JPH0826100B2 - Manufacturing method of low crystalline ethylene copolymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a low crystalline ethylene-based copolymer. More specifically, the present invention relates to a method for producing a low crystalline ethylene copolymer having a narrow molecular weight distribution and composition distribution, and further relates to a method for efficiently producing the low crystalline ethylene copolymer using a highly active catalyst.

[Conventional technology]

Conventionally, low crystalline ethylene such as low crystalline ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene / 1-butene / non-conjugated diene copolymer As a method for producing a system-based copolymer, a method of performing copolymerization in the presence of a zirconium-based catalyst composed of a titanium compound and an organoaluminum compound, or a vanadium-based catalyst composed of a vanadium compound and an organoaluminum compound is widely adopted industrially. ing. Among these methods, the method using a titanium-based catalyst has a large polymerization activity, but generally the obtained copolymer has a wide molecular weight distribution and composition distribution, and a low molecular weight with a high α-olefin content in the copolymer. It contains a large amount of the polymer, and even if it is used for the purpose of a rubbery polymer, these low molecular weight products cause stickiness and blocking, and there is a drawback that it does not show sufficient performance.On the other hand, the method using a vanadium-based catalyst has a drawback. Although the molecular weight distribution and composition distribution of the obtained copolymer are narrow,
In general, there is a drawback that the polymerization activity is small, and a process such as removing the residual catalyst component from the produced copolymer was required.

Further, a catalyst comprising a transition metal compound and aluminoxane as a new highly active polymerization catalyst in the olefin polymerization method is disclosed in JP-A-58-19309, JP-A-59-95292, and JP-A-60-35005. , JP-A-60-35006,
It has been proposed in Japanese Patent Laid-Open Nos. 60-35007 and 60-35008. Among these prior arts, JP-A-58
-19309, JP60-35005, JP60-35
JP-A-006, JP-A-60-35007, JP-A-60-35008
The publication describes that the catalyst system can be applied to the copolymerization of ethylene and α-olefin, but when applied to the copolymerization of ethylene and α-olefin by any of the methods, per unit amount of catalyst However, none of them shows a method for producing a low crystalline ethylene / α-olefin copolymer having a narrow molecular weight distribution and a narrow composition distribution.

[Problems to be solved by the invention]

Therefore, in the field of producing a low crystalline ethylene copolymer, a method capable of efficiently producing a low crystalline ethylene copolymer having excellent polymerization activity and a narrow molecular weight distribution and composition distribution is strong. Is requested. The inventors of the present invention recognize that the prior art in the field of producing low crystalline ethylene copolymers is in the above-mentioned situation, and have low polymerization ethylene copolymers having excellent polymerization activity and narrow molecular weight distribution and composition distribution. As a result of examining a method capable of producing a coalescence, in the presence of a catalyst composed of a transition metal compound and a specific aluminoxane, it was found that the above object can be achieved by copolymerizing ethylene and α-olefin.
The present invention has been reached.

[Means for Solving Problems] and [Action] The present invention provides a catalyst comprising (A) a compound of a transition metal selected from the group consisting of zirconium, hafnium and vanadium, and (B) an aluminoxane. By copolymerizing ethylene and α-olefin in the presence of -50 to 200 ° C, the ethylene component is in the range of 20 to 85% by weight, the molecular weight distribution (w / n) is 2.5 or less, and crystallization is performed. The degree is 30% or less, the intrinsic viscosity [η] is in the range of 1.21 to 10 dl / g,
And the following formula (In the formula, P _E represents the content mole fraction of the ethylene component in the copolymer, P _P represents the content mole fraction of the α-olefin component in the copolymer, and P _EP represents the ethylene of the entire dyad chain. · alpha-B value represented by the olefin chain shows the proportion of) is satisfied co ethylene content in the polymer is in the 50 mole% or less _{1.0 + 0.3P E ≦ B ≦ 1} / (1-P E) And the ethylene content of the copolymer is 50
A method of producing a low crystalline ethylene copolymer for producing an ethylene copolymer in the range of 1.3-0.3 P _E ≦ B ≦ 1 / P _E at mol% or more is a gist of the invention. is there.

