CN116555940A - A kind of preparation method of flame-retardant regenerated polyester fiber - Google Patents

Abstract

The invention discloses a preparation method of flame-retardant regenerated polyester fiber, which belongs to the technical field of flame-retardant fibers. The method includes the preparation of flame-retardant recycled polyester masterbatch, and the dried waste polyester bottle flakes and flame-retardant masterbatch are melt-blended and spun, passed through the spinneret assembly, sprayed and extruded, cooled by surrounding air, clustered and oiled, and drawn. Stretching, heat setting and winding to prepare flame retardant recycled polyester fibers. The invention uses the treated waste polyester bottle flakes as the base polyester to prepare a reactive flame-retardant recycled polyester masterbatch, which solves the problem of poor compatibility between the flame retardant and the base polyester, and realizes the recycling of waste bottle flakes. Recycled and used in the preparation of flame-retardant polyester fibers, the prepared polyester fibers have excellent flame-retardant properties.

Description

A kind of preparation method of flame-retardant regenerated polyester fiber

technical field

The invention belongs to the technical field of flame-retardant fibers, and in particular relates to a preparation method of flame-retardant regenerated polyester fibers.

Background technique

Polyester fiber has the advantages of low cost, high strength, and good decontamination performance. It is widely used in clothing fabrics and other fields. It is currently the most used polyester material in the world. However, on the one hand, a large amount of waste polyester materials have accumulated in the environment, causing serious environmental pollution. On the other hand, the limiting oxygen index (LOI) of polyester fibers is only 20% to 22%, which is a flammable fiber, so it is not suitable for waste and old materials. The recycling of polyester and the flame retardant modification of polyester materials are of great significance.

At present, there are mainly two methods for flame retardant modification of polyester fibers: blending and copolymerization. The blending method is to prepare flame-retardant polyester fibers by melt-blending and spinning flame retardants and polyester chips. Patent CN112663167A discloses a kind of flame retardant polyester fiber and its preparation method, the method includes the preparation of masterbatch and the masterbatch and polyester chips to prepare flame retardant polyester fiber by melt blending and spinning, the masterbatch is composed of inorganic nanoparticles, containing Fluorine flame retardant, dispersant, coupling agent, antioxidant and polyester matrix are prepared by melt blending. The polyester fiber provided by the invention has flame retardant effect. The blending method mainly has the problems of poor compatibility between the flame retardant and the matrix polyester, and the flame retardant is easy to agglomerate and precipitate. The copolymerization method is to introduce flame retardant elements into the polyester molecular chain by adding reactive flame retardant monomers in the polycondensation stage to prepare polyester fiber products with long-lasting flame retardancy and low toxicity. Patent CN115679470A discloses a flame-retardant fiber fabric and its preparation method. The synthetic new-type dicarboxytriazine phosphate is used as a flame retardant to undergo transesterification and polycondensation reactions with dimethyl terephthalate and ethylene glycol. The triazine phosphate flame retardant is grafted into the PET polyester molecular chain, and finally the flame retardant polyester fiber fabric is obtained through spinning and manufacturing. The flame-retardant polyester fiber fabric provided by the invention has flame-retardant effect. Patent CN105463610 discloses a flame-retardant polyester fiber and its preparation method. The flame-retardant polyester fiber is prepared by copolymerizing 2-carboxyethylphenyl hypophosphorous acid as a flame retardant with a polyester monomer, and then the double fiber is opened by ultraviolet light irradiation. Bonds form cross-linking points and form a certain network structure to improve its flame retardant performance. The flame-retardant polyester fiber provided by the invention has good flame-retardant effect. The blending method solves the problem of poor compatibility between the flame retardant and the matrix polyester. The flame retardant is not easy to migrate and precipitate, and has good long-lasting flame retardancy. However, the processing technology is relatively complicated, the cost is high, and the industrial application is limited.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art, thereby providing a method for preparing flame-retardant recycled polyester fibers, which is different from the method of directly adding flame retardants to recycled polyester chips to prepare masterbatches. The present invention Firstly, the waste PET bottle flakes are subjected to chain scission treatment through micro-alcoholysis and depolymerization technology, and then the flame retardant is introduced into the molecular chain of the recycled polyester, and at the same time, a synergistic flame retardant additive is added to blend with it, and the preparation has good compatibility. and durable flame retardant flame retardant recycled polyester masterbatch.

