JPH0853554A - Food packaging film - Google Patents

Abstract

(57) [Summary] (Modified) [Composition] Consisting of ethylene and C _3-12 α-olefin, and having a melt flow rate of 0.5 to 30 g / 10.
And the GPC method M _N is 35,000 to 150,000.
0, M _W / M _N is 1.8 to 3.0, and the maximum melting peak temperature by differential scanning calorimeter is 60 to 110.
Consists of an ethylene / α-olefin copolymer and a mixture thereof, which are observed in the range of ℃, and have a density of 0.895.
A film for food packaging, which has a content of ˜0.910 g / cm ³ and an n-hexane-soluble content of 6% by weight or less. [Effect] The temperature at which heat-sealing property develops is low, the extractability for hydrocarbon solvents is low, and the balance of physical properties such as transparency, gloss, impact strength and tear strength is excellent, and all important properties as a film for food packaging. In the form of a monolayer film or a composite film, it can be used for packaging various foods such as konjac, pickles, milk, liquor, soy sauce dried foods, ham and sausages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a food packaging film which is excellent in heat sealability and has suitable properties such as food hygiene.

[0002]

2. Description of the Related Art Most of packaging materials are ethylene resins such as polyethylene, ethylene / α-olefin copolymers, ethylene / vinyl acetate copolymers, ionomers, etc. from the viewpoint of excellent heat-sealing properties and food hygiene. Is used as a heat seal layer. At present, in which packaging forms have been diversified, in order to sufficiently satisfy the performance required for materials, many of them take a form in which an ethylene polymer resin is laminated on another suitable film.

For example, a film such as stretched polyamide or polyethylene terephthalate is often used as a base material for food packaging, but a single substance is excellent in many aspects such as impact strength, rigidity, gas barrier property and food hygiene. However, it has a drawback that the heat sealability is poor. On the other hand, the polyolefin resin film alone has good heat-sealing properties, but is inferior to the above-mentioned base film in terms of impact strength and rigidity. Generally, a method of stacking is used to complement the defects of both.

The above ethylene-based copolymer used for food packaging materials is required to have properties such as low-temperature heat sealability and food hygiene in addition to mechanical strength such as impact strength, tensile strength and tear strength. ing.

Many materials have been proposed so far as ethylene-based resins used in the heat-sealing layer of food packaging materials. However, in the conventional technology,
In the case of a material having excellent heat-sealing property, some of the components in the ethylene-based resin migrate into the food depending on the food to be packaged, which causes a food hygiene problem. In particular, it cannot be used when the food is oily. Usually, the amount of extraction with respect to n-hexane is used as an index showing the degree of migration of the components in the ethylene resin into food.

[0006]

Generally, in order to improve the low-temperature heat-sealing property of the ethylene-based copolymer, a means of lowering the density of the ethylene-based resin is taken. As a result, the amount of transferred components is increased. On the contrary, if the density is increased in order to reduce the amount of transferred components, the low temperature heat sealability is deteriorated.

The present invention is intended to provide a composition suitable for food packaging materials and a film thereof,
Specifically, in addition to mechanical strength such as impact strength, tensile strength, tear strength, etc., the purpose is to obtain a food packaging film having performance required as a food packaging material such as low temperature heat sealability and food hygiene. I am trying.

[0008]

The inventors of the present invention have made extensive studies to solve these problems, and as a result, the specific ethylene / α-olefin copolymer or a mixture thereof solves these problems. It has been found that, in addition to excellent mechanical properties, a resin composition having a low extractability with a hydrocarbon solvent and a good low-temperature heat-sealing property and a film thereof can be obtained.

That is, the present invention comprises ethylene and an α-olefin having 3 to 12 carbon atoms, has a melt flow rate of 0.5 to 30 g / 10 minutes, and has a number average molecular weight of 35,000 as measured by the GPC method. ~ 150,000
And the molecular weight distribution represented by the ratio of weight average molecular weight / number average molecular weight is 1.8 to 3.0, and the maximum melting peak temperature by a differential scanning calorimeter is observed within the range of 60 to 110 ° C. Ethylene / α-olefin copolymer and a mixture thereof having a density of 0.895 to 0.9.
The present invention relates to a film for food packaging, which has a content of 10 g / cm ³ and an n-hexane-soluble content of 6% by weight or less.

