JPH0348054Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sheet-like packaging material, and more particularly to a sheet-like packaging material made of a corrugated resin foam sheet material useful for weighing and selling food products.

The packaging currently used for foodstuffs, etc. is divided into tangible packaging, which combines lightweight containers such as trays and containers with wraps and lids, and intangible packaging, which uses sheet-like materials such as paper, plastic films, sheets, and wood. It can be roughly divided into Tangible packaging has rapidly developed due to unmanned sales and rationalization of distribution, and one of its major functions is to stably hold and protect the packaged items, so packaging has become so large that it can be seen as excessive packaging. Costs also tend to be high. On the other hand, intangible packaging has been used for a long time for interpersonal sales, and although it lacks the ability to stably hold the packaged item, it is convenient as a simple packaging that is easy to package and low in cost.

The purpose of this invention is to take advantage of the ease, simplicity, and low cost of sheet-like packaging in intangible packaging, while adding the function of tangible packaging to stably hold the packaged item. The purpose is to provide packaging materials.

According to the present invention, the above object is to form a recess for receiving the packaged item at an appropriate location of a corrugated resin foam sheet material having a desired shape by vacuum forming or pressure forming, and to form a recess around the recess, etc. This is achieved by a sheet-like packaging material characterized by having crease lines.

Hereinafter, the sheet-like packaging material of the present invention will be described in more detail with reference to embodiments shown in the accompanying drawings.

In FIGS. 1 and 2, the sheet-like packaging material of the present invention has a corrugated resin foam sheet material 1 having a size that can wrap the packaged items, and has food items (for example, miso, The recess 2 for receiving packaged items such as side dishes, meat, fish, etc. has a structure formed by vacuum forming or pressure forming, which is a normal sheet plastic forming process. The shape, size, etc. of the recess 2 depend on the type and amount of items to be packaged,
The shape can be changed depending on the shape, etc., but generally it can take a square box shape, an ellipse, a circle, etc. as shown in Figure 2, and "d" in Figure 2.
The depth of the recess represented by is approximately 2 to 30 mm, preferably 5 to 15 mm.

Further, in the sheet-like package of the present invention, a fold line 3 is provided around the recess 2, and the sheet material portion 4 around the recess 2 of the sheet material 1 is folded toward the recess 2. It is possible and preferable to facilitate packaging of the packaged items placed on the package.
The crease line 3 can be created by pressing and heating with a press roller in the same way as "streaking" on thick paperboard, or depending on the material of the sheet material 1, it can be created by simply bending. can. In the illustrated embodiment, the crease line 3 is provided around the entire circumference of the recess 2, but depending on the case, some of the crease lines may be omitted, or a part of the crease line 3 may be cut. It may also be provided to make packaging easier.

Further, the width of the sheet material portion 4 around the recess that is bent toward the recess 2 is the width W ₁ , W ₂ or W ₄ of each sheet material portion 4 facing each other across the recess.
The following relationship exists between W ₅ and the width W ₃ or W ₆ sandwiched between the opposing sheet material portions of the recess: W ₁ +W ₂ ≧W ₃ or W ₄ +W ₅ ≧W ₆ 0< It is desirable that W ₁ , W ₂ ≦W ₃ or 0<W ₄ , W ₅ ≦W ₆ hold true. In addition, W ₁
When +W ₂ ≧W ₃ , W ₄ +W ₅ does not necessarily have to be greater than or equal to W ₆ . On the contrary W ₄
When +W ₅ ≧W ₆ , W ₁ +W ₂ is not necessarily W ₃
It does not need to be more than that, and it may also be omitted. Furthermore, even if either W ₁ or W ₂ or W ₄ or W ₅ is zero, as long as the above formula holds true, the sheet-like packaging material of the present invention can be constructed.

Furthermore, the corner portion of each sheet material portion 4,
That is, the hatched portion in FIG. 1 may be cut out as the case may be.

The corrugated resin foam sheet material constituting the sheet-like packaging material of the present invention is preferably made of a thermoplastic resin of 30 to 70%.
Filler based on weight% and inorganic solid fine powder 70 ~
Filled resin composition consisting of 30% by weight with foaming ratio of 3~
It is foamed 30 times, preferably 5 to 15 times, and formed into a corrugated sheet, and the actual thickness of the sheet is 0.05.
~1 mm, preferably within the range of 0.1-0.5 mm,
In addition, the height of the waves is 0.5 to 5 mm, preferably 0.5 to 3 mm.
It is desirable to be within the range of mm.

