JPH0318644B2 - - Google Patents

Description

[Detailed description of the invention]

[] Object of the Invention The present invention relates to a method for producing an ethylene copolymer. More specifically, ethylene and α-olefin are co-co-produced in at least two stages using a catalyst system obtained from (A) a solid catalyst component containing at least magnesium atoms, halogen atoms, and titanium atoms and (B) an organoaluminum compound. This invention relates to a method for producing an ethylene copolymer that is characterized by polymerization, and aims to provide an ethylene copolymer that has a wide molecular weight distribution and excellent moldability and environmental stress cracking resistance. It is something. [] BACKGROUND OF THE INVENTION In the production of polyolefins that are flexible and have excellent resistance to environmental stress cracking, polyolefins with narrow molecular weight distributions (e.g., ethylene-based polymers) can be obtained if the injection speed of the extruder is high. The molding exhibits an irregular surface. Therefore, polymers with a broad molecular weight distribution are desired for extrusion processing to produce, for example, bottles, films, sheets, cables, pipes, and the like. In addition, in order to mold polyolefin into bottles, films, sheets, cables, etc., it must have excellent tear strength. In order to produce a molded article with excellent tear strength, it is necessary to use a polyolefin with a high molecular weight. When a molded article as described above is molded using a polyolefin having a high molecular weight, the tear strength is good, but the moldability is deteriorated. Furthermore, the surface of the molded product becomes irregular (shark skin, streaks, avatars, etc. occur on the surface). For these reasons, ethylene is homopolymerized or ethylene and α-olefin are copolymerized using a catalyst system obtained from titanium trichloride or its eutectic and an organoaluminum compound, resulting in a wide molecular weight distribution and good moldability. In addition to this, many ethylene polymers have been proposed that have excellent mechanical properties as described above. However, when an ethylene polymer is produced using the above catalyst system, the polymerization activity is low, so if the catalyst residue is not removed, the catalyst residue will cause rust in equipment such as molding machines. Furthermore, the molded product deteriorates and becomes discolored. For this,
It is necessary to remove catalyst residues remaining on the polymer after polymerization. In recent years, a catalyst system obtained from a solid catalyst component containing magnesium atoms, halogen atoms, and titanium atoms and an organoaluminum compound is a highly active olefin polymerization catalyst, which simplifies the process of removing catalyst residue after polymerization. It is also known that it can be done, or it can be omitted. It has been reported that when ethylene is homopolymerized or ethylene and α-olefin are copolymerized using the above catalyst system, the resulting ethylene polymer has a narrow molecular weight distribution; Many efforts are being made to expand it. However, the molecular weight distribution of the obtained ethylene polymer is not necessarily wide enough, and the moldability is not good, so it is difficult to say that it is satisfactory for molding into bottles, films, sheets, cables, pipes, etc. [] Structure of the Invention Based on the above, the present inventor has conducted various searches to obtain an ethylene polymer that does not have these problems. and (B) an organoaluminum compound, ethylene and α-olefin are copolymerized in at least two steps to produce an ethylene-based copolymer [hereinafter referred to as "copolymer ()"]. ]
(1) In at least one of the steps, the "High Load Melt Index" (hereinafter referred to as "HLMI") is 0.03 to 10 g/10 minutes, and the density is 0.890 g/cm ³ or 0.905
( ² ) in at least one other step, the melt index (hereinafter referred to as "M.I.") is from 10 to 5000 g. /10 minutes and a density of 0.890 to 0.940 g/ ^cm3 [hereinafter referred to as "copolymer ()"] 20 to 80 parts by weight is produced, and the MI is 0.02 to 30 g/10 minutes. The present inventors have discovered that by producing a copolymer with a density of 0.890 to 0.935 g/cm ³ , an ethylene polymer that solves all of these problems can be obtained, and the present invention has been achieved. . [] Effects of the invention As mentioned above, the copolymer () of the present invention
HLMI and density and MI of copolymers ()
Due to the special characteristics of the copolymer and density, the finally obtained copolymer exhibits the following characteristics (effects). (1) When molding the copolymer, the moldability is good. Therefore, even when the molding temperature is low, the molding pressure does not increase. As a result, the cooling time becomes shorter and the molding cycle can be shortened. Furthermore, rough skin and melt fracture of the molded product are less likely to occur even at high molding speeds. (2) The molded product has good environmental stress cracking. Therefore, it shows good resistance even under conditions where it comes into contact with surfactants (detergents), alcohol, and salad oil. (3) The molded product has good gloss. (4) Great bass impact resistance. (5) The transparency of the molded product is excellent. (6) Good chemical resistance. (7) Since the polymerization activity is high, very little catalyst residue remains in the resulting copolymer, and the process for removing catalyst residue can be simplified or omitted. Due to the small amount of catalyst