JPH10330555A - Polyethylene composition for blow molding and blow molding prepared by molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition desirable for the production of blow moldings such as bottles by selecting a composition comprising an ethylene/α-olefin copolymer having a density, a melt flow rate, etc., in specified ranges, a high-density polyethylene and a high-pressure process low-density polyethylene in a specified ratio and having a melt tension of a specified value or above. SOLUTION: There is provided a composition comprising 18-80 wt.% ethylene/α-olefin copolymer (A), 18-80 wt.% high-density polyethylene (B) and 2-40 wt.% high-pressure process low-density polyethylene (C) and having a melt tension of 2.5 g or above at 190 deg.C. Component A has a density of 0.880-0.960, a melt flow rate (at 190 deg.C under a load of 2.16 kg) (MFR2.16 ) of 3-200, an MFR (at 190 deg.C under a load of 10.0 kg) (MFR10.0 )/MFR2.16 ratio of 1-20, and an Mw/Mn ratio of 2.0-4.0, component B has a density of 0.935-0.970, and an MFR2.16 of 0.01-20, and component C has a density of 0.915-0.935 and an MFR2.16 of 0.01-30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene composition for blow molding and a blow molded product obtained by using the same. More particularly, the present invention is suitable for the production of blow molded products such as bottles, The present invention relates to a polyethylene composition having excellent transparency, surface smoothness, chemical resistance, and heat resistance (peelability at high temperatures).

[0002]

2. Description of the Related Art Various hollow containers have been manufactured using a polyolefin resin such as polyethylene or polypropylene as a material for blow molding (hollow molding). For example,
JP-A-7-188777 discloses a polyethylene resin composition for blow molding (hollow molding) containing a specific additive in a mixture of two types of polyethylene having a specific melt flow and a specific density.

JP-A-7-257538 discloses a plastic container blow-molded using a resin obtained by melting and mixing a cyclic polyolefin with polyethylene having a specific melt flow rate. JP-A-7-22
No. 8748 discloses a polypropylene composition for blow molding comprising a specific propylene-ethylene block copolymer and a specific high-density polyethylene.

On the other hand, polyethylene produced from LLDPE obtained using a so-called metallocene compound as a polymerization catalyst has been developed. For example, JP-A-6-136
193, JP-A-6-136198 and JP-A-6-136200 disclose that a polyethylene composition comprising (A) a metallocene-based LLDPE having specific physical properties and (B) a specific crystalline polyolefin is produced as a film. It is disclosed that it is suitable for.

As the physical properties of the metallocene-based LLDPE as the component (A) of these compositions, the above publication discloses density, melt flow rate (MFR), the relationship between DSC endothermic peak temperature and density, and the relationship between MFR and melt tension. Specific ranges, such as relationships, liquidity indexes, swell ratios, etc., are described. Although the use of these compositions is described as being applicable to blow molding other than the above-mentioned films, there is no specific description of suitable properties and examples relating to blow molding.

In order to produce a molded product such as a bottle by blow molding, conventionally known polyethylene compositions for blow molding require molding, transparency, surface smoothness and chemical resistance in blow molding. In some cases, the balance between heat resistance and heat resistance (peelability at high temperatures) was not always excellent. In particular, in the case of the direct blow method as the blow molding method, it was sometimes difficult to mold with a polyethylene-based material.

[0007]

The present invention is suitable for the production of blow-molded articles such as bottles, and is particularly suitable for transparency, moldability, surface smoothness, chemical resistance, heat resistance (exfoliation at high temperatures). And a blow-molded article using the same.

