JP5066308B2 - Organoboron-treated fluorinated chromium polymerization catalyst, method for producing ethylene polymer, and ethylene polymer - Google Patents

Description

The present invention relates to an ethylene polymer polymerization catalyst, an ethylene polymer production method, and an ethylene polymer obtained by the production method.
In detail, an organoboron-treated fluorinated chromium polymerization catalyst, which is an improved catalyst for Philips catalyst, a method for producing an ethylene polymer using the polymerization catalyst, and a creep resistance, impact resistance and moldability obtained by the production method. Are related to ethylene polymers and molded products obtained thereby, which are particularly suitable for large blow molded products.

Ethylene-based polymers are basic materials that represent plastic materials in the industrial field and are widely used in many technical fields. Therefore, molecular weight distribution, fluidity, etc. required according to their applications and molding methods are required. Various properties such as properties and mechanical and thermal properties are widespread.
Various polymerization catalysts have been developed and improved in order to produce such ethylene polymers. Among them, Phillips catalysts are used along with Ziegler catalysts and metallocene catalysts, but Phillips catalysts support chromium atoms supported by supporting chromium compounds on an inorganic oxide support and activating them in a non-reducing atmosphere. It is a chromium catalyst in which at least some of the chromium atoms are hexavalent. With a Philips catalyst, an ethylene-based polymer having a relatively broad molecular weight distribution is obtained, and generally moldability such as blow molding is good.

  Therefore, taking advantage of such characteristics of the Philips catalyst, the ethylene-based polymer based on the Philips catalyst is widely used in the blow molding field, particularly for blow molding of large products. Recently, there is a high demand for large blow molded products such as gasoline tanks and large drums as large plastic products in industrial materials, and there is a demand for higher quality in such products.

Creep resistance and impact resistance are important performances for large blow molded products, but when an ethylene polymer having a wide molecular weight distribution obtained by a conventional Philips catalyst is blow molded to large products, etc. The balance between creep resistance and impact resistance is not good. Creep resistance and impact resistance are contradictory physical properties. When creep resistance is improved, impact resistance is decreased. Conversely, when impact resistance is improved, creep resistance is generally decreased. .
However, in blow molding of a large product or the like, a material excellent in both physical properties is demanded, and it cannot be said that the conventional ethylene polymer can meet such a demand. Furthermore, the moldability often conflicts with physical properties such as creep resistance and impact resistance. When the moldability is improved, the physical properties are lowered. Conversely, when the physical properties are improved, the moldability is generally lowered. . There is a demand for materials that are excellent in moldability in addition to these physical properties. However, it cannot be said that conventional ethylene polymers can meet such demands.

In the prior art, a Philips catalyst containing a fine-grained phosphorus-containing chromium catalyst supported on aluminum silicate and improved in creep resistance and ESCR (environmental stress crack resistance), blow molding Phillips catalyst using an aluminum silicate gel carrier containing aluminum oxide concentrated on the surface of the carrier gel particles, resulting in excellent low temperature impact strength that does not swell in the process (Patent Document 2), rigidity and creep resistance An ethylene-based polymerization method (patent document 3) that uses a catalyst in which a chromium compound, an alumoxane, and an organometallic alkoxide are supported on a carrier, and further an organoboron compound activator, suitable for large blow molding, and has excellent resistance to creep and ESCR. Dialkylaluminum functional group-containing alkoxide and tria In the presence of a Philips catalyst that uses kill aluminum (Patent Document 4), an excellent balance between ESCR properties and impact strength, suitable for large blow molding, a chromium compound supported on an inorganic oxide solid and treated with a fluorine-containing base A number of improved methods such as a polymerization method (Patent Document 5) in which ethylene is subjected to two-stage solution polymerization to regulate HLMI and density have been proposed.
However, in any case, even if the creep resistance and impact resistance are individually improved, it has not yet been achieved that these physical properties are sufficiently improved in a well-balanced manner and that the moldability is also improved. Not in.

  On the other hand, from a viewpoint different from the improvement of the Philips catalyst, in order to improve both the creep resistance and the impact resistance, an ethylene-α olefin copolymer film in which the melt flow rate, the density and the heat of crystal fusion are specified (Patent Document) 6) In addition, in order to improve moldability, an ethylene-based resin (Patent Document 7) that specifies an elution component by a cross fractionation method is also disclosed, but both are related to films and pipes and are large-sized. It is not aimed at improving the blow molding of products.

By the way, when reviewing the prior art with respect to the characteristics of the Philips catalyst, when an ethylene polymer is produced using a fluorinated chromium catalyst obtained by adding a fluorine compound to the chromium catalyst and then activating it, ethylene having a narrow molecular weight distribution is obtained. Although it is known that a polymer is obtained, although the impact resistance is improved by the narrow molecular weight distribution, long-term performance such as creep resistance is greatly reduced.
In order to improve the moldability of the ethylene polymer obtained by the chromium catalyst as the Phillips catalyst, it is effective to control the relaxation component for a long time, and the ethylene polymer obtained by the chromium catalyst has 10,000. It is known that there is about one long chain branch per carbon chain. Since this long chain branching structure works as a relaxation component for a long time, it becomes a high elastic body when the molten ethylene polymer is slowly deformed, and there is no long chain branching obtained with Ziegler catalysts or metallocene catalysts. It is said that the draw-down property in blow molding is better than that of a polymer, and the sag of the parison hardly occurs. Uneven thickness at the time of blow molding hardly occurs, and uneven thickness of the molded product can be suppressed.
As a method for evaluating formability in blow molding, elongation viscosity has recently been frequently used, and is described in detail in Non-Patent Document 1, Patent Document 8, and the like. This is a method that utilizes the phenomenon that the elongational viscosity increases rapidly in the large deformation region due to the entanglement of molecular chains when there is a long-term relaxation component that has a long-chain branching structure. Thus, the extensional viscosity increases greatly in the large deformation region, and the moldability is considered to be better as the elongational viscosity increases greatly.
Furthermore, regarding the balance between the formability and the physical properties of creep resistance and impact resistance, the larger the amount of long chain branching, the lower the molecular weight in the same melt flowability (melt flow). Such long-term performance is generally reduced.
From these facts, it is said that the ethylene polymer obtained by the chromium catalyst is inferior in physical properties to those of the Ziegler catalyst or the metallocene catalyst, although it is excellent in moldability.
Therefore, in the Philips catalyst, if an ethylene polymer having excellent physical properties such as creep resistance and moldability is obtained, it becomes a material having a balance between physical properties and moldability exceeding the conventional level. A precise catalyst control method that introduces an appropriate amount of long-chain branches in the appropriate molecular weight region is difficult with current technology, so specific guidelines on how to improve both physical properties and moldability Has not been obtained yet.

JP-A-5-279421 (Abstract) JP-A-5-279420 (Abstract) JP-A-11-228622 (Abstract) Japanese Patent Laid-Open No. 2002-20212 (Abstract) JP 2002-241424 (Abstract and paragraph 0019) JP-A-7-70238 (Summary) JP 2000-17018 (Abstract) JP 2003-221924 (paragraphs 0003, 0021, 0022, 0095) Kiyoto Koyama Journal of Japanese Society of Rheology Vol. 19 174 (1991)

  Based on the current state of technology in the large-scale blow molding for manufacturing large-sized plastic products and the Philips catalyst for polymerizing the ethylene-based polymer used in the molding described above in the background art, the present invention provides blow molding such as large-sized product blow molding. Achieving a method for efficiently producing an ethylene-based polymer that is suitable for molding and produces a high-quality blow-molded product that has a good balance of creep resistance and impact resistance, and that improves moldability. It is an object of the present invention to improve the function of the Phillips catalyst.

  In order to solve the above problems, the present inventors have realized an ethylene-based polymer in which the creep resistance and impact resistance in a blow-molded product are well balanced and excellent in moldability, and Therefore, seeking a new polymerization catalyst by improving the Phillips catalyst, the correlation between creep resistance, impact resistance and moldability, the relationship between these and the molecular weight distribution and melt fluidity, or the function of the Phillips catalyst In addition, the polymerization conditions, the branched structure of the ethylene-based polymer and the elongational viscosity were studied and discussed.

