JP5283891B2 - Polyethylene resin composition for clean container packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyethylene resin composition for clean container packaging which is reduced in the amount of fine particles and eluting components, is suppressed in the occurrence of metal corrosion in a molding machine, etc., and the discoloration of the molded article, and to provide a container packaging excellent in cleanness. <P>SOLUTION: The invention relates to the polyethylene resin composition for clean container packaging having 890-975 kg/m<SP>3</SP>of density, 0.01-30 g/10 min of melt flow rate and as additives, containing only an inorganic solid, which substantially has basic points, in an amount of 5-500 weight ppm per 1 kg of the polyethylene resin. The invention also relates to the clean container packaging produced by molding the resin composition. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention has few fine particles and elution components, suppresses corrosion of metals such as molding machines, suppresses discoloration of molded containers and films, and further suppresses corrosion and discoloration of contents filled in containers or packaged with films. The present invention relates to a polyethylene resin composition. The polyethylene resin composition of the present invention is suitable as a resin material for containers and packaging that requires cleanliness.

  In the field of electronic materials such as semiconductors and hard disks, various defects occur due to the adhering of contaminants to products or components, resulting in a decrease in yield and reliability. In particular, with the remarkable development of the electronic material field in recent years, as products have become more precise, trace amounts of contamination have become a problem. Concerning these types of contamination, contamination from packaging materials when packing and storing high-purity chemicals or components used in the manufacturing process, and containers and components for filling high-purity chemicals, is also considered a problem. It has become.

  Examples of high-purity chemicals include wafer cleaning / etching, wiring / insulating film etching, jig cleaning, developer, resist dilution, resist stripper, and drying applications such as sulfuric acid, hydrochloric acid, nitric acid, Hydrofluoric acid, ammonium fluoride, hydrogen peroxide solution, 2-propanol, xylene, TMAH (tetramethylammonium hydroxide), methanol, acetic acid, phosphoric acid, aqueous ammonia, PGMEA (propylene glycol methyl ether acetate), DMSO ( Dimethyl sulfoxide), NMP (N-methylpyrrolidinone), ECA (ethyl cyanoacrylate), ethyl lactate and the like are used.

  Conventionally, polyethylene resins have been used as these materials for containers for high-purity chemicals in terms of chemical resistance, impact resistance, price, and the like. However, conventional containers made of polyethylene resin have a problem of contamination of contents by chemicals eluted from the resin, deteriorated products, etc., and have a limit for high-purity chemical containers. That is, with the miniaturization of VLSI, the metal impurity concentration has conventionally been required to be 1 PPB or less, but now it is required to be 0.1 PPB or less. Conventionally, fine particles having a size of 0.5 μm or more have been a problem, but depending on the field, strict quality is demanded such that fine particles having a size of 0.2 μm or more are 100 particles / ml or less. I'm not satisfied. On the other hand, polyethylene resins are required to have characteristics required for general containers, for example, long-term characteristics such as ESCR (environmental stress crack resistance), impact strength, which is an index of safety when dropped. ing.

A clean polyethylene resin container is disclosed in which the generation of fine particles having a particle diameter of 0.2 μm or more is 500 pieces / ml or less (see, for example, Patent Document 1). There was a fear that the number of occurrences was not sufficiently suppressed.
Further, polyethylene resins and containers for large-sized high-purity chemical containers are disclosed (for example, see Patent Document 2 and Patent Document 3). These resins and containers reduce the amount of neutralizing agents such as fatty acid metal salts by reducing the ash and chloride ions contained in the polyethylene resin, resulting in corrosion of molded machines and metal molds and molded products. It is very excellent in suppressing discoloration. However, the amount of neutralizing agent used is not sufficient for the chloride ions contained in the polyethylene resin, and if it is molded for a long time, corrosion of the metal in the molding machine and mold occurs. In addition, there is a risk that the contents may be corroded or discolored by chloride ions generated from the molded container and packaging. Moreover, only the quantity of the additive containing the neutralizing agent added to a polyethylene resin is prescribed | regulated as ash content, and the kind and addition amount of the neutralizing agent and additive to be used were not mentioned. Further, long-term characteristics such as ESCR, which is a characteristic required for polyethylene resin, have not been defined at all.

  On the other hand, related parts such as semiconductors and hard disks, and packaging materials for precision machinery, etc., are known to be affected by submicron-level particles, volatile components, and eluted ions, which have a significant impact on yield. There is a need for materials. In practice, additive-free polyethylene bags are widely used from the standpoints of cleanliness, physical properties, and price.

  When polyethylene is used as a clean container packaging material, it has been practiced to add no additives such as neutralizing agents and heat stabilizers in order to avoid degradation of cleanliness due to elution of the additives (for example, (See Patent Document 6). However, in the present invention, since the catalyst for polymerizing polyethylene is a metallocene catalyst and does not contain chloride ions in the catalyst, it is not necessary to add an additive for neutralizing chloride ions. In addition, in polyethylene resin compositions using Ziegler-based catalysts, systems that do not contain additives for neutralizing chloride ions derived from the catalyst are widely known, but are used with significant problems. . This problem is that the standard of cleanliness is achieved by adding no additives, but the chloride ions present as hydrogen chloride derived from Ziegler-based catalysts cause the product to be used in extruders, molds, and suppliers. This is due to the fact that it frequently corrodes and the resin and molded containers and packages are reddish and sometimes cause red discoloration with a strength that cannot be put on the market. The cause of red discoloration is not clear, but it is presumed that chloride ions derived from Ziegler catalysts react with titanium catalyst residues and additive residues in the system to give a red color. Normally, neutralization of chloride ions using a metal stearate such as calcium stearate as a neutralizing agent will not cause corrosion or red coloration, but these neutralizing agents generate particles in clean container packaging applications. As a source, the degree of cleanliness decreases and cannot be used for these purposes.

  Under such circumstances, a technique using hydrotalcite as a neutralizing agent is known (for example, see Patent Document 4). However, in order to maintain moldability, it is essential to use hydrotalcite in combination with a fatty acid metal salt or the like, and such a system cannot achieve cleanliness. Moreover, in the invention (for example, refer patent document 5) regarding the resin composition for films, the hydrotalcite was only added in order to improve the moisture retention of a film, and was not used as a neutralizing agent.

JP-A-7-257540 Japanese Patent Laid-Open No. 11-80449 JP 2003-96133 A JP-A-5-295185 JP 2000-109623 A International Publication No. 2003/031512 Pamphlet

The object of the present invention is that there are few fine particles and elution components derived from the polyethylene resin and additives, suppress discoloration of the molded product, and further, the molding machine and mold by chloride ions contained in the polyethylene resin, and further, the product after packaging It is providing the polyethylene resin composition for clean container packaging which can suppress corrosion and deterioration.
In this specification, the term “container packaging” is used as a term meaning “container and packaging material”.
In this specification, “clean” is used as a term that means that when a liquid is contained in a container and packaging, the constituent components of the container and packaging are less likely to be mixed or eluted as fine particles in the liquid.

As a result of intensive studies to solve the above-mentioned problems, the present inventor did not impair the physical properties of the polyethylene resin, cause no discoloration of the molded product, by substantially adding only an inorganic solid having a base point, and The present inventors have found that it is possible to suppress the corrosion and deterioration of the molding machine and the mold, as well as the contents after packaging.
That is, this invention is a polyethylene resin composition as described below, and a clean container packaging using the same.

