this range is referred to as range B) occupies 5 to 50% of the whole fiber is used. An example of the frequency distribution of the fiber length of the pulp fiber preferably used as the pulp fiber contained in the innermost slurry is as shown in FIG. 2, and the area of the range A portion in the frequency distribution curve (shown by hatching in the figure) ) Corresponds to the proportion (%) of pulp fibers having a fiber length in the range A. Similarly, the ratio of the area of the portion of the range B (shown by oblique lines in the drawing) to the entire area in the frequency distribution curve corresponds to the ratio (%) of the pulp fiber having the fiber length of the range B. By using the pulp fiber having such a frequency distribution, the average fiber length and the freeness are kept within the above ranges, the thickness is uniform, cracks are not generated during paper making, and the surface is smooth. A molded article having excellent properties can be obtained. Pulp fibers having a fiber length in the range A preferably account for 30 to 80%, more preferably 35 to 65%, and pulp fibers having a fiber length in the range B preferably 7.5 to 40%, more preferably. Is 10
Accounts for ~ 35%.

In particular, as shown in FIG. 2, it is preferable to have the frequency distribution peaks P _A and P _B in the range A and the range B, respectively, from the viewpoint of further enhancing the above-mentioned effects.

Pulp fibers having the above average fiber length, freeness, and frequency distribution of fiber lengths include, for example, types (eg, NBKP, LBKP, waste paper pulp), beating conditions (eg, fibrillation or cutting of pulp fibers), It can be obtained by controlling the blending conditions of a plurality of types of pulp. In particular, the average fiber length is 1.5 to 30
mm long pulp fiber, average fiber length 0.3 ~
It is possible to obtain a pulp fiber by blending a relatively short pulp fiber of 1.0 mm with a former / latter blend ratio of 90/10 to 40/60 (by weight).
It is preferable because a molded article having high surface smoothness can be obtained.

The pulp fibers contained in the slurry forming the outermost layer 2 (hereinafter, this slurry is referred to as the slurry for the outermost layer) mainly has an effect of improving the transferability of the mold surface shape, and the pulp fibers The average fiber length is 0.2 to
Those having a diameter of 1.0 mm, preferably 0.25 to 0.9 mm, more preferably 0.3 to 0.8 mm are used.
If the average fiber length is less than 0.2 mm, the yield of the pulp layer formed during papermaking is inferior (the amount of pulp fibers passing through the mesh of the net increases). A molded product having poor transferability or surface smoothness of the papermaking surface will be obtained.

The pulp fiber has a freeness of 50 to 600 cc, preferably 100 to 500 cc.
c, more preferably 200 to 400 cc. If the freeness is less than 50 cc, the drainage is too low, it is difficult to shorten the molding cycle, and the molded product is poorly dewatered. If it exceeds 600 cc, the drainage is too high, and the pulp layer formed during papermaking has too much water. Thickness unevenness occurs.

Further, as the pulp fibers, fibers having a fiber length in the range of 0.4 mm to 1.4 mm (range A) in the frequency distribution of the fiber length are 50 to 95%, preferably 60 to 95% of the whole. More preferably, those occupying 70 to 95% are used. By using the pulp fiber having such a frequency distribution, the average fiber length and the freeness are combined with the above ranges, and the thickness is uniform, the paper does not crack at the time of paper making, the surface is smooth, and the mold is prepared. A molded article having excellent transferability of the shape of the paper surface is obtained. In this case, the fiber length 1.
There is no particular limitation on the proportion of pulp fibers of more than 4 mm and pulp fibers of 0.4 mm or less.

The pulp fiber having the above average fiber length, freeness and frequency distribution of the fiber length can be obtained by the same means as the pulp fiber contained in the slurry for the innermost layer.
In particular, it is preferable to obtain the pulp fiber by cutting, since the efficiency of shortening the fiber is improved.

