JP2905693B2 - Shopping bag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shopping bag mainly used in supermarkets, various mass stores, retail stores and the like.

[0002]

2. Description of the Related Art Conventionally, in supermarkets, various mass retailers, and retail stores, it is common to print to a shopper corresponding to each shop or hand a colored bag (hereinafter referred to as a shopping bag) at a cash register. It was a target. Such shopping bags are not only useful when carrying goods, but also because they usually have a handbag, so they are convenient to carry and close the opening. Have been reused.

On the other hand, in recent years, changes in lifestyle, living standards,
Increasing income levels have created new products and rich material cultures, but the amount of garbage discharged from households has also increased rapidly, and the problem of garbage disposal has become a major social problem.

[0004] Of these wastes, combustible wastes are generally burned in black or blue plastic garbage bags in which various pigments are added to a thermoplastic resin represented by a polyethylene resin in an incinerator. The remaining ash and unburned residue after incineration are disposed of by landfill.

However, incineration of combustible waste has the following problems. That is, air pollution by NOx generated during combustion, lack of landfills to dispose of large amounts of residual ash and unburned residues after incineration, leakage of harmful components in residual ash at landfills, or harmful dioxin emissions In addition to problems such as generation, if combustible waste contains a large amount of high-calorie plastic waste or plastic garbage bags, incinerators may cause a rise in incinerator temperature. There was a problem such as breakage.

As a method for solving such a problem,
For example, a method of controlling NOx amount by burning under low oxygen concentration, a method of controlling the inside of the furnace to a certain temperature or less to prevent damage to the incinerator due to temperature rise, including harmful substances, such as burning while spraying water There has been proposed a method of insolubilizing remaining ash, solidifying the cement, and then landfilling. Furthermore, regarding plastic garbage bags that are incinerated together with combustible garbage, recently, translucent garbage bags containing a large amount of calcium carbonate have been required in place of conventional garbage bags to reduce garbage and burn calories. Some local governments are trying to reduce this. At the same time, each local government encourages supermarkets to adopt translucent and calcium carbonate-containing ones, as in the case of garbage bags, since there are very many opportunities for households to reuse shopping bags as garbage bags. Has been reported.

On the other hand, as an example in which iron oxide is contained in plastic, a method of dispersing ferromagnetic fine powder in a thermoplastic resin and separating plastic waste by the action of magnetism (Japanese Patent Laid-Open No. 52-68247). ) Or polyethylene,
A method of preventing malodor in a bag by incorporating titanium oxide, aluminum oxide, nickel oxide and iron oxide in polypropylene (Japanese Patent Laid-Open No. 3-212353) has been proposed.

[0008]

As described above, a shopping bag is originally intended for storing and transporting goods, and has a function as an advertising medium for a supermarket or various retail stores that provide the shopping bag. Therefore, there is a strong demand for excellent color tone and mechanical strength, inexpensiveness in addition to the use of no harmful substances, and the like. Therefore, it has been extremely difficult to provide a function considering the waste disposal problem while satisfying those requirements.

For example, when a large amount of calcium carbonate is contained in a thermoplastic resin, not only the appearance is poor, but also the mechanical strength is lowered, and the calcium carbonate powder adhering to the film adheres to clothing and goods. There was a problem that it was easy to do. Further, although this bag is effective in preventing damage to the incinerator due to high temperature, there is a problem that the amount of residual ash after incineration increases by an amount corresponding to the addition of calcium carbonate.

The method disclosed in Japanese Patent Application Laid-Open No. 52-68247 is for the purpose of recovering plastic by mixing and dispersing ferromagnetic fine powder such as magnetite in plastic to impart magnetism. In the method disclosed in Japanese Patent Application Laid-Open No. 3-212353, a gas-decomposing substance containing at least titanium oxide, aluminum oxide, nickel oxide, and iron oxide is contained in polyethylene or polypropylene constituting the bag, so that odors such as garbage in the bag can be obtained. The purpose is to prevent the problem.

Therefore, the present invention can provide various color tones excellent in aesthetic appearance, and is excellent in mechanical strength, safety, etc., and even when reused as a garbage bag, By incineration with combustible waste, combustion efficiency can be maintained even under low temperature and low oxygen concentration conditions, and the function of minimizing unburned residue, ash, and harmful substances after incineration is provided. A technical problem is to provide a shopping bag that has been completed.

