JP2002301786A - Coextrusion multilayered film and lid material of container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coextrusion multilayered film generating no stickiness caused by a pressure-sensitive adhesive, excellent in workability and enabling perfect sealing and re-sealing, and the lid material of a container comprising the same. SOLUTION: The coextrusion multilayered film is constituted by stacking a surface resin layer (A) containing a thermoplastic resin (a), a pressure-sensitive adhesive resin layer (B) containing a rubbery thermoplastic resin (b1) and a pressure-sensitive adhesive (b2) and a heat-sealing resin layer (C) containing a thermoplastic resin (c) in the order of (A)/(B)/(C) and characterized by that the interlaminar strength of the layer (B) and the layer (C) is 20-20 N/15 mm, or less than that of the layer (A) and the layer (B), and the thickness of the layer (C) is 0.5-10 μm. The lid material of the container comprising the film is also disclosed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coextruded multilayer film having adhesiveness and a lid material for a container using the same.

[0002]

2. Description of the Related Art Adhesive type surface protection films based on olefin resins such as polyethylene and polypropylene are generally used because they have water resistance and do not generate toxic gas even after incineration after use. . As a method for producing an adhesive film having an olefin-based resin as a base material, for example, by co-extruding an adhesive layer and an olefin-based resin base layer as described in JP-B-61-103975. There is a multi-layer technology.

[0003] In a protective film that holds an adhesive layer directly on an olefin-based resin substrate film, since the adhesive layer is disposed directly outside, when the film is rolled up, the films adhere to each other, or a guide roll or a roll is wound up. Problems such as adhesion to the take-up roll have occurred. In addition, when the rigidity is low or the thickness of the base material is thin, wrinkles are easily formed, and the winding operation becomes difficult. Therefore, as the olefin-based resin base material, use a high-rigidity resin or a thick base film. There was no choice but to use it, and there were also restrictions on the film construction surface and thinning.

As a method of solving such a problem, the stickiness of the film is eliminated by adding a release agent to the surface opposite to the adhesive surface, or by laminating release paper at the time of film formation or application of the adhesive. Workability at the time of winding and slitting is ensured by adopting a configuration or increasing the thickness of the base film.

[0005] However, the roll directly in contact with the adhesive surface is
Special release processing such as silicon roll and embossing needs to be performed, so a special specification film formation line is required, and workability is poor, so there is a restriction that extrusion speed and coating speed cannot be increased. Was. Furthermore, since an additive such as a release agent is compounded in the film on the side opposite to the adhesive surface, there are restrictions when using food. In addition, since the release agent or the adhesive directly touches the contents, there is a possibility that the additives and their odor may be transferred to the contents, and there is a limitation on the use of food and the like in terms of safety and hygiene. .

A conventional protective film for holding an adhesive layer simply retains tackiness by the adhesive force of an adhesive formed on a surface layer, and is not completely sealed. Therefore, it was poor in airtightness and could not be used for gas replacement packaging or liquid packaging.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a co-extruded multilayer film which has no stickiness due to an adhesive, is excellent in workability, can be completely sealed, and can be resealed (resealed). And a cover material for a container made of a co-extruded multilayer film.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a surface resin layer (A) containing a thermoplastic resin (a), a rubbery thermoplastic resin (b1) and a tackifier are provided. Pressure-sensitive resin layer (B) containing agent (b2) and heat-sealing resin layer (C) containing thermoplastic resin (c)
Is a co-extruded multilayer film laminated in the order of (A) / (B) / (C), and has an interlayer adhesive strength (JIS Z-) between the pressure-sensitive adhesive resin layer (B) and the heat sealing resin layer (C). 17
Strength measured at a tensile speed of 300 mm / min in accordance with Standard No. 07. The same applies hereinafter. ) Is 2 to 20 N / 15 mm, and
The co-extruded multilayer film having a lower interlayer adhesion strength between the surface resin layer (A) and the adhesive resin layer (B) and a thickness of the heat-seal resin layer (C) of 0.5 to 10 μm is an adhesive resin layer. Since (B) is sandwiched between the surface resin layer (A) and the heat sealing resin layer (C), there is no stickiness at the time of film production, and it can be formed by a conventional heat-melt extrusion line and has excellent workability. Since it has a heat seal resin layer (C), complete sealing is possible, and the interlayer adhesion strength between the adhesive resin layer (B) and the heat seal resin layer (C) and the thickness of the heat seal resin layer (C) are controlled. Therefore, it has an easy-opening property, and when the heat-sealing resin layer (C) is broken at the time of opening, the layer between the heat-sealing resin layer (C) and the pressure-sensitive adhesive layer (B) is easily peeled off. Since (B) appears on the surface, reseal ( That seal) is possible,
For this reason, this co-extruded multilayer film can be used as it is, or can be suitably used as a lid material for various containers by laminating a stretched substrate or the like, or can be molded as it is as a container, or The inventors have found that they can be suitably used as a container after being molded after being laminated on a sheet, and have completed the present invention.

