Burn-through-resistant PC material meeting needle flame S.2 flame retardant requirement and preparation method thereof

Abstract

The invention discloses a burnthrough-resistant PC material meeting needle flame S.2 flame retardant requirements and a preparation method thereof. According to the total weight of 100 parts, the material composition comprises the following raw materials: 80-93.95 parts of PC resin; 0.05 to 1 part of a flame retardant; 5 to 15 parts of a flame retardant synergist; 0.5-2 parts of a functional filler; and 0.5-2 parts of other auxiliary agents. The prepared flame-retardant PC material can realize flame retardance V-0 (1.5 mm) and S.2 (1.5 mm) needle flame test, and meets the safety requirements of new national standard GB 4943.1-2022 on audio and video, information technology and communication technology equipment.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification, specifically to a PC material that is resistant to burn-through and meets the requirements of needle flame S.2 flame retardancy, and its preparation method. Background Technology

[0002] PC, as an engineering plastic with excellent comprehensive performance, has outstanding impact toughness, good dimensional stability and electrical insulation, and is widely used in home appliance housings, 3C consumer electronics, automobiles and other fields.

[0003] As electronic products increasingly trend towards thinner designs, the growing trend towards ultra-thin designs presents new challenges to safety requirements. The GB 4943.1-2022 standard has added the S.2 needle flame test requirement to its flame retardant performance testing, covering information technology equipment, audio equipment, and video equipment. Currently, conventional flame-retardant V0 PC materials on the market face challenges in the S.2 needle flame test, finding it difficult to pass the test for thicknesses below 3.0 mm. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a PC material that is resistant to burn-through and meets the S.2 flame retardant requirements, along with its preparation method. The prepared flame-retardant PC material can achieve a flame retardant V-0 (1.5mm) and can also pass the S.2 (1.5mm) needle flame test, meeting the safety requirements of the new national standard GB 4943.1-2022 for audio-visual, information technology, and communication technology equipment.

[0005] The specific technical solution is as follows: A burn-through resistant PC material that meets the needle flame S.2 flame retardant requirements, based on a total weight of 100 parts, comprises the following raw material components: 80~93.95 parts of PC resin; Flame retardant 0.05~1 part; 5-15 parts of flame retardant synergist; 0.5 to 2 parts of functional filler; Other additives: 0.5-2 parts.

[0006] Preferably, the PC resin has a melt flow rate of 10~20 g / 10min and a weight-average molecular weight of 20,000~40,000 under the conditions of 300°C and 1.2 kg.

[0007] Preferably, the flame retardant is a halogen-free sulfonate flame retardant, which may be selected from one or more of potassium perfluorobutyl sulfonate, potassium benzenesulfonylbenzenesulfonate, and sodium benzenesulfonylbenzenesulfonate.

[0008] Preferably, the flame retardant synergist is a mixture of polymethylphenylsiloxanes.

[0009] The structure of the polymethylphenylsiloxane mixture is shown in formula (I): ; n is a positive integer from 100 to 500. If the value of n is too small, the flame retardant and anti-dripping effect will not be good; m is a positive integer from 0 to 7.

[0010] Preferably, the functional filler is one or both of A and B.

[0011] Functional filler A is silica microspheres with a particle size D50 of 2~100μm, preferably 5~30μm. The smaller the particle size, the better the overall performance.

[0012] Functional filler B is mica powder with an average particle size of 20~100μm. If the particle size is too small (1.5mm), it will fail the needle flame test; if the particle size is too large, it will affect other mechanical properties.

[0013] Preferably, the other additives include antioxidants and lubricants, which are commercially available antioxidants and lubricants that can be used in PC materials.

[0014] The antioxidant is preferably a compound composed of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1.

[0015] The lubricant is preferably selected from at least one of calcium stearate, ethylene bis-stearamide, and silicone powder.

[0016] This invention also discloses a method for preparing a PC material that is resistant to burn-through and meets the requirements for needle flame S.2 retardancy, characterized by comprising the following steps: 1) Mix the above PC resin and additives together using a high-speed mixer until homogeneous; 2) The mixture is fed into the main feed port of a twin-screw extruder, and after extrusion, granulation and drying, a PC material that is resistant to burn-through and meets the needle flame S.2 flame retardant requirements is obtained. The twin-screw extruder has a length-to-diameter ratio of 40:1, and the temperature of each temperature zone from feeding to extrusion discharge is set as follows: Zone 1: 240~260℃, Zones 2 to 9: 280~260℃, and Die: 280~270℃.

[0017] The flame-retardant PC material prepared by this invention can be used in information technology equipment, audio equipment, and video equipment, etc.

