JP2009070780A - Insulating barrier of power switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating barrier of a power switch having incombustibility and anti-explosive stress property and excellent in tracking resistance and heat resistance. <P>SOLUTION: The power switch 1 includes a switching electrode 7 consisting of a fixed contact 2 and a movable contact 3. The three-phase switching electrode 7 is housed in a container surrounded by the insulating barriers 4 and 5 in a box-like form and an insulating barrier 6 is laminated on the outer side of the container. Each of the insulating barriers 4, 5, 6 is made of a polyamide resin composition prepared by compounding a triazine-based compound B of 3-14 pts.wt. with a polyamide resin A of 100 pts.wt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an insulating barrier for a power switch, and more particularly to an insulating barrier for a power switch that has flame resistance and is excellent in tracking resistance, explosion stress resistance, and heat resistance.

  Generally, in a power switch, three phases of switching electrodes (contacts) are installed adjacent to one metal container. When a contact that is energized under high voltage is opened, an arc discharge occurs between the opened contacts. Therefore, a barrier called an insulation barrier is installed between adjacent contacts to prevent arc contact between adjacent contacts. The Such an insulation barrier is used to ensure electrical insulation between the high voltage portion and the metal container (ground).

  Conventionally, sulfur hexafluoride gas has been enclosed in a metal container in order to eliminate arc discharge generated between the contacts when the contacts are opened. However, there has been a movement to suppress the use of sulfur hexafluoride gas due to environmental problems, and air switches using air as an insulating medium have been reviewed. However, when sulfur hexafluoride gas is not used, since the arc discharge generation time tends to be longer, the insulation barrier has higher resistance (difficulty) to high heat and high energy generated during arc discharge. It is required to have flammability, heat distortion resistance, etc. If the heat resistance is low, the insulation is lost due to the heat generated at the time of an internal short circuit, and if it is softened and deformed and straddles the electrodes between the phases, a re-short circuit will occur when power is retransmitted, making it a reliable power switch. This is to greatly impair the performance.

Conventionally, as a material constituting the insulating barrier, for example, an epoxy resin is often used as in Patent Document 1, for example. However, the epoxy resin has a problem that it lacks the arc resistance performance at the time of an internal short circuit of the specification required for a power switch and the strength (explosion stress resistance) that can withstand the generated impact. On the other hand, it is conceivable to form an insulation barrier using a flame retardant ABS resin having a high impact resistance, but the flame retardant ABS resin is required for the tracking resistance required for the performance of the insulation barrier of a power switch. And there was a problem that heat resistance was very low.
Japanese Patent Application Laid-Open No. 06-076703

  An object of the present invention is to provide an insulating barrier for a power switch having flame resistance and explosion stress resistance, and excellent tracking resistance and heat resistance.

  The insulation barrier of the power switch of the present invention is characterized by comprising a polyamide resin composition comprising 3 to 14 parts by weight of a triazine compound (B) per 100 parts by weight of the polyamide resin (A). To do.

  As the triazine compound (B), melamine cyanurate is preferably used. In addition, the shape of the insulating barrier of the power switch is preferably formed into a box shape.

  The power switch is configured by installing a switch electrode on the inner side surrounded by the insulating barrier.

  Since the insulating barrier of the power switch of the present invention is formed of a polyamide resin composition in which the triazine compound (B) is blended with the polyamide resin (A), it has excellent flame resistance and explosion stress resistance, Excellent tracking resistance and heat resistance. In addition, since it does not contain a halogen-based flame retardant, the load on the environment is small and an environment-friendly insulating barrier can be realized.

  Hereinafter, the present invention will be specifically described with reference to embodiments. In the present invention, “weight” means “mass”.

  FIG. 1 is a cross-sectional view showing an example of an insulating barrier of a power switch according to an embodiment of the present invention, where (A) is a cross-sectional view from the front and (B) is a cross-sectional view from the side.

  1A and 1B, a power switch 1 has an open / close electrode 7 composed of a three-phase fixed contact 2 and a movable contact 3, and each open / close electrode 7 is box-shaped by insulating barriers 4 and 5. It is comprised so that it may accommodate in the inside of the container enclosed by. An insulating barrier 6 is also laminated on the outside of the container.

  In the present invention, the shape of the insulation barrier is not limited to the illustrated example as long as the arc current generated in each phase is prevented from flowing to the adjacent phase and electrical insulation is ensured. In addition, there may be mentioned those in which each phase is separated by a plate-shaped molded product that is sufficiently larger than the electrode, and in which the electrode itself is sealed by a box-shaped molded product. In recent years, downsizing of a power switch has been demanded, and it is more preferable to make the insulating barrier in a box shape in order to meet the market needs for making the insulating barrier itself more compact. Also, make holes in the insulation barrier, make protrusions, or provide a grounding layer made of metal, etc., within the range where the arc when the contacts are opened is not in contact with each other and within the range where electrical insulation is ensured. You can also.

