Preparation method of modified PET film material

Abstract

The present invention relates to the technical field of polyethylene terephthalate, and discloses a preparation method of a modified PET film material, 100 parts by weight of hyperbranched polyester quaternary ammonium salt, 0.5-3 parts by weight of polyethylene terephthalate, etc. are extruded, granulated, and then blown film is formed to obtain a modified PET film material. The hyperbranched polyester quaternary ammonium salt of the present invention contains a polyester structural unit, has good compatibility with PET polyester, and has a hyperbranched three-dimensional dendritic network structure, can play a good toughening effect, and is conducive to improving the tensile strength and elongation at break of PET film materials. And containing better quaternary ammonium salt antibacterial sites, while uniformly dispersed in the PET polyester film matrix, it is conducive to improving the antibacterial properties of film materials.

Description

Technical Field

[0001] This invention relates to the field of polyethylene terephthalate (PET) technology, specifically to a method for preparing modified PET film materials. Background Technology

[0002] PET (polyethylene terephthalate) has good film-forming properties and can be processed into high-performance film materials through blow molding, multilayer co-extrusion, and casting, which are widely used in printing, vacuum metallized products, traffic reflective signs, food and pharmaceutical packaging, and other fields. Modifying PET film materials to impart better antibacterial, heat-resistant, and mechanical properties is a research hotspot. Hyperbranched polymers are three-dimensional macromolecular polymers with many branching points and non-entangled molecular chains. They can be used as processing aids, crystallization aids, and toughening agents for polymer materials, and have a wide range of applications. Patent CN115073735B discloses a hyperbranched semi-aromatic polyester imide polymer and its preparation method. Using aromatic polycarboxylic acids / polyanhydrides, monoamino polyols, and monoamino monools as raw materials, the hyperbranched polyester imide obtained through a melt polyester and imidization reaction can improve the crystallization temperature and crystallinity of PET. However, the products prepared by this patent have poor mechanical properties, antibacterial properties, and heat resistance. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for preparing modified PET film materials with heat resistance and antibacterial properties.

[0004] The preparation method of modified PET film material includes the following steps:

[0005] S1. Add ethanol to the reaction vessel, with intermediate 1 and intermediate 2 in a molar ratio of (1.4-1.6):1. Heat to 75-85℃ and react for 24-36 hours. Filter, wash the precipitate with ethanol, and dry to obtain hyperbranched polyester quaternary ammonium salt. The reaction formula is as follows:

[0006] ;

[0007] S2. Mix 100 parts by weight of polyethylene terephthalate, 0.5-3 parts by weight of hyperbranched polyester quaternary ammonium salt, and 0.3-0.5 parts by weight of antioxidant, add to a twin-screw extruder, extrude, granulate, and then blown into a film using an extrusion blown film machine to obtain modified PET film material.

[0008] Further, the preparation method of intermediate 1 is as follows: Tetrahydrofuran and water in a volume ratio of 1:(0.3-0.4) are added to a reaction vessel, along with 1,3-dichloro-2-propanol and sodium hydroxide. After stirring, 2-chloro-4,6-diphenyl-1,3,5-triazine is added. The mixture is heated to 65-70°C and refluxed for 4-7 hours. After cooling, hydrochloric acid solution is added dropwise for neutralization. Tetrahydrofuran is removed by vacuum distillation. The precipitate is volatilized by heating and then cooled in an ice-water bath and recrystallized to obtain intermediate 1. The reaction formula is as follows:

[0009] .

[0010] Furthermore, the molar ratio of 1,3-dichloro-2-propanol, sodium hydroxide, and 2-chloro-4,6-diphenyl-1,3,5-triazine is 1:(1-1.2):(1-1.1).

[0011] Further, the preparation method of intermediate 2 is as follows: Toluene, trimethylolpropane, N,N-dimethylglycine, and p-toluenesulfonic acid are added to a reaction vessel in a molar ratio of 1:(3-3.9):(0.24-0.33). The mixture is heated to 90-100℃ and reacted for 12-18 hours. The mixture is then concentrated under reduced pressure to remove low-boiling-point substances, washed with petroleum ether, and dried to obtain intermediate 2. The reaction formula is as follows:

[0012] .

[0013] Furthermore, the temperature of each section of the extruder in S2 is 215-265℃; the temperature of each section of the extrusion blown film machine is 275-290℃, the blow-up ratio is 2.5-3.5, and the traction speed is 4-7m / min.

[0014] Beneficial Effects: This invention utilizes intermediate 1 containing a diphenyltriazine structure and intermediate 2 containing multiple ester groups to undergo a quaternization polymerization reaction to obtain a hyperbranched polyester quaternary ammonium salt. This salt is then melt-mixed with polyethylene terephthalate (PET) and blow-molded to obtain a modified PET film material. This hyperbranched polyester quaternary ammonium salt contains polyester structural units, exhibits excellent compatibility with PET polyester, and possesses a hyperbranched three-dimensional dendritic network structure. It forms chain entanglement with the PET molecular chains, creating physical crosslinking sites and providing excellent toughening effects. This improves the mechanical properties of the PET film material, resulting in higher tensile strength and elongation at break.

[0015] The hyperbranched polyester quaternary ammonium salt of the present invention contains a heat-resistant diphenyltriazine structure, which has good resistance to thermal decomposition. When added to PET, it helps to improve the initial thermal decomposition temperature and heat resistance of PET film material.

[0016] The hyperbranched polyester quaternary ammonium salt of the present invention contains a three-dimensional dendritic network structure, which provides more antibacterial sites. Furthermore, it contains a polyester structure, which improves its compatibility with PET polyester and allows it to be uniformly dispersed in the PET polyester film matrix, thereby enhancing the antibacterial performance of the film material. Detailed Implementation

[0017] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0018] Example 1: A method for preparing modified PET film material, comprising the following steps:

[0019] (1) Add 20 mL of tetrahydrofuran, 6 mL of water, 6 mmol of 1,3-dichloro-2-propanol, and 6 mmol of sodium hydroxide to the reaction vessel. After stirring, add 6 mmol of 2-chloro-4,6-diphenyl-1,3,5-triazine. Heat to 70 °C and reflux for 4 h. After cooling, add hydrochloric acid solution dropwise to neutralize. Remove tetrahydrofuran by vacuum distillation. Heat to volatilize and precipitate the precipitate. Then cool in an ice-water bath and recrystallize to obtain intermediate 1.

[0020] (2) Add 15 ml toluene, 4 mmol trimethylolpropane, 12 mmol N,N-dimethylglycine and 1.32 mmol p-toluenesulfonic acid to the reaction vessel, heat to 90 °C, react for 12 h, concentrate under reduced pressure to remove low-boiling substances, wash with petroleum ether, dry, and obtain intermediate 2.

[0021] (3) Add 50 mL of ethanol, 15 mmol of intermediate 1 and 10 mmol of intermediate 2 to the reaction vessel, heat to 75 °C, react for 36 h, filter, wash the precipitate with ethanol, dry, and obtain hyperbranched polyester quaternary ammonium salt.

[0022] (4) Mix 100g polyethylene terephthalate, 0.5g hyperbranched polyester quaternary ammonium salt, and 0.3g antioxidant 168, add them to a twin-screw extruder, extrude, and granulate. The temperature of each section of the twin-screw extruder is 215℃, 230℃, 250℃, 265℃, and 260℃. Then, blow the granules into film using an extrusion blown film machine. The temperature of each section is 275℃, 280℃, 290℃, 290℃, and 285℃. The blow-up ratio is 3, and the traction speed is 4m / min to obtain modified PET film material.

[0023] Example 2: A method for preparing modified PET film material, comprising the following steps:

[0024] (1) Add 20 mL of tetrahydrofuran, 8 mL of water, 6 mmol of 1,3-dichloro-2-propanol, and 7.2 mmol of sodium hydroxide to the reaction vessel. After stirring, add 6.6 mmol of 2-chloro-4,6-diphenyl-1,3,5-triazine. Heat to 65 °C and reflux for 7 h. After cooling, add hydrochloric acid solution to neutralize. Remove tetrahydrofuran by vacuum distillation. Heat to volatilize and precipitate the precipitate. Then cool in an ice-water bath and recrystallize to obtain intermediate 1.

[0025] (2) Add 15 ml toluene, 4 mmol trimethylolpropane, 15.6 mmol N,N-dimethylglycine and 0.96 mmol p-toluenesulfonic acid to the reaction vessel, heat to 100 °C, react for 18 h, concentrate under reduced pressure to remove low-boiling substances, wash with petroleum ether, dry, and obtain intermediate 2.

[0026] (3) Add 60 mL of ethanol, 14 mmol of intermediate 1 and 10 mmol of intermediate 2 to the reaction vessel, heat to 85 °C, react for 24 h, filter, wash the precipitate with ethanol, dry, and obtain hyperbranched polyester quaternary ammonium salt.

[0027] (4) Mix 100g polyethylene terephthalate, 1g hyperbranched polyester quaternary ammonium salt, and 0.5g antioxidant 168, add them to a twin-screw extruder, extrude, and granulate. The temperature of each section of the twin-screw extruder is 215℃, 230℃, 250℃, 265℃, and 260℃. Then, blow the granules into film using an extrusion blown film machine. The temperature of each section is 275℃, 280℃, 290℃, 290℃, and 285℃. The blow-up ratio is 3.5, and the traction speed is 7m / min to obtain modified PET film material.

[0028] Example 3: A method for preparing modified PET film material, comprising the following steps:

[0029] (1) Add 80 mL of ethanol, 16 mmol of intermediate 1 (prepared in Example 1) and 10 mmol of intermediate 2 (prepared in Example 1) to the reaction vessel, heat to 80 °C, react for 24 h, filter, wash the precipitate with ethanol, dry, and obtain hyperbranched polyester quaternary ammonium salt.

[0030] (2) Mix 100g polyethylene terephthalate, 2g hyperbranched polyester quaternary ammonium salt, and 0.3g antioxidant 168, add them to a twin-screw extruder, extrude, and granulate. The temperature of each section of the twin-screw extruder is 215℃, 230℃, 250℃, 265℃, and 260℃. Then, blow the granules into film using an extrusion blown film machine. The temperature of each section is 275℃, 280℃, 290℃, 290℃, and 285℃. The blow-up ratio is 2.5, and the traction speed is 5m / min to obtain modified PET film material.

[0031] Example 4: A method for preparing modified PET film material, comprising the following steps:

[0032] (1) Add 60 mL of ethanol, 15 mmol of intermediate 1 (prepared in Example 1) and 10 mmol of intermediate 2 (prepared in Example 1) to the reaction vessel, heat to 85 °C, react for 24 h, filter, wash the precipitate with ethanol, dry, and obtain hyperbranched polyester quaternary ammonium salt.

[0033] (2) Mix 100g polyethylene terephthalate, 3g hyperbranched polyester quaternary ammonium salt, and 0.3g antioxidant 168, add them to a twin-screw extruder, extrude, and granulate. The temperature of each section of the twin-screw extruder is 215℃, 230℃, 250℃, 265℃, and 260℃. Then, blow the granules into film using an extrusion blown film machine. The temperature of each section is 275℃, 280℃, 290℃, 290℃, and 285℃. The blow-up ratio is 3, and the traction speed is 4m / min to obtain modified PET film material.

[0034] Comparative Example 1: A method for preparing PET film material, comprising the following steps:

[0035] (1) Mix 100g of polyethylene terephthalate and 0.3g of antioxidant 168, add them to a twin-screw extruder, extrude, and granulate. The temperature of each section of the twin-screw extruder is 215℃, 230℃, 250℃, 265℃, and 260℃. Then, blow the granules into film using an extrusion blown film machine. The temperature of each section is 275℃, 280℃, 290℃, 290℃, and 285℃. The blow-up ratio is 3, and the traction speed is 4m / min to obtain PET film material.

[0036] Comparative Example 2: A method for preparing modified PET film material, comprising the following steps:

[0037] (1) Add 50 mL of ethanol, 10 mmol of intermediate 1 and 10 mmol of N,N,N',N'-tetramethylethylenediamine to the reaction vessel, heat to 75 °C, react for 36 h, filter, wash the precipitate with ethanol, dry, and obtain polyquaternary ammonium salt.

[0038] (2) Mix 100g of polyethylene terephthalate, 0.5g of polyquaternium salt and 0.3g of antioxidant 168, add them to a twin-screw extruder, extrude and granulate. The temperature of each section of the twin-screw extruder is 215℃, 230℃, 250℃, 265℃ and 260℃. Then the granules are blown into film by an extrusion blown film machine. The temperature of each section is 275℃, 280℃, 290℃, 290℃ and 285℃. The blow-up ratio is 3 and the traction speed is 4m / min to obtain modified PET film material.

[0039] Comparative Example 3: A method for preparing modified PET film material, comprising the following steps:

[0040] (1) Add 50 mL of ethanol, 15 mmol of 1,3-dichloropropane and 10 mmol of intermediate 2 to the reaction vessel, heat to 75 °C, react for 36 h, filter, wash the precipitate with ethanol, dry, and obtain polyester quaternary ammonium salt.

[0041] (2) Mix 100g polyethylene terephthalate, 0.5g hyperbranched polyester quaternary ammonium salt, and 0.3g antioxidant 168, add them to a twin-screw extruder, extrude, and granulate. The temperature of each section of the twin-screw extruder is 215℃, 230℃, 250℃, 265℃, and 260℃. Then, blow the granules into film using an extrusion blown film machine. The temperature of each section is 275℃, 280℃, 290℃, 290℃, and 285℃. The blow-up ratio is 3, and the traction speed is 4m / min to obtain modified PET film material.

[0042] The tensile properties of PET film materials were tested according to the method in GB / T 1040.3-2006.

[0043] Escherichia coli and Staphylococcus aureus were used as test strains, cultured, activated, and diluted into bacterial suspensions (concentration 10). 6 (cfu / mL). 0.2 mL of bacterial suspension was dropped onto the surface of a PET film material, and then the surface of the PET film material was covered with a polyethylene film. The mixture was incubated at 37°C for 24 h. The PET film material and polyethylene film were then washed with 20 mL of 0.8% sodium chloride solution. 0.1 mL of the solution was dropped onto nutrient agar medium and incubated at 37°C for 48 h, followed by viable cell counting.

[0044] Calculate the inhibition rate R. R = (AB) / A × 100%.

[0045] A represents the average recovered bacterial count (cfu / tablet) of the blank control group (PET film material prepared in Comparative Example 1). B represents the average recovered bacterial count (cfu / tablet) of the antibacterial sample group.

[0046] Thermogravimetric analysis was performed on PET film materials using a thermogravimetric analyzer under a nitrogen atmosphere, with a heating rate of 10℃ / min and a test temperature range of 25-800℃.

[0047] Table 1: Performance test results of PET film materials prepared in each embodiment and comparative example

[0048]

[0049] Compared to Comparative Example 1, Examples 1-4 incorporated hyperbranched polyester quaternary ammonium salts, which contain polyester structural units and exhibit excellent compatibility with PET polyester. Furthermore, they possess a hyperbranched three-dimensional dendritic network structure, forming chain entanglement with PET molecular chains and creating physical crosslinking sites, thus providing excellent toughening and improving the mechanical properties of the PET film material, resulting in higher tensile strength and elongation at break. Additionally, the hyperbranched polyester quaternary ammonium salts contain heat-resistant diphenyltriazine structures (…). It has good resistance to thermal decomposition. When added to PET, it helps to increase the initial thermal decomposition temperature (the temperature at which 5% thermal weight loss) and heat resistance of PET film material.

[0050] Comparative Example 2: The reaction of N,N,N,N-tetramethylethylenediamine and intermediate 1 yielded a polyquaternary ammonium salt with linear molecular chains. It did not have a hyperbranched three-dimensional dendritic network structure, nor did it contain a polyester structure. It had poor compatibility with PET polyester, poor toughening effect, and low tensile strength and elongation at break of the film material.

[0051] Comparative Example 3 involved reacting 1,3-dichloropropane and intermediate 2 to obtain a hyperbranched polyester quaternary ammonium salt that did not contain a heat-resistant diphenyltriazine structure, resulting in a lower initial thermal decomposition temperature and poorer heat resistance for the PET film material.

[0052] Table 2: Test results of antibacterial properties of PET film materials prepared in each example and comparative example

[0053]

[0054] After testing, compared with the linear polyquaternary ammonium salt prepared in Comparative Example 2, the hyperbranched polyester quaternary ammonium salt prepared in Examples 1-4 and Comparative Example 3 showed better antibacterial properties, and the resulting modified PET film materials exhibited higher antibacterial rates against bacteria such as Escherichia coli. This is mainly because the hyperbranched polyester quaternary ammonium salt contains a three-dimensional dendritic network structure, resulting in more antibacterial sites. Furthermore, its polyester structure enhances its compatibility with PET polyester, allowing it to be uniformly dispersed within the PET polyester film matrix, which is beneficial for improving the antibacterial properties of the film material.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a modified PET film material, characterized in that: The steps include: S1. Add ethanol to the reaction vessel, the structural formula is The intermediate 1 has the structural formula The intermediate 2 is heated to 75-85°C, reacted for 24-36 hours, filtered, washed with ethanol, and dried to obtain a hyperbranched polyester quaternary ammonium salt; S2, 100 parts by weight of polyethylene terephthalate, 0.5-3 parts by weight of hyperbranched polyester quaternary ammonium salt, and 0.3-0.5 parts by weight of antioxidant are mixed, added into a twin-screw extruder, extruded, granulated, and then the pellets are blown into film by an extrusion film blowing machine to obtain a modified PET film material.

2. The method for preparing the modified PET film material according to claim 1, characterized in that: The molar ratio of the intermediate 1 to the intermediate 2 is (1.4-1.6):

1.

3. The method for preparing the modified PET film material according to claim 2, characterized in that: The preparation method of the intermediate 1 is as follows: tetrahydrofuran, water, 1,3-dichloro-2-propanol, and sodium hydroxide are added into a reaction container, 2-chloro-4,6-diphenyl-1,3,5-triazine is added after stirring, the mixture is heated to 65-70° C., condensed and refluxed for reaction for 4-7 hours, hydrochloric acid solution is added dropwise for neutralization after cooling, tetrahydrofuran is removed by vacuum distillation, a precipitate is precipitated by heating, and then the mixture is cooled in an ice-water bath and recrystallized to obtain the intermediate 1.

4. The method for preparing the modified PET film material according to claim 3, characterized in that: The molar ratio of the 1,3-dichloro-2-propanol, sodium hydroxide and 2-chloro-4,6-diphenyl-1,3,5-triazine is 1:(1-1.2):(1-1.1).

5. The method for preparing the modified PET film material according to claim 3, characterized in that: The volume ratio of tetrahydrofuran to water is 1:(0.3-0.4).

6. The method for preparing the modified PET film material according to claim 2, characterized in that: The preparation method of the intermediate 2 is as follows: toluene, trimethylolpropane, N,N-dimethylglycine, and p-toluenesulfonic acid are added to a reaction container, heated to 90-100° C., reacted for 12-18 hours, concentrated under reduced pressure to remove low boiling points, washed with petroleum ether, and dried to obtain the intermediate 2.

7. The method for preparing the modified PET film material according to claim 6, characterized in that: The molar ratio of trimethylolpropane, N,N-dimethylglycine and p-toluenesulfonic acid is 1:(3-3.9):(0.24-0.33).

8. The method for preparing the modified PET film material according to claim 1, characterized in that: The temperature of each section of the extruder in S2 is 215-265° C.; the temperature of each section of the extrusion film blowing machine is 275-290° C., the blow-up ratio is 2.5-3.5, and the traction speed is 4-7 m / min.

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