JP2019025714A - Multilayer film, package, and manufacturing method of multilayer film - Google Patents

Abstract

To provide a multilayer film having more excellent impact resistance and more excellent easy opening property, a package, and a manufacturing method of the multilayer film.SOLUTION: There is provided a multilayer film 10 having an outermost layer 1 and an innermost layer 2, in which the outermost layer 1 contains at least one kind selected from polyethylene terephthalate, polybutylene terephthalate, and glycyl modified polyethylene terephthalate, the innermost layer 2 contains polyolefin, the outermost layer 1 has orientation degree α1 in an MD direction measured by an infrared dichroic method of 0.2 to 2.5, and orientation degree β1 in a TD direction measured by the infrared dichroic method of 0.2 to 2.5, the innermost layer 2 has orientation degree α2 in the MD direction measured by the infrared dichroic method of 0.2 to 2.5, and orientation degree β2 in the TD direction measured by the infrared dichroic method of 0.2 to 2.5, and a ratio of peak area S1 of the melting point of smectic crystals and peak area S2 of the melting point of single crystals, S1/S2 of 1/99 to 10/90.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multilayer film, a package, and a method for producing the multilayer film.

  For example, a multilayer film including a plastic film is frequently used for packaging bodies such as pharmaceuticals and foods. The package is required to have physical properties such as not being easily broken by a shock caused by vibration or dropping during distribution (high impact resistance) and easily opened by hand (high easy opening).

  Patent Document 1 discloses a package in which the outermost layer is a biaxially stretched polyester and the orientation coefficient of the outermost layer is in a specific range. According to this invention, the easy-openability is improved.

Japanese Patent No. 2576747

However, the packaging body made of plastic film is required to have better impact resistance and better openability.
In order to increase the impact resistance of the invention of Patent Document 1, if the strength of the outermost film is simply increased, the easy-openability is impaired.
This invention is made | formed in view of the said situation, and aims at the manufacturing method of a multilayer film provided with the more outstanding impact resistance and the more easily openability, and a multilayer body, and a multilayer film.

It is known that the plastic crystal structure includes an α crystal (also referred to as a monoclinic crystal), a β crystal (also referred to as a hexagonal crystal), and a γ crystal (also referred to as a triclinic crystal).
The inventors of the present invention, by subjecting a plastic blended with a polymer having a molecular structure similar to a part of the molecular structure of the matrix polymer to a heat treatment under predetermined conditions, lowers the melting point of the β crystal by 10 ° C. or more. It was found that crystals having an endothermic peak were formed. This crystal is called β ′ crystal (β prime crystal, also called pseudo-hexagonal crystal or smectic crystal), and is considered to be a crystal at the previous stage where β crystal is generated. The β ′ crystal has a smaller crystallinity than the β crystal and is considered to improve the impact resistance of the plastic. In addition, it is considered that the β ′ crystal has a function of promoting the plane orientation of the plastic and promoting the easy-openability.
As a result of intensive studies, the present inventors have been able to achieve both impact resistance and easy-openability by adding a blend polymer having a similar molecular structure to a matrix polymer that is a copolymer and then performing a heat treatment. The present inventors have found that the above problems can be solved.
That is, this invention has the following aspects.
[1] having an outermost layer and an innermost layer;
The outermost layer includes at least one selected from polyethylene terephthalate, polybutylene terephthalate and glycol-modified polyethylene terephthalate,
The innermost layer comprises a polyolefin;
The outermost layer has an MD orientation degree α1 of 0.2 to 2.5 measured by infrared dichroism, and a TD orientation degree β1 of 0.2 to 2 measured by infrared dichroism. .5,
The innermost layer has an MD orientation degree α2 of 0.2 to 2.5 measured by infrared dichroism, and a TD orientation degree β2 of 0.2 to 2 measured by infrared dichroism. .5,
A multilayer film having a ratio S1 / S2 of 1/99 to 10/90 of the peak area S1 of the melting point of smectic crystal and the peak area S2 of the melting point of monoclinic crystal measured by a heat flux differential scanning calorimeter .
[2] The multilayer film according to [1], including an intermediate layer between the outermost layer and the innermost layer, wherein the intermediate layer includes at least one selected from polyamide, polyvinyl alcohol, and aluminum.
[3] The ratio represented by the degree of orientation α1 / the degree of orientation β1 is 0.5 to 2.0, and the ratio represented by the degree of orientation α2 / the degree of orientation β2 is 0.5 to 2.0. The multilayer film according to [1] or [2].
[4] A package in which the multilayer film according to any one of [1] to [3] is used, wherein the innermost layer forms an inner surface and the outermost layer forms an outer surface.

