JP2006256293A - Polyolefine film for paper container for liquid, material of paper container for liquid using it, and aseptic paper container for liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide film and material of paper containers for liquid in order to provide paper containers good in strength, which have sufficient heat-seal strength and sustainable laminate adhesion strength, and which allows to easily insert a straw without decreasing buckling strength of the paper containers. <P>SOLUTION: A polyolefine film I layer is composed of polyolefine or polyolefine composition having a specified range of melting points. An oriented polyolefine film II layer is formed by biaxial orientation of polyolefin composition having a specified range of melting points. The oriented polyolefine film II layer overlies the polyolefine film I layer for forming a biaxially oriented laminated polyolefine film for the paper containers for liquid, which has a coefficient of a surface orientation of 0.6 or lower. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a biaxially stretched laminated polyolefin film for a liquid paper container having excellent buckling strength and low piercing strength and having a straw piercing property, and a liquid paper container material and liquid paper container using the same.

Conventionally, as a liquid paper container for milk, juice or other beverages,
Various types of containers such as a flat top type and a brick type are known. Of these, the brick-type liquid paper container is mostly used to stab the straw attached to the side of the paper container and drink the contents.

Such a brick type liquid paper container is manufactured by using an aseptic filling molding machine, which is formed from a liquid paper container material in which a thermoplastic resin layer is laminated on paper and filled with contents. That is, the liquid paper container material continuous in a strip shape is sterilized with hydrogen peroxide solution continuously using, for example, an aseptic filling machine such as UP-FUJI filling machine manufactured by Shikoku Koki K. In the chamber, a longitudinal seal is applied in the longitudinal direction to form a tube, and the liquid paper container material formed into a tube is filled with the contents to be filled (contents), and predetermined in the lateral direction of the tubular liquid paper container material It can be manufactured by applying a horizontal line seal at every interval, cutting the packaging material along the horizontal line seal part, folding it along the crease, and forming the final shape.

The shape of the liquid paper container obtained by aseptic filling molding is not limited to the brick type, that is, the brick type. Since there are various shapes such as a polygonal column, and they are actually widely used, the liquid paper containers obtained by the aseptic filling molding will be collectively referred to as an aseptic type liquid paper container.
In the above aseptic type liquid paper container, the contents are mostly stabbed with a straw attached to the side of the paper container. On the other hand, as a liquid paper container material for forming this type of liquid paper container, usually, from the outer surface of the paper container, polyethylene I layer / printing layer / polyethylene II layer / paper layer / polyethylene III layer / aluminum foil layer / polyethylene IV layer, etc. In many cases, a laminated body having the structure is used (see, for example, Patent Document 1 and Patent Document 2). In this case, the straw pierce is provided by cutting out the printed layer / polyethylene II layer / paper layer portion of the laminate, and the straw is substantially made of polyethylene I layer / polyethylene III layer / aluminum foil layer / polyethylene IV. It has a form that penetrates the layered product and reaches the contents. For this reason, unstretched polyolefin films having a low piercing strength have been used for the polyethylene I, III, and IV layers in the structure of the laminate that pierces the straw.

However, the unstretched polyolefin film with low piercing strength is excellent in straw piercing property, but the film strength is small, so if the film thickness is not increased, the buckling strength of the paper container will be low and the paper container will be deformed during transportation, Alternatively, there is a problem that handling properties when paper container products are displayed at a store or carried into a vending machine are inferior. Further, in order to increase the buckling strength of the paper container, the paper weight of the paper layer may be increased to increase the paper thickness. Along with this, there arises a problem that the molding retainability after molding after folding or folding becomes insufficient, or the cost increases. In addition, in order to increase the buckling strength of the paper container, the film thickness of each layer may be increased. However, if the film thickness is increased, the straw piercing property becomes insufficient or the cost increases. Arise. Here, the buckling strength is a compressive load per unit area when the paper container is deformed when a compressive load is applied in the axial direction of the paper container.
It is used as a numerical value that represents the strength of the paper container.

If the buckling strength increases, the strength against external force increases, so that the safety and performance of the paper container can be improved. In general, it is known that a biaxially stretched polyolefin film has a large film, and it is conceivable that the biaxially stretched polyolefin film is laminated in a constituent member that pierces a straw. However, when the biaxially stretched polyolefin film is interposed in a component that is pierced with a straw, the buckling strength of the paper container can be increased, but the piercing strength is too high, so that there is a new problem that piercing with a straw cannot be performed. Arise.

On the other hand, a film having a straw piercing property has a thickness of 50 in Patent Document 3.
A lid for a polystyrene resin cup has been devised in which a biaxially stretched polyester film having a thickness of 4 μm to 9 μm is laminated on top and bottom of a paper of g / m ² to 120 g / m ² . Patent Document 4 describes a film excellent in straw piercing property obtained by biaxially stretching a polyester-based resin composition for improving the piercing property of a straw in a beverage lid or a blister backing material. However, there is no description about the construction of the entire liquid paper container using a polyester film as a constituent member, and the polyester film is expensive and practical as a base material constituting the whole container such as a paper container. Difficult to make.

Patent Document 5 devises a cover material in which uniaxially stretched or rolled film easily tearable films having unidirectionality are laminated. However, an easily tearable film having a unidirectional property has a strong molecular orientation in one direction that can be torn, and thus a strong strength in the molecular orientation direction. It will be lower. For this reason, as the material constituting the entire container such as a paper container, the buckling strength of the entire container is required, so there is a problem that the film thickness must be increased to compensate for the buckling strength in the direction of small molecular orientation. Arise.

Patent Document 6 has devised a laminated film in which several tens of thousands to several hundreds of μm of holes as micropores / m ^{2 are} provided in a thermoplastic resin film to facilitate straw piercing. However, in order to provide fine holes in the film, a new process for providing fine holes in the thermoplastic resin film is required, which increases the cost.

Based on this technical recognition, the present inventors, based on Patent Document 5, use a biaxially stretched polyolefin film having hand-cutting properties, thereby providing an inexpensive material having both targeted film strength and straw piercing property. We thought that we could not get and examined. For example, in Patent Document 7, a resin constituting the central layer is coextruded as a crystalline low molecular weight polyolefin, and a resin constituting both surface layers is coextruded as a crystalline polyolefin having a higher melting point than the resin constituting the central layer 3 A biaxially stretched polyolefin film having a hand cutting property in which a layer sheet is biaxially stretched and only the center layer is melted to be non-oriented by heat treatment is described.

However, although the above-mentioned co-pressing film has both a straw piercing property and an appropriate film strength when used alone, when used as a constituent member of a liquid paper container material, the co-pressing film has a central layer and both outer layers. Because of the difference in resin and the degree of orientation of the layers, interface separation occurs between the center layer and both outer layers. It was found that there was a problem that the strength did not increase.

In addition, when the liquid paper container material is used, it is necessary to laminate various materials and sealants on both sides of the co-pressed film. Next, it was also found that the laminate performed on the other side has a problem that the laminate adhesive strength is lowered. This is because the molecular motion of additives and low molecular weight components contained in the resin of the film is activated by the heat of the drying oven or the like during the first one-side lamination, and the other one-side film surface is in the resin. Since the additive and low molecular weight component contained bleed and cover the surface, it is considered that the laminate adhesive strength is lowered.

JP-A-11-216814 JP-A-11-216821 Japanese Utility Model Publication No. 7-028866 JP 2003-213108 A JP-A-9-323377 JP-A-8-147552 JP 58-25930 A

Therefore, using an inexpensive biaxially oriented polyolefin film, it can be pierced easily with a straw while maintaining the buckling strength of the liquid paper container, and has sufficient heat seal strength and does not decrease the laminate adhesive strength. There has been a desire for liquid paper container films and liquid paper container materials that can provide excellent paper containers.

As a result of intensive studies to solve the above problems, the present inventors have created a liquid paper container using a liquid paper container material containing a specific polyolefin resin and having an oriented film. Thus, the inventors have found that the above problems can be solved, and have completed the present invention.
That is, the biaxially stretched laminated polyolefin film of the present invention is
A biaxially oriented laminated polyolefin film having a plane orientation index of 0.6 or less, wherein a biaxially oriented oriented polyolefin film II layer is laminated on at least one side of the polyolefin film I layer,
(1) Polyolefin 75-1 whose polyolefin film I layer has a melting point of 130-145 ° C.
00% by weight, and a polyolefin having a melting point of 154-164 ° C., 0-25% by weight,
(2) Polyolefin 20 in which a biaxially oriented oriented polyolefin film II layer has a melting point of 154 to 164 ° C., a polyolefin of 50 to 80% by weight, and a melting point of 105 to 145 ° C.
Consisting of ~ 50% by weight,
A biaxially stretched laminated polyolefin film for a liquid paper container.

Also, this biaxially stretched laminated polyolefin film for liquid paper containers has an MD, TD elastic modulus in the range of 1200 to 2200 MPa, a film piercing strength of 2 to 6 N, and a needle for measuring the film piercing strength. The elongation rate until penetrating through the film may be 4% or less. Furthermore, when both sides of the film are laminated, the laminate adhesive strength on both sides may be 1.5 N / 15 mm or more. In addition, these biaxially stretched laminated polyolefin films for liquid paper containers are at least from the outermost layer to the sealant B layer, printing layer, paper layer, aluminum foil layer, biaxially stretched laminated polyolefin film layer for liquid paper containers of the present invention, sealant It is preferably used as a constituent member of a liquid paper container material obtained by laminating each layer in the order of the A layer, and such a liquid paper container material is preferable as a material for producing a liquid paper container by aseptic packaging.

The biaxially stretched laminated polyolefin film for liquid paper containers of the present invention has a higher elastic modulus than conventional unstretched polyolefin films used in the construction of paper containers, and should be used in components of liquid paper container materials. Thus, the liquid paper container made from this material has a high buckling strength. For this reason, the thinning of each member constituting the conventional liquid paper container material,
Thin film can also be realized. Moreover, the piercing property by a straw is good, and there is sufficient heat seal strength, and the laminate adhesive strength does not decrease.
Therefore, the biaxially stretched laminated polyolefin film for liquid paper containers of the present invention can provide a paper container with excellent strength while using an inexpensive biaxially stretched polyolefin film. It can be suitably used as a material for a liquid paper container material, particularly an aseptic liquid paper container.

The biaxially stretched laminated polyolefin film for liquid paper containers of the present invention has a plane orientation index of 0.6 or less, in which a biaxially oriented oriented polyolefin film II layer is laminated on at least one side of a polyolefin film I layer. It is a biaxially stretched laminated polyolefin film. The polyolefin film I layer is composed of 75 to 100% by weight of a polyolefin having a melting point of 130 to 145 ° C. (hereinafter also referred to as resin A) and 0 to 25% by weight of a polyolefin having a melting point of 154 to 164 ° C. (hereinafter also referred to as resin B). . Considering the elastic modulus and buckling strength of the biaxially stretched laminated polyolefin film, resin B is added to the resin constituting the polyolefin film I layer.
It is preferable to contain 5 wt% or less. By containing 25% by weight or less of the resin B, the straw piercing property is good, the elastic modulus is large, and the buckling strength is excellent.

Although it is possible to improve the degree of orientation of the biaxially oriented oriented polyolefin film II layer by the draw ratio and thickness and increase the film strength and elastic modulus, there is an upper limit to the draw ratio that can be biaxially stretched. In the case of a general sequential biaxial stretching step, the stretching ratio is a mechanical ratio, 3 to 8 times in the longitudinal direction (the longitudinal direction of the film: hereinafter abbreviated as MD), and the transverse direction (direction orthogonal to the longitudinal direction of the film: (Hereinafter abbreviated as TD) in the range of 5 to 12 times, and the upper limit of the area machine magnification which is the product of the MD machine magnification and the TD machine magnification is about 100 times. If the upper limit of MD mechanical magnification and TD mechanical magnification and the upper limit of area mechanical magnification are exceeded, the thickness accuracy of the biaxially stretched film is lowered, or the uniaxially stretched sheet or the biaxially stretched film is easily broken during film formation. As a result, productivity decreases. Further, the thickness of the biaxially oriented oriented polyolefin II layer described later has an upper limit due to the piercing property by a straw.

