JPH0358367B2 - - Google Patents

Description

[Detailed description of the invention]

[] Background of the Invention (1) Technical Field The present invention relates to a solid catalyst component to constitute a catalyst for stereoregular polymerization of α-olefins. Many proposals have already been made regarding methods for producing solid catalysts for olefin polymerization that contain magnesium, titanium, halogen, and electron donors as essential components. Among them, MgX ₂ .
Japanese Patent Publication No. 53-40632 using mH ₂ O (M is the number of 1.2 m 0.42) and MgX ₂ nROH (ROH
is an alcohol, and n is a number of 6n10 ^-6 ). Furthermore, a method for co-precipitating an ether complex of titanium tetrahalide and an ether complex of magnesium halide from a solution using an aliphatic ether or a cyclic ether is disclosed in Japanese Patent Application Laid-open No. 1973-
It is known from Publication No. 131887. In this case, the molar ratio x of the electron donor to the sum of titanium and magnesium is expressed as 3>x>1. All of these prior art techniques are suitable for the production of polyethylene, as is clear from their examples. In fact, according to the inventors' additional experiments, it was found that even if a stereoregularity improver such as an organic acid ester was added, catalysts suitable for the stereoregular polymerization of α-olefins could easily be produced from these compounds. It cannot be obtained. In general, catalysts produced by solution precipitation can have extremely high polymer bulk densities and uniform particle size distributions if appropriate methods are used. Therefore, if a highly active catalyst suitable for the stereoregular polymerization of α-olefins could be obtained by this method, it would be of great benefit. By the way, the present inventors have already developed a catalyst obtained by improving the method using a titanium alkoxy compound as a solvent (Japanese Unexamined Patent Publication No. 58-32605) and a catalyst obtained using a phosphorus compound as a solvent (Japanese Unexamined Patent Publication No. 58-19307). It is known that extremely high performance can be achieved in the stereoregular polymerization of α-olefins. The present invention relates to improvements over these prior inventions. (2) Problems with the prior art A detailed study of the prior art as described above reveals that, for example, the catalyst disclosed in JP-A-50-131887 is suitable for the stereoregular polymerization of α-olefins. It is understood that the remaining amount of ether is too large. According to the studies conducted by the present inventors, the smaller the amount, the more preferable the result will be. However, attempts to reduce the ether by heating or reducing pressure were unsuccessful. On the other hand, in the case of water or alcohol and magnesium halide as mentioned above, if you adopt the method of dissolving and then precipitating,
MgX _{2.6H 2} O and MgX _2.6ROH , which precipitate containing many electron donors, can be heated or depressurized to reduce the values of m and n to about 1. However, such a method is not very preferable because it requires extra labor and may deteriorate the catalyst carrier. If a small amount of alcohol is brought into contact with anhydrous magnesium halide in a slurry state, a complex containing a relatively small amount of electron donor can be obtained. This does not mean that the characteristics of shape control are utilized. In order to improve these drawbacks, it is necessary to discover a solvent system that dissolves magnesium halide well and leaves an extremely small amount of magnesium halide in the precipitate after it has been precipitated. It is expected that the amount of the solid catalyst will not adversely affect stereoregularity control during olefin polymerization compared to water or alcohol, and more preferably the shape of the solid catalyst obtained by precipitation will increase the bulk density of the olefin polymer and reduce the particle size. Something that makes the distribution uniform is long-awaited. [] Summary of the Invention (1) Summary The present inventors have discovered a method for producing a high-performance catalyst that is extremely close to the above goals by using a mixture of an organic epoxy compound and an organic phosphorus compound as a solvent system, and have achieved the present invention. This is what I did. Therefore, the solid catalyst component for α-olefin polymerization according to the present invention is characterized by comprising a contact product of (A) and (B) as described below. (A) A magnesium halide solution prepared by dissolving magnesium halide in a solvent system consisting of an organic epoxy compound and an organic phosphorus compound, and titanium tetrahalide, and optionally, precipitated from this solution after contacting with an organic acid ester, D/(Ti+