In order to improve the creep resistance of the ethylene polymer obtained by the chromium catalyst, it is known that the molecular weight distribution should be widened. On the other hand, to improve the impact resistance, the molecular weight distribution should be narrowed. This is often a conflicting requirement. However, the component effective for improving creep resistance is only the component on the high molecular weight side in terms of molecular weight distribution, while the component on the low molecular weight side is removed in terms of molecular weight distribution to improve impact resistance. That is. That is, (1) if the high molecular weight component is increased and the low molecular weight component is decreased, both creep resistance and impact resistance can be improved.
As for moldability, the Philips catalyst has a broad molecular weight distribution compared to other catalysts, and therefore generally provides good blow moldability. (2) The long chain branching in the branched structure of the ethylene polymer causes The draw-down property in molding becomes good, and the parison hangs down and uneven thickness at the time of blow molding hardly occurs. However, as the long-chain branching amount increases, the elongational viscosity increases greatly in the large deformation region and the moldability is improved, but the molecular weight of the same melt flowability is lowered, and thus the creep resistance is lowered. Therefore, (3) both physical properties and moldability can be improved if an appropriate amount of long-chain branches having an appropriate length can be introduced into an appropriate molecular weight region.
From the viewpoint of the Phillips catalyst, (4) when an ethylene polymer is produced using a chromium catalyst obtained by fluorinating a Philips catalyst, an ethylene polymer having a narrow molecular weight distribution is obtained, and the molecular weight distribution becomes narrow. Impact resistance is improved, but creep resistance is greatly reduced. (5) And the knowledge from the conventional improvement proposal in a Philips catalyst as described in paragraph 0005 can also be considered.

  Based on the recognition of the above (1) to (5), an ethylene polymer that achieves a good balance of both creep resistance and impact resistance in a blow-molded product and improves moldability is realized. In order to obtain a new polymerization catalyst by improving the above, repeated investigations and considerations described in paragraph 0010, mainly the correlation between creep resistance, impact resistance and moldability, correlation with molecular weight distribution, elongational viscosity, etc. Thus, various attempts were made to improve the constitution and function of the Philips catalyst, and the basic constitution of the present invention could be found.

The present invention basically comprises an improved catalyst of a Philips catalyst, in which a chromium compound is supported on an inorganic oxide support, and activated in a non-reducing atmosphere, so that at least a part of the chromium atoms supported is 6 A novel organoboron-treated fluorinated chromium polymerization catalyst, which was activated after fluorination treatment and supported by contact with a specific organoboron compound, was used as a basic invention in a chromized chromium catalyst, The present invention realizes an ethylene-based polymer in which both creep resistance and impact resistance are well balanced and moldability is improved.
And this invention is a specific ethylene type | system | group obtained from the method of polymerizing ethylene single-piece | unit or ethylene and alpha-olefin, and manufacturing an ethylene type polymer using this organoboron treatment fluorinated chromium polymerization catalyst, and this manufacturing method Polymers and blow-molded products molded from such ethylene-based polymers, particularly large blow-molded products, also belong to the invention group.

In the novel organoboron-treated fluorinated chromium polymerization catalyst of the present invention, the related prior art will be described. US Pat. No. 4,877,763 (2nd column, lines 12 to 30) discloses ethylene using a chromium catalyst. When hydrocarbyl boron monohydrocarbyl oxide (dialkylalkoxyborane), which is a kind of organoboron compound, is added during polymerization, the low molecular weight side of the molecular weight distribution does not spread and the high molecular weight side It is disclosed that only spread. However, according to this disclosure, the creep resistance should be improved, but it actually spreads to the low molecular weight side, and it is not an established technique, and there is no description regarding physical properties and moldability. Further, although there is a description that the chrome catalyst may be fluorinated (6 column 27 to 30), the effect of performing both fluorination and organic boron compound loading has not been found.
WO94 / 13708 discloses a chromium catalyst obtained by bringing diethylethoxyborane or triethylborane, which is a kind of organoboron compound, into contact with an activated chromium catalyst in an inert hydrocarbon solvent, and removing and drying the solvent. (Examples 15 and 16 on pages 12 to 14 and Examples 37 to 40 on pages 22 to 24), there is no detailed examination on the molecular weight distribution and no description on physical properties and moldability, and the chromium catalyst is fluorinated. There is no description, and the effect of performing both fluorination and organoboron compound loading has not been found.
Accordingly, these prior arts do not suggest the present invention having the structure and features described in paragraph 0013.

  In the above, since the technical background and background of the creation of the present invention and the basic configuration and features of the present invention have been described in general, the following invention group will be described clearly here as a whole. The invention of [1] is a basic invention, and the other inventions are inventions that utilize or embody the basic invention. The entire invention group of [1] to [8] is collectively referred to as “the present invention”.

[1] A fluorinated chromium catalyst in which at least a part of chromium atoms is hexavalent by containing a fluorine compound in a chromium catalyst supported on an inorganic compound carrier and activated in a non-reducing atmosphere is represented by the following general formula (1 ), An organoboron-treated fluorinated chromium polymerization catalyst in which the organoboron compound represented by (2) or (3) is brought into contact with the organoboron compound.
R ¹ R ² R ³ B (1)
R ⁴ R ⁵ B (OR ⁶ ) (2)
R ⁷ R ⁸ BOBR ⁹ R ¹⁰ (3)
(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ may be the same or different and each has 1 to 18 carbon atoms. R ¹ , R ² or R ⁴ , R ⁵ may be linked to form a ring.
[2] The organic boron-treated fluorinated chromium polymerization catalyst according to [1], wherein the molar ratio of the organic boron compound to the chromium atom is 0.1 to 10.
[3] A method for producing an ethylene polymer, characterized by polymerizing ethylene alone or copolymerizing ethylene and an α-olefin using the organoboron-treated fluorinated chromium polymerization catalyst in [1] or [2].
[4] Obtained by the method for producing an ethylene polymer in [3], having an HLMFR of 1 to 100 g / 10 min and a density of 0.930 to 0.970 g / cm ³ Polymer.
[5] A large blow obtained by the method for producing an ethylene-based polymer according to [3], having an HLMFR of 1 to 15 g / 10 minutes and a density of 0.940 to 0.960 g / cm ^3. Ethylene polymer for product molding.
[6] A blow molded product molded from the ethylene polymer in [4].
[7] A large blow molded product molded from the ethylene polymer for molding a large blow product in [5].
[8] The large blow molded container according to [7], wherein creep resistance, impact resistance, and moldability are improved.

In the present invention, by using a novel organoboron-treated fluorinated chromium polymerization catalyst to polymerize ethylene alone or ethylene and α-olefin, both creep resistance and impact resistance, which are generally contradictory properties, are balanced. It is possible to produce an ethylene-based polymer that is excellent and has improved moldability.
Such an ethylene polymer is suitable for a blow molded product as an application, and can particularly produce a large, high-quality blow molded container with good moldability.

  The present invention has been described above generally along the basic configuration of the present invention as means for solving the problem, but in the following, embodiments of the present invention group will be described in detail. To do.

1. Organoboron treated fluorinated chromium polymerization catalyst
A chromium catalyst that is supported on an inorganic oxide carrier and is activated in a non-reducing atmosphere and becomes at least part of the chromium atoms becomes hexavalent is generally known as a Philips catalyst.
Matsuura, Kazuo, edited by Naotaka Mikami, "Polyethylene Technology Reader", page 81 2001 P. McDaniel; Advances in Catalysis Vol. 33 p. 47 (1985) Academic Press Inc. , M.M. P. McDaniel “Handbook of Heterogeneous Catalysis” p. 2400 (1997) VCH, M.M. B. Welch et al. “Handbook of Polyolefins Synthesis and Properties” p. 21 (1993) Marcel Dekker et al. Outline this catalyst.

(1) Inorganic compound carrier In the present invention, an inorganic compound carrier, preferably an inorganic oxide carrier, is used as a carrier.
The inorganic oxide is preferably an oxide of a Group 2, 3, 4, 13 or 14 metal of the periodic table (periodic table according to the 1990 rule of the inorganic compound nomenclature), specifically magnesia, titania, Examples include zirconia, alumina, silica, tria, silica-titania, silica-zirconia, silica-alumina, or mixtures thereof. Of these, silica, silica-titania, silica-zirconia, and silica-alumina are preferable. In the case of silica-titania, silica-zirconia, silica-alumina, titanium, zirconium or aluminum atoms as metal components other than silica are 0.2 to 10% by weight, preferably 0.5 to 7% by weight, more preferably 1 to Those containing 5% by weight are used.
The production method, physical properties and characteristics of the carrier suitable for these chromium catalysts are described in C.I. E. Marsden “Preparation of Catalysts” Vol. V p. 215 (1991) Elsevier Science Publishers, C.I. E. Marsden; Plastics, Rubber and Compositions Processing and Applications Vol. 21 p. The outline is described in documents such as 193 (1994).

