JPH0242086B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention deals with ethylene, or ethylene and other α
- It relates to a catalyst used in the polymerization of olefins. More specifically, it relates to a novel catalyst that combines a chromium component and a specific zirconium component supported on an inorganic oxide carrier and calcined solid, and a specific organoaluminium compound. This relates to a chromium-based catalyst manufactured by. An ethylene polymerization catalyst obtained by supporting a chromium compound such as chromium oxide on an inorganic oxide support such as silica or silica-alumina and firing it is
Widely known as the so-called Phillips type catalyst,
It is particularly prized for producing wide molecular weight distribution polymers. However, when using this catalyst, the activity of the catalyst and the average molecular weight of the polymer greatly depend on the polymerization temperature, and commercially suitable polymers with molecular weights of tens of thousands to hundreds of thousands can be produced with sufficient catalytic activity. In order to achieve this, it was generally necessary to set the polymerization temperature to 100 to 200°C.
When polymerization is carried out in such a temperature range, the resulting polymer is dissolved in the reaction solvent, so
The viscosity of the reaction system increases significantly, resulting in
It was difficult to increase the concentration of the produced polymer above 20%. Therefore, at polymerization temperatures below 100°C, where the polymerization is so-called slurry polymerization, the catalyst activity is high, especially high enough that the catalyst removal step in the post-polymerization process can be omitted in order to reduce production costs. There is a need for the development of active catalysts. In the past, in order to improve the polymerization activity of this Phillips-type chromium-based catalyst, many catalyst systems combining organoaluminium compounds, organozinc compounds, organomagnesium compounds, etc. have been proposed, but none of them are easy to synthesize and handle industrially. JP-A-52-74688 uses a reaction product of hydropolysiloxane and trialkylaluminum or dialkylaluminium hydride as a catalyst that does not require purification and exhibits high activity even at relatively low temperatures. . However, the polymer produced according to JP-A-52-74688 has a higher swell ratio than commercially available polyethylene, is not compatible with commercially available hollow molding machines, and is disadvantageous in high-speed molding properties. It had some drawbacks. As a result of repeated research to overcome the above-mentioned drawbacks, the present inventors have found that a specific zirconium compound, that is, a water-soluble zirconyl compound that does not contain chlorine atoms, is added to a chromium compound as a chromium-containing solid component, and a solid obtained by supporting and calcining the chromium compound. discovered that by using a specific organoaluminium compound containing both an alkoxy group and a hydroxyloxy group, or an alkoxy group, a catalyst capable of producing a polymer with a low swell ratio with high activity can be obtained, and the present invention Reached. Note that the present invention uses a specific organoaluminum compound containing both an alkoxy group and a hydroxyloxy group, but the chromium-containing solid formation side The swell ratio is even lower than that of the conventional method (in which no water-soluble zirconyl compound is used), which is truly preferable. That is, the present invention provides (a) chromium trioxide or a compound that at least partially forms chromium oxide upon calcination, and a water-soluble zirconyl compound that does not contain a chlorine atom,
A solid component supported on an inorganic oxide carrier and fired, (b) General formula AlR ¹ _p H _q (OR ² ) _x (OSiHR ³ R ⁴ ) _y (where p≧1, 1≧q≧0, x ≧0.25, y≧
0, 1.5≧x+y≧0.5 and p+q+x+y=3
and R ¹ , R ² , R ³ , and R ⁴ are the same or different hydrocarbon groups having 1 to 20 carbon atoms. be. The catalyst of the present invention, which is a combination of a solid component obtained by adding a specific zirconium compound to a chromium compound, supported on a carrier, and calcined, and a specific organoaluminium component, has the characteristics proposed in the past, as will be clear from the Examples and Comparative Examples described below. The swell ratio of the produced polymer is much smaller than that of the catalyst system described in JP-A-52-74688. Furthermore, the swell ratio is also lower than that of the catalyst system described in Japanese Patent Application No. 193667/1983, which was the inventor's earlier invention. This has great industrial value in terms of compatibility with commercially available hollow molding machines and high-speed molding performance. The above-mentioned effects of the present invention, which combines a specific organic aluminum compound with a solid component obtained by adding a specific zirconium compound to a chromium compound, supporting it on a carrier, and firing it, are unexpected and surprising. The present invention will be explained in detail below. First, the solid component (a) will be explained. Examples of the inorganic oxide carrier used in the present invention include silica, alumina, silica-alumina, zirconia,
Although thoria and the like can be used, silica and silica-alumina are preferred, and commercially available silica for highly active catalysts (high surface area, high pore volume) is particularly preferred. Supporting chromium compounds include chromium oxides, or compounds which at least partially form chromium oxide upon calcination, such as chromium halides, oxyhalides, nitrates, acetates, sulfates, oxalates, alcoholates. etc. Water-soluble compounds are preferred for the present invention, and specific examples include chromium trioxide, ammonium dichromate, chromium-rich magnesium, calcium chromate, chromium nitrate, and chromium acetate. Chromium is preferably used. As the zirconium compound, a water-soluble zirconyl compound containing no chlorine atom is used in the present invention. Specific examples include zirconyl nitrate, zirconyl acetate, acidic zirconyl sulfate, zirconyl ammonium acetate, zirconyl phosphate, etc. Zirconyl nitrate ZrO(NO ₃ ) ₂ 2H ₂ O and zirconyl acetate ZrO(CH ₃ COO) ₂ are particularly preferred. used. The chromium compound and zirconium compound are supported on the carrier by preparing an aqueous solution and using known methods such as impregnation and water distillation. The chromium compound and the zirconium compound can be supported by either a two-step method in which separate aqueous solutions are made and one is supported, and then the other is supported, or a one-step method in which an aqueous solution containing both is prepared and supported.
