Pbt-based composite material and method for producing the same

Abstract

This invention relates to a PBT-based composite material and its preparation method. The PBT-based composite material comprises, by weight, the following components: 40-55 parts PBT resin; 5-10 parts PET resin; 28-32 parts alkali-free glass fiber; 8-15 parts brominated flame retardant; 2-5 parts solid flame retardant synergist; 0.2-1 part liquid flame retardant synergist; 0.1-1 part lubricant; 0-5 parts toughening agent; and 1-3 parts other processing aids. This PBT-based composite material possesses low fiber float, low exudation, enhanced flame retardancy, and excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and in particular to a PBT-based composite material and its preparation method. Background Technology

[0002] Polybutylene terephthalate (PBT) has excellent toughness and fatigue resistance, and can be used to manufacture various parts for aerospace, automotive and electrical electronics and other fields, realizing "replacing steel with plastics". With the upgrading and transformation of industrial technology, the use of engineering plastics and modified plastics will further increase.

[0003] In traditional technology, to achieve the goal of "replacing steel with plastic," PBT products need to be modified. In the process of modifying PBT, glass fiber, flame retardants, and some additives are usually added to improve the properties of PBT materials, such as reinforcement, flame retardancy, and toughening. However, during the injection molding process, problems often occur, such as severe fiber floating on the product surface, a lot of mold fouling during injection molding, and the precipitation of unknown substances on the surface of the product after it has been left for a period of time. This limits the performance of the modified material, and also results in an uneven surface and fiber floating on the injection molded sample, affecting its use. In addition, in continuous processing, the mold needs to be cleaned regularly, which increases production costs.

[0004] Therefore, it is necessary to optimize traditional production technologies and develop a PBT-based composite material with low fiber floating, low precipitation, low fouling, enhanced flame retardancy, and excellent mechanical properties. Summary of the Invention

[0005] Based on this, the present invention provides a PBT-based composite material with low fiber floating, low precipitation, low fouling, enhanced flame retardancy and excellent mechanical properties, and a method for preparing the same.

[0006] In one aspect, the present invention provides a PBT-based composite material, wherein the PBT-based composite material comprises the following components in parts by mass:

[0007]

[0008]

[0009] The aforementioned PBT-based composite material comprises specific components and proportions. By coordinating PBT resin with PET resin, the viscosity difference between the components and alkali-free glass fiber can be reduced. At the same time, flame retardants, lubricants, and other additives are added to enhance the flame retardant effect. A liquid flame retardant synergist is also added to enable the raw materials to bond together more stably and to encapsulate small molecules in the raw materials. The specific components work synergistically through a specific proportion, enabling the PBT-based composite material to improve tensile and impact resistance, achieve excellent flame retardancy and good flowability, while reducing the precipitation of floating fibers and small molecules, thereby reducing the probability of surface precipitation problems.

[0010] The above-mentioned PBT-based composite material achieves the UL-94 standard 0.8mm V0 flame retardant rating, tensile strength exceeding 140MPa, and notched impact strength reaching 7KJ / m. 2 The above-mentioned performance.

[0011] In some embodiments, the intrinsic viscosity of the PBT resin is 0.75 dL / g to 1.00 dL / g; and / or

[0012] The intrinsic viscosity of the PET resin is 0.60 dL / g to 0.75 dL / g.

[0013] It should be noted that the above "intrinsic viscosity" was obtained by testing in accordance with the method of GB / T 14190-2017.

[0014] In some embodiments, the diameter of the alkali-free glass fiber is 10 μm to 14 μm.

[0015] In some embodiments, the brominated flame retardant includes at least one of brominated epoxy resin, decabromodiphenyl ethane, and brominated polycarbonate; and / or

[0016] The solid flame retardant synergist includes an antimony-containing flame retardant; and / or

[0017] The liquid flame retardant synergist includes liquid epoxy resin, wherein the epoxy equivalent of the liquid epoxy resin is 160 g / eq to 180 g / eq.

