JP2006299167A - Inflation film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inflation film which has good bubble stability, even when formed in a high blow ratio, is free from wrinkles and sagging, and little produces deposits and powder, even when formed for a long time. <P>SOLUTION: This inflation film is characterized by comprising a polyethylene-based resin satisfying the following requirements (A) to (E). (A) A density is 935 to 980 kg/m<SP>3</SP>. (B) MFR (g/10 min) is 0.01 to 0.5. (C) The number of ≥6C long chain branches is 0.01 to 3 per 1000 carbon atoms. (D) Melt tension (MS<SB>190</SB>)(mN) and MFR (g/10 min, 190°C) satisfy formula (1): MS<SB>190</SB>>22×MFR<SP>-0.88</SP>(1), and melt tension (MS<SB>160</SB>)(mN) and MFR (g/10 min, 190°C) satisfy formula (2): MS<SB>160</SB>>110-110×log(MFR) (2). (E) An elution rate at 0°C by TREF is <0.2 wt.%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inflation film that has good bubble stability during inflation molding, has no wrinkles or slackness in the molded film, and is less likely to cause sag or powder blowing even if molded for a long time.

  Conventionally, a film made of high-density polyethylene resin with blow ratio 3-7 by air-cooled inflation molding method is well-known as balance film because it has a good balance of mechanical strength in the vertical and horizontal directions. It is used for films, curing films, shopping bags, kitchen bags, etc.

  On the other hand, recently, from the viewpoint of environmental issues such as waste reduction, energy saving, and cost reduction, there is an increasing demand for thinning of various films, and there is a tendency to produce high-blow ratio thin films at high speed even in balance film applications. It is in. However, when trying to mold a high-density polyethylene resin used in conventional balance films at a high speed and a high blow ratio by the inflation molding method, fluctuations such as wobbling of the bubbles occur, and the film tends to wrinkle or sag. , Having a problem that a uniform product cannot be obtained.

  Regarding this problem, a resin composition obtained by melt-kneading a resin composition comprising a specific low molecular weight high density polyethylene and a specific high molecular weight high density polyethylene and a radical generator in a specific oxygen concentration atmosphere, It is disclosed that there is no problem in the physical properties of the film and that stable high-speed film formation is possible (see, for example, Patent Document 1).

  In order to increase the productivity and yield of the film, it is preferable to be able to continuously produce for a long time, but the high-density polyethylene resin that has been used for conventional balance films has a lot of damage in the die lip due to the continuous production for a long time. Thus, there is a problem that continuous production for a long time is restricted such that the film is broken or a large amount of powder generated from the film adheres to the guide plate above the molding machine to contaminate the product film.

  Concerning this problem, the addition of specific amounts of specific fluorine processing agents, phenolic antioxidants, and phosphorus antioxidants to specific high-density polyethylene prevents the occurrence of scum and continues stably for a long time. It is disclosed that film formation becomes possible (for example, refer to Patent Document 2).

JP-A-8-208898 JP-A-9-255820

  However, since the resin composition disclosed in Patent Document 1 is a blend of resins having greatly different molecular weights, complete dispersion and mixing are difficult even by melt-kneading, and the mixing of the two is insufficient. There is a problem that fish eyes are easily generated on the film. The generation of this fish eye becomes more remarkable by using a radical generator, combined with insufficient mixing of the resins. In addition, blending with low molecular weight resins is effective for improving processability such as reducing extrusion load, but on the other hand, there is a problem that continuous production for a long time cannot be achieved due to an increase in blown-off and powder blowing during inflation molding. .

  On the other hand, the resin composition disclosed in Patent Document 2 contains a specific antioxidant to suppress the generation of a resin degradation product and to prevent the resin degradation product from accumulating on a die lip with a fluorine-based processing agent. However, it is difficult to uniformly disperse the fluorine-based processing agent in the resin, and there is a problem in that the effect of preventing sag varies greatly depending on the dispersion state.

  Accordingly, the object of the present invention is to provide an inflation film that has good bubble stability at the time of inflation molding, has no wrinkles or sag in the molded film, and is less likely to cause scumming or powder blowing even if molded for a long time. To do.

  As a result of intensive studies on the above problems, the present inventors have used a polyethylene-based resin that satisfies specific requirements, resulting in better bubble stability during inflation molding than when a conventional polyethylene resin is used. Thus, the present inventors have found that an inflation film that does not cause wrinkles or sag in a molded film and that does not generate sag or powder blow even if molded for a long time is obtained, and the present invention has been completed.

