JP3727634B2 - Retort food container - Google Patents

Description

  The present invention relates to polyethylene for medical containers and medical containers. More specifically, the present invention is excellent in hygiene, flexibility, impact resistance, transparency, heat resistance and the like, and is a medical container for containing blood, chemicals, and the like. The present invention relates to polyethylene suitable for a material and a medical container made of the polyethylene.

  Currently known medical containers include hard containers made of glass, polyethylene, polypropylene, etc., soft bags made of polyvinyl chloride containing a plasticizer, and the like. However, the above-mentioned hard container needs to introduce air using a vent needle or an infusion set with a vent when dripping the content liquid such as blood or drug solution. There is a risk of contamination. On the other hand, unlike the hard container described above, the soft bag is squeezed by the atmospheric pressure when the content liquid is dropped, so that the introduction of air is unnecessary and the hygiene is not necessary. There are advantages such as excellent, convenient transportation, and small waste. However, this soft bag has problems such as the plasticizer contained in polyvinyl chloride and the toxicity of residual monomers.

  On the other hand, for the purpose of improving flexibility, transparency, hygiene, etc., a medical bag using a polymer such as an ethylene / vinyl acetate copolymer or an elastomer as an intermediate layer has been proposed (Patent Document 1). . However, in this medical bag, there is a problem that wrinkles are generated in the bag during sterilization because the polymer used for the intermediate layer has poor heat resistance. In addition, conventional medical bags made from polyethylene are somewhat insufficient in heat resistance and cannot increase the sterilization temperature, so the sterilization process takes a long time or can be sterilized in a clean atmosphere. Inefficiency in the sterilization process, which must be performed, is a problem.

Therefore, hygiene and flexibility are good, transparency is not lost even if sterilization is performed at 115 ° C. for 30 minutes as shown in the Japanese Pharmacopoeia, and heat resistance is excellent, and wrinkles and deformation occur. The emergence of such medical containers made of polyethylene, such as medical bags made of multilayer films, medical bags made of single-layer films, and medical bottles made of single layers, is desired. The emergence of polyethylene to be used is desired.
JP 58-165866 A

  An object of the present invention is to solve the problems associated with the prior art as described above, which has good hygiene and flexibility and is sterilized at 115 ° C. for 30 minutes as shown in the Japanese Pharmacopoeia. Provides a polyethylene medical container that does not lose its transparency even when subjected to heat treatment, has excellent heat resistance, and does not cause wrinkles or deformation, and has excellent moldability for use in such a medical container. There is to do.

The retort food container according to the present invention is:
A copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms,
(I) the density is in the range of 0.915 to 0.940 g / cm ³ ;
(Ii) The melt flow rate at 190 ° C. and a load of 2.16 kg is in the range of 0.1 to 10.0 g / 10 minutes,
(Iii) Decane soluble component amount ratio (W) at room temperature and density (d) are W <80 × exp (−100 (d−0.88)) + 0.1
Satisfy the relationship indicated by
(Iv) Fluidity index (FI (1 / second)) defined by the shear rate when the shear stress at 190 ° C. of the molten polymer reaches 2.4 × 10 ⁶ dyne / cm ² , the melt flow The rate (MFR (g / 10 min)) is FI> 75 × MFR
Satisfy the relationship indicated by
(V) The melt tension (MT (g)) at 190 ° C. and the melt flow rate (MFR (g / 10 minutes)) are 5.5 × MFR ^−0.65 >MT> 2.2 × MFR ^−0.84
It is characterized by satisfying the relationship shown in.

Such polyethylene is
(A) a transition metal compound represented by the following formula (I) and ML _X (I)
(In the formula, M represents a transition metal selected from Group IVB of the periodic table, L represents a ligand coordinated to a transition metal atom, and at least two of these ligands L are methyl groups. And a substituted cyclopentadienyl group having only 2 to 5 substituents selected from an ethyl group, and the ligand L other than the substituted cyclopentadienyl group is a hydrocarbon group having 1 to 12 carbon atoms, An alkoxy group, an aryloxy group, a halogen atom, a trialkylsilyl group, or a hydrogen atom, and x represents the valence of the transition metal atom M.)
(B) It is obtained by copolymerizing ethylene and an α-olefin having 3 to 12 carbon atoms in the presence of an olefin polymerization catalyst containing an organoaluminum oxy compound.

  The polyethylene for medical containers according to the present invention has a narrow molecular weight distribution and composition distribution and a low raw polymer content. Furthermore, the moldability is excellent.

  Since the medical container according to the present invention is molded from polyethylene as described above, it has good hygiene and flexibility and can be sterilized at 115 ° C. for 30 minutes as shown in the Japanese Pharmacopoeia. Transparency is not lost, and furthermore, heat resistance is excellent, and wrinkles and deformation do not occur.

  Hereinafter, the polyethylene for medical containers and the medical container according to the present invention will be specifically described.

[Polyethylene for medical containers]
The polyethylene for medical containers according to the present invention is a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.

  In such polyethylene, the structural unit derived from ethylene is present in a proportion of 75 to 99% by weight, preferably 80 to 98% by weight, more preferably 85 to 96% by weight, and having 3 to 20 carbon atoms. The structural unit derived from α-olefin is desirably present in a proportion of 1 to 25% by weight, preferably 2 to 20% by weight, more preferably 4 to 15% by weight.

Here, the α-olefin having 3 to 20 carbon atoms includes propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, Examples include 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like.

The composition of polyethylene was determined by ¹³ C-NMR. That is, a ¹³ C-NMR spectrum of a sample in which about 200 mg of copolymer powder was uniformly dissolved in 1 ml of hexachlorobutadiene in a 10 mmφ sample tube, a measurement temperature of 120 ° C., a measurement frequency of 25.05 MHz, a spectrum width of 1500 Hz, It is determined by measuring under measurement conditions of a pulse repetition time of 4.2 sec and a pulse width of 6 μsec.