[0018] Liquid epoxy resin can improve the compatibility of PBT resin with alkali-free glass fiber.

[0019] In some embodiments, the lubricant comprises at least one of aliphatic carboxylic acid esters, erucamide, polyethylene wax, and oxidized polyethylene wax; and / or

[0020] The toughening agent includes at least one of ethylene-acrylate copolymer, ethylene-vinyl acetate copolymer, and methyl methacrylate-butadiene-styrene copolymer.

[0021] In some embodiments, the other processing aids include at least one of antioxidants, anti-drop agents, and black masterbatch; the antioxidants include at least one of phosphite antioxidants and hindered phenolic antioxidants; the anti-drop agents include at least one of polytetrafluoroethylene and its derivatives; and the black masterbatch is a PET carrier black masterbatch.

[0022] One aspect of the present invention provides a method for preparing a PBT-based composite material, comprising the following steps:

[0023] The components of the PBT-based composite material are mixed and extruded to prepare the PBT-based composite material.

[0024] In some embodiments, the mixing extrusion step includes the following steps:

[0025] The components of the raw materials for the PBT-based composite material, excluding the alkali-free glass fiber, are mixed to obtain a first mixture;

[0026] The first mixture is fed into the main feeder of a twin-screw extruder, and the alkali-free glass fiber is fed into another separate feeder, and then extrusion is performed.

[0027] Feeding alkali-free glass fibers into a separate feeder can reduce the chance of damage to the alkali-free glass fibers caused by the twin screw.

[0028] In some embodiments, the temperatures of each section from the feed port to the die head of the twin-screw extruder are 90±10℃, 230±10℃, 230±10℃, 225±10℃, 220±10℃, 220±10℃, 220±10℃, 225±10℃, 230±10℃, and 240±10℃, respectively.

[0029] Further control of the extrusion temperature can reduce the probability of excessive decomposition of small molecules due to heat, resulting in surface precipitation.

[0030] In a third aspect, the present invention provides a PBT-based composite material, wherein the PBT-based composite material is prepared by the preparation method of the PBT-based composite material of the second aspect. Detailed Implementation

[0031] To facilitate understanding of the present invention, a more comprehensive description will be provided below. Preferred embodiments of the invention are given in specific examples. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0034] As used herein, the terms "and / or," "or / and," and "and / or" encompass any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR."

[0035] In this invention, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0036] Unless otherwise specified, the temperature parameters in this invention can be either constant temperature treatment or variations within a certain temperature range. It should be understood that the constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument. Fluctuations are permitted within ranges such as ±5℃, ±4℃, ±3℃, ±2℃, and ±1℃. In this invention, the terms "room temperature" or "normal temperature" generally refer to 4℃ to 35℃, for example, 20℃ ±5℃.

[0037] The mass or weight of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship of mass or weight between the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the mass or weight mentioned in the embodiments of this invention can be units known in the chemical industry, such as μg, mg, g, and kg.

[0038] As described in the background section, traditional techniques typically involve adding glass fiber, flame retardants, and other additives to improve the properties of PBT materials during the modification process. However, problems such as fiber floating on the product surface often occur during the injection molding process of traditional techniques.

[0039] The study found that the above problems are mainly due to the following aspects: (1) PBT and glass fiber have poor compatibility, which makes it impossible for them to bond together effectively; (2) The viscosity difference between PBT and glass fiber is very large, which leads to the tendency of them to separate during the flow process. When the separation effect is greater than the adhesive force, they will separate and the glass fiber will float to the outer layer and be exposed; (3) The existence of shear force will not only cause local viscosity differences, but also damage the interface layer on the surface of glass fiber. The smaller the melt viscosity, the more damaged the interface layer, and the smaller the adhesive force on the glass fiber. When the viscosity is low enough, the glass fiber will get rid of the binding of the PBT resin matrix and gradually accumulate to the surface and be exposed; (4) The mold temperature affects the glass fiber. Due to the low temperature of the mold surface, the lightweight and fast-cooling glass fiber is frozen instantly. If it cannot be fully surrounded by the melt in time, it will be exposed and form "floating fiber"; (5) The precipitation of substances on the product surface and the generation of mold fouling are caused by the high content of small molecules in the material itself or the poor thermal stability of the material, resulting in too much content of small molecules decomposed during the product extrusion or injection molding process.

