JPS63165417A - Production of propylene block copolymer - Google Patents

Abstract

PURPOSE:To obtain the titled copolymer outstanding in rigidity, impact strength and moldability, by polymerization of propylene using a catalyst consisting of a specific solid Ti catalytic component and organoaluminum compound followed by adding an alkoxytitanium and organoaluminum compound to carry out a copolymerization with ethylene. CONSTITUTION:The objective copolymer can be obtained, using a Ziegler type catalyst consisting of (A) a solid Ti catalytic component comprising Mg, Ti, halogen and electron donor as the essential components, respectively, and (B) an organoaluminum compound by, in the first stage, making either crystalline propylene homopolymer or propylene copolymer, and then by, in the second stage, adding an alkoxytitanium compound and organoaluminum compound to carry out a copolymerization, in the presence of the polymer produced in the first stage, between propylene and ethylene in the molar ratio: 0/100-80/20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background of the Invention] Technical Field The present invention relates to a method for producing a propylene block copolymer that has high rigidity, high impact strength, and excellent moldability.

Prior Art Conventionally, in the presence of various types of stereospecific catalysts, a crystalline homopolymer or copolymer of propylene (hereinafter both may be collectively referred to simply as polypropylene) is produced in the first stage, and then in the second stage. Producing a rubbery copolymer of propylene by copolymerizing propylene and another α-olefin in the presence of the polypropylene and/or a crystalline homopolymer or copolymer of other α-olefin. It is known to produce, inter alia, ethylene or ethylene-based crystalline homopolymers or copolymers. It is known that such a multi-stage polymerization method can yield a composition that maintains the excellent rigidity of polypropylene and has improved impact resistance at low temperatures.

The composition is usually an intimate mixture of homopolymers or copolymers produced in each step and is commonly referred to as a block copolymer. Such block copolymers are often used, for example, in containers, automobile parts, low-temperature heat-sealable films, high impact-resistant films, and the like.

A titanium trichloride type catalyst has conventionally been used as a catalyst for producing such a block copolymer, but this requires a catalyst removal step, that is, a decatalyzing step, because of its low catalytic activity.

In recent years, many methods using supported catalysts have been proposed as a method to greatly improve the activity to the point where the decatalyzing step becomes unnecessary (JP-A-52-98045, JP-A-53-8).
No. 8049, JP-A-58-83016, etc.).

However, compared to conventional titanium trichloride type catalysts, carrier-type catalysts have a lower molecular weight in the copolymerization part in the latter stage, resulting in a narrower molecular weight distribution of the block copolymer and poor formability (spiral flow) during processing. There was a problem.

The present inventors have already discovered that moldability during processing can be significantly improved by adding a special electron donor at the start of the first stage polymerization, as in the invention of Japanese Patent Application No. 60-59139. We have been conducting intensive studies to make further improvements.

On the other hand, for the purpose of improving the adhesion of polymer particles, a method has recently been proposed in which an electron-donating compound is added at the start of the subsequent polymerization (JP-A-61-69821, JP-A-61-69822).
No. 61-69822).

However, these methods have not been able to improve the moldability of block copolymers.

[Summary of the invention]

Summary The present invention aims to provide a solution to the above-mentioned intermediate point,
When carrying out block copolymerization using a carrier type catalyst or medium, the moldability of the block copolymer can be significantly improved by adding specific additives at the end of the first stage polymerization.

That is, the method for producing a propylene block copolymer according to the present invention is a Ziegler polymer formed from (A) a solid titanium catalyst component containing magnesium, titanium, halogen, and an electron donor as essential components, and (B) an organoaluminum compound. In the presence of a type catalyst, a crystalline homopolymer or copolymer of propylene is produced in the former step, and in the latter step, propylene and ethylene are mixed in the presence of the homopolymer or copolymer at a polymerization ratio (mole). Ratio) A method for producing a propylene block copolymer comprising polymerizing at a ratio of 0/100 to 80/20, characterized by adding an alkoxytitanium compound and an organoaluminum compound during the latter stage polymerization. .

Effects By producing a propylene block copolymer using the method of the present invention, a propylene block copolymer with high rigidity, high impact strength, and excellent moldability could be obtained using a carrier-type highly active catalyst. .

[Detailed description of the invention]

Catalyst Components The catalyst used in the present invention is formed from component (A>) and component (B), and falls within the category of Ziegler type catalysts.

