CN114574988A - Preparation method of flame-retardant polyamide 6 fiber based on phosphorus-nitrogen synergistic flame retardant - Google Patents
Preparation method of flame-retardant polyamide 6 fiber based on phosphorus-nitrogen synergistic flame retardant Download PDFInfo
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- CN114574988A CN114574988A CN202111671951.8A CN202111671951A CN114574988A CN 114574988 A CN114574988 A CN 114574988A CN 202111671951 A CN202111671951 A CN 202111671951A CN 114574988 A CN114574988 A CN 114574988A
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- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 title claims abstract description 138
- 239000003063 flame retardant Substances 0.000 title claims abstract description 138
- 229920002292 Nylon 6 Polymers 0.000 title claims abstract description 123
- 239000000835 fiber Substances 0.000 title claims abstract description 71
- YUWBVKYVJWNVLE-UHFFFAOYSA-N [N].[P] Chemical compound [N].[P] YUWBVKYVJWNVLE-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 230000002195 synergetic effect Effects 0.000 title claims abstract description 38
- 238000002360 preparation method Methods 0.000 title claims abstract description 31
- 238000002156 mixing Methods 0.000 claims abstract description 18
- 238000001816 cooling Methods 0.000 claims abstract description 17
- 238000004804 winding Methods 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 12
- 239000000203 mixture Substances 0.000 claims abstract description 7
- 238000001035 drying Methods 0.000 claims abstract description 4
- 238000001125 extrusion Methods 0.000 claims abstract description 3
- 238000009987 spinning Methods 0.000 claims description 63
- 239000004594 Masterbatch (MB) Substances 0.000 claims description 25
- DWSWCPPGLRSPIT-UHFFFAOYSA-N benzo[c][2,1]benzoxaphosphinin-6-ium 6-oxide Chemical compound C1=CC=C2[P+](=O)OC3=CC=CC=C3C2=C1 DWSWCPPGLRSPIT-UHFFFAOYSA-N 0.000 claims description 14
- 238000007664 blowing Methods 0.000 claims description 14
- HUMNYLRZRPPJDN-UHFFFAOYSA-N benzaldehyde Chemical compound O=CC1=CC=CC=C1 HUMNYLRZRPPJDN-UHFFFAOYSA-N 0.000 claims description 10
- 239000003960 organic solvent Substances 0.000 claims description 8
- 239000002262 Schiff base Substances 0.000 claims description 7
- 125000004093 cyano group Chemical group *C#N 0.000 claims description 7
- 150000004753 Schiff bases Chemical class 0.000 claims description 6
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 6
- HYZJCKYKOHLVJF-UHFFFAOYSA-N 1H-benzimidazole Chemical compound C1=CC=C2NC=NC2=C1 HYZJCKYKOHLVJF-UHFFFAOYSA-N 0.000 claims description 5
- QNGNSVIICDLXHT-UHFFFAOYSA-N para-ethylbenzaldehyde Natural products CCC1=CC=C(C=O)C=C1 QNGNSVIICDLXHT-UHFFFAOYSA-N 0.000 claims description 5
- 239000003054 catalyst Substances 0.000 claims description 4
- 238000002074 melt spinning Methods 0.000 claims description 4
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 claims description 4
- BSYJHYLAMMJNRC-UHFFFAOYSA-N 2,4,4-trimethylpentan-2-ol Chemical compound CC(C)(C)CC(C)(C)O BSYJHYLAMMJNRC-UHFFFAOYSA-N 0.000 claims description 2
- 238000007259 addition reaction Methods 0.000 claims description 2
- 238000006482 condensation reaction Methods 0.000 claims description 2
- 238000005453 pelletization Methods 0.000 claims description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims description 2
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims 1
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 48
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 21
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 21
- 239000000155 melt Substances 0.000 description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 21
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 20
- 239000000843 powder Substances 0.000 description 20
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 14
- 238000012360 testing method Methods 0.000 description 14
- 238000001291 vacuum drying Methods 0.000 description 14
- 238000010992 reflux Methods 0.000 description 13
- 238000002036 drum drying Methods 0.000 description 11
- 238000005507 spraying Methods 0.000 description 11
- 239000003795 chemical substances by application Substances 0.000 description 10
- 239000008367 deionised water Substances 0.000 description 10
- 229910021641 deionized water Inorganic materials 0.000 description 10
- 238000004896 high resolution mass spectrometry Methods 0.000 description 10
- 229910052757 nitrogen Inorganic materials 0.000 description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 8
