A method for preparing flame-retardant reinforced recycled polyester fiber

Abstract

The invention discloses a reinforced flame-retardant regenerated polyester fiber and a preparation method thereof, and relates to the technical field of regenerated polyester fibers, comprising the following steps: step S1, using bis(4-carboxylphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, and N-(4H-1,2,4-triazole-4-yl)diphenylamine-4,4'-dicarboxylic acid as monomers to prepare a flame-retardant polymer; step S2, preparing a flame-retardant masterbatch; step S3, spinning; step S4, using (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt for surface modification. The reinforced flame-retardant regenerated polyester fiber has good mechanical properties, good flame retardancy, excellent heat aging resistance and environmental protection.

Description

Technical Field

[0001] The invention relates to the technical field of regenerated polyester fibers, and in particular to a reinforced flame-retardant regenerated polyester fiber and a preparation method thereof. Background Art

[0002] Recycled polyester is made from recycled polyester bottles, filament waste or waste fabrics, and is a recycling of polyester waste. With the increase in polyester consumption and the enhancement of people's environmental awareness, the recycling of polyester waste has received more and more attention. Using polyester waste to produce recycled polyester fiber can reduce costs, reduce oil consumption and improve economic benefits.

[0003] Compared with PET, recycled polyester chips have their own characteristics, such as high impurity content, wide molecular weight distribution, and large viscosity range, which make spinning more difficult. Recycled polyester fibers made by current conventional methods still have more or less technical defects such as insufficient strength, insufficient flame retardancy, and environmental protection and heat aging resistance need to be further improved.

[0004] In order to solve the above problems, the Chinese invention patent with the authorization announcement number CN103215686B discloses a method for preparing halogen-free flame-retardant regenerated polyester fiber, and the specific steps are: drying the flame retardant powder; mixing the dried regenerated polyester with the flame retardant powder, injecting the obtained mixture into a twin-screw extruder for extrusion granulation to form a flame-retardant regenerated polyester masterbatch; mixing the regenerated polyester chips with the flame-retardant regenerated polyester masterbatch obtained in the second step, drying, cooling, adding a dispersant to obtain a spinning raw material, adding the spinning raw material to a composite spinning machine for spinning, and obtaining the primary flame-retardant fiber, and then post-drawing processing to obtain a flame-retardant regenerated polyester fiber. The flame-retardant regenerated polyester chips provided by the invention have good spinning molding and excellent fiber quality; the amount of flame retardant used is small, the cost is low, and the fiber performance is effectively improved. However, the heat aging resistance of the regenerated polyester fiber still needs to be further improved.

[0005] It can be seen that the development of a reinforced flame-retardant recycled polyester fiber with good mechanical properties, good flame retardancy, excellent heat aging resistance and environmental protection and its preparation method meets market demand, has broad market demand and application prospects, and is of great significance to promoting the development of the recycled polyester fiber field. Summary of the invention

[0006] In order to overcome the defects in the prior art, the present invention provides a reinforced flame-retardant regenerated polyester fiber with good mechanical properties, good flame retardancy, excellent heat aging resistance and environmental protection, and a preparation method thereof.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing a reinforced flame-retardant recycled polyester fiber, comprising the following steps:

[0008] Step S1, preparation of flame-retardant polymer: bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, a catalyst and a high boiling point solvent are mixed uniformly and added into a high-pressure reactor, and the air in the reactor is replaced by an inert gas, followed by stirring and reacting at 130-140° C. under normal pressure for 2-4 hours, then reducing the pressure to 10-100 Pa, raising the temperature to 245-275° C., stirring and reacting for 15-22 hours while maintaining the temperature and pressure, cooling to room temperature after the reaction is completed, precipitating in water, washing the precipitated polymer with ethanol for 3-6 times, and finally drying in a vacuum dryer at 85-95° C. to constant weight to obtain a flame-retardant polymer;

[0009] Step S2, preparation of flame retardant masterbatch: the flame retardant polymer, coupling agent and inorganic filler prepared in step S1 are mixed evenly, added into a twin-screw extruder for melt blending and extrusion, and pelletized to obtain flame retardant masterbatch;

[0010] Step S3, spinning: the flame retardant masterbatch prepared in step S2, the recycled polyester, the antioxidant, and the lubricant are uniformly mixed to obtain a spinning raw material, which is then added to a composite spinning machine for spinning after drying, and then subjected to a drafting process to obtain a primary recycled polyester fiber;

[0011] Step S4, surface modification: (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt are uniformly dispersed in an organic solvent to form a dispersion, which is uniformly sprayed on the surface of the regenerated polyester fiber, and then heated under a nitrogen atmosphere by using 60 The fiber is radiated by a Co-γ-ray source, and then washed and dried to obtain the reinforced flame-retardant recycled polyester fiber.