[5] A method for producing a multilayer film according to any one of [1] to [3], wherein one of outer layer materials including at least one selected from polyethylene terephthalate, polybutylene terephthalate, and glycol-modified polyethylene terephthalate The manufacturing method of the multilayer film which has the process of providing the inner-layer material containing polyolefin on a surface, and obtaining the laminated body, and the process of heat-processing the said laminated body.

  According to the multilayer film of the present invention, it is excellent in impact resistance and easy opening.

It is sectional drawing of the multilayer film concerning 1st embodiment of this invention. It is sectional drawing of the multilayer film concerning 2nd embodiment of this invention. It is an example of the DSC curve of the multilayer film of this invention.

  The multilayer film of the present invention includes an outermost layer and an innermost layer. Hereinafter, the multilayer film of the present invention will be described with reference to embodiments.

[First embodiment]
≪Multilayer film≫
As shown in FIG. 1, the multilayer film 10 of the first embodiment of the present invention has an outermost layer 1 and an innermost layer 2 provided on one surface of the outermost layer 1. The outermost layer 1 and the innermost layer 2 are joined via the first adhesive layer 4.

<Outermost layer>
The outermost layer 1 is selected from polyethylene terephthalate (hereinafter also referred to as “PET”), polybutylene terephthalate (hereinafter also referred to as “PBT”), and glycol-modified polyethylene terephthalate (hereinafter also referred to as “PETG”). Contains at least one.
The outermost layer 1 is preferably PET alone or a mixture of PBT and PETG.
The outermost layer 1 includes a matrix polymer (hereinafter also referred to as a main polymer) that is a copolymer, and a blend polymer (hereinafter also referred to as a secondary polymer) having a molecular structure similar to a part of the molecular structure of the matrix polymer. It is preferable to contain.
When the outermost layer 1 contains PBT and PETG, PBT is the main polymer and PETG is the subpolymer. PET is the main polymer.

When the outermost layer 1 contains PBT and PETG, the mass ratio represented by polybutylene terephthalate / glycol-modified polyethylene terephthalate in the outermost layer 1 (hereinafter also referred to as “PBT / PETG ratio”) is 99/1. -50/50 is preferable, and 95 / 5-70 / 30 is more preferable.
When the PBT / PETG ratio is within the above range, smectic crystals are easily generated in the multilayer film 10, and both easy opening and impact resistance are easily achieved.
The molecular structure of PETG, which is a secondary polymer, is similar to part of the molecular structure of PBT, which is the main polymer. Thus, it is considered that smectic crystals are easily generated in the multilayer film 10 by containing a predetermined amount of a subpolymer having a molecular structure similar to a part of the molecular structure of the main polymer.

60-100 mass% is preferable with respect to the gross mass of the outermost layer 1, and, as for content of PET, 70-100 mass% is more preferable. By setting the content of PET within the above numerical range, the easy-openability can be improved more easily.
The content of PBT is preferably 50 to 95% by mass and more preferably 60 to 90% by mass with respect to the total mass of the outermost layer 1. By making the content of PBT within the above numerical range, the impact resistance derived from PBT can be maintained.
3-60 mass% is preferable with respect to the total mass of the outermost layer 1, and, as for content of PETG, 5-50 mass% is more preferable. By setting the content of PETG within the above numerical range, the easy-openability can be improved more easily.
67-100 mass% is preferable with respect to the total mass of the outermost layer 1, and, as for the sum total of content of PET, content of PBT, and content of PETG, 80-100 mass% is more preferable. By making the total amount within the above numerical range, the impact resistance and the easy-opening property are improved.

