JP2007331114A - Airing frame and manufacturing method of inflation film using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airing frame used in the molding of an inflation film comprising a thermoplastic resin and capable of manufacturing the inflation film excellent in transparency while keeping the stability of a tubular film in a molten state, and a manufacturing method of the inflation film using it. <P>SOLUTION: The airing frame is used for obtaining the tubular film by melting and kneading the thermoplastic resin in an extruder to extrude the molten thermoplastic resin from an annular die and equipped with an airing main body, a blowoff ring for blowing a cooling medium against the tubular film and a chamber ring for adjusting the flow of the blown cooling medium. The chamber ring is equipped with guide blades arranged so as to allow the cooling medium to spirally flow along the outer surface of the tubular film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air ring device used for forming an inflation film made of a thermoplastic resin, and a method for producing an inflation film using the air ring device.

Inflation films made of thermoplastic resins are used in a wide range of fields such as packaging, agriculture, and standard bags. In inflation molding, since it is necessary to cool the molten tubular film extruded from the annular die, an apparatus in which an air ring device for spraying a cooling medium is provided at the outlet of the annular die is used. In order to increase the film production speed, it is necessary to increase the cooling effect by increasing the speed of the cooling medium blown out from the air ring device. There was a problem that the tubular film in the state became unstable and high-speed processing became difficult.
As an air ring device for solving such a problem, two air outlets are provided as described in Patent Document 1, and one of the air outlets is perpendicular to the center line of the device. Devices are known in which the other outlet is oriented at a constant angle with respect to the same center line. By using such a device, the molten tubular film is quenched and stabilized by the cooling medium blown out from the blowout port oriented in the direction perpendicular to the center of the device, so that the other blowout port can be stabilized. The speed of the cooling medium to be supplied can be increased.
However, when an ethylene-α-olefin copolymer is blown using such an apparatus, the resulting film may be inferior in transparency.
JP-A-5-228993

The present invention is an air ring device used for forming a blown film of a thermoplastic resin, and an air ring device capable of producing a film having excellent transparency while maintaining the stability of a tubular film in a molten state, And the manufacturing method of the inflation film using this apparatus is provided.

  That is, the present invention relates to an air ring device used in inflation molding in which a thermoplastic resin is melt-kneaded with an extruder and extruded from an annular die to obtain a tubular film, and is cooled to the air ring main body and the tubular film. In an air ring apparatus including a blow ring for blowing a medium and a chamber ring for adjusting a flow of the blown cooling medium, the chamber ring includes guide vanes arranged so that the cooling medium flows spirally on the outer surface of the tubular film. The present invention relates to an air ring device including the air ring device, and an inflation film manufacturing method using the air ring device.

  By performing inflation molding using the air ring device of the present invention, it is possible to produce a film having excellent transparency while maintaining the stability of the molten tubular film. Moreover, according to the manufacturing method of the inflation film of this invention, the film which is excellent in transparency can be manufactured, maintaining the stability of the tube-shaped film of a molten state.

An air ring device used in inflation molding includes an air ring body that rectifies a cooling medium supplied from a blower, a blow ring that blows the cooling medium onto a molten tubular film extruded from an annular die, and a bubble. It consists of a chamber ring that produces a negative pressure effect and stabilizes the bubble. The chamber ring is a cylindrical member provided on the blowing ring with the center line of the annular die as the center, and a plurality of chamber rings are usually provided concentrically.
The air ring device of the present invention has a chamber ring provided with guide vanes arranged on the outer surface of the tubular film so that the cooling medium flows spirally. Specific examples of the guide vanes arranged so that the cooling medium spirally flows on the outer surface of the tubular film include the following examples.
(I) When a plurality of guide vanes are provided in one chamber ring, for example, as shown in FIG. 3, the chamber ring is cut by cutting one place on the circumference of the chamber ring perpendicularly to the annular die discharge surface. In the plan developed on the plane, the angle (α) formed by each guide vane and the annular die discharge surface is arranged on the inner surface of the chamber ring so that 0 ° <α <90 ° is satisfied. The angle (α) is preferably 5 to 85 °. The guide blades are preferably arranged at equal intervals.
(II) In the case where one guide blade is provided in one chamber ring, the chamber ring is developed on a plane by cutting one place on the circumference of the chamber ring perpendicularly to the annular die discharge surface. The angle (α) formed between the guide vane and the annular die discharge surface is arranged on the inner surface of the chamber ring so as to satisfy 0 ° <α <90 °. The angle (α) is preferably 5 to 85 °.

