DE102007055667B4 - Arc quenching resin molding and use of an arc extinguishing resin molding in a circuit breaker - Google Patents

Abstract

An arc extinguishing resin molded article comprising a resin composition, said resin composition containing: a polyolefin resin (A) in which a part of hydrogen atoms in a methylene chain is replaced by hydroxyl groups and hydroxyl groups in an amount ranging from 0.2 to 0.7 mol, based on 1 mole of the methylene groups are included; A reactive organic phosphorus-based flame retardant (B) containing at least one of the groups -CH = CH 2 or -C (CH 3) = CH 2 d. H. contains an unsaturated end bond; and a polyacetal resin (C) in an amount in the range of 5 to 90 parts by weight based on 100 parts by weight of the polyolefin resin (A), wherein the polyacetal resin (C) has structural units derived from oxymethylene in one Content in the range of 75 to 100 mol%, and the polyacetal resin (C) is dispersed in the polyolefin resin (A) to form a microphase separation structure; wherein the resin composition after forming into the resin molded body was subjected to irradiation by α-ray, γ-ray, X-ray or ultraviolet ray for crosslinking.

Description

Technical field of the invention

The present invention relates to an arc extinguishing resin molded article having flame retardant properties, which is used for extinguishing an electric arc resulting from contact parts in the case of power interruption in a circuit breaker or the like, and a use of such an arc extinguishing resin molded article in a circuit breaker according to the claims ,

Background of the invention

An electric arc occurs between a contact piece of a movable contact portion and a contact piece of a fixed contact portion of a circuit breaker when the contacts are opened with flowing overcurrent or rated current. In order to extinguish the arc, there is generally provided a circuit breaker having an arc-extinguishing member having an arc chamber consisting of an arc-extinguishing member around the arc-generating site. The arc-extinguishing element is thermally decomposed by the arc, and the gas generated by the thermal decomposition of the arc-extinguishing element extinguishes the arc.

Mainly used matrix resins of the arc-extinguishing element include thermosetting resins such as unsaturated polyester resins (Patent Document 1) and melamine resins (Patent Document 2) and thermoplastic resins such as polyolefin resins, polyamide resins and polyacetal resins (Patent Document 3).

However, thermosetting resins have a problem in that their molding properties are inferior to those of thermoplastic resins because the thermosetting resin tends to form flash in the molding process. In the arc extinguishing process, the gas generated by thermal decomposition from the arc extinguishing element increases the pressure in the arc extinguishing device. The thermosetting resin, which has a low compressive strength and easily breaks while having a relatively high hardness, is hardly suitable for miniaturizing the arc extinguishing device.

On the other hand, thermoplastic resins, which are hardly burred, have lower strength, lower pressure resistance, and lower heat resistance, so that the arc extinguishing element tends to be deformed or decomposed over time. A thermoplastic resin containing numerous aromatic rings, such as an aromatic polyamide resin, has relatively high strength, high pressure resistance, and high heat resistance, but readily gives off free carbon upon combustion. As a result, the arc extinguishing component can be contaminated by carbon and impaired in electrical insulation.

For improving the strength, pressure resistance and heat resistance of the thermoplastic resins and the thermosetting resins, some attempts have been made (Patent Documents 1 to 4) containing an inorganic filler material such as reinforcing fibers in the resin. However, by increasing the content of inorganic fillers, the amount of gas generated by thermal decomposition decreases, resulting in a problem that the arc extinction behavior is impaired.

Patent Document 5 describes a circuit breaker using a resin molded article obtained by electron irradiation of thermoplastic resins such as polyesters and polyamides.

Recently, higher demands are placed on the degree of flame retardancy required of resin materials used in circuit breakers. To meet these requirements, the use of a flame-retardant resin as a matrix resin of an arc-quenching material is conceivable. It is known that a compound containing a halogen such as bromine is effective in a resin for flame retardancy. Resins containing halogen compound-type additives are used for general-purpose flame retardant resins. However, a flame retardant resin containing a large amount of a halogen compound may produce dioxin under certain combustion conditions. In view of the burden on the environment, the use of a halogen-free flame retardant resin containing no halogen compound has been required for several years.

Patent Document 1

• Japanese Patent 3098042 and related patent publications in other countries: U.S. Patent 6,046,258 . DE patent 69717433 and European Patent 0 897 955 ,

Patent Document 2

• Japanese Laid-Open Patent H02-256110 ,

Patent Document 3

• Japanese Laid-Open Patent H07-302535 and related patent publications in other countries: U.S. Patent 5,841,088 . EP-A-0 694 940 and CN-1 124 402 ,

Patent Document 4

• Japanese Laid-Open Patent H08-171847 and related patent publications in other countries: U.S. Patent 6,361,848 . DE patent 69532063 . European Patent 0 718 356 and CN patent 1 169 866 ,

Patent Document 5

• The international patent application WO-2003-044818 and related patent publications in other countries: EP-A-1 475 817 and CN Patent 1 255 839 ,
• EP 1 659 148 A1 describes, among many others, organic phosphorus-based, flame retardant crosslinkable agents. These can be z. B. include many other thermoplastic resins and polyolefin-based resins.
• EP 1 555 283 A1 describes resin moldings containing organic, flame retardant, crosslinkable phosphorus compounds.

Disclosure of the invention

Problems to be solved by the invention

Although crosslinking treatment of a thermoplastic resin shows some improvement in strength, heat resistance and pressure resistance, arc extinguishing performance does not improve. Further, the pressure increase in the arc-extinguishing member is hardly suppressed in the extinguishing operation due to the gas generated by thermal decomposition, and the arc-extinguishing member is easily broken due to the pressure increase in the arc extinguishing operation. Furthermore, the flame-retardant nature is still one of the unsolved problems.

It is therefore an object of the present invention to provide an arc extinguishing resin molded body which generates a thermal decomposition gas at a small pressure rise and with high extinction efficiency of an electric arc generated at the time of turn-off, the molded body against the temperature rise and pressure rise occurring at the turn-off operation Resistant and has a good flame retardant nature. Another object is to provide use of an arc quench resin molding in a circuit breaker.

Solution of the tasks

In order to achieve the above objects, an arc extinguishing resin molded article according to claim 1 and a use of an arc extinguishing resin molded article according to claim 7 are proposed. Dependent claims relate to preferred embodiments of the invention.

An arc extinguishing resin molded article according to the present invention comprises a resin composition containing a polyolefin resin (A) in which a part of hydrogen atoms in a methylene chain passes through Hydroxyl groups is replaced and the hydroxyl groups in an amount ranging from 0.2 to 0.7 mol, based on 1 mol of methylene groups, wherein the resin composition further contains a reactive, organic flame retardant phosphorus-based (B), the at least one of the groups -CH = CH ₂ or -C (CH ₃ ) = CH ₂ ie having an unsaturated end bond. Further, the resin composition contains a polyacetal resin (C) in an amount ranging from 5 to 90 parts by weight based on 100 parts by weight of the polyolefin resin (A), wherein the polyacetal resin (C) is derived from oxymethylene structural units. in a proportion ranging from 75 to 100 mol%, and the polyacetal resin (C) is dispersed in the polyolefin resin (A) to form a microphase separation structure. In addition, after a molding operation, the resin composition was subjected to irradiation by α-ray, γ-ray, X-ray or ultraviolet ray for crosslinking in the resin molded article of the present invention.

In the arc extinguishing resin molded body described above, crosslinks are formed in a three-dimensional mesh configuration by chemical reaction between the unsaturated end bonds of the phosphorus-based reactive organic flame retardant (B) and the polyolefin resin (A) with the aid of irradiation. As a result, the flame-retardant components are stably incorporated in the resin. Therefore, bleeding of the flame retardant hardly occurs, and the flame retardancy can be maintained for a long period of time. Since the crosslinks in the three-dimensional mesh configuration are formed in the polyolefin resin (A), the strength, heat resistance and pressure resistance are also improved.

