JP3369253B2 - Polymer insulating material and molded body using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to polymeric insulating materials having excellent electrical properties. More specifically, the present invention relates to a polymer insulating material having specific electrical properties and having excellent electrical insulation properties, and a molded product using the same. More specifically, the present invention relates to a polymer insulating material having excellent electrical properties even when it is made thin, and to a thin molded product obtained from this material.

[0002]

2. Description of the Related Art Polymer materials such as polyolefins, polyesters, polyvinylidene fluoride, silicone resins, epoxy resins and polystyrenes generally have a low electric conductivity, and their electrical properties such as insulating properties are utilized to make a great number of kinds. Used as an electric material. In addition to their excellent electrical insulation properties, these polymeric materials have characteristics such as flexibility, heat resistance, and hydrophobicity, so polymeric materials have been used in many products. .

[0003]

Polyolefins, especially polypropylene, are easy to mold and process, have excellent electrical, mechanical and chemical properties, and can be obtained at low cost. Very well used as a material. For example, it is widely used as an electret material in the form of a filter or a film, or is widely used as an electric insulating tape or a covering material, or a biaxially stretched film as an electric insulating material such as an insulating film for a capacitor. The higher the insulation resistance of polypropylene used for these is, the better, and the higher the dielectric breakdown strength is, the higher the performance of the product is obtained.

However, the insulating properties of the polypropylene currently used cannot be said to be very excellent, and it would be industrially extremely beneficial if polypropylene having higher insulating properties could be produced. For such a purpose, high-purity polypropylene has been conventionally studied. For example, in JP-A-61-110906, JP-A-59-63609 and JP-A-58-188627, the proportion of stereoregularity of polypropylene is increased and the boiling n-heptane soluble content is decreased to increase the crystallinity. As a result, it is disclosed that the dielectric breakdown strength of the biaxially oriented polypropylene is increased. Further, in JP-A-62-113548, JP-A-1-254748, JP-A-1-166955, JP-A-2-150443, etc., it is possible to reduce the catalyst residue and chlorine content remaining in polypropylene as much as possible. Improvements in insulation properties have been made.

However, there is a problem that the cost is increased when such an improved high-purity polypropylene is industrially produced, and when the stereoregularity is increased, the crystallinity is increased and the molded product becomes hard. It tends to occur and the molding processability deteriorates. For example, it is difficult to spin at the time of spinning, breakage occurs at the time of stretching, and voids are generated at the time of film molding, so that only a molded product with poor insulation properties can be obtained as a result. There was a problem. In reality, it is very difficult to completely remove impurities, and a large amount of residual impurities from catalysts and the like are contained.

Further, in the conventional method, when it is used as an insulating material for a capacitor film, for example, there is a strong demand for miniaturization of electric parts and electronic parts using the same,
In order to solve this, it is desired to increase the dielectric breakdown resistance of the capacitor film to make the film thin and downsize.

However, a polypropylene stretched film obtained by the conventional method can have a considerably large dielectric breakdown resistance in the case of a film having a thickness of about 10 μm or more, but a unit of about 6 μm or less, particularly about 4 μm. It is difficult to obtain a thin film with a large dielectric breakdown resistance due to the drawback that the value of the dielectric breakdown resistance per thickness decreases extremely, and it has not been possible to solve the demand for miniaturization of electrical parts and electronic parts. There wasn't.

[0008]

Means for Solving the Problems The present inventors have solved the above problems and used as an electret material in the form of a filter or a film, or used as a biaxially stretched film as an electrically insulating material such as a capacitor film. In doing so, various studies were conducted on a polyolefin material that can be provided at a low cost without impairing the molding processability, and it was found that the electrical insulation characteristics were significantly affected by impurities contained in the polymer material. Impurities include catalyst residues and dust in the air.Among them, specific components affect the electrical insulation properties.If the amount and amount of the components are controlled, impurities such as catalyst residues will remain in the polymer relatively. However, it has been found to have good insulating properties. Further, it was found that polypropylene having a specific boiling n-heptane-soluble component had good electric insulation, rather than decreasing the boiling n-heptane-soluble component to increase the crystallinity as in the conventional method. The inventors have completed the present invention by finding that they have an excellent balance of properties and physical properties.

That is, according to the present invention, in the polymerization of polypropylene, the amount of polypropylene obtained is 300,000 g / g-Ti or more with respect to titanium in the catalyst, and the polypropylene used in the molded article is completely combusted in the air. The resulting ash content is 40 ppm by weight or less, titanium is 1 weight ppm or less in the ash composition, the chlorine content in the polypropylene is 2 weight ppm or less, and the boiling n-heptane-soluble content is 1 weight% or more. It is a polymer insulating material having a high dielectric breakdown voltage of 10% by weight or less.

The polypropylene, which is the polymer insulating material of the present invention, contains 6000 or less impurities of 1 μm or more and 10 μm or less and 100 impurities of 5 μm or more and 10 μm or less per cubic centimeter.
High-purity polypropylene containing no more than 10 μm and containing no impurities exceeding 10 μm is preferable.

Further, the present invention is a polypropylene molded article having a high electrical insulation property, which is obtained by stretching the above-mentioned or above polymer insulating material in at least one direction.

In the present invention, the dielectric breakdown voltage can be further increased by adding a specific additive to the polymer insulating material described above or above.

That is, according to the present invention, 1 weight p of an inorganic oxide or a hydroxide is added to the above-mentioned or above polymer insulating material.
It is a polymer insulating material having a high dielectric breakdown voltage obtained by adding pm or more and 10% by weight or less. As an inorganic oxide or hydroxide, an average particle size of 1 μm that does not include a particle size of 10 μm or more
The following magnesium, aluminum and iron oxides or hydroxides are preferable.

As additives, organic polysilane,
Maleic anhydride grafted polypropylene and a silane compound having an organic polyether group show excellent effects.

That is, according to the present invention, the organic polysilane is added to the above or above polymer insulating material in an amount of 50 ppm by weight to 10% by weight; or a maleic anhydride grafted polypropylene is added in an amount of 50 ppm by weight to 10% by weight. Alternatively, it is a polymer insulating material having a high dielectric breakdown voltage, which is obtained by adding a silane compound having an organic polyether in an amount of 50 ppm by weight or more and 10% by weight or less.

Further, the present invention is a polypropylene molded article having a high electrical insulation property, which is obtained by stretching a polymer insulating material having a high dielectric breakdown voltage, which is obtained by adding the above-mentioned various additives, in at least one direction.

Further, the present invention is an electrically insulating film obtained by biaxially stretching the above-mentioned various polymer insulating materials to which the above additives are added or not added.

In order to obtain polypropylene which is the polymer insulating material of the present invention, a solid titanium catalyst component containing titanium, magnesium, halogen and an internally added electron donating compound, and Group 1 or 2 of the periodic table, It is preferable to polymerize propylene in the presence of a polymerization catalyst consisting of an organometallic compound containing a metal selected from Group 3 and an externally added electron donating compound. By subjecting the polypropylene obtained by this polymerization method to dehalogenation treatment It is possible to obtain the particularly preferable polymer insulating material of the present invention.

In the electrically insulating film obtained by biaxially stretching the polymer insulating material of the present invention, particularly excellent effects of the present invention can be achieved when the thickness of the film is 1 to 6 μm. it can.

According to the method of the present invention, the amount of polypropylene obtained in the polymerization of polypropylene is 300,000 g / g-Ti or more, more preferably 1,000,000 g / g-Ti or more, and further preferably 1,000,000 g / g-Ti with respect to titanium in the catalyst. Is required to be 3,000,000 g / g-Ti or more.