Here, "formed from component (A) and component (B)"
It should be understood that this does not exclude cases where a third component that does not unduly impair the effects of the present invention, or more preferably a third component that takes advantage of the present invention, is included. A typical example of such a third component is an electron donor compound (component (C)) as a so-called external donor.
The catalyst formed from components (A), (B) and (C) constitutes a preferred embodiment of the present invention.

The catalyst of the present invention can be said to further contain specific compounds, ie, an alkoxytitanium compound and an organoaluminum compound, in the latter stage of block copolymerization.

Component (A) The solid titanium catalyst component (A) used in the present invention contains magnesium, titanium, norogen, and a g-child donor as essential components. Here, "making it an essential component" means not only when the solid titanium catalyst component A consists only of these three specific components, but also when the solid titanium catalyst component A consists of only these three specific components. This means that additional ingredients may be included as long as they do not detract from them. Such additional components are, for example, /-logenated silicon compounds.

Magnesium is usually introduced into component (A) by means of magnesium halides, titanium by means of titanium compounds, and halogens by means of these compounds.

(1) Magnesium halide “Magnesium halide is preferably magnesium dihalide, and magnesium chloride, magnesium bromide, and magnesium iodide can be used. More preferably, it is magnesium chloride, and further, it is substantially anhydrous. It is desirable that there be.

In addition, magnesium halides include magnesium oxide,
Magnesium hydroxide, hydrotalcite, magnesium carboxylate, alkoxymagnesium, allyloxymagnesium, alkoxymagnesium halide, allyloxymagnesium halide, organomagnesium compound as an electron donor, halosilane, alkoxysilane, silanol, A1 compound, halogenated Magnesium halide obtained by treatment with a titanium compound, titanium tetraalkoxide, etc. may also be used.

(2) Titanium Compounds Typical titanium compounds are trivalent and tetravalent titanium halogen compounds. Preferred titanium halogen compounds are n-0, 1 or 2 tetravalent halogenated titanium compounds among compounds represented by the general formula % (hydrogen residue, X is halogen). Specifically, T iCl 4, Ti (OB
u) CI Ti (OBu)2C123ゝ can be exemplified, but TL is particularly preferable.
These are tetrahalogenated titanium and monoalkoxytrihalogenated titanium compounds such as CI and T i (OB u) CI 3. As a titanium compound, a titanium compound that does not contain halogen, specifically T L (OB
u) 4 etc. are also preferably used.

(3) Electron Donor Compound The electron donor compound which is an essential component of the solid catalyst component (A) of the present invention is at least one of the specific compounds (a) to (c). Among these, compound (C) is particularly preferred.

(a) One of the electron donor compounds is an ester (a) of a polyfunctional compound selected from the group consisting of polyhydric carboxylic acids, polyhydric alcohols, and hydroxy-substituted carboxylic acids. Suitable esters of these polyfunctional compounds are, for example, those represented by the following formula.

R3-C-0COR7, -6-oooR6, Ma'' R3-C-COOR5 R4-U100OR2 Here, R5 is a substituted or unsubstituted hydrocarbon group, and R
2, R3 and R4 are hydrogen or a substituted or unsubstituted hydrocarbon group, and R and R7 are hydrogen or a substituted or unsubstituted hydrocarbon group, preferably at least one of which is a substituted or unsubstituted hydrocarbon group. That which is the basis. R3 and R4 may be connected to each other. Examples of the substituted hydrocarbon group include those containing different atoms such as N, 0, and S, such as C-0-C and C0OR.

Some have groups such as C0OH, OH, 5o3H, -C-N-C-1NH2.

Particularly preferred among these are diesters of dicarboxylic acids in which at least one of R5 and R2 is an alkyl group having 2 or more carbon atoms.

