High-temperature-resistant PCTG and preparation method thereof

Abstract

The invention provides high-temperature-resistant PCTG and a preparation method thereof, and belongs to the technical field of synthesis of high polymer materials. The technical problem to be solved by the invention is to provide the preparation method of the high-temperature-resistant PCTG. The method comprises the following steps: (1) esterification reaction: under a protective atmosphere, uniformly mixing phthalic acid, ethylene glycol, a heat-resistant monomer and a catalyst, and reacting at 220-240 DEG C for 2-3 hours; and (2) condensation polymerization: after the esterification reaction is completed, raising the temperature to 260-280 DEG C, controlling the pressure to be 50-300Pa, and reacting for 2.5-3 hours to obtain the high-temperature-resistant PCTG. According to the method, in the preparation process, the conditions of esterification and condensation polymerization are accurately controlled, so that the uniformity of a polymer chain and the suitability of molecular weight are ensured, the PCTG product with high heat resistance and mechanical strength is obtained, and the heat distortion temperature of the PCTG product is up to 89.2 DEG C.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material synthesis, and particularly relates to high-temperature-resistant PCTG and a preparation method thereof. Background Art

[0002] With the improvement of environmental awareness and the emphasis on sustainable development, high-temperature-resistant PCTG (PCTG stands for polyethylene terephthalate-1,4-cyclohexanedimethanol) as a new type of environmentally friendly material has gradually replaced traditional materials such as PVC and PC in the fields of construction, medical treatment, and industry due to its excellent transparency, chemical resistance, impact resistance, and processability. The heat resistance of PCTG is the key to its application, especially in the fields of food packaging, daily necessities and cosmetics packaging, electronic product accessories, medical devices, and automotive interior parts, which have higher requirements for the heat resistance and hygienic properties of the material. Technological innovation and the growth of market demand have promoted the research and development of high-performance PCTG materials. By improving the polymer structure and optimizing the production process, the key performance indicators of the material, such as transparency, heat resistance, and biocompatibility, have been improved.

[0003] These technological innovations not only enhance the application effect of PCTG in existing fields, but also provide the possibility for expanding new markets. In the food packaging industry, PCTG is widely used in beverage bottles, food can lids, lunch boxes, etc. due to its excellent transparency and hygienic performance; in the field of daily necessities and cosmetics packaging, PCTG is used for high-end skin care product packaging bottles, perfume bottles, etc., to ensure product safety and enhance the appearance; in the field of electronic product accessories, PCTG is used to manufacture mobile phone cases, tablet computer protective cases, etc., showing excellent mechanical properties and weather resistance; in the field of medical devices, PCTG is used for components of non-implantable medical devices, such as surgical instrument handles, infusion pump housings, etc., to ensure the safety and durability of medical devices; in the field of automotive interior parts, PCTG is used as a lightweight material to make dashboards, control panels, etc., which are both beautiful and practical. Therefore, the background of studying high-temperature-resistant PCTG is that it can provide higher-performance material solutions to meet the needs of diverse industrial applications while meeting increasingly stringent environmental protection requirements. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing high-temperature-resistant PCTG, and the prepared PCTG is resistant to high temperatures.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a method for preparing high-temperature-resistant PCTG, comprising the following steps:

[0007] (1) Esterification reaction: Under a protective atmosphere, phthalic acid, ethylene glycol, heat-resistant monomer and catalyst are mixed and reacted at 220-240°C for 2-3 hours;

[0008] (2) Polycondensation reaction: After the esterification reaction is completed, the temperature is raised to 260-280°C, the pressure is controlled at 50-300 Pa, and the reaction is carried out for 2.5-3 hours to obtain high temperature resistant PCTG;

[0009] The heat-resistant monomer is at least one of the compounds represented by the structural formula (I) or formula (II):

[0010]

[0011] Wherein, R1, R2, R3 and R4 are all -(CH2) n -OH, n≥0, n is an integer.

[0012] In a specific embodiment, the protective atmosphere is one of nitrogen, helium, argon and neon. Preferably, the protective atmosphere is nitrogen.

[0013] In a specific embodiment, the molar ratio of terephthalic acid to diol is 1:1.2-1.5; in the diol, the molar ratio of ethylene glycol to the heat-resistant monomer is: 1-3:7-9; preferably, in the diol, the molar ratio of ethylene glycol to the heat-resistant monomer is: 1-2:8-9.

[0014] In a specific embodiment, the heat-resistant monomer is a mixture of a heat-resistant monomer I and a heat-resistant monomer II, the structural formula of the heat-resistant monomer I is a compound in which all n are 0, and the structural formula of the heat-resistant monomer II is a compound in which all n are 0.

[0015] In a specific embodiment, the heat-resistant monomer is a mixture of 1,2-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol or 4,4'-bicyclohexanol.

