A method of producing a polyester pellet

Abstract

A method of producing a polyester pellet comprising the following steps: (a). a solution to be esterified is subjected to esterification reaction to obtain an esterified product, the solution to be esterified comprising terephthalic acid, ethylene glycol and amino-containing monomer, the amino-containing monomer is water-soluble chitosan or N-(2-hydroxyethyl)piperazine; (b).a solution to be polymerized is subjected to polymerization reaction to obtain a polyester product, the solution to be polymerized comprising catalyst and the esterified product; and(c). the polyester product is pelletized to obtain a polyester pellet, when the amino-containing monomer is the water-soluble chitosan, the weight ratio of the amino-containing monomer to the polyester pellet is in the range of

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a polymer material, and more particularly to a method for manufacturing polyester particles. [Previous Technology]

[0002] Polyester materials that are both printable and antibacterial have important applications in many fields. For example, polyester materials can be made into food packaging films for packaging food. Not only can food labels or patterns be printed on the food packaging film, but the packaged food can also be made less prone to spoilage, thereby extending the shelf life of the food.

[0003] Most polyester materials used to make food packaging films are made by bonding a printable polyester outer layer with an antibacterial non-polyester inner layer. The printable polyester outer layer is obtained by polarizing the polyester film. However, there is currently no technology that can produce a polyester material that is integrally molded and has both printability and antibacterial properties. [Summary of the Invention]

[0004] Therefore, the object of the present invention is to provide an innovative method for manufacturing polyester pellets.

[0005] Therefore, the method for manufacturing polyester pellets of the present invention includes a step (a), a step (b) and a step (c).

[0006] Step (a) involves subjecting a solution containing terephthalic acid, ethylene glycol, and an amine-containing monomer to an esterification reaction to obtain an esterified product. The amine-containing monomer is either water-soluble chitosan or N-(hydroxyethyl)piperazine.

[0007] Step (b) involves polymerizing the liquid to be polymerized, which contains the catalyst and the esterified compound, to obtain a polyester.

[0008] Step (c) is to granulate the polyester to obtain polyester granules.

[0009] When the amino-containing monomer is the water-soluble chitosan, the weight ratio of the amino-containing monomer to the polyester particle is 0.01 or more and less than 0.15; when the amino-containing monomer is the N-(hydroxyethyl)piperazine, the weight ratio of the amino-containing monomer to the polyester particle is 0.05 or more and less than 0.75.

[0010] The advantage of the present invention is that, through the type of the amine-containing monomer and the range of its weight ratio with the polyester granules, the polyester granules obtained have both printability and antibacterial properties.

Implementation Method

[0011] The method for manufacturing polyester granules of the present invention includes steps (a) subjecting an esterification solution to an esterification reaction to obtain an esterified product, (b) subjecting a polymerization solution containing the esterified product to a polymerization reaction to obtain a polyester product, and (c) granulating the polyester product to obtain polyester granules. Each step is described in detail below.

[0012] [Step (a)]

[0013] The esterification solution contains terephthalic acid, ethylene glycol and an amine-containing monomer, wherein the amine-containing monomer is water-soluble chitosan or N-(hydroxyethyl)piperazine.

[0014] In some embodiments of the present invention, the amount of ethylene glycol ranges from 27.6 parts by weight to 46.5 parts by weight, based on 100 parts by weight of terephthalic acid, so that the obtained ester has a better yield.

[0015] The weight-average molecular weight (Mw) of chitosan affects its solubility in water. For example, chitosans with a weight-average molecular weight of 50 kDa or higher are poorly soluble in water and are classified as fat-soluble chitosans; chitosans with a weight-average molecular weight of less than 50 kDa are readily soluble in water and are classified as water-soluble chitosans. If fat-soluble chitosans are used as the amine-containing monomer, the amine-containing monomer is difficult to dissolve in ethylene glycol and exists in solid form in ethylene glycol. During the esterification reaction, the amine-containing monomer carbonizes and turns black due to heat. This invention uses water-soluble chitosans as the amine-containing monomer, which can be dissolved in ethylene glycol to form a homogeneous esterification solution. In some embodiments of this invention, the weight-average molecular weight of the water-soluble chitosan ranges from 20 kDa to 40 kDa.

[0016] When the amino-containing monomer is the water-soluble chitosan, in some embodiments of the present invention, based on 100 parts by weight of terephthalic acid, the amount of the amino-containing monomer ranges from 0.01 parts by weight to less than 0.12 parts by weight.

