JP5582669B2 - SEALANT RESIN COMPOSITION, SEALANT FILM AND USE THEREOF - Google Patents

Description

  The present invention relates to a sealant resin composition, a sealant film having both heat sealability and easy peel properties, and a laminate film and a container using the sealant film.

Technical background of the invention

  The sealant film having an easy peel property used for a container and packaging material is required to satisfy the conflicting performances of the sealing property and the easy peel property at the same time. Among them, regarding the sealing performance, it is required that the heat seal strength is always higher than the content that can protect the contents, and that the temperature dependency of the heat seal strength is small in order to cope with a wide variety of substrates. ing. On the other hand, with regard to easy peelability, it is heat-sealed to the extent that it can be easily peeled off by hand, and from the standpoint of good appearance and prevention of contamination of the contents, when the seal surface is peeled off (thread drawing) As a matter of course, there is a demand that the stringing phenomenon itself does not occur. In addition, in a sealant film for food packaging, it is desirable that the odor transfer from the film to the contents does not occur as much as possible.

  Many materials have been developed as resins for sealant films. For example, US Pat. No. 4,189,519 describes an easy peel sealand material composed of an ethylene-vinyl acetate copolymer (EVA) and poly 1-butene. U.S. Pat. No. 4,666,778 describes an easy peel sealant material made of ethylene resin, poly 1-butene, and polypropylene. However, according to studies by the present inventors, it has been found that in the former case, the acetic acid odor may be transferred to the contents, and in the latter case, it is difficult to adjust to an appropriate seal strength.

  JP-A-1-315,443 describes an easy peel sealant composition comprising poly 1-butene having an average molecular weight of 500,000 or more and low density polyethylene. However, since the molecular weight of poly 1-butene used is high and the melt flow rate is low, the molding method is limited and the control range of the seal strength is narrow. Also, RESEARCH DISCLOSURE (No. 38433) describes an easy peel laminate composed of poly 1-butene and polyethylene polymerized with a metallocene catalyst, but nothing is described regarding the stringing phenomenon itself. Absent. Furthermore, Japanese Patent Application Laid-Open No. 10-337829 also discloses that a composite film composed of a sealing layer made of low density polyethylene and poly 1-butene and a base material layer made of polyethylene resin has good sealing and unsealing properties. It is described that it is.

Problems to be solved by the invention

Therefore, the present invention has an appropriate balance between heat sealability and easy peel property, the temperature dependency of the heat seal strength during heat sealing is small, and the stringing phenomenon from the adhesive surface during peeling It aims at providing the sealant resin composition which is hard to generate | occur | produce.
Another object of the present invention is to provide a sealant film formed from the composition, and a laminate film and a container using the sealant film.

Means for solving the problem

  That is, the present invention is a resin composition containing a structural unit derived from ethylene and a structural unit derived from 1-butene, and the melt flow rate of the composition is 0.2 to 30 (g / 10 minutes). In addition, when the film formed from the composition is heat-sealed at 150 ° C., the sealing strength is 1 to 10 (N / 15 mm), and when the sealing surface is peeled off, the string-like resin residue is removed. The present invention relates to a sealant resin composition in which inspection does not substantially occur.

  The resin composition comprises an ethylene polymer having a melting point of 100 to 125 ° C. measured by a differential scanning calorimeter (DSC) and a 1-butene polymer having a melting point of 70 to 130 ° C. measured by the same method. A sealant resin composition is preferred. The resin composition preferably has two or more melting point peaks observed by DSC between 70 and 130 ° C., and the melting point peak having the maximum peak area is between 100 and 125 ° C. It is more desirable to be present. Such a resin composition desirably has a sea-island structure in its fine structure.

The present invention has an ethylene homopolymer having an melt flow rate of 2.0 to 30 (g / 10 min) and a density of 0.900 to 0.940 (g / cm ³ ) and an ethylene content of 85 to 99.99. 60 to 95% by weight of an ethylene polymer selected from an ethylene-α-olefin copolymer having an α-olefin content of 1.0 to 15 mol% at 9 mol%, and a melt flow rate of 0.1 to 25 (g / 10 minutes), a resin composition consisting of 5 to 40% by weight of a 1-butene polymer having a 1-butene unit content of 60 to 100 mol%, comprising an ethylene polymer melt flow rate (MFR _PE ) and 1-butene polymer Provided is a sealant resin composition in which the ratio of butene polymer to melt flow rate (MFR _PB ), MFR _PE / MFR _PB is 1.6-20. The 1-butene polymer desirably has a preferred density in the range of 0.880 to 0.925 (g / cm ³ ).

  The ethylene polymer may be an ethylene homopolymer or an ethylene / α-olefin copolymer, particularly a high-pressure low-density polyethylene, a linear ethylene / α-olefin copolymer, And their compositions are preferred. The 1-butene polymer may be a 1-butene homopolymer or a 1-butene / α-olefin copolymer. This resin composition is suitable for film forming, and can provide a film having both easy peel properties and heat seal properties.