The technical solution adopted by the present invention to solve its technical problems is:

A preparation method of flame-retardant regenerated polyester fiber, comprising the steps of:

S1: Put the dried waste polyester bottle flakes into the screw extruder for melting, add ethylene glycol during the melting process of the waste polyester bottle flakes, and melt the waste polyester bottle flakes under the mechanical stirring of the screw. The polyester melt is fully mixed with ethylene glycol, and then the small molecular substances in the fully mixed polyester melt are removed by vacuuming, and then phenyl-ethylene glycol propionate-based phosphinic acid is added to the screw extruder Perform polymerization reaction to obtain recycled polyester melt with moderate intrinsic viscosity, add hexagonal boron nitride to the recycled polyester melt in the screw extruder, and obtain flame-retardant recycled polyester masterbatch through screw extrusion and granulation;

S2: The flame-retardant recycled polyester masterbatch prepared above and waste polyester bottle flakes are melt-blended and spun according to a certain feeding ratio. The preparation steps of drawing, heat setting and winding obtain flame-retardant regenerated polyester fibers.

Preferably, in the step S1, the drying method of the waste polyester bottle flakes comprises: first placing the waste polyester bottle flakes in an oven to dry for 2 to 3 hours at a temperature of 120°C, and then taking them out and placing them in a vacuum oven Dry at 150°C for 4-6 hours.

Preferably, in the step S1, the mass ratio of ethylene glycol to waste polyester flakes is 0.01-0.1:100; the mass ratio of phenyl-ethylene glycol propionate-based phosphinic acid to waste polyester flakes 0.05-0.5:100; the mass ratio of hexagonal boron nitride to waste PET bottle flakes is 1-10:100.

Preferably, in the step S1, a slight alcoholysis reaction occurs during the mixing process of waste polyester bottle flakes and ethylene glycol, and the time of the slight alcoholysis reaction is kept at 10-20min. After the slight alcoholysis reaction, the polyester melt The intrinsic viscosity is 0.70～1.20dL/g.

Preferably, in the step S2, the intrinsic viscosity of the regenerated polyester melt with moderate intrinsic viscosity is 0.70-1.30 dL/g.

Preferably, in the steps S1-S3, the screw extruder is equipped with six heating zones, and the processing temperatures of each heating zone are respectively: 180-200°C in the first zone, 200-220°C in the second zone, and 220-220°C in the third zone. 240°C, 240-260°C in the fourth zone, 260-280°C in the fifth zone, and 260-280°C in the sixth zone.

Preferably, in the step (2), the mass ratio of recycled polyester masterbatch to waste polyester bottle flakes is 1-5:20.

Preferably, in the step (2), the temperature in the melt-blending spinning process is 270-290°C, the wind temperature in the ring blowing process is 25-30°C, and the wind speed in the ring blowing process is 0.3-0.5m/min The stretching ratio is 2.7-3.5 times, the temperature in the stretching process is 145-165°C, the temperature in the heat setting process is 135-150°C, and the winding speed is 4000-4500m/min.

Compared with the prior art, the present invention has the following advantages and effects: using waste polyester bottle flakes as matrix polyester, first prepare a reactive flame-retardant recycled polyester masterbatch, and then melt it with waste polyester bottle flakes Preparation of flame retardant polyester fiber by blend spinning. It not only solves the problem of poor compatibility between the flame retardant and the matrix polyester, and the problem that the flame retardant is easy to agglomerate, but also realizes the recycling of waste polyester bottle flakes.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below in conjunction with specific examples and comparative examples. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terminology used herein in the description of the present invention is only for the purpose of describing specific embodiments, and is not intended to limit the present invention.

