A polycarbonate composition, its preparation method and application

Abstract

The present invention belongs to the field of polycarbonate materials, and specifically discloses a polycarbonate composition, a preparation method and an application thereof. The polycarbonate composition of the present invention comprises the following components in parts by weight: 100 parts of polycarbonate, 0.01 - 0.1 part of a sulfonate flame retardant, 0.1 - 0.8 part of a anti-dripping agent, and 0.01 - 0.1 part of an alkaline aqueous solution. In the polycarbonate composition containing a sulfonate flame retardant and an anti-dripping agent, the present invention adds a certain amount of an alkaline aqueous solution, which can enable the polycarbonate composition to have excellent vertical burning and needle flame burning properties, good mechanical strength, and meet the environmental protection requirements.

Description

Technical Field

[0001] The present invention belongs to the field of polycarbonates, and particularly relates to a polycarbonate composition, a preparation method thereof, and an application thereof. Background Art

[0002] Polycarbonate (PC) is an engineering plastic with excellent performance, having good comprehensive properties, such as high mechanical strength, good impact toughness, dimensional stability, good heat resistance, and good electrical insulation. It is widely used in fields such as household appliances, digital products, and IT products. The application of PC in these products also poses certain requirements for its flame retardancy.

[0003] Sulfonate flame retardant is an efficient polycarbonate flame retardant. Its mechanism of action is that the decomposition products of sulfonate during the initial stage of combustion promote the Fris rearrangement of polycarbonate, inducing the rapid formation of a dense carbon layer on the surface of the workpiece to isolate oxygen and heat and block the occurrence of combustion. The higher the addition amount of the flame retardant, the better the flame retardant effect. However, currently, this flame retardant has been regulated by REACH environmental protection, and the material addition amount is required to be controlled within 1000 ppm. Therefore, the flame retardancy level of polycarbonate in this flame retardant system has limitations.

[0004] For products in industries such as audio and communication, the mandatory national standard GB4943.1-2022 "Audio, Video, Information Technology, and Telecommunication Technology Equipment - Part 1: Safety Requirements" was officially promulgated on July 19, 2022, comprehensively replacing the requirements of GB4943.1-2011 and GB 8898-2011. The changes regarding material flame retardancy in it have added extremely stringent needle flame test requirements. Existing commercially available halogen-free flame retardant PC materials cannot meet the needle flame test requirements while meeting the flame retardant performance requirements of 1.5 mm V-0. The main manifestations are that dripping occurs during the vertical combustion test or perforation occurs during the needle flame combustion and fails. Existing commercially available halogen-free flame retardant PC materials usually exhibit one of these two failure forms. The contradiction between the two test requirements is that in order to ensure the 1.5 mm V-0 vertical combustion rating, it is usually necessary to increase the content of the anti-dripping agent to avoid dripping combustion during the combustion process and cause failure. However, during the needle flame combustion process, too high a content of the anti-dripping agent will cause the melt strength of the material to decrease after heating, and the anti-dripping agent will shrink. When shrinking, it will pull and break the melt, resulting in cracking of the workpiece and failure.

[0005] Therefore, in order to obtain high rigidity and toughness, meet the requirements of 1.5 mm V-0 flame retardancy, and the REACH environmental protection control requirements of the GB4943.1-2022 needle flame test standard, it is necessary to further optimize and modify the polycarbonate material. Summary of the Invention

[0006] In view of the problems of poor flame retardancy and needle flame test performance of the polycarbonate materials involved in the above-mentioned prior art, the present invention provides a polycarbonate composition, a preparation method thereof and an application.

[0007] To achieve the above object, the specific technical solutions include the following:

[0008] A polycarbonate composition, comprising the following components in parts by weight: 100 parts of polycarbonate, 0.01 - 0.1 part of sulfonate flame retardant, 0.1 - 0.8 part of anti-dripping agent, 0.01 - 0.1 part of alkaline aqueous solution;

[0009] The melt index of the polycarbonate is 5 - 28 g / 10 min, and the melt index is tested according to the ISO 1133 - 12011 standard, and the test conditions are 300 °C and 1.2 kg.

[0010] The flame retardant mechanism of the sulfonate flame retardant is to promote the degradation of PC and the Fries rearrangement, thereby leading to the formation of a carbon layer to block the entry of heat and oxygen and block the combustion process. In the present invention, a certain amount of alkaline aqueous solution is added to the polycarbonate composition. During the extrusion granulation process, a certain amount of heat is provided, which will cause a certain degree of degradation of PC under the action of alkalinity and moisture, which is equivalent to advancing the time of PC degradation, making the polycarbonate degrade to a certain extent, which can advance the Fries process, making the carbon layer easier to form and denser during the combustion process, improving the degree of blocking combustion, so that the polycarbonate composition can more easily pass the vertical combustion test, and during the needle flame combustion process, due to the formation of a denser carbon layer, the shrinkage of the anti-dripping agent will not cause melt fracture, and the component will not fail due to cracking during combustion.