Conventionally, it has been necessary to use polypropylene having a low ash content as the polypropylene used as the polymer insulating material. Therefore, a method for reducing the ash content by subjecting the polypropylene obtained by polymerization to a special post-treatment. It was possible to reduce the ash content of the polypropylene. However, in the polymerization process, the amount obtained was 300,000 with respect to titanium in the catalyst.
When the total ash content is reduced by devising a post-treatment for polypropylene having a content of less than g / g-Ti, a stretched film obtained from this polypropylene has a considerably large insulation in the case of a film having a thickness of about 10 μm or more. A film having a breakdown resistance can be obtained. However, when the thickness of the film is about 6 μm or less, particularly about 4 μm, the value of the dielectric breakdown resistance per unit thickness is extremely decreased, which causes a large dielectric breakdown resistance of a thin film. It is difficult to get things.

Although the cause is unknown, if the amount obtained in the polymerization process is not large with respect to titanium in the catalyst, even if the titanium component is largely removed as a whole by post-treatment to reduce ash content. The present inventors presume that there is a part where the titanium component remains without being removed, and that part becomes a defect that lowers the dielectric breakdown resistance when the film is thinned.

As a result of intensive investigations by the present inventors, the polypropylene used in the present invention must first have a titanium component sufficiently dispersed in the polypropylene formed in the polymerization process and not aggregated. To disperse into
The present invention has been completed by discovering that it is important to use, as a raw material, polypropylene obtained by polymerizing polypropylene obtained in a sufficiently large amount per titanium metal.

In the present invention, analysis of the ash composition requires that the content of titanium in polypropylene is 1 ppm by weight or less, preferably 0.5 ppm by weight or less, more preferably 0.3 ppm by weight or less. . If the amount of acquisition is low, it is necessary to remove titanium in the catalyst residue from the polypropylene obtained by polymerization, but the amount of acquisition of polypropylene per titanium in the process of polymerization is 1,
If it is, 000,000 g / g-Ti or more, it is not necessary to remove titanium in the catalyst component, and if the catalyst system and polymerization conditions are selected, the post-treatment of polypropylene obtained by polymerization can be greatly simplified. Will be possible.

There is no problem if the catalyst residue remaining in the polymer becomes very fine and dispersed in the polymer,
Among them, the titanium component easily aggregates, and the substance that has become a large nucleus cannot be removed by the post-treatment, which adversely affects the electrical characteristics. Therefore, even if the ash content obtained by burning polypropylene in the air is 40 ppm by weight or less, if the titanium content in the ash composition is 1 ppm by weight or more, the electrical characteristics are adversely affected. If the activity of the catalyst is not sufficiently high, the catalyst residue can be reduced by washing the polymer produced, but even in that case, if the titanium component is aggregated, even if the amount of residue is small, the electrical characteristics are adversely affected. give.

The polymer material of the present invention has an ash content of 40 ppm by weight or less, preferably 20 ppm by weight or less,
More preferably, it is 15 ppm by weight or less. 40 ash
When it exceeds the ppm by weight, the insulating property is deteriorated due to stretch breakage or voids generated when the fiber or film is processed.

In the case of the present invention, the amount of ash is larger than that in the case of removing the catalyst residue to a very small amount by post-treatment using polypropylene obtained as a raw material in the polymerization process in which the amount of acquisition per titanium is small as in the conventional method. Since it does not matter, the post-treatment can be simplified and the industrial profit is great.

The polymer insulating material of the present invention has a boiling n-heptane-soluble content of 1% by weight or more and 10% by weight or less, preferably 1.0% by weight or more and 9.0% by weight or less, more preferably 1.5% by weight or more. A polypropylene having a weight percentage of not less than 8.5 wt%. Here, the boiling n-heptane-soluble component is the amount of the n-heptane-soluble component obtained by extracting 2 g of polypropylene for 6 hours with boiling n-heptane using a Soxhlet extractor, expressed as a weight% based on the charged amount. Polypropylene with a boiling n-heptane-soluble content of less than 1% by weight has a high crystallinity, and the crystallinity is too high, and the molded product tends to be hard, and the moldability is poor, and the molded product has poor electrical insulation properties. I can't get it. Unlike the conventional findings, the polypropylene of the present invention does not deteriorate the electric insulating property even when the boiling n-heptane extraction residue is in the range of 95 to 90% by weight, and rather has good stretchability and gives a preferable result.

The boiling n-heptane-insoluble portion has an isotactic pentad fraction of 0.900 or more, preferably 0.92 or more, and more preferably 0.950 or more.

In the present invention, the chlorine content in polypropylene is 2 ppm by weight or less, more preferably 1 ppm by weight or less. It is known that ionic impurities have a bad influence on electrical characteristics, and among them, a trace amount of chlorine has a great influence, and the above-mentioned Japanese Patent Laid-Open Publication No. Sho 6-62.
2-113548, Japanese Patent Laid-Open No. 1-254749, Japanese Patent Laid-Open No.
-166955, Japanese Patent Laid-Open No. 2-150443 and the like. However, these references have a chlorine content of 10
When it is less than ppm, the effect on the dielectric loss factor is described, but the electrical insulation property is not described at all. Regarding the relationship between the chlorine content in the polymer and the electrical insulating property, it was found that the chlorine content in the polymer changed greatly at the boundary of 2 ppm by weight. That is, when the chlorine content exceeds 2 ppm by weight, the insulation characteristics deteriorate, but when the chlorine content becomes 2 ppm by weight or less, the insulation characteristics are significantly improved. Since the polymerization catalyst described below contains a large amount of chlorine, if the chlorine content is high even after washing, the chlorine in the polymer may be dechlorinated with an amine compound, epoxy compound, ammonia, organic fatty acid, etc. The content is preferably 2 ppm by weight or less.

Among these dechlorination treatments, the dechlorination treatment using an epoxy compound is particularly preferable. As the epoxy compound, alkylene oxides such as ethylene oxide, propylene oxide, butene oxide, cyclohexene oxide, glycidyl alcohol, glycidyl acid, glycidyl ester and the like are preferably used here. When a polymer is dechlorinated by using these epoxy compounds, OH of equimolar or more than the epoxy compound is used.
It is very effective to use a compound having a group. Examples of the compound having an OH group include water and alcohol compounds. The amount of the epoxy compound used is equimolar or more, preferably 2 times to 10,000 times, more preferably 10 times to 1,000 times, the molar ratio of chlorine contained in the polymer. . There are no particular restrictions on the dechlorination treatment of the polymer using an epoxy compound, whether it is a batch system or a flow system, and it is sufficient that the chlorine content and these compounds can be brought into contact with each other so that the reaction can easily occur. The temperature of the dechlorination treatment is not particularly limited, but it is usually room temperature to the melting point of the polymer or lower, and preferably 50 ° C to 100 ° C. The treatment time for performing the dechlorination treatment is the time required for completing the dechlorination reaction with the epoxy compound, and is usually 10 seconds to 1 hour, preferably 1 minute to 30 minutes. Further, the reaction product is preferably removed to the outside of the system, and the reaction product is removed by reducing the pressure or circulating air or nitrogen.

The polypropylene of the present invention needs to be subjected to a post-treatment to remove the catalyst residue when the amount of the polymer obtained per unit amount of the catalyst is low. Further, even when the activity of the catalyst is high and the amount of the polymer obtained is large, it is preferable to carry out a post-treatment to remove the catalyst residue. As a post-treatment method, polypropylene obtained by polymerization is liquid propylene,
Wash with butane, hexane or heptane. At this time, water, alcohol compound, ketone compound, ether compound, ester compound, amine compound, organic acid compound,
It is also possible to add an inorganic acid or the like to solubilize a catalyst component such as titanium or magnesium to facilitate extraction. It is also preferable to wash with a polar compound such as water or alcohol.

The dechlorination treatment is carried out before, during or after the above washing. When a dechlorination treatment is carried out before, during or after washing, these amine compound, epoxy compound, ammonia and organic fatty acid are added to the above solution to bring them into good contact with the polymer. Alternatively, it is also preferable to remove these solutions and then contact the polymer with these gaseous compounds. Furthermore, it is also preferable to add a stabilizer to the produced polymer and to add these compounds into the extruder when pelletizing using the extruder.

