JPH0410889B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymerization method for providing a propylene block copolymer with high rigidity, high impact strength, and good flowability while suppressing by-production of highly active and low-crystal components. Prior Art Although crystalline polypropylene produced using a stereoregular catalyst has excellent properties such as rigidity and heat resistance, it has a problem of low impact strength, especially low impact strength at low temperatures. As a method to improve this point, a method is already known in which propylene and ethylene or other olefins are polymerized stepwise to produce a block copolymer (Japanese Patent Publication No. 11230/1973, Japanese Patent Publication No. 11230/1973,
No. 16668, Special Publication No. 1977-20621, Special Publication No. 1977-24593
No., JP 49-30264, JP 48-25781, JP 50-115296, JP 53-35789, JP 54
−110072 publications, etc.) However, propylene and ethylene are
When polymerized in stages or in multiple stages, the impact resistance is improved, but because it contains a copolymerized portion, it involves an industrial problem in that a large amount of low-crystalline polymer is produced as a by-product. Therefore, many attempts have been made to reduce the by-product amorphous content. On the other hand, titanium trichloride type catalysts are well known as olefin stereoregular catalysts, but they have low activity and require a decatalyzation step to remove catalyst residues from the produced polymer. It is known that introducing a magnesium compound into the solid component is effective as a method to greatly improve the activity (Special Publication No. 39
−12105, Special Publication No. 41676, and Special Publication No. 1977-
46269 publications). However, it is known that when olefins are polymerized by these methods, the activity is very high, but the stereoregularity is poor and the practical value is low. Therefore, in olefin polymerization using a Ziegler type catalyst containing a magnesium compound, various methods have been proposed to improve the stereoregularity of the resulting polymer (JP-A-47-9842, JP-A-Sho 50-
No. 126590, Japanese Unexamined Patent Publication No. 51-57789). These methods are characterized in that a solid catalyst component containing a titanium compound and a magnesium halide compound further contains an electron donor such as an ester or an amine. A method for producing propylene block copolymers using these catalyst systems has also been proposed (Japanese Patent Laid-Open Nos. 52-98045 and 1988-88049). However, these methods are unsatisfactory in practical terms because they produce a large amount of amorphous by-products. Furthermore, in order to improve this, Si-O was added during polymerization.
It was proposed to add an organosilicon component having -C or Si-N-C bonds (JP-A-58-
Publication No. 83016). As a result, the by-product amorphous content was greatly improved. However, in the method according to this publication, the molecular weight of the ethylene/propylene rubber part that affects impact resistance is small, and therefore the rubber produced is still easily extracted into the polymerization solvent, resulting in amorphous by-products, and Coalescence is sticky and tends to cause agglomeration or sticking of the polymer, leading to operational troubles. Additionally, this method seems to have a drawback in that the polymer has poor flowability within the mold. The flowability of a polymer in a mold is measured by spiral flow, and the factor for block copolymers that affects spiral flow is the viscosity of the crystalline polypropylene part synthesized in one step, and the lower this value, the higher the spiral flow. will improve. In the previously reported method, the molecular weight of the ethylene/propylene copolymer portion and/or polyethylene portion is small, so in order to match the viscosity of the entire polymer, the viscosity of the crystalline propylene portion formed in one step must be increased. Therefore, the spiral flow inevitably deteriorates, and as a result, the molding cycle becomes longer, which is inconvenient in practice. SUMMARY OF THE INVENTION The present invention aims to provide a solution to the above points and achieves this object by an improved process for producing propylene copolymers consisting of the use of specific catalysts and the implementation of specific steps. That is. Therefore, the method for producing a propylene copolymer according to the present invention includes at least step (2) in the method for producing a propylene copolymer by carrying out the following step () in the presence of the following catalytic catalyst (). polymerization of
