PBT flame-retardant composite material with high CTI value and preparation method thereof

Abstract

The invention belongs to the technical field of modified plastics, and particularly relates to a PBT (polybutylene terephthalate) flame-retardant composite material with a high CTI (comparative tracking index) value and a preparation method thereof. The PBT flame-retardant composite material with the high CTI value comprises the following components in parts by weight: 45-65 parts of PBT resin; 10 to 20 parts of brominated flame retardant; 3 to 15 parts of a flame retardant synergist; 3 to 20 parts of polyolefin; 1-3 parts of a CTI auxiliary agent; 0-1 part of a processing aid; and the CTI auxiliary agent is a polyphosphate. The invention further discloses a preparation method of the PBT flame-retardant composite material with the high CTI value. The preparation method comprises the following steps: weighing the raw materials in parts by weight according to claim 1; the preparation method comprises the following steps: putting the weighed raw materials into a high-speed mixer, mixing for 2-5 minutes, discharging, and extruding and granulating by using a double-screw extruder. The polyolefin and the CTI auxiliary agent are compounded, so that the CTI value of the composite material can reach 800V, and the composite material has good flame retardant property.

Description

Technical Field

[0001] The invention belongs to the technical field of modified plastics, and particularly relates to a PBT flame retardant composite material with a high CTI value and a preparation method thereof. Background Art

[0002] The bromine-antimony flame retardant system for polybutylene terephthalate (PBT) is a common flame retardant choice in practice, offering good flame retardancy and a high cost-effectiveness. However, the presence of bromine-antimony can reduce the composite's Comparative Tracking Index (CTI) performance. Therefore, CTI additives are often added to improve the CTI. However, these CTI additives have limited effectiveness and are relatively expensive.

[0003] Polyolefins are a type of polymer material with high production volume and wide application due to their abundant raw materials, low cost, ease of processing and molding, and excellent overall performance. Key varieties include polyethylene and ethylene-based copolymers such as ethylene-vinyl acetate copolymers and ethylene-acrylic acid or acrylic acid ester copolymers; polypropylene and some propylene copolymers; polybutene-1; poly-4-methylpentene-1; and cycloolefin polymers.

[0004] With the promotion of new energy high-voltage platforms, the requirements for CTI 800V are increasing. In the process of automotive electrification, CTI greater than 600V is the most common requirement. In order to increase the range of electric vehicles, the use of higher DC voltage is necessary. At this time, the CTI of the material is required to be no less than 800V. Therefore, it is of great significance to develop a PBT flame-retardant composite material with a CTI value of no less than 800V. Summary of the Invention

[0005] In order to overcome the problem that existing CTI additives have limited effect in improving CTI values ​​and are relatively expensive, the present invention aims to provide a PBT flame-retardant composite material with a CTI value of not less than 800V, which is specifically achieved through the following technical solutions: A high CTI value PBT flame retardant composite material, comprising the following components in parts by weight: 45~65 parts of PBT resin 10-20 parts of brominated flame retardant; 3-15 parts of flame retardant synergist; 3-20 parts of polyolefin; 1~3 parts of CTI additive; Processing aid 0~1 part; The CTI additive is a polyphosphate.

[0006] Optionally, the viscosity of the PBT is 0.8-1.3 dl / g.

[0007] Optionally, the brominated flame retardant is one or more of brominated epoxy resin, brominated polystyrene, tetrabromobisphenol A, octabromoether and brominated triazine.

[0008] Optionally, the polyolefin is one or more of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, polyethylene, polypropylene, polybutene, cycloolefin copolymer, and metallocene polyolefin copolymer.

[0009] Optionally, the processing aid is one or more of an antioxidant, a lubricant, and an anti-dripping agent.

[0010] The present application also provides a method for preparing a high CTI value PBT flame retardant composite material, comprising the following steps: Weigh each raw material according to the weight parts described in claim 1; Put the weighed raw materials into a high-speed mixer, mix for 2 to 5 minutes, discharge the materials, and then extrude and granulate them using a twin-screw extruder.

[0011] Optionally, the processing temperature of the twin-screw extruder is 250-270° C., and the screw speed is 30-40 Hz.

[0012] Compared with the prior art, the present invention has the following beneficial effects: in the PBT flame retardant composite material, by compounding polyolefin with a CTI additive, the CTI value of the composite material can reach 800V and has good flame retardant properties. DETAILED DESCRIPTION

[0013] The specific implementation methods of the present application are described in detail below through examples, but the specific implementation of this application does not serve as a limitation on the technical solution of the present application. Any non-substantial changes such as replacement of common technical solutions in the field using the technical solutions described in the examples of this application are within the scope of protection of this application. It should be noted that the addition of processing aids is a conventional technical means in this field, so that the material obtains or helps to obtain other beneficial properties, such as toughening agents, impact modifiers, antistatic agents, ultraviolet absorbers, colorants, antioxidants, release agents, heat stabilizers, light stabilizers, nucleating agents, ester exchange inhibitors, interfacial modifiers and chain extenders. As conventional technical means, those skilled in the art should understand that they can freely choose within a reasonable range according to specific needs, and will not limit the scope of protection of the present invention.