  The chamber ring is usually provided in a concentric shape centering on the center point of the annular die so that the height increases from the inside toward the outside. The guide vanes are preferably provided in all the chamber rings. When the chamber rings are provided in a plurality of stages, and the guide blades are arranged in two or more stages, the angle formed between the guide blades arranged on the inner chamber ring and the annular die discharge surface is set to the outer side. It is preferable that the angle is larger than the angle formed by the guide vanes arranged in the chamber ring and the annular die discharge surface.

The material, shape, number, etc. of the guide vanes are not particularly limited, but the material is preferably an aluminum alloy. The thickness of the guide blade is preferably 0.1 to 5 mm. The arrangement shape of the guide vanes may be flat or any curved surface. Moreover, the length per guide blade is usually 5 to 300 mm, preferably 10 to 200 mm.
The number of guide blades is not particularly limited, but is generally 4 to 100, and preferably 8 to 50, as a whole. Although the height from the chamber ring surface of a guide blade can be arbitrarily set according to the space of an arrangement | positioning location, it is 5-100 mm normally.

  In the conventional air ring device in which the guide vanes are not arranged on the chamber ring, the cooling medium is sprayed in the central axis direction of the tubular film and flows in the same direction as the traveling direction (extrusion direction) of the tubular film. To do. That is, the flow direction of the cooling medium is limited to a plane including the central axis of the tubular film. In such a case, if the flow rate of the cooling medium is increased, the tubular film is pushed and deformed by the cooling medium, so that it is difficult to stably perform the inflation molding. When an air ring device having a chamber ring having guide vanes as in the present invention is used, the cooling medium flows in the traveling direction of the tubular film while surrounding the outer surface of the tubular film in a spiral shape. Thereby, the flow rate of the cooling medium can be increased without impairing the stability of the tubular film, and as a result, the transparency of the resulting film can be improved.

  The cooling medium supplied to the air ring device of the present invention is usually air fed by a blower. The air can be directly taken into the blower indoors or outdoors, but it is preferable to apply a chiller that cools the air. The chiller is generally disposed between a blower and an air ring device, and cools a cooling medium supplied from the blower to the air ring device. When using a chiller, it is preferable that the temperature of the cooling medium supplied to an air ring apparatus shall be 5-20 degreeC.

  The air ring device of the present invention as described above is used as a cooling device when a thermoplastic resin is subjected to inflation molding. In a method for producing an inflation film, in which a thermoplastic resin is melt-kneaded with an extruder and extruded from an annular die, a tubular film extruded from the annular die is used as a cooling medium by using the air ring device. Can be cooled so that the cooling medium flows spirally on the outer surface of the tubular film. A known apparatus can be used as the extruder.

The thermoplastic resin used when the thermoplastic resin is formed into an inflation film using the air ring device of the present invention is not particularly limited, and is not limited to polyolefin resin, polystyrene resin, nylon resin, polyester resin, polymethyl methacrylate. Examples thereof include a rate, polyvinyl alcohol, polycarbonate, polyvinyl chloride, and polyvinylidene chloride. Of these, polyolefin resin is preferable because of easy inflation molding, and ethylene resin is more preferable.
The ethylene-based resin in the present invention means a thermoplastic ethylene polymer having a polyethylene crystal structure, which is a thermoplastic ethylene polymer containing 50% by weight or more of a structural unit derived from ethylene, A polymer, a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, or a copolymer of ethylene and at least one other monomer. Examples of the α-olefin include propylene, butene-1, 4-methylpentene-1, hexene-1, octene-1, and decene-1. Examples of the 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), methacrylic acid, and methacrylic acid esters (for example, Examples thereof include methyl methacrylate and ethyl methacrylate) and vinyl acetate.
Specific examples of the ethylene resin include low density polyethylene; medium density polyethylene; high density polyethylene; ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-4-methylpentene-1 copolymer, ethylene -Copolymers of ethylene and α-olefins having 3 to 20 carbon atoms such as hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-decene-1 copolymer; ethylene and conjugated dienes ( For example, butadiene and isoprene); copolymers of ethylene and non-conjugated dienes (eg, 1,4-pentadiene); copolymers of ethylene and acrylic acid, methacrylic acid, vinyl acetate, etc .; and For example, α, β-unsaturated carboxylic acid and derivatives thereof (for example, acrylic acid and methyl acrylate), Can be in phosphate or its derivative (e.g. maleic anhydride) include modified (e.g., graft-modified) resin.

