JPS6021650B2 - Carbon dioxide absorption sheet - Google Patents

Description

[Detailed description of the invention] The present invention relates to a carbon dioxide absorbing sheet.

Roasted coffee beans are generally sold in vacuum packaging, but since roasted coffee beans generate gas during storage, the shape of the vacuum package may collapse due to the generated gas.
As a result, although the quality of the packaged object does not deteriorate, the commercial value of the package may be reduced or lost.

In order to overcome this drawback, we have developed a vacuum cleaner in which a shape-retaining hollow body with ventilation holes is housed in a packaging container made of a transparent packaging material that houses a gas-releasing article such as roasted coffee beans. A packaging body was devised (see Utility Model Publication No. 53-36297). However, the vacuum packaging body according to this invention has the disadvantage that an extra space is required for the shape-retaining hollow body in order to accommodate the packaged object.

In addition, in the case of fruits and vegetables, since the fruits and vegetables themselves breathe, if they are sealed in sealed packaging, the freshness of the fruits and vegetables may be impaired by the carbon dioxide gas generated.

As a result of research to solve the above-mentioned drawbacks, the present invention has developed an inorganic water-retaining agent that can contain calcium hydroxide and water of crystallization in a thermoplastic resin, or an organic water-retaining agent whose structure does not change even when it contains water. A sheet-like material obtained by forming the blend into a sheet-like material exhibits carbon dioxide absorbing ability, and this sheet-like material is sealed together with the contents in a bag, or a bag is made from the sheet-like material and the bag is sealed. It was discovered that the above-mentioned drawbacks could be solved by sealing the contents inside the container, and the product was completed based on this knowledge. This carbon dioxide absorbing sheet is mainly composed of a carbon dioxide gas absorbing resin layer formed by molding into a sheet a blend of an inorganic water retaining agent or an organic water retaining agent whose structure does not change even when it contains water. .

After the water retention agent is retained in water by spraying hot water or cold water onto the carbon dioxide absorbing sheet according to the present invention or by passing the carbon dioxide gas absorbing sheet through hot water or cold water, (i
l Attach the carbon dioxide absorption sheet to the inner wall of the packaging bag, (ii
) A part of the carbon dioxide absorption sheet is fixed to the seal part of the packaging bag to provide the carbon dioxide absorption sheet inside the packaging bag.
(iii) It is possible to produce a packaging container having a function of absorbing carbon dioxide scum by using the carbon dioxide gas absorbing sheet of the present invention, such as forming a part of a pouch, tray, etc. with the carbon dioxide gas absorbing sheet.

In addition, the carbon dioxide absorbing sheet according to the present invention can be used not only as a constituent material of trays and pouches, but also as a constituent material of (i) a membrane of an inner seal, (ii) a constituent material of a blister pack mount) and a bottle cap. It can be applied to sealing materials, etc.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows one embodiment of a carbon dioxide absorbing sheet according to the present invention.

A carbon dioxide absorbing resin made by molding into a sheet a thermoplastic resin blended with an inorganic water-retaining agent that can contain calcium hydroxide and water of crystallization, or an organic water-retaining agent whose structure does not change even when it contains water. A breathable overcoat layer 2 of polyethylene, polystyrene, etc. is provided on both sides of the layer 1.

Note that the breathable overcoat layer may be provided only on one side. In the embodiment described above, the breathable overcoat layer 2 is provided to prevent the carbon dioxide gas absorbing resin layer 1 from coming into direct contact with the product to be enclosed together, and to provide heat sealability to the surface. However, if the surface of the carbon dioxide absorbing resin layer 1 is exposed, it is not necessary if there is no problem in use.

In the above carbon dioxide gas absorbing sheet according to the present invention, the content of calcium hydroxide is preferably 60% or less; if it exceeds 60%, the sheet has poor extrusion suitability and becomes brittle, making it unsuitable for practical use. Next, as the resin to be blended with calcium hydroxide, thermoplastic resins such as polyethylene, polystyrene, polypropylene, polyamide, polyester, etc., and foamable thermoplastic resins made by mixing polystyrene, polyurethane, polyolefin, etc. with a blowing agent can be used. .

Next, in the above carbon dioxide absorbing sheet of the present invention, the water retention agent is mixed with the thermoplastic resin together with calcium hydroxide in order to prevent the reaction between calcium hydroxide and acid gas from proceeding when the water runs out. Examples of water retaining agents include inorganic water retaining agents such as NaC03.1 sail 20, N et SQ.1 L0, Ge ship raIMms Chemicals.
SGP50 manufactured by Sumitomo Chemical Hgdro group ls-50
An organic water retaining agent such as (vinyl alcohol/acrylate copolymer type organic water retaining agent) can be applied.

Next, the present invention will be specifically explained by giving examples and application examples.