[0017] When the amino-containing monomer is N-(hydroxyethyl)piperazine, in some embodiments of the present invention, the amount of the amino-containing monomer is 0.06 parts by weight or more and less than 0.58 parts by weight, based on 100 parts by weight of terephthalic acid.

[0018] In some embodiments of the present invention, the esterification solution further comprises a crystallization inhibitor. The function of the crystallization inhibitor is to reduce the crystallinity of the polyester obtained in step (b), thereby giving the polyester better processability in subsequent applications. For example, the polyester, due to its low crystallinity, can be processed into a shrinkable film. The type of crystallization inhibitor is not limited; for example, the crystallization inhibitor is selected from at least one of 1,2-propanediol and 2-methyl-1,3-propanediol.

[0019] When the crystallization inhibitor is 1,2-propanediol, in some embodiments of the present invention, the amount of the crystallization inhibitor is greater than 0 parts by weight and less than 3.1 parts by weight, based on 100 parts by weight of terephthalic acid, so that the obtained esterified product has a better yield and the obtained polyester product has better processability.

[0020] When the crystallization inhibitor is 2-methyl-1,3-propanediol, in some embodiments of the present invention, the amount of the crystallization inhibitor is greater than 0 parts by weight and less than 23.5 parts by weight, based on 100 parts by weight of terephthalic acid, so that the obtained esterified product has a better yield and the obtained polyester product has better processability.

[0021] When the crystallization inhibitor is 1,2-propanediol and 2-methyl-1,3-propanediol, in some embodiments of the present invention, based on 100 parts by weight of terephthalic acid, the amount of the crystallization inhibitor ranges from greater than 0 parts by weight to less than 26.6 parts by weight, resulting in a better yield of the esterified compound and better processability of the obtained polyester. In some embodiments of the present invention, the weight ratio of 1,2-propanediol to 2-methyl-1,3-propanediol is 0.13.

[0022] Those skilled in the art of polyester materials technology can flexibly adjust the temperature and pressure of the esterification reaction as needed. For example, in some embodiments of the present invention, the esterification solution is subjected to an esterification reaction under conditions ranging from 220°C to 240°C and from 1.8 kg / cm² to 2.2 kg / cm².

[0023] [Step (b)]

[0024] The polymerization solution contains a catalyst and the esterified product obtained in step (a). The catalyst serves to promote the polymerization reaction of the esterified product. The type and amount of the catalyst are not particularly limited. For example, the catalyst can be stannous oxalate and antimony glycolate, and the amount of the catalyst can be 1.4 × 10⁻³ parts by weight, based on 100 parts by weight of the total amount of terephthalic acid.

[0025] Those skilled in the art of polyester materials technology can flexibly adjust the temperature and pressure of the polymerization reaction as needed. For example, in some embodiments of the present invention, the polymerization liquid is subjected to a polymerization reaction under conditions ranging from a temperature of 240°C to 250°C and a pressure of 1.4 × 10⁻³ kg / cm² to 2.8 × 10⁻³ kg / cm².

[0026] [Step (c)]

[0027] When the amine-containing monomer is the water-soluble chitosan, the weight ratio of the amine-containing monomer to the polyester particles ranges from 0.01 to less than 0.15. In some embodiments of the present invention, the weight ratio of the amine-containing monomer to the polyester particles ranges from 0.01 to 0.1.

[0028] When the amine-containing monomer is N-(hydroxyethyl)piperazine, the weight ratio of the amine-containing monomer to the polyester particle is in the range of 0.05 or more and less than 0.75. In some embodiments of the present invention, the weight ratio of the amine-containing monomer to the polyester particle is in the range of 0.05 to 0.5.

[0029] By using the type of amine-containing monomer and the range of its weight ratio with the polyester granules, the polyester granules can be successfully produced, and the resulting polyester granules also have printability and antibacterial properties.

[0030] In detail, the amine-containing monomer imparts high polarity to the polyester particle, causing the polyester particle to form hydrogen bonds and covalent bonds with the ink, so that the ink can easily adhere to the surface of the polyester particle and is not easy to fall off the surface of the polyester particle, thus the polyester particle is printable.

