JP3100427B2 - Heat resistant insulation film - Google Patents

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. More specifically, the present invention relates to a heat-resistant insulating film obtained by performing a specific treatment on a film obtained from a specific copolymer.

[0002]

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

[0003]

The problem of the polypropylene film is that it is inferior in heat resistance due to the properties of the polymer, and it is conceivable that after being formed into a film, it is crosslinked by various methods. Hei 3-33138),
There has been a problem that the progress of cross-linking does not necessarily lead to insulation properties at high temperatures.

[0004]

Means for Solving the Problems The present inventors have solved the above-mentioned problems and have intensively searched for a polypropylene film having excellent insulating properties at high temperatures and completed the present invention.

That is, the present invention provides a heat-resistant film obtained by subjecting a film obtained by melt-molding a copolymer of propylene and alkenylsilane to at least one direction and treating the film with a solution containing a transition metal compound. This is a conductive 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 generally obtained by polymerizing propylene and alkenylsilane using a so-called Ziegler-Natta catalyst comprising a transition metal catalyst and an organometallic compound.
An example is disclosed in U.S. Pat. No. 3,223,686.

In the present invention, alkenyl silanes having at least one Si—H bond are preferably used, for example, a compound represented by the following general formula (Chemical Formula 1):

[0009]

Embedded image H ₂ C = CH— (CH ₂ ) _n —SiH _P R _3-P (where 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, specifically, vinyl silane,
Examples thereof include allylsilane, butenylsilane, pentenylsilane, and compounds in which H of Si—H bond in some of these monomers is substituted with chloro.

In the present invention, a copolymer obtained by copolymerizing a part of propylene with another olefin may be used. Other olefins include ethylene, butene-1, pentene-1, hexene-1,2 -Methylpentene, heptene-
1, octene-1 and the like, and those copolymerized so as to be less than 10% by weight of the whole polymer can be used.

[0011] In the present invention, the copolymer of propylene and alkenylsilane may be a TiCl ₃
Although a catalyst comprising triethylaluminum and triethylaluminum can be used, more preferably, various catalysts which have been developed thereafter and provide a polyolefin with high activity are used.

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

As the catalyst comprising the transition metal compound and the 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 converted to metallic aluminum,
A catalyst system comprising titanium trichloride obtained by reduction with hydrogen or organoaluminum, modified with an electron-donating compound, an organoaluminum compound, and, if necessary, an electron-donating compound such as an oxygen-containing organic compound, or a halogenated compound. A catalyst comprising a transition metal compound catalyst obtained by supporting titanium halide on a carrier such as magnesium or those obtained by treating them with an electron donating compound and an organoaluminum compound and, if necessary, an oxygen-containing organic compound. The system, or the reaction product of magnesium chloride and alcohol, is dissolved in a hydrocarbon solvent, and then treated with a precipitant such as titanium tetrachloride to make it insoluble in the hydrocarbon solvent. Transition obtained by treating with a compound of formula (1) and then treating with a titanium halide 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) and C25 (1) 578-597 (1985)).

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

Here, as the electron-donating compound, oxygen-containing compounds such as ether, ester, orthoester and alkoxysilicon compound can be preferably exemplified, and alcohol, aldehyde, water and the like can be used.

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

Here, the polymerization ratio of the alkenylsilane and propylene is not particularly limited.
About 30 mol%, preferably 0.1 to 10 mol%. When used alone, the content is about 0.0001 to 1 mol%.

The molecular weight of the polymer is not particularly limited, but when it is desired to improve the physical properties by mixing, the molecular weight is preferably about the same as or less than the molecular weight of the polypropylene used by mixing. As a preferable molecular weight,
Intrinsic viscosity of 0.1 to 10 measured in 135 ° C tetralin solution
It is about dl / g .

In the present invention, as the polypropylene to be used as a mixture with the above copolymer, if necessary, in addition to a homopolymer of propylene, those obtained by copolymerizing the other olefins of less than 10% by weight can be used. Coalescence can also be obtained on the market.

In the present invention, known additives such as stabilizers and fillers can be used in addition to polypropylene as additives to be mixed with the alkenylsilane / propylene copolymer.

In the present invention, the alkenylsilane-propylene copolymer is mixed with polypropylene or additives as necessary to form a composition before contacting with a catalyst described below, and then melt-formed into a sheet or film. And further stretched. The conditions for producing this film are not limited, and the film is stretched uniaxially or biaxially. A film having a thickness of usually 1 to 300 μm can be used.

In the present invention, as the transition metal compound, a compound of a metal belonging to Group 4 or 8, or 9 or 10 of the periodic table can be preferably used. In particular, a halide of rhodium or platinum, or an alkoxy compound of titanium or zirconium can be used. It can be used preferably.

