JPH0549691B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention has excellent low-temperature impact resistance, rigidity, and transparency, and when the film is molded, the surface does not become cloudy.
This invention relates to an ethylene/propylene random copolymer that does not become sticky. [Prior Art] Many compositions and copolymerization methods have already been proposed for ethylene/propylene copolymers that have excellent low-temperature impact resistance, rigidity, and transparency and are suitable for various uses, particularly for food packaging. [Problem to be solved by the invention] When a film is formed from an ethylene/propylene random copolymer with a high ethylene content, which requires a high ethylene content in order to improve low-temperature impact resistance, the surface becomes cloudy or sticky. I had a problem. The inventors of the present invention have conducted various studies on methods to solve the above problems, and have found that a specific copolymer has excellent low-temperature impact resistance, rigidity, and transparency. The present invention was completed by discovering that there is no problem of stickiness. An object of the present invention is to obtain an ethylene-propylene copolymer that has excellent low-temperature impact resistance, rigidity, and transparency, and also has a good appearance. [Means for Solving the Problems] The present invention provides a catalyst component obtained by supporting titanium tetrachloride on magnesium halide containing an organic compound having a C-O or C-N bond, an organoaluminum compound, and an organic acid. (a) white kerosene soluble content at 30°C is 20% by weight or less and its ethylene content is 20% by weight or less, and (b) the ethylene content of the entire polymer is 2 to 7. M w /M o is obtained by dividing the molecular weight distribution curve measured by GPC, with the horizontal axis expressed as the natural logarithm of the molecular weight, into three, and approximating the molecular weight distribution curve on the lower molecular weight side _with a Gaussian distribution _. is 5.0 or less, and the melt flow index is 0.2 to 20 g/
The present invention relates to an ethylene-propylene random copolymer for film, characterized in that the processing time is 10 min. The copolymer of the present invention needs to have a) white kerosene soluble content at 30°C of 20% by weight or less. That is, 10 g of the copolymer was completely dissolved in white kerosene containing 0.2% by weight of antioxidant at 120 to 130°C, then the temperature was lowered to 30°C over 4 to 5 hours, and then left at 30°C for 2 hours. It is then filtered to remove the white kerosene-soluble portion. The soluble portion is then poured into a methanol-acetone mixed solvent to make it insolubilized, and the resulting insoluble portion is filtered off. This filter residue is the part that is soluble in white kerosene at 30°C. If the 30°C soluble portion exceeds 20% by weight, the copolymer will have poor rigidity, which is not preferred. Moreover, if the ethylene content of the part exceeds 20% by weight, the transparency of the copolymer will be poor. The preferred range is that the white kerosene soluble content is 5 to 15% by weight, and the ethylene content of this part is 5 to 18% by weight. The copolymer of the present invention has (b) an ethylene content of 2 to 2;
It needs to be 7% by weight; if it is less than 2% by weight, the impact resistance will be poor, and if it exceeds 7% by weight, the rigidity will be poor. The copolymer of the present invention c) measured by GPC,
The molecular weight distribution curve whose horizontal axis is represented by the natural logarithm of the molecular weight is divided into three parts, and the molecular weight distribution curve on the lower molecular weight side is approximated by a Gaussian distribution, and M _w /M _o is required to be 5 or less. This method of measuring M _w /M _o is published in the Journal of
Chromatographic Science, Vo120, June
1982, 252-255. G.P.C.
is measured at 135°C using trichlorotoluene as the mobile phase. The separation power of the column may be as long as, for example, two Shodex AD80MS manufactured by Showa Denko connected together. As shown in the attached drawing, the molecular weight distribution curve with the horizontal axis expressed in ln (molecular weight) is divided into three parts: a: high molecular weight side (1/3), b: near the peak (1/3), c: low molecular weight side (1/3). The molecular weight distribution curve is divided into three parts in detail as follows. GPC shown in the drawing