The outermost layer 1 may contain other resins of PET, PBT, and PETG. Examples of other resins include polytrimethylene terephthalate (PTT) and polyethylene naphthalate (PEN).
The content of other resins is preferably 0 to 33% by mass, and more preferably 0 to 20% by mass. When the content of the other resin is within the above numerical range, the impact resistance and the easy-openability are good.

The degree of orientation α1 in the MD direction (flow direction and length direction when producing a multilayer film) in the outermost layer 1 is 0.2 to 2.5, preferably 0.5 to 2.0, 0.5 to 1.5 is more preferable. If it is more than the said lower limit, easily openability will be acquired. If it is below the said upper limit, impact resistance can be improved.
The degree of orientation β1 in the TD direction (direction perpendicular to the MD direction, width direction) in the outermost layer 1 is 0.2 to 2.5, preferably 0.5 to 2.0, and preferably 0.5 to 1.5. Is more preferable. If it is more than the said lower limit, easily openability will be acquired. If it is below the said upper limit, impact resistance can be improved.

  The ratio represented by the orientation degree α1 / orientation degree β1 (hereinafter sometimes referred to as α1 / β1 ratio) is preferably 0.5 to 2.0, and more preferably 0.5 to 1.5. By setting the α1 / β1 ratio within the above numerical range, it becomes easy to improve easy-openability in both the MD direction and the TD direction.

The orientation degree α1 and the orientation degree β1 are calculated from values measured by the infrared dichroism method.
The degree of orientation is measured by a transmission method using light called linearly polarized light in which the electric field of light vibrates only in a certain direction in an infrared spectrophotometer.
As a measuring method, first, BKG (background) measurement is performed with the polarizer installation angle set to 0 ° (electric field direction is vertical), and then the absorbance is measured by aligning the stretching direction of the sample with the vertical direction ( At this time, the direction of polarization and the direction of the stretching axis are parallel.) The obtained value is defined as absorbance “A //”.
Next, the sample is rotated at an angle of 90 °, and the absorbance is measured with the stretching axis of the sample and the polarization direction perpendicular to each other. The obtained value is defined as absorbance “A⊥”.
The degree of orientation is defined as the ratio of the two absorbances A // and A⊥ obtained with polarized light parallel to and perpendicular to the stretching axis of the sample.
The wave number measured in the infrared dichroism method is appropriately selected according to the material to be measured (“Koji Kobayashi,“ Molecular orientation by infrared dichroism ”, Journal of Polymer Science,“ Polymer ”, Vol. 15, No. 175, p.877-883 ”).
Further, the degree of orientation can be easily obtained from the tensile modulus measured according to JIS K7127 (1999).

6-15 micrometers is preferable and, as for the thickness of the outermost layer 1, 8-13 micrometers is more preferable. When the thickness of the outermost layer 1 is not less than the above lower limit value, the oxygen barrier property, the fragrance retention property, the pinhole resistance, and the impact resistance are easily improved. When the thickness of the outermost layer 1 is not more than the above upper limit value, the easy-opening property can be improved more easily.
The thickness of the outermost layer 1 can be measured with a thickness gauge.

<Inner layer>
The innermost layer 2 is a sealant layer that can be heat sealed with the innermost layers facing each other.
The innermost layer 2 contains a polyolefin. Examples of the resin constituting the innermost layer 2 include polyolefins such as low density polyethylene (LDPE), linear LDPE (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and polypropylene (PP), ethylene- Vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate copolymer ( EEA), ethylene-propylene rubber (EP-R), ionomer and the like. These resins may be used alone or in combination of two or more.
In addition, the innermost layer 2 may have a single layer structure or a multilayer structure.

