JPH09324400A - Packaging material of pulp mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a packaging material of pulp mold capable of reducing flaw and shock in transporting process, excellent in retaining property and useful for vegetables and fruits, etc., by mixing a synthetic resin emulsion with unfoamed microcapsule type foaming agent and applying the mixture to a pulp mold and foaming the foaming agent. SOLUTION: This packaging material of pulp mold is obtained by mixing a synthetic resin emulsion such as ethylene-vinyl acetate emulsion with unfoamed microcapsule type foaming agent (used in preferably 1-60% solid content weight ratio based on mixed emulsion), applying the mixture to a pulp mold 1 before drying (preferably 100-400g/m<2> based on weight of solid content) and foaming the microcapsule type foaming agent by heating in drying process. Furthermore, the synthetic resin compound in the mixed emulsion has preferably tackiness after drying.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pulp mold which uses a pulp slurry as a forming raw material and is used as a cushioning material for packaging fruits and vegetables and industrial products.

[0002]

Prior art pulp molds have a consistency of 0.
A pulp slurry composed of 5 to 1.5% of cellulose fibers or the like is made in a paper making mold having irregularities, transferred to a take-up mold, then moved to a conveyor and dried in a drying process to produce. Therefore, the material of the pulp mold is a single-layer pulp, the surface of which is cellulose fiber, and the surface is harder than the synthetic resin foam cushioning material such as Styrofoam, and the surface of fruits and vegetables is damaged during transportation of fruits and vegetables. In the problem of getting stuck, and in the transportation of industrial products such as home appliances,
There was a problem with poor buffering.

In order to solve these problems, Japanese Unexamined Patent Publication No. 6-
In 322700, softening the surface of the pulp mold by adding a softening agent to the pulp, and in JP-A-5-51474, it is disclosed that the surface of the pulp mold is softened. There is a problem that the entire pulp mold becomes soft and the holding property as a packaging material is poor.

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, the holding property as a packaging material is the same as that of the one-layer pulp mold of the prior art, and the surface or a part of the surface is made as soft as expanded polystyrene. It reduces scratches and impact in the transportation process of fruits and vegetables and industrial products.

[0005]

That is, the invention according to claim 1 is a pulp mold packaging material having a foam layer on the surface of a pulp mold, wherein the foam layer is a synthetic resin compound as a binder component and foam. The present invention relates to a pulp mold packaging material comprising a microcapsule type foaming agent in the state. The invention according to claim 2 relates to a pulp mold packaging material in which the foam layer is partially present on the pulp mold surface.

According to a third aspect of the present invention, a synthetic resin emulsion and an unfoamed microcapsule type foaming agent are mixed and applied to a pulp mold before drying, and heated in a drying step to foam the microcapsule type foaming agent. The present invention relates to a method for producing a pulp mold packaging material. The invention according to claim 4 relates to a method for producing a pulp mold packaging material in which the solid content weight ratio of the microcapsule type foaming agent in the mixed emulsion is 1 to 60%. The invention as set forth in claim 5 relates to a method for producing a pulp mold packaging material in which a synthetic resin compound in a mixed emulsion has tackiness after drying.

The present invention uses the same pulp slurry as in the one-layer papermaking pulp mold in order to make the holding property as a packaging material similar to that of the conventional one-layer papermaking pulp mold. Before the post-drying step, in the step where the water content of the mold is 50 to 80%, the mixed emulsion of the synthetic resin compound and the unfoamed microcapsule type foaming agent is applied to the inner surface of the mold, and after partially penetrating, drying. In the process, the mold is dried and at the same time, the microcapsule type foaming agent is foamed to soften the mixed emulsion application part as much as Styrofoam, thereby reducing scratches and impact in the transportation process of fruits and vegetables and industrial products.

If the mixed emulsion of the present invention is applied to the entire surface of the pulp mold, the effect of preventing scratches of fruits and vegetables will be very good, but the cost will be high. Therefore, in the case of a packaging material for fruits and vegetables, it is efficient to apply it only to the surface of the mold that comes into contact with the fruits and vegetables. Further, the scratches of fruits and vegetables are also generated by the rotation of fruits and vegetables during transportation. Therefore, in order to prevent the rotation of fruits and vegetables, if a resin having adhesiveness is used as the synthetic resin compound, the occurrence of scratches is further reduced. In the case of a packaging material for industrial products, it is efficient to apply it only to the part that most absorbs the impact value generated by dropping or the like.

