JP2005271420A - Film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film forming method for forming a film comprising an ethylene-α-olefine copolymer, and having less fish eye. <P>SOLUTION: This forming method is used for forming the film comprising the ethylene-α-olefine copolymer containing a constituent unit induced from ethylene, and a constituent unit induced from 4-20C α-olefine. A melt float rate (MFR; the unit is g/10 minutes) of the ethylene-α-olefine copolymer, and melting tension (MT; the unit is cN) at 190°C satisfy a relationship of an equation (1): 2×MFR<SP>-0.59</SP><MT<20×MFR<SP>-0.59</SP>. A limiting viscosity ([η]; the unit is dl/g) and the MFR satisfy a relationship of an equation (2): 1.02×MFR<SP>-0.094</SP><[η]<1.50×MFR<SP>-0.156</SP>. After melting and kneading the ethylene-α-olefine copolymer by an extruder, the ethylene-α-olefine copolymer is fed to a die through a sintered filter having a filtration diameter of 1 to 60 μm, and is extruded from the die to form the film made of the ethylene-α-olefine copolymer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a film comprising an ethylene-α-olefin copolymer.

Films made of an ethylene-based resin are excellent in physical properties such as transparency, strength, and heat sealability, and are therefore used in packaging, agricultural, standard bags, and the like. On the other hand, ethylene-based resins have a drawback that they tend to produce so-called fish eyes in the process of producing a film, and may not be used depending on the application.
In general, when producing films using ethylene-based resins such as high-pressure low-density polyethylene and ethylene-vinyl acetate copolymer, a sintered filter with a small filtration diameter is used as a method to suppress the generation of fish eyes. A method for producing a film is known. However, when a film is produced using an ethylene-α-olefin copolymer, if a sintered filter having a small filtration diameter is used, the passage resistance of the filter, that is, the pressure loss becomes extremely large, making it difficult to produce the film. It was often.
As a method for solving such a problem, a method for producing a film made of an ethylene-α-olefin copolymer using a gear pump and a sintered filter is known (see, for example, Patent Document 1).
JP-A-8-103952

However, when a gear pump is used, resin often stays in the gear pump and deteriorates.
The present invention provides a method for producing a film with less fisheye made of an ethylene-α-olefin copolymer without using a gear pump.

That is, the present invention is a method for producing a film comprising an ethylene-α-olefin copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 4 to 20 carbon atoms, The relationship between the melt flow rate (MFR; unit is g / 10 minutes) of the ethylene-α-olefin copolymer and the melt tension (MT; unit is cN) at 190 ° C. of the following formula (1) The intrinsic viscosity ([η]; the unit is dl / g) and the MFR satisfy the relationship of the following formula (2), and the ethylene-α-olefin copolymer is melt-kneaded in an extruder. Then, the film is supplied to a die through a sintered filter having a filtration diameter of 1 to 60 μm and extruded from the die, and is a method for producing a film made of an ethylene-α-olefin copolymer.
2 x MFR ^-0.59 <MT <20 x MFR ^-0.59 Formula (1)
1.02 × MFR ^−0.094 <[η] <1.50 × MFR ^−0.156 Formula (2)

According to the method for producing a film of the present invention, a film made of an ethylene-α-olefin copolymer with little fish eye can be produced without using a gear pump.

  The ethylene-α-olefin copolymer used in the present invention is an ethylene-α-olefin copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 4 to 20 carbon atoms. .

  The structural unit derived from ethylene is a unit derived from ethylene as a monomer and contained in the ethylene-α-olefin copolymer. The structural unit derived from an α-olefin having 4 to 20 carbon atoms is a unit derived from an α-olefin having 4 to 20 carbon atoms as a monomer and contained in an ethylene-α-olefin copolymer. is there. Examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and the like. More preferred are 4-methyl-1-pentene and 1-hexene.

