JP2010116567A - Polyolefin-based resin film and bag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin-based resin film excellent in a slipping property and transparency, and a bag formed by using the same. <P>SOLUTION: An ethylene-α-olefin copolymer has a monomer unit based on ethylene, and monomer unit based on 3-20C α-olefin. The polyolefin-based resin film has a layer containing the ethylene-α-olefin copolymer on at least one surface, in which activation energy (Ea) of flow is ≥35 kJ/mol, melt flow rate ratio (MFRR) is ≥30, and molecular weight distribution (Mz/Mw) expressed by a ratio of Z-average molecular weight (Mz) and weight-average molecular weight (Mw) is ≥3.4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyolefin resin film and a bag using the film.

Polyolefin resin films such as polyethylene resins and polypropylene resins are used as various packaging films. Transparency is required for the film used for the purpose of confirming the packaged body. For example, a film made of a polyethylene resin in which high-pressure radical polymerization low-density polyethylene and high-density polyethylene are blended (see, for example, Patent Document 1).
), And a film made of a polyethylene resin in which a linear low density polyethylene and a high density polyethylene are blended (for example, see Patent Document 2).

Japanese Examined Patent Publication No. 7-61683 JP-A-10-237187

However, a film made of a conventional polyolefin resin is difficult to slip when packing an article to be packaged, so that workability is reduced, and when the film is used as a bag, the opening of the bag is poor. In some cases, the slipperiness was not satisfactory.
Under such circumstances, the problem to be solved by the present invention is to provide a polyolefin resin film excellent in slipperiness and transparency and a bag using the film.

  According to the present invention, it is possible to provide a polyolefin resin film excellent in slipperiness and transparency and a bag using the film.

  A first aspect of the present invention is an ethylene-α-olefin copolymer having a monomer unit based on ethylene and a monomer unit based on an α-olefin having 3 to 20 carbon atoms, wherein the flow activation The energy (Ea) is 35 kJ / mol or more, the melt flow rate ratio (MFRR) is 30 or more, and the molecular weight distribution (Mz /) represented by the ratio of the Z average molecular weight (Mz) to the weight average molecular weight (Mw). This is a polyolefin-based resin film having a layer containing an ethylene-α-olefin copolymer having Mw) of 3.4 or more on at least one surface.

  The second of the present invention relates to a bag made of the above film.

The polyolefin resin film of the present invention is a film having a surface layer (S) composed of a layer containing a polyolefin resin on at least one side, and the surface layer (S) satisfies the following requirements (R1) and (R2): It is a film having a satisfactory surface roughness.
(R1): The surface roughness intensity (I _0.4-20 ) of the surface roughness component having a wavelength of 0.4 to _{20 μm} is 2000 nm ² or more.
(R2): Surface roughness of a surface roughness component having a wavelength of 0.4 to 2.0 μm in a surface roughness intensity (I _0.4-20 ) of a surface roughness component having a wavelength of 0.4 to 20 μm The ratio of strength (I _0.4-2 ) is 15% or more.

The polyolefin resin of the surface layer (S) is a resin having 50% by weight or more of monomer units based on olefin, and examples thereof include a polyethylene resin, a polypropylene resin, and a polybutene resin. As the polyolefin resin, a polyethylene resin is preferably used, and examples thereof include an ethylene homopolymer, an ethylene-α-olefin copolymer, an ethylene-vinyl ester copolymer, and an ethylene-unsaturated carboxylic acid ester copolymer. be able to.
In these, the ethylene-alpha-olefin copolymer mentioned later is used suitably.

The surface layer (S) has a surface roughness whose surface roughness intensity (I _0.4-20 ) of a surface roughness component having a wavelength of 0.4 to _{20 μm} is 2000 nm ² or more (requirement (R1)). When the I _0.4-20 is too small, there may be poor in sliding property, preferably at 2200 nm ² or more, more preferably 2300 nm ² or more. The I _0.4-20 is usually 10000 nm ² or less, from the viewpoint of enhancing the transparency, preferably not more 7000 nm ² or less, more preferably 5000 nm ² or less.

The surface layer (S) has a surface roughness with a wavelength of 0.4 to 2.0 μm in a surface roughness intensity (I _0.4-20 ) of a surface roughness component having a wavelength of 0.4 to 20 μm. The surface roughness strength (I _0.4-2 ) has a surface roughness of 15% or more (requirement (R2)). However, I _0.4-20 shall be 100%. When the ratio is too small, the transparency may be inferior, preferably 18% or more, and more preferably 20% or more.

The surface roughness of the film is measured using a scanning probe microscope (for example, D-3000 type manufactured by Digital Instruments), and specifically, measured under the following conditions.
Scanning mode: Intermittent contact mode (tapping mode, dynamic mode, cyclic contact mode, etc.)
Probe frequency: resonance frequency around 300 kHz Scanning speed: 0.5 Hz (when scanning range is 100 μm × 100 μm)
1 Hz (when scanning range is 10 μm × 10 μm)
Set point ratio: Usually around 0.6 (Here, the set point ratio is the vibration amplitude of the probe when it is sufficiently far from the sample surface so that the oscillated probe does not come into contact with the sample surface. A value obtained by Asp / Ao, where Asp (V) is the vibration amplitude of the probe when the surface roughness is measured while the probe is brought close to the sample surface and the tip of the tip is contacted with the sample surface intermittently. (Note that the tip is a portion with a sharp tip attached to the tip of the probe, and in a scanning probe microscope, this is measured by interacting with the sample surface.)
Measurement environment: room temperature, atmospheric observation image: height image Number of pixels: 512 × 512 pixels In addition, in surface roughness measurement, the surface of the sample is usually removed by washing the surface in advance with a solvent that does not attack the sample. Then, remove the electrification of the sample with a static eliminating blower or the like. Moreover, in order to eliminate the influence of vibration from the floor and the influence of noise, it is preferable to install the device on a vibration isolator having a soundproof cover that can be sealed, and to seal the soundproof cover during measurement.

