JPH0826108B2 - Method for producing propylene block copolymer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION Technical Field The present invention relates to a method for producing a propylene block copolymer having 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 simply referred to as polypropylene) was produced in the first stage, and then in the second stage. To produce a rubbery copolymer of propylene by copolymerizing propylene with other α-olefin in the presence of the polypropylene, and /
Alternatively, it is known to produce crystalline homopolymers or copolymers of other α-olefins, in particular ethylene or ethylene-based crystalline homopolymers or copolymers. It is known that a composition having improved impact resistance at low temperature can be obtained by such a multi-stage polymerization method while maintaining the excellent rigidity of polypropylene.

This composition is usually an intimate mixture of homopolymers or copolymers produced at each stage, but is generally referred to as a block copolymer. Such block copolymers are often used in, for example, containers, automobile parts, easily low temperature heat sealable films, and high impact resistant films.

As a catalyst for producing such a block copolymer, a titanium trichloride-type catalyst has been conventionally used,
This requires a catalyst removal step, that is, a detouching step because the catalyst activity is low.

In recent years, many methods using a carrier type catalyst have been proposed as a method for greatly improving the activity before the detouching step becomes unnecessary (JP-A-52-98045, JP-A-53-88049, JP-A-53-88049). 58-83016, etc.)

However, the carrier-type catalyst has a smaller molecular weight in the subsequent copolymerized portion than the conventional titanium trichloride-type catalyst, so the molecular weight distribution of the block copolymer is narrow, and the moldability during processing (spiral flow) is deteriorated. There was a problem of doing.

The present inventors have already found that 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, the moldability during processing can be significantly improved. We have conducted diligent studies for further improvement.

On the other hand, for the purpose of improving the adhesion of polymer particles, a method of adding an electron-donating compound at the initiation of the second-stage polymerization has recently been proposed (JP-A-61-69821, 61-69822, 61-69823).
No. Bulletins, etc.).

However, it has been difficult to improve the moldability of the block copolymer with these additives.

[Outline of Invention]

The present invention aims to provide a solution to the above problems, and when carrying out block copolymerization using a carrier-type catalyst, by adding a specific additive at the end of the first-stage polymerization, It significantly improves the moldability.

That is, the method for producing a propylene block copolymer according to the present invention comprises a Ziegler formed from (A) a solid titanium catalyst component containing magnesium, titanium, halogen and an electron donor as essential components and (B) an organoaluminum compound. A crystalline propylene homopolymer or copolymer is produced in the previous step in the presence of a catalyst of the type, and the polymerization ratio (molar ratio) of propylene and ethylene in the subsequent step in the presence of the homopolymer or the copolymer. Ratio) 0/100 to 80 /
In the method for producing a propylene block copolymer, which comprises polymerizing at a ratio of 20, the latter-stage polymerization is 1 to 1000 mol of cyclopentadienyl group or substituted cyclopentadienyl group per 1 mol of titanium in the component (A). The present invention is carried out in the presence of a tetravalent organic titanium compound having an indenyl group or a fluorenyl group.

Effect By producing a propylene block copolymer by the method of the present invention, it was possible to obtain a propylene block copolymer having high rigidity, high impact strength and excellent moldability using a carrier-type highly active catalyst. .

[Specific Description of the Invention]

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

Here, "formed from the component (A) and the component (B)" means that the third component which does not unduly impair the effects of the present invention or more preferably the third component which advantageously acts on the present invention. It should be understood that this does not exclude the case of including. A typical example of such a third component is an electron-donating compound (component (C)) as a so-called external donor, and the catalyst formed from components (A), (B) and (C) is It constitutes a preferred embodiment of the present invention.

It can be said that the catalyst of the present invention further contains a specific electron donor compound, that is, a specific tetravalent organic titanium compound as a so-called external donor in the latter stage of block copolymerization.

Component (A) The solid titanium catalyst component (A) used in the present invention comprises:
It contains magnesium, titanium, halogen and an electron donor as essential components. Here, "to be an essential component" means that, in addition to the case where the solid titanium catalyst component (A) is composed of only these specific three components, at least the effect of the combination of these three components is maintained or It means that additional components may be included unless they are unduly compromised. Such additional components are, for example, silicon halide compounds.

It is usual to introduce magnesium into component (A) by magnesium halide, titanium by titanium halide and halogen by 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, more preferably substantially anhydrous.

In addition, magnesium halide is magnesium oxide, magnesium hydroxide, hydrotalcite, magnesium carboxylate, alkoxymagnesium, allyloxymagnesium, alkoxymagnesium halide, allyloxymagnesium halide, organomagnesium compound electron donor, halosilane, Alkoxysilane, silanol, Al compound, titanium halide compound,
It may be magnesium halide obtained by treating with titanium tetraalkoxide or the like.

