JPH0425134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a biaxially stretched polypropylene film that has excellent rigidity, transparency, and oil resistance. Biaxially stretched polypropylene film has excellent tensile strength, rigidity, transparency, oil resistance, and electrical properties, so it is used as a film for various packaging applications.
It is also widely used in electrical components such as capacitors. On the other hand, recently there has been a strong desire to further improve the excellent physical properties of the above-mentioned biaxially oriented polypropylene film. For example, in the cigarette packaging field, when switching from cellophane to biaxially oriented polypropylene film, it is necessary to further improve the rigidity and transparency. Improvements are requested. Furthermore, further improvement in oil resistance is desired for use in condenser films, for example. The inventors of the present invention have conducted extensive studies in view of these points, and have found that if a polypropylene resin composition having specific physical properties is used, the resulting biaxially stretched polypropylene film will have even better rigidity, transparency, and oil resistance. We have discovered that this is the case, and have arrived at the present invention. That is, the present invention provides for sequential extraction with boiling diethyl ether, boiling n-hexane, and boiling n-heptane,
Boiling diethyl ether soluble matter is 1.0% by weight or less,
The boiling n-hexane soluble matter in the boiling diethyl ether insoluble matter is 1.0% by weight or less, the boiling n-heptane soluble matter in the boiling n-hexane insoluble matter is 0.8% by weight or less, and the limit of the above soluble matter The viscosity [η] is
0.5dl/g or less, 0.4dl/g or less, and 0.3dl/g
It is a polypropylene biaxially stretched film made using a polypropylene resin composition having the following molecular weight distribution / of 5 or less. Boiling diethyl ether in the present invention, boiling n
- The sequential extraction method using hexane and boiling n-heptane is as follows. After completely dissolving 5 g of a polypropylene resin composition sample in 500 ml of tetralin at 160°C, it was gradually cooled to 20°C over 3 hours, and then dissolved in acetone.
1.5 to completely precipitate polypropylene,
Pass and dry. The obtained polypropylene powder was first subjected to Soxhlet extraction with 120 ml of diethyl ether for 6 hours to separate insoluble and soluble components. Next, the boiling diethyl ether insoluble matter was subjected to Soxhlet extraction with 120 ml of n-hexane for 13 hours to separate the insoluble matter and the soluble matter. Finally, add 120ml of n-heptane to the boiling n-hexane insoluble matter.
Soxhlet extraction was performed for 13 hours to separate insoluble and soluble components. In the present invention, it is necessary that the ratio of the above-mentioned various boiling solvent soluble substances and the intrinsic viscosity [η] (hereinafter simply referred to as [η]) measured in tetralin at 135° C. be within specific ranges. That is, regarding the proportion of soluble matter, boiling diethyl ether soluble matter is 1.0% by weight or less, and boiling n-hexane soluble matter in boiling diethyl ether insoluble matter is 1.0% by weight or less.
The content of boiling n-heptane solubles in boiling n-hexane insolubles is 0.8% by weight or less.
If it is outside these ranges, the biaxially stretched film will not have sufficient rigidity and oil resistance. In addition, [η] of each soluble substance is 0.5 dl/g or less for boiling diethyl ether soluble content, 0.4 dl/g or less for boiling n-hexane soluble content, and 0.3 dl/g for boiling n-heptane soluble content. g or less. If it is outside these ranges, the biaxially stretched film will not have sufficient transparency. In the present invention, the molecular weight distribution is determined by gel permeation chromatography.
The molecular weight was determined by calibrating the molecular weight using a monodisperse polyethylene molecular weight standard. In the present invention, the value of / must be 5 or less, and if this value exceeds 5, the transparency will be insufficient. Melt Flow Index MI (ASTM D-
1238-65T, at a temperature of 230°C and a load of 2.16 kg) is not particularly limited, but is preferably 0.5 to 10 g/10 minutes, particularly preferably 1.0 to
It is 4.0g/10 minutes. If the MI value is less than 0.5 g/10 minutes, the film forming property is poor, and the MI value is less than 10 g/10 minutes.