Specific examples of preferred polyhydric carboxylic acid esters include (a) diethyl succinate, dibutyl succinate,
Diethyl methylsuccinate, diisobutyl α-methylglutarate, dibutyl methylmalonate, diethyl malonate,
Diethyl ethylmalonate, diethyl isopropylmalonate, diethyl butylmalonate, diethyl phenylmalonate, diethylmalonate, diethyl allylmalonate, diethyl diisobutylmalonate, diethyl di-n-butylmalonate, dimethyl maleate, monooctyl maleate, Dioctyl maleate, dibutyl maleate, dibutyl butyl maleate, diethyl butyl maleate, diisopropyl β-methylglutarate, diallyl ethylsuccinate, di-2-ethylhexyl fumarate,
Aliphatic polycarboxylic acid esters such as diethyl itaconate, dibutyl itaconate, dioctyl citraconate, dimethyl citraconate, (b) diethyl 1,2-cyclohexanecarboxylate, diisobutyl 1,2-cyclohexanecarboxylate, diethyl tetrahydrophthalate, aliphatic polycarboxylic acid esters, such as diethyl nazic acid;
(c) Monoethyl phthalate, dimethyl phthalate, methylethyl phthalate, monoisobutyl phthalate, mononormal butyl phthalate, diethyl phthalate, ethylisobutyl phthalate, ethyl normal butyl phthalate, di-n-propyl phthalate, phthalate diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-n-hebutyl phthalate, di-2-ethylhexyl phthalate, di-n phthalate
- Aromatic polycarboxylic acid esters such as octyl, dineopentyl phthalate, didecyl phthalate, benzylbutyl phthalate, diphenyl phthalate, diethyl naphthalene dicarboxylate, dibutyl naphthalene dicarboxylate, triethyl trimellitate, dibutyl trimellitate, ) Different carbon polycarboxylic acid esters such as 3,4-furandicarboxylic acid can be mentioned.

In addition, specific examples of preferable polyvalent hydroxy compound esters include 1,2-diacetoxybenzene,
1-Methyl-2,3-diacetoxybenzene, 2.3-
Examples include diacetoxynaphthalene, ethylene glycol dipiparate, butanediol pivalate, and the like.

Examples of esters of hydroxy-substituted carboxylic acids include benzoylethyl salicylate, acetyl isobutyl salicylate, acetyl methyl salicylate, and the like.

Other examples of polyvalent carboxylic acid esters that can be supported in the titanium catalyst component include diethyl adipate,
Diisobutyl adipate, diisopropyl sebacate,
Di-n-butyl sebacate, di-n-octyl sebacate,
Mention may be made of esters of long-chain dicarboxylic acids such as di-2-ethylhexyl sebacate.

Preferred among these polyfunctional esters are those having the skeleton of the general formula described above, and more preferred are esters of phthalic acid, maleic acid, substituted malonic acid, etc., and alcohols having 2 or more carbon atoms. Particularly preferred is a diester of phthalic acid and an alcohol having 2 or more carbon atoms.

(b) Still another group of electron donor components that are essential components of the solid catalyst component (A) is R8C00R9 (R8, R
9 is a hydrocarbyl group having about 1 to 15 carbon atoms,
A monocarboxylic acid ester, at least one of which is a branched (including alicyclic) or ring-containing chain group. Examples of R8 and/or R9 include (CH) CH-1C2Hs CH(CH3)-
1(CI('') CHCH2-1(CH3) 3G-
1CI(CH(CH3)CTl2-1 QcH2-1CH3+c H:2-1 can be exemplified.If either R and R9 is a branched group as described above, even if the other is the above group) , or other groups such as linear or cyclic groups.

Such monocarboxylic acid esters include various monoesters such as α-methylbutyric acid, β-methylbutyric acid, methacrylic acid, and benzoyl acetic acid, various monocarboxylic acids of alcohols such as isopropanol, isobutyl alcohol, and tertiary butyl alcohol. An example is ester.

(c) Organosilicon compound As the electron donor compound, an organosilicon compound represented by the general formula 1% RS 1 (OR) 3 can be selected. In the formula, R10 is a cyclic aliphatic hydrocarbon group, preferably a bicyclic hydrocarbon group having 3 to 20 carbon atoms, more preferably 5 to 12 carbon atoms. R11 is
It is a cyclic or chain aliphatic hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. R12 is a cyclic or chain aliphatic hydrocarbon group, preferably a chain aliphatic hydrocarbon group having 4 or less carbon atoms. Specific examples are shown below using structural formulas.

Furthermore, an organosilicon compound represented by the following formula can also be selected.

R14,15 RR3-n51(OR)n (where R13 is a branched hydrocarbon residue, R14 and R15 are each a branched or linear hydrocarbon residue, n
is a number with 2≦n≦3).

RlB is preferably one in which the carbon atom adjacent to the silicon atom is branched. In that case, the branching group is preferably an alkyl group, a cycloalkyl group, or an aryl group (eg, a phenyl group or a methyl-substituted phenyl group). More preferable R13 is that the carbon atom adjacent to the silicon atom, that is, the carbon atom at the α-position, is secondary or tertiary.
It is a carbon atom of class.

