JPS6150086B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a propylene-ethylene block copolymer. More particularly, the present invention relates to a method for producing propylene-ethylene block copolymers with improved properties substantially without post-treatment using a highly active composite catalyst system. Crystalline polyolefins have been produced industrially since the invention of stereoregular catalysts by Ziegler and Natsuta et al. In particular, crystalline polypropylene
It is attracting attention as a general-purpose resin with excellent rigidity and heat resistance. However, crystalline polypropylene has the disadvantage of being brittle at low temperatures, so it is difficult to use in applications that require impact resistance at low temperatures. In order to overcome this drawback, various studies have been carried out in the past, and many improved methods have already been proposed, but among them, as a particularly industrially useful method,
A method of block copolymerizing propylene with other olefins, especially ethylene, is known. Namely, Special Public Official Publication 14834-14834, Special Public Official Publication 39-1483-
1836, as proposed in the Special Publication No. 39-15535, etc.
In the presence of a composite catalyst, in an inert solvent, propylene is first added to polymerize a crystalline propylene homopolymer block, and then ethylene or ethylene and propylene are added to form a statistical copolymer of ethylene-propylene. As proposed in Japanese Patent Publications No. 44-20621, No. 49-24593, No. 48-25781, etc., statistical copolymerization of ethylene-propylene in the block copolymer is proposed. A method in which a polymer block is further divided into two stages for polymerization is known and is widely practiced industrially. However, in such a method, after the completion of polymerization, the catalyst is decomposed, or the catalyst residue is extracted, and then the polymer particles are separated from the inert solvent, and further dried. Obtain a product polymer. On the other hand, industrially, separating the inert solvent usually involves a very complicated process of separating, purifying, and reusing the low-molecular-weight, low-crystalline polymer and catalyst residue dissolved in the inert solvent. Requires. In order to solve this problem,
13049, JP 47-26113, JP 49-120986, JP 51-135987, JP 52-3684, in the first step, in liquefied propylene in the absence of an inert solvent. A block copolymerization method has been proposed in which propylene is homopolymerized and then, in a second step, ethylene and propylene are statistically copolymerized in liquefied propylene or in a gas phase. In these methods, since substantially no inert solvent is used, the solvent purification step is omitted, and furthermore, the drying of the polymer can also be omitted or greatly simplified. Furthermore, if the steps of decomposing the catalyst contained in the polymer and removing the catalyst residue can be omitted or greatly simplified, the above-mentioned problems can be solved. However, in this method, a conventional catalyst system consisting of titanium trichloride obtained by reducing titanium tetrachloride with metallic aluminum or hydrogen, or a eutectic of titanium trichloride and aluminum chloride, and an organoaluminium, is used. In this case, since the amount of produced polymer per solid titanium trichloride catalyst is small, a large amount of catalyst residue remains in the obtained polymer particles. When the resulting polymer particles are made into molded products, they are colored yellow and their commercial value is significantly reduced. Further, polymer particles are usually melt-kneaded, pelletized, and then melted and molded using various molding machines, but the polymer deteriorates significantly during the melting process and its mechanical properties are impaired. In addition, deterioration due to ultraviolet rays is significant, making it difficult to use the molded product for a long period of time. Therefore, in such a method, in order to solve these problems, it is necessary to carry out post-treatments such as extraction of catalyst residues in the same way as in the case of polymerization in an inert solvent.
It still requires a lot of effort to manufacture. Furthermore, the solubility of low molecular weight, low crystallinity polymers is
Since the inert solvent normally used is larger than the liquefied monomer, when carrying out propylene-ethylene block copolymerization in the absence of an inert solvent,
The proportion of the low molecular weight, low crystalline polymer contained in the polymer particles is significantly higher than when polymerized in an inert solvent. Therefore, when known catalysts are used, the rigidity and heat resistance, which are characteristics of polypropylene, are impaired, making it difficult to use molded products in fields that require such physical properties. In addition, the characteristics of polymer particles include a large amount of low-molecular-weight, low-crystalline polymers present on the particle surface, which increases the adhesion between the particles, causing polymer agglomeration and weight buildup on the inner wall of the polymerization tank. Decrease in heat transfer efficiency due to coalesce adhesion,
Furthermore, there is the problem that clogging occurs frequently in piping, powder hoppers, and silos during the transfer of polymer slurry or polymer powder.