[0012]

The above technical objects can be achieved by the present invention as described below. That is, the present invention relates to a shopping bag made of a thermoplastic resin film containing 0.1 to 20.0 wt% of a ferric oxide-containing particle or an iron oxide particle or a mixture of the particles, and the thermoplastic resin having a high density. A shopping bag characterized by being polyethylene or a linear low-density polyethylene, and a shopping bag characterized by the fact that the hydrous ferric oxide particles are spindle-shaped hydrous ferric oxide particles, and The shopping bag, wherein the iron oxide particles are granular magnetite particles having a surface water content of 0.02 wt% / m ² / g or more.

Next, various conditions for implementing the present invention will be described. The thermoplastic resin in the present invention can be used without any particular limitation as long as it is a thermoplastic resin suitable for ordinary extrusion molding. Low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ethylene and (meth)
Acrylic esters, polyethylene resins such as copolymers with other polymerizable monomers such as vinyl acetate can be suitably used because they are available in large quantities at low cost, and even when the thickness is relatively thin, mechanical High-density polyethylene and linear low-density polyethylene can be particularly preferably used in that a film having high strength can be obtained.

As the hydrous ferric oxide particles in the present invention, any of goethite (α-FeOOH) particles, lipid crocite (γ-FeOOH) particles, and δ-FeOOH particles can be used. The shape may be any of a spindle shape (bamboo leaf shape), a needle shape, a plate shape and the like, but a spindle-shaped hydrous ferric oxide particle is most preferable in terms of combustion efficiency.

According to observation with an electron microscope, the spindle-shaped hydrous ferric oxide particles are particles having an appearance in which a number of ultrafine fibers are bundled, and have a major axis diameter of 0.05 to 1.5 μm and an axial ratio. (Major axis diameter / short axis diameter-the same applies hereinafter) is 1 to 18, and the BET specific surface area is 30 to 250 m ² / g. Considering the combustion efficiency, the major axis diameter is 0.1 to 0.5 μm, the axial ratio is 3 to 15, and the BET specific surface area is 50 to 150 m ^2.
/ g is preferred. If the BET specific surface area is larger than 150 m ² / g, the kneadability with the thermoplastic resin will be poor.

The needle-shaped hydrous ferric oxide particles include not only needle-shaped particles but also needle-shaped particles having the appearance of dendrites appearing from some places.
2.0 μm, the axial ratio is 2 to 20, and the BET specific surface area is 10 to 200 m ² / g. Considering the combustion efficiency, the major axis diameter is 0.1 to 0.8 μm, the axial ratio is 5 to 15,
The BET specific surface area is preferably from 15 to 100 m ² / g.

According to electron microscopic observation, the plate-like hydrous ferric oxide particles have a hexagonal plate-like or disk-like appearance, and have a plate surface diameter of 0.02 to 1.5 μm and a plate-like shape. The ratio (plate diameter / thickness-the same applies hereinafter) is about 3 to 15.
Considering the combustion efficiency, the plate surface diameter is 0.03-0.5μ
m and the plate ratio are preferably 5 to 10.

The hydrous ferric oxide particles of these various shapes are:
Neutralization reaction between ferrous salt aqueous solution and alkali aqueous solution such as alkali hydroxide aqueous solution and alkali carbonate aqueous solution An oxygen-containing gas such as air is passed through a suspension containing precipitates in the presence or absence of additives. By doing so, it can be produced from an aqueous solution.

As the iron oxide particles in the present invention, hematite (α-Fe ₂ O ₃ ) particles, magnetite ( FeO ₂ )
_{x · Fe 2 O 3, 0} <x ≦ 1) particles, maghemite (gamma
-Fe ₂ O ₃₎ also can be used any particles,
The particle shape may be any of a spindle shape, a needle shape, a plate shape, and a spherical shape, an octahedron, a polyhedron, a so-called granular shape having an almost isotropic shape such as an amorphous shape, but the granular shape and the surface water content. Granular magnetite particles of 0.02 wt% / m ² / g or more are most preferable in terms of combustion efficiency.