The slurry for the innermost layer and the slurry for the outermost layer may each be composed of the above-mentioned pulp fiber and water, or in addition thereto, an inorganic substance such as talc or kaolinite, an inorganic fiber such as glass fiber or carbon fiber, or the like. It may contain components such as powder or fiber of synthetic resin such as polyolefin, non-wood or vegetable fiber, and polysaccharide. The compounding amount of these components is preferably 1 to 70% by weight, particularly preferably 5 to 50% by weight, based on the total amount of the pulp fiber and the components. It is also preferable that the slurry for the innermost layer and / or the slurry for the outermost layer contain a raw material of Japanese paper.

Since the molded article of the present embodiment has a multilayer structure, it is possible to individually impart a function to each layer. For example, only the outermost layer 2 can be a colored layer by blending a coloring substance, for example, a coloring agent such as a pigment or a dye, a colored synthetic fiber, or a raw material of Japanese paper only into the slurry for the outermost layer. Mixing a colorant only in the slurry for the outermost layer is performed when a pulp having relatively low whiteness, for example, a pulp made of waste paper such as deinked pulp is mixed with the slurry (for example, a whiteness of 60% or more, (Especially 70% or more), since the color tone can be easily adjusted, the amount of the coloring agent can be reduced, and the molded article can be manufactured at low cost. The compounding amount of the coloring substance is preferably 0.1 to 15% by weight of the compounding amount of the pulp fiber. Further, it is preferable because the amount of deinked pulp used is reduced and a molded article can be produced at low cost.

Further, by adding additives such as a water repellent, a water resistant agent, a moisture proofing agent, a fixing agent, a fungicide, and an antistatic agent to the slurry for the outermost layer, the A function corresponding to the function can be provided. The outermost layer 2 containing these additives has a surface tension of 10 dyn / cm.
And the water repellency (JIS P8
137) is preferably R10. Further, by mixing powder or fiber of a thermoplastic synthetic resin with the slurry for the outermost layer, the outermost layer 2 can be provided with abrasion resistance, and fuzzing and the like can be suppressed. The degree of the abrasion resistance is preferably 3H or more as represented by pencil scratching strength (JIS K 5400).

In the molded article of the present embodiment, as shown in FIG. 1, a mixed layer 3 is interposed between an innermost layer 1 and an outermost layer 2. The mixed layer 3 is a layer whose composition continuously changes from the composition of the outermost layer 2 to the composition of the innermost layer 1. Since the mixed layer 3 is interposed between the innermost layer 1 and the outermost layer 2, the bonding strength between the innermost layer 1 and the outermost layer 2 is increased, and delamination between both layers is effectively prevented. The formation of the mixed layer 3 between the innermost layer 1 and the outermost layer 2 can be confirmed by microscopic observation of a cross section of the molded body.

The thickness of each of the innermost layer 1, the outermost layer 2, and the mixed layer 3 can be appropriately determined according to the use of the molded article. In particular, the thickness of the innermost layer is 3 times the thickness of the entire molded body.
A content of 0 to 95%, particularly 50 to 90%, is preferable because cracks and uneven thickness can be effectively prevented from occurring during molding. Also, the thickness of the outermost layer 2 is 10 times the thickness of the entire molded body.
% Or more and less than 50% is preferable because, when pulp fibers having low whiteness are used for the inner layer side, sufficient hiding properties can be exhibited from the outside. The thickness of each layer is determined by the injection amount and concentration of the slurry at the time of manufacturing the molded body.

