JPH0377805B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [] Background of the Invention The present invention relates to ultra-high molecular weight polyethylene having a weight average molecular weight of 500,000 to 3,000,000. More specifically, the present invention relates to an ethylene polymerization process characterized by the Ziegler type catalyst used, particularly its organoaluminum component.

Conventionally, a method of increasing the degree of polymerization to increase the molecular weight has been known as a method of improving the performance of polyethylene. It is known that as the molecular weight of polyethylene increases, its impact resistance, abrasion resistance, stress/cracking resistance, chemical resistance, etc. improve. Utilizing this property, ultra-high molecular weight polyethylene is used for gears, packing, etc. It is used in industrial materials such as

In order to produce ultra-high molecular weight polyethylene,
In other words, in order to increase the degree of polymerization of a polymer, it is important to select the type of solid catalyst component, the type of organoaluminium component, and the polymerization conditions.

However, it is desirable that the solid catalyst component is highly active and provides a high molecular weight polymer, but a solid catalyst component that satisfies these two conditions is
hitherto unknown.

Conventional organoaluminum components that yield high molecular weight polyethylene often lack polymerization stability and tend to cause problems such as polymer adhesion and coarse polymer formation.

Regarding polymerization conditions, in order to obtain high molecular weight polyethylene, the polymerization temperature is often lowered;
Various problems such as decreased catalyst activity and decreased productivity are likely to occur.

From this point of view, it is understood that there are still points that need to be improved in order to produce ultra-high molecular weight polyethylene with good productivity and under stable polymerization conditions.

[] Summary of the Invention (Summary) The present invention aims to solve the above-mentioned problems and obtain ultra-high molecular weight polyethylene with a weight average molecular weight of 500,000 to 3,000,000, and uses Ti, Mg, and Cl as essential components. The above objective is achieved by a catalyst system comprising a specific solid catalyst component and a specific organoaluminum component.

Therefore, the method for producing ultra-high molecular weight polyethylene according to the present invention involves bringing ethylene into contact with a catalyst system composed of the following components (A) and (B) at a temperature of 50 to 85°C to reduce the weight average molecular weight. It is characterized by producing 500,000 to 3,000,000 polyethylene.

Component (A) A solid catalyst component containing Ti, Mg and Cl as essential components.

Component (B) Formula R ¹ _3-o AlX _o and Formula R ² _3-n Al(OR ³ ) _n respectively
It consists of a combination of organic aluminum compounds represented by OR ³ and R ¹ + R ² bonded to aluminum.
[Here, R ¹ and R ² are each a hydrocarbon residue or hydrogen which may be the same or different, and R ³ is R ¹ to ^{R 2} is a hydrocarbon residue that is the same as or different from , X is a halogen, and n and m represent On<3 and 0<m3, respectively. ].

(Effects) In producing ultra-high molecular weight polyethylene, the present invention is superior to the prior art described above in the following points.

B Since it is highly active, the so-called decatalyst step can be omitted.

(b) Productivity is good because there is no need to lower the polymerization temperature.

The effects of the above A and B are obtained by combining the ingredient (A) and the ingredient according to the present invention.
This can only be achieved by using a catalyst system consisting of (B). That is, component (A) is necessary to omit the decatalyst step, and component (B) is necessary to improve productivity.

Conventionally, ethylene,
It is known that a highly active polymer can be obtained by polymerizing α-olefins such as propyne. However, in order to produce ultra-high molecular weight polyethylene using these catalysts, it is necessary to lower the polymerization temperature, resulting in poor productivity, so they are usually not used. In the present invention, by using a specific organoaluminum component (component B), it is possible to use an Mg-supported transition metal catalyst component (component A) in the production of ultra-high molecular weight polyethylene.

In component (B), if only one of R ¹ _3-o AlX _o or R ² _3-n Al(OR ³ ) _n is used, no effect will be observed, and the combination of the two components will produce no effect. The effects of the present invention can only be seen in this case.

Furthermore, it is often difficult to granulate ultra-high molecular weight polyethylene, so polyethylene powder is often used as a commercial product. In that case,
Powder form is extremely important. In the present invention, by producing component (A) in a specific manner,
It is also possible to produce ultra-high molecular weight polyethylene in good powder form.