Generally, the major axis diameter of the spindle-shaped iron oxide particles and the needle-shaped iron oxide particles is 0.03 to 1.0 μm, and the axial ratio is 2 to 12 μm.
And the BET specific surface area is 5 to 200 m ² / g. Considering the combustion efficiency, the major axis diameter is 0.05-0.3 μm,
The axial ratio is 3 to 10, and the BET specific surface area is 20 to 10.
0 m ² / g is preferred.

The average particle diameter of the normal iron oxide particles is 0.03 to 1.0 μm, but preferably 0.05 to 0.5 μm in consideration of combustion efficiency.

The spindle-shaped iron oxide particles and the needle-shaped iron oxide particles are obtained by mixing the spindle-shaped hydrated ferric oxide particles and the acicular hydrated ferric oxide particles obtained from the above-mentioned aqueous solution at 250 to 700 ° C in the air. By heating while maintaining the shape to form spindle-shaped hematite particles or acicular hematite particles, these hematite particles are then placed in a reducing atmosphere such as under a stream of hydrogen.
By heating while maintaining the particle shape at 0 to 500 ° C. to form spindle-shaped magnetite particles or acicular magnetite particles, these magnetite particles can be further converted to 200 to 500 ° C. in air.
It can be obtained by oxidizing while maintaining the particle shape at 500 ° C. to obtain spindle-shaped maghemite particles or acicular maghemite particles.

The plate-like iron oxide particles are prepared by heating a neutralized precipitate of an aqueous ferrous salt solution and an aqueous alkali solution in an autoclave to form plate-like hematite particles.
By heating the plate-like hematite particles in a reducing atmosphere such as under a stream of hydrogen at 300 to 500 ° C. while maintaining the particle shape to form plate-like magnetite particles, the plate-like magnetite particles are further reduced to 200 to 500 in air. It can be obtained by oxidizing into plate-like maghemite particles while maintaining the particle shape at ℃.

The granular iron oxide particles are formed by passing an oxygen-containing gas such as air into a suspension containing a precipitate obtained by neutralizing a ferrous salt aqueous solution with an aqueous alkali solution such as an aqueous alkali hydroxide solution and an aqueous alkali carbonate solution. By producing the granular magnetite particles by the
By heating the particles while maintaining the particle shape at ℃ to form granular maghemite particles, the maghemite particles or the previously obtained granular magnetite particles are further reduced to 500 to 90%.
It can be obtained by heating at 0 ° C. while maintaining the particle shape to obtain granular hematite particles.

The ferric oxide particles and the iron oxide particles include, for example, a ferric oxide particle having a yellowish-tan color,
Hematite particles are red-orange to reddish violet, magnetite particles are black to black-brown, maghemite particles are brownish, and yellow-containing ferric hydroxide oxide particles and black magnetite particles are mixed at an appropriate ratio. The powder has various colors such as a green color.

In the present invention, the type of the ferric hydroxide particles or the iron oxide particles is one or two selected from the ferric hydroxide particles and the iron oxide particles according to the desired color of the shopping bag. The above can be selected and used. Further, the content of the hydrous ferric oxide particles or the iron oxide particles to be contained in the thermoplastic resin or the content of the mixture is 0.1 to 20.0 w.
t%. If the amount is less than 0.1 wt%, the effect of improving the combustion efficiency is insufficient, and if it exceeds 20.0 wt%, the strength of the film is significantly reduced, which is not preferable as a shopping bag. Therefore, in consideration of improving the combustion efficiency of the entire combustible waste in the incinerator while maintaining the mechanical strength of the film, 0.5 to 10.0 w
t% is preferable, and more preferably 0.5 to 5.0 wt%.
It is. In addition, if the content is reduced, it becomes transparent or translucent, and conversely, if the content is increased, it becomes opaque,
The content can be appropriately selected from the above range according to the purpose.

In general, the shopping bag of the present invention is obtained by mixing a thermoplastic resin such as the above-mentioned polyethylene resin with the ferric oxide-containing particles or the iron oxide particles and supplying the mixture to a usual extruder.
After melt-kneading, a film having a thickness of about 10 to 70 μm can be formed by a method such as an inflation method or a T-die method, and heat-sealed in a predetermined shape to produce the film.

The thermoplastic resin film used in the shopping bag of the present invention may contain, if necessary, a conventionally known lubricant or anti-blocking agent, in addition to the ferric oxide particles or the iron oxide particles or the mixture of the particles. ,Antioxidant,
Various additives such as a weathering agent and a colorant may be appropriately blended, or various organic and inorganic fillers may be used in combination.