residue, the color and odor of the copolymer are good even without removing the catalyst residue. Therefore, the amount of additives used can also be reduced. [] Detailed Description of the Invention (A) Solid Catalyst Component The solid catalyst component used to produce the ethylene copolymer of the present invention contains a magnesium atom, a halogen atom, and a titanium atom. The solid catalyst component is obtained by treating a magnesium-containing compound with a trivalent and/or tetravalent titanium compound. In this treatment, only the magnesium compound and the titanium compound may be treated, but the magnesium compound and the electron-donating organic compound may be treated in advance, and the resulting treated product and the titanium compound may be treated. Further, the magnesium compound, the titanium compound, and the electron-donating organic compound may be treated (they may be treated simultaneously or separately). Furthermore, the magnesium-based compound and the electron-donating organic compound may be treated in advance, and the resulting treated product may be treated with the titanium-based compound and the electron-donating organic compound. In addition, when treating with any of the above treatment methods, it may be treated together with an alkyl metal compound described below, or it may be further treated with an alkyl metal compound before or after the treatment. (1) Magnesium-based compounds Preferable magnesium-based compounds used to produce the solid catalyst component include magnesium-based compounds represented by the following formulas [formula () and formula ()], as well as magnesium oxide and magnesium hydroxide. can be given. Mg(OR ¹ ) mX ¹ _2-n () MgR ² _o X ² _2-o () In formulas () and (), m is 0, 1 or 2, and n is 1 or 2. . R ¹ and R ² are hydrogen atoms or hydrocarbon groups selected from the group consisting of aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups having at most 16 carbon ^atoms ; and X ² is a halogen atom.
In formulas () and (), R ¹ and R ² are preferably hydrogen atoms, alkyl groups having at most 12 carbon atoms, and phenyl groups, and X ¹ and X ² are chlorine atoms, bromine atoms, and iodine atoms. are preferred, with chlorine and bromine atoms being particularly preferred. Among the magnesium compounds represented by the formula ( ), representative examples of preferred compounds include magnesium chloride, magnesium bromide, magnesium ethylate, magnesium butyrate, and hydroxymagnesium chloride. Also,()
Among the magnesium compounds represented by the formula, representative examples of preferred compounds include butyl ethylmagnesium, dibutylmagnesium, ethylmagnesium chloride, butylmagnesium chloride,
Mention may be made of phenylmagnesium chloride, ethylmagnesium bromide, butylmagnesium bromide and phenylmagnesium bromide. (2) Titanium compound The titanium compound used to produce the solid catalyst component is a compound containing trivalent and/or tetravalent titanium. Typical examples include tetravalent titanium compounds represented by the formula () and titanium tetrachloride obtained by reducing them with metals (e.g., metallic titanium, metallic aluminum), hydrogen, or organoaluminum compounds. Examples include titanium trichloride and a eutectic of titanium trichloride. Ti ⁽ _OR ^{3 )} l A hydrocarbon group selected from the group consisting of aromatic hydrocarbon groups.
In formula (), R ³ is preferably an alkyl group having at most 6 carbon atoms, and X ³ is preferably a chlorine atom or a bromine atom, particularly preferably a chlorine atom. Among the tetravalent titanium compounds represented by the formula (), representative examples of preferred ones include titanium tetrachloride, methoxytitanium trichloride, ethoxytitanium trichloride, butoxytitanium trichloride, dimethoxytitanium dichloride, and diethoxytitanium dichloride. , triethoxytitanium trichloride, tetraethoxy and tetrabutoxytitanium. (3) Electron-donating organic compounds, etc. In producing the solid catalyst component used in the present invention, electron-donating organic compounds and compounds such as the inorganic compounds and alkyl metal compounds described below are not necessarily required, but the solid catalyst components The electron-donating organic compound used in the production of is an organic compound having at least one polar group, and is generally called a Lewis base. This electron-donating organic compound is well known as a modifier for polymerization activity, crystallinity, etc. for obtaining an olefinic polymerization catalyst. Representative examples of the electron-donating organic compounds include the following saturated or unsaturated aliphatic, alicyclic, or aromatic compounds. The compound is preferably a chain or cyclic ether compound [having at most 24 carbon atoms (for example, diethyl ether, di-n-
Butyl ether, di-isoaluminum ether, di-
hexyl ether, ethoxybenzene, diphenyl ether)], carboxylic acid compounds [preferably those with at most 18 carbon atoms (e.g. benzoic acid, lactate, acetic acid, stearic acid)], monovalent or polyvalent alcohol-based compounds or phenol-based compounds [those having at most 18 carbon atoms are preferred (for example, ethyl alcohol, n-butyl alcohol, phenol, p-methylphenol, ethylene glycol)], the above-mentioned carboxylic acid-based compounds anhydrides (e.g., acetic anhydride, phthalic anhydride, benzoic anhydride)], ester compounds obtained from the carboxylic acid compounds and alcohol-based compounds or phenol-based compounds (e.g., ethyl benzoate, γ-butyrolactone, phenyl acetate, ethyl acetate, butyl benzoate), aldehyde compounds [those having at most 18 carbon atoms are preferred.
