JPH06126874A - Packaging sheet - Google Patents

Abstract

PURPOSE:To provide a packaging sheet of food preservative optimum to perform a function of the preservative while effectively shutting OFF a vessel content against the preservative. CONSTITUTION:A packaging sheet comprises a support layer made of woven or nonwoven fabric on a surface having no dense layer of an asymmetrical porous layer formed with a dense layer on a surface, wherein the woven or nonwoven fabric contains polymer component having a melting point of 100-170 deg.C and a thermally deforming temperature of the material for forming the porous layer is 170 deg.C or higher.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a packaging sheet for packaging a food preservative.

[0002]

2. Description of the Related Art Conventionally, as a packaging sheet for food preservatives, non-woven fabrics, porous films and the like having pores are used, and in order to prevent water or oil from entering through the pores. In some cases, a material having water / oil repellency is applied to the surface. However, when it is brought into contact with the contents containing water, oil or alcohol for a long period of time, water penetrates inside the packaging sheet, which impairs the air permeability of the packaging sheet or food preservative. In some cases, water and the like penetrated into the product to reduce the ability of the food preservative, and in some cases water and the like penetrated into the food preservative and the food preservative eluted out of the packaging sheet.

In order to solve such a problem, in JP-A-56-2164, a composite packaging material having two layers of a non-woven fabric layer and a layer having oxygen gas permeability and water impermeability is provided with oxygen. An oxygen absorber used as a sheet for packaging an absorber, in JP-A-1-167079, an inner layer made of a resin material having an oxygen permeability, which is easy to heat seal with an outer layer of poly-4-methylpentene. An oxygen-absorbing package in which an oxygen-absorbing material is housed between laminated bodies, JP-A-62-122569 discloses an oxygen-absorbing package in which an oxygen-absorbing agent is placed in a limited space partitioned by a selective oxygen-permeable membrane. The body is devised.

[0004]

However, in the oxygen absorbers described in JP-A-56-2164 and JP-A-1-167079, a non-woven fabric or a resin material which is easily heat-sealed and has oxygen permeability is disclosed. Since a water-impermeable resin layer is directly provided on the (nonwoven fabric), it is difficult to form a defect-free homogeneous resin layer, and in order to form a defect-free homogeneous resin layer, It was necessary to thicken the resin layer, and it was impossible to obtain an oxygen absorber having a high oxygen absorption rate.

[0005]

In order to solve such a problem, the present invention has the following constitution.

"In a sheet having a supporting layer made of a woven or non-woven fabric on the surface of the asymmetric porous layer having a dense layer formed on the surface not having the dense layer, the woven or non-woven fabric has a melting point of 100 ° C or more. A packaging sheet comprising a polymer component having a temperature of 170 ° C. or lower and having a heat distortion temperature of 170 ° C. or higher of the material forming the asymmetric porous layer. ”A flat film used in the present invention. The composite membrane has an asymmetric porous layer having a dense layer formed on the surface.

The asymmetric type porous layer has an asymmetric structure in the film thickness direction, and the size of the pores of the dense layer on the surface is 0.
001 to 0.5 μm, preferably 0.005 to 0.1 μm
m. This value is extremely smaller than that of a conventional porous film that does not have an asymmetric structure, and has an excellent liquid blocking ability. The thickness of the porous layer is usually 1 to 30 in order to have practical mechanical strength and to obtain a sufficient gas permeation rate.
It is 0 μm, preferably 10 to 100 μm. As the asymmetric type porous layer, a layer formed by a known method, for example, a wet method, a dry / wet method, a melting method, a stretching method or the like is appropriately used. As a material for forming the porous layer, aromatic polysulfone-based materials such as aromatic polysulfone, aromatic polyether sulfone, and polyphenylene sulfide sulfone,
Cellulose-based materials such as cellulose acetate, ethyl cellulose, cellulose, polyolefin-based materials such as polyacrylonitrile, polypropylene and polyethylene, fluorine-containing polymer materials such as polyvinylidene fluoride and polytetrafluoroethylene, polyamide-based materials or polyimide-based materials, etc. Can be used. Among these,
When the packaging sheet of the present invention is processed into a bag shape by a thermal method such as heat sealing or ultrasonic sealing, there is no reduction in gas permeability due to deformation of the asymmetric porous layer or blockage of pores in the dense layer. A material having a heat distortion temperature of 170 ° C. or higher is preferable. The heat distortion temperature referred to in the present invention is ASTM-D64.
8 and JIS-K7207, the temperature at which the test piece shows a predetermined amount of deformation when the temperature is continuously raised at a constant rate under a constant load. In the present invention, 1
The temperature when the load is 8.6 kgf / cm ² . Among materials having a heat distortion temperature of 170 ° C. or higher, aromatic polysulfone-based materials such as polysulfone (heat distortion temperature 174 ° C.) and polyether sulfone (heat distortion temperature 202 ° C.) are particularly preferable because the pore diameter can be easily controlled. The gas permeability of the porous layer provided on the base material is 10 to 10 at the air permeation rate.
About 000 [m ³ / m ² · hr · atm] is preferable.

