A halogen-free flame-retardant polycarbonate composition and its preparation method and application

Abstract

The present invention discloses a halogen-free flame-retardant polycarbonate composition, its preparation method, and application. The halogen-free flame-retardant polycarbonate composition comprises the following components, by weight: 80-95 parts of a polycarbonate resin; 0.1-15 parts of a flame retardant; 0.4-1.2 parts of an anti-drip agent; 0.2-2 parts of an organosiloxane; and 0.2-1.2 parts of a UV absorber. The halogen-free flame-retardant polycarbonate composition provided by the present invention not only has good flame retardancy but also has a high Compensation for Temperature (CTI) value, making it suitable for use in products requiring high flame retardancy and CTI values.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering plastics, and in particular to a halogen-free flame-retardant polycarbonate composition, a preparation method thereof and an application thereof. Background Art

[0002] Polycarbonate (PC) is a non-crystalline thermoplastic engineering plastic with excellent performance. It has outstanding impact resistance, heat resistance, good dimensional stability and low water absorption. It is widely used in home appliances, office equipment, electronic appliances and other fields.

[0003] However, because the PC backbone contains a large number of benzene rings, when discharge occurs on the PC surface, the benzene ring structure changes, forming a conductive carbon layer. Electrical materials generally use flame-retardant materials, and the halogen-free flame retardants used in PC, such as phosphate esters, promote the formation of the carbon layer. However, the carbon layer is a good conductor of current, which leads to poor tracking performance (CTI) of flame-retardant PC, generally not exceeding 250V. Therefore, to meet user needs, it is necessary to develop high CTI flame-retardant polycarbonate alloy products. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention proposes a halogen-free flame-retardant polycarbonate composition and its preparation method and application. The specific technical solution is as follows:

[0005] A halogen-free flame-retardant polycarbonate composition comprises the following components in parts by weight:

[0006]

[0007] Furthermore, the organosiloxane is a fluorine-containing side group organosiloxane, such as poly(nonafluorohexyl)siloxane, poly(heptadecafluorodecyl)methylsiloxane, polymethyl(trifluoropropyl)siloxane, etc. Fluorine-containing side group organosiloxanes such as poly(nonafluorohexyl)siloxane, poly(heptadecafluorodecyl)methylsiloxane, and polymethyl(trifluoropropyl)siloxane can ensure that PC has good flame retardant properties while further improving the CTI value. Organosiloxanes have low surface energy and tend to accumulate on the surface of the product. Due to their large water contact angle, they are not easily wetted by the electrolyte, thereby significantly improving the CTI performance of the PC material. Introducing fluorine groups into the side groups can further increase the water contact angle, thereby further improving the CTI of the material.

[0008] Furthermore, the ultraviolet absorber is one or more of benzophenone, benzotriazole, triazine or oxalyl dianilide ultraviolet absorbers.

[0009] Preferably, the UV absorber is a triazine. The triazine UV absorber can be one or more of 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxy-phenol, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-octyloxyphenol, or 2-[4,6-bis(4-biphenyl)-1,3,5-triazin-2-yl]-5-[(2-ethylhexyl)oxy]phenol. Triazine UV absorbers commonly used in the art can further improve the CTI value of the PC composition of the present invention.

[0010] During the CTI test, the discharge between the two electrodes will generate a large amount of high-energy ultraviolet light, which will accelerate the aging, degradation and carbonization of the material. The addition of ultraviolet absorbers can form a second barrier to the material performance and synergize with organosiloxane to improve the CTI performance of PC materials. Triazine ultraviolet absorbers are preferred. Triazine ultraviolet absorbers have higher ultraviolet light absorption efficiency and more significant effect on improving CTI performance.

[0011] Furthermore, the mass ratio of the organosiloxane to the ultraviolet absorber is (0.2-2):(0.2-1.2).

[0012] Furthermore, the weight average molecular weight of the polycarbonate resin is 17,000-30,000. When the weight average molecular weight of the polycarbonate resin is 17,000, 18,000, 20,000, 22,000, 24,000, 26,000, 28,000, or 30,000, the flame retardant properties and CTI value of the PC composition of the present invention can be better guaranteed.

[0013] Furthermore, the flame retardant is one or more of a sulfonate flame retardant, a phosphate flame retardant or a phosphorus-nitrogen flame retardant.

[0014] Furthermore, the anti-dripping agent is polytetrafluoroethylene.

[0015] The present invention also provides a method for preparing the halogen-free flame-retardant polycarbonate composition, comprising the following steps:

[0016] S1: Weigh and pre-mix the components according to the ratio to obtain a premix;

[0017] S2: putting the premix of step S1 into an extruder, performing melt blending and extrusion granulation to obtain the halogen-free flame retardant polycarbonate composition.

[0018] Furthermore, the extruder is a twin-screw extruder, the screw length-diameter ratio of the twin-screw extruder is (40-48):1, the barrel temperature of the twin-screw extruder is 200-280°C, and the screw speed of the twin-screw extruder is 300-600r / min.