(1) A polyethylene resin composition used as a material constituting an innermost layer in contact with at least the contents of a clean container package that protects the contents from contamination, and includes the following (A), (B), (C) And a polyethylene resin composition for packaging clean containers , which satisfies the requirements of (D) .
(A) Density (JIS K7112-1999) is 890 kg / ^{m 3} or more 975 kg / ^{m 3} or less.
(B) The melt flow rate (JIS K7210-1999, code D) is 0.01 g / 10 min or more and 30 g / 10 min or less.
(C) As an additive, it contains only an inorganic solid having a base point substantially, and the amount of the additive is 5 ppm by weight to 500 ppm by weight with respect to 1 kg of polyethylene resin.
(D) A polyethylene resin is obtained using a Ziegler catalyst.
(2) A polyethylene resin composition used as a material constituting the innermost layer in contact with at least the contents of a clean container package that protects the contents from contamination, and the following (A), (B), (C) And a polyethylene resin composition for lean container packaging, characterized by satisfying the requirements of (D).
(A) Density (JIS K7112-1999) is 890 kg / ^{m 3} or more 975 kg / ^{m 3} or less.
(B) The melt flow rate (JIS K7210-1999, code D) is 0.01 g / 10 min or more and 30 g / 10 min or less.
(C) As an additive, it contains only an inorganic solid having a base point substantially, and the amount of the additive is 5 ppm by weight to 500 ppm by weight with respect to 1 kg of polyethylene resin.
(D) A polyethylene resin is obtained using a chromium-based catalyst.
( 3 ) The polyethylene resin composition for packaging clean containers according to (1) or (2) above, wherein the inorganic solid is a hydrotalcite compound.
( 4 ) Clean container packaging formed by molding the polyethylene resin composition for clean container packaging according to any one of (1) to (3 ) above.

  According to the present invention, there are few fine particles and elution components derived from the polyethylene resin and additives, suppressing discoloration of the molded product, and corrosion of the molding machine and mold by the chloride ions contained in the polyethylene resin, and further the contents after packaging -The polyethylene resin composition for clean container packaging which can suppress deterioration can be provided.

The present invention will be specifically described below.
The polyethylene resin composition in the present invention is suitable for a polyethylene resin composition produced using a Ziegler-based catalyst, but depends on the polyethylene resin composition produced using a chromium-based catalyst or a metallocene (single site) catalyst or the catalyst system. The present invention can also be applied to a polyethylene resin composition obtained by mixing two or more polyethylene resin compositions.

  The Ziegler catalyst in the present invention is an olefin polymerization catalyst containing a titanium chloride compound and an alkylaluminum compound as essential components (see, for example, P.836 of the Riken Dictionary 5th edition (Iwanami Shoten)). In the present invention, the Ziegler catalyst production method is not particularly limited, but is preferably a Ziegler catalyst produced by the following production method.

That is, the Ziegler catalyst in the present invention comprises a solid catalyst component [A] and an organometallic compound component [B], and the solid catalyst component [A] is an inert hydrocarbon solvent represented by the following general formula (1). A carrier (A-3) prepared by the reaction of a soluble organomagnesium compound (A-1) and a chlorinating agent (A-2) represented by the following general formula (2) has the following general formula (3 It is preferable that it is a Ziegler catalyst for olefin polymerization produced by carrying | supporting the titanium compound (A-4) represented by this.
(M ¹ ) _a (Mg) _b (R ¹ ) _c (R ² ) _d (OR ³ ) _e (1)
(In the formula, M ¹ is a metal atom other than magnesium belonging to the group consisting of Group 1, Group 2, Group 12, and Group 13 of the Periodic Table, and R ¹ and R ² each have 2 to 20 carbon atoms. R ³ is a hydrocarbon group having 1 to 20 carbon atoms, and a, b, c, d, and e are real numbers that satisfy the following relationship: 0 ≦ a, 0 <b , 0 ≦ c, 0 ≦ d, 0 ≦ e, 0 <c + d, 0 ≦ e / (a + b) ≦ 2, f × a + 2b = c + d + e (where f is the valence of M ¹ ))
H _h SiCl _i R ⁴ _{(4- (h + i))} (2)
(Wherein R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers satisfying the following relationship: 0 <h, 0 <i, 0 <h + i ≦ 4)
Ti (OR ⁵ ) _j X _(4-j) (3)
(In the formula, j is a real number of 0 or more and 4 or less, R ⁵ is a hydrocarbon group of 1 to 20 carbon atoms, and X is a halogen atom.)

  First, the organomagnesium compound (A-1) will be described. (A-1) is shown as a complex form of organomagnesium soluble in an inert hydrocarbon solvent, but includes all dihydrocarbylmagnesium compounds and complexes of this compound with other metal compounds Is. The symbols a, b, c, d and e in the general formula 1 satisfy the relational expression f × a + 2b = c + d + e, which indicates the stoichiometry between the valence of the metal atom and the substituent.

In the above formulae, the hydrocarbon groups represented by R ¹ to R ² are each an alkyl group, a cycloalkyl group or an aryl group, for example, methyl, ethyl, propyl, butyl, propyl, hexyl, octyl, decyl, cyclohexyl , A phenyl group, etc., preferably R ¹ and R ² are each an alkyl group. When a> 0, as the metal atom M ¹ , metal atoms other than magnesium belonging to the group consisting of Group 1, Group 2, Group 12 and Group 13 of the Periodic Table can be used. For example, lithium, sodium Potassium, beryllium, zinc, boron, aluminum and the like, and aluminum, boron, beryllium, and zinc are particularly preferable.

No particular limitation on the ratio b / a of magnesium to metal atom M ^1, but more preferably preferably 0.1 to 30, 0.5 to 10. Further, when a certain organomagnesium compound in which a = 0 is used, for example, when R ¹ is 1-methylpropyl or the like, it is soluble in an inert hydrocarbon solvent, and such a compound is also used in the present invention. Gives favorable results. In the general formula 1, it is recommended that R ¹ and R ² when a = 0 is ^{one of} the following three groups (1), (2), and (3).

(1) At least one of R ¹ and R ² is a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably R ¹ and R ² both have 4 to 6 carbon atoms, At least one is a secondary or tertiary alkyl group.
(2) R ¹ and R ² are alkyl groups having different carbon numbers, preferably R ¹ is an alkyl group having 2 or 3 carbon atoms, and R ² is an alkyl group having 4 or more carbon atoms. about.
(3) At least one of R ¹ and R ² is a hydrocarbon group having 6 or more carbon atoms, preferably an alkyl group in which the sum of carbon atoms contained in R ¹ and R ² is 12 or more.

  Hereinafter, these groups are specifically shown. As the secondary or tertiary alkyl group having 4 to 6 carbon atoms in (1), 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 2-methylbutyl, 2-ethylpropyl, 2 , 2-dimethylpropyl, 2-methylpentyl, 2-ethylbutyl, 2,2-dimethylbutyl, 2-methyl-2-ethylpropyl group and the like are used, and 1-methylpropyl group is particularly preferable. Next, in (2), examples of the alkyl group having 2 or 3 carbon atoms include ethyl, 1-methylethyl, propyl group and the like, and the ethyl group is particularly preferable. Examples of the alkyl group having 4 or more carbon atoms include butyl, pentyl, hexyl, heptyl, octyl group and the like, and butyl and hexyl groups are particularly preferable. Furthermore, examples of the hydrocarbon group having 6 or more carbon atoms in (3) include hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl group and the like. Among the hydrocarbon groups, an alkyl group is preferable, and among the alkyl groups, hexyl and octyl groups are particularly preferable. In general, an increase in the number of carbon atoms contained in an alkyl group facilitates dissolution in an inert hydrocarbon solvent. However, the use of an unnecessarily long alkyl group is not preferred in terms of handling because the solution viscosity increases. The organomagnesium compound is used as an inert hydrocarbon solution, but the solution can be used as long as a trace amount of Lewis basic compounds such as ethers, esters and amines are contained or remain in the solution. The inert hydrocarbon solvent in the present invention includes aliphatic hydrocarbons such as pentane, hexane and heptane, aromatic hydrocarbons such as benzene and toluene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. .