The polyolefin resin (A) having a side-chain OH group which is susceptible to dissociation by pyrolysis generates a thermal decomposition gas containing hydrogen gas, H ₂ O, O ₂ and O in a high concentration, thus extinguishing the arc immediately. The polyolefin resin (A), which contains components such as tars that contribute little to the arc extinguishing function in low concentration, controls the pressure increase in the arc extinguishing device. Furthermore, it hardly comes in the process of arc extinction to stick the components in the arc extinguishing component. Therefore, the electrical insulation in the arc extinguishing component is ensured.

Although a polyacetal resin generally generates a thermal decomposition gas which is very effective in terms of arc extinction, there are difficulties in forming by melt-kneading, that is, molding. H. it has a poor shaping behavior. Since a polyacetal resin generates ample amounts of thermal decomposition gas, which gives a relatively large contribution to the pressure increase, the pressure in the arc extinguishing device tends to increase. However, according to the invention, the polyolefin resin (A) is used in combination with a polyacetal resin (C) so that the arc extinguishing performance is improved without impairing the molding properties of the resin composition.

Further, in the resin composition of the arc extinguishing resin molded body of the present invention, the polyacetal resin (C) is dispersed in the polyolefin resin (A) to form a microphase separation structure. According to this aspect of the invention, the polyacetal resin (C) readily undergoes pyrolysis and emits a thermal decomposition gas which exhibits high-quality arc extinguishing performance in the thermal decomposition process of the arc extinguishing resin molded body. Therefore, the arc is extinguished immediately.

Preferably, the resin composition contains one or more types of inorganic filler (D) selected from the group consisting of glass fibers, barium titanate whiskers, silica fine particles, boehmite, talc, magnesium carbonate and a metal hydroxide in an amount of 1 to 70% by weight. According to this aspect of the invention, the strength and the pressure resistance of the resin molded article are increased.

Preferably, the polyolefin resin (A) has a latent heat of decomposition of at least 125.6 J / g (30 cal / g).

Preferably, the polyolefin resin (A) is an ethylene-vinyl alcohol copolymer.

In accordance with these aspects of the invention, a thermal decomposition gas having excellent arc extinction capability for instantaneous arc extinction is produced. Thus, the arc voltage is maintained.

wobei die Reste R¹ bis R⁴ jeweils die Bedeutung CH₂=CY¹-Y²- haben oder eine monofunktionelle aromatische Kohlenwasserstoffgruppe, die ein Heteroatom enthalten kann, bedeuten und R⁵ eine difunktionelle aromatische Kohlenwasserstoffgruppe, die ein Heteroatom enthalten kann, bedeutet, die Reste X¹ bis X⁴ jeweils eine Gruppe bedeuten, die aus -O-, -NH-, - (CH₂=CY¹-Y²)N- ausgewählt ist und mindestens eine der Reste X¹ bis X⁴ die Gruppe -NH- oder die Gruppe -(CH₂=CY¹-Y²)N- enthält;
mindestens einer der Reste R¹ bis R⁴ und der Reste X¹ bis X⁴ die Gruppe CH₂=CY¹-Y²- enthält;
Y¹ ein Wasserstoffatom oder eine Methylgruppe bedeutet; und
Y² eine Alkylengruppe mit 1 bis 5 Kohlenstoffatomen oder -COO-Y³- bedeutet, wobei Y³ eine Alkylengruppe mit 1 bis 5 Kohlenstoffatomen bedeutet. Chemische Formel 2

wobei in einem Molekül mindestens eine P-C-Bindung enthalten ist;
die Reste Ar¹ und Ar² jeweils eine difunktionelle aromatische Kohlenwasserstoffgruppe mit höchstens 20 Kohlenstoffatomen bedeuten, die kein mobiles Wasserstoffatom enthält, und n eine ganze Zahl mit einem Wert von 0, 1 oder 2 ist; die Reste R⁶ bis R¹⁰ jeweils eine Gruppe bedeuten, die aus -NHCH₂CH=CH_{2 ,} -N(CH₂CH=CH₂)₂, -OCH₂CH=CH₂, -CH₂CH=CH₂, -CH₂CH₂OCH=CH₂, -(C₆H₄)-CH=CH₂, -O(C₆H₄)-CH=CH₂, -CH₂(C₆H₄)-CH=CH₂, -NH(C₆H₄)-CH=CH₂, -N(CH₂CH=CH₂)-(C₆H₄)-CH=CH₂, -O-R-OOC-C(R')=CH₂, -NH-R-NHCO-C(R')=CH₂ und einer Arylgruppe mit höchstens 12 Kohlenstoffatomen ausgewählt ist, wobei R eine Alkylengruppe mit 2 bis 5 Kohlenstoffatomen bedeutet und R' ein Wasserstoffatom oder eine Methylgruppe bedeutet;
mindestens eine der Reste R⁶ bis R¹⁰ eine -CH=CH₂-Gruppe oder eine -C(CH₃)=CH₂-Gruppe enthält. Preferably, the phosphorus-based reactive organic flame retardants (B) are an organic phosphorus compound of the formula (I) and / or the formula (II) wherein the agents are present in the resin composition in an amount ranging from 0.5 to 20 wt .-% are included. Chemical formula 1

where R ¹ to R ⁴ each have the meaning CH ₂ = CY ¹ -Y ² - or a monofunctional aromatic hydrocarbon group which may contain a heteroatom, and R ⁵ denotes a difunctional aromatic hydrocarbon group which may contain a heteroatom, the radicals X ¹ to X ⁴ each represent a group which is selected from -O-, -NH-, - (CH ₂ = CY ¹ -Y ² ) N- and at least one of the radicals X ¹ to X ^{4 is} the group NH- or the group - (CH ₂ = CY ¹ -Y ² ) N-;
at least one of the radicals R ¹ to R ⁴ and the radicals X ¹ to X ^{4 contains} the group CH ₂ = CY ¹ -Y ² -;
Y ^{1 represents} a hydrogen atom or a methyl group; and
Y ^{2 represents} an alkylene group having 1 to 5 carbon atoms or -COO-Y ³ -, wherein Y ^{3 represents} an alkylene group having 1 to 5 carbon atoms. Chemical formula 2

wherein at least one PC bond is contained in a molecule;
the radicals Ar ¹ and Ar ² each represent a difunctional aromatic hydrocarbon group having at most 20 carbon atoms which does not contain a mobile hydrogen atom, and n is an integer having a value of 0, 1 or 2; the radicals R ⁶ to R ¹⁰ each denote a group consisting of -NHCH ₂ CH =CH _{2 ,} -N (CH ₂ CH =CH ₂ ) ₂ , -OCH ₂ CH =CH ₂ , -CH ₂ CH =CH ₂ , -CH ₂ CH ₂ OCH = CH ₂ , - (C ₆ H ₄ ) -CH = CH ₂ , -O (C ₆ H ₄ ) -CH = CH ₂ , -CH ₂ (C ₆ H ₄ ) -CH = CH ₂ , -NH (C ₆ H ₄ ) -CH = CH ₂ , -N (CH ₂ CH = CH ₂ ) - (C ₆ H ₄ ) -CH = CH ₂ , -OR-OOC-C (R ') CH ₂ , -NH-R-NHCO-C (R ') = CH ₂ and an aryl group having at most 12 carbon atoms, wherein R represents an alkylene group having 2 to 5 carbon atoms and R' represents a hydrogen atom or a methyl group;
at least one of R ⁶ to R ^{10 contains} a -CH = CH ₂ group or a -C (CH ₃ ) = CH ₂ group.