[0040] Based on this, after a large number of creative experiments, the technical personnel of the present invention obtained the technical solution of this application, which provides a composite material with low fiber floating, low exudation, excellent mechanical properties, and enhanced flame retardancy.

[0041] One embodiment of the present invention provides a PBT-based composite material, which comprises the following components in parts by mass:

[0042]

[0043]

[0044] It can be understood that PBT resin is polybutylene terephthalate; PET resin is polyethylene terephthalate.

[0045] The aforementioned PBT-based composite material includes specific components and proportions. The PBT resin coordinates with the PET resin to reduce the viscosity difference between the components and alkali-free glass fiber. Flame retardants, lubricants, and other additives are added to enhance the flame retardant effect. A liquid flame retardant synergist is also added to enable the raw materials to bond together more stably and to encapsulate small molecules in the raw materials. The specific components work synergistically through a specific proportion, enabling the PBT-based composite material to achieve high mechanical properties, excellent flame retardancy, and good flowability, while reducing the precipitation of floating fibers and small molecules, thereby reducing the probability of surface precipitation problems.

[0046] In some embodiments, the mass fractions of the PBT resin include: 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, and each of these minimum and maximum values, or a range of any two values.

[0047] In some of these embodiments, the intrinsic viscosity of the PBT resin is 0.75 dL / g to 1.00 dL / g.

[0048] In some embodiments, the mass fractions of the PET resin include 5, 6, 7, 8, 9, 10 parts, and any value between such a minimum and maximum value, or a range of any two values.

[0049] In some of these embodiments, the intrinsic viscosity of the PET resin is 0.60 dL / g to 0.75 dL / g.

[0050] Adjusting the intrinsic viscosity of PBT resin and / or PET resin can further reduce the viscosity difference between the components and alkali-free glass fiber, thus reducing the probability of surface precipitation problems.

[0051] It should be noted that the above "intrinsic viscosity" was obtained by testing in accordance with the method of GB / T 14190-2017.

[0052] In some embodiments, the mass fractions of the alkali-free glass fiber include 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, and each of these minimum and maximum values, or a range of any two values.

[0053] In some embodiments, the diameter of the alkali-free glass fiber is 10 μm to 14 μm.

[0054] Alkali-free glass fiber is glass fiber treated with a coupling agent. Alkali-free glass fiber has high tensile strength and good electrical insulation. By adjusting the diameter and length of alkali-free glass fiber, while maintaining excellent reinforcement effect, the dispersibility can be improved, further enhancing the reinforcement effect and reducing the probability of fiber floating.

[0055] In some embodiments, the mass fractions of the brominated flame retardant include 8, 9, 10, 11, 12, 13, 14, 15 parts, as well as each value between such a minimum and maximum value, or a range of any two values.

[0056] In some embodiments, the mass fractions of the aforementioned solid flame retardant synergist include: 2 parts, 3 parts, 4 parts, 5 parts, and each value between such a minimum and maximum value, or a range of any two values.

[0057] In some embodiments, the mass fractions of the liquid flame retardant synergist include: 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, and each value between such a minimum and maximum value, or a range of any two values.

[0058] In some embodiments, the brominated flame retardant includes at least one of brominated epoxy resin, decabromodiphenyl ethane, and brominated polycarbonate.

[0059] In some embodiments, the solid flame retardant synergist includes an antimony-containing flame retardant; alternatively, the solid flame retardant synergist includes antimony powder.

