Process for Polymerization of Olefins and Polymerization Catalyst

The following examples illustrate the present invention in greater detail.

In the following examples, t-II is a measure of the total isotacticity index of the resulting polymer, and is measured by the following method.

After polymerization, propylene is vaporized to obtain a polypropylene powder, which is then dried. The dried polypropylene powder is subjected to Soxhlet extraction for 6 hours with n-heptane. The amount [B(g)] of that portion of the polymer which is soluble in boiling n-heptane, and the amount A(g)]of that portion of the polymer which is insoluble in boiling n-heptane are measured, and t-II is calculated in accordance with the following equation. ##EQU1##

Anhydrous magnesium chloride (7.14 g; 75 mmoles), 37.5 ml of decane and 35.1 ml (225 mmoles) of 2-ethylhexyl alcohol were reacted at 130.degree. C. for 2 hours to form a uniform solution. Phthalic anhydride (1.67 g; 11.8 mmoles) was added to the solution, and the mixture was stirred at 130.degree. C. for 1 hour to dissolve phthalic anhydride in the uniform solution. The resulting uniform solution was cooled to room temperature, and added dropwise to 200 ml (1.8 moles) of titanium tetrachloride kept at -20.degree. C. over the course of 1 hour. After the addition, the mixed solution was heated to 110.degree. C. over the course of 4 hours. When its temperature reached 110.degree. C., 5.03 ml (18.8 mmoles) of isobutyl phthalate was added, and the mixture was stirred at the above temperature for 2 hours. After the 2-hour reaction, the solid portion was collected by hot filtration. The solid portion was suspended in 275 ml of titanium tetrachloride, and reacted at 110.degree. C. for 2 hours. After the reaction, the solid portion was collected by hot filtration, and washed fully with decane and hexane at 110.degree. C. until no free titanium compound was detected. The solid titanium catalyst component (A) prepared by the above method was stored as a slurry in hexane. Part of the catalyst component (A), however, was dried in order to examine its composition. The resulting solid titanium catalyst component (A) was found to contain 2.5% by weight of titanium, 58% by weight of chlorine, 18% by weight of magnesium and 13.8% by weight of diisobutyl phthalate.

A 400 ml glass reactor purged with nitrogen was charged with 200 ml of purified hexane, and 20 mmoles of triethyl aluminum, 4 mmoles of di-n-propyldimethoxysilane and 2 mmoles, as titanium atoms, of the titanium catalyst component (A) were introduced into the reactor. Propylene was fed into the reactor at a rate of 5.9 Nl/hour for 1 hour, and 2.8 g of propylene was polymerized per gram of the titanium catalyst component (A). After the preliminary polymerization, the liquid portion was removed by filtration, and the solid portion separated was slurried in decane.

A 2-liter autoclave was charged with 500 g of propylene, and at 60.degree. C., 0.6 mmole of triethyl aluminum, 0.06 mmole of di-n-propyldimethoxysilane and 0.006 mmole, calculated as titanium atoms, of the catalyst component (A) subjected to the above preliminary polymerization were introduced into the autoclave. Furthermore, 2 liters of hydrogen was introduced into the autoclave. The temperature was raised to 70.degree. C., and propylene was polymerized at this temperature for 40 minutes. After drying, the total amount of the polymer yielded was 302 g. The polymer had a boiling n-heptane extraction residue of 98.1% and an MFR of 19.8 dg/min. The polymerization activity at this time was 50,300 g of polypropylene/mmole of Ti.

Example 1 was repeated except that in the preliminary polymerization, the amount of triethyl aluminum was changed to 6 mmoles from 20 mmoles, and di-n-propyldimethoxysilane was not added. The results are shown in Table 1.

