High-transparency glycol modified copolyester material and preparation method thereof

Abstract

The invention discloses a high-transparency glycol modified copolyester material and a preparation method thereof, the high-transparency glycol modified copolyester material is prepared by esterification reaction and polymerization reaction of raw material components including terephthalic acid, ethylene glycol, neopentyl glycol, a catalyst, a phosphoric acid stabilizer and a toner, and the catalyst is at least one of a germanium-based catalyst, an antimony-based catalyst and a titanium-based catalyst. According to the present invention, the color is good, the light transmittance and the haze of the polyester sheet manufactured by using an injection molding machine are equivalent to the light transmittance and the haze of polymethyl methacrylate (PMMA), the requirements for manufacturing various high-grade transparent containers or articles are met, and the impact strength and the chemical resistance are far superior to the PMMA.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester materials, and particularly relates to a high-transparency diol-modified copolyester material and a preparation method thereof. Background Art

[0002] Since the invention of polyethylene terephthalate (PET), the industry has been studying how to change its crystallinity, and thus its physical and chemical properties and post-processing properties, by copolymerizing it with other diacids or diols. Among the commercialized products, the modification is mainly done by copolymerizing terephthalic acid and ethylene glycol with isophthalic acid (IPA), 1,4-cyclohexanedimethanol (CHDM) or neopentyl glycol (NPG). IPA is commonly used in the manufacture of polyester bottles and low-melting cotton and has become a bulk commodity. CHDM is used to modify PET to make PETG and PCTG. These products have very high impact strength and a transparent appearance, as well as good post-processing properties, and are very excellent modified polyesters. Eastman and South Korea's SK have launched a variety of products on the market. However, the production and supply of CHDM are mainly controlled by these two companies, and the price is very expensive, making it difficult for other manufacturers to compete with them when manufacturing PETG with CHDM modification.

[0003] On the other hand, the performance of NPG-modified polyester is similar to that of CHDM-modified polyester in some applications, and NPG is a bulk commodity, easily available and reasonably priced. Therefore, in recent years, many domestic manufacturers have begun to use NPG-modified polyester to manufacture PETG. However, due to its poor color, it can usually only be used in high-shrinkage films or sheets with low appearance requirements. Summary of the invention

[0004] The present invention aims to overcome the defects of the prior art and provide a highly transparent diol-modified copolyester material.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned high-transparency diol-modified copolyester material.

[0006] A highly transparent diol-modified copolyester material is prepared by esterification and polymerization of raw material components including terephthalic acid, ethylene glycol, neopentyl glycol, a catalyst, a phosphoric acid stabilizer and a toner, wherein:

[0007] The catalyst is at least one of a germanium-based catalyst, an antimony-based catalyst and a titanium-based catalyst.

[0008] The mass ratio of terephthalic acid, ethylene glycol and neopentyl glycol is 82-84:27-36:13-19;

[0009] The amount of catalyst added is 50-500ppm.

[0010] In a preferred embodiment of the present invention, the phosphoric acid stabilizer is phosphoric acid or trimethyl phosphate.

[0011] In a preferred embodiment of the present invention, the toner comprises cobalt acetate, blue color oil, red color oil and purple color oil.

[0012] In a preferred embodiment of the present invention, the germanium-based catalyst is germanium dioxide.

[0013] In a preferred embodiment of the present invention, the antimony-based catalyst is ethylene glycol antimony.

[0014] In a preferred embodiment of the present invention, the titanium-based catalyst is AC422 titanium catalyst.

[0015] In a preferred embodiment of the present invention, the germanium-based catalyst is germanium dioxide, the antimony-based catalyst is antimony glycolate, and the titanium-based catalyst is AC422 titanium catalyst.

[0016] Further preferably, the phosphoric acid stabilizer is phosphoric acid or trimethyl phosphate, and the colorant includes cobalt acetate, blue oil, red oil and purple oil.

[0017] The preparation method of the above-mentioned high-transparency diol-modified copolyester material, the specific parameters of the esterification reaction are: nitrogen pressurized to 2kg / cm 2 , the temperature is 220-255°C, the time is 230-240min, and the esterification reaction is carried out until the top temperature of the esterification tower is less than 70°C.

[0018] In a preferred embodiment of the present invention, the specific parameters of the polymerization reaction are: vacuum degree of 70-80 Pa, temperature of 255-285° C., time of 100-105 min, and the polymerization reaction is carried out until the intrinsic viscosity reaches 0.692-0.815.

[0019] The technical solution of the present invention is as follows:

[0020] The beneficial effects of the present invention are as follows: the color of the present invention is good, and the light transmittance and haze of the polyester sheet made by an injection molding machine are analyzed to be equivalent to those of polymethyl methacrylate (PMMA), meeting the requirements for manufacturing various high-end transparent containers or products, and the impact strength and chemical resistance are far superior to those of PMMA. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0022] In the following embodiments: PTA is specifically CAS#: 100-21-0, EG is specifically CAS#: 107-21-1, and neopentyl glycol is specifically CAS#: 126-30-7.

