Polyester for melt blowing and filtering manufacturing method thereof

Abstract

The invention discloses polyester for melt-blowing and a filtering manufacturing method thereof, and belongs to the field of high polymer materials. The raw materials of the polymer polyester contain aliphatic dibasic acid glycol ester, the intrinsic viscosity of the polyester is 0.45-0.6 dL.g <-1 >, and the melting point of the polyester is 190-230 DEG C. The modified PET melt-blowing polyester material is obtained, a melt-blowing non-woven fabric prepared from the material has high mechanical strength and filtering performance at the same time, complex procedures needed by a traditional spunbond cloth / melt-blowing cloth / spunbond cloth (SMS) method for preparing a PET / PP filtering material are reduced, the technical difficulty and the production cost are reduced, and the method is suitable for large-scale popularization and application. And meanwhile, the filtering material is simple-substance, so that the recovery and cyclic utilization of a filtered product are facilitated.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and in particular relates to a polyester for melt-blowing and a method for manufacturing the polyester and filtering the polyester. Background Art

[0002] Meltblown nonwoven fabrics are made by direct web-forming technology of polymer meltblowing. The prepared fibers have fine diameter, small pores, high porosity, good uniformity, high filtering effect, strong barrier ability and other advantages. They are widely used in the field of gas and liquid filtration. In order to meet the processing requirements of the meltblowing process, the meltblown material needs to have a very high melt flow rate (melt index) and a narrow relative molecular mass distribution. Polypropylene (PP) material has a high melt index and a low melting point due to its long straight chain molecular structure, which meets the processing performance requirements of the meltblown production line for raw materials and occupies more than 90% of all meltblown raw materials. However, the meltblown fibers prepared by PP have low strength and insufficient bonding strength between fibers, so they have poor mechanical ability, small elongation, and are not wear-resistant. The service life of filter materials produced solely with PP is often short. In order to improve this shortcoming, polyethylene terephthalate (PET) material has become the object of people's attention. PET materials have high mechanical strength, good barrier properties and chemical corrosion resistance, etc., and have a high degree of industrial application in the fiber field. However, compared with PP materials, PET materials have a high melting point and a low melt index. Pure PET polyester is difficult to produce as a melt-blown raw material on existing melt-blown equipment. At present, the filter materials prepared with PET and PP as raw materials are often made by hot-melt bonding PET non-woven fabrics prepared by spunbond method and PP non-woven fabrics prepared by meltblown method to form composite non-woven fabric materials. PET material serves as a support layer to provide a certain mechanical strength for the product, and melt-blown PP material serves as an intermediate layer to provide filtering performance for the product. The filter material prepared in this way has a complex preparation process, cumbersome procedures, high production technology difficulty, high production cost, and the product material is not a single material, so it is difficult to recycle and reuse the product. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing melt-blown polyester and its filter material, using modified PET polyester as raw material to achieve the preparation of the filter material.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A polyester for melt-blowing, wherein the raw material of the polyester contains aliphatic dibasic acid ethylene glycol ester, and the intrinsic viscosity of the polyester is 0.45 to 0.6 dL·g -1 The melting point of polyester is between 190 and 230°C.

[0006] In the technical solution of the present invention: the melt index of the polyester for meltblowing is between 130 and 200 g / 10 min.

[0007] In the technical solution of the present invention: the melt crystallization half crystallization period t of the meltblown polyester 1 / 2 Between 2.5 and 4.0 seconds.

[0008] In the technical scheme of the present invention, polyester uses terephthalic acid, isophthalic acid, aliphatic dibasic acid ethylene glycol ester and ethylene glycol as raw materials.

[0009] In the technical scheme of the present invention, if the total mass of terephthalic acid, isophthalic acid and aliphatic dibasic acid ethylene glycol ester in the raw materials is 100%, then terephthalic acid accounts for 80%-90%, isophthalic acid accounts for 5%-10%, and polyaliphatic dibasic acid ethylene glycol ester accounts for 5%-10%.

[0010] In the technical scheme of the present invention, the molar ratio of diol to dibasic acid in the raw material is 1-1.5:1, the diol is ethylene glycol, and the dibasic acid is terephthalic acid and isophthalic acid.

[0011] In the technical solution of the present invention: the poly(ethylene glycol) of aliphatic dibasic acid can be one or more of poly(ethylene glycol) malonate (PEP), poly(ethylene glycol) succinate (PEB), poly(ethylene glycol) glutarate (PEG), poly(ethylene glycol) adipate (PEA), poly(ethylene glycol) suberate (PES), etc.