The method for producing the molded article of the present invention is not particularly limited, and for example, the methods described in JP-B-51-34002 and JP-A-8-232200 can be used. Further, when manufacturing a hollow molded body having an opening, a body, and a bottom, a slurry for the outermost layer is formed in the cavity of a mold in which a cavity is formed by abutting a pair of papermaking split dies. It is preferable to use a method of injecting the slurry for the innermost layer into the cavity after injecting, since a hollow molded body having no joint in the body can be obtained. In particular, when manufacturing a molded article in which the mixed layer 3 as shown in FIG. 1 is interposed between the innermost layer 1 and the outermost layer 2,
The slurry for the outermost layer is injected under pressure into the cavity; the inside of the cavity is dehydrated to form the outermost layer 2 on the inner surface of the cavity.
The slurry for the innermost layer is injected under pressure into the cavity while forming the cavity; the inside of the cavity is further dewatered, and the composition of the outermost layer 2 is changed to the composition of the innermost layer 1 on the outermost layer 2. It is preferable to use a method of forming the mixed layer 3 whose composition is continuously changed and forming the innermost layer 1 on the mixed layer 3. FIG. 3 is a process diagram sequentially showing a paper making process of the process of manufacturing a molded article having the structure shown in FIG. 1 by such a method, wherein (a) shows a process of injecting a slurry for the outermost layer, b) dehydrating the slurry for the outermost layer and injecting the slurry for the innermost layer, (c) dehydrating the slurry for the innermost layer, (d) inserting the core, (e) pressing and dehydrating,
(F) is a step of opening the mold.

First, as shown in FIG. 3A, a mold 10 in which a cavity 13 having a shape corresponding to the outer shape of a molded body to be molded is formed by abutting a pair of split molds 11, 12 with each other. A predetermined amount of the slurry I for the outermost layer is injected into the cavity 13 from the upper opening portion under pressure. Each split mold 1
A plurality of communication holes 14 for communicating the outside with the cavity 13 are provided in the first and the second 12, respectively. The inner surfaces of the split dies 11 and 12 are covered with nets (not shown) each having a mesh of a predetermined size. For example, a pump is used for pressure injection of the slurry I for the outermost layer. The pressure for the pressure injection of the slurry I for the outermost layer is preferably 0.01 to 5 MPa, more preferably 0.01 to 3 MPa.
a.

Since the inside of the cavity 13 is pressurized,
The water in the slurry for the outermost layer is discharged out of the mold 10 and the pulp fibers in the slurry for the outermost layer are deposited on the inner surface of the cavity 13 as shown in FIG. The outermost layer 2 is formed. Next, the innermost layer slurry II is injected under pressure into the cavity 13 from the upper opening of the mold 10. Thus, a mixed slurry of the slurry for the outermost layer and the slurry for the innermost layer exists in the cavity 13. Slurry for innermost layer
The pressure of the pressure injection of II can be substantially the same as the pressure of the pressure injection of the slurry I for the outermost layer.

When dehydration in the cavity 13 is continuously performed together with the injection of the slurry for the innermost layer under pressure, a mixed layer (not shown) of pulp composed of the components of the mixed slurry is formed on the outermost layer 2. In this case, in the mixed slurry, the ratio of the innermost layer slurry can be increased over time and continuously as compared with the ratio of the outermost layer slurry. Means that the composition continuously changes from the composition of the slurry for the outermost layer to the composition of the slurry for the innermost layer.

As shown in FIG. 3C, the slurry for the innermost layer
When pressure and dehydration are continuously performed by injecting pressure II, the composition of the mixed slurry in the cavity 13 finally becomes the same as the composition of the slurry for the innermost layer, and as a result, as shown in FIG. Then, the innermost layer 1 on which the components of the innermost layer slurry are deposited is formed on the mixed layer.

As described above, in the present manufacturing method, since the slurry I for the outermost layer and the slurry II for the innermost layer are continuously injected into the cavity 13, a molded article can be efficiently manufactured.

When the innermost layer 1 having a predetermined thickness is formed, the injection of the innermost layer slurry under pressure is stopped, and air is injected into the cavity 13 to depressurize and dehydrate. Subsequently, FIG.
As shown in (1), the press-in of the air is stopped, the inside of the cavity 13 is sucked and decompressed, and the elastic, expandable and hollow core 18 is inserted into the cavity 13.
The core 18 is inflated like a balloon in the cavity 13 to press a laminate (hereinafter, referred to as a pulp laminate) composed of an innermost layer, a mixed layer, and an outermost layer against the inner surface of the cavity 13, thereby forming the cavity 13. Used to give internal shape. Therefore, the core 18 is made of urethane, fluorine-based rubber, silicone-based rubber, elastomer, or the like which is excellent in tensile strength, rebound resilience, elasticity and the like.