[0031] When the polyester particle comes into contact with the negatively charged bacterial cell membrane, the polyester particle containing amine groups will be induced to generate a positive charge and generate an electrostatic interaction with the bacterial cell membrane. This electrostatic interaction will destroy the structure of the bacterial cell membrane, reduce the stability of the bacterial cell membrane, and even inhibit the growth of bacteria. Therefore, the polyester particle has antibacterial properties.

[0032] Those familiar with the technology of polyester materials can flexibly adjust the granulation process parameters according to their needs.

[0033] The polyester granules can subsequently be processed into a polyester film through various procedures such as hot pressing, extrusion, and stretching. In some embodiments of the present invention, the polyester granules are hot-pressed to form an integrally molded polyester film. Because the polyester granules have both printability and antibacterial properties, the polyester film formed from the polyester granules naturally also has both printability and antibacterial properties.

[0034] The present invention will be further described with reference to the following embodiments, but it should be understood that the embodiments are only for illustrative purposes and should not be construed as limiting the implementation of the present invention.

[0035] 〈Example 1〉

[0036] (a). Using water-soluble chitosan as the modifying monomer, 1.5 g of water-soluble chitosan and 720 g of ethylene glycol were added to a reaction vessel and stirred at 60 rpm using a stirrer. Then, 2600 g of terephthalic acid and 691 g of crystallization inhibitor (obtained by mixing 611 g of 2-methyl-1,3-propanediol and 80 g of 1,2-propanediol) were added to the reaction vessel, forming an esterification solution. The temperature of the esterification solution was then raised to 220°C, and nitrogen gas was introduced into the reaction vessel to increase the pressure inside the vessel to 2.0 kg / cm². When the temperature at the top of the reaction vessel was between 125°C and 150°C, it indicated that the esterification reaction had begun. Once the temperature at the top of the reaction tank drops below 125°C, it indicates that the esterification reaction of the solution to be esterified has been completed, yielding 3247.5g of esterified product.

[0037] (b). 3.6g of catalyst (obtained by mixing 2g of stannous oxalate and 1.6g of antimony glycolate) was added to the reaction vessel containing the esterified compound, and stirred at 60rpm for 5 minutes using a stirrer to form a polymerization solution in the reaction vessel. Then, the temperature of the polymerization solution was raised to 247°C, and the pressure inside the reaction vessel was reduced to 2.632×10⁻³ kg / cm². When the stirrer power reached 144W, it indicated that the polymerization reaction of the polymerization solution had begun. When the stirrer power was raised to 250W, the speed of the stirrer was reduced to 45rpm, and then the stirrer power was reduced to below 210W. When the stirrer power returned to 210W, it indicated that the polymerization reaction of the polymerization solution had been completed, and a polyester material with a long strip shape was obtained.

[0038] (c). The polyester is fed to a pelletizer for granulation to obtain 3000g of polyester pellets.

[0039] <Examples 2 to 12 and Comparative Examples 1 to 4>

[0040] The difference between Examples 2 to 12 and Comparative Examples 1 to 4 and Example 1 is that the raw materials used in manufacturing polyester pellets are changed as shown in Table 1.

[0041] Comparative Examples 3 and 4 failed to obtain polyester products successfully during step (b), and therefore did not proceed to step (c) to produce polyester granules. Ignoring the fact that Comparative Examples 3 and 4 actually failed to obtain polyester granules, assuming that Comparative Examples 3 and 4 could also obtain 3000g of polyester granules as expected, the weight ratio of modified monomer to polyester granules in Comparative Examples 3 and 4 was calculated accordingly, and the reasons why Comparative Examples 3 and 4 failed to obtain polyester products successfully were analyzed.

[0042] Information on each raw material in Examples 1 to 12 and Comparative Examples 1 to 4 is as follows. raw material Specific types weight average molecular weight range source Modified monomers Water-soluble chitosan 20kDa to 40kDa Shansheng Biotechnology Co., Ltd. N-(hydroxyethyl)piperazine -- Yuhe Trading Co., Ltd. isophthalic acid -- Tainan Textile Co., Ltd. Ethylene glycol -- Tainan Textile Co., Ltd. terephthalic acid -- Tainan Textile Co., Ltd. crystallization Inhibitors 2-Methyl-1,3-propanediol -- Yong Sheng Trading Co., Ltd. 1,2-Propanediol -- Tainan Textile Co., Ltd. catalyst Stannous oxalate -- Tainan Textile Co., Ltd. Antimony Glycol -- Tainan Textile Co., Ltd. Note: "--" indicates that it is not applicable.