  In order to correct the inclination of the sample, the obtained surface roughness curve is corrected so that the inclination of the center line of the surface roughness curve becomes horizontal. The correction may be performed using a commercially available program. For example, the Flatten function (Flatten Order 1) in the off-line analysis function of the NanoScope IIIa controller for scanning probe microscope manufactured by Digital Instruments is available. Can be used.

The surface roughness intensity I _0.4-20 of the film is obtained by _converting the surface roughness curve obtained from the measurement result of the above scanning range 100 μm × 100 μm into 256 sinusoidal curves (hereinafter referred to as the basic curve) having a wavelength of L / n. As a composite curve, each amplitude (unit: nm) of the basic curve is obtained, and the square of the amplitude of the basic curve having a wavelength of 0.4 to 20 μm is summed. Here, L is the length of one side of the scanning range (100 μm), and n is an integer from 1 to N / 2 (N is the number of pixels on one side of the scanning range (512 pixels)). The surface roughness intensity I _0.4-2 of the film is the square value of the amplitude of the basic curve having the wavelength of 0.4 to 2.0 μm among the basic curves having the wavelength of 0.4 to 20 μm. It is the summed value. The calculation of the amplitude of the basic curve may be performed using a commercially available program, such as, for example, Power Spectral Density in the off line analysis function of the NanoScope IIIa controller for scanning probe microscopes manufactured by Digital Instruments. An analysis function can be used.

The surface layer (S) has a surface roughness strength (I _0.1-2 of a surface roughness component having a wavelength of 0.1 to 2.0 μm from the viewpoint of improving slipperiness while maintaining good transparency of the film. ) Preferably has a surface roughness of 470 nm ² or more, more preferably I _0.1-2 has a surface roughness of 500 nm ² or more (requirement (R3)). The I _0.1-2 is usually 1000 nm ² or less.

The surface layer (S) has a surface roughness strength (I _0.1-2 of a surface roughness component having a wavelength of 0.1 to 2.0 μm from the viewpoint of improving slipperiness while maintaining good transparency of the film. ), The ratio of the surface roughness strength (I _0.1-1 ) of the surface roughness component having a wavelength of 0.1 to 1.0 μm is preferably 40% or more. The ratio of the surface roughness strength (I _0.1-1 ) of the uneven wavelength of _0.1 to 1.0 μm in the surface roughness strength (I _0.1-2 ) of the uneven wavelength of 1 to 2.0 μm is 50% or more. It is more preferable to have a surface roughness of (requirement (R4)).

The surface roughness intensity I _0.1-2 of the film is obtained by _converting the surface roughness curve obtained from the measurement result of the above scanning range of 10 μm × 10 μm into 256 sinusoidal curves (hereinafter referred to as the basic curve and L / n wavelength). As a composite curve, each amplitude (unit: nm) of the basic curve is obtained, and the square of the amplitude of the basic curve having a wavelength of 0.1 to 2.0 μm is summed. Here, L: the length of one side of the scanning range (10 μm), n: an integer from 1 to N / 2 (N is the number of pixels on one side of the scanning range (512 pixels)). The surface roughness intensity I _0.1-1 of the film is the square of the amplitude of the basic curve having the wavelength of 0.1 to 1.0 μm among the basic curves having the wavelength of 0.1 to 2.0 μm. This is the sum of the values. The calculation of the amplitude of the basic curve may be performed using a commercially available program, such as, for example, Power Spectral Density in the off line analysis function of the NanoScope IIIa controller for scanning probe microscopes manufactured by Digital Instruments. An analysis function can be used.

  The polyolefin resin film of the present invention is an ethylene-α-olefin copolymer having a monomer unit based on ethylene and a monomer unit based on an α-olefin having 3 to 20 carbon atoms, The molecular weight represented by the ratio of the Z average molecular weight (Mz) to the weight average molecular weight (Mw), wherein the flow activation energy (Ea) is 35 kJ / mol or higher, the melt flow rate ratio (MFRR) is 30 or higher. It is a film having a layer containing an ethylene-α-olefin copolymer having a distribution (Mz / Mw) of 3.4 or more on at least one surface.

  Examples of the α-olefin having 3 to 20 carbon atoms of the ethylene-α-olefin copolymer include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene and the like can be mentioned, and these may be used alone or in combination of two or more. 1-butene and 1-hexene are preferable, and 1-butene is more preferable.

  Examples of the ethylene-α-olefin copolymer include an ethylene-propylene copolymer, an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, an ethylene-1-octene copolymer, and ethylene. -1-butene-1-hexene copolymer, ethylene-1-butene-1-octene copolymer, and the like, preferably ethylene-1-butene copolymer, ethylene-1-hexene copolymer, An ethylene-1-butene-1-hexene copolymer, most preferably an ethylene-1-butene copolymer.

