WO2014024913A1

WO2014024913A1 - Multilayered paper container

Info

Publication number: WO2014024913A1
Application number: PCT/JP2013/071344
Authority: WO
Inventors: 奥出　秀樹
Original assignee: 日本製紙株式会社
Priority date: 2012-08-10
Filing date: 2013-08-07
Publication date: 2014-02-13
Also published as: CN104334459B; CN104334459A; KR20150042745A; HK1203915A1; JPWO2014024913A1

Abstract

The purpose of the present invention is to produce a paper container using a multilayered paper laminate material, wherein it is possible to reduce the number of production steps. A multilayered paper container at least provided with a thermoplastic resin layer (layer A), a paper base material layer (layer B), a thermoplastic resin layer (layer E), a barrier layer (layer C), an adhesive layer (layer F), and a thermoplastic resin layer (layer D) from the outer surface side towards the inner surface side, wherein the main component of layer A is a low-density polyethylene resin (LDPE), the main component of layer F is an ethylene-(meth)acrylic acid copolymer resin (E(M)AA), the main component of layer D is a linear low-density polyethylene resin (L-LDPE), and the main component of layer E is a linear low-density polyethylene resin (L-LDPE) or a low-density polyethylene resin (LDPE).

Description

Multi-layered paper container

The present invention relates to a multi-layer paper container with high storage stability. In particular, it relates to a container that can be heated and sealed.

A metal can, a glass bottle, a plastic container, a paper container, or a film or metal foil is laminated and laminated as a container for filling and packaging food and drink, pharmaceuticals, cosmetics, detergents, chemicals, miscellaneous goods, and various other contents. The container etc. which heat-sealed the laminated body and made it the bag shape are used.
In addition, in order to store the contents for a long time at room temperature, the contents are conventionally packed in an airtight container such as a metal can, a glass bottle, a plastic pouch, a laminated pouch of plastic and aluminum foil, high temperature of 120 ° C., 4 minutes or more Sterilization under high pressure (hereinafter referred to as "retort") is performed. Since retort containers are usually subjected to harsh conditions physically and chemically, the packaging materials constituting the retort containers are required to have severe packaging suitability, and their appearance, deformation resistance, Pinhole resistance, heat resistance, sealability, quality maintenance, workability, hygiene, and various other conditions are required.
On the other hand, heating conditions of food and drink are various depending on types of food and drink and sterilization conditions. For example, in Japan, the pasteurization condition of milk is defined as "a method of heating at 63 ° C for 30 minutes or having a bactericidal effect equal to or higher than this" under "Ministerial Ordinance on Component Specifications of Milk and Dairy Products". As a method equivalent to heating at 63 ° C. for 30 minutes, mention may be made of 72 to 78 ° C. for 15 seconds and 120 to 135 ° C. for 1 to 3 seconds. Furthermore, in Japan, the sterilization conditions for “packing tofu (in which soy milk is added with a coagulant and filled in containers and packaging and then heated and solidified) according to“ standards for food, additives, etc. ”are“ 90 The method is defined as “method of heating at 40 ° C for 40 minutes or method having the same or higher efficacy”, but soymilk is coagulated after filling, and as a method having the same or higher efficacy after coagulation, high temperature treatment with milk (120 ~ Similarly to the case of 135 ° C., high temperature treatment is not desirable because the product is exposed to high temperature of 100 ° C. or more, air bubbles are generated inside the tofu, and the quality and flavor are deteriorated. Moreover, the total amount of energy received by the container (accumulated amount) is higher for sterilization at low temperature for a long time than for high temperature short time sterilization, and it can be said that sterilization for low temperature long time sterilization is more severe than high temperature short time sterilization as heating conditions.
In addition, due to environmental problems, disposal of used containers and recyclability are required, and packaging simplification, weight reduction, weight reduction, and flammable properties of packaging materials are being promoted. Since the paper container can be expanded and folded, the container is not bulky, light in weight, and easily combustible, so it is excellent in ease of disposal and recyclability. For this reason, paper-based packaging materials are in widespread use.
As a paper container which preserve | saves liquid content, such as milk, the packaging material which laminated | stacked the low density polyethylene resin layer on both sides of the paper base material, and gave water resistance to paper is used. The side edges of the packaging material are stacked and heat sealed to produce various forms of packaging containers. Then, the contents are filled and packaged from the opening of the packaging container to manufacture various packaging products.
As a packaging container for long-term preservation of contents requiring barriers such as soy sauce, sake, juice, and prepared foods, a laminate obtained by laminating aluminum foil, plastic, etc. as a barrier layer on the middle layer is laminated. The used paper container is widely used.

In Patent Document 1 (Japanese Patent Application Laid-Open No. 5-213337), a multi-layered paper container in which the layer forming the inner surface of the container is a polyethylene film having an uneven surface and the layer forming the outer surface is an extrusion laminated polyethylene layer There is disclosed a multilayer paper container which is free from the problem of odor, has good heat sealability, has good surface slipperiness, and has excellent mechanical suitability at the time of molding and handling.
In Patent Document 2 (Japanese Patent Application Laid-Open No. 7-40975), the left and right end portions of a blank plate having a predetermined shape are heat-sealed to form a cylinder having a fusion-bonded portion, and one open end of the cylinder is sealed. In the case where the bottom portion is formed and the other open end of the cylindrical body is sealed to form the mouth portion, the blank plate has a base layer and an outer surface made of a polyolefin resin provided on one side of the base layer. A container comprising a laminated sheet comprising a layer and an inner surface layer made of polyacrylonitrile resin provided on the other surface of the base material layer, which has odor retention and chemical resistance to contents There is also disclosed a container which can stably store even liquid having high permeability such as alcoholic beverages.

