CN111574700A

CN111574700A - Phosphorus and fluorine-containing flame-retardant polyester fiber and preparation method thereof

Info

Publication number: CN111574700A
Application number: CN202010546687.4A
Authority: CN
Inventors: 徐松波
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2020-08-25

Abstract

The invention discloses a phosphorus and fluorine containing flame retardant polyester fiber and a preparation method thereof, wherein the preparation method comprises the following steps: reacting hexafluoropropylene oxide with a flame retardant ODOPB to prepare a phosphorus-fluorine-containing monomer, carrying out ester exchange and polycondensation with ethylene terephthalate to prepare copolyester, and carrying out melt spinning to obtain polyester fiber; the phosphorus element can catalyze the system to form a phosphorus-rich carbon layer, so that the phosphorus-rich carbon layer plays a role of a protective layer to prevent organic matters from being further decomposed, and the introduction of the fluorine element can improve the thermal stability of the polyester, thereby improving the flame retardant property of the system and realizing the synergistic effect of the phosphorus-fluorine flame retardant elements. Meanwhile, fluorine atoms have lower surface energy, can improve the antifouling property of the fiber surface, and has potential application prospect in preparing antifouling flame-retardant textiles.

Description

Phosphorus and fluorine-containing flame-retardant polyester fiber and preparation method thereof

Technical Field

The invention belongs to the field of synthetic fibers, and particularly relates to a phosphorus and fluorine-containing flame-retardant polyester fiber and a preparation method thereof.

Background

The flame-retardant polyester fiber has wide market prospect in clothing, ornaments and industrial products, such as children clothing, special industry clothing, textile ornaments used in public places such as hotels and entertainment, textiles for transportation, textiles for packaging and the like. The flame retardants commonly used are classified into halogen-based, nitrogen-based, organic phosphorus-based, inorganic phosphorus-based, boron-based, silicon-based, molybdenum-based, and the like, depending on the kind of the flame retardant element. Different flame retardants follow different flame retardant mechanisms, halogen-containing flame retardants can be decomposed at high temperature to generate hydrogen halide gas, and high-energy HO & free radical generated in the combustion process can be captured and converted into low-energy X & water, so that the effect of inhibiting combustion is achieved; the phosphorus flame retardant can generate carbon black film to be attached to the surface of an organic matter in combustion to isolate oxygen so as to achieve the flame retardant effect.

In recent years, composite flame retardants such as phosphorus-nitrogen flame retardants and phosphorus-silicon-fluorine flame retardants have been the focus of research. CN 104387571B discloses a phosphorus-nitrogen-containing flame-retardant copolyester, which realizes in-situ synergistic flame retardance of phosphorus-nitrogen flame-retardant elements by introducing nitrogen-containing tri (2-hydroxyethyl) isocyanuric acid, phosphorus-containing 2-carboxyethyl phenyl phosphinic acid and phosphate dihydric alcohol in the polycondensation process, and can be applied to flame-retardant textiles. CN 102634174B discloses a silicon-phosphorus-fluorine flame-retardant copolyester film, which has synergistic flame-retardant effect of phosphorus, silicon and fluorine elements, effectively improves char yield, and has flame-retardant performance reaching VTM-0 level.

As the molecular chain of the fiber-grade polyester must have higher regularity and the cellosilk with excellent mechanical property can be obtained through stretching orientation, the modification difficulty of the polyester fiber in the synthesis stage is higher, and the report on obtaining the phosphorus-fluorine-containing flame-retardant polyester fiber by modifying the polyester in the synthesis stage is not found.

Disclosure of Invention

The invention aims to provide a phosphorus and fluorine-containing flame-retardant polyester fiber and a preparation method thereof. The phosphorus element can catalyze the system to form a phosphorus-rich carbon layer, so that the phosphorus-rich carbon layer plays a role of a protective layer to prevent organic matters from being further decomposed, and the introduction of the fluorine element can improve the thermal stability of the polyester, thereby improving the flame retardant property of the system and realizing the synergistic effect of the phosphorus-fluorine flame retardant elements. Meanwhile, fluorine atoms have lower surface energy, so that the antifouling property of the fiber surface can be improved, and the fiber has a potential application prospect in preparation of antifouling flame-retardant textiles.

