High-CTI flame-retardant PBT material and preparation method thereof

Abstract

The invention discloses a high-CTI (comparative tracking index) flame-retardant PBT (polybutylene terephthalate) material and a preparation method thereof, and relates to the technical field of engineering plastics. The high-CTI flame-retardant PBT material disclosed by the invention is prepared from the following raw material components in parts by weight: 100 parts by mass of PBT, 16 to 24 parts by mass of compound flame retardant, 1 to 2 parts by mass of laser carving color master batch, 0.9 to 1.1 parts by mass of compatilizer, 9 to 11 parts by mass of glass fiber, 9 to 11 parts by mass of reinforcing filling aid and 0.2 to 0.3 part by mass of antioxidant, the compound flame retardant comprises the following raw material components in parts by weight: 16 parts by mass of modified brominated epoxy resin, 7-9 parts by mass of an MCA flame retardant and 6-8 parts by mass of antimony trioxide; the reinforcing filling auxiliary agent is pentaerythritol modified mica or pentaerythritol modified talcum powder; the modified brominated epoxy resin is obtained by modifying epoxy resin with phosphorus oxychloride.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engineering plastics, in particular to a high-CTI flame-retardant PBT material and a preparation method thereof. BACKGROUND

[0002] With the increasing environmental protection supervision of the state on production enterprises, and the changes in raw materials and market demand of modified plastics industry, domestic manufacturers are actively developing green, energy-saving and environmentally friendly products. Under the promotion of the transformation of the electrical industry, the demand for laser engraving and marking in the modified plastics industry is increasingly prominent, and it is gradually favored by the market. Laser marking technology has begun to gradually replace traditional ink printing methods in recent years due to its environmental protection, high efficiency and durable marking characteristics. With the progress of technology research and development and the wide popularity of laser printing technology, it is expected that in the next 2 to 5 years, laser marking technology will basically replace traditional ink printing in the modified plastics industry.

[0003] Polybutylene terephthalate (PBT) is a thermoplastic with high crystallinity and crystallization rate, which is widely used in laser marking materials due to its excellent processing performance. However, PBT has weak absorption ability to laser, and usually requires high laser power and low laser speed to form clear marks. Current laser marking technology often has poor marking effect, blurred patterns, and yellowing of the writing when processing PBT. To improve the effect of PBT laser marking, laser engraving special color masterbatch is usually added to modified PBT plastics to improve its performance.

[0004] In addition, PBT also needs to meet the UL 94 V0 fire retardant grade standard during use, and can not burn under the contact of a 750℃ hot wire, while having a high relative tracking index. Glass fiber reinforced PBT material not only has high strength, good fatigue resistance, dimensional stability, and small creep and excellent aging resistance, but also has excellent electrical performance, such as high volume resistivity, dielectric strength, and arc resistance, which can maintain stable performance even in humid and high temperature environments, so it is an ideal choice for manufacturing electronic and electrical components. Currently, bromine-containing organic compounds (mainly brominated epoxy resin) and antimony trioxide are mainly used as flame retardants in flame-retardant reinforced PBT materials.

[0005] In order to make PBT material have high CTI value, generally, halogen-free flame retardant system is used to achieve this goal. However, the high CTI flame-retardant reinforced PBT composite material made by using halogen-free flame retardant system has high cost, and compared with the commonly used bromine-containing flame retardant system, the addition amount of halogen-free system is larger, which can cause the mechanical properties of the material to decrease, thereby possibly causing the problem of product cracking or brittle cracking; and the free bromine in the bromine-containing flame retardant system can make the relative tracking index of the material be low, generally in the range of CTI 175 to CTI 225, and the glowing wire ignition temperature can only reach 725℃ at most. However, the relative tracking index of the electronic component material used in unattended white household appliances must reach or exceed CTI 250, which seriously limits the application of ordinary bromine-containing flame-retardant reinforced PBT composite material.

[0006] Therefore, the applicant prepares a high CTI flame-retardant PBT material to solve the above problems. SUMMARY

[0007] In order to solve the existing technical problems, the application provides a high CTI flame-retardant PBT material, and the raw material components include, by weight fraction, 100 parts by mass of PBT, 16 to 24 parts by mass of a compounded flame retardant, 1 to 2 parts by mass of a laser engraving color master batch, 0.9 to 1.1 parts by mass of a compatibilizer, 9 to 11 parts by mass of glass fiber, 9 to 11 parts by mass of a reinforcing filling aid, and 0.2 to 0.3 parts by mass of an antioxidant.