It is necessary to use a catalyst system that has a low molecular weight and produces a small amount of low-crystalline polymer as a by-product, that is, a catalyst system that has high stereoregularity. However, in the above-mentioned known catalyst system,
Both polymerization activity and stereoregularity are insufficient to substantially omit post-treatment, and although many studies have been conducted in the past, there are few that satisfy these requirements. As a result of intensive studies, the present inventors have overcome this problem and have succeeded in producing a propylene-ethylene block copolymer having improved properties in a stable manner without substantially post-treatment. A method was discovered, leading to the present invention. That is, in the first step, the present invention initiates polymerization by adding propylene alone or a small amount of ethylene under conditions in which propylene is present in liquid form in the substantial absence of an inert solvent. (A) When continuing the polymerization in liquefied propylene or in the gas phase, and subsequently performing statistical copolymerization of propylene and ethylene in liquefied propylene or in the gas phase in the second and subsequent stages, (A) Titanium tetrachloride is reduced with an organoaluminum compound, and further activated titanium trichloride solid catalyst and (B) general formula RlAlY ₃ -l (R is a linear alkyl group or alkoxy group having 1 to 8 carbon atoms) Y represents a halogen, hydrogen, or an alkoxy group; l is a number represented by 2≦l≦3; or further, (C) a stereoregularity improver; and The present invention relates to a method for producing a propylene-ethylene block copolymer, characterized in that the total polymerization amount per titanium trichloride solid catalyst is 8,000 g/g or more using a catalyst system comprising the following. In the present invention, the titanium trichloride solid catalyst used as the catalyst component (A), which is obtained by reducing titanium tetrachloride with an organoaluminum compound and further activating it, is produced, for example, by the method shown below. (1) Titanium tetrachloride is reduced with an organoaluminum compound represented by the general formula R'nA'lX' ₃ -n, and the resulting reduction product is further reduced to 50% in the presence or absence of an inert solvent. Titanium trichloride solid catalyst obtained by heat-treating at a temperature of ~120°C and reacting the obtained heat-treated solid with a mixture of a halogen compound and an ether compound (2) Titanium tetrachloride is formed by the general formula R' reduction with an organoaluminium compound represented by nAlX′ ₃ −n, and treating the obtained reduction product with an ether compound,
Titanium trichloride obtained by subsequently reacting the ether treated solid thus treated with titanium tetrachloride, or further reacting said titanium trichloride with a mixture of a halogen compound and an ether compound. Titanium chloride solid catalyst (3) Titanium tetrachloride is reduced with organoaluminium represented by R'nAlX' ₃ -n, the resulting reduction product is reacted with an ether compound, and the ether-treated solid prepared in this way is then reacted with an ether compound. General formula R″pAlX ₃
- Titanium trichloride solid catalyst obtained by reacting with an aluminum compound represented by p and then reacting with a mixture of a halogen compound and an ether compound In the present invention, the above-mentioned items (1), (2) and ( The titanium trichloride solid catalyst used as the catalyst component (A) shown in section 3) is disclosed in Japanese Patent Application Laid-Open No. 47-34478 and Japanese Patent Application No. 1986-