That is, the present invention relates to a surface resin layer (A) containing a thermoplastic resin (a), an adhesive containing a rubbery thermoplastic resin (b1) and a tackifier (b2). A co-extruded multilayer film in which a resin layer (B) and a heat sealing resin layer (C) containing a thermoplastic resin (c) are laminated in the order of (A) / (B) / (C). The interlayer adhesive strength between the adhesive resin layer (B) and the heat sealing resin layer (C) is 2 to 20 N / 15 mm, and the surface resin layer (A)
And the adhesive strength of the adhesive resin layer (B) is smaller than the interlayer adhesive strength, and the thickness of the heat seal resin layer (C) is 0.5 to 10 μm.
m, wherein a co-extruded multilayer film is provided.

[0010] The present invention also provides a lid material for a container comprising the co-extruded multilayer film.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The surface resin layer (A) may be a resin layer containing a thermoplastic resin (a) as a main component, and may be a single-layer resin layer or a multi-layer resin layer. . The thermoplastic resin (a) used here includes olefin resins such as ethylene resins and propylene resins, styrene resins, ester resins, amide resins, imide resins, and ethylene-vinyl acetate copolymer ketones. And a mixture of two or more of them, which is used for a single layer structure or a multilayer structure. For example, as the thermoplastic resin (a), a styrene resin, an ester resin,
Resins that have excellent physical properties such as rigidity and gas barrier properties, but have poor adhesion to the adhesive resin layer (B), such as amide resins, imide resins, and saponified resins of ethylene-vinyl acetate copolymer. When used, the surface resin layer (A) is in contact with a layer made of such a resin and has an olefin-based adhesive resin or the like on the side of the adhesive resin layer (B) for the purpose of improving adhesiveness with the adhesive resin layer (B). It is preferable to have a multilayer structure provided with an adhesive layer made of

[0012] Examples of the ethylene resin include very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). -Based resin; ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene- Ethylene copolymers such as ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA); Ionomer of acrylic acid copolymer, ethylene-methacrylic Ionomer of an acid copolymer,
Among these, low-density polyethylene (LDPE) is preferable because it has little film residue at the time of opening and has good releasability.

Examples of the propylene-based resin include propylene homopolymers and copolymers of propylene with other α-olefins such as ethylene and butene. The copolymers include random copolymers and block copolymers. Any of the polymers can be used. As propylene homopolymer,
Examples include isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene. Of these, isotactic polypropylene is preferable.

As these thermoplastic resins (a), olefin resins such as ethylene resins and propylene resins are preferable because they are inexpensive and have excellent moldability. Among them, linear low density polyethylene (LLDPE), Particularly preferred are density polyethylene (LDPE), propylene homopolymer, and copolymers of propylene with other α-olefins.

Further, as the olefin-based adhesive resin, an acid-modified olefin-based resin obtained by grafting at least one monomer selected from unsaturated carboxylic acids or derivatives thereof is preferable.

Further, the surface resin layer (A) may contain, if necessary, an antifogging agent, an antistatic agent, a heat stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, an ultraviolet absorber and the like. Components may be added within a range that does not impair the purpose of the present invention.

The adhesive resin layer (B) may be any resin layer containing a rubbery thermoplastic resin (b1) and a tackifier (b2), as long as it has adhesiveness. As the rubbery thermoplastic resin (b1) used here,
It is not particularly limited as long as it is a thermoplastic resin having a rubbery property, and for example, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butadiene -Styrene block copolymer (SEB
S), styrene-ethylene-propylene-styrene block copolymer (SEPS), hydrogenated styrene-butadiene block copolymer (HSBR), styrene-butadiene block copolymer (SB), styrene-isoprene block copolymer Combined (SI), styrene-ethylene-
Propylene block copolymer (SEP), styrene-butadiene-butylene-styrene block copolymer (SB
BS) and other rubbery block copolymers containing styrene blocks; ethylene-propylene copolymers (E
P), ethylene such as ethylene-butene-1 copolymer (EB), ethylene-octene copolymer (EO), propylene-butadiene copolymer (PB), ethylene-vinyl acetate copolymer (EVA), etc. And rubbery copolymers obtained as an essential component, among which styrene-
Butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SI
S), hydrogenated styrene-butadiene block copolymer (HSBR), ethylene-vinyl acetate copolymer (E
VA) is preferred.