  The α-olefin having 4 to 20 carbon atoms may be a combination of two or more, such as 1-butene and 4-methyl-1-pentene, 1-butene and 1-hexene, 1-butene and 1-butene. Examples include octene, 1-butene and 1-decene. More preferred are 1-butene and 4-methyl-1-pentene, 1-butene and 1-hexene.

  Content of the structural unit induced | guided | derived from ethylene is 50 to 99 weight% with respect to the total weight (100 weight%) of an ethylene-alpha-olefin copolymer. Content of the structural unit induced | guided | derived from a C4-C20 alpha olefin is 1-50 weight% with respect to the total weight (100 weight%) of an ethylene-alpha-olefin copolymer.

  The ethylene-α-olefin copolymer used in the present invention, in addition to the structural unit derived from ethylene and the structural unit derived from an α-olefin having 4 to 20 carbon atoms, has ethylene and 4 to 20 carbon atoms. A small amount of structural units derived from other monomers than α-olefin may be contained. Examples of other monomers include conjugated dienes (for example, butadiene and isoprene), non-conjugated dienes (for example, 1,4-pentadiene), acrylic acid, acrylic acid esters (for example, methyl acrylate and ethyl acrylate), and methacrylic acid. , Methacrylate esters (for example, methyl methacrylate and ethyl methacrylate), vinyl acetate and the like.

  In the present invention, since a film having excellent strength is obtained, a copolymer of ethylene and an α-olefin having 5 to 10 carbon atoms, or ethylene, 1-butene and an α-olefin having 5 to 10 carbon atoms It is preferable to use a copolymer of ethylene, and it is more preferable to use a copolymer of ethylene and an α-olefin having 6 to 10 carbon atoms.

The ethylene-α-olefin copolymer used in the present invention has a melt flow rate (MFR; the unit is g / 10 minutes) and a melt tension (MT; the unit is cN) at 190 ° C. It satisfies the relationship (1).
2 x MFR ^-0.59 <MT <20 x MFR ^-0.59 Formula (1)

Conventional ethylene-α-olefin copolymers are known to have an increased MFR and an increase in fluidity, that is, a decrease in melt viscosity and a decrease in melt tension. Since the ethylene-α-olefin copolymer used in the present invention has a smaller proportion of decrease in melt tension with an increase in MFR than the conventional ethylene-α-olefin copolymer, the relationship of the above formula (1) The ethylene-α-olefin copolymer is excellent in extrusion processability. When MT is 2 × MFR ^−0.59 or less, bubble stability in inflation processing may deteriorate, or neck-in may occur in T-die processing. When MT is 20 × MFR ^−0.59 or more May be difficult to take up at high speed.

In the ethylene-α-olefin copolymer used in the present invention, the relationship between MT and MFR is 2.2 × MFR ^−0.59 <MT <15 × MFR ^−0.59.
It is preferable that
2.5 × MFR ^-0.59 <MT <10 × MFR ^-0.59
It is.

  The melt flow rate (MFR; unit is g / 10 minutes) in the above formula (1) is a load of 21.18 N (2.16 Kg) at 190 ° C. according to the method defined in JIS K7210-1995. It is the value measured by.

  The melt tension (MT; unit is cN) in the above formula (1) is 190 ° C., extrusion speed 5.5 mm / min using a melt tension tester sold by Toyo Seiki Seisakusho, etc. When the molten resin strand is extruded from an orifice having a diameter of 2.09 mmφ and a length of 8 mm, and the strand is wound using a roller having a diameter of 50 mm while increasing the rotational speed by 40 rpm per minute, The tension value just before the strand breaks.