Such corrugated resin foam sheet materials are, for example,
The following method was previously developed by the inventors: () Thermoplastic resin powder (A) and the resin powder
Hydrophilic solid fine powder (B) that does not substantially melt at the melting temperature of the resin powder (A), which is partially embedded in the surface of (A) in an exposed state. Thermoplastic resin powder coated with (B)
A resin compound (C) consisting of the partially fused porous agglomerates of (A) is treated with an aqueous medium so that the porous agglomerates have at least 1 part by weight per 100 parts by weight of the resin compound (C). A resin compound that adheres to and retains an aqueous medium and is treated with the aqueous medium.
(C) is melt-kneaded in an extruder under pressurized conditions that substantially suppresses evaporation of the aqueous medium, and then () the melt-kneaded resin composition is passed through the extruder mouthpiece into a sheet or film. Japanese Patent Publication No. 13811/1983 (Patent Application No. 13811/1983) discloses that the method can be easily manufactured by a method consisting of discharging the product and then taking it off while limiting the width expansion ratio to about 1.5 times or less.
218721).

The thermoplastic resin used in the above method is not particularly limited, and any of those conventionally used in various plastic moldings can be used, such as high-density polyethylene, low-density polyethylene, polypropylene, polybutene, Olefin resins such as ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, and petroleum resins; Diene resins such as polybutadiene and polyisoprene; Vinyls such as polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, and polyvinyl alcohol Acrylic resins such as polymethyl methacrylate; Styrenic resins such as polystyrene, acrylic-styrene copolymers, acrylic-butadiene-styrene copolymers; Nylon-6, nylon-
Polyamide resins such as 66 and nylon-12; polyester resins such as polyethylene terephthalate are included. Each of these can be used alone, or two or more kinds can be used in a blend. However, from the standpoint of economy and ease of handling as packaging materials, olefin resins, vinyl resins, styrene resins, etc. are generally preferred, and are especially preferred because they produce noxious gases during combustion, soot, and odor. A small amount of olefin resin or the like is suitable.

On the other hand, the hydrophilic solid fine powder used in combination with the above resin is either hydrophilic itself or consists of an organic or inorganic substance imparted with hydrophilicity by a hydrophilic treatment.

Furthermore, the hydrophilic solid fine powder used in this method does not substantially dissolve at the melting temperature of the resin powder used in combination with the hydrophilic solid fine powder, and desirably may swell with an aqueous medium. be selected from those that do not dissolve easily. That is,
Solubility in water is generally less than 10g/at 25°,
Preferably less than 5 g/g is advantageously used.

Hydrophilic solid fine powders that can be suitably used include, for example, grain flours such as starch and wheat flour; plant powders such as wood flour; urea resins, melamine resins,
Hydrophilic resin powders such as phenolic resin; metal powders such as iron and aluminum; and inorganic powders such as talc, clay, calcium carbonate, silica, alumina, and glass powder. These solid fine powders have sufficient hydrophilicity by themselves, but in addition, these fine powders contain substances (hereinafter referred to as surfactants) that make the surface of these fine powders more susceptible to water. ), nonionic surfactants such as fatty acid alkanolamides, fatty acid monoglyceroids, polyethylene glycol fatty acid esters; fatty acid amides, fatty acid metal salts,
Anionic surfactants such as alkyl sulfate type and alkyl phosphate type; cationic surfactants such as ammonium salts; fatty acids; polyhydric alcohols such as polyethylene glycol, polypropylene glycol, and glycerin; ethers such as polyethylene glycol diethyl ether; By surface treating with polyvinyl alcohol or the like or a mixture thereof, it is possible to further increase the hydrophilicity and improve the affinity bond between the resin and the fine powder.

Furthermore, even if a substance is hydrophobic, it can be made hydrophilic by surface treatment with a surfactant such as those mentioned above, or a hydrophilic substance such as polyvinyl alcohol, fatty acids, polyhydric alcohols, or ethers. It can be used in the same manner as the hydrophilic substances described above.