  The present invention also relates to a sealant film having an easy peel property of 3 to 100 μm formed from the sealant resin composition, and can be produced by extrusion lamination molding, cast molding, or inflation molding. Even if this film is bonded to each other or bonded to another film and then the bonded surface is peeled off, there is a characteristic that the stringing phenomenon from the peeled surface is not substantially observed. .

  Further, the present invention is selected from the group consisting of the above-mentioned sealant film layer, a polyolefin film, a polystyrene film, a polyester film, a polyamide film, a laminated film of a polyolefin film and a gas barrier resin film, an aluminum foil, and a vapor deposition film. The laminate film comprising at least one film layer is suitable as a packaging material film having heat sealing properties and easy peel properties.

  One aspect thereof is selected from the group consisting of a sealant film layer, a polyolefin film layer, a polystyrene film, a polyester film, a polyamide film, a laminated film of a polyolefin film and a gas barrier resin film, an aluminum foil, and a vapor deposition film. A laminate film in which at least one film layer is laminated and integrated in this order can be exemplified.

  Furthermore, the present invention provides a method in which the laminate film is joined by heat sealing between the surfaces of the sealant film layers or by being joined to another resin molding by heat sealing. The present invention relates to a container that can be hermetically sealed. When the contents are food, there is almost no odor transfer from the container to the food.

Detailed Description of the Invention

  The present invention relates to a sealant resin composition containing an ethylene structural unit and a 1-butene structural unit, and a sealant film, a laminate film, and a container using the composition. To do.

Sealant resin composition (1)
The sealant resin composition (1) according to the present invention has a chemical structure containing at least a structural unit derived from ethylene and a structural unit derived from 1-butene, and is a so-called olefin resin. Since both structural units are present, this resin composition has heat sealing properties and easy peel properties.

Here, each structural unit can be detected by infrared absorption spectrum analysis. That is, when a press film of a resin composition is first prepared and the infrared absorption spectrum of the film is measured, the constitutional unit derived from ethylene has absorption in the region of 700 to 740 cm ⁻¹ and is derived from 1-butene. Since absorption exists in the area | region of 750-780 cm < ^-1 >, presence of both structural units can be confirmed.

  More specifically, this resin composition comprises an ethylene polymer having a melting point of 100 to 125 ° C. measured by a differential scanning calorimeter (DSC), and 1-butene having a melting point of 70 to 130 ° C. measured by the same method. It is desirable that the composition contains at least a polymer. Here, in the measurement by DSC, the composition sample is once heated from room temperature to 200 ° C. and melted, held at that temperature for 10 minutes, and then cooled to 0 ° C. at a rate of 10 (° C./min). The temperature rise is started again at a rate of 10 (° C./min), and an endothermic peak is observed in the process. The position of the endothermic peak is defined as the melting point of the polymer.

  In addition, it is desirable that the resin composition has two or more melting point peaks observed by DSC between 70 and 130 ° C., and a melting point peak having the maximum peak area exists between 100 and 125 ° C. It is more desirable to do. When the melting point peak having the maximum peak area is within the above range, the sealant film molded from this resin composition is excellent in low-temperature heat sealability, and the occurrence of the stringing phenomenon is substantially not caused when the adhesive surface is peeled off. Does not occur.

  Here, in the melting point measurement by DSC, when the endothermic peaks derived from the components contained in the resin composition are observed in a separated state, the peaks are compared and the larger one is the maximum peak area. A melting point peak having However, when the endothermic peaks are not separated and one peak is the shoulder of the other peak, the peak that is not the shoulder is the melting point peak having the maximum peak area. In addition, if the endothermic peaks are not completely separated and are observed in two peaks, calculate the product of the peak height and its half-width for each peak, and determine the larger peak value as the maximum peak area. Let it be the melting point peak it has.

  Such a resin composition preferably has a fine structure in which resins derived from at least two types of structural units form a sea-island structure. More preferably, it is desirable that the ethylene polymer and the 1-butene polymer have a sea-island structure. More preferably, it is a sea-island structure in which 1-butene polymer is dispersed like islands in an ethylene polymer sea. It is considered that the composition having such a sea-island structure expresses an appropriate balance between the heat sealability and the easy peel property.

  The fine structure of the resin composition should be observed with a transmission electron microscope (TEM) at a magnification of 10,000 times after making a thin section from a pellet-like or film-like composition sample using a microtome, etc., and staining with osmium. Can be confirmed.

  On the other hand, this resin composition has a melt flow rate value of 0.2 to 30 (g / 10 min), preferably 1 according to ASTM D-1238 and measured at 190 ° C. under a load of 2.16 kg. -25 (g / 10 minutes), more preferably 2-25 (g / 10 minutes), and even more preferably more than 2 and less than 25 (g / 10 minutes). When the melt flow rate value is within this range, the film formability from the resin composition is good and sufficient mechanical strength as a film layer is maintained.

