JP2003145696A - Laminated film, sealant film, and package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film excellent in easy openability, low temperature heat sealability and steam barrier properties. SOLUTION: The laminated film comprises at least two layers, that is, a resin composition layer, which contains 50-80 pts.mass of a propylene/α-olefin random copolymer (a) with an α-olefin content of 3-10 mass % and a melt flow rate of 5-35 g/10 min, 5-20 pts.mass of high density polyethylene (b) with a melt flow rate of 1-25 g/10 min, 5-20 pts.mass of linear low density polyethylene (c) with a melt flow rate of 1-10 g/10 min and 10-40 pts.mass of a butene resin (d) [(a)+(b)+(c)+(d)=100 pts.mass], and a propylene resin layer containing a propylene resin (e) with a melt flow rate of 1-10 g/10 min. The sealant film using the laminated film and the package using them are also disclosed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated film, a sealant film, a laminated body and a packaging body, and particularly to a food or medical packaging material excellent in easy-opening property, whitening property, steam barrier property and low temperature heat-sealing property. The present invention relates to a laminated film, a sealant film, a laminated body and a packaging body suitable as

[0002]

2. Description of the Related Art Conventionally, polyolefin films have been used as various food packaging materials and various medical packaging materials by taking advantage of their inexpensiveness, heat resistance, chemical resistance, and easy heat sealability.

In food packaging, aluminum foil, vinylidene chloride resin, saponified ethylene-vinyl acetate copolymer resin, etc. are used as gas barrier layers in combination with polyamide resin layers, polyester resin layers, etc., and polypropylene, polyethylene, etc. are used as sealant layers. Polyolefin resin is used. On the other hand, in medical packaging as well, a polyolefin resin is similarly used as a sealant layer.

As an easily-openable sealant film,
A method using a resin composition in which polypropylene and polyethylene are mixed in the sealant layer and a method using a resin obtained by graft-polymerizing styrene to a polyolefin resin are known.

As a sealant film for a package for knurling a medical device package, a resin composition obtained by mixing linear low density polyethylene with polypropylene having a low melting point is used as a sealant layer, and a base layer is formed on this layer. A laminate of homopolypropylene is used as the material.
This sealant film has a feature that when the package is opened, the heat-sealed portion (peeling portion) is whitened, so that it can be visually confirmed that the package is reliably heat-sealed.

However, since the heat-sealing strength (peeling strength of the heat-sealing portion) is as strong as 11.8 N / 15 mm width or more, it is difficult to open. In addition, since the heat-seal temperature range is narrow, the heat-seal strength is likely to change due to some changes in heat-sealing conditions. There was a problem that they could not be opened because they were heat-sealed.

As an example of the prior art document relating to the easily openable sealant film, for example, a melt index of 2 to
A thickness of 5 to 25 containing 100 g / 10 minutes of a crystalline polypropylene resin and polyethylene having a melt index of 2 to 50 g / 10 minutes in a weight ratio of 50:50 to 95: 5.
A package having a heat-sealing resin layer made of a resin composition layer having a thickness of μm (Japanese Patent Laid-Open No. 58-1672), a base resin made of crystalline polypropylene or a crystalline propylene-ethylene copolymer, and vinyl acetate containing A container having a film layer formed of a blend of 8 to 30% by weight of ethylene-vinyl acetate copolymer in an amount of 8 to 5% by weight and having an unsealing strength of 100 to 1700 g / cm after heat sterilization (Japanese Patent Laid-Open Publication No. 5 (1999) -5120).
7-28777) and the like. These have problems that they are inferior in low-temperature heat sealability, have too high unsealing strength, are inferior in whitening property of the heat-sealed portion at the time of unsealing, and in extreme cases, do not whiten at all.

[0008] As a prior document relating to the combination of polyethylene and a butene-based polymer, for example, polyethylene and polybutene-1 for preventing strain cracking due to contact between a bottle made of polyethylene, a pipe, an electric wire coating, etc. and a viscous liquid.
A method of blending and (Japanese Patent Publication No. 39-22351) is disclosed.

[0009] As a prior document relating to the combination of a propylene resin and a butene polymer, for example, "Latest Laminating Manual" [published on page 865 (1989) Processing Technology Research Group] has melting temperatures of 71 ° C and 75 ° C. It is disclosed that low temperature heat sealability is improved by blending 50% by weight of polybutene-1 at 30 ° C. with polypropylene. Japanese Unexamined Patent Publication (Kokai) No. 50-14741 discloses polypropylenes 80 to 90 which are excellent in low temperature heat sealability and optical characteristics.
Disclosed is a thermoplastic film consisting of 10% by weight and 10 to 20% by weight of polybutene-1.

However, these prior documents do not disclose or suggest the object and solution of the present invention.

[0011]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminated film or the like suitable as a packaging material for food or medical use. Another object of the present invention is to provide a sealant film having excellent openability, low temperature heat sealability (heat seal strength stability), and water vapor barrier property. Another object of the present invention is to provide a laminated film, a sealant film, a laminated body, a packaging body, and the like which are excellent in whitening property and have excellent appearance such as no feathering phenomenon (fluffing).

[0012]

As a result of intensive studies, the present inventors have found that the above problems can be achieved by laminating a specific resin composition layer and a propylene resin layer, and based on this finding Based on this, the present invention has been completed.

