Insulating flame-retardant resin composition, molded article, and sheet

Abstract

The present invention provides: an insulating flame-retardant resin composition excellent in terms of flame retardancy, tracking resistance, mold releasability, and thermal stability; a molded article; and a sheet. This flame-retardant resin composition is characterized by comprising (A) 100 parts by weight of a polycarbonate resin (A component) and (B) 0.5-1.8 parts by weight of a flame retardant (B component), the flame retardant being a nitrogen-containing compound.

Description

Flame-retardant insulating resin composition, molded article, and sheet

[0001] The present invention relates to a flame-retardant insulating resin composition, a molded article, and a sheet, which are excellent in flame retardancy, tracking resistance, mold releasability, and thermal stability.

[0002] Polycarbonate resins have excellent mechanical properties and are therefore widely used in automobile peripheral components, battery peripheral components, etc. ２ To reduce CO2 emissions, the development of batteries and electric vehicles has been invigorated. From a safety perspective, there is a growing demand for materials with excellent flame retardancy and tracking resistance that can withstand high voltages. A conventional method for improving flame retardancy has been to incorporate a flame retardant into a resin molded product. For example, to improve the flame retardancy of polycarbonate resin, a method has been used in which a large amount of an oligomer or polymer of a carbonate derivative of brominated bisphenol A is incorporated. However, the addition of a large amount of flame retardant has caused many problems, such as the generation of halogenated gases that are harmful to the human body during combustion. Therefore, there is a demand for flame-retardant resin compositions that use a flame retardant that does not generate halogen-containing gases.

[0003] Patent Document 1 discloses a thermoplastic resin composition containing ammonium polyphosphate, a phosphorus-containing compound, and a nitrogen-containing cyclic compound as flame retardants. However, despite the use of large amounts of ammonium polyphosphate and a nitrogen-containing cyclic compound as flame retardants, the composition suffers from the problem of insufficient flame retardancy. Furthermore, no mention is made of tracking resistance. Patent Documents 2 and 3 disclose flame-retardant resin compositions comprising a polycarbonate resin, a low-molecular-weight phosphate ester compound as a flame retardant, and a fibrous material. However, when a low-molecular-weight phosphate ester compound such as an aromatic diphosphate is used as a flame retardant, a large amount must be added to impart flame retardancy, and char formation is also promoted, resulting in increased conductivity and poor tracking resistance.

[0004] Japanese Patent Application Laid-Open No. 2000-154322 Japanese Patent Application Laid-Open No. 2002-30209 Japanese Patent Application Laid-Open No. 2002-226694

[0005] In view of the above, an object of the present invention is to provide a flame-retardant insulating resin composition, a molded article, and a sheet which are excellent in flame retardancy, tracking resistance, mold releasability, and thermal stability.

[0006] According to the present invention, the above-mentioned problems are solved by the following configurations: 1. A flame-retardant insulating resin composition comprising 0.5 to 1.8 parts by weight of a flame retardant (B) (Component B) relative to 100 parts by weight of an (A) polycarbonate resin (Component A), wherein the flame retardant is a nitrogen-containing compound. 2. The flame-retardant insulating resin composition according to item 1 above, wherein the nitrogen-containing compound is melamine cyanurate. 3. The flame-retardant insulating resin composition according to item 1 or 2 above, wherein the flame-retardant insulating resin composition comprises 0.05 to 1.8 parts by weight of carbon black (Component C) relative to 100 parts by weight of Component A. 4. The flame-retardant insulating resin composition according to any one of items 1 to 3 above, wherein Component A has a viscosity-average molecular weight of 17,000 to 25,500. 5. The flame-retardant insulating resin composition according to any one of items 1 to 4 above, wherein Component B is a nitrogen-containing compound in which the proportion of particles having a particle size of 50 μm or more, as measured by the Microtrack method, is less than 0.1%. 6. A molded article or sheet obtained by molding the flame-retardant insulating resin composition according to any one of items 1 to 5 above.

[0007] The flame-retardant insulating resin composition of the present invention is excellent in flame retardancy, tracking resistance, mold releasability, and thermal stability, and is therefore widely useful in electrical and electronic applications, automotive peripheral parts, battery peripheral parts, and various other applications. In particular, the present invention provides molded articles that are extremely useful in electrical and electronic applications, automotive peripheral parts, and battery peripheral parts, and the industrial effects of the present invention are extremely great.

[0008] The present invention will be further described in detail below.