  The polyethylene for medical containers according to the present invention has the characteristics shown in the following (i) to (v).

(I) The density is 0.915 to 0.940 g / cm ³ , preferably 0.920 to 0.94.
0 g / cm ^3, more preferably from 0.920~0.935g / cm ^3.

  The density of polyethylene is measured at a temperature of 23 ± 0.1 ° C. according to D method of JIS K7112.

  (Ii) Melt flow rate at 190 ° C. and 2.16 kg load is 0.1 to 10.0 g / 10 min, preferably 0.5 to 8.0 g / 10 min, more preferably 1.0 to 5.0 g / min. It is in the range of 10 minutes.

  Melt flow rate is measured using polyethylene granulated pellets under conditions of 190 ° C. and 2.16 kg load according to ASTM D1238-65T.

The granulated pellet is 0.05 parts by weight of tri (2,4-di-t-butylphenyl) phosphate as a secondary antioxidant with respect to 100 parts by weight of powdered polyethylene, as a heat stabilizer. 0.1% by weight of n-octadecyl-3- (4′hydroxy-3 ′, 5′-di-t-butylphenyl) propinate is mixed with 0.05 part by weight of calcium stearate as a hydrochloric acid absorbent. Thereafter, it is prepared by melt extrusion at a set temperature of 180 ° C. using a conical tapered twin screw extruder manufactured by Harke.

(Iii) n-decane soluble component fraction (W (wt%)) and density (d (g / cm ³ ) at room temperature
))
W <80 × exp (−100 (d−0.88)) + 0.1
Preferably W <60 × exp (−100 (d−0.88)) + 0.1
More preferably, W <40 × exp (−100 (d−0.88)) + 0.1
The relationship indicated by is satisfied.

  It can be said that such polyethylene has a narrow composition distribution.

The n-decane soluble component fraction (W (% by weight)) is
W = n-decane soluble component amount / (n-decane insoluble component amount and soluble component amount) × 100%.

  The amount of polyethylene n-decane soluble component is about 3 g of polyethylene added to 450 ml of n-decane, dissolved at 145 ° C., cooled to 23 ° C., filtered to remove the n-decane insoluble part, and n-decane soluble from the filtrate. It is calculated | required by collect | recovering parts.

  The smaller the amount of soluble components, the narrower the composition distribution.

(Iv) Fluidity index (FI (1 / second)) defined by the shear rate when the shear stress at 190 ° C. of the molten polymer reaches 2.4 × 10 ⁶ dyne / cm ² , and the melt flow rate (MFR (g / 10 min))
FI> 75 × MFR
Preferably FI> 80 × MFR
More preferably, FI> 85 × MFR
The relationship indicated by is satisfied.

  If an attempt is made to produce polyethylene having a narrow composition distribution by the conventional technique, generally the molecular weight distribution is also narrowed at the same time, so that the fluidity is deteriorated and the FI is decreased. In the polyethylene of the present invention, since FI and MFR satisfy the above relationship, a low stress is maintained up to a high shear rate, and the moldability is good.

The flow index is defined as the shear rate at which the shear stress at 190 ° C. reaches 2.4 × 10 ⁶ dyne / cm ² . The flow index was determined by extruding the resin from the capillary while changing the shear rate and measuring the stress at that time. That is, using the same sample as the MT measurement, using a capillary flow characteristic tester manufactured by Toyo Seiki Seisakusho, the resin temperature is 190 ° C. and the shear stress range is about 5 × 10 ^{4 to} 3 × 10 ⁶ dyne / cm ² . Measured.

  In addition, it changes by changing the diameter of a nozzle (capillary) as follows by MFR (g / 10min) of polyethylene to measure.

1.0 mm when 10 ≧ MFR> 3
2.0 mm when 3 ≧ MFR> 0.8
3.0mm when 0.8 ≧ MFR
(V) The melt tension (MT (g)) at 190 ° C. and the melt flow rate (MFR (g / 10 minutes)) are 5.5 × MFR ^−0.65 >MT> 2.2 × MFR ^−0.84
5.0 × MFR ^-0.65 >MT> 2.5 × MFR ^-0.84
4.5 × MFR ^-0.65 >MT> 2.8 × MFR ^-0.84
The relationship indicated by is satisfied.

  Such an ethylene copolymer according to the present invention has a high melt tension (MT) and good moldability as compared with a conventional ethylene copolymer. If the MT is too high, skin roughness may occur during molding, and the appearance of the molded product may deteriorate.

  The melt tension is determined by measuring the stress when the molten polymer is stretched at a constant speed. That is, polyethylene granulated pellets were used as measurement samples, using a MT measuring machine manufactured by Toyo Seiki Seisakusho, resin temperature 190 ° C., extrusion speed 15 mm / min, winding speed 10-20 m / min, nozzle diameter 2.09 mmφ, nozzle It is performed under the condition of a length of 8 mm.

[catalyst]
The polyethylene according to the present invention as described above is, for example,
(A) a transition metal compound represented by the following general formula (I);
(B) In the presence of an olefin polymerization catalyst containing an organoaluminum oxy compound, ethylene and an α-olefin having 3 to 12 carbon atoms have a copolymer density of 0.915 to 0.00. It can manufacture by making it copolymerize so that it may become 940 g / cm < ³ >.

  The olefin polymerization catalyst and each catalyst component will be described below.

[(A) Transition metal compound]
The group IV transition metal compound (A) containing a ligand having a cyclopentadienyl skeleton is specifically a transition metal compound represented by the following formula (I).

