JPH0859766A - Production of high-rigidity propylene-ethylene block copolymer - Google Patents

Abstract

PURPOSE: To obtain the subject copolymer excellent in both rigidity and impact resistance, useful for various molded products, by two-stage copolymerization between ethylene and propylene using a specific catalyst so that its melt index and melt flow rate satisfy a specific relationship. CONSTITUTION: A polymerization is carried out between ethylene and propylene using a catalytic system composed of a solid catalyst comprising Ti, Mg, a halogen and a polycarboxylic ester, an organoaluminum compound and a compound of formula I (R<4> and R<5> are each a hydrocarbon group; R<6> is the same as R<4> , etc.; (x+y+z)=4; (x) is 0-2; (y) and (z) are each 1-3) to produce a polymer P1 with its maximum melt flow rate [MFR(h)] and minimum melt flow rate [MFR(1)] satisfying the relationship II so as to account for 60-95wt.% of the amount of the whole polymer, followed by feeding further ethylene and propylene to the system to produce a polymer P2 so as to account for 5-40wt.% of the amount of the whole polymer so that the melt index of P2 [MFR(ii)] and that of P1 [MFR(i)] satisfy the relationship of formula III, and then the objective copolymer is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a highly rigid molding propylene / ethylene block copolymer. More specifically, the present invention relates to a method for producing the polymer, which gives a molded article having high rigidity and high impact resistance without adding any special additive.

[0002]

2. Description of the Related Art Crystalline polypropylene (hereinafter sometimes simply referred to as polypropylene) as a general-purpose resin has high rigidity, hardness, tensile strength and heat resistance. However, the impact resistance is insufficient, and there is a problem that it is difficult to use for a molded product that is subjected to a mechanical shock or is used at a low temperature. In addition, other general-purpose resins such as A
When compared with BS resin or high impact polystyrene resin, not only impact resistance but also rigidity is poor. For specific applications of polypropylene and further for expanding demand, it is required to further improve not only the above-mentioned impact resistance but also rigidity. Crystalline polypropylene produced using a stereoregular catalyst has excellent properties such as rigidity and heat resistance, but on the other hand, it has a problem that impact strength, especially impact resistance at low temperature, is low. It was restricted. Therefore, as a method for solving this problem, a method of randomly or block copolymerizing propylene with another α-olefin such as ethylene is known. The obtained random copolymer has insufficient improvement in low-temperature impact resistance as compared with polypropylene, and its rigidity, strength, heat resistance and the like are rapidly lowered as the ethylene content is increased. Similarly, the block copolymer has significantly improved low-temperature impact resistance as compared with polypropylene, but has reduced rigidity, hardness, heat resistance and the like. Many methods have been proposed to improve the above-mentioned drawbacks of block copolymers.

For example, in JP-A Nos. 50-115296, 52-4588 and 53-35879,
A method for carrying out block copolymerization of propylene and ethylene in multiple stages is proposed. Also, for example, Japanese Patent Publication No. 47-8
No. 207, No. 49-13231, No. 49-13514
No. 1 proposes an improved method of adding a third component to the catalyst. Further, JP-A-55-764 and 54-15209
No. 5, No. 53-29390, and Japanese Patent Publication No. 55-8011 propose an improved method using a specific catalyst. However, the above proposals are based on polypropylene (homopolymer).
Is a technique for alleviating the problem of reducing the degree of decrease in the rigidity of the block copolymer obtained as compared with the above method, and still enables the rigidity value equal to or higher than that of the homopolymer. Has not arrived. In addition, JP-A-58-2018
No. 16 proposes a method for producing a high-rigidity propylene / ethylene block copolymer having rigidity equal to or higher than that of polypropylene, but improvement in impact resistance was insufficient.

[0004]

In view of the state of the art described above, a propylene / ethylene block copolymer which can obtain a molded product having high rigidity and high impact resistance without adding a special additive. As a result of extensive studies to invent a method for producing a polymer, the inventors have found that the copolymer can be obtained by producing the polymer under the limited conditions described below, and have reached the present invention. As is apparent from the above description, an object of the present invention is to provide a method for producing a propylene / ethylene block copolymer suitable for a molded article having high rigidity and high impact resistance.

