JP3132373B2 - Multilayer film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a multilayer film comprising at least two layers. More specifically, the present invention relates to a polyethylene-based multilayer film having at least two layers, which is excellent in optical properties such as transparency and appearance, and has remarkably improved antiblocking property.

[0002]

2. Description of the Related Art At present, packaging materials used for packaging foods, medicines, miscellaneous goods, industrial goods and the like are very diversified, but most of them are polyethylene, polypropylene, ethylene-vinyl acetate copolymer and ethylene. A polyolefin-based resin such as an α-olefin copolymer is used as a heat seal layer. These resin layers are usually used by being laminated with another appropriate base film, and when forming a laminated film, for example, lamination such as dry lamination, wet lamination, sand lamination, hot melt lamination, etc. A known technique such as an extrusion method, an extrusion lamination method, and a combination thereof is employed. Among these, it is known that the dry lamination method can obtain a strong adhesive strength.

[0003] In general, for packaging materials, to protect the contents, mechanical strength such as heat sealing strength, impact strength, tensile strength, and tear strength, barrier functions such as water vapor barrier properties and gas barrier properties, and heat resistance. , Thermal function such as cold resistance,
Furthermore, many functions are required, such as anti-blocking properties, low-temperature sealing properties, hot tack properties, stiffness, slipperiness, and other packaging suitability. In the case of a laminated film, these properties vary greatly depending on the choice of the base material, but similarly, the function of the packaging material also varies greatly depending on the choice of the resin used for the sealant layer. When packaging at a high speed, the film needs to have enough stiffness to withstand high-speed running, and a film that can be heat-sealed at a low temperature is required to enable high-speed heat sealing.

[0004] Polyethylene films such as high-pressure low-density polyethylene, ethylene-vinyl acetate copolymer and ethylene-α-olefin copolymer can be heat-sealed at a low temperature and have high sealing strength. It is widely used for packaging foods such as mustard and miso, as well as liquid detergents and liquid chemicals. However, polyethylene films have inferior anti-blocking properties, so when they are stacked during storage of bag-made products, etc., the films cause blocking with each other, significantly impairing the workability at the time of filling the contents, or opening property. It has the disadvantage that it cannot be used when it is very bad.

Therefore, conventionally, an anti-blocking agent such as silica and zeolite and a lubricant such as organic amide are blended in the film. However, when a large amount of an anti-blocking agent is added to improve the anti-blocking property, the transparency of the film surface is reduced, and a problem occurs in appearance. In addition, there arises a problem that the scratches on the film surface are deteriorated due to friction between the films during transportation or the like.

On the other hand, when a considerable amount of a lubricant is used in combination with an anti-blocking agent in order to improve the anti-blocking property, there is a problem that a guide roll is contaminated during bag making or in a printing process, and the so-called secondary workability is poor. are doing. Also,
These applications are often laminated by a dry lamination method because high adhesive performance is required, but depending on the type of adhesive used at the time of dry lamination, after lamination, the adhesive is usually cured for 30 to 30 minutes. It is known that during aging performed at 60 ° C. for about 1 to 3 days, the lubricant component migrates to the adhesive layer and does not show sufficient slipping or anti-blocking properties.

[0007] Dry laminating adhesives are composed of a main component and a curing agent. The main components are roughly classified into ether type and ester type, and the adhesive using the ether type as the main component is excellent in initial adhesive strength and quick curing property. In addition, they are often used for polyethylene films because of their relatively low cost. However, since they are easily combined with a lubricant component and the above-mentioned troubles are likely to occur, they are characterized by heat resistance, and are mainly used for polypropylene films. In many cases, the mold must be used.
However, an adhesive mainly comprising an ester type is expensive and is inferior to an adhesive mainly comprising an ether type in terms of initial adhesive strength and quick-curing properties. From these points, in general, in order to improve the openability of bag-formed products, in addition to the combination of a lubricant and an anti-blocking agent, sprinkle and use starch such as corn as a main raw material during dry lamination processing and bag making. I have. However, there was a problem in the appearance of the product, such as the appearance of the starch powder as mold and foreign substances. In addition, Japanese Unexamined Patent Publication No.
Japanese Patent No. 312491 discloses that, in a laminated film in which a layer mainly composed of a polyethylene resin is composed of an A layer / B layer / C layer in order, an A layer is used for 100 parts by weight of the polyethylene resin and an unsaturated fatty acid amide 0 layer. 0.02 to 0.07 parts by weight and 0.05 to 1.00 parts by weight of fine particles. The C layer contains 0.02 to 0.07 parts by weight of unsaturated fatty acid amide, 0.01 to 0.20 parts by weight of a saturated fatty acid bisamide and an average particle size of 1
A polyethylene-based multilayer film containing 0.30 to 2.00 parts by weight of fine polymer particles having a decomposition temperature of 1 to 20 μm and a decomposition start temperature of 250 ° C. or higher is disclosed. However, since the polyethylene-based multilayer film has no density gradient in the polyethylene-based resin constituting the three layers, the lubricant easily bleeds to the surface of the laminating layer, and the blending of the lubricant into the laminating layer is indispensable. In addition, the adhesive strength to the substrate during dry lamination, the slipperiness, and the anti-blocking property cannot all be sufficiently satisfied.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a starch containing corn as a main raw material, which has been conventionally used in dry lamination, because of its excellent transparency, appearance and remarkable improvement in anti-blocking properties. An object of the present invention is to provide a multilayer film which can be used as a packaging film having a high opening property without using powder.

[0009]

Means for Solving the Problems As a result of diligent studies on such problems, the present inventors have found that a multilayer film having at least two or three layers has a specific density range,
These problems have been solved by laminating in a specific layer configuration using an ethylene-α-olefin copolymer having a specific range of the density difference, a specific antiblocking agent and a specific organic amide, and an excellent The present inventors have found that a multilayer film having remarkably excellent anti-blocking properties in addition to transparency and appearance can be obtained, thereby completing the present invention.

