WO2021010040A1

WO2021010040A1 - Paper layered product

Info

Publication number: WO2021010040A1
Application number: PCT/JP2020/021685
Authority: WO
Inventors: 泰友野一色; 友史磯▲崎▼; 正啓鶴原; 裕太社本
Original assignee: 王子ホールディングス株式会社
Priority date: 2019-07-12
Filing date: 2020-06-02
Publication date: 2021-01-21
Also published as: JPWO2021010040A1; JP7497730B2

Abstract

This paper layered product has, on at least one surface thereof, a deposition layer comprising metal or a ceramic having a thickness of 1-1000 nm, and further has, on the deposition layer, a resin layer comprising a thermoplastic resin having a thickness of not less than 1 μm but less than 15 μm.

Description

Paper laminate

The present invention relates to a paper laminate.

Packaging materials that have water vapor barrier properties and gas barrier properties (particularly oxygen barrier properties) added to the paper base material have been conventionally used in packaging foods, medical products, electronic parts, etc. in order to prevent deterioration of the quality of the contents. Has been done.

As a method for imparting water vapor barrier property or gas barrier property to the paper base material, a method of laminating a synthetic resin film having excellent gas barrier property on the paper base material is common. However, it is difficult to recycle paper, synthetic resin, etc. after use of a material in which a synthetic resin film or the like is laminated on a paper base material, which poses an environmental problem.
Therefore, the development of a barrier material that does not require laminating a synthetic resin film or the like has been promoted. For example, Patent Document 1 discloses a paper packaging material having an organic substance coating layer, a metal or metal oxide layer, and an organic substance coating layer inside the paper layer and having a barrier property against moisture and oxygen.

On the other hand, metal-deposited paper is widely used for label paper with excellent design such as sake, beer, and refreshing drinking water, wrapping paper for confectionery, etc. by taking advantage of its glossiness. Since it is necessary to form a thin film, improvement of its adhesiveness and a manufacturing method are being studied. For example, Patent Document 2 discloses an aluminum-deposited paper using a base paper in which an aluminum-deposited layer is provided on a base paper and the back surface is treated so that the natural polarization potential value of the surface of the vapor-deposited layer is within a specific range. There is.

JP-A-2002-321307 Japanese Unexamined Patent Publication No. 4-65599

Although attempts have been made to improve the barrier property of the paper base material by using a metal foil or a metal oxide foil as in Patent Document 1, in consideration of recyclability, flexibility, and the texture of the paper, it is like a vapor-deposited film. When a very thin film is formed, durability during use or processing becomes a problem. That is, when three-dimensional processing such as embossing or bending processing is performed, there is a problem that the barrier performance is deteriorated probably because the vapor-filmed film of metal or metal oxide is damaged such as cracks.
Therefore, an object of the present invention is to provide a paper laminate having excellent resistance to processing and high barrier performance.

As a result of diligent studies, the present inventors have found that a laminate having a metal or ceramic vapor-deposited layer having a specific thickness and a resin layer made of a thermoplastic resin having a specific thickness on a paper substrate has the above-mentioned problems. I found a solution.
That is, the present invention relates to the following <1> to <14>.
<1> A vapor-deposited layer made of a metal or ceramic having a thickness of 1 to 1000 nm is provided on at least one surface of a paper substrate, and a resin layer made of a thermoplastic resin having a thickness of 1 μm or more and less than 15 μm is further provided on the vapor-deposited layer. , Paper laminate.
<2> The paper laminate according to <1>, wherein the basis weight of the paper base material is 20 to 500 g / m ² .
<3> The paper laminate according to <1> or <2>, wherein the vapor-deposited layer is made of aluminum, silicon oxide, or aluminum oxide.
<4> The paper laminate according to any one of <1> to <3>, wherein the thermoplastic resin constituting the resin layer is a heat-sealable resin.
<5> The thermoplastic resin is at least one selected from olefin / unsaturated carboxylic acid copolymers, biodegradable resins, polyethylene, polypropylene, acrylic resins, and ethylene vinyl alcohols, <1> to < The paper laminate according to any one of 4>.
<6> One or more of the biodegradable resins selected from polylactic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, and poly (3-hydroxybutyrate-co-hydroxyhexanoate). The paper laminate according to <5>.
<7> The paper laminate according to any one of <1> to <6>, which has one or more selected from a clay coat layer and an undercoat layer between the paper base material and the thin-film deposition layer. ..
<8> A clay coat layer and an undercoat layer are provided between the paper substrate and the vapor deposition layer, and an undercoat layer is provided between the clay coat layer and the vapor deposition layer. The paper laminate according to any one of <7>.
<9> The undercoat layer is composed of a resin binder, and the resin contained in the resin binder is at least one selected from polyvinyl alcohol, ethylene-modified polyvinyl alcohol, acrylic resin, polyurethane resin, and polyester resin. <7> Or the paper laminate according to <8>.
<10> The paper laminate according to any one of <1> to <9>, wherein the resin layer is the outermost layer.
<11> The paper laminate according to any one of <1> to <10>, wherein the paper base material is the outermost layer.
<12> The paper laminate according to any one of <1> to <11>, wherein the thickness of the resin layer is 3 to 7 μm.
<13> The paper laminate according to any one of <1> to <12>, wherein the thermoplastic resin is at least one selected from an olefin / unsaturated carboxylic acid-based copolymer and polylactic acid.
<14> A resin solution or a resin dispersion is applied to a vapor-deposited paper having a vapor-deposited layer made of a metal or ceramic having a thickness of 1 to 1000 nm on at least one surface of a paper base material, dried, and has a thickness of 1 μm or more and less than 15 μm. A method for producing a paper laminate, which comprises a step of forming a resin layer made of the thermoplastic resin of the above.