The hydrophilic solid fine powders described above can be used alone or in combination of two or more. In particular, talc, calcium carbonate, clay, silica, and alumina having an average particle size of 1 to 15 microns are preferably used.

A portion of the above-mentioned hydrophilic solid fine powder, generally up to 20% by weight, preferably 10% by weight or less of the total amount of the solid fine powder used, may be added to, for example, pulp, cotton, silk, etc.
It can also be replaced by organic short fibers such as hemp, wool, synthetic fibers, and recycled fibers, or inorganic short fibers such as glass fibers, carbon fibers, and asbestos.
By using these short fibers in combination, the mechanical strength of the foam can be significantly improved.

The particle size of the hydrophilic solid fine powder used in this method is not strictly limited, and can be varied widely depending on the desired degree of foaming, the type of resin, the physical properties required of the foam, etc. However, it is generally appropriate that the average particle size is 100 microns or less, preferably in the range of 0.1 to 50 microns, and more preferably in the range of 0.5 to 30 microns. In addition, when using short fibers as described above, the fiber length is generally 10 mm or less, preferably 5 mm or less, and
The fiber diameter is generally less than 100 microns, preferably 1~
Preferably it is in the range of 50 microns.

From the thermoplastic resin and the hydrophilic solid fine powder described above, a thermoplastic resin powder coated with the hydrophilic solid fine powder (hereinafter sometimes referred to as "composite resin powder") is prepared. When doing so, it is important that the solid fine powder is attached and buried in an exposed state on the surface of the resin powder (however, of course, the resin powder also has the solid fine powder inside it). powder may be dispersed). The amount of solid fine powder adhered to and buried in the resin powder is determined by the fact that most of the surface of each resin powder is covered with the exposed solid fine powder, and the magnification is
It is desirable that the amount is such that when observed under a 300x electron microscope, the base of the resin powder is hardly visible.

Furthermore, it was found that a large number of the resin particles coated with the exposed hydrophilic solid fine powder aggregated, and the individual particles partially fused to each other to form a porous mass. is important. When such a porous aggregate is treated with an aqueous medium, it must be capable of stably adhering and retaining the aqueous medium, and therefore, the porous aggregate must have a water vapor adsorption rate of at least 0.05%, preferably 0.3%. It is highly desirable that this is the case.
Here, "water vapor adsorption rate" means that a porous aggregate of ₁ g of W after being kept in a constant temperature and humidity chamber at a temperature of 25 °C, a relative humidity of 30%, and a pressure of 1 atm for 24 hours is heated to a temperature of 105 °C,
After keeping it in a closed atmosphere with a water vapor pressure of 1.2 atm for 1 hour, take it out and leave it on paper for 3 minutes, then
When placed in a drying oven at 105°C for 3 minutes and immediately weighed, the amount is defined as W ₂ g, and the value is calculated using the following formula.

Water vapor adsorption rate (%) = W ₂ − W ₁ /W ₁ ×100 The size of the above porous aggregate is not important and can be any size, but it is easy to handle and melt-knead as described below. From the perspective of
A particle size range of 0.1 to 20 mm, preferably 0.3 to 5 mm is suitable. Therefore, if the particle size is larger than this, it is preferable to use a pulverizer, mixer, etc. to reduce the particle size to the above range.

One effective method for preparing such a porous aggregate is to mix the thermoplastic resin and hydrophilic solid fine powder described above in a high-speed (vortex) mixer, such as a Henschel mixer (manufactured by Mitsui Miike Manufacturing Co., Ltd.), a super This is a method of high-speed mixing at a temperature higher than the melting temperature of the thermoplastic resin in a mixer (manufactured by Kawada Seisakusho) or the like. This high-speed mixing generally begins at a point where the motor's rotational resistance fluctuates and increases from about 50 to about
It lasts for 250 seconds, preferably from about 70 to about 200 seconds, after which time the melt-mixed resin composition is discharged from the mixer. This results in a porous mass.