  Moreover, when the film shape | molded from this resin composition is heat-sealed at 150 degreeC, the heat seal intensity | strength is 1-10 (N / 15mm), Preferably it is 1-8 (N / 15mm). When the heat seal strength is within this range, it has a practically sufficient adhesive strength and also has a good peel property, which is suitable as a packaging material.

  In the present invention, after heat-sealing the film to the adherend, it is important that the surface fluff of the sealant film layer called stringing does not substantially occur when the film is peeled off from the adhesive surface. In this way, the concern about contamination of the package contents can be eliminated. This stringing phenomenon can be confirmed by visual inspection.

  Such a sealant resin composition (1) of the present invention can be produced from, for example, an ethylene polymer and a 1-butene polymer, as described later.

Sealant resin composition (2)
The resin composition (2) according to the present invention is a composition containing at least an ethylene polymer and a 1-butene polymer described below. That is, the melt flow rate is 0.2 to 30 (g / 10 min), the density is 0.900 to 0.940 (g / cm ³ ) of ethylene polymer 60 to 95% by weight, and the melt flow rate is 0.00. 1 to 25 (g / 10 min), 1-butene unit content of 60 to 100 mol% 1-butene polymer 5 to 40% by weight, a resin composition comprising an ethylene polymer melt flow rate ( The ratio of MFR _PE ) to the melt flow rate (MFR _PB ) of the 1-butene polymer, that is, MFR _PE / MFR _PB is 1 or more.

<Ethylene polymer>
The ethylene polymer that can be used in the present invention may be an ethylene homopolymer or a copolymer of ethylene and an α-olefin, and the molecular structure thereof is linear. Alternatively, it may be branched having a long chain or a short side chain.

  In the case of a copolymer, the α-olefin as a comonomer is preferably an α-olefin having 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, and is randomly copolymerized with ethylene. Specific examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 3-methyl-1-butene and 3-methyl. -1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, and combinations thereof can be included, with small amounts of other comonomers as required. You may contain. The ethylene content in the copolymer is 85 to 99.9 (mol%), preferably 90 to 99.5 (mol%), and the α-olefin content is 0.1 to 15 (mol%), preferably Is preferably 0.5 to 10 (mol%).

The density of the ethylene polymer is 0.900 to 0.940 (g / cm ³ ), preferably 0.905 to 0.930 (g / cm ³ ), and is a category of so-called low density to medium density polyethylene. Belongs to. Within this density range, it has low-temperature heat-sealing properties, and when the container is finally manufactured from the film, the content of the inner layer film (sealant layer) surface is low, so the content can be filled at a high filling rate. Can be filled. The density is measured using a density gradient tube after the strand obtained at the time of measuring the melt flow rate described later is heat-treated at 120 ° C. for 1 hour and then gradually cooled to room temperature over 1 hour.

  The melt flow rate (MFR) is 0.2 to 30 (g / 10 min), preferably 1.0 to 190 ° C. under a load of 2.16 kg in accordance with ASTM D-1238. 25 (g / 10 minutes), more preferably in the range of 2.0 to 25 (g / 10 minutes). When it is within this range, the film can be formed at a high forming speed using an existing forming machine. The ethylene polymer preferably further has a melting point measured by DSC in the range of 100 to 125 ° C.

  An ethylene polymer having physical properties such as density, melt flow rate, and melting point within the above ranges is a homopolymerization of ethylene using a radical polymerization catalyst, a Philips type catalyst, a Ziegler-Natta catalyst, or a metallocene catalyst, or ethylene and α- It can be produced by copolymerizing with an olefin.

In particular, a so-called high-pressure low-density polyethylene produced using a radical polymerization catalyst in a tubular reactor or an autoclave reactor is preferred. Among them, a polymer satisfying the following formula is desirable for forming a film in the relationship between the melt flow rate (MFR) and the melt tension (measured value at 190 ° C .; unit mN; MT).
40 × (MFR) ^−0.67 ≦ MT ≦ 250 × (MFR) ^−0.67

  A linear ethylene / α-olefin copolymer produced using a Ziegler-Natta catalyst or a metallocene catalyst can also be preferably used. Long chain or short chain branching can be formed by adjusting the production conditions, and such ethylene / α-olefin copolymers can also be used.

  Furthermore, this ethylene polymer can also be used in the form of a composition produced by blending several types of ethylene polymers. For example, in the case of using a composition of a high-pressure method low-density polyethylene and a linear ethylene / α-olefin copolymer, a mixing ratio of the high-pressure method low-density polyethylene to the linear ethylene / α-olefin copolymer, that is, [ High-pressure low-density polyethylene] / [linear ethylene / α-olefin copolymer] is in the range of 0/100 to 75/25 (parts by weight), preferably 5/95 to 75/25 (parts by weight). When a certain composition is prepared, the balance between the seal strength and the peel strength can be easily adjusted.