The transition metal compound (A) used as a catalyst constituent in the method of the present invention is a compound of a transition metal selected from the group consisting of zirconium, hafnium and vanadium, and the zirconium compound is particularly highly active. As a preferred form of the transition metal compound, a compound having a hydrocarbon group or a compound having a hydrocarbon group and a halogen atom is preferable, particularly preferably at least one, particularly preferably two hydrocarbon groups. And, it is preferably a transition metal compound having at least one, and particularly preferably two halogen atoms. As the hydrocarbon group, specifically, an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, or a neopentyl group,
Examples thereof include isopropenyl group, alkenyl group such as 1-butenyl group, cyclopentadienyl group, cycloalkadienyl group such as methylcyclopentadienyl group, aralkyl group such as benzyl group and neophyl group. , A cycloalkadienyl group is preferable, and a cyclopentadienyl group is particularly preferable. Specific examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms. Furthermore, specifically as a transition metal compound,
Bis (cyclopentadienyl) dimethyl zirconium,
Bis (cyclopentadienyl) diethyl zirconium,
Bis (methylcyclopentadienyl) diisopropylzirconium, bis (cyclopentadienyl) methylzirconium monochloride, bis (cyclopentadienyl)
Ethyl zirconium monochloride, bis (cyclopentadienyl) methyl zirconium monobromide, bis (cyclopentadienyl) methyl zirconium monobromide, bis (cyclopentadienyl) methyl zirconium monoiodide, bis (cyclopentadienyl) zirconium Difluoride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl)
Zirconium dibromide, bis (cyclopentadienyl) zirconium monochloride monohydride, zirconium compounds such as bis (cyclopentadienyl) zirconium diiodide, bis (cyclopentadienyl) dimethylhafnium, bis (cyclopentadienyl) Examples thereof include hafnium compounds such as methylhafnium monochloride and bis (cyclopentadienyl) hafnium dichloride, and vanadium compounds such as bis (cyclopentadienyl) vanadium dichloride and bis (cyclopentadienyl) vanadium monochloride.

Specific examples of the aluminoxane (B) as a catalyst constituent used in the method of the present invention include general formula [I] or general formula [II] (In the formula, R represents a hydrocarbon group and m represents an integer of 2 or more). In the aluminoxane, R is a hydrocarbon group such as a methyl group, an ethyl group, a propyl group and a butyl group, preferably a methyl group, an ethyl group, particularly preferably a methyl group, and m is an integer of 2 or more, Preferably 5
It is an integer of the above or above, particularly preferably 10 to 100, particularly preferably 25 to 100. The following method can be exemplified as a method for producing the aluminoxane.

(1) A method in which a trialkylaluminum is added to a hydrocarbon medium suspension liquid such as a compound containing adsorbed water or a salt containing water of crystallization, for example, copper sulfate hydrate or aluminum sulfate hydrate to react.

(2) A method in which water is allowed to act directly on a trialkylaluminum in a medium such as benzene, toluene, ethyl ether, or tetrahydrofuran.

Among these methods, the method (1) is preferably adopted. The aluminoxane may contain a small amount of organic metal component.

FIG. 1 shows a step of preparing a catalyst used in the method of the present invention.

In the method of the present invention, the raw material supplied to the polymerization reaction system is a mixture of ethylene and α-olefin other than ethylene, and a chain non-conjugated polyene can be copolymerized if necessary. The content of ethylene in the polymerization raw material olefin is usually 10 to 80 mol%, preferably 20 to
70 mol%, the content of the α-olefin is usually 20 to
90 mol%, preferably in the range of 30 to 80 mol%,
Further, the content of the raw material olefin in the case of copolymerizing a chain non-conjugated polyene is usually 0 to 50 mol%, preferably 0 to 30 mol%. Therefore, the polymerization raw material olefin may be a mixture of ethylene and α-olefin, or a mixture of ethylene, α-olefin and a chain non-conjugated polyene.

Specific examples of α-olefins other than ethylene used as a raw material for polymerization in the method of the present invention include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1 -Dodecene, 1-
Tetradecene, 1-hexadecene, 1-octadecene,
An example is α-olefin having 3 to 20 carbon atoms such as 1-eicosene. Further, as the chain non-conjugated polyene supplied to the reaction system as necessary, specifically, 1,4-hexadiene, 1,5-hexadiene, 1,4-pentadiene,
1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4
-Hexadiene etc. can be illustrated.

In the method of the present invention, the olefin polymerization reaction is usually carried out in a hydrocarbon medium. Specific examples of the hydrocarbon-based medium include aliphatic hydrocarbons such as butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane, and octadecane, and cycloaliphatic rings such as cyclopentane, methylcyclopentane, cyclohexane, and cyclooctane. In addition to group hydrocarbons, aromatic hydrocarbons such as benzene, toluene, and xylene, petroleum fractions such as gasoline, kerosene, and light oil, raw material olefin is also a hydrocarbon medium. Of these hydrocarbon media, aromatic hydrocarbons are preferred.