ML _X (I)
(In the formula, M represents a transition metal selected from Group IVB of the periodic table, L represents a ligand coordinated to a transition metal atom, and at least two of these ligands L are methyl groups. And a substituted cyclopentadienyl group having only 2 to 5 substituents selected from an ethyl group, and the ligand L other than the substituted cyclopentadienyl group is a hydrocarbon group having 1 to 12 carbon atoms, An alkoxy group, an aryloxy group, a halogen atom, a trialkylsilyl group, or a hydrogen atom, and x represents the valence of the transition metal atom M.)
In the above general formula (I), M represents a transition metal atom selected from Group IVB of the periodic table, specifically zirconium, titanium or hafnium, preferably zirconium.

  L represents a ligand coordinated to the transition metal atom M, and at least two of these ligands L are substituted cyclopentadidi having only 2 to 5 substituents selected from a methyl group and an ethyl group. It is an enyl group, and each ligand may be the same or different. This substituted cyclopentadienyl group is a substituted cyclopentadienyl group having 2 or more substituents, and preferably a cyclopentadienyl group having 2 to 3 substituents. And more preferably a 1,3-substituted cyclopentadienyl group. Each substituent may be the same or different.

  In the above formula (I), the ligand L other than the substituted cyclopentadienyl group coordinated to the transition metal atom M is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a halogen atom. Represents a trialkylsilyl group or a hydrogen atom.

  Examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group, and more specifically, a methyl group, an ethyl group, and an n-propyl group. Alkyl groups such as isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group, decyl group; cyclopentyl group, cyclohexyl group, etc. Examples thereof include cycloalkyl groups; aryl groups such as phenyl groups and tolyl groups; and aralkyl groups such as benzyl groups and neophyll groups.

  Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a t-butoxy group, a pentoxy group, a hexoxy group, and an octoxy group. be able to.

  Examples of the aryloxy group include a phenoxy group.

  Halogen atoms are fluorine, chlorine, bromine and iodine. Examples of the trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, and a triphenylsilyl group.

As such a transition metal compound represented by the general formula (I),
Bis (dimethylcyclopentadienyl) zirconium dichloride,
Bis (diethylcyclopentadienyl) zirconium dichloride,
Bis (methylethylcyclopentadienyl) zirconium dichloride,
Bis (dimethylethylcyclopentadienyl) zirconium dichloride,
Bis (dimethylcyclopentadienyl) zirconium dibromide,
Bis (dimethylcyclopentadienyl) zirconium methoxychloride,
Bis (dimethylcyclopentadienyl) zirconium ethoxy chloride,
Bis (dimethylcyclopentadienyl) zirconium butoxychloride,
Bis (dimethylcyclopentadienyl) zirconium diethoxide,
Bis (dimethylcyclopentadienyl) zirconium methyl chloride,
Bis (dimethylcyclopentadienyl) zirconium dimethyl,
Bis (dimethylcyclopentadienyl) zirconium benzyl chloride,
Bis (dimethylcyclopentadienyl) zirconium dibenzyl,
Bis (dimethylcyclopentadienyl) zirconium phenyl chloride,
And bis (dimethylcyclopentadienyl) zirconium hydride chloride.

  In the above examples, the disubstituted product of the cyclopentadienyl ring includes 1,2- and 1,3-substituted products, and the trisubstituted product includes 1,2,3- and 1,2,4-substituted products. Including. In the present invention, a transition metal compound in which zirconium metal is replaced with titanium metal or hafnium metal in the above-described zirconium compound can be used.

Among these transition metal compounds represented by the general formula (I),
Bis (1,3-dimethylcyclopentadienyl) zirconium dichloride,
Bis (1,3-diethylcyclopentadienyl) zirconium dichloride,
Bis (1-methyl-3-ethylcyclopentadienyl) zirconium dichloride is particularly preferred.

  In the present invention, a transition metal compound component containing at least one transition metal compound represented by the general formula (I) is used as the transition metal compound component.

[(B) Organoaluminum oxy compound]
The organoaluminum oxy compound (B) may be a conventionally known benzene-soluble aluminoxane or a benzene-insoluble organoaluminum oxy compound as disclosed in JP-A-2-276807.

The above aluminoxane can be prepared, for example, by the following method.
(1) Compounds containing adsorbed water or salts containing water of crystallization, such as magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate, nickel sulfate hydrate, first cerium chloride hydrate, etc. A method of reacting adsorbed water or crystal water with an organoaluminum compound by adding an organoaluminum compound such as trialkylaluminum to the suspension of the hydrocarbon.

  (2) A method of allowing water, ice or water vapor to act directly on an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran.

  (3) A method of reacting an organotin oxide such as dimethyltin oxide or dibutyltin oxide with an organoaluminum compound such as trialkylaluminum in a medium such as decane, benzene, or toluene.

  In addition, this aluminoxane may contain a small amount of organometallic components. Further, after removing the solvent or the unreacted organoaluminum compound by distillation from the recovered solution of the above aluminoxane, it may be redissolved in the solvent.

Specific examples of organoaluminum compounds used in the preparation of aluminoxane include trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, trisec-butylaluminum, tritert- Trialkylaluminums such as butylaluminum, tripentylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum;
Tricycloalkylaluminum such as tricyclohexylaluminum, tricyclooctylaluminum;
Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diethylaluminum bromide, diisobutylaluminum chloride;
Dialkylaluminum hydrides such as diethylaluminum hydride, diisobutylaluminum hydride;
Dialkylaluminum alkoxides such as dimethylaluminum methoxide and diethylaluminum ethoxide;
Examples thereof include dialkylaluminum aryloxides such as diethylaluminum phenoxide.

  Of these, trialkylaluminum and trialkylaluminum are particularly preferred.