In addition, by containing 25% by weight or less of the resin B, the biaxially oriented oriented polyolefin film II layer and the resin constituting the polyolefin film I layer are produced in the production of the biaxially stretched laminated polyolefin film for liquid paper containers. Since the temperature range that can be stretched with the constituent resin approaches, as a result, the common stretchable temperature range can be expanded, so that the film forming property is stabilized. In particular, when a biaxially oriented oriented polyolefin film II layer is provided on one side of the polyolefin film I layer, when MD stretching is performed with a general speed difference between rolls, the low melting point resin roll constituting the polyolefin film I layer Can be prevented. The polyolefin constituting the polyolefin film I layer is not particularly limited as long as its melting point is satisfied, and any material may be used.

Specific examples of the resin A include a propylene-α-olefin copolymer having a monomer unit based on an α-olefin other than propylene of 2.5 wt% or more and less than 10 wt%, or a mixture of these polymers. It is done. Examples of the α-olefin include ethylene and 1-
Butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-
Examples include decene and 4-methyl-1-pentene. The copolymer may be any of a random polymer, a block polymer, and a graft polymer. Among them, in view of excellent straw piercing property, propylene-ethylene random copolymer, propylene-
Ethylene block copolymers and propylene-ethylene-butene copolymers are preferred.

Examples of the resin B include a propylene homopolymer, a propylene-α-olefin copolymer containing less than 3% by weight of a monomer unit based on an α-olefin other than propylene, or a mixture of these polymers. Examples of the α-olefin include ethylene,
1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,
Examples include 1-decene and 4-methyl-1-pentene.

Among them, considering the film strength of the resulting film, propylene homopolymer,
Or the propylene-ethylene random copolymer whose monomer unit based on ethylene is 1 weight% or less is preferable. In order to further improve the straw piercing property, it is preferable to add 0.03 to 5% by weight of a crystal nucleating agent to the polyolefin resin constituting the polyolefin film I layer. Examples of the crystal nucleating agent include talc, polycyclopentene, benzylidene sorbitol derivatives, and high-density polyethylene.

Resin constituting the biaxially oriented oriented polyolefin film II layer has a melting point of 154-16
Polyolefin at 4 ° C. (hereinafter also referred to as “resin C”) 50 to 80 wt%, and melting point 105 to 1
It consists of 20 to 50% by weight of 45 ° C. polyolefin (hereinafter also referred to as resin D). When the resin D constituting the biaxially oriented oriented polyolefin film II layer is less than 20% by weight, the temperature range that can be stretched is expanded, the corona discharge treatment effect is increased, and the biaxially oriented oriented polyolefin film Interfacial strength is improved by relaxing the interface separation state due to the orientation difference between the II layer and the polyolefin film I layer, and the transparency of the interface is improved. The transparency and surface smoothness of the biaxially oriented oriented polyolefin film II itself The effect on improving the performance is small.

Since the biaxially oriented oriented polyolefin film II layer having a resin D of less than 20% by weight has a large melting point difference from the polyolefin film I layer, stretching is performed when MD stretching and TD stretching are performed in the biaxial stretching process described later. The temperature range that can be stretched together is a biaxially oriented oriented polyolefin film II layer resin and polyolefin film I layer resin laminated together. It will be narrow. Further, when a biaxially oriented oriented polyolefin film II layer is provided on one side of the polyolefin film I layer, the resin D constituting the biaxially oriented oriented polyolefin film II layer is 20
If it is less than% by weight, the stretching temperature cannot be set low, and when MD stretching is performed with a general speed difference between rolls, fusion of the low melting point resin constituting the polyolefin film I layer to the roll occurs. Cheap.

However, by containing 20% by weight or more of the resin D in the resin constituting the biaxially oriented oriented polyolefin film II layer, it plays the role of a stretching plasticizer for the resin C, and both of the above-described stretching is possible. Since the temperature range approaches, as a result, the common stretchable temperature range can be expanded and the film formation is stabilized. When the resin D constituting the biaxially oriented oriented polyolefin film II layer exceeds 50% by weight, the orientation of the biaxially oriented oriented polyolefin film II layer is low and the piercing property by the straw is satisfied. The film strength and elastic modulus of the biaxially stretched laminated polyolefin film for liquid paper containers cannot be obtained. Moreover, since the heat resistance of the whole resin which comprises the oriented polyolefin film II layer by which biaxial orientation was carried out will fall too much, the film surface will be whitened at the time of the heat processing mentioned later.

Expansion of temperature range that can be stretched and increase of corona discharge treatment effect, improvement of interfacial strength by relaxing interface separation state due to orientation difference between biaxially oriented oriented polyolefin film II layer and polyolefin film I layer, and interface part Taking into account the improvement of the transparency of the biaxially oriented oriented polyolefin film II layer itself, and the improvement of the transparency and surface smoothness of the biaxially oriented oriented polyolefin film II layer itself, the resin D contained in the resin constituting the biaxially oriented oriented polyolefin film II layer It is preferable to contain 25 to 40% by weight.

Biaxially stretched laminated polyolefin film for liquid paper container, for example, sealant B layer, printed layer, polyolefin B layer, paper layer, polyolefin A layer, aluminum foil layer, biaxially stretched laminated polyolefin film layer for liquid paper container of the present invention When used as a material for a liquid paper container in which the layers are laminated in the order of the sealant A layer, the biaxially stretched laminated polyolefin film for a liquid paper container is substantially laminated on both surfaces.

By the way, since the biaxially stretched laminated polyolefin film for liquid paper containers of the present invention has a plane orientation coefficient of 0.6 or less by heat treatment described later, the orientation of the film is lowered. In such a film whose orientation has been lowered, the additive contained in the resin of the film, the low molecular weight component of the resin, etc. are likely to bleed. Although a strong one can be obtained, the laminate adhesion performed next often results in a decrease in laminate adhesive strength.

The cause of this is that the heat during the first single-sided lamination activates the molecular movement of additives and low molecular weight components of the resin in the film resin, and the other single-sided film surface enters the film resin. Additives and low molecular weight components of the resin bleed and cover the surface in large quantities, thus inhibiting the surface treatment by corona discharge treatment applied to the film surface and reducing the wetting index, or the bleed material itself This is considered to be because the laminate adhesion is inhibited and the laminate adhesion strength is lowered.

However, the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention contains 20 to 50% by weight of the resin D constituting the biaxially oriented oriented polyolefin film II layer, and has a surface treatment effect by corona treatment. Since it is large, a decrease in wetness index is suppressed, and a strong laminate strength can be obtained on both sides. For this reason, the lamination adhesive strength when laminating the sealant A layer and the aluminum foil layer is increased. Moreover, the strength fall by the fall of the biaxial orientation which arises by addition of this resin D can be prevented because content of resin D which comprises the oriented polyolefin film II layer by which biaxial orientation was carried out shall be 50 weight% or less. The polyolefin constituting the polyolefin film II layer is not particularly limited as long as its melting point is satisfied, and any material may be used.

Specific examples of the resin C include a propylene homopolymer, a propylene-α-olefin copolymer containing less than 3% by weight of a monomer unit based on an α-olefin other than propylene, or a mixture of these polymers. It is done. Examples of the α-olefin include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4-methyl-1-pentene, and the like. be able to. Among these, considering the film strength of the resulting film, a propylene homopolymer or a propylene-ethylene random copolymer having an ethylene-based monomer unit of 1% by weight or less is preferable.

Examples of the resin D include a propylene-α-olefin copolymer having a monomer unit based on an α-olefin other than propylene of 3 wt% or more and less than 30 wt%, or a mixture of these polymers. Examples of the α-olefin include ethylene, 1-butene, 1
-Pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4
-Methyl-1-pentene and the like can be mentioned. The copolymer may be any of a random polymer, a block polymer, and a graft polymer. In consideration of the performance described later, it is preferable to mix a propylene-ethylene-butene copolymer, an ethylene-propylene copolymer, an ethylene-butene copolymer, and a propylene-butene copolymer.

The intrinsic viscosity of the resin A, resin B, resin C, and resin D is generally 0.5 to 5 dl / g.
The thing of the range of is used. Moreover, the melt mass flow rate of Resin A, Resin B, Resin C, and Resin D is 0.5 g / 10 min to 25 g when melted at 230 ° C. in consideration of obtaining a suitable biaxially stretched laminated polyolefin film for liquid paper containers. A range of / 10 minutes is preferable. When the melt mass flow rate is less than 0.5 g / 10 minutes, the mechanical load during production becomes too large. On the other hand, when the melt mass flow rate exceeds 25 g / 10 minutes, the thickness accuracy after stretching of the polyolefin resin decreases. .

In addition, the resin constituting the polyolefin film I layer and the resin constituting the biaxially oriented oriented polyolefin film II layer may contain various additives such as an antistatic agent, an antiblocking agent, and a crystal nucleating agent as necessary. It is preferable to mix.
The biaxially stretched laminated polyolefin film for a liquid paper container of the present invention has a plane orientation index of the biaxially stretched laminated polyolefin film as a whole of 0.6 or less, preferably considering the better straw piercing property and buckling strength. It is preferably 0.5 or less, more preferably 0.45 or less.

When the plane orientation index of the entire biaxially stretched laminated polyolefin film exceeds 0.6, when the biaxially stretched laminated polyolefin film for a liquid paper container is used in the member constituting the paper container, the buckling strength of the entire paper container is the target However, the straw piercing property is inferior.
In the present invention, the plane orientation index is an index representing the degree of plane orientation of a polypropylene crystal 010 plane obtained by an X-ray diffraction method to a plane parallel to the laminated film plane.

Specifically, the biaxially stretched laminated polyolefin film for liquid paper containers is rotated at high speed around an axis perpendicular to the film surface, and X-rays are incident from the direction perpendicular to the film surface to measure the diffraction intensity. The obtained X-ray diffraction intensity curve was separated into an amorphous peak, a crystalline peak, and each crystalline peak, and 111 reflection (2θ = 21.4 °) from the polypropylene crystal (α crystal).
And the ratio of the peak intensity of 040 reflection (2θ = 17.1 °).
Plane orientation index P010 = log {1.508 × I (111) / I (040)} (1)
However,
I (111): 111 reflection peak intensity (counts)
I (040): 040 reflection peak intensity (counts)

Here, the coefficient of 1.508 in equation (1) is Z.Mencik (Z.Mencik, Journal of Macromoleculer
Science, Physics B6, 101 (1972)), intensity ratio I (040) / I (111) = 16.9 / when polypropylene crystals are completely randomly oriented. 77.5 = 1.
508 (the reciprocal of the value of I (111) / I (040)). For example, if the polypropylene crystal 010 plane of the measured sample is completely randomly oriented with respect to the film plane, the value of [P010] is 0, and the polypropylene crystal 010 plane is oriented parallel to the film plane. [P 0
The value of [10] becomes large. Conversely, if the 010 plane is oriented perpendicular to the film plane, [P010] becomes a negative value.

The plane orientation index is a biaxially oriented laminated polyolefin film for liquid paper containers in which the biaxially oriented oriented polyolefin film II layer is laminated on one side, but the biaxially oriented oriented polyolefin film II layer is laminated on both sides. In the case of the biaxially stretched laminated polyolefin film for liquid paper containers, the thickness of the biaxially oriented oriented polyolefin film II layer and the above-described resin A and resin constituting the biaxially stretched laminated polyolefin film for liquid paper containers B, Resin C
Adjusted by processing conditions such as type and amount of resin D, sheet extrusion temperature in biaxial stretching process, MD stretching temperature, MD stretching ratio, TD stretching temperature, TD stretching ratio, TD heat treatment temperature, tenter rail relaxation rate, etc. can do. For example, if a polyolefin resin having high crystallinity is stretched at a high magnification at a low temperature, the plane orientation coefficient is increased. Conversely, if a polyolefin resin having low crystallinity is stretched at a low magnification at a high temperature, the plane orientation coefficient is decreased. Further, when the film is subjected to high-temperature heat treatment in a tenter heat treatment zone, or the rail pattern after stretching is adjusted with a tenter to increase the relaxation rate, the plane orientation coefficient further decreases.