[0008]

According to the present invention, there are provided (A) 18 to 80% by weight of an ethylene-α-olefin copolymer, and (B)
190 ° C. consisting of 18 to 80% by weight of high-density polyethylene and (C) 2 to 40% by weight of high-pressure low-density polyethylene
Is a polyethylene composition having a melt tension of 2.5 g or more, wherein the (A) ethylene-α-olefin copolymer, the (B) high-density polyethylene, and the (C) high-pressure low-density polyethylene are respectively as follows: The present invention relates to a blow molding polyethylene composition having the following characteristics:

(A) Ethylene-α-olefin copolymer
Body: (A-1) Density (d) = 0.880 to 0.960 (g /
cm^Three(A-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 3 to 200 (g / 10
(A-3) Melt at 190 ° C. and 10.0 kg load
Flow rate (MFR _10.0) And 190 ° C, 2.16 Kg
Melt flow rate under load (MFR_2.16) And ratio
 (MFR_10.0) / (MFR_2.16) = 1 to 20 (A-4) Molecular weight distribution (Mw / Mn) = 2.0 to 4.0 (B) High-density polyethylene (provided that the (A) ethylene
(Excluding -α-olefin copolymer): (B-1) Density (d) = 0.935 exceeding 0.935
Below (g / cm^Three(B-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 0.01-20 (g / 1
0 minutes) (C) High-pressure low-density polyethylene (provided that (A)
(Excluding the Tylene-α-olefin copolymer): (C-1) Density (d) = 0.915 to 0.935 (g /
cm^Three(C-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 0.01 to 30 (g / 1
0 minutes)

[0010] The present invention relates to a blow molding polyethylene composition, wherein the polyethylene composition has a critical shear rate at 190 ° C of 400 / sec or more.

Further, the present invention relates to a blow-molded article formed by using the above-mentioned polyethylene composition.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene-α-olefin copolymer which is the component (A) of the blow molding polyethylene composition of the present invention has the following specific properties.

(A) Ethylene-α-olefin copolymer
Body: (A-1) Density (d) = 0.880 to 0.960 (g /
cm^Three), Preferably 0.890 to 0.940 (g / c
m^Three), More preferably 0.900 to 0.930 (g
/ Cm^Three), Particularly preferably 0.905 to 0.925
(G / cm^Three(A-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 3 to 200 (g / 10
Min), preferably 5 to 100 (g / 10 min), more preferably
Preferably 5 to 50 (g / 10 minutes), particularly preferably 10
-50 (g / 10 min) (A-3) 190 ° C, melt at 10.0 kg load
Flow rate (MFR _10.0) And 190 ° C, 2.16 Kg
Melt flow rate under load (MFR_2.16) And ratio
 (MFR_10.0) / (MFR_2.16) = 1-20, preferred
1 to 15, more preferably 1 to 10, particularly preferred
Or 3 to 8 (A-4) molecular weight distribution (Mw / Mn) = 2.0 to 4.0,
Preferably 2.3 to 3.7, more preferably 2.5 to 3.7.
3.5, particularly preferably 2.6 to 3.4

Among the above properties, (1) if the density is smaller than the above range, the minimum rigidity required for the blow-molded product cannot be obtained, and it does not serve as a container.

(2) If the MFR _2.16 is smaller than the above range, the fluidity is poor and the molding of the preform becomes difficult. On the other hand, if it is larger than the above range, the drawdown becomes large and molding becomes difficult.

(3) If (MFR _10.0 ) / (MFR _2.16 ) is larger than the above range, the stretchability is reduced, the thickness of the molded product becomes more uneven, and the surface smoothness is reduced.

(4) If the molecular weight distribution (Mw / Mn) is larger than the above range, the stretchability decreases, the variation in the thickness of the molded product increases, and the surface smoothness decreases.