That is, the present invention comprises at least two layers: (a) the layer is composed of ethylene and an α-olefin having 3 to 12 carbon atoms, and has a density of 0.905 to 0.945 g / cm ³ ;
With respect to 100 parts by weight of an ethylene-α-olefin copolymer having a melt flow rate of 0.5 to 30 g / 10 minutes, an unsaturated fatty acid amide having a melting point of 65 ° C to 90 ° C is added to 0.0 parts by weight.
15 not or no content parts hereinafter to containing Yes, (b) layer consists of ethylene and 3 to 12 carbon atoms α- olefin, the density 0.900~0.940g / cm ^3,
With respect to 100 parts by weight of an ethylene-α-olefin copolymer having a melt flow rate of 0.5 to 30 g / 10 minutes, 0.01 to 0.20 parts by weight of an unsaturated fatty acid bisamide and a melting point of 65 ° C to 90 ° C. Unsaturated fatty acid amide 0.01 ~
0.20 parts by weight and a weight average particle diameter of 8 to 20 μ and a refractive index nD measured at 25 ° C. of 1.45 to 1.5
8, containing 0.2 to 2.0 parts by weight of an anti-blocking agent, wherein the density of the (a) layer and the (b) layer is (a)>
(B) and the difference in density is 0.005 g / cm
It is intended to provide a multilayer film characterized by being ³ or more.

The present invention also provides a multilayer film comprising, as an intermediate layer, ethylene and an α-olefin having 3 to 12 carbon atoms having a density of 0.90 between the (a) layer and the (b) layer.
0 to 0.945 g / cm ³ , melt flow rate 0.5
A layer (c) containing an ethylene-α-olefin copolymer having an ethylene-α-olefin copolymer content of up to 30 g / 10 min.
The density of the olefin copolymer is (a) layer ≧ (c) layer ≧
It is an object of the present invention to provide a multilayer film comprising at least three layers, which is the layer (b), and wherein the density difference between the layer (a) and the layer (b) is 0.005 g / cm ³ or more. Hereinafter, the present invention will be described in detail.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the ethylene-α-olefin copolymer used for the layers (a) and (b) constituting the multilayer film of the present invention, the α-olefin to be copolymerized with ethylene has 3 to 3 carbon atoms. 12 things. In particular,
Propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, heptene-1, octene-
1, nonene-1, decene-1, dodecene-1, and the like, and mixtures thereof. Among them, propylene, butene-1, 4-methylpentene-1, hexene-
C3 such as 1,4 methylhexene-1, octene-1, etc.
~ 8 alpha-olefins are preferred. Further, α-olefins such as butene-1 and hexene-1 are more preferred. The α-olefin content in the ethylene-α-olefin copolymer is preferably from 1 to 20 mol%.

(A) constituting the multilayer film of the present invention;
(B) In the production of the ethylene-α-olefin copolymer used for the layer, generally, ethylene and an α-olefin are used, and at least a transition metal-containing solid catalyst component and an organoaluminum compound are subjected to an ionic polymerization method. 30 to 300 ° C, normal pressure to 3
000 kg / cm ² , in the presence or absence of a solvent,
It is polymerized and manufactured under gas-solid, liquid-solid or homogeneous liquid phase.

Examples of the solid catalyst component containing a transition metal include titanium compounds and magnesium chloride compounds such as chromium oxide, molybdenum oxide, titanium trichloride, titanium tetrachloride, titanium tetrachloride-alkyl aluminum and titanium tetrachloride. Magnesium compound- (chlorinated) alkylaluminum compound. The organoaluminum compound is represented, for example, by the general formula R ′ _m AlX _3-m (where R ′ is a hydrocarbon group, X is a halogen, and 1 ≦ m ≦ 3), and (C ₂ H ₅₎ ) ₂ AlCl, (C ₄
H ₉ ) ₂ AlCl, (C ₆ H ₁₃ ) ₂ AlCl, (C ₂ H ₅ ) _1.
5 AlCl _1.5 , (C ₄ H ₉ ) _1.5 AlCl _1.5 , (C ₆
H ₁₃ ) _1.5 AlCl _1.5 , C ₂ H ₅ AlCl ₂ , C ₄ H ₉
AlCl ₂ , C ₆ H ₁₃ AlCl _{2 and the} like can be mentioned.

(A) Layer Constituting the Multilayer Film of the Invention
The ethylene-α-olefin copolymer used for
0.905 to 0.945 g / cm^Three, Melt flowre
0.5 to 30 g / 10 min. (A) the layer is
Unsaturated with a melting point of 65 to 90 ° C based on 100 parts by weight
The content of the fatty acid amide is 0.015 parts by weight or less.
(A) Layer is dry-laminated with other film base
In the case of lamination, the adhesive layer becomes an adhesive layer.
0.905g / cm^ThreeIf less than
(B)
Fatty acid amide and unsaturated fatty acid contained in the layer
Lubricant such as bisamide easily bleeds into layer (a)
This leads to a decrease in adhesive strength. On the other hand, 0.945
g / cm ^ThreeExceeds the limit, the flexibility of the resulting film is
Handling due to addition, impact strength and curl (warpage)
The easiness of the work decreases. Unsaturated fatty acid amide used in the present invention
Has a melting point of 65 to 90 ° C, and if the melting point is less than 65 ° C,
Anti-blocking of film not only after lamination but also before lamination
The sliding property is poor.
The improvement effect becomes insufficient. Here, the melting point is measured by DSC
The temperature was raised at a rate of 5 ° C./min in a nitrogen atmosphere using
It means the value obtained as the peak temperature of the calorific value. Unsaturated fatty acids
Amide is used when its amount exceeds 0.015 parts by weight.
In this case, the adhesive strength is reduced. Further, the layer (a) is unsaturated
No fatty acid amide is used, and ethylene-α-ole
The ethylene-α-olefin comprising only a fin copolymer.
The density of the resin is 0.925 to 0.945 g / cm
^ThreeIf it is, further from the point of the adhesive strength during dry lamination
preferable. For the anti-blocking agent, especially blended
Not necessary, but if blocking issues arise,
It may be added to the extent that the object of the invention is not impaired.

