JPS63251411A - Continuous preparation of ethylene-propylene copolymer of high melt viscoelasticity - Google Patents

Abstract

PURPOSE:To prepare the title copolymer which is suitable for sheet and excellent in impact strength, by feeding the total amounts of a catalyst and hydrogen both into the first tank of polymn. vessels connected in series and drawing gases continuously from the gaseous portion of the second and subsequent polymn. tanks. CONSTITUTION:The title copolymer is prepared by the following continuous procedures. Out of polymn. vessels consisting of at least 3 tanks connected in series, the first and the second tanks are charged with monomers in which the ratio by wt. of ethylene to ethylene + propylene is 0-5%, so as to carry out a continuous polymn. process I chiefly for propylene, and then the third and subsequent tanks are charged with monomers in which the ratio by wt. of ethylene to ethylene + propylene is 10-100%, so as to carry out a continuous polymn. process II chiefly for ethylene in majority. A catalyst and gaseous hydrogen as an MW modifier are both to be fed in total amounts into the first tank, and gases are drawn continuously from the gaseous portion of the second and subsequent polymn. tanks. The quantity of the gases drawn out should be 0.5-10V1 per hour at 0 deg.C and 0Kg/cm<2>G, providing that the vol. of the polymn. vessel is V1, and the quantity of polymn. in the polymn. process I be 60-95wt.% of the total quantity of polymn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a continuous process for producing a high melt viscoelastic ethylene-propylene copolymer. More specifically, the present invention performs the polymerization step (i) mainly consisting of propylene in the first to second tanks of three or more polymerization vessels connected in series, and relatively ethylene is not produced in the third tank and subsequent tanks. It relates to the production method in which a large amount of polymerization is used.

The copolymers obtained by the method of the invention have a better impact strength than equivalent products obtained by known methods and are suitable for post-processed sheets, blow molding and injection molding.

[Conventional technology]

Sheets manufactured by processing and molding known general-purpose polypropylene have the following drawbacks when used for post-processing. When forming for secondary processing, the sheet sags quickly, the width of the processing conditions is narrow, and the forming efficiency is poor.
The disadvantages include that the thickness of the post-processed product tends to be uneven and that wrinkles are likely to occur. For this reason, only small molded products can be manufactured.

On the other hand, when processing known general-purpose polypropylene by blow molding, there are the following problems. That is, (1) the parison sags significantly during molding, resulting in uneven wall thickness of the molded product;

For this reason, the blow molding method can only be applied to small molded products.■ If high molecular weight polypropylene is used to prevent the above-mentioned sagging, the flowability of the melt will be poor, the load during molding will increase, and energy loss will occur. Not only does this increase the risk of causing mechanical problems, but the surface of the actually molded product becomes noticeably rough, and its commercial value is lost.

In order to improve the above-mentioned sheet moldability and blow moldability regarding the use of polypropylene, for example, Japanese Patent Publication No. 47-80
In No. 814 and JP-A-50-8848, low density polyethylene and the like are mixed with polypropylene. However, molded products using such mixtures are prone to rough skin, and to prevent rough skin, strong kneading is required during melting, making it difficult to implement these inventions in terms of kneader selection and power consumption. be restricted. In addition, the invented product also has the problem of reduced rigidity. Also, JP-A-53-! No. 111954,
No. 57-185338, No. 57-187337, No. 5B-7438, etc. propose a method of kneading polypropylenes having different molecular weights using a granulator or the like. However, molded products made from the mixtures according to these inventions are more likely to have rough skin than those made from the above-mentioned low-density polyethylene mixtures, and the implementation of these inventions is limited by the selection of kneading methods and molecular weight differences. Ru.

In order to solve the above-mentioned problems related to the moldability of general-purpose polypropylene, many methods have been proposed for broadening the molecular weight distribution of the target product using multi-stage polymerization methods. for example,
JP-A-57-185304, JP-A No. 57-190008
No. 58-7405, No. 58-7408, No. 59-172507, etc. According to the examples of these inventions, most of them use batch polymerization to produce polypropylene with different molecular weights in multiple stages.
Since so-called idle time occurs, which is different from the polymerization reaction itself, commercial production methods have the disadvantage of low productivity per unit equipment.

Furthermore, in the inventions of JP-A-57-185304 and subsequent patents, continuous polymerization methods are also mentioned, and when the stepwise production order involves the combination of (a) polymeric prize → low molecular weight product, It is preferable as a process because the required molecular weight difference can be achieved simply by adding hydrogen at the latter stage of multi-stage polymerization.On the other hand, in the case of (b) combination of low molecular weight product → high molecular weight product, the low molecular weight polypropylene After manufacturing the polymeric product, it is necessary to remove unnecessary hydrogen from the tank holding the polymerization reaction mixture by reducing pressure or degassing the tank before manufacturing the polymer prize. It is stated that the processability is inferior.