  The polyamide resin (A) used in the polyamide resin composition forming the insulating barrier of the present invention is a polyamide mainly composed of amino acid, lactam or diamine and dicarboxylic acid. Representative examples of the main constituents include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and paraaminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, and tetramethylenediamine. , Hexamethylenediamine, 1,5-pentanediamine, 2-methylpentamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylenediamine, paraxylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5 5-trimethylcyclohexa , Bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine, etc. , Cycloaliphatic, aromatic diamines, and adipic acid, peric acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid Examples include aliphatic, alicyclic and aromatic dicarboxylic acids such as acid, 5-sodium sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid and hexahydroisophthalic acid. Each of nylon homopolymers or copolymers derived from It can be used alone or in the form of mixtures.

  In the present invention, a particularly useful polyamide resin is a polyamide resin having a melting point of 150 ° C. or more and excellent in heat resistance and strength. Specific examples include polycaproamide (nylon 6), polyhexamethylene adipamide. (Nylon 66), polypentamethylene adipamide (nylon 56), polytetramethylene adipamide (nylon 46), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecane Amide (nylon 11), polydodecanamide (nylon 12), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6/66), polycaproamide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), poly Hexamethylene adipamide / poly Xamethylene isophthalamide copolymer (nylon 66 / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / polydodecanamide copolymer (nylon 6T / 12), polyhexa Methylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyxylylene adipamide (nylon XD6), polyhexamethylene terephthalamide / poly-2-methylpentamethylene Examples include terephthalamide copolymer (nylon 6T / M5T), polynomethylene terephthalamide (nylon 9T), and mixtures thereof. A particularly suitable example is nylon 66, which has an excellent balance between flame retardancy and explosion stress resistance.

  In the present invention, the degree of polymerization of the polyamide resin is not particularly limited, but the relative viscosity (98% sulfuric acid method) measured at 25 ° C. is 2.0 to 4.4 from the viewpoint of explosion stress resistance and heat resistance. The range of 5 is preferable, More preferably, it is 2.2-4.0, Most preferably, it is the range of 2.3-3.5.

  The triazine compound (B) used in the present invention is a compound containing a nitrogen element having a triazine skeleton, and is known as a flame retardant that can be added to a thermoplastic resin to impart flame retardancy. It is a compound. Specific examples include melamine, melem, melam, melon, and their salts with cyanuric acid, cyanuric acid, and mixtures thereof. A typical example of the salt is melamine cyanurate. As the triazine compound (B) used in the present invention, melamine cyanurate is particularly preferable from the viewpoint of heat resistance and good mixing with a polyamide resin.

  The polyamide resin composition forming the insulating barrier of the present invention has a configuration in which 3 to 14 parts by weight of the triazine compound (B) is blended with 100 parts by weight of the polyamide resin (A). By setting the blending amount of the triazine-based compound (B) within this range, a resin composition having flame retardancy, tracking resistance, and explosion stress resistance can be obtained. If it exceeds 14 parts by weight, the explosion stress resistance and strength of the polyamide resin composition are lowered. The lower limit of the amount of the triazine-based compound (B) is preferably 4 parts by weight, more preferably 5 parts by weight, and the upper limit of the amount is preferably 12 parts by weight, more preferably 10 parts by weight.

  The polyamide resin composition used in the present invention further includes other polymers, copper-based heat stabilizers, hindered phenol-based, phosphorus-based, sulfur-based antioxidants, heat stabilizers and the like as long as the object of the present invention is not impaired. One or more usual additives such as ultraviolet absorbers, lubricants, mold release agents, antistatic agents, flame retardants, and colorants including dyes and pigments can be added.

  The production method of the polyamide resin composition used in the present invention is not particularly limited, and examples thereof include a method of melt kneading at a temperature of 220 to 330 ° C. using a kneader such as a single or biaxial extruder or a kneader. .

  The insulating barrier of the present invention can be easily obtained by a usual method such as a molded product obtained by injection molding or extrusion molding using the above-described polyamide resin composition, or an adhesive assembly of parts obtained by those molding methods. The obtained insulation barrier has flame retardancy and is excellent in tracking resistance, explosion stress resistance and heat resistance.

  In particular, the insulating barrier of the present invention can retain its shape even if cracking occurs against explosion stress due to an internal short circuit that occurs when a switch breaks down. More preferably, the shape is maintained without cracking. If the insulating barrier is broken finely by explosive stress, there is a risk that fragments will fly out of the switch from the gap for internal pressure release generated when an internal short circuit occurs and cause a public disaster. Moreover, since the heat resistance is high, it is possible to prevent an accident that is softened by the heat generated at the time of an internal short circuit and straddles the electrodes between the phases.

  Moreover, since the insulation barrier of this invention has high tracking resistance, it improves the reliability of electric power supply as a component of a power switch. For example, according to the industrial standard JIS C 4605 of a power switch, plc0 is realized by a tracking resistance test compliant with UL746A.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited by these. Measurement methods used in Examples and Comparative Examples are shown below.

(1) Molding of Insulating Barrier Using an injection molding machine: KX360 manufactured by Kawaguchi Seiko Co., Ltd., an insulating barrier having the shape shown in FIG. 1 was injection molded at a cylinder temperature of 280 ° C. to obtain an insulating barrier molded product. The obtained insulation barrier was used for each characteristic test.

