JP4703254B2 - Polyamide resin composition for breakers - Google Patents

Description

  The present invention relates to a polyamide resin composition that is excellent in flame retardancy, glow wire characteristics, and tracking characteristics, and that is suitable for use as a safety breaker and an earth leakage breaker incorporated in electrical wiring.

  Safety breaker, ampere breaker, earth leakage breaker: ELB (Earth Leakage Circuit Breaker), wiring breaker: MCB (Miniature Circuit Breaker), MCCB (Molded Case Circuit Breaker), N circuit breaker (F) Various breakers such as machine breaker (motor breaker) and slim breaker (one-touch breaker, one-touch earth leakage breaker) are designed to cut off the power supply when a current exceeding the specified level flows or when abnormalities such as shaking or heat generation are detected. is there. It is an electrical / electronic component built into electrical wiring, and is indispensable for ensuring the safety of electrical wiring.

Conventionally, a material for a breaker has been a thermosetting resin such as a phenol resin. However, since the productivity is low and the cost is high, switching to a thermoplastic resin is being studied.
Since it is a material mainly used for the housing, it has flame retardancy standard V-2 or higher in the UL 94 test, IEC 60695- Pass 960 ° C. with 1.6 mm thickness in GWFI (Glow-Wire Flammability Temperature) of 2-12 Glow Wire Test, and CTI (Comparative Tracking Index) in tracking resistance test of IEC 60112 is preferably 3 V and preferably 500 V or more. There are requirements such as. In addition, as a trend of the times, non-halogen type hope has been made as a flame retardant.

  As a non-halogen type flame retardant polyamide resin, JP-A-53-31759 (Patent Document 1) discloses a polyamide resin composition comprising a polyamide resin and melamine cyanurate. However, there is a description that glass fiber may be used in combination, but there is no specific disclosure in the examples. There is no description about GWFI or CTI. Moreover, there is no description about the viscosity number of the polyamide resin to be used.

  Patent documents 2-3 exist as patent documents which used together fillers, such as melamine cyanurate and glass fiber. Patent Document 2 discloses a reinforced polyamide molding material containing melamine and / or melamine cyanurate and unsized glass fibers. The invention discloses the influence on GWFI with or without sizing of glass fiber. However, although there is a description of short pulverized glass fiber, there is no clear description of the effect of glass fiber length on GWFI. In addition, as for the relative viscosity of the polyamide used, there is only a description in the examples that polyamide 66 having a relative viscosity of 3.0 and polyamide 6 having a relative viscosity of 2.9 are used. There is no description on the impact on Moreover, there is no description that it can be used suitably for a breaker.

Patent Document 3 discloses a flameproof thermoplastic molding material comprising a fibrous filler treated with polyamide, melamine cyanurate, a silane compound having a specific fiber length and distribution.
Show that silane-treated fibrous filler with specific fiber length and distribution (arithmetic mean (d50 value) 70-200 μm, d10 value 60 μm or less, d90 value 350 μm or less) gives good results to GWFI Yes. However, the resin composition has a CTI of around 475 V and cannot satisfy the tracking resistance characteristics required for the current breaker (or the electrical insulation characteristics after the breaker breaking test). On the other hand, “The polyamide of the molding material according to the invention usually has a specific viscosity ηrel of 1.7 to 5.0, corresponding to a K value of 50 to 96. ηrel 2.3 to 4.5, in particular 2.5. Polyamides having ˜4.0 are used preferentially ”, and in the examples only polyamide 6 with a viscosity number of 145 and polyamide 66 with a viscosity number of 151 are shown. There is no description about the influence of viscosity number (molecular weight) on UL94 or GWFI. "The molding material is suitable for the production of all kinds of fibers, films and molded bodies used as current breakers, auxiliary switches, relay switches and plug joints in the electrically insulating region," the current breaker is described. The various uses are listed only.

JP-A-53-31759 Japanese Patent Publication No. 07-560008 Japanese National Patent Publication No. 11-513059

  An object of the present invention is to provide a polyamide resin composition that is excellent in flame retardancy, glow wire characteristics, and tracking characteristics, and that is suitable for use as a safety breaker or an earth leakage breaker incorporated in electrical wiring.