Next, the alkoxy group (OR ³ ) will be described. The hydrocarbon group represented by R ³ is preferably an alkyl group or aryl group having 1 to 12 carbon atoms, and particularly preferably an alkyl group or aryl group having 3 to 10 carbon atoms. Specifically, for example, methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 1,1-dimethylethyl, pentyl, hexyl, 2-methylpentyl, 2-ethylbutyl, 2-ethylpentyl, Examples include 2-ethylhexyl, 2-ethyl-4-methylpentyl, 2-propylheptyl, 2-ethyl-5-methyloctyl, octyl, nonyl, decyl, phenyl, naphthyl groups, and the like. Butyl, 1-methylpropyl, 2 -Methylpentyl and 2-ethylhexyl groups are particularly preferred.

In the present invention, the synthesis method of (A-1) is not particularly limited, but from the general formulas R ¹ MgX and R ¹ ₂ Mg (R ¹ has the above-mentioned meaning and X is a halogen atom). And an organometallic compound belonging to the group consisting of the general formulas M ¹ R ² _f and M ¹ R ² _(f-1) H (M ¹ , R ² and f are as defined above) In an inert hydrocarbon solvent, the reaction is carried out at a temperature of 25 ° C. or more and 150 ° C. or less, and if necessary, an alcohol having a hydrocarbon group represented by R ³ (R ³ has the above-mentioned meaning) or A method of reacting with an alkoxymagnesium compound having a hydrocarbon group represented by R ³ and / or an alkoxyaluminum compound that is soluble in an inert hydrocarbon solvent is preferred.

Among these, when reacting an organomagnesium compound soluble in an inert hydrocarbon solvent with an alcohol, the order of the reaction is not particularly limited, and a method of adding alcohol to the organomagnesium compound, organomagnesium in the alcohol Either a method of adding a compound or a method of adding both at the same time can be used. In the present invention, the reaction ratio between the organomagnesium compound soluble in the inert hydrocarbon solvent and the alcohol is not particularly limited, but as a result of the reaction, the alkoxy group-containing organomagnesium compound in the resulting alkoxy group-containing organomagnesium compound contains all of the alkoxy groups. The molar composition ratio e / (a + b) is 0 ≦ e / (a + b) ≦ 2, and preferably 0 ≦ e / (a + b) <1.
Next, the chlorinating agent (A-2) will be described. (A-2) is represented by the general formula 2, and at least one is a silicon chloride compound having a Si-H bond.
H _h SiCl _i R ⁴ _{(4- (h + i))} (2)
(Wherein R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers satisfying the following relationship: 0 <h, 0 <i, 0 <h + i ≦ 4)

The hydrocarbon group represented by R ⁴ in the general formula (2) is an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group such as methyl, ethyl, propyl, 1-methylethyl. , Butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, phenyl group and the like. Among them, an alkyl group having 1 to 10 carbon atoms is preferable, and 1 to 1 carbon atoms such as methyl, ethyl, propyl and 1-methylethyl groups are preferable. More preferred is an alkyl group of 3. H and i are numbers greater than 0 satisfying the relationship of h + i ≦ 4, and i is preferably 2 or more and 3 or less.

These compounds include HSiCl ₃ , HSiCl ₂ CH ₃ , HSiCl ₂ C ₂ H ₅ , HSiCl ₂ (C ₃ H ₇ ), HSiCl ₂ (2-C ₃ H ₇ ), HSiCl ₂ (C ₄ H ₉ ), HSiCl ₂ (C ₆ H ₅ ), HSiCl ₂ (4-Cl—C ₆ H ₄ ), HSiCl ₂ (CH═CH ₂ ), HSiCl ₂ (CH ₂ C ₆ H ₅ ), HSiCl ₂ (1-C ₁₀ H ₇ ), HSiCl ₂ (CH ₂ CH═CH ₂ ), H ₂ SiCl (CH ₃ ), H ₂ SiCl (C ₂ H ₅ ), HSiCl (CH ₃ ) ₂ , HSiCl (C ₂ H ₅ ) ₂ , HSiCl ( CH ₃ ) (2-C ₃ H ₇ ), HSiCl (CH ₃ ) (C ₆ H ₅ ), HSiCl (C ₆ H ₅ ) _{2 and the} like, and these compounds or these compounds A silicon chloride compound composed of a mixture of two or more selected from the above is used. Among these, trichlorosilane, monomethyldichlorosilane, dimethylchlorosilane, and ethyldichlorosilane are preferable, and trichlorosilane and monomethyldichlorosilane are more preferable.

  Next, the reaction between (A-1) and (A-2) will be described. In the reaction, (A-2) is preliminarily treated with an inert hydrocarbon solvent, chlorinated hydrocarbons such as 1,2-dichloroethane, o-dichlorobenzene and dichloromethane, or ether-based media such as diethyl ether and tetrahydrofuran, or these It is preferable to use after diluting with a mixed medium, and an inert hydrocarbon solvent is more preferable in view of the performance of the catalyst. Although there is no restriction | limiting in particular in the reaction ratio of (A-1) and (A-2), The silicon atom contained in (A-2) with respect to 1 mol of magnesium atoms contained in (A-1) is 0.01. It is preferably 100 mol or less, more preferably 0.1 mol or more and 10 mol or less.

  The reaction method of (A-1) and (A-2) is not particularly limited, and a method of simultaneous addition in which (A-1) and (A-2) are reacted while being simultaneously introduced into the reactor, A method in which (A-1) is introduced into the reactor after A-2) is charged into the reactor in advance, or (A-2) is charged into the reactor after (A-1) is charged into the reactor in advance. Although any method of the method of introducing may be sufficient, the method of introducing (A-1) into a reactor after charging (A-2) into a reactor in advance is preferable. The carrier (A-3) obtained by the above reaction is preferably separated by filtration or decantation and then thoroughly washed with an inert hydrocarbon solvent to remove unreacted products or by-products. .

  Although there is no restriction | limiting in particular about the reaction temperature of (A-1) and (A-2), It is preferable that it is 25 to 150 degreeC, It is more preferable that it is 40 to 150 degreeC, 50 degreeC More preferably, it is 150 degrees C or less. In the method of simultaneous addition in which (A-1) and (A-2) are simultaneously introduced into the reactor and reacted, the temperature of the reactor is adjusted to a predetermined temperature in advance, The reaction temperature is preferably adjusted to the predetermined temperature by adjusting the temperature to the predetermined temperature. In the method in which (A-1) is introduced into the reactor after (A-2) is charged in the reactor in advance, the temperature of the reactor charged with the silicon chloride compound is adjusted to a predetermined temperature, and the organomagnesium The reaction temperature is preferably adjusted to a predetermined temperature by adjusting the temperature in the reactor to a predetermined temperature while introducing the compound into the reactor. In the method of introducing (A-2) into the reactor after charging (A-1) into the reactor in advance, the temperature of the reactor charged with (A-1) is adjusted to a predetermined temperature, and (A The reaction temperature is adjusted to a predetermined temperature by adjusting the temperature in the reactor to a predetermined temperature while introducing -2) into the reactor.