Further, as this organoaluminum compound, a general formula (i-C ₄ H ₉ ) _{x A y} (C ₅ H ₁₀ ) _z
(X, y, z are positive numbers and z ≧ 2x)
Isoprenylaluminum represented by the formula can also be used.

  The above organoaluminum compounds are used alone or in combination.

  Solvents used in the preparation of aluminoxane include aromatic hydrocarbons such as benzene, toluene, xylene, cumene, and cymene, aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane, hexadecane, and octadecane, Cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, cyclooctane and methylcyclopentane, petroleum fractions such as gasoline, kerosene and light oil or halides of the above aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons, among others , Hydrocarbon solvents such as chlorinated products and brominated products. In addition, ethers such as ethyl ether and tetrahydrofuran can also be used. Of these solvents, aromatic hydrocarbons are particularly preferred.

  The benzene-insoluble organoaluminum oxy compound has an Al component dissolved in benzene at 60 ° C. of 10% or less, preferably 5% or less, particularly preferably 2% or less in terms of Al atom, and is insoluble in benzene or Slightly soluble.

  The solubility of the organoaluminum oxy compound in benzene was determined by suspending the organoaluminum oxy compound corresponding to 100 milligrams of Al in 100 ml of benzene, and then mixing at 60 ° C. for 6 hours with stirring. Using a glass filter, hot filtration was performed at 60 ° C., and the solid part separated on the filter was washed four times with 50 ml of benzene at 60 ° C., and the amount of Al atoms present in the total filtrate ( x mmol) is determined by measuring (x%).

[(C) particulate carrier]
The catalyst for olefin polymerization used in the present invention comprises (A) the transition metal compound and (B).
A solid catalyst in which at least one of the organoaluminum oxy compounds is supported on a particulate carrier may be used.

The carrier (C) is an inorganic or organic compound, and a granular or particulate solid having a particle size of 10 to 300 μm, preferably 20 to 200 μm is used. Among these, as the inorganic carrier, porous oxides are preferable. Specifically, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, BaO, ThO _2, etc. or these Mixtures such as SiO ₂ —MgO, SiO ₂ —Al ₂ O ₃ , SiO ₂ —TiO ₂ , SiO ₂ —V ₂ O ₅ , SiO ₂ —Cr ₂ O ₃
And SiO ₂ —TiO ₂ —MgO. Of these, those containing as a main component at least one component selected from the group consisting of SiO ₂ and Al ₂ O ₃ are preferred.

The inorganic oxide includes a small amount of Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , MgCO ₃ , Na ₂ SO ₄ , Al ₂ (SO ₄ ) ₃ , BaSO ₄ , KNO ₃ , Mg (NO ₃ ). ₂ , Al (NO ₃ ) ₃ , N
Even if it contains carbonates, sulfates, nitrates and oxide components such as a ₂ O, K ₂ O, and Li ₂ O, there is no problem.

The properties of such a particulate carrier (C) vary depending on the type and production method, but the particulate carrier preferably used in the present invention has a specific surface area of 50 to 1000 m ² / g, preferably 1
It is desirable that it is 00-700 m < ² > / g and the pore volume is 0.3-2.5 cm < ³ > / g. The fine particle carrier is used after being calcined at 100 to 1000 ° C., preferably 150 to 700 ° C., if necessary.

Furthermore, examples of the particulate carrier that can be used in the present invention include granular or particulate solids of organic compounds having a particle size of 10 to 300 μm. These organic compounds include (co) polymers mainly composed of α-olefins having 2 to 14 carbon atoms such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, vinylcyclohexane, and styrene. Examples thereof include a polymer or copolymer as a main component.

[(D) Organoaluminum compound]
The catalyst for olefin polymerization used in the production of polyethylene according to the present invention is formed from the above (A) transition metal compound and (B) organoaluminum oxy compound, and (C) a particulate carrier, if necessary. Depending on (D), an organoaluminum compound may be used.

  Examples of the organoaluminum compound (D) used as needed include an organoaluminum compound represented by the following general formula (II).

R ¹ _n AlX _3-n (II)
(In the formula, R ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, X represents a halogen atom or a hydrogen atom, and n is 1 to 3).
In the general formula (II), R ¹ is a hydrocarbon group having 1 to 12 carbon atoms, such as an alkyl group, a cycloalkyl group, or an aryl group. Specifically, a methyl group, an ethyl group, n-propyl group, isopropyl group, isobutyl group, pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group and the like.

  Specific examples of such organoaluminum compounds include the following compounds.

Trialkylaluminums such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, tri-2-ethylhexylaluminum;
Alkenyl aluminum such as isoprenyl aluminum;
Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride, dimethylaluminum bromide;
Alkylaluminum sesquichlorides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum sesquibromide;
Alkylaluminum dihalides such as methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride, ethylaluminum dibromide;
Alkyl aluminum hydrides such as diethyl aluminum hydride and diisobutyl aluminum hydride.

Moreover, the compound represented by the following general formula (III) can also be used as the organoaluminum compound (D).

R ¹ _n AlY _3-n (III)
(In the formula, R ¹ represents the same hydrocarbon as R ¹ in the general formula (II), Y represents an —OR ² group, —
OSiR ³ ₃ group, —OAlR ⁴ ₂ group, —NR ⁵ ₂ group, —SiR ⁶ ₃ group or —N (R ⁷ ) AlR ⁸ ₂
N is 1 to ² , R ² , R ³ , R ⁴ and R ⁸ are methyl, ethyl, isopropyl, isobutyl, cyclohexyl, phenyl, etc., and R ⁵ is a hydrogen atom , Methyl group, ethyl group, isopropyl group, phenyl group, trimethylsilyl group and the like, and R ⁶ and R ⁷ are methyl group, ethyl group and the like. )
As such an organoaluminum compound, specifically, the following compounds are used.