The flat membrane composite membrane has a woven or non-woven fabric on one surface of the asymmetric porous layer. The woven or non-woven fabric used as the base material is a portion that supports the asymmetric porous layer formed thereon, has sufficient air permeability, and has good mechanical strength. Heat-sealable materials are preferable in order to increase the efficiency of the work of packaging the food preservative.

Polyolefins such as polyethylene, polypropylene, etc. having such characteristics,
Known woven or non-woven fabrics made of polyesters such as polyethylene terephthalate and polyamides such as nylon can be used. Among these, it is necessary to use a woven or non-woven fabric containing a polymer component having a melting point of 170 ° C. or less, which can be easily processed by ordinary heat sealing or ultrasonic sealing. Examples of these are polyethylene (melting point 107 to 140 ° C.), polypropylene (melting point 16
7-170 ° C.), ethylene-vinyl acetate copolymer (melting point 103-108 ° C.), woven or non-woven fabric containing single-component fibers, polypropylene / polyethylene, polyester / copolyester, polyester / polyethylene or the like in parallel or A woven fabric or a non-woven fabric containing heat-sealing fibers having a sheath-core structure can be used, but the present invention is not limited thereto. In the present invention, the melting point is 170 ° C.
By combining a woven or non-woven fabric containing the following polymer components with an asymmetric porous layer having a heat distortion temperature of 170 ° C or higher, it can be easily processed by ordinary heat sealing or ultrasonic sealing, and is asymmetric porous. The food preservative packaging sheet does not have a decrease in gas permeability due to layer deformation and blockage of pores in the dense layer.

When it is necessary to store a liquid having a small surface tension such as alcohol or to completely stop the liquid under pressure, a flat membrane composite membrane is a polymer homogeneous thin film layer on one side of an asymmetric porous layer. May have. The polymer homogeneous thin film layer is a layer that prevents the permeation of liquids such as water and oil and permeates oxygen, ethylene, and alcohol, and the polymer constituting this layer is, for example, an oxygen permeability coefficient as a measure of permeability. When P _O2 is used, P _O2 is 1 × 10 ⁻¹⁰ [cm ³ · cm / cm ² ·
sec · cmHg] or more, more preferably 1 × 10 ⁻⁹
More than [cm ³ · cm / cm ² · sec · cmHg] is more preferable. Examples of the polymer having an oxygen permeability coefficient within the above range include polyorganosiloxanes such as polydimethylsiloxane and polymethylphenylsiloxane, crosslinked polyorganosiloxanes, and polyorganosiloxane /
Polyorganosiloxane copolymers such as polystyrene copolymer, polyorganosiloxane / polycarbonate copolymer, polyorganosiloxane / polysulfone copolymer, poly (4-methylpentene-1), poly (di-te)
rt-butyl fumarate) and other polyolefins, poly (2,6-dimethyl-1,4, -phenylene oxide)
Polyphenylene oxides such as, poly (trimethylsilylpropyne), substituted acetylene polymers such as poly (tert-butylacetylene), celluloses such as ethyl cellulose, polyorganophosphazenes such as poly (bisethoxyphosphazene), etc. However, as long as the oxygen permeation coefficient substantially satisfies the above range, the oxygen permeation coefficient is not limited to these and can be used. Other polymers may be added to the polymer forming the homogeneous thin film layer as long as the permeability of the thin film layer is not impaired. The addition method includes a mixing method and a laminating method. The polymer forming the homogeneous thin film layer may have a crosslinked structure.

