JPH0141164B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a method for producing a propylene polymer. Conventionally, obtaining a polymer with high bulk density in the polymerization of propylene has been strongly desired in the technical field because it is possible to increase the slurry concentration in the reactor and therefore increase production capacity. There is. In addition, increasing the yield of crystalline polymer, that is, improving the stereoregularity of the polymer, increases the basic unit of raw material propylene and reduces the amount of amorphous polymer dissolved in the diluent. This makes it possible to simplify processing steps such as removal of amorphous polymers, which is extremely advantageous industrially. In recent years, various methods have been proposed for polymerizing propylene with high catalytic efficiency using highly active catalysts. However, with these methods, it is difficult to obtain polymers with satisfactory bulk density and crystallinity in good yield, and therefore, improving this problem is of extremely important industrial significance. be. In line with this demand, a method has been proposed in which a catalyst system containing titanium trichloride and an organoaluminum compound is pretreated at a temperature lower than 60°C in the presence of propylene as a method to increase the bulk density and stereoregularity of the resulting polymer. (Refer to Japanese Patent Publication No. 49-14865). In this method, in the main polymerization after pretreatment, the bulk density and stereoregularity of the resulting polymer, which rapidly decrease as the polymerization temperature rises, are relatively gradually reduced in order to obtain high catalyst efficiency. However, it was difficult to say that a satisfactory effect could be obtained. In particular, the improvement effect was weak at a polymerization temperature of 60 to 70°C, which is realistic from an industrial point of view. In addition, in this method, it is essential that an appropriate amount of hydrogen be present in order to prevent the formation of molded articles from the produced polymer. However, controlling the appropriate amount of hydrogen is often difficult in practice. In other words, if the hydrogen content is too low, the molded product's hardness will increase.
If the amount is too large, the yield of the crystalline polymer will decrease, and even if a predetermined amount of hydrogen and propylene are charged, the hydrogen concentration will change due to propylene absorption. In addition, an inert solvent dispersion obtained from a δ-type titanium trichloride composition obtained by treating Ticl ₃ 1/3 Alcl ₃ or β-type titanium trichloride containing Alcl ₃ with a complexing agent and pulverizing it and an alkyl aluminum chloride. A method for activating a propylene polymerization catalyst has been proposed to slowly absorb propylene into
(See Publication No. 108693). However, with this method, it is not possible to increase the supply rate of propylene, and therefore an extremely long time is required for propylene absorption treatment. In view of the above background, the present inventors have completed the present invention through extensive research in order to solve the problems of the prior art. An object of the present invention is to provide a method for producing a propylene polymer having excellent catalytic efficiency, high bulk density and crystallinity, and from which a molded article with no buildup can be obtained. The gist of this is that solid titanium trichloride obtained by precipitating liquefied titanium trichloride in the presence of ether at a temperature below 150°C is mixed with an inert solvent and an organoaluminum compound, and this mixture is mixed with an inert solvent and an organoaluminum compound. Propylene is injected into the liquid phase of the reactor containing the reactor, substantially all of it is absorbed into the mixture, and the partial pressure of propylene in the gas phase of the reactor is maintained at 0.2 kg/cm ² or less. A method for producing a propylene polymer, which comprises slurry polymerizing propylene in the presence of an inert solvent or liquefied propylene using a catalyst containing solid titanium trichloride containing a propylene polymer and an organoaluminum compound. The present invention will be explained in detail below. First, a method for producing solid titanium trichloride, which is used in the present invention and is obtained by precipitating liquefied titanium trichloride in the presence of ether at a temperature of 150° C. or lower, will be described. This manufacturing method is disclosed in Japanese Patent Application No. 49-88476 (Japanese Unexamined Patent Publication No. 51-88
16297), Japanese Patent Application No. 1984-88477 (Japanese Patent Application No.