[0043] 〈Evaluation Items〉

[0044] [Printing Adhesion]

[0045] A dye solution (sourced from Yung-Ta Plastic Printing Factory) and a diluent (main component: toluene) were mixed at a volume ratio of 1:1 to obtain a dye. The polyester granules from Example 1 were hot-pressed and cut into a 3cm × 2cm polyester film. The surface of the polyester film was cleaned with ethanol and then dried to obtain a cleaned film. 40μL of the dye solution was evenly applied to one surface of the cleaned film using a scraper. The cleaned film coated with the dye was then left to stand at room temperature (25°C) for 10 minutes to allow the dye to dry and form a dyed layer, resulting in a sample containing both the cleaned film and the dyed layer. A transparent tape was evenly adhered to the dyed layer of the sample. After standing for 1 minute, the transparent tape was removed, and the amount of dyed layer adhered to the transparent tape was observed to evaluate the printing adhesion of the dye to the polyester film. The polyester granules from Examples 2 to 4 and 7 to 10 were also tested for printing adhesion using the same testing procedure described above. The test results are shown in Figure 1.

[0046] [Dyne Value]

[0047] The polyester granules from Example 1 were hot-pressed and then cut into 11 polyester films with a size of 3cm × 3cm. According to the DIN ISO 8296 standard (2003 edition), dyne pens (source: ACCU DYNE TEST) with dyne values ​​of 72, 70, 68, 66, 64, 62, 60, 58, 56, 54 and 52 dyn / cm were used to draw 10cm ink marks on the polyester films respectively and in sequence. That is, a dyne pen with 72 dyn / cm was used to draw on one polyester film, a dyne pen with 70 dyn / cm was used to draw on the next polyester film, and so on. Then the shrinkage phenomenon of the ink mark on each polyester film was observed. In detail, firstly, an ink mark was drawn on one polyester film using a dyne pen with a dyne value of 72 dyn / cm. If more than 90% of the ink mark on the polyester film did not shrink within 2 seconds after being drawn, the dyne value of the polyester film was ≥72 dyn / cm. If more than 90% of the ink mark on the polyester film shrank and formed ink beads within 2 seconds after being drawn, then an ink mark was drawn on another polyester film using a dyne pen with a dyne value of 70 dyn / cm, until the ink mark drawn by the dyne pen no longer shrank. The dyne value of the polyester film at this point is the dyne value of the dyne pen. The polyester particles in Examples 2 to 12, Comparative Examples 1 and 2 were also analyzed for dyne value using the detection procedure described above, and the analysis results are shown in Table 2.

[0048] [Bacterial Adhesion Rate]

[0049] 10g of LB medium (source: Yuhe Trading Co., Ltd.) was completely dissolved in 500mL of deionized water and wet sterilized in an autoclave at 121°C for 20 minutes to obtain sterilized medium.

[0050] 1000 μL of frozen bacterial culture (Escherichia coli; accession number ATCC 8739) and 25 μL of antibiotic (Ampicillin; source: Yuho Trading Co., Ltd.) were added to the sterile culture medium, and then the medium was placed in a shaking incubator and cultured at 37°C and 100 rpm for 18 hours to obtain the cultured bacterial culture. The cultured bacterial culture was centrifuged for 5 minutes at a relative centrifugal force of 3820 g, an acceleration of 9 g / s, and a deceleration of 5 g / s to obtain the first precipitate. The first precipitate was mixed with 20 mL of sterile phosphate buffer solution (PBS; source: Yuho Trading Co., Ltd.) and centrifuged to obtain the second precipitate. The second precipitate was mixed with 20 mL of the sterile phosphate buffer solution and centrifuged to obtain the third precipitate. The third precipitate was mixed with 10 mL of the sterilized phosphate buffer solution to uniformly disperse the third precipitate in the sterilized phosphate buffer solution, resulting in a treated bacterial solution with a bacterial concentration between 8 × 10⁸ cells / mL and 1.2 × 10⁹ cells / mL.