[0014] 1. The sources of raw materials used in the present invention are as follows: PBT resin: commercially available brand KH2080, purchased from Kanghui New Material Technology Co., Ltd. Glass fiber: commercially available brand ECS10-03-534H, purchased from China Jushi Co., Ltd. Brominated flame retardant: commercially available brand EP-25K, purchased from Jiangsu Xingsheng Chemical Co., Ltd. Flame retardant synergist: commercially available brand TS-9080, purchased from Shanghai Muli Antimony Industry Sales Co., Ltd. Ethylene-vinyl acetate copolymer (EVA): commercially available brand ELVAX 265, purchased from DuPont; Ethylene ethyl acrylate copolymer (EEA): commercially available brand AC-2615, purchased from DuPont; Ethylene-butyl acrylate copolymer (EBA): commercially available brand AC-3427, purchased from DuPont; CTI additive A (polyphosphate): commercially available brand CZ-A90G30, purchased from PolyQian; CTI additive B (TPP): commercially available brand BUDIT T31, purchased from Budenheim; (hypophosphite) Antioxidant: Commercially available brand 1010, purchased from Lionlong.

[0015] 2. Product performance test standards are as follows: (1) CTI value: Tested according to IEC60112 standard.

[0016] (2) Flame retardant performance: tested using the UL94-2013 combustion standard.

[0017] 3. Product preparation method: Weigh the raw material components according to the weight ratio and premix them in a high-speed mixer to obtain a premix; The premix is ​​fed into a twin-screw extruder from a main feed port, and glass fiber is fed from a side feed port. After melt blending, extrusion, cooling, air drying, and granulation, a PBT flame retardant composite material is obtained.

[0018] The examples and comparative examples are shown in Tables 1-2. Table 1: Content of each component and test results of PBT flame retardant composite materials in Examples 1 to 5, each component is in parts by weight Example 1 Example 2 Example 3 Example 4 Example 5 PBT resin 65 45 65 65 65 Brominated flame retardants 15 15 15 15 15 Flame retardant synergist 5 5 5 5 5 EVA 8 3 3 EEA 8 EBA 8 CTI Additive A 3 1 3 3 1 CTI Additive B antioxidants 0.2 0.2 0.2 0.2 0.2 Flame retardant properties V0 V0 V0 V0 V0 CTI (V) 800 800 800 800 800 Table 2: Content of each component and test results of PBT flame retardant composite materials in comparative examples 1 to 5, each component is in parts by weight Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 PBT resin 65 65 65 65 65 Brominated flame retardants 15 15 15 15 15 Flame retardant synergist 5 5 5 5 5 EVA 8 8 CTI Additive A 3 CTI Additive B 3 3 antioxidants 0.2 0.2 0.2 0.2 0.2 Flame retardant properties V0 V0 V0 V0 V0 CTI (V) 250 600 300 300 625 It can be seen from the examples and comparative examples in Table 1 and Table 2 above that in the PBT bromine antimony flame retardant system: When polyolefin and CTI additives are not added to the system, the CTI of the material is extremely low, only 250V. When polyolefin and polyphosphate CTI additives are added, the CTI value can reach 800V. When only polyolefin is added to the system, the CTI value of the material is improved to 600V, but it still cannot reach 800V. Similarly, when only CTI additives are added to the system, the CTI value of the material can be improved, but the increase in the CTI value is still small. When polyolefin and non-polyphosphate CTI additives are added to the system, the CTI value of the material is 625V, which still cannot reach 800V. When polyolefin and polyphosphate CTI additives are added to the system, the CTI value of the material can reach 800V, which shows that polyolefin and polyphosphate CTI additives have a synergistic effect on improving the CTI value of PBT bromine antimony flame retardant system.

Claims

1. A high CTI value PBT flame retardant composite material, characterized in that: Calculated by weight, it includes the following components: 45-65 parts of PBT resin; 10-20 parts of brominated flame retardant; 3-15 parts of flame retardant synergist; 3-20 parts of polyolefin; 1~3 parts of CTI additive; Processing aid 0~1 part; The CTI additive is a polyphosphate.

2. The high CTI value PBT flame retardant composite material according to claim 1, characterized in that: The viscosity of the PBT is 0.8-1.3 dl / g.

3. The high CTI value PBT flame retardant composite material according to claim 1, characterized in that: The brominated flame retardant is one or more of brominated epoxy resin, brominated polystyrene, tetrabromobisphenol A, octabromoether and brominated triazine.

4. The high CTI value PBT flame retardant composite material according to claim 1, characterized in that: The polyolefin is one or more of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, polyethylene, polypropylene, polybutene, cycloolefin copolymer, and metallocene polyolefin copolymer.

5. The high CTI value PBT flame retardant composite material according to claim 1, characterized in that: The processing aid is one or more of an antioxidant, a lubricant, and an anti-dripping agent.

6. A method for preparing a high CTI value PBT flame retardant composite material, characterized in that: The steps include: Weigh each raw material according to the weight parts described in claim 1; Put the weighed raw materials into a high-speed mixer, mix for 2 to 5 minutes, discharge the materials, and then extrude and granulate them using a twin-screw extruder.

7. The preparation method according to claim 6, characterized in that The processing temperature of the twin-screw extruder is 250-270° C., and the screw speed is 30-40 Hz.