It is characterized in that it is carried out in the coexistence of ZrCl ₄ , Ti(OC ₄ H ₉ ) ₂ Cl ₂ or (and) AlCl ₃ . () Catalyst This catalyst consists of a combination of the following components (A) to (C). (A) Solid catalyst component containing magnesium, titanium, and halogen as essential components (B) Organoaluminum compound (C) Electron donor () Process This process consists of the following (1) and (2), and the total ethylene content is This is a process for producing block polymers having a content of 3 to 40% by weight. (1) A step in which propylene alone or a propylene/ethylene mixture containing 5% by weight or less of ethylene is polymerized in one or multiple stages to form a polymer in an amount corresponding to 60 to 95% by weight of the total polymerization. (2) A process in which a propylene/ethylene mixture having an ethylene content of 20 to 100% by weight is polymerized in one stage or in multiple stages. Effects By producing a propylene copolymer using the method according to the present invention, a copolymer having high activity and stereoregularity and having a two-stage propylene/ethylene copolymer composition and/or a polyethylene portion having a high molecular weight can be produced. Can be manufactured. As a result, the molecular weight of the propylene/ethylene rubber part increases, which reduces the elution of by-product amorphous components, eliminates stickiness of the polymerization powder, and eliminates operational troubles due to polymer powder aggregation, etc. It was also cost effective. It has also been found that since the molecular weight of the propylene/ethylene copolymerized portion increases, it is possible to further reduce the molecular weight, thereby improving the spiral flow, that is, the fluidity of the polymer. That is, according to the present invention, a propylene block copolymer with high rigidity, good low-temperature impact strength, and good fluidity could be produced with high activity, at low cost, and without any operational trouble. DETAILED DESCRIPTION OF THE INVENTION Catalyst The catalyst used in the present invention consists of a combination of components A) to C). Note that the polymerization step () of the present invention consists of steps (1) and (2);
Alternatively, since steps (1) and (2) are carried out in the presence of a specified halogen-containing compound (hereinafter referred to as component (D)) (details will be described later), the catalyst of the present invention is a combination of components (A) to (D). It can also be said that it consists of The solid catalyst component is a highly active solid catalyst component containing magnesium, titanium, and halogen as essential components. In addition to the above-mentioned essential components, this solid catalyst component includes:
It may also contain other elements, organic compounds, etc. Typical of such components are electron donor compounds. Furthermore, this solid catalyst component may be diluted with an inorganic or organic diluent. Methods for producing such solid components are already known, and some suitable methods are exemplified below. (1) A method of manufacturing by grinding magnesium halide in the presence or absence of a grinding aid and co-pulverizing or contacting it with a titanium compound in a liquid state.
This may be further brought into contact with an electron donor and/or a halogenating agent (Japanese Patent Application Laid-Open No. 53-1979-1).
45688 and Japanese Patent Application Laid-open No. 55-90510). (2) By dissolving a magnesium compound in an electron donor and removing part or all of the electron donor complexed with the magnesium component using an electron donor extractant such as a halogenating agent or a reducing agent. , a method of producing a catalyst by precipitating a magnesium compound and contacting it with a titanium compound and, in some cases, a halogenating agent (Japanese Patent Application Laid-Open No. 1983-
No. 40293, JP-A-56-811, JP-A-58-183708