That is, the present invention provides the following (1) to (1)
The present invention relates to the laminated film shown in 2), a method for producing the laminated film, a sealant film, a laminate, a package, a method for producing the package, and a medical device.

(1) Propylene-α-olefin random copolymer (a) 50 to 80 having an α-olefin content of 3 to 10% by mass and a melt flow rate of 5 to 35 g / 10 min.
5 parts by mass of high-density polyethylene (b) having a melt flow rate of 1 to 25 g / 10 minutes, 5 to 20 parts by mass of linear low-density polyethylene (c) having a melt flow rate of 1 to 10 g / 10 minutes, and Butene-based resin (d) 10-4
0 parts by mass (however, (a) + (b) + (c) + (d) = 1
At least two layers of a resin composition layer [(A) layer] containing 100 parts by mass] and a propylene resin layer [(B) layer] containing a propylene resin (e) having a melt flow rate of 1 to 10 g / 10 min. A laminated film characterized in that. (2) The laminated film according to (1), wherein the propylene-α-olefin random copolymer (a) is a propylene-ethylene random copolymer. (3) The laminated film as described in (1) or (2), wherein the butene-based resin (d) is polybutene-1.

(4) Polybutene-1 has a melt flow rate of 0.5 to 15 g / 10 minutes and a melting point of 100 to 140 ° C.
The laminated film according to (3), wherein (5) The laminated film as described in any of (1) to (4), wherein the propylene resin (e) is a propylene homopolymer. (6) In the method for producing a laminated film according to any one of (1) to (5), the production method is a die temperature of 20.
A method for producing a laminated film, which is a coextrusion molding method performed at 0 to 280 ° C and a cooling temperature of 20 to 90 ° C.

(7) The laminated film as described in any of (1) to (5), which is a resin composition layer [(A) layer].
Is a sealant layer. (8) A laminate comprising the sealant film according to (7) and a gas barrier layer and / or a protective layer. (9) A package having the sealant film according to (7).

(10) A method for producing a package according to (9), which comprises a step of heat-sealing by knurling. (11) A medical device which is packaged in the package according to (9). (12) The medical device according to (11), which is a blood glucose measuring electrode.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The resin composition layer in the present invention [hereinafter sometimes referred to as "(A) layer"]. ] The propylene-α-olefin random copolymer (a) [hereinafter sometimes referred to as “RPP” or the component (a)). ] Is a random copolymer of propylene and an α-olefin having 2 to 12 carbon atoms (excluding 3). As the α-olefin, ethylene, 1-butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-
Dimethyl-1-pentene, vinylcyclopentane, vinylcyclohexane and the like can be mentioned. These α-olefins may be used alone or in combination of two or more. Of these α-olefins, ethylene is preferable. The content of α-olefin is usually 3 to 10% by mass, preferably 4 to 9% by mass, and more preferably 5 to 8% by mass. When the content of α-olefin is less than 3% by mass, low-temperature heat-sealing property is not exhibited, which is not preferable. On the other hand, when the content of α-olefin exceeds 10% by mass, heat resistance decreases. When the heat resistance decreases, in the sealant film having the layer (A) of the laminated film of the present invention described later as a sealant layer, the sealant layer flows and becomes thin, causing a decrease in heat seal strength, or the portions where the sealant layer flows. In many cases, problems such as fusion bonding and heat-seal portion cannot be peeled off occur.

The low temperature heat sealability referred to in the present invention is 1
At a heat sealing temperature in the range of 40 to 160 ° C., the heat sealing strength is in the range of 3 to 10 N / 15 mm, preferably 5 to 10 N / 15 mm width. If the heat-sealing strength is within the above range, the practical standard of easy-opening property for a package is satisfied. When a resin composition based on a conventional propylene-α-olefin random copolymer is used as a sealant layer of a sealant film, the heat seal strength strongly depends on the heat seal temperature, and the heat seal temperature is 160 ° C (about Below the melting point of polypropylene), especially below 140 ° C., the heat-sealing strength showing a practically easy-opening property could not be obtained because of a sharp decrease. Therefore, in order to stably obtain a package having a heat-sealing strength showing a practical easy-opening property, it has been unavoidable to control the heat-sealing temperature to around 160 ° C. However, if the sealant film of the present invention is used, the low temperature heat sealability is improved,
The heat seal strength suitable as an easily openable sealant film can be obtained in the heat seal temperature range of 140 to 160 ° C., and is stable even if there is some variation in the heat seal temperature at the time of manufacturing the package as compared with the conventional case. A package having the above heat seal strength can be easily manufactured.

Melt flow rate of RPP (hereinafter referred to as "MF
R ”. ) Is 5 to 35 g / 10 minutes, preferably 10 to 30 g / 10 minutes, more preferably 15 to 2
It is 5 g / 10 minutes. The MFR here is JIS
According to K7210, temperature 230 ℃, load 21.18N
It is the value measured under the condition of. If the MFR is less than 5 g / 10 minutes, the heat-sealing property is poor, which is not preferable. On the other hand, when it exceeds 35 g / 10 minutes, when the knurl sealing is performed, the sealant layer flows, the sealant layer becomes thin and the heat seal strength is lowered, or the sealant layer is melted and adhered to each other. In many cases, problems such as the inability to peel off parts occur.