[0008] Further, the compounded flame retardant includes, by weight fraction, 16 parts by mass of a modified brominated epoxy resin, 7 to 9 parts by mass of MCA flame retardant, and 6 to 8 parts by mass of antimony trioxide.

[0009] Further, the modified brominated epoxy resin is obtained by modifying an epoxy resin with phosphorus oxychloride.

[0010] Further, the particle size of the antimony trioxide is less than 0.4 μm.

[0011] Further, the compatibilizer is an amide wax.

[0012] Further, the reinforcing filling aid is pentaerythritol modified mica or pentaerythritol modified talc.

[0013] Further, the antioxidant is any one or both of antioxidant 1010 and antioxidant 168.

[0014] The application also provides a preparation method of the high CTI flame-retardant PBT material, including the following steps: (1) batching: the raw material components and the proportioning according to any one of claims 1 to 6 are weighed and batched; (2) Premixing: the reinforcing filler aid weighed in step (1) is added to the modified brominated epoxy resin, stirred and dispersed at 1200-1800 rpm for 10-30 min, then heated to 80°C, stirred and reacted, after 1.8-2.2 h of reaction, heated to 110°C, stirred and reacted overnight at 1300-1700 rpm until substantially no hydrogen chloride gas is generated, and then cooled to room temperature to obtain a premix; (3) Preparation of the high-CTI flame-retardant PBT material: the PBT is dried in a blast oven at 140°C for 3-5 h, the premix and the remaining raw material components weighed in step (1) are mixed uniformly, then the obtained composite material is granulated by a twin-screw extruder and molded into a high-CTI flame-retardant PBT material by an injection molding machine.

[0015] Further, the modified brominated epoxy resin is prepared by the following method: aluminum chloride catalyst is added to phosphorus oxychloride, stirred until the catalyst is dissolved, then brominated epoxy resin is added dropwise at 64-66°C, the reaction temperature is maintained at 60-70°C, after the addition of the brominated epoxy resin is completed, the reaction is continued at 80°C for 1.5 h to obtain the modified brominated epoxy resin; the mass ratio of the phosphorus oxychloride to the aluminum chloride catalyst is 1:0.003-0.005; the amount of substance of the phosphorus oxychloride is 0.9-1.1 times the amount of substance of the hydroxyl and epoxy groups in the brominated epoxy resin.

[0016] Further, the reinforcing filler aid is prepared by the following method: silane coupling agent KH-550 is dissolved in 94 times the mass of anhydrous ethanol, stirred with a glass rod until the solution is mixed uniformly, then dried sericite powder or talc powder is added, the mass ratio of the sericite powder or talc powder to the silane coupling agent KH-550 is 100:1, stirred with a glass rod for 5-15 min, then ultrasonically dispersed at 50°C for 40-60 min to fully wet the surface of the sericite powder or talc powder with the silane coupling agent, after ultrasonic dispersion, the excess solution is filtered off by a vacuum pump, then the sericite powder or talc powder treated with the silane coupling agent after filtration is dried in a blast drying oven at 100°C for 6 h, then placed in benzene in an amount of 80-100 times the mass of the sericite powder or talc powder, and an equal molar amount of terephthalic acid is added, heated to 85-95°C, stirred and ultrasonicated for 1-2 h, filtered, washed with acetone and deionized water for 2-4 times in sequence, and dried in an oven at 80°C for 48 h, then dispersed in toluene in an amount of 20-40 times the mass of the sericite powder or talc powder, and 0.5-0.6 times the amount of substance of the pentaerythritol is added, stirred at 300-500 rpm for 20-40 min, then 0.6-0.8 times the mass of concentrated sulfuric acid is added, heated to reflux for 2-4 h, filtered, washed with acetone and deionized water for 2-4 times in sequence, and dried in an oven at 80°C for 48 h to obtain the reinforcing filler aid.

[0017] Further, the temperature of each section of the double screw extruder is in turn: 250 DEG C, 245 DEG C, 240 DEG C, 235 DEG C, 230 DEG C, 225 DEG C, 230 DEG C, 235 DEG C, 240 DEG C, 245 DEG C, and the screw rotation speed is: 300 r / min; the injection molding conditions are: the temperature of each section of the injection molding machine is in turn: 250 DEG C, 250 DEG C, 250 DEG C, 250 DEG C, 230 DEG C.