If the time exceeds 10 minutes, the strength of the biaxially stretched film will become insufficient. The method for producing polypropylene used in the present invention is not particularly limited as long as it satisfies the physical properties described above, but as an example, titanium tetrachloride is reduced with diethylaluminium chloride, then treated with diisoamyl ether, and then titanium tetrachloride is titanium trichloride composition catalyst treated with an organoaluminum compound (e.g. diethylaluminum chloride)
A method of reducing the molecular weight of polypropylene polymerized using a catalyst system in combination with a third component (for example, an ether, ester, phosphite compound, etc.) if necessary is mentioned. In the present invention, commonly used antioxidants, ultraviolet absorbers, anti-blocking agents, slip agents, antistatic agents, coloring agents, etc. are added to the polypropylene resin composition, and the film is formed using a T-die or the like. After that, it is made into a biaxially stretched film by the usual two-stage stretching or simultaneous biaxial stretching. Hereinafter, the present invention will be explained in more detail with reference to Examples. The physical properties of the film were measured as follows. Haze: Conforms to ASTM D-1003-53. Young's modulus: A test piece with a width of 20 mm was sampled from the longitudinal direction (MD) and the transverse direction (TD), and the stress strain curve was measured using a tensile tester at a chuck interval of 100 mm and a tensile strength of 300 mm/min. Expressed as a percentage. Tensile strength: According to ASTM D-882-64T. Oil resistance: JIS 5cm x 5cm x 25μ film
After soaking in No. 1 oil at 80℃ for 24 hours, take it out, wash with JIS No. 1 oil, and dry. It is indicated by the weight increase rate at that time. Example 1 In an autoclave with an internal volume of 200 mL, 100 mL of n-heptane was charged under a nitrogen atmosphere, and then a commercially available titanium trichloride catalyst (manufactured by Marubeni Solvay Co., Ltd. 01F) 19
g and 59 g of diethylaluminum chloride were charged. After removing the nitrogen in the autoclave with a vacuum pump and charging propylene and hydrogen, the temperature was started to increase and the pressure of the polymerization machine was set to 7.9Kg/cm ² at 60℃, and the hydrogen concentration in the gas phase was 1.0vol%. Propylene and hydrogen were continuously charged to maintain the temperature, and polymerization was continued for 1.5 hours. After the polymerization was completed, methanol 62 was charged to stop the polymerization, and the mixture was purified and dried by a conventional method to obtain 38 kg of powdered polymer. This powdery polymer contains 0.25 wt% of 3,5-ditertiary-butyl-4-hydroxytoluene, 0.05 wt% of calcium stearate, and tetrakis-
[Methylene-(3,5-ditertiarybutyl-4
-Hydroxyphenyl)propionate]methane
0.10 wt% and 0.009 wt% of 2,5-dimethyl-2,5-ditertiarybutyl peroxyhexane were uniformly mixed and pelletized. Next, the pellets were processed using a T-die film forming machine.
Extruded at 250℃, cooled with a cooling roll at 50℃,
A sheet with a thickness of 750 μm was created. this sheet
The film was stretched 5 times in the machine direction (MD) and then 7 times in the transverse direction (TD) at 150° C. using a TM long biaxial stretching machine, and then heat-set to obtain a biaxially stretched film with a thickness of 25 μm. The physical properties of this film were measured and the results were
Shown in the table. Also, MI of the resin composition (pellet) used,
The results of sequential extraction with Mw/ and solvent are also shown in Table 1. Example 2 Polymerization temperature was 55℃, hydrogen concentration in gas phase was 1.2vol
%, and the polymerization time was changed to 2 hours, but the same procedure as in Example 1 was carried out, and the results shown in Table 1 were obtained. Example 3 Polymerization temperature was 65°C and hydrogen concentration in the gas phase was 0.8vol.