51-16298), Japanese Patent Application No. 1982-120100 (see Japanese Patent Application Laid-open No. 51-46598), Japanese Patent Application No. 1154 (Sho 51-76196), Japanese Patent Application No. 1983 −
No. 124049, Japanese Patent Application No. 16722 (1972)
(see Japanese Patent Application No. 1987-19552). To explain this specifically, the following two methods are usually used to obtain liquefied titanium trichloride (hereinafter referred to as "liquid titanium trichloride"). (A) A method using titanium tetrachloride as a starting material and reducing it with an organoaluminum compound in the presence of ether and, if necessary, a suitable hydrocarbon solvent. (B) A method in which solid titanium trichloride is used as a starting material and treated with ether in the presence of a hydrocarbon solvent if necessary. First, to explain the method (A) above, various ethers are used as the ether compound in this method, but ether compounds that are soluble in hydrocarbon solvents are particularly preferred.For example, the following general formula (1), That is, R ¹ OR ² ...(1) (wherein R ¹ and R ² are the same or different alkyl groups, aralkyl groups, alkenyl groups, aryl groups,
Indicates an alkaryl group. ) are mentioned. Specific examples include di-n-amyl ether, di-n-butyl ether, di-n-propyl ether, di-n-hexyl ether, di-n-heptyl ether, di-n-
-octyl ether, di-n-decyl ether,
Di-n-dodecyl ether, di-n-tridecyl ether, n-amyl-n-butyl ether, n
-amyl isobutyl ether, n-amyl ethyl ether, n-butyl-n-propyl ether,
n-butyl isoamyl ether, ethyl-n-hexyl ether, n-propyl-n-hexyl ether, n-butyl-n-octyl ether, n
-Dialkyl ethers such as hexyl-n-octyl ether; bis(1-butenyl) ether,
Dialkenyl ethers such as bis(1-octenyl) ether, bis(1-decynyl) ether, and 1-octenyl-9-decynyl ether; dialkyl ethers such as bis(benzyl) ether; bis(tolyl) ether; Bis(xylyl)
Dialkaryl ethers such as ether, bis(ethyl phenyl) ether, tolyl xylyl ether; n-propyl-1-butenyl ether, n
- Alkyl alkenyl ethers such as octyl-1-decynyl ether and n-decyl-1-decynyl ether; n-octyl-benzyl ether,
Alkyl aralkyl ethers such as n-decyl-benzyl ether; alkylaryl ethers or alkyl alkyl ethers such as n-octyl phenyl ether, n-octyl tolyl ether, n-decyl tolyl ether; 1-octenyl benzyl ether Aralkyl alkenyl ethers or alkaline alkenyl ethers such as 1-octenyl phenyl ether, 1-octenyl tolyl ether; aralkyl such as benzyl phenyl ether, benzyl tolyl ether Ali
and aralkyl alkali ethers. Especially preferred as the ether is an ether in which R ¹ and R ² in the above formula (1) are linear hydrocarbon residues such as an alkyl group or an alkenyl group. In addition, the hydrocarbon solvent used as necessary in the above method (A) is appropriately selected depending on the type of ether used, but specifically, n-pentane, n-hexane, n-heptane, n- - Saturated aliphatic hydrocarbons such as octane, n-dodecane, and liquid paraffin; Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; Aromatics such as benzene, toluene, xylene, 1,2,4-trimethylbenzene, and ethylbenzene It is appropriately selected from hydrocarbons and the like. For example, when using an ether in which at least one of R ¹ and R ² in formula (1) is an alkyl group or alkenyl group having 5 or less carbon atoms, the hydrocarbon solvent is preferably an aromatic hydrocarbon, Next, it is selected from alicyclic hydrocarbons, and when using an ether in which R ¹ and R ² are an alkyl group or an alkenyl group having 6 or more carbon atoms, it is selected from saturated aliphatic hydrocarbons. is preferable. Next, the organoaluminum compound used for the reduction treatment in method (A) above has the general formula AlR ³ nX _3-o ...(2) (wherein R ³ represents a hydrocarbon group having 1 to 20 carbon atoms. , n is a number from 1 to ³ , and X represents a halogen atom. Examples include ethylaluminum sesquichloride, diethylaluminum chloride, trialkylaluminium, and the like. The amount of the organoaluminum compound used in the above-mentioned reduction treatment of titanium tetrachloride is such that the molar ratio of titanium tetrachloride to the organoaluminum compound is R ³ (carbonized) of titanium and the organoaluminum compound represented by the general formula (2). (hydrogen group, preferably alkyl group)
