JPH0524106A - Heat-resistant insulating film - Google Patents

Abstract

PURPOSE:To obtain the above insulating film excellent in heat resistance and having industrial value by stretching a molded article obtained by the melt molding of a specific copolymer at least in one direction and treating the formed film with a solution containing a transition metal compound. CONSTITUTION:A copolymer consisting of propylene and vinyl silane is used and obtained by utilizing a catalyst consisting of TiCl3 and triethyl aluminum or various highly active catalysts imparting polyolefin. The copolymer is mixed with polypropylene or additives if necessary and molded into a sheet or film like shape in a molten state to be stretched uniaxially or biaxially. Subsequently, as a transition metal compound, a compound of group VIII, IX, X metal is utilized but a rhodium or platinum halide compound is especially pref. The stretched film is immersed in a solution containing said compound to be enhanced in heat resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene insulating film having excellent heat resistance. Specifically, it relates to a heat-resistant insulating film obtained by subjecting a film obtained from a particular copolymer to a particular treatment.

[0002]

2. Description of the Related Art Polypropylene films are used in many applications as insulating films for capacitors because they have relatively excellent mechanical properties and electrical characteristics.

[0003]

A problem with polypropylene films is that they are inferior in heat resistance due to the properties of the polymer, and it is conceivable that the polypropylene film may be crosslinked by various methods after being formed into a film (special Flat 3-33138),
There is a problem that the progress of cross-linking does not necessarily lead to the insulating properties at high temperatures.

[0004]

Means for Solving the Problems The inventors of the present invention have completed the present invention by solving the above problems and searching for a polypropylene film having excellent insulating properties at high temperatures.

That is, the present invention is a heat resistance obtained by treating a film obtained by melt-molding a copolymer of propylene and vinylsilane in at least one direction and treating the film with a solution containing a transition metal compound. It is an insulating film.

The insulating film of the present invention will be described in detail below by showing its manufacturing method.

In the present invention, the copolymer of alkenylsilane and propylene can be usually obtained by polymerizing propylene and alkenylsilane using a so-called Ziegler-Natta catalyst composed of a transition metal catalyst and an organometallic compound.
An example is disclosed in US Pat. No. 3,223,686.

In the present invention, an alkenylsilane having at least one Si—H bond is preferably used, and for example, a compound represented by the following general formula (Formula 1),

[0009]

Embedded image H ₂ C═CH— (CH ₂ ) _n —SiH _P R _3-P (wherein n is 0 to 12, p is 1 to 3 and R is a hydrocarbon residue having 1 to 12 carbon atoms). ) Can be exemplified, and specifically, vinyl silane,
Examples thereof include allylsilane, butenylsilane, pentenylsilane, and compounds in which H of some Si—H bonds of these monomers is replaced with chlorine.

In the present invention, it is also possible to use a copolymer obtained by copolymerizing a part of propylene with another olefin, and as the other olefin, ethylene, butene-1, pentene-1, hexene-1, 2 can be used. -Methylpentene, Heptene-
1, octene-1, etc. are exemplified, and those copolymerized so as to be less than 10 wt% of the total polymer can be used.

In the present invention, the copolymer of propylene and alkenylsilane is the TiCl ₃ copolymer described in the above-mentioned US patent.
It is also possible to use a catalyst composed of a triethylaluminum and triethylaluminum, but more preferably, various subsequently developed catalysts which give polyolefins with high activity are used.

As the polymerization method, in addition to the solvent method using an inert solvent, a bulk polymerization method or a gas phase polymerization method can be adopted.

As the catalyst composed of a transition metal compound and an organometallic compound, a titanium halide is preferably used as the transition metal compound and an organoaluminum compound is preferably used as the organometallic compound.

For example, titanium tetrachloride is used for metallic aluminum,
Titanium trichloride obtained by reduction with hydrogen or organoaluminum, modified with an electron donating compound, an organoaluminum compound, and optionally a catalyst system comprising an electron donating compound such as an oxygen-containing organic compound, or halogenation A catalyst comprising an electron-donating compound such as a transition metal compound catalyst obtained by supporting a titanium halide on a carrier such as magnesium or treated with an electron-donating compound and an organoaluminum compound, and optionally an oxygen-containing organic compound. System, or the reaction product of magnesium chloride and alcohol, is dissolved in a hydrocarbon solvent and then treated with a precipitating agent such as titanium tetrachloride to make it insoluble in the hydrocarbon solvent, and if necessary, electron donating properties such as ester and ether. Transition obtained by the method of treating with a compound of Group compound catalyst and an organoaluminum compound, the catalyst system and the like formed of an electron-donating compound such as oxygen-containing organic compound optionally (e.g., following various examples in the literature are described .Ziegler-Natta Cataly
sts and Polymerization by John Boor Jr (Academic Pr
ess), Journal of Macromorecular Science Reviews in
Macromolecular Chemistry and Physics, C24 (3) 355-38
5 (1984), C25 (1) 578-597 (1985)).

