JPH107848A - Resin composition for blow molding and medical container composed thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition composed of a specific ethylene/α- olefin copolymer and a low-density polyethylene, having excellent blow- moldability, transparency and sterilization heat-resistance and suitable as a liquid container for cosmetic, etc., a transfusion bag, etc. SOLUTION: This resin composition is composed of (A) ethylene/α-olefin copolymers having an Mw /Mn ratio of <=3 (Mw and Mn are weight-average molecular weight and number-average molecular weight, respectively), satisfying the relationship of the formula [Tm is the maximum peak temperature ( deg.C) of the endothermic curve obtained by a differential scanning calorimetry: SCB is the number of short-chain branches per 1,000C atoms determined from an infrared absorption spectrum] and composed of (A1 ) a copolymer having a melt-flow rate(MFR) of 0.1-8(g/10min) and (A2 ) a copolymer having an MFR of 8-100 and (B) a low-density polyethylene having a density of 0.91-0.935g/cm<3> and produced by high-pressure radical polymerization method. The weight ratios of A2 /A1 and A/B are 80/20 to 20/80 and 95/5 to 40/60, respectively, and the ratio of MFR of A2 to that of A1 is 5-100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a resin composition for blow molding. More specifically, liquid containers such as cosmetics that require processability and transparency, containers for high-purity chemicals used in semiconductor manufacturing processes that require cleanliness, and medical containers that require sterile heat resistance. And the like.

[0002]

2. Description of the Related Art Low-density polyethylene (hereinafter referred to as "HP-LDPE") obtained by a high-pressure radical polymerization method has a long chain branch in a molecular chain, and therefore has a high melt tension and excellent fluidity under high shear. It is widely used as a resin for blow molding since a blow molded product having a uniform thickness and a good surface condition can be obtained.

However, since HP-LDPE has a relatively low melting point, there is a problem that heat resistance is insufficient when used as a medical container requiring heat sterilization such as an infusion bag. Further, since the mechanical strength of HP-LDPE is low, the strength of the pinch-off portion is low in the blow molded article,
There is also a problem in terms of reliability that can withstand severe conditions such as heat treatment. Therefore, despite the fact that HP-LDPE has excellent properties in terms of processability, its use range is limited, and it cannot be used as a medical container.

On the other hand, as a material having heat resistance and mechanical strength that can withstand heat sterilization, an ethylene / α-olefin copolymer obtained with a conventionally known Ziegler-type catalyst is known. However, since these do not have long-chain branches in the molecular chain, HP-LDPE with the same melt flow rate is used.
Therefore, there is a problem that molding is difficult because the melt tension is low and the drawdown during blow molding is large.

[0005] From the above, a blend of an ethylene / α-olefin copolymer and HP-LDPE is used in an actual blow molding material for the purpose of making the most of each characteristic.

[0006] Recently, with the amendment of the Japanese Pharmacopoeia, regulations on transparency have been introduced for medical containers such as infusion bags to facilitate identification of foreign substances mixed in the filling. The problem here is that the ethylene / α-olefin copolymer obtained with the Ziegler type catalyst and the HP-LD
The point is that transparency satisfying the above-mentioned requirements cannot be obtained by blending PE. In general, the ethylene / α-olefin copolymer decreases the density and increases the transparency by increasing the α-olefin content, but the ethylene / α-olefin copolymer obtained with the Ziegler-type catalyst has a composition Due to the broad distribution, there are components with high crystallinity even at low density. This is a favorable property for sterilization heat resistance, but has an adverse effect on transparency,
-There was naturally a limit in trying to obtain a highly transparent container by blending with LDPE.

On the other hand, when an ethylene / α-olefin copolymer having a narrow composition distribution obtained by using a metallocene catalyst is used, high transparency is exhibited even in a composition blended with HP-LDPE by lowering the density. Although it is possible to do so, the sterilization heat resistance becomes insufficient, and conversely, as the density increases, the transparency decreases.

Accordingly, in the composition comprising an ethylene / α-olefin copolymer and an HP-LDPE obtained by using a metallocene catalyst, the cooling rate at the time of molding such as water-cooled or air-cooled inflation molding is relatively high, and As long as the container has a small thickness, it can be used as a medical container having both transparency and sterilization heat resistance. However, when molding a container having a slow cooling rate at the time of molding and a thick molded body (normally 200 μm or more), such as blow molding, it is difficult to satisfy both of the above-mentioned required characteristics. Had a problem.

