JPH08267672A - Deoxidation and alcohol elimination-jointly used freshness-keeping packaging material - Google Patents

Abstract

PURPOSE: To provide a laminated sheet capable of preventing sufficiently oozing out of water soluble contents in high water content atmosphere. CONSTITUTION: For a deoxydation and alcohol elmination-jointly used freshness- keeping packaging material, a water series dispersion applied layer of resin is provided to base paper, and good water repellency by application and impregnation of fluororesin is given to at least one side of a sheet by using the sheet to which a non-woven fabric having gas permeability and a heat sealing property is stuck while the applied layer is of a wet state. Herein, as the base paper, a surface or all layers of the base paper of at least 5sec sizing degree and at most 20sec air permeability to which resin is applied, are treated by an oilproof treating agent having copolymer composed of a compound containing a perfluoroalkyl group as a main component, which is composed of natural pulp or synthetic fiber consisting of hydrophobic polymer of at least 4 kid grease proofness, and its wet strength is made at least 0.5kg/15mm width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material that requires air permeability and a lid material for a container. Sheet-processed products, fruit-processed products, powder-processed products, tablets for the purpose of maintaining the freshness of foods, antifungal, antibacterial, insecticidal, deodorant, aroma, dehumidifying, and moisture permeable. After encapsulating the processed product in a breathable packaging material, heat sealing and using it as it is,
It is used by putting it in a separate container. In addition, a substance which becomes a liquid by absorbing moisture, an oil or a water-based substance may be put in a plastic container and a breathable sheet may be required as a lid material. The present invention is an invention relating to such a field.

[0002]

2. Description of the Related Art Conventionally, as a breathable heat seal material,
Paper or nonwoven fabric laminated with hole poly, inorganic material kneaded into the film to maintain air permeability and integrated with paper or nonwoven fabric, resin with different melting point is extruded to form a matrix and integrated with paper or nonwoven fabric Other than the above, there is one using a film obtained by forming a microporous film by chemical treatment. In order for these sheets to be used in the packaging materials mentioned above, it is possible to control the appropriate air permeability according to the requirements, not to mention the heat sealing property, and the safety as a packaging material. High hygiene (tearing strength that does not break for children who cannot read letters), powder powder sealing suitability is required when filling powder etc., and the seal part discolors during heat sealing It is required that the resin does not become transparent due to melting. Further, it is desired that shrinkage inferiority or the like does not occur in a high moisture atmosphere or an overdry atmosphere. However, the method of compounding physically punched holes or slits in the film lacks uniformity of air permeability, and when the powder is included, the powder of 5 μm or less is exposed to a sudden external pressure. When exposed to dust, there is a high risk that the powder will be wiped out, or the contents will be exuded in applications with high water activity. In addition, it is impossible to control the air permeability for 100 seconds or less by laminating a microporous film or a moisture permeable film, and the heat seal of the heat seal is insufficient and the seal becomes transparent and deteriorates. Although a method of simply pasting a non-woven fabric or a wariff on paper is used to increase the tear strength of the sheet itself, but there is a limit to the control of air permeability, and the contents exude when used in an atmosphere with high water activity. The sealability with dust is insufficient.
Further, when a non-woven fabric or a wariff is used, there is a risk that voids will be formed in the seal portion.

An object of solving the above-mentioned problems is reported in Japanese Patent Laid-Open No. 4-59247. In this publication, one of a specific non-woven fabric, paper, oil-resistant paper or the like is used as a base paper, a water-based dispersion of a resin is applied onto the base paper, and immediately after that, a non-woven fabric having a breathable and heat-sealing property in a wet state. There is disclosed a breathable sheet having a good heat-sealing property, which is obtained by sticking together, impregnating the liquid applied to the non-woven fabric, and drying as it is.

However, the effect of preventing the water-soluble contents from seeping out in the high-moisture atmosphere (atmosphere with high water activity) of the laminated sheet disclosed in this publication is not sufficient. This laminated sheet has a remarkable effect of preventing the exudation of the contents when compared with a laminated sheet in which a nonwoven fabric or a walliff is simply pasted on paper, but the water-soluble contents exude to discolor the laminated sheet. In some cases, the purpose of use was not fulfilled.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to solve such problems, and is a non-woven fabric having breathability and heat-sealing property, which is made of one of specific paper, non-woven fabric, oil-resistant paper, etc. as a base paper. It is an object of the present invention to provide a laminated sheet having air permeability and heat sealability, which is integrated with each other, capable of sufficiently preventing exudation of contents in a high moisture atmosphere (atmosphere with high water activity) without impairing various physical properties. It is intended.