Patent Document 3 (Japanese Patent No. 4936346) includes constituent layers of an outermost thermoplastic material layer, a paper base layer, a barrier layer, and an innermost thermoplastic material layer, and these layers are laminated in the above order. A packaging material for a liquid food paper container, wherein the innermost thermoplastic material layer is laminated by an extrusion lamination method, and linear low density polyethylene 55 having a narrow molecular weight distribution obtained by polymerization with a metallocene catalyst Consisting of a blend polymer of ̃75 wt% and 45-25 wt% of low density polyethylene obtained by polymerization with multi-site catalyst, average density of 0.905 ̃0.915, peak melting point of 88 ̃103 ° C., 15 A packaging material for a liquid food paper container, having a melt flow index of ̃17, a swelling ratio (SR) of 1.4 ̃1.6 and a layer thickness of 20 ̃30 μm Easy to pack, can be heat-sealed quickly, enables tougher seal strength, and can achieve good seal without being affected by the temperature of the filling contents, odor retention or quality retention A paper packaging container is disclosed.
The multilayer paper laminate used for this paper packaging container is produced separately from the inner layer portion on the innermost thermoplastic material layer side from the aluminum foil and the outer layer portion including the paper base and the outermost layer, and then the inner layer portion and the outer layer portion Join and manufacture.
The inner layer is a metallocene-polymerized narrow molecular weight linear low density polyethylene (mLLDPE) and high-pressure low density polyethylene blended on one side of a 9 μm thick aluminum foil to give an average density of 0.910, Melt-extrusion of an adhesive layer with a peak melting point of 97 ° C, a melt flow index of 15, a swelling ratio of 1.5 and a layer thickness of 13 μm, and a metallocene-polymerized narrow molecular weight distribution linear low density polyethylene (mLLDPE) Of high density and low density polyethylene by high pressure method, the innermost thermoplastic material layer of average density of 0.907, peak melting point of 96 ° C, melt flow index of 14, swell ratio of 1.5 and layer thickness of 25μm To form a laminated film consisting of an aluminum foil / adhesive layer / innermost thermoplastic material blend layer
The outer layer part is an extrusion temperature of 330 ° C. on a paper substrate (basis weight = 320 g / m ² ) with a thickness of 20 μm and low density polyethylene (density = 0.920 g / cm ³ , MI = 5.1) by high pressure method. The extrusion coating is applied to laminate the outermost thermoplastic material layer.
Then, the low density polyethylene / paper base paper side and the aluminum foil side of the aluminum foil laminate are blended with a metallocene catalyst polymerized linear low density polyethylene (mLLDPE) of narrow molecular weight distribution and low density polyethylene by high pressure method Then melt extrude the adhesive thermoplastic material layer with an average density of 0.920, a peak melting point of 99 ° C., a melt flow index of 17, a swelling ratio of 1.5 and a layer thickness of 12 μm, laminate and laminate A continuous long laminated packaging material is obtained.
Using this packaging material, a brick-shaped liquid food filled package is obtained in a filling machine.

Patent Document 4 (Japanese Patent Laid-Open No. 2004-17984) discloses an outermost layer made of a thermoplastic resin, a paper base layer, an intervening resin layer, a barrier layer, a pinhole resistant layer made of a thermoplastic resin, and a thermoplastic resin. A printed layer is provided on the inner surface of the outermost layer or on the surface of the paper substrate layer, there is no delamination, and the appearance and the interlayer strength are excellent. In addition, retort paper containers have been proposed which can withstand shock due to transportation.

JP-A-5-213337 Japanese Patent Laid-Open No. 7-40975 Patent 4936346 gazette JP 2004-17984 A

In containers using a multilayer paper laminate having a barrier layer such as aluminum foil, a plurality of types of thermoplastic synthetic resins are used as the outer layer, the inner layer, and the adhesive layer, and extrusion lamination is performed multiple times It was necessary, and the number of processes increased and it was complicated.
An object of the present invention is to realize a paper container using a multi-layered paper laminated material which can simplify the number of manufacturing processes. Furthermore, the present invention aims to develop a paper container suitable for low temperature and long time sterilization treatment.

The present invention is a container suitable for low-temperature long-term sterilization and using a thermoplastic synthetic resin having a common melting temperature to provide a multilayer paper container having a simple structure in which the manufacturing process is simplified. The main configurations of the present invention are as follows.

1. From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A multilayer paper container provided with a thermoplastic resin layer (D layer),
A layer is low density polyethylene resin (LDPE), F layer is ethylene / (meth) acrylic acid copolymer resin (E (M) AA), D layer and E layer are linear low density polyethylene resin (L- A multilayer paper container characterized in that it is a layer having LDPE as a main component.
2. The low density polyethylene resin (LDPE) used for the layer A has an average density of 0.910 to 0.930 g / cm ³ , a peak melting point of 105 to 125 ° C.,
The linear low density polyethylene resin (L-LDPE) used for the D layer has an average density of 0.905 to 0.935 g / cm ³ , a peak melting point of 100 to 125 ° C., and a linear chain used for the E layer Low density polyethylene resin (L-LDPE) has an average density of 0.905 to 0.935 g / cm ³ , a peak melting point of 105 to 125 ° C., and a resin used for D layer and E layer is 2.0 to It is characterized by having a melt flow rate (MFR) of 16.0 g / 10 min. Multilayer paper container as described.
3. The A layer, the E layer, the F layer, and the D layer are laminated with the B layer and the C layer by the extrusion lamination method. Or 2. Multilayer paper container as described.
4. It is a brick-like container 1. To 3. A multilayer paper container according to any of the above.
5. After filling the food and drink in a container, it is characterized in that it is heat-treated at a low temperature of 90 to 95 ° C. for a long time. To 4. A multilayer paper container according to any of the above.
6. Food and drink are characterized by tofu. Multilayer paper container as described.
7. From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A method for producing a multi-layered paper container base paper provided with a thermoplastic resin layer (D layer),
As a first step, a layer (E layer) containing a linear low density polyethylene resin (L-LDPE) as a main component is melted and extruded to a paper base layer (B layer) and a barrier layer (C layer) is formed. Supply and laminate,
As a second step, a layer (F layer) containing ethylene / (meth) acrylic acid copolymer resin (E (M) AA) as a main component on the barrier layer (C layer) side of the laminate obtained in the first step And melt extruding a layer (D layer) mainly composed of a linear low density polyethylene resin (L-LDPE) and laminating an adhesive layer (F layer) and a thermoplastic resin layer (D layer),
As the third step, the layer (A layer) mainly composed of low density polyethylene resin (LDPE) is melt extruded and laminated on the paper base layer (B layer) side of the laminate obtained in the second step.
A method of producing a base paper for a multilayer paper container, which comprises continuously laminating the above three steps.
8. From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A multilayer paper container provided with a thermoplastic resin layer (D layer),
A layer and E layer are low density polyethylene resin (LDPE), F layer is ethylene / (meth) acrylic acid copolymer resin (E (M) AA), D layer is linear low density polyethylene resin (L- A multilayer paper container characterized in that it is a layer containing LDPE as a main component.
9. The low density polyethylene resin (LDPE) used in layers A and E has an average density of 0.910 to 0.930 g / cm ³ and a peak melting point of 105 to 125 ° C.
The linear low density polyethylene resin (L-LDPE) used for the D layer has an average density of 0.905 to 0.935 g / cm ³ , a peak melting point of 100 to 125 ° C., and the linear chain used for the D layer Low density polyethylene resin (L-LDPE) and low density polyethylene resin (LDPE) used for the E layer are characterized by a melt flow rate (MFR) of 2.0 to 16.0 g / 10 min. Multilayer paper container as described.
10. From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A method for producing a multi-layered paper container base paper provided with a thermoplastic resin layer (D layer),
As the first step, the layer (E layer) mainly composed of low density polyethylene resin (LDPE) is melt extruded to the paper base layer (B layer) and the barrier layer (C layer) is supplied to perform lamination. ,
As a second step, a layer (F layer) containing ethylene / (meth) acrylic acid copolymer resin (E (M) AA) as a main component on the barrier layer (C layer) side of the laminate obtained in the first step And melt extruding a layer (D layer) mainly composed of a linear low density polyethylene resin (L-LDPE) and laminating an adhesive layer (F layer) and a thermoplastic resin layer (D layer),
As the third step, the layer (A layer) mainly composed of low density polyethylene resin (LDPE) is melt extruded and laminated on the paper base layer (B layer) side of the laminate obtained in the second step.
A method of producing a base paper for a multilayer paper container, which comprises continuously laminating the above three steps.