Here, polypropylene includes not only a homopolymer of propylene but also a random copolymer with one or more kinds of other unsaturated hydrocarbons or unsaturated silane compounds, or a block copolymer. Here, as the other unsaturated hydrocarbon, ethylene, 1-butene, 1-pentene, 3-methylpentene-1,1-pentene, 3-
Methyl butene-1,1-hexene, 4-methylpentene-1,5-ethylhexene-1,1-octene, 1-decene, 1-dodecene, vinylcyclohexene, styrene, allylbenzene, cyclopentene, norbornene,
5-Methyl-2-norbornene and the like, and examples of the unsaturated silane compound include allylsilane and the like. In this copolymer, the boiling n-heptane-soluble content is 1% by weight or more and 1
It is preferable that the proportion of the comonomer other than propylene is less than 10 wt% in the random copolymerization so as to be 0% by weight or less, and the polymerized portion of propylene alone occupies 50 wt% or more of the whole in the block copolymerization.

Further, a polymer other than polypropylene may be mixed and used. For example, a mixture of polypropylene and poly-α-olefins such as polybutene, polypentene, polyhexene, polyheptene, and polyoctene and polycyclopentene, cyclic polyolefins such as polynorbornene, and a copolymer of propylene and an olefin having 2 to 20 carbon atoms, A mixture with the above-mentioned other type of polymer is exemplified, but in the case of these mixed polymers, the ratio of the other type of polymer in the mixture is 30 wt% of the whole.
The following are preferred.

As the catalyst used for producing the polypropylene of the present invention, a catalyst which is industrially used for producing polypropylene is used. For example, titanium trichloride and an organoaluminum compound, or those obtained by supporting titanium trichloride or titanium tetrachloride on a carrier such as magnesium halide and an organoaluminum compound are used.

As a catalyst for producing polypropylene, it is preferable to use a catalyst having a high activity and originally containing a small amount of titanium component. Among the catalysts mentioned above, titanium trichloride on a carrier such as magnesium halide is more preferable than the titanium trichloride-based catalyst. It is preferable to use a catalyst system that supports titanium tetrachloride.

Above all, a transition metal catalyst component in which a compound containing a C--O or C--N bond as an internally added electron donating compound and a tetravalent titanium compound having at least one halogen are supported on a magnesium halide carrier, organic A catalyst composed of an aluminum compound and an externally added electron donating compound is preferred.

In such a catalyst, magnesium chloride, magnesium bromide, a complex thereof with an ether or a monoester, or a eutectic of magnesium chloride and magnesium bromide is used as the magnesium halide. Examples of the compound having a C—O or C—N bond used as the internally added electron donating compound include an ester, an ether, an orthoester, and an alkoxysilicon compound. Among them, ester compounds of aromatic acids such as benzoic acid and phthalic acid esters are preferable, and esters of phthalic acid and alcohol having 1 to 12 carbon atoms are particularly preferably used.

As the tetravalent titanium halide, halogen is preferably chlorine, and one in which a part of the halogen is changed to an alkoxy group can be used, but titanium tetrachloride is particularly preferably used. . The ratio of the aromatic acid ester to titanium halide used is 0.3: 1 to 1: 0.3, and more preferably 0.5: 1 to 1: 0.5. The ratio of titanium halide to magnesium halide is 1:
About 0.001 to 1: 0.5 weight ratio is preferable.

Esters, ethers, orthoesters, and alkoxysilicon compounds are used as the externally added electron-donating compounds. Specifically, esters of benzoic acid and benzoic acid having a nucleus substitution with alcohols having 1 to 10 carbon atoms, and Alkoxysilanes may be mentioned.

The alkoxysilane used here is
General formula: R _X Si (OR ′) _4-X (where R is a carbon number of 3 to
12 alkyl groups, R'is an alkyl group having 1 to 12 carbon atoms, and X is 1, 2, or 3).

Preferred externally added electron donating compounds are methyltrimethoxysilane, ethyltriethoxysilane, t-butyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane,
Cyclohexylmethyldimethoxysilane, dicyclohexyldimethoxysilane, 2-norbornanetriethoxysilane, 2-norbornanemethyldimethoxysilane, dicyclopentyldimethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentyldimethylmethoxysilane, tricyclopentylmethoxysilane, diisopropyldimethoxysilane, t-butyl There are methyldimethoxysilane and dinormalpropyldimethoxysilane,
More preferably, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, dicyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, t-butylmethyldimethoxysilane, dinormalpropyldimethoxysilane and the like are used.

The organoaluminum compound is preferably trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum and diethylaluminum chloride in which one or two hydrocarbon residues thereof are substituted with chlorine or bromine. And alkyl aluminum halogen such as dialkyl aluminum chloride such as dipropyl aluminum chloride and dihexyl aluminum chloride, and combinations thereof.

The ratio of the organoaluminum compound to the titanium in the transition metal catalyst component and the externally added electron donating compound used is 1: 1: 1 to 1: 10,000:
10,000 molar ratio, usually 1: 1 to 1,000:
The molar ratio is 1,000.

As a method for producing the titanium halide catalyst component supported on these magnesium halides, a known method can be used and there is no particular limitation, but a catalyst having a large activity, in particular, the amount of polypropylene obtained in the polymerization is 1,
, 000,000 g / g-Ti or more, particularly 3,000,0
It is preferable to obtain one having a value of 00 g / g-Ti or more.

These supported catalysts are preferable because they have a high activity and the magnesium chloride as a carrier is soft, and thus they are not finely dispersed after polymerization to cause aggregation of titanium.

In the polymerization, the temperature is usually room temperature to 150 ° C., and the pressure is normal pressure to 100 kg / cm ² . As a polymerization method, a conventional polymerization method such as a solvent polymerization method, a bulk polymerization method or a gas phase polymerization method is used. Particularly, the acquisition amount per titanium is improved so that the acquisition amount of the present invention is 300,000 g / g-
In order to satisfy Ti or more, the bulk polymerization method and the gas phase polymerization method are preferable.

As a method for quantifying the above ash, titanium and chlorine, known methods can be used. For example, as a method for measuring the ash content, first, about 1 to 100 g of a sample is used, and the sample is burned in a crucible or dish made of platinum, quartz or porcelain. Furthermore, after completely burning the carbon produced in the electric furnace at about 800 ° C. to make the crucible a constant weight, the weight of the remaining ash is calculated and the weight percentage of the sample is calculated. The ash composition can be obtained by using these ash by a usual analytical method such as an atomic absorption method, a fluorescent X-ray method, and a colorimetric method.

As a method for quantifying chlorine, sodium stearate is added to the sample and volatilized without burning, and after the ashing, chlorine collected as NaCl is extracted with water, and then colorimetrically determined with mercuric thiocyanate. Method (colorimetric method) or a method in which a sample is burned in a mixed gas stream of argon gas and oxygen gas, and the chlorine ions produced are titrated with silver ions produced coulometrically (coulometry method) ), Similarly, after burning the sample, a method of quantifying the generated chlorine ions by an ion chromatograph (ion chromatograph method), or irradiating the flat plate or tablet sample with X-ray Method of quantifying by fluorescent X-ray intensity (fluorescent X-ray method), method of quantifying radioactivity of chlorine radionuclide generated by nuclear reaction by irradiating a sample with thermal neutrons (radiation Analysis method), and the like.

A preferred application of the present invention is a stretched film as an electrically insulating film. The properties of this stretched film are greatly influenced by the properties of the raw material of the extruded film as the raw material. A stretched film as an electrically insulating film needs to have a high dielectric breakdown voltage, which requires a low number of impurities in the film. For that purpose, it is necessary to reduce the number of impurities in the raw material of the extruded film as a raw material. This impurity is mainly due to the catalyst residue, which can be evaluated by carefully observing the raw material of the extruded film under a microscope.

