Bromine antimony type flame-retardant reinforced polyester composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a bromine-antimony flame-retardant reinforced polyester composite material as well as a preparation method and application thereof. The composite material comprises polyethylene glycol terephthalate resin, a main flame retardant, an auxiliary flame retardant, a flexibilizer, a crystallization promoter, a nucleating agent, a laser marking white auxiliary agent, carbon black, glass fiber, a lubricant and other functional auxiliary agents, wherein the main flame retardant is a bromine-containing flame retardant; the auxiliary flame retardant is an antimony-containing flame retardant; the laser marking white auxiliary agent is a mixture of a fluorescent whitening agent and inorganic salt; the inorganic salt comprises carbonate and / or phosphate; the other functional additives comprise an antioxidant, a heat stabilizer and polytetrafluoroethylene. The composite material disclosed by the invention has rapid crystallinity, high heat resistance and dimensional stability, and can meet the requirements that a device is not deformed after being cured and baked at high temperature after being packaged, a PCB (Printed Circuit Board) is not melted and scorched during soldering furnace wave soldering during assembly, and laser marking white characters still have excellent definition and contrast ratio after being baked at high temperature.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a bromine-antimony type flame-retardant reinforced polyester composite material and a preparation method and application thereof. Background Art

[0002] At present, with the advancement of science and technology and the expansion of demand, the fields of 5G, big data, Internet of Things, and new energy industries will usher in vigorous development, and the production demand and quality requirements of electronic and electrical products closely related to them will continue to increase. Relays and capacitors, as the smallest components in this field, will face a higher voltage and higher current working environment, requiring better thermal stability, better flame retardancy, smaller size and higher safety requirements. At the same time, the clarity and contrast requirements of the surface model, specification, certification (UL / CQC / VDE) and other logos of the parts are also higher. Therefore, the requirements for engineering plastic materials that are injection molded into relays, capacitor housings, bases, frames, etc. will also continue to increase.

[0003] The main materials for the housing, base and skeleton of relays and capacitors for low-voltage electrical appliances on the market are modified flame-retardant reinforced polybutylene terephthalate (PBT), which has good creep resistance, fatigue resistance, friction resistance, excellent electrical insulation performance, non-toxicity, good weather resistance, chemical resistance, weak acid resistance and organic solvent resistance. Compared with it, modified polyethylene terephthalate (PET) has better mechanical properties, higher heat deformation temperature and thermal stability, can meet more stringent use environments, and has higher cost performance. Therefore, in the current more intense market competition environment, there has been a trend of partially replacing modified flame-retardant reinforced PBT.

[0004] Since polyethylene terephthalate has only diols connected to both sides of the benzene ring on the molecular chain, the molecular chain is relatively rigid, the folding and rotating activity is weak, and the glass transition temperature of the resin is relatively high (about 75°C). The crystallization speed is slow and the molding cycle is long during the injection molding process. When PET is not modified by crystallization promoters and nucleating agents, it is more likely to have cis "pseudo-crystallization" of the PET molecular chain rather than trans crystallization after the molecular chain rotates. The material is brittle and has poor thermal stability after molding. In terms of crystallization molding, many scholars initially solved the molding crystallization problem from the injection molding process. By increasing the mold temperature to make it higher than the glass transition temperature of PET, the molded parts are molded. This method has high requirements for molding equipment and high energy consumption. Later, scholars modified PET by adding nucleating agents to improve the crystallinity of the material, realize the injection molding of modified PET at a lower mold temperature, and shorten the molding time, but the surface of the injection molded parts is poor, and the surface flow marks and glass fiber flow lines are obvious. Scholars introduced crystallization promoters to reduce the glass transition temperature of modified PET. At this time, the molding goals of low mold temperature, short molding cycle and good surface have been basically achieved. However, in the process of replacing modified flame-retardant reinforced PET with modified flame-retardant reinforced PBT, relay and capacitor molding manufacturers have proposed that the modified PET parts can be switched to injection molding with a slight adjustment based on the existing PBT mold and molding process. Therefore, higher flow speed and faster molding speed requirements are proposed for modified flame-retardant reinforced PET. In addition, in order to cope with the safety and stability of relays and capacitors under more severe working conditions such as higher voltage, larger current and higher operating temperature, the relays and capacitors after the glue encapsulation will be cured and baked under higher temperature (above 150℃, more than 2h) conditions to detect the dimensional stability, sealing and laser printing clarity of the parts. After passing the test, the parts will be tested in a tin furnace at 430±20℃ and 5s to see if the surface of the parts is melted and charred, and the high temperature resistance of the material will be judged.