Alternatively, the polymerization can be carried out using a transition metal catalyst soluble in a hydrocarbon solvent and a catalyst composed of aluminoxane.

As the electron-donating compound, oxygen-containing compounds such as ethers, esters, orthoesters and alkoxysilicon compounds can be preferably exemplified, and alcohols, aldehydes, water and the like can also be used.

As the organoaluminum compound, trialkylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide and alkylaluminum dihalide can be used, and examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group and hexyl group. Examples of the halide include chlorine, bromine and iodine. Further, an aluminoxane which is an oligomer or polymer obtained by reacting the above organoaluminum with water or water of crystallization can also be used.

There is no particular restriction on the polymerization ratio of alkenylsilane and propylene, but when it is used in a mixture with polypropylene, alkenylsilane is usually 0.001
It is about 30 to 30 mol%, preferably 0.1 to 10 mol%. When used alone, it is about 0.0001 to 1 mol%.

The molecular weight of the polymer is not particularly limited, but when it is intended to improve the physical properties by mixing, it is preferable that the molecular weight is the same as or lower than the molecular weight of polypropylene used by mixing. Also, as a preferable molecular weight
The intrinsic viscosity measured with a tetralin solution at 135 ° C is 0.1 to 10
It is a degree.

In the present invention, as the polypropylene to be mixed with the above-mentioned copolymer, if necessary, in addition to a propylene homopolymer, a copolymer of less than 10 wt% of the above-mentioned other olefins can be used. The coalesced can also be obtained on the market.

In the present invention, various known additives such as stabilizers and fillers can be used in addition to polypropylene as the additive used by mixing with the copolymer of alkenylsilane and propylene.

In the present invention, a copolymer of alkenylsilane and propylene is mixed with polypropylene or an additive as required to form a composition prior to contact with the catalyst described later, and then melt-molded into a sheet or film. , Further stretched. There is no limitation on the conditions for producing this film, and uniaxially or biaxially stretched film is also used. Also, a film having a thickness of 1 to 300 μm is usually available.

In the present invention, as the transition metal compound, compounds of metals of groups 4 or 8 or 9 and 10 of the periodic table can be preferably used, and particularly, a halide of rhodium or platinum, or an alkoxy compound of titanium or zirconium. It can be preferably used.

The above-mentioned catalyst is generally used by dissolving it in the following solvent and diluting it, and immersing the above-mentioned film in the solution and heating it as necessary to obtain a heat-resistant film. You can As the solvent used, specifically, a hydrocarbon compound having 1 to 20 carbon atoms and a halogenated hydrocarbon compound can be used, and particularly, a halogenated hydrocarbon compound and an aromatic hydrocarbon compound are preferably used. Specifically, benzene, toluene, xylene, ethylbenzene, dichloromethane, chloroform, dichloroethane,
Examples include trichloroethane and perchloroethane.

In the present invention, the catalyst concentration is 0.0000.
It is carried out at about 01 to 1 g / liter, usually about 0.00001 to 0.1 g / liter.

In the present invention, the contact time is usually different depending on the conditions of contact, such as the concentration of the catalyst, the temperature of the catalyst solution, the shape of the copolymer, the concentration of alkenylsilane in the copolymer, etc. It is several minutes to several tens of hours. The temperature at the time of immersion is preferably a high temperature within the range where the stretched film is not deformed, from the viewpoint of the speed of the crosslinking reaction, but is usually room temperature to 200 ° C, preferably room temperature to 150 ° C. At this time, it is of course possible to stir to assist the dispersion of the catalyst.

The content of alkenylsilane in the preferable film depends on the content of alkenylsilane in the copolymer, but the proportion of the copolymer in the molded product is usually 0.1 wt% or more. It is preferred that the silane be present in an amount of 0.0001 wt% or more. From the viewpoint of moldability or reduction of the amount of expensive alkenylsilane used, 1.0 wt% or less is sufficient, and the alkenylsilane in the molded product is preferably about 0.0001 to 1.0 wt%.