However, according to the inventor's follow-up study, in the case of manufacturing in the order of polymer premiums → low molecular weight products, which was described as preferable in the prior art, the melt flow rate (hereinafter referred to as MFR) value of the high molecular weight portion If the viscosity is too low, measurement becomes difficult or impossible, which poses a problem in operational control. (not in a typical way).

Furthermore, polypropylene produced in multiple stages in the order of high molecular weight → low molecular weight has an abnormally large difference in MFR value between the MFR value of the powder before granulation and the pellet obtained by granulation (note: It was found that there were problems in controlling the molecular weight difference between each stage as a multistage polymerization method and in controlling the MFR value of the product.

On the other hand, although crystalline polypropylene has excellent physical properties such as rigidity and heat resistance, it has the problem of low impact strength, particularly at low temperatures, which limits its practical range. In order to improve this drawback, many methods have been proposed in which propylene is block copolymerized with ethylene or other α-olefins. For example, JP-A-50
-142852, 52-8094, 57-34
Many proposals have been made, including No. 112. However, these
After polymerization 1 mainly consisting of propylene, polymerization 2 using a monomer containing relatively large amounts of ethylene except for hydrogen is performed, and at this time, measures are taken to widen the molecular weight distribution.

In general, when a multi-stage continuous polymerization method is adopted in the block copolymerization method, the residence time of each catalyst particle in each stage has a distribution (note: it is considered to be close to a complete mixing tank distribution), so the product has a polypropylene portion. The content ratio of polyethylene and polyethylene parts (note: parts containing a relatively large amount of ethylene) becomes a collection of polymer particles that differ from time to time, and defects in quality arise due to this non-uniformity.

In particular, in the method of the present invention, which will be described in detail later, since a molecular weight difference is imparted to each stage in the multi-stage polymerization step (i) mainly using propylene, if the known technology is adopted as is, the polymerization The molecular weight difference between particles is larger than that in ordinary block copolymerization, and problems due to non-uniformity can become more significant.

A number of methods have been proposed to improve the problems of multi-stage continuous polymerization methods using known techniques such as double-stage polymerization. For example, JP-A-58-48918, JP-A-55-11E1718, JP-A-5
No. 8-H215 etc. propose a method in which the slurry after leaving the polypropylene polymerization section (polymerization step 1) is classified using a cyclone, and the fine particles are returned to the polypropylene polymerization section, but the polymer particle size Since the classification by the method does not necessarily match the residence time distribution, its effectiveness was insufficient. JP-A-57-185718, JP-A No. 58-29811
In No. 1, etc., a method is described in which the catalyst is intermittently supplied to the polymerization vessel and the slurry is withdrawn from the polymerization vessel in order to reduce the portion of the catalyst that enters the polyethylene polymerization section (polymerization step 2) while the residence time is short. Some methods have also been proposed, but these methods have the problem that the polymerization reaction becomes unstable.

Furthermore, as in embodiment (8) of the present invention described later, by treating the slurry leaving the polypropylene polymerization section with an electron-donating compound, etc., the residence time is short and the catalyst particles are selectively discharged. Several methods for inactivation have also been proposed.

For example, JP-A-57-145115 and JP-A-57-145-
No. 115417 proposes various electron-donating compounds, but the compounds used in the examples were insufficient to achieve the object of the present invention, which will be described later.

In order to solve the above problem, the present inventors proposed the invention of Japanese Patent Application No. 80-283728 based on the results of various studies. However, the above method has problems in that the process is rather complicated, such as requiring four or more polymerization vessels, and there being a limit of M on the reaction amount ratio and polymerization conditions in each polymerization vessel.

[Purpose of the invention]

In view of the above-mentioned problems in the known and prior art related to the multistage continuous polymerization method of propylene-ethylene block copolymers, the present inventor conducted research to find a polymerization method that improves these problems, and as a result: Using three or more polymerization vessels connected in series, the first two or more polymerization vessels carry out polymerization mainly consisting of propylene (ethylene content in feeder polymer θ ~ 5% by weight), and then polymerize the remaining polymer. In a polymerization vessel with one or more tanks,
Polymerization containing a relatively large amount of ethylene is carried out (ethylene content in the monomers supplied is 10 to 100% by weight), and the entire amounts of the catalyst and hydrogen used as a molecular weight regulator are supplied to the first tank, and the catalyst and hydrogen are In the continuous polymerization step (i) mainly consisting of propylene, hydrogen (excluding the amount consumed during the process) is carried out in such a way that it is sequentially transferred together with the reaction mixture (slurry) to the second tank or later. By continuously extracting gas from the gas phase of the polymerizer from the second tank onward, the molecular weight of the polymer produced in each polymerizer can be arbitrarily adjusted at a practical level without the need for special degassing equipment. They discovered that it is possible to do so, and completed the present invention.