When the outermost layer 1 is 100% by mass of PET, the innermost layer 2 is preferably a mixed polymer containing two or more kinds of polyolefins. 99 / 1-50 / 50 is preferable and, as for the mass ratio (main polymer / subpolymer) of the main polymer of a mixed polymer and a subpolymer, 95 / 5-70 / 30 is more preferable. Examples of the main polymer of the mixed polymer include PP. Examples of the subpolymer of the mixed polymer include LLDPE and EP-R.
When the mass ratio of the main polymer and the subpolymer of the mixed polymer is within the above range, smectic crystals are easily generated, and both easy opening and impact resistance are easily achieved.
The molecular structure of LLDPE, a secondary polymer, is similar to part of the molecular structure of PP, the main polymer. Alternatively, the molecular structure of the secondary polymer EP-R is similar to a part of the molecular structure of the main polymer PP. Thus, it is considered that smectic crystals are easily generated in the multilayer film 10 by containing a predetermined amount of a subpolymer having a molecular structure similar to a part of the molecular structure of the main polymer.

  50-100 mass% is preferable with respect to the total mass of the innermost layer 2, and, as for content of polyolefin, 80-100 mass% is more preferable. By setting it within the above numerical range, the sealing property when the package is formed is improved.

The MD degree of orientation α2 in the innermost layer 2 is 0.2 to 2.5, preferably 0.5 to 2.0, and more preferably 0.5 to 1.5. If it is more than the said lower limit, easily openability will be acquired. If it is below the said upper limit, impact resistance can be improved.
The degree of orientation β2 in the TD direction in the innermost layer 2 is 0.2 to 2.5, preferably 0.5 to 2.0, and more preferably 0.5 to 1.5. If it is more than the said lower limit, easily openability will be acquired. If it is below the said upper limit, impact resistance can be improved.

The ratio represented by the orientation degree α2 / orientation degree β2 (hereinafter sometimes referred to as α2 / β2 ratio) is preferably 0.5 to 2.0, and more preferably 0.5 to 1.5. By setting the α2 / β2 ratio within the above numerical range, it becomes easy to improve easy-openability in both the MD direction and the TD direction.
The orientation degree α2 and the orientation degree β2 are calculated from the values measured by the infrared dichroism method, similarly to the orientation degree α1 and the orientation degree β1.

The absolute value of the difference between the α1 / β1 ratio and the α2 / β2 ratio is preferably 0 to 0.5, and more preferably 0 to 0.2. By making the absolute value of the difference between the α1 / β1 ratio and the α2 / β2 ratio within the above numerical range, it becomes easy to improve easy-openability in both the MD direction and the TD direction.
The MD direction of the innermost layer 2 and the MD direction of the outermost layer 1 are preferably the same direction. When the MD direction of the innermost layer 2 and the MD direction of the outermost layer 1 are the same direction, easy-openability is easily improved.

  The thickness of the innermost layer 2 is preferably 20 to 100 μm, more preferably 25 to 80 μm, and further preferably 30 to 60 μm. When the thickness of the innermost layer 2 is within the above numerical range, easy opening and impact resistance can be easily improved.

  When the calorific value of the multilayer film 10 of the present embodiment is measured with a heat flux differential scanning calorimeter (hereinafter also referred to as DSC apparatus), an endothermic peak of the melting point of the smectic crystal of the multilayer film 10 is observed. The melting point of smectic crystals is lower than the melting point of monoclinic crystals. Since the smectic crystal is more unstable than the monoclinic crystal, the abundance ratio is smaller than that of the monoclinic crystal. Therefore, the endothermic peak of the smectic crystal observed by the DSC apparatus is smaller than the endothermic peak of the monoclinic crystal and appears on the low temperature side.

FIG. 3 shows a DSC curve when the multilayer film 10 is measured with a DSC apparatus. In FIG. 3, a curve 101 is a DSC curve of the multilayer film 10 before the heat treatment. A curve 201 is a DSC curve of the multilayer film 10 after the heat treatment.
In the curve 101, a large endothermic peak having a peak at 121.12 ° C. is observed. In the curve 201, a large endothermic peak having a peak at 121.81 ° C. is observed. These are endothermic peaks of the monoclinic melting point of polyethylene contained in the multilayer film 10.
The curve 101 shows no other endothermic peak, but the curve 201 shows a small endothermic peak with a peak at 110.03 ° C. This small endothermic peak is a smectic crystal endothermic peak of the multilayer film 10.