In the ethylene-α-olefin copolymer used in the present invention, the intrinsic viscosity ([η]; the unit is dl / g) and the MFR satisfy the relationship of the following formula (2).
1.02 × MFR ^−0.094 <[η] <1.50 × MFR ^−0.156 Formula (2)

In general, it is known that ethylene-α-olefin copolymers have an increase in MFR and an increase in fluidity, that is, a decrease in melt viscosity and a decrease in intrinsic viscosity. The ethylene-α-olefin copolymer used in the present invention has a smaller ratio of decrease in intrinsic viscosity with increasing MFR than the conventional ethylene-α-olefin copolymer. The ethylene-α-olefin copolymer is excellent in extrusion processability. When [η] is 1.02 × MFR ^−0.094 or less, bubble stability in inflation processing may deteriorate, or neck-in may occur in T-die processing, and [η] is 1.50 ×. When MFR is ^-0.156 or more, the load on the extruder becomes high, and it may be difficult to continuously produce the film for a long time, or the surface of the resulting film may be rough.

In the ethylene-α-olefin copolymer used in the present invention, the relationship between [η] and MFR is 1.05 × MFR ^−0.094 <[η] <1.47 × MFR ^−0.156.
It is preferable that
1.08 × MFR ^−0.094 <[η] <1.42 × MFR ^−0.156
It is.

The intrinsic viscosity ([η]; unit is dl / g) in the above formula (2) is a value measured by the following method. A sample solution is prepared by dissolving 100 mg of an ethylene-α-olefin copolymer at 135 ° C. in 100 ml of tetralin containing 5% by weight of butylhydroxytoluene (BHT) as a thermal degradation inhibitor. The falling time of the sample solution and the blank solution was measured using an Ubbelohde viscometer, and after obtaining the relative viscosity (ηrel) at 135 ° C. from these values, the relative viscosity (ηrel) was used to calculate It is calculated. The blank solution is tetralin containing only 5% by weight of BHT.
[Η] = 23.3 × log (ηrel)

The ethylene-α-olefin copolymer used in the present invention is a log normal distribution curve obtained by dividing a chain length distribution curve obtained by gel permeation chromatography measurement into at least two log normal distribution curves. It is preferable that the chain length A (unit Å) at the peak position of the logarithmic normal distribution curve corresponding to the component having the highest molecular weight and the MFR satisfy the relationship of the following formula (3). Such an ethylene-α-olefin copolymer is more excellent in extrusion moldability.
3.30 <logA <−0.0815 × log (MFR) +4.05 Formula (3)

In the ethylene-α-olefin copolymer used in the present invention, the relationship between the chain length A and MFR is 3.30 <logA <−0.0815 × log (MFR) +4.03.
It is more preferable to satisfy, more preferably
3.30 <logA <−0.0815 × log (MFR) +4.02
It is.

The chain length distribution curve is obtained by gel permeation chromatography measurement under the following conditions.
(1) Apparatus: Waters 150C manufactured by Water
(2) Separation column: TOSOH TSKgelGMH-HT
(3) Measurement temperature: 145 ° C
(4) Carrier: orthodichlorobenzene (5) Flow rate: 1.0 mL / min (6) Injection volume: 500 μL

The chain length distribution curve is divided as follows.
First, a chain length distribution curve in which a weight ratio dW / d (logAw) (y value) is plotted against logAw (x value) that is the logarithm of chain length Aw is measured by gel permeation chromatography measurement. The number of plot data is usually at least 300 or more so as to form a continuous distribution curve. Next, four lognormal distribution curves (xy) having a standard deviation of 0.30 and an arbitrary average value (usually corresponding to the chain length A of the peak position) with respect to the above x value. Curve) is added at an arbitrary ratio to create a composite curve. Further, the average value and the ratio are obtained so that the deviation sum of squares of the y value with respect to the same x value of the actually measured chain length distribution curve and the combined curve becomes a minimum value. The minimum value of the deviation sum of squares is usually 0.5% or less with respect to the deviation sum of squares when the ratios of the peaks are all zero. The logarithm corresponding to the component having the highest molecular weight among the lognormal distribution curves obtained by dividing the logarithmic normal distribution curve into four lognormal distribution curves when the average value and the ratio giving the minimum value of the deviation sum of squares are obtained. Log A is calculated from the chain length A at the peak position of the normal distribution curve. The ratio of the peak of the lognormal distribution curve corresponding to the highest molecular weight component is usually 10% or more.