In the present invention, the ethylene-α-olefin copolymer as the component (A) preferably further has the following properties. (A-5) Swell ratio (SR) SR ≦ 1.35, more preferably SR ≦ 1.30, particularly preferably SR ≦
1.20 (A-6) Temperature rise Standard deviation of the elution amount with respect to the elution temperature obtained by elution fractionation (TREF) σ ≦ 17, more preferably σ ≦ 16, particularly preferably σ ≦ 14 (A-7) Temperature rise The differential elution curve obtained by elution fractionation (TREF) has a plurality of peaks. Among the above characteristics, (5) When the swell ratio (SR) is larger than the above range, the stretchability is reduced, and The variation in thickness increases,
Also, the surface smoothness decreases. If the swell ratio (SR) is smaller than the above range, the stability of the parison decreases. (6) If the standard deviation σ of the elution amount with respect to the elution temperature is larger than the above range, the amount of the adhesive component in the polymer increases. In some cases, the molded products tend to stick to each other, causing a problem. (7) When the differential elution curve obtained by TREF has the above peak, compared with the case where the differential elution curve has one peak,
Transparency is further improved.

The number of peaks of the differential elution curve obtained by the above TREF is a calculation obtained by differentiating the integrated elution curve twice at a temperature range of 0 to 135 ° C., preferably in increments of 1 ° C., preferably in increments of 2 ° C. The value is plotted on the vertical axis and the elution temperature is plotted on the horizontal axis, and the calculated value obtained by differentiating twice is the number of convex inflection points. Then, the sum of all the differential values obtained by one differentiation is standardized as 100, and the differential value (T1, except 0 ° C. and 134 ° C.)
(T1−2) between the differential value and the differential value (T2) that is 2 ° C. lower than the differential value.
T2) is a number of differential values in which the difference (T3-T1) from the differential value (T3) higher than 0 and 2 ° C. higher than the differential value (T1) is −0.15 or less, particularly preferably the integral value. The sum of all the differential values obtained by differentiating the elution curve once at a temperature of 2 ° C. is defined as 100, and the differential value (T1, excluding 0 ° C. and 134 ° C.) and 2% from the differential value ℃ lower differential value (T
2) is greater than or equal to 0.01, and the difference (T3−) from the differential value (T3) that is higher than the differential value (T1) by 2 ° C.
T1) is the number of differential values where -0.20 or less.

The ethylene-α-olefin copolymer as the component (A) can be produced by copolymerizing ethylene with an α-olefin having 3 to 10 carbon atoms in the presence of a single-site catalyst.

The α-olefin having 3 to 10 carbon atoms includes propylene, butene-1, pentene-1, hexene-
1,4-methylpentene-1, octene-1 and the like.

The repeating unit derived from α-olefin in the copolymer of ethylene and α-olefin is as follows:
Usually, it is preferably in the range of 10 mol% or less, more preferably in the range of 0.1 to 5 mol%, and particularly preferably in the range of 0.1 to 5 mol%.
-4% by mole. α-olefin is
The ethylene-α-olefin copolymer may be used alone or in combination of two or more.

As the single-site catalyst, a combination of a metallocene compound of a transition metal of Group IV or V of the periodic table with an organoaluminum compound and / or an ionic compound is used.

The transition metals of Group IV or V of the Periodic Table include:
Titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V) and the like are preferable.

The metallocene compound is a compound which is crosslinked by at least one cyclopentadienyl group, substituted cyclopentadienyl group, hydrocarbyl silicon, or the like. Further, the cyclopentadienyl group is crosslinked by oxygen, nitrogen and phosphorus atoms. Any known metallocene compound having a compound as a ligand can be used.

Specific examples of these metallocene compounds include dimethylsilyl (2,4-dimethylcyclopentadienyl) (3 ', 5'-dimethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (2,4-dimethyl Silicon-bridged metallocene compounds such as cyclopentadienyl) (3 ', 5'-dimethylcyclopentadienyl) hafnium dichloride, ethylenebisindenylzirconium dichloride, ethylenebisindenylhafnium dichloride, ethylenebis (methylindenyl)
Examples include indenyl-based cross-linked metallocene compounds such as zirconium dichloride and ethylenebis (methylindenyl) hafnium dichloride.

The organoaluminum compound used in combination with the metallocene compound in the present invention is represented by the following general formula:
A linear or cyclic polymer represented by (-Al (R) O-) n (R is a hydrocarbon group having 1 to 10 carbon atoms and partially substituted with a halogen atom and / or an RO group) N is the degree of polymerization and is 5 or more, preferably 10 or more), and specific examples are methylalumoxane, ethylalumoxane, and isobutylethylalumoxane, wherein R is a methyl, ethyl, or isobutyl group, respectively. And the like.