In the present specification, the numerical range represented by "XY" means X or more and Y or less.
[Paper laminate]
The paper laminate according to the embodiment of the present invention has a thin-film deposition layer made of a metal or ceramic having a thickness of 1 to 1000 nm on at least one surface of the paper base material, and further has a thickness of 1 μm or more and less than 15 μm on the thin-film deposition layer. It has a resin layer made of the thermoplastic resin of. The paper laminate has excellent resistance to processing of the present invention and has high barrier performance.
The paper laminate according to the embodiment of the present invention has a high barrier property by having a vapor-deposited layer, and by having a resin layer, the vapor-deposited layer is protected even by deformation of the paper during processing to provide a barrier property. In addition to being able to be maintained, heat-sealing properties can also be imparted depending on the resin constituting the resin layer. In addition, since it is possible to prevent damage to the thin-film deposition layer having a glossy feeling, it is also excellent in designability.

The paper substrate may have a thin-film deposition layer on one side or both sides, but it is preferable to have a thin-film deposition layer on one side from the viewpoint of production efficiency. In the present invention, even if the vapor deposition layer is provided on only one side, sufficient barrier properties can be exhibited. When the vapor deposition layer is provided on one side, it is preferable to have the resin layer only on the vapor deposition layer side.
When a vapor-deposited layer is provided on one side from the viewpoint of production efficiency, it is preferable that the paper base material is the outermost layer in the paper laminate of the present invention.
When the vapor deposition layer is provided on both sides, it is preferable to have a resin layer made of a thermoplastic resin on one side or both sides thereof, and particularly preferably to have a resin layer made of a thermoplastic resin on one side.
By having a resin layer made of a thermoplastic resin on one side, the production efficiency is excellent, and when the laminate of the present invention is heat-sealed, a bag-shaped product or the like can be easily produced.
The resin layer is preferably formed directly on the vapor-deposited layer. Since the resin layer is formed directly on the vapor-deposited layer, the resin layer can efficiently protect the vapor-deposited layer from damage due to deformation during processing.

<Paper base material>
The paper base material used in the paper laminate of the present invention is preferably a commonly used paper containing plant-derived pulp as a main component, and more preferably a paper containing wood pulp as a main component. preferable. Further, it is preferable that the paper is mainly composed of pulp which is easily dispersed in water by a mechanical dissociation action.
Specific examples include bleached kraft paper, unbleached kraft paper, high-quality paper, paperboard, liner paper, coated paper, single-gloss paper, glassin paper, graphan paper, etc. Among these, bleached kraft paper and unbleached paper. Kraft paper, high-quality paper, and single-gloss paper are preferable.

The dissociation freeness (degree of drainage) measured according to JIS P8121: 2012 of the paper base material is preferably 800 ml or less, more preferably 500 ml or less, from the viewpoint of improving the barrier property. Here, the dissociation freeness is a Canadian standard drainage degree (Canadian standard freedom) measured in accordance with JIS P8121: 2012 for pulp obtained by dissociating the paper after papermaking in accordance with JIS P8220-1. .. As a method for beating the pulp to adjust the disintegration freeness, a known method can be used.

The size of the paper base material is not particularly limited, but from the viewpoint of improving the barrier property, it is preferable that the size of the stechhito according to JIS P8122: 2004 is 1 second or more. The size of the paper substrate can be controlled by the type and content of the internal sizing agent, the type of pulp, the smoothing treatment, and the like.
Examples of the internal sizing agent include rosin type, alkyl ketene dimer type, alkenyl succinic anhydride type, styrene-acrylic type, higher fatty acid type, petroleum resin type and the like. The content of the internal sizing agent is preferably 3 parts by mass or less with respect to 100 parts by mass of the pulp of the paper base material.