The invention also aims to provide a preparation method of the phosphorus-fluorine-containing flame-retardant polyester fiber.

The above purpose of the invention is realized by the following technical scheme:

the phosphorus and fluorine containing flame retardant polyester fiber has the following structural formula:

wherein m is 8-30, and n is 15-85.

The reaction process and the preparation method of the phosphorus-fluorine-containing flame-retardant polyester fiber are as follows:

1. preparation of phosphorus-fluorine-containing monomer (M1)

Putting a flame retardant ODOPB and hexafluoropropylene oxide into a reaction kettle according to a certain proportion, adding water, fully stirring and dissolving, adjusting the pH to 8-10 by using NaOH, reacting for 4 hours at 70-90 ℃, and passing through a column to volatilize a solvent to obtain yellow oily liquid, namely the phosphorus-fluorine-containing monomer (M1).

The feeding molar ratio of the flame retardant ODOPB, the hexafluoropropylene oxide and the water is 1: 1.3-1.5: 50-60.

The structural formula of the flame retardant ODOPB is as follows:

the phosphorus-fluorine-containing monomer (M1) has the following structural formula:

2. preparation of ethylene terephthalate

Adding dimethyl terephthalate (DMT), Ethylene Glycol (EG) and manganese acetate serving as a catalyst into a round-bottom flask, and introducing N₂And carrying out ester exchange reaction at 240-260 ℃. When the volume of the condensed and recovered methanol is not less than 90% of the theoretical volume, the transesterification reaction is finished, and ethylene terephthalate is prepared.

The feeding molar ratio of DMT to EG is 1:2, and the feeding amount of manganese acetate is 0.05 percent of the mass of DMT.

The structural formula of the ethylene terephthalate is as follows:

3. preparation of copolyesters

Putting the ethylene terephthalate, M1, trimethyl phosphate and antimony acetate into a reaction kettle according to a certain proportion, and introducingN₂Performing ester exchange reaction at 240-260 ℃ for 1-2 h, vacuumizing, and performing pre-polycondensation for 1-3 h under the pressure of 800-1000 Pa; and continuously heating to 260-290 ℃, controlling the vacuum degree to be lower than 50Pa, starting final polycondensation for 4-7 h, relieving the vacuum with nitrogen, discharging, cooling and slicing to obtain the copolyester (I).

The feeding molar ratio of the ethylene glycol terephthalate to the M1 is 1-5: 1, the dosage of the antimony acetate is 0.03-0.1% of the weight of the ethylene glycol terephthalate, and the dosage of the trimethyl phosphate is 0.03-0.1% of the weight of the ethylene glycol terephthalate.

4. Preparation of phosphorus-fluorine-containing flame-retardant polyester fiber by melt spinning

Feeding copolyester slices into a screw extruder, extruding after melting, filtering impurities through a prefilter, metering by a metering pump and a filter layer of a spinning assembly in sequence, finally spraying out from fine holes of a spinneret plate, forming silk strips through air blowing and cooling, oiling, winding on a sleeve through a godet roller and finally a high-speed winding device to obtain the POY fiber.

The technological parameters in the spinning process are as follows: the spinning temperature is 260-290 ℃, the POY spinning speed is 3000-4000 m/min, the side blowing temperature is 26-28 ℃, the relative humidity of air supply is 70-80%, and the air speed is 0.4-0.5 m/s.

The invention has the following advantages and beneficial effects:

(1) the phosphorus and fluorine are used for flame retardance, the phosphorus can catalyze the system to form a phosphorus-rich carbon layer, the phosphorus-rich carbon layer plays a role of a protective layer to prevent organic matters from being further decomposed, and the introduction of the fluorine can improve the thermal stability of polyester, so that the flame retardance of the system is improved, and the synergistic effect of the phosphorus and fluorine flame retardant elements is realized.