Examples of the tackifier (b2) include resins having tackiness at room temperature, such as natural resins and synthetic resins, such as natural resin rosin, polymerized rosin, hydrogenated rosin, glycerene sterrosin, and pentane. Rosin resins such as erythritol; terpene resins such as terpene, aromatic modified terpene, terpene phenol, hydrogenated terpene; petroleum resins such as aliphatic petroleum resin, aromatic petroleum resin, hydrogenated alicyclic petroleum resin A liquid polybutadiene at room temperature, a polyisoprene liquid at room temperature, a polyisobutylene liquid at room temperature, among others, rosin-based resins,
Terpene resins and petroleum resins are preferred.

The mixing ratio of the rubbery thermoplastic resin (b1) and the tackifier (b2) is such that the rubbery thermoplastic resin (b1) has a good balance between the adhesive effect and the extrusion processability.
50-98% by weight and the weight ratio of the tackifier (b2) (b1
/ B2) is preferably in the range of 50/50 to 98/2, and particularly preferably in the range of 60/40 to 90/10.

The adhesive resin layer (B) may contain various additives such as a softener, an oil (mineral oil),
Stabilizers (antioxidants and the like) may be added.

The above surface resin layer (A) and adhesive resin layer (B)
It is necessary that the bonding strength between these layers be a good combination in which the bonding strength between the pressure-sensitive adhesive resin layer (B) and the heat-sealing resin layer (C) is greater than 2 to 20 N / 15 mm. . As a combination of the surface resin layer (A) and the adhesive resin layer (B) satisfying such conditions, for example, styrene-
Butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SI
S), a hydrogenated product of a styrene-butadiene block copolymer (HSBR), and at least one rubbery copolymer selected from the group consisting of an ethylene-vinyl acetate copolymer (EVA), and a rosin-based resin. When a resin layer comprising a tackifier comprising at least one resin selected from the group consisting of a terpene resin and a petroleum resin is used, an olefin having good adhesion to the adhesive resin layer is formed on the adhesive resin layer. A single-layer resin layer composed of a base resin is converted to a surface resin layer (A).
Or a resin having relatively poor adhesion to the adhesive resin layer, such as a styrene-based resin, an ester-based resin, an amide-based resin, an imide-based resin, and a saponified resin of an ethylene-vinyl acetate copolymer. A resin layer having a multi-layer structure consisting of a layer (surface side) composed of the following and an adhesive layer (a side in contact with the adhesive resin layer (B)) composed of an olefin-based adhesive resin or the like is defined as a surface resin layer (A). Examples include the combination used.

The heat-sealing resin layer (C) is a resin layer containing a thermoplastic resin (c) as a main component and capable of sheet sealing, and has an interlayer adhesive strength of 2 to the pressure-sensitive adhesive resin layer (B). It is necessary that the resin layer has a thickness of 20 N / 15 mm and is smaller than the interlayer adhesive strength between the surface resin layer (A) and the adhesive resin layer (B).

Examples of the thermoplastic resin (c) used herein include olefin resins such as ethylene resins and propylene resins, and styrene resins. Examples of the ethylene resins and propylene resins include thermoplastic resins. As the resin (a), any of the above-mentioned ethylene-based resins and propylene-based resins can be used, and they can be used alone or in combination of two or more.

As the thermoplastic resin (c), it is preferable to use an olefin resin such as an ethylene resin or a propylene resin because it is inexpensive and has excellent molding performance and sealing suitability. Heat sealability,
Ethylene resins are more preferred because of their excellent sealing properties and the like, and low density polyethylene having a density of 0.90 to 0.93 g / cm3 is particularly preferred. In addition, since the ethylene-based resin is excellent in adhesion between the container and the lid material, stability of the sealing strength, and the like, the temperature is 190 ° C. in accordance with JIS K-7210.
(Melt index) of 5 to 80 g /
Preferably, the time is 10 minutes.

Further, it is indispensable for a packaging material having a reseal function to be able to determine that the package has been opened. In other words, if a packaging material having a resealing function is used, there is a risk that once opened, it is resealed and displayed and sold. It is effective to add a filler to the heat-sealing resin layer (C) in order to leave a trace of opening, which is a function of preventing tampering. As the filler, an inorganic material such as calcium carbonate or talc is preferable because the price and the trace state become clear.

Further, in the heat seal resin layer (C),
If necessary, an antifogging agent, an antistatic agent, a heat stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, an ultraviolet absorber and the like may be added as long as the object of the present invention is not impaired. good.