[0018] Compared with the prior art, the present invention has the following advantages: This invention provides a PC material that is burn-through resistant and meets the S.2 flame retardant requirements, along with its preparation method. A flame-retardant composite system composed of a sulfonate-based halogen-free flame retardant and polymethylsiloxane achieves thin-wall flame retardancy in the PC material. Compared to traditional flame-retardant methods where adding anti-dripping agents significantly reduces the S.2 flame performance, this invention effectively improves the flame-retardant PC material's flame performance through the composite polymethylsiloxane. Furthermore, the S.2 flame performance is further enhanced by the composite functional filler. Through the synergistic effect of these methods, the resulting flame-retardant PC material achieves a flame retardant V-0 (1.5mm) rating and also meets the S.2 (1.5mm) flame retardant test requirements, satisfying the safety requirements of the new national standard GB 4943.1-2022 for audio-visual, information technology, and communication technology equipment. Detailed Implementation

[0019] In various embodiments of the present invention, the following brands of raw materials are specifically selected: The PC resin used is Luxi Chemical's 1609T grade, with a material MI of 9g / 10min (300℃ / 1.2kg).

[0020] The halogen-free flame retardant used is sulfonate flame retardant SC4 (Jiangxi Guohua) or F535 (SLOSS, USA).

[0021] The polymethylphenylsiloxane flame retardant synergist is a mixture of Dow Corning 40-001 and Shenzhen Jipeng Silicon Fluorine Materials methylphenyl silicone resin 3047, with a ratio of 40-001:3047=2:1.

[0022] Functional filler A is silica microspheres with a particle size D50 of 2~100μm, preferably 5~30μm. Specifically, Guangzhou Aonuoshi Chemical HM-SS10 (7-13μm) and QS-M90 (60~80μm) are selected.

[0023] Functional filler B is mica powder with an average particle size of 20~100μm; specifically, GM-5 mica powder (37μm) and GM-6 mica powder (15μm) from Gree Mining are selected.

[0024] The antioxidants are selected from commercially available antioxidants 1010 and 168, compounded in a weight ratio of 1:1.

[0025] The lubricant is selected from commercially available calcium stearate.

[0026] All other additives used in the examples and comparative examples are commercially available.

[0027] The test methods for the properties of the composite PC materials obtained in each embodiment and comparative example are as follows: Physical and mechanical properties: Tensile properties were tested according to GB / T1040.2-2006 standard, with a tensile rate of 10 mm / min; flexural properties were tested according to GB / T9341-2008 standard, with a flexural deformation rate of 2 mm / min; notched impact properties were tested according to GB / T 1043.1-2008 standard; melt flow rate was tested according to GB / T3682-2000, with test conditions of 300℃*1.2 kg; flame retardant vertical burning test was tested according to GB / T 2408-2008 standard; needle flame S.2 was tested according to Appendix S.2 of GB 4943.1-2022 and GB / T5169.5-2020 method.

[0028] The present invention will be specifically described below through embodiments, but the technical scope of the present invention is not limited to these embodiments. In the present invention, unless otherwise specified, all parts refer to parts by weight.

[0029] Examples 1-6 relate to a PC material that is resistant to burn-through and meets the flame retardant requirements of needle flame S.2. The content of each component of the modified PC material is shown in Table 1.

[0030] The preparation methods of Comparative Examples 1 to 3 are the same as those of the Examples, and the components and proportions of each raw material are also shown in Table 1 below.

[0031] Material Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 PC 87.9 82.9 87.9 87.9 82.9 87.9 97.9 97.4 88.9 87.9 78.9 Flame retardant SC4 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Flame retardant synergist 10 15 10 10 15 10 0 0 10 0 20 Functional packing material A (HM-SS10) 1 1 0 0 0 1 1 0 1 1 Functional packing material A (QS-M90) 1 Functional filler B (GM-5 mica powder) 1 1 Functional filler B (GM-6 mica powder) 1 antioxidants 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 lubricant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 PTFE anti-dripping agent 0 0 0 0 0 0 0 0.5 0 silicone oil 10 *Antioxidant: 1010 / 168=1 / 1; Silicone oil is methylphenyl silicone oil with an n value < 50.

[0032] The preparation methods of Examples 1-6 are as follows: The above-mentioned PC resin and additives are mixed evenly in a high-speed mixer; then the mixture is fed into the main feed port of a twin-screw extruder, and after extrusion, granulation and drying, a PC material that is resistant to burn-through and meets the needle flame S.2 flame retardant requirements is obtained. The twin-screw extruder has a length-to-diameter ratio of 40:1, and the temperature of each temperature zone from feeding to extrusion discharge is set as follows: Zone 1: 240~260℃, Zones 2 to 9: 280~260℃, and Die: 280~270℃.

[0033] The performance of the products prepared in each embodiment and comparative example is shown in Table 2 below.

[0034] Material properties Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Tensile strength MPa 57.2 55.4 56.1 58.6 55.9 53.1 61.4 60.7 57.6 58.6 52.1 Flexural strength MPa 92.9 89.4 90.2 94.1 91.1 92.8 98.7 97.4 92.1 94.5 84.6 Flexural modulus MPa 2315 2187 2388 2421 2269 2300 2531 2498 2342 2352 2148 <![CDATA[Notched impact strength of simply supported beam KJ / m 2 > 56 65 53 25 32 23 48 57 61 52 71 Vertical burning (1.5mm) V-0 V-0 V-0 V-0 V-0 V-0 V-2 V-0 V-0 V-2 V-0 Needle flame S.2 (2.0mm) Okay Okay Okay Okay Okay Okay Okay NG Okay OK NG Needle flame S.2 (1.5mm) Okay Okay Okay Okay Okay NG NG NG NG NG NG The needle flame S.2 test OK means the test has passed, and NG means the test has failed.