  The content of the monomer unit based on ethylene in the ethylene-α-olefin copolymer is usually 50 to 99% by weight with respect to the total weight (100% by weight) of the ethylene-α-olefin copolymer. It is. The content of the monomer unit based on the α-olefin is usually 1 to 50% by weight with respect to the total weight (100% by weight) of the ethylene-α-olefin copolymer.

  Components measured under conditions of a temperature of 190 ° C. and a load of 21.18 N specified in JIS K7210 The melt flow rate (MFR) of the ethylene-α-olefin copolymer is usually 0.01 to 100 g / 10 min. It is. From the viewpoint of enhancing the extrusion moldability, it is preferably 0.05 g / 10 min or more, more preferably 0.07 g / 10 min or more. Moreover, from a viewpoint of improving the intensity | strength of a film and a bag, Preferably it is 10 g / 10min or less, More preferably, it is 7.0 g / 10min or less, More preferably, it is 5.0 g / 10min or less.

The density of the ethylene-α-olefin copolymer is usually 890 to 970 kg / m ³ . From the viewpoint of enhancing the film and strength of the bag, preferably at 945 kg / m ³ or less, more preferably 935 kg / m ³ or less. Further, in view of enhancing the rigidity of the film and bags, is preferably 910 kg / m ³ or more, more preferably 915 kg / m ³ or more. The density is measured according to a method defined in JIS K7112 using a sample subjected to annealing described in JIS K6760.

  The ethylene-α-olefin copolymer preferably has a flow activation energy (Ea) of 35 kJ / mol or more and a melt flow rate ratio (MFRR) of 30 or more.

  The ethylene-α-olefin copolymer is an ethylene-α-olefin copolymer having a long chain branch and excellent in melt tension, and such an ethylene-α-olefin copolymer is conventionally known. Compared to ordinary ethylene-α-olefin copolymers, the flow activation energy (Ea) is high and the melt flow rate ratio (MFRR) is high. Conventionally known Ea of a normal ethylene-α-olefin copolymer is usually lower than 35 kJ / mol, MFRR is usually smaller than 30, and is inferior in extrusion moldability and inflation moldability, A bag using the copolymer may be inferior in strength. The melt flow rate ratio (MFRR) is the melt flow rate measured under the conditions of a temperature of 190 ° C. and a load of 211.8 N specified in JIS K7210, a temperature of 190 ° C. and a load of 21 specified in JIS K7210. The value divided by the melt flow rate measured under the condition of 18N.

  The above-mentioned ethylene-α-olefin copolymer is represented by the ratio of the Z average molecular weight (Mz) and the weight average molecular weight (Mw) from the viewpoint of improving slipperiness while maintaining good transparency of the film. An ethylene-α-olefin copolymer having a molecular weight distribution (Mz / Mw) of 3.4 or more is preferred. In addition, Z average molecular weight (Mz) and weight average molecular weight (Mw) are the values of polystyrene conversion measured by the gel permeation chromatography method.

  Ea of the ethylene-α-olefin copolymer is more preferably 40 kJ / mol or more, further preferably 50 kJ / mol or more, particularly preferably from the viewpoint of further improving the extrusion moldability and inflation moldability. 60 kJ / mol or more. Further, from the viewpoint of further improving the inflation moldability and further enhancing the transparency of the film and the bag, Ea is preferably 100 kJ / mol or less, more preferably 90 kJ / mol or less.

The flow activation energy (Ea) is a master curve showing the dependence of the melt complex viscosity (unit: Pa · sec) at 190 ° C. on the angular frequency (unit: rad / sec) based on the temperature-time superposition principle. Is a numerical value calculated by the Arrhenius equation from the shift factor (a _T ) at the time of creating the value, and is a value obtained by the following method. That is, the melt complex viscosity-angular frequency curve of the ethylene-α-olefin copolymer at temperatures of 130 ° C., 150 ° C., 170 ° C. and 190 ° C. (T, unit: ° C.) (the unit of melt complex viscosity is Pa · sec. The unit of the angular frequency is rad / sec.), Based on the temperature-time superposition principle, for each melt complex viscosity-angular frequency curve at each temperature (T), The shift factor (a _T ) at each temperature (T) obtained when superposed on the melt complex viscosity-angular frequency curve of the coalescence is obtained, and each temperature (T) and the shift factor at each temperature ( _T ) are obtained. From (a _T ), a first-order approximate expression (formula (I) below) of [ln (a _T )] and [1 / (T + 273.16)] is calculated by the method of least squares. Next, Ea is obtained from the slope m of the linear expression and the following expression (II).
ln (a _T ) = m (1 / (T + 273.16)) + n (I)
Ea = | 0.008314 × m | (II)
a _T : Shift factor Ea: Activation energy of flow (unit: kJ / mol)
T: Temperature (unit: ° C)
For the calculation, commercially available calculation software may be used. As the calculation software, Rheos V. manufactured by Rheometrics is used. 4.4.4.
The shift factor (a _T ) is obtained by moving the logarithmic curve of the melt complex viscosity-angular frequency at each temperature (T) in the log (Y) = − log (X) axis direction (however, the Y axis Is the complex viscosity of the melt, and the X axis is the angular frequency.), And the amount of movement when superposed on the melt complex viscosity-angular frequency curve at 190 ° C., in the superposition, melting at each temperature (T) The logarithmic curve of complex viscosity-angular frequency shifts the angular frequency by a _T times and the melt complex viscosity by 1 / a _T times for each curve. Moreover, the correlation coefficient when calculating | requiring (I) Formula by the least squares method from the value of four points | pieces, 130 degreeC, 150 degreeC, 170 degreeC, and 190 degreeC is usually 0.99 or more.