That is, this invention relates to the inflation film characterized by consisting of the polyethylene-type resin which satisfy | fills the requirements of following (A)-(E).
(A) The density is 935 kg / m ³ or more and 980 kg / m ³ or less,
(B) MFR (g / 10 min) at 190 ° C. and 2.16 kg load is 0.01 or more and 0.5 or less,
(C) The number of long chain branches having 6 or more carbon atoms is 0.01 to 3 per 1,000 carbon atoms,
(D) Melt tension (MS ₁₉₀ ) (mN) measured at 190 ° C. and MFR (g / 10 min, 190 ° C.) with a load of 2.16 kg are represented by the following formula (1)
MS ₁₉₀ > 22 × MFR ^−0.88 (1)
The melt tension (MS ₁₆₀ ) (mN) measured at 160 ° C. and the MFR (g / 10 min, 190 ° C.) with a load of 2.16 kg satisfy the following formula (2),
MS ₁₆₀ > 110-110 × log (MFR) (2)
(E) The elution ratio at 0 ° C. by temperature rising elution fractionation (TREF) is less than 0.2% by weight. Hereinafter, the present invention will be described in detail.

The density of the polyethylene resin used in the inflation film of the present invention is preferably 935 kg / m ³ or more and 980 kg / m ³ or less as a value measured by a density gradient tube method in accordance with JIS K6922-1 (1997). is less 940 kg / ^{m 3} or more 970 kg / ^{m 3,} more preferably not more than 945 kg / ^{m 3} or more 960 kg / ^{m 3.} If the density is less than 935 kg / m ³ , the resulting inflation film may have insufficient rigidity, and if it exceeds 0.980 g / cm ³ , the impact strength may be insufficient.

The weight average molecular weight (M _w ) in terms of linear polyethylene of the polyethylene resin used in the inflation film of the present invention is 10,000 or more and 1,000,000 or less, preferably 20,000 or more and 700,000. Or less, more preferably 25,000 or more and 300,000 or less. If _Mw is less than 10,000 or exceeds 1,000,000, it is difficult to perform inflation molding.

  The MFR at 190 ° C. and a load of 2.16 kg of the polyethylene resin used for the inflation film of the present invention is 0.01 to 0.5 g / 10 minutes, preferably 0.02 to 0.3 g / 10 minutes, more preferably Is 0.03 to 0.1 g / 10 min. If it is less than 0.01 g / 10 minutes or more than 0.5 g / 10 minutes, it is difficult to perform inflation molding.

The number of long chain branches of the polyethylene resin used in the inflation film of the present invention is 0.01 or more and 3 or less per 1,000 carbon atoms. If the number is less than 0.01, when performing inflation molding at a high blow ratio, the bubbles become unstable and wrinkles and slack are likely to occur in the bubbles. If the number exceeds 3, the resulting blown film may be inferior in mechanical properties. The number of long-chain branches is the number of branches of hexyl groups or more (6 or more carbon atoms) detected by ¹³ C-NMR measurement.

The melt tension (MS ₁₉₀ ) (mN) measured at 190 ° C. and the MFR (g / 10 min, 190 ° C.) with a load of 2.16 kg of the polyethylene resin used in the inflation film of the present invention are expressed by the following formula (1).
MS ₁₉₀ > 22 × MFR ^−0.88 (1)
Preferably, the following formula (1) ′
MS ₁₉₀ > 30 × MFR− ^0.88 (1) ′
More preferably, the following formula (1) "
MS ₁₉₀ > 5 + 30 × MFR ^−0.88 (1) ”
It is in the relationship shown by. When the formula (1) is not satisfied, when performing inflation molding at a high blow ratio, the bubble becomes unstable and wrinkles and slack easily occur in the bubble.

Further, the melt tension (MS ₁₆₀ ) (mN) measured at 160 ° C. and the MFR (g / 10 min, 190 ° C.) of 2.16 kg load of the polyethylene resin used for the inflation film of the present invention are expressed by the following formula ( 2)
MS ₁₆₀ > 110-110 × log (MFR) (2)
Preferably, the following formula (2) ′
MS ₁₆₀ > 130-110 × log (MFR) (2) ′
More preferably, the following formula (2) "
MS ₁₆₀ > 150-110 × log (MFR) (2) ”
It is in the relationship shown by. When the expression (2) is not satisfied, when inflation molding is performed at a high blow ratio, the bubble becomes unstable and wrinkles and slack are likely to occur in the bubble.

  The polyethylene resin used in the inflation film of the present invention has an elution ratio at 0 ° C. of less than 0.2% by weight, preferably less than 0.1% by weight, and more preferably measured using temperature rising elution fractionation (TREF). Is less than 0.05% by weight. When the elution ratio at 0 ° C. is 0.2% by weight or more, there is a possibility that the continuous production for a long time may be difficult due to the occurrence of scouring and powder blowing during inflation molding.