In order to solve the problem, in particular, using a low molecular weight polyamide, and simultaneously adding a short glass filler has the effect of reducing the combustion flame and shortening the burning time in the glow wire test. It was found that the fiber length and the surface treatment agent were greatly involved in the formation of conductive paths in the CTI test, and at the same time, a polyamide resin composition with significantly improved glow wire characteristics and tracking characteristics could be obtained. did.
That is, the gist of the present invention is as follows.
(A) 0.5 to 35 parts by weight of (B) triazine flame retardant and (C) not surface-treated or surface-treated with an acid compound with respect to 100 parts by weight of polyamide resin having a viscosity number of 70 to 140 ml / g It consists of 10 to 60 parts by weight of a glass-based filler, the glass-based filler is dispersed in a number average fiber length of 20 to 70 μm, and is in a polyamide resin composition for breakers having the following properties.
a) When performing a 20 mm vertical combustion test according to UL 94, flame retardancy is V-2 or higher b) Performing a 960 ° C. glow wire flammability test (1.6 mm thickness) according to IEC 60695-2-12 When the tracking resistance test (3 mm thickness) is performed according to IEC 60112, the comparative tracking index (CTI) is 500 V or more.

  Thus, the polyamide resin composition of the present invention is an electrical insulating material excellent in flame retardancy, glow wire characteristics and tracking resistance characteristics, and can be used particularly as a material for electrical and electronic parts for breakers.

Hereinafter, the present invention will be described in detail.
(A) Polyamide resin As the polyamide resin (A) in the present invention, a polyamide obtained by polycondensation of a lactam having a three-membered ring, a polymerizable ω-amino acid, or a dibasic acid and a diamine can be used. . Specifically, polymers such as ε-caprolactam, aminocaproic acid, enanthractam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone, hexamethylenediamine, nonamethylene Obtained by polycondensation with diamines such as diamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine, and dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecanedioic acid, and glutaric acid. Polymers or copolymers thereof, for example polyamide 4, 6, 7, 8, 11, 12, 6.6, 6.9, 6.10, 6.11, 6.12, 6T, 6/6. 6, 6/12, 6 / 6T, 6T / 6I, MXD6, etc., and multiple types of polyamide resins can be used. . Particularly preferred polyamide resins in the present invention include polyamide 6, copolymerized polyamide 6/66 or 66/6, 6/69 and / or polyamide 66 from the viewpoint of flame retardancy, mechanical strength and moldability. The terminal of the polyamide resin in the present invention may be sealed with a carboxylic acid or an amine compound also for molecular weight adjustment.

Also, 70 the degree of polymerization in the range of polyamide resin used in the present invention is, namely those having a viscosity number in a specific range, in accordance with JIS K6933, 96% 1% concentration sulfuric acid, at a value measured at a temperature 23 ° C. 140ml / g der is, good Mashiku is 72~130ml / g. When the viscosity number is lower than 70 ml / g, the melt strength is small, so that the mechanical strength is lowered. On the other hand, if the viscosity number is higher than 140 ml / g, it is difficult to satisfy the required characteristics for breaker application in the glow wire characteristics.

(B) Triazine Flame Retardant Examples of the (B) triazine flame retardant in the present invention include compounds represented by the following general formula (1) or (2), melamines, and melamine cyanurate.

(Wherein R ^{1 to} R ⁶ each represent a hydrogen atom or an alkyl group)
Specific examples of the compound represented by the general formula (1) include cyanuric acid, trimethyl cyanurate, triethyl cyanurate, tri (n-propyl) cyanurate, methyl cyanurate, diethyl cyanurate and the like. Specific examples of the compound represented by the general formula (2) include isocyanuric acid, trimethyl isocyanurate, triethyl isocyanurate, tri (n-propyl) isocyanurate, diethyl isocyanurate, methyl isocyanurate and the like.