(e.g. benzaldehyde, butyraldehyde,
acrylic aldehyde, cinnamaldehyde)]. Ketone compounds [preferably those with a total carbon number of at most 24 (e.g., acetone, benzophenone, acetophenone, cyclohexanone)], halide compounds of the above carboxylic acids (e.g., acetyl chloride, benzoyl chloride, benzoyl bromide) , cyclohexanecarbonyl chloride), silicate ester compounds with at most 24 carbon atoms (e.g.
Tetramethyl silicate, tetraethyl silicate, tetracresyl silicate, trichloromethyl silicate)] mono- or polysiloxane [those with a total silicon content of at most 1000 are preferred. ],
Amine-based compounds [those having a total number of carbon atoms of at most 36 are preferred. (e.g. tributylamine,
dibutylamine, aniline, N,N-dimethylaniline)], amide compounds [even if the total number of carbon atoms is large
36 are preferred (for example, N,N-dimethylbenzamide, acetamide, N,N-dimethylhexanoicamide), phosphate ester compounds or phosphite compounds [with a carbon number of at most 24 (For example, triphenyl phosphite, diphenyl phosphate chloride, triethyl phosphate, triphenyl phosphate). Moreover, any compound other than the electron-donating organic compound used to produce the solid catalyst component may be used as long as it is not a catalyst poison for the solid component. Among these compounds, as inorganic compounds,
Examples include halides of Group 1 or Group 3 of the periodic table (for example, halides of aluminum, silicon, zinc, etc.), sulfates, nitrates, sulfites, and nitrites. Further, among the alkyl metal compounds, preferable ones include alkyl metal compounds containing at least one metal among the metals of group a, group a, group b, and group a of the periodic table (in addition to an alkyl group, It may contain any one of an alkoxy group, a halogen atom, and a hydrogen atom.
It is preferred that the alkyl group and alkoxy group have at most 15 carbon atoms. (4) Treatment method In order to produce the solid catalyst component, a method for treating the magnesium compound and the titanium compound, or these compounds and an electron-donating organic compound, involves mechanically pulverizing these compounds. (hereinafter referred to as the "co-grinding method") and a method of contacting in an inert solvent or in the absence of an inert solvent (when the processed material is liquid) (hereinafter referred to as the "contact method"). can give. As the co-pulverization method, a commonly used method of co-pulverizing a magnesium-based compound and a titanium-based compound, or these compounds and an electron-donating organic compound to produce a solid catalyst component for olefin polymerization may be applied. Generally, ball mill,
Co-pulverization may be carried out using a pulverizer such as a vibrating ball mill, an impact pulverizer, or a colloid mill at around room temperature in an atmosphere of an inert gas (eg, nitrogen, argon). Normally, it is not necessary to perform measures such as cooling, but if heat generation is significant due to this co-pulverization, cooling may be performed for convenience of operation. Although the time required for co-pulverization cannot be absolutely defined depending on the performance of the crusher, etc., it is necessary to at least make the material to be crushed fine enough to withstand use. Although the obtained pulverized material can be used even if it is not in a completely uniform state, it is preferable that it be in a uniform state. Therefore, the co-milling time is generally between 5 minutes and 24 hours. In addition, the contact method is a method of processing in the presence or absence of an inert solvent (when one of the processed materials is a liquid and can be stirred as a liquid). The inert solvent used in this process is dry (contains no water) and typically includes aliphatic hydrocarbons (e.g., n-hexane, n-heptane, n-heptane, −
octane), alicyclic hydrocarbons (e.g., cyclohexane, dimethylcyclohexane), aromatic hydrocarbons (e.g., benzene, toluene, xylene), and halides of these hydrocarbons (e.g., tetrachlorinated hydrocarbons, trichloroethylene,
(chlorobenzene). In the contact treatment, although the treatment can be carried out in an inert solvent as described above, at least one of the electron-donating organic compounds, alkyl metal compounds, titanium-based compounds, and magnesium-based compounds is a liquid substance, When it is in a liquid state and can be stirred, it can also be treated in the absence of an inert solvent. In this contacting method, the ratio of solid to liquid in the treatment system is at most 500 g. In addition, the contact temperature varies depending on the type and proportion of the contact material, the contact time, and other conditions, but
Usually room temperature (20℃) to 250℃. The contact time varies depending on the type and proportion of the contact material, the contact temperature, and other conditions, but is generally 5 minutes or more.