1. Mainly a linear low density polyethylene resin (L-LDPE) through the adhesive layer (F layer) consisting of ethylene / (meth) acrylic acid copolymer resin (E (M) AA) from the barrier layer to the inner surface side of the container By forming a layer (D layer) as a component, a container capable of maintaining strong adhesive strength and pinhole resistance even with a simple configuration is realized. Linear low density polyethylene resin is more flexible than low density polyethylene resin (LDPE), and can maintain pinhole resistance against irritation such as boiling. According to the layer configuration of the present invention, it is possible to provide a container for food and drink that requires low temperature and long time sterilization treatment.
2. The peak temperature of the resin used for layer A and E was set to 105 to 125 ° C, and the peak melting point of the resin used for layer D was set to 100 to 125 ° C, so it is suitable for paper containers heated at around 90 ° C. ing.
Since the pinhole resistance is strong, it is suitable for food and drink having various pH, and it is particularly suitable as a container for tofu filling in which the low temperature heating time is long and the accumulated heat amount is large.
3. A resin having common temperature physical properties (in particular, melt flow rate (MFR)) is used for the thermoplastic resin layer used for at least the paper base (B layer) to the resin layer (D layer) inside the container. Thus, extrusion lamination can be performed continuously. In addition, since the A layer on the surface sandwiches the B layer having high heat insulating property, the commonality is not as severe as other thermoplastic resin layers.
4. Suitable for brick-like containers, suitable for aseptic filling type paper containers.
The linear low density polyethylene resin used for the D layer has an average density of 0.905 to 0.935 g / cm ³ , the peak melting point of 100 to 125 ° C., and the resin used for the E layer has a density of 0.905 to Extrusion with an average density of 0.935 g / cm ³ , a peak melting point of 105 to 125 ° C., and a resin used for layer D and layer E having a melt flow rate of 2.0 to 16.0 / 10 minutes It is easy to carry out lamination continuously. In addition, when the resin used for the D layer and the F layer has a melt flow rate of 2.0 to 16.0 / 10 minutes, the interlayer seal between the D layer and the F layer and the lateral seal between the D layers are firmly adhered. Be done.

The figure which shows the example of the paper container of this invention. The figure which shows the structural example of the paper laminated body used for the multilayer paper container of a 1st form. The figure which shows the structural example of the paper laminated body used for the multilayer paper container of 2nd form. The figure which shows the pinhole test by an electricity supply system.

11: brick type container 12: side surface 13: front surface 14: rear surface 15: upper surface 16: lower surface 17: folding edge portion 18, 19: heat sealing portion

From the outer surface side to the inner surface side, the entire layer configuration of the multilayer paper container of the first embodiment of the present invention is at least a thermoplastic resin layer (A layer), a paper base layer (B layer), a thermoplastic resin layer E)), a barrier layer (C layer), an adhesive layer (F layer), and a thermoplastic resin layer (D layer), wherein the A layer is a low density polyethylene resin, the F layer is ethylene, The (meth) acrylic acid copolymer resin and the D layer and the E layer each have a linear low density polyethylene resin as a main component. The use of a thermoplastic resin suitable for extrusion lamination in each layer simplifies the manufacturing process. By forming a layer (D layer) mainly composed of a linear low density polyethylene resin through an adhesive layer (F layer) made of ethylene / (meth) acrylic acid copolymer resin from the barrier layer to the inner surface side of the container , Excellent in pinhole resistance.
The low density polyethylene resin used in the A layer has an average density of 0.910 to 0.930 g / cm ³ , the peak melting point of 105 to 125 ° C., and the linear low density polyethylene resin used in the D layer is 0.905 to Average density of 0.935 g / cm ³ , peak melting point of 100 to 125 ° C., linear low density polyethylene resin used for E layer, average density of 0.905 to 0.935 g / cm ³ , 105 to 125 ° C. The temperature physical properties were made common, assuming that the peak melting point, and the resin used for the D layer and the E layer had a melt flow rate of 2.0 to 16.0 / 10 minutes.
The peak melting point temperatures of the layers A and E were set to 105 to 125 ° C., and the peak melting point temperature of the layer D to 100 to 125 ° C. so as to sufficiently withstand 95 ° C. so as to correspond to the boiling.

The entire layer configuration of the multilayer paper container of the second embodiment of the present invention is at least a thermoplastic resin layer (A layer), a paper base layer (B layer), a thermoplastic resin layer (from the outer surface side to the inner surface side) E layer), a barrier layer (C layer), an adhesive layer (F layer), and a thermoplastic resin layer (D layer), wherein the A layer and the E layer are low density polyethylene resin, F layer The ethylene / (meth) acrylic acid copolymer resin and the D layer mainly contain a linear low density polyethylene resin. The use of a thermoplastic resin suitable for extrusion lamination in each layer simplifies the manufacturing process. By forming a layer (D layer) mainly composed of a linear low density polyethylene resin through an adhesive layer (F layer) made of ethylene / (meth) acrylic acid copolymer resin from the barrier layer to the inner surface side of the container , It is a paper container excellent in pinhole resistance.
The low density polyethylene resin used for layer A and layer E has an average density of 0.910 to 0.930 g / cm ³ , a peak melting point of 105 to 125 ° C., and the linear low density polyethylene resin used for layer D is 0 With an average density of 905 to 0.935 g / cm ³ , a peak melting point of 100 to 125 ° C., and a resin used for layer D and layer E having a melt flow rate of 2.0 to 16.0 / 10 minutes, The temperature property was made common.
The peak melting point temperatures of the layers A and E were set to 105 to 125 ° C., and the peak melting point temperature of the layer D to 100 to 125 ° C. so as to sufficiently withstand 95 ° C. so as to correspond to the boiling.