Here, as a method of counting the number of impurities in the original fabric, there is a method of counting the number of impurities using a microscope. However, it is very difficult to directly find impurities around 1 μm using a microscope,
First, the raw fabric is further stretched to form voids centering on impurities as a thin biaxially stretched film. By this operation, the size of the void is usually proportional to the draw ratio with the nucleus of the impurity as the center, so that the void can be easily found. Since the impurities are contained in this void, the impurities can be found by looking at the void in more detail. Specifically, 2 of 20 mmφ
Layer T die with sample polypropylene thickness 140μ
15 m after making the original fabric and preheating at 145 ° C for 1 minute,
Sequential stretching was carried out 5 times in the longitudinal direction and 7 times in the transverse direction at a stretching speed of cm / sec, and the film formed was found to have voids of 1 μm or more using a phase contrast microscope, and it was observed carefully to become the nucleus. The size of solid impurities present is measured, and the number per unit area is converted into the number of impurities having a diameter of 1 μm or more contained in one cubic centimeter of the original film of the extruded film.

In the method of the present invention, the number of impurities having a diameter of 1 μm or more and 10 μm or less contained in one cubic centimeter in the raw material of the extruded film is preferably 6000 or less, preferably 5000 or less, and 10 μm or less.
The presence of impurities with a diameter greater than m is not preferred.

These impurities are not limited to those derived from the residue of the catalyst, but may be mixed in during the polymerization process or molding process. Therefore, it is also necessary to prevent such contamination from occurring as much as possible.

In the present invention, the above polypropylene can be used as a polymer insulating material by a usual method. In the present invention, however, the polypropylene does not include a particle size of 10 μm or more, and an inorganic oxide or water having an average particle size of 1 μm or less is used. An oxide, an organic polysilane, a maleic anhydride graft polypropylene, and a silane compound having an organic polyether group can be added to further improve the dielectric breakdown resistance.

Conventionally, it has been said that impurities such as inorganic compounds should be extremely thin in order to use it as a polymer insulating material. Therefore, a complicated post-treatment method is used to remove ash from polypropylene obtained by polymerization. Applied and extremely costly methods have been implemented. However, in the present invention, it was found that the addition of the above-mentioned specific compound, on the contrary, can further improve the dielectric breakdown resistance.
This is amazing.

The reason why the dielectric breakdown resistance is improved by adding these additives is not clear so far, but these minute compounds probably have the effect of trapping electrons or conversely dispersing electrons. It is thought that The effect of these additives not only improves the dielectric breakdown voltage, but also imparts the property that the dielectric breakdown voltage does not decrease even at high temperatures. That is, normally, the dielectric breakdown voltage of the biaxially oriented polypropylene film is measured near room temperature, but the dielectric breakdown voltage at, for example, 80 ° C. to 100 ° C. is remarkably lowered as compared with the measured value near room temperature. It is known. The capacitor is repeatedly stored and discharged, which generates heat, and when it is actually used, the temperature becomes considerably higher than room temperature. In this case, the capacitor using the biaxially oriented polypropylene film has a lower dielectric breakdown voltage due to an increase in temperature, which adversely affects the performance of the capacitor. Although the polypropylene insulating material of the present invention has excellent performance by itself, it is possible to significantly improve heat resistance by adding the above-mentioned organic polysilane, maleic anhydride grafted polypropylene, or a silane compound having an organic polyether group. it can.

The present invention also relates to these polymeric insulating materials,
A polymer insulating material having a high breakdown voltage, which is obtained by adding an inorganic oxide or a hydroxide in an amount of 1 wt ppm or more and 10 wt% or less, preferably 30 wt ppm to 5 wt%, and more preferably 100 wt ppm to 5 wt%. Is. Here, the inorganic oxide or hydroxide is an oxide or hydroxide of magnesium, aluminum, iron having an average particle size of 1 μm or less, more preferably 0.1 μm or less, which does not include a particle size of 10 μm or more. Although the mechanism of the addition effect of these compounds is not known exactly, it has the effect of improving the electrical insulating property. Oxides or hydroxides of magnesium, aluminum, iron are industrially produced, powdery substances are available, and those with an average particle size larger than the above values are further crushed or classified. Can be used. Further, those which are surface-treated to improve dispersibility can also be used.

In addition, there is also a method in which a compound having a good dispersibility is previously dispersed in polypropylene in order to enhance the dispersibility and a compound of magnesium, aluminum or iron is converted into an oxide or a hydroxide by a chemical reaction. To be

Specifically, magnesium, aluminum,
Compounds such as iron halides, sulfates and organic acid salts can be converted into hydroxides and oxides by catalytic reaction with alkalis, amine compounds, oxirane compounds, ammonia and the like. These reactions can be performed in the liquid phase or the gas phase.

The present invention also relates to these polymeric insulating materials,
Dielectric breakdown obtained by adding a high molecular weight compound such as an organic polysilane, a maleic anhydride grafted polypropylene, or a silane compound having an organic polyether group in an amount of 50 wt% or more and 10 wt% or less, more preferably 100 wtppm or more and 5 wt% or less. It is a polymer insulating material with high voltage.

Here, the organic polysilane is a homopolymer, a copolymer or a terpolymer of an organic polysilane represented by the following general formula (1) whose main chain is silicon.

[0063]

[Chemical 1] (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are
Represents hydrogen, alkyl, aryl, alkoxy, silylalkyl, n, m and p are integers including 0 representing the proportion of monomer units in the polymer compound and represented by the following formula, n + m +
It represents an integer satisfying p ≧ 3. ) These organic polysilanes are industrially produced, and dehalogenation polycondensation of dihalogenated silanes with sodium or the like, polymerization of disilylene compounds or cyclic silane compounds, or monosilane dehydrogenation using transition metal compounds. It can be produced by polycondensation.

Specifically, polyphenylmethylsilane, polydiphenylsilane, polyphenylmethyl-co-dimethylsilane, polyphenylethylsilane, polydihexylsilane, polyphenylmethyl-co-diphenylsilane,
Polypropylmethylsilane, polydipentylsilane, polydi-t-butyl-co-dimethylsilane, polybutylmethylsilane, polydibutylsilane, polypentylmethylsilane, polydioctylsilane, polydodecylmethylsilane, polytrimethylsilylmethylsilane, polytriethylsilane Examples thereof include methoxysilylmethylsilane, polyphenylsilane, polycyclohexylmethylsilane, polycyanoethylmethylsilane, poly-2-acetoxyethylmethylsilane, poly2-carbomethoxyethylmethylsilane and the like.

The method of mixing the polysilane compound and the polyolefin is not particularly limited and may be a method of simply melt-mixing the two or a method of polymerizing the polyolefin using a catalyst containing polysilane and dispersing the polysilane. It is also possible to produce a masterbatch containing these polysilane compounds at a high concentration and then, if necessary, dilute and use another polyolefin so as to have an appropriate concentration.

The ratio of these polysilane compounds to polyolefin is preferably 50 ppm by weight to 10% by weight. More preferably 100 weight ppm or more 5
It is less than or equal to weight%. If the amount is less than 50 ppm by weight, the effect is small, and even if the amount exceeds 10% by weight, the effect is not particularly increased, and when the fiber or film is processed, stretch breaks or voids are generated and the insulating property is improved. It is not preferable because it may worsen.

The maleic anhydride-grafted polypropylene used in the present invention is industrially produced, and various grades are available, and maleic anhydride is added to polypropylene together with a radical generator and heated. Can also be manufactured by.

The graft ratio of maleic anhydride contained in the maleic anhydride-grafted polypropylene is 0.1% to 2
There is no particular limitation on the mixing method of the maleic anhydride grafted polypropylene and the polyolefin, and a method of simply mixing and melting the both, or a masterbatch containing these maleic anhydride grafted polypropylene at a high concentration is used. After production, it can be used by diluting it with another polyolefin to an appropriate concentration if necessary.

The ratio of these maleic anhydride-grafted polypropylene to the polyolefin varies depending on the grafting ratio of maleic anhydride, but the proportion of maleic anhydride-grafted polypropylene is 50 wt ppm to 10 wt%, more preferably 100 wt ppm or more. It is less than or equal to weight%. If the amount is less than 50 ppm by weight, the effect is small, and even if the amount exceeds 10% by weight, the effect is not particularly increased, and when the fiber or film is processed, stretch breaks or voids are generated and the insulating property is improved. It is not preferable because it may worsen.

