Environment-friendly high-thermal-conductivity polyester material and preparation process thereof

Abstract

The invention relates to the technical field of PET polyester, and discloses an environment-friendly high-thermal-conductivity polyester material and a preparation process thereof.The polyester material comprises, by weight, 100 parts of polyethylene glycol terephthalate, 10-40 parts of hexagonal boron nitride and 0.5-2.5 parts of sodium polyethyleneimine urea carboxylate; polyethyleneimine ureido sodium carboxylate contains a large amount of active amine activity and sodium carboxylate groups, surface modification of boron nitride is effectively achieved, dispersity of boron nitride can be improved, compatibility with PET is better, the polyester material can keep good mechanical property and tensile strength, and the heat conductivity coefficient and heat conduction and heat dissipation performance of the material are improved. Meanwhile, the surface water contact angle of the polyester material is reduced, and the antistatic performance of the polyester material is improved.

Description

Technical Field

[0001] This invention relates to the field of PET polyester technology, specifically to an environmentally friendly high thermal conductivity polyester material and its preparation process. Background Technology

[0002] Boron nitride possesses high thermal conductivity, mechanical strength, and high-temperature resistance, making it widely used in polymer materials such as plastics and rubber to effectively improve their thermal conductivity and heat dissipation. However, improving the dispersion modification of boron nitride to enhance its compatibility with the material matrix remains a research challenge. Furthermore, the high insulating properties of added boron nitride can negatively impact the material's electrical conductivity and antistatic properties.

[0003] Polyethylene terephthalate (PET) is biodegradable, environmentally friendly, and boasts high mechanical strength and good heat resistance, making it widely applicable. However, ordinary PET has a low thermal conductivity, which hinders its practical application in thermally conductive materials and electronic components. Adding thermally conductive fillers such as boron nitride can improve its thermal conductivity; however, excessive addition of boron nitride, due to poor dispersibility, can negatively impact the material's mechanical properties. Summary of the Invention

[0004] (a) Technical problem solved: The present invention solves the problem of poor thermal conductivity and other properties of PET polyester material, while maintaining good mechanical strength.

[0005] (II) The adopted technical solution is: an environmentally friendly, high thermal conductivity polyester material, comprising 100 parts by weight of polyethylene terephthalate, 10-40 parts by weight of hexagonal boron nitride, and 0.5-2.5 parts by weight of sodium polyethyleneimine ureacarboxylate; the preparation process of the polyester material is as follows: (1) Polyethyleneimine, methyl 4-isocyanate benzoate (CAS No. 23138-53-6), and dibutyltin dilaurate (DBTDL) were added to the reaction solvent. After stirring and reacting, the mixture was distilled under reduced pressure. The product was added to water, stirred, and filtered. Sodium hydroxide was added to the filtrate to carry out a hydrolysis reaction. The mixture was heated to evaporate, cooled to crystallize, and the product was added to water for a second recrystallization to obtain sodium polyethyleneimine ureacarboxylate. The reaction formula is as follows: .

[0006] (2) Add hexagonal boron nitride and sodium polyimide ureacarboxylate to water, stir and disperse, dry and remove water, then mix the mixture with polyethylene terephthalate in a mixer, and then melt, extrude and pelletize through a twin-screw extruder to obtain environmentally friendly high thermal conductivity polyester material.

[0007] Preferably, the solvent in (1) is dichloromethane, trichloromethane or tetrahydrofuran.

[0008] Preferably, in (1), the amount of polyethyleneimine is 100 parts by weight, methyl 4-isocyanate is 10-30 parts by weight, and dibutyltin dilaurate is 0.2-0.5 parts by weight.

[0009] Preferably, in (1), the stirring reaction is refluxed at 40-65℃ for 12-18h.

[0010] Preferably, the hydrolysis reaction in (1) is carried out at 70-90℃ for 2-4 hours.

[0011] Preferably, the temperature during stirring and dispersion in (2) is 20-50℃ and the time is 3-6h.

[0012] Preferably, in (2), the mixing temperature of the mixer is 60-80℃ and the mixing time is 20-30min.