[0012] A method for preparing the above-mentioned polyester for meltblowing is a direct esterification-melt polycondensation method.

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

[0014] A non-woven filter material, the non-woven filter fabric is prepared by drying the above-mentioned melt-blown polyester slices and passing through a melt-blown device. The MD direction tension of the melt-blown non-woven fabric prepared with the above-mentioned melt-blown polyester as a raw material is between 23 and 30N, and the MD elongation is between 29 and 52%. The TD direction tension of the melt-blown non-woven fabric prepared with the above-mentioned melt-blown polyester as a raw material is between 20 and 28N, and the TD elongation is between 20 and 44%.

[0015] The filtration efficiency of the melt-blown nonwoven fabric prepared with the above-mentioned melt-blown polyester as raw material is between 90.1 and 99%, and the filtration resistance is between 17.9 and 34.9 Pa.

[0016] In the technical solution of the present invention: the intrinsic viscosity is greater than 0.6dL·g -1 The polyester has poor fluidity, the extrusion expansion effect leads to coarser tows and poor filtration performance; the intrinsic viscosity is less than 0.45dL·g -1 The semi-crystallization period of the filament bundle melt crystallization is smaller, the crystallization is faster, the bonding between the filament bundles is poor, and the strength of the meltblown cloth produced is poor.

[0017] The melt-blown nonwoven fabric prepared with the above-mentioned melt-blown polyester as raw material has a gram weight of 58 to 62 g / m 2 . ; The material weight is 60g / m 2 When the MD tension is 21-30N, the MD elongation is 29-52%, the TD tension is 20-28N, and the TD elongation is 20-44%. The melt-blown filament diameter is 4.8-6.9μm, the filtration efficiency is 92.3-99%, and the filtration resistance is 17.9-34.9Pa.

[0018] Beneficial effects of the present invention:

[0019] The present invention obtains a polyester material for meltblowing of modified PET. The meltblown nonwoven fabric prepared with the material has both high mechanical strength and filtering performance, reduces the complex steps required for preparing PET / PP filter materials by the traditional spunbond fabric / meltblown fabric / spunbond fabric (SMS) method, reduces the technical difficulty and production cost, and the homogenization of the filter material is conducive to the recovery and recycling of the filter products. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto:

[0021] Example 1

[0022] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene adipate accounts for (PEA) 10%. The molar ratio of ethylene glycol to the total of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 190°C, a melt index of 188g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 3.2s.

[0023] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 4.9 μm, an MD tensile force of 25 N, and an MD elongation of 42%; a TD tensile force of 27 N, and a TD elongation of 35%; a filtration efficiency of 99.0%, and a filtration resistance of 34.9 Pa.

[0024] Example 2

[0025] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 86%, isophthalic acid accounts for 7%, and polyethylene adipate accounts for 7%. The molar ratio of ethylene glycol to the total of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 211°C, a melt index of 165g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 3.0s.

[0026] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 61 g / m2, a fiber diameter of 5.0 μm, an MD tensile force of 27 N, and an MD elongation of 41%; a TD tensile force of 25 N, and a TD elongation of 37%; a filtration efficiency of 98.7%, and a filtration resistance of 32.2 Pa.

[0027] Example 3

[0028] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 90%, isophthalic acid accounts for 5%, and polyethylene adipate accounts for 5%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 230°C, a melt index of 130g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 2.5s.

[0029] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 59 g / m2, a fiber diameter of 5.2 μm, an MD tensile force of 29 N, and an MD elongation of 40%; a TD tensile force of 21 N, and a TD elongation of 32%; a filtration efficiency of 97.8%, and a filtration resistance of 33.4 Pa.

[0030] Example 4

[0031] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene adipate accounts for 10%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 60min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.45dL / g, a Tm of 190°C, a melt index of 200g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 2.8s.

[0032] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 4.8 μm, an MD tensile force of 23 N, and an MD elongation of 52%; a TD tensile force of 20 N, and a TD elongation of 20%; a filtration efficiency of 92.3%, and a filtration resistance of 22.4 Pa.

[0033] Example 5

[0034] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene adipate accounts for 10%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 80min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.55dL / g, a Tm of 190°C, a melt index of 160g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 3.5s.