The thickness of the homogeneous polymer thin film layer is generally 0.01 because if the film thickness is too thin, the mechanical strength of the thin film layer will decrease, and if it is too thick, the oxygen permeation rate will decrease.
It is suitable that the thickness is -3 μm, preferably 0.05-1 μm.

In the case of a flat membrane composite membrane used in the present invention, in which a polymer homogeneous thin film layer is provided on an asymmetric porous layer,
The oxygen transmission rate Q _O2 is 0.01 to 50 [m ³ / m ² ·
hr · atm], more preferably 0.5 to
15 [m ³ / m ² · hr · atm] is used.
Ethylene gas permeation rate Q _O2 is 0.01 to 50 [m ³ / m
² · hr · atm], more preferably 0.
5 to 15 [m ³ / m ² · hr · atm], ethyl alcohol gas permeation rate Q _O2 is 1.0 to 5000 [m ³ / m
² · hr · atm] is preferable, and more preferably 50
˜1500 [m ³ / m ² · hr · atm] is used.

When the oxygen permeation rate, the ethylene permeation rate and the alcohol permeation rate are lower than the above ranges, the absorption rate of oxygen and ethylene absorbed in the food preservative decreases, and the alcohol release rate from the food preservative decreases. It decreases and becomes unfavorable. If the oxygen permeation rate, the ethylene permeation rate and the alcohol permeation rate exceed the above ranges, the flat membrane composite membrane is likely to be damaged due to contact with other substances, which is not preferable.

Further, the polymer homogeneous thin film layer contained in the flat membrane composite film is preferably a pinholeless homogeneous layer, and the homogeneity thereof is used as an index for the oxygen / nitrogen permeation rate ratio α.
It can be expressed by using (= Q _O2 / Q _N2 ). When the inherent oxygen / nitrogen permeation rate ratio of the material forming the polymer homogeneous thin film layer is α ^* , α of the flat membrane composite film is preferably 0.5α ^{* to} 2.0α ^* , more preferably Is 0.8
α ^{* to} 1.5α ^* . When α of the flat membrane composite film is lower than the above range, it is not preferable because pinholes exist in the polymer homogeneous thin film layer, and when α exceeds the above range,
Since the porous layer is impregnated with the polymer homogeneous thin film layer, the oxygen permeation rate of the flat membrane composite membrane is lowered, which is not preferable.

Known food preservatives can be used as they are. For example, as the oxygen absorbent, ascorbic acid, ascorbate, isoascorbic acid, isoascorbate, gallic acid, gallate, tocopherol, hydroquinone, catechol, resorcin, dibutylhydroxytoluene, dibutylhydroxyanisole,
Organic oxygen absorbers such as pyrogallol, rongalit, sorbose, glucose, lignin, etc., inorganic oxygen absorbers such as iron powder, iron salts, sulfites, thiosulfates, dithionite salts, bisulfite salts and redox resins One or a mixture of two or more selected from polymer oxygen absorbers such as polymer metal complexes and oxygen absorbers such as zeolite and activated carbon is appropriately used according to the use conditions. Further, the oxygen absorbent may contain other substances such as a catalyst and a water retention agent in order to control the oxygen absorbing ability. As the ethylene absorbent, a known one can be used as it is. For example, an adsorbent mainly composed of activated carbon, an adsorbent composed mainly of potassium permanganate, an adsorbent composed of activated carbon adsorbing potassium permanganate, and granular activated carbon reacted with potassium bromate and a dilute acid and dried. One kind or a mixture of two or more kinds selected from the adsorbents is appropriately used according to the use conditions. Especially, the adsorption type has moisture,
The packaging sheet of the present invention is preferable as such a packaging sheet because it has the drawback of releasing ethylene once adsorbed. As the alcohol generating agent, a powdered alcohol preparation, an ethanol generating type oxygen scavenger or the like is appropriately used according to the use conditions. In addition, the present invention can be applied to food preservatives such as antibacterial / bacteriostatic agents, carbon dioxide removing agents and gas generating agents.

In addition to using these food preservatives alone,
It may be mixed with other substances, such as being embedded in a resin for handling or morphology.