(2) Titanium Halide Titanium halide is typically a halogen compound of trivalent and tetravalent titanium. A preferable halogenated compound of titanium is represented by the general formula Ti (OR ¹ ) _n X _4-n (R ¹ is C _{1 to} C ₁₀
Hydrocarbon residue, X is a halogen), and is a tetravalent titanium halide compound with n = 0, 1 or 2 among compounds represented by Specifically, TiCl ₄ , Ti (OBu) Cl ₃ , Ti (OBu)
₂ Cl _{2 and the} like can be exemplified, but particularly preferable is
It is a titanium tetrahalide or a monoalkoxytrihalogenated titanium compound such as TiCl ₄ and Ti (OBu) Cl ₃ .

(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 (d). Among these, the compound (c) is particularly preferred.

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

Here, R ⁵ is a substituted or unsubstituted hydrocarbon group,
R ² , R ³ and R ⁴ are hydrogen or a substituted or unsubstituted hydrocarbon group, R ⁶ and R ⁷ are hydrogen or a substituted or unsubstituted hydrocarbon group, preferably at least one of which is substituted or An unsubstituted hydrocarbon group. R ³
And R ⁴ may be linked to each other. Here, the substituted hydrocarbon group includes a hetero atom such as N, O and S, for example, COC, COOR, COOH, OH, SO ₃ H, -CNC-, N
Some have groups such as H ₂ .

Particularly preferred among these are diesters of dicarboxylic acids in which at least one of R ⁵ and R ² is an alkyl group having 2 or more carbon atoms.

Specific examples of preferable polycarboxylic acid esters include (a) diethyl succinate, dibutyl succinate, diethyl methylsuccinate, diisobutyl α-methylglutarate, dibutyl methylmalonate, diethyl malonate, diethyl ethylmalonate, isopropyl. Diethyl malonate, diethyl butylmalonate, diethyl phenylmalonate, diethyl diethylmalonate, diethyl allylmalonate, diethyl diisobutylmalonate, diethyl dinormal butylmalonate, dimethyl maleate, monooctyl maleate, dioctyl maleate, maleic acid Dibutyl, butyl maleic acid dibutyl, butyl maleic acid diethyl, β-methyl glutarate diisopropyl, ethyl succinate diaryl, di-2-ethylhexyl fumarate, diethyl itaconate, Aliphatic polycarboxylic acid esters such as dibutyl taconate, dioctyl citraconic acid, dimethyl citraconic acid, (b) diethyl 1,2-cyclohexanecarboxylate, diisobutyl 1,2-cyclohexanecarboxylate, diethyl tetrahydrophthalate, diethyl nadic acid Aliphatic polycarboxylic acid esters, such as
(C) Monoethyl phthalate, dimethyl phthalate, methylethyl phthalate, monoisobutyl phthalate, mononormal butyl phthalate, diethyl phthalate, ethyl isobutyl phthalate, ethyl normal butyl phthalate, di-n-propyl phthalate, phthalate Diisopropyl acid, di-n-phthalate
Butyl, diisobutyl phthalate, di-n-heptyl phthalate, di2-ethylhexyl phthalate, di-n-octyl phthalate, dineopentyl phthalate, didecyl phthalate, benzyl butyl phthalate, diphenyl phthalate, diethyl naphthalene dicarboxylate, naphthalene Examples thereof include aromatic polycarboxylic acid esters such as dibutyl dicarboxylate, triethyl trimellitate and dibutyl trimellitate, and different carbon polycarboxylic acid esters such as (d) 3,4-furandicarboxylic acid.

Further, specific examples of preferable polyhydric hydroxy compound esters include 1,2-diacetoxybenzene and 1-
Examples thereof include methyl-2,3-diacetoxybenzene, 2,3-diacetoxynaphthalene, ethylene glycol dipivalate and butanediol pivalate.

Examples of hydroxy-substituted carboxylic acid esters include:
Benzoyl ethyl salicylate, acetyl isobutyl salicylate, acetyl methyl salicylate and the like can be exemplified.

Other examples of polycarboxylic acid ester that can be supported in the titanium catalyst component, diethyl adipate, diisobutyl adipate, diisopropyl sebacate, di-n-butyl sebacate, di-n-octyl sebacate,
Mention may be made of long-chain dicarboxylic acid esters such as di-2-ethylhexyl sebacate.

