JPH08286320A - Packaging film for photosensitive material - Google Patents

Abstract

PURPOSE: To provide a packaging film for photosensitive material which is not only excellent in light shielding property, tearing strength, and impact resisting strength, but also enhanced in low temperature heat sealing property and excellent in slip characteristic and blocking resistance characteristic without the stickiness of the film surface. CONSTITUTION: In a laminated film containing a light shielding layer (A) formed of a composition consisting of an ethylene copolymer and a light shielding material and a heat sealing layer (B), the heat sealing layer (B) consists of a layer mainly containing a copolymer of ethylene and an α-olefin having 3 or more carbon atoms which is manufactured by use of a metallocene polymerized catalyst and has a melt flow rate MFR of 0.1-10g/10mins. and a density of 0.88-0.93g/cm<3> under 190 deg.C and a load of 2.1kg according to ASTM D1238-65T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film for packaging a light-sensitive material, and more specifically, it has excellent heat-sealing property, good slip property, and high impact strength and tear strength.
The present invention relates to a film for packaging a photosensitive material, which has a good light-shielding property and a good appearance when packaged.

[0002]

2. Description of the Related Art Conventionally, a laminated film comprising a composition layer in which a light-shielding material such as carbon black is blended with polyolefin and a heat-sealing layer mainly containing an ethylene-α-olefin copolymer is used as a film for packaging a photosensitive material. This is known (Japanese Patent Laid-Open No. 62-18548).

It is also known to use a diagonally oriented polyolefin laminated film in which two polyolefin films having a molecular orientation in a certain oblique direction are laminated so that their molecular orientations intersect each other for packaging a photosensitive material ( JP-A-6
-57053).

However, the conventionally known ethylene-α-
When an olefin copolymer is used as the heat-sealing layer of such a film for packaging a light-sensitive material, there is a problem that the oblique orientation base material film shrinks when the heat-sealing temperature is raised and the appearance of the packaging bag is deteriorated.

However, in order to lower the heat seal temperature, the density of the heat seal layer is 0.92 g / cm.
^{When a} copolymer having a low density of ³ or less, and thus a low melting point of 110 ° C. or less is used, in this case, a copolymer produced using a conventional titanium-based catalyst has a low density (low melting point) of such a copolymer. The polymer causes stickiness at the time of forming the film, causes so-called blocking between films, and also causes a problem that wrinkles are generated due to poor sliding of the film,
A low melting point polymer could not be used because of the problem of high defective rate during production.

Since the ethylene-α-olefin copolymer obtained by such a conventional Ti catalyst has a high low melting point, there is a problem that the width of the heat sealing temperature is narrow, which makes the heat sealing operation difficult and It also causes an increase in the defective rate.

Attempts have been made to add additives such as a slip agent to the heat-sealing layer for the purpose of improving the blocking property and slip property described above. Since the slip agent is often precipitated near the exit of the die and the molding must be interrupted to remove the precipitate, and the effect of adding a large amount is slight, and improvement thereof has been desired.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a light-sensitive material which has a low heat-sealing start temperature and a high heat-sealing strength and a good slip property as well as a high impact strength and tear strength. To provide a packaging film. A second object of the present invention is that the moldability is good,
Another object of the present invention is to provide a film for packaging a light-sensitive material with less trouble during molding.

A third object of the present invention is to provide a film for packaging a photosensitive material which is excellent in light-shielding property, has a wide heat-sealing temperature range, and has a good appearance of a packaging bag after heat-sealing.

[0010]

According to the present invention, a laminated film containing a light-shielding layer (A) and a heat-sealing layer (B) formed of a composition comprising an ethylene polymer and a light-shielding material, Heat seal layer (B) is ASTM D
According to 1238-65T, the melt flow rate (MFR) at 190 ° C. and a load of 2.16 kg is 0.1 to 10 g.
/ 10 minutes, a layer containing as a main component a copolymer of ethylene and an α-olefin having 3 or more carbon atoms, which is produced using a metallocene polymerization catalyst having a density of 0.88 to 0.93 g / cm ^3. A characteristic film for packaging a photosensitive material is provided.

[0011]

The film for packaging a light-sensitive material of the present invention is mainly composed of an ethylene-α-olefin copolymer having specific physical properties, which is polymerized by using a metallocene polymerization catalyst as a heat-sealing layer of a laminated film constituting the film. The use of resin is a characteristic feature of the construction.

The ethylene-α-olefin copolymer polymerized by using the metallocene-based polymerization catalyst has a narrow composition distribution of the copolymer polymer, and the proportion of the low-molecular-weight fraction having a low melting point is different from that of the other polymerization catalyst. Remarkably less than polymerized copolymer.

Further, the ethylene-α-olefin copolymer produced by the multistage polymerization method using the metallocene polymerization catalyst of the present invention is a Ziegler composed of another polymerization catalyst such as a titanium compound and an organoaluminum compound. Unlike copolymers polymerized using a system catalyst, etc., the average value of the degree of branching of molecules in the fraction of the low molecular weight side in the copolymer, Bl
However, it has a remarkable feature that it is smaller than the average value Bh of the branching degree of the molecules in the high molecular weight fraction. Therefore, surface stickiness and blocking between films are reduced. Therefore, a film having good slip characteristics can be obtained without adding a large amount of lubricant or the like.

The composition of the present invention obtained by blending a copolymer having a specific melt flow rate and a specific density polymerized by using the metallocene catalyst with low density polyethylene polymerized by a high pressure method is The composition polymer has a large melt tension and an excellent hot tack property, and has advantages that the heat-sealed portion becomes thick and the heat-sealing strength becomes large even in low-temperature heat-sealing.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the film for packaging a light-sensitive material of the present invention will be described more specifically below. The packaging film according to the present invention is mainly composed of a light-shielding layer (A) formed of a composition comprising an ethylene-based polymer and a light-shielding material, and a specific ethylene-α-olefin copolymer having 3 or more carbon atoms. And a heat seal layer.

Examples of the ethylene-based polymer forming the light-shielding layer (A) include high-density polyethylene, high-pressure low-density polyethylene, ethylene and another α-olefin, preferably an α-olefin having 3 to 20 carbon atoms. Examples thereof include polymers and compositions comprising these resins. Examples of α-olefins used for copolymerization other than ethylene include propylene, 1-butene, 1-pentene, 1-hexene,
Mention may be made of 4-methyl-1-pentene, 1-octene and mixtures thereof.