The reaction of (A-1) and (A-2) can also be performed in the presence of a solid. This solid may be either an inorganic solid or an organic solid, but it is preferable to use an inorganic solid. The following are mentioned as an inorganic solid.
(I) Inorganic oxides (ii) Inorganic carbonates, silicates, sulfates (iii) Inorganic hydroxides (iv) Inorganic halides (v) Double salts, solid solutions or mixtures comprising (i) to (iv)

Specific examples of the inorganic solid include silica, alumina, silica / alumina, hydrated alumina, magnesia, tria, titania, zirconia, calcium phosphate / barium sulfate, calcium sulfate, magnesium silicate, magnesium / calcium, aluminum silicate [(Mg / Ca ) O · Al ₂ O ₃ · 5SiO ₂ · nH ₂ O], potassium silicate · aluminum [K ₂ O · 3Al ₂ O ₃ · 6SiO ₂ · 2H ₂ O], magnesium iron silicate [(Mg · Fe) 2SiO ₄ ] , Aluminum silicate [Al ₂ O ₃ .SiO ₂ ], calcium carbonate, magnesium chloride, magnesium iodide, and the like are preferable, and silica, silica / alumina, and magnesium chloride are particularly preferable. The specific surface area of the inorganic solid is preferably 20 m ² / g or more, particularly preferably 90 m ² / g or more.

Next, the titanium compound (A-4) will be described. In the present invention, (A-4) is a titanium compound represented by the aforementioned general formula 3.
Ti (OR ⁵ ) _j X _(4-j) (3)
(Wherein j is a real number of 0 or more and 4 or less, R ⁶ is a hydrocarbon group of 1 to 20 carbon atoms, and X is a halogen atom.)
Examples of the hydrocarbon group represented by R ⁵ include aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, decyl, and allyl groups, cyclohexyl, and 2-methylcyclohexyl. , An alicyclic hydrocarbon group such as cyclopentyl group, and an aromatic hydrocarbon group such as phenyl and naphthyl group. An aliphatic hydrocarbon group is preferable. Examples of the halogen represented by X include chlorine, bromine and iodine, with chlorine being preferred. (A-4) selected from the above can be used as a mixture of two or more.

Although there is no restriction | limiting in particular in the usage-amount of (A-4), 0.01-20 is preferable by molar ratio with respect to the magnesium atom contained in a support | carrier (A-3), and 0.05-10 is especially preferable.
Although there is no restriction | limiting in particular about the reaction temperature of (A-4), It is preferable to carry out in 25 to 150 degreeC.
In the present invention, there is no particular limitation on the method of supporting (A-4) with respect to (A-3), and there is a method of reacting excess (A-4) with (A-3) or a third component. A method of efficiently supporting (A-4) by use may be used, but a method of supporting by (A-4) and an organometallic compound (A-5) is preferred.

Next, the organometallic compound (A-5) will be described. As (A-5), what is represented by the following general formula (4) and general formula (5) is preferable.
(M ¹ ) _a (Mg) _b (R ¹ ) _c (R ² ) _d Y _e (4)
(Wherein M ¹ , R ¹ , R ² , a, b, c, d, e are as described above, Y is alkoxy, siloxy, allyloxy, amino, amide, —N═C—R ⁶ , R ⁷ , —SR ⁸ (wherein R ⁶ , R ⁷ and R ⁸ represent a hydrocarbon group having 1 to 20 carbon atoms. When e is 2 or more, Y may be different from each other), any one of β-keto acid residues, and a, b, c, d and e are real numbers satisfying the following relationship: 0 ≦ a, 0 <b, 0 ≦ c, 0 ≦ d, 0 ≦ e , 0 <c + d, 0 ≦ e / (a + b) ≦ 2, f × a + 2b = c + d + e (where f is the valence of M ¹ ))
M ² R ⁹ _k Q _(m−k) (5)
(Wherein M ² is a metal atom belonging to the group consisting of Group 1, Group 2, Group 12, Group 13 of the Periodic Table, R ⁹ is a hydrocarbon group having 1 to 20 carbon atoms, and Q is OR ¹⁰ , OSiR ¹¹ R ¹² R ¹³ , NR ¹⁴ R ¹⁵ , SR ¹⁶ and a group belonging to the group consisting of halogen, R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ are hydrogen atoms Or a hydrocarbon group, k is a real number greater than 0, and m is the valence of M ² )

Hereinafter, the organometallic compounds represented by the general formula (4) and the general formula (5) are referred to as (A-5a) and (A-5b), respectively.
First, (A-5a) will be described.
The amount of (A-5a) used is preferably 0.1 or more and 10 or less in terms of the molar ratio of magnesium atoms contained in (A-5a) to titanium atoms contained in (A-4). More preferably, it is 5 or less. Although there is no restriction | limiting in particular about the temperature of reaction with (A-4) and (A-5a), It is preferable that it is -80 degreeC or more and 150 degrees C or less, and it is the range of -40 degreeC or more and 100 degrees C or less. Further preferred.
Although there is no restriction | limiting in particular about the density | concentration at the time of use of (A-5a), It is preferable that it is 0.1 mol / l or more and 2 mol / l or less on the basis of the magnesium atom contained in (A-5a). More preferably, it is 5 mol / l or more and 1.5 mol / l or less. In addition, it is preferable to use an inert hydrocarbon solvent for the dilution of (A-5a).

There is no restriction | limiting in particular in the addition order of (A-4) and (A-5a) with respect to (A-3), (A-5a) is added following (A-4), (A-5a) is followed. (A-4) and (A-4) and (A-5a) can be added at the same time, but (A-4) and (A-5a) can be added simultaneously. The method of adding is preferable. The reaction between (A-4) and (A-5a) is carried out in an inert hydrocarbon solvent, but it is preferable to use an aliphatic hydrocarbon solvent such as hexane or heptane. The catalyst thus obtained is used as a slurry solution using an inert hydrocarbon solvent.
Next, (A-5b) will be described. (A-5b) is an organometallic compound represented by the following general formula 5.

In the above general formula (5), M ² is a metal atom belonging to the group consisting of Group 1, Group 2, Group 12, Group 13 of the Periodic Table, for example, lithium, sodium, potassium, beryllium, magnesium , Boron, aluminum, zinc and the like, magnesium, boron and aluminum are preferable. The hydrocarbon group represented by R ⁹ is an alkyl group, a cycloalkyl group or an aryl group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a cyclohexyl group and a phenyl group. It is preferably a group.

Q represents a group belonging to the group consisting of OR ¹⁰ , OSiR ¹¹ R ¹² R ¹³ , NR ¹⁴ R ¹⁵ , SR ¹⁶ and halogen, and R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ Is a hydrogen atom or a hydrocarbon group, and Q is preferably a halogen atom. As the compound name of (A-5b), methyllithium, butyllithium, methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, butylmagnesium chloride, butylmagnesium bromide , Butyl magnesium iodide, dibutyl magnesium, dihexyl magnesium, triethyl boron, trimethyl aluminum, dimethyl aluminum bromide, dimethyl aluminum chloride, dimethyl aluminum methoxide, methyl aluminum dichloride, methyl aluminum sesquichloride, triethyl aluminum, diethyl aluminum chloride, diethyl aluminum bromide , Diethyla Minium ethoxide, ethylaluminum dichloride, ethylaluminum sesquichloride, tripropylaluminum, tributylaluminum, tri (2-methylpropyl) aluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, etc. preferable. Moreover, it is also possible to mix and use these compounds. k is a real number larger than 0, and is preferably a real number larger than 0.5.