[0012] Preferably, the molar ratio of bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst and high boiling point solvent in step S1 is 0.7:1:0.3:(0.8-1.2):(6-10).

[0013] Preferably, the catalyst is a mixture of antimony ethylene glycol, tetrabutyl titanate, and p-toluenesulfonic acid in a mass ratio of (1-2):0.8:(0.8-1.2).

[0014] Preferably, the high boiling point solvent is dimethyl sulfoxide; the inert gas is any one of nitrogen, helium, neon and argon.

[0015] Preferably, the mass ratio of the flame retardant polymer, the coupling agent and the inorganic filler is 100:(3-5):(10-20).

[0016] Preferably, the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0017] Preferably, the inorganic filler is a mixture of nano boron fiber and light calcium carbonate in a mass ratio of 1:(1-2); the average diameter of the nano boron fiber is 30-90 nm and the length is 3-6 microns; the particle size of the light calcium carbonate is 1000-1500 mesh.

[0018] Preferably, the temperature of the melt blending extrusion in step S2 is 240-260° C., and the extrusion pressure is 5-10 MPa.

[0019] Preferably, the mass ratio of the flame retardant masterbatch, recycled polyester, antioxidant and lubricant in step S3 is (4-8):1:(0.8-1):0.5.

[0020] Preferably, the recycled polyester in step S3 is made from recycled polyester bottle flakes that are sequentially sorted, crushed, cleaned and dried.

[0021] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0022] Preferably, the lubricant is at least one of pentaerythritol stearate and ethylene bisstearamide.

[0023] Preferably, the spinning temperature is 250-290° C., and the spinning winding speed is 800-2400 m / min.

[0024] Preferably, the drawing processing parameters are a drawing multiple of 1.5-4 times, a hot plate temperature of 65-95°C, and a hot plate temperature of 115-205°C.

[0025] Preferably, the mass ratio of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, organic solvent, and regenerated polyester fiber in step S4 is 1:(0.8-1.2):(6-10):80.

[0026] Preferably, the organic solvent is toluene.

[0027] Preferably, the radiation grafting is carried out at room temperature, with an absorbed dose of 10 to 45 kGy and a dose rate of 10 to 20 kGy / h.

[0028] Another object of the present invention is to provide a reinforced flame retardant regenerated polyester fiber prepared by the above-mentioned method for preparing the reinforced flame retardant regenerated polyester fiber.

[0029] The beneficial effects of adopting the above technical solution are:

[0030] (1) The preparation method of the reinforced flame-retardant regenerated polyester fiber provided by the present invention has a simple production process, low energy consumption, convenient operation, and is suitable for mass production. The mechanical properties and flame retardant properties of the polyester fiber can be effectively changed by changing the addition amount of the flame retardant masterbatch.

[0031] (2) The reinforced flame-retardant regenerated polyester fiber provided by the present invention adopts a flame-retardant polymer and an inorganic filler as the flame-retardant active ingredient, which not only has excellent flame-retardant activity, but is also halogen-free, non-toxic, and environmentally friendly. By first making a flame-retardant masterbatch and then blending it with recycled polyester for spinning, the compatibility and dispersion uniformity between the components can be effectively improved, thereby effectively improving the mechanical properties and performance stability of the product.