The polyethylene resin used in the inflation film of the present invention has a shrinkage factor (g ′ value) of 0.1 or more and less than 0.9 as evaluated by gel permeation chromatography (GPC) / intrinsic viscometer, It is preferable that it is 0.1 or more and 0.7 or less, and this improves the stability of the bubble and the uniformity of the film during the inflation molding. The shrinkage factor (g ′ value) in the present invention is a parameter representing the degree of long-chain branching, the intrinsic viscosity of the polyethylene-based resin of the present invention at an absolute molecular weight three times the weight average molecular weight (M _w ), and the branching. It is a ratio with the intrinsic viscosity at the same molecular weight of high-density polyethylene (hereinafter abbreviated as HDPE) that does not have any. Further, the relationship between the g ′ value and the contraction factor (g value) evaluated by the GPC / light scatterometer is preferably the formula (3), more preferably the formula (3) ′. As a result, bubble stability and film uniformity when the polyethylene resin of the present invention is blown are further improved. The g value is a ratio of the mean square of the inertia radius of the polyethylene resin of the present invention at an absolute molecular weight three times _Mw and the mean square of the inertia radius at the same molecular weight of HDPE having no branching.

0.2 <log (g ′) / log (g) <1.3 (3)
0.5 <log (g ′) / log (g) <1.0 (3) ′
Further, between the g value in an absolute molecular weight three times the _{M w (g 3M)} and g values of the absolute molecular weight of 1 × _{M w (g M),} formula (4), preferably of formula (4) ' More preferably, the relationship represented by the formula (4) "is desirable in order to improve the stability of bubbles and make the film uniform when the polyethylene resin of the present invention is blown.

0 <g _3M / g _M ≦ 1 (4)
0 <g _3M / g _M ≦ 0.9 (4) ′
0 <g _3M / g _M ≦ 0.8 (4) ”
The polyethylene resin used in the inflation film of the present invention is an ethylene polymer having a vinyl group at the terminal obtained by polymerizing ethylene, or a terminal obtained by copolymerizing ethylene and an olefin having 3 or more carbon atoms. Is an ethylene copolymer having a vinyl group,
(F) M _n is 2,000 or more,
(G) It is desirable to be obtained by polymerizing ethylene and optionally an olefin having 3 or more carbon atoms in the presence of a macromonomer having M _w / M _n of 2 or more and 5 or less. The macromonomer is an olefin polymer having a vinyl group at the terminal, preferably an ethylene polymer having a vinyl group at the terminal obtained by polymerizing ethylene, or copolymerizing ethylene and an olefin having 3 or more carbon atoms. Is an ethylene copolymer having a vinyl group at the terminal, and more preferably a long chain branch (i.e., ¹³ C-NMR) among branches other than those derived from olefins having 3 or more carbon atoms, which are optionally used. Linear ethylene polymer or linear ethylene copolymer having a vinyl group at the terminal, wherein the number of branches of hexyl groups detected by measurement is less than 0.01 per 1,000 main chain methylene carbons It is.

  Examples of the olefin having 3 or more carbon atoms include propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, α-olefin such as vinylcycloalkane, norbornene, Examples include cyclic olefins such as norbornadiene, dienes such as butadiene or 1,4-hexadiene, and styrene. Two or more of these olefins can be mixed and used.

When an ethylene polymer having a vinyl group at the terminal or an ethylene copolymer having a vinyl group at the terminal is used as the macromonomer, the linear polyethylene equivalent number average molecular weight (M _n ) is 2,000 or more. , Preferably it is 3,000 or more, More preferably, it is 5,000 or more. The weight average molecular weight (M _w ) in terms of linear polyethylene is 3,000 or more, preferably 5,000 or more, and more preferably greater than 10,000. The ratio of the weight average molecular weight (M _w ) to M _n (M _w / M _n ) is 2 or more and 5 or less, preferably 2 or more and 4 or less, more preferably 2 or more and 3.5 or less. . The following general formula (5)
Z = [X / (X + Y)] × 2 (5)
(Where X is the number of vinyl ends per 1,000 main chain methylene carbons of the macromonomer, and Y is the number of saturated ends per 1,000 main chain methylene carbons of the macromonomer.)
The ratio (Z) between the number of vinyl ends and the number of saturated ends represented by is from 0.25 to 1, preferably from 0.50 to 1. X and Y are determined by ¹ H-NMR, ¹³ C-NMR, FT-IR, or the like. For example, in ¹³ C-NMR, the presence and amount of vinyl end can be confirmed by peaks at 114 ppm and 139 ppm at the vinyl end and 32.3 ppm, 22.9 ppm and 14.1 ppm at the saturated end.

