Preparation method of high-temperature-resistant anti-aging PCT material for LED lamp beads

Abstract

The invention relates to the technical field of poly (1, 4-cyclohexanedimethanol) terephthalate, and discloses a preparation method of a high-temperature-resistant anti-aging PCT material for an LED lamp bead, and terephthalic acid, 1, 4-cyclohexanedimethanol, N-phenylmaleimide diol and a catalyst are subjected to a co-esterification polycondensation reaction to obtain the high-temperature-resistant anti-aging PCT material for the LED lamp bead. Flexible ether bonds and alkyl long chains are introduced into the PCT, so that a very good toughening effect can be achieved, and the elongation at break and the impact strength of the PCT are remarkably improved. Meanwhile, rigid N-phenylmaleimide is introduced into a side chain of the PCT, so that the heat aging resistance of the PCT is improved, the PCT still keeps relatively high mechanical properties after high-temperature heat aging treatment, and the PCT has very good practical application in the aspects of LED lamp bead materials and the like.

Description

Technical Field

[0001] The invention relates to the technical field of poly (1,4-cyclohexane dimethanol terephthalate), in particular to a method for preparing a high-temperature resistant and anti-aging PCT material for LED lamp beads. Background Art

[0002] PCT is a polymer material obtained by esterification and polycondensation of terephthalic acid and 1,4-cyclohexanedimethanol. It is a semi-crystalline thermoplastic with good chemical resistance, dimensional stability, low hygroscopicity and other properties. It is widely used in LED lamp beads, automobile manufacturing, medical equipment, instruments, optical components and other fields.

[0003] At present, the modification methods of PCT include copolymerization modification and blending modification. The patent with announcement number CN115612075B discloses a highly transparent and light-colored PCT-based random copolyester resin and its preparation method, using 2,2,4,4-tetramethyl-1,3-cyclobutanediol, isosorbide, diethylene glycol, etc. as diols, and 1,4-cyclohexanedimethanol, terephthalic acid or its dimethyl ester for co-condensation reaction, and the obtained PCT-based random copolyester resin has the advantages of high transparency, low haze, light color, etc. However, the patent does not improve the mechanical strength, toughness and high temperature aging resistance of PCT copolyester. Summary of the invention

[0004] The invention solves the problem that the mechanical properties and high temperature aging resistance of poly (1,4-cyclohexane dimethanol terephthalate) PCT material are poor.

[0005] Technical solution: A method for preparing a high-temperature resistant and anti-aging PCT material for LED lamp beads: add terephthalic acid, 1,4-cyclohexanedimethanol, N-phenylmaleimide diol and a catalyst into a reaction container equipped with a stirrer and a distillation column, introduce nitrogen, heat to 240-250°C, react for 2-4 hours, then heat to 270-280°C, react until no water is distilled out, heat to 290-300°C, evacuate to control the vacuum degree to 0.05-0.1kPa, react for 3-4 hours, introduce nitrogen to normal pressure, cool, and discharge to obtain a high-temperature resistant and anti-aging PCT material for LED lamp beads.

[0006] Preferably, the ratio of terephthalic acid, 1,4-cyclohexanedimethanol, N-phenylmaleimide diol, and catalyst is (80-85) mol: (85-97) mol: (3-15) mol: (0.03-0.04) mol.

[0007] Preferably, the catalyst comprises tetrabutyl titanate.

[0008] Preferably, the preparation method of N-phenylmaleimide diol is:

[0009] (1): Add ethanol, ethylene glycol diglycidyl ether, and N-(4-aminophenyl)maleimide to a reaction vessel equipped with a condenser reflux tube and a stirrer, heat to 45-55°C, react for 5-8 hours, distill under reduced pressure, separate on a silica gel chromatography column, and elute with a gradient of ethyl acetate and petroleum ether to obtain an intermediate. The reaction formula is as follows:

[0010]

[0011] (2): Add ethanol, intermediate, bromoalkane, and sodium carbonate to a reaction vessel equipped with a condenser reflux tube and a stirrer, heat to 50-65°C, react for 8-12 hours, distill under reduced pressure, separate on a silica gel chromatography column, and elute with ethyl acetate and petroleum ether in a gradient to obtain N-phenylmaleimide diol. The reaction formula is as follows:

[0012]

[0013] Preferably, the ratio of ethylene glycol diglycidyl ether to N-(4-aminophenyl)maleimide in (1) is 1 mol:(2.2-2.6) mol.