[0005]

Means for Solving the Problems The present invention includes the following (1):
It is composed of (2). (1) Solid catalyst component (A) containing titanium, magnesium, halogen, and polycarboxylic acid ester as essential components, an organoaluminum compound (B), and a general formula R ⁴ _x R
⁵ _y Si (OR ⁶ ) _z (wherein R ⁴ and R ⁶ are hydrocarbon groups, R
⁵ represents a hydrocarbon group or a hydrocarbon group containing a hetero atom, and x + y + z = 4,0 ≦ x ≦ 2,1 ≦ y ≦ 3,1
≦ z ≦ 3. ) An organosilicon compound (C) represented by
Polymerization process mainly comprising propylene by using a catalyst system in which two or more polymerization vessels are connected in series as the first stage, and supplying a monomer of ethylene / (ethylene + propylene) = 0 to 5% by weight ( I) is carried out to obtain a total polymerization amount of 60
.About.95% is produced, and as the second stage, one or more tanks of polymerization reactor are used, and ethylene / (ethylene + propylene) = 10 to 1
A method for producing a propylene / ethylene block copolymer, characterized in that a polymerization step (II) containing a relatively large amount of ethylene is produced in an amount of 5 to 40% by weight based on the total amount of polymerization by supplying 00% by weight of a monomer. In, the maximum value of the melt flow rate of the polymer obtained in each tank of the polymerization step (I) (hereinafter M
FR (h)) and the minimum value (hereinafter referred to as MFR (l)) have a relationship of 0.1 ≦ Log (MFR (h) / MFR (l)) ≦ 1, and mainly propylene. MFR (i) of the polymer obtained in the polymerization step (I) and M of the polymer obtained in the polymerization step (II) containing a relatively large amount of ethylene.
A process for producing a high-rigidity propylene / ethylene block copolymer, which is characterized in that it is produced so as to have a relationship of 3 ≦ Log (MFR (i) / MFR (ii)) ≦ 7 with FR (ii). (2) The production method according to the above item 1, wherein the molar ratio of the organosilicon compound (C) to the organoaluminum compound (B) is (B) / (C) = 1 to 15.

The structure and effect of the present invention will be described in detail below. In the present invention, a solid catalyst component (A) containing at least a magnesium atom, a titanium atom, a halogen atom, and a polyvalent carboxylic acid ester, an organoaluminum compound (B) and an electron donating compound (C) are used as a polymerization catalyst. Although the resulting highly stereoregular catalyst system is used, there is no particular limitation on these catalysts, and it is possible to use a known catalyst system which gives various highly stereoregular polypropylenes. Examples of the method for producing such a solid catalyst component (A) include, for example, JP-A-50-108385 and JP-A-50-38585.
-12590, 51-20297, 51-2
8189, 51-64586, 51-9288
No. 5, No. 51-136625, No. 52-87489
No. 52-100596, No. 52-147688
No. 52-104593, No. 53-2580, No. 53-40093, No. 53-40094, No. 55-.
135102, 55-135103, 55-1
52710, 56-811, 56-11908.
No. 56, No. 56-18606, No. 58-83006, No. 58-138705, No. 58-138706, No. 5
8-138707, 58-138708, 58
138709, 58-138710, 58-
No. 138715, No. 60-23404, No. 61-21
No. 109, No. 61-37802, No. 61-37803
No. 62-104810 and No. 62-104811.
No. 62-104812 and No. 62-104813.
No. 63-54405 and the like.

Specific examples of the polyvalent carboxylic acid ester used in the solid catalyst component (A) include:
It is an ester of phthalic acid, maleic acid, substituted malonic acid, etc. and an alcohol having 2 or more carbon atoms. In the present invention, there are various magnesium compounds used in the above (A), but magnesium compounds with or without reducing ability are used. Examples of the former include dimethyl magnesium, diethyl magnesium, dipropyl magnesium,
Dibutyl magnesium, ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride and the like can be mentioned. Examples of the latter include magnesium halides such as magnesium chloride, magnesium bromide and magnesium iodide, magnesium methoxy chloride, alkoxy magnesium chloride such as ethoxy magnesium chloride, ethoxy magnesium, isopropoxy magnesium and butoxy magnesium. Mention may be made of alkoxy magnesium, magnesium laurate, magnesium carboxylates such as magnesium stearate and the like. Of these, particularly preferred compounds are magnesium halide, alkoxy magnesium chloride and alkoxy magnesium.