  The peak area of the endothermic peak of the melting point of the smectic crystal of the multilayer film 10 measured by the DSC apparatus is S1, and the peak area of the endothermic peak of the monoclinic melting point of the multilayer film 10 is S2. The ratio S1 / S2 between S1 and S2 is 1/99 to 10/90, preferably 2/98 to 8/92, and more preferably 3/97 to 6/94. When S1 / S2 is within the above range, both easy opening and impact resistance can be easily achieved.

  The peak area S1 of the endothermic peak of the melting point of the smectic crystal of the multilayer film 10 and the peak area S2 of the endothermic peak of the melting point of the hexagonal crystal of the multilayer film 10 can be calculated by the peak area calculation software in the DSC apparatus.

<First adhesive layer>
Examples of the material constituting the first adhesive layer 4 include adhesives such as polyester, epoxy, polyvinyl acetate, and acid-modified polyolefin, anchors such as titanate, polyurethane, polyethyleneimine, and polybutadiene. A coating agent is mentioned. Of these, modified polyethylene obtained by introducing a polar group into polyethylene is preferable. These materials may be used alone or in combination of two or more.
The thickness of the first adhesive layer 4 is preferably 3 to 10 μm. By making the thickness of the 1st contact bonding layer 4 into the said numerical range, interlayer adhesiveness becomes favorable and it becomes easy to express easily openability.

≪Method for producing multilayer film≫
The manufacturing method of the multilayer film 10 in this embodiment has the process (lamination process) of obtaining a laminated body provided with an outer layer material and an inner layer material, and the process (heating process) which heat-processes a laminated body.
The laminating step is a step of providing an inner layer material on one surface of the outer layer material.
The material of the outer layer material is the same as the material of the outermost layer. The material of the inner layer material is the same as the material of the innermost layer.
Examples of the method of providing the inner layer material on one surface of the outer layer material include an inflation method such as a water-cooled inflation method and an air-cooled inflation method, and a co-extrusion method such as a T-die method. Of these, the water-cooled inflation method is preferred because transparency and easy opening are easily improved. In addition, the multilayer film manufactured by the inflation method is called an inflation film.
In the inflation method, the blow ratio (stretch ratio in the TD direction) is preferably 0.7 to 3.0, and more preferably 0.7 to 2.0. By setting the blow ratio within the above numerical range, easy-openability is easily improved.

A heating process heat-processes a laminated body and accelerates | stimulates the production | generation of a smectic crystal.
By subjecting the laminate to heat treatment, the outer layer material becomes the outermost layer, and the inner layer material becomes the innermost layer.
80-135 degreeC is preferable and the temperature of heat processing has more preferable 90-125 degreeC. When the temperature of the heat treatment is within the above range, hexagonal crystals and smectic crystals are likely to be generated.
5-60 minutes are preferable, as for the time of heat processing, 10-50 minutes are more preferable, and 20-40 minutes are further more preferable. When the heat treatment time is equal to or more than the above lower limit value, the formation of smectic crystals is promoted. When the heat treatment time is not more than the above lower limit value, it is easy to suppress the growth from smectic crystals to monoclinic crystals.

≪Packaging body≫
The package of this embodiment is characterized in that the multilayer film 10 in this embodiment is used, the innermost layer 2 forms the inner surface, and the outermost layer 1 forms the outer surface. It is preferable that the MD direction is the length direction and the TD direction is the width direction.
Examples of the package include a bag formed by heat-sealing innermost layers of the multilayer film 10. Examples of the form of the package include a palm-attached bag, a three-side seal bag, a four-side seal bag, a gusset bag, a stand bag, and a bag with these chucks.
The package in the first embodiment of the present invention is suitable for use in packaging beverages, foods, pharmaceuticals, cosmetics and the like. Especially, it is suitable for uses, such as food for persons with difficulty in swallowing and chewing, such as a meal for a meal, a mixer meal, and a medical infusion bag.

