JPH0360327B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing in good yield an ethylene/α-olefin copolymer which has excellent low-temperature impact resistance, rigidity, and transparency, and which does not have a cloudy or sticky surface when molded. Ethylene/α with excellent low-temperature impact resistance, rigidity, and transparency suitable as blow grade or sheet grade for food containers or film grade for food packaging.
-Many methods are already known for producing olefin copolymers, for example,
There is a method disclosed in Japanese Patent Publication No. 43-11230 and Japanese Patent Publication No. 44-4992. However, these methods have insufficient low-temperature impact resistance and transparency;
-35788 or Japanese Patent Application No. 56-35198, the physical properties such as impact resistance are good, but there is a problem that the appearance of the molded product is poor. In contrast, the method proposed in Japanese Patent Application No. 57-17583 not only has an excellent balance of physical properties but also provides a good appearance of the molded product, making it an excellent method. There was a problem in drying the obtained product. An object of the present invention is to provide a method for producing an ethylene/.alpha.-olefin copolymer which has excellent low-temperature impact resistance, rigidity, and transparency, and which gives molded articles with excellent appearance. Another object of the present invention is to provide a method for producing an ethylene/α-olefin copolymer having the above-mentioned excellent properties in a high yield, and in which the step of recovering the container is omitted or reduced. The method for producing a random copolymer of ethylene/α-olefin according to the present invention comprises contact-treating a composition containing at least a magnesium halide and an organic compound containing a C-O or C-N bond with liquid titanium chloride, and then It is characterized by copolymerizing ethylene and α-olefin using α-olefin itself as a medium using a supported transition metal catalyst obtained by washing with an aromatic hydrocarbon having 6 to 12 carbon atoms and a catalyst consisting of an organoaluminum compound. That is. In the present invention, the composition containing at least a magnesium halide and an organic compound containing a C-O or C-N bond can be produced by a known method or in accordance with these methods, and is not particularly limited. For example, C-
A method of co-pulverizing magnesium halide with an organic compound containing an O or C-N bond, or a method of co-pulverizing dissolved magnesium chloride (e.g. alcohol, ether, ester as a dissolving agent) with a suitable precipitating agent (e.g. silicon halide, halogenated Titanium,
C-
A method of contacting with an organic compound containing an O or C-N bond, or a method of treating an organomagnesium compound with a suitable halogenating agent to form magnesium chloride, and then contacting it with an organic compound containing a C-O or C-N bond. Methods such as Examples of compounds containing C-O or C-N bonds include ethers, esters, orthoesters, phosphoric acid esters, amides, and amines. In producing the above composition, SiO ₂ ,
Inert compounds such as Al ₂ O ₃ can coexist. The composition thus obtained is then contact treated with liquid titanium chloride. As titanium chloride, for example, titanium tetrachloride or titanium trichloride solubilized with an electron donor is used. Contact treatment is usually carried out at room temperature to 140°C, preferably 50 to 140°C while stirring.
Performed at 100℃. During the treatment with titanium chloride, it is also possible to coexist with an aromatic hydrocarbon, which will be described later. The solids treated above are then washed with aromatic hydrocarbons. The cleaning temperature may be around room temperature, and there is no need to perform the cleaning at particularly high or low temperatures. Washing can be repeated so that the ratio of Ti in the supported transition metal catalyst to free Ti is approximately 1:1/100. Aromatic hydrocarbons that can be used are those having 6 to 12 carbon atoms, and specific examples include benzene, toluene, xylene, ethylbenzene, and cumene. Examples of organoaluminum compounds include dialkylaluminum chloride such as diethylaluminum chloride, dipropylaluminum chloride, dibutylaluminum chloride, triethylaluminum, tripropylaluminum,
Trialkylaluminiums such as tributylamminium and trihexylaluminum are used alone or as a mixture. The polymerization method of the present invention is carried out in the presence of a catalyst in combination of a supported transition metal catalyst and an organoaluminum, and more preferably esters, ethers, orthoesters, amines, amides, phosphoric esters,
A stereoregularity enhancer such as a phosphite is used as the third component. Copolymerization of ethylene and α-olefin is performed using the above catalyst. The polymerization reaction is carried out under normal conditions, and there are no particular restrictions, but preferably at room temperature to 100°C,
It is carried out under the conditions of normal pressure to 50Kg/cm ² -gauge. Polymerization methods that are more effective in the present invention are bulk polymerization methods or gas phase polymerization methods using α-olefin itself as a medium, and among these, bulk polymerization methods are preferred. Here α−
Olefin refers to propylene, butene-1, hexene-1, a mixture of 80 mol% or more propylene and 20 mol% or less butene-1 or hexene-1, or 100% propylene. The ethylene content of the copolymers obtained by the method of the invention ranges from 0.5 to 10% by weight. By using the method of the present invention, it is possible to efficiently produce an ethylene/α-olefin copolymer having excellent properties, which is of industrial value. The present invention will be specifically explained below with reference to Examples. In the examples and comparative examples, the physical properties were determined by using a phenolic stabilizer at a weight ratio of 20/10000 to the copolymer.