Further, examples of other organoaluminum compounds include trialkylaluminum, dialkylhalogenoaluminum, sesquialkylhalogenoaluminum, alkenylaluminum, dialkylhydroaluminum, and sesquialkylhydroaluminum.

The ionic compound is represented by the general formula: C ^+.
Represented by A ⁻ , C ⁺ is an oxidizing cation of an organic compound, an organometallic compound, or an inorganic compound, or a Bronsted acid comprising a Lewis base and a proton, and reacts with an anion of a metallocene ligand to form a metallocene; Cations can be generated. Specific examples thereof include JP-A-4-253711, JP-A-4-305585,
JP-A-5-507756, JP-A-5-502906
Japanese Patent Application Publication No. JP-A-2005-26095 can be used.

Particularly, an ionic compound of a tetrakis (pentafluorophenyl) borate anion and a triphenylcarbonium cation or a dialkylanilinium cation is preferred. These ionic compounds can be used in combination with the aforementioned organic aluminum compounds.

As the (co) polymerization method of ethylene using a single-site catalyst, various well-known methods can be employed, and fluidized bed gas phase polymerization or stirring gas phase polymerization in an inert gas, Examples thereof include slurry polymerization in a solvent and bulk polymerization using a monomer as a solvent.

The high-density polyethylene (B) of the present invention comprises:
It has the physical properties in the specific range described above (however,
((A) Excluding ethylene-α-olefin copolymer)). (B-1) Density (d) = 0.935 exceeding 0.970
Below (g / cm^Three), Preferably 0.940 to 0.97
0 (g / cm^Three), Particularly preferably 0.950 to 0.9.
70 (g / cm^Three(B-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 0.01-20 (g / 1
0 min), preferably 0.1 to 10 (g / 10 min),
Preferably 0.1 to 5 (g / 10 min), particularly preferably
Is 0.1 to 3 (g / 10 minutes)

When the density (d) is out of the above range, the effect of improving rigidity is not sufficient. (B-2) When MFR _2.16 is out of the above range, (A)
The compatibility with the components is poor, and good surface smoothness cannot be obtained.

Examples of the high-density polyethylene include a homopolymer of polyethylene or a copolymer of ethylene and a small amount of α-olefin. For example, a Philips method obtained by polymerizing using a catalyst such as chromium oxide supported on ethylene and alumina or silica-alumina, a standard method obtained by polymerizing using a catalyst such as molybdenum oxide supported on alumina, etc. Examples include polyethylene, polyethylene obtained by polymerization using a Ziegler-based catalyst composed of a transition metal compound and an organometallic compound, and the like.

(C) High-pressure low-density polyethylene of the present invention
Has physical properties in the following specific ranges (however,
However, the (A) ethylene-α-olefin copolymer is excluded.
H). (C-1) Density (d) = 0.915 to 0.935 (g /
cm^Three), Preferably 0.920 to 0.935 (g / c
m^Three), Particularly preferably 0.925 to 0.935 (g / g).
cm^Three(C-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 0.01 to 30 (g / 1
0 minutes), preferably 0.05 to 10 (g / 10 minutes).
0.05 to 5 (g / 10 minutes)

When the density (d) is more than the above range, the effect of improving the transparency is not sufficient. (C-2) If the MFR _2.16 is larger than the above range, the parison stability at the time of molding decreases. When MFR _2.16 is smaller than the above range, the fluidity during molding is deteriorated, the resin pressure during molding is increased, the motor load current is increased, and melt fracture is likely to occur.