Particularly preferred are those having a structure in which three alkyl groups extend from a carbon atom bonded to a silicon atom. R13
The number of carbon atoms is usually 3 to 20, preferably 4 to 10. R14 is usually a branched or linear aliphatic hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. R15 is usually an aliphatic hydrocarbon group, preferably a chain aliphatic hydrocarbon group having 1 to 4 carbon atoms.

Specific examples are shown below using structural formulas.

(CH) CS 1 (OCH3) 2 (CM)
C-5i (OCH3) 2(CH3)3C-8i(O
C2H5)2H3 H3 (CH3)3C-8i(OCH3)3 (CH3)3C-8i(OC2H5)3(C2H5)3
C-8i(OC2H5)3 When incorporating these electron donor components into the solid catalyst component A, it is not necessarily necessary to use them as starting materials, and compounds that can be converted into these in the process of preparing the solid catalyst component may be used. These compounds may be converted into these compounds at the stage of preparation.

(4) Preparation of solid catalyst component A In preparing the solid catalyst component (A), it is desirable that the magnesium halide be pretreated in advance. This preliminary treatment can be performed by various conventionally known methods, and specifically, the following methods can be exemplified.

(a) Grinding magnesium dihalide, or magnesium dihalide and a halogen compound of titanium, silicon or aluminum, or a halogenated hydrocarbon compound. Grinding can be performed using a ball mill or an oscillating mill.

(b) Magnesium dihalide is dissolved using a hydrocarbon or halogenated hydrocarbon as a solvent and alcohol, phosphoric acid ester, or titanium alkoxide as a dissolution promoter. Next, the dissolved magnesium dihalide is precipitated by adding a poor solvent, an inorganic halide, an S-child donor such as an ester, or a polymeric silicon compound such as methylhydrodiene polysiloxane to this solution.

(c) Bringing a halogenating agent into a contact reaction with a magnesium mono- or sialicolate or a magnesium carboxylate.

(d) Bringing magnesium oxide and chlorine or AlCl3 into a catalytic reaction.

(e) Contact reaction between MgX2#nH20 (X is halogen) and a halogenating agent or TiC14.

(to) M g X 2 ・n ROH (X is halogen, R is alkyl halogenating agent or T t C1
4 and undergo a contact reaction.

(g) Grignard reagent, M g R2 compound (R
is an alkyl group), or a complex of an MgR2 compound and a trialkylaluminum compound, using a halogenating agent such as AIX AIRX (X is 3ゝ・m
3-+n halogen, R is an alkyl group), 5ic14 or HS L C13.

(H) A Grignard reagent and a silanol or a polysiloxane, R20, or a silanol are brought into contact reaction, and then a halogenating agent or TIC14 is brought into contact reaction.

For details on such pretreatment of magnesium halides, see Japanese Patent Publication Nos. 46-611 and 46-34092.
No. 51-3514, No. 56-67311, No. 5
No. 3-40632, No. 56-50888, No. 57-4
No. 8565, No. 52-36786, No. 58-449, No. 53-45686, No. 50-126590, No. 54-31092, No. 55-135102, No. 55-135103, No. 56- No. 811, 56-1
No. 1908, No. 57-180612, No. 58-530
No. 9, No. 58-5310, and No. 58-5309 can be referred to.

Contacting the pretreated magnesium chloride with the titanium halide and the electron donor compound can also be carried out by forming a complex between the titanium halide and the electron donor compound and then contacting this complex with the magnesium chloride. After bringing magnesium chloride and titanium halide into contact,
It may be brought into contact with an electron donor compound, or it may be brought into contact with magnesium chloride and an electron donor compound and then brought into contact with titanium halide.

The contact may be carried out by pulverization using a ball mill, vibration mill, or the like, or by adding magnesium chloride or an electron donor-treated product of magnesium chloride to the liquid phase of titanium halide.

Washing with an inert solvent may be performed after contacting the three or four components or at an intermediate stage of contacting each component.

The titanium halide content of the solid catalyst component A thus produced is 1 to 20% by weight, the content of magnesium halide is 50 to 98% by weight, and the molar ratio of the electron donor compound to the titanium halide is 0. It is about .05 to 2.0.

Component (B) The organoaluminum compound used as component (B) in the present invention has the general formula AIRX (where n 3-n , R is a hydrocarbon residue having 1 to 12 carbon atoms, X is a halogen or an alkoxy group, (n represents Own≦3) is preferable.