In the first and second embodiments of the present invention, as the main component means containing more than 50 wt%. The content is more preferably 70 wt% or more, still more preferably 80 wt% or more, and most preferably 90 wt% or more.
In the first form and the second form of the present invention, the peak melting point of the resin used in each layer is measured by differential scanning calorimetry, and at least 1 when multiple peaks are measured. The peak of the book may be included in the above temperature range.

The paper container of the present invention is suitable as a container for aseptically filling food and drink after cooking at high temperature, and as a container for food and drink after boil and readjustment, for example, at 90 ° C. to 95 ° C. after aseptic filling. For example, after tofu is mixed with soy milk and mixed with a coagulant, it is boiled at about 90 ° C. for coagulation. Then, heat treatment at a temperature of 90 ° C. for 40 minutes or a method having the same or higher efficacy is required. In addition, it is suitable for food and drink such as jelly, which is liquid at the time of filling but becomes gel after filling, in particular, contents requiring waterproofness, moisture resistance, light shielding property, oxygen barrier property and the like. It is not suitable for food and drink processed at high temperature of 100 ° C or more after filling.
The paper container of the present invention has barrier properties and heat sealing properties, can be disposed of as paper, and is excellent in volume reduction and weight reduction. When made into a brick-like container, it is excellent also in storability, preservability, and conveyance nature.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As an example of the container of the present invention, a so-called brick-type paper container will be described as an example.
The brick type paper container 11 shown in FIG. 1 is a container formed by bending a base paper for paper container and heat-sealing (heat sealing) side surfaces and upper and lower openings to form a square brick-like cube. The right and left sides 12, the front surface 13, the back surface 14, the upper surface 15, and the lower surface 16 are constituted by six surfaces. The side portions of the base paper for paper containers are heat-sealed portions 18 which are overlapped and joined. Further, the upper and lower end portions are also overlapped and joined to form a thermally fused portion 19. The folded-ear portion 17 is joined to the side surface 12 by being bent from the upper surface portion to the side surface portion. The heat sealing portion 18 is bent from the back surface to the upper surface or the lower surface in a state of being overlapped at the bending corner portion. Further, the heat-sealing part 19 is bent in a state of being overlapped at the bending corner part from the upper surface to the side surface.
The shape itself of the brick-like paper container is similar to that of the conventional one.

The structural example of the paper laminated body used for the multilayer paper container of a 1st form is shown in FIG.
The layer structure of the paper laminate is at least a thermoplastic resin layer (A layer), a paper base layer (B layer), a thermoplastic resin layer (E layer), a barrier layer (C layer) from the outer surface side to the inner surface side ), An adhesive layer (F layer), and a thermoplastic resin layer (D layer).
The printed layer uses a pre-printed paper substrate. It is also possible not to provide this printing layer. Moreover, a printing layer can also be provided on the surface of A layer. An adhesive layer (G layer) made of a thermoplastic resin may be provided between the thermoplastic resin layer (E layer) and the barrier layer (C layer).
A layer is low density polyethylene resin (LDPE), F layer is ethylene / (meth) acrylic acid copolymer resin (E (M) AA), D layer and E layer are linear low density polyethylene resin (L- Each of LDPE) is a main component.

The low density polyethylene resin (LDPE) used for the layer A has an average density of 0.910 to 0.930 g / cm ³ and a peak melting point of 105 to 125 ° C.

The paper base used for the layer B can be appropriately selected according to the desired quality of the paper container, and is not particularly limited. For example, the paper base used for a paper container for liquid packaging can be used . A single layer paper base or a multilayer paper base can be used. It is preferable to be excellent in bending resistance and drop impact absorption, molding water resistance, and the like.
For example, a multilayer paper base in which a high density layer is formed on both sides of a low density inner layer is a paper base excellent in the function of the low density layer to absorb bending stress and impact from falling.
The paper base contains, as an internal sizing agent, at least 0.15 parts by weight but less than 0.80 parts by weight based on 100 parts by weight of total raw material pulp (absolute dry pulp weight) to improve water resistance. It is also effective to do. Furthermore, the addition of a cationized starch, an amphoteric starch, a starch such as oxidized starch, and / or a sulfuric acid band is preferable because it has the effect of improving the fixing of the alkyl ketene dimer to the pulp and in particular improves the water resistance.

The barrier material used for C layer can use barrier materials, such as aluminum foil generally used for a multilayer paper container.
A common aluminum metal can be used as aluminum which comprises a thin film layer of aluminum foil or aluminum.

The linear low density polyethylene resin (L-LDPE) used for the D layer has an average density of 0.905 to 0.935 g / cm ³ and a peak melting point of 100 to 125 ° C. Low density polyethylene resin (L-LDPE) has an average density of 0.905 to 0.935 g / cm ³ and a peak melting point of 105 to 125 ° C., and is a linear low density polyethylene used for D layer and E layer The resin (L-LDPE) is preferably a melt flow rate (MFR) of 2.0 to 16.0 / 10 minutes. By setting the average density, the peak melting point, and the melt flow rate (MFR) in the above-mentioned ranges, it is preferable to perform extrusion lamination continuously, which is preferable. More preferably, the average density of the linear low density polyethylene resin (L-LDPE) used in the D layer is 0.905 to 0.935 g / cm ³ , the peak melting point is 105 to 125 ° C., and more preferably the D layer And E layers, the average density of linear low density polyethylene resin (L-LDPE) is 0.910 to 0.925 g / cm ³ , the peak melting point is 105 to 125 ° C., and the melt flow rate (MFR) is 6. 0 to 15.0 / 10 minutes, and most preferably, the average density of linear low density polyethylene resin (L-LDPE) used in layer D and layer E is 0.910 to 0.925 g / cm ³ , The peak melting point is 105 to 125 ° C., and the melt flow rate (MFR) is 8.0 to 12.0 / 10 minutes.
In the present invention, the edges of the base paper for paper containers are heat-sealed (heat-sealed) in order to constitute the paper container, but the transverse seal formed by the heat seal required at that time is firmly adhered. In this multilayer paper container, the two edge D / D layers are heat sealed to form a transverse seal, but the transverse seal exhibits sufficient resistance even when heated at a low temperature for a long time.