The air ring device of the present invention includes the following ethylene-α-olefin copolymer (A) or ethylene-α-olefin copolymer (A) 1 to 30% by weight, and the ethylene-α-olefin copolymer. In the inflation molding of an ethylene-based resin which is a mixture of 70 to 99% by weight of an ethylene-α-olefin copolymer (B) different from (A), a particularly high transparency improving effect is exhibited. The ethylene-α-olefin copolymer (A) is an ethylene-α-olefin copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 20 carbon atoms. The flow activation energy is 50 kJ / mol or more, the melt flow rate (MFR; the unit is g / 10 minutes) and the melt viscosity (η; the unit is Pa · is an ethylene-α-olefin copolymer satisfying the relationship of the following formula (1).
η <1550 × MFR ^−0.25 −420 Formula (1)
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 3 to 20 carbon atoms is derived from an α-olefin having 3 to 20 carbon atoms, which is a monomer, and is contained in the ethylene-α-olefin copolymer. Unit. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and 1-decene. More preferred are 4-methyl-1-pentene and 1-hexene.

  The content of the structural unit derived from ethylene is usually 50 to 99% by weight with respect to the total weight (100% by weight) of the ethylene-α-olefin copolymer. Content of the structural unit induced | guided | derived from a C3-C20 alpha olefin is 1-50 weight% normally with respect to the total weight (100 weight%) of an ethylene-alpha-olefin copolymer.

  The ethylene-α-olefin copolymer (A) is derived from a monomer other than the structural unit derived from ethylene and the structural unit derived from an α-olefin having 3 to 20 carbon atoms. The structural unit 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.

  The ethylene-α-olefin copolymer (A) is preferably a copolymer of ethylene and an α-olefin having 4 to 10 carbon atoms, and more preferably an ethylene and α having 5 to 10 carbon atoms. -A copolymer with olefin, more preferably a copolymer of ethylene and an α-olefin having 6 to 10 carbon atoms. Examples thereof include an ethylene-1-hexene copolymer, an ethylene-4-methyl-1-pentene copolymer, and an ethylene-1-octene copolymer, and an ethylene-1-hexene copolymer is preferable. A terpolymer of ethylene, an α-olefin having 6 to 10 carbon atoms and 1-butene is also preferable. For example, an ethylene-1-butene-1-hexene copolymer, ethylene-1-butene-4- Examples thereof include a methyl-1-pentene copolymer and an ethylene-1-butene-1-octene copolymer, and an ethylene-1-butene-1-hexene copolymer is more preferable.

  The melt flow rate (MFR, unit is g / 10 minutes) of the ethylene-α-olefin copolymer (A) is usually 0.01 to 20, preferably 0.05 to 10, More preferably, it is 0.1-5, More preferably, it is 0.1-1.

  In the ethylene-α-olefin copolymer (A), the melt flow rate (MFR; the unit is g / 10 min.) Is determined according to the method defined in JIS K7210-1995 at 190 ° C. under a load of 21. It is a value measured at 18N (2.16 Kg). And the polymer which mix | blended antioxidant 1000ppm previously is used for the measurement of said melt flow rate.

The density of the ethylene-α-olefin copolymer (A) is usually 890 to 970 kg / m ³ , and is a value measured according to a method defined in JIS K6760-1981. The density is preferably 905 to 940 kg / m ³ , more preferably 907 to 930 kg / m ³ from the viewpoint of the balance between rigidity and impact strength of the film obtained from the ethylene-α-olefin copolymer of the present invention. m is ^3.

  The ethylene-α-olefin copolymer (A) preferably used in the present invention has a flow activation energy (Ea, the unit is kJ / mol) of 50 kJ / mol or more. Such an ethylene-α-olefin copolymer (A) is an ethylene-α-olefin copolymer having a long chain branch and excellent in melt tension.

  The flow activation energy (Ea) of the ethylene-α-olefin copolymer (A) is more preferably 55 kJ / mol or more, and further preferably 60 kJ / mol or more. From the viewpoint of obtaining sufficient moldability without reducing the melt viscosity at a high temperature and from the viewpoint of obtaining a film having a good appearance, Ea is preferably 100 kJ / mol or less, more preferably 90 kJ / mol. It is as follows.

The activation energy (Ea) of the flow is measured using the Rheometrics Mechanical Spectrometer RMS-800 manufactured by Rheometrics as a viscoelasticity measuring device, and each temperature T (unit is K) measured under the following conditions (1) to (4). The shear rate (ω: unit) of the dynamic viscosity (η; unit is Pa · sec) at 190 ° C. by shifting the dynamic viscoelasticity data in FIG. Is a rad / sec.) This is a numerical value calculated from the Arrhenius type equation of the shift factor (a _T ) when creating a master curve showing dependency, and serves as an index of workability.