Such organoaluminum compounds are specifically, for example, triethylaluminum, trilopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, triisohexylaluminum, trioctylaluminum, diethylaluminium. hydride, diisobutylaluminum hydride, diethylaluminum monochloride, ethylaluminum sesquichloride, diethylaluminum monoethoxide, etc. Of course, two or more of these organoaluminum compounds can also be used in combination.

The ratio of the organoaluminum compound (B) and the solid catalyst component (A) used in the polymerization of α-olefins can vary over a wide range, but is generally 1 to 1000, preferably 1 to 1,000 per titanium atom contained in the solid catalyst component. is 1
The organic aluminum compound can be used in a ratio of 0 to 500 (mole ratio).

Component (C) In the block copolymer of the present invention, various electron donors can be used as necessary.

As the electron donor, ether, amine, organosilicon compound, etc. are preferably used. A specific example is shown below.

(a) Ether compound An example of ether used in the present invention is an ether represented by the general formula. In the formula, R1-R3 are saturated or unsaturated hydrocarbon residues, generally having 1 to 10 carbon atoms.
an alkyl or alkenyl group (including substituted derivatives substituted with a halogen or phenyl group), preferably having about 1 to 4 carbon atoms, or a phenyl group, having 6 to 12 carbon atoms, preferably about 6 to 10 carbon atoms. groups (including substituted derivatives with halogen, alkyl groups (especially lower alkyl groups) or phenyl groups). However, among R1-R3, 1 to
Two are phenyl groups (including substituted derivatives with halogen or alkyl groups (especially lower alkyl groups)). R
4 is a hydrocarbon group.

Specific examples of such ether compounds include a-cumyl methyl ether, α-cumyl ethyl ether, 1.
1-Diphenylethyl methyl ether, 1,1-diphenylethyl ethyl ether, α-cumyl tert-butyl ether, diα-cumyl ether, 1,1-ditolylethyl methyl ether, 1,1-ditolylethyl ethyl ether, bis (1,1-ditolylethyl)ether, 1-tolyl-1-methylethylmethylether, and the like.

In addition to the above, ether compounds such as 1.4-cineole, 1.8-cineole, and m-cineole can also be used.

(b) Amine compound The amine compound used in the present invention has a 2,2°6.6-
These are sterically hindered amines such as titramethylpiperidine and 2,2,6°6-titraethylpiperidine.

(C) Organosilicon compound Specific examples of the organosilicon compound used in the present invention can be found in the above-mentioned examples of the organosilicon compound (C) used as an electron donor compound contained in the solid titanium catalyst component. However, among these, dialkoxy or trialkoxysilanes are preferably used. A specific example is shown as a structural formula as follows.

Molar ratio of H3 (CH3)3C-8i(OCH3)3 (CH3)3C-8i(OC2H5)3 to H3 (C2H5)3C-8i(OC2H5)3 (C) electron donor and (B) organoaluminum compound is usually 0.01 to 1.01, preferably 0.02 to 0.5.

Block copolymerization The polymerization step of the present invention, which is carried out in the presence of a catalyst, produces a crystalline homopolymer or copolymer of propylene.

It consists of three steps: first-stage polymerization to produce a compound, addition of an alkoxytitanium compound and organoaluminium compound, and second-stage polymerization to polymerize propylene and ethylene at a polymerization ratio (mole ratio) of 0/100 to 80/20.

First-stage polymerization In the first-stage polymerization, propylene alone or a propylene/ethylene mixture is supplied to the polymerization system containing the catalysts (A), (B), and optionally (C), to form a propylene homopolymer or a propylene homopolymer or a propylene containing 7% by weight or less of ethylene. , preferably 1.0% or less, of a propylene/ethylene copolymer in one or more stages, 50 to 95% by weight of the total polymerization amount, preferably 60 to 9% by weight of the total polymerization amount.
This is a step of forming the film in an amount corresponding to 0'% by weight.

If the ethylene content in the propylene/ethylene copolymer increases further than this in the first stage polymerization, the bulk density of the final copolymer will decrease and the amount of by-product of low crystallinity polymer will increase significantly. Furthermore, even if the polymerization ratio is less than the above range, the same phenomenon as in the case where the ethylene content in the propylene/ethylene copolymer is high still occurs. On the other hand, if the polymerization ratio exceeds the above range, although the amount of by-product of the low crystalline polymer tends to decrease, it is not preferable because the impact strength, which is the objective of block copolymerization, decreases.