(1) Compounds represented by R ¹ _n Al (OR ² ) _3-n , such as dimethylaluminum methoxide, diethylaluminum ethoxide, diisobutylaluminum methoxide,
(2) Compounds represented by R ¹ _n Al (OSiR ³ ₃ ) _3-n , for example, Et ₂ Al (OSi Me ₃ ), (iso-Bu) ₂ Al (OSiMe ₃ ), (iso-Bu) ₂ A
l (OSiEt ₃ ) and the like;
(3) a compound represented by R ¹ _n Al (OAlR ⁴ ₂ ) _3-n , such as Et ₂ AlOAlEt ₂ , (iso-Bu) ₂ AlOAl (iso-Bu) _2, etc .;
(4) Compounds represented by R ¹ _n Al (NR ⁵ ₂ ) _3-n , such as Me ₂ AlNEt ₂ , Et ₂ AlNHMe, Me ₂ AlNHEt, Et ₂ AlN (SiM
e ₃ ) ₂ , (iso-Bu) ₂ AlN (SiMe ₃ ) ₂ etc .;
(5) a compound represented by R ¹ _n Al (SiR ⁶ ₃ ) _3-n , such as (iso-Bu) ₂ AlSi Me ₃ ;
(6) A compound represented by R ¹ _n Al (N (R ⁷ ) AlR ⁸ ₂ ) _3-n , such as Et ₂ AlN (Me) AlEt ₂ ,
(Iso-Bu) ₂ AlN (Et) Al (iso-Bu) _{2 and the} like.

Among the organoaluminum compounds represented by the general formulas (II) and (III), the general formulas R ¹ ₃ Al, R ¹ _n Al (OR ² ) _{3 -n} , R ¹ _n Al (OAlR ⁴ ₂ ) ₃ A compound represented by _-n is preferable, and a compound in which R is an isoalkyl group and n = 2 is particularly preferable.

[Catalyst preparation]
The olefin polymerization catalyst comprises (A) the transition metal compound (component (A)) and (
It can be prepared by contacting B) an organoaluminum oxy compound (component (B)), if necessary, (C) a particulate carrier, and (D) an organoaluminum compound (component (D)). The contact order of the components at this time is arbitrarily selected, but the fine particle carrier (C) and the component (B) are mixed and contacted, then the component (A) is mixed and contacted, and further, the component ( D) is preferably mixed and contacted.

  The above-mentioned components can be contacted in an inert hydrocarbon solvent. Specifically, as the inert hydrocarbon medium, propane, butane, pentane, hexane, heptane, octane, decane, dodecane, kerosene and other fats are used. Aromatic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; Aromatic hydrocarbons such as benzene, toluene and xylene; Halogenated hydrocarbons such as ethylene chloride, chlorobenzene and dichloromethane, or mixtures thereof Can be mentioned.

Component (A), component (B), when mixed contacting the component (D) and optionally particulate carrier (C), component (A) particulate carrier (C) 1 g per usually 5 × 10 ^- It is used in an amount of ^{6 to} 5 × 10 ⁻⁴ mol, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ mol, and the concentration of component (A) is about 10 ⁻⁴ to 2 × 10 ⁻² mol / liter, preferably Is in the range of 2 × 10 ⁻⁴ to 10 ⁻² mol / liter. The atomic ratio (Al / transition metal) of the component (B) aluminum and the transition metal in the component (A) is usually 10 to 500, preferably 20 to 200. The atomic ratio (Al-d / Al-b) of the aluminum atom (Al-d) of the component (D) and the aluminum atom (Al-b) of the component (B) used as required is usually 0.02 to 3, preferably in the range of 0.05 to 1.5. The mixing temperature for mixing and contacting the component (A), the component (B), the fine particle carrier (C) and, if necessary, the component (D) is usually −50 to 150 ° C., preferably −20 to 120 ° C. The contact time is 1 minute to 50 hours, preferably 10 minutes to 25 hours.

The olefin polymerization catalyst obtained as described above contains 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ gram atoms, preferably 10 transition metal atoms derived from the component (A) per 1 g of the particulate carrier (C). ^{-5 to} 2 × 10 ^-4 grams of atoms are supported, and aluminum atoms derived from component (B) and component (D) per gram of particulate carrier (C) are 10 ^{-3 to} 5 × 10 ^-2 grams. It is desirable to be supported in an amount of atoms, preferably 2 × 10 ⁻³ to 2 × 10 ⁻² gram atoms.

  The catalyst used for the production of polyethylene is obtained by prepolymerizing an olefin in the presence of the component (A), the component (B), the fine particle carrier (C) and, if necessary, the component (D). It may be a prepolymerization catalyst. The prepolymerization is performed by introducing an olefin into an inert hydrocarbon solvent in the presence of the component (A), the component (B), the fine particle carrier (C) and, if necessary, the component (D). It can be carried out.

Examples of the olefin used in the prepolymerization include ethylene and an α-olefin having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene. 1-decene, 1-dodecene, 1-tetradecene and the like. Among these, ethylene used in the polymerization or a combination of ethylene and α-olefin is particularly preferable.

In the prepolymerization, the component (A) is usually used in an amount of 10 ⁻⁶ to 2 × 10 ⁻² mol / liter, preferably 5 × 10 ⁻⁵ to 10 ⁻² mol / liter. A) is usually used in an amount of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ mol, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ mol, per 1 g of the particulate carrier (C). The atomic ratio (Al / transition metal) of the component (B) aluminum and the transition metal in the component (A) is usually 10 to 500, preferably 20 to 200. The atomic ratio (Al-d / Al-b) of the aluminum atom (Al-d) of the component (D) and the aluminum atom (Al-b) of the component (B) used as required is usually 0.02 to 3, preferably in the range of 0.05 to 1.5. The prepolymerization temperature is -20 to 80 ° C, preferably 0 to 60 ° C, and the prepolymerization time is 0.5 to 100 hours, preferably about 1 to 50 hours.

