JP2000272038A - Foamed sheet suitable for incineration treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed plastic sheet having higher combustibility than that of a conventional sheet. SOLUTION: In a foamed plastic sheet in which a plane plastic back film 2 is laminated on the lower surfaces of the projections of a plastic cap film 1 in which a lot of the projections are formed, and a large number of closed cells 3 are formed, 1-60 wt.% of a hydrous silicate 1-100 μm in particle diameter and zeolite powder 4 expressed by formula: WmZnO2n.sH2O (m, n and s are optional numbers) are added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a plastic foam sheet, and provides a plastic foam sheet suitable for disposal by incineration.

[0002]

2. Description of the Related Art A flat back film is adhered to the bottom surface of a projection of a cap film having a large number of projections, which is mainly made of polyolefin plastic as a main material, to form a large number of sealed air bubbles. BACKGROUND ART A plastic foam sheet or a foam sheet in which another flat liner film is bonded to the top of a projection of a cap film (hereinafter, these are collectively abbreviated as "bubble sheet") are used in the field of packaging and the like. Widely used. In particular, a relatively thin material using polyethylene as the main substance is known by the trade name "bubble wrap" and is frequently used as a packaging material, a cushioning material, and a heat insulating material. Thick hard materials using polyethylene and polypropylene as main raw materials are known under the trade name of "Purapearl",
It is widely used as a structural material and a core material.

[0003] This kind of bubble sheet can be reused several times depending on how it is used, but if it becomes dirty or bubbles are crushed, it must be discarded. The fact is that most of the waste is disposed of by incineration because it is bulky. Since plastics as a material of the foam sheet are mainly polyolefins such as polyethylene, those generated by combustion are limited to water and carbon dioxide, and it can be said that combustion exhaust gas is relatively clean. This point can be said to be somewhat advantageous when compared to the fact that so-called foamed plastic contains chlorofluorocarbons and hydrocarbons inside the cells, and there is a possibility that undesired components may be generated in the exhaust gas by combustion. In addition, since the content of the bubbles is air, which also assists the combustion of the bubble sheet as a source of oxygen, the bubble sheet is generally good in flammability, and the incineration process should not have much problem. .

[0004] However, the actual incineration is performed not only with the foam sheet alone but also with other things such as dust, so that the high flammability of the foam sheet is not always utilized as it is.

On the other hand, as a material of the garbage bag, a polyethylene film containing a large amount of calcium carbonate is used. This calcium carbonate aims to protect the incinerator by suppressing heat generation during incineration. However, in fact, it is unavoidable that the film becomes thicker due to the mixing of calcium carbonate, the amount of polyethylene to be incinerated increases, and not only the intended place is not realized, but also the residual ash from incineration increases. The problem has been pointed out.

An important problem with refuse incinerators is that they must be operated under conditions that produce as little poisonous dioxins as possible. There are more than 200 types of compounds collectively referred to as "dioxins", but what can be said in common is that they contain chlorine.

[0007]

SUMMARY OF THE INVENTION The basic object of the present invention is to provide a plastic foam sheet, which is originally rather suitable for incineration, which has a higher flammability than conventional products, and is therefore incompatible with dust and the like. It is an object of the present invention to provide a bubble sheet suitable for incineration treatment, in which incineration is easy even if it is performed and generation of dioxins in exhaust gas is reduced. A secondary object of the present invention is to provide a bubble sheet in which the cushioning effect of the bubbles is maintained and the above basic effects can be maintained.

[0008]

[Means for Solving the Problems]

[0009]

FIG.

[0010]

FIG. 2

The plastic foam sheet suitable for incineration according to the present invention is a plastic cap film (1) having a large number of projections, as shown in a plan view in FIG. 1 and a cross section in FIG. In a plastic foam sheet formed by bonding a flat plastic back film (2) to the bottom surface of the projection to form a number of closed air bubbles (3), a plastic having a particle system of 1 to 100 μm
, And 1 to 60% by weight of a powder (4) of hydrated silicate, commonly called "zeolite". Normal "zeolite" is the general formula _{W m Z n O 2n · sH} 2 O
(M, n, s are arbitrary numbers), and W is Na, Ca,
K, very rarely either Ba or Sr, and Z is Si
What is a mixture of Al and Al is well known.

[0012]

DETAILED DESCRIPTION OF THE INVENTION "Zeolite" used in the present invention
In the combustion process using an incinerator or the like, the following process is used in the combustion process to reduce and reduce the amount of diokin in exhaust gas to adsorb and fix hydrogen chloride. _{W m Z n O 2n · sH} 2 O + 4nHCl → W m Z n Cl
_4n · sH ₂ O + 2nH ₂ O Similarly, sulfur oxide also has the following adsorption and fixation effects. _{W m Z n O 2n · sH} 2 O + 2nSO 3 → W m Z n S n
Due to the antibacterial effect of O _3n · sH ₂ O + nO ₂ W ⁺ ions, it has an antibacterial function before incineration. In order to clearly obtain these effects, it is usually necessary to add “zeolite” to the foam sheet material such as polyethylene in an amount of 1% by weight or more, preferably 60% or more. The addition of a large amount is disadvantageous because the effect corresponding to the increase in cost is not obtained and the processability of the plastic is impaired. For this reason, an upper limit of 60% by weight, preferably 40% by weight, is provided. With the addition amount in this range, the bubble sheet can be manufactured without making any other changes to the conventional technology. The preferred range of the amount of "zeolite" to be added varies slightly depending on the physical properties of the plastic material to be used, the specifications of the foam sheet to be produced, especially the thickness of the film, etc. ４０40% by weight.

