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

Abstract

To provide a flame-retardant polycarbonate resin composition excellent in flame retardancy and thermal stability, and to provide a molded article and a sheet.SOLUTION: A flame-retardant polycarbonate resin composition comprising 2 to 10 parts by weight of (B) a nitrogen-containing compound (component B) based on 100 parts by weight of (A) a polycarbonate resin (component A), wherein when a surface of a molded article of the resin composition is observed with a microscope at a magnification of 150 times, the number of aggregates having a particle diameter of 100 μm or more in 100 aggregates derived from the nitrogen-containing compound is less than 10.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a flame-retardant polycarbonate resin composition having excellent flame retardancy and thermal stability, as well as a molded article and a sheet. [Background technology]

[0002] Polycarbonate resin, with its excellent transparency, impact resistance, heat resistance, and dimensional stability, is used as an engineering plastic in a wide range of applications, including electrical and electronic device housings, automotive interior and exterior components, building materials, furniture, musical instruments, and miscellaneous goods. In recent years, the miniaturization of devices has led to the thinning of product components, increasing the demand for thin-wall flame retardancy. To achieve thin-wall flame retardancy, plastic flame retardants are typically used. However, while plastic flame retardants can achieve thin-wall flame retardancy, they struggle to achieve thick-wall flame retardancy. Therefore, flame retardants that offer both thin-wall and thick-wall flame retardancy are needed. Furthermore, a traditional method for improving flame retardancy has been to incorporate flame retardants into molded resin products. For example, the incorporation of large amounts of oligomers or polymers of carbonate derivatives of brominated bisphenol A has been used to improve the flame retardancy of polycarbonate resin. However, the addition of large amounts of flame retardants has presented numerous problems, including the generation of halogenated gases harmful to humans during combustion. Therefore, there is a demand for flame-retardant resin compositions that use flame retardants that do 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 flame retardancy is insufficient, and there is no mention of flame retardancy for thicker walls. Patent Documents 2 and 3 disclose flame-retardant resin compositions consisting of 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 there is no mention of flame retardancy for thicker walls. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-154322 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-30209 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-226694 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, an object of the present invention is to provide a flame-retardant polycarbonate resin composition having excellent flame retardancy and thermal stability, as well as a molded article and a sheet. [Means for solving the problem]

[0006] According to the present invention, the above problems are solved by the following configuration. 1. A resin composition comprising 2 to 10 parts by weight of a nitrogen-containing compound (component B) with respect to 100 parts by weight of a polycarbonate resin (component A), wherein when the surface of a molded article of the resin composition is observed at a magnification of 150 times using a microscope, the number of aggregates having a particle diameter of 100 μm or more among 100 aggregates caused by the nitrogen-containing compound is less than 10. A flame-retardant polycarbonate resin composition characterized by this. 2. The resin composition according to item 1 above, characterized in that component B is melamine cyanurate. 3. The resin composition according to item 1 or 2 above, characterized in that component B is a nitrogen-containing compound having a particle diameter D90 measured by the microtrack method of 4 μm or less. 4. The resin composition according to any one of items 1 to 3 above, characterized in that component A is in powder form. 5. A molded article or sheet formed by molding the resin composition according to any one of items 1 to 4 above.

Effect of the Invention

[0007] The flame-retardant polycarbonate resin composition of the present invention is excellent in flame retardancy and thermal stability in a wide thickness range, and thus is widely useful in various applications such as electrical and electronic applications, automotive peripheral component applications, battery peripheral component applications, and other various applications. Among them, it provides a molded article that is extremely useful as an electrical and electronic application, an automotive peripheral component application, and a battery peripheral component application, and the industrial effect achieved by the present invention is extremely large.

Modes for Carrying Out the Invention

[0008] Hereinafter, the details of the present invention will be further described.

[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 the interfacial polycondensation method, the melt transesterification method, the solid-phase transesterification method of a carbonate prepolymer, and the ring-opening polymerization method of a cyclic carbonate compound.

[0010] Representative examples of dihydric phenols 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'-isopropylbenzene, 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 producing a polycarbonate resin by reacting the dihydric phenol with a carbonate precursor by the interfacial polycondensation method or the melt transesterification method, 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] Reaction methods such as the interfacial polymerization method, melt transesterification method, solid-phase transesterification method of carbonate prepolymer, and ring-opening polymerization method of cyclic carbonate compound for the production method of the polycarbonate resin of the present invention are methods well-known in various documents and patent gazettes.

[0015] When the viscosity-average molecular weight of the polycarbonate resin is less than 17,000, cracks may occur during molding. When it exceeds 25,500, the fluidity deteriorates and the molding processability may decrease. Therefore, it 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 polycarbonate resins may be mixed. In this case, it is of course possible to mix a polycarbonate resin whose viscosity-average molecular weight is outside the above range.