[0035] As can be seen from the table above, this invention achieves thin-wall flame retardancy in PC materials through a flame-retardant compound system composed of sulfonate-based halogen-free flame retardants and polymethylsiloxane. Performance data from Examples 1-6 show that the modified PC material of this invention simultaneously achieves flame retardancy in both V-0 (1.5mm) and S.2 (1.5mm) needle flame tests. Comparing Examples 1-6, the two functional fillers have a certain impact on the impact performance of the PC material, with functional filler B having a greater impact on the notched impact performance of PC.

[0036] Comparing Example 1 and Comparative Examples 1-2, Comparative Example 1, by adding only sulfonate flame retardants, could not solve the problem of PC dripping during combustion; Comparative Example 2, by adding anti-dripping agents using traditional flame retardant methods, could achieve flame retardancy V-0 (1.5mm), but it would significantly reduce the S.2 needle flame performance of the material; the present invention, through a flame retardant compound system composed of sulfonate halogen-free flame retardants and polymethylsiloxane, solved the flame retardant dripping problem of PC materials without anti-dripping agents, ensuring that the PC material achieved flame retardancy V-0 (1.5mm) performance. Comparing Examples 1 / 4 and Comparative Example 3, it can be seen that functional fillers A and B can further improve the S.2 needle flame performance of PC materials, increasing the S.2 needle flame performance of PC from 2.0mm to 1.5mm. Comparative Example 4, using silicone oil with a smaller molecular weight, showed a significantly worse flame retardant synergistic effect compared to Example 1, failing to achieve a good anti-dripping effect, and the flame retardancy could only reach V-2 / 1.5mm. Comparative Example 5 showed that increasing the content of silicon-based flame retardant synergist still achieved V-0 / 1.5mm in vertical burning performance, but its needle flame S.2 performance decreased significantly. This indicates that silicon-based flame retardant synergist has a negative impact on the needle flame performance of PC materials.

[0037] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. The present invention is not limited to the embodiments described herein. Any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A PC material that is resistant to burn-through and meets the S.2 flame retardant requirements for needle flame, characterized in that, Based on a total weight of 100 portions, the raw material composition includes: 80~93.95 parts of PC resin; Flame retardant 0.05~1 part; 5-15 parts of flame retardant synergist; 0.5 to 2 parts of functional filler; Other additives: 0.5-2 parts; The functional filler is one or both of A and B; Functional filler A is silica microspheres with a particle size D50 of 2~100μm; Functional filler B is mica powder with an average particle size of 20~100μm.

2. The PC material according to claim 1, which is resistant to burn-through and meets the needle flame S.2 flame retardant requirements, is characterized in that... The PC resin preferably has a melt flow rate of 10~20 g / 10 min at 300℃ and 1.2 Kg, and a weight-average molecular weight of 20,000~40,000.

3. The PC material according to claim 1, which is resistant to burn-through and meets the needle flame S.2 flame retardant requirements, is characterized in that... The flame retardant is a halogen-free sulfonate flame retardant, which may be selected from one or more of potassium perfluorobutyl sulfonate, potassium benzenesulfonylbenzenesulfonate, and sodium benzenesulfonylbenzenesulfonate.

4. The PC material according to claim 1, which is resistant to burn-through and meets the flame retardant requirement of needle flame S.2, is characterized in that, The flame retardant synergist is a mixture of polymethylphenylsiloxanes; The structure of the polymethylphenylsiloxane mixture is shown in formula (I): （I） n is a positive integer from 100 to 500, and m is a positive integer from 0 to 7.

5. The PC material according to claim 1, which is resistant to burn-through and meets the flame retardant requirement of needle flame S.2, is characterized in that, The other additives include antioxidants and lubricants.

6. The PC material according to claim 5, which is resistant to burn-through and meets the flame retardant requirement of needle flame S.2, is characterized in that, The antioxidant is selected from a compound composed of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:

1.

7. The PC material according to claim 5, which is resistant to burn-through and meets the needle flame S.2 flame retardant requirements, is characterized in that, The lubricant is selected from at least one of calcium stearate, ethylene bis-stearamide, and silicone powder.

8. A method for preparing a PC material that is resistant to burn-through and meets the flame retardant requirements of needle flame S.2 according to any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Mix the above PC resin and additives together using a high-speed mixer until homogeneous; 2) The mixture is fed into the main feed port of a twin-screw extruder, and after extrusion, granulation and drying, a PC material that is resistant to burn-through and meets the needle flame S.2 flame retardant requirements is obtained. The twin-screw extruder has a length-to-diameter ratio of 40:1, and the temperature of each temperature zone from feeding to extrusion discharge is set as follows: Zone 1: 240~260℃, Zones 2 to 9: 280~260℃, and Die: 280~270℃.

9. A PC material according to any one of claims 1 to 7 that is resistant to burn-through and meets the needle flame S.2 flame retardant requirement is used in information technology equipment, audio equipment and video equipment.

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