Among these polyfunctional esters, those having a skeleton of the above-mentioned general formula are preferable, and more preferable are phthalic acid, maleic acid, substituted malonic acid, etc. and C 2
The above esters with alcohols, particularly preferred are diesters of phthalic acid and alcohols having 2 or more carbon atoms.

(B) Still another group of the electron-donor component which is an essential component of the solid catalyst component (A) is R ⁸ COOR ⁹ (R ⁸ and R ⁹ have 1 to 15 carbon atoms).
A hydrocarbyl group of a degree, at least one of which is a branched (including alicyclic) or ring-containing chain group) monocarboxylic acid ester. Examples of R ⁸ and / or R ⁹ include (CH ₃ ) ₂ CH-, C ₂ H _{5
CH (CH 3) -, (} CH 3) 2 CHCH 2 -, (CH 3) 3 C-, C 2 H 5 CH (CH 3) CH
_2- , And the like. If one of R ⁸ and R ⁹ is a branched group as described above, the other may be the above group or another group such as a linear or cyclic group.

Examples of such monocarboxylic acid esters include various monoesters of α-methylbutyric acid, β-methylbutyric acid, methacrylic acid, benzoylacetic acid and the like, and various monocarboxylic acid esters of alcohols such as isopropanol, isobutyl alcohol and tertiary butyl alcohol. It can be illustrated.

Carbonates can also be selected as the electron donor (c).

Specific examples of the carbonic acid ester include diethyl carbonate, ethylene carbonate, diisopropyl carbonate, phenylethyl carbonate and diphenyl carbonate.

(D) The electron donor component (d) is a compound having a structural site represented by the following formula in its molecule.

(Wherein R ¹⁰ is a hydrocarbon residue having 1 to 12 carbon atoms, or In the above structure, R ¹⁰ is preferably a relatively short chain unbranched hydrocarbon residue having 1 to 4 carbon atoms, and The carbons of are preferably unbranched carbon atoms. In addition, as this compound, a compound having no polar atom such as O, S and N in a portion other than the above-mentioned specific structure is generally used.

Furthermore, this compound is It is preferable to have one structure of 1 in the molecule.

Preferred among such compounds are those represented by the following formula (d ').

Here, R ¹⁰ is the same as R ¹⁰ in the formula indicates the R ^a and R ^b is 1 to carbon atoms, respectively 12, alkyl group, aryl group, alkyl-substituted aryl or aryl-substituted alkyl group. Among the compounds represented by the formula (d '), particularly preferred are lower aliphatic monocarboxylic acids (having R ^a of about 1 to 12 carbon atoms or benzoic acid (R ^a is a phenyl group) ethylene oxide or propylene oxide). Addition (1
Mol) ether, especially lower (C ₁ -C ₁₂ ) alkyl or phenyl or tolyl ether.

Specific examples of such an electron donor compound (d) include, for example, 2-methoxyethyl acetate (CH ₃ CO ₂
CH ₂ CH ₂ OCH ₃ ), 2-ethoxyethyl acetate (CH ₃ CO ₂ CH ₂ CH ₂ OC ₂ H ₅ ), 2-butoxyethyl acetate (CH ₃ CO ₂ CH ₂ CH ₂ OC ₄ H ₉ ), 3-methoxybutyl = acetate _{(CH 3 CO 2 (CH 2} ) 2 CH (OCH 3) CH 3), 2- (2- ethoxyethoxy) ethyl = acetate _{(CH 3 CO 2 CH 2 CH} 2 OCH 2 CH 2 OC ₂ H ₅ ), 2-p-toloxyethyl acetate (CH ₃ CO ₂ (CH ₂ ) ₂ OC ₆ H ₄ (CH ₃ )), ethoxylmethyl acetate (CH ₃ CO ₂ CH ₂ OC ₂ H ₅ ). , 3-ethoxypropyl acetate (CH ₃ CO ₂ CH ₂ CH ₂ CH ₂ OC ₂ H ₅ ), 4-ethoxybutyl acetate (CH ₃ CO ₂ (CH ₂ ) ₄ OC ₂ H ₅ ), n-butylcarbi Tol = acetate (CH ₃ CO ₂ (CH ₂ CH ₂ O) ₂ O ₄ H ₉ ), 2-butoxyethyl propionate (CH ₃ CH ₂ CO ₂ CH ₂ CH ₂ OC ₄ H ₉ ), 2-isobutoxyethyl = Propionate (CH ₃ CH ₂ CO ₂ (CH ₂ ) ₂ OCH ₂ CH (C H _{3) 2),} 2- ethoxyethyl = n-butyrate _{(C 4 H 9 CO 2 CH} 2 CH 2 OC 2 H 5), 2- ethoxyethyl = isobutyrate _{(CH 3) 2 CHCO 2 CH} 2 CH 2 OC 2 H ₅ ), 2-ethoxyethyl benzoate (C ₆ H ₅ CO ₂ CH ₂ CH ₂ OC ₂ H ₅ ), 2-isopropoxyethyl benzoate (C ₆ H ₅ CO ₂ CH ₂ CH ₂ OCH (CH ₃ ). _2), p-methoxybenzyl = acetate _{(CH 3 CO 2 CH 2 -C} 6 H 4 OCH 3), 4'- ethoxyphenyl = 4-n-butylbenzoate _{(CH 3 (CH 2) 3} C 6 H 4 CO _{2 C 6 H 4 OC 2 H} 4), tetrahydrofurfuryl = n-butyrate (CH ₃ (CH ₂₎ or the like _{2 CO 2 CH 2 (C 4} H 7 O). Among these, 2-ethoxyethyl = acetate and 2-methoxyethyl =
Acetate and the like are preferable.

