KR20160147721A - Multilayer sealant film - Google Patents

Abstract

The present invention provides a sealant film which has a high heat seal strength and which can be easily opened without depending on heat seal conditions. A multilayer sealant film comprising a laminate layer as an outermost layer, an intermediate layer of at least one layer, and a heat seal layer as an outermost layer on the other side, wherein the laminate layer is attached to a base film with the laminate layer side as an attachment surface, 30 to 70 parts by weight of a polybutene resin, 20 to 60 parts by weight of a linear low-density polyethylene resin and 10 to 50 parts by weight of a low-density polyethylene resin having a density of 0.930 g / cm3 or more, wherein the intermediate layer is a long- And a resin containing 50 to 100 parts by weight of low-density polyethylene, and the heat-seal layer comprises a resin containing a propylene-based random copolymer.

Description

Multilayer sealant film {MULTILAYER SEALANT FILM}

The present invention relates to a multilayer sealant film. More particularly, the present invention relates to a multilayer sealant film which is provided with a sealed package which can be easily opened with a light force without generation of a piece of yarn or a peel on the film when the heat seal portion is opened.

BACKGROUND ART [0002] Packaging bags that can be sealed by heat sealing are widely used for packaging various products such as foods, medical care (apparel), and industrial parts.

Such a packaging bag includes a packaging material formed by laminating a base film and a sealant film having an outermost layer of a heat seal layer for enabling heat sealing. The packaging material is used as a sealed package by molding the packaging material into a bag shape so that the heat-sealing layer is inward, and then storing the contents therein, followed by thermocompression bonding the heat-sealing layer of the opening.

When the sealed package is opened, the vicinity of the heat seal portion of each of the front and back films constituting the package is held by the fingertips of the left and right hands, and the two sealed films are pulled in the direction of separating to break the heat seal portion to regenerate the opening The method is common.

The heat seal of the sealed package requires a sufficient strength so as not to be opened at the time of transportation, storage, sale, etc., but it is necessary that the end consumer is weak enough to be easily opened by the above-described opening method. In general, it is considered that the heat seal strength and the ease of opening are difficult to be compatible with each other.

The sealant film may be a multilayer film including a heat-seal layer which is melted or softened by heat to enable heat sealing of the packaging material. As the sealant film, heat seal strength, ease of opening, and other considerations have been studied, and various layer structures have been proposed. Japanese Patent No. 4040738 discloses a laminate comprising a layer containing a mixture of linear low density polyethylene (LLDPE) and polyethylene, a sealant film comprising a laminate of a layer containing a polypropylene resin,

Japanese Patent No. 4300648 discloses an easy-to-open polyolefin laminate comprising a laminate layer containing LLDPE, an intermediate layer comprising a mixture of polypropylene (PP) and LLDPE, and a heat-seal layer containing PP . In the case of opening the package produced by using these sealant films, interlayer delamination between the base film and the sealant film or between the layers constituting the sealant film is taken. In addition to these patent documents, there are many proposals for a sealant film for performing the opening by delamination.

Summary of the Invention

As described above, the heat seal strength and ease of opening are generally incompatible with each other.

It is an accident that the contents should not be contaminated at the time of transportation, storage, and sale of the product, for example, for food businesses, etc., in which the product is stored in a sealed package. Therefore, in order to complete the heat seal of the package, the heat seal may be carried out under conditions more severe than the conditions specified by the packaging material maker.

If the sheet is sealed under high temperature, high pressure and long time conditions, the heat seal strength is improved. However, for example, excessive interlayer adhesion causes deterioration of delamination between layers at the time of opening. As a result, So that it becomes difficult to be damaged.

The present invention has been made to overcome the above-mentioned phenomenon.

An object of the present invention is to provide a sealant film which has a high heat seal strength and which can be easily opened without depending on the heat seal condition.

The inventors of the present invention have conducted diligent studies to achieve the above object, and as a result, it has been found that not only by interlayer delamination but also by cohesive failure in which one layer of the multilayer constituting the sealant film is broken and interlayer delamination are combined to realize opening The present inventors have found that a multilayered film can be provided which is provided with a sealed package which can be easily opened and opened easily regardless of heat sealing conditions.

That is, according to the present invention, the objects and advantages of the present invention are, firstly,

A laminate layer (A) as an outermost layer,

At least one intermediate layer (B)

And the heat seal layer (C), which is the outermost layer,

(A) side as an attachment surface to be adhered to a substrate film, wherein the multilayer sealant film is a multilayer sealant film,

Wherein the laminate layer (A)

30 to 70 parts by weight of a polybutene resin (A1)

20 to 60 parts by weight of a linear low-density polyethylene resin (A2)

(A1), a linear low density polyethylene resin (A2) and a low density polyethylene resin (A3), and a low density polyethylene resin (A3) having a density of 0.930 g / cm3 or more. Is 100 parts by weight,

Wherein at least one layer of the intermediate layer (B) of the at least one layer comprises a long-chain branched low density polyethylene (B1) having the following characteristics (1) to (3), the total amount of the resins constituting the intermediate layer By weight and 50 to 100 parts by weight,

Wherein the heat seal layer (C) is obtained by the multilayer sealant film comprising a resin containing a propylene-based random copolymer;

(1) the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography is 7.5 to 15.0,

(2) the amorphous component amount measured by the temperature rising fractionation method is 1 to 4% by weight, and

(3) the number of branches having 8 or more carbon atoms measured by ¹³ C-NMR is 1.5 to 5.0 per 1,000 carbon atoms.

The above objects and advantages of the present invention are achieved by a packaging material obtained by attaching the multilayer sealant film on a base film with the laminate layer (A) as an attachment surface.

The above objects and advantages of the present invention are achieved by a pillow packaging bag made of the packaging material and a sealed package obtained by heat-sealing the opening of the packaging bag after the contents are stored in the pillow packaging bag.

Other objects and advantages of the present invention will become apparent from the following description.

1 is a schematic cross-sectional view of a packaging material 2 of the present invention.
2 is a schematic explanatory view of the sealed package 5 of the present invention.
3 is a schematic explanatory diagram for explaining a mechanism at the time of opening the heat-sealed portion of the sealed package of the present invention.

Hereinafter, the present invention will be described in detail.

In the present specification, the term "packaging material" refers to a material for producing a packaging bag obtained by attaching the multilayered sealant film of the present invention to a base film.

&Quot; Packing bag " means a bag-shaped material having an opening portion obtained by processing a packaging material.

The term " sealed package " refers to a sealed bag obtained by storing contents in a packaging bag and heat sealing the opening portion.

As described above, in the multilayered sealant film of the present invention,

A laminate layer (A) as an outermost layer,

At least one intermediate layer (B)

And the heat seal layer (C), which is the outermost layer,

.