  The melt complex viscosity-angular frequency curve is measured using a viscoelasticity measuring apparatus (for example, Rheometrics Mechanical Spectrometer RMS-800 manufactured by Rheometrics), and usually geometry: parallel plate, plate diameter: 25 mm, plate interval: 1. It is performed under the conditions of 5 to 2 mm, strain: 5%, angular frequency: 0.1 to 100 rad / sec. The measurement is performed in a nitrogen atmosphere, and it is preferable that an appropriate amount (for example, 1000 ppm) of an antioxidant is added to the measurement sample in advance.

  The MFRR of the ethylene-α-olefin copolymer is more preferably 35 or more from the viewpoint of further improving the extrusion moldability and the inflation moldability. Moreover, from the viewpoint of further increasing the strength of the film and the bag, the MFRR is preferably 500 or less, more preferably 400 or less.

From the viewpoint of further enhancing the extrusion moldability, the above ethylene-α-olefin copolymer has a melt complex viscosity at a temperature of 190 ° C. and an angular frequency of 100 rad / sec as η * (unit: Pa · sec) and conforms to JIS K7210. It is preferable to satisfy the following formula (1) with the melt flow rate measured under the conditions of a specified temperature of 190 ° C. and a load of 21.18 N as MFR (unit: g / 10 minutes),
η * <1550 × MFR ^−0.25 −420 Formula (1)
More preferably, the following formula (1-2) is satisfied,
η * <1500 × MFR ^−0.25 −420 Formula (1-2)
More preferably, the following formula (1-3) is satisfied,
η * <1450 × MFR ^−0.25 −420 Formula (1-3)
It is particularly preferable that the following formula (1-4) is satisfied.
η * <1350 × MFR ^−0.25 −420 Formula (1-4)
Note that η * is measured under the same conditions as in the viscoelasticity measurement for obtaining Ea.

  The ethylene-α-olefin copolymer is represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) from the viewpoint of enhancing the extrusion moldability and the transparency of the film and the bag. An ethylene-α-olefin copolymer having a molecular weight distribution (Mw / Mn) of 5 to 30 is preferred. The molecular weight distribution (Mw / Mn) is more preferably 7 to 20, and still more preferably 8 to 20. In addition, a weight average molecular weight (Mw) and a number average molecular weight (Mn) are the values of polystyrene conversion measured by the gel permeation chromatography method.

From the viewpoint of improving the extrusion moldability and inflation moldability, the above ethylene-α-olefin copolymer has an MFR of a melt flow rate measured under conditions of a temperature of 190 ° C. and a load of 21.18 N as defined in JIS K7210. It is preferable that the following formula (2) is satisfied, where (unit: g / 10 minutes) is set, and the melt tension at 190 ° C. is MT (unit: cN).
2 x MFR ^-0.59 <MT <40 x MFR ^-0.59 Formula (2)
The ethylene-α-olefin copolymer preferably satisfies the following formula (2-2) from the viewpoint of further enhancing the extrusion moldability,
2.2 × MFR ^−0.59 <MT Formula (2-2) It is more preferable to satisfy the following Formula (2-3).
2.5 × MFR ^−0.59 <MT Formula (2-3) The above-mentioned ethylene-α-olefin copolymer preferably satisfies the following Formula (2-4) from the viewpoint of further improving inflation moldability. ,
MT <25 × MFR ^−0.59 Formula (2-4) It is more preferable to satisfy the following Formula (2-5).
MT <15 × MFR− ^0.59 formula (2-5) Note that the conventional ordinary ethylene-α-olefin copolymer does not normally satisfy the left side of the formula (2).

The above ethylene-α-olefin copolymer has a temperature of 190 ° C. and a load of 21.18 N as defined in JIS K7210 from the viewpoint of enhancing extrusion molding and inflation moldability, and enhancing the strength and transparency of films and bags. It is preferable to satisfy the following formula (3), where the melt flow rate measured under the conditions is MFR (unit: g / 10 min) and the intrinsic viscosity is [η] (unit: dl / g).
1.02 × MFR ^−0.094 <[η] <1.50 × MFR ^−0.156 Formula (3)
The ethylene-α-olefin copolymer preferably satisfies the following formula (3-2) from the viewpoint of further enhancing the strength and transparency of the film and bag,
1.05 × MFR ^−0.094 <[η] It is more preferable that the following formula (3-3) is satisfied.
1.08 × MFR ^−0.094 <[η] Formula (3-3) From the viewpoint of further enhancing the extrusion moldability and inflation moldability, the above-described ethylene-α-olefin copolymer is expressed by the following formula (3-4). More preferably,
[Η] <1.47 × MFR ^−0.156 Formula (3-4) It is more preferable to satisfy the following Formula (3-5).
[Η] <1.42 × MFR ^−0.156 formula (3-5) In addition, conventional ethylene having the same melt flow rate measured under conditions of a temperature of 190 ° C. and a load of 21.18 N as defined in JIS K7210 When the α-olefin copolymer is compared with the ethylene-α-olefin copolymer, the intrinsic viscosity of the conventional ethylene-α-olefin copolymer is the same as that of the ethylene-α-olefin copolymer. The value is usually higher than the intrinsic viscosity.