The amount of (A-5b) used is preferably 0.1 or more and 10 or less in terms of a molar ratio of M ³ atoms contained in (A-5b) to titanium atoms contained in (A-4). More preferably, it is 5 or more and 5 or less. Although there is no restriction | limiting in particular about the temperature of reaction of (A-4) and (A-5b), It is preferable that it is 20 to 150 degreeC, and it is more preferable that it is 40 to 100 degreeC.
No particular limitation is imposed on the concentration at the time of use (A-5b), preferably not more than (A-5b) INCLUDED ^{M 2} atomic basis in 0.1 mol / l or more 2 mol / l, 0 More preferably, it is 5 mol / l or more and 1.5 mol / l or less. In addition, it is preferable to use an inert hydrocarbon solvent for the dilution of (A-5b).

There is no restriction | limiting in particular in the addition method of (A-4) and (A-5b) with respect to (A-3), First, (A-4) is added, and this is followed by the method of adding (A-5b) First, (A-5b) is added, and then either (A-4) is added, or (A-4) and (A-5b) are added simultaneously. However, it is preferable to add (A-5b) first and then add (A-4). The reaction between (A-4) and (A-5b) is carried out in an inert hydrocarbon solvent, but it is preferable to use an aliphatic hydrocarbon solvent such as hexane or heptane. The catalyst thus obtained is used as a slurry solution using an inert hydrocarbon solvent.
When (A-5b) is used, (A-3) is reacted with alcohol in advance before adding (A-4) and (A-5b) to (A-3). Further, it is preferable to react with (A-5b).

  As the alcohol, those having 1 to 10 carbon atoms are preferable, and specifically, methanol, ethanol, propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 1-methyl. -2-propanol, 1-pentanol, 1-hexanol, 1-octanol, 2-ethyl-1-hexanol, decanol, and the like. As the alcohol, those having 2 to 6 carbon atoms are more preferable, and ethanol, propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 1-methyl-2-propanol, 1 More preferred are pentanol and 1-hexanol. Although there is no restriction | limiting in particular about the usage-amount of alcohol, It is preferable that it is 0.01-1 in molar ratio with respect to the magnesium atom contained in (A-3), and it is 0.05-0.5. Further preferred. Although there is no restriction | limiting in particular about the density | concentration at the time of use of alcohol, It is preferable to use it diluting 0.1M or more and 2M or less using an inert hydrocarbon solvent. Although there is no restriction | limiting in particular about the temperature of reaction with (A-3) and alcohol, It is preferable that it is 25 to 150 degreeC, and it is more preferable that it is 40 to 80 degreeC.

The reaction between (A-3) and (A-5b) after reacting with alcohol will be described. Although there is no restriction | limiting in particular about the usage-amount of (A-5b), It is preferable that it is 0.1 or more and 10 or less by molar ratio with respect to the used alcohol, and it is still more preferable that it is 0.5 to 5 times. No particular limitation is imposed on the concentration at the time of use (A-5b), preferably not more than (A-5b) INCLUDED ^{M 2} atomic basis in 0.1 mol / l or more 2 mol / l, 0 More preferably, it is 5 mol / l or more and 1.5 mol / l or less. In addition, it is preferable to use an inert hydrocarbon solvent for the dilution of (A-5b). Although there is no restriction | limiting in particular about the temperature of reaction with (A-3) and (A-5b) after making it react with alcohol, It is preferable that it is 25 to 150 degreeC, and it is 40 to 80 degreeC. More preferably it is.

  Next, the organometallic compound component [B] in the present invention will be described. The solid catalyst component [A] of the present invention becomes a highly active polymerization catalyst when combined with the organometallic compound component [B]. The organometallic compound component [B] is preferably a compound containing a metal belonging to the group consisting of Group 1, Group 2, Group 12 and Group 13 of the Periodic Table, particularly organoaluminum compounds and / or Or an organomagnesium compound is preferable.

As the organoaluminum compound, a compound represented by the following general formula (6) is preferably used alone or in combination.
AlR ¹⁷ _n Z _(3-n) (6)
Wherein R ¹⁷ is a hydrocarbon group having 1 to 20 carbon atoms, Z is a group belonging to the group consisting of hydrogen, halogen, alkoxy, allyloxy and siloxy groups, and n is a number of 2 to 3. In the above general formula 6, the hydrocarbon group having 1 to 20 carbon atoms represented by R ¹⁷ includes aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons. Trialkylaluminum such as aluminum, triethylaluminum, tripropylaluminum, tributylaluminum, tri (2-methylpropyl) aluminum, tripentylaluminum, tri (3-methylbutyl) aluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, Diethylaluminum chloride, ethylaluminum Aluminum halide compounds such as mudichloride, bis (2-methylpropyl) aluminum chloride, ethylaluminum sesquichloride, diethylaluminum bromide, alkoxyaluminum compounds such as diethylaluminum ethoxide, bis (2-methylpropyl) aluminum butoxide, dimethylhydrosiloxy Siloxyaluminum compounds such as aluminum dimethyl, ethylmethylhydrosiloxyaluminum diethyl, ethyldimethylsiloxyaluminum diethyl and mixtures thereof are preferred, and trialkylaluminum compounds are particularly preferred.

The organomagnesium compound is preferably an organomagnesium compound that is soluble in the inert hydrocarbon solvent represented by the above general formula 1.
(M ¹ ) _a (Mg) _b (R ¹ ) _c (R ² ) _d (OR ³ ) _e Expression 1
(In the formula, M ¹ is a metal atom other than magnesium belonging to the group consisting of Group 1, Group 2, Group 12, and Group 13 of the Periodic Table, and R ¹ and R ² each have 2 to 20 carbon atoms. R ³ is a hydrocarbon group having 1 to 20 carbon atoms, and a, b, c, d, and e are real numbers that satisfy the following relationship: 0 ≦ a, 0 <b , 0 ≦ c, 0 ≦ d, 0 ≦ e, 0 <c + d, 0 ≦ e / (a + b) ≦ 2, f × a + 2b = c + d + e (where f is the valence of M ¹ ))

This organomagnesium compound is shown as a complex form of organomagnesium soluble in an inert hydrocarbon solvent, but encompasses all dialkylmagnesium compounds and complexes of this compound with other metal compounds. is there. Since this organomagnesium compound is preferably a compound having high solubility in an inert hydrocarbon solvent, b / a is preferably 0.5 or more and 10 or less, and more preferably a compound in which M ¹ is aluminum.

  The method for adding the solid catalyst component [A] and the organometallic compound component [B] to the polymerization system under the polymerization conditions is not particularly limited, and both may be added separately to the polymerization system. You may add in a polymerization system, after making both react. Moreover, there is no restriction | limiting in particular in the ratio of both to combine, but it is preferable that organometallic compound [B] is 1 to 3000 millimoles with respect to 1 g of solid catalyst component [A].

Next, the density of the polyethylene resin composition in the present invention will be described. In the present invention, the density of the polyethylene resin composition has been measured in accordance with JIS K7112-1999, it is 890 kg / ^{m 3} or more 975 kg / ^{m 3} or less. If the density of the polyethylene resin composition is 890 kg / m ³ or more, the low-density component to be eluted is sufficiently small, and if the density is 975 kg / m ³ or less, the long-term characteristics of the polyethylene resin composition are sufficiently high. The density of the polyethylene resin composition is preferably 910 kg / m ³ or more and 970 kg / m ³ or less, more preferably 910 kg / m ³ or more and 940 kg / m ³ or less, and more preferably 915 kg / m ³ or more. It is particularly preferred that it is 935 kg / m ³ or less. On the other hand, more preferably as the container for high purity chemicals is less than 940 kg / ^{m 3} or more 970 kg / ^{m 3,} more preferably at most 945 kg / ^{m 3} or more ^{970kg / m 3, 950kg / m} 3 or more 965 kg / it is especially preferred m ³ or less.

