JP3469315B2 - Electrical insulation material - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] Field of the Invention The present invention relates to an electrical insulating member using the electrical insulating materials. More particularly, this formed by using the including electrical insulating material syndiotactic polypropylene
And an electrical insulating member. BACKGROUND OF THE INVENTION Isotactic polypropylene (hereinafter, also referred to as "i-PP") which has been conventionally used as an electrical insulating material is inherently rigid, In addition to being limited to electrical insulation as a bulk material, it is often unsuitable in terms of rigidity and brittleness (prone to cracking) even in the form of a thin sheet or a composite with other materials. Was a drawback. [0003] Other general-purpose electrical insulating materials used include:
Examples include low-density polyethylene (LDPE) and ethylene propylene rubber (EP rubber), and an electrical insulating material having higher electrical properties and physical properties, and an electrical insulating member using the same have been demanded. [0004] The present inventors examined the applicability of various materials to electrical insulating materials, and found that syndiotactic polypropylene (hereinafter referred to as "s-t-polypropylene").
PP)), but the conventional general-purpose electrical insulating material L
It has higher electrical properties than DPE and EP rubber, and i
-Excellent in crack retention and other properties retention after molding (e.g., little change in electrical and mechanical properties due to quenching after molding). It has been found that it also has great flexibility. That is, according to the present invention, the syndiotactic pentad fraction is 0.7 or more and the MFR is 0.1 to 2
The 0 g / 10 min range syndiotactic polypropylene of about electrical insulating member characterized by comprising using including electrical insulating material. [0006] The s-PP used in the present invention is a concept including not only a homopolymer of polypropylene having a syndiotactic structure but also a copolymer of propylene and other olefins. , S-PP including the copolymer. In the present invention, s-PP, which is a homopolymer, is preferred. [0007] The preferred molecular weight of the s-PP used in the present invention is from 3,000 to 400,000, more preferably from 10,000 to 200,000. The s-PP used in the present invention must have a syndiotactic pentad fraction of 0.7 or more. Here, the syndiotactic pentad fraction is defined as 20.2 based on tetramethylsilane in a 13C-NMR spectrum measured at 67.8 MHz in a 1,2,4-trichlorobenzene solution at 135 ° C.
The peak intensity observed in ppm (peak intensity of the methyl group attributed to the syndiotactic pentad chain) refers to the ratio of the peak intensity attributed to all the methyl groups of the propylene unit. Syndiotactic pentad fraction of 0.7
Since the s-PP of less than 10% has a low melting point and lowers the electrical breakdown strength and mechanical properties, it should not be used as a material for the electrical insulating member of the present invention. The syndiotactic pentad fraction is preferably 0.8 to 0.8 from the viewpoint of electric field resistance.
0.95, more preferably 0.86 to
0.95. Further, the s-PP is ASTM-D-1.
The melt flow rate (MFR) (load: 10 kgf, temperature: 230 ° C.) specified in 238 is 0.1 to 20 g.
It is necessary to have a range of / 10 minutes. 20g / 10
S-PP having an MFR of more than 0.1 min has too high a fluidity at high temperature, and conversely, an MFR of less than 0.1 g / 10 min.
The fluidity of s-PP having the following is too small. Therefore, when any of the s-PP is used as the material of the electrical insulating member of the present invention, there is a problem in workability. The preferred range of the MFR is 0.3 to 15 g / 10 minutes from the viewpoint of high temperature fluidity.
A more preferred range is 0.5 to 10 g / 10 minutes from the viewpoint of extrusion processability and moldability. [0010] The method for producing the s-PP is not particularly limited. That is, as the polymerization catalyst to be used, an organometallic complex catalyst having a symmetric or asymmetric molecular structure, for example, a stereospecific polymerization catalyst such as a metallocene compound or the like can be used. The polymerization conditions are not particularly limited. For example, they can be produced by a bulk polymerization method, a gas phase polymerization method, a solution polymerization method using an inert solvent, or the like. The s-PP may contain, if necessary, an antioxidant or stabilizer such as a hindered phenol type, an amine type or a thioether type, a copper damage inhibitor such as an amide or hydrazide type, a benzophenone type or a benzoin type. Usually used for plastics, such as UV-blocking agents, lubricants such as higher fatty acids or their metal salts, processing aids, organic and inorganic pigments, organic and inorganic flame retardants, and fillers such as silica and clay. May be added. The impulse breakdown electric field strength at room temperature of the s-PP used in the present invention is 10 to 25% than that of the conventional low-density polyethylene (LDPE), and 11 compared with the i-PP.