Of these ethylene polymers, 19
Melt florate (MFR) measured at 0 ° C. under a load of 2.16 kg is 0.5 to 10 g / 10 minutes, and the density is 0.
90 to 0.935 g / cm ³ ethylene-α-olefin copolymer and a melt flow rate (MFR) of 0.0
1 to 0.5 g / 10 minutes, density 0.94 to 0.97
Composition with high density polyethylene of g / cm ³ is flexible,
It is preferable in that it has excellent tear strength, impact strength and the like.

In this composition, when the MFR of the ethylene-α-olefin copolymer component is less than 0.5 g / 10 minutes, the fluidity in the film molding becomes poor and the resulting film also has poor compatibility. There is a shark skin and a tingling sensation on the appearance, and pinholes are likely to occur.

On the other hand, when the MFR exceeds 10 g / 10 minutes, the fluidity tends to be slightly improved in the film molding, but the elongation and the tension at the time of melting are small and the moldability is poor, and the obtained film is also particularly torn. The strength, impact strength, and heat seal strength tend to be poor. On the other hand, if the density is less than 0.90 g / cm ³ , the viscosity during film formation is high and stickiness is large, the motor load of the extruder is large, and the moldability tends to be significantly deteriorated.

On the other hand, when the density exceeds 0.935, the film moldability is slightly deteriorated, and the physical properties such as tear strength, impact strength and tensile strength of the obtained film tend to be poor. The copolymer having the above properties, for example,
It can be obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms by a low pressure method in the presence of a Ziegler catalyst or a metallocene catalyst described later.

From the viewpoint of improving the impact resistance of the light-shielding layer film, α-olefins having 4 to 20 carbon atoms are preferable, and α-olefins having 6 to 16 carbon atoms are particularly preferable. The content of α-olefin in the ethylene-α-olefin copolymer is usually 0.1 to 30 mol%, preferably 0.5 to 20 mol%, more preferably 1 to 10 mol%. When the MFR of the high density polyethylene, which is the other component of the composition, is less than 0.01 g / 10 minutes,
There is a tendency that the fluidity in film formation deteriorates, the viscosity during melting is high, stickiness occurs, and the moldability deteriorates.

On the other hand, when the MFR exceeds 0.5 g / 10 minutes, the fluidity at the time of film molding is slightly improved, but the elongation and tension at the time of melting are small, and the moldability tends to deteriorate.
If the density is less than 0.94 g / cm ³ , the elongation (elasticity) of the film when melted will be small and the formability will be poor, and the tear strength, impact strength and tensile strength of the resulting film will tend to be poor. is there.

On the other hand, if the density exceeds 0.97 g / cm ³ , the elongation and tension at the time of melting in film molding tend to be slightly improved, but the heat seal strength of the obtained film tends to be poor. Further, this high-density polyethylene has a Q value (weight average molecular weight Mw / number average molecular weight Mn) of 20.
Above all, it is particularly desirable that the range is 25 to 30.

Here, the Q value is an index representing a measure of the molecular weight distribution, and its measurement is carried out by gel permeation chromatography to obtain a molecular weight distribution curve, and a monodisperse polystyrene having a known molecular weight is used as a standard by the universal calibration method. It is a value obtained by calculating the weight average molecular weight and the number average molecular weight. By using high-density polyethylene having a Q value in the above range as a component resin of the composition for a light-shielding layer, a film layer having good moldability and mechanical strength can be obtained.

The high-density polyethylene having the above-mentioned properties is polymerized under low pressure using a conventionally known Ziegler catalyst typified by a composite catalyst of a titanium compound supported on a magnesium compound and an organometallic compound. And a method of polymerizing under a medium pressure using a Phillips catalyst typified by a chromium oxide catalyst using silica-alumina as a carrier.

The blending ratio of the ethylene-α-olefin copolymer component and the high-density polyethylene in the light-shielding layer composition is 10 to 80% by weight, preferably 20 to 70% by weight, and particularly 30 to 60% by weight. On the other hand, the latter is preferably compounded in an amount of 90 to 20% by weight, preferably 80 to 30% by weight, and particularly preferably 70 to 40% by weight. By blending in such a compounding ratio, mechanical properties such as tear strength and impact strength are improved. An excellent film can be obtained.

In the present invention, examples of the light-shielding material blended in the light-shielding resin layer (A) include metal powder and carbon black. Examples of the metal powder include aluminum powder, tin powder, gold powder, silver powder and the like, and these may be surface-treated with fatty acids such as stearic acid and oleic acid.

Carbon black includes gas black, oil furnace black, anthracene black, acetylene black, channel black, oil smoke,
Examples include pine smoke, animal black, vegetable black and the like, and of these, furnace black and acetylene black are preferable. The blending amount of these light shielding materials is 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight in the case of metal powder, per 100 parts by weight of the resin component of the light shielding layer.
In the case of carbon black, 2 to 10 parts by weight, preferably 3
It is compounded in a ratio of 5 parts by weight.

In the film for packaging a light-sensitive material of the present invention, as a laminated structure including a light-shielding layer, two ethylene polymer films having a molecular orientation in a certain oblique direction are laminated so that their molecular orientations cross each other. In addition, it is preferable that at least one of the two laminated films is composed of an obliquely compounded ethylene polymer laminated film in which a light shielding material is compounded and a heat seal layer. The angle of intersection of the molecular orientation axes of the two obliquely oriented films in the longitudinal direction is usually 30 to
It is 150 degrees, preferably 60 to 120 degrees. Those having such a diagonally oriented cross film as a light-shielding layer structure are particularly excellent in tear strength and falling weight impact strength, and can prevent the occurrence of pinholes.

A raw film stretched so that the orientation ratio of the original film (tensile strength of stretched film / tensile strength of unstretched film) is usually 1.2 times or more, preferably about 1.5 times to 5 times. It is better to use. Among the obliquely-oriented laminated films including such a light-shielding layer, those in which carbon black is blended in the layer facing the heat seal layer and titanium oxide is blended in the other layer are more preferable. The packaging film of this aspect has an advantage that it is convenient to handle a packaged product in which a light-sensitive material is encapsulated in a dark place.

The compounding amount of titanium oxide is the resin component 1 of the layer.
It is 1 to 10 parts by weight, preferably 2 to 5 parts by weight, per 00 parts by weight. For laminating such obliquely oriented cross film layers, various methods known per se, such as a dry laminating method, an extrusion laminating method, or a hot melt laminating method, can be used. Moreover, a circularly oriented film can be obtained by relatively rotating the circular die and the pulling roll. By using the obliquely oriented film forming apparatus described in JP-B-47-38621 or JP-B-53-38306, a direct laminated cross film can be obtained.