D represents the total number of moles of the above epoxy compound, organic phosphorus compound and organic acid ester, Ti and Mg represent the number of moles of magnesium and titanium. ). (B) Titanium tetrahalide (2) Effect As shown in the examples below, the catalyst made from the solid catalyst component according to the present invention has high performance. It is thought that such an effect is realized by the unexpected critical contribution of each element of the solid catalyst component of the present invention. For example, one component of the solvent used in the present invention is an organic epoxy compound, and although this compound can be considered as a three-membered ring ether, the invention described in JP-A-50-131887 uses an organic epoxy compound as an ether. It is clear from the fact that organic epoxy compounds are not exemplified that this is not the case, and in fact, the results of the studies conducted by the present inventors show that the use of organic epoxy compounds alone does not result in good dissolution of magnesium halide. It is difficult to do so, and solid solvent components intentionally produced using a single solvent system provide only extremely inferior catalysts with low activity and low polymer bulk density, as shown in Reference Example 1. Further, a solvent system in which an organic epoxy compound and an organic phosphorus compound are combined can realize higher catalytic performance and better polymer bulk density and particle size distribution than a system using only a phosphorus compound. Although the appropriate reason for this combination is still not completely clear, it has been observed that the amount of titanium as a polymerization active species immobilized on the solid support is significantly increased compared to the phosphorus compound alone system. Furthermore, when polymer particles obtained by ordinary slurry polymerization are observed, particles that are more nearly spherical and have a larger diameter are obtained, and it is understood that the bulk density has been improved as a result. [] Detailed Description of the Invention (1) Magnesium Halide Solution This solution is made by dissolving magnesium halide in a solvent system consisting of an organic epoxy compound and an organic phosphorus compound. This is further processed to precipitate the precipitated solid (A). Here, "a solvent system consisting of an organic epoxy compound and an organic phosphorus compound" includes a case where a third solvent component is included within a range that does not impair the effects of the present invention, as described later. (1) Magnesium halide Magnesium dihalide is typical, and typical halogens are chlorine, bromine, and iodine. Magnesium dichloride is preferred. The dihalogenated magnesium may be a complex with water, alcohol, etc., or one of the halogens may be substituted with a hydrocarbyloxy group or a halohydrocarbyloxy group. In this case, the hydrocarbyl moiety usually has about 1 to 10 carbon atoms. (2) Organic epoxy compound Since the organic epoxy compound is used as a solvent component, it should be liquid by itself or when mixed with the organic phosphorus compound (and optionally a third solvent component). Specific examples of the organic epoxy compound that can be used in the present invention include oxides of alkenes or alkadienes or haloalkenes or haloalkadienes having about 2 to 8 carbon atoms, glycidol, ether of glycidol, and glycidol having about 1 to 6 carbon atoms. esters of mono- or dicarboxylic acids, and others. Specific compounds include ethylene oxide, propylene oxide, butene oxide, butadiene monoxide, butadiene oxide, epichlorohydrin, methyl glycidyl ether, diglycidyl ether, glycidyl acetate, and the like. (3) Organic phosphorus compound The organic phosphorus compound should also be a compound having the same liquid properties as described above for the organic epoxy compound. One group of specific examples of organophosphorus compounds that can be used in the present invention has the formula P(〓O) _p (R ¹ ) _q
(OR ² ) is expressed by _r . here,
R ¹ and R ² are each hydrocarbyl or halohydrocarbyl, p is 1 or 0, q and r are each 1-3, and q+r is 3. When q and r are plural, the plurality of R ¹ or R ² may not be the same. Symbol〓O is P-O when q=3