[0006]

SUMMARY OF THE INVENTION The inventor
In a laminated sheet having good air permeability, which is obtained by integrating a non-woven fabric, a base paper such as oil-resistant paper, and a nonwoven fabric having air permeability and heat sealability, when a water repellent treatment with a fluororesin is applied to at least one side of the laminated sheet, It was found that a laminated sheet can be obtained in which the exudation of the contents in a high-moisture atmosphere (an atmosphere with high water activity) can be sufficiently prevented without impairing the physical properties, and the present invention was accomplished. That is, the present invention, the base paper is provided with a resin aqueous dispersion coating layer, while the coating layer is in a wet state, using a sheet laminated with a nonwoven fabric having air permeability and heat sealability, at least one side of the sheet In addition, it is a deoxygenating / alcohol combined freshness-keeping packaging material that is made to have strong water repellency by applying and impregnating fluororesin. Further, the base paper preferably has physical properties of a size degree of 5 seconds or more and an air permeability of 20 seconds or less, more preferably a size degree of 5 seconds or more and an air permeability of 20 seconds or less.
Those satisfying at least one of the conditions are desirable. The surface of the base paper to which the resin is applied or the entire base paper layer is treated with an oil-resistant treatment agent containing a copolymer of a perfluoroalkyl group-containing compound as a main component, and the oil resistance is 4 kid or more. It consists of fibers of a hydrophobic polymer. Made of natural pulp or synthetic fiber, with a wet strength of 0.
The width is 5 kg / 15 mm or more.

Since the base paper used in the present invention greatly contributes to the air permeability after processing, it is required that the air permeability of the base paper is lower than the target air permeability, 20 seconds or less, more preferably. 5
Optimally less than a second (air permeability of paper is expressed as air permeability as shown in JIS P8117). The sizing degree of the base paper is also an important factor for controlling the air permeability, and a sizing degree (Stecht sizing degree JIS P8122) of 5 seconds or more, more preferably a sizing degree of 20 seconds or more is most suitable. Oil-resistant paper is most effective for this type. If the sizing degree is less than 5 seconds, the desired sheet having good air permeability cannot be obtained. The coated surface of the base paper is not particularly limited as long as the water-based dispersion can be coated evenly, but the non-coated surface is preferably glossy and smooth in order to maintain the aesthetics by processing such as printing. In such a case, a smoothness of 5 seconds or more is adopted.

More specifically, the base paper may be one that satisfies at least one of the following three conditions when oil resistance is required. A base paper whose surface or the entire base paper layer is treated with an oil-resistant treatment agent whose main component is a copolymer consisting of a compound containing a perfluoroalkyl group, and whose oil resistance is 4 or more. Base paper made of fibers of hydrophobic polymer. Made of natural pulp or synthetic fiber, with a wet strength of 0.
Base paper with a width of 5 kg / 15 mm or more.

As a coating material having air permeability control, adhesion to base paper, heat sealability and impregnation property, there are water-based dispersions such as thermoplastic elastomer, low density polyolefin, ionomer, vinyl acetate copolymer polyolefin. Soapless emulsion with MFT of 10 ° C to 50 ° C is used to control the air permeability when the base paper and the non-woven fabric are attached and to further maintain the adhesive strength. It is preferable to use, and it is also possible to add pigments such as calcium carbonate, titanium oxide, aluminum hydroxide and clay. An IPA solvent is also effective as a leveling agent.

The coat layer is 1 depending on the required air permeability for each application.
Layers or two layers are coated. When a two-layer coating is performed, the bonding with the non-woven fabric is performed at the time of the two-layer coating. The type of coater is not particularly limited as long as it is equipped with a bar coater, a roll coater, a reverse coater, and the like that can be coated and laminated.

The non-woven fabric used for bonding is not particularly limited as long as it is a dry or wet non-woven fabric having a good heat-sealing property, but the tear strength (JIS P-8116) is 200 g for both vertical and horizontal.
It is indispensable that the air permeability is 5 seconds or less and the size is 5 seconds or less. A spunbonded nonwoven fabric made of a flexible polyolefin fiber is most preferable. A weak non-woven fabric having a tear strength of less than 200 g does not satisfy the function of the target packaging material, and a product having an air permeability of more than 5 seconds is difficult to control the air permeability, and a non-woven fabric having a size has poor impregnability. It does not meet the purpose of the invention. Examples of the type of non-woven fabric include Elves (Unitika Ltd.), Melfit (Unicel Ltd.), Hyster (Teijin Ltd.) and the like.

The base paper and the non-woven fabric are bonded together by applying an aqueous dispersion onto the base paper immediately after coating without using a pressure-bonding roll, and by drying as it is, it has an arbitrary air permeability in the range of 1 to 4000 seconds. , Heat seal strength 800g / 15
mm width or more (heat sealing condition: 180 ° C, 1 second, 3k
g / cm ^2), more laminated sheet tear strength 200g is obtained. For applications that require adhesive strength between the base paper and the non-woven fabric, the water-based dispersion should have a dry weight of 7.5 g / m ²
It is preferable to apply the wet weight of 25 g / m ² or more so as to achieve the above.

