JPH04190773A - Freshness keeping tool produced by using new air-permeable and heat-sealable laminated sheet - Google Patents

Abstract

PURPOSE:To obtain the subject tool having excellent freshness-keeping property by applying a specific resin coating liquid to a base paper, bonding the coated paper to a heat-sealable nonwoven fabric in wet state immediately after coating, impregnating the above coating liquid in the nonwoven fabric, drying the product to form a packaging material and sealing a deoxidation agent into the packaging material. CONSTITUTION:A layer of a liquid containing polyolefin resin, acrylic resin, etc., is applied to a base paper having an oil-resistance of >=4 kid, a sizing degree of >=5sec and a gas-permeability of <=20sec and produced by treating a paper sheet with an oil-resistant treatment agent composed mainly of a copolymer composed of a compound having perfluoroalkyl group. After drying the coating layer, the coated paper is further coated with a coating liquid containing polyolefin resin, etc., and immediately bonded in wet state to a nonwoven fabric having a heat-sealing strength of >=800g/15mm width. The above coating liquid is impregnated in the nonwoven fabric and dried as it is to obtain a laminated sheet. The laminated sheet is formed in the form of a bag facing the nonwoven fabric layer inward and a deoxidation agent and an alcohol-containing gas are sealed in the bag to obtain the objective tool.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a freshness-preserving tool containing an oxygen absorber and an alcohol component. More specifically, it is a freshness-keeping tool using a packaging material that has appropriate air permeability and oil resistance, and has excellent tear strength.

(Prior art) Conventionally, food freshness preservation tools have been made by laminating paper or non-woven fabric with perforated polyester, or by integrating paper or non-woven fabric with a film that has been kneaded with an inorganic substance and stretched to maintain air permeability. Oxygen absorbers and alcohol are used in various packaging materials, such as those using films obtained by chemically processing to form microporous membranes, and those made by laminating oil-resistant paper and ethanol-permeable film. Types in which inclusion bodies and the like are encapsulated are known.

(Problems to be Solved by the Invention) Suitability for use as a packaging material for the purpose of this application is to have appropriate ethanol permeability and air permeability as required, and heat sealability. Needless to say, the bag must have tear strength to the extent that it will not break even when used or touched by a small child, it must meet the requirements for sealing against powder, etc., and it must not be used in a high-moisture atmosphere or when exposed to excess water. It is desirable that shrinkage and deterioration do not occur in a dry atmosphere. Furthermore,
In terms of appearance, it is required that the sealing part does not change color or the resin does not melt and become transparent when heat-molded.

As a method of controlling air permeability, it is not possible to obtain an appropriate air permeability by combining materials such as physically punching holes or slits in the film, and when encapsulating powder, 5μ If the following powders are subjected to sudden external pressure, there is a high risk that the powder will blow out, and in applications with high water activity, the contents may seep out. Furthermore, by laminating microporous membranes or moisture-permeable films, it is impossible to obtain a material that is easily permeable with an air permeability of 100 seconds or less, and furthermore, the sole part becomes transparent due to the lack of heat resistance of the heat-sealed part. to degrade.

In order to increase the tear strength of the sheet itself, a method of simply pasting nonwoven fabric or warif onto paper has been used, but there are limits to controlling air permeability, and when used in an atmosphere with high water activity, the contents may seep out. Sole properties are insufficient due to dust and powder. Furthermore, when non-woven fabric or warp is used, there is a risk that voids may be formed in the sealing portion.

In addition, since it is used as a tool to keep food fresh, the packaging material used must be oil-resistant to prevent the oil and fat components contained in the food from coming into direct contact with the oxygen scavenger and alcohol-containing substances inside. Of course.

The conventionally used alcohol-generating color t-o (described in Japanese Patent Application No. 59-4766) is made by laminating a soft resin onto oil-proof paper, and in order to adjust the alcohol permeability, the VA content of the EVA resin must be varied. Either it can be controlled by changing it, or it is not possible to obtain sufficient gas permeability for the purpose of the present invention.

(Means for Solving the Problems) As a result of extensive research in order to solve the problems, the present inventors have found that the present inventors can block the passage of powder, have a tear strength of 250 g or more, have moderate air permeability, and have excellent heat resistance. The present invention was completed by discovering a packaging material with sealing properties and focusing on using this material as a packaging material.

