JPH1181200A - Production of molding product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a molding product, by which a molding product having a flexibility and a restoring force at the surface and in the interior, and further having a structural strength is produced without requiring many equipments and complicated process by coating a water dispersion containing an inorganic filter or an organic filler, which can be a modifying component, on one face of a low density pulp mold substrate. SOLUTION: A water dispersion containing an inorganic filler or an organic filler, which can be a modifying component, is coated on one face of a low density pulp mold substrate in an undried or dried state to provide the objective molding product in the method for producing the molding product. The dried density of the pulp mold substrate is preferably 0.08-0.25 g/cm<3> . The water dispersion containing the filler is preferably the one containing 1-6 wt.% binder based on the amount of the filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a molding formed from a cellulose pulp slurry and formed from a pulp molded product, which is used as a cushioning material for packaging.

[0002]

2. Description of the Related Art A pulp molded article using a cellulosic pulp slurry as a molding material is mainly used in newspapers, magazines, and the like.
Manufactured from waste paper such as cardboard and copy paper,
It has excellent properties such as excellent breathability and hygroscopicity, fixability and buffering property, and it has excellent properties such as recycling of used pulp mold and easy disposal of waste by incineration. For agricultural products, such as gift packages such as bottles and cans, or small household appliances,
It is widely used as a buffer and fixing material for mechanical parts.

[0003] However, the pulp molded article currently used has a hard surface and is rough and uneven, so that it is used as a tray for storing fruits and vegetables such as peaches, tomatoes, loquats and the like which are soft and easily damaged. In this case, there is a drawback that the fruits and vegetables are damaged due to the corners and irregularities of the surface of the tray during storage, and the surface of the tray and the fruits and vegetables are rubbed due to vibration during transportation, and the stored fruits and vegetables are damaged. Was.

In addition, the density of pulp molds is generally relatively high with an apparent density of 0.30 g / cm ³ or more and lacks in softness and lacks elasticity. It was not suitable.

[0005]

As a method of solving these drawbacks, a method of incorporating a softening agent into a pulp slurry (Japanese Patent No. 2573142) and a method of containing fine fibers (Japanese Patent Laid-Open No. 59-36800) No., JP-A-9-492
No. 00), a method of containing fine pieces of dry nonwoven fabric
No. -13300), aqueous adhesive and decomposition temperature of 100 ° C
A method of foaming by containing the following foaming agent (Japanese Patent Laid-Open No. 7-4)
1588), a method using hollow particles (Japanese Unexamined Patent Publication No. 3-12 / 1991).
No. 4895, Japanese Patent Publication No. 52-39924), a method of adding effervescent microcapsules (JP-A-5-230798).
JP-A-6-58155, JP-A-8-92898
No.), a method of adding a curled fiber (Japanese Unexamined Patent Publication No.
No. 41300) is provided as a method for producing a low-density molded article having low density and cushioning properties.

[0006] However, these low-density molded articles including pulp molds are rich in flexibility and elasticity, but are inferior in fixing property of inclusions due to insufficient structural strength.
Since the pulp molded article is easily damaged by the impact in the physical distribution process, the inclusion is often damaged. As a means for compensating for these disadvantages, a method of covering the surface of a pulp molded article with a resin film or the like (Japanese Patent Laid-Open No. 51-137571)
And Japanese Patent Application Laid-Open No. 3-49929), all of which contain synthetic resin products, and have problems in reuse after use and waste disposal.

A method of modifying a pulp mold for imparting strength to a low-density pulp molded article by a general method includes mixing a modifier such as a binder into a pulp slurry, Methods of spraying, showering, or curtain-coating the aqueous solution of the modifying agent on the surface are known, but in these methods, the modifying agent penetrates into the pulp molded article, and the molded article itself becomes hard.

In order to suppress the penetration of the aqueous solution of the modifier into the pulp molded article, it is conceivable to increase the concentration of the aqueous solution. However, in this case, it is difficult to uniformly apply the aqueous solution to the pulp molded article. .

[0009] As described above, in any of the methods, the contradictory properties such as the structural strength of the molded article as the cushioning fixing material and the flexibility and elasticity required for the protection of the inclusion are used to make the used molded article inconsistent. It cannot be solved including processing problems.

[0010] An object of the present invention is to provide a method for producing a molded molded article having a soft surface and an inner part which is resilient and has structural strength, without requiring many facilities and complicated steps.