Measurement conditions of dynamic viscoelasticity data at each temperature T (K) (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
In addition, an appropriate amount (for example, 1000 ppm or more) of an antioxidant such as Irganox 1076 is blended in advance in the sample, and all measurements are performed under nitrogen.

Arrhenius type equation of shift factor (a _T ) log (a _T ) = Ea / R (1 / T−1 / T ₀ )
(R is a gas constant and T ₀ is a reference temperature (463 K).)
The calculation software includes Rheometrics Rhios V. 4.4.4, and in the Arrhenius plot log (a _T ) − (1 / T), the Ea value when the correlation coefficient r ₂ obtained when performing linear approximation is 0.99 or more is It is set as the activation energy of the flow of the ethylene-α-olefin copolymer of the present invention.

The melt flow rate (MFR; unit is g / 10 minutes) of the ethylene-α-olefin copolymer (A) preferably used in the present invention and the melt viscosity (η; unit at 190 ° C. and a shear rate of 100 rad / sec. Is Pa · sec.) Satisfies the relationship of equation (1).
η <1550 × MFR ^−0.25 −420 Formula (1)
The ethylene-based resin containing such an ethylene-α-olefin copolymer (A) has a small load on the extruder and is excellent in processing stability when subjected to inflation molding.

  The melt viscosity η at a shear rate of 100 rad / sec at 190 ° C. of the ethylene-α-olefin copolymer (A) is a shear melt viscosity measured in the above viscoelasticity measurement.

The relationship between the melt flow rate (MFR) satisfied by the ethylene-α-olefin copolymer (A) and the melt viscosity η at a shear rate of 190 ° C. of 100 rad / sec preferably satisfies the formula (1 ′). It is more preferable to satisfy (1 ″), and it is most preferable to satisfy the formula (1 ′ ″).
η <1500 × MFR ^−0.25 −420 Formula (1 ′)
η <1450 × MFR ^−0.25 −420 Formula (1 ″)
η <1350 × MFR ^−0.25 −420 Formula (1 ′ ″)

  As molecular weight distribution of this ethylene-alpha-olefin copolymer (A), Preferably it is 7.0-25, More preferably, it is 7.5-20, More preferably, it is 11-17. When the molecular weight distribution is too narrow, the extrusion load increases and the extrusion processability is impaired. On the other hand, when the molecular weight distribution is too wide, the blocking resistance of the film may be deteriorated. The molecular weight distribution is a value (Mw / Mn) obtained by calculating a polystyrene-reduced weight average molecular weight (Mw) and a number average molecular weight (Mn) obtained by the gel permeation chromatography measurement and dividing Mw by Mn. )

The chain length distribution curve can be obtained by gel permeation chromatography measurement under the following conditions (1) to (6).
(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

In general, there is a relationship between the melt flow rate (MFR) of the ethylene-α-olefin copolymer and the melt tension, and it is known that the melt tension decreases as the MFR increases.
The ethylene-α-olefin copolymer (A) is a high melt tension ethylene-α-olefin copolymer having a long chain branch, preferably a melt flow rate (MFR; unit is g / 10 min). And the melt tension (MT; unit is cN) at 190 ° C. satisfy the relationship of the following formula (2).
2 x MFR ^-0.59 <MT <40 x MFR ^-0.59 Formula (2)

    If the melt tension is too low, the extrudability may deteriorate, and if the melt tension is too high, it may be difficult to take up at high speed.

The relationship between the melt flow rate (MFR) and the melt tension (MT) satisfied by the ethylene-α-olefin copolymer (A) more preferably satisfies the formula (2 ′) and satisfies the formula (2 ″). More preferably.
2.2 × MFR ^−0.59 <MT <25 × MFR ^−0.59 Formula (2 ′)
2.5 x MFR ^-0.59 <MT <15 x MFR ^-0.59 formula (2 '')

The melt tension (MT; unit is cN) in the above formula (2) is a piston at 190 ° C. and an extrusion speed of 5.5 mm / min using a melt tension tester sold by Toyo Seiki Seisakusho. 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 up by using a roller having a diameter of 50 mm while increasing the rotational speed by 40 rpm / min, the strand is cut. The previous tension value.