Hereinafter, each layer constituting the multilayered sealant film of the present invention will be described in detail.

In the present specification, the density of the resin is a value measured in accordance with ASTM D1505;

The melting point of the resin is the peak top temperature of the peak showing the maximum endothermic curve in the endothermic curve at the time of heating using the differential scanning calorimeter,

The melt flow rate (MFR) is a value measured under a load of 2.16 kg at a temperature specified below for each resin in accordance with JIS K 6758.

≪ Laminate layer (A) >

When the multilayered sealant film of the present invention is laminated with a base film to form a packaging material, the laminate layer (A) is located on the base film side and is used for adhesion to the base film. When the release layer is peeled off from the middle layer Lt; / RTI >

This laminate layer (A)

Polybutene resins (A1),

The linear low density polyethylene (A2) and

And a low-density polyethylene (A3) having a density of 0.930 g / cm3 or more.

The compatibility of the polybutene resin (A1) with other resins is lowered because the laminate layer (A) contains the low density polyethylene (A3) together with the polybutene resin (A1) and the straight chain low density polyethylene (A2) The cohesive failure of the laminate layer (A) improves at the time of opening of the package, contributing to the openability. Since the cohesive failure property depends on the commercial state of the resin constituting the laminate layer, the cohesive failure property can obtain the desired unsealing property regardless of the heat sealing condition at the time of forming the package. Since the polybutene resin (A1) and other resins are originally used for emergency, the laminate layer (A) containing the polybutene resin (A1) has irregularities on the surface thereof, .

Further, by adjusting the ratio of the polybutene resin (A1), the linear low density polyethylene (A2) and the low density polyethylene (A3) within the following range, a high level of transparency and image clarity can be obtained.

[Polybutene resin (A1)]

The polybutene resin (A1) is selected from a homopolymer of 1-butene and a copolymer of 1-butene and another? -Olefin. The? -Olefin is preferably an? -Olefin having 2, 3 or 5 to 10 carbon atoms, and specific examples thereof include ethylene, propylene, 1-pentene, 1-hexene, . As the copolymer of 1-butene and another? -Olefin, for example, a copolymer of 1-butene and at least one? -Olefin selected from the group consisting of ethylene and propylene is preferable.

Specific examples of the polybutene resin (A1) include homopolymers of 1-butene, ethylene / 1-butene copolymers, propylene / 1-butene copolymers or ethylene / propylene / 1-butene copolymers. As the above-mentioned copolymer, a random copolymer is preferable.

The content of the 1-butene unit in the polybutene resin (A1) is preferably 50 parts by weight or more, more preferably 70 parts by weight or more, when the total amount of the copolymer is 100 parts by weight. The most preferred polybutene resin (A1) is a homopolymer of 1-butene.

The density of the polybutene resin (A1) is preferably 0.900 to 0.930 g / cm3, more preferably 0.910 to 0.920 g / cm3. When the density of the polybutene resin is too low, blocking of the multilayer sealant film tends to occur.

When the density is too high, the multilayered sealant film is curled and the handling property is deteriorated.

The polybutene resin (A1) preferably has a melting point of 50 to 135 占 폚, more preferably 70 to 125 占 폚. When the melting point is lower than 50 占 폚, the appearance of the release surface at the time of opening becomes poor. When the melting point exceeds 135 占 폚, the opening strength may become excessively high. When the melting point of the polybutene resin (A1) is too low, blocking of the multilayered sealant film is likely to occur. On the other hand, when the melting point of the polybutene resin is excessively high, the heat seal starting temperature becomes high. In particular, when biaxially oriented polypropylene is employed as the base film, heat shrinkage tends to occur at a high temperature, and such a packaging material is not preferable because the allowable range of the heat seal temperature is narrowed.

The MFR (190 DEG C) of the polybutene resin (A1) is preferably 0.1 to 50.0 g / 10 min, more preferably 1.0 to 20.0 g / 10 min, in consideration of film forming property. When the MFR is less than 0.1 g / 10 min, the opening strength of the package becomes excessively high. On the other hand, when the MFR exceeds 50.0 g / 10 min, the appearance of the release surface at the time of opening becomes poor. When the MFR of the polybutene resin is too low, the viscosity at the time of melting is high. Therefore, in the production of the multilayer sealant film, the resin pressure in the extruder rises and the productivity is markedly deteriorated. On the other hand, When the MFR is too high, blocking of the multilayer sealant film tends to occur.

The content of the polybutene resin (A1) in the laminate layer (A) is such that the total amount of the polybutene resin (A1), the linear low density polyethylene (A2) and the low density polyethylene (A3) in the laminate layer (A) Is 30 to 70 parts by weight, preferably 35 to 60 parts by weight, based on the weight of the composition. When the content of the polybutene resin (A1) is less than 30 parts by weight, cohesive failure of the laminate layer (A) is difficult to occur at the time of opening, and the opening strength becomes excessively high, so that film tear easily occurs at the time of opening . On the other hand, when the content of the polybutene resin (A1) exceeds 70 parts by weight, the appearance of the release surface at the time of opening becomes poor.

[Linear low density polyethylene (A2)]

The linear low-density polyethylene (A2) is a thermoplastic resin obtained by copolymerization of ethylene and other? -Olefins in small amounts. Examples of the? -Olefin include 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene. The content of the -olefin unit in the linear low-density polyethylene (A2) is preferably 30 mol% or less, and more preferably 2 to 20 mol%.

The density of the linear low density polyethylene (A2) is preferably 0.900 to 0.945 g / cm3, more preferably 0.910 to 0.940 g / cm3. When the density of the linear low density polyethylene (A2) is too low, the transparency and image clarity of the packaging material may be insufficient, and blocking of the multilayered sealant film tends to occur. On the other hand, when the density of the linear low-density polyethylene (A2) is too high, the multilayered sealant film may curl and the handling property may be deteriorated.

The melting point of the linear low-density polyethylene (A2) is preferably 130 占 폚 or lower, and more preferably 100 to 130 占 폚. When the melting point of the linear low-density polyethylene (A2) is too low, blocking of the multilayered sealant film tends to occur easily. On the other hand, when the melting point of the linear low-density polyethylene (A2) is too high, the multilayered sealant film may curl and the handling property may be deteriorated.

The MFR (190 DEG C) of the linear low-density polyethylene (A2) is preferably 0.1 to 50.0 g / 10 min, and more preferably 2.0 to 20.0 g / 10 min. When the MFR of the linear low-density polyethylene (A2) is too low, the viscosity at the time of melting becomes excessively high, so that the resin pressure in the extruder rises at the time of producing the multilayer sealant film, and the productivity is remarkably deteriorated. On the other hand, when the MFR of the linear low-density polyethylene (A2) is too high, blocking of the multilayer sealant film tends to occur.