[0014] Preferably, in (2), the ratio of the intermediate, the alkyl bromide and the sodium carbonate is 1 mol:(2-2.6) mol:(2.4-3.2) mol.

[0015] Preferably, the molecular formula of the bromoalkane is Br-C n H 2n+1 , n is any one of 8-12.

[0016] The technical effect of the present invention is that N-phenylmaleimide diol replaces part of 1,4-cyclohexanedimethanol and undergoes a co-esterification polycondensation reaction with terephthalic acid, thereby introducing a flexible ether bond into the main chain of PCT and a flexible alkyl long chain into the side chain of PCT, showing a good toughening effect and significantly improving the elongation at break and the impact strength of PCT.

[0017] The present invention introduces rigid N-phenylmaleimide into the side chain of PCT, which can improve its strength and show good tensile strength. In addition, N-phenylmaleimide has high heat resistance and can improve the heat aging resistance of PCT. After high-temperature heat aging treatment, PCT still maintains high tensile strength, elongation at break and impact strength, and has a high mechanical property retention rate. The obtained PCT has good practical applications in LED lamp bead materials and the like. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1 (1): Into a reaction vessel equipped with a reflux condenser and a stirrer, add 2 L of ethanol, 0.5 mol of ethylene glycol diglycidyl ether, and 1.3 mol of N-(4-aminophenyl)maleimide, raise the temperature to 45°C, react for 5 h, distill under reduced pressure, separate using a silica gel chromatography column, and gradient elute with ethyl acetate and petroleum ether to obtain an intermediate.

[0020] (2): Add 2.5L ethanol, 0.5mol intermediate, 1.1mol 1-bromodecane, and 1.2mol sodium carbonate to a reaction vessel equipped with a condenser reflux tube and a stirrer, heat to 50°C, react for 12h, distill under reduced pressure, separate on a silica gel chromatography column, and gradiently elute with ethyl acetate and petroleum ether to obtain N-phenylmaleimide diol.

[0021] (3): Add 0.85 mol of terephthalic acid, 0.97 mol of 1,4-cyclohexanedimethanol, 0.03 mol of N-phenylmaleimide diol, and 0.36 mmol of catalyst tetrabutyl titanate into a reaction vessel equipped with an agitator and a distillation column, introduce nitrogen, heat to 240°C, react for 4 hours, then heat to 275°C, react until no water is distilled out, heat to 300°C, evacuate and control the vacuum degree to 0.05 kPa, react for 3 hours, introduce nitrogen to normal pressure, cool, and discharge to obtain high temperature resistant and anti-aging PCT material for LED lamp beads.

[0022] Example 2 (1): To a reaction vessel equipped with a reflux condenser and a stirrer, add 1.5 L of ethanol, 0.5 mol of ethylene glycol diglycidyl ether, and 1.1 mol of N-(4-aminophenyl)maleimide, raise the temperature to 50°C, react for 8 hours, distill under reduced pressure, separate using a silica gel chromatography column, and gradient elute with ethyl acetate and petroleum ether to obtain an intermediate.

[0023] (2): Add 3L of ethanol, 0.5mol of the intermediate, 1.3mol of 1-bromodecane, and 1.6mol of sodium carbonate to a reaction vessel equipped with a condenser reflux tube and a stirrer, raise the temperature to 50°C, react for 12h, distill under reduced pressure, separate on a silica gel chromatography column, and gradiently elute with ethyl acetate and petroleum ether to obtain N-phenylmaleimide diol.

[0024] (3): Add 0.8 mol of terephthalic acid, 0.9 mol of 1,4-cyclohexanedimethanol, 0.1 mol of N-phenylmaleimide diol, and 0.3 mmol of catalyst tetrabutyl titanate into a reaction vessel equipped with an agitator and a distillation column, introduce nitrogen, heat to 250°C, react for 2 hours, then heat to 280°C, react until no water is distilled out, heat to 300°C, evacuate and control the vacuum degree to 0.05 kPa, react for 3 hours, introduce nitrogen to normal pressure, cool, and discharge to obtain high temperature resistant and anti-aging PCT material for LED lamp beads.

[0025] Example 3 (1): To a reaction vessel equipped with a reflux condenser and a stirrer, add 2 L of ethanol, 0.5 mol of ethylene glycol diglycidyl ether, and 1.2 mol of N-(4-aminophenyl)maleimide, raise the temperature to 55°C, react for 5 h, distill under reduced pressure, separate using a silica gel chromatography column, and gradient elute with ethyl acetate and petroleum ether to obtain an intermediate.