In the present invention, the polyolefin film I layer is considered to be substantially non-oriented or slightly oriented. That is, the resin B in the resin constituting the polyolefin film I layer described above is present in the resin A as the main component, but the biaxially stretched laminated polyolefin film for liquid paper containers of the present invention is the polyolefin film I layer. In order to obtain non-orientation by melting the resin A in the heat treatment, the resin B having a high melting point is not melted in the melted resin A during the heat treatment, and the molecules of the resin B maintain some orientation. Thus, the entire polyolefin film I layer is considered to be substantially in a non-orientated state or a slightly oriented state.

In the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention, the polyolefin film I layer and / or the biaxially oriented oriented polyolefin film II layer are:
Each may be a single layer or multiple layers.

The biaxially oriented oriented polyolefin film II layer may be laminated on at least one side of the polyolefin film I layer. When the biaxially oriented oriented polyolefin film II layer is laminated on one side, the other side of the polyolefin film I layer may be laminated with a uniaxially oriented polyolefin film layer or a non-oriented polyolefin film layer. Liquid capable of producing a liquid paper container having the desired straw piercing property, buckling strength, etc. if a biaxially oriented oriented polyolefin film II layer is laminated on at least one side of the polyolefin film I layer A biaxially stretched laminated polyolefin film for paper containers is obtained.

Here, when the biaxially oriented oriented polyolefin film II layer of the biaxially oriented laminated polyolefin film for liquid paper containers is laminated on both surfaces of the polyolefin film I layer, the biaxially oriented laminated polyolefin film for liquid paper containers In particular, since the thickness accuracy is excellent, it is possible to obtain a biaxially stretched laminated polyolefin film for a liquid paper container having excellent surface gloss and suitability for secondary processing. In the case where the biaxially oriented laminated polyolefin film for a liquid paper container is a biaxially oriented oriented polyolefin film II layer laminated on only one side of the polyolefin film I layer, than when laminated on both sides Although the thickness accuracy is slightly inferior, it can be used without any problem.

The thickness of the biaxially stretched laminated polyolefin film for liquid paper containers used in the present invention is not particularly limited, but considering that it has both straw piercing properties and film strength, it may be 10 to 80 μm thick. preferable. Among them, the thickness is preferably set to 15 to 40 μm considering that it is a constituent member of a liquid paper container material for producing a liquid paper container having both a straw piercing property, a buckling strength and a cost, which will be described later. is there.
On the other hand, the ratio between the thicknesses of the biaxially oriented oriented polyolefin film II layer and the polyolefin film I layer can be arbitrarily selected according to the application. For example, if the biaxially oriented oriented polyolefin film II layer is thickened, the strength of the biaxially stretched laminated polyolefin film for liquid paper containers is improved, and if the polyolefin film I layer is thickened, the straw piercing property is improved. In general, the thickness of the polyolefin film I layer is selected from the range of 70 to 95%, particularly preferably 75 to 95% of the thickness of the entire film.

The biaxially oriented oriented polyolefin film II layer used in the present invention has a thickness of 12 μm
Or less, more preferably 10 μm or less. If it exceeds 12 μm, the liquid paper container made from the liquid paper container material having this as a constituent member will bend the tip of the straw when piercing the straw, or the upper surface of the paper container will be dented,
The piercing ability of the straw is insufficient. The thickness of the biaxially oriented oriented polyolefin film II layer referred to here is the sum of all the thicknesses of the biaxially oriented oriented polyolefin film II layer constituting the biaxially oriented laminated polyolefin film for liquid paper containers. When the oriented oriented polyolefin film II layer is laminated on both sides, the thickness of the biaxially oriented oriented polyolefin film II layer on one side is preferably 6 μm or less, and more preferably 5 μm or less.

As described above, the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention is used as a constituent member of a liquid paper container material, thereby giving a liquid paper container having excellent buckling strength. Moreover, it has a low piercing strength, has a straw piercing property, is excellent in heat seal strength and laminate strength, and has hand cutting properties in any direction from anywhere in the surface.
When the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention in a tape shape is cut with a tape cutter, it can be easily cut leaving a blade shape.

The biaxially stretched laminated polyolefin film for a liquid paper container of the present invention takes into account the straw piercing property when used as a paper container member, and the buckling strength required for the entire paper container when an external force is applied to the paper container. The film strength preferably has the following properties.
That is, the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention has MD and T
The elastic modulus of D is 1200 to 2200 MPa, and the piercing strength is 2 to 2 in the piercing strength measurement.
It is preferable that the elongation percentage of the film until it is 6N and the hole is opened by piercing is 4% or less.

If the elastic modulus is 1200 MPa or more, a liquid paper container having a target buckling strength can be obtained when this is used as a constituent member of the liquid paper container material. The piercing strength is 2-6
If it is in the range of N and the elongation rate of the film is only 4% or less when the puncture strength is measured, it can be pierced easily with a straw.

Furthermore, when the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention is laminated on both sides of the film, it is preferable that the lamination adhesive strength on both sides is 1.5 N / 15 mm or more. When laminating on both sides of the biaxially stretched laminated polyolefin film for liquid paper containers, when the laminate adhesive strength on both sides is 1.5 N / 15 mm or more, when used as a component of the liquid paper container material, A liquid paper container with excellent strength that does not cause separation between this biaxially stretched polyolefin film for liquid paper containers and, for example, a sealant layer or an aluminum foil layer can be obtained. The contents can be prevented from leaking by such external force.

The biaxially stretched laminated polyolefin film for a liquid paper container according to the present invention is the liquid paper container material according to claim 4, that is, at least from the outermost layer side, a sealant B layer, a printed layer, a paper layer, an aluminum foil layer, and a liquid according to the present invention. Liquid paper container material characterized by laminating each layer in the order of biaxially stretched laminated polyolefin film layer for paper container and sealant A layer, for example, sealant B layer, printing layer, polyolefin B layer, paper layer, polyolefin A layer , An aluminum foil layer, a biaxially stretched laminated polyolefin film layer for a liquid paper container of the present invention, and a sealant A layer can be used as a liquid paper container material in which the respective layers are laminated in this order. In this case, the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention is formed by laminating an aluminum foil on one side and a sealant A layer on the other side. Both sides are laminated.

Oriented polyolefin film biaxially oriented only on one side of polyolefin film I layer
When the biaxially stretched laminated polyolefin film for liquid paper containers on which the II layer is laminated is used as the liquid paper container material, either the polyolefin film I layer or the oriented polyolefin film II layer may be disposed on the inside, preferably In order to obtain good straw piercing property, the polyolefin film I layer should be disposed on the inner surface side. Further, when the resin constituting the sealant B layer and the heat sealable resin are selected as the resin constituting the polyolefin film I layer, or the resin constituting the polyolefin film I layer and the heat as the resin constituting the sealant B layer. When a resin that can be sealed is selected, the polyolefin film I layer can be substituted for the sealant A layer and the sealant A layer can be omitted. In this case, since the polyolefin film I layer side of the biaxially stretched laminated polyolefin film for liquid paper containers is a heat seal layer, it is preferable not to perform surface treatment by corona discharge treatment.

In the present invention, the resin used for the sealant A layer is not particularly limited as long as it has heat sealability. Examples include low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, propylene-butene copolymer, propylene homopolymer, propylene-ethylene random. Copolymer, propylene-ethylene block copolymer, propylene-ethylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer Examples thereof include polymers such as polymers, ethylene-ethyl acrylate copolymers, ethylene-methyl methacrylate copolymers, cyclohexane dimethanol-modified polyethylene terephthalate copolymers, and mixtures thereof.

The above-mentioned sealant A layer is used as the innermost layer of the liquid paper container when the liquid paper container material is a liquid paper container material having the biaxially stretched laminated polyolefin film for liquid paper container of the present invention as a constituent member. It becomes a layer in contact with things. Therefore, regarding the selection of the resin for the sealant A layer,
In order not to impair the taste and flavor of the contents, select a resin that has no or reduced additives such as antioxidants, lubricants, antiblocking agents, chlorine scavengers, and antistatic agents in the resin. Is desirable.

In particular, as the resin for the sealant A layer, among the above-mentioned resins, when heat is applied to a liquid paper container beverage that is excellent in heat sealability and is filled with a beverage using a vending machine with a warmer or a warmer Also, it is preferable to use an ethylene-α-olefin copolymer that generates little resin odor over time.

The sealant A layer need not be a single layer as long as only the heat seal layer is made of the above-described resin, and may be a multi-layered film formed by a co-pressing method or the like, for example. For example, when an unstretched multilayer film is used for the sealant A layer, the resin of the other layer is particularly limited if there is a layer using the above-described heat-sealable resin in the innermost layer side of the liquid paper container. It is not something. The thickness of the sealant A layer is not particularly limited, but is generally selected from a thickness of 3 to 50 μm.

In the liquid paper container material using the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention, the aluminum foil layer has a role of blocking the transmission of oxygen and light and preventing the contents from being oxidized and deteriorated by light. In this case, a gas barrier layer may be interposed instead of the aluminum foil layer. However, when the contents are easily deteriorated by light, it is necessary to use a gas barrier material having a light shielding property or to separately provide a light shielding layer. The thickness of the aluminum foil layer is not particularly limited, but is usually 7-12.
Those having a thickness of μm are preferably used.

Moreover, the polyolefin A layer laminated | stacked on an aluminum foil layer is used for adhesion | attachment of a paper layer and an aluminum foil layer. The polyolefin resin constituting the polyolefin A layer is not particularly limited as long as it has adhesiveness. Usually, low density polyethylene or linear low density polyethylene is suitably used. The thickness of the polyolefin A layer is preferably 10 to 30 μm. Further, since the polyolefin A layer substantially plays a role of bonding when the aluminum foil layer and the paper layer are laminated, an adhesive layer using an adhesive may be provided instead of the polyolefin A layer. The paper used for the paper layer is not particularly limited, but paperboard made from virgin pulp of softwood and hardwood having a basis weight of 150 to 400 g / m ² can be suitably used.

The polyolefin B layer is laminated with the paper layer, and after the printing layer is applied, the sealant B layer is laminated. The polyolefin B layer serves as a printing substrate. When printing, it is possible to print directly on the paper layer, and this layer may be unnecessary. However, rather than printing directly on paper with inferior surface smoothness, once the polyolefin B layer is laminated on the paper and surface smoothness is improved, printing with a shallow plate depth can be easily performed. Thus, since extremely fine printing such as gravure printing can be performed, the appearance of printing on the paper container is finally very good.

As the resin constituting the polyolefin B layer, low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, propylene-butene copolymer, propylene homopolymer , Propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-ethylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-
Examples thereof include polymers such as methacrylic acid copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl methacrylate copolymers, and mixtures thereof. The polyolefin B layer preferably has a thickness of 5 to 30 μm.

In consideration of the display effect of the contents that become various products, the print layer displays the product name, raw material, content, recycle mark, and the like. The printing method is not particularly limited, and the above gravure printing, letterpress printing, offset printing and the like are used.
When the sealant B layer is processed into a paper container, the liquid paper container material having this as a constituent member is used.
In order to heat-seal the back-pasted part (vertical seal part) of the paper container in the form of an envelope, it is heat-sealed with the sealant A layer in the back-pasted part (vertical seal part) as a substantial form.