[0009] <Component A: Polycarbonate Resin> The polycarbonate resin used in the present invention is obtained by reacting a dihydric phenol with a carbonate precursor. Examples of the reaction method include interfacial polycondensation, melt transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds.

[0010] Representative examples of the dihydric phenol used herein include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)methane, bis{(4-hydroxy-3,5-dimethyl)phenyl}methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, 2,2-bis{(4- 2,2-bis{(3-isopropyl-4-hydroxy)phenyl}propane, 2,2-bis{(4-hydroxy-3-phenyl)phenyl}propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis{(4-hydroxy-3-methyl)phenyl}fluorene, α,α'-bis(4-hydroxyphenyl)-o-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene Examples of the dihydroxydiphenyl ether include 4,4'-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-p-diisopropylbenzene, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenyl ester, and these can be used alone or in combination of two or more.

[0011] Among these, homopolymers or copolymers obtained from at least one bisphenol selected from the group consisting of bisphenol A, 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, and α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene are preferred, and homopolymers of bisphenol A and copolymers of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane with bisphenol A, 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, or α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene are particularly preferred.

[0012] Carbonate precursors that can be used include carbonyl halides, carbonate esters, and haloformates, and specific examples include phosgene, diphenyl carbonate, and dihaloformates of dihydric phenols.

[0013] When the dihydric phenol and the carbonate precursor are reacted by the interfacial polycondensation method or the melt transesterification method to produce the polycarbonate resin, a catalyst, a terminal terminator, an antioxidant for the dihydric phenol, etc. may be used as necessary. The polycarbonate resin may be a branched polycarbonate resin copolymerized with a trifunctional or higher polyfunctional aromatic compound, or a polyester carbonate resin copolymerized with an aromatic or aliphatic bifunctional carboxylic acid, or a mixture of two or more of the obtained polycarbonate resins.

[0014] The reaction modes of the methods for producing the polycarbonate resin of the present invention, such as interfacial polymerization, melt transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds, are well known in various literatures and patent publications.

[0015] If the viscosity average molecular weight of the polycarbonate resin is less than 17,000, cracking may occur during molding, and if it exceeds 25,500, fluidity may deteriorate and moldability may decrease. Therefore, the viscosity average molecular weight is preferably 17,000 to 25,500, more preferably 17,000 to 25,400, and even more preferably 17,300 to 25,000.

[0016] Two or more types of polycarbonate resins may be mixed together, and in this case, it is of course possible to mix a polycarbonate resin having a viscosity average molecular weight outside the above range.

[0017] The viscosity average molecular weight referred to in the present invention is the specific viscosity (η) determined from a solution prepared by dissolving 0.7 g of polycarbonate resin in 100 ml of methylene chloride at 20°C. ＳＰ ) into the following equation: η ＳＰ / c = [η] + 0.45 × [η] ２ c (where [η] is the intrinsic viscosity) [η] = 1.23 × 10 －４ M ０.８３ c=0.7

[0018] <Component B: Flame Retardant> The flame retardant used as component B of the present invention is a nitrogen-containing compound, preferably melamine cyanurate. Specific examples of melamine cyanurate include MC25 (manufactured by BASF, D50: 1.5 μm, D99: 11.6 μm), MC6000 (manufactured by Nissan Chemical Industries, D50: 1.8 μm, D99: 8.3 μm), MC4000 (manufactured by Nissan Chemical Industries, D50: 14.1 μm, D99: 58.8 μm), MC7000 (manufactured by Nissan Chemical Industries, D50: 1.9 μm, D99: 3.0 μm), MC-20S (manufactured by Sakai Chemical Industry Co., Ltd., D50: 3.2 μm, D99: 10.1 μm), and MC-2010N (manufactured by Sakai Chemical Industry Co., Ltd., D50: 3.1 μm, D99: 9.9 μm). D50 and D99 were measured by laser analysis / scattering using a SALD-3000S manufactured by Shimadzu Corporation. D99 is preferably 1 μm to 10 μm, more preferably 3 μm to 9 μm, and even more preferably 5 μm to 9 μm. When D99 is within this range, a better balance of flame retardancy, tracking resistance, and sheet mass productivity may be achieved. These compounds can be used alone or in combination with other flame retardants. When a flame retardant other than a nitrogen-containing compound is used as a flame retardant, it becomes difficult to achieve both flame retardancy and tracking resistance.