Furthermore, the ethylene / α-olefin copolymer obtained by the metallocene catalyst has a low molecular weight distribution and therefore has poor fluidity, and still has the problem that surface roughness such as sharkskin and melt fracture occurs during blow molding. Exists.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a composition comprising an ethylene / α-olefin copolymer and HP-LDPE, which is excellent in moldability, transparency and sterilization heat resistance, and is used for liquid containers such as cosmetics. An object of the present invention is to provide an unprecedented blow molding resin composition suitable for medical use such as an infusion bag.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that ethylene / α-olefins having a narrow molecular weight distribution and composition distribution and having a specific melt flow rate. In the mixture of copolymers,
The composition blended with HP-LDPE having a specific melt flow rate has favorable flow characteristics and transparency for blow molding, and the crystallinity of the ethylene / α-olefin copolymer is in a specific range. In this case, it was found that in addition to the blow moldability and the transparency, it was excellent in sterilization heat resistance.

That is, the present invention provides the following (a):
Among the ethylene / α-olefin copolymers satisfying the requirements of (b), the melt flow rate (hereinafter, referred to as MFR) measured at 190 ° C. under a load of 2.16 kg is 0.1 to 0.1.
8 g / 10 min of copolymer [AI] and MFR of 8 to 1
It comprises a copolymer [AII] having a flow rate of 00 g / 10 minutes and a low-density polyethylene (hereinafter referred to as [B]) obtained by a high-pressure radical polymerization method satisfying the following requirements (c) and (d). ] / [AI] weight ratio of 80/20 to 20
/ 80, and M of component [AII] and component [AI]
The FR ratio (MFRII / MFRI) is in the range of 5 to 100, and the weight ratio of ([AI] + [AII]) / [B] is 9
The present invention relates to a resin composition for blow molding, wherein the composition is 5/5 to 40/60.

[0013] (a) In the weight average molecular weight (M _w) and number average molecular weight ratio _{(M n) (M w /} M n) is 3 or less (b) a differential scanning calorimeter, and melted for 5 minutes at 200 ° C. Then, the temperature was lowered to 30 ° C. at 10 ° C./min,
The temperature (T _m (° C.)) at the maximum peak position of the endothermic curve obtained when the temperature was raised at a rate of ° C./min and the number of short-chain branches (SCB) per 1000 carbon atoms determined from the measurement of the infrared absorption spectrum. Satisfies the relationship represented by equation (1).

T _m <−1.5 × SCB + 138 (1) (c) Density 0.910 to 0.935 g / cm ³ (d) MF measured at 190 ° C. under a load of 2.16 kg
R is 0.1 to 3 g / 10 minutes The ethylene / α-olefin copolymer ([AI] and [AII]) has a weight average molecular weight (M _w ) and a number average molecular weight (M _n ) ratio (M _w ). / M _n ) is 3 or less. M _w / M
_{If n} exceeds 3, the wax component increases, the cleanliness when used as a medical container decreases, and blocking occurs due to the sterilization treatment, which causes a decrease in transparency and stickiness, which is not preferable.

The ethylene / α-olefin copolymer has a short-chain branching number (SC) per 1000 carbon atoms determined from T _m (° C.) and infrared absorption spectrum measurement.
B) satisfy the relationship of the expression (1). Ethylene / α-olefin copolymers that do not satisfy this formula are not preferred because of their wide composition distribution and the presence of highly crystalline components that adversely affect transparency.

T _m <−1.5 × SCB + 138 (1) The ethylene / α-olefin copolymer of [AI] is 19
The MFR measured at 0 ° C. under a load of 2.16 kg is 0.1
８8 g / 10 min. MFR is 0.1g / 10
If it is less than minutes, uniform kneading with [AII] becomes difficult,
If the MFR exceeds 8 g / 10 minutes, the drawdown becomes large and blow molding becomes difficult.

The ethylene / α-olefin copolymer [AII] has an MFR in the range of 8 to 100 g / 10 minutes. When the MFR is less than 8 g / 10 minutes, the effect of improving the fluidity by blending with [AI] is not observed, and the MFR is less than 10 g.
If it exceeds 0 g / 10 min, the cleanliness when used as a medical container is reduced, and the transparency and stickiness are reduced due to blocking.

The ethylene / α-olefin copolymer compositions [AI] and [AII] have a weight ratio of [AII] / [AI] in the range of 80/20 to 20/80. A composition out of this range does not show a fluidity improving effect.

The M of the component [AII] and the component [AI]
The FR ratio (MFRII / MFRI) is in the range of 5-100. When MFRII / MFRI is less than 5, no fluidity improving effect is obtained, and when MFRII / MFRI exceeds 100, it becomes difficult to uniformly knead [AI] and [AII].

[AI] and [AII] are represented by [A
An ethylene / α-olefin copolymer composition [C] comprising [I] and [AII] can be used. In this case, the ethylene / α-olefin copolymer composition [C] has M
Preferably, the FR is in the range of 0.3 to 10 g / 10 minutes. If the MFR is less than 3 g / 10 minutes, the melt viscosity becomes high and processing becomes difficult. On the other hand, if it exceeds 10 g / 10 minutes, the drawdown becomes large and blow molding becomes difficult.