The ethylene-α-olefin copolymer used in the present invention has a characteristic relaxation time (τ; unit is sec) at 190 ° C. and MFR represented by the following formula (4) from the viewpoint of the appearance of the obtained film. It is preferable to satisfy.
2 <τ <8.1 × MFR− ^0.746 formula (4)

In the ethylene-α-olefin copolymer used in the present invention, τ and MFR are 2 <τ <7.9 × MFR− ^0.746.
It is more preferable to satisfy
2 <τ <7.8 × MFR ^−0.746
It is.

  The characteristic relaxation time (τ) at 190 ° C. is dynamic viscoelasticity data at each temperature T (K) measured under the following conditions using Rheometrics Mechanical Spectrometer RMS-800 manufactured by Rheometrics as a viscoelasticity measuring device. Is shifted based on the temperature-time superposition principle, and the dynamic viscosity (η; unit is Pa · sec) at 190 ° C. depends on the shear rate (ω: unit is rad / sec). Is a numerical value calculated when the master curve is approximated by the following cross equation after obtaining the master curve.

The measurement conditions of dynamic viscoelasticity data at each temperature T (K) are as follows.
(1) Geometry: Parallel plate, diameter 25 mm, plate interval: 1.5-2 mm
(2) Strain: 5%
(3) Shear rate: 0.1 to 100 rad / sec
(4) Temperature: 190, 170, 150, 130 ° C
As a sample for measuring dynamic viscoelasticity, a sample in which an appropriate amount (for example, 1000 to 10,000 ppm) of an antioxidant such as Irganox 1076 is blended in advance is used, and all measurements are performed under nitrogen.

Cloth's approximate equation η = η0 / [1+ (τ × ω) ⁿ ]
(Η0 and n are constants determined for each ethylene-α-olefin copolymer used in the measurement, similarly to the characteristic relaxation time τ.)
In addition, Rheometrics Rhios V. is used as a calculation software for creating a master curve and cross-type approximation. Use 4.4.4.

  The melt flow rate (MFR) of the ethylene-α-olefin copolymer used in the present invention is usually 0.1 to 100 g / 10 minutes, preferably 0.5 to 50 g / 10 minutes, more preferably. 1 to 20 g / 10 minutes, more preferably 2 to 15 g / 10 minutes.

  The ethylene-α-olefin copolymer used in the present invention preferably has a molecular weight distribution of 0.5 to 25, more preferably 1 to 20, more preferably 1.5 to 10 from the viewpoint of extrusion processability. It is. The above-mentioned molecular weight distribution is a polystyrene equivalent weight average molecular weight (Mw) and number average molecular weight (Mn) calculated for the chain length distribution obtained by the gel permeation chromatography measurement, and Mw is divided by Mn. Value (Mw / Mn).

The density of the ethylene-α-olefin copolymer used in the present invention is usually 890 to 970 kg / m ³ . The density is measured according to JIS K6760-1981.

  The above melting point is a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, and 8 to 12 mg of sample is packed in an aluminum pan and held at 150 ° C. for 2 minutes, and then up to 40 ° C. at 5 ° C./min. The melting peak temperature observed when the temperature is lowered and held at 40 ° C. for 2 minutes and then raised to 150 ° C. at 5 ° C./min. Among them, the temperature at the highest melting peak position is defined as the maximum melting point Tmax.

  From the viewpoint of fluidity, the ethylene-α-olefin copolymer used in the present invention preferably has a flow activation energy (Ea; the unit is kJ / mol) larger than 40 kJ / mol, more preferably. It is 45 kJ / mol or more, more preferably 50 kJ / mol or more.