  As the method for producing the ethylene-α-olefin copolymer, the presence of a catalyst obtained by contacting the following promoter support (A), the crosslinked bisindenyl zirconium complex (B) and the organoaluminum compound (C) Below, the method of copolymerizing ethylene and a C3-C20 alpha olefin is mention | raise | lifted.

The promoter support (A) comprises (a) diethylzinc, (b) fluorinated phenol, (c) water, (d) silica and (e) trimethyldisilazane (((CH ₃ ) ₃ Si) ₂ NH). It is a carrier obtained by contact.

The amount of each component (a), (b), (c) used is not particularly limited, but the molar ratio of the amount of each component used is the component (a): component (b): component (c) = 1: When y: z, y and z preferably satisfy the following formula.
| 2-y-2z | ≦ 1
Y in the above formula 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. Most preferably, the number is 0.30 to 1.00.

  The amount of component (d) used relative to component (a) is such that the number of moles of zinc atoms contained in the particles obtained by contacting component (a) and component (d) is 1 g of the particles. The amount is preferably 0.1 mmol or more, and more preferably 0.5 to 20 mmol. The amount of the component (e) to be used with respect to the component (d) is preferably an amount that makes the component (e) 0.1 mmol or more per 1 g of the component (d), and an amount that becomes 0.5 to 20 mmol. More preferably.

  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 per 1 g of the promoter support (A). The amount of the organoaluminum compound (C) used is preferably such that the aluminum atom of the organoaluminum compound (C) is 1 to 2000 moles per mole of zirconium atoms in the cross-linked bisindenyl zirconium complex (B). is there.

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 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. And a method in which the components are supplied without moisture, and 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 prepolymerized catalyst component as a catalyst component or catalyst for the main polymerization.

  The polymerization temperature is usually lower than the temperature at which the ethylene-α-olefin copolymer melts, preferably 0 to 150 ° C, more preferably 30 to 100 ° C. Further, from the viewpoint of enhancing the slipperiness of the film, a more preferable reaction temperature is 80 to 95 ° C, and most preferably 83 to 90 ° 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 polyolefin-based resin film of the present invention may contain additives such as antioxidants, anti-blocking agents, lubricants, antistatic agents, pigments, processability improvers; other resins, and the like. Other resin may be used independently and may use 2 or more types together.

  As said antioxidant, a phenolic antioxidant, phosphorus antioxidant, etc. are mentioned. Each may be used alone or in combination of two.

  Examples of the phenolic antioxidant include 2,6-di-t-butyl-4-methylphenol (BHT) and n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl). ) Propionate (trade name Irganox 1076, manufactured by Ciba Specialty Chemicals), pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name Irganox 1010, manufactured by Ciba Specialty Chemicals) ), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (trade name Irganox 3114, manufactured by Ciba Specialty Chemicals), 1,3,5-trimethyl-2,4 , 6-Tris (3,5-di-tert-butyl-4-hydroxyben L) benzene, 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10 -Tetraoxaspiro [5,5] undecane (trade name Sumilizer GA80, manufactured by Sumitomo Chemical Co., Ltd.) and the like.

  From the viewpoint of migrating the antioxidant to the package and reducing the change in the odor and taste of the package due to the antioxidant, the addition amount of the phenolic antioxidant relative to the total weight of the film is preferably 500 ppm or less. Preferably it is 200 ppm or less, Most preferably, it is 0 ppm.

  Examples of the phosphorus-based antioxidant include distearyl pentaerythritol diphosphite (trade name ADK STAB PEP8), tris (2,4-di-t-butylphenyl) phosphite (trade name Irgafos 168, manufactured by Ciba Specialty Chemicals) ), Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylenediphosphonite (trade name Sandostab P- EPQ (manufactured by Clariant Shapin), bis (2-t-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl -4-hydroxy-5-t-butylphenyl) propoxy] dibenzo [d , F] [1, 3, 2] dioxaphosphine (trade name: Sumilizer GP, manufactured by Sumitomo Chemical Co., Ltd.), and the like.

  From the viewpoint of migrating the antioxidant to the package and reducing the odor and taste change of the package due to the antioxidant, the addition amount of the phosphorus antioxidant with respect to the total weight of the film is preferably 500 ppm or less. Preferably it is 200 ppm or less, Most preferably, it is 0 ppm.

  Examples of the anti-blocking agent include inorganic anti-blocking agents and organic anti-blocking agents. Examples of the inorganic anti-blocking agent include silica, diatomaceous earth, talc, aluminosilicate, kaolin, calcium carbonate and the like. Examples of the organic anti-blocking agent include Eposta-MA (manufactured by Nippon Shokubai Co., Ltd.).

  Examples of the lubricant include higher fatty acid amides and higher fatty acid esters.

  From the viewpoint of reducing the change in the odor and taste of the package due to the transfer of the lubricant to the package and the package, the addition amount of the lubricant with respect to the total weight of the film is preferably 1500 ppm or less, more preferably 750 ppm or less, particularly Preferably it is 500 ppm or less, Most preferably, it is 0 ppm.

