A PBT composition, its preparation method and application

Abstract

The present invention relates to a PBT composition, a preparation method and an application thereof. The components include: PBT resin, a halogen-free flame retardant, glass fiber, dimethyl silicone oil, a film-forming agent, and zirconium phosphate. After aging, the PBT composition of the present invention has a good retention rate of tensile strength. At the same time, the permanent deformation amount after the rubber sealing ring contacts the halogen-free flame retardant-reinforced PBT material is reduced, that is, the retention rate of the resilience performance is increased.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and particularly relates to a PBT composition and a preparation method and application thereof. Background Art

[0002] Silicone rubber is an important type of synthetic rubber. Its main molecular chain is -Si-O- structure, and its side chains are alkyl, vinyl, phenyl and other groups. Silicone rubber has higher stability than general rubber, and its excellent electrical insulation properties make it the preferred material for various protection and sealing of electronic and electrical equipment. Its main components include sealing rings and gaskets. Due to the requirements of combustion safety and regulations, more and more electronic and electrical products have put forward flame retardant requirements for the plastic materials used in them. In actual use, it is found that the elasticity of silicone rubber sealing rings decreases and even becomes brittle after long-term contact with halogen-free flame-retardant PBT material parts, resulting in sealing failure. Summary of the invention

[0003] In view of the defects of the prior art, the present invention provides a PBT composition and a preparation method and application thereof.

[0004] A PBT composition of the present invention comprises, by weight:

[0005]

[0006] The film-forming agent is one or more of epoxidized soybean oil, polyvinyl alcohol and dipentaerythritol.

[0007] Preferably, the halogen-free flame retardant is one or more of aluminum hypophosphite, aluminum diethylphosphinate, and melamine cyanurate.

[0008] Preferably, the film-forming agent is epoxy soybean oil and polyvinyl alcohol in a mass ratio of (4:1) to (2:3); or epoxy soybean oil and dipentaerythritol in a mass ratio of (4:1) to (2:3).

[0009] More preferably, the film-forming agent is epoxy soybean oil and polyvinyl alcohol in a mass ratio of (3:2) to (1:1); or epoxy soybean oil and dipentaerythritol in a mass ratio of (3:2) to (1:1).

[0010] Preferably, the auxiliary agent is one or more of an antioxidant and a lubricant.

[0011] Preferably, the antioxidant is one or more of hindered phenols and thioesters; and the lubricant is one or more of amide lubricants.

[0012] Preferably, by weight, the components include:

[0013]

[0014] A preparation method of the PBT composition of the present invention includes:

[0015] Weigh each component according to the weight ratio. After mixing PBT resin, dimethyl silicone oil, film-forming agent, zirconium phosphate, and additives, add them to the main feeding port of a twin-screw extruder. The halogen-free flame retardant and glass fiber are added through the side feeding port of the twin-screw extruder. After traction, cooling, pelletizing, and drying, the PBT composition is obtained.

[0016] Preferably, the temperature of the twin-screw extruder is set at 220 - 260 °C, and the screw speed is 200 - 600 revolutions per minute.

[0017] An application of the PBT composition of the present invention in contact with silicone rubber seals, such as charging gun plugs, connectors, and connectors, etc.

[0018] In the automotive three-electric system, when the rubber seal contacts the halogen-free flame-retardant PBT material, plastic deformation, decreased elasticity, and even embrittlement occur during long-term use, resulting in the failure of the sealing performance and the risk of failure of the corresponding part functions. Under high-temperature working conditions, the film-forming agent and zirconium phosphate effectively block the contact between the flame retardant in the flame-retardant PBT material and the silicone rubber. At the same time, dimethyl silicone oil is damaged by the flame retardant prior to the silicone rubber. Overall, the film-forming agent, zirconium phosphate, and dimethyl silicone oil can slow down the contact or reaction between the silicone rubber and the flame retardant component in the halogen-free flame-retardant PBT material, thereby effectively extending the service life of the rubber seal.

[0019] Beneficial effects

[0020] The PBT composition of the present invention has a good performance retention rate of tensile strength after aging. At the same time, when the PBT composition of the present invention is applied to the scenario of contacting with the rubber seal, the permanent deformation amount after the rubber seal contacts the halogen-free flame-retardant reinforced PBT material is reduced, that is, the rebound performance retention rate is increased. Detailed implementation manners

[0021] The following combines specific embodiments to further illustrate the present invention. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0022] I. Source of raw materials

[0023] PBT resin: Yizheng Chemical Fiber, typical grade PBT GX122J;

[0024] Halogen-free flame retardant: Aluminum diethylphosphinate, Qingdao Opure New Materials Co., Ltd., typical grade is ADP-33P;

[0025] Glass fiber: Jushi, typical grade is ECS11-4.5-534A;

[0026] Dimethyl silicone oil: Qianyan Chemical Technology (Wuhan) Co., Ltd., chemically pure, molecular weight 162.38 g / mol;

[0027] Film-forming agent - 1: Epoxidized soybean oil, purity ≥99%, from Jinan Hongli Chemical Co., Ltd.;

[0028] Film-forming agent - 2: Dipentaerythritol, Qianyan Chemical Technology (Wuhan) Co., Ltd., chemically pure, molecular weight 254.28 g / mol;

[0029] Film-forming agent - 3: Polyvinyl alcohol, Jinan Chuangshi Chemical Co., Ltd.;

[0030] Zirconium phosphate: Chemically pure, molecular weight 189.22 g / mol, from Zhengzhou Boxuan Chemical Products Co., Ltd.;

[0031] Auxiliary agent: Antioxidant 1010, antioxidant 168, lubricant PETS, mass ratio is 1:1:1;

[0032] The auxiliary agents used in the parallel examples and comparative examples are the same commercially available products.