The activation energy (Ea) of flow is the temperature T measured under the same conditions as when the characteristic relaxation time (τ) is calculated using Rheometrics Mechanical Spectrometer RMS-800 manufactured by Rheometrics as a viscoelasticity measuring device. The dynamic viscoelasticity data is shifted based on the temperature-time conversion rule, and the dependence of the dynamic viscosity (η; unit is Pa · s) at 190 ° C. on the angular frequency (ω: unit is rad / s) is shown. This is a numerical value calculated from the Arrhenius equation of the shift factor (a _T ) when creating the master curve.

An Arrhenius equation of the shift factor (a _T ) is shown in Equation (1).
log (a _T ) = Ea / R (1 / T−1 / T ₀ ) (1)
(R is a gas constant and T ₀ is a reference temperature (463 K).)
The activation energy calculation software includes Rheometrics Rhios V. 4.4.4 was used. In the Arrhenius type plot log (a _T ) − (1 / T), the Ea value obtained by linear approximation by the least square method was defined as the activation energy of flow.

  The ethylene-α-olefin copolymer used in the present invention preferably has a melt flow rate ratio (MFRR) of 60 or more from the viewpoint of fluidity.

  The melt flow rate ratio (MFRR) is a value obtained by measuring a melt flow rate value measured at 190 ° C. under a load of 211.82 N (21.60 kg) according to a method defined in JIS K7210-1995 with a load of 21.18 N (2 .16 kg) divided by the melt flow rate value. For the measurement of the melt flow rate, a polymer containing 1000 ppm of an antioxidant in advance is used.

The method for producing the ethylene-α-olefin copolymer used in the present invention is not particularly limited. For example, the following metallocene olefin polymerization catalyst is used to copolymerize ethylene and α-olefin under hydrogen conditions. Obtained by polymerization.
The metallocene olefin polymerization catalyst is a catalyst obtained by bringing the promoter support (A), the crosslinked bisindenyl zirconium complex (B) and the organoaluminum compound (C) into contact with each other, and the promoter support (A) A support obtained by contacting diethylzinc (a), fluorinated phenol (b), water (c), silica (d) and (e) trimethyldisilazane (((CH ₃ ) ₃ Si) ₂ NH). .

The amount of each compound (a), (b), (c) used is not particularly limited, but the molar ratio of the amount of each compound used is (a) :( b) :( c) = 1: y: z It is preferable that y and z substantially satisfy the following formula (3).
| 2-y-2z | ≦ 1 (3)
In the above formula (3), y is preferably a number of 0.01 to 1.99, more preferably a number of 0.10 to 1.80, and still more preferably a number of 0.20 to 1.50. Yes, most preferably a number from 0.30 to 1.00.

  The amount of (d) used for (a) is the amount of zinc atoms derived from (a) contained in the particles obtained by contact between (a) and (d) in 1 g of the obtained particles. The amount of zinc atoms contained is preferably an amount of 0.1 mmol or more, more preferably 0.5 to 20 mmol, and it may be appropriately determined so as to be in this range. The amount of (e) used relative to (d) is preferably (e) 0.1 mmol or more per 1 g of (d), more preferably 0.5 to 20 mmol. preferable.

The cross-linked bisindenyl zirconium complex (B) is preferably racemic-ethylenebis (1-indenyl) zirconium dichloride or racemic-ethylenebis (1-indenyl) zirconium diphenoxide.
The organoaluminum compound (C) is preferably triisobutylaluminum or trinormaloctylaluminum.

The amount of the bridged bisindenyl zirconium complex (B) used is preferably 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ mol with respect to 1 g of the promoter support (A). The amount of the organoaluminum compound (C) used is preferably the ratio of the number of moles of aluminum atoms in the organoaluminum compound (C) to the number of moles of zirconium atoms in the crosslinked bisindenylzirconium complex (B) (Al / Zr). And 1 to 2000.