  Next, the molecular weight of the polyethylene resin composition in the present invention will be described. In the present invention, the melt flow rate (MFR) (JIS K7210-1999, code D) of the polyethylene resin composition is 0.01 g / 10 min or more and 30 g / 10 min or less. If the MFR of the polyethylene resin composition is 0.01 g / 10 min or more, the moldability is good, and if the MFR is 30 g / 10 min or less, the mechanics of the packaging material produced using the resin composition Properties such as ESCR and impact strength are sufficiently high. Regarding the packaging bag, the MFR of the polyethylene resin composition is preferably from 0.1 g / 10 min to 10 g / 10 min, and more preferably from 0.3 g / 10 min to 5 g / 10 min. On the other hand, for a high-purity chemical container, the MFR of the polyethylene resin composition is preferably 0.03 g / 10 min or more and 10 g / 10 min or less, and 0.05 g / 10 min or more and 2 g / 10 min or less. More preferably, it is 0.05 g / 10 min or more and 0.6 g / 10 min or less.

In the case of a polyethylene resin produced using a Ziegler catalyst, the polyethylene resin component is preferably a polyethylene resin produced using a Ziegler catalyst by a multistage polymerization method comprising at least a low molecular weight component and a high molecular weight component. When produced by a polymerization method, the melt flow rate (JIS K7210-1999, code D) of the low molecular weight component is 3 g / 10 min to 50 g / 10 min, and the density (JIS K7112-1999) is 960 kg / m ^3. An ethylene homopolymer of 974 kg / m ³ or less or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and the mass fraction of the high molecular weight component to the polyethylene resin is 0.40. It is preferable to be 0.46 or less in order to maintain clean properties and impart good moldability. There.

  Next, in the present invention, the molecular weight of 1000 or less as measured by gel permeation chromatography (GPC) is preferably 0.5 w% or less, more preferably 0.4 w% or less, and even more preferably 0.3 w% or less. The amount indicates the amount of low molecular weight components and wax contained in polyethylene, and the low molecular weight components and wax are eluted in high-purity chemicals to cause fine particles and deteriorate cleanliness. When the amount is 0.5 w% or less, the cleanliness can be satisfied.

  In the present invention, the additive contains only an inorganic solid having a basic point substantially, and the amount of the additive is 5 ppm by weight to 500 ppm by weight, preferably 20 ppm by weight to 300 ppm by weight, based on 1 kg of polyethylene. More preferably, it is 25 weight ppm or more and 200 weight ppm or less, and particularly preferably 150 weight ppm or more and 200 weight ppm or less. By making it 5 ppm by weight or more, it can absorb the chloride ions contained in the polyethylene resin, suppress the reaction with the content liquid and the occurrence of rust which is metal corrosion of the equipment and can suppress the red discoloration of the resin, By setting the amount to 500 ppm by weight or less, the additive does not elute and the cleanliness does not deteriorate.

  Containing only an inorganic solid having a basic point as an additive means that an additive that may elute or adhere to the contents other than the inorganic solid having a basic point is not arbitrarily added. . In the present invention, all the additives that may be dissolved or adhered to the contents are included, specifically, a heat stabilizer, an antioxidant, a weathering stabilizer, an antistatic agent, a lubricant, an antiblocking agent and the like. can give. On the other hand, pigments, light-shielding agents, etc. that do not elute or adhere to the contents can be used as long as the desired effects are not impaired.

The base point in the present invention is a site that exhibits Lewis basicity, that is, a site capable of adsorbing the compound by providing the compound with a lone pair. The inorganic solid having a base point is an element belonging to Group 1 of the Periodic Table and an oxide of an element that is a metal, an element belonging to Group 2 of the Periodic Table, and an oxidation of an element that is a metal. An oxide of an element that belongs to Group 4 of the periodic table and is a metal, an oxide of an element that is a metal, a metal oxide that is an element that belongs to Group 1 of the periodic table and carries an element that is a metal, and periodic table Oxides of elements that are elements belonging to Group 2 and are metals, metal oxides that are elements belonging to Group 13 of the periodic table supporting KF, and elements that are metals, and the aforementioned oxides Complex oxides between them, elements belonging to Group 1 of the periodic table, and carrying hydroxides of elements that are metals, elements belonging to Group 13 of the periodic table, and carrying elements that are metals A metal oxide, an element belonging to Group 2 of the periodic table, and A hydroxide and the periodic table element belonging to Group 13 of the genus and is an element, and composite hydroxide with a hydroxide of an element which is a metal, and the like. Specific examples include magnesium oxide, zirconium oxide, lanthanum oxide, alumina supporting KF, hydrotalcite compounds, and the like, and hydrotalcite compounds are preferable. Hydrotalcite compounds include natural products (Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O) and synthetic products, more preferably (Mg _4.3 Al ₂ (OH) of the synthetic products. _12.6 CO ₃ · mH ₂ O).

The amount of hydrotalcite compound added depends on the amount of residual chlorine used during polyethylene polymerization. For example, when the residual chlorine concentration is 20 ppm by weight, the required amount of hydrotalcite compound is 140 ppm by weight. However, the degree of cleanness, coloration and unreacted chlorine are affected by the amount of hydrotalcite compound, and there is no problem if the moldability is in the range of 5 to 500 ppm by weight. . That is, if the amount of the hydrotalcite compound is 5 ppm by weight or more, no coloration is exhibited, and if it is 500 ppm by weight or less, the cleanness is not affected. The amount of unreacted chlorine is the amount of chlorine that exists in polyethylene unreacted with the hydrotalcite compound and may corrode a molding machine or a mold. By controlling the cleanliness, coloration, and unreacted chlorine content, and considering the required cleanliness, coloration degree, and other conditions, it is possible to determine the optimum conditions for the amount added regardless of the residual chlorine concentration. .
Residual chlorine referred to here is chlorine derived from the Ziegler catalyst. In addition to hydrogen chloride derived from the hydrolysis of the catalyst, there are chloride ions that show acidity by hydrolysis, such as titanium trichloride and titanium tetrachloride.

Inorganic solids having these base points do not generate fine particles and elution components, and on the contrary, sometimes adsorb fine particles and elution components. The above hydrotalcite compounds are extremely preferred inorganic solids because they have the property that carbonate ions at the base point are replaced by chloride ions and strongly adsorb the substituted chloride ions.
In addition, inorganic solids with these base points adsorb chloride ions generated from Ziegler catalysts, so adding them to the polyethylene resin composition for clean container packaging can corrode molding machines, molds, and contents.・ Deterioration can be suppressed. Moreover, generation | occurrence | production of the red discoloration thing generate | occur | produced by reaction with a chloride ion, a catalyst residue, an additive residue, etc. can be suppressed. As a result, the contamination of the resin discoloration is reduced in the molded product obtained by melt molding.
On the other hand, pigments, light-shielding agents, etc. that do not elute or adhere to the contents can be used as long as they do not impair cleanliness.

The addition of the inorganic solid having a base point is a method of mixing the inorganic solid with the powder coming out of the polymerization machine and then extruding with an extruder, a method of adding the inorganic solid after melting the powder, and a solid after pelletizing. A method of mixing and further extruding, a method in which an inorganic solid is separately kneaded with a resin to form a master batch (MB), and then mixing with the powder coming out of the polymerization machine and then extruding with an extruder. A method of adding, a method of mixing the master batch after pelletizing the powder and extruding with an extruder, and a method of mixing the master batch after pelletizing the powder can be selected as appropriate.
The resin composition of the present invention is suitable for applications that require cleanliness because less elution of particles into the contents than in containers and packaging. For example, it is suitable for packaging of high-purity chemical containers, medical containers, food containers, semiconductors, hard disks, etc. in the electronics industry.

