Laser weldable flame-retardant polyester resin composition and molded article comprising same

Abstract

The present invention relates to a flame-retardant polyester resin composition capable of laser welding and a molded article comprising the same, and more particularly, to a flame-retardant polyester resin composition capable of laser welding and a molded article comprising the same, and more particularly, to a flame-retardant polyester resin composition capable of laser welding and a molded article comprising the same, the present invention relates to a polyester resin composition and a molded article comprising the same, and more particularly, to a polyester resin composition and a molded article comprising the same, and more particularly, to a polyester resin composition and a molded article comprising the same, the polyester resin composition comprising a polycarbonate (PC), a polysiloxane-polycarbonate (Si-PC) copolymer, or a mixture thereof, and a flame retardant, thereby having high laser transmittance and little variation in transmittance according to injection conditions, exhibiting excellent laser weldability, while having excellent mechanical properties and flame retardancy.

Description

Technical Field

[0001] The present invention relates to a flame-retardant polyester resin composition capable of laser welding and a molded article comprising the same. More specifically, the present invention relates to a polyester resin composition comprising polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) in a specific mixing weight ratio and additionally comprising polycarbonate (PC), a polysiloxane-polycarbonate (Si-PC) copolymer, or a mixture thereof, and a flame retardant. The composition exhibits high laser transmittance, small transmittance deviation depending on injection conditions, excellent laser weldability, and excellent mechanical properties and flame retardancy, and a molded article comprising the same. Background Art

[0002] Polybutylene terephthalate (PBT), a polyester-based resin, is an engineering plastic with high crystallinity, excellent mechanical properties and heat resistance, and exceptional dimensional stability against temperature fluctuations. PBT boasts relatively low volume resistivity among engineering plastics, and due to its low water absorption, it exhibits excellent electrical properties such as electrical insulation, arc resistance, and dielectric breakdown strength. Furthermore, its high crystallization temperature during injection molding shortens cooling time, enabling high production volumes in a short period of time. These characteristics have led to its widespread use in electrical and electronic products and automotive interior and exterior parts.

[0003] In particular, recently, due to the electrification of vehicles and environmental regulations, the number of automotive electronic components that require halogen-free flame retardant properties and require laser welding has increased significantly. Laser welding of thermoplastic resins refers to a technology that uses a laser beam as an energy source to join two thermoplastic resin compositions in contact with each other, wherein the irradiated laser beam passes through a thermoplastic resin composition called a transmission layer, is absorbed by the surface of the thermoplastic resin composition in contact with the transmission layer, and is converted into heat energy. At this time, when the contact surface temperature of the two thermoplastic resin compositions rises above the melting point of the two resins, the resins will melt. After a certain period of laser beam irradiation, it stops, the molten resin solidifies again, and the transmission layer and the absorption layer will join together. Compared with other existing fastening methods, this laser welding technology has the effects of shortening process time, reducing labor, and improving productivity, and the joint surface can be completely sealed, which can protect internal components from contamination caused by external moisture, etc.

[0004] However, resin compositions containing PBT and flame retardants suffer from a problem with decreased laser transmittance due to the rapid crystallization of the PBT and the flame retardant. While this crystallization can be controlled by alloying polyethylene terephthalate (PET) with PBT, the addition of flame retardants, the degree of crystallization during injection, and variations in mold temperature can cause variations in laser transmittance, leading to poor welding.

[0005] Therefore, the preparation of a resin composition containing crystalline PBT and a flame retardant that can be laser welded remains a challenge. It is necessary to develop a material that does not deviate from the laser transmittance even when the size or thickness of the molded product changes, resulting in changes in the mold temperature, while also achieving flame retardant properties. Summary of the Invention

[0006] (1) Technical issues to be resolved

[0007] The present invention aims to provide a polyester resin composition and a molded article containing the same, wherein the composition contains PBT and a flame retardant, has high laser transmittance, has small transmittance deviation depending on injection conditions, exhibits excellent laser weldability, and also has excellent mechanical properties and flame retardancy.

[0008] (2) Technical solution

[0009] To solve the above technical problems, the present invention provides a polyester resin composition comprising: (A) polybutylene terephthalate (PBT); (B) polyethylene terephthalate (PET); (C) polycarbonate (PC), a polysiloxane-polycarbonate (Si-PC) copolymer, or a mixture thereof; and (D) a flame retardant, wherein the PBT is included in an amount of more than 1 part by weight and less than 3.2 parts by weight relative to 1 part by weight of the PET, and the laser transmittance exceeds 18%.

[0010] According to another aspect of the present invention, there is provided a molded article comprising the polyester resin composition of the present invention.

[0011] (3) Beneficial effects

[0012] According to the present invention, a polyester resin composition and a molded article containing the same can be obtained. The polyester resin composition has a laser transmittance of higher than 18% in the 980nm wavelength band, making it suitable for use as a transmission layer material for laser welding (fusion bonding). During the injection process, the laser transmittance deviation depending on the mold temperature is reduced to less than 5, and the stability is greatly improved, which can significantly reduce the defective rate during laser welding. At the same time, the polyester resin composition meets the UL94 1.5mm V-0 flame retardant rating, thereby achieving excellent flame retardancy. It also excels in mechanical properties such as tensile strength and impact strength, as well as heat resistance. DETAILED DESCRIPTION

[0013] The present invention is described in detail below.