The polymerization temperature in the first stage polymerization is 30 to 90°C, preferably 50°C.
The temperature is about 80°C. Polymerization pressure is 1 to 30 kg/c
It is about d.

In the first stage polymerization, it is preferable to use a molecular 'Eik3M moderator so that the final polymer has appropriate fluidity.
It is preferable to use hydrogen as the molecular weight regulator.

Addition of alkoxytitanium compound and organoaluminum compound Preferred alkoxytitanium compounds to be added during the pre-polymerization are tetraalkoxytitaniums, ie, tetraalkyl titanates.

Specific examples include tetraethyl titanate, tetra n-propyl titanate, tetramypropyl titanate, tetra t-butyl titanate, tetra n-hexyl titanate, in which the alkyl group has about 1 to 10 carbon atoms, especially about 2 to 8 carbon atoms. Examples include tetraoctyl titanate, among which alkyl titanates having 3 or more carbon atoms are preferred, and tetra n-butyl titanate is particularly preferred.

The amount of the alkoxy titanium compound added is usually 1 to 200 mol, preferably 5 to 50 mol, per 1 mol of titanium in the catalyst (A) component.

As the organoaluminum compound added in the latter stage polymerization, the organoaluminum compounds exemplified in the catalyst component (B) are used, and trialkylaluminum such as triethylaluminum, tri-n-propylaluminum, and trimybutylaluminum are particularly preferably used. It will be done.

It is usually added in a molar ratio of 0.1 to 1.0 with respect to the organoaluminum compound and alkoxytitanium compound added here.

Alkoxy titanium compounds and organoaluminum compounds are
They may be added to the polymerization system separately, or they may be brought into contact with each other in advance and then added.

When both are added separately, either may be added first.

These two may be added during the first stage polymerization or during the second stage polymerization. The preferred time of addition is
This is at the end of the first stage of heavy metalization or at the beginning of the second stage of polymerization.

Post-polymerization In the post-polymerization, following the pre-polymerization, a propylene/ethylene mixture is further introduced to contain ethylene! 120～
This is a process for obtaining 100% by weight, preferably 30 to 100% by weight, more preferably 75 to 95% by weight of a propylene/ethylene copolymer in one or multiple stages. In this step, 5 to 50% by weight of the total polymer amount, preferably 10 to 4% by weight,
It is desirable to form an amount corresponding to 0.2%.

If the polymerization ratio in the latter stage polymerization and the composition of the propylene/ethylene mixture are less than the above ranges, impact resistance (especially low-temperature impact resistance) will be poor and the effect of improving spiral flow will be small. Moreover, when the above range is exceeded, operational problems such as a significant increase in the amount of by-product of the low crystalline polymer and a significant increase in the viscosity of the polymerization solvent occur.

In the latter stage polymerization, a small amount of other comonomers may be present. Examples of such comonomers include α-olefins such as 1-butene, 1-pentene, and 1-hexene.

The polymerization temperature in the latter stage polymerization is 30 to 90°C, preferably 50 to 90°C.
The temperature is about 80°C. The polymerization pressure is about 1 to 30 kg/c.

When moving from the first-stage polymerization to the second-stage polymerization, it is preferable to purge the propylene gas or propylene/ethylene mixed gas and hydrogen gas derived from the first-stage polymerization before moving on to the second-stage polymerization.

In the second-stage polymerization, 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.

Polymerization Method The method for producing the copolymer according to the present invention can be carried out by any of the batch, continuous and semi-batch methods. At this time, there are methods of conducting polymerization in an inert hydrocarbon solvent such as heptane, methods of using the monomer itself as a medium, and methods of conducting polymerization in a gaseous monomer without using a medium. , and a method that combines these methods can also be adopted. The first stage polymerization and the second stage polymerization may be carried out in separate polymerization tanks.

Furthermore, before subjecting the solid catalyst to polymerization, preliminary polymerization can be carried out under milder conditions than the planned polymerization conditions (JP-A-55-71712, JP-A-56-57814).
(see publication).

EXPERIMENTAL EXAMPLES The following examples are intended to further illustrate the present invention. These are illustrative of some embodiments of the invention and are not intended to limit the invention.