The resin constituting the sealant B layer is not particularly limited, and low-density polyethylene is preferably used. However, linear low-density polyethylene, high-density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer are also used. Polymer, propylene-butene copolymer, propylene homopolymer, propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-ethylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene- Polymers such as acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, and mixtures thereof are preferably used. it can. The sealant B layer is preferably the same as the resin used for the sealant A layer or one having excellent heat sealability with the sealant A layer. The thickness of the sealant B layer is 10-50μm
It is preferable that

The biaxially stretched laminated polyolefin film for liquid paper containers of the present invention can be suitably produced by the method shown below. First, a sheet is obtained using at least two or more co-extrusion dies, and then uniaxially stretched to obtain a multilayer uniaxially stretched sheet. Further, biaxial stretching is performed in a direction orthogonal to the uniaxial stretching of the multilayer uniaxially stretched sheet. At this time, resin A having a melting point of 130 to 145 ° C. contained in the resin constituting the polyolefin film I layer in the biaxially stretched tenter is melted by a tenter heat treatment to be contained in the polyolefin film I.
The layer is substantially non-oriented. On the other hand, it is 0 for the resin constituting the polyolefin film I layer.
Resin B having a melting point of 154 to 164 ° C. contained in an amount of ˜25 wt% makes the polyolefin film I layer substantially non-oriented or slightly oriented.

Further, in the biaxially oriented oriented polyolefin film II layer, the resin constituting the biaxially oriented oriented polyolefin film II layer by tenter heat treatment is 20 to 50% by weight.
The contained resin D having a melting point of 105 to 145 ° C. is relaxed in orientation and partially melted.
Since the orientation of the resin C at ˜164 ° C. remains, as a result, the biaxially stretched laminated polyolefin film for a liquid paper container of the present invention is obtained.

Specifically, the preferred production method described above is exemplified by a multilayer die or a single layer die so that a biaxially oriented oriented polyolefin film II layer resin is laminated on one or both sides of a polyolefin film I layer resin. There is a method in which a multi-layer sheet obtained by a co-pushing method using a feed block method is stretched to MD, then stretched to TD, and then subjected to tenter heat treatment in a tenter heat treatment zone. The stretching ratio in the stretching is not particularly limited, but is generally selected from the range of 4 to 8 times for MD and 6 to 13 times for TD.
Among them, considering the buckling strength and straw piercing property of the liquid paper container made from the liquid paper container material using this biaxially stretched laminated polyolefin film as a constituent member,
The MD draw ratio is more preferably 5.0 to 7.5 times.

By setting the MD draw ratio to 5.0 times or more, the elongation rate of the film until the hole is pierced by piercing at the time of piercing strength measurement of the obtained biaxially stretched laminated polyolefin film for liquid paper containers is 4% or less. This makes it easier to pierce the multilayer film with a straw. On the other hand, when the MD draw ratio exceeds 7.5 times, the MD orientation becomes too strong, the mechanical load becomes large in the TD stretch of the next step, and the thickness accuracy of the resulting biaxially stretched laminated polyolefin film for liquid paper containers is inferior.

The MD stretching temperature varies depending on the selection and mixing ratio of the resin A, resin B, resin C, and resin D constituting the polyolefin film I layer and the biaxially oriented oriented polyolefin film II layer. If draw ratio is adopted, MD draw temperature is 125-
It can be suitably stretched in the range of 150 ° C. Moreover, MD stretchable temperature range expands 5-15 degreeC by the effect of melting | fusing point 105-145 degreeC of resin D contained 20-20 weight% in resin which comprises the oriented polyolefin film II layer by which biaxial orientation was carried out.

The TD stretching temperature is not particularly limited because it is affected by the TD preheating temperature.
When TD preheating temperature is set to 175-185 degreeC, TD extending | stretching temperature can carry out TD extending | stretching suitably in the range of 145-160 degreeC. The TD stretching temperature is determined by the amount of heat medium to be heated and the amount of heat applied to the film, and the amount of heat given to the film is 75 to 100% by weight with respect to the resin constituting the polyolefin film I layer at the above TD preheating temperature and TD stretching temperature. Melting point contained 130-14
It is preferable not to melt the resin A at 5 ° C. When the above-mentioned resin A is melted at the TD preheating temperature and the TD stretching temperature, the thickness profile by the film thickness meter after TD stretching is
Since physical change due to melting of the polyolefin film I layer and thickness change due to stretching are simultaneously performed, it becomes difficult to adjust the thickness.

The tenter heat treatment temperature in the tenter heat treatment zone is the polyolefin film I
There is no limitation as long as the resin A having a melting point of 130 to 145 ° C. contained in the resin constituting the layer is set to be non-oriented or nearly non-oriented by the tenter heat treatment, for example, polyolefin film I What is necessary is just to process it more than melting | fusing point of a layer, and even if it is temperature higher than melting | fusing point of the oriented polyolefin film II layer by which biaxial orientation was carried out, what is necessary is just to control and process a tenter heat processing time, and as a result resin A The tenter heat treatment temperature and the tenter heat treatment time may be selected so that the biaxial orientation of the resin C remains in a non-oriented or nearly non-oriented state.

In addition, the resin D having a melting point of 105 to 145 ° C. contained in the resin constituting the biaxially oriented oriented polyolefin film II layer by 20 to 50% by weight is relaxed and partially partially melted by the tenter heat treatment. Increase interfacial strength between layers. It also improves the corona treatment effect and transparency. If the tenter heat treatment temperature is high, the straw piercing property will be good, and if it is low, the film strength will be improved. Preferably, the tenter heat treatment temperature is selected from 140 ° C to 190 ° C.

The plane orientation index of the biaxially stretched laminated polyolefin film for liquid paper containers of the present invention can be reduced to 0.6 or less by the tenter heat treatment. If the plane orientation index exceeds 0.6 even after sufficient heat treatment in the tenter heat treatment, the biaxially oriented oriented polyolefin film II layer can be further thinned, or the biaxially oriented oriented polyolefin By adopting resin with low crystallinity for resin C and resin D constituting the film, the plane orientation index is 0.6.
It can be: Also, for liquid paper containers under processing conditions such as sheet extrusion temperature, MD stretching temperature, MD stretching ratio, TD stretching temperature, TD stretching ratio, TD heat treatment temperature, tenter rail relaxation rate, etc. The MD and TD orientation of the biaxially stretched laminated polyolefin film can be tensioned or relaxed to control the plane orientation index.

Moreover, the tenter heat treatment time in the tenter heat treatment is not particularly limited, and an optimum time may be determined according to the temperature of the tenter heat treatment. Usually 6-30
Seconds. Considering the stable film-forming property among the above tenter heat treatment conditions, the resin used,
It is preferable to employ the maximum tenter heat treatment time depending on the purpose.

The liquid paper container material comprising the biaxially stretched laminated polyolefin film for liquid paper container as a constituent member may be obtained by any method.
For example, sealant B layer, printing layer, polyolefin B layer, paper layer, polyolefin A layer,
Biaxially oriented laminated polyolefin film layer for liquid paper containers having a plane orientation index of 0.6 or less, wherein a biaxially oriented oriented polyolefin film II layer is laminated on at least one surface of an aluminum foil layer and a polyolefin film I layer In the case of a liquid paper container material in which the layers are laminated in the order of the sealant A layer, the biaxially stretched laminated polyolefin film for liquid paper container is obtained first by the above-described method, and the anchor coating agent is applied on one surface thereof After the extrusion laminating method in which the sealant A layer is directly laminated on the anchor coat surface of the biaxially stretched laminated polyolefin film for liquid paper containers using a T-die from an extruder, or once the sealant A layer is formed into a film , Sealant by the method of laminating to biaxially stretched laminated polyolefin film for liquid paper containers using adhesive The layers were laminated, and then obtain a laminate 1 by laminating an aluminum foil layer on the other surface of the biaxially oriented laminated polyolefin film for liquid cartons.

Next, a polyolefin B layer is laminated on the paper layer, and printing is performed on the polyolefin B layer side to obtain a printed matter 1. Next, the printed material 1 is subjected to a hole punching process as a straw piercing opening. The aluminum foil side of the laminate 1 is laminated on the polyolefin A layer while extruding and laminating the polyolefin A layer on the paper layer side of the printed matter 1 provided with a straw piercing opening. Further, the sealant B layer is extruded and laminated on the printed layer side of the printed matter 1 to complete the liquid paper container material.
The above is a general method for producing a liquid paper container material, but any method may be used as long as it results in the form constituting the liquid paper container material of the present invention. Alternatively, each layer may be laminated using an adhesive and manufactured while partially constituting.

The liquid paper container material of the present invention can be used as a material for any type of liquid paper container, but is particularly suitable as a material for an aseptic type liquid paper container obtained by aseptic packaging. In this case, a crease line is attached to the liquid paper container material in a continuous state obtained in the manner described above with a cleaver, and the liquid paper container material with the crease line is supplied to an aseptic filling machine, for example, Shikoku. Continuously sterilized with hydrogen peroxide using a Kakoh UP-FUJI filling machine, etc., sterilized with hydrogen peroxide, and then longitudinally sealed in a sterile chamber to form a tube. Filled material (in liquid paper container material)
Contents), a horizontal line seal is applied at predetermined intervals in the horizontal direction of the tube-shaped liquid paper container material, and the liquid paper container material is cut along the horizontal line seal portion and folded along the crease. Then, it is molded into a final shape to obtain a liquid paper container.

The shape of the liquid paper container is not particularly limited. For example, the above aseptic type liquid paper container is not limited to a brick shape but may be a polygonal column shape or an asymmetric shape as long as it can be formed by the filling machine, and the upper and lower shapes thereof may be deformed. May be. Moreover, the obtained liquid paper container may be provided with a straw hole or an opening at an appropriate position, or may be provided with a stopper, a pull tab, a cut, or the like, if necessary. Furthermore, you may attach a straw.
<Example>

