A high-toughness flame-retardant PA66 composite material for connectors and its preparation method

Abstract

This invention discloses a high-toughness flame-retardant PA66 composite material for connectors and its preparation method. The preparation method includes the following steps: mixing a first elastomer, a second elastomer, maleic anhydride powder, an initiator, and an antioxidant uniformly to obtain a first composition; mixing BPS powder, silicone resin, stearate, and a flame-retardant synergist uniformly to obtain a second composition; feeding the first composition into a Banbury mixer for internal mixing, then feeding the second composition into the Banbury mixer in portions for continued internal mixing; finally, feeding the obtained Banbury product into a screw extruder for extrusion and granulation to obtain BPS / silicone flame retardant masterbatch; mixing PA66, BPS / silicone flame retardant masterbatch, lubricant, and antioxidant uniformly, then feeding the mixture into a twin-screw extruder for extrusion and granulation to obtain the high-toughness flame-retardant PA66 composite material. This invention improves the flame-retardant properties of PA66 composite materials and effectively reduces the amount of BPS added in the flame-retardant system.

Description

Technical Field

[0001] This invention relates to PA66 composite materials, and particularly to a high-toughness flame-retardant PA66 composite material for connectors and its preparation method. Background Technology

[0002] Connectors, also known as plugs, are mainly used for connecting circuits. They are essential core components for electrical connections in circuit systems and are widely used in smart homes, automobiles, communications, computers and peripherals, industry, military and aerospace, and other fields. Currently, the main material used for connectors is bromine-based flame-retardant PA66 material containing decabromodiphenyl ethane (DBDPE). DBDPE has poor stability and certain toxicity, and there is a risk that it will be banned in the future. Therefore, there is an urgent need for a new alternative material for bromine-based flame-retardant PA66 material used in connectors.

[0003] Chinese patent CN116102881B discloses a brominated flame-retardant polyamide composite material, its preparation method, and its application. The material comprises: 36-52 parts aliphatic polyamide; 6-18 parts aromatic polyamide; 15-50 parts glass fiber; and 17-30 parts a bromine / antimony flame retardant. The bromine / antimony flame retardant is a compound of brominated polystyrene (BPS) and antimony trioxide. However, this method has drawbacks such as high BPS content, insufficient toughness of the composite material, and poor resistance to electrical tracking. Summary of the Invention

[0004] To overcome the aforementioned shortcomings and deficiencies of the prior art, the present invention aims to provide a method for preparing a high-toughness flame-retardant PA66 composite material for connectors. This method involves compounding BPS and an organosilicon flame retardant into a composite masterbatch (with an elastomer graft as the matrix) and then introducing it into the PA66 matrix. This improves the dispersion effect of the flame retardant, enabling a good synergistic effect among the BPS flame retardant, organosilicon flame retardant, flame retardant synergist, and resin matrix. This, in turn, enhances the flame-retardant properties of the PA66 composite material and effectively reduces the amount of BPS added to the flame-retardant system.

[0005] Another object of the present invention is to provide a high-toughness flame-retardant PA66 composite material for inserts.

[0006] Another object of the present invention is to provide a method for preparing BPS / organosilicon flame retardant.

[0007] Another object of the present invention is to provide a BPS / organosilicon flame retardant.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] This invention provides a method for preparing a high-toughness flame-retardant PA66 composite material for connectors, comprising the following steps:

[0010] (1) Preparation of BPS / organosilicon flame retardant masterbatch:

[0011] By weight, 35-62 parts of a first elastomer, 35-64 parts of a second elastomer, 0.5-2.5 parts of maleic anhydride powder, 0.1-0.3 parts of an initiator, and 0.2-0.4 parts of an antioxidant are mixed evenly to obtain a first composition; the first elastomer is a styrene-based block copolymer; the second elastomer is an ethylene-octene copolymer or ethylene propylene diene monomer (EPDM) rubber;

[0012] The second composition is obtained by uniformly mixing 40-70 parts of BPS powder, 20-39 parts of silicone resin, 0.5-1 part of stearate, and 9-20.5 parts of flame retardant synergist.