[0005] In the related art, the patent document with publication number CN112521729A discloses a high-fluidity black flame-retardant reinforced polyethylene terephthalate composition and its preparation method. The patent document greatly improves the fluidity and crystallization performance of the material by adjusting the viscosity of the PET resin and introducing a crystallization nucleating agent and a crystallization accelerator. However, in thin-wall injection molding, high fluidity and high crystallinity will cause the PET crystal to produce cis "pseudo-crystallization" crystallization when cooling at low mold temperature. The uneven size of the crystal particles causes the molecular chain to be unstable and easy to slide, and the parts are prone to warping and deformation in the subsequent high-temperature curing and long-term baking process. In addition, the black flame-retardant reinforced PET system, especially the bromine antimony flame-retardant system, is easy to be unclear when laser-marked white characters, burnt and yellowed, and the clarity and contrast of the white characters marked on the surface of the parts after high-temperature baking are particularly obvious.

[0006] Therefore, the development of a bromine-antimony flame-retardant reinforced polyester composite material not only meets the development needs of today's industrial society, but also promotes the development of high-performance functional materials, which is of great practical significance. Summary of the invention

[0007] The present invention provides a bromine-antimony type flame-retardant reinforced polyester composite material and a preparation method and application thereof, so as to solve the problems that the existing flame-retardant reinforced polyester composite material has the problem of easy burning and yellowing of laser-marked white characters, reduced clarity and contrast of surface markings, easy deformation, etc. after high-temperature curing and baking.

[0008] According to a first aspect of the present invention, the present invention provides a bromine-antimony flame-retardant reinforced polyester composite material, which comprises the following components in parts by weight: 20.0-65.0 parts of polyethylene terephthalate resin; Main flame retardant 5.0~15.0 parts; Auxiliary flame retardant 1.0~10.0 parts; Toughening agent 0.5~6.0 parts; Crystallization accelerator 0.3~3.0 parts; Nucleating agent 0.3~3.0 parts; Laser marking white additive 0.01~1.0 part; Carbon black 0.1~2.0 parts; Glass fiber 15.0~55.0 parts; Lubricant 0.1~2.0 parts; Other functional additives 0.1~5.0 parts; Among them, the main flame retardant is a bromine-containing flame retardant; the auxiliary flame retardant is an antimony-containing flame retardant; the laser marking white additive is a mixture of a fluorescent whitening agent and an inorganic salt; the inorganic salt includes carbonates and / or phosphates; and the other functional additives include antioxidants, heat stabilizers and polytetrafluoroethylene.

[0009] Aiming at the problems of the bromine-antimony flame retardant system, such as the laser-marked white characters are easy to burn and turn yellow after high-temperature curing and baking, the clarity and contrast of the surface marking are reduced, and deformation is easy to occur, the present invention provides a bromine-antimony flame retardant reinforced polyester composite material, in which a specific component of laser marking white auxiliary agent is added, wherein the fluorescent brightener can improve the contrast of the white characters on the surface of the black workpiece after high-temperature baking, and the specific inorganic salt compound can further deepen the clarity and whiteness of the outline when the white characters are laser marked, and the two synergistically improve the surface marking clarity and contrast of the laser-marked white characters after high-temperature curing and baking of the polyester composite material, and at the same time weaken the influence of the bromine-antimony flame retardant being easy to burn and turn yellow during laser marking. The present invention provides a bromine-antimony flame retardant reinforced polyester composite material, in which other functional auxiliary agents of specific composition are added, wherein the compounding of the antioxidant and the heat stabilizer ensures that the size and surface color of the relay and capacitor are stable under the curing and baking conditions of higher temperature (>150°C,>2h), and the polytetrafluoroethylene forms an organic polymer network at high temperature to wrap the entire workpiece, ensuring that the material passes the tin furnace (430±20°C, 5s) test.

[0010] Furthermore, the fluorescent whitening agent is selected from one or more of 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene (OB), 4,4′-bis(2-benzoxazolyl)stilbene (OB-1), 4,4-bis(2-dimethoxyphenylvinyl)biphenyl (FP-127), and 1,4-bis(benzoxazolyl-2-yl)naphthalene (KCB); the inorganic salt is selected from one or more of sodium carbonate, sodium bicarbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, or trisodium phosphate. Preferably, the weight ratio of the fluorescent whitening agent to the inorganic salt is 1: 3 to 3: 1. By limiting the weight ratio of the fluorescent whitening agent to the inorganic salt within a reasonable range, the two can play a better synergistic role and improve the performance of the material after high-temperature baking.