≪Packaging manufacturing method≫
The multilayer film used for the package of the present embodiment can be manufactured in the same manner as the method for manufacturing the multilayer film 10. Of these, the water-cooled inflation method is preferred because transparency and easy opening are easily improved.
The obtained multilayer film remains in a cylindrical shape, and the upper end and the lower end may be heat-sealed to form a package, and after cutting a part of the cylindrical multilayer film into a sheet shape, the upper end, the lower end, and the side It is good also as a package by heat-sealing a part. When heat sealing, the innermost layer should be inside.

[Second Embodiment]
≪Multilayer film≫
As shown in FIG. 2, the multilayer film 20 in the second embodiment of the present invention includes an intermediate layer 3 between the outermost layer 1 and the innermost layer 2 provided on one surface of the outermost layer 1. . The outermost layer 1 and the intermediate layer 3 are joined via a second adhesive layer 5. The innermost layer 2 and the intermediate layer 3 are joined via a third adhesive layer 6. By having the intermediate layer 3, the impact resistance and oxygen barrier property can be further improved.
The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

<Intermediate layer>
The intermediate layer 3 preferably includes at least one selected from resin layers such as polyamide and polyvinyl alcohol and metal layers such as aluminum foil. Examples of the polyamide include nylon (for example, nylon 6, nylon 6-6, etc.). Examples of polyvinyl alcohol include an ethylene-vinyl alcohol copolymer. Examples of the metal layer include aluminum foil and copper foil.
When the mid layer 3 contains polyamide, the content of the polyamide is preferably 50 to 100% by mass and more preferably 70 to 100% by mass with respect to the total mass of the mid layer 3. By setting the polyamide content within the above numerical range, it is possible to further improve the impact resistance and the oxygen barrier property.
The thickness of the intermediate layer 3 is preferably 5 to 15 μm, more preferably 8 to 13 μm.

<Second adhesive layer>
Examples of the material constituting the second adhesive layer 5 include the same materials as those of the first adhesive layer 4.
The thickness of the second adhesive layer 5 is preferably 3 to 10 μm. By setting the thickness of the second adhesive layer 5 within the above numerical range, the interlaminar adhesiveness is improved and the easy-openability is easily exhibited.

<Third adhesive layer>
Examples of the material constituting the third adhesive layer 6 include the same materials as the first adhesive layer 4.
The thickness of the third adhesive layer 6 is preferably 3 to 10 μm. By setting the thickness of the third adhesive layer 6 within the above numerical range, the interlayer adhesiveness is improved and the easy-opening property is easily developed.

≪Method for producing multilayer film≫
The manufacturing method of the multilayer film 20 in the present embodiment includes a step of obtaining a laminate including an outer layer material, an intermediate material, and an inner layer material (lamination step), and a step of performing a heat treatment on the laminate (heating step).
A lamination process is a process of obtaining the laminated body in which the outer layer material, the intermediate material, and the inner layer material were provided in this order.
The material of the intermediate material is the same as the material of the intermediate layer.
The method of obtaining a laminate in which the outer layer material, the intermediate material, and the inner layer material are provided in this order is the same as the method of providing the inner layer material on one surface of the outer layer material.
The heating process of this embodiment is the same as the heating process of 1st embodiment of this invention.
By subjecting the laminate to heat treatment, the intermediate material becomes an intermediate layer.

≪Packaging body≫
The package of this embodiment is the same as that of the first embodiment except that the multilayer film 20 is used instead of the multilayer film 10 of the first embodiment.

≪Packaging manufacturing method≫
The method for manufacturing a package according to the second embodiment of the present invention is the same as the method for manufacturing a package according to the first embodiment of the present invention, except that the multilayer film 20 according to the second embodiment of the present invention is used. A similar method can be mentioned.

(Other embodiments)
The present invention is not limited to the above-described embodiment.
In 1st embodiment, although it has a 1st contact bonding layer, this invention is not limited to this, When the outermost layer and the innermost layer can be joined, the 1st contact bonding layer does not need to be.