The ethylene / (meth) acrylic acid copolymer resin (E (M) AA) used for the F layer is not particularly limited, which is determined according to the required performance, but usually, the average density is 0.910 to 0 .950 g / cm ³ , peak melting point 80 to 110 ° C., melt flow rate (MFR) 2.0 to 16.0 / 10 minutes, D layer and ethylene (meth) acrylic acid copolymer resin The adhesive property with the adhesive layer (F layer) consisting of (E (M) AA), that is, the adhesive strength between the D layer and the F layer is good and also the pinhole resistance against stimuli such as boiling and the side of the paper container It is preferable because the adhesiveness of the sealing portion (the portion of No. 19 in FIG. 1: the bonding portion between the thermoplastic resin layers (D layers) on the inner surface of the container) becomes good.

The thermoplastic resin used for the G layer is not particularly limited, but the resin used for the F layer is preferably used.

The structural example of the paper laminated body used for the multilayer paper container of 2nd form is shown in FIG.
The layer structure of the paper laminate is at least a thermoplastic resin layer (A layer), a paper base layer (B layer), a thermoplastic resin layer (E layer), a barrier layer (C layer) from the outer surface side to the inner surface side ), An adhesive layer (F layer), and a thermoplastic resin layer (D layer).
The printed layer uses a pre-printed paper substrate. It is also possible not to provide this printing layer. Moreover, a printing layer can also be provided on the surface of A layer. An adhesive layer (G layer) made of a thermoplastic resin may be provided between the thermoplastic resin layer (E layer) and the barrier layer (C layer).
A layer and E layer are low density polyethylene resin (LDPE), F layer is ethylene / (meth) acrylic acid copolymer resin (E (M) AA), D layer is linear low density polyethylene resin (L- LDPE) is a layer containing each as a main component.

The low density polyethylene resin (LDPE) used for the E layer has an average density of 0.910 to 0.930 g / cm ³ and a peak melting point of 105 to 125 ° C.
As the A layer, B layer, C layer, D layer, F layer, and G layer, those used for the first paper laminate can be used.

Linear low density polyethylene resin (L-LDPE) used in layer D and low density polyethylene resin (LDPE) used in layer E have a melt flow rate (MFR) of 2.0 to 16.0 / 10 minutes Is preferred. By setting the average density, the peak melting point, and the melt flow rate (MFR) in the above-mentioned ranges, it is preferable to perform extrusion lamination continuously, which is preferable. More preferably, the average density of the linear low density polyethylene resin (L-LDPE) used in the D layer is 0.905 to 0.935 g / cm ³ , the peak melting point is 105 to 125 ° C., and more preferably D The average density of the linear low density polyethylene resin (L-LDPE) used in the layer and the low density polyethylene resin (LDPE) used in the E layer is 0.910 to 0.925 g / cm ³ , and the peak melting point is 105 to 125 ° C, melt flow rate (MFR) 6.0 to 15.0 / 10 min, most preferably linear low density polyethylene resin (L-LDPE) used in layer D and low used in layer E Density polyethylene resin (LDPE), the average density is 0.910 to 0.925 g / cm ³ , the peak melting point is 105 to 125 ° C., and the melt flow rate (MFR) is 8. It is 0 to 12.0 / 10 minutes.

In the present invention, the edges of the base paper for paper containers are heat-sealed (heat-sealed) in order to constitute the paper container, but the transverse seal formed by the heat seal required at that time is firmly adhered. In this multilayer paper container, the two edge D / D layers are heat sealed to form a transverse seal, but the transverse seal exhibits sufficient resistance even when heated at a low temperature for a long time.
Example 1

<Layer composition>
Thermoplastic resin (layer A):
LDPE (manufactured by Japan Polyethylene Corporation, product name: LC602A,
Average density 0.919 g / cm ³ , peak melting point 107 ° C., MFR 8.2)
Paper base layer (B layer): base paper for liquid packaging having a basis weight of 200 g / m ² (one-layer structure)
Thermoplastic resin (E layer):
L-LDPE (manufactured by Japan Polyethylene Corporation, product name: NH745N,
Average density 0.913 g / cm ³ , peak melting point 121 ° C., MFR 8.0)
-Barrier layer (C layer): Aluminum foil (Sumitomo Light Metal Co., Ltd., 7 μm thick)
Adhesive layer (F layer):
EMAA (made by Mitsui DuPont, product name: NC0908C,
Average density 0.930 g / cm ³ , peak melting point 99 ° C., MFR 8.0)
Thermoplastic resin (D layer):
L-LDPE (manufactured by Japan Polyethylene Corporation, product name: NH745N,
Average density 0.913 g / cm ³ , peak melting point 121 ° C., MFR 8.0)

<Process>
By sequentially laminating the following three steps, a base paper 1 for multilayer paper container is produced.
First step:
The L-LDPE layer (E layer) is melt-extruded to the paper base layer (B layer) and the barrier layer (C layer) is supplied for lamination,
Second step:
Adhesive layer (F layer) and thermoplastic resin by melt-extrusion of the EMAA layer (F layer) and L-LDPE layer (D layer) on the barrier layer (C layer) side of the laminate obtained in the first step Layer (D layer),
Third step:
The LDPE layer (A layer) is melt extruded and laminated on the paper base layer (B layer) side of the laminate obtained in the second step.

<Preparation of paper container>
About the obtained base paper for multilayer paper containers, using a filling machine (machine name / model number: UP-FUJI MA60, manufactured by Shikoku Kako Co., Ltd., SLIM 200 ml setting), a brick type paper container (filling material: water shown in FIG. 1) ) Were continuously produced.
Example 2

The adhesive layer (F layer) is an ethylene / acrylic acid copolymer resin (EAA) (Made by Dow Chemical Company, product name: PRIMACOR 3003) having an average density of 0.935 g / cm ³ , peak melting point 100 ° C. and MFR 7.8. In the same manner as in Example 1, a multi-layer paper container base paper 2 and a paper container were produced.
[Example 3]

Base paper 3 for a multilayer paper container and a paper container in the same manner as in Example 2 except that the LDPE layer (layer A) was added with an EAA resin (PRIMACOR 3003) to be 5 wt% and made a layer containing LDPE as a main component. Was produced.
Example 4