It is 24 hours. In either of the above co-pulverization methods and contact methods, the ratio of the titanium-based compound to 1 mol of the magnesium-based compound is generally 0.02 to 20 mol. Further, when an electron-donating organic compound is used, the ratio of the electron-donating organic compound to 1 mol of the magnesium compound is usually at most 50 mol. Furthermore, if an alkyl metal compound is used, the ratio of alkyl metal compound to 1 mol of magnesium-based compound is generally at most 10 mol. (5) Purification (post-treatment) The solid catalyst component obtained as described above is purified by using the inert solvent used in the treatment method to remove the titanium compounds, magnesium compounds, and electron-donating organic compounds remaining in the solid catalyst component. The compound and alkyl metal compound (if used) are purified by washing until no longer observed in the wash solution and removing the inert solvent used. This washing method may be carried out by removing the supernatant by decanting or filtering. The content of titanium atoms in the solid catalyst component obtained as described above is generally 0.01 to 30% by weight. In addition, the content of magnesium atoms is 0.1 to 30% by weight, and the content of halogen atoms is at most 90% by weight.
Weight%. (B) Organoaluminum compound Among the organoaluminum compounds used in the copolymerization of ethylene and α-olefin in the present invention, the general formula of typical ones is the following formula [formula (),
() and ())]. AlR ⁴ R ⁵ R ⁶ () R ⁷ R ⁸ Al-O-AlR ⁹ R ¹⁰ () AlR ¹¹ _1.5 X ⁴ _1.5 () In () formula, () formula and () formula,
R ⁴ , R ⁵ and R ⁶ may be the same or different and are an aliphatic, alicyclic or aromatic hydrocarbon group having at most 12 carbon atoms, a halogen atom or a hydrogen atom, but at least One is a hydrocarbon group, R ⁷ R ⁸ R ⁹ and R ¹⁰ may be the same or different and are the hydrocarbon group, R ¹¹ is the hydrocarbon group, and X ⁴ is a halogen atom. Typical organoaluminum compounds represented by the formula () include trialkylaluminum such as triethylaluminum, tripropylaluminum, tributylaluminum, trihexylaluminum and trioctylaluminum, diethylaluminum hydride and diisobutylaluminum hydride. Examples include alkyl aluminum hydride, diethyl aluminum chloride, and diethyl aluminum bromide. Further, among the organoaluminum compounds represented by the formula (), representative examples include alkyldialumoxanes such as tetraethyldialumoxane and tetrabutylalumoxane. Further, among the organoaluminum compounds represented by the formula (), ethylaluminum sesquichloride is a typical example. In carrying out the present invention, the solid catalyst component and the organoaluminum compound, or a reactant or mixture of these with an electron-donating organic compound, etc., are separately introduced into a reactor (polymerization vessel) used in the first step described below. However, two or all of them may be mixed in advance. Alternatively, it may be used after being diluted in advance with an inert solvent used as a solvent in the polymerization described later. (C) Production of copolymer () and copolymer () (1) Solid catalyst component and organoaluminium Copolymer () and copolymer () of the present invention
There is no limit to the amount of the solid catalyst component and organoaluminum compound used in the production of the solid catalyst component and organoaluminum compound obtained as described above, but 1 mg to 1 g of the solid catalyst component and 0.1 g of the solid catalyst component and 0.1 g of the inert organic solvent used in the polymerization. A proportion of organoaluminum compound used of ˜10 mmol is preferred. The amount of organoaluminum compound used is generally 1 to 1 per atomic equivalent of titanium metal contained in the solid catalyst component.
