JPH0580492B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an ethylene-based random copolymer wax. More specifically, the present invention relates to an ethylene-based random copolymer wax that has a narrow molecular weight distribution and composition molecular weight distribution, less surface stickiness, and a low melting point and low softening point. [Prior Art] Ethylene polymer waxes have heretofore been widely used as various dispersants, aqueous dispersants, modifiers, toners for electrostatic copying, and the like. Also, depending on the field or application, ethylene polymer waxes with low density, low melting point, and low softening point are required, and ethylene/α-olefin random copolymer waxes are used in these fields. . In any of these cases, there is a demand for ethylene polymer waxes that have narrow molecular weight distributions and compositional distributions, and that have low surface stickiness and agglomeration. Recently, in the field of dispersants, aqueous dispersants, modifiers, and toners for electrostatic copying, ethylene/α-olefin random polymers, which have low density, low melting point, and low softening point, and have excellent performance, have been developed. Polymeric waxes are highly desired. Conventionally, methods for producing ethylene polymer wax include polymerizing or copolymerizing ethylene in the presence of a titanium-based catalyst consisting of a titanium compound and an organoaluminum compound or a vanadium-based catalyst consisting of a vanadium compound and an organoaluminum compound. widely known. Ethylene and α-
When producing an ethylene/α-olefin random copolymer wax by copolymerizing olefins, it is obtained using a titanium-based catalyst. Copolymer waxes are generally inferior to random copolymers, have wide molecular weight distributions and compositional distributions, and cannot be said to have achieved sufficient performance in terms of surface stickiness and cohesiveness. Similarly, ethylene/α-olefin random copolymer waxes obtained using vanadium catalysts have improved random copolymerizability and narrower molecular weight and composition distributions than those obtained using titanium catalysts. Although the obtained ethylene has a lower density, lower melting point and lower softening point than those with the same α-olefin content, it is still insufficient for applications where the above performance is strictly required.・α-olefin random copolymer wax is required. On the other hand, a catalyst comprising a zirconium compound and an aluminoxane has recently been proposed as a new Ziegler type olefin polymerization catalyst in the following prior art document. However, none of these prior art documents specifically suggests an ethylene/α-olefin random copolymer wax. JP-A-58-19309 describes the following formula (cyclopentadienyl) ₂ MeRHaI where R is cyclopentadienyl, C ₁ - C ₆
-alkyl, halogen, Me is a transition metal, Hal is a halogen, and a transition metal-containing compound represented by the following formula Al ₂ OR ₄ (Al(R)-O)n, where R is methyl or ethyl and n is 4
consisting of a linear aluminoxane represented by the number ~20 or a cyclic aluminoxane represented by the following formula (Al(R)-O) _o+2 , where the definitions of R and n are the same as above. A method is described in which ethylene and one or more _C3 to _C12 α-olefins are polymerized at temperatures from -50°C to 200°C in the presence of a catalyst. In the same publication,
To adjust the density of the resulting polyethylene, 10
It is stated that the polymerization of ethylene should be carried out in the presence of small amounts of up to % by weight of somewhat long-chain alpha-olefins or mixtures. In Japanese Patent Application Laid-open No. 59-95292, the following formula

[Formula] where n is 2 to 40 and R is C ₁ to C ₆ -alkyl, and a linear aluminoxane represented by the following formula

[Formula] Here, the definitions of n and R are the same as above, and an invention relating to a method for producing a cyclic aluminoxane represented by the following is described. The publication states that when olefin polymerization is carried out by mixing, for example, methylaluminoxane produced by the same production method with a bis(cyclopentadienyl) compound of titanium or zircon, the amount of olefin produced per gram of transition metal and per hour is It is stated that more than 25 million g of polyethylene can be obtained. In Japanese Patent Application Laid-open No. 60-35005, the following formula is