[0026] (2): Add 2.5L ethanol, 0.5mol intermediate, 1mol 1-bromooctane, and 1.2mol sodium carbonate to a reaction vessel equipped with a condenser reflux tube and a stirrer, heat to 65°C, react for 8h, distill under reduced pressure, separate on a silica gel chromatography column, and gradient elute with ethyl acetate and petroleum ether to obtain N-phenylmaleimide diol.

[0027] (3): Add 0.8 mol of terephthalic acid, 0.85 mol of 1,4-cyclohexanedimethanol, 0.15 mol of N-phenylmaleimide diol, and 0.4 mmol of catalyst tetrabutyl titanate into a reaction vessel equipped with an agitator and a distillation column, introduce nitrogen, heat to 240°C, react for 3 hours, then heat to 270°C, react until no water is distilled out, heat to 290°C, evacuate and control the vacuum degree to 0.1 kPa, react for 4 hours, introduce nitrogen to normal pressure, cool, and discharge to obtain high temperature resistant and anti-aging PCT material for LED lamp beads.

[0028] Comparative Example 1: 0.85 mol of terephthalic acid, 1 mol of 1,4-cyclohexanedimethanol, and 0.36 mmol of catalyst tetrabutyl titanate were added to a reaction vessel equipped with an agitator and a distillation column, nitrogen was introduced, the temperature was raised to 240°C, the reaction was carried out for 4 hours, and then the temperature was raised to 275°C, the reaction was carried out until no water was distilled out, the temperature was raised to 300°C, the vacuum was controlled to 0.05 kPa, the reaction was carried out for 3 hours, nitrogen was introduced to normal pressure, the material was cooled, and the PCT material was obtained.

[0029] Comparative Example 2: Into a reaction vessel equipped with an agitator and a distillation column, 0.85 mol of terephthalic acid, 0.97 mol of 1,4-cyclohexanedimethanol, 0.03 mol of triethylene glycol and 0.36 mmol of catalyst tetrabutyl titanate were added, nitrogen was introduced, the temperature was raised to 240°C, the reaction was carried out for 4 hours, and then the temperature was raised to 275°C, the reaction was carried out until no water was distilled out, the temperature was raised to 300°C, the vacuum was controlled to 0.05 kPa, the reaction was carried out for 3 hours, nitrogen was introduced to normal pressure, the material was cooled, and the PCT material was obtained.

[0030] Comparative Example 3: (1): 2.5 L of ethanol, 0.5 mol of the intermediate (prepared in Example 1), 1.1 mol of 1-bromoethane, and 1.2 mol of sodium carbonate were added to a reaction vessel equipped with a condenser reflux tube and a stirrer, and the temperature was raised to 50° C., reacted for 12 h, and distilled under reduced pressure. The mixture was separated by a silica gel chromatography column and eluted with a gradient of ethyl acetate and petroleum ether to obtain N-phenylmaleimide diol. The structural formula is:

[0031] (2): Add 0.85 mol of terephthalic acid, 0.97 mol of 1,4-cyclohexanedimethanol, 0.03 mol of N-phenylmaleimide diol, and 0.36 mmol of catalyst tetrabutyl titanate into a reaction vessel equipped with an agitator and a distillation column, introduce nitrogen, raise the temperature to 240°C, react for 4 hours, then raise the temperature to 275°C, react until no water is distilled out, raise the temperature to 300°C, evacuate and control the vacuum degree to 0.05 kPa, react for 3 hours, introduce nitrogen to normal pressure, cool, and discharge to obtain PCT material.

[0032] 100 g of PCT material, 0.3 g of antioxidant Hostanox O3, and 1.6 g of nucleating agent (model JC01, Dongguan Jietong New Materials Co., Ltd.) were mixed in a mixer, and then injection molded into standard specimens in an injection molding machine.

[0033] The tensile properties of the specimens were tested according to the national standard GB / T 1040.1-2018. The impact properties of the specimens were tested according to GB / T 1043.1-2008. The specimens were placed in an aging box at 120°C for 72 hours, cooled to room temperature, and then tested for tensile and impact properties.