The content of the linear low density polyethylene (A2) in the laminate layer (A) is preferably 100 parts by weight of the total of the polybutene resin (A1), the linear low density polyethylene (A2) and the low density polyethylene (A3) in the laminate layer (A) Is 20 to 60 parts by weight, preferably 25 to 50 parts by weight, based on the weight of the composition. When the content of the linear low-density polyethylene (A2) is less than 20 parts by weight or exceeds 60 parts by weight, the tearing strength becomes excessively high in any case, so that film tear easily occurs at the time of opening.

[Low density polyethylene (A3)]

The density of the low density polyethylene (A3) is preferably 0.930 g / cm3 or more, and more preferably 0.930 to 0.950 g / cm3. When the density of the low-density polyethylene (A3) is too low, the influence on the transparency is small, but the image clarity is greatly deteriorated. Further, blocking of the multilayer sealant film tends to occur. On the other hand, when the density of the low-density polyethylene (A3) is excessively high, the multilayered sealant film is curled and the handling property is deteriorated.

The melting point of the low-density polyethylene (A3) is preferably 120 占 폚 or lower, and more preferably 100 to 120 占 폚. When the melting point of the low-density polyethylene (A3) is too low, blocking of the multilayered sealant film tends to occur. On the other hand, when the melting point of the low-density polyethylene (A3) is excessively high, the multilayered sealant film is curled and the handling property is deteriorated.

The MFR (190 DEG C) of the low-density polyethylene (A3) is preferably in the range of 0.1 to 50.0 g / 10 min, and more preferably in the range of 2.0 to 20.0 g / 10 min. When the MFR of the low-density polyethylene (A3) is too low, the viscosity at the time of melting is high, so the resin pressure in the extruder increases in the production of the multilayer sealant film and the productivity is markedly deteriorated. On the other hand, When the MFR is too high, blocking of the multilayer sealant film tends to occur.

As such low-density polyethylene (A3), high-pressure processed low-density polyethylene (HPLD), which is generally produced by a high-pressure method, can be preferably used.

The content of the low density polyethylene (A3) in the laminate layer (A) is 100 parts by weight in total of the polybutene resin (A1), the linear low density polyethylene (A2) and the low density polyethylene (A3) in the laminate layer (A) 10 to 50 parts by weight, and preferably 20 to 40 parts by weight. When the content is less than 10 parts by weight, the opening strength becomes excessively high, and film tearing at the time of opening tends to occur. When the amount is more than 50 parts by weight, image clarity is deteriorated.

[Parameter Control of Resin Contained in Laminate Layer (A)] [

The density, melting point, MFR, etc. of the polybutene resin (A1), the linear low density polyethylene (A2) and the low density polyethylene (A3) can all be controlled by known means. For example, the kind and copolymerization amount of the comonomer, the molecular weight of the resin, and the like. In addition, among various commercially available products, materials having desired properties can be selected and used.

[Other components]

The laminate layer (A) contains, in addition to the respective components (A1) to (A3), other components such as a binder resin, a binder resin, May be contained. Examples of the other components include petroleum resins, terpene resins, rosins, antiblocking agents, antioxidants, light stabilizers, lubricants, antistatic agents, antifogging agents, coloring agents, nucleating agents and antibacterial agents.

[Method of producing laminate layer (A)

The laminate layer (A) can be obtained by melt-mixing the components (A1) to (A3) and other components to be used as required, and film-forming the film. For example, an extruder or the like may be used for the melt mixing, and a T-die or the like may be used for the film formation.

The thickness of the laminate layer (A) is preferably 1.5 mu m or more, more preferably 2 mu m or more, in order to effectively cause cohesive failure. On the other hand, if the laminate layer is too thick, not only a large amount of energy is required to break but also the economical efficiency is low and the weight of the package increases, so that the thickness of the laminate layer A is not more than 50 탆, 50 mu m, and more preferably 30 mu m or less.

≪ Intermediate layer (B) >

The intermediate layer B is formed between the laminate layer A and the heat-seal layer C to firmly adhere the laminate layer A and the heat-seal layer C to each other.

The intermediate layer (B) includes a resin containing 50 to 100 parts by weight of long chain branched low density polyethylene (B1) in the case where the total amount of the resins constituting the intermediate layer (B) is 100 parts by weight. The thickness of the intermediate layer (B) is preferably 5 to 100 mu m.

[Long-chain branched linear low-density polyethylene (B1)]

Chain branched low density polyethylene (B1) in the intermediate layer (B) constituting the multilayered sealant film of the present invention is a low density polyethylene having a branched structure, the LLDPE (linear low density polyethylene, described later) and LDPE (low density polyethylene). However, the long chain branched linear low density polyethylene used in the present invention is different from the LLDPE and LDPE in the prior art in the content of at least Mw / Mn, amorphous component amount and long chain branch. That is, the predetermined long-chain branched straight-chain low density polyethylene of the present invention satisfies all of the following conditions (1) to (3).

(1) the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography is 7.5 to 15.0,

(2) the amorphous component amount measured by the temperature rising fractionation method is 1 to 4% by weight, and

(3) the number of branches having 8 or more carbon atoms, as measured by ¹³ C-NMR, is 1.5 to 5.0 per 1,000 carbon atoms.

The long chain branched low density polyethylene (B1) in the present invention has a weight average molecular weight Mw in terms of polystyrene and a ratio Mw / Mn (molecular weight distribution) of the number average molecular weight Mn measured by gel permeation chromatography (GPC) 15.0. This value is preferably 8.5 to 14.5, more preferably 9.5 to 13.5. By using the long-chain branched low density polyethylene (B1) having such a molecular weight distribution, the multilayered sealant film of the present invention is excellent in optical characteristics (haze and image clarity), and the film peeling occurs at the edge of the heat- It is possible to obtain the advantage of expressing the ease of opening.

The long-chain branched linear low density polyethylene (B1) in the present invention preferably has a weight average molecular weight Mw in terms of polystyrene measured by GPC of 80,000 to 150,000, more preferably 90,000 to 140,000.

The long-chain branched linear low-density polyethylene (B1) of the present invention has an amorphous component amount of 1 to 4% by weight measured by an elevated temperature fractionation method.

The temperature rising elution fractionation method is a method in which a solution obtained by dissolving a polymer sample at a high temperature in a predetermined solvent is supplied to a column of TREF (Temperature Rising Elution Fractionation), followed by cooling to precipitate and adsorb a polymer sample in the column, , And a method of analyzing the fraction to be eluted (fraction). In the present invention, the column after the sample supply is cooled to 0 deg. C, the supply of the solvent is started, the oil fraction eluted during the period in which the column temperature is maintained at 0 deg. C is set as the amorphous component, The ratio is evaluated as the amorphous component amount. The amorphous component amount of the long-chain branched straight-chain low-density polyethylene (B1) is preferably 1.5 to 3.0% by weight.

