Flame-retardant pbt / abs composite material, preparation method and application thereof

Abstract

The application discloses a kind of flame-retardant PBT / ABS composite material, by weight parts, including the following components: the sum of PBT and ABS is 100 parts by weight;Compound flame retardant is 10-25 parts;Flame retardant synergist is 2-8 parts;Glass fiber is 5-40 parts;Wherein, the weight ratio of PBT and ABS is (10-2):1;The compound flame retardant is selected from the compound of brominated epoxy and other high molecular bromine flame retardant, wherein brominated epoxy accounts for 5-50% of the total weight parts of compound flame retardant, the other high molecular bromine flame retardant is selected from at least one of brominated polystyrene, polybrominated styrene, poly (pentabromobenzyl methacrylate), brominated polycarbonate.The application can obtain a kind of low warping, can be recycled stable, can be recycled injection molding processing flame-retardant PBT / ABS composite material by adjusting the ratio of PBT and ABS, compound bromine polymer flame retardant.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a flame-retardant PBT / ABS composite material, its preparation method, and its application. Background Technology

[0002] Polybutylene terephthalate (PBT) is widely used in electronics, home appliances, and automotive parts due to its excellent comprehensive properties, including strong chemical stability, mechanical strength, electrical insulation, thermal stability, low water absorption, high flowability, and strong crystallinity. However, due to its inherent structural and performance characteristics, PBT suffers from drawbacks such as high molding shrinkage, poor dimensional stability, and low notched impact strength, which limits its application in many fields. Furthermore, PBT applications often require modification with glass fiber to enhance its mechanical properties. However, the orientation of glass fiber results in a smaller shrinkage rate in the flow direction and a larger shrinkage rate perpendicular to the flow direction during injection molding, leading to anisotropy in the shrinkage rate of the injection-molded part and ultimately causing warping. Combined with the inherent crystallinity of PBT and the anisotropy of glass fiber reinforced PBT materials during injection molding, this results in severe warping problems.

[0003] To address the aforementioned issues, low-crystallinity or amorphous materials are typically added to PBT. For example, adding PC or ABS can improve smoothness and reduce warpage. Patent CN109337302A discloses an ultra-low warpage glass fiber reinforced PBT / PC / ABS ternary alloy material. The synergistic effect of amorphous resin and mineral fillers gives the material ultra-low warpage performance. However, due to transesterification, it is difficult to maintain good mechanical properties after multiple injection molding cycles, thus failing to meet the practical production requirements for reusing sprue material. Furthermore, during the injection molding process of polyester materials, conventional molds produce unusable sprue material after injection molding. This sprue material is usually crushed and mixed with virgin material for secondary injection molding. If the material's performance deteriorates severely at high temperatures and carbonized black spots appear on the surface, it cannot meet the requirements for multiple injection molding cycles, making reuse difficult and resulting in resource waste. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical defects and provide a flame-retardant PBT / ABS composite material with good dimensional stability, recyclability, and the ability to be repeatedly injection molded.

[0005] This invention is achieved through the following technical solution: A flame-retardant PBT / ABS composite material, comprising the following components by weight: The sum of the weights of PBT and ABS is 100 parts; 10-25 parts of compound flame retardant; 2-8 parts of flame retardant synergist; 5-40 parts glass fiber; The weight ratio of PBT to ABS is (10-2):1; The compound flame retardant is selected from a compound of brominated epoxy and other high molecular weight brominated flame retardants, wherein the brominated epoxy accounts for 5-50% of the total weight of the compound flame retardant, and the other high molecular weight brominated flame retardants are selected from at least one of brominated polystyrene, polybrominated polystyrene, polypentabromobenzyl methacrylate, and brominated polycarbonate.

[0006] The CAS number for polypentabromobenzyl methacrylate is 61803-56-3.

[0007] The difference between brominated polystyrene and polybrominated polystyrene lies in their synthesis methods. Brominated polystyrene is obtained by brominating polystyrene, while polybrominated polystyrene is obtained by first protecting the olefin bonds of styrene and then brominating it, restoring the olefin bonds of the brominated monomer to obtain styrene brominated polystyrene, and then polymerizing it.

[0008] Brominated polycarbonate is a flame retardant that partially bromines polycarbonate, and its bromine content is >58%.

[0009] In the technical solution of this invention, the total weight of PBT and ABS accounts for more than 55% of the total weight of the flame-retardant PBT / ABS composite material of this invention.

[0010] This invention does not impose any particular limitations on the parameters of the glass fiber; it can be continuous glass fiber or chopped glass fiber, and the diameter range can be 9-15 μm.

[0011] Preferably, the weight ratio of PBT to ABS is (8-3):1.

[0012] More preferably, the weight ratio of PBT to ABS is (7-4.5):1.

[0013] This invention does not have special requirements for PBT and ABS. When the intrinsic viscosity of PBT is between 0.8-1.2 dL / g, the test standard is ASTM D-2857; when the melt flow rate of ABS is between 1-40 g / 10 min, the test standard is ASTM D-1238 (test temperature 200℃, load 5 kg), which can achieve the purpose of this invention.