As is clear from the above description, the purpose of the present invention is to stably produce ethylene-propylene block copolymerization that has good physical properties for sheets, blow molding, and injection molding, and is capable of producing large molded products. It is an object of the present invention to provide a continuous polymerization method for a high melt viscoelastic ethylene block copolymer that can be produced in the following manner. Another object is to provide a coelectric composite produced by the method, and other objects will become clear from the description below.

[Structure and effects of the invention]

The present invention has the following main configuration (1) and embodiment configurations (2) to (4).

(1) In a method for continuously producing ethylene-propylene copolymer using a Ziegler-Natsuta type catalyst, a. Three or more polymerization vessels connected in series are used, initially including tanks 1 and 2. A continuous polymerization step (i) mainly consisting of propylene is carried out by supplying monomers having a weight ratio of ethylene and ethylene + propylene of 0 to 5% by weight in the feeder to a polymerization vessel having two or more tanks, and then A monomer having a weight ratio of ethylene and ethylene + propylene in the supplied monomer of 10 to 100% by weight is supplied to one or more polymerization vessels not used in the step (i), so that the amount of ethylene is relatively lower than that in the previous step. Continuous polymerization step (i) containing a large amount is carried out, b. The entire amount of the catalyst to be used is supplied to the first tank, and the supplied catalyst is sequentially passed through the second tank and thereafter together with the polymerization reaction mixture, and the same After each stage of polymerization, the polymer polymerized in the vessel is formed on the catalyst solid, and then discharged from the final vessel, and c.
In the continuous polymerization step (1) mainly using propylene, hydrogen gas is used as a molecular weight regulator, and the entire amount of hydrogen gas is supplied to the first tank, and from the second tank onwards, it is supplied to each pre-tank. The residue consumed in step 1 is transferred together with the polymerization reaction mixture (slurry), and 2. In the continuous polymerization step (1) mainly using propylene, gas is continuously extracted from the gas phase of the polymerization vessel from the second tank onwards. , when the volume of the gas is V, and the volume of the polymerization vessel is V,
0℃, 0.5V per hour in Okg/crrfG
A method for continuously producing a high melt viscoelastic ethylene-propylene copolymer, characterized in that the IOV is 1 and the amount of polymerization in the polymerization step (i) is 60 to 95% by weight of the total amount of polymerization.

(2) In the continuous polymerization step (i) mainly containing propylene, the molecular weight of the polymer produced in the first and last polymerization vessels is such that the MFR value is within the range of the following formula (1). Continuous manufacturing method described in section 1).

However, MFI? +: MF of the polymer produced in the i-th polymerization vessel
RMFRt: Continuous polymerization process mainly using propylene (
i) MFR of the polymer produced in the final polymerization tank (
3) In the continuous polymerization step (i) mainly containing propylene, the gas extracted from the gas phase of each polymerization vessel from the second onward is
The production method according to item (1) above, characterized in that the method is recycled to a second polymerization vessel for reuse.

(4) Organoaluminum compound (B) combined with the titanium-containing solid component (A) constituting the Ziegler-Natsuta catalyst
) as the general formula AI rt )'v −m (in the formula R
Q represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a halogen atom, and m represents a number of 3≧m>1.5), and the continuous polymerization step (i) It is carried out in the presence of an active solvent or liquid propylene, and glycol ethers (C) are added to the polymerization reaction mixture (slurry) after the completion of this step, with respect to the titanium component in (A), (C:) / ( A) Ti=0.01-1.0 (
The continuous production method according to item (1) above, wherein the continuous polymerization step (11) is performed by continuously adding the polymer at a concentration of mol/atom).

The structure and effects of the present invention will be explained in detail.

The catalyst used in the present invention may be a so-called Chiguchi-Natsuta catalyst and is not particularly limited, but preferably a catalyst based on a combination of a titanium compound and an organoaluminum compound is used.

The titanium compound may be a titanium trichloride composition obtained by reducing titanium tetrachloride with hydrogen or metal aluminum or the like, or a titanium trichloride composition further ground and activated using a ball mill, vibration mill, etc.; The activated product is treated with an electron donor, titanium tetrachloride is reduced with an organoaluminum compound, and then subjected to various treatments (for example, titanium trichloride compositions are subjected to crystal transition by heating in titanium tetrachloride, electron donating titanium trichloride compositions obtained by highly activated titanium trichloride treated with a compound or an electron-accepting compound, and so-called supported type titanium tetrachloride obtained by supporting titanium tetrachloride on a carrier such as magnesium chloride. Catalysts that are generally used for stereoregular polymerization of propylene can be suitably used.