[0013] Preferably, in (2), the temperature of each zone of the twin-screw extruder is 230-265℃ and the screw speed is 80-150r / min.

[0014] (III) Beneficial Technical Effects: This invention uses environmentally friendly and biodegradable polyethylene terephthalate (PET) as the matrix and sodium polyethyleneimine ureacarboxylate as the dispersant. Sodium polyethyleneimine ureacarboxylate contains a large number of active amine groups and sodium carboxylate groups, which can form a stronger interaction with the surface of boron nitride, effectively modifying the surface of boron nitride and improving its dispersibility. Furthermore, the urea groups in sodium polyethyleneimine ureacarboxylate contain more -NH bonds (-NH-CO-NH-), forming stronger hydrogen bonds with the terminal hydroxyl groups of PET, resulting in better compatibility between the modified boron nitride and PET, allowing the polyester material to maintain good mechanical properties and tensile strength.

[0015] The boron nitride modified by this invention is uniformly dispersed in the polyester matrix to form a continuous thermally conductive network, which significantly improves the thermal conductivity and heat dissipation performance of the material.

[0016] In this invention, polyethyleneimine itself has excellent ionic conductivity and hydrophilicity. At the same time, the introduction of hydrophilic sodium carboxylate and urea groups significantly reduces the surface water contact angle of the polyester material, forming a water molecule layer and ion channels on the surface of the polyester material, promoting charge dissipation, and thus improving the antistatic properties of the polyester material. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 (1) Add 20g polyethyleneimine, 4g methyl 4-isocyanate and 0.07g dibutyltin dilaurate to 300mL tetrahydrofuran, heat to 65℃, stir and reflux for 12h, distill under reduced pressure, add the product to 300mL water, stir and filter, add 36g sodium hydroxide to the filtrate, heat to 90℃, stir and hydrolyze for 2h, heat to evaporate, cool and crystallize, add the product to water, recrystallize a second time to obtain sodium polyethyleneimine ureacarboxylate.

[0019] (2) Add 100g of hexagonal boron nitride (average particle size 3μm) and 5g of sodium polyimide ureacarboxylate to 2L of water, stir and disperse at 50℃ for 3h, dry and remove water, then mix the mixture with 1kg of polyethylene terephthalate in a mixer at 80℃ for 20min, and then melt mix through a twin-screw extruder with temperatures of 230℃, 245℃, 255℃, 265℃ and 255℃ in each zone and a screw speed of 80r / min, extrude and pelletize to obtain environmentally friendly high thermal conductivity polyester material.

[0020] Comparative Example 1 (1) 100g of hexagonal boron nitride and 1kg of polyethylene terephthalate were mixed in a mixer at 80°C for 20min. Then, the mixture was melt-mixed in a twin-screw extruder at temperatures of 230°C, 245°C, 255°C, 265°C and 255°C, with a screw speed of 80r / min. The mixture was then extruded and pelletized to obtain an environmentally friendly high thermal conductivity polyester material.

[0021] Comparative Example 2 (1) Add 100g of hexagonal boron nitride and 5g of polyethyleneimine to 2L of water, stir and disperse at 50℃ for 3h, dry and remove water, then mix the mixture with 1kg of polyethylene terephthalate in a mixer at 80℃ for 20min, and then melt mix through a twin-screw extruder with temperatures of 230℃, 245℃, 255℃, 265℃ and 255℃ in each zone and a screw speed of 80r / min. Extrude and pelletize to obtain environmentally friendly high thermal conductivity polyester material.

[0022] Comparative Example 3 (1) Add 20g of polyethyleneimine and 4g of sodium chloroacetate to 300mL of water, add sodium carbonate to adjust the pH to 9, heat to 65℃, stir and react for 12h, heat to evaporate, cool and crystallize, add the product to water, recrystallize a second time to obtain sodium polyethyleneimine carboxylate.