Examples are given below to specifically describe the present invention, but the present invention is not limited to these examples. In addition, the measurement in the following examples and comparative examples was performed as follows.
Physical properties of biaxially stretched laminated polyolefin film for liquid paper containers are measured at 40 ° C after production for 2 days, sampled into each measurement size, conditioned at 23 ° C and 50% RH for 24 hours, and measured under the same conditions did.
The laminate by lamination in each step was cured at 40 ° C. for 3 days after lamination, and then the temperature was 23
Conditioning was performed at 50 ° C. and RH for 24 hours, and measurement was performed under the same conditions.
(1) thickness;
The thickness was measured with a mechanical thickness meter (Micrometer OMV-25DM manufactured by Mitutoyo Corporation).
(2) transparency;
The haze of the film was measured according to JIS-Z1712.
(3) surface glossiness;
The gloss of the film surface was measured according to JIS-Z1712.
(4) Melting point of resin;
Using a differential scanning calorimeter (DSC6200R manufactured by Seiko Denshi Kogyo Co., Ltd.)
After melting at 5 ° C. and holding for 10 minutes, the temperature was lowered to 30 ° C. at a temperature drop rate of 10 ° C./min, and then the melting point was measured when the temperature was raised to 235 ° C. at a temperature rise rate of 10 ° C./min.
(5) copolymer composition;
Nuclear magnetic resonance spectrometer using (JEOL Ltd. JNM-GSX-270), o-dichlorobenzene / heavy benzene (volume 90/10) as a solvent was measured at 120 ° C. ¹³
Calculated from the C-NMR spectrum.
(6) Elastic modulus (tensile modulus);
10mm wide and 100m long so that MD and TD are long from the film.
A sample of m was cut out, adjusted using a tensile tester (AG500, manufactured by Shimadzu Corporation) so that the distance between chucks was 20 mm, and held and fixed by the chuck. A tensile test was performed at a tensile speed of 20 mm / min to prepare a tensile stress-strain curve.
The tensile modulus was calculated by the following equation using the first linear portion of the tensile stress-strain curve.
Em = Δδ / Δε
Em = tensile modulus Δδ: difference in stress due to the original average cross-sectional area of the sample between two points on the straight line Δε: difference in strain between the same two points (7) Piercing strength and until the film is pierced by piercing Elongation rate;
In accordance with the puncture strength test described in Ministry of Health and Welfare Notification No. 370 in 1959, the sample was fixed, and a semicircular needle having a diameter of 1.0 mm and a tip shape radius of 0.5 mm was pierced at a speed of 50 mm / min on the sample surface. The maximum load until the needle penetrated was measured. The elongation of the film from when the needle was stressed until it penetrated was measured.
(8) Plane orientation index;
The measurement was performed under the following conditions using an X-ray diffraction apparatus JDX-3500 manufactured by JEOL.
Target: Copper (Cu-Kα line)
Tube voltage-tube current: 40 kV-400 mA
X-ray incidence method: vertical beam transmission method Monochromatization: graphite monochromator Divergence slit: 0.2 mm
Receiving slit: 0.4mm
Detector: Scintillation counter measurement Angular range: 9.0 ° to 31.0 °
Step angle: 0.04 °
Counting time: 3.0 seconds Sample rotation speed: 120 rpm
In this case, the film is cut into 20 mm × 20 mm, and several tens of these are stacked to a thickness of about 3 m.
It was set as m, and it mounted and measured to the transmission method rotation sample stand attached to the wide angle goniometer. For peak separation, after removing the background due to air scattering or the like within a diffraction angle (2θ) range of 9 ° to 31 °, the amorphous peak and each crystalline substance are separated by a general peak separation method using a Gaussian function and a Lorentz function. Separated into peaks. The plane orientation index was calculated from the peak intensity of 040 reflection and 111 reflection by the method described above. FIG. 2 is a peak separation result of an X-ray diffraction curve of a biaxially stretched laminated polyolefin film for a liquid paper container of Example 1 which will be described later. A-B is 436 when I (040).
3 counts and CD is 1 (111) and 1259 counts.
Therefore, the plane orientation index P ₀₁₀ in this case is log (1.508 × 1259/436).
It becomes -0.361 in 3).
(9) Melt mass flow rate;
Melt mass flow rate (hereinafter abbreviated as MFR) was measured according to JIS-K7210.
(10) Straw piercing property;
Using a plastic straw, the evaluator 10 actually puts it in the straw hole of the brick paper container.
By name, the straw piercing property when pierced by hand was evaluated in the following three stages.
○ ... Easy to stab.
Δ: There is a sense of resistance, but it can pierce.
× ... I can't pierce. Or, the brick type paper container is deformed.
(11) Laminate adhesive strength;
15mm in width and 15mm in length so that the MD becomes longer from the laminated body
A sample of 0 mm was cut out, the laminated interface was peeled off by 50 mm in MD, and a peel test was performed at 90 ° peel using a tensile tester (AG500 manufactured by Shimadzu Corporation) at a pulling speed of 20 mm / min. Was measured.
(12) Wetting index;
It measured according to JIS-Z1712.
(13) Paper container buckling strength measurement;
Aseptic brick paper containers that have been filled and molded are processed using a strograph tester (Corporation)
(Toyo Seiki M2 type) placed vertically with the bottom face down and the top face with a straw hole facing up (
In the state shown in FIG. 1, the strength test was conducted under the conditions of a load cell of 1.96 kN and a compression speed of 200 mm / min, and the first peak value was defined as the buckling strength (N).
(14) Resin odor evaluation;
Aseptic type brick-type paper containers filled with activated carbon filtered water as evaluation water were heated to 60 ° C with a heater, and after 5 days and 10 days, sensory evaluation was performed by 10 evaluators. The odor was evaluated in the following five stages.
1 ... Feels almost no resin odor.
2 ... Feels a slight resin odor.
3. Feel the resin odor.
4 ... Feels the resin odor strongly.
5 ... Feels the resin odor very strongly.
<Example 1, comparative example 1>

As the resin A constituting the polyolefin film I layer, an ethylene-propylene random copolymer (4.6% by weight of ethylene-based monomer unit, melting point 135 ° C., MFR 2.1 g / 1)
0 minute) is 95% by weight, ethylene-propylene random copolymer as resin B constituting the polyolefin film I layer (ethylene monomer unit 0.4% by weight, melting point 156 ° C.,
Resin A and Resin B were mixed at a MFR of 2.3 g / 10 min) at 5% by weight to prepare a polyolefin film I resin.
As resin C constituting the biaxially oriented oriented polyolefin film II layer, an ethylene-propylene random copolymer (ethylene monomer unit 0.4 wt%, melting point 156 ° C.,
Oriented polyolefin film II biaxially oriented with 60% by weight of MFR 2.3 g / 10 min)
As resin D constituting the layer, ethylene-propylene-1-butene terpolymer (6.2% by weight of monomer units based on ethylene, 5.1% by weight of monomer units based on 1-butene, melting point 13
Resin C and Resin D were mixed at 0 ° C. and MFR 5.0 g / 10 min) to 40 wt% to prepare a biaxially oriented oriented polyolefin film II layer resin.

A multi-layer die was used to coextrude the biaxially oriented oriented polyolefin film II layer resin on both sides of the polyolefin film I layer resin to obtain an unstretched sheet.
The sheet was stretched 5.8 times in MD, then 10 times in TD, heat treated for 15 seconds at the tenter heat treatment temperature shown in Table 1, and then subjected to corona discharge treatment on both sides, and the polyolefin film I layer A biaxially stretched laminated polyolefin film for a liquid paper container having a thickness of 15 μm and a biaxially oriented oriented polyolefin film II layer laminated on both surfaces of 2.5 μm each was obtained. The physical properties of the biaxially stretched laminated polyolefin film for liquid paper containers are shown in Table 1. The biaxially stretched laminated polyolefin film for a liquid paper container treated at a tenter heat treatment temperature of 167 ° C. was used in Example 1, and the biaxially stretched laminated polyolefin film for a liquid paper container treated at a tenter heat treatment temperature of 157 ° C. was a comparative example. It was set to 1.

The wetting index of the biaxially stretched laminated polyolefin film for liquid paper containers obtained in Example 1 and Comparative Example 1 was 41 mN / m on both sides. Also, a low-density polyethylene having a thickness of 20 μm by a dry laminating method using a two-component curable ester adhesive on one side of the biaxially stretched laminated polyolefin film for liquid paper containers of Example 1 and Comparative Example 1 at a drying temperature of 80 ° C. The films were laminated to obtain a multilayer film having a thickness of 42 μm. The wetting index on the side of the biaxially stretched laminated polyolefin film for liquid paper containers of the laminated multilayer film was reduced to 39 mN / m in Example 1, and the wetting index in Comparative Example 1 was reduced to 40 mN / m.

Next, the aluminum foil having a thickness of 7 μm is dry laminated at a drying temperature of 80 ° C. using a two-component curable ester adhesive on the biaxially stretched laminated polyolefin film side of the multilayer film for a liquid paper container. A laminate 1 having a thickness of 50 μm having a three-layer structure in which a polyethylene film, a biaxially stretched laminated polyolefin film for a liquid paper container, and an aluminum foil are laminated in this order was obtained. The laminate 1 was cured for 3 days, and the laminate adhesive strength between the respective layers was measured.
The laminate adhesive strength between the low density polyethylene film of laminate 1 of Example 1 and the biaxially stretched laminated polyolefin film for liquid paper containers was 4.88 N / 15 mm. on the other hand,
The laminate adhesive strength between the aluminum foil and the biaxially stretched laminated polyolefin film for liquid paper containers was 3.51 N / 15 mm.
The laminate adhesive strength between the low density polyethylene film of the laminate 1 of Comparative Example 1 and the biaxially stretched laminated polyolefin film for liquid paper containers was 5.01 N / 15 mm. on the other hand,
The laminate adhesive strength between the aluminum foil and the biaxially stretched laminated polyolefin film for liquid paper containers was 4.34 N / 15 mm.

Next, a low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paper board having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.
Next, the printed product 1 is subjected to a punching process with a straw piercing port, and the aluminum foil side of the three-layer laminate 1 is laminated while extruding and laminating low-density polyethylene on the paper side of the printed matter 1. A laminate 2 was obtained in which printing, low density polyethylene, paper, low density polyethylene, aluminum foil, a biaxially stretched laminated polyolefin film for liquid paper containers, and a low density polyethylene film were laminated in this order. Furthermore, the low-density polyethylene is laminated on the printing surface of the laminate 2 while being extruded, and the low-density polyethylene (thickness 15 μm), printing, low-density polyethylene (thickness 15 μm), paper (basis weight 200 g / m ² ) from the outermost layer side. Paperboard), low-density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), biaxially stretched laminated polyolefin film (thickness 20 μm) for liquid paper containers, and low-density polyethylene film (thickness 20 μm). Obtained material.

The materials used at this time are as follows.
The low-density polyethylene is made of Mitsui Chemicals Co., Ltd. Mirason 16P, the low-density polyethylene film is Tamapoly Co., Ltd. AJ-1, and the paper is made of softwood and hardwood virgin pulp with a basis weight of 200 g / m ² . The paperboard and aluminum foil are JIS standard standard products 1N30, and the biaxially stretched laminated polyolefin film for liquid paper containers is the biaxially stretched laminated polyolefin film for liquid paper containers of Example 1 or Comparative Example 1. After slitting the obtained liquid paper container material into a band with a predetermined width, the aseptic packaging was performed with UP-FUJI-MA80 machine manufactured by Shikoku Koki Co., Ltd., and the contents were filled with activated carbon filtered water as sensory evaluation water A brick type paper container having a volume of 250 ml was obtained.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container. The results are shown in Table 2.
<Comparative example 2>

Table 1 shows the elastic modulus, puncture strength, and puncture elongation of a low-density polyethylene film having a thickness of 40 μm and a one-sided corona treatment having a wetting index of 38 mN / m.
Using a two-component curable ester adhesive on the corona-treated surface side of the low-density polyethylene film, a 7 μm aluminum foil was laminated at a drying temperature of 75 ° C. by the dry laminating method. A two-layered multilayer film was obtained.
After curing the two-layer multilayer film for 3 days, the low-density polyethylene is directly applied to the low-density polyethylene film with an extruder while performing ozone treatment on the low-density polyethylene film side of the two-layer multilayer film.
Extrusion lamination was performed to obtain a laminate 1 having a three-layer structure having a thickness of 70 μm and laminated in the order of an aluminum foil, a low density polyethylene film, and a low density polyethylene. The laminate adhesive strength between the aluminum foil of the laminate 1 and the low-density polyethylene film having a thickness of 40 μm is 2.54 N
/ 15 mm. On the other hand, extrusion laminated low density polyethylene and thickness 40μm
Since the laminate adhesive strength of the low density polyethylene film was strong between the film layers, a measurement sample could not be prepared and measurement was impossible.

Next, a low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paper board having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.
Next, the printed matter 1 is subjected to a punching process with a straw piercing port, and while the low density polyethylene is extruded and laminated on the paper side of the printed matter 1, the aluminum foil side of the three-layer laminate 1 is laminated, A laminate 2 was obtained that was laminated in the order of printing, low density polyethylene, paper, low density polyethylene, aluminum foil, low density polyethylene film, and low density polyethylene. Further, the low-density polyethylene is laminated on the printing surface of the laminate 2 while being extruded, and low-density polyethylene (thickness 15 μm), printing, low-density polyethylene (thickness 15 μm), paper (basis weight 200 g)
/ M ² paperboard), low density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), low density polyethylene film (thickness 40 μm), and low density polyethylene (thickness 20 μm) were laminated in this order to obtain a liquid paper container material.