[0013] Add 10-30 parts of the first composition into a mixer and mix at 150-200℃ for 5-15 minutes. Then add 70-90 parts of the second composition into the mixer in 3-5 portions. After all the second composition has been added, continue mixing for 2-5 minutes. Finally, send the resulting mixed product into a single-screw or twin-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0014] (2) Preparation of high-toughness flame-retardant PA66 composite materials:

[0015] By weight, 59-74 parts of PA66, 25-40 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.2-0.8 parts of lubricant and 0.2-0.8 parts of antioxidant are added to a mixer for initial mixing and uniform mixing. The initial mixture is then fed into a twin-screw extruder for extrusion and granulation to obtain a high-toughness flame-retardant PA66 composite material.

[0016] Preferably, the styrene-based block copolymer is at least one of styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-ethylene-propylene-styrene block copolymer (SEPS).

[0017] Preferably, the initiator in step (1) is one of dicumyl peroxide (DCP), 2,5-dimethyl-2,5-bis-tert-butylperoxide (DBPH), benzoyl peroxide (BPO), and bis-tert-butylperoxide (BIPB).

[0018] Preferably, the antioxidant in step (1) is at least one of the following: antioxidant BHT, antioxidant 1010, antioxidant 1098, antioxidant 245, antioxidant 1076, antioxidant AO-20, antioxidant 3391, antioxidant 445, antioxidant H3336, antioxidant HSO2, antioxidant 168, and antioxidant PEPQ.

[0019] Preferably, the organosilicon resin in step (1) is one of methyl silicone resin, ethyl silicone resin, vinyl phenyl silicone resin, isopropyl silicone resin, phenyl silicone resin, methyl phenyl silicone resin, vinyl phenyl silicone resin, and phosphorus-containing methyl phenyl silicone resin.

[0020] Preferably, the stearate in step (1) is at least one of calcium stearate, zinc stearate, magnesium stearate, barium stearate, sodium stearate and lithium stearate; the flame retardant synergist in step (1) is at least one of zinc borate, antimony trioxide, antimony pentoxide and sodium antimonate.

[0021] Preferably, the lubricant in step (2) is at least one of OP wax, E wax, rice bran wax, silicone powder, ethylene bis-stearamide and pentaerythritol stearate; the antioxidant in step (2) is at least one of antioxidant BHT, antioxidant 1010, antioxidant 1098, antioxidant 245, antioxidant 1076, antioxidant AO-20, antioxidant 3391, antioxidant 445, antioxidant H3336, antioxidant HSO2, antioxidant 168 and antioxidant PEPQ.

[0022] The present invention also provides a high-toughness flame-retardant PA66 composite material for connectors, which is prepared by the preparation method of the high-toughness flame-retardant PA66 composite material for connectors.

[0023] This invention also provides a method for preparing a BPS / organosilicon flame retardant, comprising the following steps:

[0024] By weight, 35-62 parts of a first elastomer, 35-64 parts of a second elastomer, 0.5-2.5 parts of maleic anhydride powder, 0.1-0.3 parts of an initiator, and 0.2-0.4 parts of an antioxidant are mixed evenly to obtain a first composition; the first elastomer is a styrene-based block copolymer; the second elastomer is an ethylene-octene copolymer or ethylene propylene diene monomer (EPDM) rubber;

[0025] The second composition is obtained by uniformly mixing 40-70 parts of BPS powder, 20-39 parts of silicone resin, 0.5-1 part of stearate, and 9-20.5 parts of flame retardant synergist.