Such a temperature rising dissolution fractionation method can be carried out using a suitable temperature rising fractionation (TREF) apparatus such as a TREF apparatus special type of Senshu Chemical Co., Ltd., for example.

The use of the long chain linear low density polyethylene (B1) having such crystallinity as described above provides excellent optical characteristics (haze, image clarity), and exhibits easiness of opening without peeling of the film at the edge of the heat seal portion . ≪ / RTI >

Long-chain branching in the present invention linear low-density polyethylene (B1) is ^{1 3} C-NMR at a number of carbon atoms of 8 or more branches per 1000 carbon atoms as determined by 1.5 to 5.0 atoms. This value is preferably 2.0 to 5.0, more preferably 2.5 to 4.5. By using the long-chain branched low-density polyethylene (B1) having a long chain branch having such a long chain branch, the multilayered film of the present invention can stably exhibit a high fusing seal strength regardless of the ambient environment such as temperature, humidity, Can be expressed, which is preferable.

The LLDPE in the prior art is predominant when the number of carbon atoms in the branch is 6 or less and even if a branch having 8 or more carbon atoms is present, the amount thereof is small and is usually 1 or less and usually 2 or less per 1,000 carbon atoms .

On the other hand, LDPE has a component which is detected as a branch having 8 or more carbon atoms by ¹³ C-NMR more than the above range in the present invention.

Therefore, long-chain branched low-density polyethylene (B1) in the present invention can be distinguished from LLDPE and LDPE in the prior art by the amount of branching of not less than 8 carbon atoms as measured by ¹³ C-NMR.

The method for measuring the amount of long chain branch in the present invention will be described below. Here, C ₈ branch (1-decene structure) is taken as a branch of long chain branched low density polyethylene (B1) and C ₆ branch (1-octene structure) is taken as a branch of LLDPE in the prior art, respectively.

The methylene carbon present in the main chain of the polyethylene was observed at ¹³ C-NMR at chemical shift 隆 = 30 ppm. The methyl carbon at the branching end appears at both the C ₈ branch and the C ₆ branch at chemical shift δ = 14.06 ppm. However, the chemical shifts of the second and third methylene carbons from the branched end are different in the C ₈ branch and the C ₆ branch as shown in Table 1 below.

In the present specification, attention is focused on the second methylene carbon from the branching end thereof to determine whether the number of carbon atoms in the branch is 8 or more by the chemical shift.

In the actual calculation, the area of the peak appearing at the chemical shift? = 22.87 ppm is evaluated as a relative value to the area of the peak at the chemical shift? = 30 ppm assigned to the methylene carbon of the main chain.

The above ¹³ C-NMR measurement can be performed under the following conditions using a suitable nuclear magnetic resonance analyzer such as the type " JNM-ECS400 ", manufactured by Nippon Denshi Co.,

Solvent: Mixed solvent of trichlorobenzene / medium benzene (75/25 by volume)

Sample concentration: 80 mg / 2.5 mL solution

Measurement mode: 1H-full decoupling

Measuring temperature: 120 ° C

Pulse width: 90 degree pulse

Pulse repetition time: 9 seconds

Accumulated count: 9,000 times

The content of the long chain branch in the present specification is,

The peak area of the second carbon from the end of the C ₈ branch (chemical shift 隆 = 22.87 ppm)

Is expressed as a relative value when the peak area of the methylene carbon (chemical shift? = 30 ppm) constituting the polymer chain is 1,000. Unit is (thousand / 1,000C).

For reference, various parameters as described above are compared for representative polyethylene in Table 2 below.

The long-chain branched linear low-density polyethylene (B1) in the present invention may be synthesized by any method as long as it satisfies the above-mentioned requirements. For example, by using a known Ziegler Natta catalyst, preferably with a suitable donor compound; A method using a Phillips catalyst; A method using a metallocene catalyst or the like. Among them, the method using a metallocene catalyst is preferable in that a polymer having the above properties can be easily obtained.

The metallocene catalyst is a catalyst comprising a metallocene-type transition metal compound having at least one, preferably two, substituted or unsubstituted cyclopentadienyl ligands and a cocatalyst. As the co-catalyst, for example, an organoaluminum compound; A complex of an organic boron compound and a cation; Ion-exchangeable silicates, and the like, and at least one selected from these can be used. The metallocene-based catalyst may be supported on a suitable inorganic substance. The metallocene catalysts are already known in the art, and those skilled in the art can appropriately select and use a suitable metallocene catalyst according to the purpose.

[Other Resins]

The resin constituting the intermediate layer (B) may contain only the long-chain branched straight-chain low-density polyethylene (B1) or may contain other resins in addition to the long-chain branched straight-chain low-density polyethylene (B1).

Examples of the other resin used herein include a polyethylene resin (except for the long chain branched low density polyethylene (B1) described above), a polypropylene resin, and a polybutene resin.

Examples of the polyethylene-based resin include LLDPE (straight chain low density polyethylene, except for the long chain branched low density polyethylene (B1) described above) and LDPE (low density polyethylene).

-LLDPE-

The LLDPE is an LLDPE other than the long chain branched linear low density polyethylene (B1) described above, and LLDPE in the prior art can be used. The LLDPE is preferably a copolymer of ethylene and an? -Olefin other than ethylene. The? -Olefin in this case is preferably an? -Olefin having 3 to 12 carbon atoms, and specific examples thereof include propylene, 1-butene, 1-pentene, 1-hexene, - pentene, 1-decene, 1-dodecene, and the like.

In order to classify this LLDPE with long chain branched low density polyethylene above, for example, the following parameters can be exemplified.

The molecular weight distribution Mw / Mn in terms of polystyrene measured by GPC is preferably 1.5 to 5.0,

It is preferable that the amount of the amorphous component measured by the temperature-rising elution fractionation method is 1 to 5% by weight, and

The number of branches having 8 or more carbon atoms as measured by < ¹³ > C-NMR is preferably less than 5.0 per 1,000 carbon atoms, more preferably less than 3.0. The measurement method of these parameters is the same as in the case of the long-chain branched straight-chain low density polyethylene (B1).

The LLDPE preferably has an MFR of 0.5 to 20 g / 10 min measured at 190 占 폚 under a load of 2.16 kg in accordance with JIS K 7210.

Such LLDPE can be obtained by a known method. For example, it can be synthesized by using a chromium-based catalyst alone, or a catalyst system using a chromium-based catalyst and a Ziegler-Natta catalyst in combination.