[0018] Compared with the prior art, the present application has the following advantages: (1) The high-CTI flame-retardant PBT material of the present application adopts PBT, a compounded flame retardant, laser engraving color masterbatch, a compatibilizer, glass fiber, reinforcing and filling additives, and an antioxidant for blending extrusion granulation and injection molding, and the prepared high-CTI flame-retardant PBT material has a high CTI value, good laser marking effect, flame-retardant performance, processing performance, and mechanical performance, and meets the requirement of not catching fire for 750 DEG C hot wire contact materials.

[0019] (2) The high-CTI flame-retardant PBT material of the present application adopts 1-2 parts by mass of black laser engraving color masterbatch, which can effectively reduce the reflectivity of PBT and increase the absorbance of PBT in the 960-1200 nm wave band range, thereby improving the light-heat conversion efficiency of PBT, and further causing PBT to exhibit melting, foaming, and ablation phenomena under laser engraving, and having good laser marking effect.

[0020] (3) The compatibilizer of the present application adopts amide wax, which has a high melting point and maintains low viscosity in a molten state, and in a high-temperature molten state, the PBT, glass fiber, and compounded flame retardant have good compatibility.

[0021] (4) The compounded flame retardant of the present application adopts modified brominated epoxy resin, MCA flame retardant, and antimony trioxide, wherein the modified brominated epoxy resin is obtained by reacting phosphorus oxychloride with epoxy groups and hydroxyl groups on the brominated epoxy resin to obtain dichlorophosphate, thereby enhancing the flame retardance of the modified brominated epoxy resin; meanwhile, the modified brominated epoxy resin is compounded with antimony trioxide, and at high temperature, antimony trioxide can react with hydrogen bromide generated by the decomposition of brominated epoxy resin to generate antimony tribromide or antimony oxybromide, antimony tribromide can effectively capture active free radicals in the gas phase, change the reaction mode in the combustion gas phase, reduce the heat released by the reaction, effectively inhibit the combustion reaction, and make the flame extinguish, at the same time, antimony tribromide slowly releases halogen radicals during the decomposition process, which can combine with active free radicals in the air, can maintain a low concentration of active free radicals for a long time, greatly prolongs the life of the free radical trapping agent in the flame zone, and makes the brominated epoxy resin and antimony trioxide synergistically act to enhance the flame retardant performance of the compounded flame retardant; the addition of antimony trioxide and MCA flame retardant not only has the effect of flame retardation, but also can ensure high hot wire.

[0022] (5) The reinforcing and filling aid agent of the present application adopts pentaerythritol modified mica or pentaerythritol modified talc powder. The talc powder and mica powder can play a role in absorbing the conductive polar particles generated by the flame retardant. The talc powder and mica powder have the effect of making the positive and negative ions generated by the polar particles and their hydrolysis ionization into relatively stable compounds that are not easy to ionize. In this way, the possibility of generating a current path on the surface of the material is greatly reduced, thereby improving the electrical leakage resistance of the material. However, the compatibility of talc powder and mica powder with PBT is poor. The present application modifies the talc powder and mica powder with pentaerythritol, which can effectively improve the compatibility of talc powder and mica powder in PBT, and the processing performance and mechanical properties of the prepared high-CTI flame-retardant PBT material are good. At the same time, during the preparation of the high-CTI flame-retardant PBT material, the pentaerythritol on the reinforcing and filling aid agent reacts with the modified brominated epoxy resin in the compounded flame retardant. The hydroxyl group of pentaerythritol reacts with the chlorine of dichlorophosphate to form a pentaerythritol phosphate derivative, which stably attaches the talc powder or mica powder to the compounded flame retardant. In this way, not only is the compatibility problem between the talc powder and mica powder and the compounded flame retardant improved, but also the molecular chains of the modified brominated epoxy resin in the compounded flame retardant and the PBT molecular chains are entangled together with the talc powder or mica powder as an irrational node, thereby enhancing the mechanical properties of the high-CTI flame-retardant PBT material. DETAILED DESCRIPTION

[0023] The present application will be further described in detail below in conjunction with examples, but the following examples should not be construed as limiting the present application.