(2) The invention introduces fluorine atoms which have the highest electronegativity (4.0), smaller van der Waals radius (0.135nm), low polarization degree and weaker intermolecular binding energy, thereby being beneficial to reducing the surface energy, solvent resistance and chemical resistance of fibers and obtaining antifouling polyester textiles.

(3) According to the invention, the functional third monomer is introduced to participate in the polycondensation of terephthalic acid and ethylene glycol, so that the problems of performance timeliness, durability and the like are fundamentally solved. The preparation process is simple, the viscosity in the polycondensation process is controllable, the product has stable performance and good fiber forming property, and has wide application prospect in preparing antifouling and flame-retardant textiles.

Drawings

FIG. 1 is a schematic representation of example 1 of a phosphorus and fluorine-containing monomer (M1) and a copolyester¹H-NMR spectrum.

Detailed Description

The present invention will be described in further detail with reference to specific examples, which are not intended to limit the present invention in any manner. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

The test of the invention comprises the following steps:

intrinsic viscosity: the intrinsic viscosity of the copolyester is measured by adopting a phenol and tetrachloroethane solution with the mass ratio of 1:1 and a full-automatic viscosity measuring instrument, wherein the diameter of a capillary is 1.2 mm.

Limiting Oxygen Index (LOI): the test was carried out according to the national standard GB/T2406-1993.

Differential Scanning Calorimetry (DSC): in the nitrogen atmosphere, the nitrogen flow rate is 20mL/min, the temperature is increased from room temperature to 300 ℃, and then the temperature is reduced to 0 ℃ so as to eliminate the heat history; the temperature is raised for the second time from 0 ℃ to 300 ℃, and the heating rate is 20 ℃/min; the cold crystallization temperature Tc, melting temperature Tm, and peak enthalpy of crystallization Δ H for each example are shown in Table 1.

Thermogravimetric analysis (TG): the amount of the sample is 6-8 mg, the nitrogen atmosphere is adopted, the nitrogen flow rate is 100mL/min, the heating rate is 10 ℃/min, the scanning temperature is 30-500 ℃, and the residual ash rate of each example at 500 ℃ is shown in Table 1.

Fiber tensile test: the monofilament strength tester is adopted to test the strength, the elongation and the like of the monofilament of the phosphorus-fluorine-containing flame-retardant polyester fiber according to the tensile property test method of the synthetic fiber filament of the national standard (GB/T14344-2003).

Example 1

(1) Preparation of phosphorus-fluorine-containing monomer (M1)

Weighing fire retardants ODOPB, hexafluoropropylene oxide and deionized water according to a molar ratio of 1:1.4:50, putting the materials into a reaction kettle, fully stirring and dissolving, adding NaOH solid, adjusting the pH to 8, reacting at 80 ℃ for 4 hours, taking dichloromethane as an eluent, and separating a column by silica gel column chromatography and volatilizing the solvent to obtain a tawny oily liquid, namely a fluorine-containing dihydric alcohol monomer, which is marked as M1.

(2) Preparation of ethylene terephthalate

Dimethyl terephthalate (DMT) and Ethylene Glycol (EG) are weighed according to the molar charge ratio of 1:2 and added into a round-bottom flask, 0.05 weight percent of manganese acetate in DMT is added, and N is introduced₂The transesterification reaction was carried out at 240 ℃. When the volume of the methanol recovered by condensation is not less than 90% of the theoretical volume, the transesterification reaction is ended to obtain ethylene terephthalate.

(3) Preparation of copolyesters

The feeding molar ratio of the ethylene terephthalate to the M1 is 1:1, the dosage of the antimony acetate is 0.05 percent of the weight of the ethylene terephthalate, and the dosage of the trimethyl phosphate is 0.05 percent of the weight of the ethylene terephthalate. The ester exchange reaction temperature is 260 ℃, and the reaction time is 2 hours; the temperature of the pre-polycondensation is 260 ℃, the vacuum degree is controlled to be 1000Pa, and the reaction time is 2.5 h; the temperature of final polycondensation is 280 ℃, the vacuum degree is lower than 50Pa, and the reaction time is 5.5 h.