[0011] The alkaline aqueous solution should also be appropriate. Because if the addition amount is too small, it will not affect the whole composition. If the addition amount is too large, the degradation degree of the polycarbonate will be too large, and the strength of the polycarbonate will decrease significantly.

[0012] The polycarbonate composition of the present invention may further include other additives. However, the mass percentage content of polycarbonate in the polycarbonate composition is preferably greater than 80%, 90% or 95%.

[0013] As a preferred embodiment of the present invention, the pH value of the alkaline aqueous solution is 8 - 14.

[0014] As a further preferred embodiment of the present invention, the pH value of the alkaline aqueous solution is 10 - 13.

[0015] The pH value of the alkaline aqueous solution can be 8.1, 8.3, 8.5, 8.7, 8.9, 9.1, 9.3, 9.5, 9.7, 9.9, 10.1, 10.3, 10.5, 10.7, 10.9, 11.1, 11.3, 11.5, 11.7, 11.9, 12.1, 12.3, 12.5, 12.7, 12.9, 13.1, 13.3, 13.5, 13.7, 13.9, etc., as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0016] The parts by weight of the alkaline aqueous solution can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0017] As a preferred embodiment of the present invention, the melt index of the polycarbonate is 6 - 20 g / 10 min, more preferably 10 - 19 g / 10 min, and the melt index is tested according to the ISO 1133 - 1 2011 standard under the test conditions of 300 °C and 1.2 kg.

[0018] As a preferred embodiment of the present invention, the anti - dripping agent accounts for 0.2 - 0.4% of the mass of the polycarbonate.

[0019] As a preferred embodiment of the present invention, the base in the alkaline aqueous solution includes at least one of alkali metal hydroxides, alkaline earth metal hydroxides, ammonia water, and alkali metal carbonates.

[0020] As a further preferred embodiment of the present invention, the alkali metal hydroxide includes at least one of sodium hydroxide and potassium hydroxide.

[0021] As a preferred embodiment of the present invention, the weight content of the sulfonate flame retardant in the polycarbonate composition is not higher than 1000 ppm.

[0022] The parts by weight of the sulfonate flame retardant can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0023] The sulfonate flame retardant can include various organic sulfonate flame retardants, which include organic sulfonates having at least one carbon atom. The organic sulfonate can be an alkali metal salt, such as sodium salt, potassium salt, lithium salt or cesium salt, or an alkaline earth metal salt, such as magnesium salt, calcium salt, strontium salt or barium salt, or can also be a salt of a metal element such as iron, tin or zinc, an ammonium salt or an organic alkylamine salt.

[0024] The organic group of the organic sulfonate can be substituted by a halogen atom (such as fluorine, chlorine or bromine). Among the halogen atoms, fluorine is the most preferred, and alkali metal salts or alkaline earth metal salts of perfluoroalkyl sulfonic acids represented by the general formula (CnF2n+1SO3)mM are common, where n represents a natural number from 1 to 10, M represents lithium, sodium, potassium and cesium, or magnesium, calcium, strontium and barium, and m is equal to the valence 1 or 2 of M. More specifically, perfluoromethanesulfonate, perfluoroethanesulfonate, perfluoropropanesulfonate, perfluorobutanesulfonate, perfluorohexanesulfonate, perfluoroheptanesulfonate, perfluorooctanesulfonate, etc. can be used. Among them, potassium perfluorobutanesulfonate is particularly suitable.

[0025] In addition, at least one of alkyl sulfonate, benzenesulfonate, alkylbenzenesulfonate, diphenylsulfonate, naphthalenesulfonate, 2,5-dichlorobenzenesulfonate, 2,4,5-trichlorobenzenesulfonate, diphenyl sulfone-3-sulfonate, diphenyl sulfone-3,3'-disulfonate, naphthalene trisulfonate and their fluorine substituents can be specifically used.

[0026] As a preferred embodiment of the present invention, the anti-dripping agent includes polytetrafluoroethylene (PTFE).

[0027] The parts by weight of the anti-dripping agent can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc., and specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0028] A method for preparing the polycarbonate composition described above includes the following steps:

[0029] Blend the raw material components except the alkaline aqueous solution to obtain a premix; then carry out melt blending, extrusion and granulation on the premix and the alkaline aqueous solution in sequence to obtain the polycarbonate composition.