[0026] Add 10-30 parts of the first composition into a mixer and mix at 150-200℃ for 5-15 minutes. Then add 70-90 parts of the second composition into the mixer in 3-5 batches. After all the second composition has been added, continue mixing for 2-5 minutes. Finally, send the resulting mixed product into a single-screw or twin-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0027] The present invention also provides a BPS / organosilicon flame retardant, which is prepared by the preparation method of the BPS / organosilicon flame retardant.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] (1) The preparation method of the high-toughness flame-retardant PA66 composite material for connectors of the present invention involves compounding BPS and silicone resin into a masterbatch and introducing it into the PA66 matrix, which can effectively improve the dispersion of BPS. This is because after the styrene-based block copolymer matrix is ​​modified by maleic anhydride grafting, BPS is coated during the preparation of the masterbatch, and then it can act as a bridge between BPS and PA66 during the blending process, significantly improving the dispersion of BPS. This can reduce the amount of flame retardant added to a certain extent while maintaining good flame retardant effect.

[0030] (2) The method for preparing high-toughness flame-retardant PA66 composite material for connectors of the present invention involves grafting and modifying POE or EPDM with styrene-based block copolymers, and then introducing it into the PA66 composite material system as the matrix of flame-retardant masterbatch. This method can effectively reduce the crystallinity of PA66 and significantly improve the toughness of the composite material.

[0031] (3) The preparation method of the high toughness flame retardant PA66 composite material for connectors of the present invention, in the preparation of BPS / organosilicon flame retardant masterbatch, by introducing stearate, can enable the metal ions carried by it to undergo coordination complexation reaction with the matrix graft to form ionomers, and further form ion clusters in the material, resulting in ion crosslinking. When subjected to external impact, the stress inside the material is dispersed by the formed crosslinking network, and the impact strength is enhanced, which can further effectively improve the rheological properties and impact properties of the flame retardant PA66 composite material system.

[0032] (4) The preparation method of the high toughness flame retardant PA66 composite material for connectors of the present invention, in the preparation of BPS / organosilicon flame retardant masterbatch, the organosilicon resin and flame retardant synergists such as zinc borate, antimony trioxide, antimony pentoxide, and sodium antimonate work together to have anti-dripping effect and effectively reduce the amount of BPS used, further reducing costs and reducing the gas with strong odor generated by the decomposition of BPS flame retardant during production and processing. At the same time, it can improve the tracking index (CTI) of the composite material, which can simultaneously meet the requirements of low bromine content and high CTI for bromine-based flame retardant PA66.

[0033] (5) The high-toughness flame-retardant PA66 composite material for connectors of the present invention has the characteristics of high fluidity, easy processing, low temperature resistance and excellent impact resistance, and has high application value in various connectors. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0035] Example 1

[0036] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 49 parts of SEBS, 49 parts of POE, 1.5 parts of maleic anhydride powder, 0.2 parts of DCP initiator, and 0.3 parts of antioxidant (antioxidant 1010 and 168 in a 2:1 ratio) were added to a mixer and mixed evenly to obtain composition 1. Then, 60 parts of BPS powder, 23 parts of phosphorus-containing methylphenyl silicone resin, 0.6 parts of zinc stearate, and 16.4 parts of antimony trioxide were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 20 parts of composition 1 were added to a mixer and mixed at 185°C for 8 minutes. Then, 80 parts of composition 2 were added to the mixer in 4 portions. After all the contents were added, the mixer was continued for 3 minutes. Finally, the resulting product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0037] (2) Preparation of high-toughness flame-retardant PA66 composite material. 64 parts of PA66, 35 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.5 parts of rice bran wax and 0.5 parts of antioxidant (1098 and PEPQ in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0038] Example 2

[0039] (1) Preparation of BPS / silicone flame retardant masterbatch. First, 35 parts of SEBS, 64 parts of POE, 0.5 parts of maleic anhydride powder, 0.1 parts of DBPH initiator and 0.4 parts of antioxidant 1098 were added to a mixer and mixed evenly to obtain composition 1. Then, 60 parts of BPS powder, 23 parts of methyl silicone resin, 0.6 parts of aluminum stearate and 16.4 parts of zinc borate were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 20 parts of composition 1 were added to a mixer and mixed at 150°C for 15 minutes. Then, 80 parts of composition 2 were added to the mixer in 3 portions. After all the contents were added, the mixer was continued for 5 minutes. Finally, the obtained mixer product was fed into a twin-screw extruder for extrusion and granulation to obtain BPS / silicone flame retardant masterbatch.