  Examples of the antistatic agent include glycerin esters and sorbitan acid esters of fatty acids having 8 to 22 carbon atoms, alkyl dialkanolamides of fatty acids having 8 to 22 carbon atoms, polyethylene glycol esters, and alkyldiethanolamines. .

  Examples of the pigment include a white pigment and carbon black.

  Examples of the other resins include polyolefin resins and elastomers.

  The blend of the above-mentioned additives and other resins with a polyolefin resin is melt kneaded by a known method, for example, mixed with a tumbler blender, a Henschel mixer, etc. It is produced by melt-kneading and granulating with an extruder, or melt-kneading with a kneader or Banbury mixer.

  The polyolefin resin film of the present invention is produced by a known molding method, for example, an inflation film molding method, a T-die cast film molding method, or the like. Preferably, an inflation film forming method is used.

  The polyolefin resin film of the present invention may be provided with a layer made of another resin by co-extrusion with another resin, or by bonding with a film made of another resin.

  The polyolefin resin film of the present invention has a thickness of usually 5 to 200 μm, preferably 10 to 150 μm, more preferably 20 to 100 μm.

  The bag of the present invention is a bag formed using the polyolefin resin film of the present invention. The bag is formed by a known molding method, for example, a method in which a tube-shaped film molded by an inflation molding method is heat-sealed in a direction (TD direction) perpendicular to the take-up direction (MD direction), T-die cast film molding method It is manufactured by a method of stacking two sheets of film formed in the above and sealing all sides.

  The polyolefin-based resin film and bag of the present invention are excellent in slipperiness and transparency. Therefore, the polyolefin resin film and the bag are suitable for packaging of products that require visibility of the contents, or packaging that requires high slipperiness such as using an automatic packaging machine. Are preferably used. In addition, since the amount of lubricant can be reduced or added compared to conventional products, it can be used in applications that require a high level of transfer of additives to contents, such as electronic component packaging, medical device packaging, and masking film. Preferably used.

Hereinafter, the present invention will be described with reference to examples and comparative examples.
The physical properties in Examples and Comparative Examples were measured according to the following methods.
I. Properties of polymer (1) Melt flow rate (MFR, unit: g / 10 min)
According to the method defined in JIS K7210, the measurement was performed under the conditions of a load of 21.18 N and a temperature of 190 ° C.

(2) Melt flow rate ratio (MFRR)
According to the method defined in JIS K7210, the value obtained by dividing the melt flow rate measured under the conditions of a load of 211.8 N and a temperature of 190 ° C. by the melt flow rate measured under the conditions of a load of 21.18 N and a temperature of 190 ° C. is MFRR. did.

(3) Density (Unit: Kg / m ³ )
It measured according to the method prescribed | regulated to A method among JISK7112. The sample was annealed according to JIS K6760.

(4) Molecular weight distribution (Mz / Mw, Mw / Mn)
Using gel permeation chromatography (GPC) method, the number average molecular weight (Mn), weight average molecular weight (Mw) and Z average molecular weight (Mz) are measured under the following conditions (1) to (7). As the molecular weight distribution, the ratio of the Z average molecular weight to the weight average molecular weight (Mz / Mw) and the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) were determined.
(1) Equipment: 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
(7) Detector: Differential refraction

(5) Flow activation energy (Ea, unit: kJ / mol)
Using a viscoelasticity measuring device (Rheometrics Mechanical Spectrometer RMS-800 manufactured by Rheometrics), a melt complex viscosity-angular frequency curve at 130 ° C., 150 ° C., 170 ° C. and 190 ° C. was measured under the following measurement conditions. From the obtained melt complex viscosity-angular frequency curve, calculation software Rhios V. The activation energy (Ea) was determined using 4.4.4.
<Measurement conditions>
Geometry: Parallel plate Plate diameter: 25mm
Plate spacing: 1.5-2mm
Strain: 5%
Angular frequency: 0.1 to 100 rad / sec Measurement atmosphere: Under nitrogen

(6) Melt complex viscosity (η *, unit: Pa · s)
From the melt viscoelasticity at 190 ° C. measured in the above (5), the melt viscosity at 190 ° C. at an angular frequency of 100 rad / sec was determined.

(7) Melt tension (MT, unit: cN)
Using a melt tension tester manufactured by Toyo Seiki Seisakusho, a molten resin filled in a 9.5 mmφ barrel at a temperature of 190 ° C., a piston descending speed of 5.5 mm / min, a diameter of 2.09 mmφ, and a length of 8 mm The melted resin extruded from the orifice was wound up at a winding speed of 40 rpm / min using a winding roll having a diameter of 150 mmφ, and the tension value immediately before the molten resin broke was measured. It shows that melt tension is so large that this value is large.

(8) Intrinsic viscosity ([η], unit: dl / g)
A tetralin solution (hereinafter referred to as a blank solution) in which 5% by weight of 2,6-di-t-butyl-p-cresol (BHT) is dissolved, and the concentration of the ethylene polymer resin with respect to the blank solution is 1 mg. / Ml tetralin solution at 135 ° C. (hereinafter referred to as sample solution).
), And by measuring the drop time of the blank solution and the sample solution at 135 ° C. with an Ubbelohde viscometer, and determining the relative viscosity (ηrel) at 135 ° C. from the drop time, Calculated from
[Η] = 23.3 × log (ηrel)

II. Physical properties of film (9) HAZE (unit:%)
The method specified in ASTM D1003 was followed. It shows that transparency is excellent, so that this value is small.