Expressed as a molar ratio, the molar ratio is within the range of 1:0.1 to 50, preferably 1:0.3 to 10. The amount of ether used is such that the molar ratio of ether to titanium tetrachloride is 1:
The ratio is in the range of 0.05 to 5, preferably 1:0.25 to 25. This reduction treatment can be carried out by various methods, for example, the following method. (a) A homogeneous liquid material consisting of titanium tetrachloride and ether is mixed with an organoaluminum compound. (b) Mix titanium tetrachloride with a homogeneous liquid consisting of an organoaluminum compound and ether. (c) Mixing a homogeneous liquid substance consisting of titanium tetrachloride and ether with a homogeneous liquid substance consisting of organoaluminum and ether. (d) Titanium tetrachloride, ether, and organoaluminum compound are mixed in any order at a temperature at which no reduction reaction occurs, for example, at -30°C or lower, and the mixture is heated to a predetermined temperature. Titanium tetrachloride used in these methods,
The ether and the organoaluminum compound may be used as they are or diluted with a hydrocarbon solvent as appropriate. Therefore, it is preferable to use the organoaluminum compound diluted with a hydrocarbon solvent. When titanium tetrachloride is reduced with an organoaluminum compound in the presence of ether as described above, a liquid is obtained, which is titanium trichloride.
A homogeneous solution or mixture of ethers, soluble in hydrocarbons, having a brown or greenish brown color. Next, we will explain the method (B) above, that is, a method for obtaining a liquid titanium trichloride by using solid titanium trichloride as a starting material and treating it with ether in the presence of an appropriate hydrocarbon solvent as necessary. do. Solid titanium trichloride is, for example, titanium trichloride obtained by reducing titanium tetrachloride with hydrogen gas, aluminum or an aluminum organometallic compound, or the solid titanium trichloride obtained in this way is further ground in a ball mill, or Those that have been subjected to heat treatment, and further those that have been purified from the solid titanium trichloride obtained as described above to remove impurities contained therein, are used. The ether used to obtain the titanium trichloride liquid and the hydrocarbon solvent present if necessary are the same as those explained for the method (A) above. The amount of ether used in this method (B) is such that the molar ratio of ether to titanium trichloride is 1 or more, preferably within the range of 1 to 5. The treatment of solid titanium trichloride with ether can be carried out by mixing the two in any manner. This treatment is usually preferably carried out in the presence of a hydrocarbon solvent appropriately selected depending on the type of ether, as explained in the method (A) above. By this method (B), a liquid material equivalent to the liquid material obtained by the above-mentioned method (A) can be obtained. In this way, a titanium trichloride liquid can be advantageously obtained by the above method (A) or (B). Next, in order to obtain fine particulate titanium trichloride from this liquid material, this liquid material may be heated as is or after adding a hydrocarbon solvent similar to the above as necessary, at a temperature of 150°C or lower, usually 20 to 150°C.