(E) The organosilicon compound used as the component (c) described below can be used.

When incorporating these electron donor components into the solid catalyst component (A), it is not always necessary to use them as starting materials, and it is necessary to use compounds that can be converted to these in the process of preparing the solid catalyst components. It may be converted to these compounds in a step.

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

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

(B) A magnesium dihalide is dissolved using a hydrocarbon or a halogenated hydrocarbon as a solvent and an alcohol, a phosphoric ester or a titanium alkoxide as a dissolution promoter. Then, dissolved magnesium dihalide was added to this solution with a poor solvent, an inorganic halide,
An electron donor such as an ester or a polymer silicon compound such as methylhydrogenpolysiloxane is added and precipitated.

(C) The mono- or dialcoholate or magnesium carboxylate of magnesium is contacted with a halogenating agent.

(D) Catalytic reaction between magnesium oxide and chlorine or AlCl ₃ .

(E) A contact reaction between MgX ₂ .nH ₂ O (X is a halogen) and a halogenating agent or TiCl ₄ .

(F) Catalytic reaction of MgX ₂ · nROH (X is a halogen, R is an alkyl group) with a halogenating agent or TiCl ₄ .

(G) a Grignard reagent, a MgR ₂ compound (R is an alkyl group), or a complex of a MgR ₂ compound and a trialkylaluminum compound is used as a halogenating agent such as Al X ₃ , AlR _m X
_A catalytic reaction is carried out with _3-m (X is a halogen and R is an alkyl group), SiCl ₄ or HSiCl ₃ .

(H) contacting the Grignard reagent with silanol or with polysiloxane, H ₂ O or silanol,
After that, it is contacted with a halogenating agent or TiCl ₄ .

For details of such pretreatment of magnesium halide, see JP-B-46-611, JP-B-46-34092, and JP-B-51-351.
No. 4, No. 56-67311, No. 53-40632, No. 56-50888, No. 5
No. 7-48565, No. 52-36786, No. 58-449, JP-A-53-4568
No. 6, No. 50-126590, No. 54-31092, No. 55-135102,
No. 55-135103, No. 56-811, No. 56-11908, No. 57-1806
No. 12, No. 58-5309, No. 58-5310, and No. 58-5311 can be referred to.

The contact between the pretreated magnesium chloride, the titanium halide and the electron donor compound may be carried out by forming a complex of the titanium halide and the electron donor compound and then contacting the complex with the magnesium chloride. The contact may be performed by bringing magnesium chloride into contact with a titanium halide and then with an electron donor compound, or by bringing the magnesium chloride into contact with the electron donor compound and then contacting with a titanium halide.

The contact method may be pulverization contact such as a ball mill or a vibration mill, or magnesium chloride or an electron donor-treated product of magnesium chloride may be added to the liquid phase of titanium halide.

Washing with an inert solvent may be carried out after the contact with the three or four components or at an intermediate stage between the contact with the respective components.

The solid catalyst component (A) thus produced has a titanium halide content of 1 to 20% by weight, a magnesium halide content of 50 to 98% by weight, and a molar ratio of the electron donor compound to the titanium halide is It is about 0.05 to 2.0.

Component (B) an organoaluminum compound used in the present invention as component (B) has the general formula AlR _n X _3-n (wherein, R represents 1 to carbon atoms
12 hydrocarbon residues, X is a halogen or alkoxy group,
n is preferably 0 <n ≦ 3).

