JPH0816140B2 - Process for producing block copolymer of propylene - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a propylene block copolymer. More specifically, the present invention relates to a method for producing a block copolymer using a catalyst that has been subjected to a specific treatment, under the condition that substantially no inert medium is present.

[Conventional technology]

Polypropylene is a polymer having excellent rigidity, but its impact resistance, especially at low temperatures, is inferior, so impact resistance has been improved by performing block copolymerization with other olefins such as ethylene. (For example, Japanese Patent Publication 43-1123
0, JP-B-44-20621, etc.) However, when block copolymerization is performed, the impact resistance is improved but the rigidity is inevitably lowered. Therefore, in order to obtain a good balance between rigidity and impact resistance, various methods have been proposed, such as a reaction ratio of a portion to be copolymerized with another olefin such as ethylene in the latter stage, or a molecular weight of the portion in an appropriate range. ing. (For example, Japanese Examined Patent Publication No. Sho 47-7141, Japanese Patent Laid-Open No. Sho 55-
No. 43152, JP-A-54-139693, JP-A-56-55416, JP-A-58-83015, etc.) [Problems to be solved by the invention] Although a polymer has been obtained, it is still only possible to obtain a polymer having a certain degree of physical property balance depending on the ratio of the polymerized portion of propylene alone in the first stage and the copolymerized portion of ethylene or another olefin in the second stage and propylene. Further, it is desired to develop a method for producing a block copolymer having an improved physical property balance.

[Means for solving problems]

The present inventors have earnestly studied a method for solving the above problems and completed the present invention. That is, the present invention is titanium trichloride obtained by reducing titanium tetrachloride with aluminum or organoaluminum, or a modified product thereof, or magnesium chloride or a modified product thereof carrying titanium tetrachloride. In a method for producing a block copolymer of propylene using a catalyst composed of a transition metal catalyst component and an organoaluminum compound, the catalyst is 4,4-
Dimethylpentene-1,4,4-dimethylhexene-1,
1 selected from the group consisting of vinylnaphthalene and indene
Bulk polymerization method in which propylene itself is used as a medium after pretreatment with a compound of the kind, or propylene alone is polymerized by a gas phase polymerization method until the proportion in the total polymer becomes 50 to 95% by weight, Then, propylene and ethylene are polymerized by a bulk polymerization method or a gas phase polymerization method in the absence of a substantially inert medium in a ratio of ethylene and propylene of 20/80 to 95/5. It is a method for producing a polymer.

In the present invention, as the catalyst comprising the transition metal catalyst component and the organoaluminum compound, various known catalyst systems which give polypropylene having high stereoregularity can be used.
For example, titanium trichloride obtained by reducing titanium tetrachloride with metallic aluminum, hydrogen or organoaluminum, or those modified with an electron-donating compound and an organoaluminum compound and, if necessary, stereoregularity of an oxygen-containing organic compound, etc. A catalyst system consisting of an improver, or a carrier such as magnesium halide or a product obtained by supporting titanium halide on a product obtained by treating them with an electron-donating compound, and a steric compound such as an organoaluminum compound and optionally an oxygen-containing compound. A catalyst system consisting of a regularity improver is exemplified.
(For example, various examples are described in the following literature. Zi
egler-Natta Catalysts and Polymerization by John
Boar Jr (Academic Press), or Journal of Makromol
ecular Science Reviews in Makromolecular Chemistry
and Physics C24 (3) 355-385 (1984) C25 (1)
57-97 (1985) where stereoregularity improvers or electron donors are usually ethers, esters, orthoesters,
Oxygen-containing compounds such as alkoxy silicon can be preferably used, and as the electron donor, alcohol, aldehyde, water and the like can also be used.

As the organoaluminum compound, trialkylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, and alkylaluminum dihalide can be used.Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, and hexyl group. Is exemplified by chlorine, bromine and iodine.

More specifically, the transition metal catalyst component in the present invention is more specifically one obtained by modification treatment with a titanium trichloride method ether or ester obtained by reducing titanium tetrachloride with aluminum or organoaluminum, or magnesium chloride and an organic compound. Co-milled with titanium tetrachloride, or the reaction product of magnesium chloride and alcohol is dissolved in a hydrocarbon solvent and then treated with a precipitating agent such as titanium tetrachloride to make it insoluble in the hydrocarbon solvent. A supported titanium halide obtained by, for example, modifying with an electron-donating compound such as ester or ether, and then treating with titanium tetrachloride.