The materials used at this time are as follows.
The low density polyethylene is Milason 16P manufactured by Mitsui Chemicals Co., Ltd., the low density polyethylene film is AJ-1 manufactured by Tamapoly Co., Ltd., and the paper has a basis weight of 200 g / m ² made from virgin pulp of softwood and hardwood. Paperboard and aluminum foil are JIS standard standard products 1N30. After slitting the obtained liquid paper container material into a belt with a predetermined width, U made by Shikoku Koki Co., Ltd.
Aseptic packaging was performed with a P-FUJI-MA80 machine, and a brick-type paper container having an internal volume of 250 ml was obtained by adding activated carbon filtered water as sensory evaluation water to the contents.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container. The results are shown in Table 2.
<Example 2>

As the resin A constituting the polyolefin film I layer, an ethylene-propylene random copolymer (2.8% by weight of monomer units based on ethylene, melting point 144 ° C., MFR 3.0 g / 1)
90% by weight of 0.1% by weight of benzylidene sorbitol derivative as a crystal nucleating agent at 0 minute), and ethylene-propylene random copolymer (ethylene-based monomer unit) as resin B constituting the polyolefin film I layer 0.4 wt%, melting point 156 ° C, MFR2
. 3 g / 10 min) was added 0.1% by weight of a benzylidene sorbitol derivative as a crystal nucleating agent, and 10% by weight of resin A and resin B were mixed to prepare a resin for a polyolefin film I layer.

As resin C constituting the biaxially oriented oriented polyolefin film II layer, an ethylene-propylene random copolymer (ethylene monomer unit 0.4 wt%, melting point 156 ° C.,
Oriented polyolefin film II biaxially oriented with 75% by weight of MFR 2.3 g / 10 min)
As resin D constituting the layer, ethylene-propylene-1-butene terpolymer (6.2% by weight of monomer units based on ethylene, 5.1% by weight of monomer units based on 1-butene, melting point 13
Resin C and Resin D were mixed at 0 ° C. and MFR 5.0 g / 10 min) to 25 wt% to prepare a biaxially oriented oriented polyolefin film II layer resin.

An unstretched sheet was obtained by co-extrusion using a multilayer die so that the resin of the oriented polyolefin film II layer biaxially oriented on both surfaces of the resin of the polyolefin film I layer was laminated. The sheet was stretched 7.0 times to MD, then 10 times to TD, heat treated for 15 seconds at the tenter heat treatment temperature shown in Table 1, and then subjected to corona discharge treatment on both sides, and polyolefin film I layer 24 μm A biaxially oriented laminated polyolefin film for a liquid paper container having a thickness of 30 μm and a biaxially oriented oriented polyolefin film II layer laminated on both sides of 3.0 μm was obtained. Table 1 shows the physical properties of the obtained biaxially stretched laminated polyolefin film for liquid paper containers. The resulting biaxially oriented laminated polyolefin film for liquid paper containers has a wetting index of 40 m on both sides.
N / m.

Next, using a two-component curable ester adhesive on one side of the obtained biaxially stretched laminated polyolefin film for liquid paper containers, a low density polyethylene film having a thickness of 20 μm is laminated by dry lamination at a drying temperature of 85 ° C., and a thickness of 52 μm. A multilayer film was obtained. The wetting index of the laminated multilayer film on the biaxially stretched laminated polyolefin film side for liquid paper containers is 37 mN
/ M.

Next, the aluminum foil having a thickness of 7 μm is dry-laminated on the biaxially stretched laminated polyolefin film side for the liquid paper container of the multilayer film using the same two-component curable ester adhesive, and the low density polyethylene film, the liquid paper container A biaxially stretched laminated polyolefin film and an aluminum foil were laminated in this order to obtain a laminate 1 having a three-layer structure having a thickness of 61 μm. The laminate 1 was cured for 3 days, and the laminate adhesive strength between the respective layers was measured.
The laminate adhesive strength between the layers of the low-density polyethylene film of laminate 1 and the biaxially stretched laminated polyolefin film for liquid paper containers was 3.52 N / 15 mm. On the other hand, the laminate adhesive strength between the layers of the aluminum foil and the biaxially stretched laminated polyolefin film for liquid paper containers is 2.0.
It was 5 N / 15 mm.

Next, a low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paper board having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.
Next, the printed product 1 is subjected to a punching process with a straw piercing port, and the aluminum foil side of the three-layer laminate 1 is laminated while extruding and laminating low-density polyethylene on the paper side of the printed matter 1. A laminate 2 was obtained in which printing, low density polyethylene, paper, low density polyethylene, aluminum foil, a biaxially stretched laminated polyolefin film for liquid paper containers, and a low density polyethylene film were laminated in this order. Furthermore, the low-density polyethylene is laminated on the printing surface of the laminate 2 while being extruded, and the low-density polyethylene (thickness 15 μm), printing, low-density polyethylene (thickness 15 μm), paper (basis weight 200 g / m ²⁾ Paperboard), low density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), biaxially stretched laminated polyolefin film for liquid paper containers (thickness 30 μm), and low density polyethylene film (thickness 20 μm) in this order. Obtained material.

The materials used at this time are as follows.
Low density polyethylene, both manufactured by Mitsui Chemicals, Inc. Mirason 16P, low density polyethylene film Tamapoly Co. AJ-1, paper basis weight is papermaking from virgin pulp softwood and hardwood is 200 g / m ² The paperboard and aluminum foil are JIS standard standard 1N30, and the biaxially stretched laminated polyolefin film for liquid paper containers is the biaxially stretched laminated polyolefin film for liquid paper containers obtained in Example 2. After slitting the obtained liquid paper container material into a band with a predetermined width, the aseptic packaging was performed with UP-FUJI-MA80 machine manufactured by Shikoku Koki Co., Ltd., and the contents were filled with activated carbon filtered water as sensory evaluation water A brick type paper container having a volume of 250 ml was obtained.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container, and the results are shown in Table 2.
<Example 3 and Example 4>

As the resin A constituting the polyolefin film I layer, an ethylene-propylene random copolymer (2.7% by weight of a monomer unit based on ethylene, melting point 142 ° C., MFR 2.4 g / 1)
85% by weight of 0.1% by weight of benzylidene sorbitol derivative as a crystal nucleating agent at 0 minute), and ethylene-propylene random copolymer (ethylene-based monomer unit) as resin B constituting the polyolefin film I layer 0.4 wt%, melting point 156 ° C, MFR2
. 3 g / 10 min) was added 0.1% by weight of benzylidene sorbitol derivative as a crystal nucleating agent, and 15% by weight of resin A and resin B were mixed to prepare a resin constituting the polyolefin film I layer.

As resin C constituting the biaxially oriented oriented polyolefin film II layer, an ethylene-propylene random copolymer (ethylene monomer unit 0.4 wt%, melting point 156 ° C.,
Oriented polyolefin film II biaxially oriented with 75% by weight of MFR 2.3 g / 10 min)
The resin D constituting the layer was 25% by weight of propylene-1-butene copolymer (16.6% by weight of monomer unit based on 1-butene, melting point 110 ° C., MFR 6.0 g / 10 min), and resin C And resin D were mixed to prepare a biaxially oriented oriented polyolefin film II layer resin.

Coextruded using a multilayer die so that the biaxially oriented oriented polyolefin film II layer resin was laminated on both surfaces of the polyolefin film I layer resin to obtain an unstretched sheet. The sheet was stretched 7.0 times in MD, then 11 times in TD, heat treated for 15 seconds at the tenter heat treatment temperature shown in Table 1, and then subjected to corona discharge treatment on both sides to obtain a polyolefin film I layer. A biaxially oriented laminated polyolefin film for a liquid paper container having a thickness of 24 μm and a biaxially oriented oriented polyolefin film II layer laminated on both sides of 3.0 μm and a thickness of 3.0 μm was obtained. The physical properties of the biaxially stretched laminated polyolefin film for liquid paper containers are shown in Table 1. The biaxially stretched laminated polyolefin film for liquid paper containers treated at a tenter heat treatment temperature of 171 ° C. was used in Example 3, and the biaxially stretched laminated polyolefin film for liquid paper containers treated at a tenter heat treatment temperature of 173 ° C. was taken as an example. It was set to 4.
The biaxially stretched laminated polyolefin film for liquid paper container obtained had a wetting index of 41 mN / m on both sides in both Example 3 and Example 4.

Next, using a two-component curable ester adhesive on one side of the obtained biaxially stretched laminated polyolefin film for liquid paper containers, a thickness of 20 μm by a dry laminating method at a drying temperature of 70 ° C.
A low-density polyethylene film was laminated to obtain a multilayer film having a thickness of 52 μm. The wetting index on the biaxially oriented laminated polyolefin film side for liquid paper containers of laminated multilayer films is
Example 3 was reduced to 40 mN / m, and Example 4 was reduced to 39 mN / m.
Next, in both Example 3 and Example 4, a 7 μm thick aluminum foil was similarly used on the biaxially stretched laminated polyolefin film side for a liquid paper container of the multilayer film, and a drying temperature of 70 was used. Dry lamination was performed at 0 ° C. to obtain a laminate 1 having a thickness of 61 μm having a three-layer structure in which a low-density polyethylene film, a biaxially stretched laminated polyolefin film for liquid paper containers, and an aluminum foil are laminated in this order. The laminate 1 was cured for 3 days, and the laminate adhesive strength between the respective layers was measured.

The laminate adhesive strength between the low density polyethylene film of the laminate 1 of Example 3 and the biaxially stretched laminated polyolefin film for liquid paper containers was 4.09 N / 15 mm. on the other hand,
The laminate adhesive strength between the aluminum foil and the biaxially stretched laminated polyolefin film for liquid paper containers was 3.75 N / 15 mm.
The laminate adhesive strength between the low density polyethylene film of laminate 1 of Example 4 and the biaxially stretched laminated polyolefin film for liquid paper containers was 3.76 N / 15 mm. on the other hand,
The laminate adhesive strength between the layers of the aluminum foil and the biaxially oriented laminated polyolefin film for liquid paper containers was 2.88 N / 15 mm.

Next, a low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paper board having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.
Next, the printed product 1 is subjected to a punching process with a straw piercing port, and the aluminum foil side of the three-layer laminate 1 is laminated while extruding and laminating low-density polyethylene on the paper side of the printed matter 1. A laminate 2 was obtained in which printing, low density polyethylene, paper, low density polyethylene, aluminum foil, a biaxially stretched laminated polyolefin film for liquid paper containers, and a low density polyethylene film were laminated in this order. Furthermore, the low-density polyethylene is laminated on the printing surface of the laminate 2 while being extruded, and the low-density polyethylene (thickness 15 μm), printing, low-density polyethylene (thickness 15 μm), paper (basis weight 200 g / m ²⁾ Paperboard), low density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), biaxially stretched laminated polyolefin film for liquid paper containers (thickness 30 μm), and low density polyethylene film (thickness 20 μm) in this order. Obtained material.

The materials used at this time are as follows.
The low density polyethylene is Milason 16P manufactured by Mitsui Chemicals Co., Ltd., the low density polyethylene film is AJ-1 manufactured by Tamapoly Co., Ltd., and the paper has a basis weight of 200 g / m ² made from virgin pulp of softwood and hardwood. The paperboard and aluminum foil are JIS standard standard 1N30, and the biaxially stretched laminated polyolefin film for liquid paper containers is the biaxially stretched laminated polyolefin film for liquid paper containers of Example 3 or 4. After slitting the obtained liquid paper container material into a band with a predetermined width, the aseptic packaging was performed with UP-FUJI-MA80 machine manufactured by Shikoku Koki Co., Ltd., and the contents were filled with activated carbon filtered water as sensory evaluation water A brick type paper container having a volume of 250 ml was obtained.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container, and the results are shown in Table 2.
<Comparative Example 3>

A propylene homopolymer (melting point: 161 ° C., MFR: 2.5 g / 10 min) resin was extruded from a single-layer die to obtain an unstretched sheet. The sheet was stretched 4.5 times to MD, then 9 times to TD, heat treated for 15 seconds at the tenter heat treatment temperature shown in Table 1, and then subjected to corona discharge treatment on both sides. An axially stretched polyolefin film was obtained. The physical properties of the obtained biaxially stretched polyolefin film are shown in Table 1. The resulting biaxially oriented polyolefin film had a wetting index of 42 mN / m on both sides.