Indicates that the bond may be a semipolar bond. The hydroxycar (including the hydrocarbyl moiety of halohydrocarbyl) preferably has about 1 to 8 carbon atoms. Phosphorus compounds represented by such formulas include trihydrocarbyl or trihalohydrocarbyl esters of orthophosphoric acid and phosphorous acid, monohydrocarbyl or monohalohydrocarbyl dihydrocarbyl or dihalohydrocarbyl esters of orthophosphoric acid and phosphorous acid, and dihydrocarbyl or dihalohydrocarbyl esters of orthophosphoric acid and phosphorous acid. hydrocarbyl or dihalohydrocarbyl orthophosphoric acid and hydrocarbyl or halohydrocarbyl ester of phosphorous acid,
Preferably, there are those having at least one oxygen atom in addition to the phosphorus atom, such as trihydrocarbyl or trihalohydrocarbylphosphine and trihydrocarbyl or trihalohydrocarbylphosphine oxide. Specific compounds include trimethyl orthophosphate, triethyl orthophosphate, tripropyl orthophosphate, tributyl orthophosphate, trioctyl orthophosphate, triphenyl orthophosphate, trimethyl phosphite, triethyl phosphite, and phosphorous. tripropyl acid, tributyl phosphite, triphenyl phosphite, ethyl diethyl phosphate,
Dibutylbutyrate, dimethyl phosphite, butyl diethyl phosphite, triβ-chloroethyl orthophosphate, triβ-chloroethyl phosphite, tributylphosphine oxide,
Examples include triphenylphosphine oxide. (4) Preparation of solution If magnesium halide is used with a small particle size, it will be easily dissolved under stirring even at room temperature. However, in some cases, in order to prevent trace amounts of solids from remaining and adversely affecting the shape of the final solid catalyst component, heating to a temperature of about 100℃ may be required during or after the melting operation. preferable. During dissolution, an inert solvent such as hexane, heptane, benzene, toluene, 1,2
- It is also possible to add dichloroethane and other hydrocarbons or halohydrocarbons. The amounts of each component constituting the solution are as described below. (2) Precipitation The magnesium halide solution obtained in this way is treated with titanium tetrahalide,
A solid is precipitated. If an organic acid ester is also used when titanium halide is used,
The resulting catalyst has improved stereoregularity. In addition, in the present invention, regarding the precipitated solid, "the precipitated solid was precipitated from this solution after contact with a magnesium halide solution, titanium tetrahalide, and optionally an organic acid ester" means that these two or three components are present simultaneously or in stages. It means to come into contact with each other, and therefore, "after contact" also includes after a portion of each of the predetermined components has come into contact. (1) Titanium tetrahalide Titanium tetrachloride, titanium tetrabromide, and titanium tetraiodide are representative. Titanium tetrachloride is preferred. (2) Organic acid esters Organic acid esters to be used as necessary include esters of aliphatic carboxylic acids, such as α,β-unsaturated carboxylic acids, as well as aromatic carboxylic acids, especially benzoic acid, toluic acid, and anisyl acid. esters of acids, etc., esters of phenylacetic acid, esters of cyclohexanecarboxylic acid,
There are others. Among these, esters of aromatic carboxylic acids, phenyl acetic acid and cyclohexane carboxylic acid are preferred. The alcohol moiety constituting the ester is usually an alkyl group having about 1 to 8 carbon atoms. Specific compounds include methyl benzoate, ethyl benzoate, i-propyl benzoate, octyl benzoate, ethyl p-toluate, ethyl p-anisate, ethyl cyclohexanecarboxylate, and ethyl phenyl acetate. (3) Precipitation operation To obtain a precipitated solid by adding titanium tetrahalide to a magnesium compound solution,
A method of dropping titanium tetrahalide to obtain a solid immediately at a temperature of about 100°C, preferably 0 to 40°C, and a method of obtaining a solid immediately at a low temperature, for example -20 to -40°C,
There are two methods, one is to mix titanium halide to obtain a homogeneous mixture without any precipitation, and then gradually heat the mixture to obtain a solid powder. Both methods yield favorable results. Interestingly, when adopting the latter method, even if the organic acid ester is added to the homogeneous solution after adding the entire amount of titanium halide, a rather favorable result can be obtained. In other words, in either method, it is desirable to avoid adding organic acid esters after the solid has precipitated, as these organic acid esters will not be uniformly dispersed in the precipitated solid, but in this latter method, If the organic ester is added to a homogeneous solution, its homogeneous dispersion will be achieved. Whichever method is used, it is desirable that the precipitation be carried out slowly over time. Specifically, in the case of the latter instant precipitation by dropping, the time is 0.5 to 5 hours, preferably 1 to 3 hours.
