JPH1199595A - Laminated film, lid material, and container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film of a styrene resin composition which exhibits easy peelability and easy openability and is excellent in the appearance of a peeled interface and also inn film rigidity, a lid material of the film, and a bag-shaped container of the film. SOLUTION: In a laminated film consisting at least of two layers, one surface layer is a sealant layer consisting at least of a resin selected from a styrene resin, an ethylene resin, and a propylene resin, and a layer of a styrene resin composition (X) exists adjacent to the sealant layer. The composition (X) contains 40-80 wt.% of an (A) component, 20-60 wt.% of a (B) component, and 0-40 wt. ∥% of a (C) component. The (A) component is a styrene resin, the (B) component is an olefin resin which has a solubility parameter (SP) of 8.45-8.70 and does not have a repeating unit derived from an aromatic vinyl compound, and the (C) component is an olefin resin other than the (B) component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated film comprising a styrenic resin composition, a lid comprising the laminated film, and a bag-like container comprising the laminated film.

[0002]

2. Description of the Related Art In packaging materials, it is common to form a laminate in which a heat seal (sealant) layer is formed on a base material. Examples of the sealant material include polyethylene, polypropylene, and ethylene copolymers. Olefin resins are mainly used. The laminate having the sealant layer formed thereon is used as a bag-shaped packaging container, or as a lid material of a cup-shaped or box-shaped packaging container made of plastic, paper, or the like. These packages need to have high sealing strength and excellent sealing properties, and also have excellent easy-opening properties (easy-opening properties) when the contents are used. In the case of a bag-shaped packaging container, the bag may be torn and opened, but in the case of a cup-shaped or box-shaped packaging container lid, the lid is often peeled off from the container body and opened. The material must be easy to peel from the container (easy peeling property).

[0003] As a sealant material having an easy-peeling property, a material mainly composed of an ethylene resin composition is disclosed, for example, in JP-A-7-207074. A sealant film made of an ethylene-based resin composition generally has low rigidity, so that when peeled from a container, the sealant material stretches like a string between a container and a lid, and the appearance of a peeling interface with the container is inferior. There was a problem. On the other hand, a styrene-based resin composition has also been used as a sealant material exhibiting easy-peeling properties, and is disclosed, for example, in JP-A-8-48849. A film made of an easy-peel material made of a styrene-based resin composition is characterized by having excellent rigidity as compared with a film made of an ethylene-based resin composition.

However, when these sealants exhibiting easy peeling properties are directly heat-sealed to an adherend such as a container as a sealant, the seal strength (peel strength) greatly changes depending on heat-sealing conditions such as temperature, pressure and time. In many cases, stable peel strength was not obtained. In addition, although peeling occurs between the sealant material and the adherend, in a region having a high peeling strength, cohesive failure peeling often occurs, and there is a problem that the appearance of the peeling interface is not good.

As a means for solving these problems, a laminated film having a sealant layer and a release layer is provided, and the sealant layer is completely fused to an adherend and delaminated at the interface between the sealant layer and the release layer ( A delamination type easy peel) has been proposed.
No. 89, in a multilayer film comprising a support layer made of polypropylene, a release layer made of a blend of olefin copolymer rubber and polypropylene and a polyethylene layer in this order, the release layer and the polyethylene layer Has a total thickness of 2.5 to 10 μm. However, they often consisted of a combination of polyethylene, polypropylene and mixtures thereof, and the stiffness of the film was low. Further, they are intended for containers made of an ethylene-based resin, containers made of paper laminated with an ethylene-based resin, or containers made of a propylene-based resin, and are not applicable to containers made of a styrene-based resin.

As an easy peel film of a delamination type using a styrene resin composition, for example, Japanese Patent Application Laid-Open No. 9-124070 discloses a heat seal sealing layer made of polyethylene as an outermost layer, and then a styrene resin. A film is disclosed in which an easily breakable layer made of a blend of an ethylene-based resin is laminated. However, this method is intended for containers made of ethylene resin, containers made of paper laminated with ethylene resin or containers made of propylene resin, and is not applicable to containers made of styrene resin. Was.