The titanium compound used as the solid catalyst component (A) in the present invention is usually Ti (OR) _A X.
_A compound represented by _4-A (R is a hydrocarbon group, X is a halogen, and 0≤A≤4) is most suitable. Specifically, TiCl
₄ , Titanium tetrahalide such as TiBr ₄ , Ti
Trihalogenated alkoxytitanium such as (OCH ₃ ) Cl ₃ and Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OCH ₃ ) ₂
Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ and other dihalogenated dialkoxy titanium, Ti (OCH ₃ ) ₃ Cl, Ti
Monohalogenated trialkoxy titanium such as (OC ₂ H ₅ ) ₃ Cl, Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ )
_{Tetraalkoxytitanium} such as ₄ , and particularly preferred is TiCl ₄ . In the preparation of the solid catalyst component (A), other electron donors such as alcohol, ether, phenol, silicon compound, aluminum compound and the like are made to coexist as necessary, in addition to the above titanium compound, magnesium compound and polyvalent carboxylic acid ester. be able to.

The organoaluminum compound (B) used in the present invention has a general formula of AlR ² _m R ³ _n X.
_{3- (m + n)} (wherein R ² and R ³ represent a hydrocarbon group or an alkoxy group, X represents a halogen, and m and n are 0 ≦
An arbitrary number of m ≦ 3, 0 ≦ n ≦ 3, 1.5 ≦ m + n ≦ 3 is shown. ) An organoaluminum compound represented by Specific examples include trimethyl aluminum, triethyl aluminum, tri-n-propyl aluminum, tri-n-butyl aluminum, and tri-i-.
Examples thereof include butyl aluminum, diethyl aluminum chloride, di-n-propyl aluminum monochloride, diethyl aluminum iodide, methyl aluminum sesquichloride, ethyl aluminum sesquichloride, ethoxydiethyl aluminum and the like. These organoaluminum compounds (B) can be used alone or in combination of two or more.

The electron donor component (C) used in the present invention is represented by the general formula R ⁴ _x R ⁵ _y Si (OR ⁶ ) _z (wherein R ⁴ and R ⁶ are hydrocarbon groups, and R ⁵ is carbonized). Indicating a hydrogen group or a hydrocarbon group containing a hetero atom, x + y + z =
4, 0 ≦ x ≦ 2, 1 ≦ y ≦ 3, 1 ≦ z ≦ 3. ) Organosilicon compounds represented by Specific examples thereof include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, n-propyltrimethoxysilane, n.
-Propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, i-butyltrimethoxysilane, i-butyltriethoxysilane, t- Butyltrimethoxysilane, t-butyltriethoxysilane, n-pentyltrimethoxysilane, n-pentyltriethoxysilane, neopentyltrimethoxysilane, neopentyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, Dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-i-propyldimethoxysilane, di-n-butyldimethoxysilane , Di-i-butyldimethoxysilane, di-t-butyldimethoxysilane, di-n-pentyldimethoxysilane, dineopentyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, Cyclohexyltrimethoxysilane,
Cyclohexyltriethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane,
3-isocyanatopropyltriethoxysilane, 2-
(3-Cyclohexenyl) ethyltrimethoxysilane etc. can be illustrated. These organosilicon compounds can be used alone or in admixture of two or more kinds at any ratio. Among these, particularly preferred organosilicon compounds are di-i-propyldimethoxysilane, t-butyltriethoxysilane, t-butyltrimethoxysilane, i-butyltrimethoxysilane and cyclohexyltrimethoxysilane. The preferable addition amount of the organosilicon compound (C) is a molar ratio (B) / (C) of 1 to 15 with respect to the organoaluminum compound (B). If the addition amount is small, the improvement of rigidity is insufficient and too large. And the catalytic activity is reduced, which is not practical.