For the elution amount of the elution curve, determine three points (X _n , X ₁ and X ₂ ) on the horizontal axis corresponding to the peak position and the detection limit positions on the high molecular weight side and low molecular weight side, respectively, and calculate the distance from X _n . Select the detection limit position (X ₂ in the example in the drawing) that has a large detection limit, and divide the length between X ₂ and X _n into three equal parts, and then divide the length between X ₂ and
The measurement is performed by dividing the horizontal axis toward the other detection limit position (X ₁ ) into three regions: a low molecular weight region c, a peak region b, and a high molecular weight region a. The molecular weight distribution curve of the c region thus obtained is approximated by the following formula.
Find M _w /M _o . Y=Y _n・exp[−(X−X _n ) ² /2S ² ] Y: Height when the natural logarithm of molecular weight ln (molecular weight) is X Y _n : Natural logarithm of peak molecular weight ln (peak molecular weight)
Height S when is X _n : √ ( _{w o} ) If M _w /M _o measured by the above method exceeds 5, the surface will become cloudy or sticky when made into a film, which is undesirable. The lower limit of M _w /M _o is not particularly limited, but theoretically it is 1.0, and usually it is 2 or more depending on the properties of the polymer. The copolymer of the present invention, like the conventional ethylene/propylene random copolymer, has a melt flow index of about 0.2 to 20 g/10 min, usually 1.5.
~12g/10min. This corresponds to an intrinsic viscosity [η] of 1.3 to 3.1, and therefore a molecular weight of 180,000 to 54
Equivalent to 10,000. The copolymer of the present invention is a catalyst comprising a catalyst component obtained by supporting titanium tetrachloride on magnesium halide containing an organic compound having a C-O or C-N bond, an organoaluminum compound, and an organic acid ester. copolymerized with ethylene at 50-70°C in liquid propylene containing aromatic hydrocarbons using
It is then obtained by washing with propylene. EXAMPLES The present invention will be explained in more detail with reference to Examples below. In Examples and Comparative Examples, physical properties were determined by using a phenolic stabilizer at a weight ratio of 20/10,000, calcium stearate at a weight ratio of 10/10,000, and a lubricant at a weight ratio of 20/10,000 for the produced ethylene/propylene copolymer. Added at a weight ratio of 10000,
The thickness of the copolymer obtained by granulating at 250℃ at 240℃
A T-die film of 30μ and width 25cm was made and evaluated. The measurement method is as follows. Melt flow index (g/10min): 230
°C, load 2.16 kg, according to ASTM D-1238-62T. Haze (%): According to ASTM 1003-53. Blocking: Layer two films together,
Calculate as a percentage of the contact area after placing a kg weight on it and keeping it at 50℃ for 24 hours. Young's modulus (Kg/mm ² ): Measured using a 20 mm x 220 mm film with non-stron. Tensile strength (Kg/cm ² ): According to ASTM D882-64T. Low temperature impact resistance (Kg・cm/mm): 10cm x 10cm at 5℃
It is calculated from the impact energy when a spherical weight is applied to the film and it breaks. Embossment: Visually judge after holding the film at 50°C for 24 hours. Example 1 1 Synthesis of catalyst A vibratory mill equipped with four crushing pots each having an internal volume of 4 and containing 9 kg of hard balls each having a diameter of 12 mm was prepared. 300 g of magnesium chloride in each pot under nitrogen atmosphere,
60 ml of tetraethoxysilane and 45 ml of α,α,α-trichlorotoluene were charged and pulverized for 40 hours.
3 kg of the above-mentioned pulverized material and 20 kg of titanium tetrachloride were placed in a sufficiently dried autoclave under a nitrogen atmosphere, and after stirring at 80°C for 120 minutes, the mixture was allowed to stand and the supernatant liquid was removed. Then add 35% of n-heptane and add 80% of n-heptane.
After stirring at °C for 15 minutes, the mixture was allowed to stand and the washing operation to remove the supernatant liquid was repeated 7 times, followed by further addition of 20 g of n-heptane to form a solid catalyst slurry. A portion of the solid catalyst slurry was sampled, n-heptane was evaporated, and analysis revealed that the solid catalyst contained 1.9 wt% titanium. 2. Polymerization Reaction 25 kg of propylene and 2.5 kg of toluene were charged into a jacketed autoclave which had been thoroughly dried, purged with nitrogen, and further purged with propylene. Meanwhile, in flask 1, add 500 ml of n-heptane.