Example 1 (l) Preparation of solid catalyst component Into a glass Mitsuro flask (with thermometer and stirring frame) having an internal volume of 5001 and purged with nitrogen, 751 purified hebutane, 751
Add 5 ml of titanium tetrabutoxide and 10 g of anhydrous magnesium chloride. Thereafter, the temperature of the flask was raised to 90° C., and the magnesium chloride was completely dissolved over a period of 2 hours. Next, the flask was cooled to 40° C., and methylhydrodiene polysiloxane 151 was added to precipitate a magnesium chloride/titanium tetrabutoxide complex. This was washed with purified butane to obtain an off-white solid.

20 g of the precipitated solid obtained above was placed in a glass Mitsuro flask (with thermometer and stirring bar) having an internal volume of 300 cm, which was purged with nitrogen.
A heptane slurry containing 65ff11 was introduced. Next, silicon tetrachloride8. Heptane solution containing 7 ml 25
1 was added over 30 minutes at room temperature, and the mixture was further reacted at 30°C for 30 minutes. The reaction was further carried out at 90°C for 1 hour, and after the reaction was completed, the reaction mixture was washed with purified hemobutane. Then, in addition to 50 ml of a heptane solution containing 1.61 phthaloyl chloride, 50
℃ for 2 hours, followed by washing with purified butane,
Furthermore, 25 ml of titanium tetrachloride was added and the mixture was reacted at 90°C for 2 hours. This was washed with purified butane to obtain a solid catalyst component. The titanium content in the solid catalyst component was 3.22% by weight.

(2) After sufficiently purging a stirred autoclave with a polymerization internal volume of 200 liters with propylene, 60 liters of dehydrated and deoxygenated n-hebutane was introduced, and triethylaluminum (B)
6. OK, the solid composition (A)3. og and 6.4 g of diphenyldimethoxysilane were introduced at 70° C. under a propylene atmosphere.

In the first stage polymerization, after raising the temperature of the autoclave to 75°C, the hydrogen concentration was adjusted to 2. 9kg of propylene while keeping it at 0%
/ Started by introducing at the speed of time.

After 215 minutes, the introduction of propylene was stopped and the polymerization was further continued for 7 minutes.
It was continued for 90 minutes at 5°C. Propylene in the gas phase is 0,
It was purged to 2 kg/cd G.

Next, 1-6.8 g of tetra-n-butyl titanium and 1.0 g of triethylaluminum were added, and after lowering the temperature of the autoclave to 60°C, the second stage polymerization was carried out using 1.57 k of propylene.
g/hour, ethylene at a feed rate of 2.35 kg/hour for 87 minutes.

The slurry thus obtained was filtered and dried for 3
6.4 kg of powdered block copolymer was obtained.

Details of the results are shown in Table 1.

The ffi amount ratio of the produced polymers in the first-stage polymerization and the second-stage polymerization and the weight ratio of propylene and ethylene in the second-stage polymerization are calculated values on a feed basis.

(3) Measurement of physical properties (b) MFR MFR was measured according to ASTM-1238.

(b) Ethylene content The ethylene content in the product was calculated from the IR absorption spectrum.

(c) Measurement of practical physical properties The powdered polymers obtained in each example and comparative example were mixed with the following additives, pelletized using an extruder under the same conditions, and a sheet with a thickness of 4 mm was created using an injection molding machine. Then, the physical properties were evaluated.

Additives 2.6-Ditert-butylphenol 0.10% by weight Al0IO (manufactured by Ciba Geigy) 0.05% by weight Calcium stearate 0.10ffiffi% PTBBA-
AL (shell chemical type) 0.10% by weight Measurement of physical properties Various physical properties were measured by the following methods.

(a) Flexural modulus: ASTM-D790 (b) Izot impact strength (0°C): ASTM-D256 (with notch) (c) Spiral flow measurement method Each machine Using an SJ type (in-line screw type) injection molding machine The cross section is 2 dragons x 811! The measurement was carried out using a mold of No. 1 under the following conditions.

Molding temperature: 240°C Injection pressure 800 kg/cj Injection time: 6 seconds Mold temperature = 40°C Injection rate: 50 g/s Comparative example-1 When performing block copolymerization, except that nothing was added at the end of the first stage polymerization Example 1 was repeated under the same conditions.

As a result, 33.4 kg of product powder was obtained.

Details of the results are shown in Table 1.

Examples 2 to 4 Example 1 was repeated except that when carrying out block copolymerization, the weight ratio between the first stage polymerization and the second stage polymerization and the weight ratio of propylene and ethylene in the second stage polymerization were changed.

The results are shown in Table 1.