The solid catalyst component (A) is then used in combination with the organoaluminum compound (B) and the aforementioned organosilicon compound (C) as a catalyst for the polymerization of propylene, or more preferably, an α-olefin is reacted. The pre-activation used as a pre-activated catalyst is 0.3 to 20 mol of organoaluminum (B) with respect to 1 mol of titanium in the solid catalyst component (A), and 1 minute to 0 to 50 ° C.
It is desirable to react the α-olefin with 0.1 to 10 mol, preferably 0.3 to 3 mol for 20 hours. The reaction of α-olefin for preactivation can be performed in an aliphatic or aromatic hydrocarbon solvent, or in a liquefied α-olefin such as liquefied propylene or liquefied butene-1 without using a solvent, and vaporized ethylene, propylene or the like. It is also possible to react in phases. Further, the α-olefin polymer or hydrogen obtained in advance can be made to coexist. Furthermore, the organic silane compound (C) can be added in advance in the preliminary activation. The α-olefin used for preactivating is ethylene, propylene, butene-1, hexene-
1, heptene-1, other linear monoolefins, 4
-Methyl-pentene-1, 2-methyl-pentene-1,
Branched chain monoolefins such as 3-methyl-butene-1, styrene and the like. These α-olefins may be used as a mixture of α-olefins to be polymerized. After the completion of the preliminary activation, the solvent, the organoaluminum compound and the unreacted α-olefin and the organoaluminum compound can be filtered off, removed by decantation, or dried to be used as a powder or granular material.

The pre-activated catalyst thus obtained contains propylene as n-hexane, n-heptane, n
-Slurry polymerization carried out in a hydrocarbon solvent such as octane, benzene or toluene, or bulk polymerization and gas phase polymerization carried out in liquefied propylene. In the case of slurry polymerization, the polymerization temperature is usually 20 to 90 ° C., preferably 5
The temperature is 0 to 80 ° C., and the polymerization pressure is 0.1 to 5 MPa. In the case of gas phase polymerization, the polymerization temperature is usually 20 to
It is 150 degreeC and superposition | polymerization pressure is implemented at 0.3-5 MPa. Hydrogen is usually used to control the molecular weight, and the MFR of the polymer obtained is carried out in the range of 0.1 to 1000.

The composition for supplying the monomer in the polymerization step (I) is ethylene / (ethylene + propylene) = 0 to 5% by weight. If the amount of ethylene is more than 5% by weight, there is a drawback in that the physical properties of polypropylene such as rigidity and heat resistance deteriorate.

As the third component of the monomer, 1-butene, 4-methylpentene-1, styrene, non-conjugated dienes and the like can be added to propylene in an amount of 0 to 10%.

The polymerization amount in the polymerization step (I) is 6 with respect to the total amount of the propylene / ethylene block copolymer finally obtained.
It is 0 to 95% by weight. If the amount of polymerization is less than the above range, the rigidity of the product will be deteriorated, and if it is too large, the improvement of low temperature impact strength will be insufficient. The polymerization in the polymerization step (I) is carried out using two or more polymerization vessels connected in series, and the maximum (MFR (h)) and minimum (MFR (MFR (h)) of the melt flow index of the polymer obtained in each tank are obtained. The relationship with l)) is preferably 0.1 ≦ Log (MFR (h) / MFR (l)) ≦ 1, and more preferably 0.2 ≦ Log (MFR (h) / MFR (l)) ≦ 0. ．
It is 5. When the MFR ratio is smaller than the above range, the rigidity of the product is lowered, and when it is large, the tensile elongation and impact resistance of the finally obtained propylene / ethylene block copolymer are lowered, which is not preferable.

In the polymerization step (II), the polymerization temperature is usually 20 to
80 ° C, preferably 40-70 ° C, pressure 0.1-5MP
a. Hydrogen is usually used to control the molecular weight, and the hydrogen concentration is 0.1 to 10 mol% in the gas phase. The ratio of ethylene and propylene fed to the polymerization step (II) is ethylene / (ethylene + propylene) =
It is 10 to 100% by weight, preferably 20 to 70% by weight, and the polymerization amount is 5 to 40% by weight based on the final propylene / ethylene block copolymer. Also ethylene,
Other α-olefins, non-conjugated dienes and the like may be used in combination with propylene. MFR (i) of the polymer obtained in the polymerization step (I) and M of the polymer obtained in the polymerization step (II)
The relationship of FR (ii) is preferably 3 ≦ Log (MFR (i) / MFR (ii)) ≦ 7, and more preferably 4 ≦ Log (MFR (i) / MFR (ii)) ≦ 6. MFR (i) is the measured value of only the polymer in the polymerization step (I), and MFR (ii) is the MF after completion of the second stage.
The following equations (2) and (3) based on the measured R value {MFR (i + ii)}, the polymer fraction (W1) in the polymerization step (I) and the polymer fraction (W2) in the polymerization step (II) It is a calculated value by. LogMFR (T) = W1 × LogMFR (i) + W2
× LogMFR (ii) W1 + W2 = 1 When Log (MFR (i) / MFR (ii)) <3,
The obtained polymer is inferior in terms of low temperature impact strength, tensile elongation and the like, which is not preferable. Further, a large amount of a polymer soluble in the polymerization solvent is generated, which is not preferable in terms of economy and plant operability. In addition, Log (MFR (i) / M
When FR (ii))> 7, the yield of the polymer per unit catalyst becomes small, which is not practical.