In addition to the internal sizing agent, other known internal additives may be added to the paper substrate. Internal additives include fillers, paper strength enhancers, yield improvers, pH adjusters, drainage improvers, water resistant agents, fabric softeners, antistatic agents, defoamers, slime control agents, dyes / pigments, etc. Can be mentioned.
Examples of the filler include titanium dioxide, kaolin, talc, calcium carbonate and the like.

For paper making of a paper base material, a known wet paper machine can be appropriately selected and used.
Examples of the paper machine include a long net paper machine, a gap former type paper machine, a circular net type paper machine, and a short net type paper machine.
The paper layer formed by the paper machine is preferably conveyed by, for example, felt and dried by a dryer. A multi-stage cylinder dryer may be used as a pre-dryer before drying the dryer.

Further, the paper base material obtained as described above may be surface-treated with a calendar to make the thickness and profile uniform. As the calendar processing, a known calendar processing machine can be appropriately selected and used.

The basis weight of the paper substrate is preferably 20 ~ 500g / m ^2, more preferably 20 ~ 400g / m ^2, more preferably 20 ~ 200g / m ^2, even more preferably from 30 ~ 100g / m ² ..
The paper substrate, from the viewpoint of moldability, it is preferable that a density of 0.5 ~ 1.2g / cm ^3, more preferably 0.6 ~ 1.0g / cm ^3.
From the viewpoint of obtaining a uniform thin-film deposition layer, the paper base material preferably has a Wangken-type smoothness of at least the surface on which the vapor-film deposition layer is provided, preferably 5 seconds or more, and more preferably 10 to 1000 seconds. From the viewpoint of printability, the paper base material preferably has a 75 ° glossiness of 5% or more, and more preferably 10 to 70%.

<Thin-film deposition layer>
The vapor-deposited layer used in the paper laminate of the present invention is made of a metal or ceramic having a thickness of 1 to 1000 nm.
The thickness of the thin-film deposition layer is 1 to 1000 nm, preferably 2 to 500 nm, and more preferably 3 to 100 nm. From the viewpoint of barrier property, 10 to 80 nm is more preferable, and 25 to 70 nm is even more preferable. Further, from the viewpoint of adhesion to other layers and cost, 4 to 100 nm is preferable, 4 to 70 nm is more preferable, 4 to 50 nm is further preferable, 5 to 50 nm is further preferable, and even if it is, for example, 5 to 30 nm. Good.

The vapor deposition layer is made of metal or ceramic, preferably metal.
When the vapor-deposited layer is a metal, specific examples thereof include aluminum and titanium, and aluminum is preferable.
When the vapor-deposited layer is ceramic, specific examples thereof include silicon oxide, titanium oxide and aluminum oxide, and silicon oxide or aluminum oxide is preferable.
That is, the vapor-deposited layer is more preferably made of aluminum, silicon oxide or aluminum oxide, and aluminum is even more preferable.

<Resin layer>
The paper laminate of the present invention has a resin layer made of a thermoplastic resin having a thickness of 1 μm or more and less than 15 μm.
The thickness of the resin layer is 1 μm or more and less than 15 μm, preferably 2 to 10 μm, and more preferably 3 to 7 μm.
When the thickness of the resin layer is 1 μm or more and less than 15 μm, the paper is excellent in disintegration property at the time of recycling and is also excellent in recyclability while maintaining excellent protection against the vapor-deposited layer. Further, when the thickness of the present resin layer is 1 μm or more and less than 15 μm, the paper laminate also has excellent heat-sealing properties.
Further, in the paper laminate of the present invention, the resin layer is preferably the outermost layer. Since the resin layer is the outermost layer, the resin layer can be imparted with heat-sealing properties to form a container. Furthermore, since it is not affected by other layers, it is easy to protect the vapor-deposited layer from external forces due to deformation. Moreover, it does not impair the design of the vapor-deposited layer having a glossy feeling.

The resin constituting the resin layer is a thermoplastic resin from the viewpoint of facilitating the formation of the resin layer, improving the protection of the vapor-deposited layer, and imparting heat-sealing property.
The thermoplastic resin is preferably one or more selected from olefin / unsaturated carboxylic acid-based copolymers, biodegradable resins, polyethylene, polypropylene, acrylic resins, and ethylene vinyl alcohols, and among them, olefins. More preferably, it is one or more selected from an unsaturated carboxylic acid-based copolymer, a biodegradable resin, and an acrylic resin, and one selected from an olefin / unsaturated carboxylic acid-based copolymer and a biodegradable resin. The above is more preferable, and more specifically, one or more selected from an olefin / unsaturated carboxylic acid-based copolymer and polylactic acid is more preferable. From the viewpoint of protecting the vapor-filmed layer, an olefin / unsaturated carboxylic acid-based copolymer is further preferable, and from the viewpoint of recyclability and reduction of environmental load, a biodegradable resin is further preferable.