Various modes are possible for the plastic foam sheet of the present invention. For example, as a plastic material, 0.1 to 30% by weight of iron oxide, which has recently attracted attention as a combustion promoter, may be added. This is because the temperature at the time of combustion is increased by adding the iron oxide powder, and the efficiency of the adsorption and fixation of hydrogen chloride is increased.
Furthermore, in addition to "zeolite", one using 1 to 30% by weight of calcium carbonate powder is used.
This is one example. This calcium carbonate CaCO ₃ is decarbonated by combustion to form quicklime CaO, and has a function of fixing and removing acidic substances such as chlorine, hydrogen chloride, sulfur oxides, and nitrogen oxides in the combustion ash gas.

Another variation is to enclose oxygen-enriched air in a bubble. Needless to say, the oxygen in the bubbles participates in the combustion, and the combustion of the bubble sheet proceeds more intensely. Encapsulation of oxygen-enriched air in bubbles can be easily performed by replacing the atmosphere on the cap film surface with oxygen-enriched air when forming a cap film usually performed by vacuum forming.

[0015] The gas enclosed in the gas bubbles is exchanged between the inside and the outside with the film interposed between the inside and the outside of the film, if the plastic film constituting the gas bubbles is easily permeable to gas. As the proportion of oxygen in the air decreases, the bubbles collapse. By avoiding this, it is desired to secure the buffering capacity of the bubbles for a long period of time and to suppress the exchange of gas molecules as much as possible so that the high flammability is maintained during the incineration treatment. For this purpose, it is recommended to use a plastic film as a laminate of two or more layers, one of which has a gas barrier property. Nylon is preferable as a representative of the gas barrier plastic film, and it is recommended to use a film obtained by laminating conventional polyethylene with co-extrusion. Instead of the gas barrier layer, a plastic film having a surface coated with a paint containing mica powder may be used.

[0016]

EXAMPLE A low-density polyethylene kneaded with 30% by weight of "zeolite" was used as a material to produce a 2-layer polyethylene film foam sheet having an air chamber height of 4 mm and a diameter of 10 mm.

[0017]

[Incineration test] 50 g of the foam sheet of the example and 3.0 kg of household waste were mixed and incinerated in an electric furnace. The amount of hydrogen chloride generated at this time was 0.2 g. "Zeolite"
In a similar experiment using an air bubble sheet containing no.
Since 0 g of hydrogen chloride was generated, about 98% of the hydrogen chloride suppression prevention effect was confirmed.

[Antibacterial test] 3.0 kg of garbage was put into 50 g of the bubble sheet bag of the example, and the numbers of Escherichia coli and Staphylococcus aureus were measured after 24 hours. The numbers of Escherichia coli and Staphylococcus aureus generated at this time were 5.0 * 10 ₃ (cells / ml) and 1.0 * 10 ₂ (cells / ml). "Zeolite"
In the same kind of experiment using a bubble sheet containing no, 7.3 * 10 ₆ (cells / ml) and 6.5 * 10 _{4 respectively.}
(Cells / ml), 99.9% of Escherichia coli and 99.8% of S. aureus were confirmed to be antibacterial.

[0018]

The plastic foam sheet of the present invention
The effect of suppressing the hydrogen chloride and sulfur oxides of “zeolite” facilitates realizing incineration under conditions where the content of dioxins in exhaust gas is kept relatively low. Na,
It also has a high antibacterial effect by ions such as Ca and K.

The effect of improving the flammability can be further enhanced if the gas sealed in the bubbles is oxygen-enriched air, and the effect of this embodiment is to use a gas barrier material as the plastic film material. By doing so, it can be enjoyed for a long time. .

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of the plastic foam sheet of the present invention.

FIG. 2 is a sectional view taken along the line II of FIG. 1;

[Explanation of symbols]

 1 Cap film 2 Back film 3 Bubbles 4 Zeolite powder

Claims (3)

[Claims] 1. A plastic bubble sheet formed by bonding a flat plastic back film to a low surface of a projection of a plastic cap film provided with a large number of projections to form a number of closed air bubbles. hydrous silicates range of particle system 1 to 100 [mu] m, the general formula _{W m Z n O 2n · sH} 2 O (m, n, s is an arbitrary number) to no powder 1 called "zeolite" represented by 60 weight%
A plastic foam sheet characterized by being added. 2. The plastic foam sheet according to claim 1, wherein a polyolefin resin is used as the plastic material. 3. The above “zeolite”, wherein W is Na,
Any of Ca, K or Ba, Sr, and Z is Si
The plastic foam sheet according to claim 1, wherein the plastic foam sheet is a mixture of Al and Al.