[0060] In some embodiments, the liquid flame retardant synergist includes a liquid epoxy resin with an epoxy equivalent of 160 g / eq to 180 g / eq.

[0061] Brominated flame retardants have the characteristics of good thermal stability, high bromine content, and low precipitation. Furthermore, brominated flame retardants and antimony-containing flame retardants have a very good synergistic flame retardant effect, which can further reduce the probability of decomposition caused by heating during the addition process.

[0062] In some embodiments, the mass fractions of the lubricant include: 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, and each value between such a minimum and maximum value, or a range of any two values.

[0063] In some embodiments, the lubricant includes at least one of aliphatic carboxylic acid esters, erucamide, polyethylene wax, and oxidized polyethylene wax.

[0064] In some embodiments, the toughening agent is expressed in parts by mass of 0, 1, 2, 3, 4, 5, or any value between such a minimum and maximum value, or a range of any two values.

[0065] In some embodiments, the toughening agent includes at least one of ethylene-acrylate copolymer, ethylene-vinyl acetate copolymer, and methyl methacrylate-butadiene-styrene copolymer.

[0066] In some embodiments, the mass fractions of the other processing aids mentioned above include: 1 part, 2 parts, 3 parts, and each value between such a minimum and maximum value, or a range of any two values.

[0067] In some embodiments, other processing aids include at least one of antioxidants, anti-drop agents, and black masterbatch; optionally, antioxidants include at least one of phosphite antioxidants and hindered phenolic antioxidants; anti-drop agents include at least one of polytetrafluoroethylene and its derivatives, and black masterbatch is PET carrier black masterbatch.

[0068] Another embodiment of the present invention provides a method for preparing the above-mentioned PBT-based composite material, comprising the following step S10.

[0069] Step S10: Mix and extrude the raw materials of PBT-based composite material to prepare PBT-based composite material.

[0070] In some embodiments, the mixing extrusion step includes the following steps S11 to S12.

[0071] Step S11: Mix the components of the PBT-based composite material except for the alkali-free glass fiber to obtain the first mixture.

[0072] The specific steps include: drying PBT resin and PET resin at 120℃~140℃ for 2h~4h, then mixing them together with toughening agent through a high-speed mixer, then adding liquid flame retardant synergist and mixing again through a high-speed mixer, then adding brominated flame retardant, solid flame retardant synergist, lubricant and other processing aids into the high-speed mixer again and mixing to obtain the first mixture.

[0073] It should be noted that the above "components of PBT-based composite materials" can be understood as the raw materials of the corresponding components of PBT-based composite materials.

[0074] Step S12: The first mixture is fed into the main feeder of the twin-screw extruder, and the alkali-free glass fiber is fed into another separate feeder, and then the extrusion process is carried out.

[0075] Feeding alkali-free glass fibers into a separate feeder can reduce the chance of damage to the alkali-free glass fibers caused by the twin screw.

[0076] Understandably, during the extrusion process, the raw materials undergo melting and plasticizing, kneading and mixing, and then are extruded from the extruder.

[0077] In some embodiments, after the mixing and extrusion step, the extruded product is further subjected to steps such as cooling, air drying, pelletizing, and collecting.

[0078] In some embodiments, the temperatures of each section from the feed port of the twin-screw extruder to the die head are 90±10℃, 230±10℃, 230±10℃, 225±10℃, 220±10℃, 220±10℃, 220±10℃, 225±10℃, 230±10℃, and 240±10℃, respectively.

[0079] Further control of the extrusion temperature can reduce the probability of excessive decomposition of small molecules due to heat, resulting in surface precipitation.

[0080] In some embodiments, the extruder screw speed of the twin-screw extruder is 300 rpm to 400 rpm, and the feeding speed is 500 kg / h to 800 kg / h.

[0081] In some embodiments, the twin-screw extruder is a KraussMaffei Φ50 twin-screw extruder.