[0011] Furthermore, the antioxidant is a compound of a hindered phenol antioxidant and a phosphite antioxidant; the heat stabilizer is selected from one or more of metal soap compounds, organic tin compounds, organic antimony compounds, epoxy compounds, phosphite compounds, polyol compounds or diphenylthiourea compounds.

[0012] In some specific embodiments, the antioxidant includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite.

[0013] Preferably, the antioxidant accounts for 0.3-0.6% of the total weight of the bromine-antimony flame-retardant reinforced polyester composite material; the heat stabilizer accounts for 0.1-0.4% of the total weight of the bromine-antimony flame-retardant reinforced polyester composite material; and the polytetrafluoroethylene accounts for 0.15-0.3% of the total weight of the bromine-antimony flame-retardant reinforced polyester composite material. By limiting the usage ratio of antioxidants, heat stabilizers and polytetrafluoroethylene within a reasonable range, a better synergistic effect can be formed between the three, and the dimensional stability and surface color stability of relays and capacitors after injection molding and glue filling assembly under higher temperature (>150°C, >2h) curing and baking conditions can be better improved.

[0014] In some specific embodiments, the heat stabilizer is zinc sulfide, which has good thermal stability and can maintain good mechanical properties under high temperature conditions.

[0015] Furthermore, the main flame retardant is one or more of brominated polystyrene, brominated epoxy resin, brominated polycarbonate, decabromodiphenylethane, and brominated triazine.

[0016] Furthermore, the auxiliary flame retardant is an antimony-containing compound, and the antimony-containing compound is one or both of antimony trioxide and sodium antimonate.

[0017] It should be noted that the antimony-containing compound may be a masterbatch type antimony-containing compound or a powder type antimony-containing compound.

[0018] Preferably, the carrier in the masterbatch antimony-containing compound is obtained by modifying the toughening resin with a silane coupling agent. In the black bromine / antimony flame retardant reinforced resin system, the antimony element easily absorbs energy during laser marking, causing carbonization and burning of the material surface, resulting in unclear fonts. By refining the antimony-containing compound into a masterbatch and coating the surface of the antimony compound with a layer of toughening agent, the carbonization and burning caused by the strong absorption of laser energy by the antimony element can be eliminated, thereby improving font clarity.

[0019] More preferably, the toughening resin contains one or more of maleic anhydride group, acrylate group, epoxy group, isocyanate group; and the silane coupling agent is selected from one or more of KH550, KH560 or KH570.

[0020] Furthermore, the viscosity of the polyethylene terephthalate resin is 0.5-1.1 dl / g. The viscosity of the polyethylene terephthalate resin is an important factor affecting the material processing performance, molding efficiency, product physical properties and mechanical properties. By adjusting the viscosity of PET, the performance of the material can be optimized to meet specific application requirements.

[0021] Furthermore, the polyethylene terephthalate resin is obtained by vacuum de-VOC treatment or low-viscosity PET resin (e.g., PET resin with a viscosity of less than or equal to 0.65 dl / g). The polyethylene terephthalate resin obtained by vacuum de-VOC treatment or low-viscosity PET resin can be selected to eliminate small molecular organic substances that are easily precipitated and decomposed in the resin matrix, improve the thermal stability of the material, and eliminate the easy precipitation in the high-temperature curing section after the glue filling of relays and capacitor components, resulting in deformation of the shell size of the product and poor sealing effect, and the precipitation of small molecular organic substances on the surface is easy to burn and yellow when laser marking white characters, resulting in unclear fonts and poor contrast.

[0022] Furthermore, the crystallization accelerator is one or more of polycaprolactone and its end-capped compounds, polyethylene glycol and its end-capped compounds, polypropylene glycol and its end-capped compounds, polyolefins, modified polyolefins or polyamides.

[0023] In some specific embodiments, the crystallization accelerator is composed of polyethylene glycol ethylene glycol and polybutylene succinate. In some specific embodiments, the weight ratio of polyethylene glycol ethylene glycol and polybutylene succinate is 1:1.

[0024] Furthermore, the nucleating agent is selected from one or more of an organic nucleating agent and an inorganic nucleating agent.