The reactive organic phosphorus-based flame retardant (B) is stable in its energy state, scarcely evaporated upon kneading in the resin and molding, and further hardly decomposed due to heat and shear. Therefore, the molding properties are not impaired.

Preferably, the polyacetal resin (C) is an oxymethylene-oxyethylene copolymer or an oxymethylene polymer. According to these aspects of the invention, a thermal decomposition gas excellent in arc extinguishing ability is generated so that the arc is extinguished immediately. Therefore, the arc voltage is maintained.

Further, the invention proposes using an arc extinguishing resin molding according to any one of the above aspects in a circuit breaker having a fixed contact portion with a fixed contact piece, a movable contact portion with a movable contact piece for contact with the fixed contact portion and for performing closing and opening operations the fixed contact portion, and an arc extinguishing component that extinguishes an arc formed in the opening and closing operations between the fixed contact portion and the movable contact portion, the arc extinguishing component comprising the arc extinguishing resin molded body.

When using the arc extinguishing resin molding according to the invention in a circuit breaker, the arc developed between the contact pieces during the current interruption operation can be effectively canceled, and the pressure rise in the arc extinguishing component can be controlled. Therefore, the Disconnector small dimensions and shows excellent behavior during power interruption operation, including an overload interruption and a short-circuit interruption.

Effects of the invention

The arc extinguishing resin molded article of the present invention has a satisfactory strength, pressure resistance, heat resistance, flame retardancy and molding property. In addition, the resin molded article emits a thermal decomposition gas having a high arc extinguishing ability. As a result, the arc generated between the contact pieces in the current interruption operation is effectively extinguished, and the pressure in the arc extinguishing device is controlled to a small value. A circuit breaker in which the arc extinguishing resin molded body is used in the present invention is amenable to miniaturization and has an excellent power interruption performance including an overload interruption and a short-circuit interruption.

Brief description of the drawings

1 is a partially sectional perspective view of an example of a circuit breaker,

2 is a perspective view of an arc-extinguishing chamber used in the circuit breaker.

3 FIG. 12 is a cross-sectional view of an arc extinguishing component used in the circuit breaker. FIG.

Best embodiment of the invention

A resin composition for an arc extinguishing resin molded article of the present invention contains a polyolefin resin (A) in which a part of hydrogen atoms in a methylene chain is replaced by hydroxyl groups (-OH) and hydroxyl groups in an amount ranging from 0.2 to 0.7 mol, based on 1 mole of the methylene groups (-CH ₂ -), and also a reactive organic phosphorus-based flame retardant (B) containing at least one of -CH = CH ₂ or -C (CH ₃ ) = CH ₂ having an unsaturated end bond. The resin composition is subjected to cross-linking treatment by α-ray, γ-ray, X-ray or ultraviolet ray for crosslinking after a molding process in the resin molding.

The polyolefin resin (A) contains hydroxyl groups in an amount of 0.2 to 0.7 mol, and preferably 0.2 to 0.65 mol, based on 1 mol of the methylene groups. When the proportion of the hydroxyl groups in the above-defined ratio is less than 0.2, it is difficult to produce a thermal decomposition gas having a good arc extinction behavior in the thermal decomposition process, so that the arc can not be extinguished immediately. Further, the pressure in the arc-extinguishing member tends to increase in the arc extinguishing process. At the same time, the arc extinguishing component is polluted by an increased amount of free carbon, which impairs the electrical insulating capacity of the device. When the proportion of the hydroxyl groups in the polyolefin resin (A) exceeds 0.7 mol, the strength of the hydrogen bonds between the molecules is stronger than in the case of 0.7 mol or less. When the hydrogen bonds are stronger, the melting point of the polyolefin resin comes closer to the decomposition temperature. Thereby, the molding process becomes difficult due to thermal decomposition in kneading.

The resin composition further contains a polyacetal resin (C) in an amount in the range of 5 to 90 parts by weight based on 100 parts by weight of the polyolefin resin (A), wherein the polyacetal resin (C) is derived from oxymethylene structural units. in a proportion ranging from 75 to 100 mol%, and the polyacetal resin (C) is dispersed in the polyolefin resin (A) to form a microphase separation structure.

The polyolefin resin (A) preferably has a latent heat of decomposition of preferably at least 125.6 J / g (30 cal / g), more preferably at least 167.5 J / g (40 cal / g). The latent decomposition heat of the polyolefin resin (A) can be increased by increasing the proportion of hydroxyl groups in the resin. The latent heat of decomposition of the polyolefin resin in which a part of the hydrogen atoms in a methylene chain is replaced by hydroxyl groups and the hydroxyl groups in an amount of 0.2 to 0.7 mol, based on 1 mol of the methylene groups, is in the range of 125.6 to 209.3 J / g (30 to 50 cal / g). The latent heat of decomposition of a resin can be measured by heating to decompose the sample resin in an inert gas atmosphere.

A preferred polyolefin resin is an ethylene-vinyl alcohol copolymer which is particularly favorable because of its excellent arc extinguishing properties. While polyethylene exhibits low arc extinction behavior, poly (vinyl alcohol) can be added only to a limited extent in a molding process.

wobei die Reste R¹ bis R⁴ jeweils die Bedeutung CH₂=CY¹-Y²- haben oder eine monofunktionelle aromatische Kohlenwasserstoffgruppe, die ein Heteroatom enthalten kann, bedeuten und R⁵ eine difunktionelle aromatische Kohlenwasserstoffgruppe, die ein Heteroatom enthalten kann, bedeutet;
die Reste X¹ bis X⁴ jeweils eine Gruppe bedeuten, die aus -O-, -NH-, -(CH₂=CY¹-Y²)N- ausgewählt ist und mindestens einer der Reste X¹ bis X⁴ die Gruppe -NH- oder die Gruppe -(CH₂=CY¹-Y²)N- enthält;
mindestens eine der Reste R¹ bis R⁴ und der Reste X¹ bis X⁴ die Gruppe CH₂=CY¹-Y²- enthält;
Y¹ ein Wasserstoffatom oder eine Methylgruppe bedeutet; und
Y² eine Alkylengruppe mit 1 bis 5 Kohlenstoffatomen oder den Rest -COO-Y³- bedeutet, wobei Y³ eine Alkylengruppe mit 1 bis 5 Kohlenstoffatomen bedeutet. Chemische Formel 4

wobei in einem Molekül mindestens eine P-C-Bindung enthalten ist;
die Reste Ar¹ und Ar² jeweils eine difunktionelle aromatische Kohlenwasserstoffgruppe mit höchstens 20 Kohlenstoffatomen bedeuten, die kein mobiles Wasserstoffatom enthält, und n eine ganze Zahl mit einem Wert von 0, 1 oder 2 ist; die Reste R⁶ bis R¹⁰ jeweils eine Gruppe bedeuten, die aus -NHCH₂CH=CH_{2 ,} -N(CH₂CH=CH₂)₂, -OCH₂CH=CH₂, -CH₂CH=CH₂, -CH₂CH₂OCH=CH₂, -(C₆H₄)-CH=CH₂, -O(C₆H₄)-CH=CH₂, -CH₂(C₆H₄)-CH=CH₂, -NH(C₆H₄)-CH=CH₂, -N(CH₂CH=CH₂)-(C₆H₄)-CH=CH₂, -O-R-OOC-C(R')=CH₂, -NH-R-NHCO-C(R')=CH₂ und einer Arylgruppe mit höchstens 12 Kohlenstoffatomen ausgewählt ist, wobei R eine Alkylengruppe mit 2 bis 5 Kohlenstoffatomen bedeutet und R' ein Wasserstoffatom oder eine Methylgruppe bedeutet;
mindestens einer der Reste R⁶ bis R¹⁰ eine -CH=CH₂-Gruppe oder eine -C(CH₃)=CH₂-Gruppe enthält.The phosphorus-based reactive organic flame retardant (B) is an organic phosphorus compound having an unsaturated end bond, and is preferably a compound of the formulas (I) or (II). Chemical formula 3