  Examples of melamines include melamine, melamine derivatives, compounds having a structure similar to melamine, and melamine condensates. Specific examples of melamines include melamine, ammelide, ammelin, formoguanamine, guanylmelamine, cyanomelamine, arylguanamine, melam, melem, melon and the like.

Examples of melamine cyanurate include equimolar reaction products of cyanuric acid and melamine.
Moreover, some of the amino groups or hydroxyl groups in melamine cyanurate may be substituted with other substituents. Melamine cyanurate can be obtained, for example, by mixing an aqueous solution of cyanuric acid and an aqueous solution of melamine, reacting at 90 to 100 ° C. with stirring, and filtering the produced precipitate, and is a white solid. It is preferable to grind and use on powder. Of course, a commercially available product can be used as it is or after being pulverized.

  As the triazine flame retardant, preferably, cyanuric acid, isocyanuric acid, melamine, melamine cyanurate, melem cyanuric acid, and the like, from the point that there is no inconvenience such as blooming that the decomposition product is raised on the surface of the molded product, More preferably, an equimolar reaction product of cyanuric acid represented by melamine cyanurate and melamine can be used.

  The compounding amount of the triazine flame retardant is 0.5 to 35 parts by weight with respect to 100 parts by weight of the polyamide resin. When the blending amount of the triazine flame retardant is less than 0.5 parts by weight, a flame retardant effect is not expected. When the amount is more than 35 parts by weight, it is easy to disassemble at the time of molding and the occurrence of trouble is predicted. The blending amount of the triazine-based flame retardant is preferably 1 to 20 parts by weight from the viewpoint of the balance between flame retardancy, glow wire characteristics, tracking resistance characteristics, and mechanical characteristics.

(C) Glass-based fillers (C) Glass-based fillers (glass fibers, pulverized glass fibers (milled fibers), glass flakes, glass beads, etc.) used in the present invention are usually used for thermoplastic resins. Two or more of them may be used in combination, but pulverized glass fibers and glass beads are preferred because of their short burning time in the glow wire test.

  The glass filler should be dispersed with a number average fiber length of 20 to 70 μm, preferably 25 to 60 μm. If the number average fiber length is less than this range, the mechanical strength / rigidity will decrease. If the number average fiber length exceeds this range, the CTI value will decrease, and the burning time after contact with the rod in the GWFI test (after contact with the red hot rod) will decrease. Since it becomes long, it is not preferable. Here, the number average fiber length of the glass-based filler varies depending on the shape of the filler, but is usually represented by the maximum dimension. For example, in the case of glass fibers of fibrous fillers, crushed glass fibers, glass flakes of plate fillers, etc., the maximum dimension for individual particles (maximum value of the distance between two points on the particle surface) is measured, Similarly, in the case of a substantially spherical glass bead, the maximum diameter of each individual substantially spherical sphere is measured, and the number average thereof is calculated as the “number average fiber length”. When fillers with different shapes are used in combination, the number average fiber length measured and calculated for each shape is multiplied by the blending ratio for each shape, and the average is obtained as the number average fiber length of the filler .

  The glass filler is preferably treated with a surface treatment agent or a sizing agent from the viewpoint of mechanical strength. However, in the tracking resistance test, a surface treatment agent containing a low molecular weight organic component present on the surface of the filler tends to form a conductive path and tends to lower the CTI value. Therefore, when importance is attached to tracking resistance, it is preferable that the glass-based filler is not subjected to surface treatment. In general, it is necessary to select a surface treatment agent and a sizing agent treatment on the balance between mechanical strength, molding surface smoothness, and the like and tracking resistance.

Examples of the surface treatment agent include acid compounds. Specific examples of the acid compound used for the surface treatment include hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, phosphorous acid, boric acid and the like, and preferably phosphorous acid and the like in terms of handling. As a method of surface treatment with an acid compound, for example, an acid compound is diluted with water or a solvent to obtain an acid aqueous solution or the like, a glass-based filler is immersed in the acid aqueous solution or the like, filtered and dried, The method of spraying etc. on a glass-type filler and drying is mentioned, Preferably, the method of immersing in an acid aqueous solution, drying after filtration is mentioned. Further, it can be sufficiently washed with water after the acid treatment.