[0014] The polyester resin composition of the present invention comprises: (A) polybutylene terephthalate (PBT); (B) polyethylene terephthalate (PET); (C) polycarbonate (PC), a polysiloxane-polycarbonate (Si-PC) copolymer, or a mixture thereof; and (D) a flame retardant, wherein the PBT is contained in an amount of more than 1 part by weight and less than 3.2 parts by weight relative to 1 part by weight of the PET.

[0015] In the polyester resin composition of the present invention, when the content ratio of the PBT is less than 1 part by weight relative to 1 part by weight of the PET, the tensile strength and heat resistance of the composition may deteriorate. When the content ratio is greater than 3.2 parts by weight, the impact strength and laser transmittance of the composition may deteriorate, and the laser transmittance deviation may also increase.

[0016] More specifically, in the polyester resin composition of the present invention, the content ratio of the PBT relative to 1 part by weight of the PET may be more than 1 part by weight, 1.01 parts by weight or more, 1.05 parts by weight or more, 1.1 parts by weight or more, 1.15 parts by weight or more, or 1.2 parts by weight or more, or less than 3.2 parts by weight, 3.15 parts by weight or less, 3.1 parts by weight or less, 3 parts by weight or less, 2.9 parts by weight or less, 2.8 parts by weight or less, 2.7 parts by weight or less, 2.6 parts by weight or less, 2.5 parts by weight or less, 2.4 parts by weight or less, or 2.33 parts by weight or less, but is not particularly limited thereto.

[0017] (A) Polybutylene terephthalate (PBT)

[0018] The polyester resin composition of the present invention contains polybutylene terephthalate.

[0019] Polybutylene terephthalate has a repeating unit shown in the following chemical formula 1, and its melting temperature is 215-235°C:

[0020] [Chemical Formula 1]

[0021]

[0022] In the chemical formula 1, n is an integer greater than or equal to 1, and specifically an integer from 50 to 200.

[0023] In a specific embodiment, considering the processability and mechanical physical properties of the composition, the polybutylene terephthalate can use polybutylene terephthalate having an intrinsic viscosity (IV) of 0.7-1.5 dl / g, more specifically polybutylene terephthalate having an IV of 0.8-1.3 dl / g or 1.1-1.3 dl / g, and can use polybutylene terephthalate having a crystallization temperature of 160-200°C, more specifically polybutylene terephthalate having a crystallization temperature of 170-190°C, but is not limited thereto.

[0024] In one specific embodiment, the polyester resin composition of the present invention may include polybutylene terephthalate in an amount ranging from greater than 23 parts by weight to less than 40 parts by weight, based on 100 parts by weight of the total composition. If the polybutylene terephthalate content is less than 23 parts by weight per 100 parts by weight of the total composition, slow curing and prolonged cycle time may occur during injection molding of the composition. If the content is greater than 40 parts by weight, the laser transmittance of the composition may decrease.

[0025] More specifically, within 100 parts by weight of the total polyester resin composition of the present invention, the polybutylene terephthalate may be included in an amount of, for example, more than 23 parts by weight, 23.1 parts by weight or more, 23.5 parts by weight or more, 24 parts by weight or more, 24.1 parts by weight or more, 24.5 parts by weight or more, or less than 40 parts by weight, 39.9 parts by weight or less, 39 parts by weight or less, 38 parts by weight or less, 37 parts by weight or less, 36 parts by weight or less, or 35 parts by weight or less, but is not particularly limited thereto.

[0026] (B) Polyethylene terephthalate (PET)

[0027] The polyester resin composition of the present invention further comprises polyethylene terephthalate.

[0028] Polyethylene terephthalate has a repeating unit shown in the following chemical formula 2, and its melting temperature is 255-265°C:

[0029] [Chemical Formula 2]

[0030]

[0031] In the chemical formula 2, n is an integer greater than or equal to 1, and specifically an integer from 40 to 160.

[0032] In a specific embodiment, considering the processability and mechanical physical properties of the composition, the polyethylene terephthalate can use polyethylene terephthalate having an intrinsic viscosity (IV) of 0.5-1.0 dl / g, more specifically polyethylene terephthalate having an IV of 0.5-0.8 dl / g or 0.65-0.8 dl / g, and can use polyethylene terephthalate having a crystallization temperature of 160-200°C, more specifically 170 to 190°C, but is not limited thereto.

[0033] In one specific embodiment, the polyester resin composition of the present invention may include polyethylene terephthalate in an amount ranging from greater than 10 parts by weight to less than 22 parts by weight, based on 100 parts by weight of the total composition. If the polyethylene terephthalate content is less than 10 parts by weight, the laser transmittance of the composition may decrease. If the content is greater than 22 parts by weight, the curing speed may be slow and the cycle time may be prolonged during injection molding of the composition.

[0034] More specifically, within 100 parts by weight of the total polyester resin composition of the present invention, the polyethylene terephthalate may be included in an amount of, for example, more than 10 parts by weight, 10.1 parts by weight or more, 10.5 parts by weight or more, 11 parts by weight or more, 11.5 parts by weight or more, or less than 22 parts by weight, 21.9 parts by weight or less, 21.5 parts by weight or less, or 21 parts by weight or less, but is not particularly limited thereto.

[0035] (C) Polycarbonate (PC), polysiloxane-polycarbonate (Si-PC) copolymer or their mixture

[0036] The polyester resin composition of the present invention further comprises polycarbonate (PC), polysiloxane-polycarbonate (Si-PC) copolymer or a mixture thereof.

