High-performance ultrahigh-viscosity PBT composite material and preparation method thereof

Abstract

The invention discloses a preparation method of a high-performance ultrahigh-viscosity PBT (Polybutylene Terephthalate) composite material, which comprises the following steps: S1, gradually heating trichlorophosphate and diamine under the action of alkali metal carbonate or alkali metal bicarbonate to carry out substitution reaction to obtain an amino phosphotriester branching agent; s2, mixing the amino phosphotriester branching agent obtained in the step S1 with PBT resin and an auxiliary agent according to a certain proportion, and adding the mixture into a double-screw extruder for melt blending to obtain the high-performance ultrahigh-viscosity PBT composite material. According to the preparation method disclosed by the invention, the viscosity of the PBT material is remarkably improved, the mechanical property and the thermal stability are greatly enhanced, the PBT material has excellent viscosity and mechanical property, meanwhile, good processability and thermal stability are ensured, and the overall comprehensive performance is excellent; the strict requirements on long-term durability and stability of the material in the high-performance application fields such as electronics, automobiles and aerospace can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of PBT materials, and in particular to a high-performance ultra-high-viscosity PBT composite material and a preparation method thereof. Background Art

[0002] Polybutylene terephthalate (PBT) is an important engineering plastic, widely used in electronics, automotive, and machinery due to its excellent mechanical properties, chemical resistance, and processing capabilities. However, conventional PBT materials have several limitations. First, the high flexibility and regularity of PBT's molecular chains result in weak intermolecular forces and low viscosity, making it difficult to meet the demands of high-performance applications. Second, PBT readily crystallizes during processing, leading to weak molecular chain entanglement and interactions at the interface between crystalline and amorphous regions, further reducing the material's viscosity. Furthermore, conventional PBT materials suffer from poor thermal stability and flame retardancy, limiting their application in applications requiring high temperatures and fire protection. These issues hinder the widespread application of PBT materials in higher-performance applications. Therefore, the development of composite materials and their preparation methods that can effectively enhance the viscosity, mechanical properties, and thermal stability of PBT materials has become an important research direction. Summary of the Invention

[0003] In view of the above shortcomings of the existing technology, the present invention provides a method for preparing a high-performance ultra-high-viscosity PBT composite material to solve the technical problems of traditional PBT materials such as low viscosity, insufficient mechanical properties, poor thermal stability and poor flame retardancy.

[0004] In order to achieve the above objects, the technical solution adopted by the present invention is: A method for preparing a high-performance ultra-high-viscosity PBT composite material, the method comprising the following steps: S1: Trichlorophosphate and diamine are subjected to a substitution reaction under the action of an alkali metal carbonate or an alkali metal bicarbonate, and the temperature is gradually increased to obtain an amino phosphate triester branching agent; S2: The aminophosphoric acid triester branching agent obtained in step S1 is mixed with PBT resin and additives in a certain proportion, and added into a twin-screw extruder for melt blending to obtain the high-performance ultra-high-viscosity PBT composite material.

[0005] In step S1 of the present invention, an amino phosphate triester branching agent is synthesized by reacting trichlorophosphate with a diamine under the action of an alkali metal carbonate or alkali metal bicarbonate. This process solves the problems of weak intermolecular forces, low viscosity, and easy crystallization during processing, which further reduces viscosity, caused by the flexibility and regularity of the molecular chain of traditional PBT materials. The synthesized branching agent not only enhances the reactivity and compatibility with the PBT molecular chain through the NH functional group, but also increases the complexity and entanglement of the molecular chain through the branched structure, thereby significantly improving the mechanical properties and thermal stability of the material. At the same time, the introduction of phosphorus-based flame retardant groups provides PBT materials with good flame retardant properties and broadens its application range. In step S2, the synthesized amino phosphate triester branching agent is mixed with PBT resin and auxiliary agents in a certain proportion and melt blended, further solving the problems of low viscosity, insufficient mechanical properties, and poor processing properties of composite materials prepared with pure PBT resin. The addition of the branching agent effectively increases the viscosity of the composite material and the interaction between the molecular chains, thereby improving mechanical properties such as tensile strength, flexural strength, and modulus. The addition of additives further optimizes the composite's performance. For example, antioxidants and heat stabilizers enhance thermal stability and durability, lubricants improve processing performance, and antistatic agents and UV absorbers enhance surface properties and weather resistance. This mixing process ultimately results in a high-performance, ultra-high-viscosity PBT composite material with exceptional viscosity, mechanical properties, processing performance, and overall performance, meeting the demands of a wide range of high-performance applications.