The surface area, if the carrier used for general chromium catalysts as well as 200~800m ² / g, preferably 300~700m ² / g, more preferably in the range of 400-600m ² / g used . The pore volume is 0.5 to 3.0 cm ³ / g, preferably 0.7 to 2.7 cm ³ / g, more preferably 1.0 to the same as in the case of a carrier used for a general chromium catalyst. The thing of the range of 2.5 cm < ³ > / g is used. The average particle diameter is 10 to 200 [mu] m, preferably 20 to 150 [mu] m, and more preferably 30 to 100 [mu] m, as in the case of a carrier used for a general chromium catalyst.

(2) Chromium compound A chromium compound is supported on the inorganic oxide carrier. As the chromium compound, any compound may be used as long as it is a compound in which at least a part of chromium atoms becomes hexavalent by activating in a non-reducing atmosphere after supporting, including chromium oxide, chromium halide, chromium oxyhalide, Examples thereof include chromate, dichromate, chromium nitrate, chromium carboxylate, chromium sulfate, chromium-1,3-diketo compound, chromate ester and the like.
More specifically, chromium trioxide, chromium trichloride, chromyl chloride, potassium chromate, ammonium chromate, potassium dichromate, chromium nitrate, chromium sulfate, chromium acetate, tris (2-ethylhexanoate) chromium, Examples thereof include chromium acetylacetonate and bis (t-butyl) chromate. Among these, chromium trioxide, chromium acetate, and chromium acetylacetonate are preferable.

  Even when a chromium compound having an organic group such as chromium acetate or chromium acetylacetonate is used, the organic group portion burns by activation in a non-reducing atmosphere described later, and finally chromium trioxide was used. It is known that it reacts with the hydroxyl group on the surface of the inorganic oxide carrier as in the case, and at least a part of the chromium atoms become hexavalent and are fixed in the structure of chromate (VJ Ruddic et al. J. Phys. Chem. 100 p. 11062 (1996), SM Augustin et al .; J. Catal. Vol. 161 p. 641 (1996)).

In order to support the chromium compound on the inorganic oxide carrier, a known method such as a method in which a chromium compound solution is impregnated in a solvent and then the solvent is distilled off or a chromium compound is sublimated without using a solvent. An appropriate method may be used depending on the type of chromium compound to be used. It is also possible to add a chromium compound during the production of the inorganic oxide carrier and use an inorganic oxide carrier containing the chromium compound from the beginning.
The amount of the chromium compound to be supported is 0.2 to 2.0% by weight, preferably 0.3 to 1.7% by weight, more preferably 0.5 to 1.5% by weight with respect to the support as chromium atoms. is there.

(3) Fluorination In the present invention, it is essential that the chromium catalyst supported on the inorganic oxide support further contain a fluorine compound.
The fluorination can be carried out by a known method such as a method in which a fluorine compound solution is impregnated in a solvent and then the solvent is distilled off or a method in which a fluorine compound is sublimated without using a solvent. An appropriate method may be used depending on the type of the above. The inorganic oxide carrier may contain the fluorine compound after the chromium compound is supported, or the chromium compound may be supported after the fluorine compound is contained, but the fluorine compound is contained after the chromium compound is supported. It is preferable to make it.
Content of a fluorine compound is 0.1-10 weight% as content of a fluorine atom, Preferably it is 0.3-8 weight%, More preferably, it is 0.5-5 weight%.

Examples of the fluorine compound include hydrogen fluoride HF, ammonium fluoride NH ₄ F, ammonium silicofluoride (NH ₄ ) ₂ SiF ₆ , ammonium borofluoride NH ₄ BF ₄ , ammonium monohydrogen difluoride (NH ₄ ) HF ₂ , hexa Fluorine-containing salts such as ammonium fluorophosphate NH ₄ PF ₆ and tetrafluoroborate HBF ₄ are used, among which ammonium silicofluoride and ammonium monohydrogen difluoride are preferable.
It is preferable from the viewpoint of uniformity that these are dissolved in an organic solvent such as water or alcohol and then impregnated with the chromium catalyst. However, they may be mixed with the chromium catalyst as a solid. When dissolved and impregnated, it is more preferable to use an organic solvent such as alcohol in order to suppress shrinkage of the pore volume due to surface tension. When a solvent is used, the solvent is removed by a known method such as air drying, vacuum drying or spray drying.

By activation in a non-reducing atmosphere described later, these fluorine compounds are thermally decomposed to fluorinate the inorganic oxide carrier. For example, when silica is used as the inorganic oxide carrier and ammonium silicofluoride is used as the fluorine compound, the ammonium fluorosilicate is thermally decomposed as follows to generate hydrogen fluoride HF and silicon fluoride SiF ₄ ,
(NH ₄ ) ₂ SiF ₆ → 2NH ₃ + 2HF + SiF ₄
Furthermore, it is known that HF and SiF ₄ react with silanol groups on the silica surface to fluorinate (B. Rebentorf; Journal of Molecular Catalysis Vol. 66 p. 59 (1991), A. Noshay et al. “See Transition Metal Catalyzed Polymerizations—Ziegler Natta and Metathesis Polymerizations”, p. 396 (1988) Cambridge University Press).
Si-OH + HF → Si-F + H ₂ O
_{Si-OH + SIF 4 → Si} -O-SiF 3 + HF
2Si—OH + SiF ₄ → (Si—O) ₂ SiF ₂ + 2HF
Therefore, even when a solid of a fluorine compound such as a fluorine-containing salt is mixed with a chromium catalyst, the fluorine compound is eventually thermally decomposed, so that the same reaction occurs and the chromium catalyst is fluorinated. Alternatively, a method of introducing a fluorine compound during the activation process may be used. However, in this case, since the fluorine compound solid is fluidized in the gas, it is preferable to use a fluorine compound solid that is as fine as possible from the viewpoint of uniformity.

(4) Activation Activation is performed after the fluorine catalyst is contained in the chromium catalyst. Activation is performed in a non-reducing atmosphere substantially free of moisture. For example, although it is performed under oxygen or air, an inert gas may coexist. Preferably, it is carried out in a fluidized state using sufficiently dried air through which molecular sieves or the like are circulated.
Activation is performed at a temperature of 400 to 900 ° C, preferably 450 to 850 ° C, more preferably 500 to 800 ° C for 30 minutes to 48 hours, preferably 1 to 24 hours, more preferably 2 to 12 hours. As a result, at least a part of the chromium atom of the chromium compound supported on the inorganic oxide support is oxidized to hexavalent and chemically fixed as a chromate ester on the support as described above. Further, as described above, the carrier is fluorinated.

By the above, a fluorinated chromium catalyst can be obtained, but before loading the chromium compound, after loading the chromium compound, or before activation after containing the fluorine compound or after containing the fluorine compound, titanium alkoxides such as titanium tetraisopropoxide, zirconium Metal alkoxides or organometallic compounds represented by zirconium alkoxides such as tetrabutoxide, aluminum alkoxides such as aluminum tributoxide, organoaluminums such as trialkylaluminum, organomagnesiums such as dialkylmagnesium, etc. A known method for adjusting the ethylene polymerization activity and the molecular weight and molecular weight distribution of the resulting ethylene polymer may be used in combination.
In these metal alkoxides or organometallic compounds, the organic group portion is combusted by activation in a non-reducing atmosphere, and is oxidized into a metal oxide such as titania, zirconia, alumina, or magnesia and contained in the catalyst.
These methods are described in C.I. E. Marsden; Plastics, Rubber and Composites Processing and Applications Vol. 21 p. 193 (1994), T.W. Pullukat et al. J .; Polym. Sci. , Polym. Chem. Ed. Vol. 82 p. 118 (1980), M.M. P. McDaniel et al. J .; Catal. Vol. 82 p. 118 (1983) and the like are outlined or detailed.