In the present invention, the high-pressure low-density polyethylene as the component (C) preferably has the following properties. (C-3) 190 ℃, melt flow rate in 10.0Kg Load (MFR _{1 0.0)} and 190 ° C., 2.16 Kg
Ratio to the melt flow rate (MFR _2.16 ) under load 1 ≦ (MFR _10.0 ) / (MFR _2.16 ) ≦ 100, more preferably 1 ≦ (MFR _10.0 ) / (MFR _2.16 ) ≦
20, particularly preferably 5 ≦ (MFR _10.0 ) / (MFR
_2.16 ) ≦ 20

The high-pressure low-density polyethylene as the component (C) can be produced by high-pressure radical polymerization.

As the high-pressure low-density polyethylene, a copolymer with another monomer such as an ethylene-vinyl acetate copolymer can be used in addition to a homopolymer of ethylene.
When an ethylene-vinyl acetate copolymer is used, the amount of the repeating unit derived from vinyl acetate in the copolymer is usually preferably 20% by weight or less.

The polyethylene composition of the present invention has a temperature of 190 ° C.
Is 2.5 g or more, preferably 2.6 g or more, more preferably 2.7 g or more, and particularly preferably 3.0 g or more.

If the melt tension of the polyethylene composition at 190 ° C. is smaller than the above range, the parison at the time of molding lacks stability.

The polyethylene composition of the present invention has a temperature of 190 ° C.
In which the critical shear rate is 400 / sec or more, more preferably 500 / sec or more, especially 650 / sec or more can be preferably used.

When the critical shear rate at 190 ° C. of the polyethylene composition is smaller than the above range, melt fracture may occur during molding and the appearance of the container may be deteriorated.

The proportion of each component in the polyethylene composition of the present invention is as follows: (A) the ethylene-α-olefin copolymer is 18 to 80% by weight, preferably 20 to 70% by weight.
%, More preferably 20 to 60% by weight, particularly preferably 30 to 50% by weight, and (B) 18 to 80% by weight, preferably 20 to 70% by weight, more preferably 30 to 70% by weight of high density polyethylene. % By weight, particularly preferably 40 to 60% by weight, and (C) 2 to 40% by weight, preferably 5 to 30% by weight of a high-pressure low-density polyethylene,
More preferably, 5 to 20% by weight, particularly preferably 5 to 20% by weight.
15% by weight.

The polyethylene composition of the present invention is obtained by mixing and kneading each component using various kneaders such as a Banbury mixer, a roll mixer, a kneader, a high-speed rotary mixer and an extruder, preferably a single screw or twin screw extruder. Can be obtained. Also, kneading can be performed during film inflation or T-die molding. Alternatively, they can be mixed by a solution blend using an appropriate good solvent.

The injection molding resin of the present invention may be selected from lubricants such as higher fatty acids, higher aliphatic amides, metal soaps and glycerin esters, natural silica, synthetic silica,
Talc, diatomaceous earth and other anti-blocking agents, phenol-based, phosphorus-based, antioxidants such as BHT, benzophenone,
UV absorbers such as benzotriazole and HALS, aluminum hydroxide, magnesium hydroxide, flame retardants such as phosphorus and halogen, inorganic and organic fillers such as silica, calcium carbonate, mica and carbon black, azo and phthalocyanine , Quinacridone, iron oxide, ultramarine blue and other pigments,
An antistatic agent, a surfactant and the like can be added.

The polyethylene composition of the present invention can be suitably used for a single-layer or multi-layer blow molding method. Various methods can be applied as blow molding (blow molding) or hollow molding. For example, extrusion blow molding in combination with extrusion molding, twin-screw extrusion blow molding, injection blow molding in combination with an injection molding machine, and the like can be mentioned. Particularly, it is preferably used in the direct blow molding method from the viewpoint of moldability and drawdown properties.

When the polyethylene of the present invention is used for multilayer blow molding, it can be used for any layer. Especially,
It is preferable to use the outermost layer in view of heat resistance (peelability at high temperatures), transparency and chemical resistance.