-LDPE-

The LDPE is not particularly limited, and LDPE in the prior art can be used.

The LDPE preferably has an MFR of 0.1 to 50 g / 10 min measured at 190 占 폚 under a load of 2.16 kg in accordance with JIS K7210.

- Polypropylene resin -

Examples of the polypropylene resin include a homopolymer of propylene and a copolymer of propylene and a copolymerizable component. As the copolymerization component, ethylene and alpha -olefin are preferable, and examples thereof include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, -Decene, 4-methyl-1-pentene, and the like, and at least one selected from these may be used. The proportion of the copolymerizable component in the polypropylene resin is preferably 10 mol% or less, more preferably 5 mol% or less, and further preferably 3 mol% or less.

The MFR of the polypropylene-based resin measured at 230 ° C under a load of 2.16 kg in accordance with JIS K 7210 is preferably 0.5 to 50 g / 10 min.

- Polybutene resin -

As the polybutene resin, the same resins as the polybutene resin (A1) contained in the laminate layer (A) constituting the multilayered sealant film of the present invention can be used.

[Amount of long-chain branched linear low-density polyethylene (B1)

The amount of the long chain branched low density polyethylene (B1) in the intermediate layer (B) constituting the multilayered sealant film of the present invention is preferably at least 50 parts by weight based on 100 parts by weight of the total amount of the resins constituting the intermediate layer (B) And preferably 60 parts by weight or more. By adjusting the amount of the long chain branched low density polyethylene (B1) to be in the above range, it is possible to obtain a film having excellent optical characteristics (haze and image clarity) and showing ease of opening without peeling of the film at the edge of the heat- Can be obtained.

[Other components]

The intermediate layer (B) may contain, in addition to the above-mentioned resin, a resin such as a petroleum resin, a terpene resin, a rosin, an anti-blocking agent, an antioxidant, a light stabilizer, a lubricant, an antistatic agent, , Antimicrobial agents, and the like.

[Manufacturing method of intermediate layer (B)] [

The intermediate layer (B) can be obtained by melt-mixing the above-mentioned resin and other components to be used as required, and film-forming the mixture. For example, an extruder or the like may be used for the melt mixing, and a T-die or the like may be used for the film formation.

The thickness of the intermediate layer (B) is not particularly limited as long as it does not impair the adhesion to the laminate layer (A) and / or the heat seal layer (C) and the cohesive failure performance of the laminate layer (A). Preferably about 3 to 50 mu m, and more preferably about 4 to 45 mu m. If the intermediate layer (B) is too thin, the adhesion to the laminate layer (A) and / or the heat seal layer (C) may be insufficient. On the other hand, if the thickness of the intermediate layer (B) is excessively large, the optical properties such as transparency and image clarity may be impaired, besides, economical efficiency is lowered and the weight of the resulting packaging bag is increased.

≪ Heat Sealing Layer (C) >

The sheet seal layer (C) is a layer having a function of sealing the package to be obtained by thermocompression of opposing heat seal layers (C) when the package bag is heat sealed.

The heat seal layer (C) contains the propylene random copolymer (C1).

[Propylene random copolymer (C1)]

Examples of the propylene random copolymer (C1) used in the sealing layer (C) include a copolymer of propylene and an? -Olefin. As the? -Olefin,? -Olefins having 2 or 4 carbon atoms are preferable, and specific examples thereof include ethylene, 1-butene, 1-pentene, 1-hexene, . Particularly preferred are propylene-ethylene random copolymers or propylene-ethylene-butene random copolymers.

The content of the propylene unit in the propylene random copolymer (C1) is preferably 80 to 99% by weight, and more preferably 85 to 98% by weight, based on 100% by weight of the total amount of the copolymer.

The melting point of the propylene random copolymer (C1) is not particularly limited, but it is preferably within the range of 115 to 155 캜, and more preferably in the range of 120 to 150 캜, from the viewpoint of obtaining good low- desirable. When the melting point of the propylene random copolymer (C1) is too low, the heat-sealability of the heat-sealed portion may be deteriorated. On the other hand, when the melting point is too high, the low-temperature heat sealability may be insufficient.

The MFR (230 DEG C) of the propylene random copolymer (C1) is not particularly limited, but is preferably 0.5 to 50.0 g / 10 min, more preferably 1.0 to 30.0 g / 10 min Do.

[Other Resins]

The resin constituting the heat seal layer (C) may be formed solely of the propylene random copolymer (C1), or may contain other resins in addition to the propylene random copolymer (C1). Examples of other resins used herein include, besides the above-described resins of the same kind as the polybutene resin, LLDPE and LDPE described above, other thermoplastic resins.

The amount of other resins used in the resin constituting the heat seal layer (C) is preferably 10 parts by weight or less when the total amount of the resin is 100 parts by weight. That is, the amount of the propylene random copolymer (C1) to be used is preferably 90 parts by weight or more.

[Other components]

The heat seal layer (C) may contain, in addition to the above-mentioned resin, a resin such as petroleum resin, terpene resin, rosin, anti-blocking agent, antioxidant, light stabilizer, lubricant, antistatic agent, antifogging agent, , A nucleating agent, an antimicrobial agent, and the like.

[Manufacturing method of heat seal layer (C)] [

The heat seal layer (C) can be obtained by melting and mixing the above resin and other components to be used, if necessary, and forming the film into a film. For example, an extruder or the like may be used for the melt mixing, and a T-die or the like may be used for the film formation.

The thickness of the heat seal layer (C) is not particularly limited as long as it does not impair adhesion between the heat seal layers (C). Preferably about 1.5 to 50 mu m, and more preferably about 30 mu m or less. If the heat seal layer (C) is too thin, the heat sealability may be insufficient. On the other hand, if the heat seal layer (C) is too thick, the economical efficiency is low and the weight of the resulting packaging bag is increased.

<Multilayered Sealant Film and Method for Manufacturing the Same>

The multilayered sealant film of the present invention is constituted by laminating the laminate layer (A), the intermediate layer (B) and the heat seal layer (C) in this order. The intermediate layer may be a single layer, or may be composed of multiple layers having the same function or multiple layers having different functions.

Each of the layers in the multilayered sealant film is preferably laminated under the conditions of non-stretching or low stretching, and it is particularly preferable that lamination is carried out in a substantially non-stretched state.

Each layer in the multilayer sealant film is preferably laminated by coextrusion.

The film forming method for each layer is preferably a non-stretch method. As a typical method, for example, an extrusion molding method using T die, an inflation molding method using a ring dice, and the like, and a co-extrusion method using a T die or a multi-manifold method is suitable.