A preferable combination of the layers of the co-extruded multilayer film of the present invention is, for example, a surface resin layer using an olefin resin such as an ethylene resin or a propylene resin as the thermoplastic resin (a). (A) and an adhesive resin layer (B) using a rubbery block copolymer containing a styrene block as a rubbery thermoplastic resin (b1) or a rubbery copolymer obtained by using ethylene as an essential component; Examples of the thermoplastic resin (c) include a combination of a heat seal resin layer (C) using an olefin resin such as an ethylene resin or a propylene resin. Among them, styrene-based rubbery thermoplastic resin (b1) is used. Butadiene-styrene block copolymer (SB
S), selected from the group consisting of styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-butadiene block copolymer (HSBR), and ethylene-vinyl acetate copolymer (EVA) A combination using at least one kind of rubbery copolymer, a combination using a propylene-based resin as the thermoplastic resin (a), and a low-density polyethylene as the thermoplastic resin (c), and a tackifier (b2) A combination using a tackifier comprising at least one resin selected from the group consisting of rosin-based resins, terpene-based resins and petroleum resins is particularly preferred.

In the co-extruded multilayer film of the present invention, the interlayer adhesive strength of each resin layer largely depends on the adhesiveness between the resin layers. It is important to appropriately select the above, but in this case, it is necessary to consider that the interlayer adhesive strength also changes depending on the thickness of the resin layer. Even if the pressure-sensitive adhesive resin layer (B) and the heat-sealing resin layer (C) are used in a combination having relatively excellent adhesion, for example, in the case of a heat-sealing resin layer made of low-density polyethylene, the thickness is 0.3 If it is as small as ~ 1 µm, the interlayer adhesive strength is greatly reduced, and if it is as large as 20 ~ 30 µm, the interlayer adhesive strength is a large value without decreasing.

As a method for producing a co-extruded multilayer film of the present invention, for example, three or more extruders are used for melt extrusion and lamination in a molten state by a known method such as a co-extruded multilayer die method or a feed block method. Later, inflation and T
A method of forming a multilayer film by a die-chill roll method or the like may be used. In addition, in order to improve the adhesiveness of printing and the suitability for lamination, it is desirable to apply a surface treatment to the surface resin layer (A).

Examples of the surface treatment include corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, surface oxidation treatment such as ozone / ultraviolet treatment, and surface unevenness treatment such as sand blast. It is.

The co-extruded multilayer film of the present invention has no tackiness on the film surface because the adhesive resin layer (B) is sandwiched between the surface resin layer (A) and the heat-sealing resin layer (C). Handling at the time of slitting or slitting is the same as that of a conventional film, and handling is good. In contrast, the conventional film has a pressure-sensitive adhesive directly added to the surface of the pressure-sensitive adhesive resin layer, and the film itself has self-adhesiveness, so that it is difficult to handle, and furthermore, the adhesive force due to its adhesive strength.
Although the adhesiveness was developed to maintain the strength with the adherend, the strength was due to the adhesive force of the adhesive itself, so that the strength was weak and the seal was not completely sealed. In the case of a packaging material configuration that requires oxygen barrier properties, for example, when gas replacement packaging is performed for the purpose of deoxidation, if it is not a complete seal, oxygen and nitrogen in the atmosphere enter from the sealing surface, and the quality of the package contents will deteriorate. There was a risk of occurrence and use was not possible. In addition, when the content is a liquid, there is also a risk of leakage from the seal portion.

Conventionally, a film having a structure such as paper / aluminum / hot melt is used for a lid material for instant food such as a ramen cup, but such a structure is easy to open. This is because it has an easy-opening function and keeps the lid turned up when pouring hot water by using the plastic deformation characteristics of aluminum, and keeps the lid closed before opening during cooking time. However, when using thin aluminum or a film without aluminum,
In some cases, the plastic deformability cannot be maintained and does not return to the original state, and the lid is closed with a weight that changes during the cooking time. In addition, there is a strong demand for suppressing the use of aluminum because it is difficult to reduce environmental load and separate and collect in recent years. However, there is no material having plastic deformation performance equivalent to that of aluminum, and it is difficult to find a material that can easily maintain a resealed state during cooking.

However, the co-extruded multilayer film of the present invention
Since heat sealing is performed by heat melting of the heat sealing resin layer, leakage of the replacement gas and the liquid is improved. Moreover, the co-extruded multilayer film of the present invention has an interlayer adhesive strength between the pressure-sensitive adhesive resin layer (B) and the heat-sealing resin layer (C) of 2 to 20 N / 15 m.
m is smaller than the interlayer adhesive strength between the surface resin layer (A) and the adhesive resin layer (B), and the heat seal resin layer (C)
Has a thickness of as small as 0.5 to 10 μm, so that it can be easily opened (easy to be opened), and the peeled surface at the time of unsealing does not have a rough surface and does not have a film.
At the time of opening, the heat seal resin layer (C) is easily broken,
Next, the interlayer between the heat-sealing resin layer (C) and the adhesive resin layer (B) is easily peeled off, the adhesive resin layer (B) appears on the surface, and resealing (resealing) by adhesion becomes possible.