(10) Gloss (unit:%)
The 45 ° specular gloss measurement method defined in JIS Z 8741 was followed. The larger this value, the better the gloss.

(11) Sliding property (static friction coefficient μs, dynamic friction coefficient μk)
Using an AB-401 type friction coefficient measuring device manufactured by Tester Sangyo Co., Ltd., measurement was performed according to JIS K7125-1987, except that the 70 mm sliding plate was moved under the condition of a thread weighing 500 g and a sliding speed of 700 mm / min. The smaller this value, the better the slipperiness.

III. Measurement of surface roughness of film (1) Measurement of surface roughness curve A surface roughness curve was measured under the following conditions.
Apparatus: Scanning probe microscope (Digital Instruments Large sample observation apparatus D-3000 type) Scanning mode: Tapping mode Probe: Silicon single crystal (NanoWorld NCHR-W)
Probe frequency: The values listed in Table 2 were used.
Scanning range: 100 μm × 100 μm, 10 μm × 10 μm
Scanning speed: 0.5 Hz (when scanning range is 100 μm × 100 μm)
1 Hz (when scanning range is 10 μm × 10 μm)
Setpoint ratio: The values listed in Table 2 were used.
Measurement environment: room temperature, air,
Observation image: Height image Number of pixels: 512 × 512 pixels The sample was previously cleaned with acetone to remove surface stains, cut out to about 1 cm × 1 cm, and then fixed on a metal sample table with an adhesive. . The sample table on which the sample was fixed was fixed to a metal chuck with a magnet, and the chuck was fixed to the granite base of the measurement unit by suction with a vacuum pump. In addition, the charge of the sample was removed by a static electricity removal blower (Static Wiper Dynac PB160M manufactured by Fiesa) before measurement.
The measurement unit is installed on a vibration isolation table (Digital Instruments VT-103-3K) equipped with a soundproof cover that can be sealed to eliminate the influence of vibration and noise from the floor. Sealed. Using a standard sample for noise floor measurement (a silicon wafer manufactured by Veeco Japan), a height image is measured under the following conditions, and an off line analysis function of a controller for a scanning probe microscope (Digital Instruments NanoScope IIIa) When the standard deviation value (RMS value) of the noise height was determined by the Roughness analysis function, it was 0.055 nm or less.
Scanning mode: Tapping mode Probe: Silicon single crystal (NanoWorld NCHR-W)
Probe frequency: 256.7 kHz
Scanning range: 1 nm x 1 nm
Scan speed: 10Hz and 2.44Hz
Setpoint ratio: 0.87 (when scanning speed is 10 Hz)
0.85 (when scanning speed is 2.44 Hz)
Measurement environment: room temperature, in the air Observation image: height image Number of pixels: 512 × 512 pixels

(2) Calculation of surface roughness strength (0.4 to 20 μm) “Flatten” function of scanning probe microscope controller (Digital Instruments III Nanoscope IIIa) is obtained by measuring the surface roughness curve obtained by measurement in a scanning range of 100 μm × 100 μm. Was used to correct the inclination of the height image obtained by the scanning probe microscope with Flatten Order 1. Next, using the “Power Spectral Density” function, the square value of the amplitude of each basic curve was determined for the basic curve having a wavelength of 100 μm to 0.391 μm. From the square value, the _{ratio of} the surface roughness strength I _0.4-20 , the surface roughness strength I _0.4-2 , and the surface roughness strength I _0.4-2 in the surface roughness strength I _0.4-20 was calculated.

(3) Calculation of surface roughness strength (0.1 to 2.0 μm) A surface roughness curve obtained by measurement in a scanning range of 10 μm × 10 μm is obtained by using “Flatten” of a controller for scanning probe microscope (Digital Instruments IIIA, NanoScope IIIa). Using the function, the inclination of the height image obtained by the scanning probe microscope was corrected with Flatten Order 1. Next, using the “Power Spectral Density” function, the square value of the amplitude of each basic curve was determined for the basic curve having a wavelength of 10 μm to 0.0391 μm. From the square value, the ratio of the surface roughness strength _I0.1-2 , the surface roughness strength _I0.1-1 and the surface roughness strength _I0.1-1 in the surface roughness strength _I0.1-2 was calculated.

Example 1
(1) Preparation of promoter support In the same manner as the synthesis of component (A) described in Example 10 (1) and (2) of JP-A No. 2003-171415, a solid product (hereinafter referred to as a solid product) is prepared. (Referred to as (a)).

(2) Prepolymerization In an autoclave with a stirrer having an internal volume of 210 liters, which was previously purged with nitrogen, 0.7 kg of the above solid product (a), 100 liters of butane, 0.02 kg of 1-butene, 12 hydrogen as normal temperature and normal pressure After charging the liter, the autoclave was heated to 42 ° C. Further, ethylene was charged by 0.1 MPa as the gas phase pressure in the autoclave, and after the system was stabilized, 225 mmol of triisobutylaluminum and 75 mmol of racemic-ethylenebis (1-indenyl) zirconium diphenoxide were added to initiate polymerization. . While raising the temperature to 50 ° C. and continuously supplying ethylene and hydrogen, preliminary polymerization was carried out at 50 ° C. for a total of 6 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 per 1 g of the solid product (a) was prepolymerized. A prepolymerized catalyst component was obtained.