The ethylene-α-olefin copolymer (A) is preferably 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. Among them, the chain length A 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).
3.30 <logA <−0.0815 × log (MFR) +4.05 Formula (3)

  When the ethylene-α-olefin copolymer (A) satisfies the relationship of the above formula (3), the melt tension is higher and the extrudability is better, or the extruder load is lower and the extrudability is better. The appearance of the obtained film is excellent.

The relationship between the melt flow rate (MFR) and the chain length A (log A) satisfied by the ethylene-α-olefin copolymer (A) more preferably satisfies the following formula (3 ′), and the formula (3 ″) It is further preferable to satisfy
3.30 <logA <−0.0815 × log (MFR) +4.03 Formula (3 ′)
3.30 <logA <−0.0815 × log (MFR) +4.02 Formula (3 ″)

The chain length distribution curve can be obtained by gel permeation chromatography measurement under the following conditions (1) to (6).
(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.

An ethylene-α-olefin copolymer having a long chain branch usually has a long characteristic relaxation time at 190 ° C., but if it is a little short without being too long, the melt tension is higher and the extrudability is better. Alternatively, the load on the extruder is low, the extrusion processability is excellent, and the extrusion appearance of the film is excellent.
In the ethylene-α-olefin copolymer (A) preferably used in the present invention, the characteristic relaxation time (τ; unit is sec) at 190 ° C. and the MFR satisfy the relationship of the following formula (4). It is more preferable.
2 <τ <8.1 × MFR ^-0.746 formula (4)

The relationship between the melt flow rate (MFR) and the characteristic relaxation time (τ) satisfied by the ethylene-α-olefin copolymer (A) more preferably satisfies the following formula (4 ′), and the formula (4 ″) It is further preferable to satisfy
2 <τ <7.9 × MFR ^−0.746 formula (4 ′)
2 <τ <7.8 × MFR ^-0.746 formula (4 '')

  The characteristic relaxation time (τ) at 190 ° C. is measured at each temperature T (unit) measured under the following conditions (1) to (4) using a Rheometrics Mechanical Spectrometer RMS-800 manufactured by Rheometrics as a viscoelasticity measuring device. Is the shear rate (ω: dynamic viscosity at 190 ° C. (η; unit is Pa · sec) by shifting the dynamic viscoelasticity data in K) based on the temperature-time superposition principle. (The unit is rad / sec.) This is a numerical value calculated when a master curve showing dependency is obtained and the master curve is approximated by the following cross equation.

Measurement conditions of dynamic viscoelasticity data at each temperature T (K) (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
In addition, an appropriate amount (for example, 1000 ppm or more) of an antioxidant such as Irganox 1076 is blended in advance in the sample, and all measurements are performed under nitrogen.

Cloth's approximate expression 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 ratio (MFRR) of the ethylene-α-olefin copolymer (A) is preferably as high as possible from the viewpoint of fluidity, and when it is 60 or more, the extrusion load is lower and the extrusion processability is more excellent.

  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. In the above melt flow rate measurement, a polymer in which 1000 ppm of an antioxidant is blended in advance is used.

The method for producing the ethylene-α-olefin copolymer (A) is a method of copolymerizing ethylene and α-olefin using the following metallocene olefin polymerization catalyst.
The metallocene olefin polymerization catalyst used for the production of the ethylene-α-olefin copolymer (A) includes a promoter support (A), a crosslinked bisindenyl zirconium complex (B), an organoaluminum compound (C), and A catalyst obtained by contacting an electron donating compound (D), wherein the promoter support (A) is diethyl zinc (a), two types of fluorinated phenols (b) and (c), water (d), It is a carrier obtained by contacting inorganic compound particles (e) and (f) trimethyldisilazane (((CH ₃ ) ₃ Si) ₂ NH).

The two types of fluorinated phenols (b) and (c) are preferably pentafluorophenol and trifluorophenol.
The inorganic compound particles (e) are preferably silica gel.

The amount of each compound (a), (b), (c), (d) used is not particularly limited, but the molar ratio of the amount of each compound used is (a) :( b) :( c) :( d) = 1: When the molar ratio is x: y: z, it is preferable that x, y and z satisfy the following formula (7).
| 2- (x + y) -2z | ≦ 1 Formula (7)
(X + y) in the above formula (7) is preferably a number of 0.01 to 1.99, more preferably a number of 0.10 to 1.80, and still more preferably 0.20 to 1.50. Most preferably, the number is 0.30 to 1.00.