[0040] (2) Preparation of high-toughness flame-retardant PA66 composite material. 64 parts of PA66, 35 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.5 parts of OP wax and 0.5 parts of antioxidant (1098 and 168 in a ratio of 3:2) were put into a mixer for initial mixing and uniform mixing. The initial mixture was then fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0041] Example 3

[0042] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 62 parts of SEBS, 35 parts of POE, 2.5 parts of maleic anhydride powder, 0.3 parts of BPO initiator and 0.2 parts of antioxidant 1076 were added to a mixer and mixed evenly to obtain composition 1. Then, 60 parts of BPS powder, 23 parts of methylphenyl silicone resin, 0.6 parts of calcium stearate and 16.4 parts of sodium antimonate were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 20 parts of composition 1 were added to a mixer and mixed at 200°C for 5 minutes. Then, 80 parts of composition 2 were added to the mixer in 5 portions. After all the contents were added, the mixer was continued for 2 minutes. Finally, the obtained mixer product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0043] (2) Preparation of high-toughness flame-retardant PA66 composite material. 64 parts of PA66, 35 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.5 parts of ethylene bis-stearamide and 0.5 parts of antioxidant (1010 and 168 in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0044] Example 4

[0045] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 49 parts of SEBS, 49 parts of POE, 1.5 parts of maleic anhydride powder, 0.2 parts of DCP initiator, and 0.3 parts of antioxidant (antioxidant 1010 and 168 in a 2:1 ratio) were added to a mixer and mixed evenly to obtain composition 1. Then, 70 parts of BPS powder, 20 parts of phosphorus-containing methylphenyl silicone resin, 1 part of zinc stearate, and 9 parts of antimony trioxide were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 20 parts of composition 1 were added to a mixer and mixed at 185°C for 8 minutes. Then, 80 parts of composition 2 were added to the mixer in 4 portions. After all the portions were added, the mixer was continued for 3 minutes. Finally, the resulting product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0046] (2) Preparation of high-toughness flame-retardant PA66 composite material. 64 parts of PA66, 35 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.5 parts of rice bran wax and 0.5 parts of antioxidant (1098 and PEPQ in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0047] Example 5

[0048] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 49 parts of SEBS, 49 parts of POE, 1.5 parts of maleic anhydride powder, 0.2 parts of DCP initiator, and 0.3 parts of antioxidant (antioxidant 1010 and 168 in a 2:1 ratio) were added to a mixer and mixed evenly to obtain composition 1. Then, 40 parts of BPS powder, 39 parts of phosphorus-containing methylphenyl silicone resin, 0.5 parts of zinc stearate, and 20.5 parts of antimony trioxide were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 20 parts of composition 1 were added to a mixer and mixed at 185°C for 8 minutes. Then, 80 parts of composition 2 were added to the mixer in 4 portions. After all the contents were added, the mixer was continued for 3 minutes. Finally, the obtained mixer product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0049] (2) Preparation of high-toughness flame-retardant PA66 composite material. 64 parts of PA66, 35 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.5 parts of rice bran wax and 0.5 parts of antioxidant (1098 and PEPQ in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0050] Example 6

[0051] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 49 parts of SEBS, 49 parts of POE, 1.5 parts of maleic anhydride powder, 0.2 parts of DCP initiator, and 0.3 parts of antioxidant (antioxidant 1010 and 168 in a 2:1 ratio) were added to a mixer and mixed evenly to obtain composition 1. Then, 60 parts of BPS powder, 23 parts of phosphorus-containing methylphenyl silicone resin, 0.6 parts of zinc stearate, and 16.4 parts of antimony trioxide were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 10 parts of composition 1 were added to a mixer and mixed at 185°C for 8 minutes. Then, 90 parts of composition 2 were added to the mixer in 4 portions. After all the contents were added, the mixer was continued for 3 minutes. Finally, the obtained mixer product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0052] (2) Preparation of high-toughness flame-retardant PA66 composite material. 64 parts of PA66, 35 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.5 parts of rice bran wax and 0.5 parts of antioxidant (1098 and PEPQ in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0053] Example 7