What is important in the present invention is that the catalyst is previously subjected to contact treatment with one compound selected from the group consisting of 4,4-dimethylpentene-1,4,4-dimethylhexene-1, vinylnaphthalene and indene. At this time, the use ratio of the organoaluminum compound / transition metal catalyst component may be the same as or less than that in the subsequent polymerization of propylene, and the amount ratio is 0.5 to 1000. Is common. In that case, it is also possible to allow a stereoregularity improver to be present, and the preferable ratio thereof is 0.01 to
300.

The contact treatment temperature and the contact treatment time are not particularly limited, but generally, the temperature is the same as or lower than the temperature during the subsequent polymerization of propylene, and the contact treatment time is several minutes to several hours, preferably Is to treat under the condition that the compound to be subjected to the above-mentioned contact treatment reacts with 0.001 to equivalent or more per transition metal catalyst component. This catalytic treatment is carried out in an inert catalyst for the Ziegler-Natta catalyst such as pentane, hexane, heptane, octane, nonane, decane, benzene, toluene, xylene, ethylbenzene or a mixture thereof, and the unreacted above-mentioned compound is optionally added. It is also possible to remove and wash and further add an organoaluminum compound and use it for the polymerization of propylene.

The amount of the compound used in the above-mentioned contact treatment is preferably 0.01 equivalent times or more per transition metal catalyst component, and if it is less than 0.01 equivalent times, there is almost no effect. Again 20
Even if it is treated under the condition of reacting 0 equivalent times or more, it is not more effective, and when the obtained block copolymer is molded, problems such as poor surface occur.

In the present invention, propylene is first polymerized using the catalyst subjected to the above treatment. At this time, 0 for propylene.
It is also possible to copolymerize other olefins such as ethylene at a weight ratio of 06 or less to improve the surface gloss and the whitening at the time of folding of the obtained block copolymer. Polymerization of propylene should be 50% by weight or more and 95% by weight or less based on the total polymer. If it is less than 50% by weight, the rigidity is insufficient,
If it exceeds 95% by weight, the impact resistance improving effect is insufficient.
The polymerization is carried out by a bulk polymerization method or a vapor polymerization method using propylene itself as a medium, the polymerization temperature is room temperature to 100 ° C., and the polymerization pressure is normal pressure to 50 kg / cm ² gauge. The amount of polymerization per transition metal catalyst component in this part is generally about 1000 to 40,000.

Then, propylene and ethylene are copolymerized by a bulk polymerization method or a gas phase polymerization method in which substantially no inert catalyst is present.
The proportion of the total polymerization method in this part is 5 to 50% by weight. If it is less than 5% by weight, the impact resistance is insufficiently improved, and if it is more than 50% by weight, the rigidity is insufficient. In the copolymerization of propylene and ethylene, it is preferable that the ratio of ethylene and propylene is 20/80 to 95/5 weight ratio, and even if it is less than 20/80 or more than 95/5 weight ratio, the impact resistance is improved. Will be insufficient. Here, 1 part of ethylene is butene-1,
It can be replaced by hexene-1. The reaction in this part is usually carried out under the conditions of normal temperature to 80 ° C. and normal pressure to 50 kg / cm ² gauge.

[Action and effect]

Although the reason is not clear by carrying out the method of the present invention, the crystallization temperature of the obtained block copolymer is increased, and as a result, rigidity, particularly bending rigidity and impact resistance, particularly Izod impact strength is significantly improved, A block copolymer having an excellent balance of physical properties is obtained, which is extremely valuable industrially.

〔Example〕

 The present invention will be further described below with reference to examples.

Example 1 A vibration mill equipped with four grinding pots with an internal volume of 4 l containing 9 kg of steel balls having a diameter of 12 mm is prepared. 300 g magnesium chloride and tetraethoxysilane in a nitrogen atmosphere in each pot
60 ml and 45 ml of α, α, α-trichlorotoluene were added and crushed for 40 hours.

Put 300 g of the above co-ground material into a 5 l flask and add titanium tetrachloride.
1.5 l and 1.5 l of toluene were added, and the mixture was stirred at 100 ° C. for 30 minutes. Then, leave it still to remove the supernatant liquid,
1.5 liters and 1.5 liters of toluene were added, the mixture was stirred at 100 ° C. for 30 minutes, the supernatant was removed, and the solids were further washed with 4 liters of n-heptane 10 times. When 1 part was sampled and the titanium content was analyzed, it was 1.9% by weight.