0 to 140%, and the AC breakdown electric field strength at room temperature is L
2.5-8.5% more than DPE, 1 more than crosslinked LDPE
4-20%, 45-55% higher than i-PP. Such s-PP and including electrical insulating materials, electrical properties (AC breakdown characteristics, impulse breakdown characteristics, volume resistivity, dielectric constant), after which is particularly excellent in electromigration fracture properties, sufficient for electrical insulation member It has flexibility that can be used. Further, when manufacturing an electrical insulating member from a material containing the s-PP,
Even if the material is melt-molded and then gradually cooled (−10 ° C./min) or rapidly cooled in ice water at 0 ° C., the obtained electrical insulating member maintains excellent electrical properties. Further, the s-PP used in the present invention is excellent in workability and has a higher breaking point strength than high-density polyethylene (HDPE), which is one of the conventional materials for electrical insulating members. In particular, when the material used in the present invention is quenched after being melted, the obtained member is superior in terms of breaking strength and retention of elongation characteristics as compared with those using HDPE. That is, when the electrical insulating material used for the electrical insulating member of the present invention is formed by extrusion, injection molding, or other methods, it can be rapidly cooled while maintaining excellent characteristics, and can be processed at a high speed. To increase the production efficiency. The electrically insulating member according to the present invention includes, in addition to an electrically insulating paper made of paper mixed with cellulose and an oil-immersed insulator obtained by combining the same with an insulating oil, tape, sheet, spacer, plug, socket, pipe, Examples include insulating rods, various electrical molded products, circuit components, and sealing materials. Each of these members is formed by a known method. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. EXAMPLES Example 1 Syndiotactic Pentad Fraction of 0.80 to 0.9
5, various syndiotactic polypropylenes shown in Table 1 were continuously extruded at 180 ° C. using a 50 mmφ extruder equipped with a T-die to obtain a 1 mm thick tape. In order to compare the various performances of the obtained tape, the tape was melt-molded at 180 ° C. using a compression molding machine (5 minutes), and then gradually cooled (room temperature standing cooling) or quenched in 0 ° C. ice water. Into a 0.3 mm thick sheet. Each sample was subjected to an impulse breakdown test, an AC breakdown test, and a physical property test using an improved McKeown electrode system.
In the impulse breakdown test, a negative impulse standard wave of 1 × 40 μsec was applied by a step-up boosting method of applying 1 kV / 3 times with 70% of an expected breakdown voltage as an initial value. It should be noted that both the impulse breakdown test and the AC breakdown test
Data of 10 samples were collected under the conditions, and after Weibull analysis, the breakdown value at a probability of failure of 63.3% was taken as the withstand pressure value of the sample. The physical property test was conducted according to JIS K
7113, using a Tensilon tensile tester. Table 1 shows the electrical breakdown characteristics at room temperature, and Table 2 shows the mechanical characteristics. Comparative Example 1 For comparison, the syndiotactic pentad fraction was 0.6
For s-PP, conventional i-PP, and high-pressure LDPE, samples were prepared in the same manner as in Example 1, and electrical and mechanical properties were evaluated. The results are shown in Tables 1 and 2. [Table 1] [Table 2] As shown in Tables 1 and 2, the present invention is used.
The electrical insulating tape manufactured from the used electrical insulating material maintained good electrical breakdown characteristics and mechanical characteristics even after being gradually cooled or rapidly cooled at 0 ° C. after being processed into a sheet shape. The electrical insulation of the present invention using a specific s-PP
The electrical insulation material used for the edge member has excellent electrical properties,
Particularly, when the member made of the insulating material was processed again, excellent electrical characteristics and mechanical characteristics were maintained regardless of whether the material was rapidly cooled or gradually cooled. That is,
The electric insulating material used for the electric insulating member of the present invention has excellent electric characteristics and can provide a member having strong material strength. There is an advantage that mechanical properties can be maintained.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobutaka Uchikawa 3-5-2 Kasumigaseki, Chiyoda-ku, Tokyo Mitsui Toatsu Chemicals Co., Ltd. (72) Inventor Katsumi Yoshino 166-3 Oomachi, Kishiwada-shi, Osaka ( 56) References JP-A-5-163394 (JP, A) JP-A-2-195604 (JP, A) JP-A-63-146949 (JP, A) JP-A-61-23634 (JP, A) 1975-33140 (JP, B1) JP 50-5224 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 3/44 C08L 23/10

Claims (1)

(57) Claims 1. The syndiotactic pentad fraction is 0.7 or more, and the MFR is 0.1 to 20 g / 10.
Electrically insulating portion, characterized by comprising using a syndiotactic polypropylene minute range including photoelectric <br/> gas insulating material
Wood .