[0033] II. Preparation methods of examples and comparative examples

[0034] Weigh each component according to the weight ratio. After mixing PBT resin, dimethyl silicone oil, film-forming agent, zirconium phosphate, and auxiliary agent, add them to the main feeding port of the twin-screw extruder. The halogen-free flame retardant and glass fiber are added through the side feeding port of the twin-screw extruder. After traction, cooling, pelletizing, and drying, a PBT composition is obtained. The temperature of the twin-screw extruder is set at 240 °C, the screw speed is 300 revolutions per minute, and the screw length-diameter ratio is 28.

[0035] III. Test standards and methods

[0036] Tensile strength test evaluation method: According to the ISO 527-1 / 2:2012 standard, test the tensile strength of the test specimen at 23 °C;

[0037] Long-term thermal aging test method: According to the ISO188:2023 standard, place the test specimen in a thermal aging oven at 150 °C for a continuous aging time of 1000 hours, and then test the tensile strength.

[0038] Compression set: ASTM D 395-2016. Test the contact between the standard rubber sample and different flame-retardant reinforced PBT materials using a compression set tester. Place the device in a 150 °C heat aging oven, measure the thickness after 1000 h of aging, and record the compression set of the rubber sample.

[0039] Table 1 Example formulation (parts by weight)

[0040]

[0041]

[0042] Table 2 Comparative example formulation (parts by weight)

[0043] Comparative example 1 Comparative example 2 Comparative example 3 PBT resin 38 38 38 Halogen-free flame retardant 20 20 20 Glass fiber 30 30 30 Dimethyl silicone oil 0.2 1 1.9 Film-forming agent - 1 5.8 0.5 5 Zirconium phosphate 1 5.5 0.1 Auxiliary agent 0.6 0.6 0.6

[0044] Table 3 Performance effect data of the examples

[0045]

[0046] Table 4 Performance effect data of the comparative examples

[0047]

[0048] The tensile strength retention rate of the PBT composition of the present invention after aging reaches more than 80%, and at the same time, the compression set after long-term contact between silicone rubber and halogen-free flame-retardant PBT material is 34.1% or less. It can be seen from the examples and comparative examples that the film-forming agent, dimethyl silicone oil, and zirconium phosphate can significantly improve the tensile strength retention rate after aging and the compression set after long-term contact between silicone rubber and halogen-free flame-retardant PBT material.

[0049] It can be seen from Examples 4-6 and Examples 11-12 that when the film-forming agents are used in combination, the compression set of the silicone rubber standard sample after aging at 150 °C / 1000 h is less than 30%.

Claims

1. A PBT composition, characterized in that, By weight parts, the components include: 30 - 50 parts of PBT resin; 17 - 30 parts of halogen-free flame retardant; 25 - 38 parts of glass fiber; 0.5 - 2 parts of dimethyl silicone oil; 1 - 6 parts of film-forming agent; 0.3 - 2 parts of zirconium phosphate; 0 - 2 parts of additives; Wherein the film-forming agent is one or more of epoxy soybean oil, polyvinyl alcohol, dipentaerythritol; Wherein the additives are one or more of antioxidants, lubricants.

2. The PBT composition according to claim 1, characterized in that, The halogen-free flame retardant is one or more of aluminum hypophosphite, aluminum diethyl phosphinate, melamine cyanurate.

3. The PBT composition according to claim 1, wherein The film-forming agent is epoxy soybean oil and polyvinyl alcohol with a mass ratio of (4:1) to (2:3); or epoxy soybean oil and dipentaerythritol with a mass ratio of (4:1) to (2:3).

4. The PBT composition according to claim 3, characterized in that, The film-forming agent is epoxy soybean oil and polyvinyl alcohol with a mass ratio of (3:2) to (1:1); or epoxy soybean oil and dipentaerythritol with a mass ratio of (3:2) to (1:1).

5. The PBT composition according to claim 1, wherein The antioxidant is one or more of hindered phenols, thioesters; the lubricant is one or more of amide lubricants.

6. The PBT composition according to claim 1, characterized in that, By weight parts, the components include: 35 - 45 parts of PBT resin; 18 - 20 parts of halogen-free flame retardant; 28 - 35 parts of glass fiber; 1 - 1.5 parts of dimethyl silicone oil; 2 - 5 parts of film-forming agent; 0.5 - 1.5 parts of zirconium phosphate; 0.3 - 1 part of additives.

7. A preparation method of the PBT composition according to claim 1, comprising: Weigh each component according to the weight ratio, mix PBT resin, dimethyl silicone oil, film-forming agent, zirconium phosphate, additives and add them into the main feeding port of the extruder, add the halogen-free flame retardant and glass fiber from the side feeding port of the twin-screw extruder, and after traction, cooling, pelletizing, and drying, obtain the PBT composition.

8. An application of the PBT composition according to claim 1 in contact with a silicone rubber sealing ring.

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