[C] Here, R ¹ is C ₁ to C ₁₀ alkyl, and R ⁰ is R ¹
or combined to represent -O-, is first reacted with a magnesium compound, and then the reaction product is chlorinated and further treated with a Ti, V, Zr or Cr compound to prepare an olefin. A method of making a polymerization catalyst is disclosed. The publication states that the above catalyst is particularly suitable for the copolymerization of a mixture of ethylene and C ₃ -C ₁₂ α-olefin. JP-A-60-35006 discloses that mono-, di-, or tri-cyclopentadienyl of two or more different transition metals or a derivative thereof (a) and alumoxane (aluminoxane) are used as a catalyst system for producing a reactor-blended polymer. Combination (b) is disclosed.
In Example 1 of the same publication, ethylene and propylene were polymerized using bis(pentamethylcyclopentadienyl)zirconium dimethyl and alumoxane as catalysts to produce polyethylene with a number average molecular weight of 15,300, a weight average molecular weight of 36,400, and a propylene component of 3.4%. It is disclosed that the results were obtained. Also,
In Example 2, ethylene and propylene were polymerized using bis(pentamethylcyclopentadienyl)zirconium chloride, bis(methylcyclopentadienyl)zirconium dichloride, and alumoxane as catalysts, and the number average molecular weight was 2200, the weight average molecular weight was 11900, and Number average molecular weight consisting of a toluene soluble portion containing 30 mol% propylene component, a number average molecular weight 3000, a weight average molecular weight 7400, and a toluene insoluble portion containing 4.8 mol% propylene component.
2000, a blend of polyethylene and ethylene-propylene copolymer having a weight average molecular weight of 8300 and a propylene component of 7.1 mol% was obtained. Similarly, in Example 3, the molecular weight distribution (w/n) was 4.57.
and a blend of I, I, DPE and an ethylene-propylene copolymer having a soluble portion of 20.6 mol % of propylene component, a molecular weight distribution of 3.04, and an insoluble portion of 2.9 mol % of propylene component. JP-A-60-35007 discloses that ethylene alone or together with α-olefin having 3 or more carbon atoms, metallocene and the following formula (R-Al-O)n, where R is alkyl having 1 to 5 carbon atoms. and n is an integer from 1 to about 20, or a cyclic alumoxane represented by the following formula R(R-Al-O) _nAlR2 , where the definitions of R and n are the same as above. A process is described in which the polymerization is carried out in the presence of a catalyst system comprising a linear alumoxane. According to the description in the same publication, the polymer obtained by this method has a weight average molecular weight of about 5 million to about 1.4 million, and
It has a molecular weight distribution of 1.5-4.0. Furthermore, JP-A-60-35008 discloses that by using a catalyst system containing at least two kinds of metallocenes and alumoxane, polyethylene or ethylene having a wide molecular weight distribution and C ₃ to _{C 10} α-olefin can be combined. It is described that copolymers are prepared. The publication states that the above copolymer has a molecular weight distribution (
w/n) from 2 to 50. [Problems to be Solved by the Invention] An object of the present invention is to provide a novel ethylene-based random copolymer wax. Another object of the present invention is to have a narrow molecular weight distribution and composition distribution, less surface stickiness, and a low melting point.
An object of the present invention is to provide an ethylene-based random copolymer wax having a low softening point. Still another object of the present invention is to provide an ethylene-based random copolymer wax that has a narrow molecular weight distribution and has less low-molecular-weight portions that tend to tail, and therefore has less stickiness and agglomeration. Still another object of the present invention is to provide an ethylene-based random copolymer wax that has excellent ability to disperse powders such as pigments and can therefore be suitably used as a dispersant such as a pigment dispersant or as a modifier. It's about doing. Further objects and advantages of the present invention will become apparent from the description below. [Means and effects for solving the problems] The objects and advantages of the present invention are, according to the present invention, an ethylene-based random copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms, (a) the content of the ethylene component is in the range 85-99 mol % and the content of the alpha-olefin component is in the range 1-15 mol %; (b) the limit measured in decalin at 135°C. Viscosity [η]