The olefin polymer produced by the prepolymerization is desirably in an amount of 0.1 to 500 g, preferably 0.2 to 300 g, more preferably 0.5 to 200 g per 1 g of the fine particle carrier (C). In the prepolymerization catalyst, the component (A) per 1 g of the fine particle support (C) is about 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ gram atoms, preferably 10 ⁻⁵ to 2 × 10 ⁻ as transition metal atoms. Aluminum atoms (Al) supported in an amount of ⁴ gram atoms and derived from component (B) and component (D) are in molar ratio (Al / M) to transition metal atoms (M) derived from component (A). , 5 to 200, preferably 10 to 150.

  The prepolymerization can be performed either batchwise or continuously, and can be performed under reduced pressure, normal pressure, or increased pressure. In the prepolymerization, the preliminary viscosity [η] measured in decalin at least 135 ° C. in the presence of hydrogen is in the range of 0.2 to 7 dl / g, preferably 0.5 to 5 dl / g. It is desirable to produce a polymer.

The polyethylene of the present invention comprises ethylene and an α-olefin having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 4 in the presence of the olefin polymerization catalyst as described above. -Methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene.

  In the present invention, the copolymerization of ethylene and α-olefin is performed in a gas phase or a slurry liquid phase. In slurry polymerization, an inert hydrocarbon may be used as a solvent, or olefin itself may be used as a solvent.

  Specific examples of the inert hydrocarbon solvent used in the slurry polymerization include aliphatic hydrocarbons such as butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane, and octadecane; cyclopentane, methylcyclopentane, cyclohexane, Examples thereof include alicyclic hydrocarbons such as cyclooctane; aromatic hydrocarbons such as benzene, toluene and xylene; petroleum fractions such as gasoline, kerosene and light oil. Of these inert hydrocarbon media, aliphatic hydrocarbons, alicyclic hydrocarbons, petroleum fractions and the like are preferable.

When the slurry polymerization method or the gas phase polymerization method is performed, the olefin polymerization catalyst as described above usually has a transition metal atom concentration in the polymerization reaction system of 10 ⁻⁸ to 10 ⁻³ gram atom / liter, It is preferably used in an amount of 10 ⁻⁷ to 10 ⁻⁴ gram atom / liter.

  Moreover, you may add the organoaluminum oxy compound and / or organoaluminum compound (D) similar to a component (B) in this superposition | polymerization. At this time, the atomic ratio (Al / M) of the aluminum atom (Al) derived from the organoaluminum oxy compound and the organoaluminum compound to the transition metal atom (M) derived from the transition metal compound (A) is 5 to 300. , Preferably 10 to 200, more preferably 15 to 150.

  When carrying out the slurry polymerization method, the polymerization temperature is usually in the range of −50 to 100 ° C., preferably from 0 to 90 ° C. When carrying out the gas phase polymerization method, the polymerization temperature is usually from 0 to 120 degreeC, Preferably it is the range of 20-100 degreeC.

The polymerization pressure is usually from atmospheric pressure 100 kg / cm ^2, and preferably a pressurized condition of to 50 kg / cm ^2, the polymerization is a batch, semi-continuous, be carried out by any of the methods of continuous it can.

Furthermore, the polymerization can be performed in two or more stages having different reaction conditions.
[Medical container]
The medical container according to the present invention is a bag made of a multilayer film, a bag made of a single layer film, a bottle made of a single layer, or the like. At least one layer of the multilayer film, the single layer film, or the single layer bottle is made of the polyethylene described above. It is formed with.

  The medical container according to the present invention can be produced by a water-cooled or air-cooled inflation method, a T-die method, a dry lamination method, an extrusion lamination method, a hollow molding method, or the like.

  As a method for forming a medical bag, an inflation method and a co-extrusion T-die method are preferable from the viewpoint of hygiene and economy, and a hollow molding method is preferable as a method for forming a medical bottle.

  The medical container of the present invention has a thickness in the range of 0.05 to 1.00 mm, preferably 0.1 to 0.7 mm, more preferably 0.15 to 0.3 mm. If the thickness of the container is 0.05 mm or more, the impact resistance is good and there is no practical problem.

  In addition, the container for retort foodstuffs can be manufactured with the linear polyethylene used by this invention. This container for retort food has very good transparency after retort treatment (sterilization treatment), has impact resistance and flexibility, and has excellent heat resistance.

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

  In addition, the physical property evaluation of polyethylene and the physical property evaluation of the hollow molded product and the film were performed as follows.

[Molecular weight distribution (Mw / Mn)]
It was measured by Waters GPC model ALC-GPC-150C. The measurement conditions are PSK-GMH-HT manufactured by Toyo Soda Co., Ltd. as a column, an orthodichlorobenzene (ODCB) solvent, 140 ° C.

[Maximum peak temperature (Tm) by DSC]
This was carried out using a DSC-7 type apparatus manufactured by PerkinElmer. The temperature (Tm) at the maximum peak position in the endothermic curve is about 5 mg of sample packed in an aluminum pan, heated to 200 ° C. at 10 ° C./min, held at 200 ° C. for 5 min, and then cooled to room temperature at 10 ° C./min Then, the temperature is obtained from an endothermic curve when the temperature is raised at 10 ° C./min.

[Haze (Transparency)]
The haze used as an index of the transparency of a hollow molded product and a film that was retorted at 115 ° C. for 30 minutes was measured according to ASTM D-1003-61.