As to the extrusion molding method using the T die, more specifically, for example,

A resin constituting each layer or a melt of the resin composition is extruded from each extruder by a T-die method,

A method of winding after cooling by a temperature-adjustable roll;

A method of winding after cooling by a temperature adjustable water tank;

A method of cooling by air cooling and then winding;

A method of cooling after cooling by water cooling method

And the like.

The multi-layered sealant film obtained by these methods is a low-stretch film or a substantially non-stretchy film which is stretched slightly by stretching or the like at the time of winding.

The thickness of the multilayered sealant film of the present invention may be, for example, 10 to 150 mu m, preferably 15 to 120 mu m.

The laminate layer (A), the intermediate layer (B), and the heat seal layer (C) may be subjected to appropriate surface treatment such as corona discharge treatment and flame treatment prior to lamination for the purpose of improving adhesion of each layer. The surface to be subjected to the above-mentioned surface treatment is not particularly limited, and may be either one-side treatment or two-side treatment.

<Packing materials>

The above-mentioned multilayered sealant film of the present invention can be used as a packaging material by attaching the laminate layer (A) to the substrate film as an attachment surface.

1 shows the multilayered sealant film 1 of the present invention including the laminate layer A, the intermediate layer B and the heat seal layer C as a bonding surface of the packaging material 2 attached to the base film 3 with the laminate layer A as a bonding surface Sectional view is shown.

The material constituting the base film can be appropriately selected in accordance with the strength, hardness and the like required for the packaging material. The base film may have a layer containing at least one resin selected from the group including, for example, a polypropylene resin, a polyethylene resin, a polyethylene terephthalate resin and a polyamide resin, or a layer containing a metal . Specific examples of the base film include biaxially oriented polyester film, biaxially oriented polyamide film, biaxially oriented polypropylene film and the like;

A biaxially oriented polyester film, a biaxially oriented polyamide film, a biaxially oriented polypropylene film, and the like;

A biaxially oriented polyester film, a biaxially oriented polyamide film, a biaxially oriented polypropylene film and the like, and a laminated film of another thermoplastic resin film

And the like.

The thickness of the substrate can be appropriately set according to the use of the packaging material, and can be, for example, about 10 to 300 mu m. The base material may be printed indicating the name of the contents, the name of the manufacturer, and the like.

The surface of the substrate on the side where the multilayered sealant film of the present invention is laminated may be subjected to appropriate surface treatment such as corona discharge treatment or flame treatment for the purpose of improving the adhesion.

The multilayered sealant film of the present invention is attached to the base film with the laminate layer (A) as an attachment surface. As a specific attachment method, for example,

A method in which the multilayered sealant film of the present invention is loaded on one side of the substrate so that the laminate layer (A) is in contact with the other side, and both are thermocompression bonded;

A method in which a resin or a resin composition constituting the laminate layer (A), the intermediate layer (B) and the heat seal layer (C) is co-extruded and laminated on one side of the substrate;

(A) side of the multilayered sealant film of the present invention is adhered with an adhesive

And the like.

When the base material and the multilayered sealant film are thermocompression bonded, the thermocompression bonding temperature is preferably set to be equal to or higher than the softening temperature of the laminate layer (A), the thermocompression pressure is preferably about 0.1 MPa or more, 5.0 seconds is preferable. As the adhesive, for example, a molten resin (for example, molten polyethylene resin) or the like can be used, and a commercially available adhesive may be used. Examples of the application method of the adhesive include transfer means such as gravure, gravure reverse, offset, and the like; A scraping means such as a bar and a comma bar, and the like.

<Packing bag and sealed package>

The packaging material obtained as described above is processed into a bag shape having an opening portion with the heat seal layer C as an inner side, whereby a packing bag can be obtained. Specifically, the packaging material may be folded to an appropriate size with the heat seal layer C inward, and the end portion may be heat-sealed to form a bag. The heat seal temperature is preferably set to a temperature at which the heat seal layers C can be thermocompression bonded to each other, and can be, for example, about 100 to 200 DEG C. The heat seal pressure may be, for example, about 0.1 to 1.0 MPa, and the heat seal time may be about 0.5 to 5.0 seconds, for example.

The packing bag manufactured using the multilayered sealant film of the present invention is excellent in transparency and image clarity even after heat sealing the heat seal layer (C). The transparency of the packaging material after heat sealing the heat seal layer (C) can be, for example, 10% or less, preferably 8% or less,

The image clarity can be, for example, 55% or more, and preferably 65% or more.

After the contents are stored in the packaging bag obtained as described above, the sealed package can be obtained by heat-sealing the opposing heat-seal layers (C) in the openings. The heat sealing conditions are the same as those for producing the packaging bag.

2 shows a multilayer sealant film 1 and a base film 3 of the present invention which are packed in a sealed package 1 enclosed with a heat seal part 4 after the contents 6 are contained and then heat- A schematic illustration of the sieve (5) is shown.

The package body is provided with two film surfaces opposed to each other in the vicinity of the heat-sealed portion with the fingertips of the left and right hands, and is stretched in a direction perpendicular to the film surface and in a direction in which the two films are spaced apart, It can be opened. This opening is one of the characteristics of the present invention in that cohesive failure and delamination are performed together. That is, at the beginning of the opening, the closure of the laminate layer (A) results in clogging of the opening, and thereafter the transition to the delamination between the heat seal layer (C) and the intermediate layer (B) With such a mechanism, the sealed package manufactured using the multilayered sealant film of the present invention can be easily opened and opened easily.

3 is a schematic explanatory view for explaining a mechanism at the time of opening the heat-sealed portion of the sealed package. The heat seal portion is pulled in two directions indicated by the arrows at the time of opening so that the interlayer delamination of the heat seal layer C and the intermediate layer B progresses accompanied by the cohesive failure of the laminate layer (A) .

Here, by making the heat seal conditions extremely severe (for example, high temperature, high pressure or long time), the heat seal layers C are more firmly adhered to each other, but the laminate layers A and The state and properties of the intermediate layer B are not significantly changed. Therefore, even when the heat seal condition is changed, the cohesive failure of the laminate layer (A) and the force required for delamination between the heat seal layer (C) and the intermediate layer (B) are kept substantially constant. Therefore, the package can stably exhibit a smooth opening-and-opening characteristic easily regardless of the heat sealing condition.

The opening strength of the sealed package may be, for example, 40 N / bag or less, preferably 10 to 40 N / bag, and more preferably 15 to 35 N / bag. The burst strength, which indicates the sealing property of the package, can be 10 ㎪ or more, and preferably 15 ㎪ or more, for example.

Example

Hereinafter, the present invention will be described by way of examples and comparative examples, but the present invention is not limited to these examples. The physical properties of the resin and the film were measured as follows.

(1) MFR

According to JIS K6758, MFR was measured at 230 占 폚 for polypropylene and 190 占 폚 for polybutene and polyethylene.

