JPH08244157A - Gas barrier laminate containing paper - Google Patents

Abstract

PURPOSE: To form a laminate which can be burnt and of no gas barrier deterioration by laminating polymer plastic, a gas barrier layer composed of an inorganic oxide of specified thickness, an extrusion laminate plyolefin thermoplastic resin layer having specified melt flow rate and a paper in the above-said order. CONSTITUTION: A gas barrier laminate 1 containing paper is constituted of a deposit 3 composed of an inorganic oxide, polyolefin thermo-plastic resin 4 and a paper 5 placed on the surface of a polymer base 2. The inorganic deposit 3 is composed of deposit films constituted of silicon oxide, magnesium oxide, aluminum oxide and the like, and the thickness of lamination of the deposit 3 is preferably in the range of 30-300nm. A polyolefin thermoplastic resin layer 4 functions as a bonding layer when resin is melted into the shape of a curtain and stuck with the paper 5 at the time of extrusion lamination, and the melt flow rate is required to be 10(g/10min) or over.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging film used in the field of packaging foods, pharmaceuticals and the like, and in particular, a gas barrier having excellent easy-opening property by including paper and excellent in design such as appearance. Relating to a functional laminate.

[0002]

2. Description of the Related Art In recent years, packaging materials used for packaging foods, pharmaceuticals, etc. are used to suppress deterioration of contents, particularly oxidation and deterioration of proteins, fats and oils in foods, and to maintain taste and freshness. In addition, in the case of pharmaceuticals that require aseptic handling, it suppresses the deterioration of the active ingredient and prevents the effects of oxygen, water vapor, and other gases that modify the contents to permeate packaging materials to maintain efficacy. Therefore, it is required to have a gas barrier property of blocking gas such as these gases.

Further, among the above packaging materials, those which require easy opening, and those which require a good appearance for printing as an eye-catching effect for catching the eyes of the consumer, such as high-quality paper. There are many cases where paper is used.

Therefore, in order to satisfy the above items, a metal foil made of a metal such as Al is used as a gas barrier layer, and various polymer resin compositions having or not having a high gas barrier property alone contain Al or the like. A film having a structure in which a metal vapor-deposited film obtained by vapor-depositing a metal or a metal compound and a paper bonded together are used as a packaging material has been generally used.

However, a metal vapor-deposited film on which a foil or vapor-deposited film using a metal such as Al or a metal compound is formed,
Since it must be treated as an incombustible material when it is discarded after use, it has a drawback in that it is environmentally problematic.

Therefore, as a packaging material that overcomes these drawbacks, for example, US Pat.
Film in which a vapor deposition film is formed by a forming means such as a vacuum vapor deposition method or a sputtering method on a polymer film of an inorganic oxide such as silicon oxide, magnesium oxide, or aluminum oxide as described in JP-A-3-28017. Is being developed. Since these films have high gas barrier properties and can be incinerated, they are suitable as packaging materials.

[0007]

However, even films suitable for the above-mentioned packaging materials are rarely used as vapor-deposited films alone as packaging containers or packaging materials, and films or papers for use as packaging bags are rarely used. In most cases, it is used by being attached to a base material such as. In particular, it is often bonded to paper using an extrusion laminating method from the viewpoint of easy opening property and design.

[0008] Therefore, when laminated with paper under normal extrusion conditions (extrusion temperature: 320 ° C.), shrinkage of the paper during laminating and damage due to heat are transmitted to the vapor deposition film, causing damage such as cracks and scratches. There was a problem that the high gas barrier that it originally had deteriorated due to the penetration of gas such as oxygen and water vapor from the damaged part.

In view of the above, the present invention provides a gas barrier laminate comprising a highly practical paper which can be incinerated from the viewpoint of environment and is free from barrier deterioration due to lamination in a laminate obtained by laminating paper by an extrusion laminating method. The purpose is to provide.

[0010]

The present invention has been made to solve the above problems, and the invention described in claim 1 is a gas barrier made of a polymer plastic and an inorganic oxide having a thickness of 30 to 300 nm. A gas barrier laminate including a vapor deposition layer, an extrusion laminated polyolefin-based thermoplastic resin layer having a melt flow rate (hereinafter abbreviated as MFR) of 10 (g / 10 min) or more, and paper in which paper is laminated in this order. The invention described in claim 2 is the gas barrier laminate including the paper according to claim 1, wherein the inorganic oxide is silicon oxide, magnesium oxide, or aluminum oxide. The invention described in claim 3 is the gas barrier laminate including the paper according to claims 1 and 2, wherein the polyolefin-based thermoplastic resin is polyethylene. The invention described in claim 4 is the gas barrier laminate including the paper according to claim 3, wherein the extrusion temperature is 280 ° C. or lower. Further, the invention according to claim 5 is characterized in that at least one surface of the polyolefin-based thermoplastic resin is subjected to ozone treatment, and the gas barrier property including the paper according to claim 1, 2, 3, or 4. It is a laminated body. Further, the invention according to claim 6 is characterized in that the thickness of the polyolefin-based thermoplastic resin is 20 μm or less, and the gas barrier property including the paper according to claim 1, 2, 3, 4, or 5. It is a laminated body.