The amount of (e) used for (a) is the amount of zinc atoms derived from (a) contained in the particles obtained by contact between (a) and (e). The amount of zinc atoms contained is preferably 0.1 mmol or more, more preferably 0.5 to 20 mmol. The amount of (f) used for (e) is preferably (f) 0.1 mmol or more per gram of (e), 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 electron donating compound (D) is preferably triethylamine or trinormaloctylamine.

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.
Moreover, the usage-amount of an electron-donating compound (D) is 0.1-10 mol% with respect to the number-of-moles of the aluminum atom of an organoaluminum compound (C).

The polymerization method is preferably a continuous polymerization method involving the formation of ethylene-α-olefin copolymer particles, for example, continuous gas phase polymerization, continuous slurry polymerization, continuous bulk polymerization, preferably continuous 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 of supplying each component of the metallocene-based olefin polymerization catalyst used for the production of the ethylene-α-olefin copolymer to the reaction vessel, usually, inert gas such as nitrogen and argon, hydrogen, ethylene, etc. are used. Then, a method of supplying in a state free from moisture, or a method of supplying each component in a solution or slurry after dissolving or diluting each component in a solvent is used. 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 prepolymerized catalyst component 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.

  The ethylene-α-olefin copolymer (A) obtained by polymerization by the method as described above can be formed into pellets by a method of kneading by the following continuous extrusion granulation method.

  One of the methods for pelletizing the ethylene-α-olefin copolymer (A) was provided with an extension flow kneading (EFM) die developed by Utracki et al. Described in US Pat. No. 5,451,106. In this method, strands are continuously formed using an extruder, and the strands are continuously cut to produce pellets. Moreover, as another method, the method of forming a strand continuously using the extruder provided with the different direction biaxial screw which has a gear pump, cutting the strand continuously, and manufacturing as a pellet is mentioned. In the latter, it is preferable that there is a staying part between the screw part and the die.

In the present invention, the ethylene-α-olefin copolymer (A) described above as an ethylene-based resin and the ethylene-α-olefin copolymer (B) different from the ethylene-α-olefin copolymer (A) are used. When the mixture is used, the ethylene-α-olefin copolymer (B) may be a copolymer different from the ethylene-α-olefin copolymer (A), and the polymerization method and physical properties are particularly limited. Instead, it is usually an ethylene-α-olefin copolymer (B) having an MFR of 0.1 (g / 10 min) and a density of 880 to 940 (kg / m ³ ).

Next, the present invention will be described by examples.
The evaluation method of physical properties is as follows.
(1) MFR
According to the method prescribed | regulated to JISK7210-1995, it measured on 190 degreeC and the conditions of load 21.18N (2.16Kg).
(2) HAZE
It measured according to JIS K7105. The lower this value, the better the transparency of the film.

[Example 1]
[Preparation of catalyst components]
(1) Silica treatment A reactor equipped with a nitrogen-substituted stirrer was heated at 300 ° C. under a flow of 24 kg toluene and 300 ° C. (Sypolol 948 manufactured by Devison; average particle size = 55 μm; pore volume = 1. 67 ml / g; specific surface area = 325 m ² / g) 2.8 kg was added and stirred. Then, after cooling to 5 ° C., a mixed solution of 0.91, 1 kg of 1,1,1,3,3,3-hexamethyldisilazane and 1.43 kg of toluene was maintained in 33 minutes while maintaining the reactor temperature at 5 ° C. It was dripped. After completion of dropping, the mixture was stirred at 5 ° C. for 1 hour and at 95 ° C. for 3 hours. Thereafter, the obtained solid product was washed 6 times with 21 kg of toluene. Thereafter, 6.9 kg of toluene was added and allowed to stand overnight.