The ethylene-α-olefin copolymer used for the layer (b) constituting the multilayer film of the present invention comprises ethylene and an α-olefin having 3 to 12 carbon atoms, and has a density of 0.900 to 0.940 g / It is an ethylene-α-olefin copolymer having a cm ³ and a melt flow rate of 0.5 to 30 g / 10 minutes. The layer (b) is composed of 0.01 to 0.20 unsaturated fatty acid bisamide based on 100 parts by weight of the copolymer.
Parts by weight, 0.01 to 0.20 parts by weight of an unsaturated fatty acid amide having a melting point of 65 ° C to 90 ° C, and a weight average particle diameter of 8 parts by weight.
２０20 μ and a refractive index nD measured at 25 ° C. of 1.
Antiblocking agent 0.2 to 45 to 1.58
Contains 2.0 parts by weight.

When the layer (b) is laminated with another film substrate by a dry laminating method or the like, it becomes a heat seal layer, so that if the density is less than 0.900 g / cm ³ , n -The hexane-soluble content increases, causing problems such as hygiene or quality of the contents such as foods, stickiness of the film, and easy blocking. On the other hand, when the density exceeds 0.940 g / cm ³ , the flexibility of the obtained film is insufficient, and the low-temperature heat sealing property and the low-temperature hot tack property deteriorate.

The lubricant used in the layer (b) is a combination of unsaturated fatty acid amide and unsaturated fatty acid bisamide.
Unsaturated fatty acid amides are relatively quick to bleed to the film surface, and have a high effect of improving slip properties and anti-blocking properties immediately after processing. The unsaturated fatty acid amide used in the present invention has a melting point of 65 to 90 ° C. If the melting point is lower than 65 ° C, the anti-blocking property of the film becomes poor not only after lamination but also before lamination, while exceeding 90 ° C. And the effect of improving the slip property becomes insufficient. When the content of the unsaturated fatty acid amide is less than 0.01 part by weight, the effect of improving slipperiness and anti-blocking properties become insufficient, and when the content exceeds 0.2 part by weight, guide roll contamination during bag making or in the printing process. Causes poor secondary workability. Further, when the unsaturated fatty acid amide is bonded by a dry laminating method or the like, it is easily adsorbed by an adhesive, and when used alone, the slipperiness and the anti-blocking property after lamination become insufficient.

On the other hand, the unsaturated fatty acid bisamide has a relatively low bleeding effect on the film surface and therefore has little effect of improving the slipperiness and anti-blocking property immediately after processing, but is bonded to another film substrate by a dry laminating method or the like. Even when combined, there is little adsorption to the adhesive, slipperiness after dry ramet,
High improvement in anti-blocking properties. If the content of the unsaturated fatty acid bisamide is less than 0.01 part by weight, sufficient dryness-improving effect and anti-blocking property cannot be obtained after dry lamination, while if it exceeds 0.2 part by weight, the bag-forming or printing process In this case, secondary workability is inferior, such as causing guide roll contamination.

The anti-blocking agent has a weight average particle size of 8 to 20 μm, preferably 8 to 10 μm. When the weight average particle diameter is less than 8μ, the anti-blocking property required for the multilayer film of the present invention is insufficient, and when the weight average particle diameter exceeds 20μ, the anti-blocking property is excellent, It may cause a decrease in transparency and a deterioration in surface appearance. The weight average particle size of the anti-blocking agent refers to an average particle size based on the weight measured using a Coulter counter.

The anti-blocking agent has a refractive index nD measured at 25 ° C. of 1.45 to 1.58, preferably 1.48 to 1.52. Film cannot be obtained. Here, the refractive index of the anti-blocking agent is measured by a Larsen oil immersion method. The content of the anti-blocking agent is based on 100 parts by weight of the ethylene-α-olefin copolymer.
0.2 to 2.0 parts by weight is blended. When the amount is less than 0.2 parts by weight, the anti-blocking property required for the multilayer film of the present invention is insufficient. When the amount exceeds 2.0 parts by weight, the transparency of the multilayer film is excellent although the anti-blocking property is excellent. And causes the surface appearance to deteriorate.

Specific examples of the anti-blocking agent include a powder obtained by copolymerizing a raw material monomer and a cross-linking monomer to give various polymer powders and further copolymerizing with one or more other monomers. For example, organic anti-blocking agents such as cross-linked acrylic resin, cross-linked polymethyl methacrylate or cross-linked poly (methyl methacrylate-styrene) copolymer, cross-linked silicone, cross-linked polystyrene powder, synthetic aluminosilicate powder, diatomaceous earth, etc. Inorganic antiblocking agents. Among them, organic anti-blocking agents such as cross-linked acrylic resin, cross-linked polymethyl methacrylate, and powder of cross-linked poly (methyl methacrylate-styrene) copolymer are preferable.

In the multilayer film of the present invention, the layer (b) comprises ethylene and an α-olefin having 3 to 12 carbon atoms, a density of 0.900 to 0.940 g / cm ³ and a melt flow rate of 0.5 to 30 g. / 10 minutes to 100 parts by weight of an ethylene-α-olefin copolymer, 0.01 to 0.20 parts by weight of an unsaturated fatty acid bisamide, and a melting point of 65 ° C to 90 ° C.
C., 0.01 to 0.20 parts by weight of unsaturated fatty acid amide, a weight average particle diameter of 8 to 20 μm, and a refractive index nD measured at 25 ° C. in the range of 1.45 to 1.58. 0.2 to 2.0 parts by weight of a blocking agent, and an anti-blocking agent having a weight-average particle size of 3 to 8 μm and a weight-average particle size of 0.75 times or less the weight-average particle size of the anti-blocking agent By containing 0.1 to 1.0 part by weight, the anti-blocking property can be further improved. Here, when the weight average particle size exceeds 8 μm, transparency and appearance deteriorate, which is not preferable. On the other hand, when the weight average particle diameter is less than 3 μm, the anti-blocking property deteriorates, which is not preferable. When the content exceeds 1.0 part by weight, transparency and appearance are deteriorated.
If the amount is less than 1 part by weight, the anti-blocking property will be poor.