In the ethylene / α-olefin copolymer and the mixture thereof of the present invention, the α-olefin to be copolymerized with ethylene has 3 to 12 carbon atoms. Specifically, propylene, butene-1, pentene-1, 4-
Methyl pentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, dodecene-1, etc. and mixtures thereof can be mentioned. Of these, particularly preferred are propylene, butene-1,
4-methylpentene-1, hexene-1, 4-methylhexene-1, and octene-1. Butene-1 and hexene-1 are more preferred. The α-olefin content in the ethylene / α-olefin copolymer is preferably 5 to 40 mol%.

In producing the ethylene / α-olefin used in the ethylene / α-olefin copolymer and the mixture thereof of the present invention, generally, an ionic polymerization method is used to produce the ethylene / α-olefin.
In the presence of a Ziegler-based catalyst or a metallocene-based catalyst, usually 30 to 300 ° C., normal pressure to 3000 kg / c.
m ^2, the presence or absence of a solvent of a solvent, gas - solid, liquid - are produced under solid or homogeneous liquid phase.

The Ziegler catalyst is a catalyst system composed of a vanadium compound and an organoaluminum compound, and the metallocene catalyst is a compound having a specific structure containing a transition metal, an oxygen-containing organoaluminum compound or a specific boron compound and an organoaluminum. Examples thereof include a catalyst system including a compound. These catalysts remain the same,
Alternatively, it can be used by being supported on silica or a polymer carrier.

The metallocene catalyst is represented by the general formula R ¹ _k
R ² _l R ³ _m R ⁴ _n M (where M is zirconium, titanium, hafnium or vanadium, R ¹ is a group having a cycloalkadienyl skeleton, and R ² , R ³ and R ⁴ are cycloalkaline). A group having a dienyl skeleton, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a halogen atom or hydrogen, k and l are integers of 1 or more, and k +
l + m + n = 4. ), 1. 1. a transition metal compound containing a ligand having a cycloalkadienyl skeleton, and A catalyst system composed of a compound mainly containing an organoaluminum oxide compound can be mentioned.

For example, the following compounds are used as the transition metal compound containing a ligand having a cycloalkadienyl skeleton. Examples of the transition metal compound containing a ligand having a cycloalkadienyl skeleton include bis (cyclopentadienyl) diethyltitanium, bis (cyclopentadienyl) dimethyltitanium, bis (pentamethylcyclopentadienyl) titanium, and bis (Cyclopentadienyl) dichlorotitanium, bis (cyclopentadienyl) titanium monochloride monohydride, bis (indenyl) titanium monochloride monohydride, bis (indenyl) titanium dichloride, ethylenebis (indenyl) dimethyltitanium, ethylenebis ( Indenyl) methyltitanium chloride, ethylenebis (indenyl) titanium dichloride, ethylenebis (4,5,6,7-tetrahydro-1-indenyl)
Titanium dichloride, ethylene bis (4,5,6,7
-Tetrahydro-1-indenyl) dimethyltitanium, ethylenebis (4-methyl-1-indenyl) titanium dichloride, ethylenebis (2,3-dimethyl-
1-indenyl) titanium dichloride, bis (cyclopentadienyl) diethyltitanium, bis (cyclopentadienyl) dimethylzirconium, bis (pentamethylcyclopentadienyl) zirconium, bis (cyclopentadienyl) dichlorozirconium, bis ( Cyclopentadienyl) monochloride monohydride, bis (indenyl) zirconium monochloride monohydride, bis (indenyl) zirconium dichloride,
Ethylenebis (indenyl) dimethylzirconium, ethylenebis (indenyl) methylzirconium chloride, ethylenebis (indenyl) zirconium dichloride, ethylenebis (4,5,6,7-tetrahydro-1)
-Indenyl) zirconium dichloride, ethylenebis (4,5,6,7-tetrahydro-1-indenyl) dimethylzirconium, ethylenebis (4-methyl-1-)
Examples thereof include indenyl) zirconium dichloride and ethylenebis (2,3-dimethyl-1-indenyl) zirconium dichloride. Preferably, biscyclopentadienyldimethyltitanium, bispentadienyltitanium dichloride, biscyclopentadienyldimethylzirconium and bispentadienylzirconium dichloride are used.