[0011]

According to the gas barrier laminate comprising the paper of the present invention, a film on which an inorganic oxide having an excellent gas barrier property is vapor-deposited is laminated by an extrusion laminating method. did it. Moreover, since the MFR is high, the shrinkage of the laminate may be small,
As a result, cracks do not occur in the vapor deposition film and the gas barrier property does not deteriorate. This effect is particularly remarkable at low temperatures.

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a gas barrier laminate including the paper of the present invention.

First, the structure of the gas barrier laminate 1 containing the paper of the present invention will be described with reference to FIG. Reference numeral 1 is a gas barrier laminate including paper, and a vapor deposition layer 3 made of an inorganic oxide, a polyolefin-based thermoplastic resin layer 4, and a paper 5 are sequentially formed on the surface of a polymer substrate 2.

The above-mentioned base material 2 is a polymer plastic material, and serves as a base material for vapor deposition. For example, polyethylene terephthalate (PET), polyester films such as polyethylene naphthalate, polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films, polyvinyl chloride films, polycarbonate films, polyacrylonitrile films, polyimide films, etc. are used, It may be stretched or unstretched, and one having mechanical strength and dimensional stability is preferable.

These are processed into a film and used. In particular, polyethylene terephthalate arbitrarily stretched biaxially is preferably used. In addition, various well-known additives and stabilizers such as antistatic agents, UV inhibitors, plasticizers and lubricants may be used on the surface of the base material 2 to improve the adhesion to the deposited film. Therefore, a corona treatment, a low temperature plasma treatment, an ion bombardment treatment may be performed as a pretreatment, and a chemical treatment or a solvent treatment may be further performed.

The thickness of the base material 2 is not particularly limited, but it is suitable as a packaging material, may be laminated with other layers, and has a processability when the inorganic oxide vapor deposition layer 3 is formed. In consideration of the above, it can be said that the thickness is practically in the range of 3 to 200 μm, and preferably 6 to 30 μm depending on the application.

In consideration of mass productivity, it is desirable to use a long film so that a thin film can be continuously formed.

The inorganic oxide vapor-deposited layer 3 is made of a vapor-deposited film of an inorganic oxide such as silicon oxide, magnesium oxide or aluminum oxide, and may have a gas barrier property against oxygen and water vapor. However, the vapor deposition layer 3 of the present invention is not limited to inorganic oxides such as silicon oxide, magnesium oxide, and aluminum oxide, and any material that meets the above conditions can be used.

The thickness of the vapor-deposited layer 3 varies depending on the type and composition of the inorganic oxide used, but generally 3
It is desirable to be in the range of 0 to 300 nm, and the value is appropriately selected. However, if the film thickness is less than 30 nm, the entire surface of the substrate 2 may not be a film or the film thickness may not be sufficient, and the gas barrier material may not be able to sufficiently function. Further, if the film thickness exceeds 300 nm, the thin film cannot retain flexibility, and cracks may occur in the thin film due to external factors such as bending and pulling after the film formation. It is preferably in the range of 40 to 150 nm.

There are various methods for forming the vapor deposition layer 3 made of an inorganic oxide on the polymer plastic substrate 2, and it can be formed by a usual vacuum vapor deposition method, but another method for forming a thin film is a sputtering method. Alternatively, the ion plating method or the like can be used. However, in view of productivity, the vacuum vapor deposition method is the best at the present time. As the heating means of the vacuum vapor deposition apparatus by the vacuum vapor deposition method, it is preferable to use an electron beam heating method or a resistance heating method, in order to improve the adhesion of the vapor deposition film and the base material and the denseness of the thin film,
It is also possible to use a plasma assist method or an ion beam assist method.

The polyolefin-based thermoplastic resin layer 4 is formed by melting the resin in a curtain shape during extrusion lamination to form the base material 2.
Which functions as an adhesive layer when the paper 5 and the paper 5 are bonded together,
MF in consideration of workability at low temperature by reducing shrinkage during lamination
R needs to be 10 (g / 10 min) or more. M
When the FR is less than 10 (g / 10 min), the low temperature processability is poor and the shrinkage during laminating is large, so that the vapor deposition film is cracked and the gas barrier property is deteriorated. Preferably, the MFR is in the range of 12 to 14 (g / 10 min).