[0032] (3) The flame-retardant reinforced regenerated polyester fiber provided by the present invention is a flame-retardant polymer prepared by polycondensation of bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, and N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, forming a polyester-type polymer having good compatibility with the regenerated polyester. Phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decane, and phenyltriazole structures are simultaneously introduced into the molecular chain. In the surface modification stage, Radiation grafting introduces perfluoropropane structure and amphoteric organic ion salt structure. Under the multiple effects of electronic effect, steric effect and conjugation effect, these structures and groups make the manufactured polyester fiber products have good mechanical properties, good flame retardancy, excellent heat aging resistance and environmental protection. (Perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate is a di-active functional group substance. During the radiation grafting stage, it can form an interpenetrating network cross-linked structure on the surface of polyester fibers, thereby further improving the mechanical properties, flame retardancy and heat aging resistance. DETAILED DESCRIPTION

[0033] In order to make the technical solution of the present invention better understood by the technical personnel in the field, and to make the above-mentioned features, purposes and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the embodiments. The embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0034] Example 1

[0035] A method for preparing a reinforced flame-retardant recycled polyester fiber comprises the following steps:

[0036] Step S1, preparation of flame retardant polymer: bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst, and high boiling point solvent were mixed evenly and added to a high pressure reactor, and the air in the reactor was replaced by an inert gas, followed by stirring and reacting at 130°C under normal pressure for 2 hours, then reducing the pressure to 10Pa, raising the temperature to 245°C, and stirring and reacting for 15 hours while maintaining the temperature and pressure. After the reaction was completed, the mixture was cooled to room temperature, precipitated in water, and the precipitated polymer was washed with ethanol for 3 times, and finally placed in a vacuum dryer at 85°C. The flame retardant polymer is dried to constant weight to obtain the flame retardant polymer; the molar ratio of the bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazole-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst and high boiling point solvent is 0.7:1:0.3:0.8:6; the catalyst is a mixture of ethylene glycol antimony, tetrabutyl titanate and p-toluenesulfonic acid in a mass ratio of 1:0.8:0.8; the high boiling point solvent is dimethyl sulfoxide; the inert gas is nitrogen; through GPC test, the number average molecular weight of the flame retardant polymer is 16170 g / mol, M W / M n =1.371; through elemental analysis and weight change calculation, the molar ratio of the structural units introduced by bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, and N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, respectively, is the same as the theoretical value.

[0037] Step S2, preparation of flame retardant masterbatch: the flame retardant polymer, coupling agent and inorganic filler prepared in step S1 are mixed evenly, added into a twin-screw extruder for melt blending and extrusion, and pelletized to obtain flame retardant masterbatch;

[0038] Step S3, spinning: the flame retardant masterbatch prepared in step S2, the recycled polyester, the antioxidant, and the lubricant are uniformly mixed to obtain a spinning raw material, which is then added to a composite spinning machine for spinning after drying, and then subjected to a drafting process to obtain a primary recycled polyester fiber;

[0039] Step S4, surface modification: (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt are uniformly dispersed in an organic solvent to form a dispersion, which is uniformly sprayed on the surface of the regenerated polyester fiber, and then heated under a nitrogen atmosphere by using 60 The fiber is radiated by a Co-γ-ray source, and then washed and dried to obtain the reinforced flame-retardant recycled polyester fiber.

[0040] The mass ratio of the flame retardant polymer, the coupling agent and the inorganic filler is 100:3:10; the coupling agent is the silane coupling agent KH550; the inorganic filler is a mixture of nano-boron fiber and light calcium carbonate in a mass ratio of 1:2; the average diameter of the nano-boron fiber is 30nm and the length is 3 microns; the particle size of the light calcium carbonate is 1000 mesh; the temperature of the melt blending extrusion in step S2 is 240°C and the extrusion pressure is 5MPa.

[0041] The mass ratio of the flame retardant masterbatch, recycled polyester, antioxidant and lubricant in step S3 is 8:1:0.8:0.5; the recycled polyester in step S3 is made from recycled polyester bottle flakes that are sorted, crushed, cleaned and dried in sequence; the antioxidant is antioxidant 1010; and the lubricant is pentaerythritol stearate.

[0042] The spinning temperature of the spinning is 250°C, and the spinning winding speed is 800m / min; the drawing processing parameters are a drawing multiple of 1.5 times, a hot plate temperature of 65°C, and a hot plate temperature of 115°C; the mass ratio of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, organic solvent, and regenerated polyester fiber in step S4 is 1:0.8:6:80; the organic solvent is toluene; the radiation grafting is carried out at room temperature, the absorbed dose is 10kGy, and the dose rate is 10kGy / h.