Examples of the oxygen-containing organoaluminum compound include tetramethyldialuminoxane, tetraethyldiaminoxane, tetrabutyldialuminoxane, tetrahexyldialuminoxane, methylaluminoxane, ethylaluminoxane, butylaluminoxane, and hexylaluminoxane. Of these, methylaluminoxane is preferably used.

Compound of vanadium compound and organoaluminum
Examples of the catalyst system composed of a substance include a vanadium compound and
Then, the general formula VO (OR)_nX_3-n(However, R is carbonized
A hydrogen group, X represents halogen, and a number satisfying 0 ≦ n ≦ 3. )
, VOCl₃, VO (OCH₃) Cl₂, VO
(OCH₃)₂ Cl, VO (OCH₃)₃, VO (OC₂ H
_Five) Cl₂, VO (OC₂ H_Five)₂ Cl, VO (OC₂ H_Five)
₃ , VO (OC₃ H₇) Cl₂, VO (OC₃ H₇)₂ C
l, VO (OC₃ H₇)₃ , VO (OisoC₃ H₇) Cl
₂, VO (OisoC₃ H₇)₂ Cl, VO (OisoC
₃ H₇)₃ Alternatively, a mixture of these can be exemplified.
It Of these compounds, compounds represented by 0 ≦ n ≦ 1
The thing is used especially preferable.

The organoaluminum compound has the general formula
R ’_mAlX_3-m(However, R'is a hydrocarbon group, X is a halo.
Gen, 1 ≦ m ≦ 3. ), (C₂ 
H_Five) ₂ AlCl, (C_Four H₉)₂AlCl, (C₆ H₁₃)₂
AlCl, (C₂ H_Five)_1.5 AlCl_1.5, (C_Four H₉)
_1.5 AlCl_1.5, (C₆ H₁₃)_1.5AlCl_1.5, C₂
H_Five AlCl₂, C_Four H₉ AlCl₂, C₆ H₁₃AlC
l₂Etc. can be illustrated. More preferable effects in the present invention
In order to exert the above, 1 ≦ m ≦ 2 is satisfied,
Especially (C₂ H_Five)_1.5 AlCl_1.5 Is preferably used
It

The ethylene / α-olefin copolymer and the mixture thereof used in the present invention have a density of 0.
In the range of 895~0.910g / cm ^3, the density of 0.895 g / cm ³ or less, or cause problems in food hygiene n- hexane solubles is increased, resulting stickiness in the film, a blocking Easier to do. Conversely, 0.910
When it is at least g / cm ^3, the flexibility of the film of the obtained composition is insufficient, the low-temperature heat-sealing property is deteriorated, and the feel as a film for food packaging is deteriorated.

The mixture of the present invention is composed of ethylene and an α-olefin having 3 to 12 carbon atoms, has a melt flow rate of 0.5 to 30 g / 10 minutes and a number average molecular weight of 35,000 as measured by the GPC method. Is 150,000, the molecular weight distribution represented by the ratio of weight average molecular weight / number average molecular weight is 1.8 to 3.0, and the maximum melting peak temperature by a differential scanning calorimeter is observed within the range of 60 to 110 ° C. Ethylene / α-olefin copolymer having a density of 0.
860 to 0.900 g / cm ³ and 0.900 g / cm ³
a mixture of more than cm ³ , preferably with a density of 0.880-0.900 g / cm ³ and 0.900 g / c.
Those exceeding m ³ are used.

The MFR is measured by the method specified in Condition 4 of Table 1 of JIS-K7210. The MFR of the ethylene / α-olefin copolymer and the mixture thereof used in the present invention is 0.5 to 30 g / 10 min, and the number average molecular weight measured by the GPC method is 35,000 to 150,
000. When the MFR is less than 0.5 g / 10 min or the number average molecular weight is more than 150,000, an extruder is used when the finally obtained composition is extruded in order to obtain the food packaging film of the present invention. The tree finger pressure is increased and the extrudability is reduced. Conversely, MFR is 30g / 1
If it is 0 minutes or more or the average molecular weight is less than 35,000, take-up surging is likely to occur during extrusion processing, which is not preferable in terms of film forming property, and a satisfactory film for food packaging cannot be obtained. .