[0025] The organic and inorganic compound of crystallization accelerator and nucleating agent is used to "thaw" the PET molecular chain through compounding crystallization accelerator to improve the fluidity of the material. At the same time, the PET molecular chain is rotated from the cis structure to the trans structure. The inorganic nano-nucleating agent is used as the crystal seed and the organic nucleating agent molecular chain guides the crystallization, so that the modified flame-retardant reinforced PET can be crystallized quickly, and the molding production cycle is shortened to the same as that of the modified PBT. The PET molecular chain crystallizes in the trans structure, with high crystallinity and dense crystal structure, which ensures the dimensional stability and sealing of the parts in the later high-temperature curing and baking section of relays and capacitors.

[0026] Inorganic nucleating agents include clay nucleating agents and / or inorganic salt nucleating agents, and clay nucleating agents include one or more of talc, calcium oxide, carbon black, calcium carbonate, mica, inorganic pigments, and kaolin. Inorganic salt nucleating agents include carbonates, silicates, sulfates, phosphates, and metal salts.

[0027] The organic nucleating agent includes one or more of monocarboxylic acid (Na, Li, Ba, Mg, Ca) salts, benzoic acid (Na, K, Ca) salts, aromatic hydroxysulfonic acid metal salts, organic phosphorus compound (Mg, Zn) salts, (K, Na) ionomers, alkali metal salts of polyester oligomers, micropowders of fully aromatic polyesters, and PTFE powders.

[0028] In some specific embodiments, the nucleating agent is composed of an organic nucleating agent or an inorganic nucleating agent. Preferably, the combination of an organic nucleating agent and an inorganic nucleating agent has the best effect.

[0029] In some specific embodiments, the organic nucleating agent is a derivative of ethylene methacrylic acid (E / MAA) copolymer, and the inorganic nucleating agent is 8000-12500 mesh talc. Preferably, the weight ratio of the derivative of ethylene methacrylic acid (E / MAA) copolymer to the talc is 1:1.

[0030] Furthermore, the following components are included according to parts by weight: 33.0-50.0 parts of polyethylene terephthalate resin; Main flame retardant 10.0~13.0 parts; Auxiliary flame retardant 4.0~5.0 parts; 1.0~2.0 parts of toughening agent; Crystallization accelerator 0.5~1.0 part; Nucleating agent 0.5~2 parts; Laser marking white additive 0.05~0.2 parts; Carbon black 0.3~1.0 part; Glass fiber 30.0~45.0 parts; Lubricant 0.2~1 part; Other functional additives 0.8~1.1 parts.

[0031] Furthermore, the carbon black is medium-pigment carbon black with a particle size of 18-25 nm. Under this condition, the carbon black ensures the color depth of the workpiece after high-temperature baking, and weakens the scorching and yellowing phenomenon caused by the synergistic effect of the bromine antimony flame retardant and carbon black during laser marking. It should be noted that medium-pigment carbon black refers to a carbon black whose blackness reaches or exceeds the No. 3 standard sample.

[0032] Further, the toughening agent is one or more of ethylene-methyl acrylate, ethylene-ethyl acrylate, ethylene-butyl acrylate, low-density polyethylene, ethylene-methyl acrylate-glycidyl ester, ethylene-ethyl acrylate-glycidyl ester, ethylene-butyl acrylate-glycidyl ester, maleic anhydride grafted ethylene-octene copolymer or polyethylene copolymer. Selecting the right type of toughening agent can improve the toughness and impact resistance of the composite material, and may also affect its mechanical properties, interface bonding and crystallization behavior.

[0033] Furthermore, the glass fiber is an alkali-free glass fiber; the diameter of the glass fiber is 9-25um. Furthermore, the alkali-free glass fiber is an alkali-free chopped glass fiber or a continuous alkali-free glass fiber. Selecting the appropriate type of glass fiber can improve the mechanical properties, heat resistance, electrical insulation and chemical resistance of the material, and can also improve the bending performance and anti-penetration performance of the material.

[0034] Furthermore, the lubricant is one or more of montanic acid ester and its derivatives, pentaerythritol stearate, oxidized PE wax, amide wax, zinc stearate, calcium stearate or silicone. Selecting a suitable type of lubricant can improve the tribological properties of the composite material, including reducing the friction coefficient and wear rate, increasing hardness and tensile strength, and enhancing environmental adaptability.

[0035] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned bromine-antimony type flame-retardant reinforced polyester composite material, characterized in that it comprises the following steps: Mixing polyethylene terephthalate resin, a main flame retardant, an auxiliary flame retardant, a toughening agent, a crystallization accelerator, a nucleating agent, a laser marking white additive, carbon black, a lubricant and other functional additives to obtain a premix; The premix is ​​mixed with glass fiber and then extruded, drawn into strips, cooled, dried and granulated; wherein the extrusion temperature is 240-280° C. and the rotation speed is 250-600 rpm.