[] Detailed Description of the Invention 1 Component (A) 1) Definition or Type Any conventionally known solid component can be used as long as it contains Ti, Mg and Cl as essential components. For example, the techniques disclosed by the present inventors include Japanese Patent Publication No. 54-23394, Japanese Patent Application Publication No. 51-82385, Japanese Patent Application Publication No. 145388-1988, Japanese Patent Application Publication No. 40293-1973, and Japanese Patent Application Publication No. 54-40293. No. 45696, Japanese Patent Publication No. 1983
−118394, Japanese Patent Application Publication No. 120288, Japanese Patent Application Publication No. 1973-
No. 21435, JP-A-55-145707, JP-A-57-
No. 180612, JP-A-58-5309, JP-A-58-5310
No. 58-183709, etc.

Preferred as component (A) are, for example,
Co-pulverized MgCl ₂ and TiCl ₃ with an electron donor if necessary, or pulverized
MgCl ₂ in contact with a liquid titanium compound such as TiCl ₄ .

2) Production Component (A) is preferably obtained by the following method.

(1) Manufacture of carrier During manufacture, in addition to magnesium halide as an essential component, a dissolving agent for magnesium halide such as titanate or polytitanate, and solid particles such as a polymeric silicon compound are used. A treatment agent for precipitation is appropriately selected. For example, as a specific example, the carrier portion of the catalyst component (A) can be produced from the following components (a) to (c).

(a) Magnesium dihalide Examples include MgF ₂ , MgCl ₂ , MgBr ₂ and the like.

(b) Titanate ester and polytitanate ester As titanate ester, Ti
(OC ₂ H ₅ ) ₄ , Ti(O-nC ₄ H ₉ ) ₄ , Ti(O-
nC ₅ H ₁₁ ) ₄ , Ti(O-nC ₆ H ₁₃ ) ₄ , Ti(O-
nC ₇ H ₁₅ ) ₄ , Ti(O-nC ₈ H ₁₇ ) ₄ , Ti(O-
Examples include nC ₁₀ H ₂₁ ) ₄ and Ti(O-nC ₃ H ₇ ) ₄ , and these can be used alone or in combination.

The polytitanate ester is selected, for example, from compounds represented by the following general formula.

( ^R4 to ^R7 are hydrocarbon groups, preferably _C1 to _C10 , especially _C2 to _C4 .
is the number in the range in which the polytitanate, alone or as a mixed solution with other components, is used in liquid form in contact with the magnesium dihalide, usually up to 20, preferably from 2 to 14, especially 2 ~10, is a number of degrees. )
Specifically, tetra-n-butyl polytitanate (l = 2-10), tetra-n-hexyl polytitanate (l = 2-10), or tetraoctyl polytitanate (l = 2-10).
10) etc.

(c) Polymer silicon compound For example, it is selected from compounds represented by the following general formula.

(R ⁰ is a C ₁ -C ₁₀ , especially C ₁ -C ₆ hydrocarbon group.) Specific examples of polymeric silicon compounds having such structural units include methylhydropolysiloxane, ethylhydropolysiloxane , phenylhydropolysiloxane,
Examples include cyclohexylhydropolysiloxane.

Components from these components (a), (b) and (c)
When producing a carrier for (A), the proportions of components (a), (b), and (c) can be adjusted within an appropriate range depending on the performance of the carrier, but in general It is advantageous for (b)/(a) to be in the range of 2 to 10, preferably 2 to 5, and (c)/(b) to be in the range of 1 to 20, preferably 2 to 5.

This carrier can be prepared, for example, by contact-mixing the components (a) to (c) at a temperature range of -100 to 200°C, preferably from 0 to 100°C, for about 10 minutes and 20 hours. It is manufactured by The contact time is preferably about 1 hour to 5 hours.

The three components (a) to (c) are preferably brought into contact with each other under stirring, and may also be brought into contact by mechanical pulverization using a ball mill, vibration mill, or the like.