[0051] The polyester granules from Example 1 were hot-pressed and cut into a 1cm × 1cm polyester membrane. The polyester membrane was immersed in 1mL of the sterilized phosphate buffer solution and placed in a hot air circulating oven at 37°C for 12 hours to allow it to swell. It was then rinsed three times with the sterilized phosphate buffer solution to obtain a swollen membrane. The swollen membrane was immersed in 1mL of the treated bacterial solution and placed in the hot air circulating oven at 37°C for 3 hours to allow bacteria to adhere to the surface of the swollen membrane. It was then rinsed three times with the sterilized phosphate buffer solution to obtain a reprocessed membrane. The reprocessed membrane was immersed in 1mL of glutaraldehyde solution (obtained by mixing 2.5wt% glutaraldehyde and 97.5wt% PBS) for 3 hours, allowing glutaraldehyde to not only fix the bacteria but also interact with bacterial proteins to form fluorescent compounds, thereby staining and fixing the bacteria. The membrane was then removed from the glutaraldehyde solution to obtain the membrane to be analyzed.

[0052] The polyester particles of Comparative Example 1 were also used to obtain the membrane to be analyzed in the manner described above.

[0053] The membranes to be analyzed in Example 1 and Comparative Example 1 were analyzed using a scanning electron microscope (SEM; Phenom; Pro). The degree of bacterial adhesion on the surface of the membranes to be analyzed was observed, and the results are shown in Figure 2. The degree of bacterial adhesion on the surface of the membranes to be analyzed was quantified using ImageJ software. The number of bacterial particles attached to the surface of the membrane to be analyzed in Comparative Example 1 was used as the denominator, and the number of bacterial particles attached to the surface of the membrane to be analyzed in Example 1 was used as the numerator. The bacterial adhesion rate of the membrane to be analyzed in Example 1 relative to that in Comparative Example 1 was obtained by dividing the numerator by the denominator (i.e., the bacterial adhesion rate of Comparative Example 1 was taken as 100%). The polyester particles of Examples 2 to 4, 6 to 10, 12 and Comparative Example 2 were also analyzed for bacterial adhesion rate using the detection procedure described above. The analysis results are shown in Table 2.

[0054] [Thermal Decomposition Temperature]

[0055] The polyester particles of Example 1 were analyzed using a thermogravimetric analyzer (TGA; brand: Perkin-Elmer; model: TGA 7). The polyester particles were heated in a nitrogen atmosphere at a temperature range of 30°C to 800°C at a heating rate of 10°C / min to obtain a TGA curve, from which the thermal decomposition temperature of the polyester particles was obtained. The polyester particles of Examples 2 to 12, Comparative Examples 1 and 2 were also analyzed for thermal decomposition temperature using the detection procedure described above, and the analysis results are shown in Table 2.

[0056] [Glass Transfer Temperature]

[0057] The polyester particles of Example 1 were analyzed using a differential scanning calorimeter (DSC; brand: Perkin-Elmer; model: DSC 7). The polyester particles were subjected to staged heating in a nitrogen atmosphere to obtain DSC curves, and the glass transition temperature of the polyester particles was obtained from the DSC curves. The polyester particles of Examples 2 to 12, Comparative Examples 1 and 2 were also analyzed for glass transition temperature using the detection procedure described above, and the analysis results are shown in Table 2.

[0058] The specific operation of this staged heating is as follows: first, the polyester granules are heated from 30°C to 300°C at a heating rate of 20°C / min, then cooled to 30°C at a cooling rate of 10°C / min to release the internal stress of the polyester granules, and then heated from 30°C to 300°C at a heating rate of 10°C / min.

[0059] [Mel volumetric flow rate]

[0060] The polyester granules of Example 1 were analyzed using a melt flow indexer (Cometech; model QC-652S). The polyester granules were melted at 240°C and extruded under a load of 2060g. The volume of the melt extruded within 10 minutes was the melt flow rate of the polyester granules. The polyester granules of Examples 2 to 12, Comparative Examples 1 and 2 were also analyzed for melt flow rate using the detection procedure described above. The analysis results are shown in Table 2.

[0061] [Intrinsic Viscosity]

[0062] Referring to ASTM D 4603-96 standard specification (2018 edition), the polyester granules of Example 1 were dried at 60°C for 24 hours to obtain a dehydrated sample. 0.14 g of this dehydrated sample was mixed with 25 mL of a mixed solvent (obtained by mixing phenol and 1,1,2,2-tetrachloroethane in a weight ratio of 6:4) and stirred at 120°C for 15 to 30 minutes to ensure complete dissolution of the dehydrated sample in the mixed solvent, thus obtaining the analytical solution. The analytical solution was placed in a constant temperature water bath, and the flow time of the analytical solution at 25°C within 0.2 seconds was recorded five times using an Oswald viscometer (brand: RAMIN; model: USA). The average value was then substituted into the Billmeyer equation to obtain the intrinsic viscosity of the polyester granules. The polyester particles of Examples 2 to 12, and Comparative Examples 1 and 2 were also analyzed for intrinsic viscosity using the detection procedure described above, and the results are shown in Table 2.