Toluene 40m in a nitrogen atmosphere in a flask with an internal volume of 200ml
1, 30 mg of the above solid catalyst, 0.128 ml of diethylaluminum chloride, 0.06 ml of methyl p-toluate, 0.03 ml of triethylaluminum and 0.3 g of 4.4-dimethylpentene were added, and the mixture was stirred at 40 ° C. for 30 minutes. Similarly, when another model experiment was performed, the weight of 4,4-dimethylpentene per transition metal catalyst component was 1.1 equivalents. This catalyst slurry was put into an autoclave with an internal volume of 5 liters and propylene 1.5 k
g and 3.3 Nl of hydrogen were added and a polymerization reaction was carried out at 75 ° C for 2 hours. Then, the internal temperature was lowered to 40 ° C, ethylene was added at 5 kg / cm ² gauge, 0.25 ml of triethylaminium was injected, and polymerization was performed for 60 minutes while adding ethylene to a partial pressure of 5 kg / cm ² -gauge. Propylene and ethylene in the reaction were purged, taken out from the autoclave and dried.

The ratio of the copolymerization part of the block copolymer and the reaction ratio of the copolymer were determined by the column fractionation method (Proceedings of the 13th Lecture of the Joint Autumn Meeting of the Chubu Chemistry Association, Chapter 3A20). In addition, the reaction ratio of the copolymerized portion is determined from the ratio X of the copolymerized portion and the ethylene content Y of the block copolymer based on the reaction ratio ethylene / propylene = Y /
(X-Y).

The block copolymer is granulated by adding a phenolic stabilizer 10/10000 weight ratio and calcium stearate 15/10000 weight ratio and measuring the melt flow index to a thickness of 1 m.
An m injection sheet was prepared and the following physical properties were measured.

Melt flow index ASTM D1238 (230 ℃) Tensile strength ASTM D638-64T (20 ℃) Flexural rigidity ASTM D747-63 (20 ℃) Izod (with notch) Impact strength ASTM D256-56 (20 ℃, -10 ℃) DuPont Impact strength JIS K6718 (20 ℃, -10 ℃) The results are shown in Table 1. The polypropylene powder shown in Table 1 has an intrinsic viscosity of 135 ° C. in tetralin solution and boiling
-Heptane extraction residual ratio (abbreviated as II) is the ratio after extraction with boiling n-heptane for 6 hours.

Examples 2-3, Comparative Example 1 4,4-Dimethylhexene-1 (Example 2), α-vinylnaphthalene (Example 3), compounds not used (Comparative Example 1), etc. Was the same as in Example 1. The results are shown in Table 1. The polymerization amount of each compound of Example 2 and Example 3 was 0.8 equivalent and 1.4 equivalent.

Example 4 and Comparative Example 2 A highly active titanium trichloride catalyst (TGY24) manufactured by Marubeni Solway Co. was used as a transition metal catalyst component. In a flask with an internal volume of 200 ml, 40 ml of toluene under a nitrogen atmosphere, titanium trichloride catalyst 10
0 mg, diethyl aluminum chloride 0.5 ml, indene
0.3 ml (Example 4) and without indene (Comparative Example 2) were stirred at 40 ° C. for 30 minutes. Put this catalyst slurry in an autoclave with an internal volume of 5 liters, 1.5 kg of propylene, hydrogen
4.0 Nl was added and a polymerization reaction was carried out at 65 ° C. for 2 hours. Next, the internal temperature was lowered to 40 ° C., 8 kg / cm ² gauge of ethylene was added, and polymerization was carried out for 60 minutes while adding ethylene so that the ethylene partial pressure became constant. Others were the same as in Example 1. The results are shown in Table 1.

〔effect〕

By carrying out the method of the present invention as shown in Examples, a good balance of rigidity and impact resistance, In particular, a block copolymer having excellent flexural rigidity and Izod impact strength can be obtained, which is industrially extremely valuable.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a Ziegler catalyst according to the present invention.

Claims (1)

[Claims] 1. A titanium trichloride obtained by reducing titanium tetrachloride with aluminum or organoaluminum, or a modified product thereof, or a product obtained by supporting titanium tetrachloride on magnesium chloride or a modified product thereof. In a method for producing a block copolymer of propylene using a catalyst composed of a transition metal catalyst component and an organoaluminum compound, the catalyst is 4,4-dimethylpentene-1,4,4-
After pre-contacting with one compound selected from the group consisting of dimethylhexene-1, vinylnaphthalene and indene, propylene alone is used as a medium in a bulk polymerization method or a gas phase polymerization method to produce propylene alone in the whole polymer. The proportion in the part
Polymerize to 50 to 95% by weight, and then use bulk polymerization or gas phase polymerization in which substantially no inert medium is used to produce propylene and ethylene with a ratio of ethylene and propylene of 20/80.
A method for producing a propylene block copolymer, characterized in that the polymerization is carried out in the range of ˜95 / 5.