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

In the present invention, the concentration of the catalyst 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 preferred contact time varies depending on the conditions at the time of contact, for example, the concentration of the catalyst, the temperature of the catalyst solution, the shape of the copolymer, the concentration of the alkenylsilane in the copolymer, and the like. A few minutes to a few tens of hours. The temperature for immersion is preferably a high temperature in the range that the stretched film is not deformed, in view of the speed of the crosslinking reaction, but is usually from normal temperature to 200 ° C, preferably from normal temperature to 150 ° C. At this time, it is of course possible to stir to assist dispersion of the catalyst.

The preferred alkenylsilane content in the film depends on the alkenylsilane content in the copolymer, but the proportion of the copolymer in the molded product is usually 0.1% by weight or more, and the alkenylsilane in the molded product is usually 0.1 wt% or more. It is preferred that the silane be present at 0.0001 wt% or more. Further, from the viewpoint of moldability or reducing the amount of expensive alkenylsilane used, 1.0 wt% or less is sufficient, and preferably about 0.0001 to 1.0 wt% as alkenylsilane in the molded product.

[0028]

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

Example 1 A vibration mill equipped with four grinding pots having a capacity of 4 liters and containing 9 kg of steel balls having a diameter of 12 mm was prepared. 300 g of magnesium chloride, 112 ml of diisobutyl phthalate and 60 ml of titanium tetrachloride were put in each pot under a nitrogen atmosphere, and pulverized for 40 hours. 300 g of the co-ground product thus obtained was placed in a 5-liter flask, and 3 liters of toluene were added.
For 30 minutes, and then the supernatant was removed. Again, 3 liters of toluene was added, and the mixture was stirred at 80 ° C. for 30 minutes, and then the supernatant was removed. Thereafter, the solid content was repeatedly washed with n-hexane to obtain a transition metal catalyst slurry. A part of the sample was analyzed for titanium content.
%Met.

In a 5 liter autoclave, under a nitrogen atmosphere, 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, and 1.5 kg of propylene was added.
After adding 40 g of vinyl silane and pressing in 1N liter of hydrogen,
Polymerization was performed at 75 ° C. for 2 hours. After the polymerization, unreacted propylene was purged, the powder was taken out and filtered and dried to obtain 890 g of powder. The same reaction was repeated to obtain about 2.5 kg of a polymer.

The intrinsic viscosity of this polymer measured in a 135 ° C. tetralin solution was 1.68 dl / g , and the melting point and crystallization temperature were raised or lowered at 10 ° C./min using a differential thermal analyzer. When measured as the maximum peak temperature, the melting point was 159 ° C and the crystallization temperature was 119 ° C. According to elemental analysis, it contained 1.1 wt% of a vinylsilane unit.

To 100 parts by weight of this polymer, 0.1 part by weight of a phenolic antioxidant, 0.1 part of calcium stearate
After adding parts by weight and mixing with a Henschel mixer, L / D
Pellets were formed at 240 ° C. using a 22 × 20 mm extruder. Using the pellets, a similar extruder was used to obtain a 700 μm thick sheet through a T-die at 240 ° C.
Stretched 5 times in MD direction and 7 times in TD direction
A 15 μm stretched film was obtained.

This stretched film was treated with n-butyl titanate 5 m
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 and were as follows. Young's modulus (ASTM D882, Kg / m
m ² ) 228, tensile strength (ASTM D638, Kg / mm ² ) 18.5, breakdown voltage (ASTM D149, V / μ) 498 at 25 ° C, 484 at 80 ° C,
It was 435 at 120 ° C.

Comparative Example 1 The polymerization of Example 1 was carried out without using vinylsilane to obtain a propylene homopolymer (provided that the amount of catalyst used was
It was 15 mg. ). Except for using this polypropylene, the same procedures as in Example 1 were carried out to find that the Young's modulus was 220 and the tensile strength was 1
5.0, breakdown voltage 502 at 25 ° C, 414 at 80 ° C, 120 ° C
Was 392. Bad BDV at high temperature.

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

Example 2 The procedure of Example 1 was repeated, except that the triphenylphosphine complex of rhodium chloride was used instead of n-butyl titanate. The Young's modulus was 223, the tensile strength was 22.0, and the dielectric 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 extremely valuable industrially.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // B29L 7:00 (56) References JP-A-4-248842 (JP, A) JP-A 4-239527 (JP, A JP-A-2-138308 (JP, A) JP-A-2-120301 (JP, A) JP-A-1-287139 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 7/00-7/18 C08J 5/18 B29C 55/00-55/30 B29C 71/00-71/04 C08F 210/06

Claims (1)

(57) [Claims] 1. A heat-resistant insulating film obtained by subjecting a film obtained by melt-molding a copolymer of propylene and alkenylsilane to at least one direction and treating the film with a solution containing a transition metal compound. .