When such a co-extruded multilayer film of the present invention is used for an instant food lid such as a ramen cup,
Opening has an easy easy-opening function, and at the same time, it is possible to hold the lid before opening during the cooking time,
It is a material that can replace the plastic deformation performance of aluminum. Also,
The use of the co-extruded multilayer film of the present invention makes it possible to provide a dealuminized film which has been strongly demanded for a long time, thereby contributing to a reduction in environmental load. When the co-extruded multilayer film of the present invention is used for a lid material, it can be used as a laminated film by laminating with a base film as described below.

The interlayer adhesive strength of the adhesive resin layer (B) and the heat seal resin layer (C) of the co-extruded multilayer film of the present invention is preferably 4 to 15 N / 15 mm. The thickness of the layer (C) is preferably 1 to 10 μm,
Those having a thickness of 1 to 6 μm are particularly preferred.

Further, a base film may be laminated on the surface resin layer (A) of the co-extruded multilayer film of the present invention via an adhesive resin or an adhesive to form a laminate film. Examples of the base film include biaxially oriented polypropylene (OPP), biaxially oriented nylon (ONY), biaxially oriented polyethylene terephthalate (PET), aluminum (AL), paper, nonwoven fabric, and the like. It is not limited. Examples of the bonding method include wet lamination, non-solvent lamination, dry lamination, and extrusion lamination.

As an adhesive for dry lamination,
For example, polyester-polyurethane-based adhesives, polyether-polyurethane-based adhesives and the like can be mentioned.

As described above, the co-extruded multilayer film of the present invention and the laminated film obtained by laminating the film and the laminated base material have the airtightness and practical strength obtained by heating and melting the heat seal resin layer (C). In addition to being able to be a heat seal, the peeled surface after opening can be resealed (resealed) by the adhesive function because the adhesive resin layer is exposed on the surface, so it is suitable for various containers and lid materials thereof Can be used for For example, if the thickness is 50 to 200
μm can be used as a cover material for various containers as
Those having a thickness of 0 to 100 μm are laminated with a stretched base material or the like to form lids for various containers. Similarly, those having a thickness of 20 to 100 μm are formed by laminating a base sheet and then molded to form a container having a thickness of 200 to 500 μm. These are molded as they are and are suitable as containers. Among them, it is particularly preferable to use a material having a thickness of 50 to 200 μm as it is, or a material having a thickness of 20 to 100 μm, which is laminated with a stretched substrate or the like, and use them as lids for various containers.

Examples of the container using the lid material comprising the co-extruded multilayer film of the present invention include styrene resin, expanded styrene resin, propylene resin, ester resin, etc. by injection molding, vacuum molding, air pressure molding and the like. Cups and trays manufactured by a molding method, and paper cups and paper trays formed by laminating an olefin-based resin such as polyethylene on paper, and the like are included. These containers have a heat seal portion with the lid material, for example, a flange-shaped heat seal, and select the type of the heat seal resin of the lid material according to the type of resin in this portion, and increase the sealing strength. Can be adjusted.

Examples of such containers include instant noodle containers, jelly containers, yogurt containers, confectionery containers, marine products containers, processed animal products containers, and the like.

Among such containers, particularly, instant noodles containers for instant foods that are resealed during cooking, and tastes that cannot be eaten at a time, and are eaten after opening for a while.
Strong fashion snacks, containers of chocolate confectionery, etc., meat and meat products containers such as sliced ham, which are too many and used as food ingredients in several times, use the lid material made of the co-extruded multilayer film of the present invention. It is suitable as a container.