  The production method of the macromonomer in the present invention is not particularly limited, but when producing an ethylene polymer having a vinyl group at the terminal or an ethylene copolymer having a vinyl group at the terminal as the macromonomer, for example, Group 3 of the periodic table A method of polymerizing ethylene using a catalyst containing a metallocene compound containing a transition metal selected from Group 4, Group 5 and Group 6 as a main component can be used. Examples of the cocatalyst include organoaluminum compounds, proton acid salts, Lewis acid salts, metal salts, Lewis acids and clay minerals.

  The polyethylene resin constituting the inflation film of the present invention uses, for example, a catalyst containing as a main component a metallocene compound containing a transition metal selected from Group 3, Group 4, Group 5 and Group 6 of the periodic table. Obtained by polymerizing ethylene and optionally an olefin having 3 or more carbon atoms in the presence of a macromonomer. Moreover, a cocatalyst can be used similarly to manufacture of a macromonomer.

  The polymerization temperature is in the range of -70 to 300 ° C, preferably 0 to 250 ° C, more preferably 20 to 150 ° C. The ethylene partial pressure is in the range of 0.001 to 300 MPa, preferably 0.005 to 50 MPa, and more preferably 0.01 to 10 MPa. Further, hydrogen may be present as a molecular weight regulator in the polymerization system.

  In the present invention, when ethylene and an olefin having 3 or more carbon atoms are polymerized in the presence of a macromonomer, the ethylene / olefin having 3 or more carbon atoms (molar ratio) is 1 to 200, preferably 3 to 100, and more preferably. 5 to 50 can be used.

  In the polyethylene resin used for the inflation film of the present invention, an antioxidant, an anti-aging agent, a heat stabilizer, a weather resistance stabilizer, an ultraviolet absorber, a chlorine absorber, Additives such as antistatic agents, antifogging agents, slip agents, lubricants, antiblocking agents, nucleating agents, pigments, dyes, plasticizers, flame retardants, inorganic fillers and organic fillers are blended as necessary. Also good.

  The polyethylene resin used in the inflation film of the present invention is a high-density polyethylene, high-pressure method low-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymer rubber, It can also be used by mixing with other thermoplastic resins such as -1-butene.

The blown film of the present invention can be molded using a known method. For example, the film can be obtained by an air-cooled inflation molding method, a water-cooled inflation molding method, etc., among which the air-cooled inflation molding method is particularly preferable.
Although there is no restriction | limiting in particular in the processing temperature at the time of shape | molding the inflation film of this invention, The range of 150-250 degreeC is preferable from being able to perform the stable shaping | molding process.

  The blow ratio at the time of forming the blown film of the present invention varies depending on the purpose of use of the film, but in order to obtain a film having a good balance of mechanical strength in the vertical and horizontal directions, the blow ratio is set to 3.0 or more. It is preferable to do.

  The thickness of the inflation film of the present invention varies depending on the purpose of use of the film, but is preferably in the range of 5 μm or more and 50 μm or less from the viewpoint of economy and workability.

  The inflation film of the present invention is used, for example, as a masking film for coating, a curing film, a shopping bag, a garbage bag, a kitchen bag, a moisture-proof film for heat insulation in a house, a film for vapor deposition, various packaging films, and a paper bag. It can be suitably used for bags, various agricultural films and the like.

  The inflation film of the present invention has good bubble stability at the time of inflation molding even at a high blow ratio, and there is no wrinkle or slack in the molded film. Therefore, it is useful as a masking film for coating, a curing film, a shopping bag, a kitchen bag, and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

  Preparation of modified hectorite, preparation of a catalyst for producing a macromonomer, production of a macromonomer, production of polyethylene and solvent purification were all carried out under an inert gas atmosphere. As the preparation of modified hectorite, the preparation of a catalyst for producing a macromonomer, the production of a macromonomer, the solvent used for the production of polyethylene, all of the solvents previously purified, dried and deoxygenated in a known manner were used. Diphenylsilanediylbis (cyclopentadienyl) zirconium dichloride, dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride, diphenylmethylene (1-cyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) ) Zirconium dichloride was synthesized and identified by a known method. A hexane solution (0.714M) of triisobutylaluminum was manufactured by Tosoh Finechem Corporation.

  Furthermore, various physical properties of the polyethylene resins in Examples and Comparative Examples were measured by the methods shown below.