The heat-sealing layer of the film for packaging a light-sensitive material of the present invention contains, as a main component, a copolymer of ethylene and an α-olefin having 3 or more carbon atoms, which is produced by a metallocene catalyst. ASTM of the copolymer that can be used in the present invention
The melt flow rate MFR at 190 ° C. under a load of 2.16 kg specified by D1238 is 0.1 to 10, preferably 0.5 to 5 g / 10 minutes, and the density is 0.88 to
0.93 gcm ^3, preferably 0.89 to 0.92 g
cm ^3, and in particular in the range of 0.90~0.92gcm ^3. If the melt flow rate is higher than the above range, the impact strength, tear strength and heat seal strength of the obtained film are lowered, which is not preferable. Further, if the density is higher than the above range, the heat sealing start temperature becomes high, which is not preferable.

The Mw / Mn of this copolymer measured by gel permeation chromatography (GPC).
Is 1.5 to 7, the average branching degree of the high molecular weight fraction measured using GPC-IR is Bh, and the branching degree of the low molecular weight side is Bl, the following formula (I) BR = Bh It is preferable that / Bl> 1 (I) holds. The high molecular weight fraction and the low molecular weight fraction referred to in the present application are GP
The peak of the highest concentration of the fraction measured by C is centered on the higher molecular weight side and the lower molecular weight side.
A fraction divided into two. The average branching degree is the arithmetic average of the branching degree values of each fraction. In this case, 5% of the low molecular weight side and 5% of the high molecular weight side of the fraction were cut.

Further, it is preferable that there are two or more peaks of the heat of fusion curve obtained by a differential scanning calorimeter (DSC) of the copolymer forming the main component of the heat seal layer. The molecular weight distribution (Mw / Mn) is GPC manufactured by Millipore.
It measured using -150C as follows. The separation column is TSK GNH HT, the column size is 72 mm in diameter, 600 mm in length, and the column temperature is 1
40 ° C., 0-dichlorobenzene (Wako Pure Chemical Industries) as mobile phase and BHT (Takeda) as antioxidant
0.025% by weight, moving at 1.0 ml / min,
The sample concentration was 0.1% by weight, the sample injection amount was 500 microliters, and a differential refractometer was used as a detector.
Standard polystyrene has a molecular weight of Mw <1000 and M
For w> 4 × 10 ⁶ , manufactured by Tosoh Corporation is used, and 1000
For <Mw <4 × 10 ⁶ , a product manufactured by Pressure Chemical Co. was used. Further, it is preferable that there are two or more peaks of the heat of fusion curve obtained by a differential scanning calorimeter (DSC) of the copolymer forming the main component of the heat seal layer.

The copolymer of ethylene and α-olefin having 3 or more carbon atoms used in the heat-sealing layer of the present invention is a random copolymer of ethylene and α-olefin. The carbon number of the α-olefin copolymerized with ethylene is preferably in the range of 3 to 20, and specific examples of such α-olefin include propylene and 1
-Butene, 1-pentene, 1-hexene, 4-methyl 1
-Pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like.

In the copolymerization composition of this copolymer, the constitutional unit derived from ethylene is present in an amount of 55 to 99% by weight, preferably 65 to 98% by weight, more preferably 70 to 96% by weight, and carbon. The structural unit derived from the α-olefin of the number 3 to 20 is 1 to 45% by weight, preferably 2 to 3
It is desirable to be present in an amount of 5% by weight, more preferably 4-30% by weight. This copolymer has an intrinsic viscosity [η _A ] of 1.0-10.
It is desirable to be in the range of 0 dl / g, preferably 1.25 to 8 dl / g, and more preferably 1.27 to 6 dl / g. Further, it is preferable that the melt tension (MT (g)) and the melt flow rate (MFR) satisfy the relationship of MT> 2.2 × MFR ^−0.84 .

The composition of the ethylene-α-olefin copolymer is usually about 200 in a 10 mmφ sample tube.
A ¹³ C-NMR spectrum of a sample in which mg of the copolymer was uniformly dissolved in 1 ml of hexachlorobutadiene was measured at a measurement temperature of 120 ° C., a measurement frequency of 25.05 MHz, a spectrum width of 1500 Hz, a pulse repetition time of 4.2 sec, and a pulse width of 6 μsec. It is determined by measuring under the measurement conditions of.
The density (d) was measured by measuring the melt flow rate (MFR) at 190 ° C. under a load of 2.16 kg, heat-treating the strand at 120 ° C. for 1 hour, gradually cooling it to room temperature over 1 hour, and then measuring the density gradient. Determined by measuring with a tube.

Further, the peak of the endothermic curve measured by a differential scanning calorimeter (DSC) was such that about 5 mg of a sample was packed in an aluminum pan, heated to 200 ° C. at 10 ° C./min, and kept at 200 ° C. for 5 minutes. It is obtained from the endothermic curve when the temperature is lowered to room temperature at 20 ° C./min and then the temperature is raised at 10 ° C./min.
For the measurement, a Perkin Elmer DSC-7 type device was used.

The melt tension (MT (g)) is determined by measuring the stress when the melted polymer is stretched at a constant rate. That is, the produced polymer powder is melted by a usual method and then pelletized to obtain a measurement sample. Using an MT measuring instrument manufactured by Toyo Seiki Seisakusho, a resin temperature of 190 ° C., an extrusion speed of 15 mm / min, and a winding speed of 10 to 20 m /
Min, the nozzle diameter is 2.09 φ mm, and the nozzle length is 3 mm. At the time of pelletizing, the ethylene-α-olefin copolymer was previously mixed with 0.05% by weight of tri (2,4-di-t-butylphenyl) phosphate as a secondary antioxidant and as a heat resistance stabilizer. 0.1% by weight of n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-t-butylphenyl) propionate and 0.05% by weight of calcium stearate as a hydrochloric acid absorbent were added.

The metallocene polymerization catalyst used for the copolymerization of the ethylene-α-olefin copolymer, which is the main component resin constituting the heat-sealing layer of the present invention, will be specifically described below. This copolymerization catalyst comprises, as a catalyst and a carrier component, (a) a transition metal compound of Group iv of the periodic table containing a ligand having a cyclopentadienyl skeleton, (b) an organoaluminum oxy compound, (c) a carrier. Is an essential component, and preferably (d) an organoaluminum compound. The transition metal compound of component (a) (hereinafter sometimes referred to as “component (a)”) is a transition metal compound represented by the following formula [I]. R ² _K R ³ _L R ⁴ _m R ⁵ _n M [I] (In the formula, M is the above transition metal, and R ² is a group having a cyclopentadienyl skeleton in which a hydrocarbon group may be substituted (ligand And R ³ , R ⁴ and R ⁵ are groups having a cyclopentadienyl skeleton in which a hydrocarbon group may be substituted, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a trialkyl group. It is a silyl group, an SO ₃ R group, a halogen atom or a hydrogen atom, k is an integer of 1 or more, and k + 1 + m + n = 4.)

