High-flowability and high-CTI halogen-free flame-retardant polyamide composite material and preparation method thereof

Abstract

The invention discloses a high-flowability and high-CTI (comparative tracking index) halogen-free flame-retardant polyamide composite material and a preparation method thereof, and belongs to the field of polymer composite materials. The high-flowability and high-CTI halogen-free flame-retardant polyamide composite material is prepared from the following components in parts by weight: 20 to 60 parts of polyamide resin, 1 to 20 parts of benzene ring-containing polyamide resin, 1 to 10 parts of polyester resin, 10 to 50 parts of glass fiber, 10 to 20 parts of halogen-free flame retardant, 1 to 15 parts of flame-retardant synergist, 0.5 to 3 parts of antioxidant and 0.5 to 2 parts of lubricant. Under the interaction of a plurality of polyamides and polyester alloys and the synergistic effect of a plurality of flame-retardant synergists, the flame-retardant polyamide composite material not only has excellent mechanical properties and flame retardancy, but also has excellent material flowability and tracking resistance; therefore, the composite material has a good prospect in new energy, electronic and electrical appliances and other related applications requiring thin-wall forming and higher electrical insulation.

Description

Technical Field

[0001] The invention belongs to the field of polymer composite materials, and in particular relates to a high-flowability, high-CTI halogen-free flame-retardant polyamide composite material and a preparation method thereof. Background Art

[0002] In recent years, with the development of home appliances, automobiles, consumer electronics and other industries, the insulation performance requirements for halogen-free flame retardant reinforced engineering plastics have become increasingly higher, especially halogen-free flame retardant reinforced polyamide materials have been widely used in these industries. In the use of electronic and electrical equipment, fires caused by leakage, short circuit, arc, sparks and other reasons have caused serious harm to people's lives and production. Especially in small electrical equipment, dense pins require plastic materials to have a very high comparative tracking index (CTI). The CTI of conventional bromine-based flame retardant polyamide materials is usually lower than 300V, which is difficult to meet safety requirements. Although the CTI of conventional halogen-free flame retardant polyamide materials can reach 600V, its stability is low, and the polyamide may also decrease after absorbing water, and the risk of use will also increase. In addition, new energy vehicles have developed rapidly in recent years, and the voltage platform has also developed from 400V to 800V or even higher, which also puts higher requirements on the electrical insulation performance of flame retardant polyamide materials.

[0003] The patent application with publication number CN 106009638 A discloses a halogen-free flame retardant reinforced nylon 6 composite material and its preparation method. By adopting a multi-component compounded halogen-free flame retardant, the flame retardant grade of the material reaches UL-94V0 level, while maintaining a high tracking index (CTI value) and excellent comprehensive mechanical properties. However, this method causes serious wear on the equipment during the processing, and the length and dispersion uniformity of the glass fiber are not easy to control. Therefore, in order to meet the rapid development needs of home appliances, electronic appliances, and new energy vehicles, it is urgent to develop a high-flow, high-CTI halogen-free flame retardant polyamide composite material. Summary of the invention

[0004] The object of the present invention is to provide a high-flowability, high-CTI halogen-free flame-retardant polyamide composite material and a preparation method thereof, so as to improve the tracking resistance of the halogen-free flame-retardant polyamide composite material.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A high-flowability, high-CTI halogen-free flame-retardant polyamide composite material comprises, by weight, 20-60 parts of polyamide resin, 5-20 parts of polyamide resin containing benzene rings, 5-10 parts of polyester resin, 10-50 parts of glass fiber, 10-20 parts of halogen-free flame retardant, 1-15 parts of flame retardant synergist, 0.5-3 parts of antioxidant and 0.5-2 parts of lubricant.

[0007] Furthermore, the polyamide resin is one or a combination of PA6, PA66, PA66 / 6, PA6 / 66, and PA56.

[0008] Furthermore, the polyamide resin is PA66.

[0009] Furthermore, the benzene ring-containing polyamide resin is one or a combination of PA66 / 6I, PA66 / 6T, PA6I / 6T, PA6T / 66, PA6T / 6I, PA6T / 6I / 66, PA6T / 5T, PA6T / 10T, and MXD6.