The spinning extrusion temperature is 260 ℃, the cooling air temperature is 28 ℃, the air speed is 0.4m/s, the air supply relative humidity is 80%, and the spinning speed is 3800 m/min.

Referring to FIG. 1, of phosphorus-fluorine containing monomer (M1) and copolyester¹The H-NMR spectrum is shown in FIG. 1.

Example 2

M1 was prepared in the same manner as in example 1.

The feeding molar ratio of the ethylene terephthalate to the M1 is 2:1, the dosage of the antimony acetate is 0.05 percent of the weight of the ethylene terephthalate, and the dosage of the trimethyl phosphate is 0.05 percent of the weight of the ethylene terephthalate. The ester exchange reaction temperature is 255 ℃, and the reaction time is 2 hours; the temperature of the pre-polycondensation is 255 ℃, the vacuum degree is controlled to be 1000Pa, and the reaction time is 3 h; the temperature of final polycondensation is 280 ℃, the vacuum degree is lower than 50Pa, and the reaction time is 6 h.

The spinning extrusion temperature is 280 ℃, the cooling air temperature is 28 ℃, the air speed is 0.5m/s, the air supply relative humidity is 80 percent, and the spinning speed is 3800 m/min.

Example 3

M1 was prepared in the same manner as in example 1.

The feeding molar ratio of the ethylene terephthalate to the M1 is 3:1, the dosage of the antimony acetate is 0.05 percent of the weight of the ethylene terephthalate, and the dosage of the trimethyl phosphate is 0.05 percent of the weight of the ethylene terephthalate. The ester exchange reaction temperature is 250 ℃, and the reaction time is 2 hours; the temperature of the pre-polycondensation is 250 ℃, the vacuum degree is controlled to be 800Pa, and the reaction time is 1.5 h; the temperature of final polycondensation is 290 ℃, the vacuum degree is lower than 50Pa, and the reaction time is 5 h.

The spinning extrusion temperature is 270 ℃, the cooling air temperature is 28 ℃, the air speed is 0.5m/s, the air supply relative humidity is 70%, and the spinning speed is 4000 m/min.

Example 4

M1 was prepared in the same manner as in example 1.

The feeding molar ratio of the ethylene terephthalate to the M1 is 4:1, the dosage of the antimony acetate is 0.05 percent of the weight of the ethylene terephthalate, and the dosage of the trimethyl phosphate is 0.05 percent of the weight of the ethylene terephthalate. The ester exchange reaction temperature is 240 ℃, and the reaction time is 1.5 h; the temperature of the pre-polycondensation is 240 ℃, the vacuum degree is controlled to be 1000Pa, and the reaction time is 2 h; the temperature of final polycondensation is 270 ℃, the vacuum degree is lower than 50Pa, and the reaction time is 7 h.

The spinning extrusion temperature is 260 ℃, the cooling air temperature is 26 ℃, the air speed is 0.5m/s, the air supply relative humidity is 80%, and the spinning speed is 4000 m/min.

Example 5

M1 was prepared in the same manner as in example 1.

The feeding molar ratio of the ethylene terephthalate to the M1 is 5:1, the dosage of the antimony acetate is 0.05 percent of the weight of the ethylene terephthalate, and the dosage of the trimethyl phosphate is 0.05 percent of the weight of the ethylene terephthalate. The ester exchange reaction temperature is 250 ℃, and the reaction time is 1 h; the temperature of the pre-polycondensation is 250 ℃, the vacuum degree is controlled to be 1000Pa, and the reaction time is 2 h; the temperature of final polycondensation is 270 ℃, the vacuum degree is lower than 50Pa, and the reaction time is 4 h.

The spinning extrusion temperature is 270 ℃, the cooling air temperature is 26 ℃, the air speed is 0.4m/s, the air supply relative humidity is 70%, and the spinning speed is 4000 m/min.

Comparative example 1

Fiber grade polyester chips were purchased from southeast chemical fiber materials ltd, ceremony.

The polyester fibers of examples 1-5 and comparative example 1 and the corresponding tests are listed in table 1.