[0014] ABS is an acrylonitrile-butadiene-styrene terpolymer. In this invention, there is no limitation on the content of the three monomers. The acrylonitrile content ranges from 10-30 wt%, the butadiene content ranges from 10-30 wt%, and the styrene content ranges from 30-70 wt%.

[0015] Preferably, the brominated epoxy accounts for 15-40% of the total weight of the compounded flame retardant.

[0016] More preferably, the brominated epoxy accounts for 20-30% of the total weight of the compounded flame retardant.

[0017] Preferably, the other high molecular weight brominated flame retardant is selected from at least one of polypentabromobenzyl methacrylate and brominated polycarbonate.

[0018] The flame retardant synergist is selected from at least one of antimony trioxide and sodium antimonate.

[0019] This invention does not impose any particular limitations on the parameters of the flame retardant synergist. Good flame retardancy can be achieved when the average particle size of the flame retardant synergist is in the range of 0.5-0.9 μm. The average particle size is measured by a particle size analyzer.

[0020] Depending on actual needs, 0-2 parts of additives may be added, wherein the additives are selected from at least one of antioxidants, lubricants, and weather-resistant agents.

[0021] The preparation method of flame-retardant PBT / ABS composite material includes the following steps: according to the formula, each component is added to a twin-screw extruder, extruded and granulated to obtain flame-retardant PBT / ABS composite material.

[0022] Flame-retardant PBT / ABS composite materials are used to manufacture electronic and electrical components, especially electronic connectors.

[0023] The present invention has the following beneficial effects This invention effectively improves warpage defects through a specific ratio of PBT / ABS. Simultaneously, the high-molecular-weight brominated flame retardant contains a specific proportion of brominated epoxy, which can crosslink the composite material during long-term use, thereby improving its long-term heat aging resistance. Furthermore, the combination of brominated epoxy with other high-molecular-weight brominated flame retardants not only leverages the crosslinking properties of brominated epoxy itself, but also, by limiting the specific content of brominated epoxy, avoids carbonization problems caused by excessive content during repeated processing, inhibits the formation of black spots in the composite material during multiple injection molding processes, and improves re-injection molding performance. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. 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. These all fall within the scope of protection of the present invention.

[0025] The raw materials used in this invention are sourced from the following sources: PBT-A: PBT 1200-211M, Changchun, Taiwan, China; PBT-B: PBT GX121, Yizheng Chemical Fiber, China; ABS-A: ABS PA757, manufactured by Chi Mei Pharmaceutical Co., Ltd. in Taiwan, China. ABS-B: ABS DG MG29, Dagu, Tianjin, China; Brominated epoxy: F-2100, Israel CL; Brominated polystyrene: SAYTEX 621, Albemarle, USA; Polybrominated styrene: PBS-64HW, from Kelpie Chemicals, USA; Poly(pentabromobenzyl methacrylate): FR-1025, Israel CL; Brominated polycarbonate: FG8500, Teijin; Antimony trioxide: S-05N, Chenzhou Antimony Industry; Fiberglass: ECS10-4.5-T436H, Taishan Fiberglass Co., Ltd.; Antioxidant: Antioxidant 1010, commercially available.

[0026] Preparation method of flame-retardant PBT / ABS composite material in the examples and comparative examples: All components were mixed uniformly and fed into a twin-screw extruder. The mixture was then subjected to mixing, dispersion, melt extrusion, and granulation. The twin-screw extruder was configured with 10 temperature zones: Zone 1 (220-240℃), Zone 2 (230-245℃), Zone 3 (235-245℃), Zone 4 (235-250℃), Zone 5 (220-240℃), Zone 6 (220-240℃), Zone 7 (210-230℃), Zone 8 (200-220℃), Zone 9 (200-220℃), and Zone 10 (220-240℃). The length-to-diameter ratio was 32-40:1, and the screw speed was 250-400 rpm.

[0027] Test methods: (1) Warpage: The injection molded square plate is 100mm×100mm×1mm. Place the square plate on a horizontal marble tabletop, fix one corner of the square plate to be close to the marble tabletop, measure the distance between the diagonal position of the square plate and the marble tabletop, and take the maximum value among the test results of the four corners of the square plate as its warpage result.

[0028] (2) Repeated injection molding performance: The injection molded sample is broken into particles with a diameter of no more than 5 mm, and the sample is re-injected. The above process is repeated 3 times, and the tensile property retention rate is tested.