Preferably the latter one-stage method is used. The amount of chromium supported ranges from 0.05 to 5%, preferably from 0.1 to 3%, in weight percent of chromium atoms relative to the support. The amount of supported zirconium is relative to chromium. It is preferably in the range of 0.5 to 10 times by weight, particularly 1 to 5 times by weight. Calcination activation is also carried out in a known manner and is generally carried out in a non-reducing atmosphere, for example in the presence of oxygen, but it can also be carried out in the presence of an inert gas or under reduced pressure. Preferably, air substantially free of moisture is used. Firing temperature is over 300℃,
Preferably, it is carried out at a temperature range of 400°C to 900°C for several minutes to several tens of hours, preferably 30 minutes to 10 hours. During firing, it is recommended to blow in sufficient dry air and activate firing under a fluidized state. Of course, it is also possible to use a known method of controlling activity, molecular weight, etc. by adding titanates, fluorine-containing salts, etc. during supporting or firing. Next, the general formula used for component (b) in the present invention is
The organoaluminum compound represented by AlR ¹ _p H _q (OR ² ) _x (OSiHR ³ R ⁴ ) _y will be explained. In the above formula, R ¹ , R ² , R ³ and R ⁴ represent the same or different hydrocarbon groups having 1 to 20 carbon atoms. Examples include alkyl groups such as methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, decyl, and dodecyl, cycloalkyl groups such as cyclohexyl and methylcyclohexyl, and aryl groups such as phenyl, preferably having 2 carbon atoms.
~10 alkyl groups. Regarding p, q, x, y, p≧1, 1≧q≧0, x≧0.25, y≧0,
1.5≧x+y≧0.5 and p+q+x+y=3. The number p of hydrocarbon groups in Al-R is preferably p≧1.5, particularly preferably p≧1.5.
2.5≧p≧2. The number x of alkoxy groups and the number y of hydroxyloxy groups are important in the present invention, and preferably 1.5≧x+y≧0.75,
In order to obtain a polymer with high activity and a small swell ratio, it is particularly recommended that 1≧x+y≧0.75. An organoaluminum compound containing both an alkoxy group and a hydroxyloxy group may be synthesized, for example, by the following method. Method A A hydrosiloxy group-containing organoaluminum compound obtained by reacting a trialkylaluminum or dialkylaluminum hydride with a poly(or oligo)hydrosiloxane in a desired amount ratio is quantitatively reacted with an alcohol (or phenol) to form an OR. Introduce groups. Method B: OR group-containing organoaluminum compounds such as dialkyl aluminum alkoxides,
Hydrosiloxy groups are introduced by reacting with poly(or oligo)hydrosiloxane in a desired amount ratio. Regarding the first stage of method A, the applicant's patent publication
46-40334 and US Pat. No. 3,661,878, it is described in detail together with the NMR spectrum of the reactant and is well known. That is, the reaction may be carried out with or without a hydrocarbon solvent at a temperature of room temperature to 200° C. for several hours to several tens of hours under an inert atmosphere. The latter part of Method A is preferably carried out by a conventional method in which an alcohol is added dropwise to an organoaluminum compound to react in the presence of a hydrocarbon solvent.