A 2-liter high-speed stirring device (made by Tokushu Kika Kogyo K. K.) was fully purged with nitrogen, and then charged with 700 ml of purified kerosene, 10 g of commercial MgCl.sub.2, 24.2 g of ethanol and 3 g of Emasol 320 (a tradename for sorbitane distearate produced by Kao-Atlas Co., Ltd.). With stirring, these materials were heated and stirred at 120.degree. C. for 30 minutes at 800 rpm. Under high-speed stirring, the mixture was transferred by a Teflon tube having an inside diameter of 5 mm into a 2-liter glass flask equipped with a stirrer into which 1 liter of purified kerosene cooled at -10.degree. C. had been introduced. The resulting solid was collected by filtration, and fully washed with hexane to give a carrier.

The carrier (7.5 g) was suspended in 150 ml of titanium tetrachloride at room temperature, and then 1.3 ml of diisobutyl phthalate was added. The mixture was then heated to 120.degree. C., and stirred for 2 hours at 120.degree. C. The solid portion was collected by filtration, suspended in 150 ml of titanium tetrachloride, and stirred at 130.degree. C. for 2 hours. The solid reaction product was collected from the reaction mixture by filtration, and washed with a sufficient amount of purified hexane to give a solid titanium catalyst component (A). This component was found to contain 2.2% by weight of titanium, 63% by weight of chlorine, 20% by weight of magnesium and 5.0% by weight of diisobutyl phthalate.

A 400 ml glass reactor purged with nitrogen was charged with 200 ml of purified hexane, and then 20 mmoles of triethyl aluminum, 3 mmoles of di-n-propyldimethoxysilane and 2 mmoles, calculated as titanium atoms, of the titanium catalyst component (A) were introduced into the reactor. Propylene was then fed into the reactor at a rate of 5.9 Nl/hour for 1 hour, and 2.8 g, per gram of the titanium catalyst component (A), of propylene was polymerized. After the preliminary polymerization, the liquid portion was removed by filtration, and the separated solid portion was slurried in decane.

Propylene was polymerized in the same way as in Example 1 except that the catalyst prepared above was used.

Example 1 was repeated except that di-n-butyldimethoxysilane was used instead of the di-n-propyldimethoxysilane used in Example 1. The results are shown in Table 1.

Example 1 was repeated except that di-n-hexyldimethoxysilane was used instead of the di-n-propyldimethoxysilane used in Example 1. The results are shown in Table 1.

The same solid titanium catalyst component (A) as prepared in Example 1 was used, and subjected to the same preliminary polymerization as in Example 1 except that 4 mmoles of cumylmethyldimethoxysilane was used instead of 4 mmole of di-n-propyldimethoxysilane.

A 2-liter autoclave was charged with 500 g of propylene, and at 60.degree. C., 0.6 mmole of triethyl aluminum, 0.06 mmole of cumylmethyldimethoxysilane, and 0.006 mmole, calculated as titanium atoms, of the above catalyst component (A) subjected to the preliminary polymerization were introduced into the autoclave. Furthermore, 2 liters of hydrogen was introduced into the autoclave. The temperature was raised to 70.degree. C., and propylene was polymerized for 40 minutes. After drying, the total amount of the polymer yielded was 278 g. The polymer had a boiling n-heptane extraction residue of 98.2%, and an MFR of 32.6 dg/min. Hence, the polymerization activity at this time was 46,300 g of polypropylene/mmole of Ti.

Example 6 was repeated except that the amount of triethyl aluminum was changed to 6 mmoles from 20 mmoles and cumylmethyldimethoxysilane was not added. The results are shown in Table 2.

The same solid catalyst component (A) as prepared in Example 3 was used, and subjected to the same preliminary polymerization as in Example 3 except that 4 mmoles of cumylmethyldimethoxysilane was used instead of 4 mmoles of di-n-propyldimethoxysilane.

Propylene was polymarized as in Example 6 except that the above solid catalyst component (A) subjected to preliminary polymerization was used. The results are shown in Table 2.

Example 6 was repeated except that 1-phenylethylmethyldimethoxysilane was used instead of dicumyldimethoxysilane. The results are shown in Table 2.

Example 6 was repeated except that 1-phenylethylethyldimethoxysilane was used instead of dicumyldimethoxysilane. The results are shown in Table 2.