The ratio of the hydrophilic solid fine powder to the thermoplastic resin when charged into the above-mentioned mixing mixer depends on the type of resin and solid fine powder, the water absorption rate and water vapor adsorption rate required for the resulting porous aggregate, etc. Although it can vary widely depending on the situation, in general, the solid fine powder is used in an amount of 30 to 250 parts by weight, preferably 60 to 150 parts by weight, and more preferably 80 to 120 parts by weight per 100 parts by weight of the thermoplastic resin. They can be used alone or in a mixture of two or more. As mentioned above, when a part of the solid fine powder is replaced with a fibrous substance, it is appropriate that the fibrous substance accounts for 20% by weight or less, preferably 10% by weight or less of the total solid fine powder. .

In addition, when preparing the above-mentioned porous aggregate, in addition to the resin and solid fine powder, resin additives such as antioxidants, surfactants, colorants, ultraviolet absorbers, flame retardants, etc. may be added as necessary. . Examples of antioxidants that can be used include thiopropionic acid ester antioxidants such as dilauryl thiodipropionate; phenolic antioxidants such as alkylphenols and alkylbisphenols; or mixtures thereof. Examples of the surfactant include those mentioned above. The antioxidant is usually used as a solid fine powder in an amount of 0.01 to 5 parts by weight per 100 parts by weight, and the surfactant is used as a solid fine powder in an amount of 0.01 to 5 parts by weight per 100 parts by weight.
Generally, it can be blended in a proportion of 0.1 to 10 parts by weight per part by weight. In addition, examples of colorants include dyes and pigments such as cadmium red, chrome orange, chrome yellow, chrome green, cobalt aluminate blue, titania, phthalocyanine blue, and azo dyes, and examples of ultraviolet absorbers include salicylic acid, Examples include benzophenone-based and benzotriazole-based ultraviolet absorbers, and examples of flame retardants include phosphate esters, halogenated hydrocarbons, and antimony oxide, which have been conventionally used as resin additives in normal amounts. Can be blended.

The porous mass thus prepared is used as is as a resin compound and treated with an aqueous medium as blowing agent according to the method of the invention.

Water is generally used as the aqueous medium, which can be used to adjust the boiling point and vapor pressure of the medium, increase affinity for the porous aggregates, improve the dispersion stability of the aqueous medium during melt-kneading of resin compounds, and create bubbles. For the purpose of improving the uniformity of the water, surfactants, water-soluble polymers, polyhydric alcohols, water-miscible organic solvents, etc. can be appropriately added to the water. As the surfactant, those mentioned above can be used, and these are generally used in an amount of 0.1 to 50 g/, preferably 1 to 10 g/to water.
It can be added at a concentration of Examples of water-soluble polymers and polyhydric alcohols include polyvinyl alcohol with a degree of polymerization of about 500 to about 2000 and a degree of saponification of 85% or more, mono- or polyethylene glycol with a number average molecular weight of up to 400, glycerin, etc. are included, and these generally have a ratio of 1 to water.
It can be added at a concentration of ~100g/, preferably 10-50g/. Further, water-miscible organic solvents that can be used include, for example, alcohols such as methanol, ethanol, propanol, and cyclohexanol; esters such as ethyl acetate and butyl acetate; ethers such as diethyl ether, dioxane, and trioxane; acetone, and methyl ethyl ketone. and the like, and can be blended in a concentration of generally 1 to 100 g/, preferably 10 to 50 g/to water.

The amount of the above-mentioned aqueous medium used can be varied over a wide range depending on the desired expansion ratio of the foam, but in order to obtain a resin foam sheet with a beautiful wavy shape, it is necessary to It is important to use at least 1 part by weight of the aqueous medium per part to ensure a foaming ratio of 3 times or more. If the amount of the aqueous medium used is too small, foaming tends to become non-uniform and the bubbles tend to become unstable, which is not preferable. The upper limit of the amount of the aqueous medium used is not strictly limited, but generally 10 parts by weight or less per 100 parts by weight of the porous aggregate is sufficient, preferably 2 to 6 parts by weight, more preferably 2 to 6 parts by weight. It is appropriate to use within the range of 4 parts by weight so as to obtain a resin foam sheet with a foaming ratio of about 3 to about 30 times, particularly about 5 to about 15 times. Treatment of the resin compound with an aqueous medium can be carried out by combining the two together and mixing in a mixer.