[0034] Table 1

[0035]

[0036]

[0037] The above table shows that compared with Comparative Example 1, when preparing PCT, Examples 1-3 use N-phenylmaleimide diol to replace part of 1,4-cyclohexanedimethanol, thereby introducing flexible ether bonds into the main chain of PCT, and introducing flexible alkyl long chains into the side chains of PCT, showing a good toughening effect, significantly improving the elongation at break and impact strength of PCT. At the same time, the rigid N-phenylmaleimide is introduced into the side chain of PCT to improve its strength and show good tensile strength. In addition, N-phenylmaleimide has high heat resistance, which is beneficial to improving the heat aging resistance of PCT. After high-temperature heat aging treatment, PCT still maintains high tensile strength, elongation at break and impact strength, and the mechanical property retention rate is high.

[0038] In Comparative Example 2, triethylene glycol is used to replace part of 1,4-cyclohexanedimethanol, and flexible ether bonds are introduced into the main chain of PCT. The toughness of PCT is improved, and the elongation at break and impact strength are increased. PCT does not contain flexible long alkyl chains and heat-resistant N-phenylmaleimide, and the elongation at break and impact strength are lower than those of the embodiments. After high-temperature thermal aging treatment, the tensile strength, elongation at break and impact strength of PCT decrease significantly, and the mechanical properties deteriorate.

[0039] The N-phenylmaleimide diol in Comparative Example 3 does not contain an alkyl side chain, has a poor toughening effect, and has a low elongation at break. However, after high-temperature thermal aging treatment, PCT still maintains high tensile strength, elongation at break, and impact strength, and has a high mechanical property retention rate.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high temperature resistant and anti-aging PCT material for LED lamp beads, characterized in that: The preparation method is as follows: add terephthalic acid, 1,4-cyclohexanedimethanol, N-phenylmaleimide diol, and a catalyst into a reaction container equipped with a stirrer and a fractionating column, introduce nitrogen, heat to 240-250° C., react for 2-4 hours, then heat to 270-280° C., react until no water is distilled out, heat to 290-300° C., evacuate, react for 3-4 hours, introduce nitrogen to normal pressure, cool, and discharge to obtain a high temperature resistant and anti-aging PCT material for LED lamp beads; The general structural formula of the N-phenylmaleimide diol is: n is any one of 8-12.

2. The method for preparing the high temperature resistant and anti-aging PCT material for LED lamp beads according to claim 1, characterized in that: The vacuum degree of the vacuum pumping is controlled to be 0.05-0.1 kPa.

3. The method for preparing the high temperature resistant and anti-aging PCT material for LED lamp beads according to claim 1, characterized in that: The ratio of terephthalic acid, 1,4-cyclohexanedimethanol, N-phenylmaleimide diol and catalyst is (80-85) mol: (85-97) mol: (3-15) mol: (0.03-0.04) mol.

4. The method for preparing the high temperature resistant and anti-aging PCT material for LED lamp beads according to claim 3, characterized in that: The catalyst includes tetrabutyl titanate.

5. The method for preparing the high temperature resistant and anti-aging PCT material for LED lamp beads according to claim 3, characterized in that: The preparation method of the N-phenylmaleimide diol is: (1): Add ethanol, ethylene glycol diglycidyl ether, and N-(4-aminophenyl)maleimide to a reaction vessel equipped with a condenser reflux tube and a stirrer, raise the temperature to 45-55° C., react for 5-8 hours, perform vacuum distillation, and separate using a silica gel chromatography column to obtain an intermediate; (2): Add ethanol, intermediate, bromoalkane and sodium carbonate to a reaction vessel equipped with a condenser reflux tube and a stirrer, raise the temperature to 50-65° C., react for 8-12 hours, perform vacuum distillation, and separate using a silica gel chromatography column to obtain N-phenylmaleimide diol.

6. The method for preparing the high temperature resistant and anti-aging PCT material for LED lamp beads according to claim 5, characterized in that: The ratio of ethylene glycol diglycidyl ether to N-(4-aminophenyl)maleimide in (1) is 1 mol:(2.2-2.6) mol.

7. The method for preparing the high temperature resistant and anti-aging PCT material for LED lamp beads according to claim 5, characterized in that: In the above (2), the ratio of the intermediate, alkyl bromide and sodium carbonate is 1 mol:(2-2.6) mol:(2.4-3.2) mol.

8. The method for preparing the high temperature resistant and anti-aging PCT material for LED lamp beads according to claim 7, characterized in that: The molecular formula of the bromoalkane is Br-C n H 2n+1 , n is any one of 8-12.

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