The heat-sealing property referred to in the present invention is a comprehensive judgment of the above-mentioned low-temperature heat-sealing property as a package, the degree of whitening of the peeled portion when opened, and the degree of feathering (fluffing) of the peeled portion. Indicating that the heat-sealing property is excellent means that in addition to having the above-mentioned low-temperature heat-sealing property as a package, it is possible to easily visually confirm that the peeled portion is sufficiently whitened when opened, and the feather of the peeled portion is used. The ring is invisible. On the other hand, when any one of the above three requirements is not satisfied, the heat seal property is evaluated to be inferior.

The high-density polyethylene (b) used for the layer (A) in the present invention [hereinafter referred to as "HDPE" or (b)
Sometimes called an ingredient. ] Has an MFR of 1 to 25 g / 10
Minutes, preferably 2 to 18 g / 10 minutes, more preferably 3 to 12 g / 10 minutes. In addition, MF here
R is a value measured in accordance with JIS K7210 under the conditions of a temperature of 190 ° C. and a load of 21.18N. MFR is 1g
If it is less than / 10 minutes, the low-temperature heat-sealing property and the whitening property are poor, which is not preferable. On the other hand, if it exceeds 25 g / 10 minutes, the film is likely to tear in the longitudinal direction and a feathering phenomenon at the time of peeling is not preferable. In addition, JIS of HDPE
The density by the 7112D method is 0.945 to 0.970 g.
/ Cm ³ is preferable, and 0.946 to 0.965 g / cm ³
Is more preferable, and 0.947 to 0.958 g / cm ³ is even more preferable. When the density is less than 0.945 g / cm ³ , not only the water vapor barrier property is poor, but also the whitening property at the time of peeling tends to be poor. On the other hand, 0.970 g /
If it exceeds cm ³ , the low-temperature heat-sealing property and the whitening property are likely to be impaired.

The linear low-density polyethylene (c) used in the layer (A) in the present invention [hereinafter sometimes referred to as "LLDPE" or component (c)). ] Refers to a copolymer of ethylene and one or more kinds selected from α-olefins having 3 to 20 carbon atoms. The catalyst used at the time of production is not particularly limited, and those produced by a single site type catalyst and a Ziegler type catalyst can be used. Among the α-olefins having 3 to 20 carbon atoms, those having 3 to 12 carbon atoms are preferable. Specifically, propylene, 1-butene, 1-pentene, 4-methyl 1-pentene, 1-hexene, 1-octene, 1-decene and 1
-Dodecene and the like, preferably propylene, 1
-Butene, 1-hexene and 1-octene. The content of α-olefin in the copolymer is usually 1 to 30.
It is mol%, preferably 3 to 20 mol%.

According to JIS K 7210 of LLDPE, the MFR measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N is 1 to 10 g / 10 minutes, preferably 2 to 8
g / 10 minutes, more preferably 2.5 to 5 g / 10 minutes. When the MFR is less than 1 g / 10 minutes, the heat seal strength becomes too strong, which is not preferable. On the other hand, MFR is 10
If it exceeds g / 10 minutes, a feathering phenomenon is likely to occur at the time of opening, and the appearance of the peeled surface is deteriorated, which is not preferable.

In addition, LLDPE JIS K 7112
The density by the D method is usually 0.920 to 0.935 g / c
m ³ , preferably 0.922 to 0.933 g /
cm ³ , more preferably 0.925 to 0.932 g / c
m is ^3. If the density is less than 0.920 g / cm ³ ,
Water vapor barrier property, whitening property and easy opening property are inferior easily,
If it exceeds 0.935 g / cm ³ , the low temperature heat sealability tends to be poor.

The butene-based resin (d) used in the layer (A) of the present invention [hereinafter sometimes referred to as component (d)]. ]
Examples thereof include, but are not limited to, ethylene-butene copolymer and polybutene-1. Of these, polybutene-1 is preferred.

The ethylene content of the ethylene-butene copolymer is usually 70 to 98% by mass, preferably 72 to
It is 96% by mass, more preferably 75 to 95% by mass.
When the ethylene content is 70% by mass or less, heat resistance, peeling appearance and whitening property tend to be poor, and when it exceeds 98% by mass, easy-opening property and whitening property tend to be poor.

JIS K7 of ethylene-butene copolymer
210, MFR measured at a temperature of 230 ° C. and a load of 21.18 N is preferably 0.1 to 20 g / 10 minutes,
It is preferably 0.2 to 9 g / 10 minutes, more preferably 0.5 to 8 g / 10 minutes. MFR is 0.1g / 1
If it is 0 minutes or less, the easy-open property tends to be poor, and 10 minutes /
If it exceeds 10 minutes, the peeling appearance and the whitening property tend to be poor.

The polybutene-1 (hereinafter referred to as "PB") used in the present invention is a polyolefin which is usually polymerized from butene-1 as a raw material and is the same as polyethylene or polypropylene. Generally, PB has a high molecular weight and high isotacticity. As a polymerization method, a method of using butene-1 as a solvent using a Ziegler-Natta catalyst, or a solution polymerization method using a hydrocarbon solvent such as hexane or heptane is used.