[0082] In another aspect, the present invention provides a PBT-based composite material prepared by the above-described method for preparing PBT-based composite materials.

[0083] The aforementioned PBT-based composite material features low fiber float, low exudation, enhanced flame retardancy, and excellent mechanical properties, and can reduce production costs, which is conducive to large-scale industrial application.

[0084] Some embodiments of the present invention also provide an electronic and electrical component material, which includes a PBT-based composite material prepared by the method of preparing a PBT-based composite material according to the first aspect or the method of preparing a PBT-based composite material according to the second aspect.

[0085] The present invention will now be described with reference to specific embodiments. However, the present invention is not limited to the embodiments described below. It should be understood that the appended claims summarize the scope of the present invention. Under the guidance of the inventive concept, those skilled in the art should realize that any changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0086] The following are specific examples.

[0087] The sources of the main raw materials used in each embodiment and comparative example are explained below:

[0088] PBT resin: PBT KH2083, China Kanghui New Materials, the intrinsic viscosity of the resin is 0.83 dL / g.

[0089] PET resin: PET FG-604, Yizheng Chemical, China. The intrinsic viscosity of the resin is 0.67 dL / g.

[0090] Brominated flame retardants: Brominated epoxy resin CR-225K, Boruida; Decabromodiphenyl ethane SAYTEX 8010, Albemarle, USA.

[0091] Solid synergistic flame retardant: antimony powder, 99.8% specification, Flash Star.

[0092] Toughening agent: Ethylene-butyl acrylate copolymer, brand name W5A, Coase Chemical Co., Ltd.

[0093] Liquid flame retardant synergist: Liquid epoxy resin, NPEF170, Nan Ya Electronic Technology Co., Ltd.

[0094] Lubricant: LOXIOL P 861 / 3.5 ester lubricant, Corning.

[0095] Alkali-free glass fiber: ECS13-4.5-534A (glass fiber diameter: 13μm, Jushi Group); ECS10-3.0-534A (glass fiber diameter: 10μm, Jushi Group).

[0096] Other processing aids: Antioxidants: Irganox 1010, Irgafos 168, BASF; Anti-drop agents: FS-257, Hannahno; Black masterbatch: MBB 1411, Cabot.

[0097] Example 1

[0098] (1) PBT resin and PET resin are dried at 120°C for 4 hours, and then mixed with toughening agent through a high-speed mixer. Liquid flame retardant synergist is added and mixed again through a high-speed mixer. Then, brominated flame retardant, solid flame retardant synergist, lubricant and other processing aids are added to the high-speed mixer and mixed to obtain the first mixture.

[0099] (2) The first mixture is fed into the main feeder of the twin-screw extruder, and the alkali-free glass fiber is fed into other separate feeders. Then, the extrusion process is carried out: the mixture undergoes melt plasticizing, kneading and mixing, extrusion, cooling, air drying, pelletizing and collection to obtain the PBT-based composite material. The twin-screw extruder used is a KraussMaffei Φ50 twin-screw extruder with a screw speed of 400 rpm and a feeding speed of 500 kg / hour. The temperatures of each section from the feed port to the die head of the twin-screw extruder are 90℃, 230℃, 230℃, 225℃, 220℃, 220℃, 220℃, 225℃, 230℃ and 240℃, respectively.

[0100] The types and quantities of raw materials are shown in Table 1.

[0101] Examples 2-6

[0102] Examples 2 to 6 are basically the same as Example 1, except that the raw material ratios are different from those in Example 1. Please see Table 1 for details.

[0103] The other steps and conditions are the same as in Example 1.

[0104] Table 1

[0105]

[0106] Note: " / " indicates that the raw material does not exist.

[0107] Comparative Examples 1-4

[0108] Comparative Examples 1-4 are basically the same as Example 1, except that the raw material ratios are different from those in Example 1. Please see Table 2 for details.

[0109] The other steps and conditions are the same as in Example 1.