108276, patent application No. 51-127705, etc. The method of the present invention will be explained in more detail. In the above items (1), (2) and (3), the general formula R'nAlX' ₃ -n (R' is a linear alkyl group having 1 to 18 carbon atoms) is used to produce the reduction product. or represents a branched alkyl group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group. Examples of organoaluminum compounds include methylaluminum dichloride, ethylaluminum dichloride, n-propylaluminum dichloride, ethylaluminum sesquichloride, dimethylaluminum chloride, diethylaluminium chloride, di-n-propylaluminum chloride, trimethylaluminum, triethylaluminum, tri-isobutyl Examples include aluminum, ethyldicyclohexylaluminum, triphenylaluminum, diethylaluminum hydride, di-sobutylaluminum hydride, diethylaluminum bromide, diethylaluminium iodide, and the like. Among these, diethylaluminum chloride and ethylene aluminum sesquichloride are particularly preferred. In addition, in the above items (1) and (3), the ether compound used when the reduction product and the ether compound are reacted has the general formula R ₁ -O-R ₂ (R ₁ and R ₂
represents a linear alkyl group or a branched alkyl group having 1 to 8 carbon atoms, and R ₁ and R ₂ may be the same group or different groups. ) is a compound represented by in particular,
Diethyl ether, di-n-propylene ether, di-isopropyl ether, di-n-butyl ether, di-isoamyl ether, di-neopentyl ether, di-n-hexyl ether, methyl-n-butyl ether, methyl-isoamyl ether, Examples include compounds such as ethyl-isobutyl ether. Among these, di-n-butyl ether and di-isoamyl ether give particularly preferable results. In addition, in the above item (3), the general formula R″pAlX ₃ −p (R″ is a linear alkyl group having 1 to 18 carbon atoms, a branched alkyl group, or an alicyclic Represents a hydrocarbon group or an aromatic hydrocarbon group.X represents a halogen.Also, p is 1
It is a number expressed by ≦p<1.5. ) Examples of aluminum compounds represented by methylaluminum dichloride, ethylaluminum dichloride, n-propylaluminum dichloride, n-
Butylaluminum dichloride, n-hexylaluminum dichloride, n-octylaluminum dichloride, phenylaluminum dichloride, O-tolylaluminum dichloride, cyclohexylaluminum dichloride, methylaluminum dibromide, ethylaluminum dibromide, phenylaluminum dibromide, methylaluminum dichloride Examples include iodide. Among these, ethylaluminum dichloride is particularly preferred. Further, the above aluminum compound may be used alone or in a mixed system consisting of two or more kinds of aluminum compounds. In paragraphs (1), (2) and (3) above, the halogen compound used when reacting with the mixture of a halogen compound and an ether compound has the following formula: (a) General formula X ₂ (X is Cl, Br, or )
Halogen represented by (b) Interhalogen compound represented by the general formula XX'a (X and X' represent Cl, Br, or 1 or 3) (c) General A halogenated hydrocarbon represented by the formula R ₃ -X (R ₃ represents a linear alkyl group or branched alkyl group having 3 to 18 carbon atoms, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group) At least one type of halogen compound selected from hydrogen compounds. Examples of the halogen shown in (a) above include chlorine, bromine, and iodine, and examples of the interhalogen compound shown in (b) include bromine chloride, iodine chloride, iodine trichloride, and iodine bromide. . Further, as halogenated hydrocarbon compounds, there are compounds such as linear or branched alkyl halides, alicyclic halides, aromatic halides, and alkyl halides, but among these, linear or branched alkyl halides give preferable results. bring. Furthermore, among these, linear and branched primary alkyl halides and linear and branched secondary halides give particularly preferable results. Particularly preferred is n-butyl iodide. Furthermore, among halogen compounds, iodine gives the most favorable results. Further, as the ether compound used together with the above halogen compound, diethyl ether, di-n
-propyl ether, di-isopropyl ether, di-n-butyl ether, di-isoamyl ether, di-neopentyl ether, di-n-hexyl ether, methyl-n-butyl ether,
Examples include compounds such as methyl-isoamyl ether and ethyl-isobutyl ether. Among these, di-n-butyl ether and di-isocyamyl ether give particularly favorable results. The method for the above reaction is (1) a method in which a titanium trichloride composition is added to a system in which a halogen compound and an ether compound are mixed. (2) A method in which a titanium trichloride composition and an ether compound are brought into contact with each other in advance, and then a halogen compound is added to react. It is possible to carry out various forms such as. In addition, in the present invention, the organoaluminum compound represented by the general formula RlAlY ₃ -l used as the catalyst component (B) includes dimethylaluminum chloride, diethylaluminum chloride, di-