Since PB has a second-order transition point lower than that of polypropylene, PB has a higher elastic modulus at room temperature to a lower temperature than polypropylene [D. G. Natta et. a
l: J. Polymer Sci. Vol. 25 p
119 (1957)], and is known as a polymer having rubber elasticity. Further, PB is superior to polyethylene and polypropylene in mechanical properties such as tensile strength, impact strength and tear strength, and is therefore used as a raw material for pipes, tubes and modifiers. In the film field, PB is used for the purpose of imparting a low temperature heat sealability or an easy peelability by blending with other resin. Regarding the properties and applications of these PBs, for example, "Latest Laminating Manual"
Pp. 861-866 (1989) Published by Processing Technology Research Group
I. D. Rubin, Poly (1-Butene)-
its Preparation and Prop
rties ”, Gordon and Break
Science Publishers, inc. , N
For example, see ew York (1968).

PB ASTM D1 used in the present invention
MFR measured in accordance with 238E is 0.5 to 15 g.
/ 10 minutes is preferable, 0.8 to 12 g / 10 minutes is more preferable, and 1 to 10 g / 10 minutes is even more preferable. If the MFR is less than 0.5 g / 10 minutes, the heat-sealing strength may be too high, on the other hand, 15 g
When it exceeds / 10 minutes, the peeling of the heat-sealed portion may cause a feathering phenomenon in the peeled portion, or the whitening property at the time of peeling may be poor.

The melting point measured by differential scanning calorimetry (DSC) according to JIS K 7121 of PB is preferably 100 to 140 ° C, and 110 to 135 ° C.
Is more preferable and 115-130 degreeC is still more preferable. When the melting point is less than 100 ° C., peeling off the heat-sealed portion causes a feathering phenomenon at the peeled portion,
It tends to be inferior in whitening property during peeling. On the other hand, the heat seal strength exceeding 140 ° C and the whitening property tend to be poor.

Examples of commercially available products of PB are sold by Shell Chemical Co. and Mitsui Chemical Co., Ltd. under the trade name of "Bulon", and these can be preferably used.

Regarding the blending ratio of the components (a), (b), (c) and (d) contained in the layer (A),
(A) Component 50 to 80 parts by mass, (b) Component 5 to 20 parts by mass, (c) Component 5 to 20 parts by mass and (d) Component 10 to 4
0 parts by mass (however, (a) + (b) + (c) + (d) = 1
00 parts by mass]. Preferably, component (a) 6
0 to 78 parts by mass, (b) component 5 to 18 parts by mass, (c) component 5 to 16 parts by mass and (d) component 15 to 25 parts by mass, particularly preferably (a) component 65 to 75 parts by mass. ,
The ranges of (b) component 8 to 15 parts by mass, (c) component 8 to 14 parts by mass and (d) component 17 to 23 parts by mass are preferable.
When the amount of the component (a) is less than 50 parts by mass, not only the pressing portion by the heat seal bar but also the vicinity thereof is heat-sealed, the external appearance is impaired, the heat-sealing strength is increased, and the easy-open property is deteriorated, which is not preferable. On the other hand, if it exceeds 80 parts by mass, the low-temperature heat-sealing property is deteriorated, which is not preferable. (B) component is 5
When the amount is less than the amount by mass, the ease of opening is poor and it is not preferable. On the other hand, when the amount is more than 20 parts by mass, it peels into a fibrous shape at the time of peeling, which impairs the appearance of the peeled surface and deteriorates the low-temperature heat-sealing property, which is not preferable. When the amount of the component (c) is less than 5 parts by mass, the ease of opening is poor and it is not preferable. On the other hand, if it exceeds 20 parts by mass, feathering during peeling is likely to occur and the appearance of the peeled surface is deteriorated, which is not preferable. When the amount of the component (d) is less than 10 parts by mass, the easy-open property is poor and the whitening property is poor, which is not preferable. On the other hand, if it exceeds 40 parts by mass, the water vapor barrier property is poor, the heat seal strength is lowered, and the whitening property is poor, which is not preferable.

Next, in the laminated film of the present invention, a propylene-based resin layer containing the propylene-based resin (e) [hereinafter sometimes referred to as (B) layer]. ] Will be described. The propylene-based resin (e) is a propylene homopolymer or propylene and α having 2 to 12 carbon atoms (excluding 3).
-Propylene which is a random copolymer with olefin-
An α-olefin random copolymer can be preferably used.
Of these, a propylene homopolymer is preferable because it has excellent openability and water vapor barrier properties. As α-olefin, ethylene, 1-butene, 3-methyl-1
-Butene, 3-methyl-1-pentene, 4-methyl-1
-Pentene, 4-dimethyl-1-pentene, vinylcyclopentane, vinylcyclohexane and the like.
These α-olefins may be used alone or in combination of two or more. Of these α-olefins, ethylene is preferable.

The content of α-olefin in the propylene-α-olefin random copolymer is 1.5% by mass.
The following is preferred, 1.0% by mass or less is more preferred,
It is particularly preferably 0.8% by mass or less. When the content of the α-olefin component exceeds 1.5% by mass, the water vapor barrier property and the easy-open property tend to be poor, and the laminate laminated with other base material may be broken at the time of peeling. .