[0042]

Next, the present invention will be described in detail with reference to examples. Example 1 As a surface resin layer (A), a propylene homopolymer (HOPP) having a density of 0.90 g / cm ³ was coated on an adhesive resin layer (B).
Styrene-butadiene-styrene block copolymer (SBS) 60 parts by weight, terpene resin [Yasuhara Chemical Co., Ltd. terpene resin, YS resin PX115
0] 38.5 parts by weight, 0.5 part by weight of a phenolic antioxidant, and 1 part by weight of liquid paraffin were uniformly mixed with a twin-screw extruder to form a pelletized resin having a density of 0 as a sealing resin layer (C). .92 g / cm ³ of low-density polyethylene (LDPE) was extruded with a (A) layer extruder (50 mm diameter),
(B) Layer extruder (50 mm diameter), (C) Layer extruder (40 mm diameter), and each extruder of a co-extruded multilayer film manufacturing apparatus of a T-die / chill roll method having a feed block. The co-melt extrusion was performed at a temperature of 230 ° C., and the average thickness of each layer was 15
A co-extruded multilayer film (1) having a thickness of 50 μm / 30 μm / 5 μm and a total thickness of 50 μm was obtained. The interlayer adhesion strength between the surface resin layer (A) and the adhesive resin layer (B) of the obtained co-extruded multilayer film (1) is 20 N / 15 mm, and the interlayer adhesion between the adhesive resin layer (B) and the heat seal resin (C). Strength is 15N / 15m
m.

Next, a laminate film (I) is obtained by laminating a biaxially stretched polyethylene terephthalate base material (thickness: 12 μm) on the surface resin layer (A) side of the obtained co-extruded multilayer film (1) by dry lamination. Was.

Comparative Example 1 The average thickness of the three layers A / B / C was 15 μm / 34.6 μm
A co-extruded multilayer film (1 ′) having an overall film thickness of 50 μm was obtained in the same manner as in Example 1 except that the thickness was changed to /0.4 μm. Obtained co-extruded multilayer film (1 ')
The interlayer adhesive strength between the surface resin layer (A) and the adhesive resin layer (B) was 20 N / 15 mm, and the interlayer adhesive strength between the adhesive resin layer (B) and the heat seal resin (C) was 1 N / 15 mm.

Next, a laminated film (I ') obtained by laminating a biaxially stretched polyethylene terephthalate substrate was obtained in the same manner as in Example 1 except that the obtained co-extruded multilayer film (1') was used.

Example 2 A linear low-density polyethylene (LLDPE) having a density of 0.92 g / cm ³ was used as the surface resin layer (A), and an ethylene-vinyl acetate copolymer (EV) was used as the adhesive resin layer (B).
A) 60 parts by weight, 39.5 parts by weight of a petroleum resin (hydrogenated petroleum resin manufactured by Arakawa Chemical Co., Ltd., Alcon P-125) and 0.5 part by weight of a phenolic antioxidant are uniformly mixed with a twin-screw extruder. The resin mixed and pelletized was used as a heat seal resin layer (C) having an ethylene content of 3% by weight and a density of 0.90 g.
/ Cm ³ propylene-polyethylene copolymer (COP
In the same manner as in Example 1 except that each of P) was used, a three-layer structure of A / B / C was used, and the average thickness of each layer was 15 μm.
A co-extruded multilayer film (2) having m / 30 μm / 5 μm and a total thickness of 50 μm was obtained. The interlayer adhesion strength between the surface resin layer (A) and the adhesive resin layer (B) of the obtained co-extruded multilayer film (2) is 20 N / 15 mm, and the interlayer adhesion between the adhesive resin layer (B) and the heat seal resin (C). Strength is 15N / 15mm
Met.

Next, a paper substrate (basis weight 80 g / g) was placed on the surface resin layer (A) of the obtained co-extruded multilayer film (2).
cm ² ) with low density polyethylene (LDP) for lamination
E) Extrusion lamination by melt extrusion at 300 ° C. (MI = 20 g / min) was performed to obtain a bonded laminated film (II).

Comparative Example 2 The average thickness of the three layers A / B / C was 15 μm / 5 μm / 25.
A coextruded multilayer film (2 ′) having a total film thickness of 50 μm was obtained in the same manner as in Example 2 except that the thickness was changed to μm. The interlayer adhesive strength between the surface resin layer (A) and the adhesive resin layer (B) of the obtained co-extruded multilayer film (2 ') is 15 N / 1.
5 mm, adhesive resin layer (B) and heat seal resin (C)
Was 25 N / 15 mm.

Next, a laminated film (II ') having a paper substrate laminated thereon was obtained in the same manner as in Example 2 except that the obtained co-extruded multilayer film (2') was used.

Comparative Example 3 As a surface resin layer (A), a propylene homopolymer (HOPP) having a density of 0.90 g / cm ³ was coated with an adhesive resin layer (B).
As ethylene-vinyl acetate copolymer (EVA) 60
The same co-extruded multilayer film manufacturing apparatus as in Example 1 was obtained by uniformly mixing and pelletizing parts by weight of a resin, 38 parts by weight of petroleum resin, 1 part by weight of phenolic antioxidant, and 1 part by weight of liquid paraffin with a twin-screw extruder. (A) layer extruder (caliper 5
0 mm) and (B) are supplied to a layer extruder (50 mm in diameter), respectively, and are co-melt extruded at a temperature of 230 ° C. The two layers A / B have an average thickness of 45 μm / 5 μm and an overall thickness of To obtain a co-extruded multilayer film (3 ′) having a thickness of 50 μm.
The interlayer adhesion strength between the surface resin layer (A) and the adhesive resin layer (B) of the obtained co-extruded multilayer film (3 ') is 10 N / 1.
5 mm.