[0054] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 49 parts of SEBS, 49 parts of POE, 1.5 parts of maleic anhydride powder, 0.2 parts of DCP initiator, and 0.3 parts of antioxidant (antioxidant 1010 and 168 in a 2:1 ratio) were added to a mixer and mixed evenly to obtain composition 1. Then, 60 parts of BPS powder, 23 parts of phosphorus-containing methylphenyl silicone resin, 0.6 parts of zinc stearate, and 16.4 parts of antimony trioxide were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 30 parts of composition 1 were added to a mixer and mixed at 185°C for 8 minutes. Then, 70 parts of composition 2 were added to the mixer in 4 portions. After all the contents were added, the mixer was continued for 3 minutes. Finally, the resulting product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0055] (2) Preparation of high-toughness flame-retardant PA66 composite material. 64 parts of PA66, 35 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.5 parts of rice bran wax and 0.5 parts of antioxidant (1098 and PEPQ in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0056] Example 8

[0057] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 49 parts of SEBS, 49 parts of POE, 1.5 parts of maleic anhydride powder, 0.2 parts of DCP initiator, and 0.3 parts of antioxidant (antioxidant 1010 and 168 in a 2:1 ratio) were added to a mixer and mixed evenly to obtain composition 1. Then, 60 parts of BPS powder, 23 parts of phosphorus-containing methylphenyl silicone resin, 0.6 parts of zinc stearate, and 16.4 parts of antimony trioxide were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 20 parts of composition 1 were added to a mixer and mixed at 185°C for 8 minutes. Then, 80 parts of composition 2 were added to the mixer in 4 portions. After all the contents were added, the mixer was continued for 3 minutes. Finally, the resulting product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0058] (2) Preparation of high-toughness flame-retardant PA66 composite material. 74 parts of PA66, 25 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.8 parts of rice bran wax and 0.2 parts of antioxidant (1098 and PEPQ in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0059] Example 9

[0060] (1) Preparation of BPS / organosilicon flame retardant masterbatch. First, 49 parts of SEBS, 49 parts of POE, 1.5 parts of maleic anhydride powder, 0.2 parts of DCP initiator, and 0.3 parts of antioxidant (antioxidant 1010 and 168 in a 2:1 ratio) were added to a mixer and mixed evenly to obtain composition 1. Then, 60 parts of BPS powder, 23 parts of phosphorus-containing methylphenyl silicone resin, 0.6 parts of zinc stearate, and 16.4 parts of antimony trioxide were added to a mixer and mixed evenly to obtain composition 2. After the initial mixing, 20 parts of composition 1 were added to a mixer and mixed at 185°C for 8 minutes. Then, 80 parts of composition 2 were added to the mixer in 4 portions. After all the contents were added, the mixer was continued for 3 minutes. Finally, the resulting product was fed into a single-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch.

[0061] (2) Preparation of high-toughness flame-retardant PA66 composite material. 59 parts of PA66, 40 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.2 parts of rice bran wax and 0.8 parts of antioxidant (1098 and PEPQ in a ratio of 3:2) were put into a mixer and mixed evenly. Then the mixture was fed into a twin-screw extruder for extrusion and granulation to obtain high-toughness flame-retardant PA66 composite material.

[0062] Comparative Example 1

[0063] Compared to Example 1, 49 SEBS and 49 POE were replaced with 98 POE.

[0064] Comparative Example 2

[0065] Compared to Example 1, no stearate is added to Composition 2.

[0066] Comparative Example 3

[0067] Compared to Example 1, no silicone resin is added to Composition 2.