Calcium stearate at a weight ratio of 10/10000,
A lubricant was added at a weight ratio of 20/10000, and 250
After granulation at 240°C, a T-die film with a thickness of 30 μm and a width of 25 cm was prepared and evaluated. Measurements of each physical property are as follows. Intrinsic viscosity: Measured with tetralin solution at 135°C Haze (%): ASTM-1003-53 Blocking (%): After stacking two films and placing a 2 kg weight on them and keeping them at 50°C for 24 hours, as a percentage of the adhesion area calculation. Young's modulus (Kg/mm): Measured using an Instron using a 20mm x 220mm film. Tensile strength (Kg/ ^cm2 ): ASTM D882-64T Impact (Kg, cm/mm): 10mm film at 5℃
Calculated based on the impact energy when a 10 mm object is damaged by impact with a spherical weight. Embossment: Determined visually after holding the film at 50°C for 24 hours. Example 1 (A) Production of supported transition metal catalyst: 20 g of magnesium chloride and 1 ml of ethyl orthoacetate in a nitrogen atmosphere in a grinding pot with an internal volume of 600 ml containing 80 steel balls with a diameter of 12 mm, equipped with a vibration mill. , add 4 ml of 1,2-dichloroethane and add 40
Time crushed. 10 g of the above pulverized material and 50 ml of titanium tetrachloride were added to a 200 ml round-bottomed flask, and the mixture was stirred at 80° C. for 2 hours, and then the supernatant liquid was removed by decantation. Next, 100 ml of toluene was added, stirred at room temperature for 15 minutes, and the washing operation of removing the supernatant liquid by decantation was repeated 7 times, followed by an additional 100 ml of toluene to form a carrier transition metal catalyst slurry. . A part of this slurry was sampled, toluene was evaporated and analyzed, and the Ti content in the carrier transition metal catalyst was found to be
It was 1.75wt%. Also, the slurry concentration is 67g/
-It was toluene. (B) Polymerization reaction: Charge 25 kg of propylene into a jacketed 100 autoclave that has been thoroughly dried, purged with nitrogen, and then purged with propylene. On the other hand, 200 ml of n-heptane, 2.6 ml of diethylaluminium chloride, 1.4 ml of methyl p-toluate, and 1 g of the above catalyst (including 15 ml of toluene) were placed in flask 1, and after stirring at room temperature for 0.1 hour, 0.5 ml of triethyl aluminum was added. The above 100 parts were press-fitted in an autoclave. Charge hydrogen and ethylene in predetermined amounts, then pass hot water through the jacket to bring the internal temperature to 70°C, and while charging hydrogen and ethylene, keep the gas phase hydrogen concentration at 6% and the ethylene gas phase concentration at 2.4%. Polymerization continued. on the other hand
Polymerization was continued for 2 hours while continuously pressurizing a solution of 3.5 ml of triethylaluminum in 56.5 ml of n-heptane into the autoclave at a rate of 0.5 ml/min and propylene at a rate of 125 g/min. After 2 hours, add 10ml of diethylene glycol monoisopropyl ether and stir at 70℃ for 30 minutes.
cm, the length is 10m and the inner diameter of the thick part at the top is 30cm,
The slurry was placed at the top of a countercurrent cleaning tower with a length of 30 m.
Kg/h, a cleaning solution with a composition of 90% propylene, 5% propane, 1% ethylene, and 4% n-heptane was introduced from the bottom at a rate of 40Kg/h, and the cleaning solution was introduced from the top at a rate of 44Kg/h, and from the bottom. The slurry was taken out at a rate of 26 kg/h, and the taken out slurry was discharged into a cyclone maintained at atmospheric pressure through a double pipe with an inner diameter of 3/4 inch and a length of 60 m. The double tube was heated through steam at 1 kg/cm ² G. The powder taken out from the cyclone contained 0.1% volatile matter. When the obtained powder was further dried at 50°C and 50 mmHg for 10 minutes, 18.1 kg of polymer was obtained, and 0.7 kg of polymer was recovered from the washing liquid from the upper part of the unidirectional flow washing tower. The ratio of the product to the total polymer (hereinafter referred to as product yield) was 96.3 wt%. The obtained powder was granulated and formed into a film under the conditions described above, and its physical properties were measured. Examples 2 to 5 Comparative Examples 1 to 2 The solvent for cleaning the supported transition metal catalyst was xylene (Example 2), ethylbenzene (Example 3), cumene (Example 4), benzene (Example 5), n- The same method as in Example 1 was carried out, except that hexane (Comparative Example 1) and n-heptane (Comparative Example 2) were used. The results are shown in the table.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a flow chart of a catalyst used in the copolymerization method of the present invention.

Claims (1)

[Claims] 1 Magnesium halide and C-O or C-
α-
A method for copolymerizing olefin, which comprises copolymerizing ethylene and α-olefin using olefin itself as a medium.