Examples include isobutylaluminum chloride, diethylaluminum bromide, diethylaluminium iodide, trimethylaluminum, triethylaluminum, diethylaluminium hydride, diethylaluminum ethoxide, and among these, diethylaluminium chloride is particularly preferred. Furthermore, when using a stereoregularity improver as the catalyst component (C), known compounds such as amines, ethers, esters, sulfur, halogens, benzene, azulene derivatives, organic and inorganic nitrogen and phosphorus can be used. I can do it. Specifically, triethylamine, tri-n-butylamine, diethyl ether, ethyl vinyl ether,
Methyl acrylate, methyl methacrylate, ethyl benzoate, ethyl P-anisate, methyl n-butyrate, γ-butyrolactone, ζ-caprolactone,
di-n-butyl sulfide, thiophenol,
Benzoyl chloride, methyl-p-methylbenzoate, tri-n-butyl phosphite, triphenyl phosphite, tri-n-butyl phosphine, triphenyl phosphine, tri-n-butyl phosphate, hexamethyl phosphoric acid triamide, etc. can be given. The amounts of the catalyst components (A) activated titanium trichloride solid catalyst, (B) organoaluminum compound, and (C) stereoregularity improver do not need to be particularly limited;
(C)/(A) = 0.1 to 10 molar ratio, preferably 0.5 to 5 molar ratio, and the concentration of component (B) in the polymerization tank is 1 to 100 mmol/(B)/(A)>1 mol The above ranges are preferably used. The order in which the catalyst components are added to the polymerization zone is not particularly limited, but component (A) is added at a high concentration in the absence of component (B).
Direct contact of component (C) may result in a decrease in activity, so in such cases it may be necessary to consider the order of addition. As a result of various studies, the present inventors determined that the amount of polymerization per gram of titanium trichloride solid catalyst should be reduced in the production of propylene-ethylene block copolymer.
By using 8000 g/g titanium trichloride solid catalyst or more, the various problems described above due to catalyst residues contained in the polymer will not occur even if the catalyst removal step is substantially omitted. It became clear. Propylene of the present invention using conventional catalyst systems
It was almost impossible to carry out the ethylene block copolymerization method and achieve a ratio of 8,000 g polymer/1 g titanium trichloride solid catalyst or more because the catalyst activity was low. Moreover, even if the above-mentioned catalytic activity can be achieved, the polymerization must be carried out for an extremely long time due to the economical decrease in catalytic activity, which is not possible in a practical manner. The composite catalyst system according to the present invention has a dramatic improvement effect in terms of catalytic activity compared to conventional catalyst systems, and the above catalytic activity is achieved in an extremely short time. In the method of the present invention, if it is desirable to further reduce the trace amount of catalyst residue remaining in the polymer, it is possible to add an extremely simplified catalyst residue removal step. For example, as proposed in Japanese Patent Application No. 51-96451, the above-mentioned trace amount of catalyst residue can be easily reduced by simply bringing the polymer powder into contact with a mixed gas of epoxide and alcohol. By carrying out propylene-ethylene block copolymerization using the composite catalyst system of the present invention, the formation of low molecular weight and low crystallinity polymers is suppressed, so the adhesive force of the polymer particles is small and the , problems such as a decrease in heat transfer efficiency due to agglomeration of the polymer and adhesion of the polymer to the inner wall of the polymerization tank;
Problems such as blockages in piping, powder hoppers, and silos during the transfer of polymer slurries or polymer powders are avoided. In terms of quality, propylene has extremely well-balanced physical properties of impact resistance and heat resistance.