Further, the ethylene / α-olefin copolymer composition [C] has a residual crystallinity at 110 ° C. of 5
It is preferably in the range of not less than 40% by weight and not less than 40% by weight. When the residual crystallinity is less than 5% by weight, the heat resistance is insufficient, and the molded product is deformed or deteriorated in transparency due to sterilization treatment. On the other hand, if the content is 40% by weight or more, a component having high crystallinity that adversely affects the transparency is present, so that the intended effect cannot be obtained.

The ethylene / α-olefin copolymer ([AI] and [AII]) can be obtained, for example, using a metallocene catalyst. Hereinafter, the catalyst system and the polymerization method will be exemplified.
The method for producing the α-olefin copolymer is not limited to this.

Specifically, examples of the metallocene-based catalyst include a catalyst system comprising a) a metallocene compound, b) an ionic compound, and c) an organoaluminum compound.

A) Metallocene compound represented by the following general formula (2)
Or (3)

[0025]

Embedded image

[0026]

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Wherein Cp ¹ and Cp ² are each independently a cyclopentadienyl group, an indenyl group, a fluorenyl group or a substituted product thereof, R ¹ is a lower alkylene group,
A substituted alkylene group, a dialkylsilanediyl group, a dialkylgermandiyl group, an alkylphosphinediyl group or an alkylimino group, R ¹ acts to crosslink Cp ¹ and Cp ² , and R ² and R ³ each represent Independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group or an aryloxy group, and M ¹ is a titanium atom, a zirconium atom or a hafnium atom]. Typical compounds include bis (cyclopentadienyl) titanium dichloride, bis (methylcyclopentadienyl) titanium dichloride, bis (butylcyclopentadienyl) titanium dichloride, ethylenebis (indenyl) titanium dichloride, dimethylsilanediylbis (2,4,5-tri Methylcyclopentadienyl) titanium dichloride, dimethylsilanediylbis (2,4-dimethylcyclopentadienyl) titanium dichloride, dimethylsilanediylbis (3-methylcyclopentadienyl) titanium dichloride, dimethylsilanediylbis (4- t-butyl, 2-methylcyclopentadienyl) titanium dichloride, diethylsilanediylbis (2,4,5-trimethylcyclopentadienyl) titanium dichloride, diethylsilanediylbis (2,4-dimethylcyclopentadienyl) Titanium dichloride, diethylsilanediylbus (3-methylcyclopentadienyl) titanium dichloride, diethylsilanediylbis (4-t-butyl-2-methylcyclopentadienyl) titanium Dichloride, isopropylidene (cyclopentadienyl)
(Fluorenyl) titanium dichloride, diphenylmethylene (cyclopentadienyl) (fluorenyl) titanium dichloride, methylphenylmethylene (cyclopentadienyl) (fluorenyl) titanium dichloride, isopropylidene (cyclopentadienyl)
(2,7-di-t-butylfluorenyl) titanium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-di-t-butylfluorenyl) titanium dichloride, methylphenylmethylene (cyclopentadienyl) ) (2,7-di-t-butylfluorenyl) titanium dichloride, isopropylidene (cyclopentadienyl) titanium dichloride, diphenylmethylenebis (cyclopentadienyl) titanium dichloride, methylphenylmethylenebis (cyclopentadienyl) ) Titanium dichloride, isopropylidene (cyclopentadienyl) (tetramethylcyclopentadienyl) titanium dichloride, diphenylmethylene (cyclopentadienyl) (tetramethylcyclopentadienyl) tita Umujikuroraido, isopropylidene (indenyl) titanium dichloride, titanium compound or the like diphenylmethylene-bis (indenyl) titanium dichloride, although compounds obtained by substituting the titanium zirconium or hafnium and the like, but is not limited thereto.