Although there are no particular restrictions on temperature and time, it is preferably carried out by cooling to room temperature or below. Method B is also carried out in the same manner as the first step of method A. Examples of organoaluminum compounds used as raw materials in Method A or Method B include trimethylaluminum, triethylaluminum, trin-
Propyl aluminum, triisobutyl aluminum, trihexyl aluminum, trioctyl aluminum, tridecyl aluminum, tridodecyl aluminum, triphenyl aluminum, diethylaluminium hydride, diisobutyl aluminum hydride, diethyl aluminum ethoxide, diethylaluminium n-
butoxide, diisobutylaluminum ethoxide, etc., and mixtures thereof. Alcohols (or phenols) used in method A include methanol, ethanol,
n-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol,
Examples include hexanol, octanol, phenol, benzyl alcohol, and mixtures thereof. The poly(or oligo)hydrosiloxane used as a raw material in Method A and Method B has the general formula

The one expressed by [formula] is usually used. It will be done. In addition, for example, general formula

Cyclic oligomers of the form can also be used. R
Although methyl, ethyl, phenyl, etc. can be used, methyl is usually used. The poly(or oligo)hydrosiloxane mentioned above can have various viscosities, but those having a viscosity of 10 to 1000 centistokes at 30°C are preferably used. Next, a method of combining the solid component (a) (ie, the chromium- and zirconium-containing solid supported on a carrier and activated by firing) and the organic aluminum component (b) will be described. The solid component (a) and the organoaluminum component (b) are:
They may be added to the polymerization system under polymerization conditions, or may be combined prior to polymerization. Also,
It is also possible to use a method in which the solid component is previously treated with the organoaluminum component and then further combined with the organoaluminium and fed into the polymerization system. The ratio of both components to be combined is Al/Cr 0.01
A range of ~3000, preferably 0.05-100 is recommended. Next, a method for polymerizing olefin using the catalyst of the present invention will be explained. Olefins which can be polymerized using the catalysts of the invention are alpha-olefins, especially ethylene. Furthermore, the catalyst of the present invention can also be used for copolymerization of ethylene with monoolefins such as propylene, butene-1 and hexene-1, or for polymerization in the coexistence of dienes such as butadiene and isoprene. By carrying out copolymerization using the catalyst of the present invention, it is possible to produce a polymer having a density in the range of 0.91 to 0.97 g/cm ³ . As the polymerization method, usual suspension polymerization, solution polymerization, and gas phase polymerization are possible. In the case of suspension polymerization or solution polymerization, the catalyst is a polymerization solvent such as propane,
Aliphatic hydrocarbons such as butane, pentane, hexane, and heptane, aromatic hydrocarbons such as benzene, toluene, and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane are introduced into the reactor under an inert atmosphere. By pressurizing ethylene at 1 to 200 kg/cm ² to the bottom, polymerization can be carried out at a temperature of room temperature to 320°C. In addition, it is also possible to apply a so-called high-pressure polymerization method in which polymerization is carried out using a tubular reactor, an autoclave reactor, an autoclave to a tubular reactor, etc. at a pressure of 200 to 2000 Kg/cm ² and a temperature of 150 to 300°C. It is possible. On the other hand, in gas phase polymerization, ethylene is heated at a pressure of 1 to 50 Kg/cm ² and a temperature of room temperature to 120°C, using a fluidized bed, moving bed, etc. to ensure good contact between ethylene and the catalyst.
Alternatively, polymerization can be carried out by mixing by stirring or the like. The catalyst of the present invention has high performance, 80℃, 10Kg/cm ²
It shows sufficiently high activity even under relatively low temperature and low pressure polymerization conditions. In this case, since the produced polymer exists in the polymerization system in a slurry state, the increase in viscosity of the polymerization system is extremely small. Therefore,
The polymer concentration in the polymerization system can be increased to 30% or more, which has great advantages such as improved production efficiency. Furthermore, due to its high activity, the step of removing catalyst residue from the produced polymer can be omitted. The polymerization may be carried out in a conventional one-stage polymerization using one reaction zone, or using multiple reaction zones.
It may also be carried out by so-called multi-stage polymerization. The polymer polymerized using the catalyst of the present invention has a wide molecular weight distribution even in ordinary one-stage polymerization, and is extremely suitable for blow molding and extrusion molding applications. Multi-stage polymerization in which polymerization is carried out under two or more different reaction conditions makes it possible to produce polymers with a wider molecular weight distribution. In order to adjust the molecular weight of the polymer, it is of course possible to use known techniques such as adjusting the polymerization temperature, adding hydrogen to the polymerization system, or adding an organometallic compound that tends to cause chain transfer. Furthermore, it is also possible to carry out the polymerization by combining methods such as adding a titanate ester to control the density and molecular weight. Examples of the present invention will be shown below, but the present invention is not limited to these Examples in any way. In addition, the catalytic activity in the examples refers to the monomer pressure.