Such an organoaluminum compound is specifically,
For example, triethyl aluminum, tri-n-propyl aluminum, tri-n-butyl aluminum, triisobutyl aluminum, tri-n-hexyl aluminum,
Triisohexyl aluminum, trioctyl aluminum, diethyl aluminum hydride, diisobutyl aluminum hydride, diethyl aluminum monochloride, ethyl aluminum sesquichloride,
Examples include diethylaluminum monoethoxyside.
Of course, two or more of these organoaluminum compounds can be used in combination.

The use ratio of the organoaluminum compound (B) and the solid catalyst component (A) used in the polymerization of α-olefin can be varied within a wide range, but in general, it is 1 to 1000, preferably 1 to 1000 per titanium atom contained in the solid catalyst component. Is 10 ~
An organoaluminum compound can be used at a ratio of 500 (molar ratio).

Component (C) In the block copolymer of the present invention, various electron donors can be used as needed. As the electron donor, ethers, peroxides, amines, organic silicon compounds and the like are preferably used. Specific examples are shown below.

(A) Ether compound One example of the ether used in the present invention is a compound represented by the general formula Is an ether represented by. In the formula, R ^{11 to} R ¹³ are saturated or unsaturated hydrocarbon residues and generally have 1 carbon atoms.
To C10, preferably C1 to C4 alkyl or alkenyl groups (including substituted derivatives substituted with halogen or phenyl), or C6 to C12, preferably C6 to C10. , A phenyl group (including a halogen, an alkyl group (particularly, a lower alkyl group) or a substituted derivative with a phenyl group). However, among R ^{11 to} R ¹³ , 1 to
Two are phenyl groups (including substituted derivatives with halogen or alkyl groups (especially lower alkyl groups)). R
¹⁴ is a hydrocarbon group. Specific examples of such ether compounds include α-cumylmethyl ether, α-cumylethyl ether, 1,1-diphenylethylmethyl ether, 1,1-diphenylethylethyl ether, α-cumyl tert-butyl ether. , Di-α-cumyl ether, 1,1-ditolylethyl methyl ether, 1,1-ditolylethyl ethyl ether, bis (1,1-ditolylethyl) ether, 1-tolyl-1-methylethyl methyl ether, etc. .

Besides, ether compounds such as 1,4-cineole, 1,8-cineole and meta-cineole can also be used.

(B) Peroxide The peroxide used in the present invention is a compound represented by the following formula.

(In the formula, R ^{15 to} R ¹⁸ are saturated or unsaturated hydrocarbon groups, and R ¹⁸ is a hydrocarbon group containing or not containing oxygen atoms.) Specific examples of R ^{15 to} R ¹⁸ include the number of carbon atoms. It is an aliphatic or aromatic hydrocarbon of about 1 to 20. Specific examples of R ¹⁸ include R ^{15 to} R ¹⁸
Of the above hydrocarbons and ether oxygen or carbonyl oxygen introduced therein.

Specific examples of such compounds include 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane,
1,1-bis (tertiary butylperoxy) cyclohexane, di-tertiary butyl peroxide, tert-butyl cumyl peroxide, di-cumyl peroxide, bis (1,1-diphenylethyl) peroxide, 2,5- Examples thereof include dimethyl-2,5-di (tertiary butylperoxy) hexane.
Preferred are di-cumyl peroxide and bis (1,
1-diphenylethyl) peroxide.

(C) Amine Compound The amine compound used in the present invention is a sterically hindered amine such as 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetraethylpiperidine.

(C) Organosilicon Compound As a specific example of the organosilicon compound used in the present invention, dialkoxy or trialkoxysilane is preferably used. A specific example is represented by the following structural formula.

_{(CH 3) 3 C-Si} (OCH 3) 3 (CH 3) 3 C-Si (OC 2 H 5) 3 (C ₂ H ₅ ) ₃ C-Si (OC ₂ H ₅ ) ₃ The molar ratio of the component (C) electron donor to the component (B) organoaluminum compound is usually 0.01 to 1.0, preferably 0.02.
~ 0.5.

Block Copolymerization The polymerization step of the present invention performed in the presence of the catalyst is a pre-stage polymerization for producing a crystalline homopolymer or copolymer of propylene, and a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group. Alternatively, it comprises two stages of post-stage polymerization in which propylene and ethylene are polymerized at a polymerization ratio (molar ratio) of 0/100 to 80/20 in the presence of a tetravalent organic titanium compound having a fluorenyl group.

Here, the term "performing the post-stage polymerization in the presence of the organotitanium compound" means that a substantial part of the post-stage polymerization is conducted in the presence of the organotitanium compound. This means that the addition operation itself is carried out after the latter half of the first-stage polymerization, particularly after the substantial end thereof and until the first half of the latter-stage polymerization, particularly before the substantial end thereof.