The MFR of the propylene resin (e) is 1 to
10 g / 10 minutes, preferably 1-8 g / 10 minutes,
It is more preferably 1.5 to 5.0 g / 10 minutes. MFR is 1
If it is less than 10 minutes, the low-temperature heat-sealing property and the whitening property of the peeled portion are poor. On the other hand, when the MFR exceeds 10 g / 10 minutes, it tends to tear in a specific direction or causes a feathering phenomenon during peeling.

The method for producing the laminated film of the present invention is not particularly limited, and a known molding method can be used. For example, if necessary, additives are added to the resin components of each layer of the laminated film, and the components are mixed with a mixing machine such as a mixing roll, Banbury mixer, Henschel, tumbler, and ribbon blender, and then kneaded using an extruder. Examples of the method include pelletizing or direct dry blending, and then forming a film by an extrusion laminestone molding method, a coextrusion inflation molding method, a coextrusion T-die molding method, or the like. When a laminated film comprising at least two layers of the (A) layer and the (B) layer of the present invention is obtained by the coextrusion molding method among these, the die temperature is 200 to 280 ° C.
As a film, and using a chill roll or the like, a cooling temperature of 20 to
Molding at 90 ° C. is preferable because it is possible to obtain a material excellent in water vapor barrier property and whitening property.

The sealant film of the present invention is a laminated film comprising at least two layers of the resin composition layer [(A) layer] and the propylene resin layer [(B) layer] of the present invention, and the (A) layer As a sealant layer.
The layer (B) is used as a base material layer of the sealant film. The layer structure of the sealant film is (A) layer /
A layer structure composed of two types and two layers of the (B) layer is preferable from the viewpoint of functionality and economical efficiency, but for reasons such as production and form of the package, (A) layer / (B) layer / (A) A two-kind three-layer structure consisting of layers, or (A) layer / (B) layer / other layers,
A multi-layer structure composed of (A) layer / other layer / (B) layer may be used. The other layer is preferably a polyolefin resin layer. Among these layer constitutions, it is preferable that the (A) layer and the (B) layer are laminated adjacent to each other. Adjacent to each other improves the stability of heat-sealing strength, and avoids the situation where it becomes difficult to take out the contents of the package due to melting and adhesion in the vicinity of the heat-sealing portion, and steam. It also has excellent barrier properties.

Regarding the thickness ratio of the (A) layer and the (B) layer of the sealant film of the present invention, the (A) layer: (B) layer =
The range of 0.05 to 0.3: 0.95 to 0.7 is suitable. Preferably (A) layer: (B) layer = 0.08 to 0.2
5: 0.92 to 0.75. More preferably (A) layer: (B) layer = 0.1-0.2: 0.9-0.8
Is the range. When the thickness ratio of the (A) layer is less than 0.05, when heat sealing is performed, a part where the (B) layers are heat-sealed partially occurs, the heat-sealing strength becomes high, and the package In some cases, there is a problem that the heat seal ends at the time of unsealing, and it becomes difficult to take out the contents. On the other hand, when the thickness ratio of the layer (A) exceeds 0.3, feathering may occur or the water vapor barrier property of the package may be deteriorated.

With respect to the thickness of the sealant film of the present invention, those having a thickness in the range of 20 to 80 μm satisfy the object of the present invention and can be preferably used. More preferably 20-60
μm, particularly preferably 25 to 50 μm. Also,
The thickness of the layer (A) is preferably 3 to 15 μm in consideration of moisture invasion from the end surface of the package when the package is formed.

The laminate of the present invention is characterized by containing the sealant film of the present invention and a gas barrier layer and / or a protective layer. The gas barrier layer and the protective layer can be obtained by laminating a laminated film or a sealant film with or without an adhesive.
As the adhesive, specifically, urethane-based adhesive, polyester-based adhesive, and maleic anhydride-modified polypropylene can be preferably used. When the gas barrier layer and / or the protective layer are laminated on the sealant film, they are laminated on the (B) layer side of the sealant film.

Examples of the gas barrier layer include a layer made of an aluminum foil, a metal vapor deposition film, a silicon oxide vapor deposition film, a vinylden chloride resin, and a saponified ethylene-vinyl acetate copolymer. The protective layer is a layer used for improving mechanical strength and the like when formed into a package, and specific examples thereof include a polyester resin layer, a polyamide resin layer, and a polycarbonate resin layer. Further, other polyolefin-based resin layers, oxygen absorbing layers, printing layers and the like may be further laminated and used in order to satisfy various properties required when the package is formed, within a range that does not impair the object of the present invention. . The print layer is a layer that imparts printability when used as a package, and specifically, a polyester resin, a polybutylene terephthalate resin, a polyamide resin, or the like can be preferably used. Preferred examples of the layer structure of the laminate include sealant film / gas barrier layer / printing layer and sealant film / protective layer / gas barrier layer / printing layer.

The laminate of the present invention can be obtained by using a known molding method and molding machine, specifically, for example, an extrusion laminating molding method, a dry laminating molding method or the like.

The package of the present invention is characterized by using the sealant film of the present invention. Examples of the packaging body include those obtained by using the sealant film of the present invention and melting the layer (A) as a sealant layer and adhering it to form a packaging container or a packaging bag. Examples of the object to be sealed that is adhered to the layer (A) include a planar object such as a film and a three-dimensional container obtained by molding a sheet. A suitable example is also a package using the laminate of the present invention.