[0063] Billmeyer equation: [η] = 0.25×[(η relative)-1+3×ln(η relative)] / c, where [η] is the intrinsic viscosity of the solution to be analyzed in Example 1 (in dL / g), c is the concentration of the solution to be analyzed in Example 1 (g / dL), and η relative is the relative viscosity, which is = [(solution viscosity) / (solvent viscosity)] = [(flow time of the solution to be analyzed in Example 1) / (flow time of the mixed solvent)].

[0064] Table 1 PTA (g) EG (g) Crystallization inhibitors Modified monomers Modified monomers With polyester particles weight ratio MPO (g) 1,2-PDO (g) type Dosage (g) Example 1 2600 720 611 80 Water-soluble chitosan 1.5 0.05 2 2600 720 611 80 Water-soluble chitosan 3 0.1 3 2600 720 611 80 Water-soluble chitosan 0.3 0.01 4 2600 720 611 80 Water-soluble chitosan 0.9 0.03 5 2600 786 611 -- Water-soluble chitosan 1.5 0.05 6 2600 1207 -- -- Water-soluble chitosan 1.5 0.05 7 2600 720 611 80 HEP 1.5 0.05 8 2600 720 611 80 HEP 3 0.1 9 2600 720 611 80 HEP 9 0.3 10 2600 720 611 80 HEP 15 0.5 11 2600 786 611 -- HEP 1.5 0.05 12 2600 1207 -- -- HEP 1.5 0.05 Comparative example 1 2510 1260 -- -- isophthalic acid 90 3 2 2600 720 611 80 -- 3 2600 720 611 80 Water-soluble chitosan 4.5 0.15 4 2600 720 611 80 HEP 22.5 0.75 annotation: 1. "PTA" is terephthalic acid; "EG" is ethylene glycol; "MPO" is 2-methyl-1,3-propanediol; "1,2-PDO" is 1,2-propanediol; "HEP" is N-(hydroxyethyl)piperazine. 2. "--" indicates that it is not used.

[0065] Table 2 Dyne value (dyn / cm) Bacterial Adhesion (%) T d (°C) T g (°C) MVR (cm 2 / 10 min) IV (dL / g) Example 1 58 10.48 415.68 60.11 53.52 0.66 2 60 8.57 400.78 66.62 46.20 0.66 3 58 57.14 404.06 66.36 48.92 0.66 4 56 31.43 404.13 66.88 50.06 0.69 5 56 -- 456.47 64.64 45.43 0.60 6 58 12.20 429.73 64.06 47.18 0.65 7 56 30.48 417.42 63.89 54.80 0.71 8 54 15.24 438.36 67.91 41.18 0.59 9 56 7.62 449.05 67.69 77.50 0.63 10 52 4.76 400.01 67.77 58.84 0.64 11 56 -- 414.63 63.98 39.72 0.67 12 60 34.15 461.27 62.60 40.34 0.62 Comparative example 1 54 100 405.67 82.20 25 0.84 2 ≥72 97.56 405.72 65.50 62.40 0.58 annotation: 1. "T" d "T" represents the thermal decomposition temperature; g "" represents the glass transition temperature; "MVR" represents the melt volumetric flow rate; and "IV" represents the intrinsic viscosity. 2. "--" indicates no detection.

[0066] Referring to Figure 1, since the amount of dyed layer adhering to all transparent tapes is small, it indicates that the dyed layer in all samples can be stably adhered to the cleaned film, showing that the polyester granules of Examples 1 to 4 and 7 to 10 have good printing adhesion.

[0067] As shown in Tables 1 and 2, compared to Comparative Example 1, which used isophthalic acid as a modifying monomer, or compared to Comparative Example 2, which did not use any modifying monomer, Examples 1 to 12, because water-soluble chitosan or N-(hydroxyethyl)piperazine was used as a modifying monomer in step (a), all had polyester films with a dyn value of 52 dyn / cm or higher, and the bacterial adhesion rate of the films to be analyzed formed from the polyester particles of Examples 1 to 4, 6 to 10 and 12 was all below 57.14%. Therefore, these polyester films possess both printability and antibacterial properties, and the polyester particles of Examples 1 to 12 naturally also possess the aforementioned dual effects.