  In other words, as the mixing ratio of high-pressure low-density polyethylene increases, the seal strength tends to decrease. Therefore, in applications that require easy peel properties, the mixing ratio of high-pressure low-density polyethylene is increased, and conversely high sealing strength is achieved. In a required field of application, if a prescription for increasing the mixing ratio of the linear ethylene / α-olefin copolymer is taken, it is possible to easily adjust the balance between the desired seal strength and peel strength.

<1-butene polymer>
The 1-butene polymer that can be used in the present invention is a homopolymer of 1-butene or a co-polymer of 1-butene and an α-olefin having 2 to 20 carbon atoms, preferably 2 to 10 excluding 1-butene. It is a polymer. Specific examples of α-olefins include the same α-olefins as described above, among which ethylene, propylene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferable. A small amount of other comonomer may be contained. The 1-butene content in the copolymer is 60 to 100 (mol%), preferably 70 to 100 (mol%), and the α-olefin content is 0 to 40 (mol%), preferably 0 to 30 (mol). %) Is desirable.

The density of the 1-butene polymer is preferably 0.880 to 0.925 (g / cm ³ ), more preferably 0.885 to 0.920 (g / cm ³ ), and is in this density range. And since the adhesiveness of the film surface formed from the resin composition is small, when a container is finally manufactured from a film, it is possible to fill the contents at a high filling rate.

  Further, the melt flow rate (MFR) is 0.1 to 25 (g / 10 min), preferably 1.0 to 1.0, measured under a load of 190 ° C. and 2.16 kg in accordance with ASTM D-1238. 25 (g / 10 minutes), more preferably 2 to 25 (g / 10 minutes), still more preferably more than 2 and 25 or less (g / 10 minutes), even more preferably 2.5 to 25 (g / 10) Min)).

  When the MFR of the 1-butene polymer is within this range, molding can be performed without applying an excessive load to the motor of the molding machine and at a low resin pressure. Therefore, even if the film forming speed is increased, the shear heat generation of the resin composition can be kept low, and the generation of odor and the deterioration of the blocking property of the film due to the oxidative deterioration of the resin composition can be suppressed. In addition, when the MFR value is lowered, surging during film forming (a phenomenon in which the amount of extrusion becomes nonuniform) tends to occur, and the film tends to cause unevenness in thickness and decrease in drawdown. If it is within the range, there is less concern. Furthermore, the heat seal strength can be easily adjusted, and the temperature dependency of the heat seal strength can be reduced.

  The 1-butene polymer preferably has a melting point measured by DSC in the range of 70 to 130 ° C.

  Such 1-butene polymers are disclosed in JP-B-64-7088, JP-A-59-206415, JP-A-59-206416, JP-A-4-218508, and JP-A-4-218507. It can be produced by a polymerization method using a stereoregular polymerization catalyst described in JP-A-8-225605. In the present invention, the aforementioned 1-butene polymer may be used singly or in combination of two or more.

<Resin composition>
The resin composition (2) of the present invention contains at least the above-described ethylene polymer and 1-butene polymer, and the mixing ratio of the ethylene polymer is 60 to 95% by weight, preferably 65 to 85%. The range of 1% by weight and 1-butene polymer is 5 to 40% by weight, preferably 15 to 35% by weight. Here, the total amount of both polymers is 100% by weight. When both polymers are within this mixing range, the film formed from the composition has an appropriate balance between its heat sealability and easy peel properties, i.e., required for packaging materials. A practical heat-sealing strength is ensured, and at the same time, an easy-opening property convenient for the user is obtained. Therefore, this resin composition can be suitably used for the production of an easy peel sealant film.

Further, the resin composition has a ratio of the melt flow rate (MFR _PE ) of the ethylene polymer to the melt flow rate (MFR _PB ) of the 1-butene polymer of 1 or more,
That is, 1 ≦ MFR _PE / MFR _PB ,
Preferably, 1 ≦ MFR _PE / MFR _PB ≦ 20,
More preferably, 1 ≦ MFR _PE / MFR _PB ≦ 10
It is desirable that When the relationship between the melt flow rate ratios of the two polymers satisfies the above range, the stringing phenomenon from the joint surface does not substantially occur when the heat-sealed joined body is peeled between the layers.

  That is, after forming a sealant film from this composition and heat-sealing the sealant films, or bonding the sealant film and a film such as polyethylene, ethylene / vinyl acetate copolymer or polypropylene by heat sealing. After that, even if a forced peeling operation from the adhesive surface is applied to the sealant film, the stringing phenomenon from the peeled portion hardly occurs.