Further, the ethylene / α-olefin copolymer of the present invention has a molecular weight distribution, expressed by the ratio of weight average molecular weight / number average molecular weight, measured by GPC method of 1.8 to
It is 3.0. If this value is less than 1.8, the molding load will be difficult due to an increase in the motor load during extrusion molding, and if it exceeds 3.0, the molding processability will be improved, but satisfactory heat sealing properties will not be obtained.

The maximum melting peak temperature of the ethylene-α-olefin copolymer is obtained by measuring the heat of fusion based on JIS K7122 using a Perkin-Elmer 7 type DSC apparatus. The measurement method is K712
It complies with paragraph 3- (2) of 1. Ethylene / α-of the present invention
In the case of an olefin copolymer and a mixture thereof, it is the highest peak temperature among the endothermic peaks present in one or more of the endothermic curves obtained by the above method, and is 60 to 110.
It is important to be present at ° C. Preferably 70 to 1
It is in the range of 05 ° C, more preferably 80 to 100 ° C. There may be a plurality of endothermic peaks, but one having only one is particularly preferably used.

Further, it is important that the n-hexane soluble content of the ethylene / α-olefin copolymer and the mixture thereof is 6% by weight or less. Considering a more preferable balance of heat sealing properties, other mechanical properties and safety and hygiene, it is preferable that the n-hexane-soluble content is 5% by weight or less.

Insoluble matter in n-hexane is the FDA standard No. 17
It is measured by the maximum elution amount measurement method with n-hexane at 50 ° C. described in Chapter 7, Section 1520. Specifically, a predetermined amount of a sample sample is kept in n-hexane at 50 ° C. for 2 hours, insoluble components are filtered, and the solvent residue is concentrated to dryness. Was calculated.

When the n-hexane-soluble content of this composition is 6% by weight or more, some of the components in the film are transferred to the packaged food, which may cause food hygiene problems or the film surface. Stickiness may occur, which may cause blocking or impair heat seal properties.

To obtain the food packaging film of the present invention, an ethylene / α-olefin copolymer is formed alone,
When the mixture is used, each is dry-blended or melt-blended. Various blenders such as a Henschel mixer and a tumbler mixer are used for the dry blend, and various mixers such as a single screw extruder, a twin screw extruder, a Banbury mixer, and a heat roll are used for the melt blend.

In order to produce a food packaging film using the ethylene / α-olefin copolymer and the mixture thereof of the present invention, it can be generally produced by a known technique such as an inflation method or a T-die method.

The inflation method is also called a blow molding method, in which the resin melt-kneaded by an extruder is extruded into a tube shape through a circular slit of a die, and the pressure of gas (usually air) blown into the tube. A film having a wide range of width can be manufactured by adjusting The ratio of the width of the film to the diameter of the circular slit is called the blow up ratio (BUR). The thickness of the film can be adjusted by selecting the resin extrusion rate and the BUR. The extruded tube is cooled from its outside by gas (usually air) and / or liquid (usually water).

The T-die method is called a cast method, in which the resin melt-kneaded by an extruder is extruded through parallel slits of a die and is cooled by being brought into contact with a roll in which a coolant such as water is passed, Generally, a film having good transparency and good thickness accuracy can be produced. The thickness of the film can be adjusted by selecting the resin extrusion rate and the film take-off rate.

The thickness of the monolayer film comprising the ethylene / α-olefin copolymer composition of the present invention is 2 to 5
It is preferably 00 μm, particularly 5 to 100 μm. If the thickness is less than this range, it is difficult to process and it becomes difficult to exhibit the heat-sealing property.

The food packaging film of the present invention is in the form of a composite film with another substrate, in order to sufficiently exhibit its excellent low-temperature heat-sealing property and low cold n-hexane extractability, It is preferable that the ethylene / α-olefin copolymer composition film of the present invention is present as a surface layer on at least one side.

The substrate may be selected from any polymer capable of forming a film, cellophane, paper, paperboard, woven fabric, aluminum foil and the like. 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 ester copolymer, ethylene / methacrylic acid copolymer, ethylene /
Acrylic acid copolymer, polyolefin resin such as ionomer, polyvinylidene chloride, polyvinyl chloride, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, etc., each gas barrier property, printability, transparency, rigidity, It can be selected according to the purpose of forming the composite film in consideration of adhesiveness and the like. The substrate may be uniaxially or biaxially stretched when the substrate is stretchable, particularly when the properties of the film are improved by stretching such as polyamide resin, polyester resin, polypropylene and the like. When in the form of a composite film, the layer thickness of the food packaging film according to the invention is preferably 1 to 500 μm, in particular 5 to 100 μm. The thickness of the base material layer is arbitrary and can be selected according to the purpose. It is already widely practiced to combine a plurality of base materials with various configurations, and the present invention can also be adopted.