[0016] In a specific embodiment, in the diol, the molar ratio of ethylene glycol, 1,2-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol or 4,4'-bicyclohexanol is 10-20:75:5-15.

[0017] In a specific embodiment, the heat-resistant monomer is a mixture of 1,2-cyclohexanedimethanol and 1,4-cyclohexanediol.

[0018] In a specific embodiment, the molar ratio of terephthalic acid to diol is 1:1.2, and the molar ratio of ethylene glycol, 1,2-cyclohexanedimethanol, and 1,4-cyclohexanediol in the diol is 10:75:15.

[0019] In a specific embodiment, the catalyst is at least one of antimony trioxide, antimony acetate, antimony glycolate, tetrabutyl titanate, tetraisopropyl titanate, stannous chloride or stannous oxide.

[0020] In a specific embodiment, the amount of the catalyst used is 1 to 2‰ of the molar amount of terephthalic acid.

[0021] In one embodiment, pressure relief and drainage are required during the esterification reaction.

[0022] The present invention also provides high-temperature-resistant PCTG prepared by the above preparation method.

[0023] During the preparation process, the present invention ensures the uniformity of the polymer chain and the suitability of the molecular weight by precisely controlling the conditions of the esterification and polycondensation reactions, thereby obtaining a PCTG product with high heat resistance and mechanical strength. The heat deformation temperature (0.45 MPa) of the PCTG product is as high as 89.2°C.

[0024] The high temperature resistant PCTG material has a wide range of applications, including but not limited to food packaging, medical devices, automotive parts and electronic and electrical fields.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention provides a new structure of high temperature resistant PCTG;

[0027] (2) The present invention provides a method for preparing a novel high-temperature resistant PCTG. The prepared high-temperature resistant PCTG can broaden the application of PCTG and has a good market prospect. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing high-temperature-resistant PCTG, comprising the following steps:

[0029] (1) Esterification reaction: Under a protective atmosphere, phthalic acid, ethylene glycol, heat-resistant monomer and catalyst are mixed and reacted at 220-240°C for 2-3 hours;

[0030] (2) Polycondensation reaction: After the esterification reaction is completed, the temperature is raised to 260-280°C, the pressure is controlled at 50-300 Pa, and the reaction is carried out for 2.5-3 hours to obtain high temperature resistant PCTG;

[0031] The heat-resistant monomer is at least one of the compounds represented by the structural formula (I) or formula (II):

[0032]

[0033] Wherein, R1, R2, R3 and R4 are all -(CH2) n-OH, n≥0, n is an integer.

[0034] In one embodiment of the present invention, the protective atmosphere is one of nitrogen, helium, argon and neon. Preferably, the protective atmosphere is nitrogen.

[0035] In a specific embodiment, the molar ratio of terephthalic acid to diol is 1:1.2-1.5; in the diol, the molar ratio of ethylene glycol to the heat-resistant monomer is: 1-3:7-9; preferably, in the diol, the molar ratio of ethylene glycol to the heat-resistant monomer is: 1-2:8-9.

[0036] In the present invention, if the content of the heat-resistant monomer is too high and the content of ethylene glycol is too low, it is difficult to carry out the esterification reaction; if the content of the heat-resistant monomer is too low, the heat-resistant effect of the prepared PCTG is not obvious.

[0037] In a specific embodiment, the heat-resistant monomer is a mixture of a heat-resistant monomer I and a heat-resistant monomer II, the structural formula of the heat-resistant monomer I is a compound in which all n are 0, and the structural formula of the heat-resistant monomer II is a compound in which all n are 0.

[0038] The structural formula of the heat-resistant monomer I is a compound in which all n are 0, that is, when the structural formula of the heat-resistant monomer I is formula (I), R1 and R2 are both -OH; when the structural formula of the heat-resistant monomer I is formula (II), R3 and R4 are both -OH.

[0039] The structural formula of the heat-resistant monomer II is a compound in which n is not all 0, that is, when the structural formula of the heat-resistant monomer II is formula (I), at least one of R1 and R2 is not -OH; when the structural formula of the heat-resistant monomer II is formula (II), at least one of R3 and R4 is not -OH.

[0040] In a specific embodiment, the heat-resistant monomer is a mixture of 1,2-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol or 4,4'-bicyclohexanol.

[0041] In a specific embodiment, in the diol, the molar ratio of ethylene glycol, 1,2-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol or 4,4'-bicyclohexanol is 10-20:75:5-15.

[0042] In a specific embodiment, the heat-resistant monomer is a mixture of 1,2-cyclohexanedimethanol and 1,4-cyclohexanediol.