As the polyolefin type thermoplastic resin,
For example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer and the like can be used, but polyethylene is the most preferable in view of extrusion processability.

The temperature at which the resin is melted and extruded in the shape of a curtain must be low enough to prevent the gas barrier properties of the inorganic oxide vapor deposition layer 2 from being thermally deteriorated. Optimum conditions vary depending on the resin, but in the case of polyethylene. Is preferably 280 ° C. or lower. If it exceeds 280 ° C, the vapor deposition film is damaged by heat and the gas barrier property is deteriorated. When the temperature is 250 ° C. or lower, it may be a problem in extrusion processing, so that it is preferably in the range of 260 to 280 ° C.

When the extrusion temperature is as low as 280 ° C. or lower, the natural oxidation that occurs during free fall from the T-die may become insufficient and the adhesive strength between the base material and the paper may be weakened. Therefore, it is necessary to forcibly oxidize in order to make up for this insufficient amount of oxidation, and it is necessary to use ozone treatment when performing extrusion lamination at the above temperature.

As the ozone treatment method, one surface of at least the molten resin is wiped with ozone to the extent that the temperature of the resin is not excessively lowered or vibrated. As a method of generating ozone, a known method may be used. For example, ozone can be easily generated by an electric discharge treatment of air in a closed container and can be quantitatively transported by a carrier gas.

The optimum thickness of the polyolefin thermoplastic resin varies depending on the resin composition, the extrusion temperature and the like, but when polyethylene is extrusion-laminated at a temperature of 280 ° C. or less, it should be 20 μm or less. Two
If the thickness exceeds 0 μm, the stress when the resin layer is cooled and cured becomes too large, and the strain is transmitted to the vapor deposition film, causing cracks. If it is 10 μm or less, it may cause a problem in extrusion processing, so that it is preferably 15 to 20 μm.
It is in the range of.

The paper 5 is used as a printing substrate for pasting together to give an unsealing property and for printing characters, pictures, drawings and the like on the front side. The type can be selected according to the intended function of the packaging material, the print pattern, etc., and for example, high-quality paper, kraft paper, coated paper, etc. can be used. The thickness can also be arbitrarily selected.

It is also possible to laminate another layer such as a heat seal layer on the side of the base material 2 opposite to the inorganic oxide vapor deposition layer 3. The heat-sealing layer is used for an adhesive part when forming a bag-like package, polyethylene,
Polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer and their metal crosslinked products, etc. Resin is used. Although the thickness is determined according to the purpose, it is generally in the range of 15 to 200 μm.
As a forming method, any of known methods such as a dry laminating method of laminating a film made of the above resin by a non-solvent laminating method, an extrusion laminating method in which the above resin is melted by heating and extruded in a curtain shape, and laminated It can be laminated.

The gas barrier laminate comprising the paper of the present invention will be further described with reference to specific examples.

Example 1 Magnesium oxide was vapor-deposited to a thickness of about 50 nm on one side of a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm as a base material 2 by a vacuum vapor deposition system by an electron beam heating system (not shown). Then, the inorganic oxide vapor deposition film layer 3 was formed. Then, this vapor-deposited film has an MFR of 14.0 using an extrusion laminating method.
Polyethylene 4 was heated and melted in a curtain shape at an extrusion temperature of 280 ° C. to a thickness of 15 μm, and a thickness of 52.
A gas barrier laminate 1 containing the paper of the present invention was obtained by sticking 3 g / m ² of high quality paper 5. Further, at this time, in order to forcibly oxidize, both surfaces of the resin melted in a curtain shape were subjected to ozone treatment.

Example 2 A gas barrier laminate 1 containing the paper of the present invention was obtained in the same manner as in Example 1 except that the extrusion temperature was 270 ° C.

Example 3 A gas barrier laminate 1 containing the paper of the present invention was obtained in the same manner as in Example 1 except that the thickness of polyethylene was 20 μm.

<Embodiment 4> MFR is 1 in Embodiment 1.
A gas barrier laminate 1 containing the paper of the present invention was obtained in the same manner except that polyethylene of 0.0 was used.

Example 5 A gas barrier laminate 1 containing the paper of the present invention was obtained in the same manner as in Example 1 except that the inorganic oxide layer 2 was provided with silicon oxide by a resistance heating method (not shown). .