The material to be sealed is not particularly limited as long as it can be bonded to the layer (A), but is preferably polyolefin. As the polyolefin, specifically, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polybutene,
Homopolymers of olefins such as poly-4-methylpentene-1, copolymers of two or more kinds of α-olefins such as ethylene, propylene, 1-butene, 1-hexene and 1-octene, ethylene, propylene, etc. Of olefin and maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo- [2,2,1] -hept-5-ene-
Copolymers (including graft copolymers) with unsaturated dicarboxylic acid anhydrides such as 2,3-dicarboxylic acid anhydrides, ethylene- (meth) acrylic acid copolymers, ethylene- (meth) acrylic acid esters Copolymers such as copolymers with ethylene and unsaturated carboxylic acids or unsaturated carboxylic acid esters, ethylene- (meth) acrylic acid ester-maleic anhydride copolymers such as ethylene terpolymers and the like. To be Of these, polypropylene and linear low-density polyethylene are preferable.

Further, a particularly preferred embodiment of the package of the present invention is a package in which substantially all of the heat-sealing surface is the layer (A) of the sealant film of the present invention.
This package is a good package having excellent openability, low-temperature heat-sealing property, steam barrier property, and excellent appearance such as whitening property and no feathering phenomenon (fluffing). A preferred example of this package is a package in which two resin composition layers of the laminate having the sealant film of the present invention are placed so as to be in contact with each other with each resin composition layer being the innermost surface, and the package is packaged so as to be sealed. And a package in which the laminate of the present invention is folded so that the resin composition layer is on the inside and the packaged object is sealed.

When the package of the present invention is manufactured by using heat sealing, it is preferable that the heat sealing is knurling. The heat-sealing temperature can be appropriately changed depending on the heat resistance of the packaged object, etc., but it is preferably about 120 to 180 ° C. from the viewpoint of easy opening.

The knurled seal is a form of heat seal in which a material to be fused is heat-melt-bonded by using a heat seal bar having a pattern such as a twill pattern or a flat pattern, and the stability of the seal strength, It is preferably used for packages that require water vapor barrier properties. When a flat heat seal bar is used, it is possible to seal the entire seal area in a plane wide and at the same time by pressure contact with the entire surface of the flat plate, so it is easy to close air bubbles in the seal area, and it is generated at the time of sealing. However, there is no escape area for expansion and contraction of the film, and shrinkage wrinkles occur in the seal portion, making it difficult to obtain a uniform heat-sealed state as a whole of the seal portion. Further, when the package is opened, variations in the sealing strength are likely to occur, which causes inconvenience that stable sealing strength cannot be obtained. On the other hand, if the knurled seal is used, such inconvenience can be eliminated.

The reason why the laminated film, sealant film and package of the present invention have excellent properties is not clear, but it is considered as follows. When the package using the sealant film of the present invention is peeled off, cohesive peeling due to cohesive failure occurs in the components (a), (b), (c) and (d).
It occurs in the resin composition layer containing a specific amount of the components, and exhibits excellent openability and whitening properties.

In particular, the reason why the whitening property, which is one of the effects of the present invention, is excellent is not clear, but since the component (d) constituting the resin composition layer has a larger molecular weight than the other components and has a large cohesive energy. , When the package is peeled off, (d)
It is presumed that this is due to the generation of fine voids at the interface between the component and other components.

With respect to the constituent material of each layer constituting the present invention, other additives conventionally used in thermoplastic resins (for example, antioxidant, weather resistance stabilizer, antistatic agent, lubricant, antiblocking agent, Anti-fog agents, dyes, pigments, oils, waxes, fillers, etc.) and other thermoplastic resins can be appropriately added within a range that does not impair the object of the present invention.

Examples of such additives include 2,5-di-t-butylhydroquinone and 2,2 as an antioxidant.
6-di-t-butyl-p-cresol, 4,4'-thiobis- (6-t-butylphenol), 2,2-methylene-bis (4-methyl-6-t-butylphenol), octadecyl 3- (3 ', 5'-di-t-butyl-1'-
Hydroxyphenyl) propinate, 4,4′-thiobis- (6-butylphenol), as an ultraviolet absorber ethyl-2-cyano-3,3-diphenylacrylate, 2- (2′-hydroxy-5-methylphenyl) benzo Triazole, 2-hydroxy-4-octoxybenzophenone, dimethyl phthalate, diethyl phthalate as plasticizer, wax, liquid paraffin, phosphoric acid ester, pentaerythritol monostearate, sorbitan monopalmitate, sulfuric acid as antistatic agent Oleic acid, polyethylene oxide, carbon wax, ethylene bis stearamide, butyl stearate as a lubricant, fatty acid amide (stearic acid amide, oleic acid amide, erucic acid amide, etc.), carbon black as a colorant, phthalocyanine, Nakuridon, indoline, azo pigments, titanium oxide, red iron oxide, glass fiber as a filler, asbestos, mica, wollastonite,
Calcium silicate, aluminum silicate, calcium carbonate, as a blocking inhibitor, silicate-based (calcium silicate, aluminum silicate, etc.), silicone-based, zeolite-based, talc, polymethylmethacrylate (PMM)
A) Particles and the like can be mentioned. Also, many other polymer compounds can be blended to the extent that the effects of the present invention are not impaired.