Therefore, the foamed layer may be formed on the entire surface of the pulp mold, or in the form of spots, grids,
It may be partially formed to have a stripe shape or the like. Further, the foam layer can be formed on both surfaces inside or outside the mold. When it is provided inside, it has a remarkable effect directly on the protection of the contents, and when it is provided outside the mold, it has a buffering effect between the outer box that houses the mold and the mold, resulting in the protection of the contents. can do.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION For the pulp mold used in the present invention, virgin pulp, waste paper pulp, etc. made from plant fibers such as wood fibers that are usually used are used, but glass is used depending on the required quality. Mixing inorganic fibers such as fibers, synthetic pulp, etc. is not hindered.

As the synthetic resin compound which is the binder component used in the present invention, an emulsion of acrylic resin, styrene-butadiene resin, vinyl resin, ethylene-vinyl acetate resin or the like is used. The microcapsule type foaming agent used in the present invention includes, for example, vinylidene chloride, acrylonitrile, vinyl chloride, acrylic acid ester, methacrylic acid ester, styrene and vinyl acetate resin as the skin component, and ethane and ethylene as the inclusion components. , Hydrocarbons such as propane, butane, isobutane and butene, and alkylsilanes such as tetramethylsilane and trimethylethylsilane. Of these, microcapsules obtained by coating butane gas with polyvinylidene chloride are preferable.

Regarding the solid content weight ratio of the synthetic resin compound and the microcapsule foaming agent, the ratio of the microcapsule foaming agent in the mixed emulsion is preferably 1 to 60%, preferably 2
0 to 40%. If the ratio of the foaming agent is less than 1%, the foaming ratio is too low and the softness is not sufficient as compared with styrofoam. On the other hand, if the ratio of the foaming agent exceeds 60%, the foaming agent is not retained on the mold surface due to lack of the adhesive component.

Further, the coating amount of the mixed emulsion on the mold surface is 100 to 400 g / m ² per solid content weight.
Is preferable, and when this is heated at a temperature of 80 to 120 ° C. for 10 to 60 minutes in the drying step, the foaming agent foams to form a foamed synthetic resin layer having a thickness of 1 to 5 mm on the coating surface of the mold surface,
This is useful for preventing scratches on fruits and vegetables during transportation and for improving buffering property when packaging industrial products.

In the present invention, the means for providing the foam layer on the surface of the pulp mold is a method of applying the mixed emulsion to the pulp mold. In the present invention, the application includes not only ordinary application but also spraying and the like. The foaming agent can be applied by a coating means such as printing, a roll coater, a curtain coater, or spray coating.

FIG. 1 is a sectional view of a pulp mold packaging material according to the present invention. In the figure, 1 is a pulp mold, 2 is a foam layer, and 3 is a content. By providing the foam layer 2 on the inner surface of the mold 1 at several places, the contents 3 are slightly lifted from the mold, and it is possible to avoid direct contact with the pulp mold having a relatively hard surface. Further, particularly when an adhesive synthetic resin compound is used, the contents can be prevented from rotating or moving during transportation, and the commercial value can be maintained. The effect of preventing the movement of the contents is particularly remarkable in the packaging of fruits and vegetables.

FIG. 2 is a perspective view of another embodiment of the pulp mold packaging material according to the present invention. FIG. 3 is a sectional view of a pulp mold packaging material of still another embodiment according to the present invention. These molds have a skirt to provide additional cushioning.

Examples will be described below.

Example 1 A papermaking mold of 6 pieces of melon made of wire mesh in 1% liquid of waste paper pulp (length = 430 mm, width = 325 mm, depth =)
84 mm, the number of holes = 6), and the pulp is adsorbed on the surface of the wire mesh by suction. Next, after transferring the pulp to the take-up mold, the pulp is placed on the conveyor. (The pulp moisture at this time is about 7
Next, ethylene-vinyl acetate emulsion (Hoechst synthesis, 1
84E) 100 parts (in solid content) and 30 parts of a microcapsule type foaming agent (F1300 manufactured by Matsumoto Yushi Co., Ltd .; polyvinylidene chloride for skin component, butane gas for inclusion) are mixed and stirred to prepare a mixed emulsion. Next, this mixed emulsion is applied to the surface of the contact hole with six melons in one mold of the pulp mold on the above-mentioned conveyer, three places in each hole. Next, this mold is dried in a drying process at 120 to 180 ° C. for 10 to 60 minutes to remove water from the mold to 4 to
The mixed emulsion is foamed at the same time as 9% to form a foamed layer having a thickness of 1 to 5 mm on the surface of the mold. (See FIG. 2) Six melons were put in this pulp mold, and then they were packaged in a corrugated board and transported by truck from Kumamoto to Tokyo, and the scratches on the surface of the melon after transportation were examined. The results are shown in Table 1.