Incidentally, analysis of various physical properties according to Examples described later,
The measurement methods and the like are shown below.・ MFR; ASTM D-1238 (unit: g / 10 m
in) 230 ° C, 2.16 kg load-Ethylene content; by infrared absorption spectroscopy. (Unit: wt%)-Polymerization ratio (W1, of the polymerization step (I) and the polymerization step (II)
W2); A copolymer in which the reaction amount ratio of ethylene / propylene is changed is prepared in advance, and this is used as a standard sample, and a calibration curve is prepared by infrared absorption spectrum to obtain the reaction amount ratio of ethylene / propylene in the polymerization step (II). Furthermore, it was calculated from the ethylene content in the total polymer. (Weight / weight) ・ Flexural modulus; based on JIS K7203 (unit: MPa). -Tensile strength; conforms to JIS K7113 (unit: MPa). -Tensile elongation; conforms to JIS K7113 (unit:%).・ HDT; conforms to JIS K7207 (unit: ° C). -Izod impact strength (II); conforms to JIS K7110 (unit: J / m). As described above, the present invention is a production method capable of achieving an effect significantly exceeding the known art by using specific polymerization conditions, and the present invention will be described in more detail with reference to Examples. Is not limited to this.

Example 1 (Catalyst Preparation-Solid Titanium Catalyst Component Preparation) 150 g of magnesium ethoxide, 275 ml of 2-ethylhexyl alcohol and 300 ml of a mixture of toluene at 93 ° C. under a carbon dioxide atmosphere of 0.3 MPa. After stirring for 3 hours, 400 ml of toluene and 400
ml n-decane was added. Hereinafter this solution is referred to as a magnesium carbonate solution. 100 ml of toluene, 30 ml
Chlorobenzene, 9 ml tetraethoxysilane,
8.5 ml of titanium tetrachloride and 100 ml of Isopar G (isoparaffin hydrocarbon having an average carbon number of 10, boiling point 156 to 176 ° C.) were stirred at 30 ° C. for 5 minutes, and 50 ml of the magnesium carbonate was added. After stirring this for 5 minutes, 22 ml of tetrahydrofuran was added,
The mixture was stirred at 0 ° C for 1 hour. After the stirring was stopped and the supernatant was removed, the produced solid was washed with 50 ml of toluene.
100 ml of chlorobenzene and 100 m were added to the obtained solid.
l of titanium tetrachloride was added, and the mixture was stirred at 135 ° C. for 1 hour. After stopping the stirring and removing the supernatant, 250 ml of chlorobenzene, 100 ml of titanium tetrachloride and 2.1 ml of
1. Add ml of di-n-butyl phthalate and add 1.
Stir for 5 hours. After removing the supernatant, the solid was washed successively with 600 ml of toluene, 800 ml of Isopar G, and 400 ml of hexane to collect a solid catalyst component. The composition of this solid catalyst component is 2.3% by weight titanium and 55% chlorine.
% By weight, 17% by weight of magnesium and di-n-phthalate
Butyl was 7.5% by weight.

Preparation of pre-activated catalyst After replacing a stainless steel reactor with an inclined blade with an internal volume of 50 L with nitrogen gas, 40 L of n-hexane was charged, and 75 g of the above solid product and 13 g of triethylaluminum were added at room temperature. After that, 100 g of propylene was supplied over 120 minutes to remove unreacted propylene and n-hexane under reduced pressure to obtain 150 g of preactivated catalyst.