[0068] Comparative Example 4

[0069] The materials and additives used in Example 1, such as PA66, SEBS, POE, and BPS, were all added to a mixer in the corresponding proportions of Example 1 and mixed evenly. The mixture was then fed into a twin-screw extruder for extrusion and granulation to obtain a flame-retardant PA66 composite material.

[0070] Comparative Example 5

[0071] Except for SEBS, POE elastomer and maleic anhydride powder, all other materials and additives used in Example 1 were added to a mixer in the corresponding proportions of Example 1 and mixed evenly. The mixture was then fed into a twin-screw extruder for extrusion and granulation to obtain flame-retardant PA66 composite material.

[0072] Material testing methods

[0073] Flame retardant performance: tested according to UL94 test standard;

[0074] CTI: Tested according to IEC60112 testing standard;

[0075] Impact performance: The notched impact strength of a simply supported beam was tested according to standard ISO 179-1.

[0076] All test specimens were prepared by injection molding machine and tested after being conditioned for 28 hours in a standard environment of 50±5% relative humidity and 23±2℃. The test results are shown in Table 1.

[0077] Table 1. Performance test results of flame-retardant PA66 composite materials prepared in the examples and comparative examples.

[0078] Test items Flame retardant properties CTI / V <![CDATA[Notch impact strength / kJ·m -2 > Example 1 0.8mm V-0 350 12.5 Example 2 1.6mm V-0 350 12.7 Example 3 0.8mm V-0 350 12.0 Example 4 0.8mm V-0 325 11.0 Example 5 1.6mm V-0 350 11.2 Example 6 0.8mm V-0 350 9.2 Example 7 1.6mm V-0 325 15.2 Example 8 3.2mm V-0 300 9.7 Example 9 0.8mm V-0 350 13.3 Comparative Example 1 1.6mm V-0 325 11.4 Comparative Example 2 0.8mm V-0 350 12.1 Comparative Example 3 1.6mm V-0 250 12.6 Comparative Example 4 3.2mm V-1 325 8.9 Comparative Example 5 3.2mm V-1 325 4.9

[0079] Table 1 shows the performance test results of the flame-retardant PA66 composite materials prepared in each embodiment and comparative example. A comparison of the test results of Examples 1-9 and Comparative Examples 1-5 in the table shows that the flame-retardant PA66 composite material prepared in this invention possesses excellent flame-retardant properties, impact resistance, and resistance to tracking. It can fully meet the requirements for replacing DBDPE flame-retardant PA66 composite materials, low bromine content, and high CTI performance, and has high application value in various connectors.

[0080] A comparison of Examples 1-3 and Comparative Example 1 shows that elastomer 1 performs better in improving the dispersion of BPS, while elastomer 2 performs better in improving the toughness (impact resistance; higher impact strength results in better toughness) of the composite system. However, the overall performance decreases significantly when only one elastomer is added. A comparison of Example 1 and Comparative Example 2 shows that the introduction of stearate can improve the impact performance of the composite system to a certain extent. A comparison of Examples 1, 4-5, and Comparative Example 3 shows that the introduction of organosilicon can significantly reduce the amount of BPS added and effectively improve the CTI performance of the composite system. A comparison of Example 1... Comparisons 6-7 show that, at the same addition amount, the higher the content of flame retardant in the BPS / organosilicon flame retardant masterbatch, the better the flame retardant effect and CTI effect, but the lower the toughness. However, when the CTI increases to a certain value, it no longer increases with the increase of content. Comparisons 1 and 8-9 show that with the increase of the addition amount of BPS / organosilicon flame retardant masterbatch, the flame retardant performance, impact performance, and resistance to tracking are also significantly improved. Comparisons 1 and 4-5 show that by combining the flame retardant and elastomer through the masterbatch method and then introducing them into the PA66 composite material system, the present invention has obvious comprehensive performance advantages.