℃, preferably 40~120℃, more preferably 60~
If the temperature is raised to within the range of 100°C and maintained at the same temperature for some time, fine particulate titanium trichloride will precipitate, which can be fractionated. In the present invention, the solid titanium trichloride obtained as described above is mixed with an inert solvent and an organoaluminum compound. The organoaluminum compound used in this case has the general formula AlR ⁴ mX _3-n ... (4) (wherein R ⁴ is the same or different number of carbon atoms
20 saturated or unsaturated hydrocarbon groups, X is a halogen atom, m is a number of 1.5, 2 or 3; ) Organoaluminum compounds represented by: Specific examples include trimethylaluminum, triethylaluminum, triisobutylaluminum,
Trialkylaluminums such as trihexylaluminum; alkylaluminum halides such as dimethylaluminum chloride, diethylaluminium chloride, diethylaluminium bromide, ethylaluminum sesquichloride; mixtures of aluminum halides and trialkylaluminum; indenyl diethyl Aluminum, isodenyldipropylaluminum, indenylisobutylaluminum, etc. are also used. Among these, preferred is dialkyl aluminum halide, and particularly preferred is diethyl aluminum chloride. As the inert solvent to be mixed with these organoaluminum compounds, inert hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons used in ordinary olefin polymerization are used. Among these, normal hexane and normal heptane are preferred. Although the amount of solid titanium trichloride dispersed in the inert solvent is not critical, a certain concentration range is essential. Usually, it is preferable that titanium trichloride is in the range of 1 to 50 g, preferably 5 to 30 g in the inert solvent 1. If this is too low, the polymer obtained when propylene is polymerized using titanium trichloride as a catalyst component Increased stickiness in molded products. In this process, it is industrially advantageous to increase the throughput of solid titanium trichloride, so it is preferable to select a concentration as high as possible within a range that allows normal stirring. The amount of organoaluminum compound used is usually 0.1 to 2 molar ratio, preferably 0.1 to 2 molar ratio to solid titanium trichloride.
The molar ratio is 0.5-1.0. The temperature at which propylene is blown into the mixture of solid titanium trichloride, an inert solvent, and an organoaluminum compound is usually in the range of 0 to 70°C, preferably 35 to 60°C, and more preferably 50 to 60°C. If this treatment temperature is too high, when propylene is polymerized with a catalyst containing solid titanium trichloride containing a propylene polymer, the bulk density of the polymer obtained in the main polymerization will be improved and the yield of crystalline polymer will be improved. becomes insufficient. Furthermore, if the treatment temperature is too low, the temperature difference between the treatment tank and the cooling water will be small, which will be industrially disadvantageous in terms of heat removal. In the present invention, propylene is introduced into the liquid phase of a reactor containing the above-mentioned mixture of solid titanium trichloride, an inert solvent, and an organoaluminum compound. 10Kg, preferably 1-5Kg. If the introduction rate is too high, it becomes difficult to control the reaction temperature, and if it is too low, the treatment time becomes longer, which is not preferred from an industrial perspective. Also, when introducing propylene, the most important thing is to keep the propylene partial pressure in the gas phase of the reactor at 0.2 Kg/cm ² or less, preferably at almost zero. If the temperature is too high, not only will the objectives of the present invention of improving the bulk density and crystalline polymer yield of the polymer obtained by main polymerization of propylene not be achieved sufficiently, but also the solidity of molded products made from this polymer will deteriorate. To increase. The propylene partial pressure is determined by the balance between the propylene introduction rate and the propylene absorption rate, and can be fully controlled as long as the above-mentioned suitable solid titanium trichloride is treated under suitable conditions. Although the propylene partial pressure may be monitored by analyzing the gas phase of the reactor, it is sufficient to monitor the pressure gauge attached to the gas phase. The above contact treatment of solid titanium trichloride and propylene produces a propylene polymer.
Preferably, 50 g of propylene polymer is produced. In the present invention, hydrogen does not necessarily need to be present in the above-mentioned propylene contact treatment, and even if hydrogen is not used, no fixation will occur in the molded product from the polymer produced by main polymerization. on the other hand,
Addition of hydrogen may impair the effect of improving the bulk density of the polymer and the yield of crystalline polymer. Further, in the present invention, a small amount of other α-olefins such as ethylene, butene-1, 4-methylpentene-1, etc. may be used in combination with the introduced propylene. The propylene polymer-containing solid titanium trichloride produced by the above treatment is separated from the liquid phase containing unreacted substances, inert solvents, etc. by ordinary separation means such as decantation, filtration, and centrifugation. However, add more solvent and wash several times. As this solvent, it is advantageous to use the inert hydrocarbon solvent used in the above-mentioned propylene contact treatment. It is desirable to carry out the washing a sufficient number of times to remove soluble components, but if it is too many, the amount of detergent used becomes large, which is industrially disadvantageous. As described above, the propylene polymer-containing solid titanium trichloride used in the method of the present invention is obtained, and this material is used for propylene polymerization (main polymerization) by adding an organoaluminum compound as a catalyst.