In the range of 1000 moles. (2) α-Olefin α used to produce the copolymer of the present invention
-Olefins are hydrocarbons with a double bond at the end, and the number of carbon atoms is at most 12. Representative examples include propylene, butene-1,4
-Methylpentene-1, hexene-1 and octene-1. (3) Other copolymerization conditions Copolymerization is carried out by dissolving ethylene and α-olefin in an inert solvent. In this case, a molecular weight regulator (generally hydrogen) may be present together if necessary. The polymerization temperature is generally from -10°C to 300°C, and practically from room temperature (25°C) to 270°C. In addition, the type of polymerization solvent and ethylene and α
- Regarding the ratio of use to olefin, the conditions used in the production of general ethylene polymers may be applied. Furthermore, the configuration of the polymerization reactor, the method of controlling polymerization, the post-treatment method, the ratio of monomers (ethylene and α-olefin) to the inert organic solvent used in polymerization, the ratio of organoaluminum compounds, and the inert organic solvent. Regarding the type of catalyst, there are no limitations inherent to this catalyst system, and all known methods can be applied. Copolymer () and copolymer () of the present invention
To produce each copolymer, each copolymer may be produced in only one step or in two or more steps. Furthermore, the copolymer () does not necessarily have to be produced in the first step. Further, there is no need to alternately produce copolymer () and copolymer (). Furthermore, copolymer () → copolymer ()
→ Copolymer () → Copolymer () may be produced arbitrarily. (D) Production of copolymer (2) To produce the copolymer (2) of the present invention, ethylene and the α-olefin described above are copolymerized under the copolymerization conditions described above. At this time, in order to carry out the copolymerization in an inert solvent, the copolymerization may be carried out by dissolving at least 10% by weight of α-olefin with respect to the ethylene dissolved in the solvent. Furthermore, the molecular weight modifier (generally hydrogen) used to adjust the molecular weight of the copolymer has a weight ratio of the molecular weight modifier to ethylene that is smaller than the copolymer conditions used in the production of the copolymer () described below. be used as such. The copolymer () obtained in this way
HLMI (according to JIS K-6760, measured at a temperature of 190℃ and a load of 21.6Kg) is 0.03 to 10g/
10 minutes, particularly preferably 0.3 to 5 g/10 minutes.
Further, the density is from 0.890 g/cm ³ to less than 0.905 g/cm ³ , preferably from 0.895 to 0.905 g/cc. The copolymer () produced at this stage
If the HLMI value is less than 0.03 g/10 minutes, it becomes virtually impossible to mix with the copolymer () produced in other steps, causing deterioration of the physical properties of the final product. Also, if the HLMI value is greater than 10 g/10 min, the molecular weight distribution cannot be broadened enough to be effective in improving the moldability of the final product. Further, if the density of the copolymer is higher than 0.905 g/cm ³ , the environmental stress cracking resistance is lowered, and the transparency and low-temperature impact strength are lowered, which is not preferable. In addition, copolymers with a density lower than 0.890 g/cm ³ tend to adhere to each other, making it difficult to handle them as a powder. (E) Production of copolymer () In producing the copolymer () of the present invention,
Although it is not always necessary to produce the copolymer () after producing the copolymer (), if the copolymer () is produced after producing the copolymer (), the resulting copolymer The product containing () (containing a catalyst system, monomer, etc.) may be subsequently copolymerized under the conditions described below. In addition, when producing the copolymer () after producing the copolymer (), the product containing the obtained copolymer () is subsequently copolymerized as described above to produce the copolymer (). ) can be manufactured. In any of the above methods, the second stage copolymerization may be carried out in the polymerization vessel used in the first stage copolymerization, or the product containing the copolymer may be transferred to another polymerization vessel. You may do so. To carry out this copolymerization, the dissolved amount of α-olefin used is 10% by weight or more of the dissolved amount of ethylene. In addition, in order to ensure that the MI of the resulting copolymer falls within the range described below, if the copolymer was produced in the previous step, the amount of molecular weight regulator used in the copolymerization may be further increased. . The density of the copolymer () obtained at this stage is 0.890-0.940 g/cc, especially 0.890-0.940 g/cc.
0.935g/cc is preferred. Also MI (JIS K-6760
(according to
minutes is preferred. Furthermore, the ratio of HLMI to MI (HLMI/MI) of the copolymer () obtained at this stage is generally from 20 to 45. If the density of the copolymer () obtained in this stage of copolymerization is higher than 0.940 g/cc, the final product will have less flexibility and will have poor environmental stress cracking resistance. Furthermore, it results in a decrease in transparency and low-temperature impact strength. On the other hand, if the density is lower than 0.890 g/cm ³ , the final product (molded product) tends to be sticky and its commercial value is significantly reduced. Furthermore, if the MI of the copolymer is lower than 10 g/10 min, the molecular weight distribution cannot be broadened to an extent effective for improving the moldability of the final product. On the other hand, when the MI exceeds 5000 g/10 minutes, the final product tends to become sticky.