The polyethylene composition of the present invention can be molded by blow molding into bottles of foods, cosmetics, pharmaceuticals, detergents, body cleansing agents, soft drinks, milk, etc., infusion bags, and back-in-boxes for filling liquids. Blow molded products such as automobile parts such as bags, instrument panels and tanks such as BIB), toys and industrial parts.

The polyethylene composition of the present invention and a blow-molded product using the same can be used for at least 100 hours,
It is preferable to have a bottle stress cracking of not less than 00 hours, especially not less than 250 hours, because of its excellent chemical resistance.
It is preferable to have haze as the transparency of 3% or less because the transparency is excellent.

[0051]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The characteristic values were measured as follows.

Method for Measuring Polyethylene Properties [1] Density: 190 according to JIS K7112
The strand obtained at the time of MFR measurement under a load of 2.16 kg at 100 ° C. was heat-treated at 100 ° C. for 1 hour, and the sample which was gradually cooled to room temperature over 1 hour was measured using a density gradient tube. [2] Melt flow rate (MFR _2.16 ): JIS
In accordance with K7210, 19
It was determined by measuring the weight of the resin extruded in a strand shape for 10 minutes at a load of 2.16 kg at 0 ° C. [3] Melt flow rate ratio (MFR _10.0 ) / (MFR
_2.16 ): A value obtained by dividing MFR _10.0 obtained with a load of _10.0 kg by MFR _2.16 in the same manner as in the above method (2).

[4] Molecular weight distribution: The molecular weight distribution (Mw / Mn) of the polyethylene composition was measured by gel permeation chromatography (GPC). The measurement method is shown below. (1) Measuring device: WATERS 150CV was used. (2) Measurement sample: polyethylene composition at a temperature of 14
It was dissolved in a solvent (o-dichlorobenzene) at 5 ° C at a concentration of 1 mg / ml. (3) Measurement of molecular weight distribution: Measurement sample of (2) above.
4 ml was injected into two GPC columns AT-806MS, and the solvent was o-dichlorobenzene, the temperature was 145 ° C., and 1.
Performed at a flow rate of 0 ml / min. 35 measured by GPC
Minutes. The polymer concentration in the solution separated by the GPC column was measured with a differential refractometer (RI). The molecular weight was converted using a polystyrene standard. (4) Data processing: Data processing is performed in VAX-STATI
ON3100 was used. G obtained by the above measurement (3)
When a baseline is drawn on the PC chromatogram, the area is integrated using data processing software attached to the apparatus, and the number average molecular weight (Mn), weight average molecular weight (Mw), Mw / Mn
Is automatically calculated. The GPC chromatogram was performed on the screen of the apparatus at 13 mm per 20 with the horizontal axis representing 125 mm per 20 minutes of measurement time and the vertical axis representing the total integrated elution amount as 100.

[5] Swell ratio: Using a Toyo Seiki Capillograph 1C, an orifice with a temperature of 190 ° C., a diameter of 2.09 mmφ, and a length of 8 mm (with a taper), 10 mm /
The diameter (Ds) of the molten strand 7 mm below the nozzle when the resin was extruded at a speed of min was measured with a laser and divided by the orifice diameter (Do) (Ds / Do). [6] Melt tension (MT): Using Toyo Seiki Capillograph 1C, temperature 190 ° C., diameter 2.09 mmφ,
The measurement was performed with an orifice having a length of 8 mm (with a taper) at an extrusion speed of 10 mm / min and a winding speed of 20 m / min. [7] Critical shear rate (FP): Using Toyo Seiki Capillograph 1C, the shear rate is changed by an orifice having a temperature of 190 ° C., a diameter of 2.09 mmφ, and a length of 8 mm (with a taper), thereby causing fracture in the strand. The speed was measured. This measurement was performed visually.