(5) Organoboron compound treatment In the present invention, an organoboron treatment in which an activated boron chrome catalyst is brought into contact with an organoboron compound in an inert hydrocarbon solvent, and the solvent is removed and dried to carry the organoboron compound. Produces a fluorinated chromium catalyst.

A) Organoboron compound The organoboron compound is represented by the following general formulas (1) to (3).
R ¹ R ² R ³ B (1)
R ⁴ R ⁵ B (OR ⁶ ) (2)
R ⁷ R ⁸ BOBR ⁹ R ¹⁰ (3)
(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ may be the same or different and each has 1 to 18 carbon atoms. R ¹ , R ² or R ⁴ , R ⁵ may be linked to form a ring.

Specific examples of the organic boron compound R ¹ R ² R ³ B represented by the general formula (1) include trialkylborane, 1-alkylboracyclopentane, 1-alkylboracyclohexane, 9-alkyl-9-borabicyclo [3 , 3,1] nonane, 3-alkyl-3-borabicyclo [3,3,1] nonane, 3-alkyl-3-borabicyclo [4,2,1] nonane, and the like.

  Specific examples of the trialkylborane include trimethylborane, triethylborane, tri-n-propylborane, tri-i-propylborane, tri-n-butylborane, tri-i-butylborane, tri-n-hexylborane, tri-n-octylborane and the like. Can be mentioned.

  Specific examples of 1-alkylboracyclopentane include 1-methylboracyclopentane, 1-ethylboracyclopentane, 1- (n-propyl) boracyclopentane, 1- (i-propyl) boracyclopentane, 1- (N-butyl) boracyclopentane, 1- (i-butyl) boracyclopentane, 1- (t-butyl) boracyclopentane, 1- (n-hexyl) boracyclopentane, 1- (n-octyl) bora And cyclopentane.

  Specific examples of 1-alkylboracyclohexane include 1-methylboracyclohexane, 1-ethylboracyclohexane, 1- (n-propyl) boracyclohexane, 1- (i-propyl) boracyclohexane, 1- (n-butyl) Examples include boracyclohexane, 1- (i-butyl) boracyclohexane, 1- (t-butyl) boracyclohexane, 1- (n-hexyl) boracyclohexane, 1- (n-octyl) boracyclohexane, and the like.

  Specific examples of 9-alkyl-9-borabicyclo [3,3,1] nonane include 9-methyl-9-borabicyclo [3,3,1] nonane, 9-ethyl-9-borabicyclo [3,3,1. ] Nonane, 9- (n-propyl) -9-borabicyclo [3,3,1] nonane, 9- (i-propyl) -9-borabicyclo [3,3,1] nonane, 9- (n-butyl) -9-borabicyclo [3,3,1] nonane, 9- (i-butyl) -9-borabicyclo [3,3,1] nonane, 9- (t-butyl) -9-borabicyclo [3,3,1 Nonane, 9- (n-hexyl) -9-borabicyclo [3,3,1] nonane, 9- (n-octyl) -9-borabicyclo [3,3,1] nonane, and the like.

  Specific examples of 3-alkyl-3-borabicyclo [3,3,1] nonane include 3-methyl-3-borabicyclo [3,3,1] nonane and 3-ethyl-3-borabicyclo [3,3,1. ] Nonane, 3- (n-propyl) -3-borabicyclo [3,3,1] nonane, 3- (i-propyl) -3-borabicyclo [3,3,1] nonane, 3- (n-butyl) -3-borabicyclo [3,3,1] nonane, 3- (i-butyl) -3-borabicyclo [3,3,1] nonane, 3- (t-butyl) -3-borabicyclo [3,3,1 Nonane, 3- (n-hexyl) -3-borabicyclo [3,3,1] nonane, 3- (n-octyl) -3-borabicyclo [3,3,1] nonane, and the like.

  Specific examples of 3-alkyl-3-borabicyclo [4,2,1] nonane include 3-methyl-3-borabicyclo [4,2,1] nonane and 3-ethyl-3-borabicyclo [4,2,1. ] Nonane, 3- (n-propyl) -3-borabicyclo [4,2,1] nonane, 3- (i-propyl) -3-borabicyclo [4,2,1] nonane, 3- (n-butyl) -3-borabicyclo [4,2,1] nonane, 3- (i-butyl) -3-borabicyclo [4,2,1] nonane, 3- (t-butyl) -3-borabicyclo [4,2,1 Nonane, 3- (n-hexyl) -3-borabicyclo [4,2,1] nonane, 3- (n-octyl) -3-borabicyclo [4,2,1] nonane, and the like.

Specific examples of the organic boron compound R ⁴ R ⁵ B (OR ⁶ ) represented by the general formula (2) include dialkylalkoxyborane, 1-alkoxyboracyclopentane, 1-alkoxyboracyclohexane, 9-alkoxy-9-borabicyclo. Examples include [3,3,1] nonane, 3-alkoxy-3-borabicyclo [3,3,1] nonane, 3-alkoxy-3-borabicyclo [4,2,1] nonane.

  Specific examples of the dialkylalkoxyborane include dimethylmethoxyborane, dimethylethoxyborane, dimethyl-n-propoxyborane, dimethyl-i-propoxyborane, dimethyl-n-butoxyborane, dimethyl-i-butoxyborane, and dimethyl-t-butoxy. Borane, diethylmethoxyborane, diethylethoxyborane, diethyl-n-propoxyborane, diethyl-i-propoxyborane, diethyl-n-butoxyborane, diethyl-i-butoxyborane, diethyl-t-butoxyborane, di (n-propyl) ) Methoxyborane, di (n-propyl) ethoxyborane, di (n-propyl) -n-propoxyborane, di (n-propyl) -i-propoxyborane, di (n-propyl) -n-butoxyborane, di (N-propyl) -i-bu Xyborane, di (n-propyl) -t-butoxyborane, di (i-propyl) methoxyborane, di (i-propyl) ethoxyborane, di (i-propyl) -n-propoxyborane, di (i-propyl) -I-propoxyborane, di (i-propyl) -n-butoxyborane, di (i-propyl) -i-butoxyborane, di (i-propyl) -t-butoxyborane, di (n-butyl) methoxyborane , Di (n-butyl) ethoxyborane, di (n-butyl) -n-propoxyborane, di (n-butyl) -i-propoxyborane, di (n-butyl) -n-butoxyborane, di (n- Butyl) -i-butoxyborane, di (n-butyl) -t-butoxyborane, di (i-butyl) methoxyborane, di (i-butyl) ethoxyborane, di (i-butyl)- -Propoxyborane, di (i-butyl) -i-propoxyborane, di (i-butyl) -n-butoxyborane, di (i-butyl) -i-butoxyborane, di (i-butyl) -t-butoxy Borane, di (n-hexyl) methoxyborane, di (n-hexyl) ethoxyborane, di (n-hexyl) -n-propoxyborane, di (n-hexyl) -i-propoxyborane, di (n-hexyl) -N-butoxyborane, di (n-hexyl) -i-butoxyborane, di (n-hexyl) -t-butoxyborane, di (n-octyl) methoxyborane, di (n-octyl) ethoxyborane, di ( n-octyl) -n-propoxyborane, di (n-octyl) -i-propoxyborane, di (n-octyl) -n-butoxyborane, di (n-octyl) -i-but Xiborane, di (n-octyl) -t-butoxyborane and the like can be mentioned.

  Specific examples of 1-alkoxyboracyclopentane include 1-methoxyboracyclopentane, 1-ethoxyboracyclopentane, 1- (n-propoxy) boracyclopentane, 1- (i-propoxy) boracyclopentane, 1- (N-butoxy) boracyclopentane, 1- (i-butoxy) boracyclopentane, 1- (t-butoxy) boracyclopentane, 1- (n-hexyloxy) boracyclopentane, 1- (n-octyloxy) ) Boracyclopentane.

  Specific examples of 1-alkoxyboracyclohexane include 1-methoxyboracyclohexane, 1-ethoxyboracyclohexane, 1- (n-propoxy) boracyclohexane, 1- (i-propoxy) boracyclohexane, 1- (n-butoxy). Examples include boracyclohexane, 1- (i-butoxy) boracyclohexane, 1- (t-butoxy) boracyclohexane, 1- (n-hexyloxy) boracyclohexane, 1- (n-octyloxy) boracyclohexane, and the like.

