Halogen-free flame-retardant reinforced PPE / PA6 composition with high CTI value and preparation method thereof

Abstract

The invention discloses a halogen-free flame-retardant reinforced PPE / PA6 composition with a high CTI (comparative tracking index) value and a preparation method of the halogen-free flame-retardant reinforced PPE / PA6 composition. The halogen-free flame-retardant reinforced PPE / PA6 composition comprises the following raw materials in percentage by mass: 7%-30% of high-fluidity PPE, 20%-40% of high-fluidity PA6, 3%-10% of a toughening agent, 4%-8% of a halogen-free flame retardant, 3%-7% of a compatilizer, 20%-50% of glass fibers, 2%-5% of a CTI (comparative tracking index) enhancing aid, 1.3%-1.7% of linear low-density polyethylene and 1%-5% of other aids. The halogen-free flame-retardant reinforced PPE / PA6 alloy material provided by the invention has an excellent CTI (Comparative Tracking Index) value (700V) and good flame retardance (1.6 mm-V0), and can be applied to new energy automobile battery components, electronic appliances and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering plastic alloy materials, and specifically relates to a high CTI value halogen-free flame retardant reinforced PPE / PA6 composition and a preparation method thereof. Background Art

[0002] With the technological innovation and lightweight demand, the trend of engineering plastics replacing metal materials in the automotive field is accelerating. As a high-performance engineering plastic, polyphenylene ether (PPE) has many advantages such as low density, low water absorption, intrinsic flame retardancy and good dimensional stability, but it has a large melt viscosity, is not easy to process and has poor resistance to organic solvents. The product is prone to stress cracking due to residual stress. Polyamide (PA) has excellent mechanical properties, good resistance to organic solvents and oil, but has high water absorption, poor dimensional stability and poor heat deformation resistance under high load. PPE / PA alloy has the advantages of both, with excellent mechanical properties, high heat deformation temperature, good dimensional stability and excellent processing performance. It can be widely used in low-voltage electronic capacitor housings, load break switches, molded case circuit breakers and other electronic and electrical products.

[0003] However, due to the high carbonization of PPE resin, flashover discharge will be formed at a voltage of about 300V, and then carbides will be generated on the surface to form a conductive path, which ultimately makes the CTI performance of conventional PPE / PA materials poor. In addition, since the synthesis of PA66 resin is affected by the shortage of raw material adiponitrile, its price has remained high, resulting in a high price for PPE / PA66 alloy products. Based on the above problems, it is urgent to develop a PPE / PA6 material that takes into account low cost, high flame retardancy, excellent mechanical properties and high CTI value, in order to meet the stringent requirements of electronic appliances, especially long-term unattended appliances. Summary of the invention

[0004] The object of the present invention is to overcome the defects and shortcomings in the prior art and provide a high CTI value halogen-free flame retardant reinforced PPE / PA6 composition, which is composed of the following raw materials in percentage by mass: high-flowability PPE 7-30%, high-flowability PA6 20-40%, toughening agent 3-10%, halogen-free flame retardant 4-8%, compatibilizer 3-7%, glass fiber 20-50%, CTI improving additive 2-5%, linear low-density polyethylene 1.3-1.7%, and other additives 1-5%.

[0005] The high-fluidity PPE resin has an intrinsic viscosity of 0.33-0.37 dl / g, a melt flow rate (315°C, 10kg) of 45-65 g / 10min, and a notched impact strength of ≥3 kJ / m 2 ;

[0006] The high-fluidity PA6 resin has a relative viscosity of 2.0, a melt flow rate (230°C, 2.16kg) of 100-120g / 10min, and a notched impact strength of ≥5kJ / m 2 .

[0007] The toughening agent is at least one of a SEBS elastomer and a maleic anhydride grafted POE elastomer; the preferred SEBS elastomer is a linear transparent SEBS, whose styrene content is 29.5-32.5% by mass percentage and whose toluene viscosity (10% / 25°C) is 300-500cp; the preferred maleic anhydride grafted POE elastomer has a functional group content of 0.4%-0.8% by mass percentage and a melt flow rate (190°C, 2.16kg) of 0.5-2.5g / 10min.

[0008] The compatibilizer is maleic anhydride grafted PPE, and its density is 1.06g / cm 3 The maleic anhydride grafting rate is 0.7-0.9% by mass.

[0009] The halogen-free flame retardant is a microcapsule-coated red phosphorus flame retardant with PA6 resin as the carrier and a density of 1.40-1.60 g / cm 3 , phosphorus content is 40-45%, and the ignition point is ≥320℃.

[0010] The CTI improving agent is hydroxyapatite, which has a volume density of 22 g / l, a CaO content of 55% by mass, a P2O5 content of 41% by mass, a pH value of 7, and a particle size (d50) of 3.1 μm.

[0011] The glass fiber is an alkali-free glass fiber, and its average diameter is 1-20 μm, and its average length is 1-10 mm. Preferably, the average diameter of the glass fiber is 8-12 μm, and its average length is 2-4 mm.