wherein the radicals R ¹ to R ⁴ each have the meaning CH ₂ = CY ¹ -Y ² - or a monofunctional aromatic hydrocarbon group which may contain a heteroatom, and R ^{5 is} a difunctional aromatic hydrocarbon group which may contain a heteroatom means;
the radicals X ¹ to X ⁴ each represent a group selected from -O-, -NH-, - ⁽¹ -Y ² CH ₂ = CY) N- is selected and at least one of X ¹ to X ⁴ is the group - NH- or the group - (CH ₂ = CY ¹ -Y ² ) N-;
at least one of the radicals R ¹ to R ⁴ and the radicals X ¹ to X ^{4 contains} the group CH ₂ = CY ¹ -Y ² -;
Y ^{1 represents} a hydrogen atom or a methyl group; and
Y ^{2 represents} an alkylene group having 1 to 5 carbon atoms or the group -COO-Y ³ -, wherein Y ^{3 represents} an alkylene group having 1 to 5 carbon atoms. Chemical formula 4

wherein at least one PC bond is contained in a molecule;
the radicals Ar ¹ and Ar ² each represent a difunctional aromatic hydrocarbon group having at most 20 carbon atoms which does not contain a mobile hydrogen atom, and n is an integer having a value of 0, 1 or 2; the radicals R ⁶ to R ¹⁰ each denote a group consisting of -NHCH ₂ CH =CH _{2 ,} -N (CH ₂ CH =CH ₂ ) ₂ , -OCH ₂ CH =CH ₂ , -CH ₂ CH =CH ₂ , -CH ₂ CH ₂ OCH = CH ₂ , - (C ₆ H ₄ ) -CH = CH ₂ , -O (C ₆ H ₄ ) -CH = CH ₂ , -CH ₂ (C ₆ H ₄ ) -CH = CH ₂ , -NH (C ₆ H ₄ ) -CH = CH ₂ , -N (CH ₂ CH = CH ₂ ) - (C ₆ H ₄ ) -CH = CH ₂ , -OR-OOC-C (R ') CH ₂ , -NH-R-NHCO-C (R ') = CH ₂ and an aryl group having at most 12 carbon atoms, wherein R represents an alkylene group having 2 to 5 carbon atoms and R' represents a hydrogen atom or a methyl group;
at least one of R ⁶ to R ^{10 contains} a -CH = CH ₂ group or a -C (CH ₃ ) = CH ₂ group.

The organic phosphorus compound contains at least one of -CH = CH ₂ or -C (CH ₃ ) = CH ₂ , that is, an unsaturated end bond. This functional group should undergo binding with the polyolefin resin (A) upon irradiation with radioactive rays. Preferably, two or more unsaturated end bonds are contained in one molecule.

The group CH ₂ = CY ¹ -Y ² - in the compound of the formula (I) may have, for example, the following special meanings: CH ₂ = CH-CH ₂ -, CH ₂ = CH-CH ₂ CH ₂ CH ₂ -, CH ₂ = C (CH ₃ ) -CH ₂ -, CH ₂ = CHCOO-CH ₂ CH ₂ - and CH ₂ = C (CH ₃ ) COO-CH ₂ CH ₂ -
The monofunctional aromatic hydrocarbon group which may contain a hetero atom in the scope of R ¹ to R ⁴ is preferably an aromatic hydrocarbon group having 6 to 14 carbon atoms. Specifically, these include the following groups: -C ₆ H ₅ (phenyl group), -C ₆ H ₅ OH (hydroxyphenyl group), C ₆ H ₅ -C ₆ H ₅ OH (hydroxybiphenyl group), -CH ₂ C ₆ H ₅ (benzyl group), -α-C ₁₀ H ₇ - (α-naphthyl group) and -β-C ₁₀ H ₇ (β-naphthyl group).

The difunctional aromatic hydrocarbon group which may contain a hetero atom in the scope of R ₅ is preferably an aromatic hydrocarbon group having 10 to 14 carbon atoms. Specific examples of such groups include: -pC ₆ H ₄ -pC ₆ H ₄ -, -pC ₆ H ₄ -CH ₂ -pC ₆ H ₄ -, -pC ₆ H ₄ -C (CH ₃ ) ₂ -pC ₆ H ₄ , -pC ₆ H ₄ -C (= O) -pC ₆ H ₄ -, -pC ₆ H ₄ -SO ₂ -pC ₆ H ₄ - and 2,6-C ₁₀ H ₆ <(2,6-) naphthylene).

The aromatic hydrocarbon group mentioned in the specification and in the claims includes not only a purely aromatic hydrocarbon group such as the phenyl group and the -pC ₆ H ₄ -pC ₆ H ₄ group but also an aromatic hydrocarbon group having an oxygen or sulfur atom as Heteroatom contains, for. The hydroxyphenyl group and the -pC ₆ H ₄ -SO ₂ -pC ₆ H ₄ group.

Chemische Formel 6

Chemische Formel 7

As specific examples of the organic phosphorus compound of the formula (I), the compounds of the following structural formulas (I-1) to (I-18) can be listed. Chemical formula 5

Chemical formula 6

Chemical formula 7

The compounds listed above can be prepared according to the in WO-2005/012415 produce described method. For example, Compound (I-1) can be obtained by adding phosphorus oxychloride to dimethylacetamide (DMAc) and dropping into this solution a DMAc solution containing dissolved 4,4'-biphenylalcohol and dissolved triethylamine to react the ingredients with each other after which the reaction is followed by a mixed solution of allylamine and triethylamine.

In the compounds of the formula (II), specific examples of the aryl group having not more than 12 carbon atoms may be the following groups: -C ₆ H ₅ (phenyl group), -C ₆ H ₅ OH (hydroxylphenyl group), -C ₆ H ₅ -C ₆ H ₅ OH (hydroxybiphenyl group), -α-C ₁₀ H ₇ (α-naphthyl group) and -β-C ₁₀ H ₇ (β-naphthyl group).

Specific examples of the difunctional aromatic hydrocarbon group having at most 20 carbon atoms which does not contain a mobile hydrogen within Ar ¹ and Ar ² may be the following groups: -pC ₆ H ₄ -, -pC ₆ H ₄ -O-, -OpC ₆ H ₄ -O-, -pC ₆ H ₄ -pC ₆ H ₄ -, -pC ₆ H ₄ -CH ₂ -pC ₆ H ₄ -, -pC ₆ H ₄ -C (CH ₃ ) ₂ -pC ₆ H ₄ -, -pC ₆ H ₄ -C (= O) -pC ₆ H ₄ -, -pC ₆ H ₄ -SO ₂ -pC ₆ H ₄ - and 2,6-C ₆ H ₄ <(2, 6-naphthylene group). By a mobile hydrogen atom is meant a highly reactive hydrogen atom contained in a functional group, e.g. In -OH (hydroxyl group), -NHCO- (amide bond) or -NHCOO- (urethane bond), which readily forms a hydrogen bond and readily reacts at room temperature with metallic sodium and sodium hydride to produce hydrogen.