(A) constituting the multilayer film of the present invention,
In the ethylene-α-olefin copolymer used for the (b) layer, the density of the (a) layer and the (b) layer is (a) layer>
(B) a layer having a density difference of 0.005 g / c
m ³ or more. If the density difference is less than 0.005 g / cm ³ , it is difficult to simultaneously satisfy the low-temperature heat sealing property, the low-temperature hot tack property, and the mechanical strength of the film. Also,
A lubricant such as an unsaturated fatty acid amide or an unsaturated fatty acid bisamide easily bleeds into the layer (a), so that when laminating by a dry lamination method, the adhesive strength is reduced.

The purpose of the multilayer film of the present invention is as follows.
, One or more layers between the (a) layer and the (b) layer,
Of ethylene and carbon as an intermediate layer.
It is composed of α-olefin of the formulas 3 to 12, and has a density of 0.900.
~ 0.945g / cm^Three, Melt flow rate 0.5 ~
30 g / 10 min ethylene-α-olefin copolymer
Using the body, ethylene-α-olefin copolymer of each layer
(A) layer ≧ intermediate layer ≧ (b) layer, and
The density difference between the layer (a) and the layer (b) is 0.005 g / cm. ^ThreeLess than
The upper, at least three-layer film is a lubricant lubricant.
It is particularly preferable from the viewpoint of the card control.

The unsaturated fatty acid amide having a melting point of 65 ° C. to 90 ° C. used in the layers (a) and (b) of the present invention includes:
Examples include erucic acid amide and oleic acid amide. Examples of the unsaturated fatty acid bisamide include ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N'-diolel adipamide, N,
N'-dioleyl sebacic amide and the like. The melt flow rate is measured by a method specified in JIS-K7210, and the melt flow rate of the ethylene-α-olefin copolymer used for the (a) layer and the (b) layer is 0.5 to 30 g / 10 min. , Preferably in the range of 1 to 5 g / 10 minutes. The melt flow rate is 0.5 g / 10
If the melt flow rate is less than 30 g / 10 min, the extruded resin pressure will be large when extruding the finally obtained composition, and the extrudability will be greatly reduced. , And a film satisfactory for various packaging films cannot be obtained.

The material of the composition layer constituting the multilayer film of the present invention may be, for example, a melt blend of an ethylene-α-olefin copolymer and a lubricant or an anti-blocking agent, or a master batch of a lubricant or anti-blocking agent and an ethylene-α-olefin copolymer. α
-It can be obtained by, for example, dry blending an olefin copolymer. For the dry blending, various blenders such as a Henschel mixer and a tumbler mixer are used, and for the melt blending, for example, a single screw extruder,
Various mixers such as a screw extruder, a Banbury mixer, and a hot roll are used.

In order to produce the multilayer film of the present invention, techniques such as a co-extrusion method and an extrusion coating method (also referred to as an extrusion lamination method) are generally employed using an inflation film production apparatus or a T-die film production apparatus. can do. In the inflation method, a resin melt-kneaded by an extruder is extruded into a tube through a circular slit of a die, and the pressure of gas (usually air) blown into the tube is adjusted to a wide range. Films can be manufactured. The ratio of the width of the film to the diameter of the circular slit is determined by the blow-up ratio (BU
R). The thickness of the film can be adjusted by selecting the resin extrusion speed and BUR. The extruded tube is cooled by a gas (usually air) / liquid (usually water) from the outside. The T-die method is called a casting method, in which a resin melt-kneaded in an extruder is extruded through parallel slits of a die and is cooled by being brought into contact with a roll through which a coolant such as water is passed. And a film with good thickness accuracy can be manufactured. The thickness of the film can be adjusted by selecting the resin extrusion speed and the film take-up speed.

The substrate on which the multilayer film of the present invention is laminated can be selected from, for example, paper, paperboard, woven fabric, aluminum foil and the like, in addition to any polymer capable of forming a film.
Examples of the polymer capable of forming a film include polyamide resins such as nylon 6, nylon 66, nylon 11, and nylon 12, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polypropylene, poly-1-butene, and poly-4-methyl. -1-pentene, polyethylene, ethylene / vinyl acetate copolymer, ethylene / methacrylic acid ester copolymer, ethylene / acrylic acid copolymer, polyolefin resin such as ionomer, polyvinylidene chloride, polyvinyl chloride, polystyrene, polyvinyl Alcohol, ethylene / vinyl alcohol copolymer and the like can be mentioned. As these polymers, gas barrier properties, printability, transparency, rigidity,
It can be selected according to the purpose of forming a composite film in consideration of adhesiveness and the like. When the substrate is stretchable, especially when the film properties are improved by stretching such as polyamide resin, polyester resin, polypropylene, etc., the substrate may be uniaxially or biaxially stretched.

The multilayer film of the present invention has a thickness of 1 to 50.
It is preferably 0 μm, particularly preferably 10 to 100 μm.
The thickness of the base material layer is optional and can be selected according to the purpose.
A plurality of substrates can be combined with various configurations.