Base paper for multi-layered paper containers in the same manner as in Example 3 except that L-LDPE was added to L-LDPE layer (D layer) so that 10 wt% of LDPE resin (LC602A) was added to make L-LDPE-based layer. 4 and a paper container were made.
[Examples 5 to 7]

The same as Example 4 except that L-LDPE was used as the main layer by adding LDPE resin (LC602A) to L-LDPE layer (D layer) to be 15 wt%, 25 wt% and 45 wt%, respectively. Then, base papers 5 to 7 for multilayer paper containers and paper containers were produced.
[Example 8]

A base paper for a multilayer paper container 8 in the same manner as in Example 4 except that the L-LDPE layer (E layer) was added with an EAA resin (PRIMACOR 3003) in an amount of 5 wt% to make the layer mainly composed of L-LDPE. And made a paper container.
[Example 9]

For a multilayer paper container in the same manner as in Example 3 except that the L-LDPE layer (E layer) is a layer mainly composed of LDPE consisting of 95 wt% of LDPE resin (LC602A) and 5 wt% of EAA resin (PRIMACOR 3003) The base paper 9 and a paper container were produced.
[Examples 10 to 13]

A multilayer was prepared in the same manner as in Examples 4 to 7 except that the L-LDPE layer (E layer) was a layer containing LDPE as a main component consisting of 95 wt% of LDPE resin (LC602A) and 5 wt% of EAA resin (PRIMACOR 3003). Base papers 10 to 13 for paper containers and paper containers were produced.
Example 14

Example 10 is the same as Example 10 except that an adhesive layer (G layer) made of an EAA resin (PRIMACOR 3003) is provided between the layer (E layer) containing LDPE as the main component and the barrier layer (C layer) according to the following steps. A multi-layered paper container base paper 14 and a paper container were produced.

<Process>
By sequentially laminating the following three steps, a base paper 14 for multilayer paper container is produced.
First step:
(E layer) and adhesive layer (G layer) mainly composed of LDPE are melt extruded to a paper base layer (B layer) and a barrier layer (C layer) is supplied for lamination,
Second step:
Adhesive layer (F layer) by melt-extruding the EAA layer (F layer) and the layer containing L-LDPE as the main component (D layer) on the barrier layer (C layer) side of the laminate obtained in the first step ) And thermoplastic resin layer (D layer),
Third step:
A layer (layer A) containing LDPE as a main component is melt extruded and laminated on the paper base layer (layer B) side of the laminate obtained in the second step.
[Example 15]

The layer (D layer) containing L-LDPE as a main component has an average density of 0.910 g / cm ³ , a peak melting point of 124 ° C., and an MFR of 15 with L-LDPE (Dow Chemical Company, product name: ELITE 5815) In the same manner as in Example 14, a base paper 15 for multilayer paper containers and a paper container were produced.
[Example 16]

A multilayer paper was prepared in the same manner as in Example 14 except that in the layer (D layer) containing L-LDPE as the main component, L-LDPE having an average density of 0.913 g / cm ³ , peak melting point of 121 ° C. and MFR 6.0 was used. Container base paper 16 and a paper container were produced.
[Example 17]

Base paper 17 for multilayer paper containers and multilayer paper container in the same manner as in Example 13 except that the layer containing LDPE as the main component (E layer) is a layer consisting of 60 wt% of LDPE (LC602A) and 40 wt% of L-LDPE (NH745N). A paper container was made.
[Example 18]

Example except that in the layer (A layer) containing LDPE as the main component, LDPE (product name: KC507S, manufactured by Japan Polyethylene Corporation) having an average density of 0.906 g / cm ³ , a peak melting point of 102 ° C., and an MFR of 10.5. The same procedure as No. 14 was carried out to prepare a multilayer paper container base paper 18 and a paper container.
[Example 19]

An example except that in the layer (E layer) containing LDPE as a main component, the average density is 0.906 g / cm ³ , peak melting point is 102 ° C., and MFR is 10.5 LDPE (product name: KC507S, manufactured by Japan Polyethylene Corporation). In the same manner as in 14, a base paper 19 for multilayer paper containers and a paper container were produced.
[Example 20]

The thermoplastic resin (D layer) is L-LDPE having an average density of 0.921 g / cm ³ , a peak melting point of 122 ° C., and an MFR of 12.0, and as the second step, the barrier layer (C of the laminate obtained in the first step) Example 1 except that the EMAA layer (F layer) and the L-LDPE layer (D layer) were melt-extruded on the layer side and the adhesive layer (F layer) and the thermoplastic resin layer (D layer) were laminated, respectively. In the same manner as in the above, a base paper 20 for multilayer paper containers and a paper container were produced.
[Example 21]

A thermoplastic resin (D layer) is L-LDPE having an average density of 0.930 g / cm ³ , a peak melting point of 123 ° C., and an MFR of 11.0, and as a second step, the barrier layer (C of the laminate obtained in the first step) Example 1 except that the EMAA layer (F layer) and the L-LDPE layer (D layer) were melt-extruded on the layer side and the adhesive layer (F layer) and the thermoplastic resin layer (D layer) were laminated, respectively. In the same manner as in the above, a base paper 21 for multilayer paper containers and a paper container were produced.
Example 22

A thermoplastic resin (D layer) is L-LDPE having an average density of 0.937 g / cm ³ , a peak melting point of 123 ° C., and an MFR of 11.0, and as a second step, the barrier layer (C of the laminate obtained in the first step) Example 1 except that the EMAA layer (F layer) and the L-LDPE layer (D layer) were melt-extruded on the layer side and the adhesive layer (F layer) and the thermoplastic resin layer (D layer) were laminated, respectively. In the same manner as in the above, a base paper 22 for multilayer paper containers and a paper container were produced.
[Example 23]

A thermoplastic resin (D layer) is L-LDPE having an average density of 0.901 g / cm ³ , a peak melting point of 112 ° C., and an MFR of 8.0, and as a second step, a barrier layer of the laminate obtained in the first step (C Example 1 except that the EMAA layer (F layer) and the L-LDPE layer (D layer) were melt-extruded on the layer side and the adhesive layer (F layer) and the thermoplastic resin layer (D layer) were laminated, respectively. In the same manner as in the above, a base paper 23 for multilayer paper containers and a paper container were produced.