Using a two-component curable ester adhesive on one side of the obtained biaxially stretched polyolefin film, a low-density polyethylene film having a thickness of 20 μm is laminated by a dry laminating method at a drying temperature of 85 ° C. to obtain a multilayer film having a thickness of 42 μm. It was. The wetting index on the biaxially oriented polyolefin film side of the laminated multilayer film was 42 mN / m. Next, a 7 μm thick aluminum foil was dry laminated at a drying temperature of 85 ° C. on the biaxially oriented polyolefin film side of the multilayer film at the drying temperature of 85 ° C. A laminate 1 having a thickness of 49 μm having a three-layer structure in which an axially stretched polyolefin film and an aluminum foil are laminated in this order was obtained. The laminate 1 was cured for 3 days, and the laminate adhesive strength between the respective layers was measured.

The laminate adhesive strength between the layers of the low-density polyethylene film and the biaxially stretched polyolefin film of the laminate 1 was 4.95 N / 15 mm. On the other hand, the laminate adhesive strength between the aluminum foil and the biaxially stretched polyolefin film was 5.06 N / 15 mm. Then
A low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paperboard having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.
Next, the printed product 1 is subjected to a punching process with a straw piercing port, and the aluminum foil side of the three-layer laminate 1 is laminated while extruding and laminating low-density polyethylene on the paper side of the printed matter 1. Laminate 2 in which printing, low density polyethylene, paper, low density polyethylene, aluminum foil, biaxially oriented polyolefin film, and low density polyethylene film are laminated in this order
Got. Furthermore, it is laminated while extruding low density polyethylene on the printing surface of the laminate 2,
From the outermost layer side, low density polyethylene (thickness 15 μm), printing, low density polyethylene (thickness 1
5 μm), paper (paperboard with a basis weight of 200 g / m ² ), low density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), biaxially oriented polyolefin film (thickness 20 μm), and low density polyethylene film (thickness 20 μm) in this order. A laminated liquid paper container material was obtained.

The materials used at this time are as follows.
The low-density polyethylene is made of Mitsui Chemicals Co., Ltd. Mirason 16P, the low-density polyethylene film is Tamapoly Co., Ltd. AJ-1, and the paper is made of softwood and hardwood virgin pulp with a basis weight of 200 g / m ² . The paperboard and aluminum foil are JIS standard standard products 1N30, and the biaxially stretched polyolefin film is the biaxially stretched polyolefin film obtained in Comparative Example 3. After slitting the obtained liquid paper container material into a band with a predetermined width, the aseptic packaging was performed with UP-FUJI-MA80 machine manufactured by Shikoku Koki Co., Ltd., and the contents were filled with activated carbon filtered water as sensory evaluation water A brick type paper container having a volume of 250 ml was obtained.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container. The results are shown in Table 2.
<Example 5>

As the resin A constituting the polyolefin film I layer, an ethylene-propylene random copolymer (4.6% by weight of ethylene-based monomer unit, melting point 135 ° C., MFR 2.1 g / 1)
80% by weight of 0.1% by weight of benzylidene sorbitol derivative as a crystal nucleating agent at 0 minute), and ethylene-propylene random copolymer (ethylene-based monomer unit) as resin B constituting the polyolefin film I layer 0.4 wt%, melting point 156 ° C, MFR2
. 3 g / 10 min) was added 0.1% by weight of a benzylidene sorbitol derivative as a crystal nucleating agent to 20% by weight, and a resin A and a resin B were mixed to prepare a resin for a polyolefin film I layer.

As resin C constituting the biaxially oriented oriented polyolefin film II layer, an ethylene-propylene random copolymer (ethylene monomer unit 0.4 wt%, melting point 156 ° C.,
Oriented polyolefin film II biaxially oriented with 70% by weight of MFR 2.3 g / 10 min)
As resin D constituting the layer, ethylene-propylene-1-butene terpolymer (6.2% by weight of monomer units based on ethylene, 5.1% by weight of monomer units based on 1-butene, melting point 13
Resin C and Resin D were mixed at 0 ° C. and MFR 5.0 g / 10 min) to 30 wt% to prepare a biaxially oriented oriented polyolefin film II layer resin.

An unstretched sheet was obtained by co-extrusion using a multilayer die so that the resin of the oriented polyolefin film II layer biaxially oriented on both surfaces of the resin of the polyolefin film I layer was laminated. The sheet was stretched 5.8 times in MD, then 10 times in TD, heat treated at the tenter heat treatment temperature shown in Table 1 for 15 seconds, and then subjected to corona discharge treatment on both sides to obtain a polyolefin film I layer thickness. Is 31μm, biaxially oriented oriented polyolefin film II laminated on both sides II
A biaxially stretched laminated polyolefin film for a liquid paper container having a thickness of 4.5 μm and a thickness of 4.5 μm was obtained. The physical properties of the biaxially stretched laminated polyolefin film for liquid paper containers are shown in Table 1. The resulting biaxially oriented laminated polyolefin film for liquid paper containers has a wetting index of 42 mN on both sides.
/ M.

Next, using a two-component curable ester adhesive on one side of the obtained biaxially stretched laminated polyolefin film for liquid paper containers, a thickness of 15 μm by a dry laminating method at a drying temperature of 80 ° C.
Were laminated to obtain a multilayer film having a thickness of 57 μm. The wetting index on the side of the biaxially stretched laminated polyolefin film for liquid paper containers is 4
It was reduced to 0 mN / m. Next, the aluminum foil having a thickness of 7 μm is dry-laminated at a drying temperature of 80 ° C. using the same two-component curable ester adhesive on the biaxially stretched laminated polyolefin film side of the multilayer film for a liquid paper container. A thickness of 64 μm, laminated in the order of polyethylene film, biaxially oriented laminated polyolefin film for liquid paper containers, and aluminum foil
A laminate 1 having a three-layer structure was obtained. The laminate 1 was cured for 3 days, and the laminate adhesive strength between the respective layers was measured.

The laminate adhesive strength between the low density polyethylene film of laminate 1 and the biaxially oriented laminated polyolefin film for liquid paper containers was 3.09 N / 15 mm. On the other hand, the laminate adhesion strength between the aluminum foil and the biaxially oriented laminated polyolefin film for liquid paper containers is 2.7.
It was 4 N / 15 mm.
Next, a low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paper board having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.

Next, the printed product 1 is subjected to a punching process with a straw piercing port, and the aluminum foil side of the three-layer laminate 1 is laminated while extruding and laminating low-density polyethylene on the paper side of the printed matter 1. A laminate 2 was obtained in which printing, low density polyethylene, paper, low density polyethylene, aluminum foil, a biaxially stretched laminated polyolefin film for liquid paper containers, and a low density polyethylene film were laminated in this order. Furthermore, the low-density polyethylene is laminated on the printing surface of the laminate 2 while being extruded, and the low-density polyethylene (thickness 15 μm), printing, low-density polyethylene (thickness 15 μm), paper (basis weight 200 g / m ² ) from the outermost layer side. Paperboard), low density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), biaxially stretched laminated polyolefin film (thickness 40 μm) for liquid paper containers, and low density polyethylene film (thickness 15 μm) in this order. Obtained material.

The materials used at this time are as follows.
Low density polyethylene, both manufactured by Mitsui Chemicals, Inc. Mirason 16P, low density polyethylene film Tamapoly Co. AJ-1, paper basis weight is papermaking from virgin pulp softwood and hardwood is 200 g / m ² The paperboard and aluminum foil are JIS standard standard 1N30, and the biaxially stretched laminated polyolefin film for liquid paper containers is the biaxially stretched laminated polyolefin film for liquid paper containers obtained in Example 5. After slitting the obtained liquid paper container material into a band with a predetermined width, the aseptic packaging was performed with UP-FUJI-MA80 machine manufactured by Shikoku Koki Co., Ltd., and the contents were filled with activated carbon filtered water as sensory evaluation water A brick type paper container having a volume of 250 ml was obtained.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container. The results are shown in Table 2.
<Comparative example 4>

As the resin A constituting the polyolefin film I layer, an ethylene-propylene random copolymer (4.6% by weight of ethylene-based monomer unit, melting point 135 ° C., MFR 2.1 g / 1)
Resin constituting a polyolefin film I layer resin using 100% by weight of 0.1% by weight of benzylidene sorbitol derivative added as a crystal nucleating agent to 0 minute), and forming a biaxially oriented oriented polyolefin film II layer As C, ethylene-propylene random copolymer (ethylene monomer unit 0.4% by weight, melting point 156 ° C., MFR 2.3 g / 10
%) Was used to prepare a biaxially oriented oriented polyolefin film II layer resin.

An unstretched sheet was obtained by co-extrusion using a multilayer die so that the resin of the oriented polyolefin film II layer biaxially oriented on both surfaces of the resin of the polyolefin film I layer was laminated. The sheet was stretched 5.8 times in MD, then 10 times in TD, heat treated at the tenter heat treatment temperature shown in Table 1 for 15 seconds, and then subjected to corona discharge treatment on both sides to obtain a polyolefin film I layer. A biaxially oriented laminated polyolefin film for a liquid paper container having a thickness of 15.6 μm and a biaxially oriented oriented polyolefin film II layer laminated on both sides of 2.2 μm and a thickness of 20 μm was obtained. The resulting biaxially stretched laminated film had a wetting index of 42 mN / m on both sides. The physical properties of the biaxially stretched laminated polyolefin film for liquid paper containers are shown in Table 1.

A low-density polyethylene film having a thickness of 20 μm is laminated on one side of the obtained biaxially stretched laminated polyolefin film for a liquid paper container using a two-component curable ester adhesive at a drying temperature of 80 ° C. by a dry laminating method. A layer film was obtained. The wetting index of the multilayer film on the side of the biaxially stretched laminated polyolefin film for liquid paper containers was reduced to 35 mN / m. Next, an aluminum foil having a thickness of 7 μm is dry-laminated at a drying temperature of 80 ° C. using a two-component curable ester adhesive on the biaxially stretched laminated polyolefin film side of the multilayer film for liquid paper containers. A laminate 1 having a thickness of 51 μm and having a three-layer structure in which a film, a biaxially stretched laminated polyolefin film for liquid paper containers, and an aluminum foil are laminated in this order was obtained.
The laminate 1 was cured for 3 days, and the laminate adhesive strength between the respective layers was measured. The laminate adhesive strength between the low-density polyethylene film of laminate 1 and the biaxially stretched laminated polyolefin film for liquid paper containers was 3.12 N / 15 mm. On the other hand, the laminate adhesive strength between the layers of the aluminum foil and the biaxially stretched laminated polyolefin film for liquid paper containers was 0.49 N / 15 mm.

Next, a low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paper board having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.
Next, the printed product 1 is subjected to a punching process with a straw piercing port, and the aluminum foil side of the three-layer laminate 1 is laminated while extruding and laminating low-density polyethylene on the paper side of the printed matter 1. A laminate 2 was obtained in which printing, low density polyethylene, paper, low density polyethylene, aluminum foil, a biaxially stretched laminated polyolefin film for liquid paper containers, and a low density polyethylene film were laminated in this order. Furthermore, the low-density polyethylene is laminated on the printing surface of the laminate 2 while being extruded, and the low-density polyethylene (thickness 15 μm), printing, low-density polyethylene (thickness 15 μm), paper (basis weight 200 g / m ² ) from the outermost layer side. Paperboard), low-density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), biaxially stretched laminated polyolefin film (thickness 20 μm) for liquid paper containers, and low-density polyethylene film (thickness 20 μm). Obtained material.