(2) Synthesis of promoter support (A) To the slurry obtained above, 2.05 kg of a 50 wt% diethylzinc hexane solution and 1.3 kg of hexane were added and stirred. Then, after cooling to 5 ° C., a mixed solution of 0.77 kg of pentafluorophenol and 1.17 kg of toluene was added dropwise over 61 minutes while keeping the temperature of the reactor at 5 ° C. After completion of dropping, the mixture was stirred at 5 ° C. for 1 hour and at 40 ° C. for 1 hour. Thereafter, 0.11 kg of H ₂ O was added dropwise over 1.5 hours while maintaining the temperature of the reactor at 5 ° C. After completion of dropping, the mixture was stirred at 5 ° C. for 1.5 hours and at 55 ° C. for 2 hours. Thereafter, 1.4 kg of a 50 wt% diethylzinc hexane solution and 0.8 kg of hexane were added at room temperature. After cooling to 5 ° C., a mixed solution of 0.44 kg of 3,4,5-trifluorophenol and 0.77 kg of toluene was added dropwise over 60 minutes while maintaining the temperature of the reactor at 5 ° C. After completion of dropping, the mixture was stirred at 5 ° C. for 1 hour and at 40 ° C. for 1 hour. Thereafter, 0.077 kg of H ₂ O was added dropwise over 1.5 hours while maintaining the temperature of the reactor at 5 ° C. After completion of dropping, the mixture was stirred at 5 ° C for 1.5 hours, at 40 ° C for 2 hours, and further at 80 ° C for 2 hours. Stirring was stopped, the supernatant liquid was extracted to a residual amount of 16 L, 11.6 kg of toluene was added, and the mixture was stirred. The temperature was raised to 95 ° C. and stirred for 4 hours. The obtained solid product was washed 4 times with 20.8 kg of toluene and 3 times with 24 liters of hexane. Thereafter, the promoter support (A) was obtained by drying.
[Preparation of prepolymerization catalyst]
Into an autoclave with a stirrer having an internal volume of 210 liters, which was previously purged with nitrogen, 0.55 kg of the above-mentioned promoter support (A) was charged and charged with 3 liters of hydrogen at normal temperature and normal pressure and 80 liters of butane. The temperature was raised to ° C. Further, ethylene was charged by 0.02 MPa as the gas phase pressure in the autoclave, and after the system was stabilized, 165 mmol of triisobutylaluminum and 55 mmol of racemic-ethylenebis (1-indenyl) zirconium diphenoxide were added to initiate polymerization. . While raising the temperature to 32 ° C., the temperature was further raised to 50 ° C. while continuously supplying ethylene and hydrogen, and prepolymerization was carried out for a total of 4 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, whereby 16 g of ethylene-1-butene copolymer was prepolymerized per 1 g of the promoter support (A). A prepolymerized catalyst component was obtained.

[polymerization]
Using the preliminary polymerization catalyst component obtained above, ternary copolymerization of ethylene, 1-butene and 1-hexene was carried out in a continuous fluidized bed gas phase polymerization apparatus. The polymerization conditions were a temperature of 75 ° C., a hydrogen molar ratio to ethylene of 2 MPa in total pressure of 0.9%, and a 1-hexene molar ratio to ethylene of 1.9%. In order to keep the gas composition constant during polymerization, ethylene, 1 -Hexene and hydrogen were continuously supplied. The prepolymerized catalyst component and triisobutylaluminum are continuously supplied, and ethylene-1-butene-1 is produced with an average polymerization time of 4 hr and a production efficiency of 21 kg / hr so as to maintain a constant total powder weight of 80 kg in the fluidized bed. -A hexene copolymer powder was obtained. Table 1 shows the physical property values of the obtained ethylene-1-butene-1-hexene copolymer.

[Production of resin composition]
Using the LCM50 extruder manufactured by Kobe Steel, the ethylene-1-butene-1-hexene copolymer powder obtained above was fed at a feed rate of 50 kg / hr, a screw rotation speed of 450 rpm, a gate opening of 50%, and a suction pressure. Pellets were obtained by granulation under conditions of 0.1 MPa and a resin temperature of 200 to 230 ° C.

[Film forming]
20 parts of ethylene-1-butene-1-hexene copolymer pellets as the ethylene-α-olefin copolymer (A) and ethylene-1-butene as the ethylene-α-olefin copolymer (B) An ethylene resin blended with 80 parts of pellets of a copolymer (Sumikasen L FS150 MFR = 1.1 g / 10 min density 921 kg / m ³ ) was used as an inflation molding machine (annular die resin outlet) A film was formed by attaching an air ring device having guide vanes to a diameter Dd of 125 (mm) and an extruder screw diameter: 55 (mm). The air ring device has a No. 1 chamber ring (inner diameter: 285 mm) at the upper part of the blow ring, and further No. 1. A type having a No. 2 chamber ring (inner diameter: 325 mm) outside the one chamber ring was used, and guide vanes were arranged on the inner surface of each chamber ring. An aluminum plate having a thickness of 200 (μm) was used for the guide blade. In the No. 1 chamber ring, the height of the guide vane from the inner surface of the chamber ring was 15 (mm), the length per sheet was 90 (mm), and eight sheets were installed at equal intervals. In the No. 2 chamber ring, the height of the guide vane from the inner surface of the chamber ring was 30 (mm), the length per sheet was 110 (mm), and eight sheets were installed at equal intervals. Each guide blade was provided with a slight curvature so that the convex surface was on the top. The installation angle of the guide vanes was such that the angle (α) with the annular die discharge surface was 60 ° in the No. 1 chamber ring, and the angle (α) was 30 ° in the No. 2 chamber ring.
The ethylene resin was put into an extruder, melted and kneaded at a temperature of 190 (° C), led to a 200 (° C) annular die, and extruded from an annular lip. The lip gap was 2.0 (mm) and BUR was 2.0. The extruded tube-shaped film was molded while supplying a cooling medium using the air ring device and cooling the outer surface of the tubular film so that the cooling medium flowed in a spiral shape. When one end of the yarn was stuck in the chamber ring and the flow of the cooling medium was examined, it was confirmed that the yarn was blown upward while being inclined in the circumferential direction of the chamber ring. The thickness of the film to be produced was 20 (μm) and the extrusion rate was 50 (kg / h).
At this time, the rotation speed (frequency) of the blower sending air to the air ring was 54 (Hz). The transparency of the obtained film is shown in Table 2.