Since the package of the present invention has a feature that the heat-sealed portion is surely whitened when the package is opened, it can be easily visually confirmed that the package is reliably heat-sealed. It can be suitably used as a medical or food package. In particular, in addition to the whitening property, easy opening property, steam barrier property and the like are required, and it can be preferably used as a packaging material for medical devices requiring strict control. An example of such a medical device is a package used for packaging a blood glucose level measuring electrode, for example. As an embodiment of such an application, there can be mentioned a package in which two facing laminated films each have a heat-sealed portion where a part of the laminated film is knurl-sealed so as to have an article housing portion. In this case, the article storage unit may store only the blood glucose level measuring electrode, but may further store a desiccant. The desiccant is used to prevent the activity of the immobilized enzyme immobilized on the electrode from decreasing.

[0055]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The resins used in Examples 1 to 16 and Comparative Examples 1 to 7 are shown below.

[Resin Constituting Layer (A)] Component (a) PP1: Ethylene Content 6.5% by Mass, MFR 20 g /
10 minutes propylene-ethylene random copolymer. PP2: ethylene content of 4.5% by mass, MFR of 14.
2g / 10min propylene-ethylene random copolymer. PP3: ethylene content 5.8 mass%, MFR 6.8
g / 10 min propylene-ethylene random copolymer. PP4: ethylene content 1.2% by mass, MFR 12.
5 g / 10 min propylene-ethylene random copolymer. PP5: Propylene homopolymer having MFR of 20 g / 10 min.

Component (b) PE1: Density 0.953 g / cm ³ , MFR 5.2 g /
10 minutes high density polyethylene. PE2: Density 0.956 g / cm ³ , MFR 20.5 g
/ 10 minutes high density polyethylene. PE3: Density 0.949 g / cm ³ , MFR 12.5 g
/ 10 minutes high density polyethylene. PE4: Density 0.951 g / cm ³ , MFR 32 g / 1
0 minute high density polyethylene. PE5: Density 0.923 g / cm ³ , MFR 8.5 g /
10 minutes low density polyethylene.

Component (c) PE6: Density 0.929 g / cm ³ , MFR 2.1 g /
10 minutes linear low density polyethylene. PE7: Density 0.923 g / cm ³ , MFR 8.5 g /
10 minutes linear low density polyethylene. PE8: Density 0.932 g / cm ³ , MFR 3.5 g /
10 minutes linear low density polyethylene. PE9: Density 0.924 g / cm ³ , MFR 3.5 g /
10 minutes low density polyethylene.

(D) Component PB1: MFR 1.8 g / 10 min, density 0.915 g
/ Cm ^3, manufactured by Mitsui Chemicals is a polybutene-1 having a melting point of 125 ° C. (KK) "trade name: Byuron BL4000". PB2: MFR 20 g / 10 minutes, density 0.917 g /
"Buron BL7000" manufactured by Mitsui Chemicals, Inc., which is polybutene-1 having a cm ³ and a melting point of 123 ° C. PB3: MFR 1.0g / 10 minutes, density 0.900g
/ Cm ^3, Mitsui Chemicals is a polybutene-1 having a melting point of 75 ℃ (Ltd.) "product name: Byuron M2181". PEB: MFR 3.6 g / 10 min, density 0.88 g /
"Tufmer A", a product of Mitsui Chemicals, Inc., which is a cm ³ ethylene-butene copolymer.

[Resin Constituting Layer (B)] Component (e) PP6: MFR 4.5 g / 10 min propylene homopolymer. PP7: Propylene homopolymer of MFR 2.4 g / 10 min. PP8: MFR 15.4 g / 10 min propylene homopolymer. PP9: ethylene content 1.2% by mass, MFR 4.8 g
/ 10 min propylene-ethylene random copolymer. PP10: ethylene content 3.5% by mass, MFR11.
8g / 10min propylene-ethylene random copolymer.

[Preparation of Test Pieces] [Kneading Treatment] A combination of (a) component, (b) component, (c) component and (d) component of the (A) layer constituting material was changed and mixed by a tumbler. After that, the twin-screw extruder (KT) manufactured by Kobe Steel, Ltd.
X37 type) and pelletized at a temperature of 190 to 210 ° C.

[T-die molding] Using the above kneaded pellets, a diameter of 65 mm and a die width of 1,300 mm
Using a T-die film molding machine manufactured by Toshiba Machine Co., Ltd.
At the die temperature of 260 ° C., the combination of the (A) layer constituent material and the (B) layer constituent material is appropriately changed to form a film, and then 50 ° C.
A laminated film was prepared by cooling to 1. In addition,
The layer constitution was a two-kind two-layer constitution consisting of (A) layer / (B) layer. Regarding the thickness of each layer, the thickness of the (A) layer was 6 μm and the thickness of the (B) layer was 32 μm.

[Dry Lamination] Next, a polyester film having a thickness of 12 μm and an aluminum foil having a thickness of 15 μm were applied to the obtained laminated film by a dry laminating method to produce polyester film / aluminum foil / polyester film / (B) layer / (A). It laminated | stacked so that it might become a layer and obtained the laminated body. As the adhesive, a urethane adhesive "Takelac A515" manufactured by Takeda Pharmaceutical Co., Ltd.
Was used as a main agent and "Takenate A50" manufactured by Takeda Yakuhin Kogyo Co., Ltd., which is a polyester adhesive, was used as a curing agent, and the thickness after drying was applied to be 2 μm.