In the present invention, in the above general formula, R ² , R
^At least two of ³ , R ⁴ and R ⁵ , ie R ²
A metallocene compound in which R ³ and R ³ are groups (ligands) having a cyclopentadienyl skeleton in which a hydrocarbon group can be substituted is preferably used. Groups having these cyclopentadienyl skeletons include alkylene groups such as ethylene and propylene, substituted alkylene groups such as isopropylidene and diphenylmethylene, silylene groups or substituted silylene groups such as dimethylsilylene, diphenylsilylene and methylphenylsilylene groups. It may be connected via. R ⁴ and R ⁵ are a group having a cyclopentadienyl skeleton, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a trialkylsilyl group, SO ₃ R, a halogen atom or a hydrogen atom. is there.

The substituted cyclopentadienyl group may have two or more substituents, and the two or more substituents may be the same or different. The substituted cyclopentadienyl group has at least 1 when it has two or more substituents.
The number of the substituents may be a hydrocarbon group having 3 to 10 carbon atoms, and the other substituents may be a methyl group, an ethyl group or a carbon number 3
10 to 10 hydrocarbon groups. Further, the substituted cyclopentadienyl groups coordinated to M may be the same or different.

Specific examples of the hydrocarbon group having 3 to 10 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group and an aralkyl group. More specifically, n-propyl group, isopropyl group, n-butyl group,
Isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group, alkyl group such as decyl group, cyclopentyl group, cycloalkyl group such as cyclohexyl group, phenyl group,
Examples thereof include an aryl group such as a tolyl group and an aralkyl group such as a benzyl group and a neofil group. Of these, alkyl groups are preferable, and n-propyl group and n-butyl group are particularly preferable.

In the present invention, coordination with a transition metal (substitution)
The cyclopentadienyl group is preferably a substituted cyclopentadienyl group, more preferably a cyclopentadienyl group substituted with an alkyl group having 3 or more carbon atoms, further preferably a disubstituted cyclopentadienyl group, 1,3 The -substituted cyclopentadienyl group is particularly preferred.

When the compound represented by the general formula [I] contains two or more groups having a cyclopentadienyl skeleton, the two groups having a cyclopentadienyl skeleton among them are ethylene, propylene. Alkylene groups, such as
It may be bonded via a substituted alkylene group such as isopropylidene or diphenylmethylene, a silylene group or a dimethylsilylene group, a substituted silylene group such as a diphenylsilylene group or a methylphenylsilylene group.

Specific examples of the ligand other than the ligand having a cyclopentadienyl skeleton include the following. A hydrocarbon group having 1 to 12 carbon atoms, specifically, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and the like can be given. More specifically, the alkyl group can be a methyl group, an ethyl group, a propyl group, Examples include isopropyl group and butyl group, examples of cycloalkyl group include cyclopentyl group and cyclohexyl group, examples of aryl group include phenyl group and tolyl group, and examples of aralkyl group include benzyl group and neophyll group. Examples include groups. Further, as the alkoxy group,
A methoxy group, an ethoxy group, a butoxy group and the like are exemplified, and an aryloxy group is exemplified by a phenoxy group and the like,
Examples of halogen include fluorine, chlorine, bromine, iodine and the like. As the ligand represented by SO ₃ R, p-
Examples thereof include a toluene sulfonate group, a methane sulfonate group, and a trifluoro methane sulfonate group.

Examples of these transition metal compounds represented by the general formula [I] include bis (n-propylcyclopentadienyl) zirconium dichloride, bis (n-butylcyclopentadienyl) zirconium dichloride and bis (1 -Methyl-3-n-propylcyclopentadienyl) zirconium dichloride, bis (1-methyl-3-)
n-butylcyclopentadienyl) zirconium dichloride, bis (trimethylcyclopentadienyl) zirconium dichloride, bis (tetramethylcyclopentadienyl) zirconium dichloride, bis (pentamethylcyclopentadienyl) zirconium dichloride, bis (hexylcyclo) Pentadienyl) zirconium dichloride, bis (trimethylsilylcyclopentadienyl)
Examples thereof include zirconium dichloride and the like.

Next, the organoaluminum oxy compound (b) will be described. The organoaluminum oxy compound (b) (hereinafter sometimes referred to as “component (b)”) used in the present invention may be a conventionally known benzene-soluble aluminoxane, and can be used in JP-A-2- 27
It may be a benzene-insoluble organoaluminum oxy compound as disclosed in Japanese Patent No. 6807. In the metallocene polymerization catalyst of the present invention, the above essential catalyst component, or the catalyst component to which the organoaluminum compound (d) is further added, is preferably carried on the carrier (c) to give a polymerization catalyst.

The carrier (c) used in the present invention (hereinafter sometimes referred to as "component (c)") is an inorganic or organic compound having a particle size of 10 to 300 μm, preferably 20 to 200 μm. Granules or finely divided solids are used. Of these, porous oxides are preferable as the inorganic carrier, and specifically, SiO ₂ , Al ₂ O ₃ , MgO,
ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, Ba
O, ThO ₂ etc. or mixtures thereof, eg SiO _{2
-MgO, SiO 2 -Al 2 O 3} , SiO 2 -Ti
_{O 2, SiO 2 -V 2 O} 5, SiO 2 -Cr 2 O 3, S
Examples thereof include iO ₂ —TiO ₂ —MgO.
Of these, those containing, as a main component, at least one component selected from the group consisting of SiO ₂ and Al ₂ O ₃ .

Such carrier (c) has different properties depending on its type and production method, but the carrier preferably used in the present invention has a specific surface area of 50 to 1000 m ² / g, preferably 1
0 to 700 m ² / g and a pore volume of 0.3 to 2.
It is preferably 5 m ² / g. The carrier is, if necessary, 100 to 1000 ° C., preferably 150 to 700.
It is used after firing at ℃.