The silane compound having an organic polyether group is a compound represented by the following general formula (2).

[0071]

[Chemical 2] (Wherein R ¹ represents the same or different hydrocarbon residue, R ² represents the same or different hydrocarbon residue, and n and m represent the ratio of the structural units in (), where m Is 0 or a natural number, n is a natural number of 1 or more, m + n is 1 or more and 1000 or less, and k is 0.
Alternatively, a natural number, 1 is a natural number of 1 or more. ) These silane compounds having a polyether group are industrially produced and can be easily obtained on the market. Specifically, tris (2-methoxyethoxy) vinylsilane,
Examples thereof include tris (2-methoxyethoxy) methylsilane, trimethoxysilyl (polyether), and polyether-modified silicone oil.

The method for mixing the silane compound having a polyether group and the polyolefin is not particularly limited, and a method in which both are simply melt mixed, or a polyolefin is polymerized using a catalyst containing a silane compound having a polyether group, Examples thereof include a method of dispersing a silane compound having a polyether group. It is also possible to prepare a masterbatch containing these polyether group-containing silane compounds at a high concentration and then, if necessary, dilute it with another polyolefin to an appropriate concentration before use.

The ratio of these silane compounds having a polyether group to polyolefin is 50 weight p.
Pm to 10% by weight is preferred. More preferably 10
It is 0 wt ppm or more and 5 wt% or less. 50 weight ppm
If the effect is small if it does not meet the requirements, the effect does not increase even if it exceeds 10% by weight, and the insulation characteristics deteriorate due to stretch breaks or voids generated during processing into fibers or films. It is not preferable because there is.

Another embodiment of the present invention is a polypropylene molded article having a high electrical insulating property, which is obtained by stretching the above-mentioned polymer insulating material in at least one direction.

The present invention is also an electrically insulating film obtained by biaxially stretching the above polymer insulating material.

The polymer insulating material of the present invention is used after being molded and processed, and is particularly used in the form of fiber or film. These molded products are preferably used as an unstretched film, a uniaxially stretched film and a biaxially stretched film. One of the embodiments of the present invention is a polypropylene molded article having a high electrical insulation property, which is formed by stretching a polymer insulating material in at least one direction. The method for stretching the film may be a known method and is not particularly limited, but a normal uniaxial stretching method or a roll stretching method, and a biaxial stretching method is an inflation method or a length method in which the stretching is performed in the length direction and the width direction at the same time. A tenter method in which the machine direction and the width direction are sequentially stretched can be used.

For example, in the tenter method, a melt film extruded by melting from a T-die is solidified by a cooling roll, the melt-formed film is preheated if necessary, and then introduced into a stretching zone, and then 1 at a temperature of 120 to 150 ° C. in the longitudinal direction. .5
Or stretched 8 times. This draw ratio is 1.5 to 8 times,
It is preferably 2 to 7 times, and if it is less than 1.5 times, the film strength does not increase, and if it exceeds 8 times, voids are likely to occur, strength in the width direction becomes low, and tearing easily occurs in the length direction. Then further 6 to 12 at a temperature of 140-170 ° C
Stretch twice in the width direction. Finally, the biaxially stretched film is optionally heat-set at 160 to 190 ° C.

The polymer insulating material of the present invention is a material having a very high electric insulating property by itself. However, in the case of a molded product using the same, a molded product such as a film or a fiber which is particularly stretched has a very high electrical insulation property. It is characterized by showing insulating properties. In particular, the film obtained by biaxial stretching has high mechanical strength and can be manufactured from thin to thick, and the material of the present invention is a thin film of 20 μm or less, preferably 10 μm or less, more preferably 1 μm to 1 μm. When a biaxially stretched film having a film thickness of 6 μm is formed, it shows better electric characteristics than when a known material is used.

When molding the molded product of the present invention, various stabilizers and additives used in ordinary polypropylene can be added to the polypropylene of the present invention.

In the present invention, the dielectric breakdown voltage was measured by the following method.

According to JIS-2330, Kasuga Electric Co., Ltd.
Using a direct current withstanding voltage tester, the range was set to 20 KV, a voltage was applied to the film at a voltage increase of 100 V / sec, the dielectric breakdown voltage was measured, and the withstand voltage characteristic was obtained. The breakdown voltage is the breakdown voltage measured value (V) divided by the film thickness (μm).

The film required for the measurement was obtained by extruding polypropylene pellets at 270 ° C. to prepare a sheet-like film having a thickness of 140 μm, and further heating this film at 150 ° C. using a TM Long biaxial stretching machine. First, MD
In the TD direction and then 7 times in the TD direction to a thickness of 4 μm
Was prepared. This film 150
The number of measurement points of the test piece was limited to one, using 50 pieces having a size of mm × 150 mm.

The measuring method is as follows. The upper electrode was a well-polished brass cylinder of 25 mmφ having a roundness of 3 mm around the (+) electrode, and the lower electrode was about 150 mm.
mm × 150 mm, 30 mm thick, 30 mm thick, placed on an elastic plate of rubber shore 60 to 70 degrees, and JIS-H-4
Thickness of 0.007mm or more and width of 80mm specified in 160
The aluminum foil of No. 1 was wrapped around, and this was used as the (-) electrode.

[0084]

EXAMPLES The present invention will be further described with reference to the following examples. Example 1 A vibration mill equipped with four grinding pots each having an inner volume of 4 liter and containing 9 kg of steel balls having a diameter of 12 mm was prepared. 300 g of magnesium chloride, 75 ml of diisobutyl phthalate, and 60 ml of titanium tetrachloride were added to each pot in a nitrogen atmosphere and pulverized for 40 hours.

10 g of the above co-ground product was placed in a 200 ml flask, 60 ml of toluene was added, and the mixture was stirred at 114 ° C. for 30 minutes and then left standing to remove the supernatant. Then n
-The solid content was washed with 100 ml of heptane three times at 20 ° C and dispersed in 100 ml of n-heptane to obtain a solid catalyst component slurry. The resulting solid catalyst component contained 1.9 wt% titanium and 14.2% diisobutyl phthalate.
It contained wt%.

An autoclave having an internal volume of 70 liters, which had been sufficiently dried and replaced with nitrogen, was prepared.
2 ml of triethylaluminum diluted to 1 ml, 0.8 ml of di-normal-propyldimethoxysilane and 150 mg of the above transition metal catalyst were added, and 20 kg of propylene and 17N hydrogen
1 was added and polymerization was carried out at 70 ° C. for 2 hours. After the polymerization, unreacted propylene was separated by decantation, and the polymerization product was washed with liquefied propylene three times. The product is then charged with water.
2 g and 10 ml of propylene oxide were added, and the mixture was further treated at 90 ° C. for 15 minutes and dried under reduced pressure for 5 minutes.
This treatment with propylene oxide is repeated 3 times,
The produced polymer was taken out and weighed 13.45k
g of polypropylene was obtained. The amount obtained per titanium in this polymerization was 4720,000 g-PP / g-Ti.

The intrinsic viscosity (hereinafter abbreviated as η) measured with a 135 ° C. tetralin solution of polypropylene is 1.6.
5. The boiling n-heptane extraction residual rate (weight of the extraction residual polymer / weight of the polymer before extraction expressed as a percentage, hereinafter abbreviated as II) measured by a Soxhlet extractor is 98.1.
%, The ratio of the weight average molecular weight and the number average molecular weight measured with 1,2,4-trichlorobenzene at 135 ° C. as a solvent by gel permeation chromatography (hereinafter, MW / MN
Abbreviated) was 5.5.

Irganox-1330 (trade name, Ciba-Geigy Co.) 0.2 part by weight, calcium stearate 0.0, based on 100 parts by weight of the obtained polypropylene.
02 parts by weight were mixed and pelletized at 250 ° C.