In the method of the present invention, a liquid phase polymerization method such as a turbidity polymerization method or a solution polymerization method is usually adopted, and a solution polymerization method is particularly preferably adopted. The temperature during the polymerization reaction is in the range of -50 to 200 ° C, preferably -30 to 100 ° C, particularly preferably -20 to 80 ° C.

The ratio of the transition metal compound used when the method of the present invention is carried out by a liquid phase polymerization method is usually 10 ^-8 to 10 ^-2 gram atom / l as the concentration of transition metal atoms in the polymerization reaction system, preferably It is in the range of 10 ^-7 to 10 ^-3 gram atom / l. The aluminoxane content is usually 10 ^-4 to 10 ^-1 gram atom as the concentration of aluminum atoms in the polymerization reaction system.
/ l, preferably in the range of 10 ^-3 to 5 × 10 ^-2 gram atom / l, and the ratio of aluminum metal atom to transition metal atom in the polymerization reaction system is usually 4 to 10 ⁷ , preferably 10 to 10 It is in the range of 10 ⁶ . The molecular weight of the copolymer can be adjusted by hydrogen and / or the polymerization temperature.

In the method of the present invention, the low-crystalline ethylene copolymer is obtained by treating the polymerization reaction mixture after completion of the polymerization reaction by a conventional method. The composition of the low crystalline ethylene copolymer is such that the ethylene component is 20 to 85% by weight, preferably 30 to 80% by weight, the α-olefin component is 15 to 80% by weight, preferably 20 to 70% by weight and 0 to 30% by weight of conjugated polyene component, preferably 0 to
It is in the range of 20% by weight. The low crystalline ethylene copolymer is low crystalline or amorphous and has a crystallinity of 30% or less, preferably 20% or less, as determined by X-ray diffraction.
It is particularly preferably in the range of 0 to 15%. The molecular weight distribution (Mw / Mn) of the low crystalline ethylene copolymer measured by gel permeation chromatography (GPC) is 2.5 or less, preferably 2.2 or less, particularly preferably 2.0 or less. Is. When the molecular weight distribution of the low crystalline ethylene copolymer is larger than 2.5, the copolymer or the composition containing the copolymer as a modifier becomes more sticky or blocks. Must be in range. The B value, which is a parameter representing the composition distribution defined by the method described later of the low crystalline ethylene copolymer, is usually 1.0 + 0.3 × P _{E when} the ethylene content of the copolymer is 50 mol% or less. ≦ B ≦ 1 / (1-P _E ), preferably the general formula 1.0 + 0.4 × P _E ≦ B ≦ 1 / (1-P _E ), particularly preferably the general formula 1.0 + 0.5 × P _E ≦ B ≦ 1 / (1-P _E ), when the ethylene content of the copolymer is 50 mol% or more, the general formula is 1.3-0.3 × P _E ≦ B ≦ 1 / P _E , preferably the general formula Formula 1.4-0.4 x P _E ≤ B ≤ 1 / P _E , particularly preferably the general formula 1.5-0.5 x P _E ≤ B ≤ 1 / P _E (where P _E is the ethylene mole fraction of the copolymer). ).

The intrinsic viscosity [η] of the low crystalline ethylene copolymer measured in decalin at 135 ° C. is usually 0.01 to 20 dl / g, preferably 0.5 to 10 dl / g, more preferably 1.21 to 10 dl / g.
It is in the range of g.

The composition distribution of the low crystalline ethylene copolymer obtained by the method of the present invention is reported by GJ Ray et al. (Macromlecules 1
0 , 773 (1977)), the amount of ethylene units (E), the amount of α-olefin units (P) and the amount of dyad chains (EE, EP, PP) in the polymer are determined, and the amount of each monomer in the copolymer chain is calculated. The following values were defined as parameters showing the distribution state.

P _E and P _P are the mole fractions of ethylene and α-olefin
P _E ＋ P _P ＝ 1 P _EP is the ratio of all dyad chain EP chains P _EP ＝ EP / (EE ＋ EP ＋ PP) The larger the above B value, the fewer blocky chains and the more uniform distribution of ethylene and α-olefin. Yes Indicates that the copolymer has a narrow composition distribution. The composition distribution B value was determined by ¹³ C-NMR of a sample in which about 200 mg of the copolymer was uniformly dissolved in 1 ml of hexachlorobutadiene in a 10 mmφ sample tube.
Was obtained from the spectrum of The measurement conditions are shown below. Measurement temperature 120 ℃, measurement frequency 25.05MHz, spectrum width 1500H
z, filter width 1500Hz, pulse repetition time 4.2sec,
Pulse width 7 μsec, integration count 1000 times.