  Specific examples of 9-alkoxy-9-borabicyclo [3,3,1] nonane include 9-methoxy-9-borabicyclo [3,3,1] nonane and 9-ethoxy-9-borabicyclo [3,3,1. ] Nonane, 9- (n-propoxy) -9-borabicyclo [3,3,1] nonane, 9- (i-propoxy) -9-borabicyclo [3,3,1] nonane, 9- (n-butoxy) -9-borabicyclo [3,3,1] nonane, 9- (i-butoxy) -9-borabicyclo [3,3,1] nonane, 9- (t-butoxy) -9-borabicyclo [3,3,1 Nonane, 9- (n-hexyloxy) -9-borabicyclo [3,3,1] nonane, 9- (n-octyloxy) -9-borabicyclo [3,3,1] nonane, and the like.

  Specific examples of 3-alkoxy-3-borabicyclo [3,3,1] nonane include 3-methoxy-3-borabicyclo [3,3,1] nonane and 3-ethoxy-3-borabicyclo [3,3,1. ] Nonane, 3- (n-propoxy) -3-borabicyclo [3,3,1] nonane, 3- (i-propoxy) -3-borabicyclo [3,3,1] nonane, 3- (n-butoxy) -3-borabicyclo [3,3,1] nonane, 3- (i-butoxy) -3-borabicyclo [3,3,1] nonane, 3- (t-butoxy) -3-borabicyclo [3,3,1 Nonane, 3- (n-hexyloxy) -3-borabicyclo [3,3,1] nonane, 3- (n-octyloxy) -3-borabicyclo [3,3,1] nonane, and the like.

Specific examples of 3-alkoxy-3-borabicyclo [4,2,1] nonane include
3-methoxy-3-borabicyclo [4,2,1] nonane, 3-ethoxy-3-borabicyclo [4,2,1] nonane, 3- (n-propoxy) -3-borabicyclo [4,2,1] Nonane, 3- (i-propoxy) -3-borabicyclo [4,2,1] nonane, 3- (n-butoxy) -3-borabicyclo [4,2,1] nonane,
3- (i-butoxy) -3-borabicyclo [4,2,1] nonane, 3- (t-butoxy) -3-borabicyclo [4,2,1] nonane, 3- (n-hexyloxy) -3 -Borabicyclo [4,2,1] nonane, 3- (n-octyloxy) -3-borabicyclo [4,2,1] nonane and the like.

The organoboron compound R ⁷ R ⁸ BOBR ⁹ R ¹⁰ represented by the general formula (3) is bis (dialkylboron) oxide. Specific examples thereof include bis (dimethylboron) oxide, bis (diethylboron) oxide, Bis (di-n-propylboron) oxide, bis (dii-propylboron) oxide, bis (din-butylboron) oxide, bis (dii-butylboron) oxide, bis (din-hexylboron) oxide, bis ( Di-n-octylboron) oxide and the like.

  Among these organoboron compounds, trialkylborane, dialkylalkoxyborane, and 9-alkyl-9-borabicyclo [3,3,1] nonane are preferable, and trialkylborane is particularly preferable. Specifically, trimethylborane, triethylborane, tri-n-butylborane, diethylmethoxyborane, diethylethoxyborane, 9-methyl-9-bicyclo [3,3,1] nonane, 9-methoxy-9-bicyclo [3,3 , 1] nonane, particularly trimethylborane, triethylborane and tri-n-butylborane are preferred, and triethylborane is particularly preferred.

B) Method for synthesizing organoboron compounds The method for synthesizing organoboron compounds represented by the general formulas (1) to (3) is well known. Wilkinson, “Comprehensive Organic Chemistry” Vol. 1 Chapters 51 and 52 (1982) Pergamon Press.
Among the organoboron compounds R ¹ R ² R ³ B represented by the general formula (1), a method for synthesizing a trialkylborane is obtained by a transmetalation reaction such as the following formulas (i) to (iii), It is synthesized by reacting boron halide with an alkyl metal such as an alkyl lithium compound, an alkyl magnesium compound, or an alkyl aluminum compound.
Transmetallation (X = halogen; M = Li, Mg, Al, etc.)
BX ₃ + MR → RBX ₂ + MX (i)
RBX ₂ + MR → R ₂ BX + MX (ii)
R ₂ BX + MR → R ₃ B + MX (iii)
(i)-(iii) If it shows collectively, it will become like (iv).
BX ₃ + 3MR → R ₃ B + 3MX (iv)

Alternatively, there is a method of transmetallation with trialkoxyboron and an alkyl metal.
B (OR) ₃ + MR → RB (OR) ₂ + MOR (v)
RB (OR) ₂ + MR → R ₂ B (OR) + MOR (vi)
R ₂ B (OR) + MR → R ₃ B + MOR (vii)
(v)-(vii) If it shows collectively, it will become like (viii).
B (OR) ₃ + 3MR → R ₃ B + 3MOR (viii)

Among the organoboron compounds R ⁴ R ⁵ B (OR ⁶ ) represented by the general formula (2), the synthesis method of dialkylalkoxyborane is based on the reaction of alkyldialkoxyborane and alkyl metal as shown in (vi) above. can get.

As another method for synthesizing trialkylborane, there is a method using hydroboration as follows.
BH ₃ + alkene → R ₃ B (ix)
Among the organoboron compounds R ¹ R ² R ³ B represented by the general formula (1), regarding 1-alkylboracyclopentane and 1-alkylboracyclohexane, as shown in the formulas (x) to (xiii), Synthesized using transmetallation or hydroboration.

  Among the organoboron compounds represented by the general formula (2), 1-alkoxyboracyclopentane and 1-alkoxyboracyclohexane were obtained by hydroboration as shown in the formulas (xiv) to (xv). It is synthesized by reacting boracyclopentane or boracyclohexane with alcohol.

Among the organoboron compounds R ¹ R ² R ³ B represented by the general formula (1), alkylborabicyclo [3,3,1] nonane, alkylborabicyclo [4,2,1] nonane and alkoxyborabicyclo [3 , 3,1] nonane and alkoxyborabicyclo [4,2,1] nonane are borabicyclo [3,3,1] nonane and borabicyclo [4,2,1] obtained by reacting cyclooctadiene with borane. Hydroboration of nonane with alkene allows alkylborabicyclo [3,3,1] nonane and alkylborabicyclo [4,2,1] nonane to react with alcohol, and alkoxyborabicyclo [3,3,1 Nonane and alkoxyborabicyclo [4,2,1] nonane can be synthesized.
Even if alkoxyborabicyclo [3,3,1] nonane or alkoxyborabicyclo [4,2,1] nonane is reacted with an alkyl metal, alkylborabicyclo [3,3,1] nonane, alkylborabicyclo [4, 2,1] nonane is obtained. The cases of 1,5-cyclooctadiene and borane are shown in formulas (xvi) and (xvii).

The synthesis method of bis (dialkylboron) oxide R ⁷ R ⁸ BOBR ⁹ R ^{10 represented by} the general formula (3) is obtained by hydrolyzing a trialkylborane as represented by the formula (xviii).
2R ₃ B + H ₂ O → R ₂ B—O—BR ₂ + 2R—H (xviii)

C) Treatment with organoboron compound The amount of the organoboron compound to be treated is such that the molar ratio of the organoboron compound to chromium atoms is 0.1 to 10, preferably 0.5 to 7, and more preferably 1 to 5. It is an amount. When the molar ratio is less than 0.1, the effect of supporting the organoboron compound does not appear, and the creep resistance and impact resistance are the same as when the organoboron compound is not supported. If the molar ratio exceeds 10, the ethylene polymerization activity will be significantly lower than when no organoboron compound is supported. In addition, the increase in the low molecular weight component broadens the molecular weight distribution and improves the creep resistance but lowers the impact resistance. The reason for this decrease in activity is unknown, but it is presumed that the excess organoboron compound binds to the active site chromium and inhibits the ethylene polymerization reaction.