[0011]

According to the present invention, there is provided a method for producing a molded molded article, comprising the steps of: providing an inorganic filler or an organic filler as a modifying component on one surface of a low-density pulp mold substrate in an undried or dried state; It is characterized by applying an aqueous dispersion containing the same.

The molded article produced by this method is soft and resilient due to the low density of the pulp mold base, and water containing an inorganic or organic filler as a modifying component is provided on one surface of the pulp mold base. By applying the dispersion, the modifying component is laminated on the surface of the pulp mold substrate, so that the structural strength of the pulp mold substrate is reinforced, and one surface and the inner surface are soft and resilient, and have structural strength. A molding is obtained.

[0013] In the above pulp mold base, it may be the dry density ^{0.08g / cm 3 ~0.25g / cm 3} .

The dry density of the pulp mold substrate is 0.08
With ^{g / cm 3 ~0.25g / cm 3} , molding the molded body with softness and resiliency desired as a buffer fixing material is obtained.

The aqueous dispersion containing the filler preferably contains 1 to 6% by weight of the binder with respect to the filler.

The binder contained in the aqueous dispersion serves to fix the modifying component layer formed on the pulp mold substrate surface to the pulp mold substrate when the aqueous dispersion is applied to the pulp mold substrate.

The application of the aqueous dispersion may be performed by spraying, showering, or curtain coating.

[0018]

FIG. 1 is a cross-sectional view showing an example of a molded article manufactured according to the present invention, and an example of an embodiment of a method of manufacturing a molded article according to the present invention will be described with reference to FIG. .

The method for producing a molded molded article according to the present invention is characterized in that water containing an inorganic or organic filler as a modifying component is provided on one side (convex side) of a low-density pulp mold substrate 1 in an undried or dry state. A molding 3 is obtained by applying the dispersion and laminating 2 the modifying component phase.

The pulp mold substrate 1 is manufactured by a known method using a cellulose pulp slurry raw material. This pulp mold substrate 1 has a dry density of 0.1.
It is manufactured to be from 08 g / cm ^{3 to} 0.25 g / cm ³ . Such a density is recognized as a suitable density for obtaining softness and resilience desired as a buffer fixing material. The above density can be obtained by adjusting the amount of the softener used for the cellulose pulp and the suction pressure at the time of molding. As the softening agent, an agent usually used for giving a soft feeling to a knitted fabric, a nonwoven fabric, a tissue or the like, for example, a surfactant, a wax emulsion or the like is used.

[0021] As described above, by the dry density of the pulp mold base 1 and ^{0.08g / cm 3 ~0.25g / cm 3} , pulp mold base 1 with a flexible and resilient as a buffer fixing member Is obtained. Although the flexibility and the density of the pulp mold substrate 1 are almost inversely proportional, the density is 0.08
If it is less than g / cm ³ , the releasability of the pulp mold substrate 1 from the mold during the molding process will be poor, and if it is more than 0.25 g / cm ³ , the pulp mold substrate 1 will have poor flexibility.

Next, on the convex side of the pulp mold substrate 1 in the undried state or the dried state produced as described above,
An aqueous dispersion containing an inorganic filler or an organic filler as a modifying component, and further containing 1 to 6% by weight of a binder with respect to the filler is sprayed, showered, or curtain-coated.

When this aqueous dispersion is applied to the pulp mold substrate 1, the modifying components contained in the aqueous dispersion remain on the surface to form a modifying component layer 2, which is also made of water. The binder contained in the dispersion liquid securely adheres to the surface of the pulp mold substrate 1. The modified component layer 2 formed and fixed on the surface of the pulp mold base 1 reinforces the structural strength of the flexible pulp mold base 1.

The inorganic filler used as the modifying component includes calcium carbonate, calcium sulfate, aluminum hydroxide, talc, mica (mica), hollow glass spheres,
There are carbon fibers, glass fibers, and the like. As the organic filler, general fillers such as vegetable fibers represented by wood pulp fibers, synthetic fibers, and starch particles are used.

The concentration of these fillers in an aqueous dispersion is suitably from 10% by weight to 60% by weight. If it is less than 10% by weight, it is difficult to increase the structural strength, and if it is more than 60% by weight, the water dispersibility becomes very poor.