Example 6 A gas barrier laminate 1 containing the paper of the present invention was prepared in the same manner as in Example 1 except that the inorganic oxide layer 2 was provided with aluminum oxide by an electron beam heating method (not shown). It was

Comparative Example 1 A laminate containing paper was prepared in the same manner as in Example 1 except that polyethylene having an MFR of 8.0 was used.

<Comparative Example 2> An aluminum foil having a thickness of 7 μm was used as a barrier layer, and the MFR was 5.0 by the extrusion laminating method.
Of polyethylene at a extrusion temperature of 310 ° C. is heated and melted in a curtain shape to a thickness of 15 μm, and a thickness of 52.3 g
A laminate including a high-quality paper // m ² and a laminated paper was obtained.

Even if the structure shown in claim 1 as described above is shown, a structure that particularly reduces the effect is possible, and it will be shown in the following reference example. This is a mistake in the selection of resin and vapor deposition film.

Reference Example 1 A laminate containing paper was prepared in the same manner as in Example 1 except that the extrusion temperature was 310 ° C. and no ozone treatment was performed.

Reference Example 2 A laminate containing paper was prepared in the same manner as in Example 1 except that the thickness of polyethylene was 30 μm.

Reference Example 3 A laminate containing paper was prepared in the same manner as in Example 1 except that the ozone treatment was not used.

In order to evaluate the obtained laminate, the water vapor permeability (g / m ² / day), the laminate strength (g / 1
5 mm) was measured. Also, the incineration property was confirmed from the environmental aspect. Table 1 shows the results.

[0043]

[Table 1]

In comparison with the example, the comparative example has a gas barrier property,
Although it does not satisfy all of the laminating strength and the incineration property, the gas barrier laminate containing the paper of the present invention satisfies all the above items.

In Reference Example 1, the effect of the present invention should be originally obtained. However, since the vapor deposition layer has a temperature higher than the heat-resistant temperature, the action of Claim 1 does not occur. This is an example in which the effect of the present invention is not exhibited due to another action. Even in such an example, the effect of the present invention can be achieved by providing an environment in which the action of the present invention is exhibited.

Reference example 2 should also have the effect of the present invention, but the selection of resin, temperature, and film thickness is wrong, and the stress of the resin layer becomes too large and the vapor deposition film is distorted. This is an example in which a crack is generated and the effect of the present invention is not exhibited due to an action different from the action of claim 1 despite the action of claim 1. Even in such an example, the effect of the present invention can be achieved by providing an environment in which the action of the present invention is exhibited.

Also, in Reference Example 3, the effect of the present invention should be obtained originally, but the selection of the resin and the temperature is wrong, the oxidation of the resin layer is not sufficient, and the adhesive strength is lowered. This is an example in which the effect of the present invention does not appear due to an effect different from the effect of claim 1 despite the effect of claim 1. Even in such an example, the effect of the present invention can be achieved by providing an environment in which the action of the present invention is exhibited.

[0048]

As described above, according to the gas barrier laminate including the paper of the present invention, a film obtained by vapor deposition of an incinerable inorganic oxide is used as the gas barrier layer, and the film and paper are extruded. Since it is laminated using a polyolefin-based thermoplastic resin that has a high MFR that does not cause cracks in the inorganic oxide vapor deposition layer when laminating and has little shrinkage during laminating, it has excellent gas barrier properties and is highly environmentally friendly and highly practical. A laminate is obtained.

[0049]

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a gas barrier laminate including the paper of the present invention.

[Explanation of symbols]

 1 Gas Barrier Laminate including Paper 2 Polymer Plastic Substrate 3 Inorganic Oxide Deposition Layer 4 Polyolefin Thermoplastic Resin 5 Paper

Claims (6)

[Claims] 1. Polymer plastic, thickness 30-300 n
A gas barrier layered product including a gas barrier vapor deposition layer composed of an inorganic oxide of m, an extrusion laminated polyolefin-based thermoplastic resin layer having a melt flow rate of 10 (g / 10 min) or more, and a paper in which papers are laminated in this order. 2. The gas barrier laminate containing paper according to claim 1, wherein the inorganic oxide is silicon oxide, magnesium oxide or aluminum oxide. 3. The gas barrier laminate comprising paper according to claim 1, wherein the polyolefin-based thermoplastic resin is polyethylene. 4. A gas barrier laminate comprising the paper according to claim 2, wherein the extrusion temperature is 280 ° C. or lower. 5. The gas barrier laminate comprising paper according to claim 1, wherein at least one surface of the polyolefin-based thermoplastic resin is oxidized. 6. The thermoplastic resin according to claim 1, wherein the thickness of the thermoplastic polyolefin resin is 20 μm or less.
A gas barrier laminate comprising the paper of 2, 3, 4, or 5.