As the organoaluminum compound used in the present invention, a compound represented by the general formula AIRnR'rtXa -<nm can be preferably used. In the formula, R and R' represent a hydrocarbon group such as an alkyl group or an aryl group, and X represents fluorine,
Represents halogens of chlorine, bromine and nitrogen, n and n'' are 0
<nun'< 3 represents an arbitrary number. Specific examples thereof include trialkylaluminums and dialkylaluminum monohalides, and these can be used alone or in combination of two or more. Furthermore, an electron donor commonly used as the third component of the catalyst can be used in combination with the titanium compound and organoaluminum compound.

As the polymerization method, slurry polymerization using a hydrocarbon such as propane, hexane, heptane, octane, benzene, or toluene as a solvent, or bulk polymerization using propylene as a solvent can be used.

A seed type polymerization vessel is preferably used, and in the polymerization step (1) mainly using propylene, two or more polymerization vessels are connected in series, and the polymerization reaction mixture (slurry) is transferred between the polymerization vessels. A part of the slurry (liquid phase) is continuously extracted and continuously transferred to the next polymerization vessel.

The polymerization step (ii) containing a relatively large amount of ethylene includes a first tank that continuously receives the polymerization reaction mixture from the final polymerization vessel of the first step, preferably one or more seed-type polymerization vessels. Continuous polymerization is carried out by supplying ethylene and propylene at a predetermined ratio.

In the method of the present invention, the catalyst used is the above-mentioned first catalyst.
Throughout the second step, it is supplied only to the polymerizer in the first tank. In this way, the supplied catalyst solid passes through the polymerization vessels in sequence, such as the second tank and the third tank, together with other polymerization reaction mixtures, and the HR, the polymer formed in each polymerization vessel on the solid particles. The polymer is removed from the final polymerization vessel while still covered.

If a new catalyst is supplied from the second tank onwards, a polymer with a significantly different MFR from that from the first tank will be produced on the solid particles of the catalyst, so granulation after product collection will be required. It is difficult to mix them uniformly depending on the process, and molded products made from such products are undesirable because they cause defects in product appearance such as fish eyes.

In the method of the invention, hydrogen is used as a molecular weight regulator. As with the catalyst described above, the hydrogen is supplied only to the first tank polymerizer throughout the entire process. The first tank may be supplied to either the gas phase or the liquid phase within the tank.

However, hydrogen is supplied from each pre-tank to the second tank and subsequent tanks in a form dissolved in the above-mentioned polymerization reaction mixture, that is, in a solution state. Therefore, when supplying hydrogen to the liquid phase (polymerization reaction mixture) in the first tank, care must be taken to prevent undissolved hydrogen from being transferred to the second tank as bubbles. If the hydrogen that has been engulfed in the liquid phase in the form of bubbles is sent to the next tank (there is a possibility that this may occur depending on the stirring conditions in the second tank or later), degassing will occur in the second tank or later. The amount of gas extracted during this process is larger than when hydrogen bubbles are not present in the liquid phase, and the extraction efficiency decreases. The gas extracted from the gas phase of the polymerization reactor is 0°O, Okg/Cm'G per hour, when the volume of the polymerization reactor to be extracted is vl.
．． 5V 1" IOV 1 is preferable. A method of continuously extracting gas using a control valve to maintain the hydrogen concentration in the gas phase at the target concentration while measuring the hydrogen concentration in the gas phase using process gas chromatography, etc. is preferred.

Depending on the degree of hydrogen extraction, the MFR of the polymer produced in the tank can be reduced to a preferable degree compared to the case where the extraction is not performed. All or part of the extracted gas can be recycled to the first tank.

In the method of the present invention, propylene, ethylene, and a solvent are supplied to each polymerization tank as necessary.

The purpose of replenishing the solvent is to appropriately maintain the slurry concentration in each polymerization tank in accordance with the increasing amount of polymer. By carrying out the polymerization step (i) of the present invention as described above, the molecular weight of the polymers produced in each type increases stepwise from the first tank to the second tank and from the second tank to the third tank. , a sufficient molecular weight difference can be imparted as a whole.

The polymerization pressure of the propylene-based polymerization step (i) of the present invention is not limited, but is usually normal pressure to 50 kg/cm'G.
is used. The polymerization pressures of the polymerization vessels connected in series according to the method of the present invention may be the same or different.

The polymerization temperature carried out in the continuous polymerization step (i) mainly consisting of propylene of the present invention is not limited, but is 20 to 10
0°C, preferably 40-80°C.

In the method of the present invention, the average residence time of the reaction mixture in each polymerization vessel connected in series is not limited, but is usually 3.
Executed from 0 to IO time. Furthermore, the object of the present invention can be easily achieved by selecting and carrying out the various polymerization conditions described above, ie, pressure, temperature, residence time, etc., depending on the quality of the desired polypropylene, the catalyst used, etc.

Transfer of slurry between polymerization vessels connected in series is
Conventional pump transportation and differential pressure transportation methods can be used, and there are no special restrictions.