[0006] As a preferred technical solution, the trichlorophosphate is tris(2-chloroethyl) phosphate and / or tris(2-chloropropyl) phosphate.

[0007] As a preferred technical solution, the diamine is 1,3-adamantane diethylamine and / or adamantane-1,3-dimethylamine. The introduction of the adamantane structure significantly enhances the steric hindrance of the molecular chain, increasing its complexity and entanglement, thereby significantly improving the material's viscosity and mechanical properties. Furthermore, the high thermal and chemical stability of the adamantane structure further enhances the material's durability and flame retardancy.

[0008] As a preferred technical solution, the alkali metal carbonate is sodium carbonate or potassium carbonate; the alkali metal bicarbonate is sodium bicarbonate or potassium bicarbonate.

[0009] As a preferred technical solution, the substitution reaction is first stirred at 0-5°C for 2-6 hours; then heated to 20-30°C for 2-6 hours; and finally heated to 70-80°C for 6-10 hours.

[0010] As a preferred technical solution, the intrinsic viscosity of the PBT resin is 0.8 to 1.0 dl / g.

[0011] As a preferred technical solution, the temperatures of each section of the twin-screw extruder from one section to the head are 165°C, 170°C, 175°C, 180°C, 180°C, 175°C, 170°C, and 165°C respectively; the screw speed of the twin-screw extruder is 80-120r / min.

[0012] As a preferred technical solution, the auxiliary agent is at least one of a lubricant, an antistatic agent, an ultraviolet absorber and a pigment.

[0013] As a preferred technical solution, the mass ratio of the aminophosphoric acid triester branching agent to the PBT resin and the additive is 5-15:100:0.5-3.5.

[0014] Another aspect of the present invention is to provide a high-performance ultra-high-viscosity PBT composite material, which is prepared using the above-mentioned method for preparing a high-performance ultra-high-viscosity PBT composite material.

[0015] Beneficial effects of the present invention: The present invention's method for preparing a high-performance, ultra-high-viscosity PBT composite material innovatively introduces an aminophospho-triester branching agent into the PBT resin, significantly increasing the viscosity of the PBT material while also significantly enhancing its mechanical properties and thermal stability. This design not only strengthens the interactions between molecular chains but also maintains the material's excellent processing properties, helping to improve the material's stability under high-temperature processing conditions.

[0016] In general, the high-performance ultra-high-viscosity PBT composite material of the present invention not only has excellent viscosity and mechanical properties, but also has good thermal stability, flame retardancy and durability, and can meet the strict requirements of high-performance application fields such as electronics, automobiles, aerospace, etc. for the long-term durability and stability of materials. DETAILED DESCRIPTION