  The compounding quantity of a glass type filler is 10-60 weight part with respect to 100 weight part of polyamide resins, and 15-55 weight part is more preferable. If the blending amount is less than 10 parts by weight, the mechanical properties for a breaker cannot be exhibited. When the amount is more than 60 parts by weight, the glow wire characteristics are rejected.

  As a method of blending the triazine-based flame retardant and the glass-based filler with the polyamide resin, it can be performed by various known means at an arbitrary stage until immediately before the final molded product is molded. The simplest method is a method in which a polyamide resin, a triazine flame retardant and a glass filler are simply dry blended, and the resulting dry blend is pelletized by melt mixing extrusion. As another method, a master pellet in which a triazine-based flame retardant or inorganic filler larger than a predetermined amount is kneaded with a polyamide resin is prepared in advance, and this is dry blended with a dilution polyamide resin. A polyamide resin composition can be obtained.

  In addition, pigments, dyes, nucleating agents, mold release agents, stabilizers, antistatic agents and other known additives can be blended and kneaded with the resin composition in the present invention. In particular, an amide mold release agent such as a carboxylic acid amide wax or a bisamide compound of ethylene bisstearyl amide, which also serves as a dispersion of a flame retardant, for example, 0.01 to 0.4 parts by weight with respect to 100 parts by weight of the polyamide resin, More preferably, 0.1 to 0.3 parts by weight is added because productivity at the time of injection molding of a breaker or the like is increased without deteriorating flame retardancy, glow wire characteristics and tracking resistance characteristics.

  The carboxylic acid amide wax is obtained by a dehydration reaction of a mixture of a higher aliphatic monocarboxylic acid and a polybasic acid and a diamine. The higher aliphatic monocarboxylic acid is preferably a saturated aliphatic monocarboxylic acid having 16 or more carbon atoms and a hydroxycarboxylic acid, and examples thereof include palmitic acid, stearic acid, behenic acid, montanic acid, 12-hydroxystearic acid and the like. It is done.

  The polybasic acid is a dibasic acid or higher carboxylic acid such as malonic acid, succinic acid, adipic acid, sebacic acid, pimelic acid, azelaic acid or the like, and phthalic acid, terephthalic acid or the like. Examples thereof include aromatic dicarboxylic acids and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and cyclohexylsuccinic acid. Examples of the diamine include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, metaxylylenediamine, tolylenediamine, paraxylylenediamine, phenylenediamine, and isophoronediamine. .

  The carboxylic acid amide wax in the present invention can be obtained at any softening point by changing the mixing ratio of the polybasic acid to the higher aliphatic monocarboxylic acid used in the production thereof. The mixing ratio is preferably in the range of 0.18 mol to 1.0 mol with respect to 2 mol of the higher aliphatic monocarboxylic acid. The amount of diamine used is preferably in the range of 1.5 mol to 2.0 mol with respect to 2 mol of the higher aliphatic monocarboxylic acid, and varies according to the amount of polybasic acid used.

  Bisamide compounds include diamine and fatty acid compounds such as N, N'-methylenebisstearic acid amide and N, N'-ethylene bisstearic acid amide, or dioctadecyl diamides such as N, N'-dioctadecyl terephthalic acid amide. Mention may be made of basic acid amides.

  In producing molded products such as breaker casings, covers, separators, and handles using the polyamide resin composition of the present invention, the polyamide resin composition such as the dry blend and pellets is molded into various moldings such as an injection molding machine. It can be carried out according to a conventional method of supplying to a machine, pouring into a mold, cooling and taking out.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited to a following example, unless the summary is exceeded. In the examples described below, the characteristics of each component used and the evaluation test method for the obtained composition are as follows.