The materials used at this time are as follows.
The low-density polyethylene is made of Mitsui Chemicals Co., Ltd. Mirason 16P, the low-density polyethylene film is Tamapoly Co., Ltd. AJ-1, and the paper is made of softwood and hardwood virgin pulp with a basis weight of 200 g / m ² . The paperboard and aluminum foil are JIS standard standard 1N30, and the biaxially stretched laminated polyolefin film for liquid paper containers is the biaxially stretched laminated polyolefin film for liquid paper containers obtained in Comparative Example 4. After slitting the obtained liquid paper container material into a band with a predetermined width, the aseptic packaging was performed with UP-FUJI-MA80 machine manufactured by Shikoku Koki Co., Ltd., and the contents were filled with activated carbon filtered water as sensory evaluation water A brick type paper container having a volume of 250 ml was obtained. However, during filling and packaging, the laminate part of the biaxially stretched laminated polyolefin film for liquid paper containers and the aluminum foil in most brick type paper container configurations peeled off, resulting in the biaxially stretched laminated polyolefin film for liquid paper containers and low density polyethylene film. The heat seal part of the laminate was torn and water leakage of the contents occurred.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container. The results are shown in Table 2.
<Example 6>

As the resin A constituting the polyolefin film I layer, an ethylene-propylene random copolymer (4.6% by weight of ethylene-based monomer unit, melting point 135 ° C., MFR 2.1 g / 1)
80% by weight of 0.1% by weight of benzylidene sorbitol derivative as a crystal nucleating agent at 0 minute), and ethylene-propylene random copolymer (ethylene-based monomer unit) as resin B constituting the polyolefin film I layer 0.4 wt%, melting point 156 ° C, MFR2
. 3 g / 10 min) was added 0.1% by weight of a benzylidene sorbitol derivative as a crystal nucleating agent to 20% by weight, and a resin A and a resin B were mixed to prepare a resin for a polyolefin film I layer.

As resin C constituting the biaxially oriented oriented polyolefin film II layer, an ethylene-propylene random copolymer (ethylene monomer unit 0.4 wt%, melting point 156 ° C.,
Oriented polyolefin film II biaxially oriented with 75% by weight of MFR 2.3 g / 10 min)
As resin D constituting the layer, ethylene-propylene-1-butene terpolymer (6.2% by weight of monomer units based on ethylene, 5.1% by weight of monomer units based on 1-butene, melting point 13
Resin C and Resin D were mixed at 0 ° C. and MFR 5.0 g / 10 min) to 25 wt% to prepare a biaxially oriented oriented polyolefin film II layer resin.

A non-stretched sheet was obtained by coextrusion using a multilayer die so that the biaxially oriented resin of the oriented polyolefin film II layer was laminated on one side of the resin of the polyolefin film I layer. The sheet was stretched 5.8 times in MD, then 10 times in TD, heat treated at the tenter heat treatment temperature shown in Table 1 for 15 seconds, and then subjected to corona discharge treatment on both sides to obtain a polyolefin film I layer. A biaxially oriented laminated polyolefin film for a liquid paper container having a thickness of 33 μm and a biaxially oriented oriented polyolefin film II layer laminated on one side and having a thickness of 7 μm was obtained.
The physical properties of the biaxially stretched laminated polyolefin film for liquid paper containers are shown in Table 1.

The resulting biaxially stretched laminated polyolefin film for liquid paper containers had a wetting index of 41 mN / m on the biaxially oriented oriented polyolefin film II layer side and 42 mN / m on the other polyolefin film I layer side.
Next, using the two-component curable ester adhesive on the polyolefin film I layer side of the obtained biaxially stretched laminated polyolefin film for liquid paper containers, a low density polyethylene film having a thickness of 15 μm by a dry laminating method at a drying temperature of 75 ° C. And a multilayer film having a thickness of 57 μm was obtained. The wetting index on the biaxially oriented oriented polyolefin film II layer side of the biaxially oriented laminated polyolefin film for liquid paper containers of the multilayer film was reduced to 39 mN / m.

Next, the aluminum foil having a thickness of 7 μm is dried using the same two-component curable ester adhesive on the biaxially oriented oriented polyolefin film II layer side of the biaxially oriented laminated polyolefin film for a liquid paper container of the multilayer film. Dry lamination was performed at a temperature of 75 ° C. to obtain a laminate 1 having a thickness of 64 μm having a three-layer structure in which a low-density polyethylene film, a biaxially stretched laminated polyolefin film for liquid paper containers, and an aluminum foil are laminated in this order.
The laminate 1 was cured for 3 days, and the laminate adhesive strength between the respective layers was measured.

The laminate adhesive strength between the low-density polyethylene film of laminate 1 and the polyolefin film I layer of the biaxially stretched laminated polyolefin film for liquid paper containers was 2.49 N / 15 mm. On the other hand, the laminate adhesive strength between the biaxially oriented polyolefin film II layers of the aluminum foil and the biaxially stretched laminated polyolefin film for liquid paper containers is 2.65 N / 15 mm.
Met.
Next, a low-density polyethylene having a thickness of 15 μm was melt-extruded and laminated on a paper board having a basis weight of 200 g / m ² , and printing was performed on the low-density polyethylene to obtain a printed matter 1.

Next, the printed product 1 is subjected to a punching process with a straw piercing port, and the aluminum foil side of the three-layer laminate 1 is laminated while extruding and laminating low-density polyethylene on the paper side of the printed matter 1. A laminate 2 was obtained in which printing, low density polyethylene, paper, low density polyethylene, aluminum foil, a biaxially stretched laminated polyolefin film for liquid paper containers, and a low density polyethylene film were laminated in this order. Furthermore, the low-density polyethylene is laminated on the printing surface of the laminate 2 while being extruded, and the low-density polyethylene (thickness 15 μm), printing, low-density polyethylene (thickness 15 μm), paper (basis weight 200 g / m ² ) from the outermost layer side. Paperboard), low density polyethylene (thickness 30 μm), aluminum foil (thickness 7 μm), biaxially stretched laminated polyolefin film (thickness 40 μm) for liquid paper containers, and low density polyethylene film (thickness 15 μm) in this order. Obtained material.

The materials used at this time are as follows.
Low density polyethylene, both manufactured by Mitsui Chemicals, Inc. Mirason 16P, low density polyethylene film Tamapoly Co. AJ-1, paper basis weight is papermaking from virgin pulp softwood and hardwood is 200 g / m ² The paperboard and aluminum foil are JIS standard standard 1N30, and the biaxially stretched laminated polyolefin film for liquid paper containers is the biaxially stretched laminated polyolefin film for liquid paper containers obtained in Example 6. After slitting the obtained liquid paper container material into a band with a predetermined width, the aseptic packaging was performed with UP-FUJI-MA80 machine manufactured by Shikoku Koki Co., Ltd., and the contents were filled with activated carbon filtered water as sensory evaluation water A brick type paper container having a volume of 250 ml was obtained.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container. The results are shown in Table 2.
<Example 7>

As sealant layer A, three layers were obtained by coextrusion, a) propylene-ethylene-1-
Thickness consisting of butene terpolymer (2.3% by weight of monomer units based on ethylene, 1.3% by weight of monomer units based on 1-butene, melting point 137 ° C., MFR 7.0 g / 10 min) 6μm
B) propylene-ethylene random copolymer (ethylene-based monomer unit 3.6)
Wt%, melting point 146 ° C., MFR 7.0 g / 10 min) 70 wt%, ethylene-1-butene copolymer (1-butene based monomer unit 15 wt%, melting point 69 ° C., MFR 6.7 g / 10)
Min) a layer having a thickness of 20 μm composed of a resin mixed with 30% by weight and c) an ethylene-1-butene copolymer (15% by weight of monomer unit based on 1-butene, melting point 69 ° C., MFR 6.7 g /
10 minutes), a layer having a thickness of 4 μm, and a layer having a total thickness of 30 μm.
The layer a non-stretched polyolefin film was subjected to corona discharge treatment on the surface of the a-layer of the three-layer unstretched polyolefin film, and the biaxially stretched laminated polyolefin film for a liquid paper container obtained in Example 1 was applied to the corona discharge treated surface. A multilayer film having a thickness of 52 μm was obtained by the dry lamination method in the same manner as in Example 1 except that the lamination was performed. The wetting index of the laminated multilayer film on the side of the biaxially stretched laminated polyolefin film for liquid paper containers was reduced to 39 mN / m.

Further, using the obtained multilayer film, in the same manner as in Example 1, the laminate 1 (three-layer unstretched polyolefin film / biaxially stretched laminated polyolefin film for liquid paper container / aluminum foil was laminated in this order, thickness 61 μm) ), Printed material 1, laminate 2 (printing / low density polyethylene / paper /
Low density polyethylene / aluminum foil / biaxially stretched polyolefin film for liquid paper containers / 3
Layered non-stretched polyolefin film in order), liquid paper container material (from outermost layer side, low density polyethylene (thickness 15 μm) / printing / low density polyethylene (thickness 15 μm) / paper (paperboard with basis weight 200 g / m ² ) / Low density polyethylene (thickness 30 μm) / aluminum foil (thickness 7 μm)
) / Biaxially stretched laminated polyolefin film for liquid paper containers (thickness 20 μm) / 3-layer unstretched polyolefin film (thickness 30 μm).

The laminate adhesion strength between the three-layer unstretched polyolefin film and the biaxially stretched laminated polyolefin film for liquid paper container of the laminate 1 after curing for 3 days is 4.61 N / 15 mm.
Met. On the other hand, the laminate adhesive strength between the aluminum foil and the biaxially stretched laminated polyolefin film for liquid paper containers was 3.39 N / 15 mm.
After slitting the obtained liquid paper container material into a belt with a predetermined width, U made by Shikoku Koki Co., Ltd.
Aseptic packaging was performed with a P-FUJI-MA80 machine, and a brick-type paper container having an internal volume of 250 ml was obtained by adding activated carbon filtered water as sensory evaluation water to the contents.
The resulting brick-type paper container was subjected to buckling strength, straw piercing evaluation and resin odor evaluation of the paper container. The results are shown in Table 2.

It is a perspective view of the brick type liquid paper container of the present invention. It is the peak-separation result of the X-ray-diffraction curve of the biaxially stretched laminated polyolefin film for liquid paper containers of Example 1 of this invention. It is a layer block diagram of the liquid paper container material containing the straw stab hole of Examples 1, 2, 3, 4, 5 and Comparative Examples 1 and 4. FIG. It is a layer block diagram of the liquid paper container material containing the straw stab hole of Example 6. FIG. It is a layer block diagram of the liquid paper container material containing the straw stab hole of the comparative example 2. It is a layer block diagram of the liquid paper container material containing the straw stab hole of the comparative example 3. It is a layer block diagram of the liquid paper container material containing the straw stab hole of Example 7. FIG.

Explanation of symbols

1: Extruded LDPE layer
2: Print layer
3: Paper layer
4: Aluminum foil layer
5: Oriented polyolefin film II layer
6: Polyolefin film I layer
7: LDPE film layer
8: Biaxially stretched polyolefin film layer
9: 3-layer unstretched polyolefin film layer
10: Straw piercing hole

Claims (5)

A biaxially oriented laminated polyolefin film having a plane orientation index of 0.6 or less, wherein a biaxially oriented oriented polyolefin film II layer is laminated on at least one side of the polyolefin film I layer,
(1) Polyolefin 75-1 whose polyolefin film I layer has a melting point of 130-145 ° C.
00% by weight, and a polyolefin having a melting point of 154-164 ° C., 0-25% by weight,
(2) Polyolefin 20 to 5 having biaxially oriented oriented polyolefin film II layer having a melting point of 154 to 164 ° C. and a melting point of 105 to 145 ° C.
A biaxially stretched laminated polyolefin film for liquid paper containers, comprising 0% by weight. MD, TD elastic modulus is in the range of 1200 to 2200 MPa, film piercing strength is 2
2. The biaxially stretched laminated polyolefin film for liquid paper containers according to claim 1, wherein the elongation rate until the needle penetrates the film in the measurement of piercing strength of the film is 4% or less. When laminating is performed on both sides of the film, the laminating adhesive strength on both sides is 1.5.
3. The biaxially stretched laminated polyolefin film for liquid paper containers according to claim 2, wherein the thickness is N / 15 mm or more. The layers are laminated in the order of at least the sealant B layer, the printing layer, the paper layer, the aluminum foil layer, the biaxially stretched laminated polyolefin film layer for liquid paper containers, and the sealant A layer from the outermost layer side. Liquid paper container material. A liquid paper container, wherein the liquid paper container material is aseptically packaged with the liquid paper container material according to claim 4.

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