[0035] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 6.5 μm, an MD tensile force of 30 N, and an MD elongation of 33%; a TD tensile force of 23 N, and a TD elongation of 44%; a filtration efficiency of 99.2%, and a filtration resistance of 34.5 Pa.

[0036] Example 6

[0037] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene adipate accounts for 10%. The molar ratio of ethylene glycol to the total of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 90min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.60dL / g, a Tm of 190°C, a melt index of 148g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 4.0s.

[0038] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 6.9 μm, an MD tensile force of 21 N, and an MD elongation of 29%; a TD tensile force of 27 N, and a TD elongation of 25%; a filtration efficiency of 90.1%, and a filtration resistance of 17.9 Pa.

[0039] Example 7

[0040] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene succinate (PEB) accounts for 10%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 195°C, a melt index of 153g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 3.2s.

[0041] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 5.3 μm, an MD tensile force of 29 N, and an MD elongation of 37%; a TD tensile force of 26 N, and a TD elongation of 30%; a filtration efficiency of 98.6%, and a filtration resistance of 33.5 Pa.

[0042] Example 8

[0043] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene glycol glutarate (PEG) accounts for 10%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 193°C, a melt index of 155g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 3.4s.

[0044] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 5.1 μm, an MD tensile force of 30 N, and an MD elongation of 38%; a TD tensile force of 28 N, and a TD elongation of 33%; a filtration efficiency of 98.8%, and a filtration resistance of 34.1 Pa.

[0045] Reference example 1

[0046] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 76%, isophthalic acid accounts for 12%, and polyethylene adipate accounts for 12%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 186°C, a melt index of 162g / 10min, and no obvious melting crystallization peak of the polyester.

[0047] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 61 g / m2, a fiber diameter of 8.2 μm, an MD tensile force of 61 N, and an MD elongation of 93%; a TD tensile force of 15 N, and a TD elongation of 3%; a filtration efficiency of 69.3%, and a filtration resistance of 11.5 Pa.

[0048] Reference example 2

[0049] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 96%, isophthalic acid accounts for 2%, and polyethylene adipate accounts for 2%. The molar ratio of ethylene glycol to the total of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 240°C, a melt index of 123g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 2.0s.

[0050] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material has a gram weight of 60 g / m2, a fiber diameter of 5.5 μm, an MD tensile force of 25 N, and an MD elongation of 5%; a TD tensile force of 14 N, and a TD elongation of 3%; a filtration efficiency of 97.5%, and a filtration resistance of 25.6 Pa.

[0051] Reference example 3

[0052] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene adipate accounts for 10%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 50min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.40dL / g, a Tm of 190°C, a melt index of 230g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 2.1s.

[0053] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 5.4 μm, an MD tensile force of 12 N, and an MD elongation of 33%; a TD tensile force of 21 N, and a TD elongation of 42%; a filtration efficiency of 95.5%, and a filtration resistance of 30.2 Pa.

[0054] Reference example 4

[0055] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 10%, and polyethylene adipate accounts for 10%. The molar ratio of ethylene glycol to the total of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 60min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.45dL / g, a Tm of 190°C, a melt index of 200g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 2.1s.

[0056] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 61 g / m2, a fiber diameter of 8.5 μm, an MD tensile force of 10 N, and an MD elongation of 12%; a TD tensile force of 13 N, and a TD elongation of 2%; a filtration efficiency of 67.2%, and a filtration resistance of 14.3 Pa.

[0057] Reference example 5

[0058] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 80%, isophthalic acid accounts for 15%, and polyethylene adipate accounts for 5%. The molar ratio of ethylene glycol to the total of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 188°C, a melt index of 162g / 10min, and a half-crystallization period t1 / 2 of melt crystallization of 4.8s.

[0059] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material had a gram weight of 60 g / m2, a fiber diameter of 6.9 μm, an MD tensile force of 15 N, and an MD elongation of 37%; a TD tensile force of 16 N, and a TD elongation of 33%; a filtration efficiency of 84.5%, and a filtration resistance of 22.4 Pa.