[0017] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations. Example 1

[0018] The method for preparing the high-performance ultra-high-viscosity PBT composite material of this embodiment comprises the following steps: S1: Tris(2-chloroethyl) phosphate and 1,3-adamantanediethylamine were subjected to a substitution reaction in the presence of sodium carbonate at a gradually elevated temperature to yield an aminophospho-triester branching agent. The specific process is as follows: First, 100 g of tris(2-chloroethyl) phosphate and an appropriate amount of solvent (acetone and deionized water in a 2:1 volume ratio) were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. Subsequently, 50 g of 1,3-adamantanediethylamine and 10 g of sodium carbonate were added. The reaction system was cooled to 2°C in a low-temperature water bath and stirred at 200 rpm under nitrogen for 4 hours. Subsequently, the reaction system was heated to 25°C and stirred for another 4 hours. Finally, the reaction temperature was raised to 75°C and stirred for 8 hours. After the reaction, the reaction mixture was cooled to room temperature, washed three times with deionized water and ethanol, filtered, and dried in a vacuum oven at 80°C for 24 hours to yield the aminophospho-triester branching agent.

[0019] S2: The aminophospho-triester branching agent prepared in step S1 is mixed with PBT resin and additives in a mass ratio of 10:100:1. The specific steps are as follows: First, accurately weigh 10g of the aminophospho-triester branching agent, 100g of PBT resin with an intrinsic viscosity of 0.9 dl / g, and 1g of the additives. These ingredients are added to a high-speed mixer and premixed at 800 rpm for 5 minutes to ensure that all components are fully dispersed. Subsequently, the mixed materials are added to the hopper of a twin-screw extruder. The twin-screw extruder is set to 165°C, 170°C, 175°C, 180°C, 180°C, 175°C, 170°C, and 165°C from the first section to the die head, respectively, and the screw speed is set to 100 rpm. In the twin-screw extruder, the materials undergo a series of processes, including melting, shearing, and mixing, until they are fully melted and blended and extruded from the die head. The extruded material is cooled and shaped in a cooling water tank, and then cut into uniform particles by a pelletizer to obtain a high-performance ultra-high-viscosity PBT composite material.

[0020] The auxiliary agent is composed of the following raw materials in parts by weight: 0.5 parts of lubricant (polyethylene wax), 0.3 parts of antistatic agent (dodecyl dimethyl betaine), 0.1 parts of ultraviolet absorber (2-hydroxy-4-methoxybenzophenone) and 0.1 parts of pigment (titanium dioxide). Example 2

[0021] The method for preparing the high-performance ultra-high-viscosity PBT composite material of this embodiment comprises the following steps: S1: Tris(2-chloropropyl) phosphate and adamantane-1,3-dimethylamine were subjected to a substitution reaction in the presence of potassium carbonate at a gradually elevated temperature to produce an aminophosphotriester branching agent. The specific process is as follows: First, 120 g of tris(2-chloropropyl) phosphate and an appropriate amount of solvent (acetone and deionized water in a 2:1 volume ratio) were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. Subsequently, 60 g of adamantane-1,3-dimethylamine and 15 g of potassium carbonate were added. The reaction system was cooled to 0°C in a low-temperature water bath and stirred at 250 rpm under nitrogen for 3 hours. The reaction system was then heated to 25°C and stirred for a further 5 hours. Finally, the reaction temperature was raised to 70°C and stirred for 10 hours. After the reaction, the reaction mixture was cooled to room temperature, washed three times with deionized water and ethanol, filtered, and dried in a vacuum oven at 85°C for 24 hours to produce the aminophosphotriester branching agent.

[0022] S2: The aminophospho-triester branching agent prepared in step S1 is mixed with PBT resin and additives in a mass ratio of 12:100:1.5. The specific steps are as follows: First, accurately weigh 12g of the aminophospho-triester branching agent, 100g of PBT resin with an intrinsic viscosity of 0.9 dl / g, and 1.5g of the additives. These ingredients are added to a high-speed mixer and premixed at 850 rpm for 6 minutes to ensure that all components are fully dispersed. Subsequently, the mixed materials are added to the hopper of a twin-screw extruder. The twin-screw extruder is set to 165°C, 170°C, 175°C, 180°C, 180°C, 175°C, 170°C, and 165°C from the first section to the die head, respectively, and the screw speed is set to 110 rpm. In the twin-screw extruder, the materials undergo a series of processes including melting, shearing, and mixing, and are fully melted and blended before being extruded from the die head. The extruded material is cooled and shaped in a cooling water tank, and then cut into uniform particles by a pelletizer to obtain a high-performance ultra-high-viscosity PBT composite material.