As the olefin / unsaturated carboxylic acid-based copolymer, an ethylene / acrylic-based copolymer is preferable. Since the ethylene / acrylic copolymer is highly available and can be synthesized as an aqueous dispersion, a resin layer can be easily formed on the vapor-deposited layer by coating and drying, which is preferable.
When an olefin / unsaturated carboxylic acid-based copolymer is used as an aqueous dispersion, the unsaturated carboxylic acid or acrylic monomer component may be an alkali metal hydroxide, ammonia, alkylamine, alkanolamine or the like. It is preferably a salt that is partially or completely neutralized.

When an olefin / unsaturated carboxylic acid-based copolymer is used, the content of the olefin / unsaturated carboxylic acid-based copolymer in the resin layer is preferably 20% by mass or more, preferably 50% by mass or more, based on the total solid content of the resin layer. Is more preferable, 60% by mass or more is further preferable, 70% by mass or more is further preferable, 80% by mass or more is further preferable, 90% by mass or more is particularly preferable, and 95% by mass or more is most preferable. The upper limit is not particularly limited, but is preferably 100% by mass or less.

Examples of the acrylic monomer constituting the ethylene / acrylic copolymer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, silicic acid, itaconic acid, fumaric acid, maleic acid, and butentricarboxylic acid. Unsaturated polycarboxylic acid alkyl ester having at least one carboxyl group, such as itaconic acid monoethyl ester, fumaric acid monobutyl ester and maleic acid monobutyl ester, acrylamide propane sulfonic acid, acrylic acid sulfoethyl sodium salt, methacrylic acid Examples thereof include unsaturated sulfonic acid monomers such as sulfopropyl sodium salts or salts thereof, preferably unsaturated carboxylic acids, more preferably acrylic acid and methacrylic acid, and even more preferably acrylic acid.
The acrylic monomer constituting the ethylene / acrylic copolymer may be one kind or a combination of two or more kinds.

The ethylene / acrylic copolymer is preferably obtained by emulsion polymerization of ethylene and the acrylic monomer. As the ethylene / acrylic copolymer, an ethylene / acrylic acid copolymer and an ethylene / methacrylic acid copolymer are preferable. As long as the effects of the present invention are not impaired, the copolymer may be copolymerized with a monomer composed of ethylene and other compounds copolymerizable with the acrylic monomer.

The content of the acrylic monomer unit in the ethylene / acrylic copolymer (copolymerization ratio of the acrylic monomer) is preferably 1 to 50 mol%, more preferably 10 to 30 mol%. When the ethylene / acrylic copolymer contains an acrylic acid unit as an acrylic monomer unit, the content of the acrylic acid unit (copolymerization ratio of acrylic acid) is preferably 1 to 50 mol%, and 10 to 30. More preferably mol%. When the content of the acrylic monomer unit is 1 to 50 mol%, the melting temperature is 60 to 120 ° C., and an excellent ethylene / acrylic copolymer exhibiting good heat sealability is obtained.

The weight average molecular weight of the ethylene / acrylic copolymer is preferably 10,000 to 10 million, more preferably 100,000 to 5 million, from the viewpoint of the viscosity of the coating liquid and the strength of the coating film.

Specific examples of the ethylene / acrylic copolymer include Zyxen (registered trademark) AC (aqueous dispersion of ethylene / acrylic acid copolymer ammonium salt, acrylic acid copolymerization ratio of 20 mol%, manufactured by Sumitomo Seika Co., Ltd.). ) Etc. can be mentioned.

Biodegradable resins include polylactic acid (PLA), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), and poly (3-hydroxybutyrate-co-hydroxy). It is preferably one or more selected from (hexanoate) (PHBH), more preferably one or more selected from polylactic acid and polybutylene succinate, and even more preferably polylactic acid. Packaging materials using a paper base material have the advantage of reducing the environmental load as compared with packaging materials made of a resin film. However, by using a biodegradable resin as the resin layer of the present invention, The environmental load can be further reduced.

As the biodegradable resin, it is preferable to use an aqueous dispersion from the viewpoint of facilitating coating and reducing the burden on the environment, and more preferably to use an aqueous dispersion of polylactic acid from the viewpoint of availability. ..
Specific examples of polylactic acid include Randy PL-1000 and Randy PL-3000 (aqueous dispersion of polylactic acid, manufactured by Miyoshi Oil & Fat Co., Ltd.).

The thermoplastic resin used for the resin layer constituting the paper laminate of the present invention is preferably heat-sealable. Therefore, when the resin constituting the resin layer has a melting point, the melting point is preferably 60 to 120 ° C., more preferably 70 to 110 ° C., and even more preferably 80 to 100 ° C.
Since the resin layer can be heat-sealed, a packaging bag or the like made of only the paper laminate of the present invention can be easily obtained. Further, by fusing it to another sheet, film, container or the like, the paper laminate can be used as the main body of the packaging container, the lid of the packaging container or the like. The packaging bag and packaging container thus obtained have excellent barrier properties.