[0043] A reinforced flame-retardant regenerated polyester fiber prepared by adopting the method for preparing the reinforced flame-retardant regenerated polyester fiber.

[0044] Example 2

[0045] A method for preparing a reinforced flame-retardant recycled polyester fiber comprises the following steps:

[0046] Step S1, preparation of flame-retardant polymer: bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, a catalyst and a high boiling point solvent are mixed evenly and added into a high-pressure reactor, and the air in the reactor is replaced by an inert gas, followed by stirring and reacting at 133° C. under normal pressure for 2.5 hours, then reducing the pressure to 30 Pa, raising the temperature to 255° C., and stirring and reacting for 17 hours while maintaining the temperature and pressure. After the reaction is completed, the mixture is cooled to room temperature, precipitated in water, and the precipitated polymer is washed with ethanol 4 times, and finally dried in a vacuum dryer at 87° C. to constant weight to obtain a flame-retardant polymer;

[0047] Step S2, preparation of flame retardant masterbatch: the flame retardant polymer, coupling agent and inorganic filler prepared in step S1 are mixed evenly, added into a twin-screw extruder for melt blending and extrusion, and pelletized to obtain flame retardant masterbatch;

[0048] Step S3, spinning: the flame retardant masterbatch prepared in step S2, the recycled polyester, the antioxidant, and the lubricant are uniformly mixed to obtain a spinning raw material, which is then added to a composite spinning machine for spinning after drying, and then subjected to a drafting process to obtain a primary recycled polyester fiber;

[0049] Step S4, surface modification: (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt are uniformly dispersed in an organic solvent to form a dispersion, which is uniformly sprayed on the surface of the regenerated polyester fiber, and then heated under a nitrogen atmosphere by using 60 The fiber is radiated by a Co-γ-ray source, and then washed and dried to obtain the reinforced flame-retardant recycled polyester fiber.

[0050] The molar ratio of bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst and high boiling point solvent in step S1 is 0.7:1:0.3:0.9:7; the catalyst is a mixture of antimony ethylene glycol, tetrabutyl titanate and p-toluenesulfonic acid in a mass ratio of 1.3:0.8:0.9; the high boiling point solvent is dimethyl sulfoxide; and the inert gas is helium.

[0051] The mass ratio of the flame retardant polymer, the coupling agent and the inorganic filler is 100:3.5:13; the coupling agent is the silane coupling agent KH560; the inorganic filler is a mixture of nano-boron fiber and light calcium carbonate in a mass ratio of 1:1.7; the average diameter of the nano-boron fiber is 50nm and the length is 4 microns; the particle size of the light calcium carbonate is 1200 mesh; the temperature of the melt blending extrusion in step S2 is 245°C and the extrusion pressure is 6MPa.

[0052] The mass ratio of the flame retardant masterbatch, recycled polyester, antioxidant and lubricant in step S3 is 7:1:0.95:0.5; the recycled polyester is made from recycled polyester bottle flakes that are sorted, crushed, cleaned and dried in sequence; the antioxidant is antioxidant 168; the lubricant is ethylene bisstearamide; the spinning temperature of the spinning is 260°C, and the spinning winding speed is 1200m / min; the drawing processing parameters are a drawing multiple of 2 times, a hot plate temperature of 75°C, and a hot plate temperature of 135°C.

[0053] The mass ratio of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, organic solvent, and regenerated polyester fiber in step S4 is 1:0.9:7:80; the organic solvent is toluene; the radiation grafting is carried out at room temperature, the absorbed dose is 25 kGy, and the dose rate is 12 kGy / h.

[0054] A reinforced flame-retardant regenerated polyester fiber prepared by adopting the method for preparing the reinforced flame-retardant regenerated polyester fiber.