Serve. As the organoaluminum compound added in the main polymerization, those mentioned in the above-mentioned pretreatment step, ie, the compound represented by the above general formula (2), can be used.
Generally, it is preferable to use the same organoaluminum compound as used in the pretreatment step, but a different organoaluminum compound may be used depending on the case. For example, a preferred example is to use a dialkyl aluminum monohalide in the pretreatment step and to use trialkyl aluminum in the main polymerization. The amount of the organoaluminum compound used is usually 0.1 to 100 times the amount of the titanium compound in the propylene polymer-containing titanium trichloride, preferably 2 to 10 times the amount by mole.
It is double the molar amount. be. FIG. 1 of the accompanying drawings shows a flowchart relating to the preparation process of a catalyst used in the method for producing a propylene polymer of the present invention. In the propylene polymerization method of the present invention, a sufficiently high yield of crystalline polymer can be obtained even with the catalyst consisting of the propylene polymer-containing solid titanium trichloride and an organoaluminum compound. A third component can also be used in the catalyst composition to improve the polymerization. In the main polymerization of propylene, the propylene polymer-containing solid titanium trichloride and the organoaluminum compound (with a third component added if necessary) are simply mixed and used for polymerization, but the mixing method may be arbitrary. . The polymerization method in the main polymerization can be carried out by known slurry polymerization. These polymerization methods may be continuous or batchwise, and the reaction conditions are 1 to 100 atmospheres, preferably 5 to 30 atmospheres, and 50 to 90°C, preferably 60 to 70°C. In slurry polymerization, the same solvent as the inert solvent used in the titanium trichloride pretreatment step described above is used as the polymerization medium, specifically hexane,
Examples include hydrocarbons such as heptane, cyclohexane, benzene, toluene, pentane, butane, and propane. It is also possible to appropriately add known molecular weight regulators such as hydrogen and diethylzinc to the polymerization reaction using propylene itself as a medium control method. It is. Although propylene alone may be polymerized in the main polymerization of the present invention, propylene and other α-olefins may be used in combination. Other α-olefins are ethylene, butene-1, 4-methylpentene-1, etc., as in the pretreatment step, and the amount thereof is small enough that the product does not lose its properties as a propylene polymer. For example, it is 5% by weight or less based on propylene. When propylene is polymerized according to the method of the present invention using solid titanium trichloride containing a propylene polymer as described above as a catalyst component, the bulk density of the resulting propylene polymer is high and the stereoregularity is significantly improved. Ru. Bulk density in preferred cases
0.50g/cc, boiling heptane raffinate of 98% or more is easily achieved. The industrial significance brought about by the present invention is as follows. First, the present invention greatly increases polymer production capacity. This is due to the improved bulk density and stereoregularity of the polymer achieved by the present invention. That is, since the polymer obtained by the polymerization method of the present invention has a high bulk density, even if it is suspended in hexane and the slurry concentration is 50%, it still shows good fluidity and high productivity can be obtained. In addition, the production of less amorphous polymer prevents adverse effects such as increased viscosity of the polymerization system and adhesion to piping, etc., and improves productivity from the standpoint of operational stability. Can be done. Second, the polymer obtained by the method of the present invention has high stereoregularity, that is, the production of industrially worthless amorphous polymer is extremely small, so the processing equipment for amorphous polymer can be used extensively. It can be simplified. Considering that amorphous polymers are not only industrially worthless, but also require enormous amounts of equipment to process,
It can be said that the economic significance of simplifying the processing equipment is very large. Thirdly, the polymer obtained by the method of the present invention has excellent mechanical properties despite having extremely high stereoregularity. For propylene polymers obtained by conventional polymerization methods, when the boiling heptane raffinate of the product exceeds 98%, the yield strength of the pressed pieces increases, but the impact strength decreases, resulting in what is called hard and brittle properties. is normal. In contrast, according to the method of the present invention, the polymer has a boiling heptane raffinate of 98
%, no decrease in impact strength is observed. Although the reason for this is not clear, it is thought that the propylene polymer produced by the method of the present invention maintains a heteroblock structure even though the boiling heptane raffinate is significantly increased. Therefore, it can be said that the properties of such polymers obtained by the method of the present invention are completely unexpected.