The tensile strength of the thermoplastic resin is preferably 5 to 30 MPa, more preferably 10 to 20 MPa. Tensile strength is measured according to JIS K7161.
The elongation at the breaking point of the thermoplastic resin is preferably 200 to 600%, more preferably 300 to 500%. Break point elongation is measured according to JIS K7161.

The resin layer constituting the paper laminate of the present invention is made of a thermoplastic resin, but other resins and additives can be contained as long as the effects of the present invention are not impaired.
That is, when the resin layer is "consisting of a thermoplastic resin", it means that the main component of the resin layer is a thermoplastic resin, and the content of the thermoplastic resin in the resin layer is preferably 80% by mass or more. Yes, more preferably 90% by mass or more, further preferably 95% by mass or more, still more preferably 99% by mass or more.
Additives can include surfactants, pigments, antioxidants, antistatic agents, dyes, plasticizers, lubricants, mold release agents and the like. When the resin is used as an aqueous dispersion, it is preferable to use a dispersant in order to disperse the resin in an aqueous medium and obtain a uniform resin layer film.

<Arbitrary layer>
The paper laminate of the present invention may contain any layer in addition to the paper base material, the vapor-deposited layer, and the resin layer. Optional layers include clay coat layers and undercoat layers. The paper laminate of the present invention preferably has one or more selected from a clay coat layer and an undercoat layer between the paper base material and the thin-film deposition layer.
That is, in the paper laminate of the present invention, each layer is laminated in the order of clay coat layer, vapor deposition layer, and resin layer on at least one surface of the paper base material, or the undercoat layer and vapor deposition are formed on at least one surface of the paper base material. It is preferable that each layer is laminated in the order of the layer and the resin layer.
Further, it is more preferable that the paper laminate of the present invention has both a clay coat layer and an undercoat layer between the paper base material and the vapor-deposited layer. It is more preferable to have an undercoat layer between the vapor deposition layer.
That is, in the paper laminate of the present invention, it is more preferable that each layer is laminated in the order of the clay coat layer, the undercoat layer, the vapor deposition layer, and the resin layer on at least one surface of the paper base material.

(Clay coat layer)
The clay coat layer is preferably provided in the paper laminate from the viewpoint of sealing and smoothing the paper base material. As described above, in the paper laminate of the present invention, the clay coat layer is provided on the paper base. It is preferably held between the material and the vapor-deposited layer, and more preferably between the paper substrate and the undercoat layer.

The clay coat layer is mainly composed of clay and a binder. In addition, "the clay coat layer is mainly composed of clay and a binder" means that the total content of clay and a binder in the undercoat layer is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably. It means that it is 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The upper limit is not particularly limited, but is preferably 100% by mass or less. The clay coat layer may further contain any component in addition to the clay and the binder.
The clay contained in the clay coat layer is not particularly limited, and examples thereof include kaolin, talc, and mica. The aspect ratio of the clay is preferably 10 or more, more preferably 20 or more, and even more preferably 30 or more. The upper limit is not particularly limited, but is preferably 10,000 or less. The aspect ratio can be measured by observation with an electron microscope or X-ray diffraction measurement. The clay content in the clay coat layer is preferably 50 to 98% by mass, more preferably 60 to 90% by mass, and further preferably 70 to 85% by mass.
The binder contained in the clay coat layer is not particularly limited, and examples thereof include acrylic resin, styrene-butadiene resin, styrene-acrylic copolymer, ethylene-acrylic copolymer, and the like, and acrylic resin and styrene-acrylic. Copolymers are preferred. The content of the binder in the clay coat layer is preferably 2 to 50% by mass, more preferably 10 to 40% by mass, and further preferably 15 to 30% by mass.
The amount of the clay coat layer applied is not particularly limited, but the solid content is preferably 5 to 30 g / m ² , and more preferably 7 to 20 g / m ² .
The method for forming the clay coat layer is not particularly limited, but a method of forming a dispersion liquid containing clay and a resin binder by applying it on a paper substrate and drying it is preferable.
As the dispersion liquid containing the clay and the resin binder, an aqueous dispersion liquid is preferable.

(Undercoat layer)
The undercoat layer is preferably provided in the paper laminate from the viewpoint of enhancing the adhesiveness between the paper base material and the vapor-deposited layer. As described above, in the paper laminate of the present invention, the undercoat layer is provided on the paper base. It is preferably held between the material and the thin-film deposition layer, and more preferably between the clay coat layer and the thin-film deposition layer.