No., and Japanese Patent Application Laid-open No. 183709/1983). (3) A method of producing a catalyst by bringing an organomagnesium compound such as a Grignard reagent into contact with a halogenating agent, etc., and then contacting this with a titanium compound (JP-A-52-14672, JP-A-53-100986) (Refer to each publication). In producing this solid component, starting magnesium compound raw materials include (a) magnesium oxide, magnesium hydroxide, (b) magnesium carboxylates such as magnesium acetate and magnesium stearate, and (c) magnesium methoxide. alkoxymagnesium such as magnesium ethoxide, (d) allyloxymagnesium such as magnesium phenoxide and magnesium crezoxide, (e) magnesium dihalide such as magnesium chloride and magnesium bromide, (f) allyloxymagnesium Examples include halide derivatives such as magnesium halide, alkoxymagnesium halide, and hydroxymagnesium halide, (3) organomagnesium compounds such as Grignard reagents, and (3) complexes of organomagnesium compounds with electron donors and halides. Titanium compounds for treating such magnesium compounds include (a) Ti(OEt) ₄ , Ti(OisoPr) ₄ ,
Ti (OnBu) Tetraalkoxy titanium such as ₄ , (b)Ti
(OEt) ₃ Cl, Ti(OEt) ₂ Cl ₂ , Ti(OEt)Cl ₃ , Ti
(OisoPr) ₃ Cl, Ti (OisoPr) ₂ Cl ₂ , Ti (OisoPr)
Cl ₃ , Ti (OnBu) ₃ Cl, Ti (OnBu) ₂ Cl ₂ , Ti (OnBu)
Cl ₃ , Ti (OC ₈ H ₁₇ ) ₃ Cl, Ti (OC ₈ H ₁₇ ) ₂ Cl ₂ , Ti
(OC ₈ H ₁₇ ) Cl ₃ , Ti (OCH ₂ CH (C ₂ H ₅ ) C ₄ H ₉ )
Cl ₃ , Ti (OC ₆ H ₅ ) Cl ₃ , Ti (ortho-cresoxy)
Alkoxy titanium halide represented by Ti( _{OR)oX4-o such as Cl3, Ti(OCH2C6H5 ) Cl3 , ( c )}
Examples include titanium tetrahalides such as TiCl ₄ and TiBr ₄ . Particularly preferred among these is _TiCl4 . Alternatively, it may be a molecular compound in which TiX ₄ (where X represents a halogen) is reacted with an electron donor.
_TiCl4・_{CH3COCH3 , TiCl4 ・ CH3COOC2H5 ,}
TiCl ₄・C ₆ H ₅ COOC ₂ H ₅ , TiCl ₄・C ₆ H ₅ COCl,
_Examples include _{TiCl4.C4H4O .} An electron donor can be added to the solid component and is a preferred embodiment. As the electron donor, organic acid esters are preferred, and any generally known organic acid esters can be used. Examples of organic acid esters include aliphatic and alicyclic carboxylic acid esters derived from saturated or unsaturated or unsaturated aliphatic and alicyclic mono- or polyhydric carboxylic acids having about 1 to 12 carbon atoms, and 7 carbon atoms. Aromatic carboxylic acid esters derived from aromatic mono- or polyhydric carboxylic acids of about 15 to 15 are preferred. Specifically, organic acid esters include ethyl acetate, vinyl acetate, cellosolve acetate, methyl acrylate, methyl methacrylate, dibutyl maleate, diethyl malonate, ethyl α-phenylisobutyrate, and di-2-1,2-cyclohexanecarboxylate.
-Ethylhexyl, methyl benzoate, ethyl benzoate, cellosolve benzoate, ethyl p-toluate, ethyl o-methoxybenzoate, butyl o-propionylbenzoate, ethyl acetylsalicylate, diethyl phthalate, dihexyl phthalate, triethyl trimellitate etc. can be exemplified. These may be synthesized in-system from, for example, an acid halide and an alkoxy compound or alcohol. Moreover, two or more types of these can also be used in combination. The halogen atoms in TiX ₄ include fluorine, chlorine,
Examples include nitrogen, iodine, or mixtures thereof, with chlorine being particularly preferred. The quantitative relationship is as follows. That is, the Ti/Mg molar ratio in the solid catalyst is preferably in the range of 1×10 ^-2 to 1, and the Cl/Mg molar ratio is in the range of 0.5 to 1.
The organic acid ester/Mg molar ratio is preferably in the range of 1×10 ⁻² to 1. Organoaluminum Compound (Component B) The following are suitable as the organoaluminum component (B) of the present invention. (i) General formula R ¹ aR ² bAlXc(OR ³ )d (where R ¹ ,
R ² and R ³ are hydrocarbon residues having about 1 to 20 carbon atoms, which may be the same or different, or hydrogen, and X is a halogen atom. a+b+c+d=3 and 0
≦a≦3, 0≦b≦3, 0≦c<3, 0≦d<
3) an organoaluminum compound represented by (ii) the general formula MAlR ⁴ ₄ (where M is from periodic table 1A);
The alkali metal of the group ^R4 is a hydrocarbon residue having about 1 to 20 carbon atoms. ) is an organoaluminum compound represented by Specific examples of organoaluminum compounds belonging to (i) include a) trialkylaluminum such as triethylaluminum, triisobutylaluminum, and tri-n-hexylaluminum; b) diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquis chloride, alkyl aluminum halide such as ethyl aluminum dichloride, c) alkyl aluminum hydride such as diethyl aluminum hydride, diisobutyl aluminum hydride, d) alkyl aluminum alkoxide such as diethyl aluminum ethoxide, diethylaluminum butoxide, diethylaluminum phenoxide. Alternatively, allyloxide etc. can be used. These can be used alone or in combination of two or more. They can also be treated with other compounds to modify them and produce similar results.