[0030] As a preferred embodiment of the present invention, the temperature of the melt blending is 250-280 °C.

[0031] As a preferred embodiment of the present invention, the melt blending is carried out under a vacuum degree of -0.07 to 0.08 MPa.

[0032] Another object of the present invention is to provide the application of the polycarbonate composition in the outer shell parts of audio and communication products. In the polycarbonate composition containing a sulfonate flame retardant and a dripping inhibitor, a certain amount of alkaline aqueous solution is added to comprehensively achieve that the polycarbonate composition has excellent vertical burning and needle flame burning properties, good mechanical strength, meets environmental protection requirements, and is particularly suitable for flame-retardant plastic products in electronic appliances, such as the outer shell parts of audio and communication products.

[0033] Compared with the prior art, the present invention has the following beneficial effects: In the polycarbonate composition containing a sulfonate and a dripping inhibitor, a certain amount of alkaline aqueous solution is added to overall achieve that the polycarbonate composition has excellent vertical burning and needle flame burning properties, good mechanical strength, meets environmental protection requirements, and is particularly suitable for products in industries such as audio and communication. Detailed implementation manners

[0034] To better illustrate the object, technical solution and advantages of the present invention, the present invention will be further described below through specific examples. The test methods used in the examples and / or comparative examples are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0035] Information of some raw materials:

[0036] Polycarbonate No. 1: PC 7030R, melt index 4.2 g / 10 min, Mitsubishi of Japan;

[0037] Polycarbonate No. 2: PC WY-106BR, melt index 6 g / 10 min, Lihua Yi;

[0038] Polycarbonate No. 3: PC 2100, melt index 10 g / 10 min, Wanhua Chemical;

[0039] Polycarbonate No. 4: PC 2220, melt index 19 g / 10 min, Wanhua Chemical;

[0040] Polycarbonate No. 5: PC H-3000F, melt index 30 g / 10 min, Mitsubishi of Japan;

[0041] Sulfonate flame retardant: Potassium perfluorobutanesulfonate SC4, Jiangxi Guohua Chemical Industry;

[0042] Dripping inhibitor: Polytetrafluoroethylene AD541, Changshu Zhenfu New Materials Co., Ltd.;

[0043] Talc powder: TY90-13C, average particle size D50 is 8.0 microns, pH value is 8.7, Dongguan Sanzhi New Materials Co., Ltd.

[0044] Examples 1-12 and Comparative Examples 1-7

[0045] Examples 1-12 and Comparative Examples 1-7 A method for preparing a polycarbonate composition, comprising the following steps:

[0046] (1) Preparation of alkaline aqueous solution

[0047] Weigh a certain amount of sodium hydroxide powder and put it into a glass beaker, pour in 100 mL of deionized water, stir magnetically at room temperature for 10 min, and prepare an alkaline aqueous solution with the corresponding concentration in the above-mentioned manner;

[0048] (2) Weigh each raw material component except the sodium hydroxide aqueous solution according to the formula in Table 1-2, and mix the components in a high-speed mixer for 10 minutes to obtain a premix;

[0049] (3) Put the premix into a twin-screw extruder through a feeder, the screw speed is 400-600 revolutions per minute, the processing temperature is 250-280 °C, double vacuum is adopted, the vacuum degree is -0.07 to 0.08 MPa, and the sodium hydroxide aqueous solution is injected into the screw at the fourth position of the screw by a liquid pump according to the weight parts in Table 1-2. After melting, dispersing, and blending, and then through extrusion, drawing, cooling, drying, and pelletizing, the polycarbonate composition is obtained.

[0050] Performance test:

[0051] (1) Needle flame combustion test: Take the polycarbonate composition sample particles of Examples 1-12 and Comparative Examples 1-7, dry them at 120 °C for 4 h, and then injection mold them into a square box with a thickness of 2.0 mm at 280 °C. According to the GB4943.1-2022 needle flame test standard, select the weakest corner position as the flame application position. The height of the needle flame is 12 mm. After burning at the flame application position for 60 s, move it away. If the sample part does not burn through after the flame of the part goes out, it indicates that the sample part can pass the test.

[0052] (2) Izod notched impact strength: Prepare standard samples according to the Type A notch of ISO 180 2019 standard. Take 5 standard specimens, use a 2.75 J pendulum to test the energy required to break the specimen, and calculate the Izod notched impact strength value of the specimen.