- 238000002485 combustion reaction Methods 0.000 description 8
- WZWIQYMTQZCSKI-UHFFFAOYSA-N 4-cyanobenzaldehyde Chemical compound O=CC1=CC=C(C#N)C=C1 WZWIQYMTQZCSKI-UHFFFAOYSA-N 0.000 description 7
- JWYUFVNJZUSCSM-UHFFFAOYSA-N 2-aminobenzimidazole Chemical compound C1=CC=C2NC(N)=NC2=C1 JWYUFVNJZUSCSM-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- MZZZAWDOYQWKMR-UHFFFAOYSA-N 6-methyl-1h-benzimidazol-2-amine Chemical compound CC1=CC=C2N=C(N)NC2=C1 MZZZAWDOYQWKMR-UHFFFAOYSA-N 0.000 description 5
- -1 aromatic Schiff base Chemical class 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 229960000583 acetic acid Drugs 0.000 description 4
- 125000003277 amino group Chemical group 0.000 description 4
- 125000003785 benzimidazolyl group Chemical group N1=C(NC2=C1C=CC=C2)* 0.000 description 4
- 239000012362 glacial acetic acid Substances 0.000 description 4
- 206010020112 Hirsutism Diseases 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- FYSNRJHAOHDILO-UHFFFAOYSA-N thionyl chloride Chemical compound ClS(Cl)=O FYSNRJHAOHDILO-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 239000004114 Ammonium polyphosphate Chemical class 0.000 description 1
- 241001391944 Commicarpus scandens Species 0.000 description 1
- 235000019826 ammonium polyphosphate Nutrition 0.000 description 1
- 229920001276 ammonium polyphosphate Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical compound O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
Images
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
- D01F6/90—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyamides
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/08—Melt spinning methods
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/08—Melt spinning methods
- D01D5/088—Cooling filaments, threads or the like, leaving the spinnerettes
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/08—Melt spinning methods
- D01D5/096—Humidity control, or oiling, of filaments, threads or the like, leaving the spinnerettes
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F1/00—General methods for the manufacture of artificial filaments or the like
- D01F1/02—Addition of substances to the spinning solution or to the melt
- D01F1/07—Addition of substances to the spinning solution or to the melt for making fire- or flame-proof filaments
Abstract
The invention relates to a preparation method of a flame-retardant polyamide 6 fiber based on a phosphorus-nitrogen synergistic flame retardant. The method comprises the following steps: mixing the phosphorus-nitrogen synergistic flame retardant and polyamide 6 slices, feeding the mixture into a double-screw extruder, granulating to obtain flame-retardant polyamide 6 master batches, mixing the flame-retardant polyamide 6 master batches with the polyamide 6 slices, drying, performing melt extrusion, cooling, oiling, drafting and winding. The polyamide 6 fiber prepared by the method has excellent flame retardant property and mechanical property.
Description
Technical Field
The invention belongs to the field of preparation of polyamide 6 fibers, and particularly relates to a preparation method of a flame-retardant polyamide 6 fiber based on a phosphorus-nitrogen synergistic flame retardant.
Background
Polyamide 6 fiber is the synthetic fiber of the earliest industrialization in the world, has the outstanding advantages of high strength, light weight, wear resistance, comfortable wearing and the like, and is widely applied to various industries such as clothes, cables, silk screens and the like. However, polyamide 6 fibers are flammable, and when a fire breaks out, the formed droplets, flames and smog greatly increase casualties and property loss, so that the development of polyamide 6 fibers with flame retardant property is of great significance.
Chinese patent CN109971166A discloses a flame-retardant polyamide 6 resin and a preparation method thereof, wherein the flame-retardant polyamide 6 passes through the V-0 flame-retardant grade of UL-94 by the compound addition of polyhydroxy-substituted aromatic Schiff base and ammonium polyphosphate with high polymerization degree, the dripping is prevented, and the rigidity (the tensile strength is 61.3MPa) of pure polyamide 6 is kept; however, the addition amount of the flame retardant is up to 20 wt%, and spinning cannot be performed. It is known that the properties of polyamide 6 and the subsequent spinning process are strongly influenced by a larger amount of flame retardant.