[0028] b) an ionic _{^{compound, [HL 1 1] [M}} 2 Z 4] (4) [ wherein, H is a proton, L ¹ is a Lewis base each independently, 1 0 < 1 ≦ 2, M ² is a boron atom, an aluminum atom or a gallium atom, and Z is each independently an alkyl or alkoxy group having 1 to 20 carbon atoms, an aryloxy group or an aryl group having 6 to 20 carbon atoms. , An alkylaryl group or an arylalkyl group, a halogen-substituted aryloxy group having 1 to 20 carbon atoms or a halogen atom], [K] [M ² Z ₄ ] (5) wherein K is carbonyl A cation or a tropylium cation, M ² is a boron atom, an aluminum atom or a gallium atom, and Zs each independently have 1 to 1 carbon atoms.
20 alkyl or alkoxy groups, 6 to 2 carbon atoms
0 aryloxy group, aryl group, alkylaryl group or arylalkyl group, C1-C20 halogen-substituted hydrocarbon group or halogen-substituted alkoxy group, C6-C20 halogen-substituted aryloxy group or halogen atom]. A Lewis acid represented, or [M ³ L ² p] [M ² Z ₄ ] (6) wherein M ³ is a group VIII, IA, IB,
A cation of a metal selected from Group IIA and Group IIB, M ² is a boron atom, an aluminum atom or a gallium atom; Z is each independently an alkyl or alkoxy group having 1 to 20 carbon atoms; An aryloxy group, an aryl group, an alkylaryl group or an arylalkyl group having 1 to 20 carbon atoms, a halogen-substituted hydrocarbon group or a halogen-substituted alkoxy group having 1 to 20 carbon atoms, a halogen-substituted aryloxy group having 6 to 20 carbon atoms or a halogen atom. And L ² is a Lewis acid group or a cyclopentadienyl group, and p is 0 ≦ p ≦ 2]. Specific examples of these compounds include tri ( n-butyl) ammonium tetrakis (p-tolyl) borate, tri (n-butyl) ammonium tetrakis (m- (Tolyl) borate, tri (n-butyl) ammonium tetrakis (2,4-dimethylphenyl) borate, tri (n-butyl) ammonium tetrakis (3,5-dimethylphenyl) borate, tri (n-butyl) ammonium tetrakis (pentane) Fluorophenyl) borate, N, N-dimethylanilinium tetrakis (p-tolyl) borate, N, N-dimethylanilinium tetrakis (m-tolyl) borate, N, N
N-dimethylanilinium tetrakis (2,4-dimethylphenyl) borate, N, N-dimethylanilinium tetrakis (3,5-dimethylphenyl) borate,
N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, triphenylcarbenium tetrakis (p-tolyl) borate, triphenylcarbenium tetrakis (m-tolyl) borate, triphenylcarbenium tetrakis (2,4-dimethyl Phenyl) borate, triphenylcarbeniumtetrakis (3,5-dimetrphenyl) borate, triphenylcarbeniumtetrakis (pentafluorophenyl)
Borate, tropylium tetrakis (p-tolyl) borate, tropylium tetrakis (m-tolyl) borate, tropinium tetrakis (2,4-dimethylphenyl) borate, tropylium tetrakis (3,5-dimethylphenyl) borate, tropylium Tetrakis (pentafluorophenyl) borate, lithium tetrakis (pentafluorophenyl) borate, lithium tetrakis (phenyl) borate, lithium tetrakis (p-
Tolyl) borate, lithium tetrakis (m-tolyl)
Borate, lithium tetrakis (2,4-dimethylphenyl) borate, lithium tetrakis (3,5-dimethylphenyl) borate, lithium tetrafluoroborate, sodium tetrakis (pentafluorophenyl)
Borate, sodium tetrakis (phenyl) borate, sodium tetrakis (p-tolyl) borate, sodium tetrakis (m-tolyl) borate, lithium tetrakis (2,4-dimethylphenyl) borate, lithium tetrakis (3,5-dimethylphenyl) borate Sodium tetrafluoroborate, potassium tetrakis (pentafluorophenyl) borate, potassium tetrakis (phenyl) borate, potassium tetrakis (p-tolyl) borate, potassium tetrakis (m-tolyl) borate, potassium tetrakis (2,4-dimethylphenyl) Borate, potassium tetrakis (3.5
-Dimethylphenyl) borate, potassium tetrafluoroborate, tri (n-butyl) ammonium tetrakis (p-tolyl) aluminate, tri (n-butyl) ammonium tetrakis (m-tolyl) aluminate, tri (n-butyl) ammonium Tetrakis (2,4-dimethylphenyl) aluminate, tri (n-butyl) ammonium tetrakis (3,5-dimethylphenyl) aluminate, tri (n-butyl) ammonium tetrakis (pentafluorophenyl) aluminate, N, N −
Dimethylanilinium tetrakis (m-tolyl) aluminate, N, N-dimethylanilinium tetrakis (2,4-dimethylphenyl) aluminate, N, N-
Dimethylanilinium tetrakis (3,5-dimethylphenyl) aluminate, N, N-dimethylaniliniumtetrakis (pentafluorophenyl) aluminate,
Triphenylcarbenium tetrakis (p-tolyl) aluminate, triphenylcarbenium tetrakis (m
-Tolyl) aluminate, triphenylcarbeniumtetrakis (2,4-dimethylphenyl) aluminate,
Triphenylcarbenium tetrakis (3,5-dimethylphenyl) aluminate, triphenylcarbenium tetrakis (pentafluorophenyl) aluminate,
Tropylium tetrakis (p-tolyl) aluminate,
Tropylium tetrakis (m-tolyl) aluminate,
Tropylium tetrakis (2,4-dimethylphenyl)
Aluminate, tropylium tetrakis (3,5-dimethylphenyl) aluminate, tropylium tetrakis (pentafluorophenyl) aluminate, lithium tetrakis (pentafluorophenyl) aluminate, lithium tetrakis (phenyl) aluminate, lithium tetrakis (p -Tolyl) aluminate, lithium tetrakis (m-tolyl) aluminate, lithium tetrakis (2,4-dimethylphenyl) aluminate, lithium tetrakis (3,5-dimethylphenyl) aluminate, lithium tetrafluoroaluminate, sodium tetrakis (Pentafluorophenyl) aluminate,
Sodium tetrakis (phenyl) aluminate, sodium tetrakis (p-tolyl) aluminate, sodium tetrakis (m-tolyl) aluminate, sodium tetrakis (2,4-dimethylphenyl) aluminate, sodium tetrakis (3,5- Dimethylphenyl)
Aluminate, sodium tetrafluoroaluminate potassium tetrakis (pentafluorophenyl) aluminate, potassium tetrakis (p-tolyl) aluminate, potassium tetrakis (m-tolyl) aluminate,
Examples include, but are not limited to, potassium tetrakis (2,4-dimethylphenyl) aluminate, potassium tetrakis (3,5-dimethylphenyl) aluminate, and potassium tetrafluoroaluminate.