In this method, when a compatibilizer is not used in a blend of a styrene resin and an ethylene resin used in the easily breakable layer, a heat seal sealing layer made of the ethylene resin, When the easily breakable layer made of the ethylene-based resin blend was peeled off, stringing occurred and the appearance of the peeling interface was poor, so it was necessary to use at least 5 parts by weight of a compatibilizer. Examples of the compatibilizer for the styrene-based resin and the ethylene-based resin include hydrogenated styrene-based monomers such as hydrogenated styrene-isoprene block copolymer rubber and hydrogenated styrene-butadiene block copolymer rubber. Conjugated diene-based copolymers are used, but these are generally about 10 times more expensive than styrene-based resins and ethylene-based resins, and are inferior in cost when used in large amounts.

[0008]

In such a situation,
An object of the present invention is to provide an easy-peeling property, an easy-opening property, and excellent appearance of a peeling interface, and also excellent in film rigidity, a laminated film made of a styrene-based resin composition, a lid material made of the laminated film, and An object of the present invention is to provide a bag-shaped container made of a laminated film.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies on an easy peel film of a delamination type, and as a result, by using a specific styrene resin composition,
The inventors have found that the object of the present invention is achieved, and have completed the present invention.

That is, the present invention is a laminated film comprising at least two layers, one of which is a sealant layer composed of at least one resin selected from styrene-based resins, ethylene-based resins and propylene-based resins. And a layer composed of the following styrene resin composition (X) adjacent to the sealant layer. A styrene resin composition wherein the styrene resin composition (X) contains the following component (A) 40 to 80% by weight, component (B) 20 to 60% by weight, and component (C) 0 to 40% by weight. (A) component: styrene resin (B) component: solubility parameter (SP) is 8.45 to
An olefin-based resin which is 8.70 and does not contain a repeating unit derived from an aromatic vinyl compound in the polymer. Component (C): An olefin-based resin other than the component (B). A lid material characterized in that: Furthermore, the present invention is a bag-like container comprising the above-mentioned laminated film. Hereinafter, the present invention will be described in detail.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The styrenic resin composition (X) used in the present invention comprises the following component (A): 40 to 80% by weight, preferably 40 to 70% by weight, component (B): 20 to 60% by weight, Preferably 25-55% by weight and component (C) 0-4.
It contains 0% by weight, preferably 5 to 35% by weight. (A) component: styrene resin (B) component: solubility parameter (SP) is 8.45 to
An olefin resin having a polymer content of 8.70 and containing no repeating unit derived from an aromatic vinyl compound in the polymer (C) component: an olefin resin other than the component (B) Here, the styrene resin composition (X When the content ratio of the component (A), the component (B), and the component (C) is out of the range of the present invention, it is not preferable because easy peelability is not exhibited.

The styrene resin (A) used in the present invention is not particularly limited, and conventional polystyrene, rubber-modified polystyrene and mixtures thereof can be used. Among them, JIS K7 under the condition of a temperature of 200 ° C. and a load of 5 kg
The melt flow rate measured according to 210 is 1 to
Polystyrene or rubber-modified polystyrene having a weight of 20 g / 10 min, preferably 2 to 18 g / 10 min, and more preferably 3 to 15 g / 10 min is preferred.

