Modified polycarbonate composition with excellent flame retardant property and preparation method thereof

Abstract

The invention relates to a polycarbonate composition with excellent flame retardant property. The polycarbonate composition comprises the following main components: 70 to 85 parts of polycarbonate, 13 to 28 parts of a polysiloxane-polycarbonate random copolymer, 0.3 to 0.6 part of an antioxidant, 0.2 to 0.6 part of a flame retardant, 0.5 to 0.8 part of an anti-dripping agent and 0.5 to 0.6 part of a lubricant. The preparation method comprises the following steps: putting the polycarbonate into a charging basket, sequentially adding the polysiloxane polycarbonate random copolymer, the antioxidant, the flame retardant, the anti-dripping agent and the lubricant, manually stirring, adding into a V-shaped mixer, uniformly mixing, and adding into a double-screw extruder bin; and starting a feeding screw to push the mixture into a double-screw extruder at a constant speed, carrying out melt extrusion molding, cooling, blow-drying, and granulating. The polycarbonate composition which is excellent in flame retardant property and easy to demould in the processing process can be widely applied to the application fields with higher requirements on flame retardant property, especially to the flame retardant application of cable wiring pipes, wiring boxes and the like.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and in particular relates to a modified polycarbonate composition with excellent flame retardancy and a preparation method thereof. Background Art

[0002] Polycarbonate (PC) is a thermoplastic organic polymer material. It can be divided into aliphatic, alicyclic and aromatic according to its chemical structure. At present, only bisphenol A aromatic polycarbonate has been industrialized, so polycarbonate materials generally refer to bisphenol A polycarbonate. Polycarbonate is the fastest growing general engineering plastic in recent years. It has a series of advantages such as good transparency and impact resistance, excellent light transmittance, and high glass transition temperature. It can still maintain good toughness in the range of -20℃~140℃. But there are also disadvantages. Due to the presence of benzene rings in the chemical structure, the melt has high viscosity and poor fluidity, which makes molding and processing difficult and prone to stress cracking, which limits the application of polycarbonate to a certain extent. Therefore, in terms of market application, it is generally modified first. With the increase in R&D investment in the modification industry and the continuous advancement of modification technology, the effect of polycarbonate in improving performance has become more and more obvious, which has promoted its wide application in various industries. Summary of the invention

[0003] The present invention aims to avoid the deficiencies of the prior art and applications, and provides a modified polycarbonate composition with excellent flame retardancy and a preparation method thereof.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a polycarbonate composition with excellent flame retardant properties, characterized in that it is prepared by mixing the following components in parts by weight: 70-85 parts of polycarbonate, 13-28 parts of polysiloxane-polycarbonate random copolymer, 0.3-0.6 parts of antioxidant, 0.2-0.6 parts of flame retardant, 0.5-0.8 parts of anti-dripping agent, and 0.5-0.6 parts of lubricant.

[0005] The method for preparing a polycarbonate composition with excellent flame retardant performance comprises the following specific steps: placing the main material polycarbonate in a material barrel, adding polysiloxane-polycarbonate random copolymer, antioxidant, flame retardant, anti-dripping agent and lubricant in sequence, adding the mixture to a V-type mixer after manual stirring, adding the mixture to a twin-screw extruder silo after mixing evenly; starting the feeding screw to push the mixture into the twin-screw extruder at a uniform speed, cooling after melt extrusion molding, blowing and granulating after drying, to obtain the polycarbonate composition.

[0006] The antioxidant is tris(2,4-di-tert-butylbenzene)phosphite or β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester.

[0007] The flame retardant is potassium 3-benzenesulfonylbenzenesulfonate.

[0008] The anti-dripping agent is specially modified polytetrafluoroethylene powder.

[0009] The lubricant is pentaerythritol stearate.

[0010] The principle of the present invention is that the molecular structure of ordinary bisphenol A polycarbonate is brittle due to the strong rigidity of the benzene ring, which is particularly obvious at low temperatures. The molecular structure of siloxane polycarbonate contains siloxane segments, which can not only retain the strength of polycarbonate but also overcome the low-temperature brittleness after being mixed with ordinary bisphenol A polycarbonate. In addition, the flame retardant performance of siloxane polycarbonate is better. Combined with a small amount of flame retardant and anti-dripping agent, the modified product has excellent flame retardant performance and low-temperature toughness.

[0011] The invention has the following beneficial effects: the preparation process is simple, the flame retardancy of polysiloxane carbonate is better than that of common polycarbonate, and due to the similarity of chemical structure, the two materials have good compatibility, and combined with the excellent flame retardancy of KSS, a small amount of KSS can achieve a V-0 flame retardancy effect, and because the small amount of addition has little effect on the performance of the composition, the weather resistance and high and low temperature resistance of the polymer are well maintained. It can be widely used in various complex environments with high flame retardancy requirements, especially in fields with high flame retardancy requirements such as cable wiring pipes and junction boxes. DETAILED DESCRIPTION

[0012] The embodiments of the present invention will be described in detail below with reference to examples.