C) The organoaluminum compound is represented by AlR ⁴ R ^{4 ′} R ^{4 ″} (7) wherein R ⁴ , R ^{4 ′} and R ^{4 ″} are each independently hydrogen, halogen, amino group, alkyl group, An alkoxy group or an aryl group, and at least one is an alkyl group]
In these compounds, trimethylaluminum, triethylaluminum, triisopropylaluminum, diisopropylaluminum chloride, isopropylaluminum dichloride, tributylaluminum, triisobutylaluminum, diisobutylaluminum chloride, isobutylaluminum dichloride, Examples include, but are not limited to, tri-t-butyl aluminum, di-t-butyl aluminum chloride, t-butyl aluminum dichloride, triamyl aluminum, diamyl aluminum chloride, amyl aluminum dichloride, and the like.

A) One or two metallocene compounds
More than one type can be used in combination. When two or more metallocene compounds are used in combination, the ethylene / α-
The olefin copolymers [AI] and [AII] are preferable because they can be produced simultaneously in a single reactor.

The method for preparing the catalyst system is not particularly limited, and examples thereof include a method in which each of the metallocene compound, the organoaluminum compound and the ionic compound is mixed in an inert solvent.

The ionic compound is generally used in an amount of 0.01 to 1000 times, preferably 0.2 to 200 times, the mole of the metallocene compound.

The amount of the organoaluminum used is not particularly limited.
It is used about 1000 times in mole. Further, the polymerization using the above catalyst system can be performed in a liquid phase or a gas phase. If the polymerization is carried out in a liquid phase, any organic solvent that is generally used as a solvent may be used, and specific examples thereof include benzene, toluene, hexane, and methylene chloride. In addition, ethylene and α-olefin itself can be used as the solvent.

The α-olefin used in the present invention is an α-olefin having 3 or more carbon atoms, specifically, propylene, butene-1, pentene-1, hexene-1, octene-1, 4-methyl-pentene-. 1 or the like, and one or more of these are used.

There are no particular restrictions on the polymerization temperature,
Usually, it is preferable to carry out in the range of -100 to 300 ° C. Also, the polymerization pressure is not particularly limited, but is usually carried out at atmospheric pressure to 30 kgf / cm ² ,
It is also possible to carry out in the range of 3500 kgf / cm ² .

The above-mentioned catalyst system is used as a solid catalyst supported on a carrier, and the ethylene / α-olefin copolymer of the present invention can be obtained by copolymerizing ethylene with an α-olefin having 3 or more carbon atoms. it can. Such solid catalysts include metallocene compounds, mixtures of metallocene compounds and ionic compounds, reaction products of metallocene compounds and organoaluminum compounds, ionic compounds or organoaluminum compounds themselves, for example, silica, alumina, magnesium chloride. , A styrene-divinylbenzene copolymer or polyethylene.

Next, the low-density polyethylene (HP-LDP) obtained by the high-pressure radical polymerization method of [B] in the present invention is used.
E) has a density in the range of 0.910 to 0.935 g / cm ³ . If the density is less than 0.910 g / cm ³ ,
It is not preferable because blocking occurs in the molded article and cleanliness when used as a medical container is reduced. When the density is greater than 0.935 g / cm ³ , the ethylene / α-olefin copolymer [AI], [A
II], the desired transparency cannot be obtained.

The HP-LDPE of this [B] is 190
MFR measured under a load of 2.16 kg at 0.1 ° C
The range is 3 g / 10 minutes. When the MFR is less than 0.1 g / 10 minutes, it becomes difficult to uniformly knead the ethylene / α-olefin copolymers [AI] and [AII].
When the FR is greater than 3 g / 10 minutes, [AI], [AI
By blending with I), the desired effect of improving transparency cannot be obtained, and the wax component increases, resulting in a decrease in cleanliness when used as a medical container.