It is preferable to drop titanium tetrahalide so that the precipitation is completed within a certain amount. In the latter heating precipitation method, the heating rate is 3°C/hour ~
100℃/hour, preferably 5℃/hour~50
It is preferable to set the temperature to about ℃/hour. (4) Quantity ratio The usage ratio of each component is the molar ratio per magnesium halide used, and the epoxy compound is 0.1 to 5, preferably 0.2 to 3, and the phosphorus compound is 0.1 to 1.5, preferably 0.2 to 1.0. Titanium halide is 0.5 to 100, preferably 1 to 15,
and organic acid ester (if used)
It is in the range of 0.05 to 0.5, preferably 0.1 to 0.4. (3) Precipitated solid Unlike the case of the prior art, the precipitated solid obtained in this way immediately becomes D/(Ti+
Mg) ratio is 0.5 or less (here, D is the sum of epoxy compounds, phosphorus compounds, and organic acid esters), and the Ti/Mg atomic ratio is 1/8 or less, which does not contain much Ti. is obtained. Considering the IR diagram of the precipitated solid,
The absorption caused by the epoxy ring, alone, in the Mg complex, and in the Ti complex, almost completely disappears, and instead, the absorption caused by the alkoxy group, which is thought to be Mg-OR or Ti-OR, appears at 1050 cm ^-1
found before and after. It is thought that this change corresponds to a decrease in the D/(Ti+Mg) ratio in the precipitated solid. In addition, as shown in Example 2 below, the generated alkoxy group was temporarily set to D
Even if it is added to the value of D/(Ti+Mg), the characteristic that the value of D/(Ti+Mg) is 0.5 or less is still maintained. When examining the X-ray diffraction image of the precipitated solid, 2θ = 15° (CuKα), which is usually noticeable in magnesium chloride.
The nearby peaks completely disappeared and became amorphous, suggesting that the magnesium halide is formed into a different type of complex by the electron donor (epoxy compound, phosphorus compound, and organic acid ester) and titanium compound. be exposed. (4) Treatment with component (B) (titanium tetrahalide) The solid precipitate obtained as described above, namely component (A), contains residual solvent and its reactants, and polymerization is good as it is. Do not give catalyst. The present invention solves this problem by allowing titanium tetrahalide to act on this precipitated solid. The titanium tetrahalide used in this case is
Titanium tetrachloride, tetrabromide or tetraiodide, which is the same or different from that used in the production of component (A).
Also in this case, titanium tetrachloride is preferred. The amount of titanium tetrahalide used is approximately 1 to 20, preferably 2 to 15, in molar ratio per magnesium halide. The contact between the precipitated solid (B) and the titanium tetrahalide can be carried out without a solvent or in an inert solvent as described above. The contact between the two is at 40-140°C, preferably 50-90°C,
at a temperature of 0.5 to 6 hours, preferably 1 to 6 hours.
Preferably, it is carried out under stirring for a period of about 3 hours. It is also a preferred embodiment to collect the precipitated solid after the treatment, wash it with a hydrocarbon or halohydrocarbon, and then perform the treatment with titanium tetrahalide one to several times. The precipitated solid treated with titanium tetrahalide is
The solid catalyst component of the present invention is preferably washed with an inert solvent as described above. (5) Polymerization of α-olefin The catalyst component of the present invention can be used in the polymerization of α-olefin in combination with an organometallic compound as a cocatalyst. (1) Cocatalyst An organoaluminum compound represented by the general formula AlR _a X _3-a is used. Here, R is hydrogen, a hydrocarbon residue having 1 to 20 carbon atoms, especially an alkyl group, an aralkyl group, or an aryl group, X is a halogen, especially chlorine or bromine, and a satisfies 0<a≦3. The number is within the range. Specifically, (a) trialkyl aluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, and tridecylaluminum, (b) diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquichloride, ethyl Alkyl aluminum halides such as aluminum dichloride, (c)
There are alkyl aluminum halides such as diisobutyl aluminum halide, and others. Among these, trialkyl aluminum is particularly preferred. The amount of the organoaluminum compound used is 0.01 to 200, preferably 0.03 to 100, in weight ratio to the solid catalyst component, but the range depends on the amount of the electron donating compound (details described later) used as necessary. It depends on the ratio. (2) Electron-donating organic compound As the electron-donating organic compound, a compound selected from alcohols, ethers, esters, ketones, and aldehydes is used. Among these compounds, organic acid esters, more preferably α,β-unsaturated carboxylic acids,