In the resin composition constituting the multilayer film of the present invention, 2,6-di-tert-butyl-p-cresol (BH
T), tetrakis [methylene-3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate] methane (IRGANOX1010) and n-octadecyl-
A phenolic stabilizer represented by 3- (4′-hydroxy-3,5′-di-t-butylphenyl) propionate (IRGANOX1076);
-Butylphenyl) pentaerythritol diphosphite, phosphite-based stabilizers represented by tris (2,4-di-butylphenyl) phosphite, etc., having 8 carbon atoms
To 22 fatty acid glycerin esters, sorbitan acid esters, polyethylene glycol esters, and the like.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. First, methods for measuring physical properties in the following Examples and Comparative Examples will be described. (1) Density (d) According to the method specified in JIS K6760. 100
After annealing for 1 hour in water at ℃, the density was measured. (2) Melt flow rate (MFR) In accordance with the method specified in JIS K6760. (3) Weight average particle size Coulter counter model TA-II manufactured by Nikkaki Co., Ltd.
And the aperture diameter was 20 μm or 200 μm, and the measurement was performed using an electrolytic solution ISOTON II. (4) Refractive index of anti-blocking agent Measured by the Larsen oil immersion method. Adjustment of Solvent α-Bromnaphthalene (n = 1.660 / 25 ° C.) and Kerosene (n = 1.443 / 25 ° C.) are mixed on a volume basis and the refractive index is increased from 1.4817 to 1.5907 in 0.005 steps. Was prepared. Measurement A few milligrams of the anti-blocking agent is placed on a slide glass, covered with a cover glass, the above solvent is impregnated through the gap, and observed with a light microscope using transmitted light. The refractive index at which the particle boundaries became invisible (hard to see) was taken as the refractive index of the anti-blocking agent.

(5) Haze (transparency) Measured according to ASTM D1003-61. (6) Appearance After conditioning the formed film at 23 ± 2 ° C. and 50 ± 5% RH for 24 hours or more, the anti-blocking agent contained in the formed film is observed, and the relative prominence of the conspicuousness is evaluated. Was determined. A: The anti-blocking agent is extremely inconspicuous. …: The anti-blocking agent looks small, but the number is small and not very noticeable. Δ: The anti-blocking agent looks small fish eye and is slightly conspicuous. X: The anti-blocking agent looks small fish eye and stands out. XX: The anti-blocking agent looks like a small fish eye, and a large number of the anti-blocking agent are scattered all over the film and stand out. (7) 1% secant modulus (1% -SM: Secant M)
Odurus) A test piece having a width of 2 cm was cut out in the processing direction (MD) of the film and attached to a tensile tester at a distance between chucks of 6 cm.
It was pulled at a speed of mm / min, and was obtained from the stress at the time of 1% elongation by a calculation formula of 100 × (stress) / (cross-sectional area).

(8) Anti-blocking Property (Shear Blocking) The dry laminate film produced by the below-described composite film production method was measured by the following method.
In the state where the formed film is laminated on the multilayer film surface, 20
After being cut into a size of 0 mm × 50 mm, left in a 50 ° C. oven for 30 minutes on a wire mesh, and then pressed in a press adjusted to 50 ° C. under a load of 180 kg / cm ² ,
After adhering for 50 minutes, the maximum stress required to peel off 50 cm ² of the adhered surface of the film in a shearing manner with a constant crosshead speed tensile tester at a pulling speed of 200 mm / min was measured. And The smaller the value, the better the anti-blocking property. (9) Coefficient of Friction (Slipperiness) The static friction coefficient (μS) and the dynamic friction coefficient (μk) of the dry laminated film produced by the composite film production method described below were measured in accordance with ASTM D-1894. (10) Adhesiveness A dry laminate film produced by a composite film production method described later was measured by the following method.
Elmendorf tear strength in the TD direction of the composite film was measured in accordance with ASTM D689, and was measured to be 10 kg /
cm or less, good adhesion (○), 10-20 kg /
cm, a little poor (△), and 20 kg / cm or more, (x).

The following samples were used in this example. Ethylene-α-olefin copolymer (1) Copolymer 1 Ethylene-1-hexene copolymer (d = 0.941 g
/ Cm ³ , MFR = 2.0 g / 10 min, Tm = 123
(C) (2) Copolymer 2 Ethylene-1-hexene copolymer (d = 0.931 g
/ Cm ³ , MFR = 1.9 g / 10 min, Tm = 123
° C) (3) Copolymer 3 ethylene-1-hexene copolymer (d = 0.921 g
/ Cm ³ , MFR = 1.9 g / 10 min, Tm = 121
(C) (4) Copolymer 4 ethylene-1-hexene copolymer (d = 0.912 g)
/ Cm ³ , MFR = 2.0 g / 10 min, Tm = 121
° C) (5) Copolymer 5 ethylene-1-butene copolymer (d = 0.930 g /
cm ³ , MFR = 2.0 g / 10 min, Tm = 121 ° C.) (6) Copolymer 6 Ethylene-1-butene copolymer (d = 0.921 g /
cm ³ , MFR = 2.0 g / 10 min, Tm = 123 ° C.) All of the above-mentioned ethylene α-olefin copolymers were produced by a high-pressure ionic polymerization method using a titanium-based catalyst.