[0060] Reference example 6

[0061] The total mass of terephthalic acid, isophthalic acid, and aliphatic dibasic acid ethylene glycol ester in the synthetic raw materials of melt-blown polyester is 100%, terephthalic acid accounts for 75%, isophthalic acid accounts for 20%, and polyethylene adipate accounts for 5%. The molar ratio of ethylene glycol to the sum of terephthalic acid and isophthalic acid is 1.2. The catalyst is ethylene glycol antimony, in which antimony atoms account for 200ppm of the total polyester mass. The conventional esterification reaction is carried out at 256°C by direct esterification-melt polycondensation method. After the esterification is completed, the polycondensation reaction is carried out at 283°C and the absolute pressure is below 100Pa for 70min. After the reaction is completed, the melt-blown polyester is obtained by extrusion, drawing, pelletizing, and drying. The polyester has a characteristic viscosity of 0.50dL / g, a Tm of 176°C, a melt index of 180g / 10min, and no obvious melting crystallization peak of the polyester.

[0062] After the melt-blown polyester chips were dried, the non-woven filter material was prepared by a melt-blown device. The number of spinneret holes used was 2600, the pore size was 0.32 mm, and the melt-blown non-woven filter material was prepared under the conditions of screw extrusion temperature of 290°C, die temperature of 290°C, hot air temperature of 295°C, hot air volume of 27%, and DCD of 100 mm. The prepared melt-blown non-woven filter material has a gram weight of 60 g / m2, a fiber diameter of 7.9 μm, an MD tensile force of 11 N, and an MD elongation of 40%; a TD tensile force of 11 N, and a TD elongation of 42%; a filtration efficiency of 65.3%, and a filtration resistance of 11 Pa.

[0063] Test method:

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

[0065] Melting point: DSC (differential scanning calorimetry) method was used for testing. Under nitrogen protection, the temperature was raised from 25°C to 290°C at a heating rate of 10°C / min. After keeping the temperature constant for 5 minutes, the temperature was lowered from 290°C to 25°C at a cooling rate of 10°C / min. The DSC curve of polyester was obtained to determine the melting point of the product.

[0066] Melting semi-crystallization period t1 / 2: DSC method was used for testing. Under nitrogen protection, the temperature was raised from 25°C to 290°C at a heating rate of 10°C / min. After keeping the temperature constant for 5 minutes, the temperature was lowered from 290°C to 25°C at a cooling rate of 10°C / min to obtain the DSC curve of polyester. The melting semi-crystallization period t1 / 2 was calculated by the Jeziomy model for the melting crystallization part curve.

[0067] Melt index: The national standard GB / T 3682.1-2018 "Determination of melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic plastics" is adopted. The test temperature is 260℃ and the load is 2.16kg.

[0068] Table 1

[0069]

[0070]

[0071] Table 2

[0072]

[0073] The test results of the embodiments and reference examples of the present invention are listed in Table 1. The present invention prepares a PET material for meltblowing by composite modification of aliphatic monomers and polar aromatic monomers, and realizes the preparation of PET meltblown cloth filter material by meltblowing equipment. The present invention defines the intrinsic viscosity, melting point, melt index and semi-crystallization period of melt crystallization of the PET meltblown material, and evaluates the fiber diameter, mechanical properties and filtration performance of the prepared meltblown cloth material.

[0074] The influence mechanism of polyester material on the performance of meltblown cloth is as follows:

[0075] The intrinsic viscosity and melting point of polyester will have a comprehensive impact on the melt index of polyester. When the melt index of polyester is too low, the melt-blown component pressure will be too high, the spinning will be poor, and it will be difficult to form a cloth. At the same time, the performance indicators of polyester such as the content of modified components, melting point, melt index, and melting semi-crystallization period will have a comprehensive impact on the performance of the filter material. Therefore, the performance of the final filter material cannot be measured or predicted by a single indicator. The modified components of polyester can reduce the melt index and melting point of polyester, thereby reducing the pressure of melt-blown components and the difficulty of melt-blowing. At the same time, the melting point of polyester is reduced and the melting semi-crystallization period of polyester is prolonged, which can improve the thermal bonding effect between melt-blown filaments and improve the mechanical properties of filter materials. However, the modified components will increase the diameter of polyester filaments, resulting in poor filtering effect of filter materials. At the same time, too high content of modified components will cause the melting crystallization semi-crystallization period of polyester to be too short or disappear, which will reduce the mechanical properties of filter materials. The intrinsic viscosity of polyester directly affects the melting index of polyester. The higher the intrinsic viscosity, the smaller the melting index. The melting point of polyester mainly affects the melting index of polyester and the thermal bonding effect between melt-blown filaments. Reducing the melting point can effectively improve the mechanical properties of filter materials. The melting index of polyester reflects the flow properties of polyester melt, directly affects the melt-blowing process and the fabrication performance of melt-blown cloth. The improvement of the melting index is beneficial to improving the mechanical properties and filtering effect of filter materials. The melting crystallization semi-crystallization period of polyester reflects the crystallization performance of polyester. The longer the semi-crystallization period, the slower the crystallization, which is beneficial to melt-blown cloth, but too slow crystallization will also reduce the mechanical properties of filter materials. The diameter of the meltblown wire directly affects the size of the gaps on the filter material surface. The smaller the diameter of the meltblown wire is, the better the filtration effect is and the greater the filtration resistance is.