In order to measure the ash content of this polypropylene, 20 g of a sample was put into a porcelain crucible, ashed so as not to burn rapidly, and further put into an electric furnace at 850 ° C. to completely ash. When this was cooled in a desiccator dried and the ash content was measured, it was 14 ppm by weight. This was further analyzed and 0.2 ppm for titanium and 1.3 ppm for calcium.
It was ppm. The chlorine content in the pellets obtained in this example was 0.31 ppm.

The pellets are then extruded at 270 ° C.,
Sheet-like films having a thickness of 140 μm and 525 μm were obtained. Using a TM long biaxial stretching machine, this film was heated to 150 ° C., 5 times in the MD direction and then 7 times in the TD direction.
Double stretching was performed to prepare biaxially stretched films having thicknesses of 4 μm and 15 μm. The stretching stress when stretching a sheet-like film having a thickness of 140 μm is 35 k when it starts to be pulled in the TD direction.
g / cm ² , 42 kg / cm ² when stretched 7 times. The breakdown voltage of this film is 610V each
/ Μm, 725V / μm, tan δ are all 0.001
Met.

A 100 μm thick stretched film having a thickness of 4 μm was used.
The voids of 1 μm or more in cm ² were observed using a phase-contrast microscope, and the size and number of solid impurities forming the core were measured. As a result, 60 μm or more of impurities of 1 μm or more and 5 μm or less were found.
Pieces (converted to 1 cubic centimeter 1500
However, impurities exceeding 5 μm were not included.

The dielectric breakdown voltage of the 4 μm thick film at 80 ° C. was 534 V / μm. Example 2 300 g of anhydrous magnesium chloride, 1.6 liter of kerosene,
140 liters of 2-ethylhexyl alcohol
It heated at 3 degreeC for 3 hours, and set it as the uniform solution. 70 g of phthalic anhydride was added to this solution, and the mixture was stirred at 130 ° C. for 1 hour to dissolve it, and then cooled to room temperature. Furthermore, the solution cooled to the above room temperature was slowly added dropwise to 8.5 liters of titanium tetrachloride cooled to -20 ° C, and after the addition was completed, the temperature was raised to 110 ° C, and 215 ml of diisobutyl phthalate was added, and further 2
Stir for hours. The solid was separated by hot filtration, and the obtained solid was suspended again in 10 liters of titanium tetrachloride and stirred again at 110 ° C. for 2 hours. The solid was separated by hot filtration, and the obtained solid was washed with n-heptane until titanium was not substantially detected in the washing liquid. The obtained solid catalyst component was 2.3 wt% titanium and 1 diisobutyl phthalate.
It contained 1.6 wt%.

In the method of Example 1, triethylaluminum 4 diluted with 1000 ml of heptane as a catalyst was used.
ml, dinormal propyldimethoxysilane 1.6m
1. Polymerization was carried out using 300 mg of the above solid catalyst component. As a result of the polymerization, 9.97 kg of polypropylene was obtained, and the amount of acquisition per titanium by this polymerization was 1.45 million g-PP.
/ G-Ti.

This polypropylene was post-treated in the same manner as in Example 1 to obtain polypropylene powder. Η of this polypropylene powder is 1.70, II is 98.3%,
MW / MN is 5.1, ash content is 33 wt ppm, titanium 7
It was ppm and chlorine was 0.53 ppm.

Example 1 from this polypropylene powder
Biaxially stretched films having thicknesses of 4 μm and 15 μm were prepared in the same manner as in. The dielectric breakdown voltage of this film was 600 V / μm, 710 V / μm, and tan δ was 0.001.

It is to be noted that 100 μm of a stretched film having a thickness of 4 μm is used.
The voids of 1 μm or more in cm ² were observed using a phase-contrast microscope, and the size and number of solid impurities forming the core were measured. As a result, impurities of 1 μm or more and 5 μm or less were 12
0 (300 per cubic centimeter)
0 impurities are included, and there are 5 impurities (1
(75 per cubic centimeter) 10
Impurities exceeding μm were not included.

The dielectric breakdown voltage of the film having a thickness of 4 μm at 80 ° C. was 520 V / μm. Example 3 In Example 1, the polymerization conditions were set to 180 m for the solid catalyst component.
Polymerization was carried out in the same manner as in Example 1 except that g, triethylaluminum (1.5 ml) and di-normal-propyldimethoxysilane (0.4 ml) were used to obtain 15.28 kg of polypropylene. In this polymerization, the amount of polypropylene obtained per titanium was 4.47 million g-PP / g-Ti.

This polypropylene was post-treated in the same manner as in Example 1 to obtain polypropylene powder. Η of this polypropylene powder is 1.75, II is 92.7%,
MW / MN is 5.0, ash content is 9 wt ppm, titanium content is 0.
It was 2 ppm and chlorine 0.74 ppm.

Example 1 from this polypropylene powder
A biaxially stretched film was prepared in the same manner as. Thickness 140
Stretching stress when stretching a sheet-like film of μm is TD
The stretching property was 25 kg / cm ² when it started to be drawn in the direction, and 35 kg / cm ² when it was stretched 7 times, and the stretchability was very good. The breakdown voltage of this film is 640V each
/ Μm, 720 V / μm, tan δ are all 0.001
Met.

A 100 μm thick stretched film having a thickness of 4 μm was used.
The voids of 1 μm or more in cm ² were observed using a phase-contrast microscope, and the size and number of solid impurities forming the core were measured.
Pieces (1250 per cubic centimeter)
However, impurities exceeding 5 μm were not included.

The dielectric breakdown voltage of the film having a thickness of 4 μm at 80 ° C. was 548 V / μm. Comparative Example 1 13.2 kg of polypropylene was obtained in the same manner as in Example 1 except that water and propylene oxide were not added after the polymerization of polypropylene was completed (4.63 million g-PP / g-Ti). Amount of). Η of this polypropylene is 1.65, II is 98.0%, MW / M
N was 5.3. When the ash content of this polypropylene was measured, it was 16 ppm by weight. Further, when the amount of chlorine was measured, it was 3.6 ppm by weight. A film prepared by using this polypropylene powder in the same manner as in Example 1 has a dielectric breakdown voltage of 440 V / μ at a thickness of 4 μm.
m and a thickness of 15 μm were 635 V / μm.

It is to be noted that 100 μm of a stretched film having a thickness of 4 μm is used.
The voids of 1 μm or more in cm ² were observed using a phase-contrast microscope, and the size and number of solid impurities forming the core were measured.
Pieces (2000 when converted per cubic centimeter)
2) and 2 impurities of 5 μm or more and 10 μm or less (50 per cubic centimeter)
However, impurities exceeding 10 μm were not included.

The dielectric breakdown voltage of the film having a thickness of 4 μm at 80 ° C. was 395 V / μm. Comparative Example 2 An autoclave having an internal volume of 70 liters, which was sufficiently dried and purged with nitrogen, was prepared, and 1000 ml of heptane, 32 mmol of diethylaluminum chloride, 1.4 mmol of triphenylphosphite, and the above-mentioned transition used in Example 1 as a titanium catalyst were prepared. In place of the metal catalyst, 1.42 g of titanium trichloride solid catalyst (titanium tetrachloride reduced with an organic aluminum compound and activated with di-iso-amyl ether and titanium tetrachloride) was charged, and then 15 kg of liquefied propylene. Then, the temperature of the autoclave was raised after charging with hydrogen gas, and the polymerization was continued while stirring the temperature inside the autoclave at 60 ° C. for 4.5 hours. After 4.5 hours, propylene and hydrogen gas were purged. Subsequently, 8.5 liters of methanol, 14 liters of n-heptane and methyl acetoacetate 2
After charging 00 mmol, the catalyst component was solubilized at 110 ° C. for 2 hours. After separation, the operation of washing with 10 liters of water at 55 ° C. was repeated 4 times, and the produced polypropylene was filtered and dried to obtain 10.05 kg of polypropylene. The amount of polypropylene obtained per titanium metal in this polymerization reaction was 21,200 g / g-Ti.