(3) Continuous gas phase polymerization Using a continuous fluidized bed gas phase polymerization apparatus, the polymerization temperature is 85 ° C., the polymerization pressure is 2 MPa, and the above prepolymerization catalyst component, triisobutylaluminum, ethylene, 1-butene and hydrogen are reacted. The reactor was continuously fed into the reactor, and the molar ratio of hydrogen to ethylene in the reaction gas was 1.8%, the molar ratio of 1-butene to ethylene was 3%, and the average polymerization time was 5 hr. Butene copolymerization was carried out. By polymerization, a powder of an ethylene-1-butene copolymer (hereinafter referred to as PE-1) was obtained.

(4) Granulation of ethylene-1-butene copolymer powder Using the LCM50 extruder manufactured by Kobe Steel, the PE-1 powder obtained above was fed at a feed rate of 50 kg / hr, a screw rotation speed of 450 rpm, and a gate. By granulating under the conditions of an opening degree of 50%, a suction pressure of 0.1 MPa, and a resin temperature of 200 to 215 ° C., PE-1 pellets were obtained. The physical properties of the obtained PE-1 pellets are shown in Table 1.

(5) Film processing Using the above-mentioned granulated pellets as a sample, Placo, 30 mmφ, L / D = 28, full flight type screw single screw extruder, 50 mmφ, lip gap 0.8 mm die, double slit air Using a ring, a film with a thickness of 50 μm was obtained by forming a film under conditions of a processing temperature of 170 ° C., an extrusion rate of 5.5 kg / hr, a frost line distance (FLD) of 200 mm, and a blow ratio of 1.8. Table 2 shows the physical property evaluation results of the obtained film.

Comparative Example 1
Further, 1-hexene was continuously fed into the reactor, the molar ratio of hydrogen to ethylene in the reaction gas was 1.4%, and the total molar ratio of 1-butene and 1-hexene to ethylene was 2. Polymerization was carried out according to (3) of Example 1 except that 7%, the molar ratio of 1-butene to 1-hexene was 8: 1, and the polymerization temperature was 75 ° C. Copolymerization with ethylene-1-hexene-1-butene A powder of a polymer (hereinafter referred to as PE-2) was obtained.

750 ppm of an antioxidant (Sumitomo Chemical Co., Ltd., Sumilizer GP) was added to the PE-2 powder, and granulated according to (4) of Example 1 to obtain PE-2 pellets. The physical properties of the obtained PE-2 pellets are shown in Table 1.
Next, film processing using the obtained PE-2 pellets was performed according to (1) of Example 1. The physical property evaluation results of the obtained PE-2 film are shown in Table 2.

Comparative Example 2
Using 100 parts by weight of a commercially available polyethylene resin (manufactured by Sumitomo Chemical Co., Ltd., high-pressure method low-density polyethylene F238-1; hereinafter referred to as PE-3), the inflation film processing was performed according to (5) of Example 1. The film of PE-3 was obtained. The physical properties of PE-3 are shown in Table 1, and the physical properties evaluation results of the obtained film are shown in Table 2.

Comparative Example 3
Using 100 parts by weight of a commercially available polyethylene resin (manufactured by Sumitomo Chemical Co., Ltd., high-pressure method low-density polyethylene F101-1; hereinafter referred to as PE-4), an inflation film is processed according to (5) of Example 1. And PE-4 film was obtained. The physical properties of PE-4 are shown in Table 1, and the physical properties evaluation results of the obtained film are shown in Table 2.

Claims (5)

  An ethylene-α-olefin copolymer having a monomer unit based on ethylene and a monomer unit based on an α-olefin having 3 to 20 carbon atoms, and having a flow activation energy (Ea) of 35 kJ / The molecular weight distribution (Mz / Mw) represented by the ratio of the Z average molecular weight (Mz) and the weight average molecular weight (Mw) is 3.4 or more. A polyolefin-based resin film having a layer containing an ethylene-α-olefin copolymer of at least one surface. The polyolefin resin film according to claim 1 , wherein the ethylene-α-olefin copolymer is a copolymer satisfying the following formula (1).
η * <1550 × MFR ^−0.25 −420 Formula (1)
η *: Melt complex viscosity at a temperature of 190 ° C. and an angular frequency of 100 rad / sec
(Unit: Pa · sec)
MFR: Temperature 190 ° C., load 21.18 N as defined in JIS K7210
Melt flow rate measured under the conditions (unit: g / 10 min) The weight average molecular weight (Mw) to number average molecular weight (Mn) of the molecular weight distribution of the ethylene -α- olefin copolymer represented by ratio (Mw / Mn) according to claim 1 or 2 which is 5 to 30 Polyolefin resin film. The polyolefin resin film according to any one of claims 1 to 3 , wherein the ethylene-α-olefin copolymer is a copolymer satisfying the following formulas (2) and (3).
2 x MFR ^-0.59 <MT <40 x MFR ^-0.59 Formula (2)
1.02 × MFR ^−0.094 <[η] <1.50 × MFR ^−0.156 Formula (3)
MFR: Temperature 190 ° C., load 21.18 N as defined in JIS K7210
Melt flow rate measured under the conditions (unit: g / 10 min)
MT: melt tension at 190 ° C. (unit: cN)
[Η]: Intrinsic viscosity (unit: dl / g) The bag which uses the polyolefin resin film in any one of Claims 1-4 .