%, and the polymerization time was changed to 1 hour, but the same procedure as in Example 1 was carried out, and the results shown in Table 1 were obtained. Comparative Example 1) Synthesis of Transition Metal Catalyst A A vibratory mill equipped with four grinding pots each having an internal volume of 4 and containing 9 kg of steel balls with a diameter of 12 mm is prepared. 300 g of magnesium chloride in a nitrogen atmosphere in each pot.
60 ml of tetraethoxysilane and 45 ml of α, α, α-trichlorotoluene were added, and the mixture was pulverized for 40 hours. Put 300g of the above co-pulverized material into flask No. 5,
Add 1.5 titanium tetrachloride and 1.5 toluene and bring to 100°C.
The mixture was stirred for 30 minutes. Next, leave it to stand, remove the supernatant liquid, and add 1.5 titanium tetrachloride and 1.5 toluene in the same manner.
was added and stirred at 100° C. for 30 minutes, and then the supernatant liquid was removed and the solid content was further washed with n-heptane in step 4, which was repeated 10 times to obtain a slurry of transition metal catalyst A. ) Polymerization reaction and physical property evaluation 100 g of n-heptane was charged under a nitrogen atmosphere into an autoclave with an internal volume of 200 g, and then 4 g of transition metal catalyst A and diethylaluminium chloride were added.
17 ml, methyl p-toluate 8 ml, and triethylaluminum 4 ml were charged. After removing the nitrogen inside the autoclave with a vacuum pump and charging propylene and hydrogen, the temperature was started to rise and the pressure of the polymerization machine was increased to 75℃.
Propylene and hydrogen were continuously charged so as to maintain the hydrogen concentration in the gas phase at 7.9 Kg/cm ² and 0.3 vol%, and polymerization was continued for 2 hours. After the polymerization was completed, methanol 62 was added to stop the polymerization, and the mixture was purified and dried using a conventional method.
38Kg of powdered polymer was obtained. Below, when pelletizing a powdery polymer, 2.
Example 1 except that 5-dimethyl-2,5-ditertiarybutylperoxyhexane was not added.
The same procedure as above was carried out, and the results shown in Table 1 were obtained. Comparative Example 2) Synthesis of Transition Metal Catalyst B Titanium tetrachloride was reduced and ground with aluminum in the presence of aluminum chloride in a vibrating mill with an internal volume of 600 ml containing 80 steel balls with a diameter of 12 mm.The composition was approximately TiCl ₃ - 30 g of a eutectic of titanium trichloride and aluminum trichloride equal to 1/3 AlCl ₃ , 1.5 g of diphenyl ether and 0.6 g of titanium tetrachloride were charged and ground for 14 hours at room temperature under nitrogen atmosphere. The contents were separated from the steel balls under a nitrogen atmosphere to obtain a titanium trichloride composition. 20g of this titanium trichloride composition was mixed with n-heptane.
After stirring for 30 minutes at 80° C. using 200 ml, n-heptane was removed by decantation. next,
100 ml of n-heptane was added to this to obtain a slurry of transition metal catalyst B. ) Polymerization reaction and physical property evaluation 40g of transition metal catalyst B was used in place of the titanium trichloride catalyst manufactured by Marubeni Solvay, the amount of diethylaluminium chloride charged was 62g, and the hydrogen concentration in the gas phase was 2.2vol%. 2,5-dimethyl-
The same procedure as in Example 1 was carried out except that 2,5-ditertiarybutylperoxyhexane was not added.
The results shown in Table 1 were obtained. 【table】

Claims (1)

[Claims] 1. In sequential extraction with boiling diethyl ether, boiling n-hexane and boiling n-heptane, boiling diethyl ether soluble matter is 1.0% by weight.
Below, boiling n in boiling diethyl ether insoluble matter
- Hexane soluble matter is 1.0% by weight or less, boiling n-
Boiling n-heptane soluble matter in hexane insoluble matter is
0.8% by weight or less, and the intrinsic viscosity [η] of the above-mentioned soluble materials is
0.5dl/g or less, 0.4dl/g or less, and 0.3dl/g
A polypropylene biaxially stretched film obtained using a polypropylene resin composition having the following molecular weight distribution: 5 or less.