  The resin composition preferably has a structure in which an ethylene polymer forms a matrix phase and a 1-butene polymer is microdispersed therein to form a dispersed phase, that is, the sea-island structure described above. In this case, the 1-butene polymer has a spherical shape and is dispersed by controlling the melt viscosity of the 1-butene polymer within the above-described range with respect to the melt viscosity of the ethylene polymer. Such a sea-island structure of the resin composition seems to be useful for preventing the occurrence of the stringing phenomenon at the time of peeling. The resin composition of the present invention more preferably has the physical properties of the resin composition (1) described above.

  If necessary, additives such as antioxidants, heat stabilizers, weathering stabilizers, slip agents, antiblocking agents and the like can be added to the resin composition within a range that does not deviate from the object of the present invention. Moreover, the crystal nucleating agent described in U.S. Pat. Nos. 4,320,209, 4,321,334, and 4,322,503 can be blended.

  In producing the composition, an ethylene polymer, a 1-butene polymer, and various additives as required are prepared, and they are mixed uniformly in a predetermined amount, and a kneading operation is added as necessary to obtain a resin composition. Product can be prepared. Mixing can be performed using a Henschel mixer, a Banbury mixer, a tumbler mixer, a single or twin screw extruder, and the like.

  Since the resin composition described so far has good moldability, it can be used for film molding as a resin for extrusion lamination molding, cast molding, or inflation molding, and is particularly suitable for extrusion lamination film molding. Yes.

Sealant Film By forming a film from the resin composition described above, a sealant film for a packaging material that requires easy peelability can be produced. The film may be formed by a cast molding method or an inflation molding method, and a film having a uniform film thickness and good appearance can be produced at high speed under the conditions of a resin temperature of 180 to 240 ° C. If the thickness of a film is 3-100 micrometers, it will be suitable as a sealant layer. Further, as will be described later, the sealant film layer can also be formed by a method of directly extruding and laminating onto the base film.

  This sealant film can be firmly bonded to each other by the adhesive strength of the sealant film when the heat seal operation is performed by overlapping the films, or when the heat seal operation is performed after stacking on another film. Since they can be separated from each other with a sufficient force, it can be used as a film having both heat-sealing properties and easy-peel properties. In addition, when the bonded film is forcibly peeled off, there is substantially no string-like resin residue on the peeled surface.

  Although heat sealing conditions are not particularly limited, bonding is performed with practically sufficient adhesive strength when performed under conditions of a normal sealing temperature of 120 to 180 ° C. and a sealing pressure of 0.1 to 0.5 (MPa). In addition, there is little variation in adhesive strength due to the sealing temperature. For example, when heat sealing is performed under the conditions of a sealing temperature of 150 ° C., a sealing pressure of 0.2 MPa, and a sealing time of 1 second, the adhesive strength at that time is in the range of 1 to 10 (N / 15 mm).

Laminate film This sealant film can of course be used alone, but it is generally used as a packaging film or packaging sheet in the construction of a laminate film laminated on a base film, and it is also used as a container material. Or it may be used as a container lid material.

  The base film is not particularly limited, but is a polyolefin film such as polyethylene or polypropylene, a styrene resin film, a polyester film such as polyethylene terephthalate or polybutylene terephthalate, nylon 6 or nylon 6,6. Polyamide film, laminated film of polyolefin film and gas barrier resin film such as polyamide resin and ethylene / vinyl alcohol copolymer resin, metal foil such as aluminum, aluminum, silica, etc. A vapor-deposited film or the like is appropriately selected and used depending on the intended use of the packaging material. This base film is not limited to one type, and two or more types can be used in combination.

  Since the sealant film layer is located in at least one of the outermost layers of the laminate film, the resin composition described above is directly or indirectly extruded onto the base film for lamination, or the base film and the sealant film are laminated. Can be dry-laminated, or a method of co-extrusion molding of resins constituting both layers can be employed.

  The structure of the laminate film is basically a combination of a sealant film and a base film, but when the adhesive force between the sealant film and the base film is not sufficient, a sealant film layer, It may be a laminate having at least a three-layer structure in which another film layer having adhesive properties and a base film layer are laminated in this order, and may be used in combination in any configuration depending on the intended packaging material. Can do.

  As one embodiment of the laminate film, a film having a constitution of sealant film layer / polyolefin film layer / other film layer can be mentioned. Examples of the other film layers include a layer selected from the group consisting of the above-mentioned polystyrene film, polyester film, polyamide film, laminated film of polyolefin film and gas barrier resin film, aluminum foil, and deposited film. Can do.

  When the polyolefin film layer and the other film layer cannot be bonded with sufficient adhesive strength, a structure of sealant film layer / polyolefin film layer / adhesive layer / other film layer can be employed. When an anchor coating agent such as a urethane or isocyanate adhesive is used as the adhesive layer, or a modified polyolefin such as an unsaturated carboxylic acid grafted polyolefin is used as the adhesive resin, the adjacent layers can be firmly bonded.