Particularly preferred are esters of monocarboxylic acids, especially esters with monohydric alcohols. "α, β
The definition of "unsaturated" includes aromatic unsaturation as well as ethylenically unsaturated. Examples of such esters include, for example, lower alkyl ( _C1 - _C12 ) benzoates, such as methyl and ethyl esters, lower alkyl (e.g., ethyl) p-toluate esters, lower alkyl (C1-C12) p-anisates, etc. For example, i-propyl) ester, lower alkyl methacrylate (e.g. methyl) ester, lower alkyl acrylate (e.g. ethyl ester), lower alkyl cinnamate (e.g. ethyl) ester, di-lower alkyl maleate (e.g. dimethyl) ester, etc. Particularly preferred are lower alkyl esters of aromatic carboxylic acids such as benzoic acid or p-toluic acid. (3) Olefin The olefin polymerized in the catalyst system of the present invention has the general formula R-CH=CH ₂ (where R is a hydrogen atom or a hydrocarbon residue having 1 to 10 carbon atoms, and may have a substituent).Specifically, examples include ethylene, propylene, butene-1, Penten
There are olefins such as 1,4-methyl-pentene-1. Preference is given to ethylene or propylene, particularly preferably propylene. It is also possible to use mixtures of α-olefins. For example, in the case of propylene polymerization, it is possible to copolymerize propylene with up to 20% by weight of other α-olefins (in particular ethylene). In addition, the above α
- Copolymerization with copolymerizable monomers other than olefins (eg, vinyl acetate, diolefins) can also be carried out. In any case, it goes without saying that the present invention is particularly effective in homopolymerization and copolymerization of α-olefins of propylene or higher (for example, copolymerization with ethylene) where stereoregularity is a problem. . (4) Polymerization The catalyst system of the present invention can be applied not only to ordinary slurry polymerization, but also to liquid-phase solvent-free polymerization or gas-phase polymerization, which uses substantially no solvent, as well as continuous polymerization and batch-type polymerization. It can be applied to both polymerization and prepolymerization methods. In the case of slurry polymerization, the solvent used is saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, cyclohexane, toluene, etc. alone or in mixtures. The polymerization temperature is from room temperature to about 200°C, preferably from 50°C to 150°C, and hydrogen can be added as a molecular weight regulator at this time. (6) Experimental Examples Example 1 (1) Preparation of solid catalyst component In a 300 ml four-necked flask purged with argon gas, 0.05 mol of MgCl ₂ , 75 ml of toluene, 0.1 mol of epichlorohydrin, and trin-phosphoric acid were placed in a 300 ml four-necked flask purged with argon gas.
0.03 mol of butyl was introduced and the temperature was raised to 50° C. with stirring to completely dissolve the solid. The solution was then cooled to -10 DEG C. and .45 mol of TiCl ₄ was added dropwise over 1 hour. The solution remained clear. In this state, 0.15 mol of ethyl benzoate was further added dropwise. This homogeneous solution was heated to 20°C over 1.5 hours. During this time, a solid precipitated from around 3°C. This slurry was further heated to 80°C and kept for 1 hour to complete the reaction. The temperature was returned to room temperature, and washing with toluene was repeated to obtain a precipitated solid. Then, 50 ml of toluene and 0.45 mol of TiCl ₄ were added, and the mixture was heated to 90° C. with stirring and maintained for 2 hours. After that, the supernatant was removed and the same operation was repeated once again. Finally, it was thoroughly washed with heptane to obtain a solid catalyst component. As a result of analysis, this solid catalyst component was found to be made of titanium.
3.85% by weight and 19.3% by weight magnesium. (2) Polymerization After replacing a stainless steel autoclave with an internal volume of 1 liter with propylene gas, add 500 ml of industrial heptane and 215 ml of triisobutyl aluminum.
mg, ethylaluminum sesquichloride 52
41.4 mg of methyl p-toluate, and 0.4 mg of the above solid catalyst component in terms of titanium atoms were introduced, and a propylene pressure of 1 Kg/cm ² G was added and the mixture was heated at room temperature for 30 mg.
Prepolymerize for 1 minute, then add 200 ml of hydrogen and raise the temperature to 70°C, and reduce the total propylene pressure to 9 kg/cm ² G.