[0076] In the present invention, compared with reference examples 1, 5, and 6, when the polyester modified component is more than the scope of the present invention, although the melt index is higher, the melt-blown filament bundle diameter is larger, and the final filter material has a poor filtering effect; and the polyester melt crystallization semi-crystallization period is too long, the crystallization is slow, the MD and TD direction tension is small, and the mechanical strength is poor. Compared with reference example 2, when the polyester modified component content is lower than the scope of the present invention, the polyester melting point is higher, the melt index is lower, the bonding effect between the melt-blown filament bundles is poor, and the elongation in the MD and TD directions of the final filter material is shorter, and the tensile performance is poor. Compared with reference example 3, when the polyester characteristic viscosity is lower than the scope of the present invention, although the melt index is higher, the polyester melt semi-crystallization period is short, the crystallization is fast, the bonding effect between the melt-blown filament bundles is poor, the final filter material has a poor cloth-forming effect, the MD and TD direction tension is small, and the mechanical strength is poor. Compared with Reference Example 4, when the characteristic viscosity of the polyester is higher than the range of the present invention, the polyester melt index is low, the diameter of the meltblown filament bundle becomes coarser, the filtration effect becomes worse, and the bonding effect between the filament bundles becomes worse, and the final filtration effect and mechanical properties of the filter material are significantly reduced.

Claims

1. A polyester for meltblowing, characterized in that: The polyester contains aliphatic dibasic acid ethylene glycol ester, and the intrinsic viscosity of the polyester is 0.45-0.6 dL·g -1 The melting point of polyester is between 190 and 230°C.

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

3. The melt-blown polyester according to claim 1, characterized in that: Melt crystallization half-crystallization period t of meltblown polyester 1 / 2 Between 2.5 and 4.0 seconds.

4. The polyester for meltblowing according to claim 1, characterized in that: Polyester is made from terephthalic acid, isophthalic acid, aliphatic dibasic acid ethylene glycol esters and ethylene glycol.

5. The polyester for meltblowing according to claim 4, characterized in that: If the total mass of terephthalic acid, isophthalic acid and aliphatic dibasic acid glycol ester in the raw materials is 100%, then terephthalic acid accounts for 80%-90%, isophthalic acid accounts for 5%-10%, and polyaliphatic dibasic acid glycol ester accounts for 5%-10%.

6. The polyester for meltblowing according to claim 4, characterized in that: The molar ratio of the diol to the dibasic acid in the raw material is 1-1.5:1, the diol is ethylene glycol, and the dibasic acid is terephthalic acid and isophthalic acid.

7. The polyester for meltblowing according to claim 4, characterized in that: The poly(ethylene glycol) ester of aliphatic dibasic acid may be one or more of poly(ethylene glycol) malonate, poly(ethylene glycol) succinate, poly(ethylene glycol) glutarate, poly(ethylene glycol) adipate, poly(ethylene glycol) suberate and the like.

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

9. The preparation method according to claim 8, characterized in that: The catalyst used in the direct esterification-melt polycondensation method is ethylene glycol antimony, and the antimony atoms account for 100-300 ppm of the total polyester mass; the temperature of the esterification reaction is 250-260°C, the temperature of the polycondensation reaction is 280-285°C, the time of the polycondensation reaction is 70-90 minutes, and the pressure of the polycondensation reaction is below 100 Pa absolute pressure.

10. A non-woven filter material, characterized in that: The non-woven filter cloth is prepared by drying the melt-blown polyester chips of claim 1 and passing them through a melt-blown device; the material has a gram weight of 60 g / m 2 When the MD tension is 21-30N, the MD elongation is 29-52%, the TD tension is 20-28N, and the TD elongation is 20-44%. The melt-blown filament diameter is 4.8-6.9μm, the filtration efficiency is 92.3-99%, and the filtration resistance is 17.9-34.9Pa.

Images