As the binder, a water-soluble binder and an emulsion binder are used. Typical examples thereof include starch, polyvinyl alcohol (PVA), cellulose resin, amino resin, polyacrylamide resin, and polyethylene imine resin. , An acrylic emulsion, a vinyl acetate emulsion and the like are preferable in consideration of environmental suitability.

The optimum concentration of the binder used is 1 to 6% by weight based on the filler. If the content is less than 1% by weight, it is difficult to fix the filler on the mold base, and if the content is more than 6% by weight, the fixation is sufficient, but the binder penetrates into the inside of the surface of the mold base and loses the flexibility of the molding. become.

[0028]

【Example】

[Example 1] In a 1% by weight pulp slurry obtained by deinking an office waste paper, a commercially available paper softener (fatty acid polyamidoamine activator equivalent to 2.0% by weight of the pulp) (Bivol P Liquid Bayer K.K.) was added to prepare a pulp mold substrate forming material.

A pulp mold hand-making machine for testing equipped with a hand-making mold having a height of 300 mm, a width of 450 mm and a depth of 70 mm having three vertical and four horizontal lower hemispherical concave portions was prepared. After stirring, the water-absorbing valve of the hand-making machine was opened and suction was performed at a reduced pressure of 650 mmHg for 3 minutes to dehydrate. Next, a pulp deposit (dry density 0.09 g / cm ³ , dry amount 140 g / piece) was released from the mold.

Next, potato starch particles (average particle size: 47 μm) as a filler were prepared at 35% by weight, and rice starch as a binder was separately prepared on the convex side of the undried pulp mold substrate after release from the potato starch particles. By shaking the aqueous dispersion containing 15% by weight for 15 seconds, a molded molded article in which potato starch particles were laminated as a filler was obtained.

[Examples 2 to 5] In the same manner as in Example 1 except that the types of fillers were rice starch particles, cellulose floc, calcium carbonate, and hollow glass particles, moldings were obtained in which various fillers were laminated.

Comparative Example 1 A dry density of 0.09 g / cm ^{3 was obtained in the same} manner as in Example 1 except that the step of showering an aqueous dispersion containing potato starch particles as a filler was omitted. Thus, a pulp molded article having a dry amount of 200 g / piece was obtained.

Comparative Example 2 A pulp molded article having a dry density of 0.32 g / cm ³ and a dry amount of 185 g / piece was obtained in Example 1 without using a softener.

[Test] The moldings obtained in Examples 1 to 5 and Comparative Examples 1 and 2 are placed in a cardboard box, and peaches are arranged in the concave portions of the moldings. Five boxes (12 pieces / box) were prepared for each transport paper box. The peaches packed in these paper boxes were transported by truck from Isawa-cho, Yamanashi Prefecture to Shinjuku-ku, Tokyo, and then opened. The condition of the scratches on the peach surface was visually evaluated.

Table 1 shows the physical properties and experimental results of the moldings obtained in Examples 1 to 5 and Comparative Examples 1 and 2.
Shown in

Table 1 * 1 ◎ indicates that the texture of the surface layer feels very soft, ○ indicates that the texture of the surface layer feels soft, and x indicates that the texture is hard and rough.

* 2 Tensilon (manufactured by Orientec,
The compression energy per unit when the compact was compressed by 20 mm at a compression speed of 25 mm / min by OTM-1) was determined, and the result was defined as the compressive strength of the compact. The unit is kgf / cm ² * 3. The presence or absence of damage is indicated by the number of damaged peaches.

[0038]

As described above, according to the method for manufacturing a molded article according to the present invention, a molded article which realizes the contradictory properties such as flexibility, elasticity and structural strength desired as a buffer fixing material can be obtained. It can be manufactured without the need for many facilities and complicated processes. Further, since waste paper is used as a raw material, it is an effective means of recycling even for the problem of waste disposal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a molded molded article manufactured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pulp mold base 2 Modification component layer 3 Molding molded object

Claims (3)

[Claims] 1. A method for producing a molding, comprising applying an aqueous dispersion containing an inorganic filler or an organic filler as a modifying component to one surface of a low-density pulp mold substrate in an undried or dried state. 2. A method for producing a molding molded article according to claim 1, 0.08g / cm ³ ~0.25g / cm ³ dry density of the pulp mold base. 3. The method according to claim 1, wherein the filler-containing aqueous dispersion contains 1 to 6% by weight of a binder with respect to the filler.