[0010] Furthermore, the polyamide resin containing benzene rings is one or a combination of PA66 / 6I, PA66 / 6T, PA6I / 6T, and PA6T / 66.

[0011] Furthermore, the polyester resin is one or more of PET, PBT, PCT, PTT, PETG, PEN (polyethylene naphthalate), and PBN (polybutylene naphthalate).

[0012] Furthermore, the polyester resin is PET, PBT, or PCT.

[0013] Furthermore, the diameter of the glass fiber is 7 μm to 13 μm.

[0014] Furthermore, the glass fiber has a diameter of 10 μm.

[0015] Furthermore, the halogen-free flame retardant is one or a combination of aluminum hypophosphite, aluminum monoethylphosphinate, aluminum diethylphosphinate, aluminum ethylbutylphosphinate, aluminum dibutylphosphinate, and aluminum ethylhexylphosphinate.

[0016] Furthermore, the halogen-free flame retardant is one or a combination of aluminum hypophosphite, aluminum monoethylphosphinate, aluminum diethylphosphinate, aluminum ethylbutylphosphinate, and aluminum dibutylphosphinate.

[0017] Furthermore, the halogen-free flame retardant is aluminum diethylphosphinate.

[0018] Furthermore, the flame retardant synergist is one or a combination of aluminum phosphite, aluminum hypophosphite, melamine polyphosphate (MPP), melamine pyrophosphate, melamine cyanurate (MCA), zinc borate, zinc stannate, zinc phosphate, zinc pyrophosphate, magnesium borate, and calcium stannate.

[0019] Furthermore, the flame retardant synergist is one or a combination of aluminum phosphite, MPP, MCA, and zinc borate.

[0020] Furthermore, the flame retardant synergist is aluminum phosphite or MPP.

[0021] Furthermore, the antioxidant is one of antioxidant 1098 and antioxidant 168, or a combination of both.

[0022] Furthermore, the lubricant is lubricant BN-500.

[0023] A method for preparing a high-flow, high-CTI halogen-free flame-retardant polyamide composite material comprises the following steps:

[0024] The polyamide resin, the polyamide resin containing a benzene ring, the polyester resin, the flame retardant synergist, the antioxidant and the lubricant are uniformly mixed in a high-speed mixer according to a proportion to obtain a mixture, and then the mixture is added into a twin-screw extruder through a main feed, a halogen-free flame retardant through a No. 1 side feed, and glass fiber through a No. 2 side feed, melt blended, extruded and granulated to obtain a high-flowability, high-CTI halogen-free flame retardant polyamide composite material.

[0025] Furthermore, the heating temperatures of the extruder are as follows: 240-300° C. for zones 1-3, 220-280° C. for zones 4-7, 230-290° C. for zones 8-10 and 240-300° C. for the die.

[0026] Beneficial effects of the present invention:

[0027] (1) The present invention provides a halogen-free flame-retardant glass fiber reinforced polyamide composite material, which uses sufficient raw material sources, all of which can be domestically produced, and has simple and stable process conditions. It also ensures excellent mechanical properties and flame retardant properties of the composite material while achieving high fluidity and high CTI of the product, and the overall cost performance of the material is still high.

[0028] (2) The molecular chain segments of the polyamide resin containing benzene rings used in the present invention contain certain aromatic ring structures, which can effectively improve the carbonization ability of polyamide materials and thus improve the flame retardant efficiency of polyamide halogen-free flame retardant materials; moreover, due to the conjugation effect of the aromatic ring and the amide bond, the chemical bond strength of the aromatic polyamide is improved, thereby improving the stability of the polyamide molecules at higher voltages, and further improving the CTI of the material. On the other hand, the polyamide resin used has excellent mechanical properties and has a similar structure to the polyamide resin containing benzene rings, and has good compatibility.

[0029] (3) The polyester resin used in the present invention can reduce the crystallization rate of the polyamide material after forming an alloy with the polyamide, thereby improving the molding fluidity of the material, which will be more advantageous in the application of thin-walled products; the halogen-free flame retardant used is compounded into the polyamide system, which can improve the flame retardant properties of the polyamide material through the solid-phase flame retardant mechanism, while having little effect on the mechanical properties of the material; the flame retardant synergist used is compounded with the halogen-free flame retardant to improve the flame retardant efficiency of the halogen-free flame retardant, reduce costs, and improve the mechanical properties of the material. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional means in the prior art, and thus will not be described in detail. The parts in the following embodiments are all parts by weight.