The HP-LDPE of [B] can be obtained by a conventionally known high-pressure radical polymerization method.

The composition of the present invention is obtained by adding HP-LDPE to ethylene / α-olefin copolymers [AI] and [AII].
[B] is calculated as 9 by weight ratio of ([AI] + [AII]) / [B].
It can be manufactured by mixing in the range of 5/5 to 40/60. If the blend amount of HP-LDPE [B] is less than 5% by weight, the drawdown becomes large and blow molding becomes difficult. On the other hand, if the blend amount of HP-LDPE [B] exceeds 60% by weight, the desired physical properties cannot be obtained because the transparency and the mechanical strength are reduced. In this case, the ethylene / α-olefin copolymer [AI], [A
The HP-LDPE [B] to be blended with II] may be one kind or a mixture of two or more kinds.

The resin composition for blow molding according to the present invention is obtained by simultaneously polymerizing ethylene / α-olefin copolymers [AI] and [AII] in a single reactor using two or more metallocene catalysts. Granulated ethylene / α-
Olefin copolymer composition [C] and HP-LDPE
[B] may be used by dry blending, or the ethylene / α-olefin copolymer [AI] and [AII] are polymerized and granulated in separate reactors, and then [AI], [AII]
And HP-LDPE [B] may be used by dry blending. [AI], [AII] and HP
-LDPE [B] may be used after melt-kneading with an extruder, kneader, Banbury or the like.

The blow molding resin composition of the present invention comprises an antioxidant, a weather resistance stabilizer, an antistatic agent, a lubricant,
Additives generally used for blocking agents and polyolefins may be added as long as they do not cause a problem in cleanliness when used as medical containers.

[0043]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Ethylene / α in Examples and Comparative Examples
-An ethylene / hexene-1 copolymer was used as the olefin copolymers [AI] and [AII]. The catalyst systems used to obtain these are diphenylmethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride (hereinafter referred to as [E]) and ethylene (bisindenyl) zirconium dichloride (hereinafter referred to as [I]) as metallocene compounds. N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate as the ionized ionic compound and triisobutylaluminum as the organoaluminum compound. The amounts of the metallocene compound, the ionized ionic compound and the organoaluminum are in a molar ratio (metallocene). Compound:
(Ionized ionic compound: organoaluminum)
2: 250. For the preparation of the catalyst, toluene was used as a solvent.

Ethylene / α-olefin copolymer [A
In the case where I] and [AII] are simultaneously polymerized in a single reactor, a solution in which the metallocene compounds [E] and [I] are separately mixed with an ionized ionic compound and an organoaluminum compound is prepared and the reaction system is prepared. Was injected. The injection amount of each catalyst was adjusted so that the molar ratio of zirconium in the metallocene compound was [E]: [I] = 1: 1.

The ethylene / α-olefin copolymer used here was prepared by using the above catalyst system at a polymerization temperature of 100 to 30.
It is obtained by polymerizing at 0 ° C. and a polymerization pressure of 500 to 2000 kgf / cm ² .

The polymerization operation, reaction and solvent purification were all performed in an inert gas atmosphere. The solvents used in the reaction were all purified, dried and deoxygenated by a known method, and the compounds used in the reaction were those synthesized and identified by a known method.

As the low-density polyethylene [B] in Examples and Comparative Examples, those obtained by a high-pressure radical polymerization method were used.

The compositions used in Examples and Comparative Examples were mixed and granulated with a single screw extruder after mixing the components with an appropriate composition. Laboplastomill manufactured by Toyo Seiki Co., Ltd. was used for the melt granulation.

The physical properties of the above-mentioned compositions and the respective mixed components used in the examples and comparative examples were measured by the following methods.

(1) Molecular weight distribution ( _Mw / _Mn ): 150C ALC / GPC manufactured by Waters [Column: GMHHR-H (S) manufactured by Tosoh Corporation, 7.8 mm ID × 30]
cm × 3, solvent 1,2,4-trichlorobenzene, temperature 140 ° C., flow rate 1.0 ml / min, injection concentration 30 mg /
The 30 ml (injection volume 300 [mu] l)] gel permeation chromatography using a gel permeation chromatography (GPC), M _w
And _Mn were measured, and _Mw / _Mn was calculated. The column elution volume was calibrated by universal calibration using standard polystyrene manufactured by Tosoh Corporation.

(2) MFR: JIS K7210 (197)
6 years) at 190 ° C. under a load of 2.16 kg.

(3) N value: MFR (MFR _H ) measured at 190 ° C. under a load of 21.6 kg and NFR at 190 ° C. and 2.16
Ratio to MFR (MFR _L ) measured under a load of kg (M
FR _H / MFR _L ).