It can also be used as R ¹ aR ² bAlXc(OR ³ )d. For example, it can be used as an alkyl halide by mixing triethyl aluminum and an alkyl halide, or it can be used as an alkyl aluminum alkoxide from triethyl aluminum and an alcohol or ketone. Compounds belonging to (ii) include LiAl(C ₂ H ₅ ) ₄ ,
LiAl(C ₄ H ₉ ) ₄ can be mentioned. The amount of organoaluminum compound (B) used is 0.5 to 1000 by weight relative to the solid catalyst component, as too little will cause insufficient activation of the solid catalyst, and too much will cause activation due to overreduction, etc. It is preferably within the range of . Electron Donor (Component C)) The following are suitable as electron donors for improving the stereoregularity of propylene polymers. ₍ ⁱ ) General formula R ⁵ _e ^{R 6} _f Si (OR ^{7 )} _g indicates a halogen atom. Here, e+f+g+h=4, 0≦e≦3,
0≦f≦3, 1≦g≦4, 0≦h≦3). This compound can also be synthesized in-system. For example, from phenyltrichlorosilane and an alkoxy-containing compound or alcohol, Si-O-C
Compounds having bonds can also be synthesized. Specific examples of (i) include ethyl silicate, butyl silicate, phenyl silicate, methyltriethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltriphenoxysilane, and vinyltriethoxysilane. Examples include silane, dimethyldimethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, trimethylmethoxysilane, triphenylmethoxysilane, and chlorotrimethoxysilane. (ii) Specific examples of ester compounds (ii) include ethyl acetate, cellosolve acetate, methyl methacrylate, diethyl maleate, ethyl α-phenylisobutyrate, ethyl benzoate, ethyl o-methoxybenzoate, diethyl phthalate, and phthalate. Examples include dihebutyl acid. (iii) Ether compounds Specific examples of (iii) include isoamyl ether, diphenyl ether, tetrahydrofuran, and cineol. (iv) Other electron donors Examples include peroxides such as diα-cumyl peroxide, phosphorus-containing compounds such as triethyl phosphite, and amine compounds such as 2,2,6,6-tetramethylpiperidine. can. Among these, preferred is the organosilicon compound (i). The electron donor of component C) is preferably used in a molar ratio of organosilicon compound/Al used during polymerization in the range of 0.01 to 1.0. Particularly preferably 0.05~
It is within the range of 0.5. In addition, these electron donors can also be used individually or in combination of two or more types. Halogen-containing compounds (component D)) In order to increase the molecular weight in the second polymerization step, improve the flowability of the polymer and reduce the extracted rubber components, ZrCl ₄ , Ti(OC ₄ H ₉ ) It is effective to introduce _{2Cl2 or AlCl3} . These can be used alone or in the form of a complex with an electron donor, and it is also possible to use two or more of these in combination. The halogen-containing compound of component D) is a halogen atom/Al in the halogen-containing compound used during polymerization.