[0110] Table 2

[0111]

[0112]

[0113] Performance testing: The PBT-based composite materials prepared in the above embodiments and comparative examples were subjected to the following performance tests:

[0114] (1) Fiber Float Verification and Rating: The PBT-based composite material was processed by injection molding using a Dongguan Fuqiangxin injection molding machine (model HN-125): material temperature 260~280℃, injection speed medium to high speed, mold temperature 100℃, and a 60×60×1.5mm sample was injection molded. The fiber float condition on the sample surface was observed, and the fiber float was visually graded.

[0115] Grade 1: No loose fibers, smooth sample surface, smooth to the touch when gently touched with a finger;

[0116] Level 2: Less floating fibers, smooth sample surface, slight resistance when gently touched with a finger;

[0117] Level 3: The surface of the sample is generally loose and has silver streaks. When you touch it lightly with your finger, you will feel a slight prickling sensation.

[0118] Level 4: Excessive precipitation, obvious floating fibers on the sample surface, and severe silver streaks.

[0119] (2) Precipitation Verification Rating - Referring to the above injection molding process, the prepared PBT-based composite material was injection molded into a 60×60×1.5mm sample. The sample was placed in an oven at 120℃ and dried for 48 hours. After being removed and cooled to room temperature, the surface precipitates were observed, and the precipitation was visually graded.

[0120] Level 1: No precipitation, no precipitates are visible on the sample surface, and no change is observed when wiping with black paper;

[0121] Level 2: Less precipitation, no precipitates visible on the sample surface, a small amount of precipitates appear on the black paper after wiping;

[0122] Level 3: Precipitation is moderate. A small amount of precipitate can be seen on the surface of the sample. When wiped with black paper, a large amount of precipitate remains on the black paper.

[0123] Level 4: Excessive precipitation, with many precipitates clearly visible on the sample surface.

[0124] (3) Mold fouling verification and rating - The PBT-based composite material was processed by injection molding using a Dongguan Fuqiangxin injection molding machine (model HN-125): material temperature 260℃~280℃, injection speed medium to high speed, mold temperature 100℃, continuous injection for 2 hours, mold fouling amount was visually observed, and mold fouling was visually graded:

[0125] Level 1: Very little mold residue. No mold residue is visible at the mold residue collection point. Wiping with black paper leaves no change on the black paper. No mold residue is found elsewhere on the mold.

[0126] Level 2: Minimal mold residue; no mold residue is visible at the mold residue collection point; a small amount of mold residue is visible on the black paper after wiping; no mold residue is found elsewhere on the mold.

[0127] Level 3: Mold buildup is moderate. Slight mold buildup can be seen at the mold buildup collection point. When wiped with black paper, a large amount of buildup remains on the black paper. There is no mold buildup in other parts of the mold.

[0128] Level 4: Excessive mold residue is observed at the mold residue collection point, and there is also obvious mold residue in other parts of the mold.

[0129] (4) Other performance tests: The PBT-based composite material was dried at 140℃ for 4 hours; test specimens were prepared by injection molding according to the corresponding standards. The tensile strength was tested according to ISO 527-2012 standard, the impact strength was tested according to ISO 180A notched standard, and the flame retardancy rating was tested according to the UL94-2016 flammability standard. The standard strip specimen dimensions were 125±5mm in length, 13.0±0.5mm in width, and 0.8±0.15mm in thickness. Each group of 10 test specimens was treated at 23±2℃ and 50±5% for 48 hours.

[0130] Please see Table 3 for specific test results.