Container Prepare two laminated films as described above and face each other with the sealant film layers facing each other, bend the laminated film so that the sealant film layer faces each other, or the sealant film layer of the laminated film and another film Then, the surroundings are heat-sealed so that a desired container shape is formed from either one of the outer front west sides, for example, a bag-like container can be manufactured. When this bag-shaped container molding process is combined with the contents filling process, that is, the bottom and sides of the bag-shaped container are heat-sealed, then the contents are filled, and then the top is heat-sealed. Can be completed. Therefore, the laminate film can be used by supplying it to an automatic packaging device for solids such as snacks, powders, or liquid materials.

  In addition, a laminated film or sheet, or another film or sheet is previously formed into a cup-shaped container shape by means such as vacuum forming or deep drawing, or a normal injection molded container is prepared, Then, a laminate or other film is coated as a lid, and heat sealed from the upper part of the container or along the periphery of the side part to obtain a package containing the contents. In this case, the sealant film according to the present invention can be used for either the sealant layer of the lid member, the sealant layer of the container body, or both. This container can be suitably used for packaging cup ramen, miso, ham, bacon, jelly, pudding, snacks and the like.

  The structure and manufacturing method of the container are not limited to the above description, and can be arbitrarily changed. In addition, other films or containers that can be used in combination with the sealant film or laminate film according to the present invention are packaging materials molded from resins such as polyethylene, ethylene / vinyl acetate copolymer, and polypropylene that have been used conventionally. Can be used as is. For example, a container-like molded body having a ridge at the opening is formed from such a material, laminated so that the sealant film layer surface is superimposed on the ridge of the opening, and both surfaces are joined by heat sealing. A container package can be formed. The sealant film or sealant film layer and the packaging material described above can be heat-sealed with sufficient adhesive strength and can be easily opened because they have easy peel properties. Therefore, this container can be suitably used particularly in the field of food packaging as a packaging container having a sealing property and an easy peel property.

EXAMPLES Next, the present invention will be described through examples, but the present invention is not limited to the examples.
First, Table 1 shows the types and physical properties of the resins used.

（註）コモノマーの種類：ＭＰ；４−メチル−１−ペンテン、Ｈ；１−ヘキセン
Ｂ；１−ブテン、 Ｅ；エチレン
樹脂製造時の重合触媒：Ｔ；チタン系触媒、 Ｍ；メタロセン系触媒
Ｒ；ラジカル触媒

(Ii) Type of comonomer: MP; 4-methyl-1-pentene, H; 1-hexene
B: 1-butene, E: Polymerization catalyst for production of ethylene resin: T; Titanium catalyst, M: Metallocene catalyst
R: radical catalyst

(Examples 1-9) (Comparative Examples 1-3)
A resin composition for a sealant layer was produced by using the resins listed in Table 1 and mixing at the blending ratios listed in Table 2. Next, using a linear low density polyethylene (density 0.920 g / cm ³ , melt flow rate 2.0 g / 10 min) as a resin for the base film layer, a two-layer film having the following constitution was formed.
Composition of film: base material layer (50 μm) / sealant layer (20 μm)

  In forming a two-layer film, an extruder having a screw diameter of 40 mm is used for forming a base material layer, an extruder having a screw diameter of 30 mm is used for forming a sealant layer, and a multilayer cast molding machine having a die width of 30 cm. It was used. The molding temperature was 220 ° C. for each layer, the temperature of the chill roll was 30 ° C., and the film take-up speed was 10 (m / min).

  Table 2 shows the results of the melting point peak of the resin composition of the sealant layer measured with a differential scanning calorimeter (DSC) and the presence or absence of phase separation (sea-island structure) measured with a transmission electron microscope (TEM). .

  In addition, in order to evaluate the physical properties of the obtained two-layer film, the optical properties, heat seal strength, and presence / absence of stringing from the peeled surface were measured by the following methods, and the results are shown in Table 2.

(1) Optical properties: HAZE was measured according to the method of ASTM D1003-61 and displayed in unit%.

(2) Heat seal strength: Two strip-shaped test pieces having a width of 15 mm were prepared and arranged so that the sealant layers face each other, and then at a predetermined temperature from the base film side, pressure 0.2 MPa, seal Heat sealing was performed under the condition of time 1 second. Thereafter, the layers were peeled in the 180 ° direction at a speed of 300 (mm / min), the peel strength at that time was measured, and the value was expressed as heat seal strength (N / 15 mm width).

(3) Threading phenomenon: The peeled state of the seal surface after the heat seal strength measurement was visually observed and evaluated according to the following criteria.
○: A state in which the thread drawing phenomenon does not occur and the sealing surface shows a good appearance.
X: A state in which the thread drawing resin is left as a residue on the seal surface and the appearance is not good.

As is apparent from the results shown in Table 2, the heat seal strength necessary for practical use can be obtained by forming a sealant layer from the composition of the ethylene polymer and 1-butene polymer used in each example. The heat seal strength is in a range that can be peeled by hand, and a laminate film balanced between the two is obtained. Moreover, the phenomenon of stringing is not seen at the time of peeling, and it turns out that it is suitable as a packaging material. Further, when considered together with the comparative example, it can be seen that the value of MFR _PE / MFR _PB is closely related to the occurrence of the yarn drawing phenomenon.