(2) Production of catalyst component The catalyst component of the present invention includes at least one of the following components (d) to (f), i.e., (d), (e), (d) + (e), to the catalyst carrier component. , (d) + (he), (e) + (he)
or
It consists of bringing (D) + (E) + (F) into contact.

(i) Component (d) Liquid titanium compound Here, "liquid" refers to titanium compounds that are liquid themselves (including those that are complexed and become liquid), as well as those that are liquid as a solution. It includes things that are.

Typical compounds include the general formula Ti
(OR ⁸ ) _4-q X _q (where R ⁸ is a hydrocarbon residue, preferably one having about 1 to 10 carbon atoms, Examples include compounds that

Specific examples of this compound include TiCl ₄ ,
_TiBr4 , Ti _{( OC2H5} ) _Cl3 , Ti
( _OC2H5 ) _2Cl2 ,Ti _{( OC2H5} ) _{3Cl , Ti} (O-
iC ₃ H ₇ ) Cl ₃ , Ti(O−nC ₄ H ₉ )Cl ₃ , Ti(O
−nC ₄ H ₉ ) ₂ Cl ₂ , Ti(OC ₂ H ₅ )Br ₃ , Ti
(OC ₂ H ₅ ) (OC ₄ H ₉ ) ₂ Cl, Ti(O−
_nC4H9 ) _3Cl , Ti _{( O} - _C6H5 ) _Cl3 , Ti(O-
iC ₄ H ₉ ) ₂ Cl ₂ , etc.

In addition, this liquid titanium compound is TiX′ ₄
It may also be a molecular compound reacted with an electron donor (where X' represents a halogen). A specific example of a phosphor compound is _TiCl4 .
CH ₃ COC ₂ H ₅ , TiCl ₄・CH ₃ CO ₂ C ₂ H ₅ ,
_{TiCl4 ・ C6H5NO2} , _{TiCl4 ・ CH3COCl} ,
TiCl ₄・C ₆ H ₅ COCl, TiCl ₄・
C ₆ H ₅ CO ₂ C ₂ H ₅ , TiCl ₄ ClCO ₂ C ₂ H ₅ ,
Examples include TiCl ₄ .C ₄ H ₄ O.

When using components (d) to (f), one of them must contain a halogen. Therefore, when using only component (d) or when using component (d) together with component (d), component (d) must contain a halogen.

(e) Halogen compounds of silicon Compounds represented by the general formula R′ _4-r SiX _r can be used (where R′ is hydrogen or a hydrocarbon residue, X is a halogen, and n is r
r4).

Specific examples of this compound include SiCl ₄ ,
_HSiCl3 , _{CH3SiCl3 , SiBr4} ,
(C ₂ H ₅ ) ₂ SiCl ₂ , (CH ₃ ) ₃ SiCl, etc.

(f) Polymeric silicon compound The definition of this polymeric silicon compound is the same as that of (c) that should be used when producing the carrier component. The component (f) may be the same as or different from the compound (c) used for producing the carrier.

(ii) Contact of carrier components (d) to (f) The amount of each component (d) to (f) to be used is arbitrary as long as the effect of use is recognized, but it is generally preferred to be within the following range.

The amount of the liquid titanium compound (d) to be used may be in a molar ratio of 1 x 10 ^-2 to 100, preferably in a range of 0.1 to 10, relative to the magnesium dihalide (a) constituting the carrier. It is within.

The amount of silicon halogen compound (e) used is:
Magnesium dihalide constituting the carrier
The molar ratio to (a) may be in the range of 1 x 10 ^-2 to 100, preferably in the range of 0.1 to 10.

The amount of polymer silicon compound (f) to be used is the amount of dihalogenated magnesium (b) constituting the carrier.
to, the molar ratio may be within the range of 1×10 ⁻³ to 10, preferably within the range of 0.05 to 5.0.

The preferred catalyst component (A) in the present invention includes the above-mentioned carrier and components (d) to (f), that is, (d), (e), and (d).
+(E), (N)+(E), (E)+(E) or (N)+(E)+(
f),
It is obtained by contacting with.

Contacting may generally be carried out at a temperature range of -100°C to 200°C, preferably 0°C to 100°C. The contact time is usually about 10 minutes to 20 hours, preferably about 1 hour to 5 hours.