is in the range of 0.02 to 0.5 dl/g, (c) the molecular weight distribution (Mw/Mn) determined by gel permeation chromatography is 2.5 or less, and (d) the crystal size determined by X-ray diffraction method. (e) The following formula () B≡P _OE /2P _O・P _E () [In the formula, P _E indicates the molar fraction of the ethylene component in the copolymer. , P _O indicates the mole fraction of the α-olefin component, and P _OE indicates the mole fraction of the α-olefin ethylene chain in the entire dyad chain.] The B value expressed by the following formula () 1.00≦B ≦2...(), and (f) the ¹³ C-NMR spectrum contains αβ and methylene chains between two adjacent tertiary carbon atoms in the main chain of the copolymer. This is achieved by using an ethylene-based random copolymer wax characterized by the fact that no βγ signal is observed. The above-mentioned ethylene-based random copolymer wax of the present invention is produced by combining ethylene and carbon in the presence of a catalyst consisting of (A) a zirconium hydride compound having a group having conjugated π electrons as a ligand, and (B) aluminoxane. It can be produced by a method of copolymerizing α-olefins having 3 to 10 atoms. The zirconium hydride compound (A) having the above-mentioned group having conjugated π electrons as a ligand can be prepared, for example, by the following formula () R ¹ R ² R ³ ZrH ... () where R ¹ represents a cycloalkadienyl group. ,
R ² and R ³ are a cycloalkadienyl group, an aryl group, an alkyl group, a halogen atom, or a hydrogen atom. The cycloalkadienyl group is, for example, a cyclopentadienyl group, a methylcyclopentadienyl group,
These include ethylcyclopentadienyl group, dimethylcyclopentadienyl group, indenyl group, and tetrahydroindenyl group. Examples of the alkyl group for R ² and R ³ include methyl group, ethyl group, propyl group, isopropyl group,
Examples of the aryl group include a phenyl group, benzyl group, and neophyl group, and examples of the halogen atom include fluorine, chlorine, and bromine. Examples of the zirconium hydride compound include the following compounds. Bis(cyclopentadienyl) zirconium monochloride monohydride, Bis(cyclopentadienyl) zirconium monobromide monohydride, Bis(cyclopentadienyl) methyl zirconium hydride, Bis(cyclopentadienyl) ethyl zirconium hydride, Bis(cyclo pentadienyl)cyclohexylzirconium hydride, bis(cyclopentadienyl)phenylzirconium hydride, bis(cyclopentadienyl)benzylzirconium hydride, bis(cyclopentadienyl)neobenzylzirconium hydride, bis(methylcyclopentadienyl) ) Zirconium monochloride monohydride, bisindenylzirconium monochloride monohydride, The above zirconium hydride compounds can be used as is, but they can be used in a solvent such as toluene such as bis(cyclopentadienyl)zirconium monochloride monohydride. It is preferable to use the poorly soluble compound after contacting it with the organoaluminum compound. By this operation, a zirconium hydride compound that is poorly soluble in a solvent can be made easily soluble in a solvent. Specifically, the organoaluminum compound to be brought into contact with the zirconium hydride compound is trimethylaluminum, triethylaluminum,
Trialkyl aluminum such as tributyl aluminum, trialkenyl aluminum such as triisoprenyl aluminum, dialkyl aluminum alkoxide such as dimethyl aluminum methoxide, diethyl aluminum ethoxide, dibutyl aluminum butoxide, methyl aluminum sesquimethoxide, ethyl aluminum sesquiethoxide, etc. ^{Besides the} _{alkylaluminum sesquialkoxides} of Partially halogenated alkylaluminiums, such as dialkylaluminum halides, alkylaluminum sesquihalides such as methylaluminum sesquichloride and ethylaluminum sesquichloride, and alkylaluminum dihalides such as methylaluminum dichloride and ethylaluminum dichloride, etc. . The reaction between both compounds is preferably carried out in a hydrocarbon medium while blocking light, and the molar ratio of the organic aluminum compound and zirconium compound (Al/Zr)
is 0.5 to 30, preferably 1 to 20, and the concentration of zirconium is 0.001 to 1 per liquid phase.
It is sufficient to keep the amount in mole, preferably about 0.005 to 0.1 mole, and to bring the two into contact at a reaction temperature of about 0 to 120°C. The hydrocarbon medium can be selected from those exemplified as the polymerization solvent described later. Specifically, the aluminoxane B of the catalyst component used in the above method has the general formula () or the general formula ()