Polymerization was carried out for 2 hours. The obtained polypropylene powder had extremely uniform particle size, with 4% having a differential particle size of 100 μm or less and 95% having particles between 100 and 500 μm. The polymerization characteristics are shown in Table-2. In addition, the polymerization conditions of Examples 2 to 19 are also the same. Example 2 The conditions for producing the solid catalyst component of Example 1 were repeated. However, ethyl benzoate was added dropwise before _TiCl4 . Table 1 shows the analysis results of the intermediate precipitated solid (A) and the final solid catalyst component thus obtained. In the IR diagram of the precipitated solid (A), there is a strong absorption near 1050 cm ^-1 that is thought to be caused by alkoxy groups, indicating that epichlorohydrin is somehow incorporated into the precipitated solid (A) after ring opening. It shows.

[Table] When the above composition is expressed as a ratio, the precipitated solid (A) appears to be TiMg _10.2 Cl _18.9 (EB) _1.5 (TBP) _0.2 .
However, EB is ethyl benzoate and TBP is butyl phosphate. The (EB+TBP)/(Ti+Mg) ratio is 0.15 (assuming that everything other than the analytical values are alkoxy groups due to ring opening of epichlorohydrin, the apparent composition is TiMg _10.2 Cl _18.9 (OR) _2.3 (EB) _1.5
(TBP) _0.2 , (OR+EB+TBP)/(Ti+
Mg) ratio is 0.36, and the requirement of the present invention that this ratio is smaller than 0.5 is complied with. ). Also,
The apparent composition of the catalyst is TiMg _8.8 Cl _20.2 (EB) _1.1
(TBP) is _0.1 , and (EB+TBP)/(Ti+Mg)
The ratio was 0.12. The results of polymerization using this solid catalyst component are shown in Table 2. Reference example 1 75ml of toluene in a 300ml flask,
0.05 mol of MgCl ₂ and 0.1 mol of epichlorohydrin were added, and the mixture was heated to 80° C. with stirring, but MgCl ₂ did not dissolve. Another 0.3 mol of epichlorohydrin was added and stirring was continued at 80°C for 3 hours, but still
_MgCl2 did not dissolve. When 0.1 mole of epichlorohydrin was added, the MgCl ₂ dissolved. 0.15 mol of ethyl benzoate was added to this solution, a precipitated solid was prepared in the same manner as in Example 2, and a solid catalyst component was further obtained. However, TlCl ₄ used for precipitation
was increased to 0.67 mol due to the increase in the amount of solubilizer. The results of polymerization using this solid catalyst component are also shown in Table 2, and it is clear that the activity, II, and polymer bulk density are both low, indicating that the epoxy compound alone does not produce good results. Examples 3 to 9 Following Example 2, the results of varying the amounts of epichlorohydrin and tributyl phosphate are shown in Table 2. Examples 10 to 18 Table 3 shows the results of using various epoxy compounds and phosphorus compounds in place of epichlorohydrin and butyl phosphate according to Example 2. Example 19 The method of Example 2 was repeated. However, a solution of MgCl ₂ to which ethyl benzoate had been added was heated to 40° C., and TiCl ₄ was added dropwise thereto over 2 hours. Precipitation of solid powder was observed simultaneously with the dropping. The resulting solid catalyst component contained 3.95% by weight of titanium. Propylene was polymerized using this solid catalyst component, and the polymerization activity was 17.2Kg/g.Solid catalyst component I.
Results were obtained of I.96.1%, MI2.3, and polymer bulk density 0.33.

[Table] ** Melt index

【table】 [Brief explanation of drawings]

FIG. 1 is a flowchart to help understand the technical content of the present invention regarding a Ziegler type catalyst.

Claims (1)

[Scope of Claims] 1. A solid catalyst component for α-olefin polymerization, characterized by comprising a contact product of (A) and (B) below. (A) A magnesium halide solution prepared by dissolving magnesium halide in a solvent system consisting of an organic epoxy compound and an organic phosphorus compound, and titanium tetrahalide, and optionally, precipitated from this solution after contacting with an organic acid ester, D/(Ti+
D represents the total number of moles of the above epoxy compound, organic phosphorus compound and organic acid ester, and Ti and Mg represent the number of moles of magnesium and titanium. ). (B) Titanium tetrahalide.