Example 5 Example 5 was repeated except that when carrying out block copolymerization, the additive used at the start of the first stage polymerization was changed from diphenyldimethoxysilane to 4.2 g of tert-butylmethyldimethoxysilane.

The results are shown in Table 1.

Example 6 (l) Preparation of solid catalyst component In a 500 ml glass trituron flask (with thermometer and stirring bar) purged with nitrogen, 75 ml of purified hebutane, 75 ff1 liter of titanium tetrabutoxide, and Log anhydrous were added. Add magnesium chloride. Then, add 9 flasks.
The temperature was raised to 0°C, and magnesium chloride was completely dissolved over 2 hours. Next, the flask was cooled to 40°C, and methylhydrodiene polysiloxane 151 was added to precipitate a magnesium chloride/titanium tetrabutoxide complex. This was washed with purified butane to obtain an off-white solid.

20% of the precipitated solid obtained above was placed in a 300 ml glass Mitsuro flask (with thermometer and stirring bar) purged with nitrogen.
A heptane slurry containing 651 g was introduced. Then,
251 parts of a heptane solution containing 8.71 parts of silicon tetrachloride was added over 30 minutes at room temperature, and the mixture was further reacted at 30°C for 30 minutes. The reaction was further carried out at 90°C for 1 hour, and after the reaction was completed, the reaction mixture was washed with purified butane. Then phthaloyl chloride 1.6
A heptane solution 501 containing 1 was added and reacted at 50°C for 2 hours, then washed with purified hebutane, titanium tetrachloride 251 was added and reacted at 90°C for 2 hours. This was washed with purified butane, and further tert-butylmethyldimethoxysilane 1. Og was added and the mixture was reacted at 30° C. for 2 hours to obtain a solid catalyst component. The titanium content in the solid catalyst component was 2.56% by weight.

(2) After sufficiently purging a stirred autoclave with a polymerization internal volume of 200 liters with propylene, 60 liters of dehydrated and deoxygenated n-hebutane was introduced, and triethylaluminum CB)
6.0 g, and the solid composition (A)3. Of70
It was introduced under a propylene atmosphere at °C.

The first-stage polymerization was started by heating the autoclave to 75° C. and then introducing propylene at a rate of 9 kg/hour while maintaining the hydrogen concentration at 2.5%.

After 215 minutes, the introduction of propylene was stopped and the polymerization was further continued for 7 minutes.
It was continued for 90 minutes at 5°C. Gas phase propylene 0.2
It was purged until it became kg/clrG.

Next, 6.8 g of tetra n-butyl titanate and 160 g of triethyl aluminum were added, and the autoclave was heated to 60 g.
After cooling down to ℃, the second stage polymerization was carried out using 1.57 kg of propylene/
8 hours at a feed rate of 2.35 kg/hour of ethylene
This was carried out by feeding for 7 minutes.

The results are shown in Table 1.

Example 7 (1) Preparation of solid catalyst component A solid catalyst component was prepared in the same manner as in Example 7 except that 1.5 g of norbornylmethyldimethoxysilane was used in place of tert-butylmethyldimethoxysilane.

(2) ffI match Example 7 was repeated.

The results are shown in Table 1.

Practical example 3 (1) Preparation of solid catalyst component A solid catalyst component was prepared in the same manner as in Example 7 except that 1.5 g of tert-butyltriethoxysilane was used in place of tert-butylmethyldimethoxysilane.

(2) Polymerization Example 7 was repeated. The results are shown in Table 1.

Comparative Example 2 Example 1 was repeated under the same conditions except that only 6.8 g of tetra n-butyl titanate was added at the end of the first stage polymerization when performing block copolymerization.

The results are shown in Table 1.

Comparative Example 3 Example 1 was repeated under the same conditions except that only 1.0 g of triethylaluminum was added at the end of the first stage polymerization when performing block copolymerization.

The results are shown in Table 1.

Claims (1)

[Claims] In the presence of a Ziegler-type catalyst formed from (A) a solid titanium catalyst component containing magnesium, titanium, halogen, and an electron donor as essential components and (B) an organoaluminum compound, propylene is crystallized independently in the previous step. A polymer or copolymer is produced, and in a later step propylene and ethylene are mixed in the coexistence of the homopolymer or copolymer at a polymerization ratio (molar ratio) of 0/100 to 80/20.
A method for producing a propylene block copolymer, which comprises adding an alkoxytitanium compound and an organoaluminium compound during the latter stage polymerization.