(2) Melting point

Approximately 5 mg of the resin sample was quenched and sealed in an aluminum pan and mounted on a differential scanning calorimeter (Seiko Instruments Inc., type "SSC / 5200"), and the temperature was raised to 230 ° C in a stream of nitrogen of 20 mL / , Maintained at this temperature for 10 minutes, cooled to -10 占 폚 at a cooling rate of 10 占 폚 / min, and subsequently heated to 210 占 폚 at a heating rate of 10 占 폚 / min. The peak temperature was taken as the melting point.

(3) Transparency

As an index of transparency, transparency was measured according to JIS K7136 using a haze meter (NDH5000) manufactured by Nippon Denshoku Kogyo K.K.

(4) Phase definition

The slit width of the optical comb was set to 0.125 mm in accordance with JIS K7105 using an image forming apparatus (ICM-IDP) manufactured by Suga Shikenki Co., Ltd. to measure the image clarity. .

(5) Opening strength

The opposing surface spaced 30 mm from the top of the bag-sealed bag inlet of the packaging bag 4 was held by a chuck of a tensile tester and pulled back at a tensile speed of 500 mm / min to open the packaging bag 4, The strength was measured. The measurement was carried out ten times, and the average value was regarded as the opening strength.

(6) Film tear during opening

The opposing surfaces spaced 30 mm from the top of the heat sealed bag inlet of the sealed package 5 are held by hand and pulled in opposite directions with a strong force to open the sealed package 5, And the following judgment was made.

Criteria for judging film breakage at the time of opening

○: Good (film was not torn at the time of opening)

X: Bad (film tears at the time of opening)

(7) Peeling appearance at the time of opening (peeling)

When the bag is opened by holding the opposing surface spaced 30 mm from the upper portion of the heat sealed bag inlet by hand and pulling the bag in a reverse direction with a strong force to open the bag, the film is not broken along the boundary between the heat seal portion and the non- , The state of being peeled off into a micro-part was visually confirmed, and the following judgment was made.

Criteria for judging appearance of peeled part

○: Good (no peeling occurred)

X: Bad (peeling occurred)

(8) Bursting strength

Using a Sungakusha tear strength meter 305-BP, 1.0 L / min of air was blown into the sealed package 5, and the maximum pressure at the time of rupture was measured.

&Lt; Resin used &

PB1: polybutene homopolymer (BL4000 manufactured by Mitsui Chemicals, Inc., density 0.915 g / cm3, melting point 112 占 폚, MFR 1.8 g / 10 min)

PB2: 1-butene propylene random copolymer (BL2481, Mitsui Chemicals, Inc., density 0.900 g / cm3, melting point 75 占 폚, MFR 4.0 g / 10 min, butene content 79.2 parts by weight)

LLDPE1: linear low density polyethylene (Ube Maruzen Polyethylene 4040FC, density 0.937 g / cm3, melting point 126 占 폚, MFR 3.5 g / 10 min)

LLDPE2: linear low density polyethylene (CW8003 made by Sumitomo Chemical Co., Ltd., density 0.912 g / cm3, melting point 110 占 폚, MFR 8.0 g / 10 min)

LDPE1: low density polyethylene (Z372, Ube Maruzen Polyethylene, density 0.934 g / cm3, melting point 118 占 폚, MFR 5.0 g / 10 min)

LDPE2: low density polyethylene (Z322, UMBERZEN POLYETHYLENE CO., LTD., Density 0.933 g / cm3, melting point 119 占 폚, MFR 1.0 g / 10 min)

LDPE3: low density polyethylene (L705, manufactured by Sumitomo Chemical Co., Ltd., density 0.919 g / cm3, melting point 107 deg. C, MFR 7.0 g / 10 min)

Long chain branch LLDPE1: (CU7004 made by Sumitomo Chemical Co., Ltd., melting point 108 占 폚, MFR 3.0 g / 10 min, Mw / Mn 11.9, density 0.924 g / cm3 amorphous component 2.5 weight% C)

MFR 0.9 g / 10 min, Mw / Mn 9.6, amorphous component 2.2 wt%) having a melting point of 106 占 폚 and a long-chain branch LLDPE2: (GT140 manufactured by Sumitomo Chemical Co.,

MFR 0.4 g / 10 min, Mw / Mn 13.2, amorphous component 2.2 wt%) of long chain branch LLDPE 3: (GH051 manufactured by Sumitomo Chemical Co.,

PP1: propylene-ethylene random copolymer (FW3GT manufactured by Japan Polypropylene, melting point: 148 占 폚, MFR: 7.0 g / 10 min)

R-PP1: propylene-ethylene-1-butene random copolymer (F794NV, Prime Polymer Co., melting point: 134 캜, MFR: 5.0 g / 10 min)

R-PP2: propylene-ethylene random copolymer (WFX4TA, melting point 126 ° C, MFR 7.0 g / 10 min, manufactured by Japan Polypropylene Co., Ltd.)

The content of the long chain branch shown in the column "long chain branch" is the number of branches having 8 or more carbon atoms per 1,000 carbon atoms calculated from the result of ¹³ C-NMR measurement according to the following equation (1) under the following conditions.

[ ¹³ C-NMR measurement conditions]

Measurement apparatus: type "JNM-ECS400", manufactured by Nihon Denshi Co., Ltd.

Solvent: Mixed solvent of trichlorobenzene / medium benzene (75/25 by volume)

Sample concentration: 80 mg / 2.5 mL solution

Measurement mode: 1H-full decoupling

Measuring temperature: 120 ° C

Pulse width: 90 degree pulse

Pulse repetition time: 9 seconds

Accumulated count: 9,000 times

Long branch branch content (number / 1000C) = A / B × 1,000 (1)

(In the formula (1), A is the peak area of the chemical shift 隆 = 22.87 ppm,

B is the peak area of chemical shift? = 30 ppm)

The content of the amorphous component was measured by the temperature rising elution fractionation method under the following conditions: the column after the sample supply was cooled to 0 캜, the supply of the solvent was started, and the oil fraction eluted during the period in which the column temperature was maintained at 0 캜, Of the total weight of the composition.

[Conditions for performing the temperature-rising elution fractionation method]

Measuring device: Senshu Kagaku Co., Ltd., model number "TREF device special type"

Column: inner diameter 10 mm x 300 mm

Filler: Chromosolve P NAW (30 / 60mesh, manufactured by GEI Scientific Co., Ltd.)