Next, PET was carried out in the same manner as in Example 1 except that the obtained co-extruded multilayer film (3 ') was used.
A laminate film (III ') on which the substrates were bonded was obtained.

Example 3 As a surface resin layer (A), a propylene homopolymer (HOPP) having a density of 0.90 g / cm ³ was coated with an adhesive resin layer (B).
Styrene-butadiene block copolymer hydrogenated product (HSBR) 60 parts by weight, terpene resin [Yasuhara Chemical Co., Ltd. terpene resin, YS resin PX11
50] 38.5 parts by weight, phenolic antioxidant 0.5
Part by weight and 1 part by weight of liquid paraffin are uniformly mixed with a twin-screw extruder, and the pelletized resin is sealed with a sealing resin layer (C).
In the same manner as in Example 1 except that low-density polyethylene (LDPE) having a density of 0.92 g / cm ³ was used, a three-layer structure of A / B / C was used, and the average thickness of each layer was 15 μm / A co-extruded multilayer film (3) having a thickness of 30 μm / 5 μm and a total thickness of 50 μm was obtained. The interlayer adhesion strength between the surface resin layer (A) and the adhesive resin layer (B) of the obtained co-extruded multilayer film (3) is 20 N / 15 mm, and the adhesive resin layer (B)
And the heat-sealing resin (C) have an interlayer adhesion strength of 10N / 1
5 mm.

Next, a paper base (80 g / basis weight) was placed on the surface resin layer (A) of the obtained co-extruded multilayer film (3).
cm ² ) with low density polyethylene (LDP) for lamination
E) Extrusion lamination by melt extrusion at 300 ° C. (MI = 20 g / min) was performed to obtain a laminated film (III) that was laminated.

Example 4 As a surface resin layer (A), a propylene homopolymer (HOPP) having a density of 0.90 g / cm ³ was coated with an adhesive resin layer (B).
Styrene-isoprene-styrene block copolymer (SIS) 60 parts by weight, terpene resin [Yasuhara Chemical Co., Ltd. terpene resin, YS resin PX115]
0] 38.5 parts by weight, 0.5 part by weight of a phenolic antioxidant, and 1 part by weight of liquid paraffin were uniformly mixed with a twin-screw extruder to form a pelletized resin having a density of 0 as a sealing resin layer (C). In the same manner as in Example 1 except that a low-density polyethylene (LDPE) of .92 g / cm ³ was used, the average thickness of each layer was 15 μm / 30 μm / 5 μm. A co-extruded multilayer film (4) having an overall thickness of 50 μm was obtained. The interlayer adhesion strength between the surface resin layer (A) and the adhesive resin layer (B) of the obtained co-extruded multilayer film (4) is 20 N / 15 mm, and the adhesive resin layer (B)
Adhesive strength between resin and heat seal resin (C) is 15N / 1
5 mm.

Next, a paper substrate (basis weight 80 g / g) was placed on the surface resin layer (A) of the obtained co-extruded multilayer film (4).
cm ² ) with low density polyethylene (LDP) for lamination
E) Extrusion lamination by melt extrusion at 300 ° C. (MI = 20 g / min) was performed to obtain a laminated film (IV) that was laminated.

Test Examples 1-4 and Comparative Test Example 1 The co-extruded multilayer films (1), (2), (3), (4) and (3 ') obtained in Examples 1-4 and Comparative Example 3 were used. When slitting, a slitter speed for winding the film roll so as not to cause wrinkles was measured. Further, the workability was investigated by observing the degree of adhesion of the film to guide rolls and the like. The results are shown in Table 1.

[0057]

[Table 1]

Further, when the laminated films (I), (II), (III), and (IV) obtained in Examples 1 to 4 were slit, the degree of adhesion of the films to guide rolls and the like was observed, and the workability was improved. When the laminated films (I), (II), (III) and (IV) were examined, the heat-sealing resin layer (C) was laminated on the adhesive resin layer (B). There was no adhesion or stickiness between films, and no wrinkles were mixed during winding, and the workability was excellent.