(Examples 10 to 12) (Comparative Example 4)
A composition containing 75% by weight of PE2 described in Table 1 and 25% by weight of PB2 as a sealant layer was used, and a linear low density polyethylene (density 0.920 g / cm ³ , Using a melt flow rate of 2.0 g / 10 min, a two-layer film having the following constitution was formed.
Composition of film: base material layer (50 μm) / sealant layer (20 μm)

  An extruder with a screw diameter of 40 mm was used for forming the base material layer, an extruder with a screw diameter of 30 mm was used for forming the sealant layer, and a multilayer cast molding machine with a die width of 30 cm was used. The molding temperature was 220 ° C. for each layer, the temperature of the chill roll was 30 ° C., and the film take-up speed was 10 (m / min).

  Various adherend films (thickness: 200 μm) described in Table 3 are superimposed on the sealant layer side of the obtained two-layer film, and heat sealing is performed under the same conditions as those used in the above-described method for measuring heat seal strength. Thereafter, the heat seal strength was measured. The presence or absence of the occurrence of stringing phenomenon on the peeled surface was also observed at the same time, and the results are also shown in Table 3.

＊ ＬＤＰＥ：低密度ポリエチレン ＨＤＰＥ：高密度ポリエチレン
ＰＰ：プロピレンホモポリマー ＰＳ：ポリスチレン

* LDPE: Low density polyethylene HDPE: High density polyethylene PP: Propylene homopolymer PS: Polystyrene

Examples 13 to 15 (Comparative Example 5)
In Example 10, except that the resin composition used for forming the silant layer was changed to a composition produced from 60% by weight of PE1, 15% by weight of PE4 and 25% by weight of PB1 listed in Table 1. As in Example 10, a bilayer film was formed.

  Various adherend films (thickness: 200 μm) described in Table 4 are superimposed on the sealant layer side of the obtained two-layer film, and heat sealing is performed under the same conditions as those used in the above-described method for measuring heat seal strength. Thereafter, the heat seal strength was measured. The situation of the presence or absence of the stringing phenomenon on the peeled surface was also observed at the same time. The results are also shown in Table 4.

  As is apparent from the results shown in Table 3 and Table 4, when the adherend is a polyethylene film or a polypropylene film, it adheres well to the sealant film layer, and its heat seal strength is also evaluated as an easy peel property. It is in the range that can be done. Moreover, the stringing phenomenon is not seen at the time of peeling, and it turns out that it is suitable as a packaging material. However, it did not adhere to the polystyrene film.

(Example 16)
A two-layer film in which a polyester (PET) film having a thickness of 12 μm and a low-density polyethylene film having a thickness of 25 μm are bonded using an anchor coating agent is prepared, and a sealant film layer having a thickness of 20 μm is formed on the surface of the low-density polyethylene film. Were laminated by extrusion lamination method to obtain a three-layer film.
As a resin for forming the sealant film layer, a resin composition produced from 80% by weight of PE5 and 20% by weight of PB3 described in Table 1 was used.

For extrusion lamination, an extrusion lamination molding machine having a screw diameter of 65 mmφ and a die width of 500 mm was used, and the set temperatures of the extruder were as follows.
C1 / C2 / C3 / C4 / D = 200/270/305/305/305 (° C.) The processing speed was 80 (m / min).

  The molding conditions during extrusion lamination molding and the properties of the resulting three-layer film were examined, and the results are shown in Table 5. In Table 5, neck-in, draw-down property, and heat seal strength were measured by the following methods.

(1) Neck-in: Neck-in of both ears was measured when the sealant film was molded under conditions of a thickness of 20 μm and a take-off speed of 80 (m / min).

(2) Drawdown property: The take-up speed of the sealant film was increased from the conditions at the time of neck-in measurement, and indicated by the take-up speed when the film was cut.

(3) Heat seal strength: The same conditions as in the above-described method for measuring heat seal strength, with a high-pressure method low-density polyethylene film having a thickness of 200 μm superimposed as an adherend on the sealant layer side of the obtained three-layer film Then, heat sealing was performed, and then the heat sealing strength was measured. At the same time, the presence or absence of the stringing phenomenon on the peeling surface was also observed.

(Comparative Example 6)
In Example 16, a three-layer film was obtained in the same manner as in Example 16 except that a resin composition produced from 80% by weight of PE5 and 20% by weight of PB4 was used as the resin for forming the sealant film layer. It was. The molding situation during extrusion lamination molding and the properties of the obtained three-layer film were examined, and the results are also shown in Table 5.