The undercoat layer is mainly composed of a binder. In addition, "the undercoat layer is mainly composed of a binder" means that the binder content in the undercoat layer is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and further. It means that it is preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more (upper limit 100% by mass). In addition to the binder, the undercoat layer may further contain any component.
The binder contained in the undercoat layer is not particularly limited, and examples thereof include an alkyd resin, an acrylic resin, a vinyl resin, a cellulosic resin, a urethane resin, and a polyester resin. Among them, one or more selected from polyvinyl alcohol resin, ethylene-modified polyvinyl alcohol, acrylic resin, urethane resin and polyester resin is more preferable, and one or more selected from polyvinyl alcohol resin and urethane resin. More preferably, a polyvinyl alcohol resin is further preferable from the viewpoint of oxygen barrier property.
The amount of the undercoat layer applied is not particularly limited, but the solid content is preferably 1 to 10 g / m ² , and more preferably 1 to 5 g / m ² .
The method for forming the undercoat layer is not particularly limited, but it is preferable to apply an aqueous solution of a binder or an aqueous dispersion and dry it to form the undercoat layer.

[Manufacturing method of paper laminate]
The method for producing the paper laminate of the present invention is not limited, but a resin solution or a resin dispersion is applied to a vapor-deposited paper having a vapor-deposited layer made of a metal or ceramic having a thickness of 1 to 1000 nm on at least one surface of a paper base material. It is preferable to have a step of working and drying to form a resin layer made of a thermoplastic resin having a thickness of 1 μm or more and less than 15 μm.

The vapor-deposited paper used in the production method of the present invention is preferably obtained by depositing a metal or ceramic on the paper substrate.
As described above, a clay coat layer may be provided on the surface of the paper substrate. The clay used for the clay coat layer is not particularly limited, and examples thereof include kaolin. The binder is not particularly limited, and examples thereof include an acrylic resin, a styrene-butadiene polymer, and a styrene-acrylic copolymer. When the clay coat layer is provided, it is preferable to form it by applying a dispersion liquid containing a clay and a binder on a paper substrate and drying it as described above.

Further, an undercoat layer may be provided on the surface of the paper base material as described above. The undercoat layer is preferably made of a binder such as an alkyd resin, an acrylic resin, a vinyl resin, a cellulose resin, a urethane resin, and a polyester resin. Among them, the binder is polyvinyl alcohol or ethylene-modified polyvinyl alcohol. , Acrylic resin, urethane resin, polyester resin are more preferable. When the undercoat layer is provided, it is preferable to apply an aqueous solution of a binder or an aqueous dispersion and dry it to form the undercoat layer.

As a method of depositing a metal or ceramic on a paper substrate, a method of vacuum-depositing the metal or ceramic directly on the surface of the paper substrate or the undercoat layer is preferable.
Examples of the metal or ceramic used here include aluminum, silicon oxide, and aluminum oxide, and aluminum is preferable from the viewpoint of cost and appearance.

Next, a resin layer made of a thermoplastic resin having a thickness of 1 μm or more and less than 15 μm is formed on the thin-film film.
It is preferable to form the resin layer directly on the thin-film layer of the thin-film film from the viewpoint of efficiently protecting the thin-film layer and enhancing the barrier property.
As a method for forming the resin layer, it is preferable to apply a resin solution or a resin dispersion liquid and dry the resin layer.
By using a method of forming a resin layer by applying a resin solution or a resin dispersion liquid, a resin layer having a relatively thin film of less than 15 μm can be formed. By forming such a relatively thin resin layer, it is possible to impart excellent disintegration property to the obtained paper laminate, and it is possible to obtain a laminate having excellent recyclability.

The resin used here is preferably a resin preferably used for the above-mentioned resin layer, and is an olefin / unsaturated carboxylic acid-based copolymer, a biodegradable resin, polyethylene, polypropylene, an acrylic resin, and ethylene vinyl. It is preferably one or more selected from alcohols, and more preferably one or more selected from olefin / unsaturated carboxylic acid copolymers, biodegradable resins, and acrylic resins. It is more preferable that the amount is one or more selected from the unsaturated carboxylic acid-based copolymer and the biodegradable resin.

These resins are coated on the vapor-deposited paper as a resin solution or a resin dispersion.
Examples of the resin solution or resin dispersion used here include a solution using an organic solvent that dissolves the resin, a dispersion using an organic solvent that disperses the resin, and a dispersion using an aqueous medium. A dispersion using an aqueous medium is preferable from the viewpoint of environmental load and environmental load. Of these, it is more preferable to use an aqueous dispersion of an olefin / unsaturated carboxylic acid-based copolymer, a biodegradable resin, and an acrylic resin.

Examples of the method for applying the resin solution or the resin dispersion include the bar coating method, the blade coating method, the squeeze coating method, the air knife coating method, the roll coating method, the gravure coating method, the transfer coating method, and the fountain coater. A coating machine such as a slit die coater may be used.
The coated coated vapor-deposited paper is dried to remove an organic solvent or an aqueous medium, and a paper laminate having a resin layer made of a thermoplastic resin on the vapor-deposited layer can be obtained.