An ethylene block copolymer is obtained. In the polymerization method carried out in the present invention, the polymerization is divided into two stages in the presence of the above composite catalyst system and substantially in the absence of an inert solvent. In the first stage, propylene alone is used in liquefied propylene. Or, add a small amount of ethylene to start the polymerization, and continue the polymerization in liquefied propylene or in the gas phase until the ethylene content in the polymer produced in the first step is 4% by weight or less. By polymerizing like this, the final polymer has 60 to 95
% by weight of crystalline polypropylene, followed in a second step by statistical copolymerization of propylene and ethylene in liquefied propylene or in the gas phase,
Alternatively, by homopolymerizing ethylene in the gas phase, 5 to 5% of the final polymer is added so that the ethylene content in the polymer produced in the second step is 10% by weight or more.
A method for producing a 40% by weight statistical copolymer of ethylene-propylene or a homopolymer of ethylene, or the second stage polymerization is further carried out in two stages by changing the mixing of ethylene and propylene in stages. The above method is used for polymerization, or the mixing ratio is continuously changed for polymerization, or the process from the first stage is repeated a plurality of times. When homopolymerizing propylene in the first step, a polymer with a good balance of impact resistance, heat resistance, and rigidity can be obtained by carrying out the second step polymerization following the first step. However, if you wish to further improve the surface gloss, impact strength, and degree of whitening upon impact, even if you sacrifice some rigidity,
In the first stage, a small amount of ethylene can be further added to carry out copolymerization. Specific embodiments of propylene-ethylene block copolymerization include (1) a method in which all polymerization steps are carried out in liquefied propylene, (2) a method in which the first stage polymerization is carried out in liquefied propylene, and a second stage in which the first stage polymerization is carried out in liquefied propylene. (3) A method in which the subsequent polymerization is performed in the gas phase; (3) A method in which the first stage polymerization is started in liquefied propylene, the polymerization is continued in the gas phase, and the second stage and subsequent polymerizations are performed in the gas phase. , etc., but the composite catalyst system in the present invention can be applied to any of the above polymerization embodiments,
Its effects are fully demonstrated. When polymerization is carried out in liquefied propylene, the polymerization is carried out at a temperature of 0 to 90°C, preferably 40 to 80°C, under a pressure capable of keeping the propylene in a liquid state, preferably 15 to 40°C.
Performed at Kg/cm ² (gauge pressure). In addition, when polymerization is carried out in the gas phase, the polymerization is carried out at a temperature below the temperature at which the resulting polymer softens, preferably at a temperature of 40 to 100%.
The temperature and pressure in °C are from normal pressure to 60 kg/cm ² (gauge pressure), preferably from 5 to 50 kg/cm ² (gauge pressure). In addition, at each stage of polymerization, in order to adjust the melt fluidity of the polymer, it is preferable to add a known molecular weight regulator such as hydrogen.
Statistical copolymerization of propylene can be carried out in the absence of the molecular weight regulator. The polymerization may be carried out continuously using one or more polymerization tanks. When polymerizing in liquefied propylene, a widely used tank reactor or loop reactor is preferably used. Furthermore, when polymerization is carried out in a gas phase, it is carried out in a stirred mixing tank type reactor, a fluidized bed reactor, or a stirred fluidized bed reactor. In order to explain the present invention more clearly, Examples and Comparative Examples are described below, but the present invention is not limited only by these Examples. The results are shown in Tables 1 to 4, and the physical property values in the tables were measured according to the following criteria. Melt index ASTM D1238-57T Vikatsu softening point ASTM D1525 Brittle temperature ASTM D746 Bending rigidity ASTM D747-58T Izot impact strength Measured at 20℃ and -20℃ according to ASTM D256. The ethylene content in all polymers was determined by a known infrared spectroscopy method. The intrinsic viscosity [η] was measured at 135°C in tetralin. Powder adhesion strength is determined by single-plane shear test method.