The component (B) used in the present invention has a solubility parameter (SP) of 8.45 to 8.70 and a repeating unit derived from an aromatic vinyl compound in a polymer (hereinafter referred to as "aromatic compound"). (Referred to as "vinyl compound unit"). Solubility parameter (S
When P) is smaller than 8.45 or larger than 8.70, the balance between the seal strength and the easy peelability is poor. Here, the solubility parameter (SP) refers to Hildebr
According to the And-Scatchard's theory, the attractive force between molecules is defined. A detailed explanation is given in a general textbook on polymer chemistry, for example, “Polymer Blend, Saburo Akiyama et al., CMC Co., Ltd., 4th printing, 125-14.
4 (1991) ".
The solubility parameter may be determined by an experiment such as a viscosity method or a swelling degree method, or may be determined by calculation from a molecular structure. In the present invention, the method of calculating from a molecular structure proposed by Small is used. Using. For more information on this method, see “Journal of
Applied Chemistry (Journal of A
Applied Chemistry), Volume 3, 71-8
0 pages are described in detail in (1953) ". Thus, the solubility parameter was calculated using the following equation. SP value _{= ΣF i / V = ρ ·} ΣF i / M where, F _i is the molecular The molar attractive force of a constituent group such as an atom or an atomic group, a bond type, etc., V is a molar volume, ρ is a density, M is a molecular weight, and in the case of a polymer, the molecular weight of a repeating unit (that is, a monomer unit) Is shown.
The value of F _i are described in the two documents Smal
The value of 1 was used. Copolymers [rho, for .SIGMA.F _i and M, [rho of the homopolymer of the monomer units constituting the copolymer, and calculating the sum of those multiplied by the mole fraction of monomer units in the numerical values of .SIGMA.F _i or M Used.

A resin composition using an olefin resin containing an aromatic vinyl compound unit in a polymer is inferior in the balance between seal strength and easy peelability. Examples of the aromatic vinyl compound include α-alkyl-substituted styrenes such as styrene and α-methylstyrene, and nucleus-substituted alkylstyrenes such as p-methylstyrene.

The solubility parameter (SP) is 8.45 to
The olefin resin having a molecular weight of 8.70 and containing no aromatic vinyl compound unit in the polymer is selected from unsaturated carboxylic acids, unsaturated carboxylic esters, unsaturated carboxylic anhydrides, and vinyl acetate. Ethylene-based copolymers comprising a repeating unit derived from the above vinyl monomer (hereinafter referred to as "vinyl monomer unit") and a repeating unit derived from ethylene (hereinafter referred to as "ethylene unit") are exemplified. Examples include ethylene-unsaturated carboxylic acid copolymers, ethylene-
Unsaturated carboxylic acid ester copolymer, ethylene-unsaturated carboxylic acid anhydride copolymer, ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester-vinyl acetate terpolymer, two types of ethylene units Multi-component copolymers composed of the above unsaturated carboxylic acid ester units and the like can be mentioned.

Examples of the unsaturated carboxylic acid include acrylic acid and methacrylic acid. Further, as the unsaturated carboxylic acid ester, for example, ethyl acrylate,
Methyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate,
-Ethylhexyl methacrylate, stearyl methacrylate, glycidyl methacrylate and the like. Examples of the unsaturated carboxylic anhydride include maleic anhydride. Preferred specific examples of the component (B) include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl methacrylate copolymer. , Ethylene-ethyl methacrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-methyl methacrylate-
Glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, ethylene-
And maleic anhydride copolymer.

The content ratio of the vinyl monomer unit and the ethylene unit in the ethylene copolymer is appropriately determined within a range that gives a copolymer having a solubility parameter (SP) of 8.45 to 8.70. Can be done. The content of the vinyl monomer unit is preferably 5 to 60% by weight. Also,
The bonding mode of the vinyl monomer unit and the ethylene unit in the ethylene-based copolymer, for example, random, block,
The alternation is not limited at all. Among the specific examples of the component (B), an ethylene-methyl methacrylate copolymer and an ethylene-vinyl acetate copolymer are preferable, and the content of the methyl methacrylate unit is 15 to
More preferred is 50% by weight, preferably 20-45% by weight of ethylene-methyl methacrylate copolymer.

The component (C) used in the present invention comprises the above component (B)
An olefin resin other than the component. Examples of the olefin-based resin include an ethylene-based resin and a propylene-based resin. Specific examples of these include low density polyethylene,
Polyethylene such as high-density polyethylene, ethylene-butene-1 copolymer, ethylene-α-olefin copolymer such as ethylene-hexene-1 copolymer, polypropylene,
Examples include propylene-based polymers such as propylene-α-olefin block copolymers, propylene-α-olefin random copolymers, and mixtures thereof.