Chemische Formel 9

Chemische Formel 10

Chemische Formel 11

Specific examples of the organic phosphorus compound of the formula (II) include the compounds of the structural formulas (II-1) to (II-23). Among these compounds, compounds (II-1) to (II-12) represent examples of n = 0, that is, examples containing two phosphorus atoms in one molecule. The compounds (II-13) to (II-20) are examples of n = 1, that is, examples containing three phosphorus atoms in one molecule. The compounds (II-21) to (II-23) are examples of n = 2, wherein four phosphorus atoms are contained in one molecule. Chemical formula 8

Chemical formula 9

Chemical formula 10

Chemical formula 11

The compounds listed above can be according to a in WO-2005-087852 produce described method. For example, the compound (II-1) can be produced by reacting the starting materials 4,4'-dichlorobiphenyl with phosphorus oxychloride, followed by reaction with allyl bromide to introduce an unsaturated group at the end.

The reactive organic phosphorus-based flame retardant (B) is contained in the resin composition, preferably in an amount of 0.5 to 20% by weight, and more preferably 4 to 12% by weight. When the content of the phosphorus-based reactive organic flame retardant (B) is less than Q5% by weight, the flame retardant properties are scarcely improved, and besides, the low crosslinking density of the resin composition results in the physical properties of strength , Pressure resistance and heat resistance are hardly improved. When the proportion exceeds 20% by weight, the phosphorus-based organic flame retardant is so abundant that unreacted monomer and decomposition gases of the reactive phosphorus-based organic flame retardant may be present and bleeding of oligomeric substances may occur.

Further, resin composition used in the arc extinguishing resin molded article of the present invention further contains a polyacetal resin (C). Although a polyacetal resin generally generates a thermal decomposition gas which is very effective for extinguishing an arc, it presents difficulty in shaping by melt-kneading, that is, it has poor moldability. Since a polyacetal resin generates an abundant amount of thermal decomposition gas that provides a relatively high contribution to the pressure increase, the pressure in an arc extinguishing device tends to increase. By using the polyacetal resin in combination with the polyolefin resin (A), the arc extinguishing performance is improved without impairing the ductility of the resin composition. In addition, the pressure increase in an arc-extinguishing component in the arc extinguishing process is also suppressed.

The polyacetal resin (C) contains structural units derived from oxymethylene in a proportion of preferably 75 to 100 mol%, and more preferably in the range of 80 to 100 mol%. If the proportion of the structural units is less than 75 mol%, poor arc extinguishing performance results and a rapid extinguishing operation can not be performed.

A preferred polyacetal resin is an oxymethylene-oxyethylene copolymer or an oxymethylene polymer, which is particularly preferred because of its excellent arc extinguishing properties. In contrast, polyoxyethylene exhibits poor arc extinction behavior.

The polyacetal resin (C) is contained in an amount in the range of 5 to 90 parts by weight, and more preferably in the range of 7 to 88 parts by weight, based on 100 parts by weight of the polyolefin resin (A). When the proportion of the polyacetal resin (C) is less than 5 parts by weight in accordance with the ratio defined above, only a small effect by the polyacetal resin (C) can be expected, and the arc extinguishing performance is hardly improved. When the proportion exceeds 90 parts by weight, the amount of the thermal decomposition gas increases, whereby the pressure in the arc extinguishing component increases.

The resin composition used in the arc extinguishing resin molded article of the present invention may further comprise the above-mentioned resins, for example, a general-purpose thermoplastic resin may be contained. The proportion of such a resin is preferably in the range of 0 to 15 parts by weight, and more preferably in the range of 0 to 12 parts by weight, based on 100 parts by weight of the polyolefin resin (A).

Further, the resin composition used in the arc-quench resin molded article preferably further contains a radiation crosslinking agent. The contained radiation crosslinking agent forms a chemical bond with the resin upon irradiation with radioactive rays, whereby the resin is crosslinked in a three-dimensional network structure and the crosslinking density is increased. This improves physical properties including strength, pressure resistance and heat resistance.

Suitable radiation crosslinking agents include compounds that do not contain an aromatic ring and readily generate hydrogen gas, which are melamine compounds having a reactive functional group with a difunctional or higher functionality, including trimethallyl acrylate, triallyl acrylate, and isocyanato-tri (methyl) acrylate. In particular, a radiation crosslinking agent can be selected from the following products: triallyl isocyanurate, trimethallyl isocyanurate, an oligomer obtained by radical oligomerization of these isocyanurates, triallyl trimellitate, trimethallyl trimellitate, tetraallyl pyromellitate, tetramethallyl pyromellitate, N, N, N ', N ", N" -hexaallylmelamine , N, N, N ', N', N ", N" -hexamethallylmelamine and the like.

The radiation crosslinking agent is contained in the resin composition in an amount of preferably 0.5 to 20% by weight, and more preferably 1 to 12% by weight. When the proportion of the radiation crosslinking agent is less than 0.5% by weight, the crosslinking of the resin composite is hardly improved. If the proportion exceeds 20% by weight, the radiation crosslinking agent may bleed out.

Advantageously, the resin composition used in the arc extinguishing resin molded body contains one or more types of inorganic filler (D) selected from the group consisting of reinforcing fibers, barium titanate whiskers, fine silica particles, boehmite, talc, magnesium carbonate and a metal hydroxide. The presence of the inorganic filler improves the dimensional stability as well as the intensity, the pressure resistance and the heat resistance of the arc-quench resin molded article.

For example, the reinforcing fibers may be selected from glass fibers, carbon fibers and metal fibers, with glass fibers being preferred because of their strength and adhesiveness to the resin and the inorganic filler material. The reinforcing fibers may be used alone or in combination of two or more kinds. Furthermore, the fibers may be treated with a known surface treatment agent, e.g. As a silane coupling agent. The glass fibers are preferably surface-treated and further coated with a resin. This measure improves the adhesiveness of the resin in the resin composition.

The metal hydroxide is preferably dispersed in the polyolefin resin (A) because of its ability to suppress the pressure increase. The metal hydroxide is preferably selected from the group comprising aluminum hydroxide, boehmite and magnesium hydroxide having a grain diameter in the range of 1 to 10 μm.

The inorganic filler (D) is contained in the resin composition preferably in a proportion of 1 to 70% by weight, and more preferably 20 to 70% by weight. When the content of the inorganic filler (D) is less than 1% by weight, the effect of the inorganic filler is hardly obtained. When the proportion exceeds 70% by weight, the amount of the thermal decomposition gas decreases, which affects the arc extinguishing ability.

The resin composition of the arc extinguishing resin molded article of the present invention may further contain commonly used additives other than the above-mentioned substances, unless the additive significantly affects the properties intended by the present invention, that is, the above-described additives. H. the heat resistance, the pressure resistance, the arc extinguishing ability, the strength and the flame retardancy. The additives include, for example, nuclei, coloring agents, antioxidants, mold release agents, plasticizers, heat stabilizers, lubricants, UV absorbers and the like.

The arc extinguishing resin molded article of the present invention is completed by irradiating the molded resin composition with α-ray, γ-ray, X-ray or UV-ray.