Example 1.

This embodiment provides a method for preparing a flame-retardant recycled polyester fiber, the preparation method comprising the following steps:

S1: Dry waste polyester bottle flakes in an oven at 120°C for 2.5 hours, then dry them in a vacuum oven at 150°C for 5 hours, and then add them to the screw extruder to melt them. The polyester melt produced by melting waste polyester bottle flakes is fully mixed with EG, the melting temperature of the screw extruder is kept at 190°C, the slight alcoholysis time is kept at 15min, and small molecular substances are removed by vacuuming. Add CEPPA to the mouth, keep the temperature of the screw extruder at 270°C, add h-BN to the recycled polyester melt, and extrude and granulate to obtain flame-retardant recycled polyester masterbatch;

S2: Melt blending and spinning the flame-retardant recycled polyester masterbatch prepared above and waste polyester bottle flakes, extrude through the spinneret assembly, cool with the surrounding air, cluster oiling, drafting, heat setting and coiling Flame retardant regenerated polyester fibers were prepared by winding. Among them, the melt blending spinning temperature is 280°C, the air temperature of the surrounding blower is 27°C, and the wind speed of the surrounding blowing is 0.4m/min; the draw ratio is 3.0 times, the stretching temperature is 155°C, the heat setting temperature is 145°C, and the winding speed It is 4500m/min.

The mass ratio of EG to PET bottle flakes is 0.01:100, the mass ratio of CEPPA to PET bottle flakes is 0.05:100, the mass ratio of h-BN to PET bottle flakes is 1:20, and the recycled polyester masterbatch and PET bottle The film mass ratio is 1:20.

Example 2.

This embodiment provides a method for preparing a flame-retardant recycled polyester fiber, the preparation method comprising the following steps:

S1: Dry waste polyester bottle flakes in an oven at 120°C for 2.5 hours, then dry them in a vacuum oven at 150°C for 5 hours, and then add them to the screw extruder to melt them. The polyester melt produced by melting waste polyester bottle flakes is fully mixed with EG, the melting temperature of the screw extruder is kept at 190°C, the slight alcoholysis time is kept at 15min, and small molecular substances are removed by vacuuming. Add CEPPA to the mouth, keep the temperature of the screw extruder at 270°C, add h-BN to the recycled polyester melt, and extrude and granulate to obtain flame-retardant recycled polyester masterbatch;

S2: Melt blending and spinning the flame-retardant recycled polyester masterbatch prepared above and waste polyester bottle flakes, extrude through the spinneret assembly, cool with the surrounding air, cluster oiling, drafting, heat setting and coiling Flame retardant regenerated polyester fibers were prepared by winding. Among them, the melt blending spinning temperature is 280°C, the air temperature of the surrounding blower is 27°C, and the wind speed of the surrounding blowing is 0.4m/min; the draw ratio is 3.0 times, the stretching temperature is 155°C, the heat setting temperature is 145°C, and the winding speed It is 4500m/min.

The mass ratio of EG to PET bottle flakes is 0.01:100, the mass ratio of CEPPA to PET bottle flakes is 0.05:100, the mass ratio of h-BN to PET bottle flakes is 1:20, and the recycled polyester masterbatch and PET bottle The film mass ratio is 1:10.

Example 3.