Next, as shown in FIG.
The core 18 is expanded by supplying a pressurized fluid therein, and the molded body is pressed against the inner surface of the cavity 13 by the expanded core 18. Then, the pulp laminate is pressed against the inner surface of the cavity 13 by the expanded core 18, and the inner surface shape of the cavity 13 is transferred to the pulp laminate, and dehydration further proceeds. As described above, since the pulp laminate is pressed against the inner surface of the cavity 13 from the inside of the cavity 13, even if the shape of the inner surface of the cavity 13 is complicated, the shape of the inner surface of the cavity 13 is accurately adjusted. Will be transcribed. In addition, unlike the conventional pulp mold manufacturing method, since there is no need to use a bonding step, the obtained molded article does not have a seam or a thick portion due to bonding. As a result, the strength of the obtained molded body is increased and the appearance impression is improved. As the pressurized fluid used to expand the core 18, for example, compressed air (heated air), oil (heated oil), and other various liquids are used. Further, the pressure for supplying the pressurized fluid is 0.01 to 5 MPa, especially 0.1 to 5 MPa.
It is preferable to make it 1 to 3 MPa.

When the shape of the inner surface of the cavity 13 is sufficiently transferred to the pulp laminate and the pulp laminate can be dehydrated to a predetermined moisture content, as shown in FIG. Pull out. Then, the core 18 automatically shrinks and returns to its original size. Next, the contracted core 18 is taken out from the cavity 13, and the mold 10 is further opened to take out a wet pulp laminate 19 having a predetermined moisture content.

The removed pulp laminate 19 is then subjected to a heating and drying process. In the heating / drying step, the same operation as the paper making step shown in FIG. 3 is performed except that the paper making / dewatering is not performed. That is, first, a mold in which a cavity having a shape corresponding to the outer shape of a molded body to be molded is formed by abutting a pair of split molds is heated to a predetermined temperature, and the mold is wet in the heated mold. Of the above pulp laminate.

Next, a core similar to the core 18 used in the papermaking step was inserted into the pulp laminate, and a pressurized fluid was supplied into the core to expand the core. The pulp laminate is pressed against the inner surface of the cavity by the core. The material of the core and the supply pressure of the pressurized fluid can be the same as in the above-described papermaking process. In this state, the pulp laminate is heated and dried. The pulp laminate,
When the core is sufficiently dried, the pressurized fluid in the core is drained, and the core is contracted and taken out. Further, the mold is opened, and the molded article is taken out.

As shown in FIG. 3 (g), the molded body 4 of the present embodiment obtained as described above has a cylindrical bottle (hollow container) in which the diameter of the opening 5 is smaller than the diameter of the body 6. )
And is suitably used for accommodating contents such as powders and granules. The molded body 4 has no joint at any of the opening 5, the body 6 and the bottom 7, and the opening 5, the body 6
And the bottom 7 are integrally formed. Therefore, the strength of the molded body 4 is increased and the appearance impression is improved. In addition, the transfer of the shape of the portion such as the rising portion from the bottom 7 to the body 6 where the transfer of the surface shape of the mold is not easy or the case where the screw is formed in the opening 5 is also performed well.

The molded article of the present invention may have a multilayer structure rather than the layer structure shown in FIG. Further, after the molded article is formed, a plastic layer or a coating layer is provided on an outer surface and / or an inner surface to further enhance the strength of the molded article, effectively prevent leakage of contents, or decorate. May be applied. In addition, a reinforcing member made of plastic or the like may be disposed at a portion where a load is applied when the molded body is used, for example, an opening or a bottom, so that the durability of the molded body may be improved. Further, some of these parts may be formed of plastic or the like. Further, the molded article of the present invention may be a substantially rectangular parallelepiped carton-type container in which the cross-sectional shape of the opening and the cross-sectional shape of the body are substantially the same. Further, the molded article of the present invention may be applied not only to a hollow container used for housing contents but also to an object such as an ornament.

