JPS58136607A - Production of ethylene/propylene random copolymer - Google Patents

Abstract

PURPOSE:To obtain the titled copolymer capable of providing a molding excellent in low-temperature impact resistance, rigidity, transparency, etc., by treating a random copolymer prepared by a specified bulk polymerization method with a saturated hydrocarbon-containing liquid propylene and further washing the copolymer with propylene. CONSTITUTION:A process for producing an ethylene/propylene random copolymer having an ethylene content of 0.5-10wt% is carried out in such a manner that (A) the random copolymer is produced at 50-80 deg.C by a bulk polymerization method using propylene itself as a medium and a catalyst comprising a solid catalyst containing an organic compound containing at least Mg, Ti, Cl and C-O or C-N bond, an organometallic compound and a stereoregularity improver, (B) the copolymer A is treated at 30-70 deg.C with a liquid propylene containing at least 5wt% 5-15C saturated hydrocarbon compound and (C) the resulting slurry is introduced into a counter-current scrubbing tower from its top, a propylene- based medium containing below 20wt% 5-15C saturated hydrocarbon compound is introduced from the bottom to wash the slurry, and the washed copolymer is discharged from the bottom.

Description

Detailed Description of the Invention The present invention provides an ethylene/propylene copolymer with excellent low-temperature impact resistance, rigidity, and transparency, and which does not have a cloudy or sticky surface when molded. Regarding the method.

Many methods have already been proposed for producing ethylene/propylene copolymers with excellent low-temperature impact resistance, rigidity, and transparency suitable for blow grade for food containers, sheet grade, or food packaging. For example, Special Publication No. 43-11230. There is a method disclosed in Japanese Patent Publication No. 44-4992.

However, these methods have insufficient low-temperature impact resistance and transparency. On the other hand, JP-A-53-35788
According to the method proposed in the first stage, propylene is polymerized in the range of 5 to 20% by weight of the total polymerization amount, and in the subsequent second stage, propylene with an ethylene content of 1 to 20% by weight is polymerized.
By performing copolymerization with an ethylene mixture, an ethylene/propylene copolymer with an excellent balance of various physical properties such as low-temperature impact resistance, rigidity, and transparency can be obtained at a high product yield.

As a further improved method, the present inventors previously filed a patent application in 1973.
6-35198, but when the polymer obtained by this improved method was molded and used, although the balance of physical properties was excellent, there were problems such as poor appearance.

As a result of various studies, the present inventors discovered a method of producing an ethylene-propylene copolymer with an excellent balance of physical properties and an excellent appearance of molded products by performing a specific method, and completed the present invention. did.

The object of the present invention is to provide an ethylene-based material that has excellent low-temperature impact resistance, rigidity, and transparency, and also has an excellent appearance when molded.
This invention relates to a method for providing propylene copolymers.

Another object of the present invention is to provide a method for producing the above-mentioned excellent ethylene-propylene copolymer in good yield.

The present invention comprises a) a) a solid catalyst containing at least Mf, Ti, CL and an organic compound containing a C-0 or C-N bond; a) an organometallic compound; and...) a stereoregularity improver. Producing a random copolymer at a temperature of 50 to 80 °C by bulk polymerization using a catalyst in propylene itself as a medium, b) followed by saturated carbonization of at least 5% by weight of carbon atoms of 5 to 15 at 30 to 70 °C. The copolymer obtained by the above polymerization is treated in liquid propylene containing a hydrogen compound, and C) The slurry is then introduced into the upper part of a countercurrent washing tower, and a saturated hydrocarbon compound having 5 to 15 carbon atoms is introduced from the lower part. 20%
The diethylene content is reduced to 0 by introducing a medium consisting mainly of propylene and removing the washed copolymer from below.
．． The present invention relates to a method for producing a 5-10% by weight ethylene/propylene random copolymer.

The catalyst used in the present invention includes a) at least Ml, Ti
, a solid catalyst containing an element of C1 and an organic compound containing a C-0 or C-N bond, an organometallic compound, No. 9
It is a catalyst system consisting of a stereoregularity improver, and there are no particular limitations on the combination of (a), (b), and (9) above, but (i) the yield of the solid catalyst is 4000 t/f-solid catalyst or more. Moreover, the proportion of the boiling n-hebutane insoluble portion of the special polypropylene polymerized with propylene alone (hereinafter referred to as I
(abbreviated as I) is preferably 85% or more, particularly 90% or more. Specifically, a) the solid catalyst is prepared by a known method, for example, after co-pulverizing MfCl and an organic compound containing an organic compound containing a C-0 or C-N bond, a titanium halide such as TiCAa is prepared. How to process with,
Alternatively, a method of co-pulverizing the above three components, dissolved MfCl
2 is precipitated or prior to treatment with an organic compound containing a C-- or C-N bond, and then treated with a titanium halide such as TiCt, or the organic M7 compound is decomposed and halogenated. There are methods of treating magnesium in a similar manner.