The packaging sheet of the present invention is a flat film-like composite film for packaging a food preservative. However, when the food preservative itself is packaged, the food preservative is not exposed to the outside so as to have a flat film shape. It is necessary to seal the composite membrane in a bag. As a sealing method, there are a heat sealing method, an adhesive method, and a method of sealing the sealing portion with another material. Of these, the method using heat sealing is particularly preferable because it is simple in production. Further, when packaging a food preservative, in addition to the method of packaging the food preservative itself or the entire circumference of the package with a flat membrane composite membrane, only a part of the flat membrane composite membrane, There is a method of wrapping the part with another material (for example, metal, resin molded product, polymer film, etc.).
Further, a method of directly contacting the food preservative with the flat membrane composite membrane, a method of providing a sheet-shaped spacer between the food preservative and the flat membrane composite membrane, and a woven or non-woven fabric included in the flat membrane composite membrane. It is possible to use various methods such as a method of partially impregnating the base material and / or the porous layer with the food preservative.

The packaging sheet of the present invention is effective for packaging food preservatives used for beverages, high-moisture foods, foods containing water drops, and the like. For example, in beverages, alcoholic beverages, juice, milk, etc., in high-moisture foods, boiled fish, miso, ketchup, raw noodles, roe, etc. It is suitable for packaging food preservatives such as cooking sauces, chazuke, pickles, processed mushrooms, processed foods such as jam, especially liquid foods and water-containing foods, and it is recommended that moisture and water droplets contact the food preservatives. By preventing the deterioration of the performance of the food preservative and the elution of the food preservative can be prevented. In addition, it is suitable for fruits and vegetables, cut vegetables, fresh flowers, cheese, butter, dairy products such as ice cream, fermented foods, and honey. The food preservative using the packaging sheet is brought into direct contact with these foods, or by arranging them at a certain distance from them, oxygen in the food or oxygen in the atmosphere around the food and Absorbs ethylene and other substances that come out to prevent deterioration and maintain quality. In addition, it is possible to prevent deterioration of foods and maintain quality by alcohol generated from food preservatives.

[0019]

The present invention will be described in more detail by the following examples.

The performance of a flat membrane-like composite membrane is as follows:
The pressure on the primary side is set to 2 atm, the pressure on the secondary side is set to 1 atm, and the gas (oxygen or nitrogen) permeation rate is set to the precision membrane flow meter SF-1.
It was measured with 01 (made by Standard Technology).
The oxygen permeation rate Q _O2 is [m ³ / m ² · hr · at] as a unit.
m 2] and used as an index of gas permeability of the flat membrane composite membrane. In addition, the oxygen / nitrogen permeation rate ratio α of the flat membrane composite membrane
Was calculated from Q _O2 / Q _N2 and used as an evaluation criterion for the homogeneity of the polymer thin film layer contained in the composite film.

The oxygen / nitrogen permeation rate ratio α ^* (= P _O2 / P _N2 ) and the oxygen permeation coefficient P _O2 peculiar to the material forming the polymer homogeneous thin film layer are measured by a gas permeability measuring device manufactured by Yanagimoto Seisakusho. It was measured by a reduced pressure method at 25 ° C. using a dense film of a raw material polymer.

Example 1 Polysulfone (Udel-produced by Union Carbite Co.)
15% by weight of P3500) dimethylformamide (DM
F) The solution was made into a non-woven fabric composed of polyester fibers at a thickness of 50 μm at room temperature (MF-11 manufactured by Japan Vilene Co., Ltd.)
0, thickness 120 μm, weight 100 g / m ² ) and then the polysulfone is coagulated by immersing it in a coagulation tank filled with water to form a flat film of 160 μm thick polysulfone porous layer / polyester non-woven fabric. A composite membrane (A) was obtained.