[0068] Compared to Comparative Example 3, where polyester could not be obtained, Examples 1 to 6 were able to obtain polyester particles smoothly because the weight ratio of water-soluble chitosan to polyester particles was between 0.01 and 0.15.

[0069] Compared to Comparative Example 4, where polyester could not be obtained, Examples 7 to 12 were able to obtain polyester particles smoothly because the weight ratio of N-(hydroxyethyl)piperazine to polyester particles was between 0.05 and 0.75.

[0070] In summary, the method for manufacturing polyester particles of the present invention uses water-soluble chitosan or N-(hydroxyethyl)piperazine, and combines them with a weight ratio range of polyester particles, so that the polyester particles obtained have both printability and antibacterial properties. The polyester film obtained by hot pressing the polyester particles is integrally formed and has both printability and antibacterial properties, so the purpose of the present invention can be achieved.

[0071] However, the above description is only an embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the patent specification shall still fall within the scope of the patent of the present invention. [Simplified Explanation of the Diagram]

[0072] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the figures, wherein: Figure 1 is a photograph illustrating the test results of the printing adhesion of the polyester particles of Examples 1 to 4 and 7 to 10; and Figure 2 is a SEM image illustrating the observation results of the degree of bacterial adhesion of the polyester particles of Examples 1 to 4, 6 to 10, 12, and Comparative Examples 1 and 2.

Claims

1. A method for manufacturing polyester particles, comprising the following steps: (a) subjecting an esterification reaction to an esterification solution containing terephthalic acid, ethylene glycol, and an amine-containing monomer to obtain an esterified product, wherein, The amine-containing monomer is a water-soluble chitosan or N-(hydroxyethyl)piperazine, wherein the weight-average molecular weight of the water-soluble chitosan is in the range of 20 kDa to 40 kDa; (b) a polymerization reaction is carried out on a polymerizable liquid containing a catalyst and the esterified compound to obtain a polyester; and (c) the polyester is granulated to obtain polyester granules; when the amine-containing monomer is the water-soluble chitosan, the weight ratio of the amine-containing monomer to the polyester granules is in the range of 0.01 or more and less than 0.15; when the amine-containing monomer is the N-(hydroxyethyl)piperazine, the weight ratio of the amine-containing monomer to the polyester granules is in the range of 0.05 or more and less than 0.

75.

2. The method for manufacturing polyester pellets as described in claim 1, wherein, When the amine-containing monomer is the water-soluble chitosan, the weight ratio of the amine-containing monomer to the polyester particle ranges from 0.01 to 0.

1.

3. The method for manufacturing polyester pellets as described in claim 1, wherein, When the amine-containing monomer is N-(hydroxyethyl)piperazine, the weight ratio of the amine-containing monomer to the polyester particle ranges from 0.05 to 0.

5.

4. The method for manufacturing polyester pellets as described in claim 1, wherein, Based on 100 parts by weight of terephthalic acid, the amount of ethylene glycol ranges from 27.6 parts by weight to 46.5 parts by weight.

5. The method for manufacturing polyester pellets as described in claim 1, wherein, The esterification solution also contains a crystallization inhibitor selected from at least one of 1,2-propanediol and 2-methyl-1,3-propanediol.

6. The method for manufacturing polyester pellets as described in claim 5, wherein, When the crystallization inhibitor is 1,2-propanediol, the amount of crystallization inhibitor used is greater than 0 parts by weight and less than 3.1 parts by weight, based on 100 parts by weight of terephthalic acid.

7. The method for manufacturing polyester pellets as described in claim 5, wherein, When the crystallization inhibitor is 2-methyl-1,3-propanediol, the amount of the crystallization inhibitor is greater than 0 parts by weight and less than 23.5 parts by weight, based on 100 parts by weight of terephthalic acid.

8. The method for manufacturing polyester pellets as described in claim 5, wherein, When the crystallization inhibitor is 1,2-propanediol or 2-methyl-1,3-propanediol, the amount of crystallization inhibitor used is greater than 0 parts by weight and less than 26.6 parts by weight, based on 100 parts by weight of terephthalic acid.

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