[0023] Example 1

[0024] This embodiment is carried out in a 30-liter polyester pilot plant and comprises the following steps:

[0025] (1) PTA 8300g, EG 2720g, neopentyl glycol 1900g, and germanium dioxide 2.6g were placed in a reaction kettle in sequence, stirred evenly, and then pressurized to 2kg / cm with nitrogen. 2 Then the temperature is raised to 220°C, the reaction starts at about 220°C, and the temperature is gradually raised from 220°C to 255°C for esterification reaction for 240 minutes, until the top temperature of the esterification tower is less than 70°C, and the esterification is completed;

[0026] (2) After adding 1.23 g of phosphoric acid and an appropriate amount of toner (selected from cobalt acetate, blue oil, red oil and purple oil) into the above reaction kettle, continue stirring and evacuate to 75 Pa, then gradually increase the temperature to 255° C., and then gradually increase the temperature to 285° C. while maintaining a vacuum degree of 75 Pa, and carry out polymerization reaction for 100 min until the intrinsic viscosity reaches 0.773, and then stop the reaction;

[0027] (3) Open the valve and transport the material obtained in step (2) to the pelletizer to form slices.

[0028] The obtained slices were analyzed for glass transition temperature (Tg) by differential scanning calorimeter (DSC), their intrinsic viscosity (IV) by Ubbelohde viscometer, and their brightness and color (L, a, b) by spectrophotometer. Some of the obtained slices were made into thin sheets by injection molding machine, and the transmittance and haze were measured by transmittance haze meter. The above data are listed in Table 1 for comparison.

[0029] Example 2

[0030] This embodiment is carried out in a 30-liter polyester pilot plant and comprises the following steps:

[0031] (1) PTA 8300g, EG 3130g, neopentyl glycol 1300g and toner (selected from cobalt acetate, blue oil, red oil and purple oil) were placed in a reaction kettle in sequence, stirred evenly and pressurized with nitrogen to 2kg / cm 2 Then the temperature is raised to 220°C, the reaction starts at about 220°C, and the temperature is gradually raised from 220°C to 255°C for esterification reaction for 240 minutes, until the top temperature of the esterification tower is less than 70°C, and the esterification is completed;

[0032] (2) After adding 1.47 g of germanium dioxide, 1.78 g of antimony glycol and 1.23 g of an appropriate amount of phosphoric acid into the above reaction kettle, stirring was continued and the mixture was evacuated to 75 Pa, and then the temperature was gradually raised to 255° C., and then the temperature was gradually raised to 285° C. while maintaining a vacuum degree of 75 Pa, and the polymerization reaction was carried out for 100 min. When the viscosity reached 0.746, the reaction was stopped;

[0033] (3) Open the valve and transport the material obtained in step (2) to the pelletizer to form slices.

[0034] The obtained slices were analyzed for glass transition temperature (Tg) by differential scanning calorimeter (DSC), their intrinsic viscosity (IV) by Ubbelohde viscometer, and their brightness and color (L, a, b) by spectrophotometer. Some of the obtained slices were made into thin sheets by injection molding machine, and the transmittance and haze were measured by transmittance haze meter. The above data are listed in Table 1 for comparison.

[0035] Example 3

[0036] This embodiment is carried out in a 30-liter polyester pilot plant and comprises the following steps:

[0037] (1) PTA 8300g, EG 3600g, and neopentyl glycol 1300g were placed in the reactor in sequence, stirred evenly, and then pressurized to 2kg / cm with nitrogen. 2 Then the temperature is raised to 220°C, the reaction starts at about 220°C, and the temperature is gradually raised from 220°C to 255°C for esterification reaction for 240 minutes, until the top temperature of the esterification tower is less than 70°C, and the esterification is completed;

[0038] (2) After adding 3.56 g of ethylene glycol antimony and 0.338 g of trimethyl phosphate into the above reaction kettle, stirring was continued and the vacuum was evacuated to 75 Pa, and then the temperature was gradually raised to 255° C., and then the temperature was gradually raised to 285° C. while maintaining a vacuum degree of 75 Pa, and the polymerization reaction was carried out for 105 min until the intrinsic viscosity reached 0.815, and the reaction was stopped;

[0039] (3) Open the valve and transport the material obtained in step (2) to the pelletizer to form slices.

[0040] The obtained slices were analyzed for glass transition temperature (Tg) by differential scanning calorimeter (DSC), their intrinsic viscosity (IV) by Ubbelohde viscometer, and their brightness and color (L, a, b) by spectrophotometer. Some of the obtained slices were made into thin sheets by injection molding machine, and the transmittance and haze were measured by transmittance haze meter. The above data are listed in Table 1 for comparison.