[0055] Example 3

[0056] A method for preparing a reinforced flame-retardant recycled polyester fiber comprises the following steps:

[0057] Step S1, preparation of flame-retardant polymer: bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, a catalyst and a high boiling point solvent are mixed uniformly and added into a high pressure reactor, the air in the reactor is replaced by an inert gas, and then stirred and reacted at 135° C. under normal pressure for 3 hours, and then the pressure is reduced to 60 Pa, the temperature is increased to 260° C., and the temperature is maintained and stirred for 19 hours. After the reaction is completed, the reaction is cooled to room temperature, precipitated in water, and the precipitated polymer is washed with ethanol for 5 times, and finally placed in a vacuum dryer and dried at 90° C. to constant weight to obtain a flame-retardant polymer;

[0058] Step S2, preparation of flame retardant masterbatch: the flame retardant polymer, coupling agent and inorganic filler prepared in step S1 are mixed evenly, added into a twin-screw extruder for melt blending and extrusion, and pelletized to obtain flame retardant masterbatch;

[0059] Step S3, spinning: the flame retardant masterbatch prepared in step S2, the recycled polyester, the antioxidant, and the lubricant are uniformly mixed to obtain a spinning raw material, which is then added to a composite spinning machine for spinning after drying, and then subjected to a drafting process to obtain a primary recycled polyester fiber;

[0060] Step S4, surface modification: (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt are uniformly dispersed in an organic solvent to form a dispersion, which is uniformly sprayed on the surface of the regenerated polyester fiber, and then heated under a nitrogen atmosphere by using 60 The fiber is radiated by a Co-γ-ray source, and then washed and dried to obtain the reinforced flame-retardant recycled polyester fiber.

[0061] The molar ratio of bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst, and high boiling point solvent in step S1 is 0.7:1:0.3:1:8; the catalyst is a mixture of antimony ethylene glycol, tetrabutyl titanate, and p-toluenesulfonic acid in a mass ratio of 1.5:0.8:1. The high boiling point solvent is dimethyl sulfoxide; the inert gas is neon; the mass ratio of the flame retardant polymer, the coupling agent and the inorganic filler is 100:4:15; the coupling agent is the silane coupling agent KH570; the inorganic filler is a mixture of nano boron fiber and light calcium carbonate in a mass ratio of 1:1.5; the average diameter of the nano boron fiber is 60nm and the length is 4.5 microns; the particle size of the light calcium carbonate is 1300 mesh.

[0062] The temperature of the melt blending extrusion in step S2 is 250° C., and the extrusion pressure is 7 MPa; the mass ratio of the flame retardant masterbatch, recycled polyester, antioxidant, and lubricant in step S3 is 6:1:0.9:0.5; the recycled polyester in step S3 is made from recycled polyester bottle flakes that are sorted, crushed, cleaned, and dried in sequence; the antioxidant is antioxidant 1076; and the lubricant is pentaerythritol stearate.

[0063] The spinning temperature of the spinning is 270°C, and the spinning winding speed is 1900m / min; the drawing processing parameters are a drawing multiple of 3 times, a hot plate temperature of 80°C, and a hot plate temperature of 175°C; the mass ratio of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, organic solvent, and regenerated polyester fiber in step S4 is 1:1:(6-10):80; the organic solvent is toluene; the radiation grafting is carried out at room temperature, the absorbed dose is 30kGy, and the dose rate is 15kGy / h.

[0064] A reinforced flame-retardant regenerated polyester fiber prepared by adopting the method for preparing the reinforced flame-retardant regenerated polyester fiber.

[0065] Example 4

[0066] A method for preparing a reinforced flame-retardant recycled polyester fiber comprises the following steps:

[0067] Step S1, preparation of flame-retardant polymer: bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, a catalyst and a high boiling point solvent are mixed uniformly and added into a high-pressure reactor, and the air in the reactor is replaced by an inert gas, followed by stirring and reacting at 138° C. under normal pressure for 3.5 hours, then reducing the pressure to 90 Pa, raising the temperature to 270° C., and stirring and reacting for 20 hours while maintaining the temperature and pressure. After the reaction is completed, the mixture is cooled to room temperature, precipitated in water, and the precipitated polymer is washed with ethanol for 5 times, and finally dried in a vacuum dryer at 93° C. to constant weight to obtain a flame-retardant polymer;

[0068] Step S2, preparation of flame retardant masterbatch: the flame retardant polymer, coupling agent and inorganic filler prepared in step S1 are mixed evenly, added into a twin-screw extruder for melt blending and extrusion, and pelletized to obtain flame retardant masterbatch;