In 2nd embodiment, although it has a 2nd contact bonding layer, this invention is not limited to this, When an outermost layer and an intermediate | middle layer can adhere | attach, a 2nd contact bonding layer does not need.
In 2nd embodiment, although it has a 3rd contact bonding layer, this invention is not limited to this, When an innermost layer and an intermediate | middle layer can adhere | attach, a 3rd contact bonding layer does not need.

  The multilayer film of the present invention may be printed on the outermost layer.

  The multilayer film of the present invention may be used as a lid material that closes the opening of the container.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
The composition of the resin in each example is shown in Table 1.
The raw materials used in this example are as follows.

≪Raw materials used≫
<Outermost layer>
PBT: Mitsubishi Engineering Plastics, trade name Nova Duran (registered trademark).
PETG: Eastman Chemical Company, trade name Eastar (registered trademark).
PET: DuPont, trade name Rynite (registered trademark).
<Second adhesive layer>
-Modified polyethylene (AD), Mitsubishi Chemical Corporation, trade name Modic (registered trademark).
<Intermediate layer>
Nylon-6: DSM, trade name Novamid (registered trademark).
Aluminum: UACJ foil company, aluminum foil.
Polyvinyl alcohol: Kuraray, EVOH.
<Third adhesive layer>
-Modified polyethylene (AD), Mitsubishi Chemical Corporation, trade name Modic (registered trademark).
<Inner layer>
LLDPE: Prime Polymer Co., Ltd., trade name Evolue (registered trademark).
PP: Prime Polymer, polypropylene.
EP-R: Mitsui Chemicals, trade name Toughmer (registered trademark).
-Nylon: Toray Industries, trade name Amilan (registered trademark).

[Examples 1-9, Comparative Examples 1-8]
A multilayer film having a width of 20 cm and a length of 100 m was obtained by water-cooled inflation molding using a circular die so as to satisfy the specifications of the multilayer film shown in Table 1. The multilayer film was formed in a cylindrical shape so that the innermost layer was located on the innermost side.
In Examples 6 to 8 and Comparative Examples 7 and 8, since the intermediate layer is made of an aluminum foil, after the innermost layer is formed by water-cooled inflation in advance, the outermost layer and the inner layer are formed on the aluminum foil by dry lamination. They were pasted together.
In the case of water-cooled inflation molding, the blow ratio was set to 0.7 in Examples 1-3, 5-9, and Comparative Examples 1-8, and the blow ratio was set to 1.5 in Example 4.
About the obtained multilayer film, easy-opening property, impact resistance, pinhole resistance, oxygen permeability, and aroma retention were evaluated as follows. The results are shown in Table 2.

<Easy opening>
The cylindrical multilayer film was torn by hand in the TD direction, and the multilayer film after tearing was observed. When it is possible to tear smoothly and linearly to the end, and when the difference in the distance between the front and back surfaces is 7 mm or less, “○” is indicated. Alternatively, the case where the distance difference between the front and back surface cuts was more than 7 mm was designated as “Δ”, and the case where the tearing could not be completed was designated as “x”.

<Impact resistance>
Impact resistance was evaluated according to JIS K7124-1. Among the 30 samples, “◯” indicates that the number of broken bags is 1 or less, “Δ” indicates that the number of broken bags is 2 to 3, and “x” indicates that the number of broken bags is 4 or more.

<Pinhole resistance>
If pinhole resistance is excellent, pinholes can be prevented from being generated due to friction and bending during transportation and storage.
The multilayer film was bent 500 times using a gel flex tester, and the number of pinholes generated was confirmed. The case where the occurrence of pinholes was 2 or less was designated as “◯”, the case where 3 to 5 places were “Δ”, and the case where there were 6 or more places was designated as “X”.

<Oxygen permeability>
If the oxygen permeability is low, the oxygen barrier property is excellent, and deterioration of the contents due to oxygen can be prevented.
The oxygen permeability was determined according to the JIS K7126-2 mocon method. Oxygen permeability "○" to 130 cc / ^{m 2} or less, a 130 cc / ^{m 2} Ultra 200 cc / ^m less than ² "△", and 200 cc / ^{m 2} or more as "×".