Polymerization Step (I) Into a nitrogen-substituted stainless steel polymerization vessel having an internal volume of 500 L and equipped with a turbine type stirring blade, 250 L of n-hexane, 89 g of triethylaluminum and 69 g of di-i-propyldimethoxysilane as an organosilicon compound were charged, Then, 15 g of the pre-activated catalyst was added and the temperature inside the vessel was adjusted to 70
After the temperature was raised to 0 ° C., propylene and hydrogen were supplied to carry out the first-stage polymerization for 1 hour while maintaining the total pressure at 0.8 MPa and the hydrogen / propylene concentration ratio in the gas phase portion at 0.24. The supply of propylene was stopped, the temperature inside the vessel was cooled to 30 ° C., and hydrogen and unreacted propylene were discharged. Then, a part of the polymerized slurry was taken out, MFR was measured, and M in the polymer was measured.
An inductively coupled plasma emission spectroscopic analysis (ICP method) of g was performed to determine the polymer yield per unit weight of the catalyst. After the temperature inside the vessel was raised to 70 ° C., propylene and hydrogen were supplied to maintain the total pressure at 1.0 MPa and the hydrogen / propylene concentration ratio in the gas phase portion at 0.24 for 1 hour in the second stage. After the polymerization was completed, the propylene supply was stopped and the temperature inside the vessel was reduced to 3
After cooling to 0 ° C., hydrogen and unreacted propylene were released. Then, a part of the polymerized slurry was extracted, the MFR was measured, and the Mg content in the polymer was determined by the ICP method to determine the second-stage polymer yield. Then the above 1
The yield value of the first stage was used to determine the ratio of the polymerization amounts of the first stage and the second stage. Furthermore, logMFR = a × logMFR + (1-a) × log
MFR ₂ a: 1st stage polymerization ratio, MFR: 2nd stage final extraction product MFR MFR ₁ , MFR ₂ : 1st stage and 2nd stage MFR Substitute the values of MFR ₁ and MFR for the 2nd stage Stage MFR
I asked for ₂ . Then, after the temperature inside the vessel was raised to 70 ° C., propylene and hydrogen were supplied to maintain the total pressure at 1.2 MPa and the hydrogen / propylene concentration ratio in the gas phase portion at 24% for 1 hour in the third stage. After carrying out the polymerization, the supply of propylene was stopped,
The temperature inside the vessel was cooled to 30 ° C., and hydrogen and unreacted propylene were discharged. Then, pull out a part of the polymerization slurry,
MFR is measured and the Mg content in the polymer is measured by IC
It was determined by the P method, and the ratio of the third stage polymerization was determined. Furthermore, logMFR = a × logMFR ₁ + b × logMFR
₂ + c × log MFR ₃ a + b + c = 1 a: 1st stage polymerization ratio, b: 2nd stage polymerization ratio, c: 3rd stage polymerization ratio MFR: 3rd stage end extracted product MFR MFR ₁ , MFR ₂ , MFR ₃ : 1st stage, 2nd stage,
The values of MFR ₁ , MFR ₂ and MFR were substituted into the third stage MFR to obtain the third stage MFR ₃ .

Polymerization step (2) After the internal temperature was raised to 60 ° C., the ethylene feed ratio was changed to 35
Ethylene and propylene were continuously supplied for 2 hours so that the weight% was adjusted. The total supply of ethylene was 4.5 kg. During the polymerization, hydrogen was supplied so that the gas phase hydrogen concentration was 1 mol%. After the polymerization for 2 hours, the supply of ethylene and propylene was stopped, the temperature inside the vessel was cooled to 30 ° C., and then unreacted ethylene and propylene were discharged. Then, 50 L of methanol was supplied into the polymerization vessel, and the temperature inside the vessel was raised to 60 ° C. After 30 minutes, 0.5 L of caustic soda water of 20% by weight was further added and stirred for 20 minutes, and 100 L of pure water was added.
The internal temperature was cooled to 30 ° C. After extracting the water tank, 300 L of pure water was further added, and the mixture was washed with stirring water for 10 minutes, and then the water tank was extracted. Then, the hexane slurry was extracted, filtered, and dried. The propylene / ethylene block copolymer obtained was analyzed, and the values are shown in Table 1.

Manufacture of injection-molded product To 3.0 kg of the product powder obtained above, 0.003 kg of a phenolic heat stabilizer, calcium stearate 0.
003 kg was added, and the mixture was mixed for 10 minutes at room temperature with a high-speed stirring mixer (Note Henschel mixer, trade name), and the mixture was granulated using an extruder with a screw diameter of 40 mm.
Then, the granulated product was melted at a resin temperature of 230 ° C. by an injection molding machine.
A JIS type test piece was prepared at a mold temperature of 50 ° C., and the humidity of the test piece was 50%.
Time adjusted. Then, the physical property values were measured as shown in Table 1 below.