[0012] The linear low-density polyethylene has a melt flow rate (190°C, 2.16kg) of 18-22g / 10min and a notched impact strength of ≥53kJ / m 2 .

[0013] The other auxiliary agents include aniline black material, which uses PA6 resin as a carrier and has an aniline black content of 40%.

[0014] The preparation method of the above-mentioned high CTI value halogen-free flame retardant reinforced PPE / PA6 composition comprises the following steps: weighing high-flowability PPE resin, high-flowability PA6 resin, compatibilizer, toughening agent, halogen-free flame retardant, CTI improving additive, linear low-density polyethylene and other additives are mixed evenly in a high-speed mixer to obtain a mixture A, and a twin-screw extruder is used for extrusion granulation. The mixture A is fed from the main feed port of the twin-screw extruder, and the alkali-free short-cut fiber is fed from the side feed port of the twin-screw extruder. The high CTI and high GWIT flame-retardant reinforced PPE / PA6 material is added from the main feed of the twin-screw extruder, and the glass fiber is added from the side feed. After melt extrusion, granulation, drying and other processes, a high CTI value halogen-free flame retardant reinforced PPE / PA6 composition is obtained.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention uses specific hydroxyapatite as a CTI enhancing agent, and uses linear low-density polyethylene and a specific black colorant (aniline black) in combination. The prepared product can achieve a CTI level of 0, and at the same time has excellent mechanical properties and flame retardant properties, and has no significant difference from existing conventional products.

[0017] (2) The present invention adopts a high-fluidity PPE resin and a high-fluidity PA6 resin for compounding, so that the PPE / PA6 composition can have good appearance, dimensional stability, low warpage and excellent processing fluidity.

[0018] (3) The present invention uses microcapsules with PA6 resin as a carrier to coat the red phosphorus flame retardant masterbatch, and optimizes the addition ratio of PPE resin and PA6 resin, so that the prepared product has excellent flame retardant properties under the condition of a lower flame retardant addition amount. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] High fluidity PPE resin, manufacturer: Zhongmu; brand: ZM-035

[0021] High fluidity PA6 resin, manufacturer: Xinhui Meida; brand: M2000

[0022] Glass fiber, manufacturer: Chongqing International; brand: 301HP-3-H

[0023] Halogen-free flame retardant, microencapsulated red phosphorus masterbatch, manufacturer: Tongcheng Xinde; brand: FR4140

[0024] Compatibilizer, maleic anhydride grafted PPE, manufacturer: Jiayirong; brand: FB820

[0025] Elastomer #1, SEBS, manufacturer: Li Changrong; brand: 7554

[0026] Elastomer #2, maleic anhydride grafted POE elastomer, manufacturer: Nengzhiguang New Materials; brand: N413A

[0027] Linear low-density polyethylene, manufacturer: Zhejiang Petrochemical; brand: DNDA-8320

[0028] CTI lifting agent, hydroxyapatite, commercially available

[0029] Antioxidant #1, manufacturer: Lianlong; brand: THANOX 1010

[0030] Antioxidant #2, manufacturer: DOVER CHEMICAL; brand: S-9228

[0031] Colorant #1, aniline black masterbatch, commercially available

[0032] Colorant #2, carbon black masterbatch, commercially available

[0033] According to the formula dosage (parts by weight) in the specific examples 1-7 and comparative examples 1-7 described in Table 1, high-flow PPE, high-flow PA6, toughening agent, halogen-free flame retardant, compatibilizer, glass fiber, CTI enhancing agent, linear low-density polyethylene and other additives are weighed respectively. The components except glass fiber and halogen-free flame retardant are put into a high-speed mixer and mixed until uniform to obtain premix A; then the obtained premix A is put into a twin-screw extruder from the main feeding port, and the glass fiber and halogen-free flame retardant are respectively put into the twin-screw extruder from two side feeds by a side feeding process, and a high CTI value halogen-free flame retardant reinforced PPE / PA6 composition is obtained after melt extrusion, granulation, drying and other processes.

[0034] The relevant performance tests were carried out according to the following test methods. The test results are shown in Table 2.

[0035] (1) Tensile strength: according to ISO 527 method, the specimen size is 170*10*4mm, and the test speed is 50mm / min;

[0036] (2) Notched impact strength: according to ISO 179 / 1eA method, specimen size 80*10*4mm;

[0037] (3) CTI test: Using IEC60112 standard, the test uses a φ50*4mm disc, ammonium chloride as the electrolyte, and a resistivity of 3.95*10 2 Ωcm, calibration current is 1.0A

[0038] (4) Vertical flammability: According to the UL94 method, the sample size is 125*10*1.6mm, and the vertical flammability of the 1.6mm thick test piece is tested. The vertical flammability that meets the UL94 V-0 level is marked as OK, and the vertical flammability that does not meet the UL94 V-0 level is marked as NG.