In the present invention, the composite film having two or more layers can be formed by a lamination method such as a dry lamination method, a wet lamination method, a sandwich lamination method or a hot melt lamination method, a coextrusion method, an extrusion coating method, or an extrusion lamination method. Called) and combinations thereof.

In the lamination method, the film of the present invention obtained by the method described in the description of the monolayer film and the above-mentioned substrate are solvent-based adhesive, water-based adhesive,
It is pasted together with a hot melt adhesive, a molten polymer or the like.

In the coextrusion method, the melted / extruded ethylene / α-olefin copolymer composition of the present invention and the other melted / extruded polymer are brought into contact with each other inside and / or outside the die.

In the extrusion coating method, the surface of at least one side of another substrate is coated with the melted / extruded ethylene / α-olefin copolymer composition of the present invention. These details are described in "Handbook of Laminating Process" published by the Processing Technology Research Group.

In the food packaging film of the present invention, in order to further improve the physical properties, 2,6-di-
t-butyl-p-cresol (BHT), tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane (IRGAN
OX 1010) and n-octadecyl-3- (4′-hydroxy-3,5′-di-t-butylphenyl) propionate (IRGANOX 1076), a phenolic stabilizer represented by bis (2,4-di-). t-Butylphenyl) pentaerythritol diphosphite and phosphite stabilizers represented by tris (2,4-di-t-butylphenyl) phosphite, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid Amide, erucic acid amide, ethylenebispalmitic acid amide, ethylenebisstearic acid amide, hexamethylenebisstearic acid amide, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, N,
Lubricants typified by higher fatty acid amides such as N'-dioleyl sebacic acid amide, antistatic agents such as glycerin ester of carboxylic acid having 8 to 22 carbon atoms, sorbitan acid ester, polyethylene glycol ester, silica, calcium carbonate, talc An anti-blocking agent represented by, for example, is added.

[0038]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

First, methods for measuring physical property values in the following examples and comparative examples will be described. (1) Density (d) According to the method specified in JIS K6760. 100
The density was measured after annealing in water at ℃ for 1 hour. (2) Melt flow rate (MFR) According to the method specified in JIS K6760.

(3) Maximum melting peak temperature (Tm) For the measurement, a differential scanning calorimeter (DSC) DSC-7 manufactured by Perkin Elmer was used. About 10 mg of a test piece cut out from a sheet with a thickness of about 0.5 mm prepared by hot pressing was put in a sample pan for DSC measurement, and 150 ° C. in DSC.
Was pre-melted for 5 minutes, cooled to 40 ° C. at 1 ° C./minute, held for 5 minutes, and then heated to 150 ° C. at a rate of 10 ° C./minute to obtain a thermogram. When there were multiple melting peaks, the highest value was taken as the highest melting peak temperature.

(4) Number average molecular weight (Mn) and molecular weight distribution (Q) GPC (Gel Permeation Chroma)
The measurement is 150 pieces manufactured by Waters.
A C-type GPC measuring device is used and the column has a GM manufactured by Tosoh Corporation.
H6-HT, using o-dichlorobenzene as a solvent,
It was measured at 5 ° C. The calibration curve was prepared by a standard method using standard polystyrene manufactured by Tosoh Corporation. Molecular weight distribution (Q value)
Was calculated as the ratio of weight average molecular weight / number average molecular weight.

(5) Heat-sealing property (HS) The ethylene / α-olefin copolymer layers of two composite films cut into a width of 15 mm are superposed on each other, and the sealing surface pressure is applied using a heat sealer manufactured by Tester Sangyo Co., Ltd. Heat sealing was performed with a seal width of 10 mm under the conditions of 1.0 kg / cm ² and a sealing time of 1.0 second. Heat sealing was performed in the same manner by changing the temperature of the seal bar by 5 ° C. From this, a test piece having a width of 15 mm was cut out in a direction perpendicular to the sealing surface, and 180 ° peel strength was measured at a speed of 200 mm / min using a Shopper type tensile tester. The seal strength is
The seal strength measured under the above conditions shall be the maximum value, and the low temperature heat sealability shall be 5k for the seal strength measured under the above conditions.
The minimum temperature when the width exceeds g / 15 mm is shown.