As a method of the treatment reaction with the organic boron compound, the activated fluorinated chromium catalyst and propane, n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, decane, cyclohexane, benzene, toluene, xylene, etc. It is preferable to mix an inert hydrocarbon solvent into a slurry state and add an organoboron compound thereto. The organoboron compound may not be diluted with a solvent or may be diluted with the above inert hydrocarbon solvent.
Although any amount of the solvent per 1 g of the chromium catalyst after activation can be used, it is preferable for the production of the catalyst that the amount can be stirred at least in a slurry state. The treatment reaction temperature is 0 to 150 ° C., preferably 10 to 100 ° C., more preferably 20 to 80 ° C., the treatment reaction time is 5 minutes to 8 hours, preferably 30 minutes to 6 hours, more preferably 1 to 4 hours. is there.
After the treatment reaction, the solvent is removed by removal under reduced pressure or separated by filtration, and the organoboron-treated chromium fluoride catalyst is separated from the solvent as a free-flowing powder.

In using an organoboron compound, a pre-reactor is provided outside the polymerization reactor in the presence or absence of ethylene as a so-called co-catalyst, or pre-contacted with a fluorinated chromium catalyst in a pipe before being introduced into the polymerization reactor. When using the feed method or the method of feeding to the polymerization reactor separately from the fluorinated chromium catalyst and bringing it into contact with the fluorinated chromium catalyst, the molecular weight distribution is broadened due to the increase in low molecular weight components, and the impact resistance is reduced. Resulting in. Moreover, if it is stored for a long time without being separated from the solvent, the ethylene polymerization activity is greatly reduced due to deterioration over time.
The reason for these is unknown, but as far as deterioration with time is concerned, it is assumed that the reaction between the active site chromium and the organoboron compound continues to progress in the solvent, and the structure changes to inhibit the ethylene polymerization reaction. Yes. Therefore, it is necessary to separate the solvent as soon as the treatment reaction is completed. The time required for separating and drying the solvent is preferably within 3 times, preferably within 2 times, more preferably within 1 time after the treatment reaction. The total time from the start of treatment to the completion of solvent removal / drying is 5 minutes to 24 hours, preferably 30 minutes to 18 hours, and more preferably 1 to 12 hours.

After completion of drying, the organoboron-treated fluorinated chromium catalyst is preferably free-flowing. That is, the residual weight of the solvent is 1/10 or less, preferably 1/30, more preferably 1/100 or less of the weight obtained by multiplying the pore volume of the organoboron-treated fluorinated chromium catalyst by the density of the solvent. It is preferable. Here, the pore volume is determined by the BET method by nitrogen adsorption, and the residual weight of the solvent is determined by the following equation.
Residual weight of solvent = (weight of fluorinated chromium catalyst treated with organoboron after drying) − {(weight of organoboron compound) + (weight of fluorinated chromium catalyst)}

2. Production of ethylene polymer (1) Polymerization method In order to produce the ethylene polymer of the present invention using the organoboron-treated fluorinated chromium catalyst described in detail above, a liquid such as slurry polymerization or solution polymerization is used. It can be carried out by a phase polymerization method or a gas phase polymerization method.
The liquid phase polymerization method is usually carried out in a hydrocarbon solvent. Examples of the hydrocarbon solvent include propane, n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, decane, cyclohexane, and benzene. Inert hydrocarbons such as toluene and xylene are used alone or as a mixture.
In the gas phase polymerization method, a commonly known polymerization method such as a fluidized bed or a stirring bed can be adopted in the presence of an inert gas, and in some cases, a so-called condensing mode in which a medium for removing the heat of polymerization coexists can be adopted. it can.

As a polymerization method, not only single-stage polymerization in which an ethylene polymer is produced using one reactor, but also multistage polymerization can be performed by connecting at least two reactors. In the case of multi-stage polymerization, two-stage polymerization is preferred in which two reactors are connected and the reaction mixture obtained by polymerization in the first-stage reactor is continuously fed to the second-stage reactor. Transfer from the first-stage reactor to the second-stage reactor is performed through a connecting pipe, and is performed by a differential pressure due to continuous discharge of the polymerization reaction mixture from the second-stage reactor.
The obtained ethylene polymer is then preferably kneaded. It can be carried out using a single or twin screw extruder or a continuous kneader. Subsequently, the obtained ethylene polymer can be blow-molded by a conventional method.

(2) Polymerization conditions The polymerization temperature in the liquid phase or gas phase polymerization method is generally 0 to 300 ° C, practically 20 to 200 ° C, preferably 50 to 180 ° C, more preferably 70 to 150. ° C.
The catalyst concentration and the ethylene concentration in the reactor may be any concentration as long as the concentration is sufficient for the polymerization to proceed. For example, the catalyst concentration can range from about 0.0001 to about 5% by weight based on the weight of the reactor contents in the case of liquid phase polymerization. Similarly, in the case of gas phase polymerization, the ethylene concentration can be in the range of 0.1 to 10 MPa as the total pressure.
Further, if necessary, hydrogen can be introduced into the polymerization reactor to adjust the molecular weight.

(3) Copolymerization In the method for producing an ethylene polymer of the present invention, in addition to ethylene homopolymerization, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, if necessary, An α-olefin such as 1-octene may be introduced alone or in two or more kinds into a polymerization reactor for copolymerization.
The α-olefin content in the obtained ethylene polymer is 15 mol% or less, preferably 10 mol% or less.

3. Ethylene polymer (1) HLMFR and density According to the method of the present invention, HLMFR (high load melt flow rate) is 0.1 to 1,000 g / 10 min, preferably 0.5 to 500 g / 10 min, and density is 0. An ethylene-based polymer of 900 to 0.980 g / cm ³ , preferably 0.920 to 0.970 g / cm ³ is obtained.
The obtained ethylene-based polymer is excellent in both creep resistance and impact resistance, and is excellent in moldability, and thus exhibits a great effect in blow molded products, particularly large blow molded products. The HLMFR of the ethylene polymer for blow molded products is 1 to 100 g / 10 min, and particularly the ethylene polymer for large blow molded products is 1 to 15 g / 10 min. The density of the ethylene polymer for blow molded products is 0.930 to 0.970 g / cm ³ , and the density of the ethylene polymer for large blow molded products is 0.940 to 0.960 g / cm ³ .

(2) Impact strength and creep resistance Although it may vary depending on HLMFR and density, an ethylene polymer suitable for blow-molded products obtained by the method of the present invention has the Charpy impact strength required by the measurement method described later. The main characteristics of the creep resistance are that Charpy impact strength (−40 ° C.) is 8.0 kJ / m ² or more and creep resistance (breaking time at 6 MPa) is 50 h or more. It is.
The Charpy impact strength is expressed by absorbed energy when the center of the test piece is hit with a hammer and the test piece breaks.
Creep resistance relates to viscoelastic deformation under stress, and represents the time for bending deformation with external force applied.
Both performances represent important qualities in large blow molded products such as gasoline tanks and drum containers.

In the following, the present invention will be described in more detail by giving examples and comparative examples, and the superiority of the present invention and the significance in the configuration of the present invention will be demonstrated.
The measurement methods used in Examples and Comparative Examples are as follows.

a) Polymer treatment for measuring physical properties:
Using a plastograph manufactured by Toyo Seiki Seisakusho Co., Ltd. (labo plast mill ME25; roller shape is R608 type), 0.2% by weight of Ciba Geigy's Irganox B225 is added as an additive, and the number of revolutions per minute in a nitrogen atmosphere It knead | mixed for 7 minutes at 180 degreeC by 40 rotations.

b) High load melt flow rate (HLMFR)
According to JIS K-7210 (2004 edition), Annex A, Table 1-Condition G, the measured value at a test temperature of 190 ° C. and a nominal load of 21.60 kg was shown as HLMFR.

c) Density The density was measured according to JIS K-7112 (2004 edition).

d) Molecular weight distribution Mw / Mn
The generated ethylene polymer was subjected to gel permeation chromatography (GPC) under the following conditions to determine the number average molecular weight (Mn) and the weight average molecular weight (Mw).
[Gel permeation chromatograph measurement conditions]
Apparatus: WATERS 150C model Column: Shodex-HT806M
Solvent: 1,2,4-trichlorobenzene Temperature: 135 ° C
Universal rating using monodisperse polystyrene fractions For the molecular weight distribution indicated by the ratio of Mw to Mn (Mw / Mn) (the larger the Mw / Mn, the wider the molecular weight distribution), "size exclusion chromatography (high-performance liquid polymer) Chromatography) ”by Sadao Mori Kyoritsu Shuppan The data of fractional linear polyethylene with n-alkane and Mw / Mn ≦ 1.2 was applied to the formula of molecular weight and detector sensitivity described on page 96, and The sensitivity of the indicated molecular weight M was determined, and the measured sample value was corrected.
Sensitivity of molecular weight M = a + B / M
(A and b are constants, a = 1.32, b = 189.2)

e) Charpy impact strength A test piece of type 1 was prepared according to JIS K-7111 (2004 edition), the edge direction was edgewise and the notch type was type A (0.25 mm) in dry ice / alcohol- Measured at 40 ° C.