[ka]

[Sample preparation]

(a) Transfer the sample to an Erlenmeyer flask together with O-dichlorobenzene solvent to a concentration of 0.1 wt%. (b) Add 0.05 wt% of the anti-aging agent 2,6-di-tert-butyl-p-cresol to the polymer solution in the Erlenmeyer flask containing the sample. (c) Heat the Erlenmeyer flask to 140°C and stir for about 30 minutes to dissolve. (d) Apply the liquid to GPC. [GPC measurement conditions] It was carried out under the following conditions. (a) Equipment Manufactured by Waters (150C-ALC/GPC) (b) Column Manufactured by DuPont (ZORBAX PSM
BiModal-s) (c) Sample amount 200μ (d) Temperature 140℃ (e) Flow rate 1ml/min In addition, the crystallinity of the ethylene random copolymer wax determined by X-ray diffraction is 5 to 85%,
Preferably 10 to 80%, particularly preferably 20 to 80%
It is in the range of 70%. Furthermore, the ethylene-based random copolymer wax of the present invention has the following formula () B≡P _OE /2P _O・P _E ... () [In the formula, P _E is the molar content of the ethylene component in the copolymer. P _O indicates the mole fraction contained in the α-olefin component, and P _OE indicates the mole fraction of the α-olefin ethylene chain in the entire dyad chain (however, the content of each component in the formula () The mole fraction is a value calculated excluding terminal components). ] The B value represented by is in a range that satisfies the following formula () 1.00≦B≦2 ... (). The above B value is an index representing the distribution state of each monomer component in the copolymer chain, and GJRay
(Macromolecules, 10 , 773 (1977)), JC
Randall (Macromolecules, 15 , 353 (1982), J.
Polymer Science, Polymer Physics Ed., 11 ,
275 (1973)), K. Kimura (Polymer, 25 , 441
(1984) et _{al .}
and P _OE is calculated. The larger the B value, the fewer block-like chains, the more uniform the distribution of ethylene and α-olefin, and the narrower the composition distribution of the copolymer. The ethylene random copolymer wax of the present invention preferably has the following B value. 1.3−0.3×P _E ≦B≦1/P _E , more preferably the general formula 1.4−0.4×P _E ≦B≦1/P _E , particularly preferably the general formula 1.5−0.5×P _E ≦B≦1/P _E , The composition distribution B value is approximately in a 10mmφ sample tube.
The ¹³ C-NMR spectrum of a sample obtained by uniformly dissolving 200 mg of mushrooms in 1 ml of hexachlorobutadiene is usually measured at a measurement temperature of 120℃, a measurement frequency of 25.0MHz, and a measurement frequency of 25.0MHz.
Measured under the following measurement conditions: spectrum width 1500Hz, filter width 1500Hz, pulse repetition time 4.2sec, pulse width 7μsec, number of integrations 2000-5000 times, and calculated by determining P _E , P _O , and P _OE from this spectrum. . Furthermore, in the 13-NMR spectrum of the ethylene-based random copolymer wax of the present invention, αβ and βγ signals based on methylene chains between two adjacent tertiary carbon atoms in the copolymer main chain are not measured. . For example, in a copolymer of ethylene and 4-methyl-1-pentene, the following bonds:

When viewed from the tertiary carbon on the left derived from 4-methyl-1-pentene, the three methylene groups in the center are at α, β, and γ positions from the left, while from the tertiary carbon on the right If you look, they are at positions α, β, and γ from the right side. Therefore, in the above binding unit, αγ and ββ
There are methylene groups that give signals for αβ and βγ, but there are no methylene groups that give signals for αβ and βγ. Similarly, the following bond in which 4-methyl-1-pentene is bonded head-to-tail:

In the formula, there is only a methylene group that gives an αα signal, and there are no methylene groups that give αβ and βγ signals. On the other hand, the following combination