[0069] Step S3, spinning: the flame retardant masterbatch prepared in step S2, the recycled polyester, the antioxidant, and the lubricant are uniformly mixed to obtain a spinning raw material, which is then added to a composite spinning machine for spinning after drying, and then subjected to a drafting process to obtain a primary recycled polyester fiber;

[0070] Step S4, surface modification: (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt are uniformly dispersed in an organic solvent to form a dispersion, which is uniformly sprayed on the surface of the regenerated polyester fiber, and then heated under a nitrogen atmosphere by using 60 The fiber is radiated by a Co-γ-ray source, and then washed and dried to obtain the reinforced flame-retardant recycled polyester fiber.

[0071] The molar ratio of bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst and high boiling point solvent in step S1 is 0.7:1:0.3:1.1:9.5; the catalyst is a mixture of antimony ethylene glycol, tetrabutyl titanate and p-toluenesulfonic acid in a mass ratio of 1.8:0.8:1.1; the high boiling point solvent is dimethyl sulfoxide; and the inert gas is argon.

[0072] The mass ratio of the flame retardant polymer, the coupling agent and the inorganic filler is 100:4.5:18; the coupling agent is a mixture of silane coupling agent KH550, silane coupling agent KH560 and silane coupling agent KH570 in a mass ratio of 1:2:3; the inorganic filler is a mixture of nano-boron fiber and light calcium carbonate in a mass ratio of 1:1.3; the average diameter of the nano-boron fiber is 80nm and the length is 5.5 microns; the particle size of the light calcium carbonate is 1400 mesh.

[0073] The temperature of the melt blending extrusion in step S2 is 255° C., and the extrusion pressure is 9 MPa; the mass ratio of the flame retardant masterbatch, the recycled polyester, the antioxidant, and the lubricant in step S3 is 5:1:0.95:0.5; the recycled polyester in step S3 is made by sorting, crushing, cleaning, and drying recycled polyester bottle flakes; the antioxidant is a mixture of antioxidant 1010, antioxidant 168, and antioxidant 1076 in a mass ratio of 1:1:2; the lubricant is a mixture of pentaerythritol stearate and ethylene bisstearamide in an ester ratio of 3:5; the spinning temperature of the spinning is 285° C., and the spinning winding speed is 2300 m / min; the drafting processing parameters are a drafting multiple of 3.5 times, a hot plate temperature of 90° C., and a hot plate temperature of 200° C.

[0074] The mass ratio of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, organic solvent, and regenerated polyester fiber in step S4 is 1:1.1:9:80; the organic solvent is toluene; the radiation grafting is carried out at room temperature, the absorbed dose is 40 kGy, and the dose rate is 20 kGy / h.

[0075] A reinforced flame-retardant regenerated polyester fiber prepared by adopting the method for preparing the reinforced flame-retardant regenerated polyester fiber.

[0076] Example 5

[0077] A method for preparing a reinforced flame-retardant recycled polyester fiber comprises the following steps:

[0078] Step S1, preparation of flame-retardant polymer: bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, a catalyst and a high boiling point solvent are mixed uniformly and added into a high-pressure reactor, and the air in the reactor is replaced by an inert gas, followed by stirring and reacting at 140° C. under normal pressure for 4 hours, then reducing the pressure to 100 Pa, raising the temperature to 275° C., and stirring and reacting for 22 hours while maintaining the temperature and pressure. After the reaction is completed, the mixture is cooled to room temperature, precipitated in water, and the precipitated polymer is washed with ethanol for 6 times, and finally dried in a vacuum dryer at 95° C. to constant weight to obtain a flame-retardant polymer;

[0079] Step S2, preparation of flame retardant masterbatch: the flame retardant polymer, coupling agent and inorganic filler prepared in step S1 are mixed evenly, added into a twin-screw extruder for melt blending and extrusion, and pelletized to obtain flame retardant masterbatch;

[0080] Step S3, spinning: the flame retardant masterbatch prepared in step S2, the recycled polyester, the antioxidant, and the lubricant are uniformly mixed to obtain a spinning raw material, which is then added to a composite spinning machine for spinning after drying, and then subjected to a drafting process to obtain a primary recycled polyester fiber;

[0081] Step S4, surface modification: (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt are uniformly dispersed in an organic solvent to form a dispersion, which is uniformly sprayed on the surface of the regenerated polyester fiber, and then heated under a nitrogen atmosphere by using 60 The fiber is radiated by a Co-γ-ray source, and then washed and dried to obtain the reinforced flame-retardant recycled polyester fiber.