Sample solution concentration: 5 mg / mL

Sample solution injection amount: 2 mL

Solvent: Orthodichlorobenzene

Flow rate: 1 mL / min

Sample injection temperature: 140 ℃

Deceleration rate: 5 ℃ / h

Cooling temperature: 10 ℃

Holding time at the temperature reached for cooling: 30 minutes

Heating rate: 5 ° C / h

Detector: Infrared detector

Measured wave number: 3.42 탆

Example 1

&Lt; Preparation of multi-layered sealant film &

Three single-layer extruders each having a screw diameter of 75 mm for the middle layer (B layer) and two single-screw extruders having a screw diameter of 50 mm for both outer layers (A layer and C layer) Using the T-die type film-forming apparatus of the constitution, the resin was supplied to each extruder as follows.

Extruder for layer A: 35 parts by weight of PB1, 50 parts by weight of LLDPE1 and 15 parts by weight of LDPE1

Extruder for layer B: long-chain branch LLDPE1

Extruder for C-layer: R-PP1

The resin was melted at any one of the three extruders at a resin temperature of 230 DEG C and a retention time of 1 minute and was fed from each T die having a die lip gap of 1.5 mm by a co- , And the three layers were combined to obtain a multilayered film through a cooling roll at 30 캜. The multi-layer film had a three-layer structure and had a total thickness of 20 mu m, and the three layers had a thickness of 4 mu m for the A layer, 11 mu m for the B layer and 5 mu m for the C layer. (A) / intermediate layer (B) / heat seal layer (C) by winding a corona discharge treatment on the surface of the multilayered film obtained above on the side of the A layer side to have a wetting index of 40 mN / ) Was obtained. &Lt; tb &gt; &lt; TABLE &gt;

<Manufacture of packing bag>

Corona discharge treatment was performed on one surface of a biaxially stretched polyester film (trade name "E2001", thickness 12 μm) of Futamura Kagaku Co., Ltd. as a base film so that the wetting index was 40 mN / m.

The corona discharge treated surface of the substrate film and the corona discharge treated surface (laminate layer (A) surface) of the multilayered sealant film obtained above were bonded by a urethane adhesive to obtain a packaging material.

Subsequently, the heat seal layer (C) of each of the packaging materials was heat sealed at a heat seal width of 15 mm and a heat seal temperature of 140 캜 using a vertical pillow packing machine (product name "TWX1N" manufactured by Tokyo Kikai Seisakusho Co., Ltd.) , The time was 0.6 seconds, and the pressure was 0.5 MPa (bag production condition: A), thereby obtaining a pillow packing bag having a length of 200 mm and a width of 130 mm.

<Evaluation of packaging bag>

The packaging bags obtained above were evaluated in the above (3) to (8).

The evaluation results are shown in Table 3.

Examples 2 to 14 and Comparative Examples 1 to 15

A multilayer film and a packaging bag were produced in the same manner as in Example 1 except that the type and amount of the resin to be fed to the extruder for each layer and the thickness of each layer were changed as shown in Table 3 , Respectively. The bag production condition B of Example 5 is a heat seal width of 15 mm, a heat seal temperature of 200 캜, a time of 1.0 second, and a pressure of 1.0 MPa.

The evaluation results are shown in Table 3.

[Effects of the Invention]

The packaging material produced by using the multilayered sealant film of the present invention gives a sealable package which can be easily opened without depending on the heat seal condition. Therefore, by appropriately setting the conditions for heat sealing the packaging material, it is possible to obtain a sealed package having both high heat sealing strength and ease of opening. Specifically, at the start of the opening of the film from the middle-layer sealed portion (the portion with high sealing strength) of the film in the pillow package, in the middle-layer sealed portion, the interface between the heat- The interlayer delamination does not function and the heat seal layer and the intermediate layer are destroyed, so that the delamination failure mode of the laminate layer ensures reliable delamination. Opening of the backside of the middle-layered sealing portion reduces the peeling strength between the intermediate layer and the heat-sealing layer, rather than the cohesive failure strength of the laminated layer, so that the mode is shifted to the interlayer peeling mode and opened. It is possible. In addition, when the bag is opened, the laminate layer does not undergo the cohesion failure mode, so that peeling of the film between the intermediate layer and the heat-seal layer does not occur at the edge of the heat-sealed portion. Furthermore, since the long-chain branched low-density polyethylene (B1) is used for the intermediate layer and the low-density polyethylene resin having a specific density for the laminate layer is used, the multilayered sealant film of the present invention is excellent in optical characteristics (haze, image clarity) For example, it is very suitable as a raw material for packaging materials for sealing, preserving and trading paper, industrial parts such as food, medical care, miscellaneous goods, books and cards, and the like.

Claims (7)

A laminate layer (A) as an outermost layer,
At least one intermediate layer (B)
And the heat seal layer (C), which is the outermost layer,
(A) side as an attachment surface to be adhered to a substrate film, wherein the multilayer sealant film is a multilayer sealant film,
Wherein the laminate layer (A)
30 to 70 parts by weight of a polybutene resin (A1)
20 to 60 parts by weight of a linear low-density polyethylene resin (A2)
(A1), a linear low density polyethylene resin (A2) and a low density polyethylene resin (A3), and a low density polyethylene resin (A3) having a density of 0.930 g / cm3 or more. Is 100 parts by weight,
Wherein at least one layer of the intermediate layer (B) of the at least one layer comprises a long-chain branched linear low density polyethylene (B1) having the following characteristics (1) to (3), the total amount of the resins constituting the intermediate layer By weight and 50 to 100 parts by weight,
Wherein the heat-seal layer (C) comprises a resin containing a propylene-based random copolymer.
(1) the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography is 7.5 to 15.0,
(2) the amorphous component amount measured by the temperature rising fractionation method is 1 to 4% by weight, and
(3) the number of branches having 8 or more carbon atoms measured by ¹³ C-NMR is 1.5 to 5.0 per 1,000 carbon atoms. The laminate according to claim 1, wherein the thickness of the laminate layer (A) is 1.5 to 50 탆,
The thickness of the intermediate layer (B) is 5 to 100 mu m, and
Wherein the laminate layer (A), the intermediate layer (B), and the heat seal layer (C) are laminated by a co-extrusion method. A packaging material obtained by attaching the multilayered sealant film according to claim 1 or 2 on a base film with the laminate layer (A) as a bonding surface. The laminate of claim 3, wherein the base film is a layer comprising at least one resin selected from the group consisting of a polypropylene resin, a polyethylene resin, a polyethylene terephthalate resin and a polyamide resin, Layer. A pillow packaging bag made from the packaging material of claim 3 or 4. A sealed package obtained by housing contents in the pillow packaging bag according to claim 5, and heat sealing the opening of the packaging bag. The sealed package according to claim 6, wherein the burst strength is 10 K Pa or more, the transparency is 10% or less, the image clarity is 55% or more, and the opening strength to open the sealed package is 40 N / bag or less.

Images