Flame-retardant PBT / ABS composite material as well as preparation method and application thereof

Abstract

The invention discloses a flame-retardant PBT / ABS (polybutylene terephthalate / acrylonitrile-butadiene-styrene) composite material which comprises the following components in parts by weight: the sum of parts by weight of PBT and ABS is 100 parts; 10 to 25 parts of a compound flame retardant; 2-8 parts of a flame retardant synergist; 5 to 40 parts of glass fiber; wherein the weight ratio of PBT to ABS is (10-2): 1; the compound flame retardant is selected from compounding of brominated epoxy and other polymer brominated flame retardants, the brominated epoxy accounts for 5-50% of the total weight of the compound flame retardant, and the other polymer brominated flame retardants are selected from at least one of brominated polystyrene, polybrominated styrene, polypentabromobenzyl methacrylate and brominated polycarbonate. The flame-retardant PBT / ABS composite material which is low in warpage, stable in reproducibility and capable of being subjected to repeated cyclic injection molding processing can be obtained by adjusting the ratio of PBT to ABS and compounding the brominated macromolecular flame retardant.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a flame retardant PBT / ABS composite material and a preparation method and application thereof. Background Art

[0002] Polybutylene terephthalate (PBT) is widely used in the fields of electronics, household appliances, and automotive parts due to its excellent comprehensive properties, strong chemical stability, mechanical strength, electrical insulation, thermal stability, low water absorption, high fluidity, and strong crystallization performance. However, due to its own structural and performance characteristics, PBT has disadvantages such as large molding shrinkage, poor dimensional stability, and low notched impact strength, which limits its application in many fields. At the same time, glass fiber is usually required for modification in the application of PBT to enhance the mechanical properties, but the orientation of glass fiber leads to a small shrinkage rate in the process direction of glass fiber reinforced materials during injection molding, and a large shrinkage rate in the direction perpendicular to the process. The shrinkage rate of the injection molded parts is anisotropic, which eventually leads to warping. Combined with the crystallinity of PBT itself, the anisotropy of glass fiber reinforced PBT materials during the injection molding stage causes serious warping problems.

[0003] In order to solve the above problems, some low-crystalline or amorphous materials are usually added to PBT, such as PC and ABS, which can improve flatness and low 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 filler makes the material have ultra-low warpage performance. However, due to the existence of ester exchange, it is difficult to maintain good mechanical properties after multiple cycles of injection molding, so it cannot meet the needs of adding and reusing nozzle materials in actual production. At the same time, in the process of polyester material application injection molding, conventional molds will produce injection nozzle materials with no use value after injection molding parts. Usually, the nozzle materials are crushed and mixed with new materials for secondary injection molding. If the performance of the material deteriorates severely at high temperature and carbonized black spots appear on the appearance, it cannot meet the needs of multiple cycles of injection molding and is difficult to reuse, resulting in waste of resources. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical defects and provide a flame retardant PBT / ABS composite material with good dimensional stability, stable regeneration and multiple injection molding cycles.

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

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

[0007] The difference between brominated polystyrene and polybrominated styrene is that the two have different synthesis methods. Brominated polystyrene is obtained by brominating polystyrene; while polybrominated styrene is obtained by first protecting the olefinic bonds of styrene and then brominating it, restoring the olefinic bonds of the brominated monomer to obtain brominated styrene, and then polymerizing it.

[0008] Brominated polycarbonate is a flame retardant that is partially brominated with polycarbonate, and its bromine content is greater than 58%.

[0009] In the technical solution of the present 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 the present invention.

[0010] The present invention has no particular limitation on the parameters of the glass fiber, which may be continuous glass fiber or chopped glass fiber, and the diameter may range from 9 to 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] The present invention has no special requirements for PBT and ABS. When the intrinsic viscosity of PBT is between 0.8-1.2dL / g, the test standard is based on ASTM D-2857; when the melt flow rate of ABS is between 1-40g / 10min, the test standard is ASTM D-1238 (test temperature 200°C, load 5kg), both can achieve the purpose of the present invention.

[0014] ABS is an acrylonitrile-butadiene-styrene terpolymer, wherein the present invention has no limitation on the contents of the three monomers, and the acrylonitrile content ranges from 10-30wt%, the butadiene content ranges from 10-30wt%, and the styrene content ranges from 30-70wt%.

[0015] Preferably, the brominated epoxy accounts for 15-40% of the total weight of the composite 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] The present invention has no particular limitation on the parameters of the flame retardant synergist. When the average particle size of the flame retardant synergist is in the range of 0.5-0.9 μm, good flame retardancy can be achieved. The average particle size is tested by a particle size analyzer.

[0020] It is possible to choose whether to add 0-2 parts of an auxiliary agent according to actual needs, wherein the auxiliary agent is selected from at least one of an antioxidant, a lubricant, and a weathering agent.

[0021] The preparation method of the flame retardant PBT / ABS composite material comprises the following steps: adding each component into a twin-screw extruder according to a proportion, extruding and granulating, and obtaining the flame retardant PBT / ABS composite material.

[0022] The flame retardant PBT / ABS composite materials are used to prepare components of electronic appliances, especially electronic connectors.