[0029] Table 1: Weight parts of each component and test results of flame-retardant PBT / ABS composite materials in Examples 1-8 PBT-A 87.5 87.5 90.9 88.9 83.3 75 66.7 PBT-B 87.5 ABS-A 12.5 12.5 9.1 11.1 16.7 25 33.3 ABS-B 12.5 Brominated epoxy 4 6 2.5 4 4 4 4 4 Brominated polystyrene 12 18 7.5 12 12 12 12 12 Antimony trioxide 3 2 8 3 3 3 3 3 Fiberglass 20 20 40 20 20 20 20 20 antioxidants 0.3 0.6 Warpage, mm 0 0 0.5 0.2 0.1 0 0 0 Tensile strength, MPa 110 112 132 108 110 106 103 88 Tensile property retention rate, % 90 91 90 86 87 91 88 81 As can be seen from Examples 1 / 4-8, the tensile properties are better maintained when the weight ratio of PBT to ABS is optimized, and the tensile strength is >100MPa.

[0030] Table 2: Weight parts and test results of each component in flame-retardant PBT / ABS composite materials of Examples 9-16 PBT-A 87.5 87.5 87.5 87.5 87.5 87.5 87.5 87.5 ABS-A 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 Brominated epoxy 4 4 4 0.8 2.4 4.8 6.4 8 Brominated polystyrene 15.2 13.6 11.2 9.6 8 Polybrominated styrene 12 Poly(pentabromobenzyl methacrylate) 12 Brominated polycarbonate 12 Antimony trioxide 3 3 3 3 3 3 3 3 Fiberglass 20 20 20 20 20 20 20 20 Warpage, mm 0.1 0 0 0.1 0 0 0 0 Tensile strength, MPa 110 115 108 104 106 108 106 105 Tensile property retention rate, % 89 95 93 82 85 88 83 80 As can be seen from Examples 1 / 9-11, other high molecular weight brominated flame retardants, preferably polypentabromobenzyl methacrylate and brominated polycarbonate, exhibit the best repeated injection molding performance.

[0031] As can be seen from Examples 1 / 12-16, when the brominated epoxy accounts for 15-40% of the total weight of the compound flame retardant, the repeat injection molding performance is improved and the warpage is reduced. More preferably, when the brominated epoxy accounts for 20-30% of the total weight of the compound flame retardant, almost no warpage can be achieved, and the repeat injection molding performance is the best.

[0032] Table 3: Weight parts and test results of each component in comparative flame-retardant PBT / ABS composite materials PBT-A 50 92.3 87.5 87.5 ABS-A 50 7.7 100 12.5 12.5 Brominated epoxy 4 4 4 0 16 Brominated polystyrene 12 12 12 16 0 Antimony trioxide 3 3 3 3 3 Fiberglass 20 20 20 20 20 Warpage, mm 0 3 0 0.9 0 Tensile strength, MPa 86 105 78 98 105 Tensile property retention rate, % 58 77 44 65 53 As can be seen from Comparative Examples 1-3, when the weight ratio of PBT to ABS is not within the range of this application, it is impossible to simultaneously achieve the technical effects of low warpage and the best repeat injection molding performance.

[0033] As can be seen from Comparative Examples 4-5, if the ratio of the compound flame retardant is not within the range of this application, it is also impossible to achieve the technical effect of low warpage and best repeat injection molding performance at the same time.

Claims

1. A flame-retardant PBT / ABS composite material, characterized in that, By weight, it includes the following components: The sum of the weights of PBT and ABS is 100 parts; 10-25 parts of compound flame retardant; 2-8 parts of flame retardant synergist; 5-40 parts glass fiber; The weight ratio of PBT to ABS is (7-5):1; The compound flame retardant is selected from a compound of brominated epoxy and other high molecular weight brominated flame retardants, wherein the brominated epoxy accounts for 5-50% of the total weight of the compound flame retardant, and the other high molecular weight brominated flame retardants are selected from at least one of brominated polystyrene, polybrominated polystyrene, polypentabromobenzyl methacrylate, and brominated polycarbonate.

2. The flame-retardant PBT / ABS composite material according to claim 1, characterized in that, Brominated epoxy accounts for 15-40% of the total weight of the compound flame retardant.

3. The flame-retardant PBT / ABS composite material according to claim 2, characterized in that, Brominated epoxy accounts for 20-30% of the total weight of the compound flame retardant.

4. The flame-retardant PBT / ABS composite material according to claim 1, characterized in that, The other high molecular weight brominated flame retardants are selected from at least one of polypentabromobenzyl methacrylate and brominated polycarbonate.

5. The flame-retardant PBT / ABS composite material according to claim 1, characterized in that, The flame retardant synergist is selected from at least one of antimony trioxide and sodium antimonate.

6. The flame-retardant PBT / ABS composite material according to claim 1, characterized in that, The product also includes 0-2 parts by weight of additives, wherein the additives are selected from at least one of antioxidants, lubricants, and weathering agents.

7. The method for preparing the flame-retardant PBT / ABS composite material according to any one of claims 1-6, characterized in that, The process includes the following steps: according to the formula, each component is added to a twin-screw extruder, extruded and granulated to obtain a flame-retardant PBT / ABS composite material.

8. The application of the flame-retardant PBT / ABS composite material according to any one of claims 1-6, characterized in that, Used to manufacture electronic and electrical components.