Add 2.6 ml of diethylaluminum chloride, 1.4 ml of methyl P-toluate, and 1 g of the above solid catalyst,
After stirring for 1 minute at room temperature, triethylaluminum
0.5 ml was added and press-fitted into the above 100 autoclave. After starting the charging of hydrogen and ethylene, the internal temperature was maintained at 65°C by pouring hot water into the jacket, and hydrogen and ethylene were charged so that the gas phase concentration of hydrogen was 6 vol% and the ethylene gas phase concentration was 2.5 vol%. Polymerization continued while adding On the other hand, 56.5 ml of n-
3.5ml of triethylaluminum dissolved in heptane at 0.5ml/min, propylene at 125g/min.
Polymerization was continued for 2 hours while being continuously pressurized into the autoclave at a rate of min. After 2 hours, add 10 ml of diethylene glycol monoisopropyl ether, stir at 60℃ for 30 minutes, and then add 10 ml of diethylene glycol monoisopropyl ether and stir for 30 minutes at 60°C.Then, the inner diameter of the thin part is 10 cm, the inner diameter of the thick part at the top is 30 cm, the length of the thin part is 10 m, and the thick part at the top. Slurry was introduced at a rate of 30 kg/h into the upper part of a countercurrent washing tower with a length of 2 m, and a cleaning liquid with a composition of 95% propylene and 5% toluene was introduced from the bottom at a rate of 40 kg/h.
Kg/h, slurry washed from the bottom 26Kg/h
The slurry was taken out through a double tube with an inner diameter of 3/4 inch and a length of 60 m, and then discharged into a cyclone maintained at atmospheric pressure to separate the polymer. The obtained polymer was further dried at 20 mmHg and 80°C for 4 hours, yielding 15 kg of powder.
The obtained powder was evaluated by the method described above. The results are shown in the table. Comparative Example 1 The same procedure as Example 1 was carried out except that toluene was not used during the polymerization. The results are shown in the table. Comparative Example 2 At the initial stage of polymerization, propylene was used alone,
After 1 hour and 30 minutes of polymerization, the gas phase concentration of ethylene was
Example 1 except that the polymerization was further increased to 8.5 vol% for 30 minutes.
I did the same thing. The results are shown in the table. Comparative Example 3 The same procedure as Example 1 was carried out except that tetraethoxysilane was used instead of methyl toluate during polymerization.
The results are shown in the table. Example 2 The same procedure as in Example 1 was carried out except that the amount of toluene used was 4 kg and the concentration of ethylene in the gas phase was 3.0 vol%. The results are shown in the table. Example 3 The same procedure as Example 1 was carried out except that the polymerization temperature was 70°C and the deactivation temperature was 50°C. The results are shown in the table. Comparative Example 4 The same procedure as in Example 1 was carried out except that 1 kg of hexane was used instead of toluene during polymerization. The results are shown in the table.

[Table] Notes: *Based on known measurement methods.

[Brief explanation of the drawing]

The drawing shows the molecular weight distribution curve used in the present invention.
FIG. 2 is an explanatory diagram showing a dividing method. In the figure, a is the high molecular weight side (1/3) region, b is near the peak (1/3)
The region c represents the low molecular weight side (1/3) region.

Claims (1)

[Claims] 1. A catalyst consisting of a catalyst component obtained by supporting titanium tetrachloride on magnesium halide containing an organic compound having a C-O or C-N bond, an organoaluminum compound, and an organic acid ester. (b) The ethylene content of the entire polymer is 2 to 7% by weight; The molecular weight distribution curve measured by GPC, where the horizontal axis is expressed as the natural logarithm of the molecular weight, is divided into three parts, and the molecular weight distribution curve on the lower molecular weight side is approximated by a Gaussian distribution. M _w /M _o is 5.0 or less, 2 Melt flow index is 0.2~20g/
10 min. An ethylene-propylene random copolymer for film use.