[0019] Component B is preferably a nitrogen-containing compound in which the proportion of particles having a particle size of 50 μm or more as measured by the Microtrack method is less than 0.1%, and more preferably less than 0.05%. If the proportion is less than 0.1%, the proportion of small particles will be high, and flame retardancy can be efficiently achieved with a small amount. The lower limit of the proportion is preferably 0%.

[0020] The content of Component B is 0.5 to 1.8 parts by weight, preferably 0.55 to 1.79 parts by weight, more preferably 0.6 to 1.78 parts by weight, and even more preferably 0.6 to 1.3 parts by weight, per 100 parts by weight of Component A. If the content of Component B is less than 0.5 parts by weight, flame retardancy will deteriorate, and if it exceeds 1.8 parts by weight, flame retardancy and thermal stability will deteriorate.

[0021] <Component C: Carbon Black> The method for adding the carbon black used in the present invention is not particularly limited, but from the viewpoint of workability, it is preferable to use a master made by kneading the carbon black with the polycarbonate resin in advance. The kneading method is not particularly limited, but kneading with an extruder is preferred.

[0022] The content of Component C is preferably 0.05 to 1.8 parts by weight, more preferably 0.06 to 1.79 parts by weight, even more preferably 0.07 to 1.78 parts by weight, particularly preferably 0.08 to 1.77 parts by weight, and most preferably 0.08 to 1.6 parts by weight, relative to 100 parts by weight of Component A. If the content of Component C is less than 0.05 parts by weight, it may not be possible to impart hiding properties to the molded article, whereas if it exceeds 1.8 parts by weight, electrical conductivity may increase, resulting in poor tracking resistance.

[0023] <Regarding the Production Method of the Flame-Retardant Insulating Resin Composition> The flame-retardant insulating resin composition of the present invention can be produced by any method. For example, it can be produced by kneading using a single-screw or multi-screw extruder or the like. It can be prepared by feeding the polycarbonate resin (Component A), the flame retardant (Component B), and optionally other components into the extruder using a feeder. The flame-retardant insulating resin composition thus obtained can be made into molded articles or sheets for use in automotive parts, battery peripheral parts, etc., using various known methods, such as injection molding and sheet molding.

[0024] The flame-retardant insulating resin composition of the present invention will be specifically described below with reference to examples. In the following measurement conditions and examples, "parts" respectively represent "parts by weight."

[0025] <Materials Used> <Component A: Polycarbonate Resin> A-1: ​​L-1250WQ (trade name) (manufactured by Teijin Limited, viscosity average molecular weight 25,100) A-2: L-1250WP (trade name) (manufactured by Teijin Limited, viscosity average molecular weight 23,800) A-3: L-1225WX (trade name) (manufactured by Teijin Limited, viscosity average molecular weight 19,700) <Component B: Flame Retardant> B-1: MC25 (trade name) (manufactured by BASF, melamine cyanurate, D50: 1.5 μm, D99: 11.6 μm, proportion of particles having a particle size of 50 μm or more as measured by the Microtrac method is less than 0.1%) B-2 (Comparative Example): PX-200 (trade name) (manufactured by Daihachi Chemical Industry Co., Ltd., condensed phosphorus ester) B-3: MC6000 (trade name) (manufactured by Nissan Chemical Industries, Ltd., melamine cyanurate, D50: 1.8 μm, D99: 8.3 μm, proportion of particles having a particle size of 50 μm or more as measured by the Microtrack method is less than 0.1%) B-4: MC7000 (trade name) (manufactured by Nissan Chemical Industries, Ltd., melamine cyanurate, D50: 1.9 μm, D99: 3.0 μm, proportion of particles having a particle size of 50 μm or more as measured by the Microtrack method is less than 0.1%) <Component C: Carbon black> C-1: 650B (trade name) (manufactured by Mitsubishi Chemical Corporation, particle size 22 nm)

[0026] <Production of insulating flame-retardant resin composition> (Examples 1 to 9, Comparative Examples 1 to 3) The components shown in Table 1 were premixed in the ratios shown in Table 1, and each was melt-kneaded at 250°C using a twin-screw extruder [TEX30α-3, manufactured by The Japan Steel Works, Ltd.], and pellets were produced while degassing using a vacuum vent.

[0027] The pellets were dried at 120° C. for 5 hours or more in a hot air circulation dryer, and then test pieces were prepared and evaluated according to the following evaluation methods. The results are shown in Table 2.