Among the above, ethylene resins include:
JIS K under the condition of temperature 190 ° C and load 2.16kg
Polyethylene, ethylene- having a melt flow rate measured according to 7210 of 0.2 to 10 g / 10 min.
α-olefin copolymers or mixtures thereof are preferred. Examples of the α-olefin of the ethylene-α-olefin copolymer include those having 4 to 10 carbon atoms such as butene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, and decene-1. α-olefins. Also, among the above, as the propylene-based resin,
JIS K under the conditions of a temperature of 230 ° C and a load of 2.16 kg
Polypropylene, propylene-α-olefin block copolymer, propylene-α having a melt flow rate measured in accordance with 7210 of 0.2 to 10 g / 10 min.
-Olefin random copolymers or mixtures thereof are preferred. Propylene-α-olefin block copolymer, α of propylene-α-olefin random copolymer
-Examples of the olefin include ethylene and butene-1.

The method of mixing the above components (A), (B) and (C) is not particularly limited, and each pellet is sufficiently mixed by dry blending or melt-kneaded by an extruder. Afterwards, any of those re-granulated into pellets may be used, but in order to improve the dispersibility of each component, it is more preferable to melt-knead with an extruder and then re-granulate into pellets.

The styrenic resin composition used in the present invention may contain a compatibilizer, a lubricant, an antiblocking agent, an antistatic agent, an antioxidant, a heat stabilizer, an ultraviolet absorber, a pigment, a dye, if necessary. , An antibacterial agent, an anti-fogging agent, and the like, and a plasticizer such as a mineral oil may be added as long as the effects of the present invention are not impaired. Especially,
Since the components (A) and (C) are hardly compatible with each other, it is preferable to use a compatibilizer when the amount of the component (C) is 10 to 40% by weight.

Examples of the compatibilizer for the component (A) and the component (C) include a hydrogenated styrene compound-conjugated diene copolymer. Among them, styrene-containing a repeating unit derived from styrene (hereinafter referred to as “styrene unit”) having a content of 30 to 80% by weight.
A hydrogenated product of an isoprene block copolymer rubber or a hydrogenated product of a styrene-butadiene block copolymer rubber is preferred. The addition amount of the hydrogenated styrene-based compound-conjugated diene-based copolymer is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the styrene-based resin composition.

The laminated film of the present invention is a laminated film composed of at least two layers, one of which is a sealant layer composed of at least one resin selected from styrene resin, ethylene resin and propylene resin, A layer made of the styrene resin composition (X) is provided adjacent to the sealant layer.

The styrenic resin, ethylene resin and propylene resin used in the sealant layer are not particularly limited. Examples of the styrenic resin include polystyrene, rubber-modified polystyrene, styrene-butadiene block copolymer and mixtures thereof. No. Examples of the ethylene resin include polyethylene such as low-density polyethylene and high-density polyethylene, and ethylene-α such as ethylene-butene-1 copolymer and ethylene-hexene-1 copolymer.
-Ethylene polymers such as olefin copolymers and ethylene-vinyl acetate copolymers, and mixtures thereof. Examples of the α-olefin of the ethylene-α-olefin copolymer include those having 4 to 10 carbon atoms such as butene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, and decene-1. α-olefins. Examples of the propylene-based resin include propylene-based polymers such as polypropylene, propylene-ethylene block copolymer, and propylene-ethylene random copolymer, and mixtures thereof. As the α-olefin of the propylene-ethylene block copolymer and the propylene-ethylene random copolymer, for example, ethylene,
Butene-1 and the like.

When a sealant layer made of a styrene-based resin is used, a container made of a styrene-based resin is used. When a sealant layer made of an ethylene-based resin is used, a container made of an ethylene-based resin or a paper laminated with an ethylene-based resin is used. In the case of a propylene-based resin sealant layer, the propylene-based resin
Each can be used.