[Ingredients used in Examples]
A-1) Polyamide 6 Viscosity number = 99 ml / g
Novamid 1007J A-2) Polyamide 6 manufactured by Mitsubishi Engineering Plastics Co., Ltd. Viscosity number = 87 ml / g
Novamid 1005J Mitsubishi Engineering Plastics A-3) Polyamide 6 Viscosity = 118ml / g
Novamid 1010J A-4) manufactured by Mitsubishi Engineering Plastics Co., Ltd. Polyamide 6 Viscosity = 150 ml / g
Novamid 1015J A-5) Polyamide 66 manufactured by Mitsubishi Engineering Plastics Co., Ltd. Viscosity = 118 ml / g
Amilan E-3000 manufactured by Toray Industries, Inc. B) Melamine cyanurate MCA-CO Mitsubishi Chemical C-1) Ground glass fiber Average length = 30 μm Fiber diameter = 10 μm Surface untreated PFE-001 Nittobo C-2) Ground Glass fiber average length = 60 μm Fiber diameter = 10 μm Surface untreated MF06JF0-20 Asahi Fiber Glass C-3) Ground glass fiber Average length = 200 μm Fiber diameter = 10 μm Surface untreated MF20JH1-20 Asahi Fiber Glass C-4 ) Crushed glass fiber Average length = 60 μm Fiber diameter = 10 μm Phosphorous acid treatment MF06JB3-20 C-5 made by Asahi Fiber Glass) Glass fiber chopped strand
Average length = 3mm Fiber diameter = 10μm
Surface aminosilane treatment, urethane sizing agent 123D10P Owens Corning D-1) Carboxylic acid amide wax release agent WH255 Kyoeisha Chemical D-2) Polyethylene wax release agent High wax 110P Mitsui Chemicals

[Examples and evaluation methods]
1) Viscosity number 1% was dissolved in 96% concentrated sulfuric acid solvent in accordance with JIS K6933-99 and measured at 23 ° C.
2) Flame retardance Using a test piece having a size of 12.7 × 127 × 0.75 mm, a 20 mm vertical combustion test was performed in accordance with the test method UL-94 standard. When the combustibility is V-2 or higher (V-2, V-1 or V-0), it is determined as “pass”.
3) GWFI
A test piece having a thickness of 1.6 mm was used, and measurement was performed in accordance with test method IEC 60695-2-12.
However, the temperature at the tip of the glow wire is fixed at 960 ° C., and all three samples pass the flammability (GWFI) acceptance criteria:
1) Combustion time after contact for 30 seconds is within 30 seconds. 2) Check whether the tissue paper under the sample does not ignite or not, and determine “Pass” when satisfied.
In addition, the size of the combustion flame was observed for reference together with the combustion time after the rod contact.
4) CTI
Measurement was performed in accordance with test method IEC 60112 using a test piece having a thickness of 3.0 mm. As a result of the tracking resistance test, when the comparative tracking index (CTI) is 500 V or more, it is determined as “pass”.

[Examples 1-5, 7-8] and [Comparative Examples 1-4]
After blending the polyamide resin and various additives at the blending ratio shown in Table-1, Table-2 or Table-3 (unit is part by weight), cylinder temperature 240 using a TEX30C type twin screw extruder manufactured by Nippon Steel Works The mixture was melt-kneaded under the conditions of 200 ° C. and a screw rotational speed of 200 rpm to obtain polyamide resin composition pellets.
Each test piece was injection-molded from the obtained pellets using a J75ED molding machine manufactured by Nippon Steel Works with a cylinder temperature set at 240 ° C and a mold temperature set at 80 ° C. The produced test pieces were evaluated for combustibility, GWFI, and CTI based on predetermined standards. The evaluation results are shown in Table-1, Table-2 or Table-3.

Moreover, the compounding prescription of Example 1 was melt-kneaded under the conditions of a cylinder temperature of 240 ° C. and a screw rotation speed of 200 rpm using a TEX30C type twin screw extruder manufactured by Nippon Steel Works to obtain a pellet of a polyamide resin composition. It was.
The obtained pellets were injection-molded with a J75ED molding machine manufactured by Nippon Steel Works with a cylinder temperature set at 240 ° C and a mold temperature set at 80 ° C, and the breaker casing parts were 80mm long x 50mm wide x 10mm high (Thickness 1.6 mm) was produced.
The resulting breaker casing component was excellent in good appearance and low warpage. Furthermore, it was confirmed that the evaluation result of CWFI (960 ° C.) based on IEC60695-2-12 was “pass” in the breaker casing part.