[0037] The polycarbonate resin that can be included in the resin composition of the present invention is preferably an aromatic polycarbonate resin, but its type is not particularly limited as long as the technical concept of the present invention can be achieved. Thermoplastic aromatic polycarbonate resins commonly used in the art can be used.

[0038] In a specific embodiment, the aromatic polycarbonate resin can be prepared from a dihydric phenol, a carbonate precursor, a molecular weight regulator, etc. The dihydric phenol, as one of the monomers constituting the aromatic polycarbonate resin, can be a substance represented by the following chemical formula 3.

[0039] [Chemical Formula 3]

[0040]

[0041] In the chemical formula 3, X represents a linear, branched, or cyclic alkylene group having no functional group; or a linear, branched, or cyclic alkylene group containing one or more functional groups selected from sulfide, ether, sulfoxide, sulfone, ketone, naphthyl, or isobutylphenyl. More specifically, X can be a linear alkylene group having 1 to 10 carbon atoms, a branched alkylene group having 3 to 10 carbon atoms, or a cyclic alkylene group having 3 to 6 carbon atoms. R1 and R2 independently represent a halogen atom or an alkyl group, for example, a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, or a cyclic alkyl group having 3 to 20 carbon atoms (preferably 3 to 6 carbon atoms). n and m independently represent integers from 0 to 4.

[0042] Non-limiting examples of the dihydric phenols include bisphenol (more specifically 2,2-bis(4-hydroxyphenyl)propane (=bisphenol A)), hydroquinone, 4,4′-dihydroxydiphenyl, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)ether, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane and the like. Phenol, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)naphthylmethane, bis(4-hydroxyphenyl)-(4-isobutylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1-ethyl-1,1-bis(4-hydroxyphenyl)propane, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, 1-naphthyl-1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,10-bis(4-hydroxyphenyl)decane, 2-methyl-1,1-bis(4-hydroxyphenyl)propane, and the like can be preferably used.

[0043] Non-limiting examples of the carbonate precursor as another monomer constituting the aromatic polycarbonate resin include phosgene, phosgene bromide, bishaloformates, diphenyl carbonate, dimethyl carbonate, etc. Preferably, phosgene can be used.

[0044] The molecular weight regulator can be a substance known in the art, that is, a monofunctional compound similar to the monomers used in the preparation of thermoplastic aromatic polycarbonate resins. Non-limiting examples of the molecular weight regulator include phenol-based derivatives (e.g., p-isopropylphenol, p-tert-butylphenol (PTBP), p-cumylphenol, p-isooctylphenol, p-isononylphenol, etc.), aliphatic alcohols, etc., and p-tert-butylphenol (PTBP) can be preferably used.

[0045] The aromatic polycarbonate resin prepared from the dihydric phenol, carbonate precursor and molecular weight modifier described above may be, for example, linear polycarbonate resin, branched polycarbonate resin, copolycarbonate resin, polyester carbonate resin, silicone copolycarbonate, etc., used alone or in combination of two or more.

[0046] The aromatic polycarbonate resin preferably has a viscosity-average molecular weight (Mv, measured in a methylene chloride solution) (g / mol) of 15,000 to 40,000, more preferably 17,000 to 30,000, and most preferably 20,000 to 30,000. If the viscosity-average molecular weight of the aromatic polycarbonate resin is less than 15,000, mechanical properties such as impact strength and tensile strength may be reduced. If the viscosity-average molecular weight exceeds 40,000, problems may arise in resin processing due to increased melt viscosity.

[0047] The polysiloxane-polycarbonate copolymer that may be included in the polycarbonate resin composition of the present invention comprises hydroxyl-terminated siloxane and polycarbonate blocks as repeating units.

[0048] In a specific embodiment, the weight average molecular weight (Mw) of the hydroxyl-terminated siloxane contained in the polysiloxane-polycarbonate copolymer may be 2,500 to 15,000, more specifically 3,500 to 13,000, and even more specifically 4,000 to 9,000. When the weight average molecular weight of the hydroxyl-terminated siloxane is less than 2,500, the effect of improving low-temperature impact resistance may not be significant. When the weight average molecular weight exceeds 15,000, the reactivity decreases, which may cause problems in synthesizing the polysiloxane-polycarbonate copolymer to a desired molecular weight.

[0049] In a specific embodiment, the content of the hydroxyl-terminated siloxane in the polysiloxane-polycarbonate copolymer can be 6.1% by weight or more, 6.5% by weight or more, or 7% by weight or more, based on 100% by weight of the copolymer. The upper limit of the content of the hydroxyl-terminated siloxane in the copolymer is not particularly limited, but in consideration of economic efficiency, it can be 15% by weight or less, 10% by weight or less, or 9% by weight or less.

[0050] In a specific embodiment, the hydroxyl-terminated siloxane in the polysiloxane-polycarbonate copolymer has the following Chemical Formula 4a or Chemical Formula 4:

[0051] [Chemical Formula 4a]

[0052]

[0053] In Chemical Formula 4a, R1 independently represents a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group, or an aryl group. For example, the halogen atom may be Cl or Br, the alkyl group may be an alkyl group having 1 to 13 carbon atoms, such as a methyl group, an ethyl group, or a propyl group, the alkoxy group may be an alkoxy group having 1 to 13 carbon atoms, such as a methoxy group, an ethoxy group, or a propoxy group, and the aryl group may be an aryl group having 6 to 10 carbon atoms, such as a phenyl group, a chlorophenyl group, or a tolyl group.