Example 1 High impact polystyrene (manufactured by Mitsui Tosho ■, product name:
Toporex 830-55) with 2% by weight of calcium hydroxide (manufactured by Junsei Kagaku) and a water retention agent (anhydrous sodium carbonate).
A blend of 1% by weight was molded using a T-die extruder to produce a sheet with a thickness of 0.25 ribs.

Hot water is poured onto this sheet, the water is retained in the water retention agent to form sodium carbonate decahydrate, and then carbon dioxide gas is added at room temperature for each portion of the sheet's weight after hot water fogging. As a result of examining the absorption capacity, a maximum carbon dioxide absorption capacity of 60' was observed as shown in Figure 2. Example 2 Low density polyethylene (manufactured by Mitsui Polychemicals, trade name;
Mirason-11) Calcium Hydroxide (Junsei Kagaku) 2
0% by weight and water retention agent (SGP manufactured by Boneral Mills)
A blend of 502) 1% by weight was molded using a T-die extruder to produce a sheet with a thickness of 0.25 mm.

Hot water was sprayed onto this sheet to allow the water retention agent to retain water, and then the carbon dioxide absorption capacity was investigated at room temperature for an amount equivalent to 1 female of the sheet after hot water spraying. 3
As shown in the figure, up to 70 carbon dioxide absorbing chambers were seen.
Example 3 High impact polystyrene (manufactured by Mitsui Tosho ■, product name:
Toporex 830-55) is blended with 20% by weight of calcium hydroxide (manufactured by Junsei Kagaku) and 10% by weight of a water retention agent (SGP502 manufactured by GMraIMms), and a foaming agent (Hyowa Kasei, trade name FE-308) is added. was molded using a T-die extruder to produce a sheet with a thickness of 0.25 mm.

Hot water was applied to this sheet to allow the water retention agent to retain the water, and then the carbon dioxide absorption capacity was examined at room temperature for an amount equivalent to 1 female sheet after hot water fogging. As shown in Figure 4, it was found that up to 60% of carbon dioxide gas was adsorbed. Example 4 Low density polyethylene (manufactured by Mitsui Polychemicals, trade name;
Mirason 11) made of calcium hydroxide (Junsei Kagaku) 2
0% by weight and water retention agent (SOP502 manufactured by GMraIMms)
) 1% by weight was blended and a blowing agent (Hyowa Kasei, trade name FE-308) was added and molded using a T-die extruder to produce a sheet with a thickness of 0.25 mm.

This sheet was exposed to hot water, and then the carbon dioxide absorption capacity was examined at room temperature for an amount equivalent to the log weight of the sheet after fogging with hot water. The carbon dioxide absorption capacity was observed. Application example 1 10 female flame-roasted coffee beans and the sheet log of Example 1 were placed in a bag made of a laminated film made of a polyamide film coated with polyvinylidene chloride and laminated with polyethylene on one side.
One bag was vacuum-packed after putting 100 g of flame-roasted coffee beans into the bag, and the other was vacuum-packed after putting only 100 g of flame-roasted coffee beans into the bag. Both bags were stored at room temperature and their changes over time were examined.

As a result, the bag of Example 1 that did not contain the sheet lost its shape over time and began to expand, and finally broke after one month. On the other hand, the bag containing the sheet of Example 1 maintained its packaging bag shape even after one month, thereby maintaining its commercial value.

As described above in detail, the carbon dioxide absorbing sheet of the present invention allows contents that generate carbon dioxide gas, such as roasted coffee beans, to be packaged without causing deformation of the packaging container due to the pressure of the generated gas. I can do it. Moreover, the freshness of fruits and vegetables can be maintained for a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the carbon dioxide absorption properties of the sheet of Example 1; Fig. 2 is a graph showing the carbon dioxide absorption properties of the sheet of Example 1;
The figure is a graph showing the carbon dioxide absorption properties of the sheet of Example 2, Figure 4 is a graph showing the carbon dioxide absorption properties of the sheet of Example 3, and Figure 5 is a graph showing the carbon dioxide absorption properties of the sheet of Example 4. It is a graph. 1... Carbon dioxide absorbing resin layer, 2... Breathable overcoat layer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1 A blend of thermoplastic resin with an inorganic water-retaining agent capable of containing calcium hydroxide and water of crystallization, or an organic water-retaining agent whose structure does not change even when it contains water, and molded into a sheet shape. A carbon dioxide gas absorbing sheet characterized by mainly having a carbon dioxide gas absorbing resin layer made of. 2. The carbon dioxide gas absorbing sheet according to claim 1, characterized in that a breathable overcoat layer made of a thermoplastic resin such as polyethylene or polystyrene is provided on one or both sides of the carbon dioxide gas absorbing resin layer.