f) Creep resistance JIS K-6774 (2004 version) Annex 5 (normative) shown in Fig. 1 after compression molding a 5.9 mm thick sheet in accordance with JIS K-6922-2 (2004 version) A test piece having the shape and size of the section “Nominal 50” was prepared, and an all-around notch tensile creep test (FNCT) was performed in pure water at 80 ° C. Tensile loads were 88N, 98N, and 108N, and the number of test points was 2 for each load. From the obtained 6-point plot of rupture time and nominal stress in the logarithmic scale, the rupture time at a nominal stress of 6 Ma was used as an index of creep resistance by the least square method.

g) Elongation viscosity strain hardening parameter λmax
Using a capillary rheometer manufactured by Intesco and using a capillary of 3 mmφ × 15 mmL at a temperature of 190 ° C., a test piece was prepared at a piston speed of 20 mm / min.
Using a melten rheometer manufactured by Toyo Seiki Seisakusho, the preheating time was 15 min, the elongational viscosity was measured at a temperature of 170 ° C. and a strain rate of 0.1 / s. The viscosity growth curve obtained in the logarithmic graph of time t and elongational viscosity η has a linear part and a non-linear part when strain hardening (strain hardening) occurs. The ratio between the maximum elongation viscosity ηE, max of the nonlinear part and the estimated viscosity ηL, max in the linear part at the time when ηE, max is given is λmax, which is an index representing the magnitude of nonlinearity in the elongational viscosity.
λmax = ηE, max / ηL, max
In addition, in FIG. 1, the measuring method of this parameter | index was shown typically.

[Example 1]
(1) Preparation of organoboron-treated fluorinated chromium catalyst R. Grace HA30W catalyst (chromium atom loading 1.0% by weight, surface area 500 m ² / g, pore volume 1.5 cm ³ / g) was added 40 g, and methanol 140 ml was added. A solution prepared by dissolving 0.8 g of ammonium monohydrogen difluoride (NH ₄ ) HF ₂ manufactured by Aldrich in 120 ml of methanol was added to a beaker containing the catalyst, and stirred at room temperature for 10 minutes. Methanol was air-dried and further dried with a constant temperature dryer at 110 ° C. to obtain a smooth powder. The amount of fluorine added is 1.3% by weight.
15 g of the obtained powder is put in a quartz glass tube with a 3 cm tube diameter with a perforated plate, set in a cylindrical utilization electric furnace, and fluidized with dry air through molecular sieves at a flow rate of 1.0 L / min. And activated at 600 ° C. for 6 hours. An orange fluorinated chromium catalyst was obtained indicating that it contained hexavalent chromium atoms.
Into a 100 ml flask previously purged with nitrogen, 2 g of the above fluorinated chromium catalyst was placed, and 30 ml of distilled and purified hexane was added to form a slurry. 1.5 ml (B / CR molar ratio = 2) of a 0.5 mol / L-hexane solution of triethylborane manufactured by Tosoh Finechem Co. was added and stirred at 40 ° C. for 2 hours. After completion of the stirring, the solvent was removed under reduced pressure to obtain a free-flowing organoboron-treated fluorinated chromium catalyst. This catalyst showed a brown color after reduction of hexavalent chromium.

(2) Polymerization 100 mg of the organoboron-treated fluorinated chromium catalyst obtained in (1) above and 700 ml of isobutane were charged into a 1.5 L autoclave sufficiently purged with nitrogen, and the internal temperature was raised to 103 ° C. Polymerization was carried out at 103 ° C. while 5 g of 1-hexene was introduced under pressure with ethylene and the ethylene partial pressure was kept at 1.0 MPa. Polymerization was carried out until the productivity (polymer yield per gram of catalyst) reached 3,000 g, and then the content gas was discharged out of the system to terminate the polymerization.
As a result, 140 g of polyethylene was obtained. The polymerization activity per hour with 1 g of catalyst was 1,400 g / g · h. Table 1 shows the measurement results of physical properties (HLMFR, density), molecular weight (Mn, Mw), and molecular weight distribution (Mw / Mn).

[Comparative Example 1]
In Example 1 (1), the HA30W catalyst was similarly activated at 600 ° C. without fluorination. No organic boron treatment was performed. Polymerization was performed in the same manner as in Example 1 (2) using this activated chromium catalyst instead of the organoboron-treated fluorinated chromium catalyst. The polymerization results and physical property measurement results are shown in Table 1. Moreover, GPC compared with the polymer obtained in Example 1 (2) is shown in FIG. The GPC shape and Mn on the low molecular weight side are almost the same, but the polymer obtained in Example 1 (2) shows only the high molecular weight component is increased.

[Comparative Example 2]
In Example 1 (2), polymerization was performed in the same manner as in Example 1 (2), using a fluorinated chromium catalyst before the organic boron treatment instead of the organic boron-treated chromium fluoride catalyst. The polymerization results and physical property measurement results are shown in Table 1. Moreover, GPC compared with the polymer obtained in Example 1 is shown in FIG. It can be seen that the polymer obtained in Comparative Example 2 has a low molecular weight component and a small molecular weight distribution (Mw / Mn).

[Comparative Example 3]
Using the HA30W catalyst activated without fluorination obtained in Comparative Example 1, the organoboron treatment was performed in the same manner as in Example 1 (1) to obtain an organoboron-treated chromium catalyst. Polymerization was conducted in the same manner as in Example 1 (2) using this organoboron-treated chromium catalyst instead of the organoboron-treated chromium fluoride catalyst. The polymerization results and physical property measurement results are shown in Table 1. Moreover, GPC compared with the polymer obtained in Example 1 is shown in FIG. It can be seen that the polymer obtained in Comparative Example 3 is biased toward the low molecular weight side.
As described above, in Example 1, when the organic boron-treated fluorinated chromium catalyst is used, the low molecular weight component does not decrease excessively as in the case of the catalyst in which the chromium catalyst is only fluorinated (Comparative Example 2). In the case of the catalyst treated only with boron (Comparative Example 3), the low molecular weight component does not increase excessively, and a polymer having a high molecular weight component kept moderate and balanced with the low molecular weight component can be obtained. it can. Therefore, it can be said that creep resistance and impact resistance are well balanced.

[Example 2]
W. R. Grace fluorinated chromium catalyst (chromium atom loading 1.0 wt%, surface area 500 m ² / g, pore volume 1.3 cm ³ / g, fluorine content 0.9 wt%) was prepared in Example 1 (1 ) And activated at 700 ° C. Next, an organic boron treatment was performed in the same manner as in Example 1 (1) to obtain an organic boron-treated fluorinated chromium catalyst. Using this catalyst, polymerization was carried out in the same manner as in Example 1 (2) to obtain a polymer having HLMFR and density equivalent to a large blow product. The polymerization results and physical property measurement results are shown in Table 1. It was an ethylene polymer having high impact resistance, high creep resistance, and good moldability index.

[Comparative Example 4]
Polymerization was carried out in the same manner as in Example 1 (2) using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and without treating with organic boron. A polymer having HLMFR and density equivalent to a large blow product was obtained. The polymerization results and physical property measurement results are shown in Table 1.
As in Example 2, the impact resistance was high and the moldability index was good, but the creep resistance was greatly inferior.

[Comparative Example 5]
In Example 1 (1), polymerization was performed in the same manner as in Example 1 (2) using a catalyst that was similarly activated at 600 ° C. without fluorinating the HA30W catalyst, and without performing organic boron treatment. However, the polymerization temperature was 101 ° C., the ethylene partial pressure was 1.4 MPa, and the 1-hexene amount was 5.5 g. A polymer having HLMFR and density equivalent to a large blow product was obtained. The polymerization results and physical property measurement results are shown in Table 1. As in Example 2, the impact resistance was high, but the creep resistance was slightly inferior, and the moldability index was greatly reduced.