The resin compound treated with the aqueous medium as described above is then melt-kneaded in an extruder under pressurized conditions in which evaporation of the aqueous medium is substantially suppressed. This melt-kneading can be performed in the same manner as melt-kneading during the production of ordinary resin foams, and as the extruder, for example, a non-vented single-screw extruder, a non-vented multi-screw extruder, etc. can be used. . Here, "pressurized conditions in which evaporation of the aqueous medium is substantially suppressed"
means a pressure condition higher than the vapor pressure of the aqueous medium impregnated into the resin compound at the melt-kneading temperature. The operation of the extruder is not particularly limited, and can be carried out in accordance with a known resin foam molding method.

The resin composition sufficiently melted and kneaded in the extruder is discharged from the die in the form of a sheet. Either T-die or circular die can be used as the cap, but generally T-die (flat cap) is used.
is more suitable. Further, the spacing between the lips of the cap can be freely changed depending on the thickness of the resin foam sheet of the product, but it is generally appropriate to adjust it within the range of 0.01 to 2 mm, preferably 0.2 to 0.8 mm.

Since the discharged molten resin sheet foams immediately after being released from the pressurized condition, the discharged sheet is immediately cooled to prevent bubble breakage. The discharged sheet can be cooled using an air knife, an air ring, a cooling fountain, a cooling water tank, etc. provided near the mouthpiece of the extruder.

When producing a resin foam sheet using an extruder, conventionally the extruded sheet is produced using a tenter.
Normally, the width is expanded at a rate corresponding to the foaming ratio, but this method uses a widening rate of approximately 1.5 times or less.
A major feature is that the width is preferably not widened (width ratio: about 1 times) and the width is taken almost as it is of the mouthpiece lip. By doing this, a resin foam sheet with neat waves in a direction perpendicular to the drawing direction can be obtained without using a specially shaped die.

In addition, in this specification, "widening ratio" refers to the width of the ejection opening of the die, for example, the lip width in the case of a T die, and the lip circumference length in the case of a circular die, when extruded. It refers to the width ratio of a resin foam sheet product, and is expressed by the following formula.

Width ratio = Width of extruded resin foam sheet or film product / Width of extruder mouthpiece Take-up ratio of extruded resin foam sheet, discharge speed of melt-kneaded resin composition, expansion ratio, required for product sheet Although it is necessary to adjust according to the film thickness, the shape of the waveform, etc., generally speaking, 1.5 times or more is required, and a range of 2 to 5 times is appropriate.
Here, the "take-up ratio" is expressed by the following formula: Take-up ratio = Actual take-up speed / Minimum take-up speed. This refers to the minimum speed that can be achieved.

The final wave shape, foaming ratio, and film thickness of the product's wavy resin sheet can be determined empirically by comprehensively adjusting the mouth lip interval, resin pressure, cooling power, take-up ratio, etc. In general,
A corrugated resin foam sheet can be obtained by reducing the gap between the mouth lips and lowering the temperature, extruding the molten resin composition by keeping the temperature as low as possible and increasing the resin pressure, and adjusting the take-up speed and cooling power to be large. The film thickness is thin, the corrugated shape is small, and the foaming ratio is small.On the other hand, the gap between the mouthpiece lips is made large and the temperature is made high, and the temperature of the molten resin composition is kept slightly high to slow down the take-up speed. If the thickness is adjusted in this direction, the resulting corrugated resin foam sheet will have a thick film thickness, a large corrugated shape, and a large expansion ratio. Moreover, it goes without saying that the expansion ratio can be adjusted by adjusting the amount of water added.

According to the method described above, a corrugated resin foam sheet can be easily produced using an ordinary extruder without requiring a specially shaped die, and furthermore,
Since an aqueous medium with a large latent heat of vaporization is used as a foaming agent, the range of temperatures at which foaming can be formed is widened, and extrusion foaming can be performed at relatively high temperatures.As a result, the corrugated shape of the resulting corrugated resin foam sheet is It becomes possible to change the shape, size, and/or expansion ratio over a wide range, and various excellent effects such as improving extrusion productivity can be achieved.

The method for producing the corrugated resin foam sheet material that can be used in the packaging material of the present invention is not limited to the method described above, but may also be produced by other known methods, such as producing a cap in a corrugated manner. It goes without saying that the ones that have been made can also be used in the same way.