(4) Critical shear rate (γ _c ): Capillograph PMD-C manufactured by Toyo Seiki Co., Ltd. [Dice: L (2
0 mm) × D (1 mm) at a measurement temperature of 190 ° C.], and extruding speed from 5 mm / min to 200 mm / min.
And the shear rate (γc) at which sharkskin was formed on the surface of the extruded strand was measured.

(5) Density: JIS K6760 (1981)
), The sample was immersed in hot water at 100 ° C for 1 hour, and then allowed to cool to room temperature, and measured using a density gradient tube kept at 23 ° C.

(6) Melting point: Differential scanning calorimeter (DSC)
Samples were prepared using Perkin Elmer Co., Ltd., DSC-7.
Melting was performed at 00 ° C. for 5 minutes, then the temperature was lowered at 10 ° C./min to 30 ° C., and the temperature was increased again at a rate of 10 ° C./min.

(7) Residual crystallinity (W): From the above endothermic curve, the total heat of fusion (Q _a11 ) and the heat of fusion (Q a) of 110 ° C. or more
₁₁₀ ) was calculated and calculated according to equation (2).

W (% by weight) = {ρ _c (ρ−ρ _a ) / ρ (ρ _c −ρ _a )} × (Q ₁₁₀ / Q _a11 ) (2) [where, ρ is the sample density, ρ _c Is the density of perfect crystals of polyethylene (1.000 g / cm ³ ), and ρ _a is the perfect amorphous density (0.855 g / cm ³ ). (8) Number of short-chain branches (SCB): Fourier transform infrared absorption spectrometer [FT-I, manufactured by PerkinElmer Co., Ltd.]
R spectrometer 1760X]
It was determined from the intensity of the absorption band with respect to the bending vibration of the methyl group located at cm-1.

(9) Haze: A press sheet having a thickness of 200 μm was prepared using a compression molding machine (manufactured by Kansai Roll Co., Ltd.), and JIS was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd.). It was measured according to Z8722 (1982).

(10) Appearance after bacterial treatment: Press sheet similar to that used for haze measurement (width 80 mm × length 160 mm)
X 200 μm thick), a sealed container filled with pure water by heat sealing was prepared, and subjected to steam sterilization treatment at 110 ° C. for 40 minutes, and then the deformation state of the container surface was visually evaluated.

(11) Haze after sterilization treatment: A film was cut out from the sterilized container and the haze was measured.

(12) Drawdown property: Using a blow molding machine [3B-65 type, manufactured by Placo Co., Ltd.], using a converge type die [die core (20φ / 18φ)], a molding temperature of 170 ° C., and a screw rotation speed. It was evaluated as the time (second) until the resin reached 500 mm from the die exit under the condition of 10 rpm.

(13) Blow moldability: Sharkskin generation on the surface of the blow molded body was visually evaluated.

(14) Degree of cleanness: 0.1
After sufficiently washing with pure water (ultra pure water) filtered through a μm filter, the container was filled with pure water and sealed. This is 11
After performing a steam sterilization treatment at 0 ° C. for 40 minutes, the number of fine particles having a particle size of 2 μm or more [cleanliness (particles / ml)] present in the ultrapure water in the container was measured using a liquid fine particle counter (HIAC / R).
OYCO, series 4100). All operations were performed in a class 1000 clean room.

Table 1 shows Examples 1 to 8 and Comparative Examples 1 to
7 / ethylene / hexene-1 copolymer [AI]
([AI-1] to [AI-4]) and [AII]
([AII-1] to [AII-6]).

Table 2 shows that the ethylene / hexene-1 copolymer [ZI] obtained by a high-pressure ion polymerization method using a conventionally known Ziegler-type catalyst outside the claims used in Comparative Example 8
([ZI-1]) and [ZII] ([ZII-1])
The features of

Table 3 shows that the HP-LDPE [B] ([B1] to HP-LDPE) used in Examples 1 to 5 and Comparative Examples 1 to 10
[B3]).

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

[Table 3]

Examples 1 to 8 Table 4 shows the characteristics of the ethylene / hexene-1 copolymer compositions ([C1] to [C5]) of [C] used in Examples 1 to 7. The MFR and the amount of residual crystals in the table are those of the ethylene / hexene-1 copolymer [AI] and [AI] shown in Table 1.
I] was measured after melt granulation with a Labo Plastomill single screw extruder.

Table 5 shows the characteristics of the ethylene / hexene-1 copolymer composition ([C6]) of [C] used in Example 8. [C6] is obtained by simultaneously polymerizing ethylene / hexene-1 copolymers [AI] and [AII] in a single reactor. In addition, Table 5 shows that the ethylene / hexene-1 copolymer [A
After the polymerization of I] and [AII] in separate reactors, the characteristics of the melt-granulated ethylene / hexene-1 copolymer composition [C1] were exhibited. Since [C6] simultaneously performs the polymerization of [AI] and [AII], the individual ethylene / α-olefin copolymers ([AI] and [A
II]) cannot be evaluated, but [C
MFR, M _w / M _n , N value, and residual crystal amount, which were almost the same as those in [1].