[0036] The preparation method of the bromine-antimony type flame-retardant reinforced polyester composite material of the present invention is simple, and is conducive to the wide application of the material and the improvement of the market competitiveness.

[0037] According to a third aspect of the present invention, the present invention also provides the use of the above-mentioned bromine-antimony flame-retardant reinforced polyester composite material or the bromine-antimony flame-retardant reinforced polyester composite material prepared according to the above-mentioned preparation method in electronic components. The electronic components include relays, capacitors, sensors, filters, etc.

[0038] The invention discloses a bromine-antimony flame-retardant reinforced polyester composite material, comprising polyethylene terephthalate resin, a main flame retardant, an auxiliary flame retardant, a toughening agent, a crystallization accelerator, a nucleating agent, a laser marking white additive, carbon black, glass fiber, a lubricant and other functional additives. The synergistic effect of the raw materials enables the material to have high fluidity and rapid crystallization, and can meet the production needs of thin-walled, multi-cavity, high-efficiency relays and capacitors. The material also has high heat resistance and dimensional stability, and can meet the requirements of high-temperature curing and baking of relays and capacitors after epoxy encapsulation without warping and deformation, and can meet the requirements of not melting and burning during wave soldering in a soldering furnace during PCB board assembly, and laser-marked white characters still have excellent clarity and contrast after high-temperature baking.

[0039] The preparation method of the bromine-antimony type flame-retardant reinforced polyester composite material of the invention is simple and is mainly used in the field of electronics and electrical appliances. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in the field or the product instructions are used. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased through regular channels.

[0042] Raw material selection of embodiments and comparative examples: Polyethylene terephthalate resin: intrinsic viscosity is 0.64dl / g, brand name is CZ-5011, Jiangsu Sanfangxiang Group Co., Ltd.; intrinsic viscosity is 0.74dl / g, brand name is FG720, Sinopec Yizheng Chemical Fiber Co., Ltd.

[0043] Main flame retardant: brominated polystyrene, brand XZ-6700, Shandong Brothers Technology Co., Ltd.

[0044] Auxiliary flame retardant: sodium antimonate, powder brand is ST-FS-SA, Shanghai Xingbeida Chemical Materials Co., Ltd.; masterbatch brand is FNA-80, Wannapu New Material Technology Co., Ltd.

[0045] Toughening agent: Ethylene-methyl acrylate-glycidyl ester, brand AX8900, Arkema Shanghai Chemical Co., Ltd.

[0046] Crystallization accelerator: polyethylene glycol ester, brand name UNIPLEX 809, Lanxess Chemical (China) Co., Ltd.; polybutylene succinate, brand name TH803S, Blue Mountain Tunhe Chemical Company Polyester Branch.

[0047] Nucleating agent: derivative of ethylene methacrylic acid (E / MAA) copolymer, brand name Surlyn®8920, DuPont, USA; talc powder 10000 mesh, brand name Crystalc 7H, Shanghai Yiruishi (China) Co., Ltd.

[0048] Laser marking white additive: prepared by mixing fluorescent brightener 4,4′-bis(2-benzoxazolyl)stilbene (OB-1) and sodium bicarbonate evenly.

[0049] Carbon black: grade M1300, high pigment carbon black (9 - 17nm), Cabot Corporation, USA; grade M880, medium pigment carbon black (18 - 25nm), Cabot Corporation, USA.

[0050] Glass fiber: grade ECS - 11 - 4.5 534A, glass fiber of Jushi Group.

[0051] Lubricant: pentaerythritol tetrastearate PETS, grade GLYCOLUBE® P, Lonza, USA.

[0052] Other functional additives: pentaerythritol tetra[β-(3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate], grade AT - 10, Lion Specialty Chemicals; tris(2,4 - di - tert - butylphenyl) phosphite, grade Irgafos® Antioxidant® 168, BASF, Germany; zinc sulfide, grade HD - S, Sachtleben; polytetrafluoroethylene, grade DB - 100, Shanghai Puxin Technology Co., Ltd.

[0053] The raw material compositions in the examples and comparative examples are all calculated by weight parts.

[0054] Examples 1 - 19 This example provides a bromine - antimony type flame - retardant reinforced polyester composite material. Its raw material composition is shown in Table 1 and Table 2 below, and its performance characteristics are shown in Table 3 and Table 4 below.