It is preferable that the carrier and components (d) to (f) are brought into contact with each other under stirring. The order of contact can be arbitrary as long as the effect is observed. Any of the components (d), (e), or (and) (f) may be brought into contact with the carrier first. Further, the contact can also be carried out in the presence of a dispersion medium or a solvent. As the dispersion medium at this time, the same one used when producing the carrier can be used.

2 Component (B) Component (B) has the formula R ¹ _3-o AlX _o and the formula R ² _3-n, respectively.
Al( ^OR3 ) Consists of a combination of organoaluminum compounds represented by _n , ^OR3 bonded to aluminum
The organic aluminum component has a ratio of R ¹ +R ² of 0.1 to 1.0. R ¹ to ^{R 3} are each independently a hydrocarbon residue having about 1 to 10 carbon atoms. However, R ¹ and R ² may be hydrogen.

The combination ratio of both organoaluminum compounds is OR ³ /
The ratio of (R ¹ + R ² ) is 0.1 to 1.0, preferably 0.2 to 0.6,
is selected so that

Specific examples of R ¹ _3-o AlX _o include (a) trialkyl aluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, and (b) diethylaluminum monochloride. , diisobutylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, and other alkylaluminum halides, (c)
Examples include alkyl aluminum hydrides such as diethyl aluminum hydride and diisobutyl hydride. These may be used in combination.

Specific examples of R ² _3-n Al(OR ³ ) _n include diethylaluminum methoxide, diethylaluminum ethoxide, diethylaluminium butoxide, diethylaluminium (2-ethyl) hexoxide, monoethylaluminum diethoxide, monoethylaluminum diethoxide, and monoethylaluminum diethoxide. Examples include dibutoxide, aluminum triethoxide, aluminum triisopropoxide, diethylaluminum phenoxide, dimethylaluminum ethoxide, diisobutylaluminum ethoxide, and the like. These may be used in combination.

Specific examples of combinations of the above two components include triethylaluminum and diethylaluminium ethoxide, triisobutylaluminum and diethylaluminum ethoxide, triethylaluminum and diethylaluminium (2-ethyl) hexoxide, triethylaluminum, diethylaluminium chloride and diethyl-aluminum. Examples include ethoxide.

3 Preparation of Catalyst The catalyst system of the present invention is formed by bringing component (A) and component (B) into contact. The amount of the organoaluminum compound used as component (B) is not particularly limited, but the weight ratio to component (A) of the present invention is 1 to 1000, particularly 10 to 1000.
It is preferably within the range of 300.

4 Polymerization The ultra-high molecular weight polyethylene of the present invention is produced by slurry polymerization or gas phase polymerization.

This catalyst system is also effective for continuous polymerization, batch polymerization, or prepolymerization methods. As the polymerization solvent in the case of slurry polymerization, saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, pentane, cyclohexane, benzene, and toluene are used alone or in mixtures. The polymerization temperature is 50°C to 85°C. In addition, other alpha-
Copolymerization with olefins is also possible.

The ultra-high molecular weight polyethylene produced by the present invention has a weight average molecular weight of 500,000 to 3,000,000, particularly 60,000,000 to 3,000,000.
The amount ranges from 10,000 to 2,000,000. The definition and method of measuring weight average molecular weight is well known. The actual measurement method is
For example, see "Polyethylene Resin", pages 46-49 (Plastic Materials Course 4) (Nikkan Kogyo Shimbun).

5 Experimental Examples Example 1 1) Production of catalyst component (component (A)) Into a 1-liter flask purged with nitrogen, put 150 milliliters of thoroughly degassed n-heptane, and then add anhydrous MgCl ₂ (24 mL in a Pall mill).
0.1 mol of Ti (O-
0.03 mol of nC ₄ H ₉ ) ₄ was introduced, the temperature was raised to 70° C., and the mixture was stirred for 1 hour. 0.08 mol of n-butanol was introduced, stirred for 1 hour, and then
0.02 mol of AlCl ₃ was introduced and stirred for 1 hour, and 0.02 mol of TiCl ₄ and 0.15 mol of methylhydrodiene polysiloxane were each introduced and stirred at 70° C. for 2 hours. After the reaction, a portion of the solid component was taken and the Ti content in the solid component was measured, and it was found to be 6.3% by weight, with Mg
= 12.5 weight percent, Cl = 48 weight percent.