The MFR of the ethylene-propylene copolymer according to the present invention obtained as described above and through the subsequent polymerization step (iI) according to the method of the present invention is usually 0. O1~1
00, but especially for sheet molding and blow molding, the MFR value is 0.05 to 10. Preferably 0.1
0 to 5.0 is used.

Incidentally, when expressed as an MFR value, the molecular weight difference between the polypropylenes produced in each polymerization vessel of the polymerization step (i) connected in series is preferably within the range of the following formula [11].

Tagushi, MFRf; MFR of the polymer produced in the f-th polymerization vessel MFRt; continuous polymerization process (i) mainly consisting of propylene
MFR of the polymer produced in the final polymerization vessel in If the value on the left side of the above formula [1] is less than 2.0, the high melt viscoelasticity of the polymer targeted by the present invention is likely to be insufficient, which is undesirable. .

The composition of the monomers supplied to the polymerization step (i) of the present invention is as follows: ethylene (C;) + propylene (c-,) frit%. If the amount of ethylene used exceeds 5% by weight, the physical properties of the final copolymer, such as rigidity and heat resistance, which are characteristics of polypropylene, tend to deteriorate, which is undesirable. Further, as the monomer, 1-butene, 4-methylpentene-1, styrene, or non-conjugated dienes, etc. can be added in an amount of 0 to 10% by weight based on the propylene, independently of the ethylene.

The ratio of the polymerization amount in the polymerization step (i) of the present invention is 60 to 95% by weight, preferably 75 to 80% by weight, based on the ethylene-propylene copolymer that is the final product. Polymerization in the polymerization step (i) exceeding the above lower limit will result in a decrease in the rigidity of the product block copolymer, and polymerization below the above lower limit will insufficiently improve the low-temperature impact strength of the copolymer. It can be selected within the above range depending on the quality objective.

The effluent slurry after the completion of the polymerization step (i) of the present invention is continuously transferred to the first polymerization vessel of the polymerization step (ii), and the slurry is continuously transferred to the first polymerization vessel of the polymerization step (11) containing a relatively large amount of ethylene.
>I do.

In the polymerization step (it), at least twice as much ethylene (10% by weight) as in the polymerization step (1) is used. In the polymerization step (-1), it is not essential to use two or more polymerization vessels, but if the amount of polymerization in the step (11) is relatively large, such as 20 to 40% by weight, If more than one polymerizer is used, it is possible to balance the amount of polymer produced between each polymerizer.

In addition, in the polymerization step (11), the ethylene concentration in the supplied monomer is significantly different from that in the step (1), so the polymerization step (
The slurry discharged from i) can be once received into a drop-pressure tank, degassed (note, to remove dissolved propylene, ethylene, and hydrogen), and then fed to the polymerization vessel for one polymerization step (it). The polymerization step (tD) is carried out in the same manner as in the polymerization step (1), except that monomers at a predetermined ethylene/ethylene+propylene weight ratio and required amounts of hydrogen and solvent are supplied.

In a preferred embodiment of the method of the invention, this polymerization step (
In step 11), a specific glycol ether (hereinafter sometimes referred to as additive C) is added as the third catalyst component.

The purpose of this addition is to directly reduce the activity of the added catalyst to a considerable extent, but in reality, it selectively inactivates the short-pass catalyst (highly active catalyst) and The process consists in homogenizing the polymer produced in the two steps.

Examples of the glycol ethers include ethylene glycol monoalkyl ether, ethylene glycol dialkyl ether, propylene glycol monoalkyl ether, and propylene glycol sialdialkyl ether. Specific examples of these include ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, ethylene glycol dipropyl ether, ethylene glycol monobutyl ether, ethylene glycol dibutyl ether, propylene Glycol methyl ether, propylene glycol dimethyl ether, propylene glycol monoethyl ether, propylene glycol diethyl ether, propylene glycol monopropyl ether, propylene glycol dipropyl ether, propylene glycol monobutyl ether, propylene glycol dibutyl ether, and diethylene glycol, which is a condensate of glycol. Monoalkyl ether, diethylene glycol dialkyl ether, triethylene glycol monoalkyl ether, triethylene glycol dialkyl ether, tetraethylene glycol monoalkyl ether, tetraethylene glycol dialkyl ether, dipropylene glycol monoalkyl ether, dipropylene glycol dialkyl ether, tripropylene glycol Monoalkyl ether, tripropylene glycol dialkyl ether, tetrapropylene glycol monoalkyl ether, tetrapropylene glycol dialkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol dialkyl ether, polypropylene glycol monoalkyl ether,
Examples of the alkyl group in polypropylene glycol dialkyl ether and the like include chain hydrocarbons having 1 to 20 carbon atoms. Furthermore, glycol ethers obtained by reacting ethylene oxide and propylene oxide can also be used. The amount of these ethers (C) used is based on the titanium in the titanium-containing catalyst component (A).
/ Ti in (A) is used at 0.01 to 1.0 (molar ratio). Although the effect differs depending on the type of glycol ether, the catalyst activity in the case where glycol ether is not added is 30 to 80% (based on 100%).
It is preferable to add C). If the amount added is too large, the effect of inactivating the short-pass catalyst is large, but the overall catalytic activity is also greatly reduced, which is not economically preferable.
Control of the polymerization amount ratio of polymerization (i) and polymerization (iD) is limited, which is not preferable.On the other hand, if (C) is too small,
This is not preferable because the effect of selective inactivation of the Joetonoyas catalyst is insufficient.