[0053] (3) Melt index (melt flow rate): Take the polycarbonate composition samples of Examples 1-12 and Comparative Examples 1-7 to prepare standard samples according to the ISO 1133-1 2011 standard, and test at 300 °C and a load of 1.2 kg. The melt index of the composition after pelletizing can be compared with the initial selected PC melt index, and it can also reflect the degree of PC degradation during the pelletizing process.

[0054] (4) 1.5 mm Vertical Combustion: Sample strips of the polycarbonate compositions of Examples 1-12 and Comparative Examples 1-7 were prepared according to the UL 94 2016 standard, and the sample strips were tested. The t1 and t2 times involved in the test process were counted for the determination of the flame retardancy rating.

[0055] Table 1 (parts by weight)

[0056]

[0057]

[0058] Table 2 (parts by weight)

[0059]

[0060] As can be seen from Examples 1-12, the polycarbonate composition has excellent vertical combustion and needle flame combustion properties, and at the same time has high strength, with a notched impact strength greater than 600 J / m.

[0061] As can be seen from Example 1 and Comparative Examples 3-4, adding a certain amount of alkaline solution can significantly improve the needle flame combustion performance of the composition; and when added in the form of solid base, there will be problems such as less addition amount, difficult dispersion and accurate control, uneven contact with polycarbonate, and little improvement in the needle flame combustion performance of the overall composition. In the present invention, adding in the form of alkaline solution not only facilitates its dispersion, making the contact between the base and the premix more uniform, but also the presence of water therein has a certain degradation effect on PC, assisting in controlling the degradation degree of PC.

[0062] As can be seen from Example 1, Examples 4-5 and Comparative Examples 5-6, the addition amount of the anti-dripping agent has an obvious influence on the impact resistance, needle flame combustion performance and vertical combustion performance of the composition. If the addition amount is too low, the vertical combustion performance of the composition is poor; if the addition amount is too high, the anti-dripping agent shrinks severely during combustion, resulting in poor needle flame combustion performance. Preferably, the anti-dripping agent accounts for 0.2-0.4% of the mass of the polycarbonate.

[0063] As can be seen from Example 1 and Examples 9-12, when the addition amount of the flame retardant is the same, the higher the pH, the greater the degradation degree during the blending and pelletizing process of the composition, the more the melt flow rate of the composition increases, and the lower the mechanical properties. However, the increase in the degradation degree is beneficial to the improvement of the flame retardancy performance. Therefore, the present invention realizes a polycarbonate composition with good comprehensive performance of both flame retardancy and mechanics by balancing the flame retardancy and mechanical properties.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polycarbonate composition, characterized in that, It comprises components in the following parts by weight: 100 parts of polycarbonate, 0.01 - 0.1 part of sulfonate flame retardant, 0.1 - 0.8 part of anti-dripping agent, and 0.01 - 0.1 part of alkaline aqueous solution; The melt index of the polycarbonate is 5 - 28 g / 10 min, and the melt index is tested according to the ISO 1133 - 12011 standard under the test conditions of 300 °C and 1.2 kg; The alkali in the alkaline aqueous solution includes at least one of alkali metal hydroxides, alkaline earth metal hydroxides, ammonia water, and alkali metal carbonates.

2. The polycarbonate composition according to claim 1, characterized in that, The pH value of the alkaline aqueous solution is 8 - 14.

3. The polycarbonate composition according to claim 1, characterized in that, The melt index of the polycarbonate is 10 - 19 g / 10 min.

4. The polycarbonate composition according to claim 1, characterized in that, The anti-dripping agent accounts for 0.2 - 0.4% of the mass of the polycarbonate.

5. The polycarbonate composition according to claim 1, wherein The alkaline solution accounts for 0.02 - 0.05% of the mass of the polycarbonate.

6. The polycarbonate composition according to claim 1, characterized in that, The sulfonate flame retardant includes at least one of alkyl sulfonates, benzene sulfonates, alkyl benzene sulfonates, diphenyl sulfonates, naphthalene sulfonates, 2,5-dichlorobenzene sulfonates, 2,4,5-trichlorobenzene sulfonates, diphenyl sulfone-3-sulfonates, diphenyl sulfone-3,3'-disulfonates, naphthalene trisulfonates, and their fluorine substitutes.

7. The polycarbonate composition according to claim 1, characterized in that, The anti-dripping agent includes polytetrafluoroethylene.

8. A method for preparing the polycarbonate composition according to any one of claims 1 to 7, characterized in that, It includes the following steps: Blend the raw material components except the alkaline aqueous solution to obtain a premix; then melt blend, extrude, and pelletize the premix and the alkaline aqueous solution in sequence to obtain the polycarbonate composition.

9. Application of the polycarbonate composition according to any one of claims 1 to 7 in the outer shell parts of audio and communication products.

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