[0024] The sources of some raw materials in the examples and comparative examples of the present application are as follows: PBT: 1100-211M, Changchun Chemical Industry Group Co., Ltd. of Taiwan, China; Sericite powder (brand CF-A3), Qingdao Yousuo Chemical Technology Co., Ltd.; Brominated epoxy resin: EP-10000 from Shandong Tianyi Chemical Co., Ltd.; Glass fiber: T635B, Taishan Glass Fiber Co., Ltd.; Laser engraving color masterbatch: black color masterbatch RF2030C produced by Guangzhou Runfeng Chemical Co., Ltd., pigment carbon black, carrier resin PBT; Compatibilizer: amide wax, commercially available; Antioxidant: antioxidant 168, commercially available; Antimony trioxide: industrial grade, Guangxi Huaxin Chemical Co., Ltd., particle size 0.4 μm. Example 1

[0025] A method for preparing a high-CTI flame-retardant PBT material, the preparation steps are as follows: (1) Ingredients: 100 parts by mass of PBT, 16 parts by mass of a compounded flame retardant, 1 part by mass of a laser engraving color master batch, 0.9 parts by mass of a compatibilizer, 9 parts by mass of glass fiber, 9 parts by mass of a reinforcing filler, and 0.2 parts by mass of an antioxidant; the compounded flame retardant is compounded from 16 parts by mass of modified brominated epoxy resin, 7 parts by mass of MCA flame retardant, and 6 parts by mass of antimony trioxide; (2) Pre-mixing: the reinforcing filler weighed in step (1) is added to the modified brominated epoxy resin, stirred and dispersed at 1200 rpm for 10 min, then heated to 80°C, stirred and reacted, reacted for 1.8 h, then heated to 110°C, stirred and reacted at 1300 rpm overnight until substantially no hydrogen chloride gas is generated, and then cooled to room temperature to obtain a pre-mixed material; (3) Preparation of high-CTI flame-retardant PBT material: the PBT is dried in a blast oven at 140°C for 3 h, the pre-mixed material and the remaining ingredients weighed in step (1) are mixed uniformly, then compounded by a twin-screw extruder, and the obtained composite material is injection molded in an injection molding machine to obtain a high-CTI flame-retardant PBT material; wherein the temperature of each section of the twin-screw extruder is 250°C, 245°C, 240°C, 235°C, 230°C, 225°C, 230°C, 235°C, 240°C, 245°C, and the screw rotation speed is 300 r / min; the temperature of each section of the injection molding machine is 250°C, 250°C, 250°C, 250°C, and 230°C.

[0026] The preparation method of the modified brominated epoxy resin is as follows: aluminum chloride catalyst is added to phosphorus oxychloride, stirred until the catalyst is dissolved, then brominated epoxy resin is added dropwise at 64°C, the reaction temperature is maintained at 60°C, after the dropwise addition of the brominated epoxy resin is completed, the temperature is continued to be maintained at 80°C for 1.5 hours to obtain the modified brominated epoxy resin; the mass ratio of the phosphorus oxychloride to the aluminum chloride catalyst is 1:0.003; the amount of substance of the phosphorus oxychloride is 0.9 times the amount of substance of the hydroxyl and epoxy groups in the brominated epoxy resin.

[0027] The preparation method of the reinforcing filling aid is as follows: the silane coupling agent KH-550 is dissolved in 94 times of anhydrous ethanol by mass, and the solution is stirred with a glass rod until the mixture is uniform. Then, the dried sericite powder is added, and the mass ratio of the sericite powder to the silane coupling agent KH-550 is 100:1. The mixture is stirred with a glass rod for 5 min, and then ultrasonic dispersion is performed at 50℃ for 40 min to fully wet the surface of the sericite powder with the silane coupling agent. After ultrasonic dispersion, the excess solution is filtered out using a vacuum pump. Then, the sericite powder treated with the silane coupling agent is dried in a forced air drying oven at 100℃ for 6 hours. Then, the sericite powder is placed in benzene with a mass of 80 times that of the sericite powder, and an equal molar amount of terephthalic acid is added. The temperature is raised to 85℃, and the mixture is stirred and ultrasonically dispersed for 1 h. The mixture is filtered and washed with acetone and deionized water twice. The mixture is dried in an oven at 80℃ for 48 h. Then, the mixture is dispersed in toluene with a mass of 20 times that of the sericite powder, and 0.5 times the amount of pentaerythritol by mass is added. The mixture is stirred at 300 rpm for 20 min. Then, 0.6 times the amount of concentrated sulfuric acid by mass is added, and the mixture is heated and refluxed for 2 h. The mixture is filtered and washed with acetone and deionized water twice. The mixture is dried in an oven at 80℃ for 48 h to obtain the reinforcing filling aid. Example 2