[0131] Table 3

[0132]

[0133] Comparative analysis of the performance test results of each embodiment and comparative example in Table 3 shows that: Comparative Example 1 did not add any flame retardant or synergistic flame retardant. Although the resulting composite material had very low exudation and mold fouling levels, achieving a rating of Level 1, its flame retardancy rating did not meet the relevant requirements, and its mechanical properties were also low; Comparative Example 2, although it added bromine-based flame retardants and synergistic flame retardants, achieved a flame retardancy rating of Level V, but its exudation rating and mold fouling level significantly decreased, with more exudate reaching Level 3, and its fiber floating level also reaching Level 3; Comparative Example 3 added a small amount of... While a certain amount of PET resin can improve tensile and notched impact properties, it has limited effect on alleviating the problem of fiber floating. In Comparative Example 4, the problems of fiber floating, exudation, and mold fouling were not effectively improved. However, the PBT-based composite materials prepared using the technical methods of this application in Examples 1-6 possess high mechanical properties, excellent flame retardancy, and can reduce fiber floating and surface exudation, achieving an exudation rating and mold fouling level of 1. The flame retardancy reaches UL-94 standard V0 level, the tensile strength can reach over 140 MPa, and the notched impact strength reaches 7 KJ / m². 2 above.

[0134] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a PBT-based composite material, characterized in that, The PBT-based composite material comprises the following components in parts by weight: 40 to 55 parts of PBT resin; 5 to 7 parts of PET resin; 28 to 32 parts of alkali-free glass fiber; 8 to 15 parts of brominated flame retardant; 2 to 5 parts of solid flame retardant synergist; 0.2 to 1 part of liquid flame retardant synergist; Lubricant 0.1 to 1 part; Toughening agent 0 to 5 parts; Other processing aids: 1 to 3 parts; The intrinsic viscosity of the PET resin is 0.60 dL / g to 0.75 dL / g; the liquid flame retardant synergist includes liquid epoxy resin, and the epoxy equivalent of the liquid epoxy resin is 160 g / eq to 180 g / eq. The preparation method of the PBT-based composite material includes the following steps: The PBT-based composite material is prepared by mixing and extruding the components of the PBT-based composite material. The mixed extrusion step includes the following steps: The components of the raw materials for the PBT-based composite material, excluding the alkali-free glass fiber, are mixed to obtain a first mixture; The first mixture is fed into the main feeder of a twin-screw extruder, and the alkali-free glass fiber is fed into another separate feeder, and then extrusion is performed. The temperatures of each section from the feed port to the die head of the twin-screw extruder are 90±10℃, 230±10℃, 230±10℃, 225±10℃, 220±10℃, 220±10℃, 220±10℃, 225±10℃, 230±10℃, and 240±10℃, respectively.

2. The method for preparing the PBT-based composite material as described in claim 1, characterized in that, The intrinsic viscosity of the PBT resin is 0.75 dL / g to 1.00 dL / g.

3. The process for the preparation of PBT-based composites according to any one of claims 1-2, characterized in that, The diameter of the alkali-free glass fiber is 10μm to 14μm.

4. The process for the preparation of PBT-based composites according to any one of claims 1 to 2, characterized in that, The brominated flame retardant includes at least one of brominated epoxy resin, decabromodiphenyl ethane, and brominated polycarbonate; and / or the solid flame retardant synergist includes an antimony-containing flame retardant.

5. The process for the preparation of PBT-based composites according to any one of claims 1 to 2, characterized in that, The lubricant includes at least one of aliphatic carboxylic acid esters, erucamide, polyethylene wax, and oxidized polyethylene wax; and / or the toughening agent includes at least one of ethylene-acrylate copolymer, ethylene-vinyl acetate copolymer, and methyl methacrylate-butadiene-styrene copolymer.

6. The method of producing a PBT-based composite material according to any one of claims 1 to 2, wherein The other processing aids include at least one of antioxidants, anti-drop agents, and black masterbatch; the antioxidants include at least one of phosphite antioxidants and hindered phenolic antioxidants; the anti-drop agents include at least one of polytetrafluoroethylene and its derivatives; and the black masterbatch is PET carrier black masterbatch.

7. A PBT-based composite material, characterized in that, The PBT-based composite material is prepared by the method for preparing PBT-based composite materials according to any one of claims 1 to 6.

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