Comparative Example 1

The adhesive layer (F layer) and the thermoplastic resin (D layer) were made L-LDPE having an average density of 0.930 g / cm ³ , a peak melting point of 123 ° C., and an MFR of 11.0, and were obtained in the first step as the second step. The L-LDPE layer (F layer) and the L-LDPE layer (D layer) are respectively melt-extruded on the barrier layer (C layer) side of the laminate to form an adhesive layer (F layer) and a thermoplastic resin layer (D layer) A multilayer paper container base paper 24 and a paper container were produced in the same manner as in Example 1 except that the above were laminated.

Comparative example 2

Thermoplastic resin (D layer) was used as LDPE with an average density of 0.928 g / cm ³ , peak melting point of 114 ° C., and MFR 3.0 (product name: LC561 manufactured by Japan Polyethylene Corporation), obtained as the second step in the first step Each of the EMAA layer (F layer) and the LDPE layer (D layer) is melt-extruded on the barrier layer (C layer) side of the laminated body, and the adhesive layer (F layer) and the thermoplastic resin layer (D layer) are laminated. In the same manner as in Example 1 except for the above, a base paper 25 for multilayer paper containers and a paper container were produced.

Comparative example 3

Thermoplastic resin (D layer) was made into LDPE (Made in Japan, product name: M201P) with an average density of 0.917 g / cm ³ , peak melting point of 106 ° C. and MFR 8.0, obtained as the second step in the first step Each of the EMAA layer (F layer) and the LDPE layer (D layer) is melt-extruded on the barrier layer (C layer) side of the laminated body, and the adhesive layer (F layer) and the thermoplastic resin layer (D layer) are laminated. A multilayer paper base paper 26 and a paper container were produced in the same manner as in Example 1 except for the above.

Comparative example 4

A multilayer paper base paper 27 and a paper container were produced in the same manner as in Example 3 except that 55 wt% of LDPE resin (LC602A) was added to the L-LDPE layer (E layer).

Comparative example 5

A base paper 28 for a multilayer paper container and a paper container were produced in the same manner as in Example 3 except that 75 wt% of LDPE resin (LC602A) was added to the L-LDPE layer (E layer).

The physical properties of the resin and the layer D of each layer of the base paper for multilayer paper containers prepared in Examples and Comparative Examples are shown in Tables 1 and 2.

Using the paper containers prepared in Examples and Comparative Examples, pinhole resistance test, adhesion test between C / F layers, adhesion test of transverse seal portion (D / D layers) were carried out, and I made an evaluation.

<Pinhole resistance test>
(A: container inner surface)
A paper container heated (boiled) in hot water at 90 ° C. for 40 minutes with filling material (water) cut into two in the lateral direction at the center of the body, and the inside of the container is filled with water. This is immersed in water, and it is energized at 1 kV between the inner surface and the outer surface of the container using an energizing checker (Pinhole checker HV-M, manufactured by Shinko Electric Instruments Co., Ltd.), and the presence or absence of an electrification reaction is confirmed.
A schematic diagram of a pinhole test according to the energization method is shown in FIG. As shown in FIG. 4 (a), when no pinholes are generated in the adhesive layer (F layer) and the thermoplastic resin layer (D layer) on the inner surface of the container, the barrier layer (C layer) which is a conductive layer Since the aluminum foil is electrically insulated, it is not energized. On the other hand, when a pinhole is generated, as shown in FIG. 4 (b), the inner liquid (water) → pinhole → aluminum foil → end face of aluminum foil → outside liquid via the pinhole Electricity flows in the order of (water), and energization is detected.

(B: container outer surface)
If there is an electrification reaction, the outer surface of the container is further dipped in a red penetrant (water to which a red dye is added) to confirm the presence or absence of staining of the paper substrate (B layer). When a pinhole is generated in the thermoplastic resin layer (layer A) on the outer surface of the container, the red penetrant is permeated from the pinhole and the paper substrate (layer B) is dyed.

Evaluation criteria are as follows.
Evaluation 5: In 500 paper containers (1000 measurement samples), no pinhole is generated on both the inner surface and the outer surface of the container (a pinhole is present on the inner surface of the container = no paper container having an electric reaction).
Evaluation 4: In 500 paper containers (1000 measurement samples), although pinholes are generated on the inner surface of a very small amount of container, pinholes are not generated on the outer surface of the container (pin holes are formed on the inner surface of the container) One paper container is 1
1 or more and less than 5 out of 000, and there are pinholes on the outer surface of the container = 0 paper containers on which a paper base (layer B) is dyed).
Evaluation 3: In 500 paper containers (1000 measurement samples), although a pinhole is generated on the inner surface of a small amount of containers, no pinhole is generated on the outer surface of the container (a pinhole is formed on the inner surface of the container) 10 paper containers
There are 5 or more and less than 10 in 00, and there are pinholes on the outer surface of the container = 0 paper containers on which the paper base (layer B) is dyed).
Evaluation 2: In 500 paper containers (1000 measurement samples), although a pinhole is generated on the inner surface of the container, no pinhole is generated on the outer surface of the container (a paper container having a pinhole on the inner surface of the container) There are 10 or more out of 1000, and there are pinholes on the outer surface of the container = 0 paper containers (layer B) are dyed).
Evaluation 1: In 500 paper containers (1000 measurement samples), pinholes are also generated on the outer surface of the container (there is pinhole on the outer surface of the container =
One or more paper containers on which a paper substrate (layer B) is dyed).

<Adhesion test between C layer and F layer>
The interface between the barrier layer (C layer) and the adhesive layer (F layer) was nicked with a razor, hand-hooked there and peeled off, and the adhesion between the C layer and the F layer was evaluated.
Evaluation criteria are as follows.
OK: It does not peel off at the interface of C layer and F layer.
NG: Peeling off at the interface between the C layer and the F layer.

<Adhesiveness test of horizontal seal part (D layer / D layer)>
Horizontal seal of a paper container heated (boiled) in hot water at 90 ° C for 40 minutes with the filler (water) in place (location No. 19 in Fig. 1: thermoplastic resin layer (D layer) on the inner surface of the container) A razor cut was made in the interface between the bonding parts), and the hand was pulled off and peeled off to evaluate the adhesion of the lateral sealing part.
Since the transverse seal is an essential element for forming a paper container, it is necessary to confirm that the transverse seal does not peel off.
Evaluation criteria are as follows.
Evaluation 3: It does not peel off at the horizontal seal portion (the interface between the D layer and the D layer).
Evaluation 2: Although it does not peel off at the transverse seal portion (the interface between the D layer and the D layer), the adhesive layer (F
(Layer) and the thermoplastic resin layer (layer D) peel off.
Evaluation 1: Peeling off at the transverse seal portion (the interface between the D layer and the D layer).