[0013] A polycarbonate composition with excellent flame retardant performance, characterized in that it is prepared by mixing the following components in parts by weight: 70-85 parts of polycarbonate, 13-28 parts of polysiloxane-polycarbonate random copolymer, 0.3-0.6 parts of antioxidant, 0.2-0.6 parts of flame retardant, 0.5-0.8 parts of anti-dripping agent, and 0.5-0.6 parts of lubricant.

[0014] The raw material ratios of Examples 1-4 are shown in Table 1.

[0015] Specific raw material sources: Polycarbonate: PC8155 from Cangzhou Dahua Co., Ltd., melt flow rate 15 g / (10min).

[0016] Polysiloxane-polycarbonate random copolymer: Gansu Yinguang Polysilver Chemical Co., Ltd., melt flow rate 3g / (10min), weight of polysiloxane block 20%, molecular weight 28000~32000.

[0017] Antioxidants: tris(2,4-di-tert-butylbenzene) phosphite; β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0018] Flame retardant: KSS (potassium 3-phenylsulfonylbenzenesulfonate).

[0019] Anti-dripping agent: SN3300B3 (specially modified polytetrafluoroethylene powder).

[0020] Release lubricant: PETS (pentaerythritol stearate).

[0021] The specific steps of the preparation method are: The main material of polycarbonate is placed in a material barrel, and polysiloxane polycarbonate random copolymer, antioxidant, flame retardant, anti-dripping agent and lubricant are added in sequence. After manual stirring, the mixture is added to a V-type mixer, and after mixing evenly, the mixture is added to a silo of a twin-screw extruder; a feeding frequency of 6-14 HZ is given, and the feeding screw is turned on to push the mixture into the twin-screw extruder at a uniform speed, the extruder speed is 350-450rpm, the feeding section temperature is 150-220°C, the compression section temperature is 240-265°C, the metering section temperature is 260-250°C, the head temperature is 240°C, and the polycarbonate composition is obtained after melt extrusion molding, cooling, blow drying and granulation.

[0022] Analytical test methods: Mechanical properties test: The experimental pellets were placed in a drying oven at 100 °C for 2 h, and then the experimental samples were prepared by an injection molding machine. After the samples were placed at room temperature for 24 h, their mechanical properties were tested by a universal tensile testing machine and a digital impact testing machine.

[0023] Low-temperature performance specimen processing method: Place the notched impact specimen in a -40 ℃ freezer for 4 h, take out the low-temperature frozen specimen and place it in a digital impact testing machine to complete the impact test within 10 s.

[0024] Flame retardant performance test: Take 5 specimens and put them into a constant temperature and humidity test box at a temperature of 23±2 ℃ and a humidity of 50±5% for pretreatment for 2 hours. Then use the UL94 flame retardant test method and standard to test the flame retardant performance of the specimens in a horizontal and vertical burning test machine.

[0025] The test results are shown in Table 2 and Table 3.

[0026]

[0027] From the above data comparison, it can be seen that according to the raw material ratio in the present invention, the prepared modified polycarbonate composition has excellent mechanical properties in terms of tensile strength, room temperature toughness and low temperature toughness, and the flame retardant properties can reach V-0 level. In addition, with the increase of the ratio of polysiloxane-polycarbonate random copolymer, the tensile strength and elongation at break gradually decrease, and the room temperature and low temperature impact properties continue to increase. Among the flame retardant properties, Example 4 is the best, followed by Example 2. Comprehensively comparing the various embodiments, the mechanical properties and flame retardant properties of Example 2 are relatively excellent.

[0028] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A polycarbonate composition having excellent flame retardancy, characterized in that: The invention is prepared by mixing the following components in parts by weight: 70-85 parts of polycarbonate, 13-28 parts of polysiloxane-polycarbonate random copolymer, 0.3-0.6 parts of antioxidant, 0.2-0.6 parts of flame retardant, 0.5-0.8 parts of anti-dripping agent and 0.5-0.6 parts of lubricant.

2. The method for preparing a polycarbonate composition with excellent flame retardancy according to claim 1, characterized in that: The specific steps are as follows: placing the main material polycarbonate in a material barrel, adding polysiloxane-polycarbonate random copolymer, antioxidant, flame retardant, anti-dripping agent, and lubricant in sequence, adding the mixture to a V-type mixer after manual stirring, adding the mixture to a twin-screw extruder silo after mixing evenly; turning on the feeding screw to push the mixture into the twin-screw extruder at a uniform speed, cooling after melt extrusion molding, blowing dry, and then granulating to obtain a polycarbonate composition.

3. A polycarbonate composition with excellent flame retardancy as claimed in claim 1, characterized in that: The antioxidant is tris(2,4-di-tert-butylbenzene)phosphite or β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester.

4. A polycarbonate composition with excellent flame retardancy as claimed in claim 1, characterized in that: The flame retardant is potassium 3-benzenesulfonylbenzenesulfonate.

5. A polycarbonate composition with excellent flame retardancy as claimed in claim 1, characterized in that: The anti-dripping agent is specially modified polytetrafluoroethylene powder.

6. A polycarbonate composition with excellent flame retardancy as claimed in claim 1, characterized in that: The lubricant is pentaerythritol stearate.

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