The molding of the resin composition can be carried out by a known method. For example, after melt-kneading the resin composition for forming pellets, molding may be carried out by a known method of injection molding, extrusion, vacuum molding, blow molding and the like. The melt kneading may be carried out by using a commonly used melt kneading machine, e.g. A single-screw or twin-screw extruder, a Banbury mixer, a kneader, a mixing roll or the like. The kneading process is preferably carried out at a temperature in the range of 170 to 230 ° C. When the temperature is lower than 170 ° C, the melt-kneading is hardly performed. At a temperature higher than 230 ° C, the hydroxyl group dissociates in the resin composition, thereby decreasing extinction performance. In particular, the method described below proves to be favorable. A resin composition containing the polyolefin resin (A) and the polyacetal resin (C) is kneaded and molded under an inert gas atmosphere at a temperature of 180 to 220 ° C, followed by cooling to a temperature of 40 to 60 ° C. By this molding method, there can be obtained a resin molded article having a microphase separation structure in which the polyacetal resin (C) having a submicron size of 0.1 to 0.9 μm is dispersed in the polyolefin resin (A) in the configuration of a lake with islands , a hexagonal cylinder or slats. By forming the microphase separation structure, the polyacetal resin (C) can be easily thermally decomposed to emit a thermal decomposition gas having a high arc extinguishing ability, whereby the arc is rapidly extinguished. Since the crosslinking has not yet started at this stage, residues resulting from the molding process can be recycled.

After the resin molded body is obtained, irradiation with α-ray, γ-ray, X-ray or UV-ray is performed to obtain the arc-quench resin molded article. The microphase separation structure is fixed by the crosslinking process caused by the irradiation.

For the irradiation of the resin molded body, α rays, γ rays, X-rays or UV rays are used, of which γ-steels are preferred because they show an intensive penetration behavior and allow a homogeneous irradiation.

The irradiation dose is preferably at least 10 kGy, and more preferably 10 to 45 kGy. Irradiation in this range makes it possible to achieve an arc extinguishing resin molded article having the aforementioned favorable properties due to the crosslinking achieved by the irradiation. When the irradiation dose is less than 10 kGy, the three-dimensional network structure formed by the crosslink bonds is inhomogeneous, and unreacted crosslinking agent may bleed out. When the dose exceeds 45 kGy, internal stresses remain after irradiation, due to oxidation decomposition products in the resin molded body, which may cause distortion and contractions.

An arc quench resin molded article of the present invention thus obtained has excellent properties in terms of strength, pressure resistance, heat resistance, arc extinction behavior, and flame retardancy, and thus can be advantageously used in an arc extinguishing device of a circuit breaker.

Next, a circuit breaker in which the arc extinguishing resin molded body of the present invention can be used will be described.

The circuit breaker includes a fixed contact portion with a fixed contact piece, a movable contact portion with a movable contact piece that can come into contact with the fixed contact portion and perform opening and closing operations together with the fixed contact portion and an arc extinguishing component, the one in the Opening and closing operations between the fixed contact portion and the movable contact portion generated arc extinguished, wherein the arc extinguishing component comprises the above-described arc extinguishing resin moldings.

A specific example of such a circuit breaker is in the 1 to 3 shown. 1 is a perspective view partially showing a section. 2 is a perspective view of the arc extinguishing component. 3 is a sectional view of the circuit breaker.

According to 1 the circuit breaker comprises a fixed contact section 5 having a monolithic structure, wherein a power supply terminal 4 at one end and a U-shaped bend along a movable contact portion 1 are provided at the other end. Further, the circuit breaker comprises the movable contact portion 1 with a movable contact piece 6 that with a fixed contact piece 7 that is at the top of the U-bend 5a the fixed contact portion is provided, comes in contact. At the fixed contact section 5 is an arcing horn 9 attached, that between the movable contact piece 6 and the fixed contact piece 7 developed arc in the direction of the arc extinguishing component directs.

The arc extinguishing component consists of a grid 2 and an arc quenching chamber 13 , The grid 2 is composed of a plurality of layers (five layers in the figures), which, while maintaining a predetermined distance to the insulator 12 are stacked. The movable contact section 1 performs an opening and closing movement between a closed position indicated by a solid line and an open position indicated by a one-dot chain line through the V-shaped notch 2a in the grid 2 is formed, out. The arc extinguishing chamber 13 formed of an inventive arc extinguishing resin molded body is between the movable contact portion 1 and the grid 2 intended.

The in 1 and 3 illustrated insulating body 12 includes a pair of side walls 12a on the left and right side and connecting parts 12b and 12c that connect the side walls above and below. The insulator is monolithically formed of a melamine resin molding which is resistant to the arc. A plurality of grooves 14 with rectangular cross-section is on the opposite faces of the pair of side walls 12a educated. The grooves rise obliquely from the load side end (right side end in 3 ) at. The individual layers of the grid 2 are by press fitting to the grooves 14 adapted and provide a bridge between the left and right side walls 12a represents.

The arc extinguishing chamber 13 includes a pair of left and right side walls 13a and a front wall 13b with an arched shape covering the upper areas of the left and right sidewalls 13a along the V-shaped notch 2a in the grid 2 combines. The arc extinguishing chamber 13 further comprises a partition wall 15 which separates the arc extinguishing member from an opening-closing mechanism, and an insulating cover 16 that the fixed contact section 5 covered, wherein the partition wall and the insulating cover are monolithically formed in the arc-quenching chamber. The partition 15 is with a slot 15a provided along the path of the opening-closing movement of the movable contact portion. The insulating cover 16 is with a window 16a provided that the fixed contact piece 7 releases. The arc extinguishing chamber 13 is inside in the insulator 12 on the right side of 3 mounted, with the dividing wall 15 in contact with the right end surface of the sidewalls 12a of the insulating body 12 stands. The arc extinguishing chamber 13 resting on the fixed contact section 5 , with the insulating cover between them 16 is and is pressed by a main body cover (not shown in the figures) of the circuit breaker and fixed. In this mounted condition, the side walls cover 13a the arc extinguishing chamber 13 the leg portions of the grid 2 (the regions on both sides of the V-shaped notch) positioned on both sides of the movable contact portion on the inside. The front wall 13b is located behind the V-shaped notch 2a the topmost layer of the grid 2 , as in 3 is shown.

In the current interruption process, in the structure described above, an arc is generated between the movable and fixed contact pieces 6 and 7 , and the arc moves to the grid 2 there and is wiped out there. Since the two leg portions of the grid 2 through the side walls 13a the arc extinguishing chamber 13 are shielded and shielded against the arc in this current interruption process, melting and sputtering of these areas of the grid by the arc is prevented, and further, a thermal decomposition gas from the side walls 13a generated and emitted in the vicinity of the arc, which promotes cooling of the arc and its rapid extinction.

Examples

Hereinafter, the present invention will be described in detail with reference to some preferred embodiments. However, the invention is not limited to these examples.

example 1

First, 67 parts by weight of polyolefin resin (EVAL-L104B ^®, mfd. By Kuraray Co., Ltd.) containing 0.58 mole of hydroxyl groups, based on 1 mole of methyl groups, and 25 parts by weight of a polyoxymethylene oxyethylene copolymers (Tenac-C 4520 ^®, mfd. by Asahi Kasei Corporation) with a content of 90 mol% of structural units derived from oxymethylene melted and mixed. Subsequently, 8 parts by weight of the compound of the formula (I-14) was added as a phosphorus-based reactive organic flame retardant. The resulting mixture was kneaded at 220 ° C using a side-flow type twin-screw extruder (product of Japan Steel Works, Ltd.) to form resin pellets. The resin pellets were dried at 80 ° C for 7 hours, and then molded at a resin temperature of 215 ° C and a mold temperature of 50 ° C using an injection molding machine (type α50C ^® Fa. FANUC Ltd.). The cross section of the molded article was observed by scanning electron microscopy. The formation of a microphase separation structure was confirmed, showing a spherulite structure with a lamellar configuration and a homogeneous sea-island structure.

Subsequently, the molded body was irradiated with γ-rays from a cobalt 60 source at a dose of 25 kGy. Thus, the arc extinguishing resin molded article of Example 1 was obtained. The cross section of this arc extinguishing resin molded article was observed by a scanning electron microscope. The formation of a microphase separation structure was confirmed, showing a spherulite structure with a lamellar configuration and a homogeneous sea-island structure.