[0023] The present invention has the following beneficial effects The present invention can effectively improve the warpage defect through a specific ratio of PBT / ABS. At the same time, the polymer brominated flame retardant contains a specific proportion of brominated epoxy, which can produce cross-linking during the long-term use of the composite material, thereby improving the long-term heat aging resistance; at the same time, the compounding of brominated epoxy and other polymer brominated flame retardants can not only give play to the cross-linking characteristics of brominated epoxy itself, but also limit the specific content of brominated epoxy to avoid the carbonization problem caused by excessive content of brominated epoxy in multiple cycles, inhibit the generation of black spots in the composite material during multiple injection molding, and improve the repeated injection molding performance. DETAILED DESCRIPTION

[0024] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0025] The sources of raw materials used in the present invention are as follows: PBT-A: PBT 1200-211M, Changchun, Taiwan, China; PBT-B: PBT GX121, Yizheng Chemical Fiber, China; ABS-A: ABS PA757, Chimei, Taiwan, China; ABS-B: ABS DG MG29, Dagu, Tianjin, China; Brominated epoxy: F-2100, CL, Israel; Brominated polystyrene: SAYTEX 621, Albemarle, USA; Polybrominated styrene: PBS-64HW, Chemtura, USA; Polypentabromobenzyl methacrylate: FR-1025, CL, Israel; Brominated polycarbonate: FG8500, Teijin; Antimony trioxide: S-05N, Chenzhou Antimony Industry; Glass fiber: ECS10-4.5-T436H, Taishan Glass Fiber Co., Ltd. Antioxidant: Antioxidant 1010, commercially available.

[0026] Embodiment and comparative example Preparation method of flame-retardant PBT / ABS composite material: Mix all components evenly, add into twin-screw extruder, mix, disperse, melt extrude, granulate, the temperature section setting of twin-screw extruder is divided into 10 sections, namely, the temperature of zone 1 is 220-240°C, the temperature of zone 2 is 230-245°C, the temperature of zone 3 is 235-245°C, the temperature of zone 4 is 235-250°C, the temperature of zone 5 is 220-240°C, the temperature of zone 6 is 220-240°C, the temperature of zone 7 is 210-230°C, the temperature of zone 8 is 200-220°C, the temperature of zone 9 is 200-220°C, and the temperature of zone 10 is 220-240°C. The aspect ratio is 32-40:1, and the screw speed is 250-400 rpm.

[0027] Various test methods: (1) Warpage: Injection molding a square plate with a size of 100 mm × 100 mm × 1 mm. Place the square plate on a horizontal marble table top. Fix one corner of the square plate against the marble table top. Measure the distance between the diagonal position of the square plate and the marble table top. 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 was crushed into particles with a diameter of no more than 5 mm, and the sample was re-injected. The above process was repeated 3 times, and the tensile performance retention rate was tested.

[0029] Table 1: Weight parts of each component and test results of flame retardant PBT / ABS composite materials of Examples 1-8 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 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 Epoxy Bromide 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 It can be seen from Examples 1 / 4-8 that the tensile property retention rate is higher when the weight ratio of PBT to ABS is preferred, and at the same time, the tensile strength is greater than 100 MPa.

[0030] Table 2: Weight parts of each component and test results of flame retardant PBT / ABS composite materials of Examples 9-16 Example 9 Example 10 Embodiment 11 Example 12 Example 13 Embodiment 14 Embodiment 15 Example 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 Epoxy Bromide 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 Polypentabromobenzyl 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 It can be seen from Examples 1 / 9-11 that other high molecular weight brominated flame retardants preferably have the best repeated injection molding performance when polypentabromobenzyl methacrylate and brominated polycarbonate are used.

[0031] It can be seen from Examples 1 / 12-16 that when the epoxy bromide accounts for 15-40% of the total weight of the compound flame retardant, the repeated injection molding performance is improved and the warping is reduced. It is more preferred that when the epoxy bromide accounts for 20-30% of the total weight of the compound flame retardant, almost no warping can be achieved and the repeated injection molding performance is the best.

[0032] Table 3: Weight parts of each component and test results of comparative flame retardant PBT / ABS composite materials Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 PBT-A 50 92.3 87.5 87.5 ABS-A 50 7.7 100 12.5 12.5 Epoxy Bromide 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 It can be seen from Comparative Examples 1-3 that when the weight ratio of PBT to ABS is not within the scope of this application, the technical effects of low warpage and best repeated injection molding performance cannot be achieved at the same time.

[0033] It can be seen from Comparative Examples 4-5 that if the ratio of the compound flame retardant is not within the scope of the present application, the technical effects of low warpage and best repeated injection molding performance cannot be achieved 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 weight of PBT and ABS is 100 parts; 10-25 parts of compound flame retardant; 2-8 parts of flame retardant synergist; Glass fiber 5-40 parts; Among them, the weight ratio of PBT to ABS is (10-2):1; The compound flame retardant is selected from the compound of brominated epoxy and other polymer brominated flame retardants, wherein brominated epoxy accounts for 5-50% of the total weight of the compound flame retardant, and the other polymer brominated flame retardant is selected from at least one of brominated polystyrene, polybrominated styrene, polypentabromobenzyl methacrylate, and brominated polycarbonate.

2. The flame retardant PBT / ABS composite material according to claim 1, characterized in that: The weight ratio of PBT to ABS is (8-3):

1.

3. The flame retardant PBT / ABS composite material according to claim 2, characterized in that: The weight ratio of PBT to ABS is (7-4.5):

1.

4. 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.

5. The flame retardant PBT / ABS composite material according to claim 4, characterized in that: Brominated epoxy accounts for 20-30% of the total weight of the compound flame retardant.

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

7. 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.

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

9. The method for preparing the flame retardant PBT / ABS composite material according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: adding each component into a twin-screw extruder according to a proportion, extruding and granulating, and obtaining a flame-retardant PBT / ABS composite material.

10. Use of the flame retardant PBT / ABS composite material according to any one of claims 1 to 8, characterized in that: Used to prepare components for electronic appliances.