It is unclear why the glycol ethers used in the present invention are significantly more effective than conventionally known ketones, amines, amides, alkyl ethers, carboxylic acid esters, and halogen compounds. reacts with the organoaluminium compound (B) to form an inert solvent-insoluble complex, which makes it difficult to oppose the catalyst inside the polymer particles, so the effect of preferentially inactivating the short-path catalyst is clearly expressed. It is also possible to do so. That is, it is assumed that the necessary conditions are the formation of a liquid complex that is insoluble in an inert solvent and the complex having a viscosity that makes it difficult to easily penetrate inside the polymer particles.

The addition of the above-mentioned glycol ethers in the polymerization step (H) is preferably carried out to the degassed slurry from the step (i) before starting the polymerization of the polymerization step (i), but it is not added to the polymerization vessel. The glycol ether may be added directly. The glycol ether may be added continuously or intermittently, but in the latter case, the addition interval is within 1/B of the residence time of the slurry in the polymerization vessel in the polymerization step (i). If this interval is long, the effect of the additive C will be insufficient.

The general polymerization conditions for the polymerization step (11) of the method of the present invention are:
It is as follows. That is, the polymerization temperature is 20 to 8
0°C1 preferably 40-70°C, pressure (-k
O~50kg/crn'G, average residence time is 20 minutes~10 hours.

Hydrogen is usually used to control the molecular weight, and the amount used is 1 to 40 mol % as the gas phase concentration in the polymerization vessel.

The proportion of monomers used is 10 to 100% by weight, preferably 20% by weight of ethylene and ethylene/propylene.
~70% by weight, the amount of polymerization! ±5 to 40% by weight, preferably 10 to 25% by weight, based on the ethylene/propylene block copolymer finally obtained. Further, in this polymerization step (ii), a small amount of other α-olefin or non-conjugated diene can also be used in combination, as in the case of polymerization step (i).

The main advantages of the method of the invention detailed below can be summarized as follows.

First, since the ethylene-propylene cloth used in the method of the present invention is wide, it has good fluidity during extrusion molding, and as a result, it is possible to increase the amount of extrusion by the extruder and save power consumption. can. Similarly, since it has characteristics such as excellent fluidity during injection molding, excellent results can be obtained in terms of quality and processing efficiency of molded products obtained when used in various molding fields.

Secondly, the method of the present invention is a multi-step polymerization method with a wide range of operating conditions for each polymerization vessel, and the management of the polymerization process and adjustment of the polymerization conditions can be carried out very easily.

As described above, the present invention has been able to achieve the above-mentioned effects, which were not possible with known techniques, by employing specific polymerization conditions and using additives (embodiments).

The present invention will be explained below with reference to examples, but they are not intended to limit the invention.

The analysis and measurement methods in Examples were as follows.

OMFR (g/10 min): ASTM D-'12
38.230°C, 2.18 kg load 0 Ethylene content (wt%): Infrared absorption spectroscopy 0 Polymerization ratio of polymerization (i) and polymerization (11) (t/wt):
Copolymers with different ethylene/propylene reaction ratios were made in advance, and this was used as a standard sample to create a calibration curve using infrared absorption spectroscopy to determine the ethylene/propylene reaction ratio of polymerization (-1). Calculated from the ethylene content (above) of all copolymers.

0 Calculation of MFR of polymer produced in each polymerization vessel: MFR+
; MFR of the polymer polymerized in S1 polymerizer (first
) MFR2, MFR of the polymer polymerized in the second polymerization vessel (*l
) MFR,. 2; MFR of all polymers produced in the first and second polymerization vessels Wl; ratio of all polymers produced in the first polymerization vessel in polymerization step (i) (second) W2; Proportion of total polymer produced in the double polymerization vessel (second) W+ + W2 = 1.0 First: Sampled and measured.

2nd: The titanium content in the polymer is fluorescent x1! It was analyzed and calculated using the method.

MFR,, was determined by the following relational expression.