[0028] 1. Flame Retardancy Using an injection molding machine [NEX50-5E, manufactured by Nissei Plastic Industrial Co., Ltd.], 0.3 mmt test pieces (125 mm x 13 mm x 0.3 mmt) were prepared under conditions of a cylinder temperature of 280°C, a mold temperature of 80°C, and an injection speed of 270 mm / sec. The test pieces were then conditioned for 48 hours at 23°C x 50% humidity, and the flame retardancy was evaluated in accordance with the UL94 test (flammability test for plastic materials for equipment components). A V-0 rating was considered pass, and any other rating was considered fail. The UL94 classification is shown in Table 1.

[0029]

[0030] 2. Tracking Resistance Tracking resistance was evaluated by the following method. It is necessary to pass Tracking Resistance I, and it is preferable to pass Tracking Resistance II. 1) Tracking Resistance I Two 2 mmt test pieces (50 mm x 90 mm x 2 mmt) were molded using an injection molding machine [ROBOSHOT α-S100iA, manufactured by FANUC] at a cylinder temperature of 260°C and a mold temperature of 65°C. A voltage of 600 V was applied to these pieces using a tracking resistance tester [YST-112, manufactured by Yamayo Testing Instruments], and a 0.1% aqueous solution of ammonium chloride was dropped every 30 seconds. If no tracking occurred for 100 drops, the test was considered to have passed, and if tracking occurred, the test was considered to have failed. 2) Tracking Resistance II: 3 mm test pieces (50 mm x 90 mm x 3 mm) molded using an injection molding machine [ROBOSHOT α-S100iA, manufactured by FANUC] at a cylinder temperature of 260°C and a mold temperature of 65°C were measured using a tracking resistance tester [YST-112, manufactured by Yamayo Testing Instruments] in accordance with ASTM D3638:2021. That is, voltages of 300 V to 600 V were applied in 25 V intervals, and a 0.1% aqueous solution of ammonium chloride was dripped every 30 seconds at each voltage. The applied voltage at which tracking did not occur for 50 or more drops was calculated. A voltage of 600 V at which tracking did not occur was deemed a pass, and a voltage below 600 V was deemed a fail.

[0031] 3. Mold releasability Using an injection molding machine [ROBOSHOT α-S100iA manufactured by FANUC], 2 mmt test pieces (50 mm x 90 mm x 2 mmt) were molded at a cylinder temperature of 260°C and a mold temperature of 65°C. When no cracks occurred in the molded product or sprue upon mold release, the result was rated as ◯, and when cracks occurred or mold release was difficult, the result was rated as ×.

[0032] 4. Thermal Stability Using an injection molding machine [ROBOSHOT α-S100iA manufactured by FANUC], the product was held at a cylinder temperature of 260°C and a mold temperature of 60°C for 10 minutes, after which five 2mmt test pieces (50mm x 90mm x 2mmt) were molded. The five pieces were visually inspected for silver spots and rated according to the following criteria: ○: The number of pieces with silver spots was two or less and the area of ​​silver spots on all molded pieces was 200mm ２ Less than ×: The number of sheets with silver spots is 3 or more, or the area of ​​silver spots on any of the molded products is 200 mm ２ End

[0033]

[0034] As shown in Table 2, the present invention can provide a flame-retardant insulating resin composition that is excellent in flame retardancy, tracking resistance, mold releasability, and thermal stability.

[0035] Molded articles and sheets made from the flame-retardant insulating resin composition of the present invention can be used in a variety of applications, including automobile peripheral parts and battery peripheral members.

Claims

1. An insulating flame-retardant resin composition comprising 100 parts by weight of (A) polycarbonate resin (component A) and 0.5 to 1.8 parts by weight of (B) flame retardant (component B), wherein the flame retardant is a nitrogen-containing compound.

2. The insulating flame-retardant resin composition according to claim 1, wherein the nitrogen-containing compound is melamine cyanurate.

3. The insulating flame-retardant resin composition according to claim 1 or 2, characterized in that it contains 0.05 to 1.8 parts by weight of (C) carbon black (component C) per 100 parts by weight of component A.

4. The insulating flame-retardant resin composition according to claim 1 or 2, wherein the viscosity average molecular weight of component A is 17,000 to 25,500.

5. An insulating flame-retardant resin composition according to claim 1 or 2, characterized in that component B is a nitrogen-containing compound in which the proportion of particles having a particle size of 50 μm or more as measured by the Microtrack method is less than 0.1%.

6. A molded article or sheet obtained by molding the insulating flame-retardant resin composition according to claim 1 or 2.

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