The features of the present invention will be described in more detail below with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

[Example 1]
[Manufacturing of paper laminate (1)]
Aqueous dispersion of ethylene / acrylic acid copolymer ammonium salt (effective content 29.2% by mass, Zyxen AC, acrylic acid copolymer ratio 20 mol%, manufactured by Sumitomo Seika Co., Ltd.) has an effective content of 20% by mass. It was diluted with water so as to be a resin layer paint.
Using Mayer Bar (No. 16), the paint of the resin layer is applied to aluminum-deposited paper (base paper (paper base material) basis weight 60 g / m ² , aluminum-deposited layer 20 nm, manufactured by Oji F-Tex Co., Ltd.). , 120 ° C. for 1 minute to obtain a paper laminate (1). The thickness of the resin layer was 5 μm. The above-mentioned aluminum-deposited paper is obtained by laminating a clay coat layer, an undercoat layer, and a vapor-deposited layer in this order on a base paper (paper base material).
The evaluation results of the obtained paper laminate (1) are shown in Table 1.

[Example 2]
[Manufacturing of paper laminate (2)]
An aqueous dispersion of polylactic acid resin (effective content 40% by mass, Randy PL-3000, manufactured by Miyoshi Oil & Fat Co., Ltd.) was diluted with water so that the effective content was 20% by mass to prepare a paint for the resin layer.
Using Mayer Bar (No. 16), the paint of the resin layer is applied to aluminum-deposited paper (base paper (paper base material) basis weight 60 g / m ² , aluminum-deposited layer 20 nm, manufactured by Oji F-Tex Co., Ltd.). , 120 ° C. for 1 minute to obtain a paper laminate (2). The thickness of the resin layer was 6 μm.
The evaluation results of the obtained paper laminate (2) are shown in Table 1.

[Comparative Example 1]
The same evaluation as in Examples 1 and 2 using the aluminum-deposited paper (base paper (paper base material) basis weight 60 g / m ² , aluminum-deposited layer 20 nm, manufactured by Oji F-Tex Co., Ltd.) used in Examples 1 and 2 as it is. Was done. The evaluation results are shown in Table 1.

[Example 3]
[Manufacturing of paper laminate (3)]
80 parts by mass of kaolin (Contour Xtreme manufactured by Imeris, aspect ratio 33) and 20 parts by mass (solid content) of a styrene-acrylic copolymer binder (JONCRYL HSL-9012 manufactured by BASF) are mixed and used for a clay coat layer. A coating solution was prepared. Katatsuyashi (Oji Materia Corp., basis weight 65 g / m ^2, a thickness of 62 .mu.m, density 0.76 g / m ^3, the one surface Oken type smoothness of 427 seconds, Oken type smoothness of the second surface The clay coat layer coating solution was coated on a surface having a smoothness of 17 seconds by Oken (17 seconds), and dried at 120 ° C. for 1 minute to form a clay coat layer (10 g / m ² ). Formed. Next, a urethane resin binder (Takelac WPB-341 manufactured by Mitsui Chemicals Co., Ltd.) was coated on the clay coat layer with a Mayer bar and dried at 120 ° C. for 1 minute to form an undercoat layer (2 g / m ² ). did. Next, an aluminum-deposited layer (thickness 50 nm) was formed on the undercoat layer to obtain an aluminum-deposited paper.
Using the Mayer bar (No. 16), the paint of the resin layer produced in Example 1 was applied to the aluminum-deposited paper and dried at 120 ° C. for 1 minute to obtain a paper laminate (3). The thickness of the resin layer was 5 μm.
Table 2 shows the evaluation results of the obtained paper laminate (3).

[Example 4]
[Manufacturing of paper laminate (4)]
80 parts by mass of kaolin (Contour Xtreme manufactured by Imeris, aspect ratio 33) and 20 parts by mass (solid content) of a styrene-acrylic copolymer binder (JONCRYL HSL-9012 manufactured by BASF) are mixed and used for a clay coat layer. A coating solution was prepared. Katatsuyashi (Oji Materia Corp., basis weight 65 g / m ^2, a thickness of 62 .mu.m, density 0.76 g / m ^3, the one surface Oken type smoothness of 427 seconds, Oken type smoothness of the second surface The clay coat layer coating solution was coated on a surface having a smoothness of 17 seconds by Oken (17 seconds), and dried at 120 ° C. for 1 minute to form a clay coat layer (12 g / m ² ). Formed. Next, a polyvinyl alcohol resin binder (EXCEVAL AQ-4104 manufactured by Kuraray) was coated on the clay coat layer with Mayer bar and dried at 120 ° C. for 1 minute to form an undercoat layer (3 g / m ² ). .. Next, an aluminum-deposited layer (thickness 50 nm) was formed on the undercoat layer to obtain an aluminum-deposited paper.
Using the Mayer bar (No. 16), the paint of the resin layer produced in Example 1 was applied to the aluminum-deposited paper and dried at 120 ° C. for 1 minute to obtain a paper laminate (4). The thickness of the resin layer was 5 μm.
Table 2 shows the evaluation results of the obtained paper laminate (4).