Physical property measurement method of 0-sheet molded product: Young's modulus (kgf/ll1m'); ASTMD-
882 Punching impact strength (kgf/mrn'); AS
TMD-781 heating behavior; Chisso method (see below) In order to evaluate the heating vacuum properties of the sheet as a model, the sheet was fixed in a 40cm x 40cm frame, placed in a thermostatic chamber at 200°C, and the following physical properties were measured. did. In other words, a)
Drooping amount at the initial stage of sheet heating (mm), Maximum return amount m
:(1/150X (150-maximum recovery drooping amount (mm)
)X 100)) and ＼＼) is the holding time (seconds) from the time of maximum recovery to the time of restarting drooping.

Sheet appearance: Visual observation Example 1 1) Production of catalyst 6 moles of n-hexane, 5.0 mol of diethylaluminium monochloride (i) EAG), 1 mole of diisoamyl ether
2.0 mol was mixed at 25°C for 5 minutes and reacted at the same temperature for 5 minutes to obtain reaction product liquid (1) (diisoamyl ether/DEAC molar ratio 2.4). 40 moles of titanium tetrachloride was placed in a reactor purged with nitrogen and heated to 35°C.
The entire amount of the reaction product solution (I) was added dropwise to this over 180 minutes, kept at the same temperature for 30 minutes, heated to 75°C and reacted for another hour, cooled to room temperature, and removed the supernatant. n-
The operation of adding 30 grams of hexane and removing by decantation was repeated four times to obtain 1.9 kg of solid product (II).

The entire amount of (II) was suspended in 30 volumes of n-hexane, and 1.6 kg of diisoamyl ether and 3.5 kg of titanium tetrachloride were added at room temperature for about 5 minutes at 20°C.
The reaction was carried out at 5°C for 1 hour. After the reaction is completed, room temperature (20'
After cooling to 0) and removing the supernatant liquid by decantation, add 30 grams of n-hexane, stir for 15 minutes, leave to stand and remove the supernatant liquid, repeat the operation 5 times, and then remove the supernatant liquid under reduced pressure. After drying, a solid product (III) was obtained.

2) Adjustment of catalyst In a tank with an internal volume of 50 g, 40 g of n-hexane, 850 g of diethylaluminium chloride, and 360 g of the above solid product were added.
g, methyl paratorny), then add 3.8 g, then 3.
While maintaining stirring at 0°C, add 180g of propylene gas/
Pretreatment was carried out by supplying H for 2 hours.

3) Polymerization method The polymerization was carried out using the polymerization apparatus shown in the figure.

N-hexane 2+31/H1 catalyst slurry 120+oQ/H was continuously supplied to the polymerization vessel 1 every hour. Polymerization vessel 1~
The temperature of 2 is 70℃, and the pressure is 6 kg/crn'.
Propylene was supplied to each polymerization vessel and adjusted so that G was 8 kg/crn'G.

Further, 50ON4Q/H of gas was continuously discharged from the polymerization vessel (2). Each polymerization vessel was drained using a control valve so that the liquid level was 80%. The gas from the degassing tank was compressed by a compressor and circulated to the polymerization vessel (1). In addition, the reaction amount and MFR analysis values for each polymerization vessel are shown in Table 1.
It was as shown.

The slurry containing polymer particles extracted from the polymerization vessel (2) is stored in a degassing tank (1) at 60°C and 0.5 kg/ctn'.
The mixture was degassed with G and transferred to the polymerization vessel (3) using pump 6. The gas phase hydrogen concentration in the polymerization vessel (3) was 10 mol%, and the temperature was 6.
At 0° C., ethylene was supplied at a rate of 5008/H, and propylene and hydrogen were supplied so that the gas composition of the gas phase was ethylene/(ethylene+propylene)=0.40. Polymerization vessel (3
) The slurry exiting from the tank passes through the degassing tank (2), and after deactivating the catalyst with methanol, it is neutralized with caustic soda water.
After washing with water, separating, and drying, the white copolymer powder is produced in about 50%.
It was obtained at 5 kg/H.

Also, the analysis values are shown in Table 1.

4) Granulation method and sheet forming method To 15 kg of the white polymer powder obtained above, Bl(T
■(2,8-t-Butyl-P-cresol)15
g, Irganox 1010■ (Tetrakis
(Nethylene (3,5-di-t-but
yl-4-Hydr.

cinnamate) methane) 7.5g
, 30g of Calcium stearate was added and granulated using a 4Qmmφ granulator. The granules were then processed at 225°C using a 50 mmφ extrusion molding machine to produce a sheet with a width of 80 cm and a thickness of 0.4 mm, and the physical properties of the sheet were measured using the method described above. The results are shown in Table-2.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the gas phase gas was not discharged from the polymerization vessel (2). The resulting polymer had poor sheet heating behavior.

Comparative Example 2 Comparative Example 1 was carried out with the same gas phase concentration in the polymerizers (1) and (2) being supplied together with hydrogen. In this case as well, the heating behavior of the sheet was significantly inferior.