[Example 3]
Using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and using tri-n-butylborane manufactured by Aldrich instead of triethylborane manufactured by Tosoh Finechem Co., as in Example 1 (1), an organic boron treatment To obtain an organoboron-treated fluorinated chromium catalyst. Using this catalyst, polymerization was carried out in the same manner as in Example 1 (2) to obtain a polymer having HLMFR and density equivalent to a large blow product. The polymerization results and physical property measurement results are shown in Table 1. It was an ethylene polymer having high impact resistance, high creep resistance, and a good formability index.

[Example 4]
Using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and using triethylborane manufactured by Aldrich instead of triethylborane manufactured by Tosoh Finechem, organic boron treatment was performed in the same manner as in Example 1 (1). And an organic boron-treated fluorinated chromium catalyst was obtained. Using this catalyst, polymerization was carried out in the same manner as in Example 1 (2) to obtain a polymer having HLMFR and density equivalent to a large blow product. The polymerization results and physical property measurement results are shown in Table 1. It was an ethylene polymer having high impact resistance, high creep resistance, and a good formability index.

[Comparative Example 6]
Using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and using triethylaluminum manufactured by Tosoh Finechem Co. instead of triethylborane manufactured by Tosoh Finechem Co., instead of the organic boron treatment of Example 1 (1), organic Aluminum treatment was performed to obtain an organoaluminum-treated fluorinated chromium catalyst instead of the organoboron-treated fluorinated chromium catalyst. Using this catalyst, polymerization was carried out in the same manner as in Example 1 (2). The polymerization results and physical property measurement results are shown in Table 1. Compared with Example 2 using triethylborane, the density was significantly reduced. As a result of measuring ¹³ C-NMR of polyethylene, ethyl branch and n-hexyl branch were observed in addition to n-butyl branch derived from 1-hexene, and it was found that α-olefins were by-produced and copolymerized. It was. Compared to the case of using organic boron, it was difficult to control the density and primary structure due to the by-production of α-olefins.

[Comparative Example 7]
Using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and using tri-n-butylaluminum manufactured by Tosoh Finechem Co. instead of triethylborane manufactured by Tosoh Finechem Co., the organic boron treatment of Example 1 (1) Instead, an organoaluminum treatment was performed to obtain an organoaluminum-treated fluorinated chromium catalyst instead of the organoboron-treated fluorinated chromium catalyst. Using this catalyst, polymerization was carried out in the same manner as in Example 1 (2). The polymerization results and physical property measurement results are shown in Table 1. Compared to the case of Example 3 using tri-n-butylborane, the density was greatly reduced. As a result of measuring ¹³ C-NMR of polyethylene, ethyl branch and n-hexyl branch were observed in addition to n-butyl branch derived from 1-hexene, and it was found that α-olefins were by-produced and copolymerized. It was. Compared to the case of using organic boron, it was difficult to control the density and primary structure due to the by-production of α-olefins.

[Comparative Example 8]
Using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and using diethylaluminum ethoxide manufactured by Tosoh Finechem Co. instead of triethylborane manufactured by Tosoh Finechem Co., instead of the organoboron treatment of Example 1 (1) Then, an organoaluminum treatment was performed to obtain an organoaluminum-treated fluorinated chromium catalyst in place of the organoboron-treated fluorinated chromium catalyst. Using this catalyst, polymerization was carried out in the same manner as in Example 1 (2). The polymerization results and physical property measurement results are shown in Table 1. Although the density reduction due to α-olefin by-product as in Comparative Examples 6 and 7 does not occur, Mn is lower than that in Example 4 using diethylmethoxyborane, and the molecular weight distribution is greatly expanded. .

[Comparative Example 9]
Polymerization was performed in the same manner as in Example 1 (2) using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and without treating with organic boron. However, 3.8 ml (B / CR molar ratio = 2) of a 0.01 mol / L-hexane solution of triethylborane manufactured by Tosoh Finechem Co., Ltd. was mixed with 5 g of 1-hexene and introduced under pressure with ethylene. That is, the organoboron compound was added during the polymerization. Compared to the case of Example 2 where the organoboron treatment was performed, Mn was decreased and the molecular weight distribution was greatly expanded.

[Comparative Example 10]
Polymerization was performed in the same manner as in Example 1 (2) using the fluorinated chromium catalyst activated in 700 ° C. obtained in Example 2 and without treating with organic boron. However, 3.8 ml (B / CR molar ratio = 2) of a 0.01 mol / mol-hexane solution of diethylmethoxyborane manufactured by Aldrich was mixed with 5 g of 1-hexene and introduced under pressure with ethylene. That is, the organoboron compound was added during the polymerization. Compared with the case of Example 4 which performed the organoboron process, Mn has fallen and molecular weight distribution expanded widely.

  The organoboron-treated fluorinated chromium polymerization catalyst of the present invention is characterized by the combined use of fluorination treatment and organoboron treatment, so that both impact resistance and creep resistance are excellent in a well-balanced formability. In order to easily and clearly show the relationship between the configuration and the effect from the results of the comparative example, a simple comparison table is presented as Table 2. (In the table, ○ is used,-is not used)

[Consideration by contrast between Example and Comparative Example]
Since the catalyst and the polymer in Examples 1 to 4 satisfy the requirements of the constitution of the present invention, in Example 1, the molecular weight distribution spreads to the high molecular weight side from the results of FIGS. 4, it is clear from the description in Table 1 that both the impact resistance and the creep resistance are excellent, and the moldability is improved from the λmax value.
In Comparative Examples 1 to 10, from the description of the results in each Comparative Example and the simple description in Table 2, either or all of impact resistance, creep resistance and moldability are inferior compared to each Example, It is clear that these properties are not balanced. In addition, even if an organoaluminum treatment is performed instead of an organoboronation treatment or an organoboron compound is added without polymerization, an effect as in the present invention cannot be obtained.

It is explanatory drawing of the measuring method of the strain hardening parameter (lambda) max of an extensional viscosity. It is GPC which compared the polyethylene of Example 1 (solid line) and the polyethylene of Comparative Example 1 (dotted line). It is GPC which compared the polyethylene of Example 1 (solid line) and the polyethylene of Comparative Example 2 (dotted line). It is GPC which compared the polyethylene of Example 3 (solid line) and the polyethylene of Comparative Example 3 (dotted line). It is a flowchart figure of the catalyst preparation for ethylene polymer manufacture used by this invention.

Claims (7)

The chromium catalyst supported on the inorganic compound carrier contains a fluorine compound in an amount of 0.1 to 10% by weight as a fluorine atom, and is activated in a non-reducing atmosphere to make at least some of the chromium atoms hexavalent. An organic boron compound represented by the following general formula (1), (2) or (3) is brought into contact with a fluorinated chromium catalyst to support the organic boron compound, and the molar ratio of the organic boron compound to the chromium atom is 0.00. 1 to 10 is an organic boron-treated fluorinated chromium polymerization catalyst.
R ¹ R ² R ³ B (1)
R ⁴ R ⁵ B (OR ⁶ ) (2)
R ⁷ R ⁸ BOBR ⁹ R ¹⁰ (3)
(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ may be the same or different and each has 1 to 18 carbon atoms. R ¹ , R ² or R ⁴ , R ⁵ may be linked to form a ring. A process for producing an ethylene-based polymer comprising polymerizing ethylene alone or copolymerizing ethylene and an α-olefin using the organoboron-treated fluorinated chromium polymerization catalyst according to claim 1. An ethylene-based polymer obtained by the method for producing an ethylene-based polymer according to claim 2, having an HLMFR of 1 to 100 g / 10 min and a density of 0.930 to 0.970 g / cm ^3. Polymer. A large blow, which is obtained by the method for producing an ethylene-based polymer according to claim 2 and has an HLMFR of 1 to 15 g / 10 minutes and a density of 0.940 to 0.960 g / cm ^3. Ethylene polymer for product molding. A blow molded product molded from the ethylene polymer according to claim 3. A large blow-molded product molded from the ethylene-based polymer for molding a large blow product according to claim 4. The large-sized blow-molded container according to claim 6, wherein creep resistance, impact resistance, and moldability are improved.

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