Η of this polypropylene was 1.83, II was 99.3%, and MW / MN was 8.3. When the ash content of this polypropylene was measured, it was 5 ppm by weight and titanium was 1.5 ppm. Further, when the amount of chlorine was measured, it was 3 ppm by weight. A film prepared by using this polypropylene powder in the same manner as in Example 1 has a dielectric breakdown voltage of 405 V / μm at a thickness of 4 μm and a thickness of 15 μm.
Was 635 V / μm. The stretching stress when a sheet-like film having a thickness of 140 μm is stretched is 37 kg / cm ² when it is pulled in the TD direction and 47 k when it is stretched 7 times.
It was g / cm ² , and the drawability was poor.

It should be noted that 10c of a stretched film having a thickness of 4 μm
When observing voids of 1 μm or more in m ² using a phase-contrast microscope and measuring the size and number of solid impurities as the cores, 25 impurities of 1 μm or more and 5 μm or less (converted per cubic centimeter) Then 6250
7), and 7 impurities of 5 μm or more and 10 μm or less (converted per cubic centimeter are 175
0) included and 2 impurities exceeding 10 μm (500 when converted per cubic centimeter)
Was included.

The dielectric breakdown voltage of the film having a thickness of 4 μm at 80 ° C. was 320 V / μm. Comparative Example 3 An autoclave having an internal volume of 20 liters, which was sufficiently dried and replaced with nitrogen, was prepared, and 10 liters of heptane, 30 mmol of diethylaluminum chloride, and trichloride instead of the above transition metal catalyst used in Example 1 as a titanium catalyst were prepared. 2.5 g of titanium solid catalyst (titanium tetrachloride reduced with metallic aluminum and activated) was charged, and after hydrogen gas was further charged, the temperature was raised to 70 kg and 5 kg / cm ² −.
Polymerization was carried out by charging propylene gas so as to maintain G.
After 6 hours, the charging of propylene gas was stopped. The obtained polypropylene slurry was transferred to an autorelay having an internal volume of 70 liters, charged with 4.4 liters of methanol and 150 mmol of methyl acetoacetate, and solubilized at 110 ° C. for 2 hours. After separating, 55 with 5 liters of water
The operation of washing at ℃ was repeated 4 times, the produced polypropylene was filtered and dried to obtain 4.2 kg of polypropylene panda. The amount of polypropylene obtained per titanium metal in this polymerization reaction was 5040 g / g-Ti.

Η of this polypropylene is 1.83, II
Was 97.4% and MW / MN was 6.5. When the ash content of this polypropylene was measured, it was 16 ppm by weight and titanium was 3.5 ppm. Further, when the amount of chlorine was measured, it was 4 ppm by weight. A film prepared by using this polypropylene powder in the same manner as in Example 1 has a dielectric breakdown voltage of 390 V / μm at a thickness of 4 μm and a thickness of 15
It was 570 V / μm in μm.

10c of a stretched film having a thickness of 4 μm
When observing voids of 1 μm or more in m ² using a phase-contrast microscope and measuring the size and number of solid impurities which are the cores, 100 μm or more of impurities of 1 μm or more and 5 μm or less were measured.
Number of pieces or more (25 per cubic centimeter)
000) or more, 42 impurities (10500 when converted per cubic centimeter) of 5 μm or more and 10 μm or less, and 11 impurities (2700 when converted per cubic centimeter) exceeding 10 μm Was included.

The dielectric breakdown voltage of the 4 μm thick film at 80 ° C. was 310 V / μm. Example 4 Using the polypropylene powder of Example 1, based on 100 parts by weight of polypropylene powder, 2,6-di-t-
Butyl-p-cresol 0.1 part by weight, calcium stearate 0.005 part by weight, and Irganox-13
0.2 parts by weight of 30 (trade name, Ciba Geigy) was added and mixed, and then polyphenylmethyl-co-dimethylsilane (manufactured by Nisso Gosei Co., PPS-100: polyphenylmethylsilane dichloride and dimethylsilane dichloride). Was added at 3 parts by weight, and the mixture was extruded at 250 ° C. and pelletized. Then, the pellets were extruded at 270 ° C. to obtain a sheet-like film having a thickness of 140 μm. This film was stretched at 150 ° C. using a TM long biaxial stretching machine, firstly 5 times in the MD direction and then 7 times in the TD direction to prepare a biaxially stretched film having a thickness of 4 μm. The film thus obtained has a temperature of 23 ° C. and 80
When the dielectric breakdown voltage (hereinafter abbreviated as BDV) at ℃ was measured, the BDV was 641 V / μm and 585 V, respectively.
/ Μm. That is, BDV at room temperature was very high, and the rate of decrease of BDV at high temperature was also small. Example 5 The same procedure as in Example 4 was carried out except that the addition amount of polyphenylmethyl-co-dimethylsilane was changed to 0.1 part by weight based on polypropylene.
BDV at ℃ 641V / μm, 582V respectively
/ Μm. Example 6 The procedure of Example 4 was repeated except that 1 part by weight of polydihexylsilane obtained by reacting dihexylsilane dichloride with sodium metal in toluene at the boiling point of toluene was used in place of polyphenylmethyl-co-dimethylsilane. As a result, the BDVs of the obtained film at 23 ° C. and 80 ° C. were 638 V / μm and 583 V / μm, respectively. Example 7 Similar to Example 4 except that 1 part by weight of polymethylbutylsilane obtained by reacting methylbutylsilane dichloride and sodium metal in toluene at the boiling point of toluene in place of polyphenylmethyl-co-dimethylsilane was used. As a result,
The BDVs of the obtained film at 23 ° C. and 80 ° C. were 625 V / μm and 581 V / μm, respectively. Example 8 Based on 100 parts by weight of the polypropylene powder of Example 1, 0.1 parts by weight of 2,6-di-t-butyl-p-cresol, 0.005 parts by weight of calcium stearate, and Irganox-1330 ( (Product name, Ciba Geigy)
After 0.2 part by weight was added and mixed, 3 parts by weight of maleic anhydride-grafted polypropylene (maleic anhydride graft ratio 5%) was further added, and the mixture was extruded at 250 ° C. and pelletized.

The pellets are then extruded at 270 ° C.,
A sheet-like film having a thickness of 140 μm was obtained. This film was first subjected to M using a TM long biaxial stretching machine at 150 ° C.
Stretched 5 times in D direction and then 7 times in TD direction to give a thickness of 4μ
A biaxially stretched film of m was prepared. The BDVs at 23 ° C. and 80 ° C. of the film thus obtained were 636 V / μm and 589 V / μm, respectively. That is, BDV at room temperature is very high, and BDV at high temperature is hardly reduced. Example 9 A film obtained in the same manner as in Example 8 except that the amount added was changed to 50 ppm by weight based on polypropylene using maleic anhydride-grafted polypropylene (maleic anhydride graft ratio 8%) and 23 ° C. BDV at 80 ° C
Was measured to find that it was 635 V / μm and 584 V, respectively.
/ Μm. Example 10 A result was obtained in the same manner as in Example 4 except that trimethoxysilyl (polyether) was added in an amount of 0.1 part by weight with respect to polypropylene instead of polyphenylmethyl-co-dimethylsilane. 23 ℃ and 80 for 4μm thick film
BDV at ℃ are 615V / μm and 583V, respectively.
/ Μm. Example 11 The result was obtained in the same manner as in Example 4 except that 1 part by weight of tris (2-methoxyethoxy) methylsilane (LS-3660 manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of polyphenylmethyl-co-dimethylsilane. The BDV of the deposited film at 23 ° C and 80 ° C is 624 V / μm and 583 V / μm, respectively.
It was m. Example 12 Instead of polyphenylmethyl-co-dimethylsilane, polyether-modified silicone oil (TS manufactured by Toshiba Silicon Co., TS
F-160) was used in the same manner as in Example 4 except that 1 part by weight of F-160) was used.
The DV was 616 V / μm and 578 V / μm, respectively. Example 13 Instead of polyphenylmethyl-co-dimethylsilane, aluminum hydroxide (manufactured by Ishizu Pharmaceutical Co., Ltd., particle size S-100 of 10 μm
The average BDV at 23 ° C. of the obtained film was the same as in Example 4, except that the average particle size of 1 μm or less (excluding m or more) was added in an amount of 30 ppm by weight in the polymer. It was 635 V / μm. Example 14 Instead of polyphenylmethyl-co-dimethylsilane, magnesium hydroxide (manufactured by Kyowa Chemical Co., Ltd., Kisuma 5A particle size 10 μm)
The average BDV at 23 ° C. of the obtained film was the same as in Example 4, except that the average particle size of 1 μm or less (excluding m or more) was added in an amount of 30 ppm by weight in the polymer. It was 640 V / μm. Example 15 In place of polyphenylmethyl-co-dimethylsilane, iron oxide (manufactured by Showa Denko KK, Nanotite, ferric oxide having an average particle diameter of 0.02 μm) was added in an amount of 30 wt ppm in the polymer. As a result of carrying out the same procedure as in Example 4, the BDV of the obtained film at 23 ° C. was 655 V / μm. Example 16 A vibration mill equipped with four grinding pots having an inner volume of 4 liters and containing 9 kg of steel balls having a diameter of 12 mm was prepared. 300 g of magnesium chloride, 75 ml of diisobutyl phthalate, and 20 ml of titanium tetrachloride were added to each pot in a nitrogen atmosphere and pulverized for 40 hours. 200 g of the obtained co-ground product 10 g
Add it to a 60 ml flask and add 60 ml of toluene.
The mixture was stirred at 30 ° C. for 30 minutes and then left to stand to remove the supernatant. Then 100 ml of n-heptane 3 times at 20 ° C,
The solid content was washed and further dispersed in 100 ml of n-heptane to obtain a solid catalyst component slurry. The obtained solid catalyst component contained 0.1 wt% titanium and 14.2 wt% diisobutyl phthalate.