This embodiment provides a method for preparing a flame-retardant recycled polyester fiber, the preparation method comprising the following steps:

S1: Dry waste polyester bottle flakes in an oven at 120°C for 2.5 hours, then dry them in a vacuum oven at 150°C for 5 hours, and then add them to the screw extruder to melt them. The polyester melt produced by melting waste polyester bottle flakes is fully mixed with EG, the melting temperature of the screw extruder is kept at 190°C, the slight alcoholysis time is kept at 15min, and small molecular substances are removed by vacuuming. Add CEPPA to the mouth, keep the temperature of the screw extruder at 270°C, add h-BN to the recycled polyester melt, and extrude and granulate to obtain flame-retardant recycled polyester masterbatch;

S2: Melt blending and spinning the flame-retardant recycled polyester masterbatch prepared above and waste polyester bottle flakes, extrude through the spinneret assembly, cool with the surrounding air, cluster oiling, drafting, heat setting and coiling Flame retardant regenerated polyester fibers were prepared by winding. Among them, the melt blending spinning temperature is 280°C, the air temperature of the surrounding blower is 27°C, and the wind speed of the surrounding blowing is 0.4m/min; the draw ratio is 3.0 times, the stretching temperature is 155°C, the heat setting temperature is 145°C, and the winding speed It is 4500m/min.

The mass ratio of EG to PET bottle flakes is 0.01:100, the mass ratio of CEPPA to PET bottle flakes is 0.05:100, the mass ratio of h-BN to PET bottle flakes is 1:20, and the recycled polyester masterbatch and PET bottle The film mass ratio is 1:4.

Performance Testing.

Characterize the performance of the flame-retardant regenerated polyester fiber obtained in the above examples, and the specific test items, test methods and results are shown in Table 1:

Fiber mechanical performance test: standard GB/T 14344-2022 test method for tensile properties of chemical fiber filaments, in which the specific test conditions are: the pre-tension value is set to 5 cN, the clamping length is set to 250 mm, and the tensile rate is set to It is 250mm/min, and each group of fiber samples is tested 10 to 20 times until a stable data is obtained, and the CV value is required to be kept within 15%.

Oxygen index measurement: according to GB/T2406-2009 standard test, wherein the specific test conditions are: sample size 120X6.5X3mm. Under the specified test conditions, the sample maintains stable combustion in the oxygen-nitrogen mixed gas flow (that is, the lowest volume percentage concentration of oxygen in the mixed gas required to keep burning 50mm long or burning for 3 minutes);

Vertical combustion measurement: according to the GB/T2408-2008 standard test, the specific test conditions are: the sample size is 130X13mm, ignited for 10 minutes, the fire source is removed, and the flame burning time is recorded. If it self-extinguishes within 30 minutes, the flame burning is recorded time and flameless burn time.

The test result of the flame-retardant regenerated polyester fiber that the embodiment of table 1 obtains

performance Tensile strength/MPa Breaking strength/MPa Limiting Oxygen Index/% vertical burn rating Example 1 680 720 30 V0 Example 2 652 689 33 V0 Example 3 626 640 33 V0

From the above results it can be seen that:

By selecting the formula of the present invention, the prepared flame-retardant recycled polyester masterbatch has excellent performance, and with the increase of the added amount of flame retardant, the limiting oxygen index and vertical combustion grade are all improved, and the flame-retardant performance is improved. Among them, the vertical combustion grades of the recycled flame-retardant polyester materials in the examples of the present invention can all reach V-0 grades, and the limiting oxygen indexes are all above 30%.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

Auxiliary information and suppliers used in the above examples and comparative examples are as follows:

Waste polyester bottle flakes are made from waste polyester bottles after sorting, cutting, cleaning and drying;

The manufacturer of the polyester bottle body is DuPont of the United States, and the intrinsic viscosity is 1.0dL/g;

The manufacturer of ethylene glycol is Jinan Jinquan Chemical Co., Ltd., and the grade is analytically pure;

The manufacturer of hexagonal boron nitride is Shanghai McLean Biochemical Technology Co., Ltd., and the grade is analytically pure;

The manufacturer of phenyl-propionic acid ethylene glycol ester phosphinic acid is Jinan Jinquan Chemical Co., Ltd., and the grade is analytically pure.

It should be noted that the above auxiliaries are only to illustrate the source and composition of the auxiliaries in various examples and comparative examples, so that the technical solution is clearer, and can not be used to limit the protection scope of the present invention, and other similar reagents are used Or reagents provided by other suppliers, or auxiliary agents with different parameters can realize the present invention.