[ka] and

〔Example〕

Next, the present invention will be specifically explained using examples. Example 1 Preparation of zirconium catalyst 30 ml of toluene and bis(cyclopentadienyl) were placed in a 100 ml glass flask that was sufficiently purged with nitrogen.
2 mmol of zirconium monochloride monohydride was charged to form a slurry. Trimethylaluminum diluted with toluene (1M solution)
20 mmol was added dropwise at room temperature. After completion of dripping, 60
The temperature was raised to ℃ and allowed to react for 1 hour. Bis(cyclopentadienyl)zirconium monochloride monohydride was dissolved in toluene and the solution turned dark red. Incidentally, the above reaction was carried out in the absence of light. Preparation of methylaluminoxane 13.9 g of magnesium chloride hexahydrate and 125 ml of toluene were placed in a 400 ml glass flask that had been sufficiently purged with argon, and after cooling to 0°C, toluene was added.
250 mmol of trimethylaluminum diluted in 125 ml was added dropwise. After the dropwise addition was completed, the temperature was raised to 70°C and the reaction was continued at that temperature for 96 hours. After the reaction, solid-liquid separation was performed by filtration, and toluene was removed from the separated liquid under reduced pressure to obtain white solid methylaluminoxane 7.3
I got g. The molecular weight determined by freezing point depression in benzene was 1910, and the m value of the aluminoxane was 31. During the polymerization, the aluminoxane was redissolved in toluene. Polymerization Using a 20-unit continuous polymerization reactor, purified toluene was added at 2/hr, methylaluminoxane was added at 10 mg/hr in terms of aluminum atoms, and the zirconium catalyst prepared above was added at 4×10 ^-3 mg in terms of zirconium atoms. Continuously supply ethylene at a rate of 200 atoms/hr in the polymerization vessel.
/hr, 4-methyl-1-pentene 200g/hr,
and hydrogen were continuously supplied at a rate of 20 g/hr, polymerization temperature was 40° C., normal pressure, residence time was 0.5 hours, and polymerization was carried out under conditions such that the polymer concentration was 35 g/hr. The generated polymer solution was continuously extracted from the polymerization vessel, the polymerization was stopped by adding a small amount of methanol, the polymer solution was further transferred into a large amount of methanol, and the precipitated polymer was dried under reduced pressure at 80°C for 12 hours. did. Ethylene content 93.5 mol%, [η]
0.39dl/g, w/n2.17, B value 1.07, crystallinity
41.7%, density 0.905, maximum melting point 98.0℃, softening point
A copolymer wax having a temperature of 105.5°C was obtained. In addition,
The ¹³ C-NMR spectrum of this polymer contains αβ,
No signal based on βγ was observed. The activity per unit of zirconium was 17,500 g-polymer/milligram atom-Zr. Examples 2 to 9 Example 1 except that the polymerization was performed under the conditions shown in Table 1.
I went exactly the same way. In addition, these polymers
No signals based on αβ and βγ were observed in the ¹³ -CMR spectrum. The results are shown in Table 2. Comparative Example 1 Preparation of titanium catalyst 5 g of anhydrous magnesium chloride and 190 ml of purified decane were placed in a 400 ml glass flask, and while stirring,
18.4 ml of ethanol was added dropwise over 1 hour at room temperature. Subsequently, the reaction was continued for 1 hour at room temperature. Thereafter, 17.2 ml of diethylaluminium chloride was added dropwise over 1 hour. At this time, the inside of the system was maintained at 35 to 40°C. After the dropwise addition was completed, the mixture was allowed to react at room temperature for 1 hour. Next, 69.2 ml of titanium tetrachloride was charged and reacted at 80°C for 2 hours. After the reaction, solid-liquid separation was performed by heating, and the solution was washed with decane until titanium was no longer detected. The solid catalyst thus obtained contained 56 milligrams of titanium per gram. Polymerization 720 ml of purified cyclohexane and 280 ml of 4-methyl-1-pentene were charged into an autoclave having an internal volume of 2, and then hydrogen was introduced to make the hydrogen pressure 25 Kg/cm ² -gauge. Thereafter, the temperature was raised to 150°C, and 0.4 milligram atoms of diethylaluminum chloride (in terms of aluminum atoms) and 6×10 ^-3 milligram atoms (in terms of titanium atoms) of the titanium catalyst component were simultaneously injected with ethylene gas to bring the total pressure to 45Kg/cm ² Polymerization started as a gauge. After that, replenish only ethylene gas and keep the total pressure at 45Kg/cm ² gauge at 170℃.
Time polymerization was carried out. After 2 hours, the polymerization was stopped by injecting ethanol. The subsequent operations were performed in the same manner as in Example 1. Polymer yield after drying is 138g
The activity per unit titanium was 23,000 g polymer/milligram atom-Ti. The analysis results of the polymer are shown in Table 2.

【table】

【table】

[Table] * 4-Methyl-1-pentene [Effects of the invention] The ethylene-based random copolymer wax of the present invention has a narrow molecular weight distribution and composition distribution, and is characterized by having a small number of low molecular weight portions that draw a tail in the molecular weight distribution. be. In addition, the ethylene-based random copolymer wax of the present invention has less stickiness and cohesiveness,
Suitable for use as a pigment dispersant, etc.

[Brief explanation of drawings]

FIG. 1 is an example of a differential thermal absorption spectrum of the ethylene random copolymer wax of the present invention. FIG. 2 is a flow chart showing the manufacturing process of the copolymer wax of the present invention.

Claims (1)

[Scope of Claims] 1. An ethylene-based random copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms, wherein (a) the content of the ethylene component is in the range of 85 to 99 mol%; and the content of α-olefin component is in the range of 1 to 15 mol%, (b) the intrinsic viscosity [η] measured in decalin at 135°C
is in the range of 0.02 to 0.5 dl/g, (c) the molecular weight distribution (w/n) determined by gel permeation chromatography is 2.5 or less, and (d) the crystallinity determined by X-ray diffraction method. (e) The following formula () B≡P _OE /2P _O・P _E () In the formula, P _E indicates the molar fraction of the ethylene component in the copolymer, P _O indicates the molar fraction of the α-olefin component, and P _OE is the α-olefin content of the entire dyad chain.
- represents the mole fraction of olefin-ethylene chains] is in a range that satisfies the following formula () 1.00≦B≦2 (), and (f) in the ¹³ C-NMR spectrum, An ethylene-based random copolymer wax characterized in that αβ and βγ signals based on methylene chains between two adjacent tertiary carbon atoms in the main chain of the copolymer are not observed.