〔The invention's effect〕

According to the method of the present invention, there is a feature that a low crystalline ethylene copolymer having excellent polymerization activity and having a narrow molecular weight distribution and a narrow composition distribution can be efficiently produced. The ethylene-based copolymer has excellent performance as a rubber-like polymer. Further, the composition obtained by blending the low crystalline ethylene copolymer obtained by the method of the present invention as a modifier in a thermoplastic resin such as polyolefin is a composition obtained by blending a conventional low crystalline ethylene copolymer. It is characterized by less stickiness on the surface and less blocking property than objects.

〔Example〕

Next, the method of the present invention will be specifically described with reference to examples.

Example 1 Al ₂ (SO ₄ ) ₃ was added to a 200 ml flask that had been thoroughly purged with argon.
・ 14H ₂ O 7.4g and toluene 25ml were charged, trimethylaluminum 100mmol diluted with toluene 25ml after cooling to 0 ° C.
Was dripped. After completion of the dropping, the temperature was raised to 40 ° C. and the reaction was carried out at that temperature for 30 hours. After the reaction, solid-liquid separation was performed by filtration, and the separated liquid was used as an aluminoxane solution for polymerization. Toluene was partially removed from the separated liquid to prepare a sample for molecular weight measurement. The molecular weight determined by freezing point depression in benzene is 1650.
And the m value of the aluminoxane was 26.

Polymerization After charging 250 ml of purified toluene into a glass autoclave having an internal volume of 500 ml, a mixed gas of ethylene and propylene (50 l / hr and 50 l / hr, respectively) was circulated and kept at 20 ° C for 10 minutes. Then, aluminoxane equivalent to 0.5 milligram atom in terms of aluminum atom, dissolved in toluene corresponding to 1.25 × 10 ^-3 milligram atom in terms of zirconium atom (π-C ₅ H ₅ ) ₂ ZrCl ₂ was charged, Polymerization started. Polymerization was carried out at 20 ° C. for 1 hour in a flow system. After 1 hour, isopropyl alcohol was added to terminate the polymerization. Transfer the polymer solution into a large amount of methanol-acetone mixture,
The precipitated polymer was dried under reduced pressure at 130 ° C for 12 hours. Ethylene content 68% by weight, [η] 1.22 dl / g, crystallinity 0%,
12.5 g of a rubber-like polymer having a w / n of 1.83 and a B value of 1.22 was obtained. The activity per unit zirconium is 10,000 g polymer /
It was milligram atom-Zr.

Example 2 In Example 1, ethylene was added at 60 l / hr and propylene was added.
Polymerization was carried out in the same manner as in Example 1 except that 40 l / hr was supplied. The results are shown in Table 1.

Example 3 In Example 1, ethylene was added at 70 l / hr and propylene was added.
Polymerization was carried out in the same manner as in Example 1 except that 30 l / hr was supplied. The results are shown in Table 1.

Example 4 In the synthesis of aluminoxane, the reaction time was set to 4 days, and the aluminoxane component (white solid) was further extracted from the separated liquid.
Was isolated and redissolved in toluene and used for polymerization. The molecular weight determined by freezing point depression in benzene was 2700, and the m value of the aluminoxane was 45.

Polymerization After charging 250 ml of purified toluene into a glass autoclave having an internal volume of 500 ml, a mixed gas of ethylene and propylene (60 l / hr and 40 l / hr, respectively) was circulated and kept at 20 ° C for 10 minutes. Thereafter, the aluminoxane corresponding to 1.25 milligram atoms of aluminum atom in terms was dissolved in toluene which corresponds to 1.25 × 10 ^-3 mg atom in terms of zirconium atom _{(π-C 5 H 5)} 2 ZrCl 2 was charged with , The polymerization was started. Polymerization was carried out at 20 ° C. for 30 minutes in a flow system. The subsequent operation was performed in the same manner as in Example 1. Even after 30 minutes from the polymerization, the absorption amounts of ethylene and propylene were almost unchanged from those at the beginning of the polymerization. The results are shown in Table 1.

Example 5 The polymerization was carried out in the same manner as in Example 4 except that the polymerization was carried out at 0 ° C. The results are shown in Table 1.