The measurement of the differential elution curve of the polyethylene composition of the present invention by temperature rise elution fractionation (TREF) was performed by the following method. The measurement was carried out using a cloth separation device (CFC T150A manufactured by Mitsubishi Chemical Corporation) as a measuring device according to the measuring method in the attached operation manual. This cross separation apparatus separates a sample by using a difference in dissolution temperature (difference in crystallinity of a polymer), and a temperature-rise elution separation (TREF).
And a gel permeation chromatograph (GPC) that further separates the fractionated fraction by molecular weight. (1) Measurement sample: The polymer was dissolved in a solvent (o-dichlorobenzene) at a temperature of 135 ° C and a concentration of 3 mg / ml, and injected into a sample loop of a measurement device. The following measurements were performed automatically according to the set conditions. (2) The measurement sample held in the sample loop is
Separation is performed using the temperature difference of dissolution, and a TREF column (inside diameter of 4 mm, length 1 packed with glass beads as an inert carrier)
0.5 ml into a 50 mm stainless steel column). (3) The measurement sample for injection was 1 in the TREF column.
It is cooled at a rate of 1 ° C./min from 35 ° C. to 0 ° C. and coated on an inert carrier (glass beads). (4) After the TREF column is maintained at a temperature of 0 ° C. for 30 minutes,
2 ml of the component dissolved at a temperature of 0 ° C. was transferred from the TREF column to the GPC column (Shodex) at a flow rate of 1 ml / min.
AT-806M / S × 3). (5) The concentration of the polymer in the solution fractionated by the molecular weight with the GPC column was measured by an infrared spectrophotometer (IR) (wavelength 3.
42 nm). (6) While fractionation based on molecular weight is being performed on the GPC column, the temperature of the TREF column is raised to the next elution temperature (10 ° C.) and maintained at that temperature for about 30 minutes. GPC
Is performed at 40 minute intervals. Thereafter, the elution temperature is increased stepwise in the following temperature order, and the samples separated at each elution temperature are subjected to molecular weight separation by GPC,
The measurement is repeated. Elution temperature order: 0 ° C, 10
° C, 20 ° C, 25 ° C, 30 ° C, 35 ° C, 40 ° C, 45 ° C
℃, 49 ℃, 52 ℃, 55 ℃, 58 ℃, 61 ℃, 64
° C, 67 ° C, 70 ° C, 73 ° C, 76 ° C, 79 ° C, 82
85 ° C, 88 ° C, 91 ° C, 95 ° C, 100 ° C, 10 ° C
5 ° C, 120 ° C, 135 ° C (28 fractions). (7) Data processing is automatically performed using data processing software attached to the device. The analysis order is [1] above (5),
A baseline is drawn on the GPC chromatogram at each elution temperature obtained in the measurement of (6), and the area is integrated.
[2] The integrated elution curve is calculated as the horizontal axis / elution temperature and vertical axis / integral value of GPC chromatogram. [3] The integrated elution curve is differentiated by temperature, and a differential elution curve is calculated and plotted as a calculated value of the horizontal axis / elution temperature and the vertical axis / differential.
[4] The calculation result is plotted. The size of the figure is 15 mm per 20 with the horizontal axis representing the elution temperature of 127.6 mm per 140 ° C. and the vertical axis representing the total integrated elution amount as 100.

[8] Standard deviation of the elution amount with respect to the elution temperature obtained by temperature rise elution fractionation (TREF) σ:
Using the data processing software attached to the instrument, the above-mentioned integrated elution curve (total integrated elution amount was set to 100) was used to determine the temperature from 0 to 13
In the range of 5 ° C., a differential value (2 decimal places) in increments of 2 ° C. is calculated. The standard deviation σ was calculated using the differential value.