[0032] The models and suppliers of the raw materials used in this embodiment are as follows:

[0033] Polyamide resin: EPR27, PA66, Pingdingshan Shenma.

[0034] Polyamide resin containing benzene ring: PPA 1252, PA6T / 66, Qingdao Sanli.

[0035] Polyester resin: FG600, PET, Yizheng Chemical Fiber.

[0036] Glass fiber: ECS10-03-568H, boulder. (diameter 10μm)

[0037] Halogen-free flame retardant: OP1230, aluminum diethylphosphinate, Clariant.

[0038] Flame retardant synergist: Melapur 200 / 70, MPP, BASF.

[0039] Antioxidants: 1098 and 168 are both commercially available.

[0040] Lubricant: BN-500, Qingdao Bangni Chemical Co., Ltd.

[0041] The models and suppliers of the above raw materials are only for illustrating the sources and components of the raw materials used in the experiments of the present invention so as to fully disclose the information, and do not mean that the present invention cannot be realized by using other raw materials of the same type or raw materials provided by other suppliers.

[0042] Embodiment and comparative example:

[0043] According to the weight proportions in Table 1, PA66 resin EPR27, PA6T / 66 resin PPA1252, PET resin FG600, glass fiber ECS10-03-568H, halogen-free flame retardant OP1230, flame retardant synergist Melapur 200 / 70, antioxidant 1098, antioxidant 168 and lubricant BN-500 were weighed.

[0044] EPR27, PPA 1252, FG600, Melapur 200 / 70, antioxidant 1098, antioxidant 168 and lubricant BN-500 are mixed uniformly in a high mixer according to the proportion to obtain a mixture, and then the mixture is added to a twin-screw extruder through the main feed, OP1230 through the first side feed, and ECS10-03-568H through the second side feed, melt blended, and extruded into granules. The heating temperature of the extruder is set as follows: 260-290°C in zones 1-3, 250-270°C in zones 4-7, 260-280°C in zones 8-10, and 270-280°C in the die. The above raw materials are fully melt blended in a twin-screw extruder, extruded into granules, and a high-flow, high-CTI halogen-free flame-retardant polyamide composite material is obtained.

[0045] Table 1. Specific proportions of each composition in Examples 1-5 and Comparative Examples 1-3 (parts by weight)

[0046]

[0047]

[0048] Test method or standard:

[0049] Flame retardant performance test: The polyamide composite material of the embodiment or comparative example was dried at 120° C. for 4 hours and then tested by standard injection molding. The flame retardant performance test was performed on a sample with a thickness of 0.8 mm according to the UL-94 standard.

[0050] Relative tracking index (CTI) test: The polyamide composite material of the embodiment or comparative example was dried at 120°C for 4 hours and then tested according to standard injection molding. The test was performed according to IEC 60112-2020 standard, the sample size was 100*100*3mm, and the instrument test range was 0-1000V.

[0051] Flow ratio test: After the polyamide composite material of the embodiment or comparative example is dried at 120° C. for 4 h, continuous injection molding is performed using a flow ratio mold with a scale to test the flow ratio of the material, and the mold temperature is set to 90° C.

[0052] The high flowability, high CTI halogen-free flame retardant polyamide composite materials prepared in the above examples and comparative examples were tested for performance, and the results are shown in Table 2:

[0053] Table 2. Performance test results of materials of Examples 1-5 and Comparative Examples 1-3

[0054]

[0055] Combining the material ratios in Table 1 and the test results in Table 2, it can be seen from the comparison of Examples 1-4 and Comparative Example 3 that the addition of PA6T / 66 can improve the tensile and bending strength of the halogen-free flame retardant polyamide material, and can significantly improve the CTI of the halogen-free flame retardant polyamide material, and the CTI can stably reach 700V or even higher, but the flow length ratio of the material is reduced to a certain extent, indicating that the addition of PA6T / 66 will have a negative impact on the fluidity of the material. Comparing Example 2 and Comparative Example 2, it is shown that the addition of PET can improve the fluidity of the halogen-free flame retardant polyamide material. The principle is mainly that after PET and polyamide form an alloy, the crystallization rate of the polyamide material can be reduced, thereby improving the molding fluidity of the material, which will be more advantageous in the application of thin-walled products. Comparing Examples 1-5 and Comparative Examples 1 and 3, it can be seen that with PA66 as the matrix or the alloy of PA66 and PET as the matrix, the CTI value of the material is difficult to reach 700V.