Further, the carrier (c) which can be used in the present invention includes a granular or fine particle solid of an organic compound having a particle size of 10 to 300 μm. As these organic compounds, (co) polymers or vinylcyclohexane, styrene produced mainly from α-olefins having 2 to 14 carbon atoms such as ethylene, propylene, 1-butene and 4-methyl-1-pentene. The polymer or copolymer produced by using as a main component can be exemplified. The catalyst used in the present invention is formed of the above-mentioned (a) transition metal compound, (b) organoaluminum oxy compound and (c) carrier, but (d) organoaluminum compound may be used if necessary.

Examples of the (d) organoaluminum compound (hereinafter sometimes referred to as “component (d)”) that is used as necessary include, for example, the organoaluminum compounds represented by the following general formula [IV]. can do. R ¹ _n AlX _3-n [IV] (In the formula [IV], R ¹ is a hydrocarbon group having 1 to 12 carbon atoms, X is a halogen atom or a hydrogen group, and n is 1 to _3. ) In the above general formula [IV], R ¹ is a hydrocarbon group having 1 to 12 carbon atoms such as an alkyl group, a cycloalkyl group or an aryl group, and specifically, a methyl group, an ethyl group, n
-Propyl group, isopropyl group, isobutyl group, pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group and the like.

Such an organoaluminum compound (d)
Specific examples of the compound include the following compounds: trialkylaluminum such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, and tri-2-ethylhexylaluminum; alkenyl such as isoprenylaluminum. aluminum.
The catalyst used in the production of the above ethylene-α-olefin copolymer has a transition metal atom derived from the component (a) per 1 g of the component (c) of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ gram atom, It is preferably supported in an amount of 10 ^{−5 to} 2 × 10 ⁻⁴ gram atom, and 10 ^{−3 to} 5 × 1 of aluminum atom derived from the component (b) and the component (d) per 1 g of the component (c).
It is desirable to support in an amount of 0 ^-2 gram atom, preferably 2 x 10 ^-3 to 2 x 10 ^-2 gram atom.

The ethylene-α-olefin copolymer, which is the main component of the heat-sealing layer of the present invention, is obtained by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms in the presence of the metallocene polymerization catalyst. It is obtained by doing.

In the present invention, the copolymerization of ethylene and α-olefin is preferably carried out in a gas phase or in a slurry liquid phase. In the slurry polymerization, an inert hydrocarbon may be used as a solvent or an olefin. The solvent itself can also be used. Inert hydrocarbon solvents include butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane, octadecane and other aliphatic hydrocarbons; cyclopentane, methylcyclopentane, cyclohexane, cyclooctane and other alicyclic hydrocarbon solvents Hydrocarbons; aromatic hydrocarbons such as benzene, toluene and xylene; petroleum fractions such as gasoline, kerosene, and light oil can be exemplified.

In the present invention, the copolymerization of ethylene and the α-olefin is carried out in two steps of prepolymerization and main polymerization so that the activation of the catalyst and the properties of the produced copolymer particles and the polymerization activity can be confirmed. More preferable from both sides, the prepolymerization is carried out by introducing ethylene or a mixed olefin of ethylene and α-olefin in an inert hydrocarbon solvent in the presence of a catalyst as described above to obtain a relatively small amount of the polymer. To be achieved.

The olefin polymer produced by the prepolymerization is
It is desirable that the amount is 0.1 to 500 g, preferably 0.2 to 300 g, and more preferably 0.5 to 200 g per 1 g of the carrier (c). In the prepolymerization catalyst, the component (a) per gram of the carrier (c) is about 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ gram atom, preferably 10 ⁻⁵ , as a transition metal atom.
Aluminum atom (Al), which is supported in an amount of ˜2 × 10 ⁻⁴ gram atom and is derived from the component (b) and the component (d).
Is a molar ratio (Al / M) to the transition metal atom (M) derived from the component (a), and is 5 to 200, preferably 10.
It is desirable that the amount is carried in the range of 150. When such preliminary polymerization is achieved, the above-mentioned copolymerization is carried out as a main polymerization step.

The heat seal layer of the present invention is the MF described above.
The ethylene-α-olefin copolymer alone may have a layer of R0.1 to 10 and a density of 0.88 to 0.93 g / cm ³ , and may be composed of the ethylene-α-olefin copolymer [A]. MFR1-100, density 0.90-0.94g
/ Cm ³ of the ethylene-α-olefin copolymer [B], and the ethylene-α-olefin copolymer [A] is 5 to 95% by weight, preferably 10 to 90% by weight, particularly preferably 30 to 70% by weight of ethylene-α-olefin copolymer [B] is 5 to 95% by weight, preferably 10 to 90%.
It is more preferred that the copolymer composition is contained in an amount of 70% by weight, particularly 70 to 300% by weight.

In this copolymer composition, the average molecular branching degree Bl of the low molecular weight fraction in the copolymer is smaller than the average molecular branching degree Bh of the high molecular weight fraction. In addition, there are two or more peaks of the heat of fusion curve measured by the above DSC, and the Mw / Mn value is larger than that of a single copolymer, so that it is easy to mold and has good slip properties The sealing start temperature is low, the heat sealing strength is high, and the temperature range in which the laminated film can be heat sealed is expanded.

Ethylene-α-olefin copolymer [A]
And the ethylene-α-olefin copolymer [B] are the ratio of the density of the ethylene-α-olefin copolymer [A] and the density of the ethylene-α-olefin copolymer [B] ([A ] / [B]) is less than 1, preferably 0.930-
It is used in combination so as to be 0.999. The ratio of ethylene -α- olefin copolymer [A] an intrinsic viscosity [eta _A] of the intrinsic viscosity [eta _B] of the ethylene -α- olefin copolymer _{[B] ([η A]} /
[Η _B ]) is 1 or more, preferably 1.05 to 10 and more preferably 1.1 to 5 in combination.

Such an ethylene-α-olefin copolymer composition has a density of 0.890 to 0.955 g / cm 3.
³ , preferably in the range of 0.900 to 0.950 g / cm ³ , and the MFR in the range of 0.1 to 100 g / 10 minutes, preferably 0.2 to 50 g / 10 minutes.

This ethylene-α-olefin copolymer composition can be produced by a known method. For example, the ethylene-α-olefin copolymer [A] and the ethylene-α-olefin copolymer composition can be used. A method of mechanically blending the polymer [B] and optionally other components with an extruder, a kneader, or the like, or copolymerization of ethylene and α-olefin in two or more stages under different reaction conditions. Separately, a method of polymerizing the component corresponding to the above copolymer [A] and the component corresponding to the above copolymer [B] in the ranges of the above component ratios to obtain a copolymer composition, etc. are used. be able to.