Examples 2 and 3 and Comparative Examples 1 and 2 In the polymerization step (I), the amounts of di-i-propyldimethoxysilane added were 27.4 g, 13.7 g, 6.9 g and 172 g.
Table 1 shows the results obtained in the same manner as in Example 1 except that When the molar ratio (B / C) of the organosilicon compound (C) to the organoaluminum compound (B) is larger than that of the present invention, the rigidity of the obtained molded article is poor, and when it is small, the yield of the polymer per unit catalyst is low. It deteriorates and is not practical.

[0024]

[Table 1]

Example 4 In the polymerization step (I), the hydrogen / propylene concentration ratios in the gas phase portions of the first, second and third stages were 0.3, 0.23, respectively.
Table 2 shows the results obtained in the same manner as in Example 2 except that the content was changed to 0.16.

Example 5 In the polymerization step (I), the hydrogen / propylene concentration ratio of the gas phase portions of the first and second stages was changed to 0.22, and the polymerization time of each stage was changed to 1.5 hours. Table 2 shows the results obtained in the same manner as in Example 4 except that the third-stage polymerization was omitted.

Comparative Example 3 In the polymerization step (I), the hydrogen / propylene concentration ratios of the gas phase portions of the first and second stages were 0.21 and 0.23, respectively, and the polymerization time of each stage was 1.5 hours. Table 2 shows the results obtained in the same manner as in Example 5 except that the above was changed. log (MFR
Since the value of (h) / MFR (1)) is smaller than that of the present invention,
The rigidity of the molded product is inferior to that of the product of the present invention.

Comparative Example 4 In the polymerization step (I), the hydrogen / propylene concentration ratio in the first step was changed to 0.18, the polymerization time was changed to 3 hours, and the second and third steps were omitted. Table 2 shows the results obtained in the same manner as in Example 4. The rigidity of the molded product is inferior to that of the present invention.

[0029]

[Table 2]

Comparative Example 5 In the polymerization step (I), the hydrogen / propylene concentration ratios of the gas phase portions of the first, second and third stages were 0.45 and 0.23, respectively.
Table 2 shows the results obtained in the same manner as in Example 4 except that the value was changed to 0.10. log (MFR (h) / MFR (1))
Value is larger than that of the present invention, the impact resistance of the molded product is poor.

Example 6 In the polymerization step (I), the hydrogen / propylene concentration ratio of the first, second and third vapor phase parts was set to 0.35, and the hydrogen concentration in the vapor phase of the polymerization step (II) was set to 0. Table 3 shows the results obtained in the same manner as in Example 2 except that the content was changed to 0.2 mol%.

Example 7 In the polymerization step (I), the hydrogen / propylene concentration ratio in the first, second, and third vapor phase portions was set to 0.20, and the hydrogen concentration in the vapor phase in the polymerization step (II) was set to 3 Table 3 shows the results obtained in the same manner as in Example 2 except that the content was changed to mol%.

Comparative Example 6 In the polymerization step (I), the hydrogen / propylene concentration ratio in the first, second, and third gas phase portions was set to 0.60, and the gas phase hydrogen concentration in the polymerization step (II) was changed. Table 3 shows the results obtained in the same manner as in Example 2 except that the content was changed to 0.05 mol%. MFR ratio of polymerization step (I) and polymerization step (II) (log (MFR (i) / M
Since FR (ii)) is larger than that of the present invention, the impact resistance is inferior and the yield of the polymer per unit catalyst is reduced, which is not practical.

Comparative Example 7 In the polymerization step (I), the hydrogen / propylene concentration ratios of the first, second and third gas phase portions were respectively set to 0.18, and the gas phase hydrogen concentration in the polymerization step (II) was changed. Table 3 shows the results obtained in the same manner as in Example 2 except that the content was changed to 10 mol%. MFR ratio of polymerization step (I) and polymerization step (II) (log (MFR
Since (i) / MFR (ii)) is smaller than that of the present invention, rigidity, impact resistance and tensile elongation are inferior to those of the present invention, and the amount of a polymer soluble in a polymerization solvent is large, which is not preferable.