[0056] In summary, the present invention provides a high-flowability, high-CTI halogen-free flame-retardant polyamide composite material and a preparation method thereof. The prepared halogen-free flame-retardant polyamide composite material not only has excellent mechanical properties and flame retardant properties, but also has excellent material fluidity and resistance to leakage tracking. Therefore, it will have a good prospect in related applications such as new energy, electronic appliances, etc. that require thin-wall molding and higher electrical insulation.

[0057] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0058] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high flow, high CTI halogen-free flame retardant polyamide composite material, characterized in that: By weight, it includes 20-60 parts of polyamide resin, 5-20 parts of polyamide resin containing benzene ring, 5-10 parts of polyester resin, 10-50 parts of glass fiber, 10-20 parts of halogen-free flame retardant, 1-15 parts of flame retardant synergist, 0.5-3 parts of antioxidant and 0.5-2 parts of lubricant.

2. The high flow, high CTI halogen-free flame retardant polyamide composite material according to claim 1, characterized in that: The polyamide resin is one or a combination of PA6, PA66, PA66 / 6, PA6 / 66, and PA56.

3. The high flow, high CTI halogen-free flame-retardant polyamide composite material according to claim 1, characterized in that: The benzene ring-containing polyamide resin is one or a combination of PA66 / 6I, PA66 / 6T, PA6I / 6T, PA6T / 66, PA6T / 6I, PA6T / 6I / 66, PA6T / 5T, PA6T / 10T, and MXD6.

4. The high flow, high CTI halogen-free flame-retardant polyamide composite material according to claim 1, characterized in that: The polyester resin is one or more of PET, PBT, PCT, PTT, PETG, PEN, and PBN.

5. The high flow, high CTI halogen-free flame-retardant polyamide composite material according to claim 1, characterized in that: The diameter of the glass fiber is 7 μm to 13 μm.

6. The high flow, high CTI halogen-free flame-retardant polyamide composite material according to claim 1, characterized in that: The halogen-free flame retardant is one or a combination of aluminum hypophosphite, aluminum monoethylphosphinate, aluminum diethylphosphinate, aluminum ethylbutylphosphinate, aluminum dibutylphosphinate, and aluminum ethylhexylphosphinate.

7. The high flow, high CTI halogen-free flame-retardant polyamide composite material according to claim 1, characterized in that: The flame retardant synergist is one or a combination of aluminum phosphite, aluminum hypophosphite, melamine polyphosphate, melamine pyrophosphate, melamine cyanurate, zinc borate, zinc stannate, zinc phosphate, zinc pyrophosphate, magnesium borate, and calcium stannate.

8. The high flow, high CTI halogen-free flame-retardant polyamide composite material according to claim 1, characterized in that: The antioxidant is one or a combination of antioxidant 1098 and antioxidant 168; the lubricant is lubricant BN-500.

9. A method for preparing a high-flow, high-CTI halogen-free flame-retardant polyamide composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: The polyamide resin, the polyamide resin containing a benzene ring, the polyester resin, the flame retardant synergist, the antioxidant and the lubricant are uniformly mixed to obtain a mixture; the mixture, the halogen-free flame retardant and the glass fiber are melt-blended, extruded and granulated to obtain a high-flowability, high-CTI halogen-free flame retardant polyamide composite material.

10. The method for preparing a high-flowability, high-CTI halogen-free flame-retardant polyamide composite material according to claim 9, characterized in that: The heating temperatures of the extruder in the extrusion granulation are as follows: 240-300° C. in zones 1-3, 220-280° C. in zones 4-7, 230-290° C. in zones 8-10 and 240-300° C. in the die.

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