[0034]

EXAMPLES In the following Examples and Comparative Examples, "%" means "% by weight" unless otherwise specified.

[Examples 1 to 4 and Comparative Examples 1 to 3] An upper opening of a papermaking mold in which a cavity having a shape corresponding to the outer shape of a molded body to be molded is formed by abutting a pair of split dies. A slurry for the outermost layer containing 1.0% of pulp fibers having the physical properties shown in Table 1 below was injected into the cavity from the portion at a pressure of 0.3 MPa. The inside of the cavity was dehydrated to form an outermost layer of the slurry for the outermost layer on the inner surface of the cavity. In parallel with the formation of the outermost layer, a slurry for the innermost layer containing 1.0% of pulp fibers having the physical properties shown in Table 1 below was injected into the cavity at a pressure of 0.3 MPa. Furthermore, air is injected into the cavity from the upper opening of the mold at a pressure of 0.1 MPa, and the composition continuously changes from the composition of the slurry for the outermost layer to the composition of the slurry for the innermost layer on the outermost layer. The mixed layer was formed, and the innermost layer was formed on the mixed layer by the slurry for the innermost layer. A core made of an elastic material is inserted into the pulp laminate obtained in this way, and air is applied to the core at a pressure of 1.5 MPa.
The pulp laminate was pressed against the inner surface of the cavity to perform further dehydration. Next, the papermaking mold was opened to take out the pulp laminate, which was loaded into a heating mold. The heating mold has a cavity having the same shape as the papermaking mold. A core made of an elastic material is inserted into the pulp laminate loaded in the heating mold, and air is supplied to the core at a pressure of 1.5 MPa.
And the heating mold was heated to 200 ° C. while the pulp laminate was pressed against the inner surface of the cavity to dry the pulp laminate. When the pulp laminate was sufficiently dried, the heating mold was opened, and a bottle-shaped molded product was taken out.

Table 1 shows the moldability of the obtained molded body. Also, the surface roughness of the molded product was measured by Surfcom 12 of Tokyo Seimitsu Co., Ltd.
Measured by OA. The transferability of the cavity inner surface shape to the molded product was visually evaluated. Further, a 70 mm long × 20 mm wide section was cut out from the obtained molded body, and this section was peeled off at the mixed layer portion to prepare a Y-shaped sample piece. This sample piece was mounted on a tensile tester with a distance between chucks of 20 mm, and a 180 ° peel test was performed at a tensile speed of 30 mm / min. Table 1 shows the results.

Example 5 The procedure of Example 5 was repeated except that the slurry for the outermost layer was injected into the cavity to completely form the outermost layer, and then the slurry for the innermost layer was injected into the cavity to form the innermost layer on the outermost layer. In the same manner as in Example 1, a bottle-shaped molded body was obtained. In this molded product, there was no mixed layer between the outermost layer and the innermost layer. The same measurement as above was performed on this molded body. Table 1 shows the results.

[0038]

[Table 1]

As is clear from the results shown in Table 1, the molded articles of the respective examples in which the innermost layer and the outermost layer were formed using the slurry containing pulp fibers having specific physical properties were the molded articles of the comparative examples. The occurrence of cracks and uneven thickness at the time of molding (parts having a thickness of 1/2 or less with respect to the average thickness of the molded article or parts having a thickness that can be visually distinguished by visual inspection) is prevented. Further, it can be seen that the surface smoothness is excellent. In particular, in the molded articles of Examples 1 to 4 in which the mixed layer is formed between the innermost layer and the outermost layer, compared to the molded article of Example 5,
The peel strength between the innermost layer and the outermost layer is high.

[0040]

According to the present invention, it is possible to obtain a multilayer pulp molded hollow molded article having a uniform thickness, no cracks during papermaking, and excellent transferability. In particular, in a hollow molded body having an opening, a body and a bottom, without forming a seam in the body, a smooth hollow molded body having a deep surface with a large depth,
It can be obtained with a uniform thickness and without generating cracks. Further, by forming the above-mentioned mixed layer between the innermost layer and the outermost layer, the delamination strength between both layers can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a multilayer structure of a molded article of the present invention.