Examples 2-4. Comparative Examples 3 to 4 Table (1) shows the gas phase hydrogen concentration and exhaust gas amount in Example 1.
It was implemented with the following changes. If the amount of exhaust gas was insufficient, the heating behavior was inferior, and if it was too much, the appearance of the sheet molding surface was poor (due to non-uniform fluidity).

Example 5 In Example 1, diethylene glycol dimethyl ether (a) was added to the degassing tank (1) so that a/Ti = 0.3 (molar ratio) to the titanium in the solid catalyst, and then the polymerization vessel (3 ) was carried out at a hydrogen concentration of 2.0 mol % in the gas phase. A significant improvement in low-temperature punching impact strength was observed.

Comparative Example 5 Example 5 was carried out except that the addition of diethylene glycol dimethyl ether was omitted. Frequent occurrence of FE and decrease in punching impact strength were observed in the sheet appearance.

Example 6 In Example 5, methyl paratoluate was added to a polymerizer (1 g) per 1 g of solid product in the catalyst slurry.
). Also, the supply amount of catalyst slurry is 240mKL.
/H. As shown in the table, when this catalyst system was used, a significant increase in Young's modulus and improvement in heating behavior were observed.

Comparative Example 6 The same procedure as in Example 6 was carried out except that addition of diethylene glycol and dimethyl ether was omitted. FE occurred frequently and punching impact strength decreased.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet of a polymerization apparatus used in Examples of the present invention. In the figure, 1: Polymerization vessel (1), 2: Polymerization vessel (2), 3: Degassing tank (1), 4: Polymerization vessel (3), 5: tt
(2), 6: Pump 7: Control valve. that's all

Claims (1)

[Scope of Claims] (1) In a method for continuously producing an ethylene-propylene copolymer using a Ziegler-Natta type catalyst, a. Continuous polymerization step (i) in which propylene is the main component, by supplying monomers in which the weight ratio of ethylene and ethylene + propylene in the supplied monomers is 0 to 5% by weight to a polymerization vessel of 2 or more tanks including 1 to 2 tanks. Then, into one or more polymerization vessels that were not used in step (i), monomers with a weight ratio of ethylene and ethylene + propylene in the supplied monomers of 10 to 100% by weight are supplied, and the process is continued from the previous step. Also, a continuous polymerization step (ii) containing a relatively large amount of ethylene is carried out, and (b) the entire amount of the catalyst used is supplied to the first tank, and the supplied catalyst is sequentially transferred to the second tank and subsequent tanks together with the polymerization reaction mixture. via
The polymers polymerized in each stage of polymerization vessels are additionally formed on the same catalyst solid and then discharged from the final vessel, and (c) in the continuous polymerization step (i) mainly consisting of propylene, a molecular weight regulator is added. Using hydrogen gas, the entire amount of hydrogen gas is supplied to the first tank, and from the second tank onwards,
The residue consumed in each pre-tank becomes the polymerization reaction mixture (slurry)
d. In the continuous polymerization step (i) mainly consisting of propylene, gas is continuously extracted from the gas phase of the polymerization vessel from the second tank onwards, and the amount of gas is set to the volume of the polymerization vessel as V_1. In this case, 0℃, 0kg/cm^2G conversion is 0.5 per hour.
V_1 to 10V_1, and (e) the amount of polymerization in the polymerization step (i) is 60 to 95% by weight of the total amount of polymerization. (2) In the continuous polymerization step (i) mainly containing propylene, the molecular weight of the polymer produced in the first and last polymerization vessels is within the range of the following formula (1) as an MFR value. Continuous manufacturing method according to scope item (1). log(MFR_i/MFR_t)≧2.0 However, MFR_i: MFR of the polymer produced in the i-th polymerization vessel
MFR_t: Continuous polymerization process mainly using propylene (i
) of the polymer produced in the final polymerization tank (3
) In the continuous polymerization step (i) mainly containing propylene, the gas extracted from the gas phase of each of the second and subsequent polymerization vessels is circulated to the first polymerization vessel and reused. The manufacturing method described in paragraph (1). (4) Organoaluminum compound (B) combined with the titanium-containing solid component (A) constituting the Ziegler-Natta catalyst
) as the general formula AlR^l_mX_3_-_m (in the formula R
^2 represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a halogen atom, and m represents a number of 3≧m>1.5), and the continuous polymerization step (i) is carried out. The reaction is carried out in the presence of an inert solvent or liquid propylene, and glycol ethers (C) are added to the polymerization reaction mixture (slurry) after the completion of the step, with respect to the titanium component in (A), (C)/( A) is continuously added so that the concentration of Ti in A) is 0.01 to 1.0 (mol/atom), and the continuous polymerization step (
ii) The continuous manufacturing method according to claim (1).