SU487089A1 - The method of producing polyethylene - Google Patents

Description

(54) METHOD OF OBTAINING POLYETHYLENE

This invention relates to high density polyethylene using metal ororganic catalysts. A method of producing polyethylene and polymers of ethylene in a medium of a hydrocarbon solvent in the presence of a catalyst consisting of an aryl compound of a metal of Group I or Group III of the periodic system of elements and titanium tetrachloride is known. However, the known method has the following disadvantage: in order to improve the physicomechanical properties of the obtained product by creating an ordered supramolecular structure, it is necessary to preliminary dissolve or melt the polymer, and then crystallize it. This is due to the introduction of additional stages in the process. The aim of the invention is to obtain polyethylene with an ordered supramolecular structure directly in the polymerization process. This goal is achieved by using a solvent that does not dissolve the organometallic component of the catalyst. For this purpose, a solid fixed layer of the organometallic component of the catalyst is formed in the reaction medium and titanium tetrachloride is added to it. The polymer has higher physicomechanical properties than the properties of polyethylene obtained by a known method. This is due to the formation of a standardized supramolecular structure of the fibrillar type directly during the polymerization of ethylene on a heterogeneous catalyst catalyst. Example 1. 250 ml of purified n-heptaia was loaded into glass pea, ktor (0.5 l) under dry argon atmosphere and saturated with ethanol, cooled ipeaKTOp to -20 ° C. Then, 2.55 g of phenyllithium was introduced, and the resulting suspension was added 5.70 g of titanium tetrachloride. The polymerization reaction was carried out at about room temperature for 2 hours. The ethylene feed rate was 15 liters per hour. Termination of the process and decomposition of the catalytic mixture was performed by adding methanol specially released from oxygen to the system. Polyethylene washed and dried. P D and M e R 2. 250 ml of purified n-hexane was loaded into a glass reactor (0.5 l) in a dry argon atmosphere and saturated with ethylene, cooling the reactor to -20 ° C. Then, 3.60 g of aluminum triphenyl was introduced, and 7.98 g of titanium tetrachloride was added to the slurry. The polymerization reaction was carried out at room temperature for 2 hours at an ethylene feed rate of 15 l / h. The termination of the polymerization and the decomposition of the reaction mixture was carried out by adding to the spsemem the methanol, specially released from oxygen.

Example 3 (control). E, su & 1., t. A n-reactor (0.5 l) under argon atmosphere was charged with 250 ml of n-heptane and saturated with ethylene, and the reactor was cooled to -20 ° C. After that, 0.4 g of diethyl alumina ni chloride and 0.8 g of TiCU were introduced. The polymerization reaction was carried out at room temperature at an ethylene feed rate of 15 1 hour. Termination of the reaction P | wired, as in examples 1 and 2.

 Dynamometric testers were carried out on films prepared using polyethylene polyethylene by pressing under pressure. The modes of testing: 60 ° C, a stretching rate of 9.5 mm / min, a film thickness of 180 microns, and a working part length of 3 mm.

The table shows that the polymer samples obtained in examples 1-2, have a pronounced ordered structure of the fibrillar type. At that time, KatK polymers, elongated according to examples 3-4, are large structures whose fibrillar character is practically not expressed. . The ordered structure of the polymers obtained in examples 1-2, the devices in the melt, which largely affects the nature of the morphology of the films of them and, accordingly, mechanical properties of the films.

In the case of aa, in terms of the properties of polyethylates close in molecular weight, molecular weight distribution and branching of the macromolecules of the samples obtained by the proposed and: well known methods, we found differences in the ranges of the temperature of the absorption plate, the heat of fusion and the range of mechanical properties.

In the electron micrograph x, depicted "and FIG. 1-4, are shown above Example 4 (control). 250 L1L of purified toluene was charged to a glass reagent (0.5 l) under argon atmosphere and saturated with ethylene. Then, 2.6 g of phenyl lithium was introduced, and 5.7 g of TiCUPea polymerization was added to the resulting solution at room temperature. The remaining operations were performed, KaiK in example 3.

Xa.r.kteristika samples of polymers obtained in examples 1-4 are shown in the table.

The medical structures of the polyethylene obtained respectively in Examples 1-4.

Subject invention

Claims (2)

1. A method of producing polyethylene by polymerizing ethylene in a hydrocarbon solvent medium in the presence of a catalyst consisting of an aryl compound of metals I ", L. and Group III of the Periodic System of Eleiteites and titanium tetrachloride, characterized in that, in order to obtain polyethylene with ordered in a molecular structure, a solvent is used, not a solution of the aqueous organometallic component of the catalyst. 2. The method according to claim 1, in which case the iB reaction mixture is formed with a fixed layer of organometallic components of the catalyst " titanium tetrachloride is added to it. FIG. 2 Phage. four