[Light transmittance in water (transparency)]
The light transmittance in water of the hollow molded article and film which were retorted at 115 ° C. for 30 minutes was measured in accordance with the Japanese Pharmacopoeia Plastic Container Test Method.

[appearance]
The appearance of hollow molded products and films that have been retorted at 115 ° C for 30 minutes is observed with the naked eye, and the appearance evaluation when deformation is observed is indicated by x, and the appearance evaluation when deformation is not observed is indicated by ○. did.

[Young's modulus (flexibility)]
The Young's modulus was measured in accordance with JIS K 6781.

[Production Example 1]
Production of polyethylene (A-1);
[Preparation of catalyst]
10 kg of silica dried at 250 ° C. for 10 hours was suspended in 154 liters of toluene, and then cooled to 0 ° C. Thereafter, 57.5 liters of a methylaminooxane solution in toluene (Al = 1.33 mol / liter) was added dropwise over 1 hour. At this time, the temperature in the system was kept at 0 ° C. Subsequently, the mixture was reacted at 0 ° C. for 30 minutes, then heated to 95 ° C. over 1.5 hours, and reacted at that temperature for 20 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by a decantation method. The solid component thus obtained was washed twice with toluene and then resuspended in 100 liters of toluene. Into this system, 16.8 liters of a toluene solution of bis (1,3-dimethylcyclopentadienyl) zirconium dichloride (Zr = 27.0 mmol / liter) was appropriately reduced at 80 ° C. over 30 minutes, and further at 80 ° C. The reaction was performed for 2 hours. Thereafter, the supernatant was removed and washed twice with hexane to obtain a solid catalyst containing 3.5 mg of zirconium per gram.

[Preparation of prepolymerization catalyst]
By adding 870 g of the solid catalyst obtained above and 260 g of 1-hexene to 87 liters of hexane containing 2.5 mol of triisobutylaluminum, and preliminarily polymerizing ethylene at 35 ° C. for 5 hours, A prepolymerized catalyst in which 10 g of polyethylene was prepolymerized was obtained.

[Polymerization]
Using a continuous fluidized bed gas phase polymerization apparatus, copolymerization of ethylene and 1-hexene was carried out at a total pressure of 20 kg / cm ² -G and a polymerization temperature of 80 ° C. In order to maintain a constant gas composition during the polymerization, the prepolymerized catalyst prepared above was continuously supplied at a rate of 0.33 mmol / h in terms of zirconium atom and triisobutylaluminum at a rate of 10 mmol / h. Hexene, hydrogen, and nitrogen were continuously supplied (gas composition: 1-hexene / ethylene = 0.02, hydrogen / ethylene = 1.2 × 10 ⁻³ , ethylene concentration = 70%).

The yield of the obtained polyethylene (A-1) is 60 kg / hr, the density is 0.923 g / cm ³ , the MFR is 1.5 g / 10 min, and the decane-soluble part at room temperature is 0.00. It was 41 parts by weight. The properties of the obtained polyethylene (A-1) are shown in Table 1.

[Production Example 2]
In the preparation of the catalyst component of Production Example 1, in place of the toluene solution of bis (1,3-dimethylcyclopentadienyl) zirconium dichloride, the toluene solution of bis (1,3-dimethylcyclopentadienyl) zirconium dichloride (Zr 28.1 mmol / liter).
Polymerization was conducted in the same manner as in Production Example 1 except that 9 liters and 10.9 liters of a toluene solution of bis (1,3-n-butylmethylcyclopentadienyl) zirconium dichloride (Zr; 34.0 mmol / liter) were used. A catalyst was obtained.

[polymerization]
Density and MFR were adjusted as shown in Table 1, and polyethylene (A-2) was obtained in the same manner as in Production Example 1 except that the olefin polymerization catalyst was used. The properties of the obtained polyethylene (A-2) are shown in Table 1.

[Production Example 3]
[Preparation of Olefin Polymerization Catalyst]
In a nitrogen stream, 10 mol of commercially available anhydrous magnesium chloride was suspended in 50 liters of dehydrated and purified hexane, and 60 mol of ethanol was added dropwise over 1 hour with stirring, followed by reaction at room temperature for 1 hour.

  Next, 27 mol of diethylaluminum chloride was added dropwise to the reaction solution at room temperature, and the mixture was stirred for 1 hour. Subsequently, 100 mol of titanium tetrachloride was added, and then the system was heated to 70 ° C. and reacted while stirring for 3 hours. The produced solid part was separated by decantation, washed repeatedly with purified hexane, and then made into a hexane suspension.

[Production of polyethylene (A-3)]
A 200 liter continuous polymerization reactor was continuously supplied with dehydrated and purified solvent hexane at 80 liter / hr, and the supported catalyst was converted into titanium at 1.2 mmol / hr continuously. hr, 1-butene 13.0 kg / hr, hydrogen continuously supplied at a rate of 100 liters / hr, polymerization temperature 145 ° C., total pressure 30 kg / cm ² -G, residence time 1 hour, concentration of copolymer relative to solvent hexane The copolymer was prepared under the conditions of 12 g / l.

The polyethylene (A-3) obtained as described above has a density of 0.920 g / cm ³ , a melt flow rate of 2.0 g / 10 minutes, and a decane-soluble part at 23 ° C. of 10% by weight. %, Mw / Mn was 2.8, and Tm was 116.2 ° C. Table 1 shows the properties of the obtained polyethylene (A-3).

  The polyethylene (A-1) obtained in Production Example 1 was pelletized with an extruder and a hollow molded product was molded under the following molding conditions.