2) Polymerization of ethylene Internal volume 1.5 with stirring and temperature control equipment
In a little stainless steel autoclave,
After repeating vacuum-ethylene displacement several times, thoroughly dehydrated and deoxygenated n-heptane was
Subsequently, 50 mg of triethylaluminum, 150 mg of diethylaluminum ethoxide, and 5.0 mg of the catalyst component synthesized above were introduced [OR ³ /
(R ¹ + R ² ) = 0.32]. Furthermore, ethylene was introduced to bring the total pressure to 6 Kg/cm ² . Raise the temperature to 70℃,
Polymerization was carried out for 2 hours. These reaction conditions were kept the same during the polymerization. However, the pressure, which decreases as the polymerization progresses, was kept constant by introducing only ethylene. After polymerization,
After purging the ethylene, the contents were taken out from the autoclave, and the polymer slurry was filtered and dried in a vacuum dryer overnight.

359 grams of polymer (PE) were obtained.
[Catalyst yield (gPE/g solid catalyst component) K=
71800].

When the molecular weight of the polymerized polymer was measured, the weight average molecular weight (hereinafter abbreviated as Mw) was 138.
It was ten thousand. The bulk specific gravity of the polymer is 0.33 (g/
cc).

Example 2 1) Production of catalyst component (component (A)) 50 milliliters of dehydrated and deoxygenated n-heptane was introduced into a flask that had been sufficiently purged with nitrogen, and then 0.1 mol of MgCl ₂ and Ti (O-
0.2 mol of nBu) ₄ was introduced and reacted at 90°C for 2 hours. After the reaction was completed, the temperature was lowered to 40°C, and 12 ml of methylhydrodiene polysiloxane (20 centistokes) was introduced and reacted for 2 hours. The solid component produced was washed with n-heptane. Then 0.05 mol _{of TiCl4} ,
0.05 mol of SiCl ₄ and 50 ml of n-heptane were introduced and reacted at 50° C. for 2 hours. After the reaction was completed, it was washed with n-heptane to obtain a catalyst component (component (A)). When the composition was analyzed, Ti=
7.6 weight percent, Mg=12.7 weight percent, and Cl=44.3 weight percent.

2) Polymerization of ethylene Ethylene polymerization was carried out under exactly the same conditions as in Example 1. 188 grams of polymer was obtained.
K=37,600, Mw=1,030,000, and polymer bulk specific gravity=0.32 (g/cc).

Example 3 Using the catalyst component (component (A)) synthesized in Example 2, ethylene was polymerized under the following conditions. As the organoaluminum component, 75 mg of triethylaluminum and 100 mg of diethylaluminum ethoxide were used [OR ³ / (R ¹
+ ^R2 )=0.22]. After introducing the organoaluminum component and the catalyst component (component (A)) into the autoclave, 3.8 g of butene-1 was introduced and polymerized at 50°C for 10 minutes. Ethylene polymerization was then carried out at 70° C. and 6 kg/cm ² for 2 hours. 202 grams of polymer was obtained. K=40,400, Mw=810,000, and polymer bulk specific gravity=0.37 (g/cc).

Example 4 The catalyst component (component (A)) produced in Example 2 was used, and 50 mg of triethylaluminum and 500 mg of diethylaluminum (2-ethyl) hexoxide were used as the organoaluminum component [OR ³ /(R ¹ + R ² ) = 0.39]
Ethylene polymerization was carried out under exactly the same conditions as in Example 2. 287 grams of polymer was obtained.

K=57400, Mw=1.17 million, polymer bulk specific gravity=
It was 0.36 (g/cc).

Example 5 Using the catalyst component (component (A)) produced in Example 1, 50 mg of triethylaluminum and 150 mg of diethylaluminum ethoxide were used as the organic aluminum component [OR ³ /
(R ¹ +R ² )=0.32], and ethylene was polymerized under exactly the same conditions except that the polymerization temperature was 55°C. 285 grams of polymer was obtained. K=
57000, Mw = 1.63 million, polymer bulk specific gravity = 0.34
(g/cc).