[Heat Sealing] The peripheral edges of the obtained two laminated bodies were arranged with the layers (A) on the innermost surfaces, and using a heat sealer manufactured by Tester Sangyo Co., Ltd., a twill with an uneven inclination angle of 55 degrees. A knurled package was obtained by heat-sealing with an eye-shaped heat-sealing bar at a pressure of 0.2 MPa for 1 second. The heat seal temperature is 140
℃, 150 ℃ and 160 ℃.

[Physical Property Measurement Method] [Heat Seal Strength] The package was cut into a width of 15 mm and a 180 ° peel strength was obtained by using a tensile tester (RTA-100 type) manufactured by Orientec Co., Ltd. under a pulling speed of 300 mm / min. I asked. In addition, the test was performed 10 points, and the average value was calculated.

[Whitening] The whitening state of the peeled portion of the heat-sealed portion was visually observed for the test piece after the heat-sealing strength measurement of the package prepared at the heat-sealing temperature of 140 ° C. The evaluation was performed according to the following criteria. ◯: It is sufficiently whitened, and it is easy to confirm the whitening. △: It is white and it is difficult to confirm. ×: No whitening at all.

[Appearance] The peeled portion after the measurement of the heat-sealing strength was visually judged according to the following criteria for feathering (fluffing). ○: Feathering is not recognized at all. Δ: Feathering is partially recognized. X: Feathering is remarkable and the appearance is inferior.

[Water vapor permeation amount] According to ASTM E96, "Water vapor permeation tester PER" manufactured by Modern Control Co., Ltd.
MATRAN-W "was used to measure the water vapor transmission amount of the laminated film at a temperature of 37.8 ° C and a relative humidity of 90%.

Table 1 shows the results of measuring the heat sealability and the amount of water vapor transmission using the laminated film shown in Table 1. Examples 17 to 18 and Comparative Examples 8 to 9 The thickness of the (A) layer is 12 μm, and the thickness of the (B) layer is 48 μm.
Other than the above, the same procedure as in Example 1 was performed.

[0070]

[Table 1]

[0071]

The laminated film, sealant film and package of the present invention are excellent in easy-opening property, low temperature heat sealing property (stability of heat sealing strength) and water vapor barrier property. In addition, it has excellent whitening properties and a feathering phenomenon (fluffing).
Since it has a good appearance, such as lacking, it is useful in the fields of food and medical packaging materials. It is particularly suitable in the field of packaging materials for knurling.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // (C08L 23/14 C08L 23:06 23:06 23:08 23:08 23:20 23:20) (C08L 23/16 23:06 23:08 23:20) (72) Inventor Takao Minamijutsu 2nd Nakanosu, Oita City, Oita Prefecture Showa Denko Plastic Products Co., Ltd. Oita Factory F-term (reference) 3E086 AB01 AC07 AC22 AD01 BA04 BA15 BB02 BB51 BB90 CA01 CA28 4F100 AK05A AK07B AK09A AK62A AK63A AK64.

Claims (12)

[Claims] 1. Propylene-α having an α-olefin content of 3 to 10% by mass and a melt flow rate of 5 to 35 g / 10 min.
-Olefin random copolymer (a) 50 to 80 parts by mass, high density polyethylene (b) 5 to 20 parts by mass with a melt flow rate of 1 to 25 g / 10 minutes, and linear chain with a melt flow rate of 1 to 10 g / 10 minutes. Low density polyethylene (c)
A resin composition layer [(A) containing 5 to 20 parts by mass and a butene-based resin (d) 10 to 40 parts by mass (however, (a) + (b) + (c) + (d) = 100 parts by mass] Layer] and a propylene-based resin layer [(B) layer] containing a propylene-based resin (e) having a melt flow rate of 1 to 10 g / 10 min, at least two layers. 2. The laminated film according to claim 1, wherein the propylene-α-olefin random copolymer (a) is a propylene-ethylene random copolymer. 3. The laminated film according to claim 1, wherein the butene-based resin (d) is polybutene-1. 4. The laminated film according to claim 3, wherein polybutene-1 has a melt flow rate of 0.5 to 15 g / 10 minutes and a melting point of 100 to 140 ° C. 5. The propylene-based resin (e) is a propylene homopolymer, wherein the propylene resin (e) is a propylene homopolymer.
The laminated film according to any one of 1. 6. The method for producing a laminated film according to claim 1, wherein the production method is a coextrusion molding method performed at a die temperature of 200 to 280 ° C. and a cooling temperature of 20 to 90 ° C. And a method for producing a laminated film. 7. The laminated film according to any one of claims 1 to 5, which comprises a resin composition layer [(A)
Layer] as a sealant layer. 8. A sealant film according to claim 7,
A laminate comprising a gas barrier layer and / or a protective layer. 9. A package comprising the sealant film according to claim 7. 10. A method for producing a package according to claim 9, wherein the method includes a step of heat-sealing by knurl sealing. 11. A medical device, which is packaged in the package according to claim 9. 12. The medical device according to claim 11, which is a blood glucose level measuring electrode.