[0055] The preparation method of the bromine - antimony type flame - retardant reinforced polyester composite material is as follows: a. According to the ratio, take polyethylene terephthalate resin, main flame retardant, auxiliary flame retardant, toughening agent, crystallization accelerator, nucleating agent, laser - marking white additive, carbon black, lubricant, and other functional additives and add them into a premixer to mix for 5 - 15 minutes to obtain a premixed material.

[0056] b. Add the premixed material at the main feeding port and add glass fiber at the side feeding port.

[0057] c. Extrude, draw, cool, dry, and pelletize the materials from a twin - screw extruder to obtain a modified composite material. The temperature of the extruder is set at 240 - 280°C, and the main machine speed is 250 - 600 revolutions per minute.

[0058] Comparative Example 1 This comparative example provides a bromine - antimony type flame - retardant reinforced polyester composite material. The difference in its raw material composition from that of Example 1 is that the carbon black used is high - pigment carbon black with a smaller particle size. Its specific composition is shown in Table 5 below. Its preparation method is the same as that of Example 1, and its performance characteristics are shown in Table 6 below.

[0059] Comparative Example 2 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that no laser marking white additive is added. Its specific composition is shown in Table 5 below. Its preparation method does not add a laser marking white additive in step a, and the rest is the same as Example 1. Its performance characteristics are shown in Table 6 below.

[0060] Comparative Example 3 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that the mass ratio of the fluorescent brightener 4,4′-bis(2-benzoxazolyl)stilbene (OB-1) to sodium bicarbonate in the laser marking white additive is 5:1, and its specific composition is shown in Table 5 below. Its preparation method is the same as that of Example 1, and its performance characteristics are shown in Table 6 below.

[0061] Comparative Example 4 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that the mass ratio of the fluorescent brightener 4,4′-bis(2-benzoxazolyl)stilbene (OB-1) to sodium bicarbonate in the laser marking white additive is 1:5, and the preparation method is the same as that of Example 1. The specific composition is shown in Table 5 below, and the performance characteristics are shown in Table 6 below.

[0062] Comparative Example 5 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that other functional additives do not contain the heat stabilizer zinc sulfide, and its specific composition is shown in Table 5 below. Its preparation method is the same as that of Example 1, and its performance characteristics are shown in Table 6 below.

[0063] Comparative Example 6 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that other functional additives do not contain polytetrafluoroethylene, the specific composition of which is shown in Table 5 below, the preparation method of which is the same as that of Example 1, and the performance characteristics of which are shown in Table 6 below.

[0064] Comparative Example 7 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that other functional additives do not contain polytetrafluoroethylene and zinc sulfide, and its specific composition is shown in Table 5 below. Its preparation method is the same as that of Example 1, and its performance characteristics are shown in Table 6 below.

[0065] Comparative Example 8 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that a single crystallization promoter is used, and its specific composition is shown in Table 5 below. Its preparation method is the same as that of Example 1, and its performance characteristics are shown in Table 6 below.

[0066] Comparative Example 9 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that a single nucleating agent is used, and its specific composition is shown in Table 5 below. Its preparation method is the same as that of Example 1, and its performance characteristics are shown in Table 6 below.

[0067] Comparative Example 10 This comparative example provides a bromine-antimony type flame-retardant reinforced polyester composite material, the raw material composition of which is different from that of Example 1 in that no crystallization promoter is added. Its specific composition is shown in Table 5 below, and its preparation method does not add a crystallization promoter in step a. Other aspects are the same as those of Example 1, and its performance characteristics are shown in Table 6 below.

[0068] The performance of the bromine-antimony flame-retardant reinforced polyester composite materials of the examples and comparative examples was tested according to the following test method: Tensile strength: measured according to ASTM D638 standard.

[0069] Flexural strength: measured according to ASTM D790.

[0070] Impact strength: measured according to ASTM D256 standard.

[0071] Flame retardant test: measured according to UL94 standard.

[0072] Material molding cycle test: The shortest time required for the injection molding machine to continuously and stably mold a 20*20*10mm rectangular relay housing is recorded as the material molding cycle. The injection molding machine model is Haitian Injection Molding Machine KEBA-1075.