At 10Kg/ ^cm2 , chromium 1g・1 in the solid component
It represents the amount of polymer produced per hour (g). Also, MI stands for melt index,
According to ASTM D-1238, temperature 190℃, load
Measured at 2.16Kg. FR is temperature 190
It is the quotient obtained by dividing the value measured at ℃ and a load of 21.6 kg by MI, and is known to those skilled in the art as an index representing the breadth of molecular weight distribution. SR is temperature 190
It represents the weight (g) of a total length of 10 cm of molten polymer strand flowing out of the melt indexer under high load at 21.6 Kg at a temperature of 21.6 Kg, and is a measure of the relative swell ratio. Example 1 (1) Synthesis of solid component (a) 0.4 g of chromium trioxide CrO ₃ and zirconyl nitrate
Dissolve 1.8 g of ZrO (NO ₃ ) _{2.2H 2} O in 80 ml of distilled water, and add silica (Fuji Davison Co., Ltd.) to this solution.
Grade 952) 20g was immersed and stirred at room temperature for 1 hour. This slurry is heated to distill off the water,
Subsequently, it was dried under reduced pressure at 120°C for 10 hours.
This solid was calcined at 800° C. for 5 hours under dry air circulation to obtain solid component (a). Obtained solid component
(a) contained 1% by weight of chromium and 3% by weight of zirconium and was stored at room temperature under a nitrogen atmosphere. (2) Synthesis of organoaluminum component (b) Triethylaluminum 100mmol, methylhydropolysiloxane (viscosity at 30℃: 30
Weigh out 50 mmol (based on Si) of n-heptane and 150 ml of n-heptane into a glass pressure-resistant container under a nitrogen atmosphere, and react at 100°C for 24 hours with stirring using a magnetic stirrer to form Al(C ₂ H ₅ ) _2.5 (OSi・
H.CH ₃ .C ₂ H ₅ ) _0.5 heptane solution was synthesized.
Next, 100 mmol of this solution (based on Al) was weighed into a 200 ml flask under a nitrogen atmosphere, and a mixed solution of 50 mmol of ethanol and 50 ml of n-heptane was added dropwise from the dropping funnel under ice-cooling and stirring. After the dropwise addition, the mixture was reacted at room temperature for 1 hour. Al(C ₂ H ₅ ) _2.0 (OC ₂ H ₅ ) _0.5 (OSi・
H.CH ₃ .C ₂ H ₅ ) _0.5 heptane solution was synthesized. (3) Polymerization 20 mg of the solid component (a) synthesized in (1) and 0.1 mmol (based on Al) of the organoaluminum component (b) synthesized in (2)
with 0.8 of dehydrated and deoxygenated hexane,
It was placed in a 1.5 autoclave whose interior was vacuum degassed and replaced with nitrogen. The internal temperature of the autoclave is 80
℃, ethylene was added at 10 Kg/cm ² and hydrogen was added to bring the total pressure to 14 Kg/cm ² . Polymerization was carried out for 2 hours while maintaining the total pressure at 14 kg/cm ² by replenishing ethylene to obtain 130 g of polymer.
The catalyst activity was 325000g polymer/gCr·hr, the MI of the polymer was 0.43, the FR was 90, and the SR was 0.80. Comparative Example A Organoaluminum component Al containing only hydroxyloxy groups as organoaluminum component (b)
The same procedure as in Example 1 was carried out except that (C ₂ H ₅ ) _2.5 (OSi·H·CH ₃ ·C ₂ H ₅ ) _0.5 was used. Polymerization results showed polymer yield of 68g, catalyst activity of 170,000,
The MI was 0.37, the FR was 110, and the SR was 1.01, and the SR was significantly higher than that of Example 1. Comparative Example B Organoaluminum component Al containing only hydroxyloxy groups as organoaluminum component (b)
The same procedure as in Example 1 was carried out except that (C ₂ H ₅ ) _2.0 (OSi·H·CH ₃ ·C ₂ H ₅ ) _1.0 was used. Polymerization results showed polymer yield of 72g, catalyst activity of 180,000,
The MI was 0.48, the FR was 92, and the SR was 1.11, which was significantly higher than that of Example 1. Comparative Example C The same procedure as in Example 1 was repeated except that the use of zirconyl nitrate was omitted in the synthesis of solid component (a). (This catalyst is the catalyst described in Japanese Patent Application No. 56-193667, which is an earlier invention of the present applicant.) The polymerization results were as follows: polymer yield: 128 g, catalytic activity: 320,000,
The MI was 0.67, the FR was 80, and the SR was 0.89, which was higher than that of Example 1. Examples 2 to 9 Catalyst synthesis and polymerization were carried out in the same manner as in Example 1 except that some of the synthesis conditions for the solid component (a) and the organoaluminum component (b) in Example 1 were changed. Obtained the results in the table.