Further, as the resin composition for the heat seal layer which is particularly preferably used in the present invention, ethylene comprising the above-mentioned ethylene-α-olefin copolymer [A] and ethylene-α-olefin copolymer [B]. A copolymer composition in which a low-density polyethylene obtained by high-pressure radical polymerization is further mixed with the -α-olefin copolymer can be mentioned. The low-density polyethylene obtained by the high-pressure radical polymerization blended with this copolymer composition is
A highly branched polyethylene having long chain branches produced by so-called high pressure radical polymerization,
MFR measured according to 238-65T at 190 ° C. under a load of 2.16 kg is 0.1 to 50 g / 10 minutes, preferably 0.2 to 10 g / 10 minutes, more preferably 0.1.
It is preferably in the range of 2 to 8 g / 10 minutes. In addition,
The high-pressure radical method low-density polyethylene used in the present invention is a copolymer with another α-olefin, vinyl acetate, a polymerizable monomer such as an acrylic ester, as long as the object of the present invention is not impaired. It may be.

In this composition, the ethylene-α-
The weight ratio of the total amount of the olefin copolymer [A] and the ethylene-α-olefin copolymer [B] to the high pressure radical polymerization low density polyethylene is 99: 1 to 5: 9.
5, preferably 90:10 to 60:40, particularly preferably 95: 5 to 75:25.

By blending the high-pressure polyethylene as described above, the MT of the composition can be increased, and as a result, there is an effect that the thickness of the heat-sealed portion is reduced and the heat-sealed strength is increased. Such an ethylene-based copolymer composition can be produced using a known method,
For example, a method of mechanically blending an ethylene-α-olefin copolymer composition, a high-pressure radical-polymerization low-density polyethylene, if necessary, and other components optionally added with an extruder, a kneader, or the like. Can be manufactured in.

The film for packaging a light-sensitive material of the present invention preferably has the following layer structure. Titanium white-free polyolefin layer (surface layer) / light-shielding film layer (intermediate layer) / heat seal layer, light-shielding film layer (surface layer) /
The total thickness of the heat seal layer and the light-shielding laminated film is usually 80 to 180 μm, preferably 100 to 160 μm,
More preferably, it is 120 to 140 μm. The thickness of the light-shielding film layer constituting the light-shielding laminated film is usually 40 to 80 μm, preferably 50 to 70 μm.
More preferably, it is 55 to 65 μm. The thickness of the titanium white-containing polyolefin layer is usually 10 to 10.
50 μm, preferably 20-40 μm, preferably
It is 25 to 35 μm.

The light-shielding laminated film is, as described above,
It is preferable that a part of the plurality of polyolefin-based film layers is composed of a diagonally oriented cross film formed by laminating a plurality of polyolefinic obliquely oriented films so that their molecular orientations intersect each other. Further, the crossing angle formed by a plurality of polyolefin-based obliquely oriented films in the longitudinal direction of the mutual molecular orientation axes is 30 to 150 degrees, preferably 60 to 120 degrees. The light-shielding film having such a diagonally oriented cross film as a constituent layer is particularly excellent in properties such as tear strength, falling weight impact strength and heat seal strength, and can prevent pinholes from occurring.

In addition, the longitudinal direction of the light-shielding laminated film (M
Ratio of tear strength in D) to tear strength in transverse direction (TD) (M
D / TD) is 0.4 or more, preferably 0.5 or more, and the tear strength in the machine direction (MD) and the transverse direction (TD) are both 50 g or more, preferably 60 g or more. The strength is 600 g or more, preferably 700 g or more.

The light-shielding laminated film of the present invention can be produced by a conventionally known method for laminating a plastic film. As such a laminating method, for example, (1) a method of extruding sandwich laminating two types of single or coextruded two-layer films to laminate. (2) A method of dry laminating two types of single or coextruded two-layer films to laminate them. (3) A method in which two types of single-piece or coextrusion two-layer films are heat-sealed and laminated. (4) Although there are processing methods such as a method of laminating two kinds of simple substance or coextruded two-layer film by hot melt, the method of the above (1) is generally the most commonly used method and has good quality stability. Most preferred.

Of the above laminating methods, the coextrusion laminating method is preferable in terms of cost. The obliquely oriented cross film described above is manufactured as follows. First,
The polyolefin-based obliquely oriented film, which is a raw material of the obliquely oriented cross film, can be produced by a conventionally known method. For example, a tubular film obtained by an inflation method is stretched in its axial direction, and then spirally cut (Japanese Patent Publication No. 40-5319), or a tubular film extruded by a circular die is stretched in the film-forming direction. While continuously rotating the mandrel and the binch roll to orient the tubular film in a twisted spiral shape, a method of making an incision in the film forming direction or folding without making an incision (Japanese Patent Publication No. 47-38621).
Japanese Laid-Open Patent Publication No. JP-A-2003-222, a tubular film extruded by a circular die is installed in two mandrels, a fixed mandrel and a rotating mandrel, and stretched and oriented in an oblique direction between both mandrels, and then drawn by a pinch roll and a pull roll. (Japanese Patent Publication No. 53-38306), and further, the circular die and the first mandrel are rotated, and the second mandrel of the pulling roll is rotated in the opposite direction so as to compensate the twist of the tubular film with respect to the pulling roll, There is a method of obtaining an obliquely oriented film by means of an apparatus (Japanese Patent Publication No. 54-15892) which enables molding without rotating the pulling roll and the winding roll. Among them, Japanese Patent Publication Sho 53-38
The method using the apparatus described in Japanese Patent Publication No. 306 and Japanese Patent Publication No. 54-15892 is preferable because it can be stretched and obliquely oriented at an arbitrary orientation ratio to obtain an appropriate strength.

The orientation ratio of the original film (stretched film tensile strength / unstretched film tensile strength) is appropriately determined depending on the application, but is usually 1.2 times or more, preferably 1.5 times or more.
It is preferable to use a raw film that has been stretched to about 5 times. Further, the direction of the orientation axis of the original film is also appropriately determined depending on the application, but usually, the crossing angle of the orientation axes when the original film is laminated by crossing the orientation axis is the length of the original film. It is good to set it in the range of 30 to 150 degrees, preferably 60 to 120 degrees in the direction.