[0028] A preparation method of a high-CTI flame-retardant PBT material, the preparation steps are as follows: (1) ingredient: 100 parts by mass of PBT, 20 parts by mass of a compounded flame retardant, 1.5 parts by mass of a laser engraving color master batch, 1 part by mass of a compatibilizer, 10 parts by mass of glass fiber, 10 parts by mass of a reinforcing filling aid, and 0.25 parts by mass of an antioxidant; the compounded flame retardant is compounded from the following raw material components: 16 parts by mass of a modified brominated epoxy resin, 8 parts by mass of MCA flame retardant, and 7 parts by mass of antimony trioxide; (2) pre-mixing: the reinforcing filling aid weighed in step (1) is added to the modified brominated epoxy resin, and stirred and dispersed at 1500 rpm for 20 min. Then, the temperature is raised to 80℃, and the mixture is stirred and reacted for 2 h. Then, the temperature is raised to 110℃, and the mixture is stirred and reacted overnight until substantially no hydrogen chloride gas is generated. Then, the mixture is cooled to room temperature to obtain a pre-mixed material; (3) preparation of a high-CTI flame-retardant PBT material: the PBT is dried in a forced air oven at 140℃ for 4 h. The pre-mixed material and the remaining raw material components weighed in step (1) are mixed uniformly. Then, the mixture is blended and pelletized in a twin-screw extruder, and the obtained composite material is injection molded in an injection molding machine to obtain a high-CTI flame-retardant PBT material. The temperature of each section of the twin-screw extruder is 250℃, 245℃, 240℃, 235℃, 230℃, 225℃, 230℃, 235℃, 240℃, and 245℃, respectively, and the screw rotation speed is 300 r / min. The temperature of each section of the injection molding machine is 250℃, 250℃, 250℃, 250℃, and 230℃, respectively.

[0029] The preparation method of the modified brominated epoxy resin is as follows: aluminum chloride catalyst is added into phosphorus oxychloride, after stirring until the catalyst is dissolved, brominated epoxy resin is added dropwise at 65°C, the reaction temperature is kept at 65°C, after the dropwise addition of the brominated epoxy resin is completed, the reaction is continued at 80°C for 1.5 hours, and the modified brominated epoxy resin is obtained; the mass ratio of the phosphorus oxychloride to the aluminum chloride catalyst is 1:0.004; the amount of substance of the phosphorus oxychloride is 1 times the amount of substance of the hydroxyl and epoxy groups in the brominated epoxy resin.

[0030] The preparation method of the reinforcing and filling aid is as follows: the silane coupling agent KH-550 is dissolved in 94 times the mass of anhydrous ethanol, the solution is stirred with a glass rod until it is uniformly mixed, then the dried sericite powder is added, the mass ratio of the sericite powder to the silane coupling agent KH-550 is 100:1, the mixture is stirred with a glass rod for 10 min, then the surface of the sericite powder is fully wetted with the silane coupling agent by ultrasonic dispersion at 50°C for 50 min, after the ultrasonic dispersion is completed, the excess solution is filtered out using a vacuum pump, then the sericite powder treated with the silane coupling agent after filtration is dried in a forced air drying oven at 100°C for 6 hours, then the sericite powder is placed in benzene with a mass of 90 times the mass of the sericite powder, and an equal molar amount of terephthalic acid is added, the temperature is raised to 90°C, and the mixture is stirred and ultrasonically dispersed for 1.5 h, then the mixture is filtered and washed with acetone and deionized water three times in sequence, and then the mixture is dried in an oven at 80°C for 48 h, then the mixture is dispersed in toluene with a mass of 30 times the mass of the sericite powder, an amount of 0.55 times the amount of substance of the pentaerythritol is added, and the mixture is stirred at 400 rpm for 30 min, then an amount of 0.7 times the mass of the pentaerythritol is added in the form of concentrated sulfuric acid, the mixture is heated to reflux for 3 h, then the mixture is filtered and washed with acetone and deionized water three times in sequence, and then the mixture is dried in an oven at 80°C for 48 h, and the reinforcing and filling aid is obtained. Example 3