Example 2

First, 50 parts by weight of a polyolefin resin (EVAL-L104B ^®, mfd. By Kuraray Co., Ltd.) containing 0.58 mole of hydroxyl groups, based on 1 mole of methyl groups, and 20 parts by weight of a polyoxymethylene -Oxyethylen copolymers (Tenac-C 4520 ^®, mfd. by Asahi Kasei Corporation) with a content of 90 mol% of structural units were derived from oxymethylene melted and mixed. Then 10 parts by weight of boehmite (BMT-10 ^®, manufactured by. Kawai Lime Co., Ltd.), 15 parts by weight silane treated glass fibers (03.JAFT2Ak25 ^®, manufactured by. Asahi Fiber Glass Co ., Ltd.) as inorganic filler materials and 5 parts by weight of the compound of the formula (II-3) as a phosphorus-based reactive organic flame retardant. The resulting mixture was kneaded at 220 ° C using a side-flow type twin-screw extruder (product of Japan Steel Works, Ltd.) to form resin pellets. The pellets were dried for 7 hours at 80 ° C and then at a resin temperature of 215 ° C and a mold temperature of 50 ° C using an injection molding machine (Type α50C ^®, mfd. By FANUC Ltd.) deformed. The cross section of the molding was with a Scanning electron microscope considered. The formation of a microphase separation structure confirming spherulite structure with a lamellar configuration and a homogeneous sea-island structure was confirmed.

Subsequently, the molded body was irradiated with γ-rays from a cobalt 60 source at a dose of 25 kGy. Thus, the arc extinguishing resin molded article of Example 2 was obtained. The cross section of this arc extinguishing resin molded article was observed by a scanning electron microscope. The formation of a microphase separation structure was confirmed, showing a spherulite structure with a lamellar configuration and a homogeneous sea-island structure.

Example 3

First, 53 (Kuraray Co., Ltd. EVAL-L104B ^®, manufactured and sold.) With a content of 0.58 mol hydroxyl groups, based on 1 mol of methyl groups were parts by weight of a polyolefin resin, and 20 parts by weight of a polyoxymethylene -Oxyethylen copolymers (Tenac-C 4520 ^®, mfd. by Asahi Kasei Corporation) with a content of 90 mol% of structural units were derived from oxymethylene, melted at 220 ° C under a nitrogen gas atmosphere and mixed. Subsequently, 15 parts by weight of boehmite (BMT-10 ^®, mfd. By Kawai Lime Co., Ltd.) as an inorganic filler and 12 parts by weight of the compound of formula (I-18) as a reactive organic flame retardant Phosphorus-based added. The resulting mixture was kneaded at 220 ° C using a side-flow type twin-screw extruder (product of Japan Steel Works, Ltd.) under nitrogen gas to form resin pellets. The pellets were dried for 7 hours at 80 ° C and then molded under a nitrogen gas atmosphere at a resin temperature of 215 ° C and a mold temperature of 50 ° C using an injection molding machine (Type α50C ^®, mfd. By FANUC Ltd.). The cross section of the molded article was observed with a scanning electron microscope. The formation of a microphase separation structure was confirmed, showing a spherulite structure with a lamellar configuration and a homogeneous sea-island structure.

Subsequently, the molded body was irradiated with γ-rays from a cobalt 60 source at a dose of 25 kGy. Thus, the arc extinguishing resin molded article of Example 3 was obtained. The cross section of this arc extinguishing resin molded article was observed by a scanning electron microscope. The formation of a microphase separation structure was confirmed, showing a spherulite structure with a lamellar configuration and a homogeneous sea-island structure.

Comparative Example 1

The resin pellets of Comparative Example 1 were obtained by kneading under the same conditions as in Example 1, except that no reactive phosphorus-based organic flame retardant was blended. The obtained pellets were dried for 7 hours at 80 ° C and then at a resin temperature of 215 ° C and a mold temperature of 50 ° C using an injection molding machine (Type α50C ^®, mfd. By FANUC Ltd.) deformed. Thus, the arc extinguishing resin molded body of Comparative Example 1 was obtained.

Comparative Example 2

The resin pellets of Comparative Example 2 were obtained by kneading under the same conditions as in Example 2, except that no reactive phosphorus-based organic flame retardant was blended. The obtained pellets were dried for 7 hours at 80 ° C and then at a resin temperature of 215 ° C and a mold temperature of 50 ° C using an injection molding machine (Type α50C ^®, mfd. By FANUC Ltd.) deformed. In this way, the arc extinguishing resin molded article of Comparative Example 2 was obtained.

Comparative Example 3

The arc-extinguishing resin molded body of Comparative Example 3 was obtained in the same manner as in Example 2 except that the phosphorus-based organic reactive flame retardant used in Example 2 was replaced with a phosphorus-based organic flame retardant which was was an additive type and had no reactivity (HCA- ^HQ® , product of Sanko Chemical Industry Co., Ltd.)

Comparative Example 4

The arc extinguishing resin molded article of Comparative Example 4 was obtained in the same manner as in Example 2, except that the reactive organic flame retardant used in Example 2 was replaced phosphorus-based by a bromine flame retardant (Great Lakes PDBS-80 ^®, Product of Great Lakes Chemical Corporation).

Comparative Example 5

The arc extinguishing resin molded article of Comparative Example 5 was obtained in the same manner as in Example 2, except that the polyolefin resin (EVAL-L104B ^®, product Kuraray Co., Ltd. of Fa.) With a content of 0.58 mol Hydroxyl groups, based on 1 mole of methylene groups used in Example 2, by a polyethylene resin (HJ362 ^® , product of Messrs. Nippon Polyethylene Corporation) was replaced.

Comparative Example 6

First, 25 (Japan U-PICA Co., Ltd. 7527 ^®, manufactured by.) Of a styrene-vinyl acetate were parts by weight of an unsaturated polyester resin, 35 parts by weight of Al (OH) _3, 5 parts by weight Copolymers, 0.3 parts by weight of the polymerization initiator, tert-butyl peroxide-Z and 4.7 parts by weight of a viscosity adjusting agent kneaded using a kneader. When kneading, 35 parts by weight of an inorganic filler in the form of silane-treated glass fibers (03.JAFT2Ak25 ^®, mfd. By Asahi Fiber Glass Co., Ltd.) was added and dispersed. A molding material was obtained. The molding compound was molded and polymerized at a temperature in the range of 140 to 150 ° C. Thus, the arc extinguishing resin molded body of Comparative Example 6 was obtained.

Comparative Example 7

Resin pellets were prepared by kneading 99.8 parts by weight of nylon 6 resin (UBE Nylon 1015B ^®, mfd. By Ube Industries, Ltd.) and 0.2 parts by weight of an antioxidant (IRGANOX 1010 ^®, a product of Nihon Ciba-Geigy K.K.). The resin pellets were dried 4 hours at 105 ° C and then at a resin temperature of 260 ° C and a mold temperature of 85 ° C using an injection molding machine (type, α50C ^®, mfd. By FANUC Ltd.) deformed. Thus, the arc extinguishing resin molded body of Comparative Example 7 was obtained.

The molding properties of the arc-extinguishing resin moldings of Examples 1 to 3 and Comparative Examples 1 to 7 were evaluated. The arc extinguishing resin moldings were subjected to short circuit tests, heat resistance tests, and flame retardant tests wherein the moldings for the arc quenching chamber 13 a circuit breaker as shown in 1 were used.

In the short-circuit test, an electric current of 3-phase 440 V / 50 kA was passed through the contact pieces in the closed state. Subsequently, the movable contact portion was opened to generate an arc current. The test included the interruption characteristics of the arc current (arc extinguishing behavior), the breakage and the damage of the arc extinguishing component (pressure resistance) and the surface conditions (heat resistance).