[0054] R2 independently represents a hydrocarbon group or a hydroxyl group having 1 to 13 carbon atoms. For example, R2 may be an alkyl group or an alkoxy group having 1 to 13 carbon atoms, an alkenyl group or an alkenyloxy group having 2 to 13 carbon atoms, a cycloalkyl group or a cycloalkoxy group having 3 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group or an aralkyloxy group having 7 to 13 carbon atoms, or an alkaryl group or an alkaryloxy group having 7 to 13 carbon atoms.

[0055] R3 independently represents an alkylene group having 2 to 8 carbon atoms.

[0056] m is independently an integer from 0 to 4.

[0057] n is an integer of 30 to 200, preferably an integer of 40 to 170, and more preferably an integer of 50 to 120.

[0058] In one embodiment, as the hydroxyl-terminated siloxane of Chemical Formula 4a, a siloxane monomer ( ), but is not necessarily limited to this.

[0059] [Chemical Formula 4]

[0060]

[0061] In the chemical formula 4, R1, R2, R3 and m are as defined in the chemical formula 4a, n independently represents an integer from 15 to 100, preferably an integer from 20 to 80, more preferably an integer from 25 to 60, and A represents the structure of the following chemical formula 5 or 6.

[0062] [Chemical Formula 5]

[0063]

[0064] In Chemical Formula 5, X is Y or NH-Y-NH, where Y represents a linear or branched aliphatic group having 1 to 20 carbon atoms, a cycloalkylene group (e.g., a cycloalkylene group having 3 to 6 carbon atoms), or a mononuclear or polynuclear arylene group having 6 to 30 carbon atoms that is unsubstituted or substituted with a halogen atom, an alkyl group, an alkoxy group, an aryl group, or a carboxyl group. For example, Y can be an aliphatic group that is unsubstituted or substituted with a halogen atom, an aliphatic group whose main chain contains oxygen, nitrogen, or sulfur atoms, or an arylene group that can be derived from bisphenol A, resorcinol, hydroquinone, or diphenylphenol, and can be represented by the following Chemical Formulas 5a to 5h.

[0065] [Chemical Formula 5a]

[0066]

[0067] [Chemical Formula 5b]

[0068]

[0069] [Chemical Formula 5c]

[0070]

[0071] [Chemical Formula 5d]

[0072]

[0073] [Chemical Formula 5e]

[0074]

[0075] [Chemical Formula 5f]

[0076]

[0077] [Chemical formula 5g]

[0078]

[0079] [Chemical formula 5h]

[0080]

[0081] [Chemical Formula 6]

[0082]

[0083] In Chemical Formula 6, R4 represents an aromatic hydrocarbon group or an aromatic / aliphatic mixed hydrocarbon group having 6 to 30 carbon atoms, or an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Here, R4 may include a structure containing halogen, oxygen, nitrogen, or sulfur in addition to carbon atoms. For example, R4 may be a phenyl group, a chlorophenyl group, or a tolyl group (preferably a phenyl group).

[0084] In a specific embodiment, the hydroxyl-terminated siloxane of Chemical Formula 4 can be the reaction product of the hydroxyl-terminated siloxane of Chemical Formula 4a (wherein n is an integer from 15 to 100) and an acyl compound. The acyl compound can have, for example, an aromatic, aliphatic, or mixed structure containing both aromatic and aliphatic groups. When the acyl compound is aromatic or mixed, it can have 6 to 30 carbon atoms, and when the acyl compound is aliphatic, it can have 1 to 20 carbon atoms. The acyl compound can further contain halogen, oxygen, nitrogen, or sulfur atoms.

[0085] In another specific embodiment, the hydroxyl-terminated siloxane of Chemical Formula 4 may be a reaction product of the hydroxyl-terminated siloxane of Chemical Formula 4a (wherein n is an integer from 15 to 100) and a diisocyanate compound. The diisocyanate compound may be, for example, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, or 4,4'-methylene diphenyl diisocyanate.

[0086] In another specific embodiment, the hydroxyl-terminated siloxane of Chemical Formula 4 may be a reaction product of the hydroxyl-terminated siloxane of Chemical Formula 4a (wherein n is an integer from 15 to 100) and a phosphorus-containing compound (aromatic or aliphatic phosphate compound). The phosphorus-containing compound may be a substance represented by the following Chemical Formula 4b.

[0087] [Chemical Formula 4b]

[0088]

[0089] In the chemical formula 4b, R4 is as defined in the chemical formula 3, and Z independently represents phosphorus, a halogen atom, a hydroxyl group, a carboxyl group, an alkyl group (having 1 to 20 carbon atoms), an alkoxy group, or an aryl group.

[0090] In a specific embodiment, the polycarbonate block in the polysiloxane-polycarbonate copolymer has the following Chemical Formula 7:

[0091] [Chemical Formula 7]

[0092]

[0093] In Chemical Formula 7, R5 represents a divalent alkyl group (having 1 to 20 carbon atoms) (e.g., a divalent alkyl group having 1 to 13 carbon atoms), a cycloalkyl group (e.g., a divalent cycloalkyl group having 3 to 6 carbon atoms), an alkenyl group (e.g., a divalent alkenyl group having 2 to 13 carbon atoms), an alkoxy group (e.g., a divalent alkoxy group having 1 to 13 carbon atoms), or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which is unsubstituted or substituted with a halogen atom or a nitro group.