The sheet-like packaging material of the present invention described above is based on a corrugated resin foam sheet, especially a corrugated resin foam sheet filled with inorganic solid fine powder, so even if the amount of resin used is small, it can be compared with It has extremely high rigidity, bulkiness due to corrugated foaming, excellent retention, protection ability, and cushioning ability for packaging of food and other packaged items, and is also low in cost, making it extremely useful for product distribution systems.

Furthermore, when manufacturing the sheet-like packaging material of the present invention, when the recesses are formed by vacuum forming, pressure forming, etc., since the base material is wavy, there is little chance of uneven thickness due to forming, and it can be used as a high-strength packaging material. material can be obtained.

Therefore, the packaging material of the present invention can be used for, for example, prepared foods,
It can be widely used in food products such as meat, fish, miso or vegetables; small metal fittings; wooden products; plastic products, etc.

Hereinafter, the production of the sheet-like packaging material of the present invention will be explained in more detail with reference to Examples.

Example 1 Blend amount (g) Resin: Polypropylene (Noblen manufactured by Mitsubishi Yuka Co., Ltd.
MA-8A: M1 = 0.7, density = 0.9) 10000 Fine powder: Talc (MS manufactured by Nippon Talc Co., Ltd.; average particle size 9μ) 10000 Surfactant: Fatty acid alkanolamide (Amizole LDE manufactured by Kawaken Fine Chemicals Co., Ltd.) 100 Fatty acid Monoglyceroid (Rikemar S-100 manufactured by Riken Vitamin Co., Ltd.) 50 Fatty acid amide (Alflo P- manufactured by Nippon Oil & Fats Co., Ltd.)
10) 50 Colorant: Titanium oxide (anatase type, A100 manufactured by Ishihara Sangyo Co., Ltd.) 500 Antioxidant: Dilaurylthiodipropionate 30 1,1,3-Tris(2-methyl-4-hydroxy-5-t- Butyl phenyl) butane 10 Using a high-speed mixing mixer (Kawada Seisakusho Super Mixer SMG100 mixing motor 22KW 4P/8P), the mixing tank (tank capacity 100) was heated by circulating heated oil at 140° to 150°C through the jacket. Ta. All of the above formulations were put into the mixing tank of the mixer and mixed at high speed.

After about 20 minutes, the mixing motor current began to fluctuate and increase (mixture temperature: 195°C), and after 80 seconds, it suddenly increased.
Since the temperature reached 80A (mixture temperature 210°C) in 40 seconds (total 120 seconds), the outlet was opened and the mixture was discharged.

The discharged mixture is rapidly cooled and coarsely crushed using a strong air-cooled field and low-speed rotating mixer to obtain a resin compound consisting of partially fused porous aggregates of resin powder coated with fine powder. Ta.

Next, a crusher (TC-3 type 3 manufactured by Morita Seisakusho)
Grind to a maximum particle size of 5 mm or less with
2.5 parts by weight of an aqueous medium was added to 500 c.c. of tap water containing 1% (100 parts by weight of resin compound) and mixed for 5 minutes or more to obtain a resin compound impregnated with an aqueous medium.

On the other hand, a coat hanger type T is attached to the 70mm extruder.
A die was attached, and an air knife was installed to blow air onto both sides of the sheet immediately after the die lip, so that the tip of the die lip and the discharged resin foam sheet could be cooled. The above resin compound was charged into this extruder, and the cylinder maximum temperature was 220℃, the resin temperature at the die inlet was 210℃, the resin pressure was 310Kg/cm ² , and the lip temperature was 180℃.
℃ and a lip gap of 0.3 mm, and the extruded sheet was taken off at a take-up magnification of 6 times without being widened, to obtain a corrugated resin foam sheet.

This corrugated resin foam sheet has a film thickness of 0.15mm, a corrugation height of 0.5~0.8mm, a corrugation width of 1.5~2mm, and a foaming ratio.
It was 7.5 times as hot.

Use a vacuum forming machine to form the above sheet into W ₃ = 80mm, W ₆ =
140mm, d=6mm size (see Figures 1 and 2)
Form the recesses and cut them into W ₁ and W ₂ = 70 mm, W ₄ and W ₅ = 20 mm (see Figures 1 and 2), and at the same time press a 3 mm wide bend line around the recesses. A sheet-like packaging material of a corrugated resin foam sheet was obtained by processing.