[0041] Example 4

[0042] This embodiment is carried out in a 30-liter polyester pilot plant and comprises the following steps:

[0043] (1) PTA 8300g, EG 3130g, neopentyl glycol 1300g, germanium dioxide 2.6g and toner (selected from cobalt acetate, blue oil, red oil and purple oil) were placed in a reaction kettle in sequence, stirred evenly and pressurized with nitrogen to 2kg / cm 2 Then the temperature is raised to 220°C, the reaction starts at about 220°C, and the temperature is gradually raised from 220°C to 255°C for esterification reaction for 240 minutes, until the top temperature of the esterification tower is less than 70°C, and the esterification is completed;

[0044] (2) After adding 1.21 g of antimony glycol, 5.1 g of AC422 titanium catalyst and 1.547 g of phosphoric acid into the above reaction kettle, stirring was continued and vacuuming was carried out to 75 Pa, then the temperature was gradually raised to 255° C., and then the temperature was gradually raised to 285° C. while maintaining a vacuum degree of 75 Pa, and the polymerization reaction was carried out for 100 min until the intrinsic viscosity reached 0.692, and the reaction was stopped;

[0045] (3) Open the valve and transport the material obtained in step (2) to the pelletizer to form slices.

[0046] The obtained slices were analyzed for glass transition temperature (Tg) by differential scanning calorimeter (DSC), their intrinsic viscosity (IV) by Ubbelohde viscometer, and their brightness and color (L, a, b) by spectrophotometer. Some of the obtained slices were made into thin sheets by injection molding machine, and the transmittance and haze were measured by transmittance haze meter. The above data are listed in Table 1 for comparison.

[0047] Table 1

[0048] Example 1. Example 2 Example 3 Example 4 PMMA Catalytic Metals germanium Germanium / Antimony antimony Germanium / Antimony / Titanium No comparison IV 0.773 0.746 0.815 0.692 No comparison Tg 74 73 73 73 110-120 L 53.5 53.6 49 52.8 >50 a 0.5 0.8 0.6 0.9 <3 b -2.6 -1.8 -0.4 -2.6 <0.3 Light transmittance 90 85 80 85 90-93 Haze 0.2 1.0 1.5 1.1 <2％

[0049] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A highly transparent diol-modified copolyester material, characterized in that: The invention is prepared by esterification and polymerization of raw material components including terephthalic acid, ethylene glycol, neopentyl glycol, catalyst, phosphoric acid stabilizer and toner, wherein: The catalyst is at least one of a germanium-based catalyst, an antimony-based catalyst and a titanium-based catalyst. The mass ratio of terephthalic acid, ethylene glycol and neopentyl glycol is 82-84:27-36:13-19; The amount of catalyst added is 50-500ppm.

2. A highly transparent diol-modified copolyester material as claimed in claim 1, characterized in that: The phosphoric acid stabilizer is phosphoric acid or trimethyl phosphate.

3. A highly transparent diol-modified copolyester material as claimed in claim 1, characterized in that: The toner includes cobalt acetate, blue oil, red oil and purple oil.

4. A highly transparent diol-modified copolyester material as claimed in claim 1, characterized in that: The germanium-based catalyst is germanium dioxide.

5. The high-transparency diol-modified copolyester material according to claim 1, characterized in that: The antimony-based catalyst is ethylene glycol antimony.

6. A highly transparent diol-modified copolyester material according to claim 1, characterized in that: The titanium-based catalyst is AC422 titanium catalyst.

7. A highly transparent diol-modified copolyester material as claimed in claim 1, characterized in that: The germanium-based catalyst is germanium dioxide, the antimony-based catalyst is ethylene glycol antimony, and the titanium-based catalyst is AC422 titanium catalyst.

8. A highly transparent diol-modified copolyester material as claimed in claim 7, characterized in that: The phosphoric acid stabilizer is phosphoric acid or trimethyl phosphate, and the toner includes cobalt acetate, blue oil, red oil and purple oil.

9. The method for preparing a highly transparent diol-modified copolyester material according to any one of claims 1 to 7, characterized in that: The specific parameters of the esterification reaction are: nitrogen pressurized to 2kg / cm 2 , the temperature is 220-255°C, the time is 230-240min, and the esterification reaction is carried out until the top temperature of the esterification tower is less than 70°C.

10. The preparation method according to claim 9, characterized in that: The specific parameters of the polymerization reaction are: vacuum degree of 70-80 Pa, temperature of 255-285° C., time of 100-105 min, and the polymerization reaction is carried out until the intrinsic viscosity reaches 0.692-0.815.