[0031] A preparation method of a high-CTI flame-retardant PBT material, the preparation steps are as follows: (1) batching: 100 parts by mass of PBT, 24 parts by mass of a compounded flame retardant, 2 parts by mass of a laser engraving color master batch, 1.1 parts by mass of a compatibilizer, 11 parts by mass of glass fiber, 11 parts by mass of a reinforcing and filling aid, and 0.3 parts by mass of an antioxidant; the compounded flame retardant is prepared by batching the following raw material components: 16 parts by mass of a modified brominated epoxy resin, 9 parts by mass of MCA flame retardant, and 8 parts by mass of antimony trioxide; (2) premixing: the reinforcing and filling aid weighed in step (1) is added to the modified brominated epoxy resin, and the mixture is stirred and dispersed at 1800 rpm for 30 min, then the temperature is raised to 80°C, the mixture is stirred and reacted for 2.2 h, then the temperature is raised to 110°C, the mixture is stirred and reacted overnight until substantially no hydrogen chloride gas is generated, and then the mixture is cooled to room temperature, and a premix is obtained; (3) Preparation of high-CTI flame-retardant PBT material: PBT is dried in a blast oven at 140°C for 5h, and the premix, the remaining raw material components weighed in step (1) are mixed uniformly, then the obtained composite material is molded into high-CTI flame-retardant PBT material by blending and granulating in a twin-screw extruder and injection molding in an injection molding machine; wherein the temperature of each section of the twin-screw extruder is 250°C, 245°C, 240°C, 235°C, 230°C, 225°C, 230°C, 235°C, 240°C, 245°C, respectively, and the screw rotation speed is 300r / min; the temperature of each section of the injection molding machine is 250°C, 250°C, 250°C, 250°C, 230°C, respectively.

[0032] The preparation method of the modified brominated epoxy resin is as follows: aluminum chloride catalyst is added to phosphorus oxychloride, after stirring until the catalyst is dissolved, brominated epoxy resin is added dropwise at 66°C, the reaction temperature is maintained at 70°C, after the dropwise addition of brominated epoxy resin is completed, the reaction is continued at 80°C for 1.5 hours to obtain the modified brominated epoxy resin; the mass ratio of phosphorus oxychloride to aluminum chloride catalyst is 1:0.005; the amount of substance of phosphorus oxychloride is 1.1 times the amount of substance of hydroxyl and epoxy groups in the brominated epoxy resin.

[0033] The preparation method of the reinforcing and filling aid is as follows: silane coupling agent KH-550 is dissolved in 94 times its mass of anhydrous ethanol, and stirred with a glass rod until the solution is uniformly mixed, then dried sericite powder is added, the mass ratio of sericite powder to silane coupling agent KH-550 is 100:1, and stirred with a glass rod for 15min, then ultrasonic dispersion is carried out at 50°C for 60min to fully wet the surface of the sericite powder with the silane coupling agent, after ultrasonic dispersion is completed, the excess solution is filtered out using a vacuum pump, and then the filtered sericite powder treated with the silane coupling agent is dried in a blast drying oven at 100°C for 6 hours, then it is placed in benzene with a mass of 100 times that of the sericite powder, and an equal molar amount of terephthalic acid is added, the temperature is raised to 95°C, and stirring is carried out while ultrasonic dispersion for 2h, then it is filtered and washed with acetone and deionized water four times in turn, and then dried in an oven at 80°C for 48h, then it is dispersed in toluene with a mass of 40 times that of the sericite powder, and an amount of substance of 0.6 times that of KH550 is added as pentaerythritol, and stirred at 500rpm for 40min, then an amount of 0.8 times that of the pentaerythritol is added as concentrated sulfuric acid, and heated to reflux for 4h, then filtered and washed with acetone and deionized water four times in turn, and then dried in an oven at 80°C for 48h to obtain the reinforcing and filling aid.

[0034] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that only PBT, compounded flame retardant, compatibilizer, glass fiber, reinforcing and filling aid, and antioxidant are used to prepare the high-CTI flame-retardant PBT material; the remaining steps and components are the same as those of Example 2.

[0035] Comparative Example 2 Comparative Example 2 differs from Example 2 only in that high CTI flame-retardant PBT material is prepared by using only PBT, compounded flame retardant, laser engraving color masterbatch, glass fiber, reinforcing filler aid, antioxidant; the rest of the steps and ingredients are the same as Example 2.

[0036] Comparative Example 3 Comparative Example 3 differs from Example 2 only in that high CTI flame-retardant PBT material is prepared by using only PBT, modified brominated epoxy resin, laser engraving color masterbatch, compatibilizer, glass fiber, reinforcing filler aid, antioxidant; the rest of the steps and ingredients are the same as Example 2.

[0037] Comparative Example 4 Comparative Example 4 differs from Example 2 only in that compounded flame retardant is prepared by using brominated epoxy resin, MCA flame retardant, antimony trioxide; the rest of the steps and ingredients are the same as Example 2.