[0039] Table 1 Component ratios of high CTI value halogen-free flame retardant reinforced PPE / PA6 compositions in the examples and comparative examples

[0040]

[0041]

[0042] Table 2 Test results of high CTI value halogen-free flame retardant reinforced PPE / PA6 compositions in the examples and comparative examples

[0043]

[0044] It can be seen from Table 1 and Table 2 that the high CTI value halogen-free flame retardant reinforced PPE / PA6 composition of the present invention has good comprehensive performance, and each product can reach the CTI level of Class 0. It can be seen from Comparative Example 1 that the CTI performance of conventional halogen-free flame retardant reinforced PPE / PA6 is poor, only 350V. It can be seen from Example 1, Example 3 and Comparative Examples 4-5 that hydroxyapatite can significantly improve the CTI value of the halogen-free flame retardant reinforced PPE / PA6 composition, but when too little hydroxyapatite is introduced, the CTI value of the product is limited and fails to reach the CTI level of Class 0. As the amount of hydroxyapatite added gradually increases, the CTI value of the product is greater than 600V, reaching the CTI level of Class 0. It can be seen from Example 1 and Comparative Examples 2-3 that linear low-density polyethylene has a certain degree of improvement on the CTI value of the product. For black-colored halogen-free flame retardant reinforced PPE / PA6 products, the choice of black colorant has a great influence on the CTI value of the product. When conventional inorganic carbon black colorant is added, the CTI value of the product is less than 600V. When the black colorant is aniline black, the CTI value of the product can reach up to 700V, meeting the CTI level of Class 0.

[0045] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A high CTI value halogen-free flame retardant reinforced PPE / PA6 composition, characterized in that: The invention is composed of the following raw materials calculated by mass percentage: high fluidity PPE 7-30%, high fluidity PA6 20-40%, toughening agent 3-10%, halogen-free flame retardant 4-8%, compatibilizer 3-7%, glass fiber 20-50%, CTI improving agent 2-5%, linear low density polyethylene 1.3-1.7% and other additives 1-5%.

2. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The high-fluidity PPE resin has an intrinsic viscosity of 0.33-0.37 dl / g, a melt flow rate (315°C, 10kg) of 45-65 g / 10min, and a notched impact strength of ≥3 kJ / m 2 .

3. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The high-fluidity PA6 resin has a relative viscosity of 2.0, a melt flow rate (230°C, 2.16kg) of 100-120g / 10min, and a notched impact strength of ≥5kJ / m 2 .

4. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The toughening agent is at least one of a SEBS elastomer and a maleic anhydride grafted POE elastomer.

5. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 4, characterized in that: The SEBS elastomer is a linear transparent SEBS, the styrene content of which is 29.5-32.5% by mass, and the toluene viscosity (10% / 25° C.) is 300-500 cp.

6. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 4, characterized in that: The maleic anhydride grafted POE elastomer has a functional group content of 0.4%-0.8% by mass, and a melt flow rate (190° C., 2.16 kg) of 0.5-2.5 g / 10 min.

7. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted PPE, and its density is 1.06g / cm 3 The maleic anhydride grafting rate is 0.7-0.9% by mass.

8. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The halogen-free flame retardant is a microcapsule-coated red phosphorus flame retardant with PA6 resin as the carrier and a density of 1.40-1.60 g / cm 3 , phosphorus content is 40-45%, and the ignition point is ≥320℃.

9. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The CTI improving agent is hydroxyapatite, which has a volume density of 22 g / 1, a CaO content of 55% by mass, a P2O5 content of 41% by mass, a pH value of 7, and a particle size (d 50 ) is 3.1μm.

10. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The glass fiber is an alkali-free glass fiber with an average diameter of 1 to 20 μm and an average length of 1 to 10 mm.

11. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The linear low-density polyethylene has a melt flow rate (190°C, 2.16kg) of 18-22g / 10min and a notched impact strength of ≥53kJ / m 2 .

12. The high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to claim 1, characterized in that: The other auxiliary agents include aniline black material, with PA6 resin as a carrier, and the aniline black content is 40%.

13. The method for preparing the high CTI value halogen-free flame retardant reinforced PPE / PA6 composition according to any one of claims 1 to 12, characterized in that: The steps are: The weighed high-flowability PPE resin, high-flowability PA6 resin, compatibilizer, toughening agent, halogen-free flame retardant, CTI improving additive, linear low-density polyethylene and other additives are mixed evenly in a high-speed mixer to obtain a mixture A, which is extruded and granulated by a twin-screw extruder. The mixture A is fed from the main feed port of the twin-screw extruder, and the alkali-free short-cut fiber is fed from the side feed port of the twin-screw extruder. The high CTI halogen-free flame retardant reinforced PPE / PA6 material is added from the main feed of the twin-screw extruder, and the glass fiber is added from the side feed. After melt extrusion, granulation, drying and other processes, a high CTI value halogen-free flame retardant reinforced PPE / PA6 composition is obtained.

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