[0017] The viscosity-average molecular weight referred to in the present invention is the specific viscosity (η

[0018] ) obtained from a solution prepared by dissolving 0.7 g of polycarbonate resin in 100 ml of methylene chloride at 20°C and is calculated by inserting it into the following formula. 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 Also, the polycarbonate resin is preferably in powder form. By using a polycarbonate resin in powder form, the dispersibility of the nitrogen-containing compound in the molded product can be improved, and a resin composition excellent in flame retardancy may be produced. When a polycarbonate resin other than powder form (for example, pellet form) is used, the dispersibility of the nitrogen-containing compound may be inferior and the flame retardancy may decrease.

[0018] <Component B: Nitrogen-containing compound> The nitrogen-containing compound used as component B of the present invention is preferably melamine cyanurate. Specific examples of melamine cyanurate include MC7000 (manufactured by Nissan Chemical Industries, Ltd., average particle size: 1.066 μm, particle size D90: 2.85 μm). This compound can be used alone or in combination with other flame retardants. When a flame retardant other than a nitrogen-containing compound is used as the flame retardant, thin-wall flame retardancy deteriorates.

[0019] Component B is preferably a nitrogen-containing compound having a particle size D90 of 4 μm or less as measured by the Microtrack method. The particle size D90 is more preferably 3.5 μm or less, and even more preferably 3 μm or less. When the particle size D90 is 4 μm or less, the dispersibility of the nitrogen-containing compound in the molded article is improved, and flame retardancy may be efficiently exhibited. The lower limit of the particle size D90 is not particularly limited, but is preferably 2 μm.

[0020] The content of Component B is 2 to 10 parts by weight, preferably 2.5 to 9.5 parts by weight, and more preferably 3 to 9 parts by weight, per 100 parts by weight of Component A. If the content of Component B is less than 2 parts by weight, the flame retardancy will deteriorate, and if it exceeds 10 parts by weight, the flame retardancy and thermal stability will deteriorate.

[0021] <Other additives> The flame-retardant polycarbonate resin composition of the present invention may contain a mold release agent for improving moldability and various stabilizers for preventing a decrease in molecular weight during molding and for stabilizing color tone.

[0022] (i) Mold release agent The flame-retardant polycarbonate resin composition of the present invention may further contain known release agents such as fatty acid esters, polyolefin waxes, silicone compounds, fluorine compounds (such as fluorinated oils typified by polyfluoroalkyl ethers), paraffin wax, and beeswax, in order to improve productivity during molding and the dimensional accuracy of molded articles. The content of the release agent is preferably 0.05 to 0.5 parts by weight, and more preferably 0.1 to 0.4 parts by weight, per 100 parts by weight of Component A. If the content of the release agent is less than 0.05 parts by weight, the release properties may be poor, and if it exceeds 0.5 parts by weight, the mechanical properties and flame retardancy may deteriorate.

[0023] (ii) Stabilizers The flame-retardant polycarbonate resin composition of the present invention can be blended with various known stabilizers. Examples of stabilizers include phosphorus-based stabilizers, hindered phenol-based antioxidants, ultraviolet absorbers, and light stabilizers. The stabilizer content is preferably 0.001 to 1 part by weight, and more preferably 0.01 to 0.8 parts by weight, per 100 parts by weight of Component A. If the release agent content is less than 0.001 part by weight, the effect on thermal stabilization of the polycarbonate resin may be low, resulting in poor thermal stability. If the content exceeds 1 part by weight, mechanical properties and flame retardancy may deteriorate.

[0024] <Method for producing flame-retardant polycarbonate resin composition> The flame-retardant polycarbonate resin composition of the present invention can be produced by any method. For example, it can be produced by kneading in a single-screw or multi-screw extruder. 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 polycarbonate 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.

[0025] <Dispersibility of nitrogen-containing compounds> The flame-retardant polycarbonate resin composition of the present invention requires that when the surface of a molded product of the resin composition is observed at a magnification of 150 times using a microscope, the number of aggregates with a particle diameter of 100 μm or more among 100 aggregates caused by nitrogen-containing compounds is less than 10. The number of aggregates is preferably less than 8, and more preferably less than 6. When the number of aggregates is 10 or more, the flame retardancy is poor. Although the lower limit of the number of aggregates is not particularly limited, it is preferably 5.