Chinese patent CN104762689A discloses a preparation method of a copolymer flame-retardant polyamide 6 fiber, comprising the steps of reacting hydroxymethyl phenyl hypophosphorous acid, thionyl chloride and ether in a reaction kettle to obtain chloromethyl phenyl hypophosphorous acid, introducing ammonia gas into a sodium hydroxide solution of the chloromethyl phenyl hypophosphorous acid to obtain an aminomethyl phenyl hypophosphorous acid flame retardant, copolymerizing the flame retardant and caprolactam to obtain a flame-retardant polyamide 6 resin, and finally preparing the flame-retardant polyamide 6 fiber through melt spinning. When 0.5 to 15 wt% of flame retardant is added, the monofilament breaking strength is 2.5 to 5.0cN/tex, and the Limiting Oxygen Index (LOI) is 30 to 35. The fiber has good flame retardant effect, but the technological process from the synthesis of the flame retardant to the copolymerization is complex, and the application range is narrow.
In conclusion, in the process of preparing polyamide 6 fiber, an efficient and stable flame retardant is required to be sought, the addition amount of the flame retardant is reduced, the interface compatibility is improved, and the influence on the mechanical property of the fiber is reduced; and secondly, the spinning process of the flame-retardant polyamide 6 fiber needs to be optimized, the flow is simplified, and the controllable preparation of the flame-retardant polyamide 6 fiber is realized.
Disclosure of Invention
The invention aims to solve the technical problem of providing a preparation method of a flame-retardant polyamide 6 fiber based on a phosphorus-nitrogen synergistic flame retardant, so as to overcome the defects of poor spinning performance and mechanical performance and the like of the flame-retardant polyamide 6 fiber in the prior art.
The invention provides a preparation method of a flame-retardant polyamide 6 fiber based on a phosphorus-nitrogen synergistic flame retardant, which comprises the following steps:
(1) mixing the phosphorus-nitrogen synergistic flame retardant and polyamide 6 slices, feeding the mixture into a double-screw extruder, and pelletizing to obtain flame-retardant polyamide 6 master batches, wherein the phosphorus-nitrogen synergistic flame retardant has a chemical structural formula as follows:
in the formula R1、R2Including a hydrogen atom, a cyano group or a methyl group; r3、R4Including a hydrogen atom, a phenyl group or a methyl group;
(2) and (2) mixing the flame-retardant polyamide 6 master batch and the polyamide 6 slices in the step (1), drying, and performing melt extrusion, cooling, oiling, drafting and winding on the obtained slices to obtain the flame-retardant polyamide 6 fiber.
Preferably, the weight ratio of the phosphorus-nitrogen synergistic flame retardant to the polyamide 6 slices in the step (1) is 35-45: 55-65.
Preferably, the method for preparing the phosphorus-nitrogen synergistic flame retardant in the step (1) comprises the following steps: dissolving benzaldehyde containing a cyano group or a derivative thereof and benzimidazole containing an amino group or a derivative thereof in an organic solvent 1 in a molar ratio of 0.8: 1-1.5: 1, dropping a catalyst, and performing an aldehyde-amine condensation reaction at 50-90 ℃ for 5-9 hours; dispersing the obtained Schiff base intermediate into an organic solvent 2, adding 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO, and carrying out addition reaction at 50-90 ℃ for 1-12 h to obtain the Schiff base intermediate, wherein the molar ratio of the Schiff base intermediate to the DOPO is 0.8-1.2: 0.8-1.2.
Preferably, the benzaldehyde containing a cyano group or a derivative thereof comprises one or more of p-cyanobenzaldehyde and 4-formaldehyde-2, 6-dimethylbenzonitrile.
Preferably, the benzimidazole containing the amino group or the derivative thereof comprises one or more of 2-aminobenzimidazole and 2-amino-5-methylbenzimidazole.
Preferably, the organic solvent 1 and the organic solvent 2 comprise one or more of methanol, ethanol and N, N-dimethylformamide.
Preferably, the catalyst comprises one or more of hydrochloric acid, hydrofluoric acid and glacial acetic acid.
Preferably, the mass of the organic solvent 1 is 4 to 22 times of the total mass of the benzaldehyde containing a cyano group or the derivative thereof and the benzimidazole containing an amino group or the derivative thereof.