  As a molding method when the resin composition of the present invention is molded into a container or the like, a generally known method can be used if measures are taken so that the molded product is not contaminated. As, for example, water-cooled or air-cooled inflation molding, blow molding, extrusion pipe molding, rotational molding, injection molding, fusion molding of injection molded products, injection (biaxial stretching) blow molding, extrusion sheet molding and vacuum molding, etc. A molding method is used. Moreover, it is good also as single layer container packaging and multilayer container packaging using these shaping | molding methods. In the case of multilayer container packaging, the resin composition of the present invention can be suitably used for the innermost layer in contact with the contents, but it may be used for other layers with respect to coloring, corrosion of equipment, and the like. For layers other than the resin composition of the present invention, thermoplastic resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyester, and ethylene-vinyl alcohol copolymer can be used.

Description will be made based on an embodiment of the present invention.
First, the measurement method used in the examples will be described.
1) Density measurement It measured based on JISK7112-1999 (D method). The strand extruded from a standard melt indexer at 190 ° C. was cooled, immersed in a 120 ° C. oil bath for 1 hour in a nitrogen atmosphere, cooled in a thermostatic chamber at 23 ° C. for 1 hour, and then measured with a density gradient tube.
2) Melt flow rate (MFR) measurement Measured according to JIS K7210-1999, condition code D.
3) Cleanness measurement (i) Bottle molding Using a blow molding machine with a 50 mm diameter screw, the resin was extruded at a cylinder temperature of 180 ° C, and a cylindrical container having a capacity of 200 ml was molded at a mold temperature of 20 ° C.
(Ii) Film formation Using a blow molding machine with a 50 mm diameter screw, the resin was extruded at a cylinder temperature of 180 ° C to form a tubular film.
(Iii) Measuring method 100 ml of ultrapure water (purified using Trepure LV-10T (manufactured by Toray Industries, Inc.) (registered trademark)) was put into the molded container and package, and washed with shaking for 15 seconds to be drained. This shaking washing was repeated 5 times. The container / packaging was refilled with 100 ml of ultrapure water and stored as it was at room temperature for 4 weeks. After 4 weeks, 5 ml was collected from this filling water, and the number of fine particles of 0.2 μm or more leached into it was measured with a particle counter (KL-22 (manufactured by Lion Co., Ltd.)). The number of fine particles contained in water can be obtained by the following equation (7), which is defined as the cleanness.

When the degree of cleanness was 500 pieces / ml or less, the judgment was “good”.
4) Color tone observation Resin was extruded on the same conditions as said (3) (i) and (ii), and the resin lump was obtained. The resin lump immediately after solidification was compared with a comparative product, and x was given when redness was felt, and Y was given when the whiteness was equivalent. As a comparative product, a product obtained by extruding commercially available polyethylene resin Suntec-HD B871 (manufactured by Asahi Kasei Chemicals Corporation (registered trademark)) was used.

5) Iron plate corrosion test The iron plate corrosion test is a test to measure the effect of chloride ion adsorption by an inorganic solid having a base point, and in the absence of a neutralizing agent, the metal under high temperature and high humidity by free chloride ions contained in the resin. Corrosion occurs and rust is generated, but the effect can be measured by the fact that rust does not occur when chloride ions are absorbed by the inorganic solid having a base point.
Resin was extruded under the same conditions as in the above bottle molding to obtain a resin mass. The resin was fixed to a degreased iron plate and press-molded. After preheating at 180 ° C. for 5 minutes, it was heated at 9.8 MPa for 25 minutes. Next, after heating for 24 hours at 60 ° C. and 90% RH in a constant temperature and humidity chamber, the appearance of rust on the iron plate was observed. After the test, the iron plate was kept glossy, and the overall rust was rated as x.
6) Measurement of Gel Permeation Chromatography (GPC) Using GPCV2000 type manufactured by Waters, using 1,2,4-trichlorobenzene at 140 ° C. as a solvent, flow rate 1.0 ml / min, sample concentration 20 mg / 15 ml, injection The amount was 413 μl, the sample dissolution temperature was 140 ° C., and the sample dissolution time was 2 hours. The column used was one Shodex UT-807 manufactured by Showa Denko KK and two TSK-GEL GMHHR-H (S) HT manufactured by Tosoh Corporation connected in series from the upstream side.
When the measurement was performed under these conditions, the determination was “good” when the molecular weight of 1000 or less was 0.5 wt% or less.

[Polyethylene polymerization]
Synthesis of titanium catalyst 4 liters of trichlorosilane as a 2 mol / liter heptane solution was charged into a 15 liter reactor sufficiently purged with nitrogen, and kept at 65 ° C. with stirring, and the composition formula AlMg ₆ (C ₂ H ₅ ) ₃ (C ₄ H ₉ ) _6.4 (OC ₄ H ₉ ) 9 liters (6.5 mol in terms of magnesium) of a heptane solution of the organomagnesium component represented by _5.6 was added over 1 hour, and 65 ° C. For 1 hour with stirring. After completion of the reaction, the supernatant was removed and washed 4 times with 7 liters of hexane to obtain a solid material slurry. This solid was separated, dried and analyzed. As a result, it contained 7.42 mmol of magnesium per gram of the solid.
The amount of the slurry containing 500 g of solid was adjusted to 13 liters with hexane, and reacted with 0.93 liter of hexane solution of 1 mol / liter of butanol at 50 ° C. for 1 hour with stirring. After completion of the reaction, the supernatant was removed and washed once with 7 liters of hexane. This slurry was kept at 50 ° C., and 0.84 liter of hexane solution of 1 mol / liter of diethylaluminum chloride was added with stirring and reacted for 1 hour. After completion of the reaction, the supernatant was removed and washed twice with 7 liters of hexane. The slurry was kept at 50 ° C., 60 ml of diethylaluminum chloride 1 mol / liter hexane solution and 60 ml of hexane solution 1 mol / liter titanium tetrachloride were added and reacted for 2 hours. After completion of the reaction, the supernatant was removed and the solid catalyst was isolated and washed with hexane until no free halogen was detected. The solid catalyst had 0.6 wt% titanium.

(2-1) Polymerization of polyethylene resin First, in order to produce a low molecular weight component in the first stage polymerization, a stainless polymerizer 1 having a reaction volume of 300 liters was used, under conditions of a polymerization temperature of 83 ° C and a polymerization pressure of 1 MPa. As the catalyst, the above solid catalyst was introduced at a rate of 4.2 mmol / hr in terms of Ti atom, triethylaluminum was introduced at a rate of 20 mmol / hr in terms of Al atom, and hexane was introduced at a rate of 40 liter / hr. Hydrogen was used as a molecular weight regulator, and polymerization was carried out by supplying the hydrogen so that the gas phase molar concentration (hydrogen / (ethylene + hydrogen)) with respect to the sum of ethylene and hydrogen was 54 mol%. The melt flow rate of the low molecular weight component produced in the polymerization vessel 1 was 40 g / 10 minutes, and the density was 964 kg / m ³ .
The polymer slurry solution in the polymerization vessel 1 is led to a flash drum having a pressure of 0.1 MPa and a temperature of 75 ° C. After separating unreacted ethylene and hydrogen, the pressure is increased by a slurry pump to a stainless polymerizer 2 having a reaction volume of 250 liters. Introduced. In the polymerization vessel 2, triethylaluminum was introduced at a rate of 7.5 mmol / hr and hexane was introduced at a rate of 40 l / hr under the conditions of a temperature of 80 ° C. and a pressure of 0.2 MPa. To this, ethylene, hydrogen, 1-butene, the gas phase molar concentration of hydrogen relative to the sum of ethylene and hydrogen (hydrogen / (ethylene + hydrogen)) is 2.6 mol%, and the sum of ethylene and 1-butene The gas phase molar concentration of 1-butene (1-butene / (ethylene + 1-butene)) was introduced so as to be 1.5 mol%, and the mass of the low molecular weight component produced in the polymerizer 1 and the polymerizer 2 Ratio of mass of high molecular weight component generated in polymerizer 2 to sum of mass of generated high molecular weight component (mass of high molecular weight component generated in polymerizer 2 / (mass of low molecular weight component generated in polymerizer 1+ The high molecular weight component was polymerized so that the mass of the high molecular weight component produced in the polymerization vessel 2 was 0.42, and a polyethylene resin having a melt flow rate of 0.15 g / 10 minutes and a density of 957 kg / m ³ was produced. .