[0043] In a specific embodiment, the molar ratio of terephthalic acid to diol is 1:1.2, and the molar ratio of ethylene glycol, 1,2-cyclohexanedimethanol, and 1,4-cyclohexanediol in the diol is 10:75:15.

[0044] In a specific embodiment, the catalyst is at least one of antimony trioxide, antimony acetate, antimony glycolate, tetrabutyl titanate, tetraisopropyl titanate, stannous chloride or stannous oxide.

[0045] In a specific embodiment, the amount of the catalyst used is 1 to 2‰ of the molar amount of terephthalic acid.

[0046] In one embodiment, pressure relief and drainage are required during the esterification reaction.

[0047] The present invention also provides high-temperature-resistant PCTG prepared by the above preparation method.

[0048] In the preparation process, the present invention ensures the uniformity of the polymer chain and the suitability of the molecular weight by precisely controlling the conditions of the esterification and polycondensation reactions, thereby obtaining a PCTG product with high heat resistance and mechanical strength, and the heat deformation temperature (0.45MPa) of the PCTG product is as high as 89.2° C. The PCTG product prepared by the present invention improves heat resistance while having no effect on light transmittance and mechanical properties.

[0049] The high temperature resistant PCTG material has a wide range of applications, including but not limited to food packaging, medical devices, automotive parts and electronic and electrical fields.

[0050] The present invention is further described below with specific examples, but the embodiments of the present invention are not limited thereto.

[0051] Example 1 Preparation of High Temperature Resistant PCTG

[0052] In a nitrogen atmosphere, 332.26 g of terephthalic acid, 29.79 g of ethylene glycol, 259.58 g of 1,2-cyclohexanedimethanol, 13.93 g of 1,4-cyclohexanediol, and 0.4 g of catalyst SnO were added to a reaction system equipped with a stirrer, a thermometer, a water separator, and a spherical condenser, followed by nitrogen replacement. After the replacement, the mixture was heated to 230° C. to start the esterification reaction. The pressure was controlled at about 0.3 MPa and the water was continuously discharged. The esterification reaction lasted for 3 hours, and the esterification reaction was completed.

[0053] After the esterification reaction is completed, the temperature is raised to 280°C and the negative pressure is reduced to less than 300 Pa. Under this condition, polycondensation is carried out for 2.5 to 3 hours to obtain high temperature resistant PCTG1.

[0054] Example 2 Preparation of High Temperature Resistant PCTG

[0055] In a nitrogen atmosphere, 332.26 g of terephthalic acid, 22.35 g of ethylene glycol, 259.58 g of 1,2-cyclohexanedimethanol, 27.88 g of 1,4-cyclohexanediol, and 0.4 g of catalyst SnO were added to a reaction system equipped with a stirrer, a thermometer, a water separator, and a spherical condenser, followed by nitrogen replacement. After the replacement, the mixture was heated to 230° C. to start the esterification reaction. The pressure was controlled at about 0.3 MPa and the water was continuously discharged. The esterification reaction lasted for 3 hours, and the esterification reaction was completed.

[0056] After the esterification reaction is completed, the temperature is raised to 280°C and the negative pressure is reduced to less than 300 Pa. Under this condition, polycondensation is carried out for 2.5 to 3 hours to obtain high temperature resistant PCTG2.

[0057] Example 3 Preparation of High Temperature Resistant PCTG

[0058] In a nitrogen atmosphere, 332.26 g of terephthalic acid, 14.9 g of ethylene glycol, 259.58 g of 1,2-cyclohexanedimethanol, 41.82 g of 1,4-cyclohexanediol, and 0.4 g of catalyst SnO were added to a reaction system equipped with a stirrer, a thermometer, a water separator, and a spherical condenser, followed by nitrogen replacement. After the replacement, the mixture was heated to 230° C. to start the esterification reaction. The pressure was controlled at about 0.3 MPa and the water was continuously discharged. The esterification reaction lasted for 3 h, and the esterification reaction was completed.

[0059] After the esterification reaction is completed, the temperature is raised to 280°C and the negative pressure is reduced to less than 300 Pa. Under this condition, polycondensation is carried out for 2.5 to 3 hours to obtain high temperature resistant PCTG3.

[0060] Comparative Example 1

[0061] In a nitrogen atmosphere, 332.26 g of terephthalic acid, 37.24 g of ethylene glycol, 259.58 g of 1,2-cyclohexanedimethanol, and 0.4 g of catalyst SnO were added to a reaction system equipped with a stirrer, a thermometer, a water separator, and a spherical condenser, followed by nitrogen replacement. After the replacement, the system was heated to 230° C. to start the esterification reaction. The pressure was controlled at about 0.3 MPa and the water was continuously discharged. The esterification reaction lasted for 3 hours, and the esterification reaction was completed.