Examples

[0026] Hereinafter, the flame-retardant polycarbonate resin composition of the present invention will be specifically described based on examples. "Parts" in the following measurement conditions and examples etc. each represent "parts by weight". <Materials Used> <Component A: Polycarbonate Resin> A-1: L-1250WP (trade name) (manufactured by Teijin Limited, powder shape, viscosity average molecular weight 23,900) A-2: L-1225WX (trade name) (manufactured by Teijin Limited, powder shape, viscosity average molecular weight 19,700) A-3 (comparative example): L-1225L (trade name) (manufactured by Teijin Limited, pellet shape, viscosity average molecular weight 19,700) A-4 (comparative example): PC-116A (trade name) (manufactured by Fenghua Hongyu Plastics Co., Ltd., pellet shape, viscosity average molecular weight 20,700) <Component B: Flame Retardant> B-1: MC7000 (trade name) (manufactured by Nissan Chemical Industries, melamine cyanurate, particle D90 = 2.85 μm) B-2 (comparative example): MC6000 (trade name) (manufactured by Nissan Chemical Industries, melamine cyanurate, particle D90 = 4.77 μm) B-3 (comparative example): MC25 (trade name) (manufactured by BASF, melamine cyanurate, particle D90 = 5.47 μm) <Other Components> C-1: S-100A (trade name) (release agent, manufactured by Riken Vitamin Co., Ltd., glycerin monostearate) D-1: AO-50 (trade name) (stabilizer, manufactured by ADEKA, phenolic antioxidant)

[0027] (Examples 1 to 7, Comparative Examples 1 to 5) <Production of Flame-Retardant Polycarbonate Resin Composition> The components shown in Table 2 were mixed in the ratios shown in Table 2, melt-kneaded at 250°C using a twin-screw extruder [TEX30α-3, manufactured by The Japan Steel Works], and pellets were produced while degassing using a vacuum vent.

[0028] <Evaluation method> The pellets were dried in a hot air circulation dryer at 120°C for 5 hours or more, and then test pieces were prepared and evaluated according to the following evaluation methods. The results are shown in Table 2. 1. Number of aggregates caused by nitrogen-containing compounds Using an injection molding machine [ROBOSHOT α-S100iA, manufactured by Fanuc], a cylinder temperature of 250°C and a mold temperature of 80°C were used to mold 2mm-thick test pieces (50mm x 90mm x 2mmt). The surfaces of the molded pieces were observed at 150x magnification using a microscope [VHX-8000, manufactured by Keyence]. One hundred aggregates caused by nitrogen-containing compounds were randomly selected from those observed on the surface, and aggregates with a particle diameter of 100μm or more were counted. Furthermore, nitrogen peaks were detected using EDS to identify the counted particles as nitrogen-containing compounds. 2.Flame retardant Using an injection molding machine [NEX50-5E, manufactured by Nissei Plastic Industrial Co., Ltd.], 0.4 mm thick test pieces (125 mm x 13 mm x 0.4 mm thick) and 2.0 mm thick test pieces (125 mm x 13 mm x 2.0 mm thick) 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 and 50% humidity. Flame retardancy was evaluated according to UL94 (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] [Table 1]

[0030] 3.Thermal stability Using an injection molding machine [ROBOSHOT α-S100iA manufactured by FANUC], the sample was left to dwell for 10 minutes at a cylinder temperature of 250°C and a mold temperature of 80°C, after which five 2mm thick test pieces (50mm x 90mm x 2mmt) were molded. The silver in each of the five pieces was visually inspected and judged according to the following criteria. ○: The number of sheets with silver spots is 2 or less and the area of ​​silver spots on the surface of each molded product is 20 mm 2 less than ×: The number of sheets with silver spots is 3 or more, or the area of ​​silver spots on the surface of each molded product is 200mm 2 End

[0031] [Table 2]

[0032] As shown in Table 2, the present invention can provide a flame-retardant polycarbonate resin composition that is excellent in thin-wall flame retardancy, thick-wall flame retardancy, and thermal stability. [Industrial Applicability]

[0033] Molded articles and sheets made from the flame-retardant polycarbonate resin composition of the present invention can be used in a variety of applications, including automobile peripheral parts and battery peripheral members.

Claims

1. A flame-retardant polycarbonate resin composition comprising 2 to 10 parts by weight of (B) a nitrogen-containing compound (component B) per 100 parts by weight of (A) a polycarbonate resin (component A), wherein when the surface of a molded article of the resin composition is observed using a microscope at a magnification of 150 times, the number of aggregates having a particle size of 100 μm or more out of 100 aggregates caused by the nitrogen-containing compound is less than 10.

2. 2. The resin composition according to claim 1, wherein component B is melamine cyanurate.

3. 3. The resin composition according to claim 1, wherein component B is a nitrogen-containing compound having a particle diameter D90 of 4 μm or less as measured by a microtrack method.

4. 3. The resin composition according to claim 1, wherein component A is in powder form.

5. A molded article or sheet obtained by molding the resin composition according to claim 1 or 2.

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