  As is apparent from the molding situation of Example 16 shown in Table 5, the resin composition used in Example 16 has a small neck-in and excellent draw-down property, and is caused by deterioration of the resin during molding. No fumes were seen. Here, increasing the neck-in value indicates that the difference in thickness between the center and both ends of the film increases, and the cross-sectional area at both ends of the film must be increased during film production, which is preferable in practice. Absent. The drawdown property is an index of productivity. If the drawdown property is small, high speed molding becomes difficult.

Effect of the invention

  The sealant resin composition according to the present invention has good film moldability, the film molded therefrom has a practically sufficient heat seal strength, and there is a proper balance between the heat seal property and the peel property. It is kept. Moreover, since the temperature dependency of the heat seal strength at the time of heat sealing is small, the film has excellent suitability for automatic packaging machines. Furthermore, when the sealing surface when heat-sealed is forcibly peeled, the resin residue is hardly left in the threaded state on the sealing surface, and the film is suitable for food packaging. In addition, the film is less likely to cause blocking, and odor is hardly transferred to the package.

  Accordingly, a sealant film formed from the resin composition, a laminate film using the sealant film, and a container are suitable as an easy-peeling sealed packaging material, and particularly suitable for food packaging.

Claims (18)

An ethylene homopolymer having a melt flow rate of 2.0 to 30 (g / 10 min), a density of 0.900 to 0.940 (g / cm ³ ), and an ethylene content of 85 to 99.9 mol% 60 to 95% by weight of an ethylene polymer selected from ethylene-α-olefin copolymers having an α-olefin content of 0.1 to 15 mol%, and a melt flow rate of 1.0 to 25 (g / 10 min), A resin composition comprising 1-butene unit content of 5 to 40% by weight of 1-butene unit content of 60 to 100 mol%, comprising an ethylene polymer melt flow rate (MFR _PE ) and 1-butene polymer The ratio of the melt flow rate (MFR _PB ), MFR _PE / MFR _PB is 1.6 to 20, and the sealant resin composition.
2. The sealant resin composition according to claim 1, wherein the 1-butene polymer has a density of 0.880 to 0.925 (g / cm ³ ).
The sealant resin composition according to claim 1 or 2, wherein the 1-butene polymer has a melt flow rate of 2 to 25 (g / 10 min).
The sealant resin composition according to claim 1 or 2, wherein the 1-butene polymer has a melt flow rate of 2.5 to 25 (g / 10 min).
The sealant resin composition according to any one of claims 1 to 4, wherein the 1-butene polymer is a 1-butene homopolymer.
The sealant resin according to any one of claims 1 to 4, wherein the 1-butene polymer is a copolymer of 1-butene and an α-olefin having 2 to 20 carbon atoms excluding the 1-butene. Composition.
The sealant resin composition according to claim 1, wherein the ethylene polymer is a high-pressure low-density polyethylene.
The ethylene polymer is a linear ethylene / α-olefin copolymer composed of ethylene and an α-olefin having 3 to 20 carbon atoms, according to any one of claims 1 to 6. Sealant resin composition.
The sealant resin composition according to any one of claims 1 to 6, wherein the ethylene polymer is a composition comprising a high-pressure low-density polyethylene and a linear ethylene / α-olefin copolymer. object.
The ethylene polymer has a mixing ratio of 0/100 to 75/25 (parts by weight) with respect to the linear ethylene / α-olefin copolymer of high-pressure low-density polyethylene. The sealant resin composition described in 1.
The sealant resin composition according to any one of claims 1 to 10, wherein the resin composition is a resin for extrusion lamination molding, cast molding, or inflation molding.
It is a film which consists of a sealant resin composition in any one of Claims 1-11, Comprising: The thickness is 3-100 micrometers, The sealant film characterized by the above-mentioned.
The sealant film according to claim 12, wherein the film is manufactured by extrusion lamination molding, cast molding, or inflation molding.
Laminate film comprising a layer of sealant film of claim 12 or 13, that consists of a layer of laminate fill beam of polyolefin films or polyolefin films and polyester films.
The sealant film layer according to claim 12, a polyolefin film layer, a polystyrene film, a polyester film, a polyamide film, a laminated film of a polyolefin film and a gas barrier resin film, an aluminum foil, and a vapor deposition film. At least one other film layer selected from the group is in this order , or an adhesive layer made of an adhesive resin which is a urethane adhesive, an isocyanate adhesive or a modified polyolefin between the polyolefin film layer and the other film layer. And a laminated film characterized by being laminated in this order .
A container, wherein the laminate film according to claim 14 or 15 is sealed by heat sealing between the surfaces of the sealant film layers.
Sealing is performed by heat-sealing the sealant film layer surface of the laminate film according to claim 14 or 15 and a molded product of a resin selected from the group consisting of polyethylene, ethylene / vinyl acetate copolymer, and polypropylene. A container characterized by being made.
  The container according to claim 17, wherein the molded body is a container-shaped molded body having a ridge at an opening, and the sealant film layer surface is overlapped and joined to the ridge of the opening. .