[0023] The auxiliary agent is composed of the following raw materials in parts by weight: 0.6 parts of lubricant (polyethylene wax), 0.4 parts of antistatic agent (dodecyl dimethyl betaine), 0.2 parts of ultraviolet absorber (2-hydroxy-4-methoxybenzophenone) and 0.3 parts of pigment (titanium dioxide). Example 3

[0024] The method for preparing the high-performance ultra-high-viscosity PBT composite material of this embodiment comprises the following steps: S1: Tris(2-chloroethyl) phosphate and 1,3-adamantanediethylamine were subjected to a substitution reaction in the presence of sodium bicarbonate at a gradually elevated temperature to produce an aminophospho-triester branching agent. The specific process is as follows: First, 150 g of tris(2-chloroethyl) phosphate and an appropriate amount of solvent (acetone and deionized water in a 2:1 volume ratio) were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. Subsequently, 70 g of 1,3-adamantanediethylamine and 20 g of sodium bicarbonate were added. The reaction system was cooled to 5°C in a low-temperature water bath and stirred at 300 rpm under nitrogen for 2 hours. Subsequently, the reaction system was heated to 20°C and stirred for another 6 hours. Finally, the reaction temperature was raised to 80°C and stirred for another 6 hours. After the reaction, the reaction mixture was cooled to room temperature, washed three times with deionized water and ethanol, filtered, and dried in a vacuum oven at 90°C for 24 hours to produce the aminophospho-triester branching agent.

[0025] S2: The aminophospho-triester branching agent prepared in step S1 is mixed with PBT resin and additives in a mass ratio of 15:100:3. The specific steps are as follows: First, accurately weigh 15g of the aminophospho-triester branching agent, 100g of PBT resin with an intrinsic viscosity of 0.85 dl / g, and 3g of the additives. These ingredients are added to a high-speed mixer and premixed at 900 rpm for 4 minutes to ensure that all components are fully dispersed. Subsequently, the mixed materials are added to the hopper of a twin-screw extruder. The twin-screw extruder is set to 165°C, 170°C, 175°C, 180°C, 180°C, 175°C, 170°C, and 165°C from the first section to the die head, respectively, and the screw speed is set to 90 rpm. In the twin-screw extruder, the materials undergo a series of actions, including melting, shearing, and mixing, until they are fully melted and blended and extruded from the die head. The extruded material is cooled and shaped in a cooling water tank, and then cut into uniform particles by a pelletizer to obtain a high-performance ultra-high-viscosity PBT composite material.

[0026] The auxiliary agent is composed of the following raw materials in parts by weight: 1.0 part of lubricant (polyethylene wax), 0.75 part of antistatic agent (dodecyl dimethyl betaine), 0.5 part of ultraviolet absorber (2-hydroxy-4-methoxybenzophenone) and 0.75 part of pigment (titanium dioxide).

[0027] The high performance and ultra-high viscosity PBT composite materials prepared in Examples 1 to 3 were subjected to performance tests, and the performance results are shown in Table 1: The intrinsic viscosity test is based on GB / T 1632. The PBT composite material to be tested is first dissolved in an appropriate solvent (a 1:1 volume ratio mixture of phenol and carbon tetrachloride) to prepare a 0.5 g / dL solution. The test is performed using an Ubbelohde viscometer, ensuring it is clean and free of bubbles. The viscometer is maintained in a constant-temperature water bath at 25°C, and the time the solution passes through the viscometer is recorded. The reduced viscosity is calculated using the formula ηsp = (t − t0) / t0, where t is the solution flow time and t0 is the pure solvent flow time. The intrinsic viscosity is then calculated using a graphical method or the Mark-Houwink equation.