Preferably, the mass of the catalyst is 0.05-0.6 times of the total mass of the benzaldehyde containing a cyano group or the derivative thereof and the benzimidazole containing an amino group or the derivative thereof.
Preferably, the mass of the organic solvent 2 is 4-12 times of the total mass of the Schiff base intermediate and the DOPO.
Preferably, the temperature of the zones I, II, III, IV and V in the double-screw extruder in the step (1) is 230-260 ℃, and the rotating speed of the double screws is 4-10 rpm.
Preferably, the drying in step (2) is vacuum drying, and the process parameters of the vacuum drying are as follows: and the temperature of the drum drying box is 120-150 ℃, and the time is 24-48 h until the water content of the slices is lower than 100 ppm.
Preferably, the weight ratio of the flame-retardant polyamide 6 master batch to the polyamide 6 chip in the step (2) is 10-20: 80-90.
Preferably, the melt spinning in the step (2) is: feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box body through a screw, and spraying a melt out of a spinneret plate to enter a spinning channel.
Preferably, the melt spinning process parameters in the step (2) are as follows: the temperature of the twin-screw I, II and III zones of the spinning machine is 230-280 ℃, the temperature of the metering pump is 230-280 ℃, the temperature of the pipeline is 230-280 ℃, the temperature of the box body is 230-280 ℃, the rotating speed of the metering pump is 8-20 Hz, the temperature of the cross air blowing is 10-20 ℃, the wind speed is 0.1-1 m/s, the specification of a spinneret plate is 12-36 holes, and the hole diameter is 0.2-0.5 mu m.
Preferably, the oiling process parameters in the step (2) are as follows: the mass flow rate of the oil pump is 1-2 kg/h.
Preferably, the drawing in the step (2) is performed by using a godet hot roller, the temperature of the godet hot roller GR1 is 40-100 ℃, the rotating speed is 200-800 m/min, the temperature of the GR2 is 80-160 ℃, the rotating speed is 500-3200 m/min, and the drawing multiple is 2.5-4.0 times.
The invention also provides the flame-retardant polyamide 6 fiber prepared by the preparation method.
The invention also provides application of the flame-retardant polyamide 6 fiber in clothing, cables or silk screens.
The C ═ N and-NH of the benzimidazole structure in the phosphorus-nitrogen synergistic flame retardant can form hydrogen bonds with amido bonds in the main chain of polyamide 6, so that the flame retardant is uniformly distributed, broken ends caused by uneven distribution can be reduced, the flame retardant has high flame retardant efficiency, the addition amount can be reduced, and the loss of the mechanical properties of the fibers is minimized through the two modes. By adjusting the spinning, cooling and oiling processes, the problems of adhesion, much hairiness and incapability of unwinding of the flame-retardant polyamide 6 fiber are solved, and the flame-retardant polyamide 6 fiber with excellent flame retardant property and mechanical property is finally prepared.
Advantageous effects
(1) According to the invention, the C ═ N, -NH of the benzimidazole structure in the phosphorus-nitrogen synergistic flame retardant and the amido bond in the polyamide 6 main chain form hydrogen bond acting force, so that the distribution uniformity of the flame retardant is improved, the weak nodes of the fiber are reduced, and the end breakage is not easy to occur in the spinning process.
(2) According to the invention, through regulating and controlling the cross-blowing and oiling processes, the fibers are rapidly and uniformly cooled and bundled, the adhesion and hairiness are reduced, and the fiber unwinding and the subsequent processing are facilitated.
(3) The breaking strength of the flame-retardant polyamide 6 fiber prepared by the invention can reach 3.52 +/-0.06 cN/dtex, the elongation at break reaches 25.6 +/-0.8%, and the mechanical property is excellent.
(4) In a vertical combustion behavior test, the subsequent combustion time after leaving fire of the flame-retardant polyamide 6 fiber prepared by the invention is reduced to 2s from 20s of the polyamide 6 fiber, the number of molten drops is reduced to only 1 drop from 12 drops of the polyamide 6 fiber, and the flame retardant property is excellent.
Drawings
FIG. 1 is a nuclear magnetic diagram of a phosphorus-nitrogen-based flame retardant of the present invention.