-Molecular weight and molecular weight distribution-
The weight average molecular weight (M _w ) and number average molecular weight (M _n ) were measured by gel permeation chromatography (GPC). Tosoh Co., Ltd. HLC-8121GPC / HT is used as the GPC device, Tosoh Co., Ltd. TSKgel GMHhr-H (20) HT is used as the column, the column temperature is set to 140 ° C., and 1 is used as the eluent. The measurement was performed using 2,4-trichlorobenzene. A measurement sample was prepared at a concentration of 1.0 mg / mL, and 0.3 mL was injected and measured. The calibration curve of molecular weight is calibrated using a polystyrene sample having a known molecular weight. In addition, _Mw and _Mn were calculated | required as a value of linear polyethylene conversion.

-Contraction factor (g 'value)-
The shrinkage factor (g ′ value) is the [η] at 3 times the absolute molecular weight of _Mw determined by the method of measuring [η] of polyethylene resin fractionated by GPC, at the same molecular weight of HDPE without any branching. The value divided by [η]. Tosoh Co., Ltd. HLC-8121GPC / HT is used as the GPC apparatus, Tosoh Co., Ltd. TSKgel GMHhr-H (20) HT is used as the column, the column temperature is set to 145 ° C., and 1 is used as the eluent. Measurement was performed using 2,4-trichlorobenzene. A measurement sample was prepared at a concentration of 2.0 mg / mL, and 0.3 mL was injected and measured. As a viscometer, a capillary differential pressure viscometer 210R + manufactured by Viscotek was used.

~ Shrink factor (g value) ~
The shrinkage factor (g value) was determined by a method of measuring the radius of inertia of a polyethylene resin fractionated by GPC by light scattering. This is a value obtained by dividing the root mean square of the radius of inertia at an absolute molecular weight 3 times _Mw of the polyethylene resin used in the resin cap of the present invention by the root mean square of the same molecular weight of HDPE having no branches. As the light scattering detector, a multi-angle light scattering detector DAWV EOS manufactured by Wyatt Technology was used, and the wavelength of 690 nm was 29.5 °, 33.3 °, 39.0 °, 44.8 °, 50.7. °, 57.5 °, 64.4 °, 72.3 °, 81.1 °, 90.0 °, 98.9 °, 107.7 °, 116.6 °, 125.4 °, 133.2 Measurements were made at detection angles of °, 140.0 °, and 145.8 °.

~ Z value ~
The terminal structure of a macromonomer such as a vinyl terminal or a saturated terminal was measured by ¹³ C-NMR using a JNM-ECA400 type nuclear magnetic resonance apparatus manufactured by JEOL Ltd. The solvent is tetrachloroethane -d _2. The number of vinyl ends was determined from the average value of peaks at 114 ppm and 139 ppm as the number per 1,000 main chain methylene carbons (chemical shift: 30 ppm). Similarly, the number of saturated terminals was determined from the average value of peaks at 32.3 ppm, 22.9 ppm, and 14.1 ppm. From this vinyl terminal number (X) and saturated terminal number (Y), Z = [X / (X + Y)] × 2 was determined.

~density~
The density was measured by a density gradient tube method in accordance with JIS K6922-1 (1997).

~ MFR ~
MFR was measured at 190 ° C. under a load of 2.16 kg in accordance with JIS K6922-1 (1997).

~ Number of long chain branches ~
The number of long chain branches of the polyethylene resin was measured by ¹³ C-NMR using a JNM-GSX270 type nuclear magnetic resonance apparatus manufactured by JEOL Ltd.

~ Melting tension (MS) ~
The polyethylene resin used for the measurement of melt tension (MS) is pre-added with 1,500 ppm Irganox 1010 ^TM (manufactured by Ciba Specialty Chemicals) and 1,500 ppm Irgafos 168 ^TM (manufactured by Ciba Specialty Chemicals) as heat stabilizers. Then, using an internal mixer (trade name: Labo Plast Mill, manufactured by Toyo Seiki Seisakusho Co., Ltd.), kneaded for 3 minutes at 190 ° C. and 30 rpm in a nitrogen stream. The melt tension (MS) is a capillary viscometer (Toyo Seiki Seisakusho, trade name: Capillograph) with a barrel diameter of 9.55 mm, a length (L) of 8 mm, a diameter (D) of 2.095 mm, and an inflow angle of 90 °. A die was mounted and measured. For MS, the temperature was set to 160 ° C. or 190 ° C., the piston lowering speed was set to 10 mm / min, the stretch ratio was set to 47, and the load (mN) required for take-up was MS.

~ Elution rate at 0 ℃ by temperature rising elution fractionation (TREF) ~
The elution ratio at 0 ° C. was calculated from the result of measurement under the following conditions using a cross fractionator (trade name CFC T-150A, manufactured by Mitsubishi Chemical Corporation). This cross fractionation device is an on-line connection of a temperature rising elution fractionation (TREF) mechanism that separates samples using the difference in solubility, and a size exclusion chromatograph that further separates the classified segments by molecular size. It is.