[0035]

[Table 3]

Example 8 In the polymerization step (I), the hydrogen / propylene concentration ratio in the gas phase portions of the first, second and third steps was set to 0.08, and the gas phase hydrogen concentration in the polymerization step (II) was changed to Table 4 shows the results obtained in the same manner as in Example 3 except that the total amount of ethylene fed was changed to 0.5 mol% and 2 kg.

Example 9 In the polymerization step (I), the hydrogen / propylene concentration ratio of the first, second and third vapor phase parts was set to 0.17, and the gas phase hydrogen concentration in the polymerization step (II) was changed to Table 4 shows the results obtained in the same manner as in Example 3 except that the amount of ethylene fed was changed to 0.5% by weight, the amount of ethylene fed was changed to 65% by weight, and the total amount of ethylene fed was changed to 7 kg.

Comparative Example 8 Table 4 shows the results obtained in the same manner as in Example 9 except that ethylbenzoate was used as an electron donor in the preparation of the solid catalyst component (A). The rigidity and impact resistance are significantly inferior to those of the present invention.

Comparative Example 9 As the solid catalyst component (A), the reduced catalyst described in the examples of JP-A-58-201816, as the organoaluminum compound (B), diethyl aluminum chloride, and the organosilicon compound (C) were used. Table 4 shows the results obtained in the same manner as in Example 9 except that methyl p-toluate was used instead of). The rigidity and impact resistance are inferior to those of the present invention, and the yield of the polymer per catalyst unit is low.

[0040]

[Table 4]

Examples 10 to 14 Except that t-butyltrimethoxysilane, t-butyltriethoxysilane, i-butyltrimethoxysilane, cyclohexyltrimethoxysilane and di-i-butyldimethoxysilane were used as the organosilicon compound. The results obtained in the same manner as in Example 2 are shown in Table 5.

[0042]

[Table 5]

Comparative Examples 10 to 13 Table 6 shows results obtained in the same manner as in Example 2 except that methyl p-toluate, triethylamine, acetophenone and diethylene glycol dimethyl ether were used as electron donors instead of the organosilicon compound. The rigidity is inferior to that of the present invention and the amount of the polymer soluble in the polymerization solvent is large, which is not preferable.

[0044]

[Table 6]

[Brief description of drawings]

FIG. 1 is a flow sheet showing manufacturing steps of the method of the present invention.

Claims (2)

[Claims] 1. A solid catalyst component (A) containing titanium, magnesium, halogen and a polycarboxylic acid ester as essential components, an organoaluminum compound (B) and a general formula R ⁴ _x R ⁵ _y Si (OR ⁶ ) _z. (In the formula, R ⁴ and R ⁶ represent a hydrocarbon group, R ⁵ represents a hydrocarbon group or a hydrocarbon group containing a hetero atom, and x + y + z = 4,0 ≦ x ≦ 2,1 ≦ y ≦
3, 1 ≦ z ≦ 3. 2) is used as the first step by using a catalyst system in which an organosilicon compound (C) represented by
Using a polymerization vessel of more than one tank in series, ethylene / (ethylene +
Propylene) = 0 to 5% by weight of a monomer is supplied to carry out a polymerization step (I) mainly composed of propylene to produce 60 to 95% of the total amount of polymerization, and a second or more polymerization vessel as a second stage. And ethylene / (ethylene + propylene) = 1
A propylene / ethylene block copolymer, characterized in that the polymerization step (II) containing a relatively large amount of ethylene is carried out to prepare 5 to 40% by weight of the total polymerization amount by supplying 0 to 100% by weight of a monomer. In the production method, the maximum value (hereinafter referred to as MFR (h)) and the minimum value (hereinafter referred to as MFR) of the melt flow rate of the polymer obtained in each tank of the polymerization step (I)
(Referred to as (l)) has a relationship of 0.1 ≦ Log (MFR (h) / MFR (l)) ≦ 1 and a polymer obtained in the polymerization step (I) mainly containing propylene. The melt index (hereinafter referred to as MFR (i)) and the melt index of the polymer obtained in the polymerization step (II) containing a relatively large amount of ethylene (hereinafter referred to as MFR (ii)) are 3 ≦ Log (MFR (i)). / MFR (ii)) ≦ 7, a method for producing a high-rigidity propylene / ethylene block copolymer, which is characterized in that it is produced. 2. The production method according to claim 1, wherein the molar ratio of the organosilicon compound (C) and the organoaluminum compound (B) is (B) / (C) = 1 to 15.