First-stage polymerization In the first-stage polymerization, propylene alone or a propylene / ethylene mixture is mixed with the catalysts (A) and (B) and, if necessary, (C).
And a propylene homopolymer or a propylene / ethylene copolymer having an ethylene content of 7% by weight or less, preferably 1.0% or less, in one stage or in multiple stages, and 50 to 95% by weight of the total polymerization amount. %, Preferably 60 to 90% by weight.

When the ethylene content in the propylene / ethylene copolymer is further increased in the first-stage polymerization, the bulk density of the final copolymer is lowered, and the amount of by-products of the low crystalline polymer is significantly increased. Further, even when 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 large also occurs. On the other hand, if the polymerization ratio exceeds the above range, the amount of by-products of the low crystalline polymer tends to decrease, but the impact strength, which is the purpose of block copolymerization, is undesirably reduced.

The polymerization temperature in the first-stage polymerization is 30 to 90 ° C, preferably 50 to 80
℃, about. The polymerization pressure is about 1 to 30 kg / cm ² .

In the first-stage polymerization, it is preferable to use a molecular weight regulator so that the final polymer has an appropriate fluidity, and hydrogen is preferably used as the molecular weight regulator.

Addition of Organotitanium Compound The organotitanium compound to be present in the second-stage polymerization is a specific compound belonging to a compound having a hydrocarbon group having a σ bond or a π bond to a titanium atom, preferably a π bond. Alkoxytitanium compounds are not used in the present invention.

This particular organotitanium compound used in the present invention is
It is a tetravalent organic titanium compound having a cyclopentadienyl group or a substituted cyclopentadienyl group. Examples of such compounds include bis (cyclopetadienyl) titanium dichloride, bis (cyclopentadienyl) titanium dimethyl, bis (cyclopentadienyl) titanium diphenyl, bis (cyclopentadienyl) Ti = CH ₂ .Al. (CH ₃ ) ₂ C
l, bis (indenyl) titanium diphenyl, bis (indenyl) titanium dichloride, bis (methylcyclopetadienyl) titanium diphenyl, bis (methylcyclopentadienyl) dichloride, bis (1,2-dimethylcyclopentadienyl) titanium Diphenyl, bis (fluorenyl) titanium dichloride, bis (1,2-diethylcyclopentadienyl) titanium diphenyl, dimethylsilyldicyclopentadienyl titanium diphenyl, methylphosphine dicyclopentadienyl titanium dichloride, methylenedicyclopenta Dienyl titanium diphenyl etc. can be mentioned.

Of these, the cyclopentadienyl derivative is preferable. The term "cyclopentadienyl" when referred to herein as a cyclopentadienyl derivative includes cyclopentadiene substituted by cyclo lower alkyl, for example, methyl or ethyl, and such lower alkyl substitution or Unsubstituted cyclopentadiene moieties include those linked by lower alkylene, such as methylene or ethylene.

The organotitanium compound is usually added in an amount of 1-1000 mol, preferably 10-100 mol, per 1 mol of titanium in the component (A).

The organotitanium compound may be added during the first-stage polymerization or during the second-stage polymerization. The preferred timing of addition is at the end of the first-stage polymerization or at the start of the second-stage polymerization.

Second-stage polymerization In the second-stage polymerization, propylene /
An ethylene mixture is further introduced to give an ethylene content of 20 to 10
0% by weight, preferably 30 to 100% by weight, more preferably 75
This is a step of obtaining a propylene / ethylene copolymer of up to 95% by weight in one or more stages. In this step, it is desirable to form an amount corresponding to 5 to 50% by weight, preferably 10 to 40% by weight of the total amount of the polymer.

If the polymerization ratio of the second-stage polymerization and the composition of the propylene / ethylene mixture are less than the above ranges, the impact resistance (particularly, low-temperature impact resistance) is poor, and the effect of improving the spiral flow is small. On the other hand, when the amount exceeds the above range, operational problems such as a large increase in the amount of the low crystalline polymer by-produced and a remarkable increase in the viscosity of the polymerization solvent occur.

In the second-stage polymerization, a small amount of another comonomer may coexist. Examples of such comonomers include α-olefins such as 1-butene, 1-pentene and 1-hexene.

The polymerization temperature of the second-stage polymerization is 30 to 90 ° C, preferably 50 to 80
℃, about. The polymerization pressure is about 1 to 30 kg / cm ² .

At the time of shifting from the first-stage polymerization to the second-stage polymerization, it is preferable to purge the propylene gas or the propylene / ethylene mixed gas and the hydrogen gas derived from the first-stage polymerization and shift to the second-stage polymerization.