This phenomenon becomes more pronounced as the density of the copolymer produced at this stage becomes lower and the MI becomes higher, so it is not desirable for the MI to exceed 5000 g/10 minutes. (F) Final copolymer and its use The density of the final copolymer obtained as described above is generally 0.890 to 0.935 g/cm ³ . Moreover, MI is 0.02 to 30 g/10 minutes, particularly preferably 0.05 to 20 g/10 minutes. Furthermore, the HLMI/MI of this copolymer is between 50 and 400.
The content of the copolymer () in the final copolymer is 20 to 80% by weight, preferably 25 to 75% by weight. If the proportion of the copolymer () in the final copolymer is outside the range of 20 to 80% by weight, the molecular weight distribution of the final copolymer will not be effectively expanded. The catalyst system used in the present invention has higher polymerization activity per transition metal compound than a catalyst system consisting of a transition metal compound (unsupported on a carrier) and an organoaluminium compound. Therefore, it is not necessary to remove the catalyst residue remaining in the polymer, but depending on the intended use of the polymer, the catalyst residue may be removed by a simple method used in this field. The catalyst system used in the present invention is desirably highly active to the extent that the step of removing catalyst residues can be substantially omitted. Particularly desirable is a catalyst system that allows the amount of titanium oxide (TiO ₂ ) remaining in the copolymer produced in the first stage copolymerization to be at most 500 ppm. In addition, it is preferable that the molecular weight distribution of the copolymer () is not too broad, and the molecular weight distribution scale is HLMI/
Expressed in MI, even if the value of HLMI/MI is large,
45 is preferred. This is because the stickiness of the final copolymer (which causes bleeding in films and causes odor in bottles) is due to the extremely low molecular weight portion produced during the production of the copolymer. In order to cause
If the value of HLMI/MI is at most 45, the final product has good physical properties. Therefore, when producing high MI, the performance of the catalyst system used is
It is necessary to select one whose HLMI/MI falls within the above range. As mentioned above, the copolymer obtained by the present invention not only has good moldability, but also has excellent environmental stress cracking resistance, gloss, low-temperature impact resistance, and
Due to its excellent transparency, it can be formed into films, sheets, pipes, containers, etc. using extrusion molding and blow molding methods used in the field of ethylene polymers. . The copolymer of the present invention obtained by the above molding method can be used in various fields, but typical applications include bottles,
Examples include films, sheets, pipes, and cables. [] Examples and Comparative Examples The present invention will be explained in more detail below using Examples. In the Examples and Comparative Examples, haze was measured using a press piece with a thickness of 0.5 mm using a haze meter (manufactured by Suga Test Instruments Co., Ltd., trade name HGM-2D). The examples illustrate the preparation method and properties of the copolymers in at least two stage polymerizations carried out under different polymerization conditions. The copolymerization was carried out in 100 polymerization vessels (autoclaves). Because of such a small-scale experimental facility, for convenience, the operation of at least two polymerization vessels was replaced by changing the polymerization conditions of the polymerization vessels after a certain period of time, instead of changing the contents to another polymerization vessel. In each Example and Comparative Example, each compound used in the production and polymerization of the solid component and solid catalyst component (for example, inert solvent, ethylene, α
-Olefin, titanium compound, alkyl metal compound, magnesium magnesium, solid component,
The organic aluminum compound (organoaluminum compound) used was one from which water had been substantially removed in advance. Furthermore, the production and polymerization of the solid component and solid catalyst component were essentially moisture-free and conducted under a nitrogen atmosphere. Example 1 [(A) Production of solid component (1) and solid catalyst component (A)] Anhydrous magnesium chloride (commercially available anhydrous magnesium chloride was heated at about 500°C in a dry nitrogen stream)
(obtained by heating and drying for 15 hours)
20.0 g and 6.0 g of titanium tetrachloride were placed in a vibrating ball mill container (stainless steel, cylindrical, internal volume: 1
, the apparent volume of a porcelain ball mill with a diameter of 10 mm.
50% filling). This was attached to a vibrating ball mill with an amplitude of 6 mm and a frequency of 30 Hz, and co-pulverized for 8 hours until a uniform co-pulverized product [titanium atom content
5.87% by weight, magnesium atom content 19.4% by weight, chlorine atom content 74.7% by weight or less.