[Manufacture of hollow molded products]
Using polyethylene blow molding machine made of polyethylene, a hollow molded product with a thickness of 400 μm is molded under the conditions of a cylinder temperature of 160 to 180 ° C., a die temperature of 180 ° C., a mold temperature of 20 ° C., and a blow pressure of 3 kg / cm ² -G. did.

  About the obtained hollow molded article, after retorting at 115 ° C. for 30 minutes, haze, light transmittance in water, appearance and Young's modulus were measured and evaluated by the methods described above. The results are shown in Table 2.

  The polyethylene (A-2) obtained in Production Example 2 was pelletized with an extruder, and a hollow molded article was molded and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 1]
[Manufacture of hollow molded products]
The polyethylene (A-3) obtained in Production Example 2 was molded under the same conditions as in Example 1 to obtain a hollow molded product.

  The obtained hollow molded article was subjected to a retort treatment at 115 ° C. for 30 minutes, and then the haze, the light transmittance in water, the appearance, and the Young's modulus were measured or evaluated by the methods described above. The results are shown in Table 2.

[Production of film]
The polyethylene (A-1) produced in Production Example 1 is formed into a film by a cast film molding machine manufactured by Modern Corp. under conditions of a cylinder temperature of 180 to 220 ° C., a die temperature of 220 ° C., and a roll temperature of 30 ° C. Film was obtained.

The obtained film was subjected to a retort treatment at 115 ° C. for 30 minutes, and then haze, light transmittance in water, appearance, and Young's modulus were measured or evaluated by the methods described above. Table 3 shows the results.
Shown in

[Production of film]
In Example 3, a film having a thickness of 200 μm was obtained in the same manner as in Example 3 except that polyethylene (A-2) produced in Production Example 2 was used instead of polyethylene (A-1).

  The obtained film was subjected to a retort treatment at 115 ° C. for 30 minutes, and then haze, light transmittance in water, appearance, and Young's modulus were measured or evaluated by the methods described above. The results are shown in Table 3.

[Comparative Example 2]
[Production of film]
In Example 3, a film having a thickness of 200 μm was obtained in the same manner as in Example 3 except that polyethylene (A-3) produced in Comparative Example 1 was used instead of polyethylene (A-1).

  The obtained film was subjected to a retort treatment at 115 ° C. for 30 minutes, and then haze, light transmittance in water, appearance, and Young's modulus were measured or evaluated by the methods described above. The results are shown in Table 3.

[Production of film]
The polyethylene (A-1) produced in Production Example 1 was molded by the air-cooled inflation method under the following molding conditions to produce a film having a thickness of 50 μm and a width of 450 mm.

[Molding condition]
Molding machine: Placo LM 65mmφ inflation molding machine (Placo, high-pressure low-density polyethylene resin specification)
Screw: L / D = 28, CR = 2.8, with intermediate mixing Dies: 200mmφ (diameter), 1.2mm (lip width)
Air ring: 2 gap type Molding temperature: 200 ℃
Take-off speed: 18 m / min The obtained film was subjected to a retort treatment at 115 ° C. for 30 minutes, and then the haze, the light transmittance in water, the appearance and the Young's modulus were measured or evaluated by the methods described above. Table 4 shows the results.
Shown in

[Production of film]
A film having a thickness of 50 μm was obtained in the same manner as in Example 5 from the polyethylene (A-2) produced in Production Example 2.

  The obtained film was subjected to a retort treatment at 115 ° C. for 30 minutes, and then haze, light transmittance in water, appearance, and Young's modulus were measured or evaluated by the methods described above. The results are shown in Table 4.

[Comparative Example 3]
[Production of film]
A film having a thickness of 50 μm was obtained from the polyethylene (A-3) produced in Comparative Example 1 in the same manner as in Example 5.

  The obtained film was subjected to a retort treatment at 115 ° C. for 30 minutes, and then haze, light transmittance in water, appearance, and Young's modulus were measured or evaluated by the methods described above.

  The results are shown in Table 4.

Claims (2)

A copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms,
(I) the density is in the range of 0.915 to 0.940 g / cm ³ ;
(Ii) The melt flow rate at 190 ° C. and a load of 2.16 kg is in the range of 0.1 to 10.0 g / 10 minutes,
(Iii) Decane soluble component amount ratio (W) at room temperature and density (d) are W <80 × exp (−100 (d−0.88)) + 0.1
Satisfy the relationship indicated by
(Iv) a fluidity index (FI (1 / second)) defined by the shear rate at which the shear stress at 190 ° C. of the molten polymer reaches 2.4 × 10 ⁶ dyne / cm ² ;
Melt flow rate (MFR (g / 10 min)) is FI> 75 × MFR
Satisfy the relationship indicated by
(V) The melt tension (MT (g)) at 190 ° C. and the melt flow rate (MFR (g / 10 minutes)) are 5.5 × MFR ^−0.65 >MT> 2.2 × MFR ^−0.84
A container for retort food, which is made of polyethylene that satisfies the relationship represented by The polyethylene is
(A) a transition metal compound represented by the following general formula (I);
ML _X (I)
(In the formula, M represents a transition metal selected from Group IVB of the periodic table, L represents a ligand coordinated to a transition metal atom, and at least two of these ligands L are methyl groups. And a substituted cyclopentadienyl group having only 2 to 5 substituents selected from an ethyl group, and the ligand L other than the substituted cyclopentadienyl group is a hydrocarbon group having 1 to 12 carbon atoms, An alkoxy group, an aryloxy group, a halogen atom, a trialkylsilyl group, or a hydrogen atom, and x represents the valence of the transition metal atom M.)
(B) The retort food according to claim 1, which is obtained by copolymerizing ethylene and an α-olefin having 3 to 12 carbon atoms in the presence of an olefin polymerization catalyst containing an organoaluminum oxy compound. Container.