TABLE 1

As can be seen from the comparison of the examples and the comparative examples, the addition of the phosphorus and fluorine-containing third monomer enables the polyester fiber to have higher limiting oxygen index and residual ash rate and to show better flame retardance. As can be seen from the table, when the addition amount of M1 is more, the flame retardant property of the polyester fiber is better, but the crystallization temperature and the crystallinity of the polyester are also reduced, and the reduction of the crystallization temperature can cause the crystallization to be too fast to form a defective crystalline region, thereby affecting the mechanical properties of the fiber yarn, but within the addition amount range of M1, the phosphorus and fluorine-containing flame retardant polyester fiber still maintains relatively ideal tensile strength and elasticity, which indicates that the phosphorus and fluorine-containing flame retardant polyester fiber has good fiber forming property.

Claims

1. The phosphorus-fluorine-containing flame-retardant polyester fiber is characterized by having a structure shown in a formula (I):

wherein m is 8-30, and n is 15-85.

2. The phosphorus and fluorine containing flame retardant polyester fiber and the preparation method thereof are characterized by comprising the following steps:

(1) preparation of phosphorus-fluorine-containing monomer (M1)

Reacting a flame retardant ODOPB and hexafluoropropylene oxide at the temperature of 60-80 ℃ for 4 hours to obtain a phosphorus-fluorine-containing monomer (M1), wherein the structural formula is shown as the formula (II):

(2) preparation of ethylene terephthalate

Performing ester exchange reaction on dimethyl phthalate and ethylene glycol by using manganese acetate as a catalyst to prepare ethylene glycol terephthalate, wherein the structural formula is shown as the formula (III):

(3) preparation of copolyesters

Antimony acetate is used as a catalyst, trimethyl phosphate is used as a stabilizer, and a phosphorus-fluorine-containing monomer (M1) and ethylene terephthalate are subjected to ester exchange, pre-polycondensation and final polycondensation to prepare copolyester (I);

(4) preparation of phosphorus-fluorine-containing flame-retardant polyester fiber by melt spinning

Feeding the copolyester into a screw extruder, and preparing the phosphorus-fluorine-containing flame-retardant polyester fiber through metering, extruding, cooling, stretching and winding.

3. The phosphorus and fluorine containing flame retardant polyester fiber and the preparation method thereof according to claim 2, characterized in that:

the structural formula of the flame retardant ODOPB in the step (1) is shown as the formula (IV):

the feeding molar ratio of the flame retardant ODOPB in the step (1) to the hexafluoropropylene oxide is 1: 1.1-1.3;

the alkaline condition in the step (1) is NaOH aqueous solution with pH of 8-10;

the feeding molar ratio of the dimethyl phthalate to the ethylene glycol in the step (2) is 1:2, and the feeding amount of the manganese acetate is 0.05 percent of the mass of the dimethyl phthalate;

the feeding molar ratio of the ethylene terephthalate and the phosphorus-fluorine-containing monomer (M1) in the step (3) is 1-5: 1, the dosage of the antimony acetate is 0.03-0.1% of the weight of the ethylene terephthalate, and the dosage of the trimethyl phosphate is 0.03-0.1% of the weight of the ethylene terephthalate;

the transesterification reaction temperature of the step (3) is 240-260 ℃, and the reaction time is 1-2 h; the pre-polycondensation reaction temperature is 240-260 ℃, the reaction pressure is 800-1000 Pa, and the reaction time is 1-3 h; the final polycondensation reaction temperature is 260-290 ℃, the reaction pressure is lower than 50Pa, and the reaction time is 4-7 h;

the extrusion temperature in the step (4) is 260-290 ℃; the cooling air temperature is 26-28 ℃, the air speed is 0.4-0.5 m/s, and the relative humidity of the air supply is 70-80%; the spinning speed is 3000-4000 m/min.

4. The phosphorus and fluorine containing flame retardant polyester fiber and the preparation method thereof according to any one of claims 1 to 3, wherein the flame retardant polyester fiber comprises the following components: the intrinsic viscosity of the copolyester is 0.8-1.2 dL/g.