[0094] The aromatic hydrocarbon group may be derived from a compound having the structure of the following Chemical Formula 7a.

[0095] [Chemical Formula 7a]

[0096]

[0097] In the chemical formula 7a, X represents an alkylene group, a linear, branched, or cyclic alkylene group without a functional group, or a linear, branched, or cyclic alkylene group containing a functional group such as a sulfide, ether, sulfoxide, sulfone, ketone, naphthyl, or isobutylphenyl group. Preferably, X can be a linear or branched alkylene group having 1 to 10 carbon atoms or a cyclic alkylene group having 3 to 6 carbon atoms; R6 independently represents a halogen atom or an alkyl group, for example, a linear or branched alkyl group having 1 to 20 carbon atoms or a cyclic alkyl group having 3 to 20 carbon atoms (preferably 3 to 6); and n and m independently represent integers from 0 to 4.

[0098] The compound of the chemical formula 7a includes, for example, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)naphthylmethane, bis(4-hydroxyphenyl)-(4-isobutylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1-ethyl-1,1-bis(4-hydroxyphenyl)propane, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, 1-naphthyl-1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,10-bis(4-hydroxyphenyl)decane, 2-methyl-1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2, 2-Bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)hexane, 2,2-bis(4-hydroxyphenyl)nonane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-fluoro-4-hydroxyphenyl)propane, 4-methyl-2,2-bis(4-hydroxyphenyl)pentane, 4,4-bis(4-hydroxyphenyl)heptane, diphenyl-bis(4-hydroxyphenyl)methane, resorcinol, hydroquinone, 4,4'-dihydroxyphenyl ether [bis(4-hydroxyphenyl) ether], 4,4'-dihydroxy-2,5-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, bis(3,5- 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclododecane, 1,1-bis(4-hydroxyphenyl)cyclododecane, 1,1-bis(4-hydroxyphenyl)cyclododecane, 1,1-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)decane alkane, 1,4-bis(4-hydroxyphenyl)propane, 1,4-bis(4-hydroxyphenyl)butane, 1,4-bis(4-hydroxyphenyl)isobutane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(3-chloro-4-hydroxyphenyl)propane, bis(3,5-dimethyl-4-hydroxyphenyl)methane, bis(3,5-dichloro-4-hydroxyphenyl)methane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methyl-butane, 4,4'-thiodiphenol [bis(4-hydroxyphenyl)sulfone], bis(3,5-dimethyl-4-hydroxyphenyl) sulfone, bis(3-chloro-4-hydroxyphenyl) sulfone, bis(4-hydroxyphenyl) sulfide, bis(4-hydroxyphenyl) sulfoxide, bis(3-methyl-4-hydroxyphenyl) sulfide, bis(3,5-dimethyl-4-hydroxyphenyl) sulfide, bis(3,5-dimethyl-4-hydroxyphenyl) sulfide, bis(3,5-dibromo-4-hydroxyphenyl) sulfoxide, 4,4'-dihydroxybenzophenone, 3,3',5,5'-tetramethyl-4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl, methylhydroquinone, 1,5-dihydroxynaphthalene and 2,6-dihydroxynaphthalene. Among them, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is a representative example. Other functional dihydric phenols can refer to U.S. Patents No. US2,999,835, US3,028,365, US3,153,008 and US3,334,154, etc. The dihydric phenols can be used alone or in combination of two or more.

[0099] In the case of a carbonate precursor, as other monomers of the polycarbonate resin, for example, phosgene, phosgene, bishaloformate, diphenyl carbonate, or dimethyl carbonate can be used.

[0100] The polysiloxane-polycarbonate copolymer used in the present invention preferably has a viscosity average molecular weight (Mv) of 15,000 to 30,000, more preferably 17,000 to 22,000. If the viscosity average molecular weight of the polysiloxane-polycarbonate copolymer is less than 15,000, mechanical properties may be significantly degraded, and if the viscosity average molecular weight exceeds 30,000, problems may arise in resin processing due to increased melt viscosity.

[0101] In one specific embodiment, the polyester resin composition of the present invention may contain the polycarbonate (PC), polysiloxane-polycarbonate (Si-PC) copolymer, or a mixture thereof (hereinafter also referred to as "resin component (C)") in an amount of more than 3 parts by weight to less than 17 parts by weight, based on 100 parts by weight of the total composition. If the content of resin component (C) is less than 3 parts by weight per 100 parts by weight of the total composition, the flame retardancy and transmittance of the composition may decrease. If the content is greater than 17 parts by weight, the physical properties of the composition may deteriorate, and the deviation in laser transmittance may increase.

[0102] More specifically, within 100 parts by weight of the total polyester resin composition of the present invention, the resin component (C) may be included in an amount of, for example, more than 3 parts by weight, 3.1 parts by weight or more, 3.5 parts by weight or more, 4 parts by weight or more, 4.5 parts by weight or more, or less than 17 parts by weight, 16.9 parts by weight or less, 16.5 parts by weight or less, 16 parts by weight or less, 15.5 parts by weight or less, or 15 parts by weight or less, but is not particularly limited thereto.

[0103] In a specific embodiment, in the polyester resin composition of the present invention, the polysiloxane-polycarbonate (Si-PC) copolymer may be included in an amount of 10 parts by weight or less, more specifically 5 to 10 parts by weight, based on 100 parts by weight of the total composition, but is not particularly limited thereto.