[0028] Mechanical Properties Testing: Mechanical properties testing includes tensile strength and flexural strength, and is conducted in accordance with GB / T 1040 (tensile properties) and GB / T 9341 (flexural properties). Before testing, standard-sized tensile and flexural specimens were prepared according to the standards and tested using a universal materials testing machine to ensure accurate calibration. Tensile testing was conducted at 23°C ± 2°C and 50% ± 5% relative humidity, at a tensile speed of 50 mm / min. Flexural testing was conducted under the same conditions at a flexural speed of 2 mm / min. The maximum load during the tensile and flexural tests was recorded, and the tensile and flexural strengths were calculated to evaluate the mechanical properties of the material.

[0029] Thermal performance testing focuses on heat deflection temperature (HDT), which is tested according to GB / T 1634. Standard-sized specimens (typically 80 mm × 10 mm × 4 mm) are prepared and tested using a heat deflection temperature tester, ensuring accurate calibration. Testing is performed under a load of 1.8 MPa at a heating rate of 120°C / h, and the temperature at which the specimen deforms 0.2 mm is recorded. This recorded temperature data is used to assess the thermal and dimensional stability of the material under high-temperature conditions.

[0030] Flame retardancy testing: This is primarily assessed through the vertical burning rating (UL-94), based on UL 94. Before testing, prepare a standard-sized specimen, typically 125mm x 13mm x 3mm, and use a vertical burning tester to ensure accurate calibration. The specimen is fixed vertically on a bracket, and the base of the specimen is ignited. The burning behavior is observed, and the burning time and self-extinguishing time are recorded. Based on the burning behavior and self-extinguishing time, the vertical burning rating is determined to assess the flame retardant performance of the material.

[0031]

[0032] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements are possible without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A method for preparing a high-performance ultra-high-viscosity PBT composite material, characterized in that: The preparation method comprises the following steps: S1: Trichlorophosphate and diamine are subjected to a substitution reaction under the action of an alkali metal carbonate or an alkali metal bicarbonate, and the temperature is gradually increased to obtain an amino phosphate triester branching agent; S2: The aminophosphoric acid triester branching agent obtained in step S1 is mixed with PBT resin and additives in a certain proportion, and added into a twin-screw extruder for melt blending to obtain the high-performance ultra-high-viscosity PBT composite material.

2. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The trichlorophosphate is tris(2-chloroethyl)phosphate and / or tris(2-chloropropyl)phosphate.

3. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The diamine is 1,3-adamantane diethylamine and / or adamantane-1,3-dimethylamine.

4. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The alkali metal carbonate is sodium carbonate or potassium carbonate; the alkali metal bicarbonate is sodium bicarbonate or potassium bicarbonate.

5. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The substitution reaction is first carried out at 0-5° C. with stirring for 2-6 hours; then the temperature is raised to 20-30° C. with stirring for 2-6 hours; and finally the temperature is raised to 70-80° C. with stirring for 6-10 hours.

6. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The intrinsic viscosity of the PBT resin is 0.8-1.0 dl / g.

7. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The temperatures of the twin-screw extruder from one section to the die head are 165°C, 170°C, 175°C, 180°C, 180°C, 175°C, 170°C, and 165°C respectively; the screw speed of the twin-screw extruder is 80-120r / min.

8. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The auxiliary agent is at least one of a lubricant, an antistatic agent, an ultraviolet absorber and a pigment.

9. The method for preparing a high-performance ultra-high-viscosity PBT composite material according to claim 1, wherein: The mass ratio of the aminophosphoric acid triester branching agent to the PBT resin and the auxiliary agent is 5-15:100:0.5-3.

5.

10. A high-performance ultra-high-viscosity PBT composite material, characterized in that: The PBT composite material is prepared by the preparation method of the high-performance ultra-high-viscosity PBT composite material according to any one of claims 1 to 9.

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