The polymerization method is preferably a polymerization method involving the formation of ethylene-α-olefin copolymer particles, such as gas phase polymerization, slurry polymerization, and bulk polymerization, and preferably gas phase polymerization.
The gas phase polymerization reaction apparatus is usually an apparatus having a fluidized bed type reaction tank, and preferably an apparatus having a fluidized bed type reaction tank having an enlarged portion. A stirring blade may be installed in the reaction vessel.

As a method for supplying each component of the metallocene-based olefin polymerization catalyst used in the production of the ethylene-α-olefin copolymer used in the present invention to the reaction vessel, usually, inert gas such as nitrogen and argon, hydrogen, ethylene Or the like, and a method in which the components are supplied without water, or a method in which each component is dissolved or diluted in a solvent and supplied in a solution or slurry state. Each component of the catalyst may be supplied individually, or arbitrary components may be supplied in contact in advance in an arbitrary order.
Moreover, it is preferable to carry out prepolymerization before carrying out the main polymerization and to use the prepolymerized catalyst component that has been prepolymerized as a catalyst component or catalyst for the main polymerization.

The polymerization temperature is usually below the temperature at which the copolymer melts, preferably 0 to 150 ° C, more preferably 30 to 100 ° C.
Further, hydrogen may be added as a molecular weight regulator for the purpose of regulating the melt fluidity of the copolymer. An inert gas may coexist in the mixed gas.

In the present invention, the ethylene-α-olefin copolymer obtained as described above is melt-kneaded with an extruder, and then supplied to a die through a sintered filter having a filtration diameter of 1 to 60 (μm). This is a method for producing a film made of an ethylene-α-olefin copolymer by extrusion from a die. By manufacturing a film by such a method, a film with few fish eyes can be continuously produced. As the extruder or die used in the present invention, an apparatus used in ordinary film forming can be used. Examples of the extruder include a single screw extruder and a twin screw extruder, and examples of the die include a T die and a circular die. From the viewpoint of productivity, the T die casting method is preferable.
There is no particular limitation on the temperature at which the ethylene-α-olefin copolymer is melt-kneaded and the temperature at which the ethylene-α-olefin copolymer is extruded from the die, but in the case of a circular die (inflation molding), it is usually 120 to 200 ° C. In order to suppress more, it is preferable that it is 120-160 degreeC. In the case of a T-die, the temperature is usually 170 to 260 ° C., and in order to further suppress the generation of fish eyes, the temperature is preferably 170 to 220 ° C.

The sintered filter used in the present invention is obtained by sintering a fibrous metal (generally made of stainless steel) and processing it into a mat shape, and known ones can be applied.
The filtration diameter of the sintered filter used in the present invention is in the range of 1 to 60 μm, preferably 5 to 50 (μm), more preferably 10 to 40 (μm).
The filtration diameter of the present invention is a contaminant particle diameter with a collection efficiency of 95% that passes through the sintered filter by the method of JIS-B8356.
If the filtration diameter is too small, the load on the extruder tends to be excessive at the time of film formation, and if the filtration diameter is too large, the filtration effect is insufficient and it tends to be difficult to suppress fish eyes.
Said sintered filter can be installed in the arbitrary site | parts between the extruder and die | dye of a film processing apparatus. In general, a method of fitting into a part (breaker plate) to which a metal mesh is attached is simple, but it is preferable to install using a special casing (for example, a known leaf disk filter).

  If necessary, the ethylene-α-olefin copolymer used in the present invention may be blended with other ethylene-based resins and may contain known additives. Examples of the additives include antioxidants, weathering agents, lubricants, antiblocking agents, antistatic agents, antifogging agents, dripping agents, pigments, fillers, and the like.

Next, the present invention will be described by examples.
[1] Evaluation method (0) MFR (In addition, the measurement methods and measurement results of physical properties described in the specification are also described in Examples) According to the method defined in JIS K7210-1995, at 190 ° C., a load of 21.18 N It was measured under the condition of (2.16 Kg).
(1) Electric motor load The electric current value (A: ampere) of the motor for driving the extruder screw was read. The lower this value, the lower the extrusion load, which is preferable.
(2) Resin pressure It read from the resin pressure gauge installed in the front-end | tip of an extruder. A smaller value indicates a smaller extrusion load and is preferable.