(1)'' was obtained. After putting 15.0g of this solid component (1) into a 500ml flask, add 100ml of toluene to suspend it, and add 100ml of pyridine over 2 hours while stirring thoroughly at room temperature (about 25°C). dripped. After the dropwise addition was completed, the temperature of the treatment system was raised to 80°C, and the mixture was stirred at this temperature for 2 hours. Then, the treatment system was again cooled to room temperature, and 20.0 ml of a toluene solution of triisobutylaluminum (concentration 1.0 mol/l) was added dropwise over 1 hour. After the dropwise addition was completed, the temperature of the treatment system was raised to 60°C, and the mixture was sufficiently stirred at this temperature for 2 hours. Then, the liquid containing the product was cooled to room temperature, and the product was thoroughly washed with n-hexane. (until almost no titanium atoms are recognized in the cleaning solution)
Thereafter, drying was carried out for 3 hours under reduced pressure at a temperature of 60°C. As a result, a solid substance [hereinafter referred to as “solid catalyst component”]
(A)” was obtained. [(B) First stage copolymerization] The solid catalyst component (A) obtained in (A) was placed as the main catalyst in a stainless steel autoclave of 609
mg, and 10.0 g of triethylaluminum was added. After adding 30Kg of isobutane as an inert solvent, the autoclave was closed and the internal temperature was raised to 80°C. Next, after adding hydrogen to 0.14Kg/cm ² (gauge pressure), 5.1Kg of butene-1 was pressurized with ethylene until the partial pressure of ethylene was 5.0Kg/cm ²
Ethylene was fed until the pressure reached (gauge pressure), and copolymerization of ethylene and butene-1 was carried out for 15 minutes. [(C) Second stage copolymerization] After the completion of the first stage copolymerization, 4.9% hydrogen
Kg/cm ² (gauge pressure) was further added, and copolymerization of ethylene and butene-1 was carried out for 80 minutes under the same polymerization conditions as in (B). Then, the copolymerization was terminated by releasing the gas contained in the polymerization system to the outside of the system. The obtained copolymer was dried at a temperature of 60° C. under reduced pressure for 12 hours. As a result, 8.1 kg of copolymer was obtained. That is, the polymerization activity was 1690 g/g-solid catalyst component (A), time, and ethylene partial pressure (Kg/ ^cm2 ). [(D) Physical properties of final copolymer] The bulk density of the copolymer obtained in (B) and (C) was 0.35 g/cm ³ and the density was 0.913 g/cm ³ . Also, MI is 1.5g/10 minutes, and HLMI/
The MI was 88, indicating a wide molecular weight distribution and good moldability. As a stabilizer for this copolymer
0.15% by weight of tetrakis [methylene-3-
(3′.5′-di-tertiary-butyl-4′-hydroxyphenyl)propionate] methane, 0.20% by weight of distearylthiodipropionate and 0.10% by weight of calcium stearate were added and preheated to 170°C. Mixed uniformly for 5 minutes using a set roll (3 inch diameter). Using a press set at 170°C, the resulting mixture was packed at 100Kg/
A press sheet with a thickness of 0.5 mm was produced by hot pressing under a pressure of cm ² . The haze of the obtained press sheet was 35%. The copolymer obtained as described above was added with 0.02% by weight of 2,6-di-di-2,6-di-2,6-di-1 as a stabilizer based on the copolymer.
40 mm internal diameter with addition of tertiary-butyl-p-cresol and 0.3% by weight calcium stearate
Pellets were made by kneading at 200°C using an extruder. Next, blow molding machine [product name Plako SV,
A 300 c.c. round bottle was blow-molded using an inner diameter of 45 mm and a L/D of 22. The molding conditions are as follows: Resin temperature: 205℃ Nozzle mandle: 9mm〓-14mm〓 Screw rotation speed: 40 revolutions/min Mold cooling temperature: 20℃ Cooling time: 15 seconds Extrusion amount: 8.21Kg/hour Obtained by blow molding Roughness on the surface of the round bottle was observed with the naked eye. The condition of rough skin was very good. Comparative Example 1 Solid catalyst component (A) produced in (A) of Example 1
and 10.0 g of triethylaluminum were placed in an autoclave similar to that used in Example 1 (B). After adding 30Kg of isobutane, change the partial pressure of hydrogen to 1.4Kg/cm ² and further increase the polymerization time.
Only the first stage copolymerization of ethylene and butene-1 was carried out under the same conditions as in Example 1 (B) except that the time was changed to 60 minutes. After the first stage copolymerization was completed, the copolymerization was completed and dried in the same manner as in Example 1 (C). As a result, 10.9 kg of copolymer was obtained.