[0082] The molar ratio of bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst and high boiling point solvent in step S1 is 0.7:1:0.3:1.2:10; the catalyst is a mixture of antimony ethylene glycol, tetrabutyl titanate and p-toluenesulfonic acid in a mass ratio of 2:0.8:1.2; the high boiling point solvent is dimethyl sulfoxide; and the inert gas is nitrogen.

[0083] The mass ratio of the flame retardant polymer, the coupling agent and the inorganic filler is 100:5:20; the coupling agent is the silane coupling agent KH550; the inorganic filler is a mixture of nano-boron fiber and light calcium carbonate in a mass ratio of 1:1; the average diameter of the nano-boron fiber is 90nm and the length is 6 microns; the particle size of the light calcium carbonate is 1500 mesh; the temperature of the melt blending extrusion in step S2 is 260°C and the extrusion pressure is 10MPa; the mass ratio of the flame retardant masterbatch, recycled polyester, antioxidant and lubricant in step S3 is 4:1:1:0.5; the recycled polyester in step S3 is made by sorting, crushing, washing and drying recycled polyester bottle flakes; the antioxidant is an antioxidant 1010; the lubricant is ethylene bisstearamide; the spinning temperature of the spinning is 290°C, and the spinning winding speed is 2400m / min; the drawing processing parameters are a drawing multiple of 4 times, a hot plate temperature of 95°C, and a hot plate temperature of 205°C; the mass ratio of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, organic solvent, and regenerated polyester fiber in step S4 is 1:1.2:10:80; the organic solvent is toluene; the radiation grafting is carried out at room temperature, the absorbed dose is 45kGy, and the dose rate is 20kGy / h.

[0084] A reinforced flame-retardant regenerated polyester fiber prepared by adopting the method for preparing the reinforced flame-retardant regenerated polyester fiber.

[0085] Comparative Example 1

[0086] A reinforced flame-retardant regenerated polyester fiber and a preparation method thereof, which are basically the same as those in Example 1, except that an equal amount of bis(4-carboxyphenyl)phenylphosphine oxide is used instead of N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid; and an equal amount of (perfluoropropane-2,2-diyl)bis(4,1-phenylene)diacrylate is used instead of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt.

[0087] Comparative Example 2

[0088] A reinforced flame-retardant regenerated polyester fiber and a preparation method thereof, which are basically the same as those in Example 1, except that an equal amount of N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid is used to replace bis(4-carboxyphenyl)phenylphosphine oxide; and an equal amount of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt is used to replace (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate.

[0089] The performance of the enhanced flame-retardant recycled polyester fiber samples described in Examples 1-5 and Comparative Examples 1-2 was tested. The test results are shown in Table 1. The test method is as follows:

[0090] (1) Limiting oxygen index: Refer to GB / T5454-1997 "Textile combustion performance test oxygen index method" to test the limiting oxygen index of each product;

[0091] (2) Breaking strength: The mechanical properties were tested with reference to GB / T 14344-2022 “Test method for tensile properties of chemical filaments”. The specific test conditions were as follows: the pre-tension value was set to 5 cN, the clamping distance was set to 250 mm, the tensile speed was set to 250 mm / min, and each group of fiber samples was tested 20 times.

[0092] (3) Heat aging resistance: After each product is placed at 90°C for 120 hours, it is cooled to room temperature and the breaking strength is tested again according to the breaking strength test method (2). The retention rate of the breaking strength after aging is calculated. The larger the value, the better the aging resistance.

[0093] Table 1

[0094]

[0095] It can be seen from Table 1 that the reinforced flame-retardant regenerated polyester fiber disclosed in the embodiment of the present invention has better flame retardancy, mechanical properties and heat aging resistance than the comparative example; the combined use of N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, bis(4-carboxyphenyl)phenylphosphine oxide, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt and (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate is beneficial to improving the above properties.