Comparative Example 1 A pulp mold was prepared in the same manner as in Example 1 except that the foam layer was not formed, and the same test as in Example 1 was conducted. The water content of the mold was 4-9%. The results are shown in Table 1.

[0020]

[Table 1]

* 1) Evaluation criteria for the occurrence of scratches during transportation: 0 to 2 out of 6 melons are marked ○, 3 to 4 are marked Δ, 5 to 5
6 scratches are marked with x.

Example 2 A wire mesh mold making machine was put in a 1% liquid of waste paper pulp, and the pulp was adsorbed on the surface of the wire mesh by suction, and after passing through a take-up mold, it was placed on the belt conveyor on the outer periphery of FIG. Pulp mold with skirt (inner dimension 150 * 200 * 100
mm, the outer dimensions of the skirt are 200 * 250 * 103 mm). (The water content at this time is about 70%.) Next, a mixed emulsion similar to that of Example 1 was prepared, and this was mixed between the skirt portion and the body portion (outside of the mold) of the mold in FIG.
After coating on the spot, it is dried by heating to form a foamed layer having a thickness of 1 to 5 mm. (Refer to FIG. 3) The G value of this mold when dropped was measured. The results are shown in Table 1.

Comparative Example 2 A wire mesh mold making mold was put in a 1% liquid of waste paper pulp, and the pulp was adsorbed on the wire mesh surface by suction, and after passing through a take-up mold, the size of FIG. Place the pulp mold. (The water content at this time is about 70%.) Next, the mold is dried in a heating and drying step to give a water content of 4 to
A 9% mold was used and the same test as in Example 2 was performed. Table 2 shows the results.

[0024]

[Table 2]

* 2) G value when dropped: Dimension 147 * 196
The contents of * 98 mm are put into the mold of Example 2 or Comparative Example 2 and then packed with corrugated cardboard having an inner size of 205 * 253 * 107 mm. Next, this case is dropped from the height of 80 cm with the falling surface of FIG. 3 facing down, and the G value is measured.

[0026]

EFFECTS OF THE INVENTION According to the present invention, the holding property as a packaging material is the same as that of the one-layer pulp pulp mold of the prior art, and the surface or a part of the surface thereof is made as soft as styrofoam, so that fruits and vegetables can be produced. It was possible to reduce scratches and impacts during the product transportation process.

[Brief description of drawings]

FIG. 1 is a sectional view of a pulp mold packaging material according to the present invention.

FIG. 2 is a perspective view of the pulp mold packaging material of Example 1 of the present invention.

FIG. 3 is a sectional view of a pulp mold packaging material of Example 2 of the present invention.

[Explanation of symbols]

 1 Pulp mold 2 Foam layer 3 Contents 4 Outer box 5 Body 6 Skirt

Claims (5)

[Claims] 1. A pulp mold packaging material having a foam layer on the surface of a pulp mold, wherein the foam layer comprises a synthetic resin compound as a binder component and a microcapsule type foaming agent in a foamed state. 2. The pulp mold packaging material according to claim 1, wherein the foam layer is partially present on the surface of the pulp mold. 3. The method according to claim 1, wherein the synthetic resin emulsion and the unfoamed microcapsule type foaming agent are mixed and applied to the pulp mold before drying, and the microcapsule type foaming agent is foamed by heating in the drying step. A method for producing the described pulp mold packaging material. 4. The method for producing a pulp mold packaging material according to claim 3, wherein the solid content weight ratio of the microcapsule type foaming agent in the mixed emulsion is 1 to 60%. 5. The method for producing a pulp mold packaging material according to claim 3, wherein the synthetic resin compound in the mixed emulsion has tackiness after drying.