[0073] Dimensional stability after high-temperature curing and baking: The material was injection molded into a 20*20*10mm rectangular relay housing, cooled completely in a constant temperature and humidity chamber at 25℃ and 50% humidity, placed in a constant temperature blast oven at 150℃ for 2h, then taken out and placed in a constant temperature and humidity chamber at 25℃ and 50% humidity. The deformation dimensions of the housing were measured under a scanning electron microscope. The constant temperature and humidity chamber model is Shanghai Jinghong HWS-150; the constant temperature blast oven model is Shanghai Jinghong DHG-9078A; the scanning electron microscope model is Hitachi SU3800.

[0074] The clarity and contrast of the white characters of the laser marking after high-temperature curing and baking are determined by naked eye and divided into three levels: "good", "average" and "poor". The model of the constant temperature blast oven is Shanghai Jinghong DHG-9078A; the model of the laser marking equipment is Han's Laser EP-12 (1060nm).

[0075] Tin furnace test: After cooling down from injection molding, place the relay housing into a 430±20℃ tin furnace for 5 seconds, and visually judge the degree of melting deformation and burning, which are classified as "none", "general" and "serious".

[0076] Table 1

[0077] Table 2

[0078] Table 3

[0079] Table 4

[0080] Table 5

[0081] Table 6

[0082] It can be seen from the experimental results of Tables 1 to 4 that the bromine-antimony flame-retardant reinforced polyester composite material of the present invention optimizes the composition of each raw material to produce a better synergistic effect between the raw materials, so that the material has excellent flame retardant properties and mechanical strength, and also has rapid crystallization, high heat resistance and dimensional stability, which can meet the requirements of high-temperature curing and baking without warping and deformation of relays and capacitors after epoxy encapsulation, and no melting and burning during soldering in soldering furnace wave soldering during PCB board assembly, and the laser-marked white characters still have excellent clarity and contrast after high-temperature baking. Further, it can be seen from the results of Example 1 and Example 19 that compared with powder-type antimony-containing compounds, the auxiliary flame retardant uses a masterbatch antimony-containing compound (the masterbatch antimony-containing compound is a layer of toughening agent wrapped on the surface of the antimony-containing compound), which can eliminate the carbonization and burning phenomenon caused by the strong absorption of laser energy by the antimony element and improve the clarity of the font.

[0083] It can be seen from the results of Example 1 and Comparative Example 1 that the use of high-pigment carbon black with a smaller particle size will have a great side effect on the printing effect, and the use of medium-pigment carbon black has better clarity and contrast. It can be seen from the results of Example 1 and Comparative Examples 2-4 that by optimizing the laser marking white additive, the laser-marked white characters of the injection molded parts can have excellent clarity and contrast after high-temperature curing and baking. It can be seen from the results of Example 1 and Comparative Examples 5-7 that by adding thermal stabilizers and polytetrafluoroethylene, the dimensions of the relays and capacitors assembled by injection molding and filling are guaranteed to be stable under higher temperature (>150°C, >2h) curing and baking conditions, and the tin furnace (430±20°C, 5s) test is passed. It can be seen from the results of Example 1 and Comparative Examples 8-10 that the organic-inorganic compound of crystallization promoter and nucleating agent can greatly shorten the injection molding cycle and improve production efficiency. At the same time, it will also improve the heat resistance of the material, which is conducive to improving baking deformation and heat solder deformation and scorching.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bromine-antimony flame-retardant reinforced polyester composite material, characterized in that: According to parts by weight, it includes the following components: 20.0-65.0 parts of polyethylene terephthalate resin; Main flame retardant 5.0~15.0 parts; Auxiliary flame retardant 1.0~10.0 parts; Toughening agent 0.5~6.0 parts; Crystallization accelerator 0.3~3.0 parts; Nucleating agent 0.3~3.0 parts; Laser marking white additive 0.01~1.0 part; Carbon black 0.1~2.0 parts; Glass fiber 15.0~55.0 parts; Lubricant 0.1~2.0 parts; Other functional additives 0.1~5.0 parts; Among them, the main flame retardant is a bromine-containing flame retardant; the auxiliary flame retardant is an antimony-containing flame retardant; the laser marking white additive is a mixture of a fluorescent whitening agent and an inorganic salt; the inorganic salt includes carbonates and / or phosphates; and the other functional additives include antioxidants, heat stabilizers and polytetrafluoroethylene.

2. The bromine-antimony type flame-retardant reinforced polyester composite material according to claim 1, characterized in that: The fluorescent whitening agent is selected from one or more of 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, 4,4′-bis(2-benzoxazolyl)stilbene, 4,4-bis(2-dimethoxyphenylvinyl)biphenyl, and 1,4-bis(benzoxazolyl-2-yl)naphthalene; the inorganic salt is selected from one or more of sodium carbonate, sodium bicarbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, or trisodium phosphate; Preferably, the weight ratio of the fluorescent whitening agent to the inorganic salt is 1:3 to 3:

1.