[0029]

First, the most important point in the present invention is that the ferric oxide particles or the iron oxide particles or the mixture of the particles have properties as a pigment capable of imparting various colors. , And a thermoplastic resin film containing them is provided with excellent combustion efficiency, and can reduce residual ash after incineration even under low temperature and low oxygen conditions.

The present inventor considers this fact as follows. Regarding the combustion mechanism in the present invention, first, iron atoms on the surfaces of the ferric oxide-containing particles and the iron oxide particles are stabilized by surface hydroxyl groups formed by dissociation and adsorption of water, but between the surface hydroxyl groups by heating in the combustion process. Dehydration occurs, producing coordinatively unsaturated iron and oxygen ions. Next, the coordinatively unsaturated active sites generated in this manner exhibit catalytic activity in a series of processes such as activation of oxygen by oxygen adsorption generated in the combustion process and dehydrogenation reaction from organic matter, and promote combustion. We think that we show effect.

In particular, when spindle-shaped hydrous ferric oxide particles or granular magnetite particles having a specific range of surface water content are used as the hydrous ferric oxide particles or iron oxide particles,
It is considered that the particles have excellent combustion efficiency because the number of iron-hydroxyl groups that can be activated per unit surface area by heating and dehydration on the particle surface is large. It is impossible to measure the surface water content because the spindle-shaped hydrous ferric oxide particles are dehydrated from between hydroxyl groups in the crystal structure in a temperature range of 150 to 350 ° C.

[0032]

The present invention will be described in detail below with reference to examples and comparative examples. In the following Examples and Comparative Examples, the combustion efficiency was evaluated based on the burning speed, the complete burning rate, and the low-temperature combustibility. The burning rate was determined by weighing 10 mg from a plastic shopping bag and raising the temperature at a rate of 10 ° C./min in air or at a low oxygen concentration (air / nitrogen = 1: 1) at 300 ml / min. The change in weight at that time was measured by a thermogravimetric analyzer (manufactured by Seiko Denshi Kogyo Co., Ltd.), and the time required from the time when the rapid weight loss started to the time when the rapid weight loss ended (combustion occurred during this time) It is presumed that it is.). Preferred values of the burning rate in the present invention are 3.5 minutes or less in air, 4.0 minutes or less under low oxygen concentration, particularly preferably 3.0 minutes or less in air,
It is 3.5 minutes or less under low oxygen concentration.

The complete combustion rate (it is considered that the larger the value is, the smaller the amount of unburned residue and ash after incineration is.) Is the weight converted to the combustible component at the time when the rapid weight reduction is completed in the above measurement. The reduction rate (%) was shown. The preferred value of the complete burn rate in the present invention is 90.
0 wt% or more, 88.0 wt% or more under low oxygen concentration, particularly preferably 93.0 wt% or more in air, and 90.0 wt% or more under low oxygen concentration.

The low-temperature flammability (which is considered to be a temperature necessary for the organic matter to be completely burned out) is indicated by the temperature at which no weight loss occurs in the above measurement. Preferred values of the low-temperature flammability in the present invention are 520 ° C. or less in air, 535 ° C. or less under low oxygen concentration, particularly preferably 490 ° C. or less in air, and 5% under low oxygen concentration.
20 ° C. or less.

The surface water content SW of the granular magnetite particles was determined by the Karl Fischer method moisture content (wt%) measured using a trace moisture analyzer AQ-6 (manufactured by Hiranuma Sangyo Co., Ltd.) under the following conditions. (M ² / g) (Equation 1).

[0036]

(Equation 1)

Examples 1 to 8 and Comparative Examples 1 to 5 Predetermined amounts of spindle-shaped goethite particles as ferric hydroxide particles, and magnetite particles, spindle-shaped hematite particles, and spindle-shaped maghemite particles as iron oxide particles in high-density polyethylene. After adding and mixing, a tubular film having a thickness of 30 μm was produced by an inflation extrusion molding method, and the bottom was heat-sealed to obtain a shopping bag. The properties are shown in Table 1. For comparison, a shopping bag made of only high-density polyethylene containing no ferric hydroxide particles or iron oxide particles at all (Comparative Example 1) and a commercially available bag made of high-density polyethylene containing titanium oxide were used. Shopping bag (Comparative Example 2), shopping bag made of high-density polyethylene containing 0.08 wt% of granular magnetite particles (Comparative Example 3), and high-density polyethylene containing 0.08 wt% of spindle-shaped goethite particles Shopping bag (Comparative Example 4), a shopping bag made of high-density polyethylene containing 0.08% by weight of spindle-shaped hematite particles (Comparative Example 5)
Was manufactured. The properties are shown in Table 1.