2.0 g of polydimethylsiloxane having silanol groups at both ends (number average molecular weight of about 50,000), 0.4 g of tetrakis (2-propanone oxime) silane and 0.1 g of dibutyltin diacetate were added to trichlorotrifluoro. Dissolve in ethane to prepare a solution with a solid content of 0.5% by weight. A part of this dilute solution was coated on the membrane (A) whose surface was drained, dried by heating at 130 ° C. for 1 minute, and then dried at room temperature for 1 hour to form a crosslinked siloxane homogeneous thin film layer (thickness: about 0.1 μm). A flat film-like composite film (B) composed of / polysulfone porous layer / polyester nonwoven fabric was obtained. The oxygen permeation rate Q _O2 of this flat membrane composite membrane is 6 [m ³ / m ² · hr · atm]
And the oxygen / nitrogen permeation rate ratio α (= Q _O2 / Q _N2 ) was 2.0. The intrinsic oxygen / nitrogen permeation rate ratio α ^* of the crosslinked siloxane forming the thin film layer is 2.0 (oxygen permeation coefficient P _O2 is 5 × 10 ⁻⁸ [cm ³ · cm / cm ² · sec · cmH
g]), it was confirmed that a uniform thin film layer without defects was formed.

Test Method 1 As the alcohol-generating agent, the powder of Antimold 102 (manufactured by Freund Corporation) was used as the flat film-shaped composite film (A) of Example 1.
An alcohol generator was packaged in. Using this, castella was put in a polyethylene bag, and then an alcohol generator was put and sealed by heat sealing. In this state, no mold was found for 30 days.

Test method 2 As the oxygen absorbent of Example 1, 2.5 g of a composition of reduced iron powder / silica soil / saturated saline solution = 70/19/11 (weight ratio) was used. An oxygen absorber (a) having an effective area of 36 cm ² wrapped with a flat membrane composite membrane (B) was prepared. The oxygen absorber was sealed in a closed cell containing 100 ml of water and 200 ml of air in contact with water to absorb oxygen in the cell.

The oxygen concentration in the cell was measured by an oxygen concentration meter, and the oxygen absorption rate was calculated to be 130 ml / day, which confirmed that the oxygen absorber (a) had a high oxygen absorption capacity.

Further, the oxygen absorber (a) is sealed in a closed cell containing 100 ml of ultrapure water and 200 ml of air in a state of being in contact with water for 100 days, and the permeation state of water into the oxygen absorbent and the inside of the cell are The elution amount of the oxygen absorbent to water was analyzed. It was confirmed that water did not permeate into the oxygen absorbent, and that Fe, Si, and Cl in the water were analyzed by the plasma emission analysis method (ICAP method).

[0028]

INDUSTRIAL APPLICABILITY The present invention exhibits the following effects as a packaging sheet for a food preservative used for high-moisture foods, foods containing water drops and the like. In particular, the effect is remarkable when the system contains a liquid such as water, oil or alcohol or when long-term storage is required.

(1) Since it is a flat membrane composite membrane having a high gas permeation rate, it can quickly permeate oxygen, ethylene and the like in and around foods and can maintain high freshness by a food preservative.

(2) Since it is impermeable to water, it does not penetrate into food preservatives such as liquids, and it can be used for a long period of time even when applied to high-moisture foods and foods containing water droplets.

(3) There is no permeation into food preservatives such as liquids, and the air permeability of the packaging sheet does not deteriorate. (4) The food preservative such as liquid does not penetrate, and the food preservative does not elute.

(5) There is no permeation into food preservatives such as liquids, and the reaction between food preservatives and liquids does not cause a phenomenon such as an offensive odor.

(6) It can be easily processed by ordinary heat sealing or ultrasonic sealing, and there is no reduction in gas permeability due to deformation of the asymmetric porous layer or blockage of pores in the dense layer during processing.

Claims (5)

[Claims] 1. A sheet having an asymmetric porous layer having a dense layer formed on the surface and having a supporting layer made of a woven or non-woven fabric on the surface not having the dense layer, wherein the woven or non-woven fabric has a melting point of 100 ° C. As described above, a packaging sheet comprising a polymer component having a temperature of 170 ° C. or lower and having a heat distortion temperature of 170 ° C. or higher of a material forming the asymmetric porous layer. 2. The packaging sheet according to claim 1, wherein:
A packaging sheet having a space for accommodating a preservative on the support layer side. 3. The packaging sheet according to claim 1 or 2, further comprising a gas-permeable and water-impermeable polymer homogeneous layer on the dense layer side of the asymmetric porous layer. A wrapping sheet. 4. The packaging sheet according to claim 2, wherein the food preservative is arranged in a space for accommodating the preservative. 5. A packaging sheet, wherein the food preservative according to claim 4 is an oxygen absorbent, an alcohol generator, or an ethylene absorbent.