A fully dried autoclave with an internal volume of 3 liters, which had been purged with nitrogen, was prepared.
Was added, 5 g of triethylaluminum diluted with 100 ml of heptane, 2.5 ml of cyclohexylmethyldimethoxysilane, and 750 mg of the above solid catalyst component were added, and propylene was pressurized to 5 kg / cm ² -G to obtain 70
Polymerization was carried out at 0 ° C for 2 hours. After the polymerization, the reaction products were collected by filtration and dried under reduced pressure at 80 ° C. The obtained powder was subjected to contact treatment with a mixture containing 0.02 g of water per 1 g of propylene oxide at 90 ° C. for 15 minutes. 5 under reduced pressure
The drying treatment for 1 minute was repeated 3 times, and the produced polymer was taken out and weighed to obtain 599 g of polypropylene powder (B).

Η of this polypropylene (B) is 0.8
3, the ash content was 1.13% by weight. Of this, the mixture of magnesium oxide and magnesium hydroxide is 230 pp
m was included. Further, the amount of chlorine was measured by activation analysis and found to be 5.5 ppm by weight.

Polypropylene powder (B) containing a mixture of magnesium oxide and magnesium hydroxide was added to 100 parts by weight of polypropylene powder (A) obtained in the same manner as in Example 1 so that the total amount of magnesium was 30 ppm by weight. In addition, 0.1 parts by weight of 2,6-di-t-butyl-p-cresol, 0.01 parts by weight of calcium stearate and 0.2 parts by weight of Irganox-1330 are added and mixed. Extruded and pelletized at 250 ° C. The amount of chlorine in the pellet was measured by activation analysis and found to be 0.95 ppm by weight. Next, the film produced from the pellets in the same manner as in Example 1 had a dielectric breakdown voltage of 640 V / μm and a tan δ of 0.001.

[0114]

Industrial Applicability The polymer insulating material of the present invention has a high insulating property, particularly a high dielectric breakdown voltage, and the molded product obtained by stretching in at least one direction has a high dielectric breakdown voltage, and the electrical property is also high. It provides polypropylene with excellent physical property balance and is extremely valuable industrially.

─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 4-337309 (32) Priority date December 17, 1992 (December 17, 1992) (33) Priority claim country Japan (JP) (72) Inventor Yukio Ishii 1-6 Takasago, Takaishi-shi, Osaka Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Takeo Inoue 1-6 Takasago, Takaishi-shi, Osaka Mitsui Toatsu Chemical (72) Invention Researcher Tsutomu Iwatani, 1-6-6 Takasago, Takaishi-shi, Osaka, Mitsui Toatsu Chemical Co., Ltd. (56) References JP 62-122009 (JP, A) JP 48-100444 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) H01B 3/16-3/56 CA (STN) REGISTRY (STN)

Claims (15)

(57) [Claims] 1. The amount of polypropylene obtained in the polymerization of polypropylene is 300,0 with respect to titanium in the catalyst.
The ash content obtained by completely burning the polypropylene used in the molded body in the air is 4 g or more and is 4 g or more.
0 wt ppm or less, of the ash composition, titanium is 1 wt ppm or less, chlorine content in the polypropylene is 2 wt ppm or less, boiling n-heptane soluble content is 1 wt% or more and 10 wt% or less. Is a polymer insulating material with high breakdown voltage. 2. 1 included in 1 cubic centimeter
2. The polymer insulating material according to claim 1, which is made of high-purity polypropylene containing no more than 6000 impurities having a size of from 10 μm to 10 μm and no more than 1000 impurities having a size of from 5 μm to 10 μm and containing no impurities exceeding 10 μm. 3. The polymer insulating material according to claim 1 or 2, wherein the inorganic insulating material, the inorganic hydroxide, the organic polysilane, the maleic anhydride grafted polypropylene and the silane compound having an organic polyether group are used. A polymer insulating material having a high dielectric breakdown voltage, which is obtained by adding at least one additive. 4. The polymer insulating material having a high breakdown voltage according to claim 3, wherein the additive is an inorganic oxide or a hydroxide, and the addition amount is 1 weight ppm or more and 10 weight% or less. 5. The dielectric breakdown voltage, wherein the inorganic oxide or hydroxide according to claim 4 is an oxide or hydroxide of magnesium, aluminum, iron having an average particle size of 1 μm or less without including a particle size of 10 μm or more. High polymer insulating material. 6. The polymer insulating material with high dielectric breakdown voltage according to claim 3, wherein the additive is organic polysilane, and the addition amount is 50 ppm by weight or more and 10% by weight or less. 7. The additive is maleic anhydride-grafted polypropylene, and the addition amount is 50 ppm by weight or more and 10 or more.
The polymer insulating material having a high breakdown voltage according to claim 3, which is not more than wt%. 8. The additive is a silane compound having an organic polyether group, and the addition amount is 50 ppm by weight or more and 1
The polymer insulating material having a high dielectric breakdown voltage according to claim 3, which is 0% by weight or less. 9. The polypropylene is selected from solid titanium catalyst components containing titanium, magnesium, halogen and an electron donating compound (internally added electron donating compound) and groups 1, 2 and 3 of the periodic table. The polymer insulating material according to claim 1, which is obtained by polymerizing propylene in the presence of a polymerization catalyst composed of an organometallic compound containing a metal and an electron donating compound (externally added electron donating compound). 10. The polymer insulating material according to claim 1, wherein polypropylene obtained by dehalogenating the polypropylene obtained by the polymerization method according to claim 9 is used. 11. The polymer according to claim 1, wherein the polypropylene obtained by the polymerization method according to claim 9 is washed with an inert hydrocarbon and then dehalogenated to obtain a polypropylene. Insulating material. 12. A polypropylene molded article having high electrical insulation, which is obtained by stretching the polymer insulating material according to claim 1 or 2 in at least one direction. 13. A polypropylene molded article having high electrical insulation, which is obtained by stretching the polymer insulating material according to any one of claims 3 to 8 in at least one direction. 14. An electrically insulating film obtained by biaxially stretching the polymer insulating material according to claim 1. Description: 15. An electrically insulating film having a thickness of 1 to 6 μm obtained by biaxially stretching the polymer insulating material according to any one of claims 1 to 8.