In the latter polymerization, the molecular weight regulator may or may not be used according to the purpose. That is, when it is desired to increase the impact resistance of the final polymer, this step is preferably performed in the substantial absence of a molecular weight modifier.

Polymerization method The method for producing the copolymer according to the present invention is a batch method, a continuous method,
It can be carried out by any of the semi-batch methods. At this time, a method in which polymerization is performed in an inert hydrocarbon solvent such as heptane, a method in which the monomer used is used as a medium, and a method in which polymerization is performed in a gaseous monomer without using a medium , And a method in which these are combined can be adopted. The first-stage polymerization and the second-stage polymerization may be carried out in separate polymerization tanks.

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

Experimental Example Example-1 (1) Preparation of solid catalyst component A glass three-necked flask (with a thermometer and a stir bar) with a nitrogen displacement of 500 ml and having an inner volume of 500 ml, 75 ml of purified heptane and 75 ml
Of titanium tetrabutoxide and 10 g of anhydrous magnesium chloride. Thereafter, the temperature of the flask was raised to 90 ° C., and magnesium chloride was completely dissolved over 2 hours. The flask was then cooled to 40 ° C and magnesium chloride
A titanium tetrabutoxide complex was precipitated. This was washed with purified heptane to obtain an off-white solid.

65 ml of a heptane slurry containing 20 g of the precipitated solid obtained above was introduced into a 300-ml glass three-necked flask (with a thermometer and a stirring bar) having a 300 ml internal volume purged with nitrogen. Next, 25 ml of a heptane solution containing 8.7 ml of silicon tetrachloride was added over 30 minutes at room temperature, and further reacted at 30 ° C. for 30 minutes. 90 ° C
After reacting for 1 hour, the reaction mixture was washed with purified heptane after completion of the reaction. Then heptane solution containing 1.6 ml of phthaloyl chloride 5
0 ml was added and the mixture was reacted at 50 ° C. for 2 hours, then washed with purified heptane, 25 ml of titanium tetrachloride was further added, and the mixture was reacted at 90 ° C. for 2 hours. This was washed with purified heptane to obtain a solid catalyst component. Titanium content in the solid catalyst component is 3.22
% By weight.

(2) Polymerization After thoroughly replacing the stirring autoclave with an internal volume of 200 liters with propylene, dehydrated and deoxygenated n-heptane 60
Introduced liter, triethyl aluminum (B) 15.0
g, 3.0 g of the solid composition (A) and 6.4 g of diphenyldimethoxysilane were introduced at 70 ° C. in a propylene atmosphere.

The first-stage polymerization was started by heating the autoclave to 75 ° C. and then introducing propylene at a speed of 9 kg / hour while maintaining the hydrogen concentration at 2.0%.

After 215 minutes, the introduction of propylene was stopped and the polymerization was continued for 75 minutes.
Continued at 90 ° C for 90 minutes. 0.2 kg / cm ^{2 of} propylene in the gas phase
Purge until G.

Next, after adding 2.5 g of bis (cyclopentadienyl) titanium chloride and cooling the autoclave to 60 ° C.,
The second-stage polymerization was carried out by feeding propylene at a feed rate of 1.57 kg / hour and ethylene at 2.35 kg / hour for 87 minutes.

The slurry thus obtained is excessively dried and dried.
36.3 kg of a powdery block copolymer was obtained.

 Details of the results are as shown in Table 1.

The weight ratio of 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) Physical property measurement (a) 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 following additives were blended with the powdery polymer obtained in each of the examples and comparative examples, and pelletized by an extruder under the same conditions, and a 4 mm-thick sheet was prepared by an injection molding machine. Then, physical properties were evaluated.

Additive 2,6-di-tert-butylphenol 0.10 wt% RA1010 (Ciba Geigy) 0.05 wt% Calcium stearate 0.10 wt% PTBBA-Al (Shell Chemical) 0.10 wt% Physical property measurements According to

(A) Flexural modulus: ASTM-D790 (b) Izod impact strength (0 ° C): ASTM-D256 (with notch) (c) Spiral flow measurement method Each machine SJ type (inline screw type) injection molding machine is used. It was measured under the following conditions with a mold having a cross section of 2 mm × 8 mm.

Molding temperature: 240 ℃ Injection pressure: 800kg / cm ² Injection time: 6 seconds Mold temperature: 40 ℃ Injection rate: 50g / second Comparative example-1 When performing block copolymerization, bis (cyclopentadiene) Example-1 was repeated, but without the addition of the (enyl) titanium dichloride. As a result, 33.4 kg of product powder was obtained.

 The details of the results are shown in Table 1.