(2) Flame retardance A test piece having a size of 127 mm × 12.7 mm × 0.7 mm was cut out from the obtained insulating barrier and measured based on UL94.

(3) Tracking resistance A test piece having a size of 60 mm x 60 mm x 3 mm was cut out from the obtained insulating barrier, and measured by subjecting it to UL746A.

(4) Explosive stress resistance Contacts are placed inside the insulation barrier as shown in Fig. 1, enclosed in a metal container, and subjected to an arc resistance (internal accident) test of the switch based on JEM 1425 to break the insulation barrier. The condition was visually confirmed and used as an index of explosion resistance. Judgment criteria are as follows.
A: There is no destruction at all.
○: Although the surface is cracked, the original shape is retained.
Δ: Cracks occur on the surface, and the original shape is partially damaged.
×: Completely destroyed and does not retain the original shape

(5) Heat resistance A test piece having a size of 12.7 mm x 127 mm x 6 mm was cut out from the obtained insulating barrier, and subjected to ASTM D648 to measure the deflection temperature under load. The load was 0.46 MPa.

Example 1
As polyamide resin (A), polyamide 66 resin [manufactured by Toray Industries, Inc .: trade name CM3007] 100 parts by weight, (B) melamine cyanurate [manufactured by Nissan Chemical Industries, Ltd .: trade name MC440] 3.1 parts Using a twin screw extruder (manufactured by Toshiba Machine Co., Ltd .: TEM58), top feed (base feed) under conditions of a cylinder set temperature of 290 ° C. and a screw speed of 200 rpm, melt kneading, After forming and cooling with a cooling bath, it was granulated with a cutter to obtain pellets. Using the obtained pellets, an insulating barrier was formed by the above forming method, and various characteristics were examined by the above measuring method. The results are shown in Table 1.

Examples 2 and 3
Pellets were granulated in the same manner as in Example 1 except that the polyamide resins (A) and (B) melamine cyanurate were changed to the blending amounts shown in Table 1, and an insulating barrier was obtained to examine various properties. The results are shown in Table 1.

Comparative Examples 1 and 2
Pellets were granulated in the same manner as in Example 1 except that the polyamide resins (A) and (B) melamine cyanurate were changed to the blending amounts shown in Table 1, and an insulating barrier was obtained to examine various properties. The results are shown in Table 2.

Comparative Example 3
An insulating barrier was molded by the above molding method using a flame retardant ABS resin [manufactured by Toray Industries, Inc .: trade name 824V-X01], and various characteristics were examined by the above measuring method. The results are shown in Table 2.

Comparative Example 4
A flame-retardant epoxy resin [manufactured by Nagase ChemteX Corporation: trade name XNR4012 / XNH4012] is injected into a mold, heat-treated at 80 ° C. for 16 hours, and then heated at 120 ° C. for 21 hours. It hardened | cured, the insulation barrier was shape | molded, and various characteristics were investigated by the said measuring method. The results are shown in Table 2.

Comparative Example 5
(A) Polyamide 66 resin [manufactured by Toray Industries, Inc .: trade name CM3007] 100 parts by weight, brominated polystyrene [manufactured by Albemarle: trade name HP7010G] 30 parts by weight, antimony trioxide [manufactured by Nippon Seiko Co., Ltd .: [Product name PATOX-MK] 10 parts by weight are all top-fed (base feed) using a twin screw extruder (Toshiba Machine Co., Ltd .: TEM58) under the conditions of a cylinder set temperature of 290 ° C. and a screw rotation speed of 200 rpm. After kneading, a strand-like gut was formed, cooled with a cooling bath, and granulated with a cutter to obtain pellets. Using the obtained pellets, an insulating barrier was formed by the above forming method, and various characteristics were examined by the above measuring method. The results are shown in Table 2.

  From Examples 1-3 and Comparative Examples 1-5, by forming an insulation barrier with a resin composition obtained by blending polyamide 66 resin with melamine cyanurate at a specific ratio, flame retardancy, tracking resistance, explosion resistance It was confirmed that it was excellent in stress and heat resistance. Note that the insulating barrier of the present invention is an environment-friendly insulating barrier that does not contain a halogen-based flame retardant and therefore has a low environmental load.

An example of embodiment of the insulation barrier of the switch for electric power of the present invention is shown, (A) is a sectional view from the front, and (B) is a sectional view from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power switch 2 Fixed contact 3 Movable contact 4, 5, 6 Insulation barrier of power switch 7 Switch electrode

Claims (4)

  An insulating barrier for a power switch comprising a polyamide resin composition comprising 3 to 14 parts by weight of a triazine compound (B) per 100 parts by weight of a polyamide resin (A).   The insulation barrier for a power switch according to claim 1, wherein the triazine compound (B) is melamine cyanurate.   The insulation barrier for a power switch according to claim 1 or 2, wherein the shape is formed in a box shape.   A power switch comprising an open / close electrode disposed inside the insulating barrier according to claim 1, 2 or 3.

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