[Example 6]
After blending the polyamide resin and various additives in the blending ratio shown in Table-2 (unit: parts by weight), using a TEX30C twin screw extruder manufactured by Nippon Steel Works, conditions of cylinder temperature 270 ° C. and screw rotation speed 200 rpm The resulting mixture was melt-kneaded to obtain polyamide resin composition pellets.
Each test piece was injection-molded from the obtained pellets using a J75ED molding machine manufactured by Nippon Steel Works with a cylinder temperature set at 270 ° C and a mold temperature set at 80 ° C. The produced test pieces were evaluated for combustibility, GWFI, and CTI based on predetermined standards. The evaluation results are shown in Table-2.

5) Number average fiber length In addition, the number average fiber length of the glass-based filler is measured by collecting the pellets obtained in each Example and Comparative Example in a crucible and heating them in an electric furnace at 500 ° C. for 30 minutes. After complete ashing, cool, add an appropriate amount of 3% neutral detergent aqueous solution and stir with an ultrasonic cleaner for 3 minutes. Collect the resulting dispersion on a special glass plate with a glass pipette. The photo was taken using a microscope. That is, for the photographed photographic image of the glass-based filler, the maximum dimension for each of 1000 individual filler particles was measured using a digitizer, and the number average fiber length was determined. In the case of substantially spherical glass beads, the maximum diameter of each substantially spherical was measured, and the number average fiber length was determined from this.

(1) As shown in Examples 1 to 8 and Comparative Examples 1 to 4, a specific amount of glass fiber and a triazine flame retardant comprising a specific fiber length / surface treatment agent type are added to a polyamide having a specific viscosity number range. By blending, the goals of flame retardancy, GWFI, and CTI can be achieved.
(2) In comparison between Example 1 and Comparative Example 1, when the viscosity number is large, UL94 flame retardancy tends to decrease and 960 ° C. GWFI tends to fail.
(3) In comparison between Example 4 and Comparative Example 3, when the number average fiber length is large, 960 ° C. GWFI tends to be rejected.
(4) In comparison between Example 4 and Comparative Example 2, if the glass fiber length is large, the tracking resistance tends to be lowered.
(5) Comparison between Example 7 and Comparative Example 4 is influenced by GWFI and CTI depending on the type of release agent.

[Industrial applicability]
As described in detail above, the present invention can be expected to have the following advantageous effects and has an extremely high industrial utility value.
That is, since the present invention is a polyamide resin excellent in flame retardancy, glow wire characteristics, and tracking characteristics, it is suitable for use as a safety breaker or an earth leakage breaker incorporated in electric wiring.

Claims (3)

(A) In accordance with JIS K6933, 0.5% to 35% by weight of (B) triazine flame retardant with respect to 100 parts by weight of polyamide resin having a viscosity of 70 to 140 ml / g measured at a concentration of 96% sulfuric acid at 1% and a temperature of 23 ° C. And (C) 10-60 parts by weight of a glass filler not surface-treated or surface-treated with an acid compound, the glass filler is dispersed with a number average fiber length of 20-70 μm, and A polyamide resin composition for a breaker comprising the following properties:
a) When performing a 20 mm vertical combustion test according to UL 94, flame retardancy is V-2 or higher b) Performing a 960 ° C. glow wire flammability test (1.6 mm thickness) according to IEC 60695-2-12 When the tracking resistance test (3 mm thickness) is performed according to IEC 60112, the comparative tracking index (CTI) is 500 V or more.   The polyamide resin composition for a breaker according to claim 1, wherein 0.01 to 0.5 parts by weight of a bisamide-based or carboxylic acid amide-based wax is mixed with 100 parts by weight of the polyamide resin. A polyamide resin molded article for a breaker comprising the composition according to claim 1 or 2.