[0104] (D) Flame retardant

[0105] The polyester resin composition of the present invention further comprises a flame retardant.

[0106] In a specific embodiment, the flame retardant may be a halogen-free flame retardant, more specifically a phosphorus-based flame retardant.

[0107] In a specific embodiment, non-limiting examples of the phosphorus-based flame retardant include phosphate compounds, more specifically, the phosphate compounds shown in the following Chemical Formula 8:

[0108] [Chemical Formula 8]

[0109]

[0110] In the chemical formula 8, R1, R2, R3 and R4 are independently C1-C8 alkyl, C5-C6 cycloalkyl, C6-C 20 Aryl or C7-C 20 Aralkyl. Particularly preferred aryl groups are cresol, phenyl, xylyl, propylphenyl, or butylphenyl. n can independently be 0 or 1, preferably 1. N is 0 to 10, preferably 0.3 to 8, and more preferably 0.5 to 5. X is a mononuclear aromatic group or a polynuclear aromatic group having 6 to 30 carbon atoms, preferably diphenylphenol, bisphenol A, resorcinol, or hydroquinone.

[0111] The phosphate compound is also preferably a phosphate compound of the following Chemical Formula 9:

[0112] [Chemical Formula 9]

[0113]

[0114] In the chemical formula 9, R1, R2, R3, R4, n and N are as defined in the chemical formula 8, and Y represents a C1-C7 alkylene, a C1-C7 alkylene, a C5-C 12 Cycloalkylene, C5-C 12 Cycloalkylene, -O-, -S-, -SO-, -SO2- or -CO-, a represents an integer from 0 to 2. Preferably, Y is a C1-C7 alkylene, more preferably an isopropylidene or methylene group.

[0115] The phosphate compound that can be used as the phosphorus-based flame retardant in the present invention can be a monophosphate (N=0), an oligophosphate (N=1-10), or a mixture of a monophosphate and an oligophosphate.

[0116] In a specific embodiment, the phosphorus-based flame retardant may be one or more selected from resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), or N,N′-bis[di-(2,6-xylyl)phosphoryl]-piperazine.

[0117] In one specific embodiment, the polyester resin composition of the present invention may contain the flame retardant in an amount of more than 5 parts by weight to less than 15 parts by weight, based on 100 parts by weight of the total composition. If the content of the flame retardant is less than 5 parts by weight, the flame retardancy of the composition may be reduced. If the content is greater than 15 parts by weight, the processability and physical properties of the composition may be reduced.

[0118] More specifically, within a total of 100 parts by weight of the polyester resin composition of the present invention, the flame retardant may be included in an amount of, for example, more than 5 parts by weight, 5.1 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more, or less than 15 parts by weight, 14.9 parts by weight or less, 14.5 parts by weight or less, 14 parts by weight or less, 13.5 parts by weight or less, or 13 parts by weight or less, but is not particularly limited thereto.

[0119] (E) Filler

[0120] The polyester resin composition of the present invention may further contain a filler.

[0121] The filler is used to improve the heat resistance and dimensional stability of the composition, and can be a fibrous material, a flaky material, a particulate material, or a combination thereof. These fillers can be used alone or in combination.

[0122] More specifically, the filler can be inorganic fibers (e.g., glass, asbestos, carbon, silica, alumina, silica-alumina, aluminosilicate, zirconia, potassium titanate, silicon carbide, etc.), inorganic whiskers (e.g., silicon carbide, alumina, boron nitride, etc.), organic fibers (e.g., aliphatic or aromatic polyamides, aromatic polyesters, fluorine-containing resins, acrylic resins (e.g., polyacrylonitrile, rayon, etc.) and other fibrous materials; flaky materials such as talc, mica, glass, graphite; particulate materials such as glass beads, glass powder, ground fibers (e.g., ground glass fibers); or can be flaky, columnar or fibrous wollastonite, etc., or combinations thereof, but are not limited thereto.

[0123] In a specific embodiment, the average diameter of the fibrous material can be, for example, 1-50 μm, specifically 3-30 μm, and the average length can be, for example, 100 μm to 3 mm, specifically 300 μm to 1 mm, and more specifically 500 μm to 1 mm. Furthermore, the average particle size of the flaky or particulate material can be, for example, 0.1-100 μm, specifically 0.1-50 μm (e.g., 0.1-10 μm).

[0124] In a specific embodiment, the filler can be glass or glass-like fillers (particularly glass fibers, glass flakes, glass beads, etc.), talc, mica, wollastonite or potassium titanate fibers, more particularly glass fibers, especially chopped strand products that are typically cut into short fiber lengths.

[0125] In one specific embodiment, the polyester resin composition of the present invention may include the filler in an amount of 10-50 parts by weight based on 100 parts by weight of the total composition. If the filler content is less than 10 parts by weight per 100 parts by weight of the total composition, the effect of improving the heat resistance and mechanical properties of the composition due to the addition of the filler may not be fully achieved. If the filler content exceeds 50 parts by weight, the surface gloss of the composition may be significantly reduced.

[0126] More specifically, within a total of 100 parts by weight of the polyester resin composition of the present invention, the filler may be included in an amount of, for example, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, or 30 parts by weight or less, 50 parts by weight or less, 45 parts by weight or less, or 40 parts by weight or less, but is not particularly limited thereto.

[0127] The polyester resin composition of the present invention may contain, in addition to the above-mentioned components, one or more additives commonly used in thermoplastic resin compositions.