FIG. 2 is a drawing of a flame-retardant polyamide 6 fiber according to the invention.
FIG. 3 is a graph showing the tensile properties of the flame retardant polyamide 6 fiber in example 1 of the present invention.
FIG. 4 is a vertical burning test chart of the flame-retardant polyamide 6 fiber bundle in example 1 of the present invention.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
The reagents involved in the invention are all reagent grade and are directly used without purification.
The examples relate to parts by weight.
The test standard of the invention is GB/T14344-2008 for breaking strength and breaking elongation, and the test standard of the invention is ASTM D6413 for vertical burning.
Example 1
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 13.1g of p-cyanobenzaldehyde and 10.2g of 2-aminobenzimidazole were dissolved in 200mL of methanol, 4mL of hydrofluoric acid was then dropped thereto, and the solution was heated to 60 ℃ and maintained for 9 hours, cooled, then precipitated in deionized water, filtered, and vacuum-dried to obtain an intermediate. 12.4g of the intermediate was dispersed with 200mL of methanol and poured into a three-necked flask, and then 9.7g of DOPO was added, heated to 80 ℃ and refluxed for 5 hours, filtered, washed 3 times with methanol, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was 462 by high resolution mass spectrometry, and its nuclear magnetic spectrum is shown in FIG. 1, 5.84ppm corresponds to the hydrogen proton peak on CH-in P-C-N, and its peak area, the residual peak area is 1:16 (-the hydrogen proton peak on NH can not be detected), consistent with the molecular structure, it can be confirmed that it was successfully synthesized.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V are 230 ℃, 235 ℃ and the screw rotation speed is 4 rpm.
3. Spinning
And mixing 15 parts of flame-retardant polyamide 6 master batch and 85 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 120 ℃ in a drum drying box for 48 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.2 mu m; the temperature of the twin-screw I, II and III zones of the spinning machine is 260 ℃, the temperature of the metering pump is 265 ℃, the temperature of the pipeline is 265 ℃, the temperature of the box body is 270 ℃, and the rotating speed of the metering pump is 12 Hz; the temperature of the cross air blowing is 10 ℃, and the air speed is 0.2 m/s; the mass flow rate of the oil agent pump is 1 kg/h; the temperature of the godet hot roller GR1 is 40 ℃, the rotating speed is 800m/min, the temperature of GR2 is 100 ℃, the rotating speed is 3200m/min, and the drawing multiple is 4.0 times.
As shown in FIG. 3, the breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 3.52 +/-0.06 cN/dtex, and the elongation at break is 25.6 +/-0.8%; as shown in fig. 4, in the vertical burning behavior test, the flame-retardant polyamide 6 fiber obtained had a 2s post-flaming time from the fire, and the number of molten droplets was only 1 droplet.
Example 2
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 15.9g of 4-carboxaldehyde-2, 6-dimethylbenzonitrile and 9.2g of 2-aminobenzimidazole were dissolved in 200mL of methanol, then 5mL of hydrofluoric acid was dropped thereto, the solution was heated to 70 ℃ and kept for 6 hours, cooled, then precipitated in deionized water, filtered, and vacuum-dried to obtain an intermediate. 15.0g of the intermediate was dispersed with 200mL of methanol and poured into a three-necked flask, then 10.8g of DOPO was added, heated to 70 ℃ under reflux for 2 hours, filtered, washed 4 times with methanol, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry to be 490.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V were 240 ℃, 230 ℃, 240 ℃ and the screw rotation speed was 6 rpm.
3. Spinning
Mixing 10 parts of flame-retardant polyamide 6 master batch and 90 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 130 ℃ in a drum drying box for 48 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.2 mu m; the temperature of the twin-screw I, II and III zones of the spinning machine is 255 ℃, 255 ℃ and 255 ℃, the temperature of the metering pump is 260 ℃, the temperature of the pipeline is 265 ℃, the temperature of the box body is 265 ℃ and the rotating speed of the metering pump is 12 Hz; the temperature of the cross air blowing is 16 ℃, and the air speed is 0.8 m/s; the mass flow rate of the oil agent pump is 1.5 kg/h; the temperature of the godet hot roller GR1 is 60 ℃, the rotating speed is 400m/min, the temperature of the GR2 is 120 ℃, the rotating speed is 1400m/min, and the drawing multiple is 3.5 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 3.25 +/-0.09 cN/dtex, the elongation at break is 29.5 +/-1.2%, and in a vertical burning behavior test, the subsequent burning time of the fiber after leaving the fire is 4s, and only 1 droplet of molten drops exists.