Example 1
[Preparation of catalyst components]
(1) Silica treatment Silica heated at 300 ° C. under nitrogen flow in a nitrogen-substituted 3 liter four-necked flask (Sypolol 948 manufactured by Devison; average particle size = 61 μm; pore volume = 1.70 ml / g) Specific surface area = 291 m ² / g) 0.2 kg was added, and then 1.2 liters of toluene was added while washing the silica adhering to the wall of the flask. After cooling to 5 ° C., a mixed solution of 1,1,1,3,3,3-hexamethyldisilazane 84.4 ml (0.4 mmol) and toluene 115 ml was added dropwise over 25 minutes. After completion of dropping, the mixture was stirred at 5 ° C. for 1 hour and then at 95 ° C. for 3 hours and filtered. Thereafter, the filter was washed four times with 1.2 liters of toluene at 95 ° C. Then, after adding 1.2 liters of toluene, it was left still overnight.

(2) Synthesis of cocatalyst carrier (A) 0.550 liter (1.10 mol) of diethylzinc in hexane (2.00 mol / liter) was added to the slurry obtained above and cooled to 5 ° C. A solution prepared by dissolving 105 g (0.570 mol) of pentafluorophenol in 173 ml of toluene was added dropwise thereto over 65 minutes. After completion of dropping, the mixture was stirred at 5 ° C. for 1 hour. Then, it heated at 40 degreeC and stirred for 1 hour. After the 5 ° C. in an ice bath _and H 2 O 14.9 g of (0.828mol) was added dropwise for 90 minutes. After completion of dropping, the mixture was stirred at 5 ° C. for 1.5 hours and at 40 ° C. for 2 hours. Then, it left still overnight at room temperature. Then, after stirring at 80 ° C. for 2 hours, the mixture is allowed to stand to settle the solid component, and when the interface between the precipitated solid component layer and the upper slurry portion is seen, the upper slurry portion is removed, and then the remaining liquid After filtering the components with a filter, 1.7 liters of toluene was added and stirred at 95 ° C. for 2 hours. Thereafter, the mixture was stirred 4 times with 1.7 liters of toluene at 95 ° C. and 2 times with 1.7 liters of hexane at room temperature, and then allowed to stand to precipitate the solid component. When the interface with the slurry portion was seen, the upper slurry portion was removed, and then the remaining liquid component was filtered through a filter. Thereafter, the solid component was dried at room temperature under reduced pressure for 3 hours to obtain 0.39 kg of a promoter support (A).
[Preparation of prepolymerization catalyst]
80 liters of butane containing triisobutylaluminum at a concentration of 2.5 mmol / liter, 4 liters of 1-butene 0.2 kg, hydrogen at normal temperature and normal pressure were charged in an autoclave with a stirrer having an internal volume of 210 liters that had been purged with nitrogen Thereafter, the temperature of the autoclave was raised to 20 ° C. Further, ethylene was charged by 0.1 MPa as the gas phase pressure in the autoclave, and after the system was stabilized, 0.2 mol of triisobutylaluminum, 0.1 mol of racemic-ethylenebis (1-indenyl) zirconium diphenoxide, Polymerization was started by adding 0.7 kg of the promoter support (A). While raising the temperature to 30 ° C. and continuously supplying ethylene and hydrogen, preliminary polymerization was carried out at 30 ° C. for a total of 2 hours. After the polymerization was completed, ethylene, butane, hydrogen gas and the like were purged, and the remaining solid was vacuum-dried at room temperature, so that 13 g of ethylene / 1-butene copolymer was prepolymerized per 1 g of the promoter support (A). A prepolymerized catalyst component was obtained.