The current interruption characteristics were said to be "acceptable" when the short circuit current was successfully interrupted.

Shaping properties were said to be "acceptable" if no visualization of bubbles or "drooling" occurred on visual inspection.

The flame retardant properties were evaluated according to the UL-94 test as follows. A test specimen (length 5 inches, width 1/2 inches and thickness 3.2 mm) was made according to UL-94. The specimen was placed vertically and placed in contact with the flame of a Bunsen burner for 10 seconds. The inflammation time was recorded. After extinguishing, the specimen was again brought into contact with the flame for 10 seconds and the ignition time was recorded again. A rating was made in accordance with UL-94 on the basis of the total time of ignition, post-annealing time after the second erasure, and burning dripping (inflammation of cotton wool).

The metal contamination state was evaluated by measuring the contact resistance after leaving the test specimen in an environment of 120 ° C for 300 hours. When the contact resistance was not higher than 50 mΩ, the metal contamination state was called "acceptable".

The results of the tests described above are summarized in Table 1. Table 1 Short-circuit test Power interruption characteristic (Arc extinguishing behavior) Breakage and damage (pressure resistance) Surface condition (heat resistance) molding properties Flame Retardant Texture (UL-94) metal contamination example 1 Acceptable (good current interruption properties) Acceptable (no damage) Well Well V-0 Acceptable Example 2 Acceptable (good power interruption characteristics) Acceptable (no damage) Well Well V-0 Acceptable Example 3 Acceptable (good power interruption characteristics) Acceptable (no damage) Well Well V-0 Acceptable Comparative Ex. 1 Acceptable (good current interruption properties) damage Well Well HB Acceptable Comparative Ex. 2 Acceptable (good current interruption properties) damage Well Well HB Acceptable Comparative Ex. 3 Acceptable (good current interruption properties) damage Well Well V-2 Unacceptable Comparative Ex. 4 Acceptable (good current interruption properties) damage Well Well V-0 Unacceptable Vergl.bsp. 5 unacceptable damage Well Well HB Acceptable Comparative Ex. 6 Acceptable (good current interruption properties) damage Well Bad (burrs) V-1 Acceptable Comparative Ex. 7 Acceptable (good current interruption properties) damage Well Bad ("Drooling") HB Acceptable

From the results of Table 1, it can be seen that the arc extinguishing resin moldings of Examples 1 to 3 were good in flame retardancy, heat resistance and molding properties. The circuit breakers using the arc extinguishing components from these arc extinguishing resin moldings effectively result in extinction of the arc developed between the contact pieces in the current interruption process. There was no damage to the arc hole chamber due to the arc extinguishing process.

Claims (7)

An arc extinguishing resin molded article comprising a resin composition, said resin composition containing: a polyolefin resin (A) in which a part of hydrogen atoms in a methylene chain is replaced by hydroxyl groups and hydroxyl groups in an amount ranging from 0.2 to 0.7 mol, based on 1 mole of the methylene groups are included; A reactive, organic phosphorus-based flame retardant (B) which contains at least one of the groups -CH = CH ₂ or -C (CH ₃ ) = CH _2, ie an unsaturated end bond; and a polyacetal resin (C) in an amount in the range of 5 to 90 parts by weight based on 100 parts by weight of the polyolefin resin (A), wherein the polyacetal resin (C) has structural units derived from oxymethylene in one Content in the range of 75 to 100 mol%, and the polyacetal resin (C) is dispersed in the polyolefin resin (A) to form a microphase separation structure; wherein the resin composition after forming into the resin molded body was subjected to irradiation by α-ray, γ-ray, X-ray or ultraviolet ray for crosslinking. The arc extinguishing resin molded article according to claim 1, wherein said resin composition further contains one or more types of inorganic filler (D) selected from the group consisting of glass fibers, barium titanate whiskers, silica gel fine particles, boehmite, talcum, magnesium carbonate and a Metal hydroxide, wherein the proportion of the inorganic filler is in the range of 1 to 70 wt .-%. An arc extinguishing resin molded article according to claim 1 or 2, wherein said polyolefin resin (A) has a latent decomposition heat of at least 125.6 J / g. An arc extinguishing resin molded article according to any one of claims 1 to 3, wherein the polyolefin resin (A) is an ethylene-vinyl alcohol copolymer. The arc extinguishing resin molded article according to any one of claims 1 to 4, wherein the reactive organic phosphorus-based flame retardant (B) is an organic phosphorus compound of the formula (I) and / or the formula (II) and this agent is used in the resin composition in an amount in the range of 0.5 to 20 wt .-% is included. Chemical formula 1

where the radicals R ¹ to R ⁴ each have the meaning CH ₂ = CY ¹ -Y ² - or a monofunctional aromatic hydrocarbon group which may contain a heteroatom, and R ^{5 is} a difunctional aromatic hydrocarbon group which may contain a heteroatom, X ¹ to X ⁴ each represent a group consisting of -O-, -NH-, - (CH ₂ = CY ¹ -Y ² ) N- is selected and at least one of the radicals X ¹ to X ^{4 contains} the group -NH- or the group - (CH ₂ = CY ¹ -Y ² ) N-; at least one of the radicals R ¹ to R ⁴ and the radicals X ¹ to X ^{4 contains} the group CH ₂ = CY ¹ -Y ² -; Y ^{1 represents} a hydrogen atom or a methyl group; and Y ^{2 represents} an alkylene group having 1 to 5 carbon atoms or -COO-Y ³ -, wherein Y ^{3 represents} an alkylene group having 1 to 5 carbon atoms; Chemical formula 2

wherein at least one PC bond is contained in a molecule; the radicals Ar ¹ and Ar ² each represent a difunctional aromatic hydrocarbon group having at most 20 carbon atoms which does not contain a mobile hydrogen atom, and n is an integer having a value of 0, 1 or 2; the radicals R ⁶ to R ¹⁰ each denote a group consisting of -NHCH ₂ CH =CH ₂ , -N (CH ₂ CH =CH ₂ ) ₂ , -OCH ₂ CH =CH ₂ , -CH ₂ CH =CH ₂ , -CH ₂ CH ₂ OCH = CH ₂ , - (C ₆ H ₄ ) -CH = CH ₂ , -O (C ₆ H ₄ ) -CH = CH ₂ , -CH ₂ (C ₆ H ₄ ) -CH = CH ₂ , -NH (C ₆ H ₄ ) -CH = CH ₂ , -N (CH ₂ CH = CH ₂ ) - (C ₆ H ₄ ) -CH = CH ₂ , -OR-OOC-C (R ') CH ₂ , -NH-R-NHCO-C (R ') = CH ₂ and an aryl group having at most 12 carbon atoms, wherein R represents an alkylene group having 2 to 5 carbon atoms and R' represents a hydrogen atom or a methyl group; and at least one of R ⁶ to R ^{10 contains} a -CH = CH ₂ group or a -C (CH ₃ ) = CH ₂ group. An arc extinguishing resin molded article according to any one of claims 1 to 5, wherein the polyacetal resin (C) is an oxymethylene-oxyethylene copolymer or an oxymethylene polymer. Use of an arc extinguishing resin molded article according to any one of claims 1 to 6 in a circuit breaker comprising a fixed contact portion with a fixed contact piece, a movable contact portion with a movable contact piece for contact with the fixed contact portion, and performing closing and opening operations with the fixed contact portion , and an arc-extinguishing member that extinguishes an arc formed in the opening and closing operations between the fixed contact portion and the movable contact portion, the arc-extinguishing member comprising the arc-extinguishing resin molded body.

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