Anti-blocking agent (1) ABA-1 cross-linked polymethyl methacrylate resin powder Weight average particle diameter = 6.5 μm, nD (25 ° C.) = 1.490 (2) ABA-2 cross-linked polymethyl methacrylate resin powder Weight average particle diameter = 10.0 μ, nD (25 ° C.) = 1.490 (3) ABA-3 crosslinked polymethyl methacrylate resin powder Weight average particle diameter = 15.0 μ, nD (25 ° C.) = 1.490 ( 4) ABA-4 Copolymer resin powder of methyl methacrylate and styrene Weight average particle diameter = 6.4μ, nD (25 ° C) = 1.520 (5) ABA-5 Copolymer resin powder of methyl methacrylate and styrene Weight Average particle diameter = 9.0μ, nD (25 ° C) = 1.520 (6) ABA-6 crosslinked styrene resin powder weight average particle diameter = 11.0μ,
nD (25 ° C.) = 1.590 (7) ABA-7 crosslinked styrene resin powder weight average particle diameter = 6.0 μ,
nD (25 ° C.) = 1.590 (8) ABA-8 diatomaceous earth weight average particle diameter = 5.5 μ (9) ABA-9 synthetic aluminosilicate weight average particle diameter = 4.9 μ,
nD (25 ° C.) = 1.490 (10) ABA-10 magnesium silicate weight average particle diameter = 10.0 μ, n
D (25 ° C.) = 1.500 (11) ABA-11 diatomaceous earth weight average particle diameter = 9.0 μ

Unsaturated fatty acid amide (1) SA-1 erucamide Melting point 82 ° C. Unsaturated fatty acid bisamide (1) SA-2 Ethylene bisoleic acid amide

Preparation of Masterbatch of Antiblocking Agent The blending of the antiblocking agent into the polyolefin resin was carried out by using a Banbury mixer, and the antiblocking agent was previously added to the ethylene-based resin used in each layer of the multilayer film of the present invention.
After melt-kneading the same resin as the α-olefin copolymer at a concentration of 10% by weight to form a master batch, ethylene-α
-It was subjected to dry blending with an olefin copolymer.

Production of Lubricant Masterbatch The compounding of the unsaturated fatty acid amide with the polyolefin resin is as follows:
Using a Banbury mixer, the unsaturated fatty acid amide was previously melt-kneaded at a concentration of 4% by weight with the same resin as the ethylene-α-olefin copolymer used for each layer of the multilayer film of the present invention to form a master batch. −
It was subjected to dry blending with an α-olefin copolymer.
In addition, the unsaturated fatty acid bisamide was mixed with the polyolefin resin by using a Banbury mixer, and the unsaturated fatty acid bisamide was previously added to the same resin as the ethylene-α-olefin copolymer used in each layer of the multilayer film in an amount of 2% by weight. % Was melt-kneaded to form a master batch, which was then subjected to dry blending with an ethylene-α-olefin copolymer.

Preparation of Ethylene-α-Olefin Copolymer Composition and Production of Multilayer Film When the multilayer film has two layers, specific ethylene-α-olefin constituting each of the (a) layer and the (b) layer The mixture obtained by dry-blending the copolymer, the anti-blocking agent, and the lubricant at a predetermined ratio is melt-kneaded using two extruders, (a) the layer with a 90φ extruder, and (b) the layer with a 65φ extruder, Feed block type T die (die width 1250m
m, lip opening 1.5mm) and extruded, 23
Die set temperature of 0 ° C, chill roll temperature of 40 ° C, 70m
A 30 µm multilayer film was obtained at a processing speed of / min. Also,
When the multilayer film has three layers, a mixture obtained by dry blending a specific ethylene-α-copolymer, an anti-blocking agent and a lubricant in a predetermined ratio, which constitute each of the layer (a), the layer (b) and the intermediate layer, Using three extruders, the (a) layer was a 65φ extruder, the (b) layer was a 65φ extruder, and the intermediate layer was 9
The mixture is melt-kneaded with a 0φ extruder, introduced into a feed block type T die (die width 1250 mm, lip opening 1.5 mm) and extruded, and a die set temperature of 230 ° C., a chill roll temperature of 40 ° C., and 70 m / min. A 60 μm multilayer film was obtained at a processing speed.

Production of Composite Film The above-mentioned multilayer film was prepared using a desktop test coater manufactured by Yasui Seiki.
2 g / m of film ^TwoEther-based adhesive
(Main agent Toyo Morton AD308A, curing agent Toyo Mort
15μ thick stretched nylon base coated with CAT8B)
Material film (Unitika emblem), 40 ℃,
3kg / cm^TwoAnd then heated at 40 ° C for 2 days
Dry lamination composite film by aging
I got

Examples 1 to 8 and Comparative Examples 1 to 5 Films were formed by the above-mentioned method using the raw materials and the resins shown in Tables 1 to 10. The transparency, appearance, and rigidity (1% SM) of the obtained multilayer film were measured. Furthermore, after laminating this film to a stretched nylon substrate by a dry lamination method according to the method described above, anti-blocking properties,
Slipperiness and adhesiveness were evaluated. The evaluation results are shown in Tables 2, 4, 6,
8 and 10 respectively.

[0043]

Table 1 Example 1 Example 2 Example 3 ───────────────────────────────── (a) layer ethylene-α-olefin copolymer copolymer 2 copolymer Polymer 2 Copolymer 3 Thickness μ 20 20 20 No anti-blocking agent None ABA-9 Amount used (parts by weight) ─── ─── 0.20 Unsaturated fatty acid amide None NA-1 Used amount by weight ─── ─── 0.015 ───────────────────────────────────

[0044]

[Table 2] Example 1 Example 2 Example 3 ───────────────────────────────── (b) layer Ethylene-α-olefin copolymer Copolymer 3 copolymer Polymer 3 Copolymer 4 Thickness μ 10 10 10 Anti-blocking agent ABA-2 ABA-2 ABA-2 Used amount by weight 1.5 1.0 1.2 Anti-blocking agent None ABA-1 ABA-9 Used amount Parts by weight ─── 0.5 0.6 unsaturated fatty acid bisamide SA-2 SA-2 SA-2 used amount by weight 0.15 0.15 0.12 unsaturated fatty acid amide SA-1 SA-1 SA-1 Amount used parts by weight 0.09 0.09 0.04 ───────────────────────────────── ─ Haze (%) 6.8 6.4 5.8 Appearance ○ ○ ○ 1% -SM 1350 1350 850 Shear blocking ^{(kg / 50cm 2) 2.0 1.7} 2.5 Friction coefficient .mu.s 0.11 0. 11 0.13 μk 0.10 0.10 0.13 Adhesion ○ ○ ○ ─────────────────────────────── ────

