High-temperature and high-humidity aging resistant halogen-free flame-retardant PC-ABS alloy material and preparation method thereof

Abstract

The invention provides a high temperature and high humidity aging resistant halogen-free flame retardant PC-ABS alloy material, which is characterized by comprising the following raw materials by weight: 70-80 parts of PC, 8-15 parts of ABS, 3-5 parts of ABS-g-MAH, 5-10 parts of a compound flame retardant, 1-3 parts of a silicate heat resistant agent, 1-3 parts of graphene, and 0.5-1 part of an antioxidant. The compound flame retardant is a combination of a sulfonate flame retardant, modified zinc borate and resorcinol bis (diphenyl phosphate) (RDP), and by optimizing a flame-retardant system and adding a silicate heat-resistant agent and graphene, not only is flame-retardant performance reduction caused by hydrolysis of the flame retardant avoided, but also the heat resistance of the material is improved, the interface bonding force is enhanced, and the service life of the material is prolonged. And the mechanical property of the alloy is improved.

Description

Technical Field

[0001] This invention relates to the field of polymer alloy materials technology, specifically to halogen-free flame-retardant PC-ABS alloy materials resistant to high temperature and high humidity aging and their preparation methods. Background Technology

[0002] PC / ABS alloy, a resin-based composite material obtained by blending polycarbonate (PC) and acrylonitrile-butadiene-styrene copolymer (ABS), combines the high strength, high heat resistance, and excellent light transmittance of PC with the good processing fluidity of ABS. In recent years, thanks to its balance of mechanical properties and processability, PC / ABS alloy has been widely used in outdoor applications such as charging pile housings for new energy vehicles and 5G base station housings.

[0003] Although PC / ABS has the advantages of both plastics, it also has some shortcomings. Among them, the flammability of ABS leads to poor flame retardancy. In order to improve the flame retardancy and meet the needs of industry applications, phosphorus-based flame retardants are usually added to PC / ABS alloys. At present, PC / ABS alloys are increasingly used in high temperature and high humidity environments (such as 85℃ / 85%RH). Under such conditions, existing materials have the following shortcomings: (1) Traditional phosphorus-based flame retardants (such as TPP and RDP) are easy to hydrolyze to generate phosphoric acid, which leads to a decrease in flame retardancy efficiency; (2) ABS resin has poor hydrolysis resistance, and its impact strength decreases significantly after damp heat aging, and the surface is prone to cracking; (3) The PC / ABS phase interface swells and separates due to moisture penetration, which leads to material embrittlement and a decrease in tensile strength. Summary of the Invention

[0004] To address the issues of decreased flame retardant efficiency, deteriorated mechanical properties, and poor interfacial stability in PC / ABS alloys after aging under high temperature and humidity conditions, this invention provides a halogen-free flame-retardant PC / ABS alloy material with excellent resistance to high temperature and humidity aging and its preparation method. By optimizing the flame retardant system and adding silicate heat-resistant agents and graphene, not only is the decline in flame retardant performance caused by the hydrolysis of flame retardants avoided, but the heat resistance of the material is also improved, the interfacial bonding force is enhanced, and the mechanical properties of the alloy are improved.

[0005] The specific technical solution adopted in this invention is as follows: A halogen-free flame-retardant PC / ABS alloy material with excellent resistance to high temperature and high humidity aging, comprising, by weight, the following raw materials: 70-80 parts PC, 8-15 parts ABS, 3-5 parts ABS-g-MAH, 5-10 parts compound flame retardant, 1-3 parts silicate heat resistant agent, 1-3 parts graphene, and 0.5-1 parts antioxidant; wherein the compound flame retardant is a combination of sulfonate flame retardant, modified zinc borate, and resorcinol bis(diphenyl phosphate) (RDP).

[0006] Furthermore, the sulfonate flame retardant is potassium 3-benzenesulfonylbenzenesulfonate.

[0007] Furthermore, the modified zinc borate is zinc borate modified with sodium stearate.

[0008] Furthermore, the mass ratio of the sulfonate flame retardant, modified zinc borate, and resorcinol bis(diphenyl phosphate) (RDP) is 0.5-1:3-6.5:1.5-2.5.

[0009] Furthermore, the preparation method of the compound flame retardant is to mix the three components in a high-speed mixer at 1000-3000 rpm in the required proportions until homogeneous.

[0010] Furthermore, the silicate heat-resistant agent is one or more of organically modified montmorillonite, mica, and kaolin.

[0011] Furthermore, the graphene is one or more of single-layer graphene, double-layer graphene, or few-layer graphene.

[0012] This invention also provides a method for preparing a halogen-free flame-retardant PC / ABS alloy material with excellent resistance to high-temperature and high-humidity aging:

[0013] (1) PC, ABS, ABS-g-MAH, compound flame retardant, silicate heat resistant agent, graphene and antioxidant are added to a high-speed mixer in sequence for mixing and stirring for 3-10 minutes.