Test Examples 5 to 8 and Comparative Test Examples 2 to 4 The laminated films (I), (II), (III), (IV) and (I ') obtained in Examples 1 to 4 and Comparative Examples 1 to 3 ), (I
A flange portion of a round cup container having a flange of 70 mm in outer diameter and a width of 5 mm made of the material shown in Table 3 using the lid materials of I ′) and (III ′) (the upper portion of polyethylene in a container made of paper polyethylene) ), After heat-sealing under the heat-sealing conditions shown in Table-3, opening feeling when opening,
After unsealing, the lid material and the container were pressed again with a finger, and then the opening strength (reseal strength) was checked again. Further, the state of the film remaining after the initial peeling was also examined. Table 2 shows the results.

In addition, the feeling of opening was evaluated as follows: when the lid was actually peeled off from the container and the required force was constant and smooth peeling was easy.
The case where the required force is not constant and the peeling lacks smoothness is set to ×, and the film remaining state is visually observed for the film remaining on the sealing surface of the flange portion and the lid material after peeling, the fluff standing state, the film remaining, A sample without fluff was evaluated as ○, a film remaining, and a sample with fluff was evaluated as ×.

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

The coextruded film of the present invention comprises a heat sealing resin layer (C) comprising a thermoplastic resin and a surface resin layer (A) comprising a pressure-sensitive adhesive resin layer (B) as a core layer and a thermoplastic resin. (A) / (B) / (C) are laminated in the order, so that there is no stickiness of the film and the workability is excellent. Further, the adhesive resin layer (B) and the heat seal resin layer (C) By controlling the interlayer adhesive strength and thickness of (3), it has an easy-opening function that can be opened by hand. Since the peeled surface after opening has an adhesive resin layer, it can be resealed (resealed) by the adhesive function. Becomes

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 53/00 B65D 53/00 A // B29L 7:00 B29L 7:00 (72) Inventor Takashi Sumiki Chiba (72) Nobuhiro Shiraiwa 5-20-13 Nakazuma, Ageo-shi, Saitama F-term (reference) 3E084 AB10 CC08 FA09 FD13 GB08 KA20 LA01 LB02 4F100 AK01A AK01B AK01C AK03A AK04B AK04J AK06C AK07A AK08B AK08J AK12B AK12J AK29B AK29J AK68B AK80B AL02B AL09B BA10A BA10C CA16B EH20A EH20B EH20C GB18 JB16A JB16B JB16C JL13 YY00A YY00B YY00C 4F207 AA03 A13 AAA AKA KBA

Claims (8)

[Claims] 1. A surface resin layer (A) containing a thermoplastic resin (a), and an adhesive resin layer (B) containing a rubbery thermoplastic resin (b1) and a tackifier (b2). ) And a heat-sealable resin layer (C) containing a thermoplastic resin (c) are laminated in the order of (A) / (B) / (C). The interlayer adhesive strength between the resin layer (B) and the heat seal resin layer (C) is 2 to 20 N
/ 15 mm, smaller than the interlayer adhesive strength between the surface resin layer (A) and the adhesive resin layer (B), and the thickness of the heat seal resin layer (C) is 0.5 to 10 μm. A co-extruded multilayer film. 2. A rubbery copolymer wherein the thermoplastic resin (a) is an olefin resin and the rubbery thermoplastic resin (b1) is a rubbery block copolymer containing a styrene block or ethylene as an essential component. The coalesced thermoplastic resin (c) is an olefin resin. A co-extruded multilayer film according to claim 1. 3. The rubbery thermoplastic resin (b1) is a styrene-butadiene-styrene block copolymer (SB)
S), a hydrogenated styrene-butadiene block copolymer rubber (HSBR), a styrene-isoprene-styrene block copolymer (SIS), and an ethylene-vinyl acetate copolymer (EVA). 1
The co-extruded multilayer film according to claim 2, which is at least one kind of rubbery copolymer. 4. The co-extruded multilayer film according to claim 2, wherein the thermoplastic resin (a) is a propylene-based resin, and the thermoplastic resin (c) is a low-density polyethylene. 5. The method according to claim 1, wherein the tackifier (b2) is a rosin-based resin,
A tackifier comprising at least one resin selected from the group consisting of terpene resins and petroleum resins.
5. The co-extruded multilayer film according to any one of 4. 6. The weight ratio (b1 / b) of the rubbery thermoplastic resin (b1) and the tackifier (b2) in the adhesive resin layer (B).
The coextruded multilayer film according to any one of claims 1 to 5, wherein 2) is 50/50 to 98/2. 7. The coextruded multilayer film according to claim 1, wherein the heat seal resin layer (C) is a resin layer containing a filler. 8. A lid material for a container, comprising the co-extruded multilayer film according to any one of claims 1 to 7.