Method for Evaluating Formability (1) Blow Formability: Japan Steel Blow Molding Machine JB-
Using a mold 105, a 500 ml container was molded under the molding conditions of a resin temperature of 190 ° C. and a mold temperature of 20 ° C. Molded 5
The product moldability (surface state of the parison at the time of processing, drawdown property) of the 00 ml container and the surface smoothness of the bottle product were visually evaluated. Moldability judgment method ○: No moldability problem, ×: Moldability problem Surface smoothness judgment method ○: Good, ×: Poor (2) Bottle stress cracking (BSCR):
A bottle stress cracking tester manufactured by Yasuda Seiki Seisakusho Co., Ltd. was used. As test bottles, five 500 ml containers molded in the above (1) were used. An aqueous solution containing 10% by weight of an alkylphenol-type surfactant (Nonion NS-210 manufactured by NOF Corporation) was added to a test bottle.
After filling / 4 volume, temperature is 60 ℃, internal pressure is 0.35kg
Under the condition of / cm ² , the time when cracks occurred in 50% of the number of test bottles was measured. (4) Transparency: The haze of the bottle body of the 500 ml container molded in (1) was measured according to JIS K7105. The thickness of the bottle body is about 0.5 mm
Met. (5) Peelability: The polyethylene composition for blow molding was press-molded at a temperature of 180 ° C. for 6 minutes under a pressure of 100 kg / cm ² , and a 0.5 mm thick, 10 cm square film was formed.
I made two copies. Two sheets of this film are stacked, and the temperature is 115
The substrate was heated and adhered at a load of 2 g / cm ² for 30 minutes. The adhesion of the two films was evaluated. ：: peels off, ×: adheres and does not peel

Examples 1 to 3 and Comparative Examples 1 to 5 Polymer (A) used in each of Examples and Comparative Examples, (B)
The properties of the component and the component (C) are shown in Tables 1, 2 and 3. Table 4 shows the compositions used for blow molding and the evaluation of their resin properties. Table 5 shows the blow molding obtained from the composition shown in Table 4 using a JB-105 blow molding machine made by Nippon Steel Corporation and the characteristics of the resulting molded container.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

[Table 4]

[0063]

[Table 5]

[0064]

EFFECTS OF THE INVENTION The polyethylene composition for blow molding of the present invention and the blow molded product formed by using the same are suitable for the production of blow molded products such as bottles. It has excellent smoothness, chemical resistance, and heat resistance (peelability at high temperatures).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tohru Chiyo 8-1, Goi south coast, Ichihara City, Chiba Prefecture Ube Industries, Ltd. Chiba Petrochemical Plant

Claims (3)

[Claims] (A) Ethylene-α-olefin copolymer
18-80% by weight of body, (B) high-density polyethylene 18-
80% by weight and (C) high pressure method low density polyethylene 2-4
0 wt% melt tension at 190 ° C
Is a polyethylene composition of 2.5 g or more,
(A) an ethylene-α-olefin copolymer, (B)
High density polyethylene and (C) high pressure method low density polyethylene
Characterized in that the styrene has the following properties, respectively.
Polyethylene composition for blow molding. (A) Ethylene-α-olefin copolymer: (A-1) Density (d) = 0.880 to 0.960 (g /
cm^Three(A-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 3 to 200 (g / 10
(A-3) Melt at 190 ° C. and 10.0 kg load
Flow rate (MFR _10.0) And 190 ° C, 2.16 Kg
Melt flow rate under load (MFR_2.16) And ratio
 (MFR_10.0) / (MFR_2.16) = 1 to 20 (A-4) Molecular weight distribution (Mw / Mn) = 2.0 to 4.0 (B) High-density polyethylene (provided that the (A) ethylene
(Excluding -α-olefin copolymer): (B-1) Density (d) = 0.935 exceeding 0.935
Below (g / cm^Three(B-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 0.01-20 (g / 1
0 minutes) (C) High-pressure low-density polyethylene (provided that (A)
(Excluding the Tylene-α-olefin copolymer): (C-1) Density (d) = 0.915 to 0.935 (g /
cm^Three(C-2) Melt at 190 ° C. and 2.16 Kg load
Flow rate (MFR _2.16) = 0.01 to 30 (g / 1
0 minutes) 2. A critical shear rate at 190 ° C. of 40
2. The polyethylene composition for blow molding according to claim 1, wherein the polyethylene composition is 0 / sec or more. 3. A blow molded product obtained by molding using the polyethylene composition for blow molding according to claim 1.