(1) Examples of the organometallic compound include organoaluminium, organomagnesium, organolithium, etc., and organoaluminium is preferable. Various known compounds can be used as the stereoregularity improver, and preferred examples include esters, ethers, orthoesters, amines, amides, and the like.

One element of the present invention is the copolymerization of ethylene/propylene at 50 to 80°C using a bulk polymerization method using propylene itself as a medium.
However, if it is carried out in a hydrocarbon medium with a relatively high boiling point, a large amount of the copolymer will dissolve in the medium.
This is undesirable because not only the yield of the product decreases, but also the bulk specific gravity of the polymer decreases and the properties of the slurry deteriorate, resulting in a decrease in productivity.

The polymerization temperature is preferably 50 to 80°C, especially 55°C.
More preferably, the temperature is 75°C. When the polymerization temperature is below 50°C, molding using a copolymer will not only result in poor transparency, but also cause problems such as the surface of the molded product being smudged or flat. be. On the other hand, J30℃
If it is more than that, the bulk specific gravity of the powder decreases and productivity decreases, which is not preferable.

During polymerization, a saturated hydrocarbon having 5 to 15 carbon atoms may be present within a range that does not substantially reduce the polymerization activity.

A further element of the present invention is the treatment at 30 to 70°C in liquid propylene containing at least 5% by weight of saturated hydrocarbons having 5 to 15 carbon atoms, the amount ratio of saturated hydrocarbons being 5 to 70°C. It is preferably 60% by weight, especially 10 to 30% by weight; if it is less than 5% by weight, the surface of the molded product becomes cloudy or sticky when molded, which is undesirable. % or more, a large amount of copolymer is dissolved in the medium, resulting in a decrease in product yield. The preferred temperature range is 50 to 60°C, but if the temperature is higher than 0°C, the surface of the molded product may become cloudy or cloudy.
It feels sticky. In order to carry out the process at a temperature below 30°C, not only is there a large difference in the polymerization temperature, but it is also difficult to operate.
If a compound that solubilizes the catalyst residue, such as alcohols or glycol ethers, is added in order to remove the catalyst residue during this operation, the removal efficiency of the catalyst residue will decrease, so the temperature is preferably 50°C or higher. It will be held in

Another element of the present invention is that the slurry from which components that have an adverse effect on the product have been extracted in the above operation is introduced into a countercurrent cleaning tower, and a slurry containing only 20% by weight or less of saturated hydrocarbon compounds having 5 to 15 carbon atoms is used. The copolymer is obtained by washing and extraction with a medium consisting of propylene.

The countercurrent cleaning tower has a slurry introduction and cleaning liquid outlet at the top,
It is sufficient to use an ordinary countercurrent cleaning tower with a cleaning liquid inlet and a cleaned slurry I7 outlet at the bottom, and there is no particular limitation on its shape, and the cleaning liquid may be mainly composed of propylene. may contain small amounts of ethylene, ethane, propane, etc., but the content of saturated hydrocarbon compounds having 5 to 15' carbon atoms must be 20% by weight or less,
If it exceeds 20% by weight, the washed and extracted slurry taken out from the bottom will contain a large amount of saturated hydrocarbons with a relatively high boiling point9. Since the polymer dissolves into the medium, there arise problems such as agglomeration of the resulting powder and the need for special drying equipment because large amounts of high-boiling hydrocarbons remain in the powder.

By using the method of the present invention, an ethylene/propylene copolymer having excellent properties can be efficiently produced and 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 20/1 of the phenolic stabilizer to the copolymer.
0000 weight ratio, calcium stearate 10/100
00 weight ratio, lubricant 20/10000 weight ratio added 250
After granulation at 240°C, a T-die film with a thickness of 30 μm and a width of 25 cm was evaluated.

Each measurement was performed using melt flow index f/10m1n at 230°C with a load of 2.16kF ASTM D-1238-627 Haze (%) ASTM-1003-
53 Blocking (%) Layering two films 2
Young's modulus calculated as the percentage of the adhesion area after 24 hours at 50°C by placing a weight of 1 on the surface (Tensile strength kf/cm" measured using an Itinstron using a 920 mm 8220 mm film) ASTM D882-
Impact (kf-cm/imm) 5℃ according to 64T
When a film of 10 mm x 1 Q mm O is broken by impact with a spherical weight, the impact red energy is embossed. Judgment is made visually after holding the film at 50°C for 24 hours. Example I A) Production of solid catalyst Diameter: 12 mm A vibratory mill equipped with four crushing pots each having an internal volume of 4 tons each containing 9 kF steel balls is prepared. 300 f of magnesium chloride, 40 ml of ethyl orthoacetate/l, and 60 mA of 1,2-dichloroethane were added to each pot under a nitrogen atmosphere and pulverized for 40 hours. 3k of the above pulverized material was placed in a 50t autoclave that was thoroughly dried and kept in a nitrogen atmosphere.
F. Add titanium tetrachloride 201, stir at 80°C for 120 minutes, let stand and remove supernatant, add n-hebutane 35, stir at 80°C for 15 minutes, let stand, and remove supernatant. After the washing operation was repeated 7 times, 201 ml of n-hebutane was further added to prepare a solid catalyst slurry.