The present invention makes full use of a water-based dispersion coating technique to coat a resin water-based dispersion onto a base paper such as a specific non-woven fabric, paper, oil-proof paper, etc., and immediately joins it with a heat-sealable non-woven fabric in a wet state. The present invention relates to a freshness-preserving tool in which an air-permeable laminated sheet with good heat-sealing property obtained by impregnating the nonwoven fabric with a liquid applied thereto and then drying it as a unit is used as a packaging material to encapsulate an oxygen absorber and an alcohol-containing substance.

First, a method for manufacturing the packaging material used in the present invention will be explained.

The base paper used for packaging material has a large influence on the air permeability after processing, so it is necessary that the air permeability of the base paper is lower than the desired air permeability, and usually 20 seconds or less, preferably 5 seconds. The following is optimal. (The air permeability of paper is expressed as air permeability as shown in JIS P8117.) The size of the base paper is also an important factor for air permeability control,
P8122) A base paper with a size of 5 seconds or more, preferably 20 seconds or more is most suitable. If the base paper has a sizing degree of less than 5 seconds, a sheet with good air permeability as desired cannot be obtained. The coated surface of the base paper is not particularly limited as long as the aqueous dispersion can be applied evenly, but the non-coated surface is preferably glossy and smooth in order to maintain its aesthetic appearance through printing or other processing. In such cases, a smoothness of 5 seconds or more is used.

In the present invention, oil resistance is further required, and the surface or the entire base paper layer is treated with an oil resistance treatment agent whose main component is a copolymer consisting of a perfluoroalkyl group-containing compound, and the oil resistance level is 4 kits. It is most effective to use the above oil-proof paper.

There are no particular restrictions on the nonwoven fabric used for lamination as long as it is a dry or wet nonwoven fabric with good heat sealability, or tear strength (J
ISP-8116) or more than 200g both vertically and horizontally, the air permeability is 5 seconds or less, and the size is 5 seconds or less. Preferably, a spunbond nonwoven fabric made of flexible polyolefin fibers is optimal. Weak non-woven fabrics with a tear strength of less than 200 g will not fulfill the intended function of the packaging material, and non-woven fabrics with an air permeability of more than 5 seconds will have difficulty controlling the air permeability, and non-woven fabrics with a certain size will not be impregnable. Therefore, it does not meet the purpose of the present invention. Examples of such nonwoven fabrics include Elbes (Unitika Co., Ltd.), Melfit (Unicell Co., Ltd.), and Hystar (Teijin Co., Ltd.).

For air permeability control and adhesion between the base paper and the nonwoven fabric, the coating material having heat-sealing and impregnating properties may be a solution type, but an aqueous dispersion is preferred. From a process control point of view, water-based dispersion includes, for example, thermoplastic elastomers such as chloroprene, nitrile, urethane, and styrene-butadiene, low-density polyolefins, ionomers, ethylene-vinyl acetate copolymers, and acrylic resins. To control the air permeability and maintain adhesive strength when bonding the base paper and nonwoven fabric, use a soap-free emulsion with an MFT of 10°C to 50°C. Preferably, carbonaceous, titanium oxide,
It is also possible to add pigments such as aluminum hydroxide and clay. IPA solvent is also effective as a leveling agent.

One or two coat layers are applied depending on the air permeability required for each application. In the case of two-layer coating, lamination with the nonwoven fabric is performed at the time of two-layer coating. The type of coater is not particularly limited as long as it is equipped with equipment capable of coating and bonding, such as a bar coater, roll coater, reverse coater, etc.

The case where water-based dispersion is used will be explained below.

The base paper and nonwoven fabric are bonded together without the use of pressure rolls immediately after applying aqueous dispersion to the base paper, and then dried as is to achieve any air permeability within the range of 1 to 4000 seconds and heat seal strength. 800g/l 5mm width or more (
Heat sealing conditions: 180℃, 1 second, 3kg/crn
2) A laminated sheet with a tear strength of 200 g or more can be obtained.

For applications requiring high adhesive strength between the base paper and the nonwoven fabric, it is preferable to apply the aqueous dispersion in a wet weight of 25 g/m 2 or more to give a dry weight of 7.5 g/m or more.

Precautions for use, manufacturer's name, design, etc. can be appropriately printed on the front surface (base paper @) or back surface (non-woven fabric), preferably on the surface of the sheet thus obtained. When printing, it is better to use a formulation developed by the present inventors that involves impregnating and applying oil-proofing treatment after printing, which reduces the chance of the print coming off and is safe even if it comes into direct contact with food.

The freshness preservation device of the present invention is produced by making a bag of an appropriate size with the heat-sealable nonwoven fabric layer of the laminated sheet obtained as described above inside, and adding an ingredient effective for freshness preservation in the bag. It can be manufactured by encapsulating an oxygen absorber and an alcohol-containing body.