Eluent: ODCB (o-dichlorobenzene), sample concentration: 4.0 mg / mL, injection volume: 0.5 mL, flow rate: 1.0 mL / min, coating on TREF column: 0.2 from 140 ° C. to 0 ° C. Hold for 30 minutes after cooling at a rate of 0 ° C./minute, temperature increase program: 0 ° C., 10 ° C., 20 ° C., 30 ° C., 40 ° C., 50 ° C., 55 ° C., 60 ° C., 65 ° C., 70 ° C., 73 ° C., 76 ℃, 78 ℃, 80 ℃, 82 ℃, 84 ℃, 86 ℃, 88 ℃, 90 ℃, 92 ℃, 94 ℃, 96 ℃, 98 ℃, 100 ℃, 102 ℃, 104 ℃, 106 ℃, 108 ℃, 110 ° C, 120 ° C, 140 ° C (31 steps)
The elution ratio at 0 ° C. was calculated as a value obtained by dividing the weight of the eluted component at 0 ° C. measured under the above conditions by the weight of all the eluted components.

~ Film forming method ~
Film formation was performed with an air-cooled inflation molding machine (Placo Co., Ltd., model HD-50). The extruded resin with the cylinder temperature of the extruder held at 200 ° C. was introduced into a circular die (lip clearance 1.2 mm) heated to 200 ° C., the blow ratio was 6.0, the take-up speed was 50 m / min, and the thickness was 6 μm. An air-cooled inflation film was prepared.

-Bubble stability evaluation-
The bubble stability when forming a film based on the above film forming method was visually confirmed.

The criteria for determining bubble stability are shown below.
○: No bubble shake ×: Bubble shake ~ Bubble shape (bubble bubble and slack) evaluation ~
Based on the above film forming method, the bubble shape after 2 hours from the start of forming the film was visually confirmed.

The criteria for bubble shape evaluation are shown below.
○: No wrinkles or slack in the bubble ×: Wrinkles or slack in the bubble ~ Meani evaluation ~
Based on the film forming method described above, the adherence state of the sealant on the die lip part after 2 hours from the start of forming the film was visually confirmed.

The criteria for the evaluation of the Mayani are shown below.
○: No adherence of the sealant on the die lip Δ: Partially adherence of the sealant on the dielip portion ×: Presence of the adherence on the entire surface of the dielip portion -Powder evaluation-
When forming a film based on the above film forming method, black imitation paper is attached to the guide plate at the top of the molding machine, and the powder adheres to the black imitation paper attached to the guide plate after two hours have elapsed from the start of molding. Was confirmed visually.

The evaluation criteria are shown below.
○: No adhesion of powder to black imitation paper Δ; Partial adhesion of powder to black imitation paper ×: Adhesion of powder to the entire black imitation paper Example 1
[Preparation of modified hectorite]
After adding 60 mL of ethanol and 2.0 mL of 37% concentrated hydrochloric acid to 60 mL of water, 6.55 g (0.022 mol) of N, N-dimethyloctadecylamine was added to the resulting solution and heated to 60 ° C. An N, N-dimethyloctadecylamine hydrochloride solution was prepared. To this solution was added 20 g of hectorite. The suspension was stirred at 60 ° C. for 3 hours, the supernatant was removed, and then washed with 1 L of 60 ° C. water. Then, it dried at 60 degreeC and 10 < ^-3 > torr for 24 hours, and the modified | denatured hectorite with an average particle diameter of 5.2 micrometers was obtained by grind | pulverizing with a jet mill. As a result of elemental analysis, the amount of ions per gram of modified hectorite was 0.85 mmol.

[Preparation of catalyst for macromonomer production]
8.0 g of the above modified hectorite is suspended in 29 mL of hexane, 46 mL of hexane solution of triisobutylaluminum (0.714M) is added, and the mixture is stirred for 1 hour at room temperature, whereby contact formation of the modified hectorite and triisobutylaluminum occurs. I got a thing. On the other hand, 151 mg (320 μmol) of diphenylsilanediylbis (cyclopentadienyl) zirconium dichloride dissolved in toluene was added and stirred overnight at room temperature to obtain a catalyst slurry (100 g / L).