[0081] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-toughness flame-retardant PA66 composite material for connectors, characterized in that, Includes the following steps: (1) Preparation of brominated polystyrene (BPS) / organosilicon flame retardant masterbatch: By weight, 35-62 parts of a first elastomer, 35-64 parts of a second elastomer, 0.5-2.5 parts of maleic anhydride powder, 0.1-0.3 parts of an initiator, and 0.2-0.4 parts of an antioxidant are mixed evenly to obtain a first composition; the first elastomer is a styrene-based block copolymer; the second elastomer is an ethylene-octene copolymer; The second composition is obtained by uniformly mixing 40-70 parts of BPS powder, 20-39 parts of silicone resin, 0.5-1 part of stearate, and 9-20.5 parts of flame retardant synergist. Add 10-30 parts of the first composition into a mixer and mix at 150-200℃ for 5-15 minutes. Then add 70-90 parts of the second composition into the mixer in 3-5 portions. After all the second composition has been added, continue mixing for 2-5 minutes. Finally, send the resulting mixed product into a single-screw or twin-screw extruder for extrusion and granulation to obtain BPS / organosilicon flame retardant masterbatch. (2) Preparation of high-toughness flame-retardant PA66 composite material: By weight, 59-74 parts of PA66, 25-40 parts of BPS / organosilicon flame retardant masterbatch prepared in step (1), 0.2-0.8 parts of lubricant and 0.2-0.8 parts of antioxidant are added to a mixer for initial mixing and uniform mixing. The initial mixture is then fed into a twin-screw extruder for extrusion and granulation to obtain a high-toughness flame-retardant PA66 composite material.

2. The method for preparing high-toughness flame-retardant PA66 composite material for connectors according to claim 1, characterized in that, The styrene-based block copolymer is at least one of styrene-butadiene-styrene block copolymer, styrene-ethylene-butene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and styrene-ethylene-propylene-styrene block copolymer.

3. The method for preparing high-toughness flame-retardant PA66 composite material for connectors according to claim 1, characterized in that, The initiator in step (1) is one of dicumyl peroxide, 2,5-dimethyl-2,5-ditert-butylperoxide, benzoyl peroxide, and ditert-butylperoxide.

4. The method for preparing high-toughness flame-retardant PA66 composite material for connectors according to claim 1, characterized in that, The antioxidant mentioned in step (1) is at least one of the following: antioxidant BHT, antioxidant 1010, antioxidant 1098, antioxidant 245, antioxidant 1076, antioxidant AO-20, antioxidant 3391, antioxidant 445, antioxidant H3336, antioxidant HSO2, antioxidant 168, and antioxidant PEPQ.

5. The method for preparing high-toughness flame-retardant PA66 composite material for connectors according to claim 1, characterized in that, The organosilicon resin mentioned in step (1) is one of methyl silicone resin, ethyl silicone resin, vinyl phenyl silicone resin, isopropyl silicone resin, phenyl silicone resin, methyl phenyl silicone resin, vinyl phenyl silicone resin, and phosphorus-containing methyl phenyl silicone resin.

6. The method for preparing high-toughness flame-retardant PA66 composite material for connectors according to claim 1, characterized in that, The stearate in step (1) is at least one of calcium stearate, zinc stearate, magnesium stearate, barium stearate, sodium stearate and lithium stearate; the flame retardant synergist in step (1) is at least one of zinc borate, antimony trioxide, antimony pentoxide and sodium antimonate.

7. The method for preparing high-toughness flame-retardant PA66 composite material for connectors according to claim 1, characterized in that, The lubricant in step (2) is at least one of OP wax, rice bran wax, silicone powder, ethylene bis-stearamide and pentaerythritol stearate; the antioxidant in step (2) is at least one of antioxidant BHT, antioxidant 1010, antioxidant 1098, antioxidant 245, antioxidant 1076, antioxidant AO-20, antioxidant 3391, antioxidant 445, antioxidant H3336, antioxidant HSO2, antioxidant 168 and antioxidant PEPQ.

8. A high-toughness flame-retardant PA66 composite material for connectors, characterized in that, It is prepared by the method for preparing high-toughness flame-retardant PA66 composite material for connectors as described in any one of claims 1 to 7.