[Comparative Example 1]
A film was produced using the same apparatus and the same conditions as in Example 1 except that no guide vanes were arranged on the chamber ring. The rotation speed (frequency) of the blower that sends air to the air ring is limited to 41 (Hz). If the rotation speed is increased more than this, the bubbles become unstable and cannot be molded. When one end of the yarn was stuck in the chamber ring and the flow of the cooling medium was examined, it was confirmed that the yarn was blown upward along the flow direction of the tubular film. The transparency of the film is shown in Table 2.

The figure which shows the manufacturing method of the inflation film using the conventional air ring apparatus The figure which shows the manufacturing method of the inflation film using the air ring apparatus of this invention The example of the plane development which cut the chamber ring provided with the guide vane in the air ring device of the present invention perpendicularly to the annular die discharge surface Another example of a developed plan view of a chamber ring provided with guide vanes in the air ring device of the present invention cut perpendicularly to the annular die discharge surface (A) No. used in Example 1 FIG. 3B is a plan development view in which the one-chamber ring is cut perpendicularly to the annular die discharge surface. Plane development of 2-chamber ring cut perpendicularly to the annular die discharge surface

Explanation of symbols

1 Ring Die 2 Tubular Film 3 Air Ring Body 4 Chamber Ring (No. 1)
5 Chamber ring (No. 2)
6 Blowout ring 7 Guide vane 8 Angle between guide vane and annular die discharge surface (α)

Claims (5)

  An air ring device used in inflation molding to obtain a tubular film by melting and kneading a thermoplastic resin with an extruder and extruding it from an annular die, and an air ring body and a blow ring for spraying a cooling medium onto the tubular film An air ring device comprising a chamber ring for adjusting the flow of the sprayed cooling medium, the chamber ring comprising guide vanes arranged on the outer surface of the tubular film so that the cooling medium flows spirally. Air ring device.   In the manufacturing method of the inflation film which obtains a tubular film by melt-kneading a thermoplastic resin with an extruder and extruding from an annular die, the air ring apparatus of Claim 1 is applied to the tubular film extruded from the annular die. A method for producing an inflation film, characterized in that the cooling medium is supplied to the outer surface of the tubular film so as to flow in a spiral shape to cool the tube-like film.   The method for producing an inflation film according to claim 2, wherein the thermoplastic resin is an ethylene-based resin. The ethylene-based resin is an ethylene-α-olefin copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 20 carbon atoms, and the flow activation energy is The melt flow rate (MFR; the unit is g / 10 minutes) and the melt viscosity (η; the unit is Pa · sec) at a shear rate of 190 rad / sec at 190 ° C. are 50 kJ / mol or more. 1 to 30% by weight of an ethylene-α-olefin copolymer (A) satisfying the relationship of formula (1) and an ethylene-α-olefin copolymer (A) different from the ethylene-α-olefin copolymer (A) ( The method for producing an inflation film according to claim 3, which is a mixture of B) 70 to 99% by weight.
η <1550 × MFR ^−0.25 −420 Formula (1) The ethylene-based resin is an ethylene-α-olefin copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 20 carbon atoms, and the flow activation energy is The melt flow rate (MFR; the unit is g / 10 minutes) and the melt viscosity (η; the unit is Pa · sec) at a shear rate of 190 rad / sec at 190 ° C. are 50 kJ / mol or more. ethylene -α- olefin copolymer satisfying the relationship of formula (1) manufacturing method η <1550 × MFR ^-0.25 -420 formula blown film according to claim 3, wherein the (a) (1)

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