[Manufacture of macromonomer]
To a 10 L autoclave, 6,000 mL of hexane and 5.0 mL of a hexane solution of triisobutylaluminum (0.714 mol / L) were introduced, and the internal temperature of the autoclave was raised to 85 ° C. To this autoclave, 0.88 mL of the catalyst slurry was added, and ethylene was introduced until the partial pressure reached 1.2 MPa to initiate polymerization. During the polymerization, ethylene was continuously introduced so that the partial pressure was kept at 1.2 MPa. The polymerization temperature was controlled at 85 ° C. 90 minutes after the start of the polymerization, the internal temperature was lowered to 50 ° C. and the internal pressure of the autoclave was depressurized to 0.1 MPa, and then nitrogen was introduced into the autoclave until the pressure became 0.6 MPa and depressurized. This operation was repeated 5 times. The macromonomer extracted from the autoclave had M _n = 14,400 and M _w / M _n = 3.02, and when the terminal structure of the macromonomer was analyzed by ¹³ C-NMR, the number of vinyl terminals and the number of saturated terminals were determined. The ratio (Z) was Z = 0.65. In ¹³ C-NMR, 0.41 methyl branches per 1,000 carbon atoms and 0.96 ethyl branches per 1,000 carbon atoms were detected. Furthermore, long chain branching was not detected in ¹³ C-NMR.

[Production of polyethylene]
To a 10 L autoclave containing the macromonomer produced above, 1.4 mL of a hexane solution (0.714 mol / L) of triisobutylaluminum and diphenylmethylene (1-cyclopentadienyl) (2,7-di-t-butyl) -9-Fluorenyl) zirconium dichloride 7 μmol was introduced, and the internal temperature of the autoclave was raised to 60 ° C., followed by stirring for 30 minutes. Subsequently, after raising the internal temperature of the autoclave to 90 ° C., an ethylene / hydrogen mixed gas (1,000 ppm of hydrogen) was introduced until the partial pressure became 0.3 MPa to initiate polymerization. During the polymerization, an ethylene / hydrogen mixed gas was continuously introduced so that the partial pressure was maintained at 0.3 MPa. The polymerization temperature was controlled at 90 ° C. After 230 minutes from the start of polymerization, the internal pressure of the autoclave was released, and the contents were suction filtered. After drying, 1,008 g of polymer was obtained. The obtained polyethylene has an MFR of 0.3 g / 10 min, a density of 955 kg / m ³ , M _w of 13.1 × 10 ⁴ , M _w / M _n of 5.7, and the number of long chain branches of 0.03. / 1,000 carbon. Other physical properties are shown in Tables 1-3.

  0.04 parts by weight of Irganox 1076 (manufactured by Ciba Specialty Chemicals) and 0.08 of GSY-P101 (manufactured by API Corporation) are used as antioxidants with respect to 100 parts by weight of the obtained polyethylene powder. 0.04 part by weight of DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.) was blended as a part by weight and a chlorine absorbent, and mixed for 1 minute at 820 rpm by a Henschel mixer (model number FM75C, Mitsui Miike Seisakusho Co., Ltd.). Then, using a 50 mmφ single screw extruder (model number PDA-50 manufactured by Plako), the mixture was kneaded at a set temperature of 200 ° C. and a rotation speed of 100 rpm to form a pellet.

  Using the obtained polyethylene, inflation molding was performed under the conditions described in the film molding method, and bubble stability, bubble shape, meanani and powder blowing were evaluated. The results are shown in Table 4.

Example 2
[Preparation of catalyst for macromonomer production]
Suspend 8.0 g of modified hectorite prepared in Example 1 [Preparation of modified hectorite] in 29 mL of hexane, add 46 mL of hexane solution of triisobutylaluminum (0.714 M), and stir at room temperature for 1 hour. To obtain a contact product of modified hectorite and triisobutylaluminum. On the other hand, 111.5 mg (320 μmol) of dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride dissolved in toluene was added and stirred overnight at room temperature to obtain a catalyst slurry (100 g / L). .

[Manufacture of macromonomer]
To a 10 L autoclave, 6,000 mL of hexane and 12 mL of a hexane solution of triisobutylaluminum (0.714 mol / L) were introduced, and the internal temperature of the autoclave was raised to 85 ° C. To the autoclave, 1.25 mL of the catalyst slurry was added, and ethylene was introduced until the partial pressure reached 1.2 MPa to initiate polymerization. During the polymerization, ethylene was continuously introduced so that the partial pressure was kept at 1.2 MPa. The polymerization temperature was controlled at 85 ° C. 90 minutes after the start of the polymerization, the internal temperature was lowered to 50 ° C. and the internal pressure of the autoclave was depressurized to 0.1 MPa, and then nitrogen was introduced into the autoclave until the pressure became 0.6 MPa and depressurized. This operation was repeated 5 times. The _Mn of the macromonomer extracted from the autoclave is 9,600 and _Mw / _Mn is 2.30. When the terminal structure of the macromonomer is analyzed by ¹³ C-NMR, the number of vinyl terminals and the number of saturated terminals are determined. The ratio (Z) was Z = 0.57. In ¹³ C-NMR, 0.52 methyl branches per 1,000 carbon atoms and 1.22 ethyl branches per 1,000 carbon atoms were detected. Furthermore, long chain branching was not detected in ¹³ C-NMR.