[0023] (2) Add 100g of hexagonal boron nitride and 5g of sodium polyimide carboxylate to 2L of water, stir and disperse at 50℃ for 3h, dry and remove water, then mix the mixture with 1kg of polyethylene terephthalate in a mixer at 80℃ for 20min, and then melt mix through a twin-screw extruder with temperatures of 230℃, 245℃, 255℃, 265℃ and 255℃ in each zone and a screw speed of 80r / min. Extrude and pelletize to obtain environmentally friendly high thermal conductivity polyester material.

[0024] Comparative Example 4 (1) Add 100g of hexagonal boron nitride and 5g of sodium stearate to 2L of water, stir and disperse at 50℃ for 3h, dry and remove water, then mix the mixture with 1kg of polyethylene terephthalate in a mixer at 80℃ for 20min, and then melt mix through a twin-screw extruder with temperatures of 230℃, 245℃, 255℃, 265℃ and 255℃ in each zone and a screw speed of 80r / min. Extrude and pelletize to obtain environmentally friendly high thermal conductivity polyester material.

[0025] Example 2 (1) Add 20g polyethyleneimine, 6g methyl 4-isocyanate and 0.1g dibutyltin dilaurate to 400mL dichloromethane, heat to 40℃, stir and reflux for 18h, distill under reduced pressure, add the product to 300mL water, stir and filter, add 40g sodium hydroxide to the filtrate, heat to 70℃, stir and hydrolyze for 4h, heat to evaporate, cool and crystallize, add the product to water, recrystallize a second time to obtain sodium polyethyleneimine ureacarboxylate.

[0026] (2) Add 250g of hexagonal boron nitride and 15g of sodium polyimide ureacarboxylate to 4L of water, stir and disperse at 20℃ for 6h, dry and remove water, then mix the mixture with 1kg of polyethylene terephthalate in a mixer at 60℃ for 30min, and then melt mix through a twin-screw extruder with temperatures of 230℃, 245℃, 255℃, 265℃ and 255℃ in each zone and a screw speed of 150r / min. Extrude and pelletize to obtain environmentally friendly high thermal conductivity polyester material.

[0027] Example 3 (1) Add 20g polyethyleneimine, 2g methyl 4-isocyanate and 0.04g dibutyltin dilaurate to 300mL of chloroform, heat to 60℃, stir and reflux for 12h, distill under reduced pressure, add the product to 250mL of water, stir and filter, add 30g sodium hydroxide to the filtrate, heat to 75℃, stir and hydrolyze for 4h, heat to evaporate, cool and crystallize, add the product to water, recrystallize a second time to obtain sodium polyethyleneimine ureacarboxylate.

[0028] (2) Add 400g of hexagonal boron nitride and 25g of sodium polyimide ureacarboxylate to 5L of water, stir and disperse at 40℃ for 3h, dry and remove water, then mix the mixture with 1kg of polyethylene terephthalate in a mixer at 80℃ for 20min, and then melt mix through a twin-screw extruder with temperatures of 230℃, 245℃, 255℃, 265℃ and 255℃ in each zone and a screw speed of 150r / min. Extrude and pelletize to obtain environmentally friendly high thermal conductivity polyester material.

[0029] Polyester material was injection molded into specimens using an injection molding machine, and its tensile properties were tested according to GB / T 1040.1-2018. Thermal conductivity was tested according to GB / T 3399-1982. Polyester material was molded into films, and the water contact angle was tested according to GB / T 30693-2014.

[0030] Table 1 Properties of Polyester The polyester material in Comparative Example 1 has low tensile strength and thermal conductivity, mainly because hexagonal boron nitride has poor compatibility with polyethylene benzoate (PET) and poor dispersion in the polyester material, which has a significant impact on the mechanical properties of the material. At the same time, it does not form a good continuous thermal conductive network, resulting in low thermal conductivity.