[Table] Example 10 100 mmol of diethyl aluminum ethoxide and 50 mmol of methylhydropolysiloxane (Si basis)
was reacted with 150 ml of n-heptane at 120°C for 48 hours to form Al(C ₂ H ₅ ) _1.5 (OC ₂ H ₅ ) _1.0 (OSi・
H.CH ₃ .C ₂ H ₅ ) _0.5 heptane solution was synthesized. Polymerization was carried out in the same manner as in Example 1 except that 0.1 mmol (based on Al) of this organoaluminum component was used as the organoaluminum component (b). Polymerization results showed polymer yield of 110g, catalyst activity of 275,000,
MI0.41, FR77, SR0.80. Example 11 100 mmol of triethylaluminum, 100 mmol of methylhydropolysiloxane (based on Si) and 200 ml of n-heptane were reacted at 100°C for 24 hours to form Al(C ₂ H ₅ ) _2.0 (OSi・H・CH ₃・C ₂ H ₅ ) _1.0 heptane solution was synthesized. Next, 100 mmol of this organic aluminum solution (based on Al) and 50 mmol of diethylaluminum ethoxide were reacted at 80°C for 2 hours to form Al(C ₂ H ₅ ) _2.0 (OC ₂ H ₅ ) _0.33 (OSi・H・
CH ₃・C ₂ H ₅ ) _0.67 heptane solution was synthesized. This organoaluminum as an organoaluminum component
Polymerization was carried out in the same manner as in Example 1 except that 0.1 mmol (based on Al) was used. Polymerization results are polymer yield 120g, catalyst activity 300000, MI 0.40,
It was FR90 and SR0.81. Example 12 Using a mixed gas of ethylene and butene-1 containing 15 mol% of butene-1 instead of ethylene,
Using isobutane as a polymerization solvent instead of hexane, mixed gas partial pressure 10Kg/cm ² and hydrogen partial pressure 1 at 80℃.
Kg/cm ² , the total pressure including the solvent vapor pressure was 23 Kg/cm ² , and polymerization was carried out in the same manner as in Example 1 using the catalyst of Example 1 except for the above. Polymerization results show a polymer yield of 106g.
The catalyst activity was 265,000, MI 0.42, FR 80, SR 0.81, and the polymer density was 0.932.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the steps for preparing a catalyst in the present invention.

Claims (1)

[Scope of Claims] 1 (a) Chromium trioxide or a compound that at least partially forms chromium oxide upon calcination;
A solid component obtained by supporting and firing a water-soluble zirconyl compound that does not contain a chlorine atom on an inorganic oxide carrier, and (b) a general formula AlR ¹ _p H _q (OR ² ) _x (OSiHR ³ R ⁴ ) _y (in the formula , p≧1, 1≧q≧0, x≧0.25, y≧
0, 1.5≧x+y≧0.5 and p+q+x+y=3
and R ¹ , R ² , R ³ , and R ₄ are the same or different hydrocarbon groups having 1 to 20 carbon atoms. 2. The catalyst according to claim 1, wherein the inorganic oxide support (a) is selected from the group consisting of silica, silica-alumina, and alumina. 3. The catalyst according to claim 1, wherein the inorganic oxide support in (a) is silica. 4. The catalyst according to claims 1 to 3, wherein the calcination in (a) is carried out in a non-reducing atmosphere. 5. The catalyst according to claims 1 to 4, wherein the compound that at least partially forms chromium oxide upon calcination in (a) is chromium acetate or chromium nitrate. 6. The catalyst according to claims 1 to 5, wherein the zirconyl compound in (a) is zirconyl acetate or zirconyl nitrate. 7 (b) In the organoaluminum compound, p≧
1.5, the catalyst according to claims 1 to 6. 8 (b) In the organoaluminum compound, 2.5
The catalyst according to any one of claims 1 to 6, wherein ≧p≧2. 9 (b) In the organoaluminum compound, 1.5
The catalyst according to any one of claims 1 to 8, wherein ≧x+y≧0.75. 10 (b) In the organoaluminum compound, 1
The catalyst according to any one of claims 1 to 8, wherein ≧x+y≧0.75.