Next, as a method of bonding the two obliquely oriented films, there are various conventionally known methods. For example, after applying a vinyl-based, acrylic-based, polyamide-based, epoxy-based, rubber-based, or urethane-based adhesive to one side of the original film, dry the adhesive and press the remaining one original film. Dry laminating method with heat bonding, corona treatment on one side of original film and / or anchor treatment with organotitanium type, polyethyleneimine type, isocyanate type, low density polyethylene (including high pressure method and medium and low pressure method), ethylene Examples include an extrusion laminating method in which a vinyl acetate copolymer or the like is extrusion laminated and pressure-laminated with the remaining one original film, or a hot melt laminating method.

In the packaging film of the present invention, a heat seal layer is laminated on the light-shielding film layer or the light-shielding laminated film on the light-shielding film layer side. The thickness of the heat-sealing layer to be laminated is usually 10 μm to 70 μm, preferably 20 μm.
μm to 40 μm. As the laminating method, a method known per se can be used. For example, the light-shielding film layer or the light-shielding laminated film and the heat-sealing layer can be formed by using thermocompression bonding, dry laminating method, hot melt laminating method, extrusion sandwich laminating method or the like. May be laminated simultaneously, or the heat seal layer may be laminated later.

In addition to the above, the packaging film of the present invention is, for example, a heat stabilizer, an ultraviolet absorber, a hydrochloric acid absorber, a lubricant, a slip agent, a pigment, a pigment dispersant, and a dye within the range that does not impair the object of the present invention. Various compounding agents such as an antistatic agent, an antifogging agent, an antiblocking agent and a filler can be added. Examples of the heat resistance stabilizer include various phenolic stabilizers, phosphorus-containing stabilizers, sulfur-containing stabilizers, nitrogen-containing stabilizers and the like. It is preferable to add 0.001 to 5 parts by weight of these heat stabilizers to 100 parts by weight of the polymer.

Examples of the ultraviolet absorber include benzotriazole compounds, benzophenone compounds, salicylate compounds and the like. The amount of these ultraviolet absorbers blended is preferably 0.001 to 5 parts by weight per 100 parts by weight of the polymer.

Examples of the lubricant include higher fatty acids such as lauric acid, oleic acid, stearic acid and metal salts thereof such as calcium salt, barium salt and zinc salt, higher fatty acid esters, polyolefin wax and other synthetic waxes, higher alcohols, Mention may be made of natural waxes. The lubricant is preferably blended in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the polymer.

Examples of the slip agent include amide wax. Specific examples thereof include methylenebis stearoamide, ethylenebissuaroamide, stearic acid amide, erucic acid amide, and oleic acid amide. The amount of the antistatic agent added to the polymer is preferably 0.01 to 5 parts by weight per 100 parts by weight of the polymer.

In the present invention, for example, even if a slip agent is mixed in a large amount in the light-shielding layer, for example, 1000 ppm or more, and the heat-sealing layer is not blended at all, the slip agent is actually transferred from the light-shielding layer to the heat-sealing layer. It was also found that a slip property of a degree that would not be a problem is obtained.

Examples of the antistatic agent include various anionic surfactants, cationic surfactants, amphoteric surfactants, betaine surfactants, nonionic surfactants and the like. The amount of the antistatic agent added to the polymer is preferably 0.01 to 5 parts by weight per 100 parts by weight of the polymer.

[0080]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The physical properties of the light-shielding films in Examples and Comparative Examples were evaluated by the following test methods. (1) Molecular orientation angle The molecular orientation angle was measured by notching the stretched film and measuring the angle of the splitting direction with a protractor. (2) Heat seal strength The heat seal strength was determined by performing a heat seal test according to JIS Z1707.

(3) Light-shielding property The light-shielding property is the light-emitting source (100 V, 100 W incandescent lamp, 2
The thick rubber packing (5 to 10 mm thick) is placed on the flange portion of the metal container having the flange portion in which the film sample (1.1 m width × 1.
(1 m length) was placed, and the film sample was further pressed from above by an air cylinder type jig capable of being completely fixed in four directions via rubber packing (5 to 10 m thickness). This jig has a frame member having a shape corresponding to the flange portion, and the frame member is connected to the piston rod of the air cylinder via an arm. Therefore, the jig is configured such that when the piston rod is lowered by the air cylinder, the film sample between the rubber packings can be pressed and pinched by the frame member and the flange portion.

The light-shielding property was measured and evaluated by setting the measurement chamber in a dark room, visually observing the film sample, and preparing five types of evaluation samples with different amounts of carbon black (CB) prepared in advance for the state of transmitted light. It collated with. The measurement effective sample width is 1 m × 1 m. Evaluation sample: C.I. B. Quantity, large ＋2 ・ ・ ・ Highly light-shielding property ↑ +1 ・ ・ ・ Highly light-shielding property 0 ・ ・ ・ While light-shielding property is recognized (reference sample) -1 ・ ・ ・ Lower light-shielding property ・ ・ ・ 2 ・ ・ ・ Highly light-shielding property Bad ↓ C. B. Amount and small In addition, the evaluation display method of the light-shielding property is as follows. ◯: Good light-shielding property (+2, 1) Δ: Light-shielding property intermediate between ◯ and × (0) ×: Poor light-shielding property (-1, -2)

(4) Measurement of Density After cutting the strand obtained by MFR measurement into about 5 mm,
After heating at 100 ° C. for 1 hour, the mixture is gradually cooled and then left at room temperature for 1 hour. After that, the density was measured with a density gradient tube. The resins shown in Table 1 below were used as the raw material resins for the respective layer films used in Examples and Comparative Examples. (5) Static friction coefficient and blocking property The friction coefficient was determined by conducting a friction coefficient test according to JIS-K-7125. For blocking, AST
The blocking test was performed according to MD-1893-67.

[0084]

[Table 1]

Example 1 As a raw material for forming the surface layer (first layer) of the light-shielding film, 50 parts by weight of high-density polyethylene (6) (described in Table 1), ethylene-1-hexene copolymer ( 5) Density 0.920 g / cm ³ , branching degree 17/1000 C (described in Table 1) 50 parts by weight and titanium white (Tokyo Ink Co., Ltd., trade name PZX680)
0 white) 2 parts by weight of the blend and 35 parts by weight of high-density polyethylene (6) and 65 parts by weight of ethylene-1-hexene copolymer (5) as raw materials for forming the light-shielding film intermediate layer (layer II). As a slip agent, a blend of 0.1 part by weight of oleic acid amide and 3 parts by weight of carbon black (trade name Black 40 manufactured by Tokyo Ink Co., Ltd.) was used, and each layer had a thickness of 30 μm and a film orientation angle of 45.
Degree film was molded. Next, each of the two types of films obtained as described above is arranged so that the orientation crossing angle is 90 degrees with each other, and the heat sealing layer (II
I layer) as an ethylene-1-hexene copolymer (1)
(Density 0.910 g / cm ³ , branching degree 17/1000
C) 100 parts by weight of oleic acid amide slip agent 0.0
A film having a thickness of 30 μm containing 5 parts by weight of the above layer (I
I) was placed on the layer side and this was extrusion sandwich laminated. The obtained obliquely oriented cloth laminated film has a thickness of 130.
μm. The physical properties of this laminated film are shown in Table 2.