<Incense retention>
If the fragrance is excellent, the odor of the contents does not leak to the outside, which is preferable.
The multilayer film was cut to a length of 30 cm and the lower end was heat sealed, and then 100 g of coffee beans were charged, and the upper end of the multilayer film was heat sealed. The odor of this package was checked and the aroma retention was evaluated. The case where the odor component of the contents was not felt at all was indicated by “◯”, the case where the odor components of the contents were hardly felt was indicated by “Δ”, and the case where the odor components of the contents were slightly felt was indicated by “X”.

  In the above evaluation, if there is at least one item “x”, the overall evaluation is “x”. When the number of “◯” was 1 to 2, the overall evaluation was “Δ”, the number of “○” was 3 or more, and the overall evaluation was “◯”.

From the results of Table 1, Examples 1 to 9 to which the present invention was applied were all excellent in easy-openability, impact resistance, pinhole resistance, oxygen barrier properties and fragrance retention.
The comparative example 1 which did not blend PETG with PBT was inferior in easy-opening property, impact resistance, and pinhole resistance. Comparative Examples 2, 7, and 8 in which PET was used for the outermost layer and no blend polymer was used for the innermost layer were inferior in easy-openability, impact resistance, and pinhole resistance. In Comparative Example 3 in which the PBT / PETG ratio was 97/3 and the production ratio of smectic crystals was outside the range of the present invention, the impact resistance and pinhole resistance were inferior. In Comparative Example 4 in which the PBT / PETG ratio was 30/70 and the production ratio of smectic crystals was outside the range of the present invention, all evaluation items were “x”. Comparative Example 5 in which the degree of orientation of the outermost layer was outside the range of the present invention was inferior in easy-openability, impact resistance, and pinhole resistance. In Comparative Example 6, in which the heat treatment temperature was low and the ratio of formation of smectic crystals was outside the range of the present invention, all evaluation items were “x”.

  From the above, it was found that by applying the present invention, the easy-openability and impact resistance of the multilayer film and the package can be further improved. In addition, it has been found that the multilayer film and the package to which the present invention is applied are excellent in pinhole resistance, oxygen barrier property and aroma retention.

1 outermost layer 2 innermost layer 3 intermediate layer 4 first adhesive layer 5 second adhesive layer 6 third adhesive layer

Claims (5)

Having an outermost layer and an innermost layer;
The outermost layer includes at least one selected from polyethylene terephthalate, polybutylene terephthalate and glycol-modified polyethylene terephthalate,
The innermost layer comprises a polyolefin;
The outermost layer has an MD orientation degree α1 of 0.2 to 2.5 measured by infrared dichroism, and a TD orientation degree β1 of 0.2 to 2 measured by infrared dichroism. .5,
The innermost layer has an MD orientation degree α2 of 0.2 to 2.5 measured by infrared dichroism, and a TD orientation degree β2 of 0.2 to 2 measured by infrared dichroism. .5,
A multilayer film having a ratio S1 / S2 of 1/99 to 10/90 of the peak area S1 of the melting point of smectic crystal and the peak area S2 of the melting point of monoclinic crystal measured by a heat flux differential scanning calorimeter . Having an intermediate layer between the outermost layer and the innermost layer;
The multilayer film according to claim 1, wherein the intermediate layer includes at least one selected from polyamide, polyvinyl alcohol, and aluminum.   The ratio represented by the orientation degree α1 / the orientation degree β1 is 0.5 to 2.0, and the ratio represented by the orientation degree α2 / the orientation degree β2 is 0.5 to 2.0. The multilayer film according to claim 1 or 2.   The package in which the multilayer film as described in any one of Claims 1-3 is used, the said innermost layer forms an inner surface, and the said outermost layer forms an outer surface. A method for producing a multilayer film according to any one of claims 1 to 3,
A step of providing an inner layer material containing polyolefin on one surface of an outer layer material containing at least one selected from polyethylene terephthalate, polybutylene terephthalate and glycol-modified polyethylene terephthalate to obtain a laminate;
Applying heat treatment to the laminate;
The manufacturing method of the multilayer film which has this.

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