It was determined from the shear stress when the normal stress was extrapolated to 0. According to the findings of the present inventors, powder adhesion is 2
When it exceeds g/cm ² , handling of the powder becomes extremely difficult. In addition, the number of grams of polymer produced per gram of titanium trichloride solid catalyst (g polymer/g titanium trichloride solid catalyst) was expressed in pp./cat. Example 1 (1) Synthesis of catalyst (i) A 200-meter autoclave equipped with a stirrer was charged with 45.5 grams of hexane and 11.8 grams of TiCl ₄ , and the solution was kept at -10 to -5°C. A solution consisting of 43.2 parts of hexane and 9.4 parts of diethylaluminium chloride was added dropwise over 3 hours while stirring at 130 rpm. During this time, keep the temperature inside the autoclave at -10~
It was kept at -5°C. Next, the reaction solution was maintained at -10 to 0°C for 15 minutes, and then heated to 65°C over 1 hour. The reaction solution was kept under stirring at 65° C. for an additional 2 hours. The liquid phase was then separated from the solid and washed six times with 50 g of hexane. (ii) Hexane was removed from the reaction and the resulting dry product was suspended in 92 hexanes and to this was added 19.6 diisoamyl ether. After stirring the suspension at 35° C. for 1 hour, the resulting solid was separated from the liquid phase and washed 6 times with 50° C. of hexane. To the resulting ether-treated solid, add 40 _% of TiCl
A 60% by volume hexane solution was introduced and the suspension was kept under stirring at 70° C. for 2 hours. The liquid phase was then removed and diluted with 50% hexane for 10%.
Washed twice. The resulting solid was separated from hexane and dried. The titanium trichloride solid catalyst thus obtained is referred to as a titanium trichloride solid catalyst (). (2) Propylene-ethylene block copolymerization 200
1.9 g of titanium trichloride solid catalyst () and 20 g of diethyl amylminium chloride were added to an autoclave equipped with a stirrer. At the first stage,
Supply 150 liters of liquefied propylene, polymerization temperature 70℃
Polymerization was continued under these conditions until the polymerization amount reached 17.0 kg. Additionally, hydrogen was supplied during the polymerization to control the molecular weight. After the first stage was completed, a small amount of the polymer was sampled in order to measure [η] of the produced polymer. The polymerization time for the first stage was 2.5 hours. Furthermore, in the second stage, after setting the temperature inside the tank to 50℃, ethylene gas is supplied and statistical copolymerization of ethylene-propylene is carried out in the presence of hydrogen until the polymerization amount at this stage reaches 4.5 kg. I did it. During the polymerization, the ethylene concentration in the gas phase in the tank was 8.9 to 11.3 mol%, and the average gas phase ethylene concentration was 10.2 mol%. The polymerization time for the second stage was 1.9 hours. After the completion of the second stage, the polymer slurry was introduced into the upper part of the autoclave at 200 °C and 100 °C from the lower part.
of liquefied propylene was supplied to wash the soluble catalyst and soluble by-product polymer in the polymerization slurry, and at the same time, the polymer was extracted from the bottom of the tank. The obtained polymer was dried to obtain a white powdery polymer. Furthermore, the obtained polymer was granulated by adding known additives. The structure of the obtained polymer is shown in Table 1, and the physical properties are shown in Table 2. Example 2 Except that 3.9 ml of methyl methacrylate was added as a third component together with the catalyst during polymerization,
The operation was exactly the same as in Example 1. The average gas phase ethylene concentration in the second stage was 9.8 mol%. The polymerization time for the first stage was 3.1 hours, and the polymerization time for the second stage was 2.3 hours. The structure of the obtained polymer is shown in Table 1, and the physical properties are shown in Table 2. Comparative Example 1 The same operation as in Example 3 was carried out except that 6.7 g of pulverized activated titanium trichloride (grade name: TAC132) manufactured by Toho Titanium Co., Ltd. was used in place of the titanium trichloride solid catalyst. The average gas phase ethylene concentration in the second stage was 10.0 mol%. Further, the first stage polymerization required 2.1 hours, and the second stage polymerization required 1.6 hours. The obtained polymer was treated in exactly the same manner as in Example 1, but since there was a large amount of catalyst residue in the polymer and it was colored yellow during granulation, alcohol-heptane was further added to decompose the catalyst and extract the residue. After doing this,
After drying, known additives were added and granulation was performed. In addition, a blockage occurred in the piping when the polymer slurry was extracted from the polymerization tank to the cyclone, making it difficult to transfer the polymer slurry.During polymerization, the polymer adhered to the walls of the polymerization tank, making it difficult to remove heat and lowering the polymerization temperature. It was extremely unstable. The structure of the obtained polymer is shown in Table 1, and the physical properties are shown in Table 2.