It is preferable that the atomization is within the range of 0.01 to 1. The halogen compound can be added at any time when the effects of the present invention are observed. It is preferably added before propylene/ethylene copolymerization in the second polymerization step. Polymerization Step The polymerization step of the present invention, which is carried out in the presence of the catalyst, consists of at least two stages. Steps (1) and (2)
It is industrially advantageous to carry out the steps in this order. Step (1) In step (1), propylene alone or a propylene/ethylene mixture having an ethylene content of 5% by weight or less, preferably 0.5% by weight or less is fed to the polymerization system having the catalyst, and the polymerization is carried out in one stage or in multiple stages. An amount of polymer corresponding to 60-95% by weight of the total polymerization amount is formed. If the ethylene content in the propylene/ethylene mixture in step (1) is higher than this, the bulk density of the final copolymer will decrease and the amount of low crystalline polymer by-product will increase significantly. Furthermore, when the polymerization ratio is at the extreme end of the above range, the same phenomenon occurs as when the ethylene content in the propylene/ethylene mixture is high. On the other hand, if the polymerization ratio is made larger than the above range, the by-product of the low crystalline polymer tends to be reduced, but this is not preferable because the impact strength, which is the purpose of block copolymerization, decreases. The polymerization temperature in step (1) is 30 to 90°C, preferably
The temperature is about 50-80℃. Polymerization pressure is 1~30Kg/
It is about ^cm2 . In step (1), it is preferred to use a molecular weight regulator so as to give favorable results in the fluidity of the final polymer. Hydrogen is preferred as the molecular weight regulator. Step (2) In step (2), a propylene/ethylene mixture with an ethylene content of 20 to 100% by weight is further introduced to produce 1
The polymer is formed in an amount corresponding to 5 to 40% by weight of the total polymer in stages or in multiple stages. If the polymerization ratio in step (2) is less than the above range, the impact resistance (especially low temperature impact resistance) will be poor, and if it exceeds the above range, the by-product of low crystalline polymer will greatly increase and the viscosity will increase. Significant. In step (2), other comonomers may be present. Examples of suitable comonomers include α-olefins such as 1-butene, 1-pentene, and 1-hexene. The polymerization temperature in step (2) is 30 to 90°C, preferably 50°C.
~80℃, about. Polymerization pressure is 1 to 30Kg/cm ²
That's about it. When moving from step (1) to step (2) or even within step (2), it is preferable to purge propylene gas (including ethylene gas in some cases) and hydrogen gas before moving to the next stage. . In step (2), a molecular weight regulator may or may not be used depending on the purpose. That is, when it is desired to increase the impact resistance of the final polymer, it is preferable to carry out this step in the substantial absence of a molecular weight modifier, whereas when emphasis is placed on transparency, gloss whitening, etc., the molecular weight modifier is preferably carried out. Can be used. Note that among steps (1) and (2), at least step (2)
As mentioned above, is carried out in the presence of the halogen-containing compound (D). Polymerization Method The copolymer according to the present invention can be produced by any of the batch, continuous, and semi-continuous methods. In addition, heptane or other inert hydrocarbons or the monomer itself used can be used as a medium,
It is also possible to carry out the process in a gaseous monomer without using a medium, or to carry out the process in combination. It is also possible to carry out preliminary polymerization, that is, polymerization conducted under milder conditions than the main polymerization, before the solid catalyst is subjected to the main polymerization. Experimental Examples Example 1 1) Synthesis of solid catalyst component (A) Dehydrated and deoxygenated n-heptane was placed in an autoclave with an internal volume of 10 liters that was sufficiently purged with nitrogen.
2.5 liters, then 2.0 mol of _MgCl2 ,
3.9 mol of Ti(O-nBu) ₄ , then n-C ₄ H ₉ OH
0.09 mol was introduced and reacted at 90°C for 2 hours to form a homogeneous solution. After the reaction was completed, the temperature was lowered to 40°C, and then methylhydropolysiloxane (20 centistokes) was added.
300 ml was introduced and allowed to react for 3 hours.
When the generated solid component was washed with n-heptane and a portion was taken out for compositional analysis, it was found that Ti = 14.2
% by weight, Mg=4.3% by weight. An amount equivalent to 1.2 moles of Mg atoms of the above reaction product was slurried with n-heptane to a concentration of 320 g-solid/liter, and 2.0 moles of SiCl ₄ was added.
The mixture was introduced at 30°C for 1 hour and reacted at 30°C for 30 minutes. Then add 0.155 mol of diheptyl phthalate to 30
The mixture was introduced at 50°C for 30 minutes and reacted at 50°C for 1 hour.