(6) n-Hexane-insoluble matter was measured according to the method described in FDA Standard, Chapter 177, Section 1520. Specifically, resin 2.5 ± 0.00
1 g was placed in a flask, 1000 ml of n-hexane was added, and the flask was placed in a water bath adjusted to 50 ° C. in advance and heated. After the temperature of n-hexane in the flask reached 50 ° C., the mixture was left for exactly 2 hours while stirring with a magnetic stirrer. afterwards,
While the n-hexane was warm, natural filtration was performed using a filter paper. The filtrate was collected in a flask that had been precisely weighed in advance, and the recovered filtrate was weighed. As a result, the recovered filtrate was recovered in 90% or more of the initial charged amount. Next, about half of the solvent filtrate was transferred to a 1-liter beaker, and heated and concentrated using a steam bath. High-purity nitrogen gas was blown into the beaker during the concentration. When the amount of solvent in the beaker had decreased due to evaporation, the remaining solvent filtrate was further added, and finally all the solvent filtrate was transferred. When the concentrate had reached approximately 50 ml, it was transferred to a pre-weighed 100 ml evaporating dish. The beaker was washed twice with warm n-hexane and the wash was added to the same evaporation dish. The evaporation dish was further concentrated by a steam bath under a stream of high-purity nitrogen, and finally all the solvent was evaporated. The evaporation dish containing the residue was transferred to a vacuum desiccator and allowed to stand for 12 hours or more, after which the net weight of the dried residue was weighed with an accuracy of 0.0001 g. The results were corrected with blank test values corresponding to the non-volatile substances in n-hexane used in the test. From the result of the above method, the n-hexane soluble content was calculated by the following formula. n-Hexane soluble content (wt%) = {residue weight (g) / sample weight (g)} × 100

(I) Preparation of ethylene / α-olefin copolymer composition and production of monolayer film Ethylene / α-olefin copolymer pellets were dry blended at a predetermined mixing ratio to obtain a die width of 400 mm and a die lip of 0. Using a Tanabe Plastics film forming machine consisting of a 0.7 mm T-die and a 50 mmφ single screw extruder, a film with a thickness of 50 μm at an extrusion speed of 10 kg / hr, a die setting temperature of 240 ° C. and a chill roll temperature of 75 ° C. Got Furthermore, the surface tension of the film surface is 42 to 45 dyne / by the corona treatment machine attached to the device.
Corona treatment was performed so as to be cm.

(II) Manufacture of Composite Film Using a Yasui Seiki tabletop test coater, the above-mentioned ethylene / α-olefin copolymer composition single layer film was prepared.
Thickness 1 with urethane adhesive applied to achieve 2g / m ²
Stretched nylon substrate film of 5μm, 40 ℃, 3kg
After being pressure-bonded at / cm ² , the mixture was heat-aged at 40 ° C. for 2 days to obtain a dry lamination composite film.

Examples 1 to 4 and Comparative Examples 1 to 4 Ethylene / α-olefin copolymer pellets were formed into a film by the above method. The density and n-hexane insoluble content of the film were measured. Further, this film was attached to a stretched nylon base material by the dry lamination method by the above-mentioned method, and then the heat sealability was evaluated. The results are shown in Tables 1 and 2.

Examples 5 to 7 and Comparative Example 5 Ethylene / α-olefin copolymer pellets were mixed at a predetermined ratio and formed into a film by the above-mentioned method. The density and n-hexane insoluble content of the film were measured. Furthermore, after laminating this film on the stretched nylon base material by the dry lamination method by the above-mentioned method,
The heat sealability was evaluated. The results are shown in Table 3.