Shown in the table. Example 3 (1) Synthesis of catalyst (i) After purging the reaction vessel in 1 with argon, 200 c.c. of dry hexane and 50 c.c. of titanium tetrachloride were added, and the solution was kept at -5°C. Then, a solution consisting of 150 c.c. of dry hexane and 58 c.c. of diethylaluminum chloride was added dropwise to the reaction system so as to maintain the temperature at -3°C. After the dropwise addition was completed, stirring was continued for an additional 30 minutes, then the temperature was raised to 70°C over 30 minutes, and stirring was continued for an additional hour. Then, the mixture was allowed to stand still, and the reduced product was separated into solid and liquid, and further washed with 200 c.c. of hexane to obtain 74.0 g of reduced product. (ii) 70 g of the obtained reduction product was slurried in n-decane, and the slurry was heat-treated at 140° C. for 2 hours at a slurry concentration of 0.2 g/cc. After the reaction, the supernatant was extracted and washed twice with 200 c.c. of hexane to obtain a titanium trichloride composition. The titanium trichloride composition thus obtained is referred to as a titanium trichloride composition (A). (iii) 11.0 g of titanium trichloride composition (A) was added to toluene.
Slurry to 55.0 cc and TiCl composition (A)/
₂ /di-isoamyl ether=1.0/0.1/1.0
Iodine and di-isoamyl ether were added in a molar ratio and reacted at 80°C for 1 hour to obtain a titanium trichloride solid catalyst. This is called a titanium trichloride solid catalyst (). (2) Block copolymerization of propylene-ethylene After evacuating an autoclave equipped with a 200 stirrer, propylene was pressurized to 300 mmHg (gauge pressure) and the operation of reducing the pressure to -500 mmHg (gauge pressure) was repeated three times. Next, 2.6 g of titanium trichloride solid catalyst (2) and 51 g of diethylaluminium chloride were added. First, in the first stage, 51.0 kg of liquefied propylene was injected under pressure, and the polymerization temperature was 70°C in the presence of hydrogen.
Polymerization proceeded in liquefied propylene. The amount of polymerization
When the weight reached 22.3 kg, a small amount of the polymer was immediately sampled in order to measure [η] of the produced polymer, and the unreacted monomer in the polymerization tank was purged to 2 kg/cm ² (gauge pressure).
The polymerization time for the first stage was 2.5 hours. In the second stage, ethylene gas and propylene gas were supplied, the pressure was increased to 10 Kg/cm ² (gauge pressure), and then the polymerization was carried out in the gas phase at a polymerization temperature of 60° C. in the presence of hydrogen. When the amount of polymerization reaches 1.4 kg, in order to measure [η] of the produced polymer, immediately sample a small amount of polymer and remove unreacted monomer in the polymerization tank by 6.5 kg.
Purged to Kg/cm ² (gauge pressure). The ethylene concentration in the second stage polymerization tank is 18.0~
It was 30.5 mol%, with an average of 24.0 mol%. Second
The stage polymerization time was 1.1 hours. Subsequently, in the third stage, after increasing the pressure with ethylene gas, ethylene gas and propylene gas were supplied, and the polymerization temperature was 70°C, the polymerization pressure was 10 Kg/cm ² (gauge pressure), and the polymerization was carried out in the gas phase in the presence of hydrogen. Polymerization was continued. During polymerization, in order to remove the polymerization reaction heat, the mixed gas in the polymerization tank is extracted at a flow rate of 18.4 ^m3 per hour, and after the mixed gas is heated to 50°C with a heat exchanger, it is pumped out from the bottom of the polymerization tank with a circulation compressor. , blew again. When the amount of polymerization reached 6.3 kg, circulation of the mixed gas was stopped and unreacted monomers in the polymerization tank were purged. The ethylene concentration in the polymerization tank in the third stage is 54.0~
It was 58.0 mol%, with an average of 55.0 mol%. Third
The stage polymerization time was 2.0 hours. The obtained polymer was transferred to a 200-liter autoclave with a stirrer, and 180 g of propylene oxide was added.