[0031] Example 1 utilizes sodium polyethyleneimine ureacarboxylate as a dispersant. Containing a large number of active amines and sodium carboxylate groups, it can form a stronger interaction with the surface of boron nitride, effectively modifying the surface of boron nitride and improving its dispersibility. Furthermore, the urea groups in sodium polyethyleneimine ureacarboxylate contain more -NH bonds, forming stronger hydrogen bonds with the terminal hydroxyl groups of PET, resulting in better compatibility between the modified boron nitride and PET. This allows the polyester material to maintain good mechanical properties and tensile strength. The uniform dispersion of boron nitride in the polyester matrix forms a continuous thermally conductive network, further improving the thermal conductivity. Polyethyleneimine itself has excellent ionic conductivity and hydrophilicity. The introduction of hydrophilic sodium carboxylate and urea groups significantly reduces the surface water contact angle of the polyester material, forming a water molecule layer and ion channels on the polyester surface, promoting charge dissipation and improving the antistatic properties of the polyester material.

[0032] The polyethyleneimine in Comparative Example 2 does not contain sodium carboxylate groups and urea groups, resulting in poor dispersion modification of boron nitride. The tensile strength and thermal conductivity of the polyester material are lower than those in Example 1, while the water contact angle is greater than that in Example 1, which is not conducive to improving the antistatic properties of the material.

[0033] Comparative Example 3 utilizes the reaction of chlorine atoms from sodium chloroacetate with amino groups from polyethyleneimine to obtain sodium polyethyleneimine carboxylate, which does not contain urea groups. The tensile strength and thermal conductivity of the polyester material are lower than those of Example 1, while the water contact angle is greater than that of Example 1.

[0034] Comparative Example 4 used conventional sodium stearate as a dispersant. The tensile strength and thermal conductivity of the polyester material were lower than those of Example 1, while the water contact angle was greater than that of Example 1, indicating poor dispersion performance.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly, high thermal conductivity polyester material, characterized in that, The polyester material comprises 100 parts by weight of polyethylene terephthalate, 10-40 parts by weight of hexagonal boron nitride, and 0.5-2.5 parts by weight of sodium polyethyleneimine ureacarboxylate. The sodium polyethyleneimine ureacarboxylate is prepared by the following process: polyethyleneimine, methyl 4-isocyanate benzoate, and dibutyltin dilaurate are added to the reaction solvent, the mixture is stirred and then distilled under reduced pressure. The product is added to water, stirred and filtered, sodium hydroxide is added to the filtrate, and a hydrolysis reaction is carried out. The mixture is then recrystallized to obtain sodium polyethyleneimine ureacarboxylate.

2. The environmentally friendly high thermal conductivity polyester material according to claim 1, characterized in that, The solvent is dichloromethane, trichloromethane, or tetrahydrofuran.

3. The environmentally friendly high thermal conductivity polyester material according to claim 1, characterized in that, The amount of polyethyleneimine used is 100 parts by weight, methyl 4-isocyanate is 10-30 parts by weight, and dibutyltin dilaurate is 0.2-0.5 parts by weight.

4. The environmentally friendly high thermal conductivity polyester material according to claim 1, characterized in that, The stirring reaction was refluxed at 40-65°C for 12-18 hours.

5. The environmentally friendly high thermal conductivity polyester material according to claim 1, characterized in that, The hydrolysis reaction is carried out at 70-90℃ for 2-4 hours.

6. A preparation process for an environmentally friendly high thermal conductivity polyester material as described in any one of claims 1-6, characterized in that, The preparation process is as follows: add hexagonal boron nitride and sodium polyethyleneimine ureacarboxylate to water, stir and disperse, dry and remove water, then mix the mixture with polyethylene terephthalate in a mixer, and then melt, extrude and pelletize through a twin-screw extruder to obtain an environmentally friendly high thermal conductivity polyester material.

7. The preparation process of the environmentally friendly high thermal conductivity polyester material according to claim 6, characterized in that, The temperature during stirring and dispersion is 20-50℃, and the time is 3-6 hours.

8. The preparation process of the environmentally friendly high thermal conductivity polyester material according to claim 6, characterized in that, The mixing temperature in the mixer is 60-80℃, and the mixing time is 20-30 minutes.

9. The preparation process of the environmentally friendly high thermal conductivity polyester material according to claim 6, characterized in that, The temperature of each zone of the twin-screw extruder is 230-265℃, and the screw speed is 80-150 r / min.

Images