After the reaction was completed, it was washed four times with 5 liters of n-heptane. Next, 1.0 liter of titanium tetrachloride was introduced at 30°C and reacted at 90°C for 2 hours. After the reaction is complete,
The supernatant was taken out, and then the same amount of TiCl ₄ was introduced and reacted at 90° C. for 2 hours. After the reaction was completed, the supernatant was taken out and washed four times with 5 liters of n-heptane. Furthermore, 3 liters of n-heptane was introduced, and the mixture was stirred at 70°C for 2 hours. After removing the supernatant, it was washed three times with 5 liters of n-heptane. 275 milliliters of TiCl ₄ was introduced again, and the reaction was carried out at 95° C. for 2 hours. After the reaction, n-heptane 5
A solid catalyst component (A) was obtained by washing with a liter bottle five times. The composition of the solid catalyst component is Ti = 2.9% by weight, Mg =
15.4% by weight, diheptyl phthalate = 20.8% by weight. 2) Prepolymerization In a stainless steel stirred tank with an internal volume of 1.5 liters equipped with a stirring and temperature control device, add 500 ml of n-heptane that has been sufficiently dehydrated and deoxidized.
4.3 grams of triethylaluminum (B), 0.45 grams of diethylaluminum chloride (B), and 20 grams of solid catalyst component (A) were introduced. Temperature inside stirring tank 25℃
Then, propylene was introduced at a constant rate and polymerization of propylene was carried out for 30 minutes. After the polymerization was completed, it was thoroughly washed with n-heptane. The amount of polymerized propylene is
There were 0.7 grams of polypropylene per gram of solids. 3) Polymerization After the inside of the stirred polymerization reactor with an internal volume of 150 liters was sufficiently replaced with propylene, 50 liters of n-heptane, 2.3 grams of the prepolymerized catalyst (A), 25.0 grams of triethylaluminum (B), and diphenyl were added. 10.7 grams of dimethoxysilane (C) were introduced at 60° C. under a propylene atmosphere. In the first stage polymerization, the polymerization reactor was heated to 65° C., and propylene was introduced at a constant rate of 9.6 kg/hour for 3 hours. During this time, hydrogen was also introduced so that the hydrogen concentration in the gas phase was 3.0% by volume. After 3 hours, stop introducing propylene and hydrogen and 1.5
Polymerization was continued at 65°C for an additional hour. Thereafter, the gas in the gas phase was purged until the pressure in the gas phase reached 0.2 Kg/cm ² G (here, a portion of the polymer produced in the first stage was extracted to examine its physical properties). Then, 20.5 grams of zirconium tetrachloride (D) was introduced at 65° C. under a propylene atmosphere. The second stage polymerization was carried out by feeding a mixture of propylene/ethylene in a weight ratio of 20/80 at a constant rate of 2.95 kg/hour for 1.5 hours. The polymerization temperature is 65°C. The polymer slurry thus obtained was centrifuged to separate the polymer, and then dried in a dryer to obtain 29.8 kg of product powder. The bulk density of this product was 0.492 g/cc. The details of the results were as shown in Table 1. Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that zirconium tetrachloride was not used as the polymerization additive (D), and the results shown in Table 1 were obtained. In this case, powder agglomeration was observed in the dryer due to a by-product of low crystallinity polymerization. Example 2 After sufficiently replacing the inside of a stirred polymerization reactor with an internal volume of 1.5 liters with propylene, 500 liters of n-heptane was added.