3. The bromine-antimony flame-retardant reinforced polyester composite material according to claim 1 or 2, characterized in that: The antioxidant is a compound of a hindered phenol antioxidant and a phosphite antioxidant; the heat stabilizer is selected from one or more of metal soap compounds, organic tin compounds, organic antimony compounds, epoxy compounds, phosphite compounds, polyol compounds or diphenylthiourea compounds; the weight average molecular weight of the polytetrafluoroethylene is 4 to 5 million; Preferably, the antioxidant accounts for 0.3-0.6% of the total weight of the bromine-antimony type flame retardant reinforced polyester composite material; the heat stabilizer accounts for 0.1-0.4% of the total weight of the bromine-antimony type flame retardant reinforced polyester composite material; and the polytetrafluoroethylene accounts for 0.15-0.3% of the total weight of the bromine-antimony type flame retardant reinforced polyester composite material.

4. The bromine-antimony type flame-retardant reinforced polyester composite material according to any one of claims 1 to 3, characterized in that: The main flame retardant is one or more of brominated polystyrene, brominated epoxy resin, brominated polycarbonate, decabromodiphenylethane, and brominated triazine; And / or, the auxiliary flame retardant is an antimony-containing compound; preferably, the antimony-containing compound is one or both of antimony trioxide or sodium antimonate.

5. The bromine-antimony type flame-retardant reinforced polyester composite material according to claim 1, characterized in that: The viscosity of the polyethylene terephthalate resin is 0.5-1.1 dl / g.

6. The bromine-antimony type flame-retardant reinforced polyester composite material according to claim 1, characterized in that: The crystallization accelerator is one or more of polycaprolactone and its end-capped compounds, polyethylene glycol and its end-capped compounds, polypropylene glycol and its end-capped compounds, polyolefins, modified polyolefins or polyamides; And / or, the nucleating agent is selected from one or more of an organic nucleating agent and an inorganic nucleating agent.

7. The bromine-antimony type flame-retardant reinforced polyester composite material according to claim 1, characterized in that: According to parts by weight, it includes the following components: 33.0-50.0 parts of polyethylene terephthalate resin; Main flame retardant 10.0~13.0 parts; Auxiliary flame retardant 4.0~5.0 parts; 1.0~2.0 parts of toughening agent; Crystallization accelerator 0.5~1.0 part; Nucleating agent 0.5~2 parts; Laser marking white additive 0.05~0.2 parts; Carbon black 0.3~1.0 part; Glass fiber 30.0~45.0 parts; Lubricant 0.2~1 part; Other functional additives 0.8~1.1 parts.

8. The bromine-antimony type flame-retardant reinforced polyester composite material according to claim 1, characterized in that: The carbon black is a medium pigment carbon black with a particle size of 18-25nm; And / or, the toughening agent is one or more of ethylene-methyl acrylate, ethylene-ethyl acrylate, ethylene-butyl acrylate, low-density polyethylene, ethylene-methyl acrylate-glycidyl ester, ethylene-ethyl acrylate-glycidyl ester, ethylene-butyl acrylate-glycidyl ester, maleic anhydride grafted ethylene-octene copolymer or polyethylene copolymer; And / or, the glass fiber is an alkali-free glass fiber; the diameter of the glass fiber is 9-25um; And / or, the lubricant is one or more of montanic acid esters and their derivatives, pentaerythritol stearate, oxidized PE wax, amide wax, zinc stearate, calcium stearate or silicone.

9. The method for preparing the bromine-antimony type flame-retardant reinforced polyester composite material according to any one of claims 1 to 8, characterized in that: The steps include: Mixing polyethylene terephthalate resin, a main flame retardant, an auxiliary flame retardant, a toughening agent, a crystallization accelerator, a nucleating agent, a laser marking white additive, carbon black, a lubricant and other functional additives to obtain a premix; The premix is ​​mixed with glass fiber and then extruded, drawn into strips, cooled, dried and granulated; wherein the extrusion temperature is 240-280° C. and the rotation speed is 250-600 rpm.

10. Use of the bromine-antimony type flame retardant reinforced polyester composite material according to any one of claims 1 to 8 or the bromine-antimony type flame retardant reinforced polyester composite material prepared according to the preparation method of claim 9 in electronic components.

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