This means that it is possible to increase the yield of stereoregular polymers, which achieves the desired results of improved productivity and simplified equipment, without the limitation of deterioration of mechanical properties as described above, and is extremely useful in industrial applications. It can be said to have great significance. Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not restricted by the following examples unless the gist of the invention is exceeded. In the following examples and comparative examples, K ₀ (polymerization activity) is the total amount (g) of propylene polymer produced per hour, per 1 kg/cm ² of propylene pressure, per 1 g of titanium trichloride catalyst component. II (isotactic index) is the residual amount (% by weight) after extraction with boiling n-heptane for 6 hours in an improved Soxhlet extractor. IIo is II of the total propylene polymer produced and represents the yield of crystalline polymer in the total product. ρB is the bulk density (unit: g/cc) and was measured according to JIS-6721. MFI is a melt flow index and was measured according to ASTM D-1238, and tensile impact strength was measured according to ASTM-D1822. Examples 1 to 5 (A) Preparation of solid titanium trichloride: At room temperature, 5.5 liters of purified n-hexane was placed in a 10 capacity autoclave that was sufficiently purged with nitrogen.
While stirring, 630 g of n-octyl ether, 630 g of titanium tetrachloride, and diethylaluminum chloride.
132 g was added to obtain a brown homogeneous solution. then
Gradually raise the temperature to 95℃. When the temperature exceeded 50°C, purple fine particulate solid precipitation was observed. After being held at 95° C. for about 1 hour, a granular purple solid was separated and washed with n-hexane to yield 410 g of solid titanium trichloride. (b) Production of propylene polymer-containing titanium trichloride (pretreatment step): Put 5 purified n-hexane into a 10 autoclave that was sufficiently purged with nitrogen, and add 39 g of diethylaluminium chloride and the solid titanium trichloride obtained in (A) above. 100g of Ticl ₃ was prepared. The temperature was raised to the temperature shown in Table 1 below, and propylene gas was blown into the liquid phase of the mixture at the time and rate shown in Table 1 to carry out polymerization. During this period, the fluctuation of the gas phase pressure gauge was 0.05.
Kg/cm ² or less, and propylene was not detected in gas phase gas analysis (detection sensitivity 1%). The solid components were then allowed to settle, and the supernatant liquid was removed by decantation and washed several times with n-hexane to obtain solid titanium trichloride containing a propylene polymer. (C) Polymerization of propylene: 750 ml of purified n-hexane and diethylaluminium monochloride in a sufficiently dried SUS304 autoclave (inner volume 2) purged with nitrogen.