[0038] Comparative Example 5 Comparative Example 5 differs from Example 2 only in that compounded flame retardant is prepared by using modified brominated epoxy resin, antimony trioxide; the rest of the steps and ingredients are the same as Example 2.

[0039] Comparative Example 6 Comparative Example 6 differs from Example 2 only in that compounded flame retardant is prepared by using brominated epoxy resin, MCA flame retardant; the rest of the steps and ingredients are the same as Example 2.

[0040] Comparative Example 7 Comparative Example 7 differs from Example 2 only in that reinforcing filler aid is prepared by using sericite powder; the rest of the steps and ingredients are the same as Example 2.

[0041] Effect Example Processability: observe whether the surface of the high CTI flame-retardant PBT material prepared by the examples and comparative examples is smooth; Laser marking effect: use a Nd:YAG laser marking machine to laser mark the high CTI flame-retardant PBT material prepared by the examples and comparative examples, and set the laser marking scanning rate to 500-3000 mm / s; Flame retardancy: flame retardant performance is detected according to UL 94 vertical burning method in GB / T 2408-1996; Mechanical properties: the high CTI flame-retardant PBT material prepared by the examples and comparative examples is detected according to ISO527, the test rate is 5 mm / min, the tensile strength is tested; according to ISO178, the test rate is 2 mm / min, the bending strength is tested; Hot wire temperature: the high-CTI flame-retardant PBT material prepared in the examples and the comparative examples was detected for hot wire temperature according to IEC 60695-2-12-2000; CTI value: the high-CTI flame-retardant PBT material prepared in the examples and the comparative examples was tested for CTI value according to GB / T 4207-2003.

[0042] The following Table 1 shows the test results of various properties of the high-CTI flame-retardant PBT material prepared in the examples 1-3 and the comparative examples 1-7 of the present application.

[0043] Table 1 Smoothness of surface Laser marking effect Hot wire temperature UL94 (1.6 mm) Tensile strength (MPa) Flexural strength (MPa) CTI value / V Example 1 Smooth Good Non-flaming at 750°C V-0 115 153 600 Example 2 Smooth Good Non-flaming at 750°C V-0 116 154 600 Example 3 Smooth Good Non-flaming at 750°C V-0 109 143 600 Comparative Example 1 Smooth Poor Non-flaming at 750°C V-0 113 149 600 Comparative Example 2 Not smooth Good Non-flaming at 750°C V-0 70 105 600 Comparative Example 3 Smooth Good Flaming at 750°C HB 65 95 600 Comparative Example 4 Not smooth Good Non-flaming at 750°C V-1 100 126 550 Comparative Example 5 Not smooth Good Flaming at 750°C V-2 98 123 600 Comparative Example 6 Smooth Good Flaming at 750°C V-1 110 145 600 Comparative Example 7 Not smooth Good Non-flaming at 750°C V-1 60 92 525 It can be found from Table 1 that the high-CTI flame-retardant PBT material prepared in the examples has a high CTI value, good laser marking effect, flame-retardant property, processing property and mechanical property, and meets the requirement that the material does not catch fire when contacted by a 750℃ hot wire; compared with example 2, the high-CTI flame-retardant PBT material prepared by adding laser engraving color master batch in comparative example 1 has a better laser marking effect, clear font and dark character color; compared with example 2, the high-CTI flame-retardant PBT material added with a compatilizer in comparative example 2 has good processing property and mechanical property; compared with example 2, the high-CTI flame-retardant PBT material prepared by using modified brominated epoxy resin, MCA flame retardant and antimony trioxide in comparative examples 3-6 has a high CTI value, good flame-retardant property, processing property and mechanical property, and meets the requirement that the material does not catch fire when contacted by a 750℃ hot wire; compared with example 2, the high-CTI flame-retardant PBT material prepared by using pentaerythritol modified mica as a reinforcing and filling agent in comparative example 7 has a high CTI value, good flame-retardant property, processing property and mechanical property.

[0044] In addition, it should be noted that each specific technical feature described in the foregoing embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present application will not describe various possible combinations again.

Claims

1. A high CTI flame-retardant PBT material, characterized in that, By weight, the raw material components include: 100 parts by weight of PBT, 16-24 parts by weight of compound flame retardant, 1-2 parts by weight of laser engraving masterbatch, 0.9-1.1 parts by weight of compatibilizer, 9-11 parts by weight of glass fiber, 9-11 parts by weight of reinforcing filler, and 0.2-0.3 parts by weight of antioxidant.