There are no particular restrictions on the method for obtaining the laminated film of the present invention.
Conventional co-extrusion processing methods such as co-pressing T-die processing can be used. However, one surface layer is a sealant layer made of at least one resin selected from a styrene resin, an ethylene resin and a propylene resin, and a layer made of the styrene resin composition (X) adjacent to the sealant layer. It is necessary to co-extrude so as to provide

The thickness of the laminated film of the present invention is not particularly limited, but is preferably 20 to 100 μm. The thickness of the sealant layer is not particularly limited, but is preferably 1 to 20 μm.

The laminated film of the present invention comprises the styrene resin composition (X), although there is no particular limitation on the other layers other than the sealant layer and the layer composed of the styrene resin composition (X). Between the sealant layer and the styrenic resin composition (X)
What is necessary is just to be higher than the interlayer adhesive strength of the layer consisting of

The lid material of the present invention comprises the above laminated film. As a method for obtaining the lid material of the present invention, a method of laminating a base material composed of plastic, aluminum foil, paper and the like and the laminated film of the present invention into a laminate, and then processing the laminate into a predetermined shape Is mentioned. Here, it is necessary to laminate the layer on the opposite side of the sealant layer and the substrate. In the case of laminating, it is preferable to apply a surface treatment such as corona treatment to the surface layer of the laminated film and the substrate of the present invention to be laminated, and to laminate the treated surfaces together. When the sealant layer side is heat-sealed to a container (adherend) corresponding to the above-described sealant material, the sealant layer and the adherend are completely fused, and the sealant layer and the styrene-based resin composition ( Peeling occurs between the layers of X) with an appropriate force, and the container can be easily opened.

As a method for obtaining a sealed container, for example, a method of filling the container body with the contents, and then heat-sealing the lid material of the present invention to the container body may be used.

The laminated film of the present invention is, for example,
A bag-shaped container made of the laminated film of the present invention can also be used. In such a case, when the sealant layers of the present invention are heat-sealed, the sealant layers are completely fused to each other, and peeling is performed with an appropriate force between the sealant layer and the layer of the styrene resin composition (X). Can be opened and the bag can be opened.

[0032]

As described in detail above, according to the present invention,
It is possible to provide a laminated film having easy peelability and easy openability, excellent appearance of the peeling interface, and excellent film rigidity. Further, the present invention provides a laminated film which does not use a compatibilizing agent such as a hydrogenated styrene-based compound-conjugated diene-based copolymer or uses a very small amount even if used, and is excellent in cost. it can. Further, the present invention can provide a lid member made of a laminated film having the above excellent physical properties. Further, the present invention provides
A bag-like container made of a laminated film having the above excellent physical properties can be provided.

[0033]

Hereinafter, the present invention will be described based on examples.
The present invention is not limited to these examples.
In addition, among the evaluation items, the items other than the items described above were implemented as follows.

(1) Easy-peeling polyester single-layer film (manufactured by Toyobo Co., Ltd., trade name “Toyobo Ester E5100”, thickness 12 μm, width 50)
0 mm) and a corona-treated surface of the obtained film were dry-laminated. Dry lamination was carried out using a tabletop test coater manufactured by Yasui Seiki Co., Ltd., and an ester anchor coating agent (base agent, manufactured by Takeda Pharmaceutical Co., Ltd., trade name “A969”)
V ", a curing agent, trade name" A5 ", manufactured by Takeda Pharmaceutical Co., Ltd., and ethyl acetate at 29% by weight to 10% by weight, respectively.
Weight percent) and fully mixed)
g / m ^2, and pressed to a film under the conditions of a temperature of 40 ° C. and a pressure of 3 kg / cm ^2.
Heat aging in a dryer at 48 ° C. for 48 hours to obtain a laminated film. The sealant layer side of the obtained laminated film and the adherend were brought into close contact with each other, and the pressure was 3 kg / cm ² , the time was 1 second, and the width was 10 m.
m and heat sealing under the conditions of the temperature shown in Table 1. The following three types were used as adherends. Adherend (1) Rubber-modified polystyrene PS ("Sumibright E580" manufactured by Sumitomo Chemical Co., Ltd.) was extruded to a thickness of 0.1 mm by a V65-1000 sheet extruder manufactured by Tanabe Plastic Machinery Co., Ltd.
A 6 mm sheet was produced. Adherend (2) Low-density polyethylene PE (“Sumikacene L705” manufactured by Sumitomo Chemical Co., Ltd.) was press-molded at a temperature of 140 ° C. to produce a sheet having a thickness of 1 mm. Adherend (3) Homopolypropylene PP (“Sumitomo Noblen Y501N” manufactured by Sumitomo Chemical Co., Ltd.) was press-molded at a temperature of 230 ° C. to produce a sheet having a thickness of 1 mm. And cut using an automatic strain type tensile tester manufactured by Toyo Seiki Co., Ltd.
The peel strength when peeled at 180 ° at a pulling speed of 00 mm / min was measured. This peel strength is 300 g / 15 m
If the width is less than m, the sealing performance in practical use is inferior.
When the width exceeds g / 15 mm, the easy peel property is poor. The stability of the peel strength was determined by determining the difference between the maximum value and the minimum value at each heat sealing temperature. The smaller this value is,
It can be said that the peel strength is stable.