That is, the polymerization activity is 2080g/g-solid catalyst component
(A)・Time・Ethylene partial pressure (Kg/cm ² ). The bulk density of this copolymer is 0.37 g/cc;
It was 0.923g/cc. Moreover, MI was 1.2 g/10 minutes, and HLMI/MI was 26. That is,
The copolymer had a narrow molecular weight distribution and poor moldability. Examples 2 to 6, Comparative Examples 2 to 4 Solid catalyst component (A) produced in (A) of Example 1
(However, in Example 5, the amount of solid catalyst component (A) used was 1.05 g), polymerization time,
Copolymerization of ethylene and α-olefin was carried out in the same manner as in Example 1 (B), except that the polymerization temperature, the added α-olefin and hydrogen were changed as shown in Table 1. The partial pressure and the amounts of isobutane and triethylaluminum used were the same as in Example 1 (B)]. The partial pressure of ethylene in the slurry containing each copolymer obtained by the first stage copolymerization as described above was 5.0 Kg/cm ² (gauge pressure).
Ethylene was added so that the polymerization time, polymerization temperature, amount of hydrogen added, and α
- The second stage copolymerization of ethylene and α-olefin was carried out under polymerization conditions as shown in Table 1, with the amount and type of olefin (in some cases not added). Then, in the same manner as in Example 1 (C), each copolymerization was completed and each obtained copolymer was dried. The yield of each copolymer obtained, the polymerization activity determined by calculation, the bulk density, density, MI and HLMI/MI of each copolymer, and the results of Example 1.
Table 2 shows the haze of each press sheet produced in the same manner as (D). Further, a stabilizer and calcium stearate were added to each copolymer thus obtained in the same manner as in Example 1, and pellets were prepared by kneading, and then blow molding was performed in the same manner as in Example 1. . (However, Comparative Example 4 could not be blow molded). The roughness of the surface of each round bottle thus obtained was observed with the naked eye. The results are shown in Table 2. In Table 2, the state of rough skin is shown as follows. ◎ Very good 〇 Good △ Poor × Very bad

【table】

[Table] Reference Examples 1 to 8 The amount of solid catalyst component (A) used in the first stage copolymerization of Examples 1 to 6 and Comparative Examples 3 and 4 was changed as shown in Table 3-1. teeth,
Copolymerization of ethylene and α-olefin was carried out under exactly the same conditions as in the first stage copolymerization of Examples 1 to 6 and Comparative Examples 3 and 4. Table 3-1 shows the yield of each copolymer of ethylene and α-olefin obtained, the polymerization activity determined by calculation, and the MI, HLMI/MI, density, and bulk density of each copolymer. . Reference Examples 9 to 16 Solid catalyst component (A) used in the second stage copolymerization of Examples 1 to 6 and Comparative Examples 3 and 4
Examples 1 to 5 and Comparative Examples 3 and 4 except that the amount used was changed as shown in Table 3-2.
Copolymerization of ethylene and α-olefin was carried out under exactly the same conditions as (The amount of hydrogen used is the sum of the amounts of hydrogen used in the first-stage copolymerization and the second-stage copolymerization.) of hydrogen). The yield of each copolymer of ethylene and α-olefin obtained, the calculated polymerization activity, and the MI, HLMI/
MI, density and bulk density are shown in Table 3-2. Reference Examples 1 to 8 and Reference Examples 9 to 8 above
As a result of 16, the production proportion of each copolymer obtained by the first stage copolymerization in the total produced polymer according to Examples 1 to 6 and Comparative Examples 3 and 4 is shown in Table 3-3. It is estimated that the percentage shown is

【table】

【table】

【table】

Claims (1)

[Scope of Claims] 1. Ethylene and α-olefin are combined using a catalyst system obtained from (A) a solid catalyst component containing at least a magnesium atom, a halogen atom, and a titanium atom, and (B) an organoaluminum compound. In producing an ethylene copolymer by copolymerizing in steps, (1) in at least one of the steps,
High Road Melt Index is 0.03
~10g/10min, and the density is 0.890g/
cm ³ to less than 0.905 g/cm ³ copolymer 80
(2) in the second stage, the melt index is 10 to 5000 g/10 minutes and the density is
Copolymer 20 to 0.905 to 0.940 g/ ^cm3
80 parts by weight, a melt index of 0.02 to 30 g/10 min, and a density of 0.890 to 0.935 g/cm ³ . Method.