The above content described in this specification is only an illustration of the present invention. Those skilled in the technical field to which the present invention belongs may make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, as long as they do not deviate from the content of the description of the present invention or exceed the scope defined in the claims , should belong to the protection scope of the present invention.

Claims (8)

1. a preparation method of flame-retardant regenerated polyester fiber, is characterized in that, comprises the steps: S1: Put the dried waste polyester bottle flakes into the screw extruder for melting, add ethylene glycol during the melting process of the waste polyester bottle flakes, and melt the waste polyester bottle flakes under the mechanical stirring of the screw. The polyester melt is fully mixed with ethylene glycol, and then the small molecular substances in the fully mixed polyester melt are removed by vacuuming, and then phenyl-ethylene glycol propionate-based phosphinic acid is added to the screw extruder Perform polymerization reaction to obtain recycled polyester melt with moderate intrinsic viscosity, add hexagonal boron nitride to the recycled polyester melt in the screw extruder, and obtain flame-retardant recycled polyester masterbatch through screw extrusion and granulation; S2: The flame-retardant recycled polyester masterbatch prepared above and waste polyester bottle flakes are melt-blended and spun according to a certain feeding ratio. The preparation steps of drawing, heat setting and winding obtain flame-retardant regenerated polyester fibers. 2. according to the preparation method of the described flame-retardant regenerated polyester fiber of claim 1, it is characterized in that, in described step S1, the drying method of waste polyester bottle flakes comprises: first place waste polyester bottle flakes in oven Dry at a temperature of 120°C for 2 to 3 hours, then take it out and place it in a vacuum oven to dry at a temperature of 150°C for 4 to 6 hours. 3. The preparation method of flame-retardant regenerated polyester fiber according to claim 1, characterized in that: in the step S1, the mass ratio of ethylene glycol to waste polyester bottle flakes is 0.01-0.1:100; phenyl- The mass ratio of ethylene glycol propionate-based phosphinic acid to waste polyester bottle flakes is 0.05-0.5:100; the mass ratio of hexagonal boron nitride to waste polyester bottle flakes is 1-10:100. 4. The preparation method of flame-retardant regenerated polyester fiber according to claim 1, characterized in that: in the step S1, slight alcoholysis reaction can occur in the mixing process of waste polyester bottle flakes and ethylene glycol, and the slight alcoholysis The hydrolysis reaction time is kept at 10-20 minutes, and the intrinsic viscosity of the polyester melt after the slight alcoholysis reaction is 0.70-1.20 dL/g. 5 . The method for preparing flame-retardant regenerated polyester fiber according to claim 1 , characterized in that: in the step S2 , the regenerated polyester melt with a moderate intrinsic viscosity has an intrinsic viscosity of 0.70-1.30 dL/g. 6. according to the preparation method of the described flame-retardant regenerated polyester fiber of claim 1, it is characterized in that: in described step S1-S3, screw extruder is provided with six heating zones altogether, and the processing temperature of each heating zone is respectively : Zone 1 180-200℃, Zone 2 200-220℃, Zone 3 220-240℃, Zone 4 240-260℃, Zone 5 260-280℃, Zone 6 260-280℃. 7. The preparation method of flame-retardant regenerated polyester fiber according to claim 1, characterized in that: in the step (2), the mass ratio of regenerated polyester masterbatch to waste polyester bottle flakes is 1-5: 20. 8. The preparation method of flame-retardant regenerated polyester fiber according to claim 1, characterized in that: in the step (2), the temperature in the melt-blending spinning process is 270-290°C, and the air temperature in the ring blowing process is 270-290°C. 25～30℃, the wind speed in the process of ring blowing is 0.3～0.5m/min; the stretching ratio is 2.7～3.5 times, the temperature in the stretching process is 145～165℃, and the temperature in the heat setting process is 135～ 150°C, the winding speed is 4000-4500m/min.