[0062] After the esterification reaction is completed, the temperature is raised to 280°C and the negative pressure is reduced to less than 300 Pa. Under this condition, polycondensation is carried out for 2.5 to 3 hours to obtain high temperature resistant PCTG.

[0063] The molar ratio results of the diols in the raw materials of Examples 1-3 and Comparative Example PCTG are shown in the following table:

[0064] Example Ethylene glycol:1,2-cyclohexanedimethanol:1,4-cyclohexanediol Example 1 20:75:5 Example 2 15:75:10 Example 3 10:75:15 Comparative Example 1 25:75:0

[0065] The glass transition temperatures of PCTG in Examples 1-3 and the comparative examples were tested by DSC at a heating rate of 10°C / min under a nitrogen atmosphere. The results are shown in the following table:

[0066]

[0067]

[0068] The thermal deformation tests of PCTG and comparative examples 1-3 were conducted according to GBT 1634-2004 standard, and the results are shown in the following table:

[0069] Sample name Heat deformation temperature (0.45MPa) / ℃ PCTG1 82.6 PCTG2 86.3 PCTG3 89.2 PCTG 75.5

[0070] The light transmittance results of Examples 1-3 PCTG and Comparative Examples are shown in the following table:

[0071] Sample name Light transmittance / % PCTG1 90.6 PCTG2 91.1 PCTG3 90.3 PCTG 90.5

[0072] The tensile strength and elongation at break of PCTG and the comparative examples are shown in the following table:

[0073] Sample name Tensile strength / MPa Elongation at break / % PCTG1 48.2 143 PCTG2 49.6 125 PCTG3 50.4 102 PCTG 47.3 148

[0074] The tensile strength and elongation at break were tested according to GB / T 1040-92.

[0075] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, wherein the heat-resistant monomer includes 1,2-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol or 4,4'-bicyclohexanol, but is not limited to the monomers provided above, and therefore it cannot be understood as a limitation on the scope of the invention patent.

Claims

1. The preparation method of high temperature resistant PCTG is characterized in that, The steps include: (1) Esterification reaction: Under a protective atmosphere, phthalic acid, ethylene glycol, heat-resistant monomer and catalyst are mixed and reacted at 220-240°C for 2-3 hours; (2) Polycondensation reaction: After the esterification reaction is completed, the temperature is raised to 260-280°C, the pressure is controlled at 50-300 Pa, and the reaction is carried out for 2.5-3 hours to obtain high temperature resistant PCTG; The heat-resistant monomer is at least one of the compounds represented by the structural formula (I) or formula (II): Wherein, R1, R2, R3 and R4 are all -(CH2) n -OH, n≥0, n is an integer.

2. The preparation method of high temperature resistant PCTG according to claim 1, characterized in that, The molar ratio of terephthalic acid to diol is 1:1.2-1.5; in the diol, the molar ratio of ethylene glycol to the heat-resistant monomer is 1-3:7-9; preferably, in the diol, the molar ratio of ethylene glycol to the heat-resistant monomer is 1-2:8-9.

3. The preparation method of high temperature resistant PCTG according to claim 1, characterized in that, The heat-resistant monomer is a mixture of a heat-resistant monomer I and a heat-resistant monomer II. The structural formula of the heat-resistant monomer I is a compound in which all n are 0, and the structural formula of the heat-resistant monomer II is a compound in which all n are 0.

4. The preparation method of high temperature resistant PCTG according to claim 3, characterized in that, The heat-resistant monomer is a mixture of 1,2-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol or 4,4'-bicyclohexanol.

5. The preparation method of high temperature resistant PCTG according to claim 4, characterized in that, In the diol, the molar ratio of ethylene glycol, 1,2-cyclohexanedimethanol or 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol or 4,4'-bicyclohexanol is 10-20:75:5-15.

6. The preparation method of high temperature resistant PCTG according to claim 4, characterized in that, The heat-resistant monomer is a mixture of 1,2-cyclohexanedimethanol and 1,4-cyclohexanediol.

7. The preparation method of high temperature resistant PCTG according to claim 6, characterized in that, The molar ratio of terephthalic acid to diol is 1:1.2, and the molar ratio of ethylene glycol, 1,2-cyclohexanedimethanol, and 1,4-cyclohexanediol in the diol is 10:75:

15.

8. The preparation method of high temperature resistant PCTG according to claim 1, characterized in that, The catalyst is at least one of antimony trioxide, antimony acetate, antimony glycolate, tetrabutyl titanate, tetraisopropyl titanate, stannous chloride or stannous oxide.

9. The preparation method of high temperature resistant PCTG according to claim 1, characterized in that, The amount of the catalyst used is 1 to 2‰ of the molar amount of terephthalic acid.

10. High temperature resistant PCTG, characterized in that, The invention is prepared by the preparation method according to any one of claims 1 to 9.

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