Examples 2 to 4 Example 1 was repeated except that the weight ratio of the first-stage polymerization and the second-stage polymerization and the weight ratio of propylene and ethylene in the second-stage polymerization were changed when the block copolymerization was carried out. The results are shown in Table 1.

Examples 5 to 6 and Comparative Example 2 When performing block copolymerization, 2.2 g of bis (cyclopentadienyl) titanium dimethyl, 2.8 g of bis (cyclopentadienyl) titanium diphenyl or tetra as an additive at the end of the first-stage polymerization. Example-1 was repeated except that 2.0 g of ethoxy titanium was used.

 The results are shown in Table 1.

Example-7 In carrying out block copolymerization, Example was repeated except that the additive at the initiation of the first-stage polymerization was changed from diphenyldimethoxysilane to 4.2 g of tert-butylmethyldimethoxysilane.

 The results are shown in Table 1.

Example-8 (1) Preparation of solid catalyst component A glass three-necked flask (with a thermometer and a stir bar) having an inner volume of 500 ml replaced with nitrogen was charged with 75 ml of purified heptane and 75 ml.
Of titanium tetrabutoxide and 10 g of anhydrous magnesium chloride. Thereafter, the temperature of the flask was raised to 90 ° C., and magnesium chloride was completely dissolved over 2 hours. The flask was then cooled to 40 ° C and magnesium chloride
A titanium tetrabutoxide complex was precipitated. This was washed with purified heptane to give an off-white solid.

65 ml of a heptane slurry containing 20 g of the precipitated solid obtained above was introduced into a 300-ml glass three-necked flask (with a thermometer and a stirring bar) having a 300 ml internal volume purged with nitrogen. Next, 25 ml of a heptane solution containing 8.7 ml of silicon tetrachloride was added over 30 minutes at room temperature, and further reacted at 30 ° C. for 30 minutes. 90 ° C
After reacting for 1 hour, the reaction mixture was washed with purified heptane after completion of the reaction. Then heptane solution containing 1.6 ml of phthaloyl chloride 5
0 ml was added and the mixture was reacted at 50 ° C. for 2 hours, then washed with purified heptane, 25 ml of titanium tetrachloride was further added, and the mixture was reacted at 90 ° C. for 2 hours. This was washed with purified heptane, 1.0 g of tert-butylmethyldimethoxysilane was further 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) Polymerization After thoroughly replacing the stirring autoclave with an internal volume of 200 liters with propylene, dehydrated and deoxygenated n-heptane 60
Introduced liter, triethyl aluminum (B) 15.0
g, 3.0 g of the solid composition (A) and 6.4 g of diphenyldimethoxysilane were introduced at 70 ° C. in a propylene atmosphere.

The first-stage polymerization was started by heating the autoclave to 75 ° C. and then introducing propylene at a speed of 9 kg / hour while maintaining the hydrogen concentration at 2.0%.

After 215 minutes, the introduction of propylene was stopped and the polymerization was continued for 75 minutes.
Continued at 90 ° C for 90 minutes. 0.2 kg / cm ^{2 of} propylene in the gas phase
Purge until G.

Next, 2.5 g of bis (cyclopentadienyl) titanium dichloride was added, and the temperature of the autoclave was lowered to 60 ° C.
The second-stage polymerization was carried out by feeding propylene at a feed rate of 1.57 kg / hour and ethylene at 2.35 kg / hour for 87 minutes.

 The results are shown in Table 1.

[Brief description of drawings]

FIG. 1 is a flow chart for facilitating understanding of the technical content of the present invention relating to a Ziegler catalyst.

Front page continuation (72) Inventor Toshihiko Sugano 1 Toho-cho, Yokkaichi-shi, Mie Prefectural Resin Research Laboratory, Mitsubishi Petrochemical Co., Ltd. (56) Reference JP-A-57-111307 (JP, A)

Claims (1)

[Claims] 1. A method according to claim 1, wherein said Ziegler catalyst is formed from (A) a solid titanium catalyst component comprising magnesium, titanium, halogen and an electron donor as essential components and (B) an organoaluminum compound. A crystalline homopolymer or copolymer of propylene is produced, and in a later stage the polymerization ratio (molar ratio) of propylene and ethylene is 0/100 to 80/80 in the presence of the homopolymer or copolymer.
In the method for producing a propylene block copolymer, which comprises polymerizing at a ratio of 20, the latter-stage polymerization is 1 to 1000 mol of cyclopentadienyl group or substituted cyclopentadienyl group per 1 mol of titanium in the component (A). A method for producing a propylene block copolymer, which is carried out in the presence of a tetravalent organic titanium compound having an indenyl group or a fluorenyl group.