Table 3 shows the evaluation results of the paper containers prepared in the example and the comparative example.

In the test results in Table 3, those with Evaluation 1 or NG are judged not to be suitable as the multilayer paper container of the present invention.
Evaluations of 2 or more, and OK or more are judged as usable multilayer paper containers, and are taken as examples. In the examples, the pinhole resistance is given priority and overall evaluation results show Examples 1 to 5, 8 to 11, 14-19, 20, 21, 22 are particularly good multilayer paper containers. Furthermore, the conditions of Examples 1 to 4, 8 to 10, 14, 17 and 20 are pinhole resistance, adhesion between the inner layer side of the barrier layer (C layer) and the inner surface of the container than the aluminum foil, and lateral seal of the container. The results are excellent for both adhesion (heat sealability).
If pinholes occur on both the inside and outside of the container, the outside air intrudes into the inside of the container and leads to deterioration and decay of the food and drink that are the contents, or the contents exude to the outside of the container and cause staining and odor Lead to In addition, even if pinholes occur only on the inner surface of the container, the aluminum foil of the barrier layer (C layer) and the contents come into contact, and depending on the type of contents, the aluminum foil is corroded. May lead to the deterioration of the entire container. Thus, since pinhole resistance is an element related to the intrinsic physical properties of the container, it was an important evaluation element.
Since the adhesion test of the transverse seal portion is a heating test in water at 90 ° C. for 40 minutes, it is shown that the multilayer paper container of the present invention has a heat sealability sufficiently resistant to sterilization at low temperatures for a long time ing.
The multilayer paper container of the present invention is a combination of the adhesive layer (F layer) with E (M) AA and the thermoplastic resin layer (D layer) with L-LDPE as a main component. It has been confirmed that sufficient adhesive strength is exhibited between the layers on the inner surface side of the container rather than the aluminum foil of the layer).
By this test, a paper container configuration that can be sterilized at low temperature for a long time can be developed, and it is confirmed that extrusion lamination can be continuously performed by combination of thermoplastic resins constituting each layer to manufacture base paper for multilayer paper containers. did it.

Claims

From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A multilayer paper container provided with a thermoplastic resin layer (D layer),
A layer is low density polyethylene resin (LDPE), F layer is ethylene / (meth) acrylic acid copolymer resin (E (M) AA), D layer and E layer are linear low density polyethylene resin (L- A multilayer paper container characterized in that each of LDPE) is a main component.
The low density polyethylene resin (LDPE) used for the layer A has an average density of 0.910 to 0.930 g / cm 3 , a peak melting point of 105 to 125 ° C.,
The linear low density polyethylene resin (L-LDPE) used for the D layer has an average density of 0.905 to 0.935 g / cm 3 , a peak melting point of 100 to 125 ° C., and a linear chain used for the E layer Low density polyethylene resin (L-LDPE) has an average density of 0.905 to 0.935 g / cm 3 , peak melting point of 105 to 125 ° C., and linear low density polyethylene used for D layer and E layer The multilayer paper container according to claim 1, wherein the resin (L-LDPE) is a melt flow rate (MFR) of 2.0 to 16.0 g / 10 min.
The multilayer paper container according to claim 1 or 2, wherein the layer A, the layer E, the layer F, and the layer D are formed by an extrusion lamination method.
The multilayer paper container according to any one of claims 1 to 3, which is a brick-like container.
The multi-layered paper container according to any one of claims 1 to 4, which is heat-treated to 90 to 95 属 C after filling the container with the food and drink.
The multi-layered paper container according to claim 5, wherein the food and drink is tofu.
From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A method for producing a multi-layered paper container base paper provided with a thermoplastic resin layer (D layer),
As a first step, a layer (E layer) containing a linear low density polyethylene resin (L-LDPE) as a main component is melted and extruded to a paper base layer (B layer) and a barrier layer (C layer) is formed. Supply and laminate,
As a second step, a layer (F layer) containing ethylene / (meth) acrylic acid copolymer resin (E (M) AA) as a main component on the barrier layer (C layer) side of the laminate obtained in the first step And melt extruding a layer (D layer) mainly composed of a linear low density polyethylene resin (L-LDPE) and laminating an adhesive layer (F layer) and a thermoplastic resin layer (D layer),
As the third step, the layer (A layer) mainly composed of low density polyethylene resin (LDPE) is melt extruded and laminated on the paper base layer (B layer) side of the laminate obtained in the second step.
A method of producing a base paper for a multilayer paper container, which comprises continuously laminating the above three steps.
From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A multilayer paper container provided with a thermoplastic resin layer (D layer),
A layer and E layer are low density polyethylene resin (LDPE), F layer is ethylene / (meth) acrylic acid copolymer resin (E (M) AA), D layer is linear low density polyethylene resin (L- A multilayer paper container characterized in that each of LDPE) is a main component.
The low density polyethylene resin (LDPE) used in layers A and E has an average density of 0.910 to 0.930 g / cm 3 and a peak melting point of 105 to 125 ° C.
The linear low density polyethylene resin (L-LDPE) used for the D layer has an average density of 0.905 to 0.935 g / cm 3 , a peak melting point of 100 to 125 ° C., and the linear chain used for the D layer Low density polyethylene resin (L-LDPE) and low density polyethylene resin (LDPE) used for the E layer have a melt flow rate (MFR) of 2.0 to 16.0 g / 10 min. The multi-layered paper container according to 8.
From the outer surface side to the inner surface side, at least the thermoplastic resin layer (A layer), the paper base layer (B layer), the thermoplastic resin layer (E layer), the barrier layer (C layer), the adhesive layer (F layer) A method for producing a multi-layered paper container base paper provided with a thermoplastic resin layer (D layer),
As the first step, the layer (E layer) mainly composed of low density polyethylene resin (LDPE) is melt extruded to the paper base layer (B layer) and the barrier layer (C layer) is supplied to perform lamination. ,
As a second step, a layer (F layer) containing ethylene / (meth) acrylic acid copolymer resin (E (M) AA) as a main component on the barrier layer (C layer) side of the laminate obtained in the first step And melt extruding a layer (D layer) mainly composed of a linear low density polyethylene resin (L-LDPE) and laminating an adhesive layer (F layer) and a thermoplastic resin layer (D layer),
As the third step, the layer (A layer) mainly composed of low density polyethylene resin (LDPE) is melt extruded and laminated on the paper base layer (B layer) side of the laminate obtained in the second step.
A method of producing a base paper for a multilayer paper container, which comprises continuously laminating the above three steps.