For the water repellent treatment with a water repellent, a fluororesin, preferably a perfluoroacrylic copolymer, is used as the water repellent, and the base paper surface side and / or the non-woven cloth surface of the sheet obtained by laminating the base paper and the non-woven cloth. Apply and impregnate the side. In particular, application / impregnation from the base paper surface side is preferable. As the water repellent, it is not possible to apply a water repellent having excellent film-forming property that impairs air permeability of a sheet obtained by laminating a base paper and a non-woven fabric. Further, the effect of the present invention cannot be obtained with a simple surface coating. The sheet to be applied / impregnated may be a printed sheet. The coating / impregnation amount of the water repellent used in the water repellent treatment is preferably 0.1 to 1.0 g / m ² .

[0014]

【Example】

Example 1 Perfluoroalkyl acrylate copolymer (Asahi Guard AG550 manufactured by Asahi Glass Co., Ltd.), PVA-117
(Kuraray Co., Ltd.) in a solid component weight ratio of 7: 3 was added to a 2% by weight solution of polyoxyethylene aliphatic ether derivative (Meisei Chemical Co., Ltd., Minex SO) in solid component weight. A liquid was prepared by adding 1 part by weight to 99 parts by weight of the solid content of the copolymer, and the total weight was 44 g / m ² , and the tear strength was 23.
oil-free paper (45 g / m ² , oil resistance 10 kid, air permeability 2) impregnated with non-sized base paper (rayon mixed paper ratio 13%) having air permeability of 2.5 g and horizontal width of 43 g and dried with a drum dryer. .5 seconds, size degree 20 seconds). Chemipearl S-100 (Ionomer Dispersion manufactured by Mitsui Petrochemical Co., Ltd.) was applied at a solid content of 5 g / m ² and dried, and A-100 (thermoplastic elastomer dispersion, Mitsui Petrochemical ( Co., Ltd.) 8 parts by weight, Movinyl 081 (Hoechst Synthetic Co., Ltd., acrylic emulsion) 2 parts by weight, and mixed with IPA 10% (to solution)
A wet weight of 40 g / m ^{2 was} added and coated, and immediately a spunbonded non-woven fabric composed of EA fiber (Elves SO 203 WDO, rice grammage 20 g / m ² , no size,
Unitika Co., Ltd.) is stuck and impregnated at 110 ° C.
And dried to obtain a laminated sheet A. Physical properties of the obtained laminated sheet A are 80.9 g / m ^{2 of} tsubo and air permeability of 1500-500.
2000 seconds, size degree 1100 seconds, heat seal strength 2
More than kg / 15mm width (180 ° C, 1 second, 3kg / cm
² ), the tear degree was 600 g. Next, on one surface of the laminated sheet A, 0.3 g of a perfluoroacrylate copolymer was added.
/ M ² coating / impregnation and drying to obtain laminated sheets B (base paper surface side coating) and C (nonwoven fabric surface side coating) having water repellency R10.

Table 1 shows the results of evaluation of seepage of the contents of the obtained laminated sheet in a high humidity atmosphere. For the evaluation of the bleeding of the contents, cut the sheet into 5 cm × 10 cm, make a 5 cm × 5 cm three-sided seal bag, fill it with an oxygen scavenger / powdered alcohol as the contents, and then measure relative humidity RH 90% or more. Was exposed to the atmosphere and the surface of the bag was observed.

[0016]

[Table 1] Evaluation of bleeding of contents: ◎ No bleeding, ○ No bleeding, △ Many bleeding.

[0017]

EFFECTS OF THE INVENTION The laminated sheets B and C of the present invention are treated in a high moisture atmosphere (atmosphere with high water activity) as compared with the laminated sheet A having the conventional structure by the treatment of the water repellent with a fluororesin. Excellent in exudation prevention. In particular, no bleeding was observed in B.

Claims (3)

[Claims] 1. A base paper is provided with an aqueous dispersion coating layer of resin, and while the coating layer is in a wet state, a sheet obtained by laminating a nonwoven fabric having air permeability and heat sealability is used, and at least one side of the sheet is used. Fluorine resin application
A freshness-maintaining packaging material that combines deoxidization and alcohol with strong water repellency by impregnation. 2. The base paper has a size degree of 5 seconds or more and an air permeability of 20.
2. The deoxygenation / alcohol combined freshness-keeping packaging material according to claim 1, which has physical properties of not more than a second. 3. The deoxygenating / alcohol combined freshness-keeping packaging material according to claim 2, wherein the base paper satisfies at least one of the following three conditions. The surface of the base paper to which the resin is applied or the entire base paper layer is treated with an oil-resistant treatment agent containing a copolymer of a perfluoroalkyl group-containing compound as a main component, and the oil resistance is 4 kid or more. It consists of fibers of a hydrophobic polymer. Made of natural pulp or synthetic fiber, with a wet strength of 0.
The width is 5 kg / 15 mm or more.