was added and stirred at 60° C. for 30 minutes to render the catalyst residue contained in the polymer harmless, and then dried to obtain a white powdery polymer. The obtained polymer was granulated by adding known additives, but the obtained pellets were not colored and had no particular problems. There were no problems such as blockage of pipes throughout the entire process of the experiment, and when the interior of the polymerization tank was inspected after the experiment, no polymer adhesion to the walls or polymer agglomeration was observed. The structure of the obtained polymer is shown in Table 1, and the physical properties are shown in Table 2. Comparative Example 2 Instead of the titanium trichloride solid catalyst (), crushed activated titanium manufactured by Toho Titanium Co., Ltd. (grade name:
Example 3 except that TAC132) 8.0g was used.
I performed the same operation. The average ethylene concentration in the second stage was 22.9 mol% and the average ethylene concentration in the third stage was 55.7 mol%. The polymerization times of the first, second, and third stages were 2.4 hours, 1.1 hours, and 2.0 hours, respectively.
It was time. When the obtained polymer is treated with propylene oxide in the same manner as in Example 3, there is a large amount of catalyst residue in the polymer, and the polymer is colored yellow during granulation. Therefore, alcohol-heptane was added to decompose the catalyst and extract the residue, followed by drying. Further, known additives were added and granulation was performed. In addition, when circulating the mixed gas in the third stage,
In the polymerization tank, polymers with minute particle size are scattered,
The mixed gas extraction line was blocked, making it impossible to operate satisfactorily. Furthermore, when the inside of the polymerization tank was inspected after the experiment, a large amount of polymer was found to have adhered to the walls. The structure of the obtained polymer is shown in Table 1, and the physical properties are shown in Table 2. It can be seen that by using the composite catalyst system according to the present invention, the polymerization activity is dramatically increased, and a propylene-ethylene block copolymer having an extremely well-balanced impact resistance, rigidity and heat resistance can be obtained.

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Claims (1)

[Claims] 1. In the first step, under conditions in which propylene is present in liquid form in the substantial absence of an inert solvent,
Polymerization is started by adding propylene alone or a small amount of ethylene, and polymerization is continued in liquefied propylene or in the gas phase.Subsequently, in the second and subsequent stages, polymerization is carried out in liquefied propylene or in the gas phase. In carrying out the statistical copolymerization of propylene and ethylene, (A) titanium tetrachloride was reduced with an organoaluminum compound and activated titanium trichloride solid catalyst, and (B) the general formula RlAlY ₃ -l ( R represents a linear alkyl group having 1 to 8 carbon atoms, or an alkoxy group; Y represents a halogen, hydrogen, or an alkoxy group; and l is a number represented by 2≦l≦3). Using a catalyst system consisting of the expressed organoaluminum compound or (C) a stereoregularity improver, the amount of polymerization per titanium trichloride solid catalyst was reduced.
A method for producing a propylene-ethylene block copolymer, characterized in that the content of the titanium trichloride solid catalyst is 8000 g/g or more. 2. The activated titanium trichloride solid catalyst reduces titanium tetrachloride with organoaluminium, and the resulting reduction product is further heat-treated at a temperature of 50 to 120 °C in the presence or absence of an inert solvent. The manufacturing method according to claim 1, which is a titanium trichloride solid catalyst obtained by further activating the heat-treated solid obtained. 3. Claim 2, wherein the activated titanium trichloride solid catalyst is a titanium trichloride solid catalyst obtained by reacting the obtained heat-treated solid with a mixture of a halogen compound and an ether compound. manufacturing method.