[0014] (2) Add the mixture to a twin-screw extruder, and extrude, granulate and air dry to obtain the halogen-free flame-retardant PC / ABS alloy material of the present invention with excellent resistance to high temperature and high humidity aging; the screw speed of the twin-screw extruder is 40-60 r / min, and the temperatures of the feeding section, mixing section, compression metering section, die head and die head are 200-210℃, 220-250℃, 240-260℃, 225-255℃ and 210-220℃ respectively.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects.

[0016] (1) This invention employs a compound flame retardant consisting of sulfonate flame retardants, modified zinc borate, and resorcinol bis(diphenyl phosphate) (RDP). The sulfonate flame retardant decomposes at high temperatures to produce acidic substances, which induce cross-linking and aromatization reactions in polycarbonate (PC) molecular chains, promoting the formation of a dense char layer and achieving high-efficiency flame retardancy. Resorcinol bis(diphenyl phosphate) mainly functions in ABS through a condensation mechanism. Its thermal decomposition products promote the dehydration and char formation of the styrene-acrylonitrile phase, inhibiting the release of combustible gases, thereby reducing the heat release rate and smoke generation. Modified zinc borate coats the surface of resorcinol bis(diphenyl phosphate), forming a physical barrier and delaying the hydrolysis reaction of the phosphate groups, thereby improving its performance in humid and hot environments.

[0017] (2) The layered silicate soil in the silicate heat resistant agent used in this invention extends the pyrolysis path, significantly reduces the peak heat release rate, improves the heat resistance of the material, and meets the long-term use requirements at high temperatures of 80-90℃.

[0018] (3) The graphene of the present invention has a better affinity with ABS-g-MAH than PC and ABS. Therefore, it will migrate to the interface of PC and ABS during the melting and mixing process, thereby improving the interfacial bonding force. At the same time, the excellent mechanical properties of graphene can also improve the mechanical properties of the material. Detailed Implementation

[0019] The following embodiments are merely examples covered by the present invention and do not constitute any limitation on the scope of implementation.

[0020] In the following embodiments and comparative examples, the raw materials use the following components:

[0021] PC: Grade S2001R, melt flow rate (MFR) = 7.5-10.5 g / 10 min (1.2 kg / 300 °C), supplied by Mitsubishi Plastics Co., Ltd. (Japan).

[0022] ABS: Grade PA757, melt flow rate (MFR) = 1.8g / 10min (5kg / 200℃), supplied by Chi Mei Corporation, Taiwan, China.

[0023] ABS-g-MAH: Grade KT-3, melt flow rate (MFR) = 1.0-4.0 g / 10 min (5 kg / 200℃), supplied by Shenyang Ketong Plastics Co., Ltd.

[0024] Sulfonate flame retardant: Potassium 3-benzenesulfonylbenzenesulfonate (KSS, Xinghengye).

[0025] Modified zinc borate: Zinc borate is obtained by surface treatment with sodium stearate. The zinc borate is supplied by Shandong Wuwei.

[0026] Resorcinol bis(diphenyl phosphate) (RDP): Hunan Fengen

[0027] Silicate heat resistant agent: Organic modified montmorillonite, DK1N, Zhejiang Fenghong Clay Chemical Co., Ltd.

[0028] Graphene: SE1430, Changzhou Sixth Element Materials Technology Co., Ltd.

[0029] Antioxidant: AO-60, Greenlink (Jining) Chemical Technology Co., Ltd.

[0030] Examples 1-5 and Comparative Examples 1-5:

[0031] Table 1. Components and proportions of Examples 1-5 and Comparative Examples 1-5

[0032]

[0033] The preparation method is as follows:

[0034] (1) The sulfonate flame retardant, modified zinc borate and resorcinol bis(diphenyl phosphate) (RDP) were mixed evenly in a high-speed mixer at 1500 rpm according to the proportion.

[0035] (2) Add PC, ABS, ABS-g-MAH, compound flame retardant, silicate heat resistant agent, graphene and antioxidant to a high-speed mixer in sequence according to the proportion, and mix at 1000 rpm for 5 minutes.

[0036] (3) The mixture is fed into a twin-screw extruder with a screw speed of 60 r / min. The temperatures of each zone are: 205℃ for the feeding section, 240℃ for the mixing section, 255℃ for the compression metering section, 240℃ for the die head, and 215℃ for the die head. The extruded strip is water-cooled, air-dried, and pelletized. The resulting pellets are dried at 50℃ for 4 hours and then injection molded into standard samples at 240-260℃.

[0037] To test the material's resistance to high temperature and humidity, the samples prepared in Examples 1-5 and Comparative Examples 1-5 were first treated at 85℃ / 85%RH for 500 hours. After the treatment, the performance of the samples was tested according to national experimental standards.