[0128] If present, these additives can each be used in an amount of 0.01 to 10 parts by weight or 0.01 to 5 parts by weight, based on 100 parts by weight of the total composition.

[0129] In one embodiment, the additive may be an auxiliary flame retardant.

[0130] The auxiliary flame retardant may be, for example, a fluorinated polyolefin-based resin, more specifically polytetrafluoroethylene (PTFE); polyvinylidene fluoride; a copolymer of tetrafluoroethylene and vinylidene fluoride; a copolymer of tetrafluoroethylene and hexafluoropropylene; styrene acrylonitrile-modified polytetrafluoroethylene, acrylic acid-modified polytetrafluoroethylene, or a mixture of two or more thereof, more specifically acrylic acid-modified polytetrafluoroethylene, but not limited thereto. The acrylic acid-modified polytetrafluoroethylene may contain 45-55% by weight of the total weight of the acrylic acid-modified polytetrafluoroethylene. The acrylic acid-modified polytetrafluoroethylene may be in a powder or granular form.

[0131] In a particular embodiment, the additive may be an antioxidant.

[0132] The antioxidants include, for example, organic phosphites such as tris(nonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and distearylpentaerythritol diphosphite; alkylated monophenols or polyphenols; alkylation reaction products of polyphenols with dienes, such as tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane; butylation reaction products of p-cresol or dicyclopentadiene; alkylated hydroquinones; hydroxylated thiodiphenyl ethers; alkylene-bisphenols; benzyl compounds; β-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid with monohydric or polyhydric alcohols; Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid and monohydric or polyhydric alcohols; esters of thioalkyl or thioaryl compounds, such as distearyl thiopropionate, dilauryl thiopropionate, ditridecyl thiodipropionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, etc.; amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, etc., or a combination comprising more than one of the antioxidants.

[0133] In one embodiment, the additive may be a mold release agent.

[0134] The release agent includes, for example, phthalates such as dioctyl-4,5-epoxy-hexahydrophthalate; tris-(octyloxycarbonylethyl) isocyanurate; tristearin; difunctional or multifunctional aromatic phosphates such as resorcinol tetraphenyl diphosphate, bis(diphenyl) phosphate of hydroquinone and bis(diphenyl) phosphate of bisphenol-A; poly-α-olefins; epoxidized soybean oil; silicones including silicone oils; esters, for example, fatty acid esters such as alkyl stearyl esters, for example, methyl stearate; stearyl stearate, pentaerythritol tetrastearate, etc.; a combination of hydrophilic and hydrophobic nonionic surfactants comprising methyl stearate and polyethylene glycol polymers, polypropylene glycol polymers and copolymers thereof, for example, methyl stearate and polyethylene-polypropylene glycol copolymers in a suitable solvent; waxes such as beeswax, montan wax, and paraffin wax.

[0135] In one embodiment, the additive may be a stabilizer.

[0136] The stabilizer includes, for example, organic phosphites such as triphenylphosphite, tris(2,6-dimethylphenyl)phosphite, and tris(mixed monononylphenyl and dinonylphenyl)phosphite; phosphonates such as dimethylphenylphosphonate, phosphates such as trimethyl phosphate, or a combination of more than one of the stabilizers.

[0137] The polyester resin composition of the present invention exists in the form of a melt-mixed blend, in which all polymer components are well dispersed with each other, and all non-polymer components are evenly dispersed in the polymer matrix and combined by the polymer matrix to form a single integral body of the blend. Any melt-mixing method can be used to mix the component materials to obtain a blend. A melt mixer, such as a single-screw or twin-screw extruder, a mixer, a mixing mill, a Banbury (Banbury) mixer, etc., can be used to provide a resin combination. Alternatively, a portion of material can be mixed in a melt mixer, and then the remaining material is added and further melt-mixed. When preparing the composition of the present invention, the mixing sequence can be as understood by those skilled in the art, and each component can be melted once, or fillers and / or other components can be supplied from side feeders, etc.

[0138] The polyester resin composition of the present invention has a laser transmittance exceeding 18%, and more preferably may be 18.1% or more, 19% or more, 20% or more, 21% or more, 22% or more, 23% or more, 24% or more, 25% or more, 26% or more, 27% or more, 28% or more, or 29% or more. The upper limit of the laser transmittance is not particularly limited, and may be, for example, 40% or less, 39% or less, 38% or less, 37% or less, 36% or less, 35% or less, or 34% or less, but is not limited thereto.

[0139] In a specific embodiment, the laser transmittance may be the transmittance of a 980 nm wavelength laser (near infrared ray (NIR)) obtained by injection molding a test piece having a thickness of 1.5 mm, obtained by injection molding the polyester resin composition of the present invention.

[0140] In addition, in a specific embodiment, the polyester resin composition of the present invention may satisfy one or more of the following conditions (i) to (iv), more preferably two or more, even more preferably three or more, and most preferably all of them:

[0141] (i) V-0 flame retardancy rating at 1.5mm thickness in UL94 flame retardancy test;

[0142] (ii) when the mold temperature condition during injection is changed from 60°C to 80°C, the laser transmittance (more specifically, the 980 nm laser transmittance) deviates from 5 or less (more specifically, 4 or less);

[0143] (iii) Tensile strength of 120 MPa or more, 6 KJ / m 2 Impact strength above 100℃ and heat deformation temperature (HDT) above 160℃;

[0144] (iv)4.5KJ / m 2 Above low temperature impact strength (-30℃).