A piece of meat was placed in the recess of this package, W ₄ , W ₅ , then W ₁ , W ₂ were folded along the bending line and secured from the outside with a rubber ring.

This packaging material was easy to handle and the contents were stably retained.

Example 2 Blend (g) Resin: Low density polyethylene (Mitsubishi Kasei Novatec L F101A; MI=0.45, density=0.922)
9500 Ethylene-propylene rubber (manufactured by Mitsubishi Yuka Co., Ltd.)
Ep57p Mooney viscosity 88) 500 Solid fine powder: Talc (MS-1 manufactured by Nippon Talc Co., Ltd. Average particle size
9μ) 8000 Surfactant: Fatty acid alkanolamide (Amizole CDE manufactured by Kawaken Huain Chemical Co., Ltd.) 120 Polyethylene glycol (manufactured by Sanyo Chemical Co., Ltd.)
PEG6000) 60 Coloring agent: Titanium oxide (anatase type, A100 manufactured by Ishihara Sangyo Co., Ltd.) 300 Cobalt aluminate blue (manufactured by Dainichiseika Chemical Co., Ltd.)
0.1 Antioxidants: Dilauryl thiodipropionate 10 22'-methylenebis(4-methyl-6-tert-butylphenol) 20 Nonylphenyl phosphite 10 All formulations were prepared using the same high speed mixer as in Example 1. was added and mixed at high speed. After about 16 minutes, the mixing motor current started to fluctuate and increase slightly (mixture temperature: 190℃), and after 120 seconds, it suddenly increased and reached 50A (mixture temperature: 200℃) in 5 to 10 seconds (125 to 130 seconds in total). So I opened the outlet and released the mixture.

The discharged mixture is rapidly cooled and coarsely crushed by a low-speed rotating mixer with strong air cooling to obtain a resin compound consisting of partially fused porous aggregates of resin powder coated with fine powder. Ta.

Next, a crusher (TC-3 type 3 manufactured by Morita Seisakusho)
Grind to a maximum particle size of 5 mm or less, transfer to a mixer with a mixing rotation of 50 to 300 rpm, add an aqueous medium of 630 c.c. of tap water (3.5 parts by weight per 100 parts by weight of resin compound), and mix for 10 minutes. The resin compound was impregnated with an aqueous medium.

A T-die was attached to the 50 mm extruder, and air knives were installed on both sides of the die lip to cool the sheet discharged at the tip of the die lip. This extruder was charged with the above resin compound, cylinder maximum temperature 200℃, resin temperature at die inlet 190℃, resin pressure 220Kg/cm ² , lip temperature 170℃, lip gap.
The extruded sheet was operated at a width of 0.25 mm, and the extruded sheet was taken off at a take-up magnification of 8 times without widening, to obtain a corrugated resin foam sheet.

This corrugated resin foam sheet has a film thickness of 0.12 mm, a corrugated height of 0.4 to 0.7 mm, a corrugated width of 1 to 1.5 mm, and a foaming ratio of 11.
It was twice as hot.

The above sheet was formed using a vacuum forming machine to form W ₃ = 60mm, W ₆ =
120mm, d=5mm size (see Figures 1 and 2)
The recesses of W ₁ = 100mm, W ₂ = 40mm,
At the same time as cutting to W ₄ and W ₅ = 0 (see Figures 1 and 2), a 2 mm wide bending line was pressed around the concave area to create a sheet-like packaging material of the corrugated resin foam sheet. Ta.

A salad was placed in the recess of this packaging material, and W ₂ and W ₁ were folded along the folding line and secured from the outside with a rubber ring.

This package was easy to handle and the contents were stably retained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the sheet-like packaging material of the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. In the figure, 1... wavy resin foam sheet material, 2... recess, 3... crease line.

Claims (1)

[Scope of utility model registration request] A recess for receiving the packaged object is formed at an appropriate location on a corrugated resin foam sheet material having a desired shape and a thickness of 0.05 to 1 mm by vacuum forming or pressure forming, and folding is performed at an appropriate location around the recess. A flexible sheet-like packaging material that features a line of sight.