[0019] The present invention also provides the use of the halogen-free flame-retardant polycarbonate composition in the preparation of electronic appliances, such as lighting equipment, low-voltage electrical appliances, household appliances, power tools, electronic instruments, electrical meters, etc.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention uses organosiloxane to improve the CTI of PC materials, and simultaneously adds a specific amount of ultraviolet absorber to synergistically improve the CTI performance of the PC material with the organosiloxane, thereby preparing a halogen-free flame retardant polycarbonate composition that not only has good flame retardant properties but also has a high CTI value. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 making any creative efforts are within the scope of protection of the present invention.

[0023] <Preparation of Examples and Comparative Examples>

[0024] The raw materials used in the examples and comparative examples of the present invention are all commercially available, but are not limited to these materials:

[0025] Polycarbonate resin A: weight average molecular weight 17000, brand PC FN1700, purchased from Formosa Chemical Corporation Idemitsu;

[0026] Polycarbonate resin B: weight average molecular weight 30,000, brand PC 2030, purchased from Wanhua Chemical;

[0027] Flame retardant A: sulfonate flame retardant, brand SC4, purchased from Sinochem;

[0028] Flame retardant B: phosphate flame retardant, brand WSFR-BDP-N2, purchased from Wansheng;

[0029] Organosiloxane A: polydimethylsiloxane;

[0030] Organosiloxane B: poly(nonafluorohexyl)siloxane;

[0031] Organosiloxane C: Polymethyl (trifluoropropyl) siloxane

[0032] UV absorber A: benzotriazole, brand Chi guard 234, purchased from Qitai Chemical;

[0033] UV absorber B: triazine, brand Chi guard 1064, purchased from Qitai Chemical;

[0034] Anti-dripping agent: polytetrafluoroethylene, commercially available. Parallel experiments used the same commercial product.

[0035] The preparation methods of the embodiments of the present invention and the comparative examples are as follows:

[0036] S1: According to the ratios in Table 1 and Table 3, weigh and pre-mix the components to obtain a premix;

[0037] S2: putting the premix of step S1 into a twin-screw extruder for melt blending and extrusion granulation to obtain a halogen-free flame retardant polycarbonate composition.

[0038] The screw length-diameter ratio of the twin-screw extruder is 40:1, the barrel temperature of the twin-screw extruder is 260°C, and the screw speed of the twin-screw extruder is 400 r / min.

[0039] <Test Standard>

[0040] The performance test standards of the embodiments and comparative examples of the present invention are as follows:

[0041] CT I: tested according to standard IEC 60112-2020;

[0042] Fire test: tested in accordance with UL94-2018 standard, the thickness of the test sample is 2.0mm.

[0043] Table 1. Formula of Examples 1-7 (parts by weight)

[0044]

[0045] Table 2. Performance test results of Examples 1-7

[0046]

[0047] Table 3. Comparative Examples 1-4 Formula (parts by weight)

[0048]

[0049]

[0050] Table 4. Performance test results of comparative examples 1-4

[0051]

[0052] Comparing Comparative Example 1 with Example 3, while no flame retardant was added, the CTI value of Comparative Example 1 increased, but the flame retardancy rating decreased significantly. This is because flame retardants have a negative effect on CTI. Without the addition of flame retardants, the CTI value would be high, but the flame retardancy rating would not meet industry requirements. In the present invention, the CTI rating is increased by adding an appropriate amount of flame retardants and specific components such as organosiloxanes and UV absorbers. This overcomes the problem of low CTI in flame-retardant materials due to the flame retardant's enhanced carbonization, while also ensuring the flame retardant properties of the PC composition of the present invention.

[0053] Compared with Example 3, Comparative Example 2 does not add organosiloxane, resulting in a decrease in the CTI value of Comparative Example 2.

[0054] Compared with Example 3, Comparative Example 3 does not add an ultraviolet absorber, and the CTI value of Comparative Example 3 is also lower.

[0055] Compared with Example 3, Comparative Example 4 does not add organosiloxane and ultraviolet absorber, and the CTI of Comparative Example 4 decreases sharply.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A halogen-free flame retardant polycarbonate composition, characterized in that: Calculated by weight, it includes the following components: 80-95 parts of polycarbonate resin; 0.1-15 parts of flame retardant; 0.4-1.2 parts of anti-dripping agent; 0.2-2 parts of organosiloxane; 0.2-1.2 parts of ultraviolet absorber; The organosiloxane is a fluorine-containing side group organosiloxane; The weight average molecular weight of the polycarbonate resin is 17000-30000; The ultraviolet absorber is one or more of benzotriazole and triazine ultraviolet absorbers.

2. The halogen-free flame retardant polycarbonate composition according to claim 1, characterized in that The ultraviolet absorber is a triazine.

3. The halogen-free flame retardant polycarbonate composition according to claim 1, characterized in that The flame retardant is one or more of a sulfonate flame retardant, a phosphate flame retardant or a phosphorus-nitrogen flame retardant.

4. The halogen-free flame retardant polycarbonate composition according to claim 1, characterized in that The anti-dripping agent is polytetrafluoroethylene.

5. A method for preparing the halogen-free flame-retardant polycarbonate composition according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Weigh and pre-mix the components according to the ratio to obtain a premix; S2: putting the premix of step S1 into an extruder, performing melt blending and extrusion granulation to obtain the halogen-free flame retardant polycarbonate composition.

6. Use of the halogen-free flame retardant polycarbonate composition according to any one of claims 1 to 4 in the preparation of electronic appliances.

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