Example 6 Example 4 was repeated except that 1-butene was supplied at 40 l / hr instead of propylene and the polymerization was carried out at 0 ° C.
Polymerization was carried out in the same manner as in. The results are shown in Table 1.

Example 7 In Example 4, ethylene was added at 70 l / hr and 1-butene was added.
Example 4 except that the solution was fed at 30 l / hr and the polymerization was carried out at 0 ° C.
Polymerization was carried out in the same manner as in. The results are shown in Table 1.

Example 8 Example _{4, (π-C 5 H} 5) ₂ instead of _{ZrCl 2 (π-C 5 H} 5) with ₂ ZrClH, rows in the same manner as in polymerization except that the polymerization 1 hour Example 4 Ivy. The results are shown in Table 1.

Example 9 Aluminoxane was synthesized in the same manner as in Example 1 except that mixed aluminum of 90 mmol of trimethylaluminum and 10 mmol of trinormaloctylaluminum was used in place of 100 mmol of trimethylaluminum in Example 1, and the polymerization reaction was also carried out in the Example. I went like 1. The results are shown in Table 1.
Shown in

Example 10 Polymerization was carried out in the same manner as in Example 4 except that 60 l / hr of ethylene and 100 g / l of 1-hexene were fed in Example 4. The results are shown in Table 1.

Example 11 Polymerization After charging 250 ml of purified toluene into a glass autoclave having an internal volume of 500 ml, a mixed gas of ethylene, propylene and 1-butene (60 l / hr, 30 l / hr, 10 l / hr) was passed, Hold at 20 ° C for 10 minutes. Then, aluminoxane synthesized in Example 4 corresponding to 1.25 mg atom in terms of aluminum atom, and 1. in terms of zirconium atom.
(Π−C ₅ H ₅ ) ₂ ZrCl ₂ equivalent to 25 × 10 ^-3 milligram atom
Was charged and the polymerization was started. The polymerization was carried out at 20 ° C. for 30 minutes in a flow system. The subsequent operation was performed in the same manner as in Example 1.
Ethylene content 70% by weight, propylene content 25% by weight,
[Η] 1.63 dl / g, crystallinity 0%, w / n 1.90, B value 1.1
14.1 g of a rubbery copolymer of 8 was obtained. The activity per unit zirconium was 11300 g polymer / milligram atom-Zr.

Example 12 Polymerization 1 Using a continuous polymerization reactor of 1, 500 m of purified toluene was used.
l / hr, the aluminoxane synthesized in Example 4 was 2.5 mg atom / hr in terms of aluminum atom, (π-C ₅ H ₅ ) ₂ Zr
5 × 10 ^-3 mg of Cl ₂ in terms of zirconium atom /
Continuously fed at a rate of hr, ethylene 120l / hr at the same time in the polymerization vessel, propylene 80l / hr and 1,4-hexadiene 1g / hr continuously fed at a rate of 20 ° C, normal temperature, Polymerization was carried out under the condition that the residence time was 1 hour and the polymer concentration was 21 g / l. The produced polymer solution was treated in the same manner as in Example 1. Ethylene content 73% by weight, [η] 1.60 dl / g,
A rubbery polymer having a crystallinity of 1.2%, w / n 1.98, a B value of 1.15 and an iodine value of 9 was obtained. The activity per unit zirconium was 2100 g polymer / milligram atom-Zr.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a preparation process of a catalyst used in the method of the present invention.

Claims (1)

[Claims] 1. In the presence of (A) a compound having a cyclopentadienyl group of a transition metal selected from the group consisting of zirconium, hafnium and vanadium, and (B) an aluminoxane, ethylene and By copolymerizing α-olefin at -50 to 200 ° C, the content of ethylene component is in the range of 20 to 85% by weight, the molecular weight distribution (▲ ▼ / ▲ ▼) is 2.5 or less, and the crystallinity is Is 30% or less and the intrinsic viscosity [η] is 1.21 to 10 dl
Within the range of / g and the following formula (In the formula, P _E represents the content mole fraction of the ethylene component in the copolymer, P _P represents the content mole fraction of the α-olefin component in the copolymer, and P _EP represents the ethylene of the entire dyad chain. · alpha-B value represented by the olefin chain shows the proportion of) is satisfied co ethylene content in the polymer is in the 50 mole% or less _{1.0 + 0.3P E ≦ B ≦ 1} / (1-P E) And the ethylene content of the copolymer is 50
A method for producing a low-crystalline ethylene copolymer, which comprises producing an ethylene copolymer in the range of 1.3-0.3 P _E ≦ B ≦ 1 / P _E at mol% or more.