[0048]

[Table 1] −−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 1 2 3 4 types * 1 A1 A2 A3 A4 Characteristic density g / cm ³ 0.902 0.900 0.897 0.905 MFR g / 10 min 2.0 4.0 2.2 1.9 Number average molecular weight 96 100 75 200 93 800 96 900 Molecular weight distribution 2.0 2.0 2.0 2.0 Maximum peak temperature ℃ 92 91 86 95 n-Hexane solubles wt% 0.57 0.98 3.29 0.51 Heat seal manifestation temperature ℃ 108 107 103 110 --------------------------------

[0049]

[Table 2] −−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 1 2 3 4 types * 1 A5 A6 A7 A8 Characteristic density g / cm ³ 0.885 0.892 0.905 0.915 MFR g / 10 min 2.0 2.2 2.1 1.7 Number average molecular weight 95800 93400 57600 99800 Molecular weight distribution 2.1 2.0 4.1 2.0 Maximum peak temperature ℃ 65 81 115 109 n-hexane soluble content wt% 88.5 26.6 7.60 0.35 Heat seal development temperature ° C 102 102 124 122 ----------------------------------

[0050]

[Table 3] −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Actual Example Comparative Example 5 6 7 5 Component 1 type * 1 A1 A1 A9 A8 Characteristic density g / cm ³ 0.902 0.902 0.910 0.902 MFR g / 10 min 2.0 2.0 2.0 2.0 Number average molecular weight 96 100 96 100 96 300 96 100 Molecular weight distribution 2.0 2.0 1.8 2.0 Maximum peak temperature ℃ 92 92 102 92 Usage wt% 60 20 90 40 components 2 types * 1 A5 A6 A10 A5 Characteristic density g / cm ³ 0.885 0.892 0.879 0.885 MFR g / 10 min 2.0 2.2 4.7 2.0 Number average molecular weight 95800 93400 72200 95800 Molecular weight distribution 2.1 2.0 2.0 2.1 Maximum peak temperature ℃ 65 81 62 65 Amount used wt% 40 80 10 60 Density of composition g / cm ³ 0.897 0.895 0.907 0.892 n-hexane soluble content wt% 3.24 4.22 5.80 12.5 Heat seal temperature ℃ 102 102 110 102 −−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−

* 1 Ethylene / α-olefin copolymer A1, A2, A4 to A8: ethylene-butene-1 copolymer A3, A9, A10: ethylene-hexene-1 copolymer A1 to A3, A5 and A6 Were produced by a solution polymerization method using a vanadium catalyst. A4, A8 ~
All of A10 were produced by a solution polymerization method using a metallocene catalyst. A7 was produced by a high pressure ionic polymerization method using a titanium-based catalyst.

[0052]

EFFECT OF THE INVENTION The food packaging film of the present invention is characterized in that it has a low temperature at which heat sealability is exhibited and has a low extractability with respect to a hydrocarbon solvent, and further has transparency, gloss, impact strength and tear strength. Excellent balance of physical properties such as
It satisfies all important properties as a film for food packaging. This film is konjac in the form of a monolayer film or a composite film, foods packaged with water like pickles, milk, liquor, liquid foods such as soy sauce, dried foods such as confectionery, It can be used for packaging various foods such as packaging of processed meat such as ham and sausage.

Claims (4)

[Claims] 1. Ethylene and α-having 3 to 12 carbon atoms
Made of olefin and has a melt flow rate of 0.5-3
It is 0 g / 10 minutes, the number average molecular weight measured by the GPC method is 35,000 to 150,000, and the molecular weight distribution represented by the ratio of weight average molecular weight / number average molecular weight is 1.8 to 3.0. And the maximum melting peak temperature measured by a differential scanning calorimeter is in the range of 60 to 110 ° C. and the ethylene / α-olefin copolymer and the mixture thereof have a density of 0.895 to 0.910 g / cm ³
And the n-hexane-soluble content is 6% by weight or less, a film for food packaging. 2. A mixture of ethylene / α-olefin copolymers is a mixture of two kinds of ethylene / α-olefin copolymers having only one melting peak by a differential scanning calorimeter, and a density of 0. 860 to 0.900 g / cm ³ ethylene / α-olefin copolymer and density 0.900
The food packaging film according to claim 1, which is a mixture of ethylene / α-olefin copolymers exceeding g / cm ³ . 3. The food packaging film according to claim 1, which is obtained by polymerizing an ethylene / α-olefin copolymer with a metallocene catalyst. 4. An α-of an ethylene / α-olefin copolymer
The food packaging film according to claim 1, wherein the olefin is 1-hexene.