(Function/Effect) The major feature of this laminated sheet is that the nonwoven fabric is impregnated with an air permeability control agent, and the control agent itself has heat-sealing properties and has excellent ethanol resistance. Therefore, there is no deterioration caused by the alcohol component in the packaging material, and sheet troubles that often occur with laminated sheets can be reduced.

(Example) The present invention will be explained below with reference to Examples.

Example 1 Perfluoroalkyl acrylate copolymer (Asahi Glass Co., Ltd.)
Co., Ltd., Asahi Guard AG550), PVA-117 (
A polyoxyethylene alkyl ether derivative (Meinex SO1 manufactured by Meisei Kagaku Co., Ltd.) was added to a 2% solution by blending a polyoxyethylene alkyl ether derivative (Minetics SO1 manufactured by Meisei Kagaku Co., Ltd.) at a solid content weight ratio of 7:3. Make a liquid by adding 1 part by weight to 99 parts by weight.
g, width 43 g, air permeability 2.5 seconds, oil-proof paper (45 g/m2, oil resistance lO kid, air permeability 2. 5 seconds, size degree 20 seconds).

Next, on this oil-proof paper, 8 parts by weight of Chemipearl A-100 (thermoplastic elastomer disversion, Mitsui Petrochemical Co., Ltd.), 2 parts by weight of Movinyl 081 (manufactured by Hoechst Synthetic Co., Ltd., acrylic emulsion), IPAIO
% (based on solution) (solid content: 20 wt.
", no size, manufactured by Unitika Co., Ltd.) was laminated together, the non-woven fabric side was also impregnated, and dried at 110°C.
8g/m2, air permeability 200 seconds, size degree 900 seconds, heat seal strength 2kg/15cm (heated at 180°C for 1 second, pressure 3kg/cm), tear length 440g
A laminated sheet weighing 720 g in width was obtained.

Table 1 shows the main physical properties of the obtained sheet.

A packaging material having an actual use area of 52.5 cm2 was prepared by heat-sealing the nonwoven fabric surfaces of this sheet. In this packaging material, 0.9 g of reduced iron powder, 001 g of common salt, and 1 g of silica powder impregnated with 1.8 times the amount of ethanol were sealed, and the following tests were conducted using this as a test sample. went.

■Ethanol vapor permeability The amount of ethanol dissipated from the test sample was investigated in an atmosphere of 40°C.

■02 concentration test sample adjusted to 30℃ and 90% humidity at 500 m
The mixture was placed in a 1-liter sealed glass container, and the 02IIA degree was checked after 16 hours.

■ After leaving the sample to be tested for fungal count in an atmosphere of 30°C and 70% humidity for 30 minutes, use a commercially available castella castella in a KNy/PE bag (fungal count 1.2XIO3 at the time of purchase, weight 200g, water activity (1i !0.90) and stored at 25°C for 20 days, the number of fungi (numbers/g) of castella was measured.

The obtained results are summarized in Table 1.

Example 2 First, 5 g/m2 of solid Chemipearl S-100 (ionomer dispersion manufactured by Mitsui Petrochemicals Co., Ltd.) was coated and dried as a first layer on the same oil-proof paper as in Example 1. To, Chemipearl A-100 (thermoplastic elastomer disversion, Mitsui Petrochemical Co., Ltd. i1)
8 parts by weight, Movinyl'081 (manufactured by Hoechst Synthetic Co., Ltd., acrylic emulsion) 2 parts by weight, IPAIO%
(vs. solution) was applied to a spunbond nonwoven fabric similar to Example 1 (Elbes SO203WDO 1 tsubo 20g/20g/cm2).
m", no size, Unitika Co., Ltd. U), impregnated the non-la fabric side and dried at 110℃,
5g/m2, air permeability 1000-1500 seconds, size degree 9
00 seconds, heat seal strength 2kg/15mes radiation (18
A laminated sheet was obtained by heating at 0° C. for 1 second at a pressure of 3 kg/cm” and having a tear degree of 410 g vertically and 730 g horizontally. Table 1 shows the main physical properties of the obtained sheet.

A packaging material having an actual use area of 52.5 cm2 was prepared by heat-sealing the nonwoven fabric surfaces of this sheet. In this packaging material, 0.9 g of reduced iron powder, 001 g of common salt, and 1 g of silica powder impregnated with 1.8 times the amount of ethanol were sealed, and this was used as a test sample in the same manner as in Example 1. The test was conducted. The obtained results are summarized in Table 1.