Table 6 shows that [C] ([C1] to [C6])
2 shows the drawdown, γ _c , appearance of the molded article, haze, haze after sterilization, appearance after sterilization, and cleanliness of the composition composed of the composition consisting of and (B) ([B1] and [B2]).

[0074]

[Table 4]

[0075]

[Table 5]

[0076]

[Table 6]

Comparative Examples 1 to 8 Table 7 shows the characteristics of the ethylene / hexene-1 copolymer compositions ([D1] to [D7]) of [D] used in Comparative Examples 1 to 8. Tables 1 and 2 show the MFR and the amount of residual crystals in the table.
Was measured after melt-granulating the ethylene / hexene-1 copolymer [AI] or [ZI] and [AII] or [ZII] shown in Table 1 with a Labo Plastomill single screw extruder.

In Comparative Examples 1 to 5, ethylene /
Hexene-1 copolymer composition [D] ([D1] to [D1]
5]) and HP-LDPE [B1] used in Examples.

In Comparative Example 6, the same ethylene / hexene-1 copolymer composition [D] ([D
6]) and HP-LDPE [B] ([B1]), wherein the weight ratio of [D]: [B] is out of the claims.

In Comparative Example 7, the same ethylene / hexene-1 copolymer composition [D] ([D
6]) and HP-LDPE [B] ([B
3]).

In Comparative Example 8, an ethylene / hexene-1 copolymer comprising ethylene / hexene-1 copolymers ([ZI] and [ZII]) obtained by a high-pressure ionic polymerization method using a conventionally known Ziegler-type catalyst was used. Polymer composition [D] ([D
7]) and HP-LDPE [B1] used in Examples.

Table 8 shows that [D] ([D1] to [D7])
2 shows the drawdown, γ _c , appearance of the molded article, haze, haze after sterilization, appearance after sterilization, and cleanliness of the composition composed of the composition consisting of and (B) ([B1] and [B3]).

[0083]

[Table 7]

[0084]

[Table 8]

[0085]

As described above, the blow molding resin composition of the present invention has good blow moldability, is transparent, and has excellent sterilization heat resistance.

Accordingly, the present composition is a suitable material for blow-molded articles requiring transparency and sterilization heat resistance, for example, medical containers such as cosmetic containers and infusion bags.

[0087]

Claims (5)

[Claims] 1. An ethylene / α-olefin copolymer satisfying the following requirements (a) and (b): 190 ° C .;
A copolymer [AI] having a melt flow rate (hereinafter referred to as MFR) of 0.1 to 8 g / 10 min measured under a load of 16 kg and a copolymer [AII] having a MFR of 8 to 100 g / 10 min. And low-density polyethylene (hereinafter referred to as [B]) obtained by a high-pressure radical polymerization method satisfying the following requirements (c) and (d), and [AII] / [A
I] The weight ratio is 80/20 to 20/80, and the MFR ratio of the component [AII] and the component [AI] (MFRII / M
FRI) is in the range of 5-100, and ([AI] + [A
A resin composition for blow molding, wherein the weight ratio of [II]) / [B] is from 95/5 to 40/60. (A) a weight average molecular weight in the (M _w) and number average molecular weight ratio _{(M n) (M w /} M n) is 3 or less (b) a differential scanning calorimeter, and melted for 5 minutes at 200 ° C., then 10 The temperature was lowered to 30 ° C at a rate of
The temperature (T _m (° C.)) at the maximum peak position of the endothermic curve obtained when the temperature was raised at a rate of ° C./min and the number of short-chain branches (SCB) per 1000 carbon atoms determined from the measurement of the infrared absorption spectrum. Satisfies the relationship represented by equation (1). _Tm <−1.5 × SCB + 138 (1) (c) Density 0.910 to 0.935 g / cm ³ (d) MF measured at 190 ° C. under a load of 2.16 kg
R is 0.1-3g / 10min 2. [AI], [AI], [AI],
The resin composition for blow molding according to claim 1, wherein an ethylene / α-olefin copolymer composition [C] comprising [AII] is used. 3. An ethylene / α-olefin copolymer composition [C] having an MFR in the range of 0.3 to 10 g / 10 minutes measured at 190 ° C. under a load of 2.16 kg. The blow molding resin composition according to claim 2. 4. In a differential scanning calorimeter, 5 ° C. at 200 ° C.
Melting at 10 ° C./min to 30 ° C., and the residual crystallinity at 110 ° C. was 5% by weight or more, obtained from an endothermic curve obtained when the temperature was raised again at 10 ° C./min. The blow molding resin composition according to claim 2 or 3, wherein an ethylene / α-olefin copolymer composition [C] in a range of less than 40% by weight is used. 5. A medical container comprising the resin composition for blow molding according to claim 1.