Example 6 1) Production of catalyst component (component (A)) 50 milliliters of purified n-heptane was introduced into a flask purified in the same manner as in Example 1, and then 0.1 mol of MgCl ₂ and Ti (O-nBu) were introduced. ₄ to 0.2
mol was introduced, and the reaction was carried out at 90°C for 2 hours. After the reaction was completed, the temperature was lowered to 40°C, and then 12 ml of methylhydrodiene polysiloxane (20 centistokes) was introduced, and the reaction was allowed to proceed for 2 hours. The solid component produced was washed with n-heptane. Next, 0.04 mol of TiCl ₄ and 12 ml of methylhydrodiene polysiloxane were introduced, and the mixture was reacted at 70° C. for 2 hours. After the reaction was completed, it was washed with n-heptane to obtain component (A). Compositional analysis revealed that Ti = 14.9% by weight, Mg = 5.9% by weight, and Cl = 31.2% by weight.

2) Polymerization of ethylene Using the autoclave used in Example 1, 100 mg of triethylaluminum, 15 mg of diethylaluminum chloride, and 300 mg of diethylaluminum oxide were introduced as organoaluminum components [OR ³ /(R ¹ + R ² ) = 0.31], and 10 milligrams of the solid component (component (A)) synthesized above was introduced. Then, 6.0 grams of propylene was introduced,
Polymerization was carried out at 50°C for 10 minutes. Ethylene polymerization was then carried out at 70° C. and 6 kg/cm ² for 2 hours. 273 grams of polymer were obtained. K=
27300, Mw=610,000, polymer bulk specific gravity=0.46
(g/cc).

Comparative Example 1 Ethylene polymerization was carried out in exactly the same manner except that the catalyst component (component (A)) synthesized in Example 2 was used and 200 milligrams of triethylaluminum was used as the organic aluminum component. 204 grams of polymer was obtained. K=40800, Mw=430,000,
The bulk specific gravity was 0.33 (g/cc).

Comparative Examples 2 to 3 Using the catalyst component (component (A)) synthesized in Example 2, 200 mg of diethylaluminum ethoxide (Comparative Example 2) or 200 mg of ethylaluminum diethoxide (Comparative Example 3) was used as the organoaluminum component. When ethylene was polymerized in exactly the same manner except that each of the following compounds was used, no polymer was obtained in either polymerization.

Comparative Example 4 Ethylene polymerization was carried out in the same manner as in Example 3, except that 200 mg of diethylaluminum chloride was used as the organoaluminum component. As a result, 43 grams of polymer was obtained, Mw = 430,000, polymer bulk specific gravity = 0.29 (g/cc)
It was hot.

Comparative Example 5 Ethylene polymerization was carried out in the same manner as in Example 3, except that 200 mg of ethylaluminum sesquichloride was used as the organoaluminum component. As a result, 2.5 grams of polymer was obtained, with Mw=350,000.

[Brief explanation of drawings]

FIG. 1 is intended to assist in understanding the technical content of the present invention regarding Ziegler catalysts.

Claims (1)

[Claims] 1. Bringing ethylene into contact with a catalyst system composed of the following components (A) and (B) at a temperature of 50°C to 85°C,
A method for producing ultra-high molecular weight polyethylene, which is characterized by producing polyethylene having a weight average molecular weight of 500,000 to 3,000,000. Component (A) A solid catalyst component containing Ti, Mg and Cl as essential components. Component (B) consists of a combination of organoaluminum compounds represented by the formula R ¹ _3-o AlX _o and the formula R ² _3-n Al(OR ³ ) _n , respectively, and is bonded to aluminum.
The ratio of OR ³ and R ¹ + R ² is within the range of 0.1 to 1.0,
Organoaluminum component [Here, R ¹ and R ² are hydrocarbon residues or hydrogen, which may be the same or different, R ³ is a hydrocarbon residue that is the same or different from R ¹ to ^{R 2} , and X is halogen, n and m are 0n<3 and 0<m3, respectively].