[Production of polyethylene]
To a 10 L autoclave containing the macromonomer produced above, 1.4 mL of a hexane solution (0.714 mol / L) of triisobutylaluminum and diphenylmethylene (1-cyclopentadienyl) (2,7-di-t-butyl) -9-fluorenyl) zirconium dichloride 5 μmol was introduced, the internal temperature of the autoclave was raised to 85 ° C., and then an ethylene / hydrogen mixed gas (1,000 ppm of hydrogen) was introduced until the partial pressure reached 0.6 MPa for polymerization. Started. During the polymerization, an ethylene / hydrogen mixed gas was continuously introduced so that the partial pressure was kept at 0.6 MPa. The polymerization temperature was controlled at 85 ° C. After 90 minutes from the start of polymerization, the internal pressure of the autoclave was released, and the contents were suction filtered. After drying, 1,685 g of polymer was obtained. The obtained polyethylene has an MFR of 0.13 g / 10 min, a density of 965 kg / m ³ , M _w of 17.4 × 10 ⁴ , M _w / M _n of 14.5, and the number of long chain branches of 0.03. / 1,000 carbon. Other physical properties are shown in Tables 1-3.

  Inflation molding was performed by the same method as in Example 1 using the obtained polyethylene, and bubble stability, bubble shape, sag and powder blowing were evaluated. The results are shown in Table 4.

Comparative Example 1
Using a commercially available high-density polyethylene (KEIYO polyethylene F3001Y, manufactured by Keiyo Polyethylene Co., Ltd., MFR = 0.04 g / 10 min, density 950 kg / m ³ ), inflation molding was performed in the same manner as in Example 1, and bubble formation was performed. Stability, bubble shape, sag and powder blowing were evaluated. The results are shown in Table 4. As the bubble was wrinkled and slackened, it was easy to cause sag and powder blowing.

Comparative Example 2
Using a commercially available high-density polyethylene (Hi-Zex 7000F, manufactured by Mitsui Chemicals, MFR = 0.04 g / 10 min, density 952 kg / m ³ ), inflation molding was performed in the same manner as in Example 1, and bubble stability was achieved. Property, bubble shape, sag and powder blowing were evaluated. The results are shown in Table 4. As the bubble was wrinkled and slackened, it was easy to cause sag and powder blowing.

Comparative Example 3
Using commercially available high-density polyethylene (Nipolon Hard 6100A, manufactured by Tosoh Corporation, MFR = 0.35 g / 10 min, density 955 kg / m ³ ), inflation molding was performed in the same manner as in Example 1, and bubble stability was achieved. Evaluation of bubble shape, sag and powder blowing was performed. The results are shown in Table 4, but the bubble stability was poor, bubble wrinkles and slacking occurred, and it was easy for meani and powder blowing to occur.

Claims (4)

An inflation film comprising a polyethylene resin that satisfies the following requirements (A) to (E).
(A) The density is 935 kg / m ³ or more and 980 kg / m ³ or less,
(B) MFR (g / 10 min) at 190 ° C. and 2.16 kg load is 0.01 or more and 0.5 or less,
(C) The number of long chain branches having 6 or more carbon atoms is 0.01 to 3 per 1,000 carbon atoms,
(D) Melt tension (MS ₁₉₀ ) (mN) measured at 190 ° C. and MFR (g / 10 min, 190 ° C.) with a load of 2.16 kg are represented by the following formula (1)
MS ₁₉₀ > 22 × MFR ^−0.88 (1)
The melt tension (MS ₁₆₀ ) (mN) measured at 160 ° C. and the MFR (g / 10 min, 190 ° C.) with a load of 2.16 kg satisfy the following formula (2),
MS ₁₆₀ > 110-110 × log (MFR) (2)
(E) Elution ratio at 0 ° C. by temperature rising elution fractionation (TREF) is less than 0.2 wt% An ethylene polymer having a vinyl group at a terminal obtained by polymerizing ethylene, or an ethylene copolymer having a vinyl group at a terminal obtained by copolymerizing ethylene and an olefin having 3 or more carbon atoms;
(F) M _n is 2,000 or more,
(G) It consists of a polyethylene-based resin obtained by polymerizing ethylene and optionally an olefin having 3 or more carbon atoms in the presence of a macromonomer having M _w / M _n of 2 or more and 5 or less. Item 1. The inflation film according to Item 1. The blown film according to claim 1 or 2, wherein a blow ratio at the time of blow molding is 3.0 or more. The inflation film according to claim 1, wherein the film thickness is 5 μm or more and 50 μm or less.