(2) State of Heat Seal Edge Film Remaining and Peeling Surface When peeled in the above evaluation, it was visually observed whether the film was cut at the heat sealing edge or no film residue occurred. Further, the state of the peeled surface was observed. (3) Film rigidity (tensile elastic modulus) The width of the obtained film is 20 m in the MD and TD directions.
Using a sample cut into a strip having a length of 100 mm and a length of 100 mm, a tensile test was performed using a T-type strograph tester manufactured by Toyo Seiki Co., Ltd. under the conditions of a tensile speed of 1 mm / min and a distance between chucks of 60 mm. The tensile modulus was determined by the following equation. Tensile modulus (kg / cm ² ) = (A / (B × C)) ×
(D / E) Here, A: 80% strength of yield strength (kg), B: sample thickness (cm), C: sample width (cm), D: distance between chucks (cm), E: yield strength Elongation at 80% strength (cm).

Example 1 As the component (A) in the styrene resin composition (X), a rubber-modified polystyrene obtained by continuous bulk polymerization (the content of soft component particles: 20.8% by weight, the melt flow rate: 3) .2 g / 10 minutes) as an ethylene-methyl methacrylate copolymer resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: ACLIFT WM403, content of methyl methacrylate unit: 38 weight%) as a component (B). %, SP value: 8.50) of an ethylene-hexene-1 copolymer (melt flow rate: 0.8 g / 10 min, density : 0.925 g / cm
³ ) The pellets of 16% by weight were blended, and pellets of styrene-isoprene block copolymer rubber hydrogenated product (Septon 2104, manufactured by Kuraray Co., Ltd.) were further added as a compatibilizer.
The styrene-based resin composition (X) was added at a ratio of 4 parts by weight to 100 parts by weight and mixed well, and the mixture was heated to a temperature of 210 ° C. using a 40 mmφ single screw extruder manufactured by Tanabe Plastic Machinery Co., Ltd. And pelletized. As the resin constituting the sealant layer, rubber-modified polystyrene obtained by continuous bulk polymerization (the content of soft component particles: 20.8% by weight, the melt flow rate: 3.2 g /
10 minutes). Using the above materials, a cast film forming apparatus manufactured by Modern Machinery Co., Ltd. (three types and three layers co-pressing T-die (width: 600 mm, extruder A: 40 mmφ,
Extruder B: 50 mmφ, extruder C: 40 mmφ)), and extruding the styrene resin composition (X) into extruders B and C.
Resin temperature 240 ° C, extrusion rate 10kg / hour and 8
The extruder A extrudes the resin constituting the sealant layer at a resin temperature of 240 ° C. and an extrusion rate of 4 kg / hour.
The two-layer laminated film was extruded under the conditions of time, a take-up speed of 12.4 m / min, and a cooling roll temperature of 40 ° C., and the layer side of the film made of the styrene resin composition (X) was further subjected to wet tension. Corona treatment was performed so as to be 45 dyne / cm. The thickness of the sealant layer of the obtained film was 8 μm, and the overall thickness was 44 μm. Table 1 shows the results
Shown in