[0045]

[Table 3] Example 4 Example 5 Example 6 ───────────────────────────────── (a) layer ethylene-α-olefin copolymer copolymer 2 copolymer Polymer 1 Copolymer 1 Thickness μ 8 8 10 Intermediate layer Ethylene-α-olefin copolymer Copolymer 3 Copolymer 3 Copolymer 6 Thickness μ 44 44 40 Unsaturated fatty acid bisamide SA-2 SA-2 SA -2 used amount by weight 0.02 0.02 0.04 unsaturated fatty acid amide SA-1 SA-1 SA-1 used amount by weight 0.03 0.03 0.04 ───────── ──────────────────────────

[0046]

[Table 4] Example 4 Example 5 Example 6 ───────────────────────────────── (b) layer ethylene-α-olefin copolymer copolymer 4 copolymer Polymer 3 Copolymer 3 Thickness μ 8 8 10 Use of antiblocking agent ABA-5 ABA-2 ABA-3 Weight part 1.2 1.0 1.0 Use of antiblocking agent ABA-4 ABA-8 ABA-9 Amount Part by weight 0.6 0.5 0.5 Unsaturated fatty acid bisamide SA-2 SA-2 SA-2 Amount used Part by weight 0.12 0.10 0.12 Unsaturated fatty acid amide SA-1 SA-1 SA- 1 Amount used parts by weight 0.06 0.03 0.12 ──────────────────────────────── ── Haze (%) 6.5 7.7 8.2 Appearance ◎ ○ ○ 1% -SM 1660 1800 1980 Shear blocking ^{(kg / 50cm 2) 2.5 2.2} 1.9 Friction coefficient .mu.s 0.17 0 .18 0.12 μk 0.16 0.18 0.11 Adhesion ○ ○ ○ ────────────────────────────── ─────

[0047]

Table 5 Example 7 Example 8 ────────────────── (a) layer ethylene-α-olefin copolymer copolymer 1 copolymer 5 thickness μ 10 8 intermediate layer ethylene-α-olefin copolymer Polymer Copolymer 2 Copolymer 6 Thickness μ 40 44 Unsaturated fatty acid bisamide SA-2 SA-2 Used part by weight 0.02 0.02 Unsaturated fatty acid amide SA-1 SA-1 Used part by weight 0. 03 0.03 ─────────────────────────────

[0048]

Table 6 Example 7 Example 8 ────────────────── (b) layer Ethylene-α-olefin copolymer Copolymer 2 Copolymer 6 Thickness μ 10 8 Anti-blocking agent ABA-2 ABA- 10 Amount used parts by weight 0.8 1.4 Antiblocking agent ABA-9 ABA-9 Amount used parts by weight 0.4 0.7 Unsaturated fatty acid bisamide SA-2 SA-2 Used amount parts by weight 0.08 0.10 Unsaturated fatty acid amide SA-1 SA-1 Usage part by weight 0.03 0.03 ───────────────────────────── Haze (%) 8.7 8.3 Appearance ○ ○ 1%-SM 2710 1903 Shear blocking (kg / 50 cm ² ) 3.1 3.3 Coefficient of friction μs 0.19 0.18 μk 0.20 0.18 Adhesion ○ ○ ─────────────────────────────

[0049]

[Table 7] Comparative Example 1 Comparative Example 2 Comparative Example 3 ───────────────────────────────── (a) layer ethylene-α-olefin copolymer copolymer 3 Polymer 1 Copolymer 1 Thickness μ20 10 8 Antiblocking agent ABA-9 None used Amount 0.2 parts by weight Unsaturated fatty acid amide SA-1 None Used Amount 0.02 ─── 中間 Intermediate layer Ethylene-α-olefin copolymer None Copolymer 3 Copolymer 3 Thickness μ ４０ 40 44 Unsaturated fatty acid bisamide None SA-2 SA-2 Usage Parts by weight ─── 0.02 0.02 Unsaturated fatty acid amide None SA-1 SA-1 Amount used Parts by weight ─── 0.03 0.03 ── ────────────────────────────────

[0050]

Table 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 ───────────────────────────────── (b) layer Ethylene-α-olefin copolymer Copolymer 3 copolymer Polymer 3 Copolymer 4 Thickness μ 10 10 8 Antiblocking agent ABA-2 ABA-1 ABA-6 Used amount by weight 1.0 1.5 1.0 Antiblocking agent ABA-1 None ABA-7 Used amount Parts by weight 0.5０．５0.5 unsaturated fatty acid bisamide SA-2 SA-2 SA-2 amount used parts by weight 0.10 0.10 0.10 unsaturated fatty acid amide SA-1 SA-1 SA-1 Amount used parts by weight 0.03 0.03 0.03 ────────────────────────────────── Haze (%) 6.5 8.4 9.7 Appearance ○ ◎ ×× 1% -SM 960 1800 1800 Shear blocking ^{(kg / 50cm 2) 3.1 4.9} 2.1 Friction coefficient .mu.s 0.17 0. 18 0.18 μk 0.16 0.18 0.18 Adhesion × ○ ○ ─────────────────────────────── ────

[0051]

[Table 9] Comparative Example 4 Comparative Example 5 Comparative Example 6 ───────────────────────────────── (a) layer ethylene-α-olefin copolymer copolymer 1 copolymer Polymer 3 Copolymer 1 Thickness μ 10 10 10 No antiblocking agent None ABA-9 None Amount used (parts by weight) {0.2} Unsaturated fatty acid amide None SA-1 None Amount used (parts by weight) {0.02} Intermediate layer Ethylene-α-olefin copolymer Copolymer 3 Copolymer 2 Copolymer 2 Thickness μ 40 40 40 Unsaturated fatty acid bisamide SA-2 SA-2 Use of SA-2 Amount Weight part 0.02 0.02 0.02 Unsaturated fatty acid amide SA-1 SA-1 SA-1 Amount used Weight part 0.03 0.0 0.03 ───────────────────────────────────