[Evaluation]
[Oxygen permeability]
Using an oxygen permeability measuring device (OX-TRAN2 / 20 manufactured by MOCON), measure the oxygen permeability of the paper laminate and vapor-deposited paper under the conditions of temperature 23 ° C and relative humidity 50% (low humidity condition). did. The lower the value of oxygen permeability, the better the oxygen barrier property.
In addition, as an evaluation of processing resistance, oxygen permeability after bending was also measured. The folding method is as follows: the paper laminate or the vapor-deposited paper is folded once (fold angle 180 °) and then opened, and then re-folded along a line perpendicular to the folding line (fold angle 180 °) and then opened, and the oxygen permeability is described. The oxygen permeability was measured so that the intersection of the polygonal lines came to the center of the measuring section of the measuring device.

[Water vapor permeability]
In accordance with JIS Z0208 (cup method) B method (temperature 40 ° C ± 0.5 ° C, relative humidity 90% ± 2%), the resin layer of the paper laminate and the vapor-deposited paper should come to the inside (low humidity side). The water vapor permeability was measured. The lower the value of water vapor permeability, the better the water vapor barrier property.
In addition, as an evaluation of processing resistance, the water vapor permeability after bending was also measured. The folding method is as follows: once the paper laminate or vapor-deposited paper is folded (fold angle 180 °), it is opened, and then it is folded again along a line perpendicular to the line (fold angle 180 °), and then opened at the center of the measuring section. The water vapor permeability was measured so that the intersection of the polygonal lines would come.

[Heat sealability]
Two laminated bodies of each example or two thin-film vapor deposition papers of the comparative example are laminated so that the resin layer or the vapor-deposited layer faces each other, and the temperature is 130 ° C. using a heat seal tester (TP-701-B, manufactured by Tester Sangyo). Heat-sealing was performed under the conditions of 0.5 MPa and 30 seconds, and the heat-sealing property was evaluated. Those that were fused and heat-sealed were marked with 〇, and those that were not heat-sealed were marked with x.

In the paper laminate of the example, both the oxygen permeability and the water vapor permeability were maintained at low values even after bending as compared with the vapor-deposited paper of the comparative example, and the paper laminate was bent when used for a packaging bag or a packaging container. Even so, it can be seen that a high barrier property can be maintained.

Claims

A paper laminate having a vapor-deposited layer made of a metal or ceramic having a thickness of 1 to 1000 nm on at least one surface of a paper base material, and further having a resin layer made of a thermoplastic resin having a thickness of 1 μm or more and less than 15 μm on the vapor-deposited layer. body.
The paper laminate according to claim 1, wherein the paper substrate has a basis weight of 20 to 500 g / m 2 .
The paper laminate according to claim 1 or 2, wherein the vapor-deposited layer is made of aluminum, silicon oxide, or aluminum oxide.
The paper laminate according to any one of claims 1 to 3, wherein the thermoplastic resin constituting the resin layer is a heat-sealable resin.
Any one of claims 1 to 4, wherein the thermoplastic resin is at least one selected from an olefin / unsaturated carboxylic acid-based copolymer, a biodegradable resin, polyethylene, polypropylene, an acrylic resin, and an ethylene vinyl alcohol. The paper laminate according to one.
The biodegradable resin is one or more selected from polylactic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, and poly (3-hydroxybutyrate-co-hydroxyhexanoate). , The paper laminate according to claim 5.
The paper laminate according to any one of claims 1 to 6, which has one or more selected from a clay coat layer and an undercoat layer between the paper base material and the thin-film deposition layer.
7. The paper laminate according to one.
The undercoat layer is mainly composed of a binder, and the resin contained in the binder is at least one selected from polyvinyl alcohol, ethylene-modified polyvinyl alcohol, acrylic resin, polyurethane resin and polyester resin, according to claim 7 or 8. The paper laminate described.
The paper laminate according to any one of claims 1 to 9, wherein the resin layer is the outermost layer.
The paper laminate according to any one of claims 1 to 10, wherein the paper base material is the outermost layer.
The paper laminate according to any one of claims 1 to 11, wherein the thickness of the resin layer is 3 to 7 μm.
The paper laminate according to any one of claims 1 to 12, wherein the thermoplastic resin is at least one selected from an olefin / unsaturated carboxylic acid-based copolymer and polylactic acid.
A resin solution or a resin dispersion is applied to a vapor-deposited paper having a vapor-deposited layer made of a metal or ceramic having a thickness of 1 to 1000 nm on at least one surface of a paper base material, dried, and thermoplastic with a thickness of 1 μm or more and less than 15 μm. A method for producing a paper laminate, which comprises a step of forming a resin layer made of a resin.