milliliter, 15 milligrams of prepolymerized catalyst (A) described in Example 1 as catalyst, triethylaluminum
(B) 250 mg diphenyldimethoxysilane
(C) 107 mg was introduced under a propylene atmosphere at 60 °C. In the first stage polymerization, after adding hydrogen in an amount to give a total MFR of about 6, propylene was introduced at a constant rate of 55.9 g/hour for 3 hours at a polymerization temperature of 65°C. After 3 hours, the introduction of propylene was stopped, and the polymerization was continued at 65°C for an additional 1.5 hours. Thereafter, the gas phase was purged until the pressure of the gas phase reached atmospheric pressure. Here, 58.3 milligrams of dichlorodibutoxytitanium (D) was introduced under a propylene atmosphere. In the second stage polymerization, a propylene/ethylene mixture with a weight ratio of 20/80 was mixed at a rate of 18.2 g/hour to 1.5
This was carried out by supplying for an hour. The polymerization temperature is
It is 65℃. The polymer slurry thus obtained was centrifuged to separate the polymer, which was then dried to obtain 160.5 g of powder. The bulk density of this product was 0.462 g/cc. Furthermore, by drying the liquid, 4.16 g of by-product amorphous matter was obtained. The details of the results were as shown in Table 1. Example 3 Polymerization was carried out in the same manner as in Example 2, except that dichlorodibutoxytitanium was changed to AlCl ₃ as shown in Table 1 as the polymerization additive (D), and the results shown in Table 1 were obtained. Comparative Examples 2 and 3 Polymerization was carried out in the same manner as in Example 2, except that FeCl ₃ or SiCl ₄ was used as the polymerization additive (D), and the results shown in Table 1 were obtained. Analysis of results, etc. (1) Polymerization ratio in each step From the pressure and gas composition analysis of the gas phase in each step,
Calculate the amount of dissolved monomers and the amount of unreacted monomers, estimate the amount of each monomer converted to polymer from the difference between the amount of feed monomers and the amount of unreacted monomers, and calculate the polymerization ratio and C ₃ /C _double The combined content was determined. The amount of conversion to the polymer obtained here is approximately the same as the amount of polymer obtained by separately conducting the first stage polymerization and continuous polymerization under the same conditions as in the example and the amount of polymer obtained in the example. Agreed. (2) Evaluation of physical properties The powdered polymers obtained in each of the Examples and Comparative Examples were pelletized using an extruder under the same conditions and with the following additives. The obtained pellets were injection molded to form a sheet with a thickness of 4 mm, and the physical properties of the sheet were evaluated. (a) Additive combination 2,6-di-tert-butylphenol 0.1% RA1010 (manufactured by Ciba Geigy) 0.05% Calcium stearate 0.01% Talc 0.3% (b) Various physical property values were measured by the following methods. MFR: ASTM-D1238 condition L Flexural modulus: ASTM-D790 Izot impact strength (notched): ASTM-
D256 MFR2: MFR2 is the MFR of the polymer produced in step 2 derived from the following formula from step 1 and the overall MFR measured in accordance with ASTM-D1238.
This is the estimated calculated value. a log (MFR1) + b log (MFR2) = c log (MFRA) a: Weight of polymer produced in one stage obtained by carrying out first stage polymerization and continuous polymerization under the same polymerization conditions as in the example b : Weight of the polymer produced in the second stage determined from the difference in weight between the entire polymer obtained from the example and the first stage polymer obtained by separate polymerization c: Weight of the entire polymer obtained from the example MFRA: MFR of the entire polymer measured according to ASTM-1238 MFR/: MFR of the polymer produced in one step obtained by separate polymerization, measured according to ASTM-1238. Low crystalline polymer by-product rate :(Low crystal polymer weight)/
(product powder weight)

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Claims (1)

[Claims] 1. In the presence of the following catalyst (), the following step ()
In the method for producing a propylene copolymer by carrying out at least the polymerization in step (2), ZrCl ₄ , Ti
A method for producing a propylene copolymer, which is carried out in the coexistence of (OC ₄ H ₉ ) ₂ Cl ₂ or (and) AlCl ₃ . () Catalyst This catalyst consists of a combination of the following components (A) to (C). (A) Solid catalyst component containing magnesium, titanium, and halogen as essential components (B) Organoaluminum compound (C) Electron donor () Process This process consists of the following (1) and (2), and the total ethylene content This is a process for producing a block copolymer in which the amount of copolymer is 3 to 40% by weight. (1) Propylene alone or a propylene/ethylene mixture with an ethylene content of 5% by weight or less is polymerized in one or multiple stages to produce 60 to 95% of the total polymerized amount.
(2) A step of polymerizing a propylene/ethylene mixture having an ethylene content of 20 to 100% by weight in one or more stages.