When a portion of the solid catalyst slurry was sampled, n-heptane was evaporated, and analyzed, it was found that the solid catalyst contained 1.62% by weight of Ti.

B) Polymerization reaction 25 kg of propylene was placed in a jacketed 100 t autoclave (autoclave A) that was thoroughly dried, purged with nitrogen, and then replaced with propylene. Charge. On the other hand 1
500 mt of n-hebutane, 4.8 ml of diethylaluminum chloride, 2.8 ml of p-)methyl ruylate, and the above solid catalyst 1f were placed in a flask of No. t, stirred for 1 minute at room temperature, and then 1 ml of triethylaluminum was added.
It was press-fitted into a 00t autoclave.

A predetermined amount of hydrogen and ethylene were charged, and then hot water was passed through the jacket so that the internal temperature was maintained at 70°C, the gas phase concentration of hydrogen was 3.8%, and the gas phase concentration of ethylene was 2.5%. Polymerization continued. On the other hand, 3 mt of triethylaluminum dissolved in 57 mt of n-hebutane was continuously pressurized into the autoclave at 0.5 mt/min, and polymerization was continued for 2 hours. After 2 hours, 2.6
Transfer the above slurry to a 100 t autoclave (autoclave B) containing 1 part of n-hebutane and 10 mt of diethylene glycol monoinflovir ether,
Stir for 30 minutes at 55°C, then prepare the slurry with an inner diameter of 10 cm at the narrow part and 30 cm at the upper thick part.
, the length of the thin part is 10 m1, and the length of the thick part at the top is 2 m
30 kg/h of slurry was poured into the upper part of the countercurrent washing tower of
%, n-hebutane 4% cleaning solution at 40 kW/h
The slurry that was washed from the top and the bottom was taken out at a rate of 1/h. It was maintained at atmospheric pressure through heavy pipes. The double tube discharged into the Sunchron was heated by passing 1 kf-G steam.

The powder thus taken out from the cyclone via the hopper contained 0.5% volatile matter.

The obtained powder was further heated at 50°C and 50mmHf for 1
When dried for 0 hours, the polymer was 11.2 kS', and on the other hand, 0.6 kf of polymer was recovered from the washing liquid from the upper part of the countercurrent washing tower. The ratio of the product to the total polymer was as follows: The product yield was 95 wt%. The obtained powder was granulated and film-formed under the conditions described above, and its physical properties were measured.

Example 2 A copolymer was produced in the same manner as in Example 1, except that the polymerization temperature was 55° C., the gas phase hydrogen concentration was 2.7%, and the ethylene concentration was 2.3%. The results are shown in the table.

- Comparative Example 1 A copolymer was obtained in the same manner as in Example 2 except that n-hebutane was not placed in autoclave B.

The results are shown in the table.

Comparative Example 2 The same procedure as in Example 2 was carried out except that the composition of the cleaning liquid charged from the bottom of the countercurrent cleaning tower was 50% propylene, 47% n-hebutane, and 3% furopane. The experiment was discontinued due to blockage.

Example 3 A copolymer was obtained in the same manner as in Example 1, except that the ethylene concentration in the gas phase during polymerization was changed to 3.1%. The results are shown in the table.

Comparative Examples 3 and 4 Copolymers were obtained in the same manner as in Example 1, except that the temperature in the autoclave 03) was 20°C (Comparative Example 3) and 80°C (Comparative Example 4). The results are shown in the table.

Example 4 A copolymer was obtained in the same manner as in Example 1, except that the polymerization was carried out without charging ethylene for 6 minutes from the start of polymerization (completion of temperature rise). The results are shown in the table.

surface

[Brief explanation of drawings]

The drawing is a concept β of the apparatus used to carry out the present invention, A is autoclave A, B is autoclave B, C is a countercurrent washing tower; D is double pipe, E is for cyclone, F is for hopper, a is for removing the cleaning solution, b is the introduction of cleaning liquid, C is the medium vapor; d indicates powder removal. patent applicant Mitsui Toatsu Chemical Co., Ltd. 1 1'7- soil

Claims (1)

[Scope of Claims] 1) A method for producing an ethylene/propylene random copolymer having an ethylene content of 0.5 to 10% by weight, comprising: a) b) at least the elements Ml, Ti, and CL, and C;
Using a solid catalyst containing an organic compound containing an -O or C-N bond, an organometallic compound, and a stereoregularity improver, a bulk polymerization method using propylene itself as a medium is used. producing a random copolymer at a temperature of 80°C; b) then at 30-70°C in liquid propylene containing at least 5% by weight of a saturated hydrocarbon compound having 5 to 15 carbon atoms; C) The above slurry is then introduced into the upper part of the countercurrent washing tower, and the lower part contains only 20% by weight or less of a saturated hydrocarbon compound having 5 to 15 carbon atoms. The slurry is washed by introducing a medium consisting mainly of propylene, and the washed copolymer is taken out from below. A method for producing an ethylene/propylene random copolymer, characterized by: