A method for manufacturing a melt-blown polyester and a filter thereof

Abstract

The application discloses a kind of polyester for melt blowing and its filtering manufacturing method, belong to high polymer material field.The raw material of this high polymer polyester contains aliphatic dibasic acid glycol ester, the intrinsic viscosity of polyester is between 0.45~0.6dL·g ‑1 Between, the melting point of polyester is 190~230 DEG C.A kind of modified PET melt blowing polyester material is obtained by the application, and the melt blowing nonwoven fabric prepared from the material has high mechanical strength and filtering performance, reduces the complex process required for preparing PET / PP filtering material by traditional spunbonded fabric / melt blown fabric / spunbonded fabric (SMS) method, reduces technical difficulty and production cost, and the single substance of filtering material is beneficial to the recycling and recycling of filtering product.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a meltblown polyester and a method for manufacturing the same. Background Technology

[0002] Meltblown nonwoven fabric is produced using polymer meltblown direct web forming technology. The resulting fibers have fine diameters, small pores, high porosity, and good uniformity, offering advantages such as high filtration efficiency and strong barrier properties. It has wide applications in gas and liquid filtration. To meet the processing requirements of meltblown technology, meltblown materials need to possess very high melt flow rates (melt index) and narrow molecular weight distributions. Polypropylene (PP), due to its long-chain molecular structure, has a high melt index and a low melting point, perfectly matching the processing performance requirements of meltblown production lines, and accounts for over 90% of all meltblown raw materials. However, meltblown fibers made from PP have low strength and insufficient inter-fiber bonding strength, resulting in poor mechanical properties, low elongation, and poor wear resistance. Filter materials made solely from PP often have a short service life. To improve this, polyethylene terephthalate (PET) has become a focus of attention. PET materials possess high mechanical strength, good barrier properties, and chemical resistance, leading to their widespread industrial application in the fiber industry. However, compared to PP materials, PET has a higher melting point and lower melt flow index, making pure PET polyester difficult to use as a raw material for meltblown production on existing meltblown equipment. Currently, filter materials prepared from PET and PP are often composite nonwoven fabrics made by thermally bonding spunbond PET nonwoven fabrics with meltblown PP nonwoven fabrics. PET acts as a support layer, providing mechanical strength, while meltblown PP acts as an intermediate layer, providing filtration performance. This method results in complex manufacturing processes, intricate procedures, high production difficulty, and high production costs. Furthermore, the non-single-material composition makes recycling and reuse of the product challenging. Summary of the Invention

[0003] To address the shortcomings of the prior art, the present invention aims to provide a method for preparing meltblown polyester and its filter material, using modified PET polyester as raw material to achieve the preparation of filter material.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A meltblown polyester, wherein the raw material of the polyester contains polyethylene glycol ester of aliphatic dicarboxylic acid, and the intrinsic viscosity of the polyester is 0.45–0.6 dL·g. -1 Between these ranges, the melting point of polyester is 190–230℃.

[0006] In the technical solution of this invention, the melt index of the polyester used for meltblown is between 130 and 200 g / 10 min.

[0007] In the technical solution of this invention: the melt crystallization and semi-crystallization cycle t of the meltblown polyester 1 / 2 Between 2.5 and 4.0 seconds.

[0008] In the technical solution of this invention, the polyester is made from terephthalic acid, isophthalic acid, ethylene glycol ester of aliphatic dicarboxylic acid and ethylene glycol.

[0009] In the technical solution of this invention: the total mass of terephthalic acid, isophthalic acid, and polyethylene glycol aliphatic dicarboxylic acid in the raw materials is 100%, then terephthalic acid accounts for 80%-90%, isophthalic acid accounts for 5%-10%, and polyethylene glycol aliphatic dicarboxylic acid accounts for 5%-10%.

[0010] In the technical solution of this invention: the molar ratio of diol and diacid in the raw materials is 1 to 1.5:1, wherein the diol is ethylene glycol, and the diacid is terephthalic acid and isophthalic acid.

[0011] In the technical solution of this invention: the polyaliphatic dicarboxylic acid glycol ester can be one or more of polyethylene malonic acid (PEP), polyethylene succinate (PEB), polyethylene glutarate (PEG), polyethylene adipate (PEA), and polyethylene octanoate (PES).

[0012] A method for preparing the above-mentioned meltblown polyester, wherein the preparation method is a direct esterification-melt polycondensation method.

[0013] In the above preparation method: the catalyst used in the direct esterification-melt polycondensation method is antimony glycolate, and the antimony atoms account for 100-300 ppm of the total polyester mass; the temperature of the esterification reaction is 250-260℃, the temperature of the polycondensation reaction is 280-285℃, the time of the polycondensation reaction is 70-90 min, and the pressure of the polycondensation reaction is below 100 Pa absolute pressure.

[0014] A nonwoven filter material is disclosed, which is prepared by drying the aforementioned meltblown polyester chips and then passing them through a meltblown apparatus. The meltblown nonwoven fabric prepared from the aforementioned meltblown polyester has a tensile strength in the MD direction of 23–30 N and an MD elongation of 29–52%. The meltblown nonwoven fabric prepared from the aforementioned meltblown polyester has a tensile strength in the TD direction of 20–28 N and a TD elongation of 20–44%.

[0015] The filtration efficiency of the meltblown nonwoven fabric prepared from the above-mentioned meltblown polyester is between 90.1% and 99%, and the filtration resistance is between 17.9 and 34.9 Pa.

[0016] In the technical solution of this invention: the intrinsic viscosity is greater than 0.6 dL·g -1 Polyester has poor flowability, and the extrusion swell effect results in coarser filaments and poor filtration performance; its intrinsic viscosity is less than 0.45 dL·g. -1 The melting and crystallization semi-crystallization period of the filament bundles is relatively short, the crystallization is faster, the adhesion between the filament bundles is poor, and the resulting meltblown fabric has poor strength.

[0017] The basis weight of the meltblown nonwoven fabric prepared from the above-mentioned meltblown polyester is 58-62 g / m². 2 The material has a basis weight of 60 g / m³. 2 At that time, the MD tensile force was 21-30N, the MD elongation was 29-52%, the TD tensile force was 20-28N, and the TD elongation was 20-44%. The meltblown wire diameter was 4.8-6.9μm, the filtration efficiency was 92.3-99%, and the filtration resistance was 17.9-34.9Pa.

[0018] The beneficial effects of this invention are:

[0019] This invention provides a modified PET meltblown polyester material. Meltblown nonwoven fabrics prepared from this material possess both high mechanical strength and filtration performance. This reduces the complex processes required for preparing PET / PP filter materials using the traditional spunbond / meltblown / spunbond (SMS) method, lowering the technical difficulty and production cost. Furthermore, the diversification of the filter material facilitates the recycling and reuse of the filter products. Detailed Implementation

[0020] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto:

[0021] Example 1

[0022] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene adipate (PEA) for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 190°C, a melt index of 188 g / 10 min, and a half-crystallization period (t1 / 2) of 3.2 s.

[0023] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 4.9 μm, a maximum tensile strength (MD) of 25 N, an MD elongation of 42%, a maximum tensile strength (TD) of 27 N, and a TD elongation of 35%. The filtration efficiency was 99.0%, and the filtration resistance was 34.9 Pa.

[0024] Example 2

[0025] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 86%, isophthalic acid for 7%, and polyethylene adipate for 7%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 211°C, a melt index of 165 g / 10 min, and a half-crystallization period (t1 / 2) of 3.0 s.

[0026] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 61 g / m², a fiber diameter of 5.0 μm, a maximum tensile strength (MD) of 27 N, an MD elongation of 41%, a maximum tensile strength (TD) of 25 N, and a TD elongation of 37%. The filtration efficiency was 98.7%, and the filtration resistance was 32.2 Pa.

[0027] Example 3

[0028] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with 90% terephthalic acid, 5% isophthalic acid, and 5% polyethylene adipate. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 230°C, a melt index of 130 g / 10 min, and a half-crystallization period (t1 / 2) of 2.5 s.

[0029] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 59 g / m², a fiber diameter of 5.2 μm, a maximum tensile strength (MD) of 29 N, an MD elongation of 40%, a maximum tensile strength (TD) of 21 N, and a TD elongation of 32%. The filtration efficiency was 97.8%, and the filtration resistance was 33.4 Pa.

[0030] Example 4

[0031] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene adipate for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 60 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.45 dL / g, a Tm of 190°C, a melt index of 200 g / 10 min, and a half-crystallization period (t1 / 2) of 2.8 s.

[0032] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 4.8 μm, a maximum tensile strength (MD) of 23 N, an MD elongation of 52%, a maximum tensile strength (TD) of 20 N, and a TD elongation of 20%. The filtration efficiency was 92.3%, and the filtration resistance was 22.4 Pa.

[0033] Example 5

[0034] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene adipate for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 80 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.55 dL / g, a Tm of 190°C, a melt index of 160 g / 10 min, and a half-crystallization period (t1 / 2) of 3.5 s.

[0035] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 6.5 μm, a maximum tensile strength (MD) of 30 N, an MD elongation of 33%, a maximum tensile strength (TD) of 23 N, and a TD elongation of 44%. The filtration efficiency was 99.2%, and the filtration resistance was 34.5 Pa.

[0036] Example 6

[0037] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene adipate for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 90 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.60 dL / g, a Tm of 190°C, a melt index of 148 g / 10 min, and a half-crystallization period (t1 / 2) of 4.0 s.

[0038] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 6.9 μm, a maximum tensile strength (MD) of 21 N, an MD elongation of 29%, a maximum tensile strength (TD) of 27 N, and a TD elongation of 25%. The filtration efficiency was 90.1%, and the filtration resistance was 17.9 Pa.

[0039] Example 7

[0040] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene succinate (PEB) for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 195°C, a melt index of 153 g / 10 min, and a half-crystallization period (t1 / 2) of 3.2 s.

[0041] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 5.3 μm, a maximum tensile strength (MD) of 29 N, an MD elongation of 37%, a maximum tensile strength (TD) of 26 N, and a TD elongation of 30%. The filtration efficiency was 98.6%, and the filtration resistance was 33.5 Pa.

[0042] Example 8

[0043] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene glutarate (PEG) for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 193°C, a melt index of 155 g / 10 min, and a half-crystallization period (t1 / 2) of 3.4 s.

[0044] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 5.1 μm, a maximum tensile strength (MD) of 30 N, an MD elongation of 38%, a maximum tensile strength (TD) of 28 N, and a TD elongation of 33%. The filtration efficiency was 98.8%, and the filtration resistance was 34.1 Pa.

[0045] Reference example 1

[0046] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and polyethylene glycol esters of aliphatic dicarboxylic acids, with terephthalic acid accounting for 76%, isophthalic acid for 12%, and polyethylene adipate for 12%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 186°C, a melt index of 162 g / 10 min, and no obvious melt crystallization peak.

[0047] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 61 g / m², a fiber diameter of 8.2 μm, a maximum tensile strength (MD) of 61 N, an MD elongation of 93%, a maximum tensile strength (TD) of 15 N, and a TD elongation of 3%. The filtration efficiency was 69.3%, and the filtration resistance was 11.5 Pa.

[0048] Reference example 2

[0049] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 96%, isophthalic acid for 2%, and polyethylene adipate for 2%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 240°C, a melt index of 123 g / 10 min, and a half-crystallization period (t1 / 2) of 2.0 s.

[0050] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 5.5 μm, a maximum tensile strength (MD) of 25 N, an MD elongation of 5%, a maximum tensile strength (TD) of 14 N, and a TD elongation of 3%. The filtration efficiency was 97.5%, and the filtration resistance was 25.6 Pa.

[0051] Reference example 3

[0052] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene adipate for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 50 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.40 dL / g, a Tm of 190°C, a melt index of 230 g / 10 min, and a half-crystallization period (t1 / 2) of 2.1 s.

[0053] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 5.4 μm, a maximum tensile strength (MD) of 12 N, an MD elongation of 33%, a maximum tensile strength (TD) of 21 N, and a TD elongation of 42%. The filtration efficiency was 95.5%, and the filtration resistance was 30.2 Pa.

[0054] Reference example 4

[0055] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 10%, and polyethylene adipate for 10%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 60 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.45 dL / g, a Tm of 190°C, a melt index of 200 g / 10 min, and a half-crystallization period (t1 / 2) of 2.1 s.

[0056] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 61 g / m², a fiber diameter of 8.5 μm, a maximum tensile strength (MD) of 10 N, an MD elongation of 12%, a maximum tensile strength (TD) of 13 N, and a TD elongation of 2%. The filtration efficiency was 67.2%, and the filtration resistance was 14.3 Pa.

[0057] Reference example 5

[0058] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with terephthalic acid accounting for 80%, isophthalic acid for 15%, and polyethylene adipate for 5%. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 188°C, a melt index of 162 g / 10 min, and a half-crystallization period (t1 / 2) of 4.8 s.

[0059] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 6.9 μm, a maximum tensile strength (MD) of 15 N, an MD elongation of 37%, a maximum tensile strength (TD) of 16 N, and a TD elongation of 33%. The filtration efficiency was 84.5%, and the filtration resistance was 22.4 Pa.

[0060] Reference example 6

[0061] The raw materials for meltblown polyester consist of 100% terephthalic acid, isophthalic acid, and ethylene glycol aliphatic dicarboxylic acid, with 75% terephthalic acid, 20% isophthalic acid, and 5% polyethylene adipate. The molar ratio of ethylene glycol to the total terephthalic acid and isophthalic acid is 1.2. The catalyst is antimony glycolate, with antimony atoms comprising 200 ppm of the total polyester mass. A conventional esterification reaction is carried out at 256°C via direct esterification-melt polycondensation. After esterification, a polycondensation reaction is performed at 283°C and below 100 Pa for 70 min. After the reaction, the meltblown polyester is obtained by extrusion, stretching, pelletizing, and drying. The polyester has an intrinsic viscosity of 0.50 dL / g, a Tm of 176°C, a melt index of 180 g / 10 min, and no obvious melt crystallization peak.

[0062] Meltblown polyester chips were dried and then processed into nonwoven filter material using a meltblown extrusion apparatus. The spinneret had 2600 holes with a diameter of 0.32 mm. The meltblown nonwoven filter material was prepared under the following conditions: screw extrusion temperature 290℃, die temperature 290℃, hot air temperature 295℃, hot air volume 27%, and DCD 100 mm. The prepared meltblown nonwoven filter material had a basis weight of 60 g / m², a fiber diameter of 7.9 μm, a maximum tensile strength (MD) of 11 N, an MD elongation of 40%, a maximum tensile strength (TD) of 11 N, and a TD elongation of 42%. The filtration efficiency was 65.3%, and the filtration resistance was 11 Pa.

[0063] Test method:

[0064] Intrinsic viscosity: conforms to national standard GB / T 14190-2017 "Test method for fiber grade polyester chips".

[0065] Melting point: The melting point of the polyester was determined by DSC (differential scanning calorimetry) under nitrogen protection. The temperature was increased from 25°C to 290°C at a rate of 10°C / min, held at the temperature for 5 min, and then decreased from 290°C to 25°C at a rate of 10°C / min.

[0066] Melt semi-crystallization period t1 / 2: The DSC method was used for testing. Under nitrogen protection, the temperature was increased from 25℃ to 290℃ at a heating rate of 10℃ / min, held at the temperature for 5 min, and then decreased from 290℃ to 25℃ at a cooling rate of 10℃ / min to obtain the DSC curve of the polyester. The melt semi-crystallization period t1 / 2 was calculated for the melt crystallization part of the curve using the Jeziomy model.

[0067] Melt flow index: Determination of melt mass flow rate (MFR) and melt volumetric flow rate (MVR) for thermoplastic plastics was performed according to national standard GB / T 3682.1-2018. The selected test temperature was 260℃ and the load was 2.16 kg.

[0068] Table 1

[0069]

[0070]

[0071] Table 2

[0072]

[0073] The experimental results of the embodiments and reference examples of this invention are listed in Table 1. This invention prepares PET materials for meltblown fabric by composite modification of aliphatic monomers and polar aromatic monomers, and realizes the preparation of PET meltblown filter media through meltblown equipment. This invention limits the intrinsic viscosity, melting point, melt index, and semi-crystallization period of the PET meltblown material, and evaluates the fiber diameter, mechanical properties, and filtration performance of the prepared meltblown fabric material.

[0074] The mechanism by which polyester materials affect the properties of meltblown nonwoven fabric is as follows:

[0075] The intrinsic viscosity and melting point of polyester collectively affect its melt flow index. When the melt flow index of polyester is too low, it can lead to excessive pressure in the meltblown assembly, resulting in poor spinning and difficulty in fabric formation. At the same time, the content of modified components, melting point, melt flow index, and melt semi-crystallization period of polyester collectively affect the performance of the filter media. Therefore, the performance of the final filter media cannot be measured or predicted by a single indicator. Modifying polyester components can reduce the pressure of meltblown components and simplify meltblowing by lowering the melt flow index and melting point of polyester. Simultaneously, lowering the polyester melting point and extending the melt-crystallization period can improve the thermal adhesion between meltblown filaments and enhance the mechanical properties of the filter media. However, modifying components can increase the diameter of the polyester filaments, leading to a decrease in filtration efficiency. Furthermore, excessively high levels of modifying components can cause the melt-crystallization period to be too short or disappear, further reducing the mechanical properties of the filter media. The intrinsic viscosity of polyester directly affects its melt flow index; higher intrinsic viscosity results in a lower melt flow index. The polyester melting point primarily influences the melt flow index and the thermal adhesion between meltblown filaments; lowering the melting point effectively improves the mechanical properties of the filter media. The polyester melt flow index reflects the flow properties of the polyester melt and directly affects the meltblown process and the fabric formation performance of the meltblown cloth. Increasing the melt flow index is beneficial for improving the mechanical properties and filtration efficiency of the filter media. The melt-crystallization period reflects the crystallization performance of polyester; a longer period indicates slower crystallization, which is beneficial for meltblown fabric formation. However, excessively slow crystallization can also lead to a decrease in the mechanical properties of the filter media. The diameter of the meltblown wire directly affects the size of the pores on the surface of the filter media. The smaller the diameter of the meltblown wire, the better the filtration effect, but the greater the filtration resistance.

[0076] In this invention, compared with Reference Examples 1, 5, and 6, when the polyester modification content exceeds the scope of this invention, although the melt flow index is higher, the diameter of the meltblown fiber bundles is larger, resulting in poor filtration effect of the final filter material; moreover, the polyester melt crystallization semi-crystallization cycle is too long, crystallization is slow, the tensile strength in the MD and TD directions is small, and the mechanical strength is poor. Compared with Reference Example 2, when the polyester modification content is lower than the scope of this invention, the polyester melting point is higher, the melt flow index is lower, the adhesion between the meltblown fiber bundles is poor, the elongation in the MD and TD directions of the final filter material is shorter, and the tensile properties are poor. Compared with Reference Example 3, when the intrinsic viscosity of the polyester is lower than the scope of this invention, although the melt flow index is higher, the polyester melt crystallization semi-crystallization cycle is short, crystallization is fast, the adhesion between the meltblown fiber bundles is poor, the final filter material fabrication effect is poor, the tensile strength in the MD and TD directions is small, and the mechanical strength is poor. Compared with Reference Example 4, when the intrinsic viscosity of polyester is higher than the range of the present invention, the melt index of polyester is low, the diameter of meltblown filament bundles becomes thicker, the filtration effect becomes worse, and the adhesion between filament bundles becomes worse. In the end, the filtration effect and mechanical properties of the filter material are significantly reduced.

Claims

1. A meltblown polyester, characterized in that: This polyester contains aliphatic dicarboxylic acid glycol esters, and its intrinsic viscosity is between 0.45 and 0.6 dL·g. -1 Between these temperatures, the melting point of polyester is 190~230℃; Polyester is made from terephthalic acid, isophthalic acid, ethylene glycol ester of aliphatic dicarboxylic acid and ethylene glycol; If the total mass of terephthalic acid, isophthalic acid, and ethylene glycol esters of aliphatic dicarboxylic acids in the raw materials is 100%, then terephthalic acid accounts for 80%-90%, isophthalic acid accounts for 5%-10%, and ethylene glycol esters of aliphatic dicarboxylic acids account for 5%-10%. The molar ratio of diol to diacid in the raw material is 1~1.5:1, wherein the diol is ethylene glycol, and the diacid is terephthalic acid and isophthalic acid; The aliphatic dicarboxylic acid glycol ester is one or more of polyethylene malonic acid, polyethylene succinate, polyethylene glutarate, polyethylene adipate, and polyethylene octanoate. The melt crystallization and semi-crystallization cycle t of meltblown polyester 1 / 2 Between 2.5 and 4.0 seconds.

2. The polyester for meltblown fabrication according to claim 1, characterized in that: The melt flow index of meltblown polyester is between 130 and 200 g / 10 min.

3. A method for preparing meltblown polyester according to claim 1, characterized in that: The preparation method is direct esterification-melt polycondensation.

4. The preparation method according to claim 3, characterized in that: The catalyst used in the direct esterification-melt polycondensation method is antimony glycolate, with antimony atoms accounting for 100~300 ppm of the total polyester mass; the esterification reaction temperature is 250~260℃, the polycondensation reaction temperature is 280~285℃, the polycondensation reaction time is 70~90 min, and the polycondensation reaction pressure is below 100 Pa absolute pressure.

5. A nonwoven filter material, characterized in that: The nonwoven filter material is prepared by drying the meltblown polyester chips of claim 1 and then passing them through a meltblown device; the material has a basis weight of 60 g / m³. 2 At that time, the MD tensile force was 21-30N, the MD elongation was 29-52%, the TD tensile force was 20-28N, and the TD elongation was 20-44%; the meltblown wire diameter was 4.8-6.9μm, the filtration efficiency was 92.3-99%, and the filtration resistance was 17.9-34.9 Pa.

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