(2-2) Polymerization of polyethylene resin Polymerization was carried out in the same manner as in (2-1) above except that the gas phase molar concentration of hydrogen (hydrogen / (ethylene + hydrogen)) relative to the sum of ethylene and hydrogen was 13 mol%. A polyethylene resin having a melt flow rate of 0.35 g / 10 min and a density of 956 kg / m ³ was produced.

[Example 1]
The density of hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd .: DHT-4A (registered trademark)) in the molded product is 160 in polyethylene having a density of 957 kg / m ³ and MFR of 0.15 g / 10 min polymerized by a Ziegler catalyst. A hydrotalcite masterbatch with the polyethylene as a base resin was blended so as to have a weight ppm, and a container made of the resin was obtained by a blow molding machine.
As a result of the measurement, the pass / fail judgment was ◯ in any of cleanliness, color tone observation, iron plate corrosion test, and GPC measurement.
The measurement results are shown in Table 1.

[Example 2]
A blow molded container was obtained in the same manner as in Example 1 except that the hydrotalcite concentration in the molded product was 480 ppm by weight.
As a result of the measurement, the pass / fail judgment was ◯ in any of cleanliness, color tone observation, iron plate corrosion test, and GPC measurement.
The measurement results are shown in Table 1.

[Example 3]
A blow molded container was obtained in the same manner as in Example 1 except that the density of polyethylene was 956 kg / m ³ , the MFR was 0.35 g / 10 min, and the hydrotalcite concentration in the molded product was 28 ppm by weight. .
As a result of the measurement, the pass / fail judgment was ◯ in any of cleanliness, color tone observation, iron plate corrosion test, and GPC measurement.
The measurement results are shown in Table 1.

[Example 4]
The density of hydrotalcite (manufactured by Kyowa Chemical Industry: DHT-4A (registered trademark)) in the molded product is 5 in polyethylene having a density of 951 kg / m ³ and MFR of 0.20 g / 10 min polymerized by a chromium-based catalyst. A hydrotalcite masterbatch with the polyethylene as a base resin was blended so as to have a weight ppm, and a container made of the resin was obtained by a blow molding machine.
As a result of the measurement, the pass / fail judgment was ◯ in any of cleanliness, color tone observation, iron plate corrosion test, and GPC measurement.
The measurement results are shown in Table 1.

[Example 5]
The density of hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd .: DHT-4A (registered trademark)) in a polyethylene film having a density of 922 kg / m ³ and MFR of 1.5 g / 10 min polymerized by a Ziegler catalyst is 200 ppm by weight. Then, a hydrotalcite masterbatch using the same polyethylene as a base resin was blended, and a container made of the resin was obtained using an inflation molding machine.
As a result of the measurement, the pass / fail judgment was ◯ in any of cleanliness, color tone observation, iron plate corrosion test, and GPC measurement.
The measurement results are shown in Table 1.

[Example 6]
A blow-molded container was obtained in the same manner as in Example 1 except that high-purity magnesium oxide (manufactured by Tateho Chemical Industry: high-purity magnesium oxide RSG (registered trademark)) was used instead of hydrotalcite.
As a result of the measurement, the pass / fail judgment was ◯ in any of cleanliness, color tone observation, iron plate corrosion test, and GPC measurement.
The measurement results are shown in Table 1.

[Example 7]
A blow molded container was obtained in the same manner as in Example 1 except that zirconium oxide (manufactured by Daiichi rare element chemical industry: zirconium oxide RC-100 (registered trademark)) was used instead of hydrotalcite.
As a result of the measurement, the pass / fail judgment was ◯ in any of cleanliness, color tone observation, iron plate corrosion test, and GPC measurement.
The measurement results are shown in Table 1.

[Comparative Example 1]
The density of hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd .: DHT-4A (registered trademark)) in the molded product is 640 in polyethylene having a density of 957 kg / m ³ and MFR of 0.15 g / 10 min polymerized by a Ziegler catalyst. A hydrotalcite masterbatch with the polyethylene as a base resin was blended so as to have a weight ppm, and a container made of the resin was obtained by a blow molding machine.
As a result of the measurement, the degree of cleanliness exceeded 500 / ml. The other color tone observations, iron plate corrosion tests, and GPC measurement pass / fail judgments were “good”.
The measurement results are shown in Table 1.

[Comparative Example 2]
A container made of the resin was obtained by a blow molding machine without adding polyethylene having a density of 957 kg / m ³ and MFR of 0.15 g / 10 min polymerized by a Ziegler catalyst.
As a result of the measurement, the degree of cleanliness and the GPC measurement were “good”. However, the color observation and the iron plate corrosion test were x.
Table 1 shows the measurement results.

[Comparative Example 3]
A bag made of the resin was obtained by an inflation molding machine without adding polyethylene having a density of 922 kg / m ³ and MFR of 1.5 g / 10 min polymerized by a Ziegler catalyst.
As a result of the measurement, the determination was “good” in both GPC measurement and cleanliness. However, the color observation and the iron plate corrosion test were x.
Table 1 shows the measurement results.

  The composition of the present invention is suitable for containers and packaging used for applications that require cleanliness, such as semiconductors, electronic materials, and high-purity chemical containers.

Claims (4)

A polyethylene resin composition used as a material constituting the innermost layer in contact with at least the contents of a clean container package that protects the contents from contamination, wherein the following (A), (B), (C) and (D clean packaging for the polyethylene resin composition which satisfies the requirements).
(A) Density (JIS K7112-1999) is 890 kg / ^{m 3} or more 975 kg / ^{m 3} or less.
(B) The melt flow rate (JIS K7210-1999, code D) is 0.01 g / 10 min or more and 30 g / 10 min or less.
(C) As an additive, it contains only an inorganic solid having a base point substantially, and the amount of the additive is 5 ppm by weight to 500 ppm by weight with respect to 1 kg of polyethylene resin.
(D) A polyethylene resin is obtained using a Ziegler catalyst. A polyethylene resin composition used as a material constituting the innermost layer in contact with at least the contents of a clean container package that protects the contents from contamination, and includes the following (A), (B) , (C) and (D The polyethylene resin composition for lean container packaging characterized by satisfying the requirements of
(A) Density (JIS K7112-1999) is 890 kg / ^{m 3} or more 975 kg / ^{m 3} or less.
(B) The melt flow rate (JIS K7210-1999, code D) is 0.01 g / 10 min or more and 30 g / 10 min or less.
(C) As an additive, it contains only an inorganic solid having a base point substantially, and the amount of the additive is 5 ppm by weight to 500 ppm by weight with respect to 1 kg of polyethylene resin.
(D) A polyethylene resin is obtained using a chromium-based catalyst. The polyethylene resin composition for packaging clean containers according to claim 1 or 2 , wherein the inorganic solid is a hydrotalcite compound. The clean container packaging formed by shape | molding the polyethylene resin composition for clean container packaging in any one of Claims 1-3.