[0145] In a specific embodiment, the polyester resin composition of the present invention can be used as a laser welding transmission layer material.

[0146] According to another aspect of the present invention, a molded article comprising the polyester resin composition of the present invention is provided.

[0147] The molded article of the present invention is prepared by extruding, casting, blow molding or injection molding a melt of the polyester resin composition of the present invention. The molded article can be in the form of a film or a sheet.

[0148] In a specific embodiment, the molded article of the present invention can be laser welded, more specifically black laser welded.

[0149] The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the scope of the present invention is not limited thereto.

[0150] [Example]

[0151] The components used in the examples and comparative examples of the present invention are as follows, and the content of each component is shown in Table 1.

[0152] (A): Polybutylene terephthalate (PBT) (IV: about 1.1 dl / g) (211H, Changchun)

[0153] (B): Polyethylene terephthalate (PET) (JSB194, Huevis)

[0154] (C-1): Polycarbonate (PC) (TRIREX 3022PJ, Samyang Corporation)

[0155] (C-2): Polysiloxane-polycarbonate (Si-PC) (TRIREX ST63022PJ, Samyang Corporation)

[0156] (D): Metal phosphinate-based flame retardant (Exolit OP1240, Clariant)

[0157] (E): Glass fiber filler (CS321, KCC)

[0158] Examples 1 to 18 and Comparative Examples 1 to 8

[0159] The ingredients were uniformly mixed in a super mixer according to the composition ratios shown in Table 1 below, melt-kneaded in a twin-screw extruder at 220-280°C, and extruded into pellets. After drying at 100°C for at least 5 hours, pellets were molded using an LS 170-ton injection molding machine at an injection temperature range of 220-280°C, a mold range of 50-110°C, and an injection pressure of 30 to 70. The properties of each prepared composition were measured and summarized in Table 2 below.

[0160] The physical properties of the test pieces prepared in the Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 2 below.

[0161] -Tensile strength (MPa): measured according to ISO527.

[0162] -Impact strength (KJ / m 2 ): Measured according to ISO 179.

[0163] -Heat distortion temperature (HDT) (°C): measured according to ISO75.

[0164] - Flame retardancy: measured according to the UL94V test method using a test piece with a thickness of 1.5 mm.

[0165] - Transmittance: Measured using a EuroVision laser transmittance measuring device in the 980 nm wavelength region on a square test piece injection-molded to a thickness of 1.5 mm.

[0166] - Transmittance deviation: During injection, the mold temperature conditions were changed from 60°C to 80°C. The transmittance at each mold temperature was measured and the difference was taken as the transmittance deviation.

[0167] -Low temperature impact strength (KJ / m 2 ): Measured according to ISO 179 at -30°C.

[0168]

[0169]

[0170]

[0171]

[0172]

[0173]

[0174] As shown in Table 2, the compositions of Examples 1 to 18 exhibited excellent mechanical properties and flame retardancy, as well as high laser transmittance, and the transmittance deviation value according to the mold temperature conditions was also small.

[0175] On the other hand, compared with the examples, the laser transmittance of the compositions of the comparative examples is significantly lower (Comparative Examples 1 to 4, 7, and 8), or the laser transmittance deviation value is significantly larger (Comparative Examples 1 to 4, 7, and 8), or the flame retardancy is poor (Comparative Examples 1 and 2), or the HDT is low, resulting in poor heat resistance (Comparative Examples 5 and 6), or the impact strength is reduced (Comparative Examples 1 to 4, 7, and 8), or the tensile strength is reduced (Comparative Examples 5 and 6), or the low-temperature impact strength is reduced (Comparative Examples 1 to 4, 7, and 8), etc., and at least one of the evaluated physical properties is poor.

Claims

1. A polyester resin composition comprising: (A) polybutylene terephthalate; (B) polyethylene terephthalate; (C) polycarbonate, polysiloxane-polycarbonate copolymer, or mixtures thereof; and (D) flame retardants; in, The polybutylene terephthalate is included in an amount of more than 1 part by weight to less than 3.2 parts by weight relative to 1 part by weight of the polyethylene terephthalate, and the laser transmittance of the composition exceeds 18%.

2. The polyester resin composition according to claim 1, wherein The polycarbonate is an aromatic polycarbonate.

3. The polyester resin composition according to claim 1, wherein The polysiloxane-polycarbonate copolymer comprises hydroxyl-terminated siloxane and polycarbonate blocks as repeating units.

4. The polyester resin composition according to claim 1, wherein The flame retardant is a halogen-free flame retardant. The polyester resin composition according to claim 1 , further comprising a filler.

6. The polyester resin composition according to claim 5, wherein The filler is glass fiber.

7. The polyester resin composition according to claim 1, which satisfies one or more of the following conditions (i) to (iv): (i) V-0 flame retardancy rating at 1.5mm thickness in UL94 flame retardancy test; (ii) When the mold temperature condition during injection is changed from 60°C to 80°C, the laser transmittance deviation is less than 5; (iii) Tensile strength of 120 MPa or more, 6 KJ / m 2 Impact strength above 100℃ and heat deformation temperature (HDT) above 160℃; (iv)4.5KJ / m 2 Above low temperature impact strength (-30℃).

8. The polyester resin composition according to claim 1, wherein The polyester resin composition is used as a laser welding transmission layer material. 9 . A molded article comprising the polyester resin composition according to claim 1 .

10. The molded article according to claim 9, wherein The molded product can be laser welded.

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