Example 2 The same styrenic resin composition (X) as in Example 1 was used, and the resin constituting the sealant layer was polystyrene obtained by continuous bulk polymerization (weight average molecular weight: 300,000; (Melt flow rate: 4 g / 10 min) was used. Modern Machinery Co., Ltd. Cast Film Casting Equipment (3 types, 3 layers co-press T-die (width: 600mm,
Extruder A: 40 mmφ, extruder B: 50 mmφ, extruder C: 40 mmφ)), the styrene-based resin composition (X) was extruded with extruders B and C at a resin temperature of 250 ° C., an extrusion rate of 10 kg / h and 8 kg / h. The resin constituting the sealant layer was extruded under the conditions of
The two-layer laminated film was extruded at a temperature of 30 ° C. and an extrusion rate of 4 kg / hour, a take-up speed of 15.5 m / min, and a cooling roll temperature of 40 ° C., and further processed from the styrene resin composition (X) of the film. Layer side with a wetting tension of 45 dyn
Corona treatment was performed so as to obtain e / cm. The thickness of the sealant layer of the obtained film is 8 μm, and the total thickness is 44 μm.
m. Table 1 shows the results.

Example 3 The same styrene resin composition (X) as in Example 1 was used, and the resin constituting the sealant layer was polyethylene (melt flow rate: 8.0 g / 10 min, density:
0.938 g / cm ³ ) pellets were used. As the third layer, rubber-modified polystyrene (soft component particle content: 20.8% by weight, melt flow rate: 3.2 g / 10 minutes) pellets 20% by weight obtained by continuous bulk polymerization, high pressure ion Ethylene-hexene-1 copolymer (melt flow rate:
0.8 g / 10 min, density: 0.925 g / cm ³ ) 70% by weight of pellets and styrene-isoprene block copolymer rubber hydrogenated product (trade name “Septon 2104” manufactured by Kuraray Co., Ltd.) % By weight and sufficiently mixed, and this was granulated at 210 ° C. using a 40 mmφ extruder manufactured by Tanabe Plastic Machinery Co., Ltd. to form pellets (resin (Y)). Using the above-mentioned materials, a cast film forming apparatus manufactured by Modern Machinery Co., Ltd. (three types and three layers co-pressing T-die (width: 600 mm, extruder A: 40 mmφ, extruder B: 50 mmφ, extruder C: 40 mmφ)) Extruding the styrene resin composition (X) with an extruder B at a resin temperature of 230 ° C. and an extrusion rate of 13 kg / hour;
The resin (Y) is extruded by an extruder C at a resin temperature of 230 ° C. and an extrusion rate of 5 kg / hour, and the resin constituting the sealant layer is extruded by an extruder A at a resin temperature of 200 ° C. and an extrusion rate of 4 kg.
Resin / (Y) / styrene-based resin composition (X) /
The three-layer laminated film laminated in the order of the sealant layer was processed, and the layer side made of the resin (Y) of the film was subjected to corona treatment so as to have a wetting tension of 45 dyne / cm. The thickness of the sealant layer of the obtained film was 8 μm, and the overall thickness was 44 μm. Table 1 shows the results.

Example 4 The same effect can be obtained by performing the same operation as in Example 4 using a propylene-based resin as the resin constituting the sealant layer.

Comparative Example 1 A styrene-butadiene block copolymer rubber ("Tuffrene A", manufactured by Asahi Kasei Corporation, weight ratio of styrene units to butadiene units = 40/60) was used as the component (B). Using a pellet obtained in the same manner as in Example 1, a single-layer inflation processing machine manufactured by Tommy Corporation (extruder: 50 m
Under the conditions of mφ, die diameter 120 mm, lip opening 1.2 mm), a single layer film having a folded width of 450 mm and a thickness of 45 μm is processed, and the outside of the film is wetted with a tension of 45 dy.
Corona treatment was performed so as to obtain ne / cm. Table 1 shows the results.