Examples 2 to 4 In Example 1, as a raw material resin for the heat-sealing layer (third layer), the copolymers or copolymer compositions (copolymer (2),
A diagonally oriented cross-laminated film was prepared in the same manner as in Example 1 except that (3) the copolymer (1) and the high-pressure low-density polyethylene (6) (80:20 weight ratio blend) were used. It was made. Table 2 shows the physical properties and the like of these laminated films.

[Example 5] In Example 1, the amount of oleic acid amide in the light-shielding film intermediate layer (layer II) was 0.2 parts by weight, and the raw material resin for the heat-sealing layer (layer III) was 80: ethylene-4-methyl-1-pentene copolymer (1) and high-pressure low-density polyethylene (6):
A diagonally oriented cross-laminated film was prepared in the same manner as in Example 1, except that the weight ratio blend of 20 was used. Table 2 shows the physical properties of these laminated films.

[Comparative Examples 1 to 3] In Example 1, the copolymers (copolymers (4) and (5)) shown in Table 3 were used as raw material resins for the heat-sealing layer (third layer). Except for the above, the same treatment as in Example 1 was carried out to produce a diagonally oriented cross laminated film. Table 3 shows the physical properties and the like of these laminated films.

[Comparative Example 4] In Example 1, the amount of the oleic acid amide in the light-shielding film intermediate layer (layer II) was 0.2 parts by weight, and the raw material resin for the heat-sealing layer (layer III) was A diagonally oriented cross-laminated film was prepared in the same manner as in Example 1, except that the ethylene-4-methyl-1-pentene copolymer (5) was used. Table 3 shows the physical properties and the like of this laminated film.

[0090]

[Table 2]

[0091]

[Table 3]

[0092]

The film for packaging a light-sensitive material of the present invention has the above-mentioned specific layer structure, and in particular, the heat-sealing layer is mainly composed of a specific ethylene-α-olefin copolymer produced by using a metallocene catalyst. Because it consists of layers
Compared with other conventional heat-sealing resins as a packaging laminated film using a heat-sealing layer, the film surface has less stickiness, slip properties, excellent blocking properties, etc.,
Moreover, since heat sealing can be performed at a low temperature, shrinkage of the packaging film is avoided, and the appearance is excellent.

Further, it is polymerized with a metallocene catalyst and has a melt flow rate of 0.01 to 1.0 g / 10 minutes and a density of 0.89.
-0.92 g / cm ³ copolymer and melt flow rate 1.0-10 g / 10 min, density 0.91-0.94 g /
The two-step polymerized product or the extruder blend with the cm ³ copolymer has an excellent balance of slip property, heat seal property, heat seal strength and moldability.

Further, when a composition obtained by blending a small amount of high-pressure polyethylene with this copolymer is used as the heat-sealing layer resin, the melting property of the composition is improved and the molding of the sealing layer becomes easier. In addition, the seal layer is less sticky, the slipperiness is further improved, the thickness of the seal layer is not reduced when heat-sealed, and the heat-sealing strength of the film is also increased.

Also, no slip agent is added or 0.5 to 0.5.
% Or less, it is economically advantageous with excellent long-run workability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03C 3/00 565 G03C 3/00 565G

Claims (8)

[Claims] 1. A laminated film comprising a light-shielding layer (A) formed from a composition comprising an ethylene polymer and a light-shielding material and a heat-sealing layer (B), wherein the heat-sealing layer (B) is ASTM D1238-. 190 according to 65T
Melt flow rate MF at ℃, 2.16kg load
R is 0.1 to 10 g / 10 minutes, density is 0.88 to 0.93
A film for packaging a light-sensitive material, which is a layer containing as a main component a copolymer of ethylene and an α-olefin having 3 or more carbon atoms, which is produced using a g / cm ³ metallocene polymerization catalyst. 2. The film for packaging a photosensitive material according to claim 1, wherein the light shielding material is carbon black. 3. The ethylene-based polymer film, wherein the laminated film has a molecular orientation in a certain oblique direction.
From a diagonally oriented ethylene-based polymer laminated film and a heat-sealing layer, wherein the sheets are laminated so that their molecular orientations cross each other, and at least one of the at least two laminated films contains a light-shielding material. The film for packaging a photosensitive material according to claim 1 or 2, wherein 4. The carbon black is blended in a layer facing the heat seal layer of the obliquely oriented ethylene polymer laminated film, and the titanium oxide is blended in another layer. Film for packaging photosensitive materials. 5. The ethylene polymer has a melt flow rate (ASTM D1238, 190 ° C., 2.16 k).
g) 0.5 to 10 g / 10 minutes, density 0.90 to 0.93
5 g / cm ³ ethylene / α-olefin copolymer 10
~ 80 wt% and melt flow rate 0.01-0.5
A film for packaging a photosensitive material according to claim 1, which is a composition comprising 90 to 20% by weight of high-density polyethylene having a density of g / 10 minutes and a density of 0.94 to 0.97 g / cm ³ . 6. A gel permeation chromatography (G) of a copolymer forming a main component of the heat seal layer.
Mw / Mn measured by PC) is 1.5 to 7, GPC-
Letting Bh be the average degree of branching of the high molecular weight fraction and Bl be the degree of branching on the low molecular weight side measured using IR, the following formula (I) BR = Bh / Bl> 1 (I) The film for packaging a photosensitive material according to claim 1, which holds. 7. The peak of the heat of fusion curve obtained by a differential scanning calorimeter (DSC) of the copolymer forming the main component of the heat-sealing layer has two or more peaks. A film for packaging a light-sensitive material according to any one of claims 1 to 6. 8. The heat seal layer has a melt flow rate (MFR) of 0.1 to 10 g / 10 minutes and a density of 0.88 to.
95-5% by weight of a copolymer of ethylene and an α-olefin having 3 or more carbon atoms produced by using a metallocene polymerization catalyst of 0.93 g / cm ³ and low-density polyethylene produced by a high pressure method 5-95% by weight %, And a film for packaging a light-sensitive material according to any one of claims 1 to 7.