156 mg and 40 mg of the propylene polymer-containing solid titanium trichloride obtained in (B) above in terms of Ticl ₃ , and the third
As components, the compounds shown in Table 1 were charged in an amount of 0.1 mole based on Ticl ₃ , and hydrogen was further charged at 0.5 kg/cm ² . Measure 1: Raise the temperature to the temperature shown in Table with stirring, supply propylene to a total pressure of 13.5 kg/cm ² ,
Polymerization was carried out for 5 hours while maintaining a constant pressure. Immediately after the completion of the polymerization reaction, unreacted monomer gas is purged, and then a portion of the contents of the autoclave is collected to obtain total II, and the remaining polymer is treated with n-hexane to extract and remove the soluble polymer. The mixture was dried to obtain a white powdery propylene polymer. Table 1 shows the bulk density of the obtained polymer. In addition, 0.2% by weight of 2,6-di-t-butyl-P-methylphenol (BHT) was added to this as an antioxidant based on the propylene polymer, and the mixture was pelletized using a pelletizer with a diameter of 20 mm, and then pressed into a press sheet. was made and its impact strength was measured. The results are shown in Table 1. Comparative Examples 1 to 3 The solid titanium trichloride obtained in (A) of Examples 1 to 5 was treated with an organoaluminum compound and the titanium trichloride listed in Table 1 without performing the pretreatment described in (B) of the same example. The three components were added, and propylene was polymerized in the same manner as described in section (c) of the same example. The result is the first
Shown in the table. Judging from the results in Table 1, even if solid titanium trichloride obtained by precipitating titanium trichloride liquefied in the presence of ether at a temperature below 150°C is used, if pretreatment with propylene is not performed, ( Compared to Comparative Examples 1 and 2) and Examples 1 and 2, the yield of the crystalline polymer, that is, IIo, was lower, the bulk density of the polymer powder was also lower, and the impact strength of the molded product from the obtained polymer was lower. It is clear that it is inferior. In Comparative Example 3, hydrogen was added at 0.2 Kg/cm ² , but in this case it was shown that the yield and bulk density of the crystalline polymer were inferior to the case without hydrogen (Example 3). Ta.

【table】

[Table] Examples 6-7 17 n-hexane and 132 g of diethylaluminium chloride in 20 reactors sufficiently purged with nitrogen
and about 400 g of solid titanium trichloride (330 g as titanium trichloride) obtained in the same manner as described in (a) of Example 1.
Prepare. The temperature is then raised to the temperature listed in Table 2, and propylene gas is blown into the liquid phase at the flow rate and time listed in Table 2. During this period, the fluctuation of the pressure gauge in the gas phase was 0.05.
It was less than Kg/ ^cm2 . Next, the solid component was allowed to settle, and the supernatant liquid was removed by decanting and washed several times with n-hexane to obtain a propylene polymer-containing solid titanium trichloride. Next, the propylene polymer-containing solid titanium trichloride, diethylaluminium chloride, n-hexane, propylene, hydrogen, and the third component of the catalyst shown in Table 2 were continuously fed to each of the 400 reactors, and the second Total pressure at listed temperature
Polymerization was carried out continuously at 13.5 Kg/cm ² (gauge pressure) and an average residence time of 5 hours. Table 2 shows the polymerization activity (ko) determined from the polymer production rate and the supply rate of solid titanium trichloride containing propylene polymer. The polymer slurry was purged of unreacted propylene in a degassing tank, then isopropanol was added so that the isopropanol concentration in the inert solvent was 5%, and after continuous treatment at 70°C, it was dehydrated using a centrifuge. The combined cake was separated into liquids. The product propylene polymer was taken out as a powder from the cake through a drying process, and the amorphous polymer dissolved in the solvent was concentrated and separated from the liquid. Table 2 shows the ratio of the amorphous polymer thus obtained to the total polymer as the amorphous polymer production rate. 0.2% BHT was added as an antioxidant to the product powder obtained as described above, which was pelletized at 250°C using a pelletizer with an inner diameter of 40 mm, and then formed into a 30 μm water-cooled inflation film. This film was cut into a size of 150 cm x 10 cm, and the fish eyes of 0.1 mm or more were counted, and the results shown in Table 2 were obtained. Comparative Example 4 Solid titanium trichloride obtained as described in (a) of Example 1 was treated with hydrogen at a partial pressure of 0.2 Kg/cm ² before introducing propylene gas in the pretreatment step of Example 6. Except for the addition, the other processes were the same as in Example 6, and the subsequent continuous polymerization of propylene, fractionation of propylene polymer powder, and film forming were also carried out in the same manner as described in