[0041]

Table 1--------------------------------------------------------------------------------------------------------------------Example −−−−−−−−−−−−−−−−−−−−−− Easy peelability Peel strength g / 15mm width Substrate PS PS PE PS Heat seal temperature 150 ℃ g / 15mm width 800 570 − 1080 160 ° C g / 15mm width 770 600 − 1220 170 ° C g / 15mm width 820 630 520 1380 180 ° C g / 15mm width 830 670 510 1450 190 ° C g / 15mm width − − 590 − 200 ° C g / 15mm width − − 570 − Difference between maximum and minimum values 60 100 80 370 Seal edge film remaining No No No-Peeling surface state ○ ○ ○ × Film rigidity kg / cm ² MD 11300 11200 10500 10000 TD 6100 5900 7100 5000 −−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 25/04 C08L 25/04 // B65D 77/20 B65D 77/20 H

Claims (12)

[Claims] 1. A laminated film comprising at least two layers, wherein one surface layer is a sealant layer made of at least one resin selected from styrene-based resins, ethylene-based resins and propylene-based resins. A layer comprising the following styrenic resin composition (X) adjacent to the laminated film. A styrene-based resin composition (X) containing 40 to 80% by weight of the following component (A);
A styrenic resin composition containing (B) component 20 to 60% by weight and (C) component 0 to 40% by weight. (A) component: styrene resin (B) component: solubility parameter (SP) is 8.45 to
Olefinic resin which is 8.70 and does not contain a repeating unit derived from an aromatic vinyl compound in the polymer (C) component: an olefinic resin other than the (B) component (2) The component (B) comprises ethylene and a repeating unit derived from one or more vinyl monomers selected from unsaturated carboxylic acids, unsaturated carboxylic esters, unsaturated carboxylic anhydrides and vinyl acetate. 2. An ethylene copolymer comprising a derived repeating unit.
The laminated film according to the above. 3. The laminated film according to claim 2, wherein the component (B) is an ethylene-unsaturated carboxylic acid ester copolymer. 4. The laminated film according to claim 2, wherein the component (B) is an ethylene-methyl methacrylate copolymer or an ethylene-vinyl acetate copolymer. 5. The laminated film according to claim 4, wherein the component (B) is an ethylene-methyl methacrylate copolymer having a content of a repeating unit derived from methyl methacrylate of 15 to 50% by weight. 6. Component (C) has a temperature of 190 ° C. and a load of 2.1.
The laminated film according to claim 1, which is a polyethylene, an ethylene-α-olefin copolymer or a mixture thereof, having a melt flow rate of 0.2 to 10 g / 10 minutes measured according to JIS K7210 under a condition of 6 kg. . 7. Component (C) has a temperature of 230 ° C. and a load of 2.1.
A polypropylene, a propylene-α-olefin block copolymer, a propylene-α-olefin random copolymer or a propylene-α-olefin block copolymer having a melt flow rate of 0.2 to 10 g / 10 minutes measured according to JIS K7210 under a condition of 6 kg. The laminated film according to claim 1, which is a mixture of: 8. The method according to claim 1, wherein 100 parts by weight of the styrene resin composition (X) further contains 0.5 to 5 parts by weight of a hydrogenated styrene compound / conjugated diene copolymer. Laminated film. 9. The water of a styrene-isoprene block copolymer rubber in which the hydrogenated styrene-based compound-conjugated diene-based copolymer has a content of a repeating unit derived from styrene of 30 to 80% by weight. Additive or styrene
9. The laminated film according to claim 8, which is a hydrogenated product of a butadiene block copolymer rubber. 10. The laminated film according to claim 1, wherein the thickness of the sealant layer is 1 to 20 μm. 11. A lid comprising the laminated film according to any one of claims 1 to 10. 12. A bag-like container comprising the laminated film according to any one of claims 1 to 10.