[0028]

EXAMPLES The present invention will be further described with reference to the following examples.

Example 1 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. Under a nitrogen atmosphere, 300 g of magnesium chloride, 112 ml of diisobutyl phthalate and 60 ml of titanium tetrachloride were placed in each pot and pulverized for 40 hours. 300 g of the co-ground product thus obtained was placed in a 5 liter flask, 3 liters of toluene were added, and 110 ° C
After stirring for 30 minutes, the supernatant was removed. Toluene (3 liters) was added again, the mixture was stirred at 80 ° C. for 30 minutes, and the supernatant was removed. Then, the solid content was repeatedly washed with n-hexane to obtain a transition metal catalyst slurry. When a part of the sample was sampled and the titanium content was analyzed, the titanium content was 2.2 wt.
%Met.

In an autoclave having an internal volume of 5 liters, 40 ml of toluene, 100 mg of the above transition metal catalyst, 0.1 ml of dimethylcyclohexyldimethoxysilane and 0.20 ml of triethylaluminum were placed in a nitrogen atmosphere, 1.5 kg of propylene,
After adding 40g of vinyl silane and pressurizing 1N liter of hydrogen,
Polymerization was carried out at 75 ° C for 2 hours. After the polymerization, unreacted propylene was purged, the powder was taken out, filtered and dried to obtain 890 g of powder. The same reaction was repeated to obtain about 2.5 kg of polymer.

The intrinsic viscosity of this polymer measured with a tetralin solution at 135 ° C. was 1.68, and the melting point and the crystallization temperature were raised to the maximum peak temperature by raising or lowering the temperature at 10 ° C./min using a differential thermal analyzer. The melting point was 159 ° C and the crystallization temperature was 119 ° C. According to elemental analysis, the vinylsilane unit content was 1.1 wt%.

To 100 parts by weight of this polymer, 0.1 part by weight of a phenolic antioxidant and 0.1 part of calcium stearate are added.
After adding parts by weight and mixing with a Henschel mixer, the L / D
Pelletized at 240 ° C. using a 22 20 mmφ extruder. Using these pellets, a 700 μm thick sheet was obtained through a T-die at 240 ° C using a similar extruder, and further stretched (TM-
(Made by LOMG) and stretched 5 times in MD and 7 times in TD
A stretched film of 15 μm was obtained.

This stretched film was treated with 5 m of n-butyl titanate.
l in a solution of 1 liter of toluene at 80 ° C
Treated for 30 minutes. The physical properties of the treated film were measured as follows. Young's modulus (ASTM D882, Kg / m
m ² ) 228, tensile strength (ASTM D638, Kg / mm ² ) 18.5, dielectric breakdown voltage (ASTM D149, V / μ) 498 at 25 ° C, 484 at 80 ° C,
It was 435 at 120 ° C.

Comparative Example 1 Polymerization of Example 1 was carried out without using vinylsilane to obtain a propylene homopolymer (however, the amount of the catalyst used was
It was set to 15 mg. ). The procedure of Example 1 was repeated except that this polypropylene was used. Young's modulus was 220 and tensile strength was 1
5.0, dielectric breakdown voltage is 502 at 25 ℃, 414 at 120 ℃, 120 ℃
It was 392. Bad BDV at high temperature.

Comparative Example 2 The physical properties were measured as they were without contacting the catalyst in Example 1. Young's modulus was 227, tensile strength was 16.0, dielectric breakdown voltage was 505 at 25 ° C, 474 at 80 ° C, 415 at 120 ° C. Met.

Example 2 The same procedure as in Example 1 was carried out except that rhodium chloride triphenylphosphine complex was used instead of n-butyl titanate, Young's modulus was 223, tensile strength was 22.0, and breakdown voltage was
It was 498 at 25 ° C, 475 at 80 ° C, and 455 at 120 ° C.

[0037]

The insulating film of the present invention has excellent heat resistance and is industrially extremely valuable.

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[Procedure amendment]

[Submission date] August 16, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

That is, according to the present invention, a heat resistance obtained by treating a film obtained by melt-molding a copolymer of propylene and alkenylsilane in at least one direction with a film containing a transition metal compound is obtained. It is an insulating film.

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Claims (1)

Claims: 1. A film obtained by melt-molding a copolymer of propylene and vinyl silane and stretching the molded product in at least one direction is treated with a solution containing a transition metal compound. Heat resistant insulation film.