2. The high CTI flame-retardant PBT material according to claim 1, characterized in that, The compound flame retardant comprises, by weight, 16 parts modified brominated epoxy resin, 7-9 parts MCA flame retardant, and 6-8 parts antimony trioxide.

3. The high CTI flame-retardant PBT material according to claim 2, characterized in that, The modified brominated epoxy resin is obtained by modifying epoxy resin with phosphorus oxychloride.

4. The high CTI flame-retardant PBT material according to claim 1, characterized in that, The compatibilizer is an amide wax.

5. The high CTI flame-retardant PBT material according to claim 1, characterized in that, The reinforcing filler is pentaerythritol-modified mica or pentaerythritol-modified talc.

6. The high CTI flame-retardant PBT material according to claim 1, characterized in that, The antioxidant is any one or two of antioxidant 1010 and antioxidant 168.

7. A method for preparing a high CTI flame-retardant PBT material, characterized in that, Includes the following steps: (1) Ingredients: The raw material components and proportions described in any one of claims 1 to 6 are weighed and prepared; (2) Premixing: Add the reinforcing filler weighed in step (1) to the modified brominated epoxy resin, stir and disperse at 1200~1800 rpm for 10~30 min, then heat to 80℃, stir and react for 1.8~2.2 h, then heat to 110℃, stir and react overnight at 1300~1700 rpm until there is basically no hydrogen chloride gas produced, and then cool to room temperature to obtain the premix. (3) Preparation of high CTI flame retardant PBT material: PBT is dried in a forced-air oven at 140°C for 3-5 hours. The premix and the raw material components weighed in the remaining step (1) are mixed evenly and then granulated by a twin-screw extruder. At the same time, the resulting composite material is injection molded in an injection molding machine to obtain high CTI flame retardant PBT material.

8. The method for preparing the high CTI flame-retardant PBT material according to claim 7, characterized in that, The modified brominated epoxy resin is prepared as follows: Aluminum trichloride catalyst is added to phosphorus oxychloride and stirred until dissolved. Brominated epoxy resin is then added dropwise at 64-66°C, maintaining the reaction temperature at 60-70°C. After the addition of the brominated epoxy resin is complete, the reaction is continued at 80°C for 1.5 hours to obtain the modified brominated epoxy resin. The mass ratio of phosphorus oxychloride to aluminum trichloride catalyst is 1:0.003-0.

005. The amount of phosphorus oxychloride is 0.9-1.1 times the amount of hydroxyl and epoxy groups in the brominated epoxy resin.

9. The method for preparing the high CTI flame-retardant PBT material according to claim 7, characterized in that, The preparation method of the reinforcing filler is as follows: Dissolve silane coupling agent KH-550 in anhydrous ethanol at 94 times its mass, stir with a glass rod until the solution is uniformly mixed, then add dried sericite powder or talc powder, with a mass ratio of sericite powder or talc powder to silane coupling agent KH-550 of 100:1, stir with a glass rod for 5-15 minutes, then ultrasonically disperse at 50°C for 40-60 minutes to ensure the silane coupling agent fully wets the surface of the sericite powder or talc powder. After ultrasonication, use a vacuum pump to filter out excess solution, then dry the filtered sericite powder or talc powder treated with silane coupling agent in a forced-air drying oven at 100°C for 6 hours, and then add sericite powder or talc powder. Add 80-100 times the mass of benzene and an equimolar amount of terephthalic acid (KH550), heat to 85-95℃, and stir while sonicating for 1-2 hours. Filter, wash 2-4 times with acetone and deionized water, and dry in an 80℃ oven for 48 hours. Then disperse in 20-40 times the mass of sericite powder or talc powder in toluene, add 0.5-0.6 times the molar amount of pentaerythritol (KH550), stir at 300-500 rpm for 20-40 minutes, then add 0.6-0.8 times the mass of concentrated sulfuric acid (pentaerythritol), heat under reflux for 2-4 hours, filter, wash 2-4 times with acetone and deionized water, and dry in an 80℃ oven for 48 hours to obtain the reinforcing filler.

10. The method for preparing the high CTI flame-retardant PBT material according to claim 7, characterized in that, The temperatures of each section of the twin-screw extruder are, in sequence: 250℃, 245℃, 240℃, 235℃, 230℃, 225℃, 230℃, 235℃, 240℃, 245℃; the screw speed is 300 r / min. The injection molding conditions are: the temperatures of each section of the injection molding machine are, in sequence: 250℃, 250℃, 250℃, 230℃.