Comparative Example 1 Chemipearl (
Ionomer Disversion (manufactured by Mitsui Petrochemical Co., Ltd.) was coated in two layers with a solid content of 10 g/rn, and this was laminated with a microporous film (TSF-EU, manufactured by Kojin Co., Ltd.) with an air permeability of 350 seconds. A composite sheet was obtained. Table 1 shows the main physical properties of the obtained sheet.

Using this composite sheet, a similar packaging material was produced in the same manner as in Example 1 with the film side facing inside. Next, a test sample was prepared from this packaging material in the same manner as in Example 1, and the characteristics were evaluated in the same manner as in Example 1 (Table 1).
This had the disadvantage that the ethanol component in the packaging material would volatilize if the work was not completed in a short time. In addition, the microporous film becomes transparent when wetted with ethanol, and the iron component powder of the oxygen scavenger can be seen through, and the heat-sealed portion becomes transparent, making it unsuitable for use in food applications. Ta.

Comparative Example 2 Perfluoroalkyl acrylate copolymer (Asahi Glass (
Co., Ltd. U, Asahi Guard AG550), PVA-117 (
A polyoxyethylene alkyl ether derivative (Meinex SO1 Meisei Kagaku Co., Ltd.) was blended with a 2% solution of polyoxyethylene alkyl ether derivative (manufactured by Kuraray Co., Ltd.) at a solid content weight ratio of 7:3, and the above copolymer solid was added to the solid content. A liquid was prepared by adding 1 part by weight to 99 parts by weight, and a non-woven fabric made of 40 parts by weight of valve and 60 parts by weight of polyethylene terephthalate (44 g/m2
2) and dried with a drum dryer to produce an oil-resistant nonwoven fabric (basis: 45 g/rn2).

This oil-resistant non-woven fabric and a perforated polyethylene sheet having a basis weight of 35 g/m 2 were laminated together by hot pressing using a hot roll to obtain a laminated sheet having an air permeability of 10 seconds. Table 1 shows the main physical properties of the obtained sheet.

Next, a packaging material with an actual use area of 52.5 cm2 was prepared by heat-sealing the perforated polyethylene sheets of this sheet, and a test sample was prepared in the same manner as in Example 1. The characteristics were evaluated. The obtained results are summarized in Table 1.

Because the packaging material had a high ethanol permeability, the alcohol evaporated before it was placed in the product packaging, resulting in insufficient efficacy.

Comparative Example 3 An ethylene vinyl acetate copolymer resin (hereinafter abbreviated as EVA) having a vinyl acetate content of 119.0% and an MI of 15 was extruded through a T-die and laminated onto oil-proof paper produced in the same manner as in Example 1. A laminated sheet was obtained. Table 1 shows the properties of the obtained laminated sheet.

Next, the EVAF of this laminated sheet! A packaging material similar to that in Example 1 was prepared with the inside of the sample, and a test sample was also prepared in the same manner as in Example 1, and the characteristics were evaluated in the same manner as in Example 1. The results obtained are shown in Table 1.

The packaging material has a high air permeability, making it difficult for oxygen to pass through, so the oxygen removal effect was insufficient. Furthermore, since the heat sealing strength was low, when the bag was pulled with both hands, it broke and the iron component powder inside was scattered.

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Claims (1)

[Claims] The surface or entire layer is treated with an oil-resistant treatment agent whose main component is a copolymer containing a perfluoroalkyl group-containing compound, and has an oil resistance of 4 kids or more, a size degree of 5 seconds or more, and an air permeability of 20 seconds or less. If desired, a layer of a liquid containing one or more blends selected from the group consisting of polyolefin resins, ionomer resins, elastomer resins, and acrylic resins is applied to the base paper and dried, and then polyolefin resins, ionomer resins, and elastomer resins are applied. Apply a coating solution containing one or more selected from the group consisting of resins and acrylic resins, and immediately heat seal in a wet state with a strength of 800 g/15 mm width, a tear strength of 200 g or more, an air permeability of 5 seconds or less, and a size degree. The nonwoven fabric layer of the laminated sheet having air permeability and heat sealability with an air permeability of 1 to 4000 seconds obtained by bonding with a nonwoven fabric for 5 seconds or less, impregnating the nonwoven fabric with the applied liquid, and drying as it is, is attached to the inner side. A freshness-preserving tool in which an oxygen absorber and an alcohol-containing substance are heat-sealed into a packaging material that has the following properties.