[0038] Tensile strength was tested according to GB / T 1040-2006 standard, with a tensile speed of 100 mm / min;

[0039] Bending strength was tested according to GB / T9341-2008 standard, with a bending speed of 2 mm / min;

[0040] The notched impact strength was tested according to GB / T1043-2008 standard, and the notched specimen width was 8 mm.

[0041] The heat distortion temperature was tested according to GB / T1634.2-2019 standard, and the test condition was 1.8MPa;

[0042] Flame retardancy rating, tested according to the method specified in UL-94.

[0043] The test results are shown in Table 2 below.

[0044] Table 2 Test results of Examples 1-5 and Comparative Examples 1-5

[0045]

[0046]

[0047] As shown in Table 2, the PC / ABS alloy materials obtained in Examples 1-5 have the lowest tensile strength of 52.5 MPa, the lowest flexural strength of 71.1 MPa, and the lowest notched impact strength of 41.8 kJ / m. 2 The lowest heat distortion temperature was 111℃, and the flame retardant rating was V-0. Compared with Example 2, Comparative Example 1 showed that the lack of sulfonate flame retardants led to a decrease in flame retardant efficiency, and the flame retardant rating dropped to V-1. Compared with Example 2, Comparative Example 2 lacked modified zinc borate, which made resorcinol bis(diphenyl phosphate) (RDP) easy to hydrolyze, resulting in flame retardant failure and decreased interfacial stability, and the flame retardant rating dropped to V-2. The heat distortion temperature and mechanical properties also decreased. Compared with Example 2, Comparative Example 3 lacked resorcinol bis(diphenyl phosphate) (RDP), resulting in insufficient smoke suppression of ABS, the flame retardant rating dropped to V-2, mechanical properties decreased, and the heat distortion temperature was slightly lower. Compared with Example 2, Comparative Example 4 lacked silicate heat resistant agents, and the heat resistance and mechanical properties decreased significantly. Compared with Example 2, Comparative Example 5 lacked graphene, the interfacial bonding force was weakened, and the mechanical properties and heat resistance decreased.

[0048] In summary, the PC / ABS alloy material prepared by this invention also possesses excellent mechanical properties, heat resistance, and flame retardancy under high temperature and high humidity environments, which can meet the application requirements under high humidity and high heat environments.

[0049] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A halogen-free flame-retardant PC-ABS alloy material resistant to high temperature and high humidity aging, characterized in that, By weight, the raw materials include: 70-80 parts PC, 8-15 parts ABS, 3-5 parts ABS-g-MAH, 5-10 parts compound flame retardant, 1-3 parts silicate heat resistant agent, 1-3 parts graphene, and 0.5-1 parts antioxidant; the compound flame retardant is a combination of sulfonate flame retardant, modified zinc borate, and resorcinol bis(diphenyl phosphate) (RDP).

2. The PC / ABS alloy material according to claim 1, characterized in that, The sulfonate flame retardant is potassium 3-benzenesulfonylbenzenesulfonate.

3. The PC / ABS alloy material according to claim 2, characterized in that, The modified zinc borate is zinc borate modified with sodium stearate.

4. The PC / ABS alloy material according to claim 3, characterized in that, The mass ratio of the sulfonate flame retardant, modified zinc borate, and resorcinol bis(diphenyl phosphate) (RDP) is 0.5-1:3-6.5:1.5-2.

5.

5. The PC / ABS alloy material according to claim 4, characterized in that, The preparation method of the compound flame retardant is to mix the three components in the required proportion in a high-speed mixer at 1000-3000 rpm until homogeneous.

6. The PC / ABS alloy material according to claim 1, characterized in that, The silicate heat-resistant agent is one or more of organically modified montmorillonite, mica, and kaolin.

7. The PC / ABS alloy material according to claim 1, characterized in that, The graphene is one or more of single-layer graphene, double-layer graphene, or few-layer graphene.

8. A method for preparing a halogen-free flame-retardant PC / ABS alloy material with excellent resistance to high temperature and high humidity aging as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) PC, ABS, ABS-g-MAH, compound flame retardant, silicate heat resistant agent, graphene and antioxidant are added to a high-speed mixer in sequence for mixing and stirring for 3-10 minutes. (2) Add the mixture to a twin-screw extruder, and extrude, granulate and air dry to obtain a halogen-free flame-retardant PC / ABS alloy material with excellent resistance to high temperature and high humidity aging.

9. The method for preparing PC / ABS alloy material according to claim 8, characterized in that, In step (2), the screw speed of the twin-screw extruder is 40-60 r / min.

10. The method for preparing the PC / ABS alloy material according to claim 9, characterized in that, In step (2), the temperatures of the feeding section, mixing section, compression metering section, die head and die head of the twin-screw extruder are 200-210℃, 220-250℃, 240-260℃, 230-255℃ and 210-220℃, respectively.

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