Example 6. The results are shown in Table 2. As shown in this table, when hydrogen is used in the pretreatment step to produce solid titanium trichloride containing propylene polymer, the production rate of amorphous polymer increases compared to the results of Example 6, and the product polymer The bulk density of Comparative Example 5 Solid titanium trichloride obtained in the same manner as described in (a) of Example 1 was treated in the same manner as in Example 7 except for the following points to obtain titanium trichloride containing a propylene polymer. That is, in the pretreatment step of Example 7, the partial pressure of the propylene gas in the gas phase is kept high, that is, 0.4 Kg/cm ² . Continuous propylene polymerization and film forming following this treatment were carried out in the same manner as in Example 7. The results are shown in Table 2. As can be seen from this table, the number of fixing eyes in the 30μ water-cooled film was significantly greater in this comparative example. Example 8 The solid titanium trichloride obtained as described in Example 1 (a) was pretreated in the same manner as in Example 6, with a propylene-ethylene mixture containing 3% ethylene instead of propylene gas. Treated with gas. A polymerization catalyst was prepared using the obtained propylene-ethylene copolymer-containing solid titanium trichloride, and during continuous propylene polymerization at a polymerization temperature of 60°C, the ethylene unit of the product polymer was adjusted to 4% by weight. The operation was carried out in exactly the same manner as in Example 6, except that ethylene was continuously supplied. The second result is
Shown in the table. Comparative Example 6 Polymerization of propylene-ethylene was carried out in exactly the same manner as in Example 8, except that the solid titanium trichloride obtained as described in (a) of Example 1 was used for continuous polymerization without pretreatment. I did this. The second result is
Shown in the table. The results of Example 8 and Comparative Example 6 show that the treatment of the present invention is extremely effective in improving the yield of crystalline polymer and bulk density of product powder even in random copolymerization.

【table】

[Table] In Table 2, CRE in *1 is an abbreviation for ethyl crotonate, other abbreviations are the same as in Table 1, and the catalyst in *2 is the feed rate of solid titanium trichloride containing propylene polymer. And that number is
This is a Ticl ₃ equivalent value. Examples 9 to 11 Purified normal hexane 5 was placed in an autoclave sufficiently purged with nitrogen, and 39 g of diethylaluminum monochloride and the electron-donating compound shown in Table 3 below were added in the amount shown in the same table,
Solid titanium trichloride obtained in Example 195 as Ticl ₃
I prepared 100g. The temperature was raised to the temperature shown in Table 3, and propylene gas was blown into the liquid phase of the autoclave at the time and rate shown in Table 3 to carry out polymerization. During this period, the fluctuation in the gas phase pressure gauge was less than 0.05 Kg/ ^cm2 , and propylene was not detected from the analysis of the gas phase (detection sensitivity: 1%).Next, the solid components were left to settle, and the supernatant liquid was collected. It was removed by decantation and washed several times with n-hexane to obtain solid titanium trichloride containing a propylene polymer. Next, polymerization was carried out in the same manner as in Examples 1 to 5(c) using an autoclave with an internal volume of 2, and the results shown in Table 3 were obtained. Moreover, using the obtained polymer, Examples 1 to 5 were prepared.
When a press sheet was molded by the method described in (c) and the tensile impact strength was measured, the results shown in Table 3 were obtained. All symbols in the table have the same meaning as those listed in Table 1.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a flowchart showing the steps for preparing a catalyst used in the production method of the present invention.

Claims (1)

[Claims] 1. Solid titanium trichloride obtained by precipitating liquefied titanium trichloride in the presence of ether at a temperature of 150°C or lower is mixed with an inert solvent and an organoaluminum compound, and this mixture is mixed with an inert solvent and an organoaluminum compound. Obtained by blowing propylene into the liquid phase of a reactor containing it, absorbing substantially the entire amount into the mixture, and maintaining the partial pressure of propylene in the gas phase of the reactor at 0.2 kg/cm ² or less. A method for producing a propylene polymer, which comprises slurry polymerizing propylene in the presence of an inert solvent or liquefied propylene using a catalyst containing a propylene polymer-containing solid titanium trichloride and an organoaluminium compound. 2. Production of a propylene polymer according to claim 1, wherein the propylene is polymerized using a catalyst containing a propylene polymer-containing solid titanium trichloride and an organoaluminum compound, and the propylene contains a small amount of other α-olefins. Law.