[0052]

Table 10 Comparative Example 4 Comparative Example 5 Comparative Example 6 ───────────────────────────────── (b) layer Ethylene-α-olefin copolymer Copolymer 3 copolymer Polymer 3 Copolymer 3 Thickness μ 10 10 10 Use of antiblocking agent ABA-2 ABA-2 ABA-2 Weight part 0.15 1.2 1.0 Antiblocking agent ABA-1 ABA-9 Use of ABA-11 Amount Part by weight 0.5 0.6 0.5 Unsaturated fatty acid bisamide SA-2 SA-2 SA-2 Amount used Part by weight 0.10 0.10 0.10 Unsaturated fatty acid amide SA-1 SA-1 SA- 1 Amount used parts by weight 0.03 0.03 0.03 ───────────────────────────── ────── Haze (%) 5.2 9.1 9.8 Appearance ○ ○ × 1%-SM 1800 2700 1980 Shear blocking (kg / 50 cm ² ) 5.6 3.5 2.1 Coefficient of friction μs 0.21 0.12 0.14 μk 0.19 0.11 0.14 Adhesion ○ × ○ ────────────────────────── ─────────

[0053]

As described above in detail, according to the present invention, it is possible to provide a multilayer film which is excellent in optical properties such as transparency and appearance, and in particular, has remarkably improved antiblocking property. In particular, the multilayer film of the present invention is effective as a packaging film having a high opening property without using starch, which is conventionally used at the time of dry lamination and is mainly made of corn, due to a remarkable improvement in antiblocking properties. . Further, the multilayer film of the present invention,
Foods that can be used alone or in a state of being laminated with other base materials and packaged with water such as konjac, pickles, etc.
It is suitable for the packaging of various products such as liquid foods such as milk, sake and soy sauce, dried foods such as confectionery, processed meats such as ham and sausage, as well as electric parts, chemicals and the like.

Claims (10)

(57) [Claims] (1) The layer (a) is composed of ethylene and an α-olefin having 3 to 12 carbon atoms, and has a density of 0.905 to 0.945 g / cm ³ ,
With respect to 100 parts by weight of an ethylene-α-olefin copolymer having a melt flow rate of 0.5 to 30 g / 10 minutes, an unsaturated fatty acid amide having a melting point of 65 ° C to 90 ° C is added to 0.0 parts by weight.
15 not or no content parts hereinafter to containing Yes, (b) layer consists of ethylene and 3 to 12 carbon atoms α- olefin, the density 0.900~0.940g / cm ^3,
With respect to 100 parts by weight of an ethylene-α-olefin copolymer having a melt flow rate of 0.5 to 30 g / 10 minutes, 0.01 to 0.20 parts by weight of an unsaturated fatty acid bisamide and a melting point of 65 ° C to 90 ° C. Unsaturated fatty acid amide 0.01 ~
0.20 parts by weight and a weight average particle diameter of 8 to 20 μ and a refractive index nD measured at 25 ° C. of 1.45 to 1.5
8, containing 0.2 to 2.0 parts by weight of the antiblocking agent, wherein the density of the (a) layer and the (b) layer is (a)> (b), and the density difference Is not less than 0.005 g / cm ³ . 2. The multilayer film according to claim 1, wherein the anti-blocking agent of the layer (b) is an organic anti-blocking agent. 3. The multilayer film according to claim 1, wherein the anti-blocking agent of the layer (b) is a crosslinked acrylic resin powder. 4. The multilayer film according to claim 1, wherein the anti-blocking agent of the layer (b) is a crosslinked polymethyl methacrylate resin powder. 5. The multilayer film according to claim 1, wherein the anti-blocking agent of the layer (b) is a crosslinked resin powder comprising a copolymer of methyl methacrylate and styrene. 6. The multilayer film according to claim 1, wherein the anti-blocking agent in the layer (b) has a weight average particle size of 8 to 10 μm. 7. The multilayer film according to claim 1, wherein the refractive index nD of the anti-blocking agent in the layer (b) measured at 25 ° C. is in the range of 1.48 to 1.52. 8. The layer (b) comprises ethylene and an α-olefin having 3 to 12 carbon atoms, and has a density of 0.900 to 0.940.
g / cm ³ , melt flow rate 0.5 to ³⁰ g / 10
Of the unsaturated fatty acid bisamide to 100 parts by weight of the ethylene-α-olefin copolymer
Parts by weight, 0.01 to 0.20 parts by weight of an unsaturated fatty acid amide having a melting point of 65 ° C to 90 ° C, and a weight average particle size of 8 to 2
0 μ and a refractive index nD measured at 25 ° C. of 1.45.
Anti-blocking agent 0.2 to 1.58
2.0 parts by weight, and a weight average particle size of 3 to 8 μm,
And the weight average particle diameter of the anti-blocking agent is 0.7
The multilayer film according to claim 1, comprising 0.1 to 1.0 part by weight of an anti-blocking agent having a weight average particle diameter of 5 times or less. 9. The method according to claim 1, wherein the layer (a) comprises only an ethylene-α-olefin copolymer, and the density of the ethylene-α-olefin copolymer is 0.925 to 0.945 g / cm ^3. The multilayer film according to the above. 10. The multilayer film according to claim 1, wherein between the (a) layer and the (b) layer, ethylene and a carbon number of 3 to 3 are used as an intermediate layer.
12 α-olefins having a density of 0.900 to 0.1.
945 g / cm ³ , melt flow rate 0.5 to 30 g
(C) layer containing an ethylene-α-olefin copolymer which is / 10 min, and the density of the ethylene-α-olefin copolymer in each layer is (a) layer ≧ (c) layer ≧ (b) And the density difference between the (a) layer and the (b) layer is 0.005 g /
multilayer film comprising at least three layers, wherein at cm ³ or more.