FIG. 2 is a diagram showing an example of a fiber length frequency distribution of pulp fibers preferably used in the molded article of the present invention.

FIG. 3 is a process chart sequentially showing a paper making process in a process for producing a hollow pulp molded article of the present invention.

[Explanation of symbols]

 Reference Signs List 1 innermost layer 2 outermost layer 3 mixed layer 4 molded body 5 opening 6 trunk 7 bottom

[Procedure amendment]

[Submission date] August 3, 2000 (2000.8.3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

SUMMARY OF THE INVENTION The present invention relates to a multilayer pulp molded hollow molded article having an outermost layer and an innermost layer,
The innermost layer has a length-weighted average fiber length of 0.8 to 2.0 m.
m, 100 Canadian Standard Freeness
６００600 cc and a fiber length of 0.1 in the fiber length frequency distribution.
Fibers in the range of 4 mm or more and 1.4 mm or less are 20-
Fibers occupying 90% and in a range of more than 1.4 mm and 30 mm or less are formed using a slurry containing pulp fibers occupying 5 to 50% of the whole, and the outermost layer has a length-weighted average fiber length. 0.2-1.0 mm, Canadian Standard Freeness 50-600 cc, and pulp fibers in which the fiber length is 0.4 mm or more and 1.4 mm or less in the frequency distribution of the fiber, which accounts for 50-95% of the whole. is formed using a slurry containing, and the
The pulp fibers contained in the innermost layer and the pulp fibers contained in the outermost layer
The pulp fibers to be used are pulp with different physical properties.
It is obtained by achieving the above objects by providing a flop fibers der Ru multilayered pulp molded hollow product.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tokuo Tsuura 2606 Kabane-cho, Akaga-cho, Haga-gun, Tochigi Prefecture Inside Kao Co., Ltd. (72) Inventor Kenichi Otani 2606, Kaiga-cho, Akaba-cho, Haga-gun, Tochigi Prefecture Kao Co., Ltd. F Terms (reference) 3E033 AA01 BA01 BA10 BA14 BB02 BB04 BB08 CA03 CA20 DB01 DD01 FA10

Claims (4)

[Claims] 1. A multilayer pulp molded hollow molded article having an outermost layer and an innermost layer, wherein the innermost layer has a length-weighted average fiber length of 0.8 to 2.0 m.
m, 100 Canadian Standard Freeness
６００600 cc and a fiber length of 0.1 in the fiber length frequency distribution.
Fibers in the range of 4 mm or more and 1.4 mm or less are 20-
Fibers occupying 90% and ranging from more than 1.4 mm to 30 mm or less are formed using a slurry containing pulp fibers occupying 5 to 50% of the whole, and the outermost layer has a length-weighted average fiber length. 0.2-1.0m
m, Canadian Standard Freeness 50-6
00cc, fiber length 0.4m in frequency distribution of fiber length
m to 1.4 mm or less in the range of 50 to 95
% Of a multi-layer pulp molded hollow article formed using a slurry containing pulp fibers occupying 5% by weight. 2. The thickness of the innermost layer is 30 to 95 of the total thickness.
%. The multi-layer pulp molded hollow molded article according to claim 1, wherein 3. The multilayer according to claim 1, wherein a mixed layer whose composition continuously changes from the composition of the outermost layer to the composition of the innermost layer is formed between the outermost layer and the innermost layer. Pulp mold hollow molded body. 4. A cavity having a shape corresponding to the outer shape of the hollow molded body to be molded is formed by abutting a pair of papermaking split dies each having a plurality of communication holes communicating the outside and the inside. Into the cavity of the mold
The pulp molded article according to any one of claims 1 to 3, which is obtained by injecting a slurry for forming an outermost layer and then injecting a slurry for forming an innermost layer into the cavity.