[Polymerization] (GPE1842)
Using the prepolymerized catalyst component obtained above, ethylene and 1-hexene were copolymerized in a continuous fluidized bed gas phase polymerization apparatus. The polymerization conditions were a temperature of 75 ° C., a total pressure of 2 MPa, a hydrogen molar ratio to ethylene of 1.55%, and a 1-hexene molar ratio to ethylene of 1.0%, ethylene to maintain a constant gas composition during the polymerization, 1-hexene and hydrogen were continuously supplied. Ethylene / 1-hexene copolymerization with an average polymerization time of 4 hr and a production efficiency of 23 kg / hr so that the prepolymerized catalyst component and triisobutylaluminum are continuously supplied and the total powder weight of the fluidized bed is maintained at 80 kg. I got a powder.

[Kneading]
The ethylene / 1-hexene copolymer powder obtained above was blended with 1000 ppm of calcium stearate and 1800 ppm of Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd.) using an LCM100 extruder manufactured by Kobe Steel, Ltd., at a feed rate of 350 kg / An ethylene / 1-hexene copolymer was obtained by granulation under the conditions of hr, screw rotation speed 450 rpm, gate opening 0 mm, suction pressure 0.2 MPa, and resin temperature 200 to 230 ° C.

  Table 1 shows the physical properties of the ethylene / 1-hexene copolymer obtained. The MFR was 2.18.

[Film production]
The obtained ethylene / 1-hexene copolymer was produced with a T-die film molding machine manufactured by SHI Modern Machinery Co., Ltd.

The film was manufactured as follows. A sintered filter (MFF manufactured by Nippon Seisen Co., Ltd.) is placed on the breaker plate (φ51 mm) of the extruder having a diameter of 50 mm and L / D of 32 (L is the length of the cylinder of the extruder, D is the diameter of the cylinder of the extruder). NF06, filtration diameter: 10 μm) was set in a configuration sandwiched between 80 mesh wire nets. After melt-kneading the ethylene / 1-hexene copolymer at 300 ° C., it is supplied to a T die (600 mm width) adjusted to 300 ° C. through the sintered filter, extruded from the T die, and then 20 ° C. chill roll And then solidified by cooling to obtain a film having a thickness of 40 μm. At this time, the lip opening of the T die was set to 0.9 mm. In this way, production was carried out continuously for 4 hours.
During this production, the indicated value of the resin pressure gauge attached to the tip of the extruder (between the screw and the filter) was read.
The resulting film, only three per 1m ² there was no fish eye.

Comparative Example 1
Production was performed in the same manner as in Example 1 except that ethylene / 1-hexene copolymer (manufactured by Sumitomo Chemical Co., Ltd., FV402, MFR = 3.63) was used as a raw material.
With this raw material, since the resin pressure was high and the operation allowable limit of the apparatus exceeded 35 MPa, a film could not be produced.

※樹脂圧力が装置の制限（35ＭＰａ）を越えて加工不可

* Cannot be processed because the resin pressure exceeds the equipment limit (35MPa).

Claims (1)

A process for producing a film comprising an ethylene-α-olefin copolymer comprising a structural unit derived from ethylene and a structural unit derived from an α-olefin having 4 to 20 carbon atoms, the ethylene-α-olefin The melt flow rate (MFR; unit is g / 10 minutes) of the copolymer and the melt tension (MT; unit is cN) at 190 ° C. satisfy the relationship of the following formula (1), and the intrinsic viscosity: ([Η]; the unit is dl / g) and the MFR satisfy the relationship of the following formula (2), and after melt-kneading the ethylene-α-olefin copolymer with an extruder, the filtration diameter A method for producing a film comprising an ethylene-α-olefin copolymer, which is supplied to a die through a sintered filter of 1 to 60 μm and extruded from the die.
2 x MFR ^-0.59 <MT <20 x MFR ^-0.59 Formula (1)
1.02 × MFR ^−0.094 <[η] <1.50 × MFR ^−0.156 Formula (2)