[0038]

[Table 1]

In Table 1, any of the shopping bags according to the examples is different from the shopping bags made of only the high-density polyethylene of Comparative Example 1 and the commercial shopping bags containing titanium oxide of Comparative Example 2. It can be seen that also in the case of, the amount of residual ash is reduced despite the extremely high combustion rate. Moreover, Examples 3 to 3 containing spindle-shaped goethite
The shopping bag No. 6 had a beautiful translucent yellow appearance because the content was small, and there was no problem in mechanical strength. On the other hand, the burning time of the commercially available shopping bag of Comparative Example 2 was extremely long, and there was a large amount of unburned residue at the end of burning. In addition, the content of the ferric oxide-containing particles or the iron oxide particles is set to 0.1.
The shopping bags of Comparative Examples 3 to 5 having less than 1 wt% had no effect of improving the combustion efficiency.

[0040]

The shopping bag of the present invention can control the color tone, transparency and the like by appropriately selecting the type and content of the hydrous ferric oxide particles or the iron oxide particles. Since it can be colored in a desired color in combination with a coloring agent, there is an advantage that a bag excellent in aesthetic appearance can be provided. Further, since the content is not so required, there is no danger of lowering the mechanical strength or soiling the clothing, and there is no problem in terms of safety at all.

Further, the shopping bag according to the present invention can be used as a garbage bag in ordinary households after it has been used for its intended purpose, and even when reused as a garbage bag, it contains hydrated ferric oxide particles or iron oxide particles that act as a combustion promoter. It has a low-temperature, low-oxygen concentration, which is effective for suppressing NOx and preventing damage to incinerators when it is incinerated together with combustible waste in incinerators. Even when the incinerator is operated under the condition, there is an effect that the combustible waste can be efficiently burned and the generation of unburned residue and residual ash can be reduced.
Further, if the content of the ferric oxide-containing particles or the iron oxide particles is increased, it is of course possible to reduce the calories burned in the same manner as in the case of a plastic garbage bag containing calcium carbonate.

Further, by the catalytic combustion action inherent in the ferric oxide-containing particles and the iron oxide particles, effects such as reduction of NOx amount and suppression of dioxin generation due to complete combustion of combustible waste (organic matter) can be expected. At the same time, ferric oxide particles and iron oxide particles react with the oxides of heavy metals during incineration to form ferrite and reduce the solubility of heavy metals in residual ash in water, thereby reducing the conventional insolubilization treatment. The effect can be expected.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nansei Horiishi 1-4 Meiji Shinkai 1-4, Otake City, Hiroshima Pref. Toda Kogyo Co., Ltd. (72) Inventor Satoshi Saito 1-4 Meiji Shinkai 1-4 Otake City, Hiroshima Pref. Toda Kogyo Co., Ltd. (72) Inventor Shigeo Yokoyama 4-1-2 Minami Funari, Naka-ku, Hiroshima-shi, Hiroshima Prefecture Toda Kogyo Co., Ltd. Creative Center Examiner Toshimasa Heijo (56) References JP-A-53-36538 (JP) JP-A-3-212353 (JP, A) JP-A-62-21530 (JP, A) JP-A-55-50055 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) A45C 3/04 B65D 30/02

Claims (4)

(57) [Claims] 1. A shopping bag comprising a thermoplastic resin film containing 0.1 to 20.0% by weight of hydrous ferric oxide particles or iron oxide particles or a mixture of said particles. 2. The shopping bag according to claim 1, wherein said thermoplastic resin is high-density polyethylene or linear low-density polyethylene. 3. The shopping bag according to claim 1, wherein the ferric oxide-containing particles are spindle-shaped ferric oxide-containing particles. 4. The iron oxide particles have a surface water content of 0.02 wt% / m ^2.
The shopping bag according to claim 1, wherein the bag is granular magnetite particles having a particle size of / g or more.