[0096] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a reinforced flame-retardant recycled polyester fiber, characterized in that: The steps include: Step S1, preparation of flame-retardant polymer: bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, a catalyst and a high boiling point solvent are mixed uniformly and added into a high-pressure reactor, and the air in the reactor is replaced by an inert gas, followed by stirring and reacting at 130-140° C. under normal pressure for 2-4 hours, then reducing the pressure to 10-100 Pa, raising the temperature to 245-275° C., stirring and reacting for 15-22 hours while maintaining the temperature and pressure, cooling to room temperature after the reaction is completed, precipitating in water, washing the precipitated polymer with ethanol for 3-6 times, and finally drying in a vacuum dryer at 85-95° C. to constant weight to obtain a flame-retardant polymer; Step S2, preparation of flame retardant masterbatch: the flame retardant polymer, coupling agent and inorganic filler prepared in step S1 are mixed evenly, added into a twin-screw extruder for melt blending and extrusion, and pelletized to obtain flame retardant masterbatch; Step S3, spinning: the flame retardant masterbatch prepared in step S2, the recycled polyester, the antioxidant, and the lubricant are uniformly mixed to obtain a spinning raw material, which is then added to a composite spinning machine for spinning after drying, and then subjected to a drafting process to obtain a primary recycled polyester fiber; Step S4, surface modification: (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt are uniformly dispersed in an organic solvent to form a dispersion, which is uniformly sprayed on the surface of the regenerated polyester fiber, and then heated under a nitrogen atmosphere by using 60 The fiber is radiated by a Co-γ-ray source, and then washed and dried to obtain the reinforced flame-retardant recycled polyester fiber.

2. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The molar ratio of bis(4-carboxyphenyl)phenylphosphine oxide, 4,8-tricyclo[5.2.1.O2,7]decanedimethanol, N-(4H-1,2,4-triazol-4-yl)diphenylamine-4,4'-dicarboxylic acid, catalyst and high boiling point solvent in step S1 is 0.7:1:0.3:(0.8-1.2):(6-10).

3. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The catalyst is a mixture of antimony ethylene glycol, tetrabutyl titanate and p-toluenesulfonic acid in a mass ratio of (1-2):0.8:(0.8-1.2); the high boiling point solvent is dimethyl sulfoxide; and the inert gas is any one of nitrogen, helium, neon and argon.

4. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The mass ratio of the flame retardant polymer, the coupling agent and the inorganic filler is 100:(3-5):(10-20); the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560 and silane coupling agent KH570; the inorganic filler is a mixture of nano boron fiber and light calcium carbonate in a mass ratio of 1:(1-2); the average diameter of the nano boron fiber is 30-90nm and the length is 3-6 microns; the particle size of the light calcium carbonate is 1000-1500 mesh.

5. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The temperature of the melt blending extrusion in step S2 is 240-260° C., and the extrusion pressure is 5-10 MPa.

6. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The mass ratio of the flame retardant masterbatch, recycled polyester, antioxidant and lubricant in step S3 is (4-8):1:(0.8-1):0.5; the recycled polyester is made from recycled polyester bottle flakes that are sorted, crushed, cleaned and dried in sequence; the antioxidant is at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076; the lubricant is at least one of pentaerythritol stearate and ethylene bisstearamide.

7. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The spinning temperature of the spinning is 250-290°C, and the spinning winding speed is 800-2400m / min; the drawing processing parameters are a drawing multiple of 1.5-4 times, a hot plate temperature of 65-95°C, and a hot plate temperature of 115-205°C.

8. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The mass ratio of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, organic solvent, and regenerated polyester fiber in step S4 is 1:(0.8-1.2):(6-10):80; the organic solvent is toluene.

9. The method for preparing the reinforced flame-retardant recycled polyester fiber according to claim 1, characterized in that: The radiation grafting is carried out at room temperature, the absorbed dose is 10-45 kGy, and the dose rate is 10-20 kGy / h.

10. A reinforced flame-retardant regenerated polyester fiber prepared by the method for preparing the reinforced flame-retardant regenerated polyester fiber according to any one of claims 1 to 9.

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