Example 3
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 13.1g of p-cyanobenzaldehyde and 15.8g of 2-amino-5-methylbenzimidazole were dissolved in 250mL of N, N-dimethylformamide, and then 4mL of glacial acetic acid was dropped thereto, and the solution was heated to 70 ℃ and kept for 6 hours, cooled, precipitated in deionized water, filtered and vacuum-dried to obtain an intermediate. 13.0g of the intermediate was dispersed in 250ml of N, N-dimethylformamide and poured into a three-necked flask, and then 11.8g of DOPO was added, heated to 70 ℃ for reflux for 8 hours, filtered, washed 5 times with N, N-dimethylformamide, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry as 476.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V are 230 ℃, 235 ℃ and the screw rotation speed is 6 rpm.
3. Spinning
And mixing 20 parts of flame-retardant polyamide 6 master batch and 80 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 120 ℃ in a drum drying box for 48 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 24 holes, and the aperture is 0.4 mu m; the temperature of the double screw I, II and III zones of the spinning machine is 255 ℃, the temperature of the metering pump is 255 ℃, the temperature of the pipeline is 260 ℃, the temperature of the box body is 260 ℃, and the rotating speed of the metering pump is 8 Hz; the temperature of the cross air blowing is 10 ℃, and the air speed is 0.4 m/s; the mass flow rate of the oil agent pump is 2 kg/h; the temperature of the godet hot roller GR1 is 50 ℃, the rotating speed is 200m/min, the temperature of the GR2 is 90 ℃, the rotating speed is 500m/min, and the drawing multiple is 2.5 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 2.86 +/-0.12 cN/dtex, the elongation at break is 38.6 +/-1.5%, and in a vertical burning behavior test, the subsequent burning time of the fiber after leaving the fire is 2s, and only 1 droplet of molten drops exists.
Example 4
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 15.9g of 4-carboxaldehyde-2, 6-dimethylbenzonitrile and 10.2g of 2-amino-5-methylbenzimidazole were dissolved in 150mL of ethanol, then 4mL of glacial acetic acid was dropped thereto, the solution was heated to 80 ℃ and kept for 6 hours, and after cooling, precipitation in deionized water, filtration and vacuum drying were carried out to obtain an intermediate. 13.8g of the intermediate was dispersed in 150mL of ethanol and poured into a three-necked flask, and then 9.7g of DOPO was added, heated to 80 ℃ and refluxed for 6 hours, filtered, washed with ethanol 3 times, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry to be 504.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V are 250 ℃, 240 ℃ and the screw rotation speed is 4 rpm.
3. Spinning
And mixing 12 parts of flame-retardant polyamide 6 master batch and 88 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 140 ℃ in a drum drying box for 36 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.2 mu m; the temperature of the twin-screw I, II and III zones of the spinning machine is 260 ℃, the temperature of the metering pump is 265 ℃, the temperature of the pipeline is 265 ℃, the temperature of the box body is 265 ℃ and the rotating speed of the metering pump is 20 Hz; the temperature of the cross air blowing is 20 ℃, and the air speed is 1 m/s; the mass flow rate of the oil agent pump is 1.5 kg/h; the temperature of the godet hot roller GR1 is 100 ℃, the rotating speed is 600m/min, the temperature of the GR2 is 160 ℃, the rotating speed is 1920m/min, and the drawing multiple is 3.2 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 3.40 +/-0.04 cN/dtex, the elongation at break is 30.1 +/-0.8%, and in a vertical burning behavior test, the subsequent burning time of the fiber after leaving the fire is 4s, and only 1 droplet of molten drops exists.
Example 5
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 13.1g of p-cyanobenzaldehyde and 11.8g of 2-aminobenzimidazole were dissolved in 180mL of methanol, and then 5mL of hydrochloric acid was dropped thereto, and the solution was heated to 60 ℃ and maintained for 8 hours, cooled, precipitated in deionized water, filtered, and vacuum-dried to obtain an intermediate. 12.0g of the intermediate was dispersed with 180mL of methanol and poured into a three-necked flask, and then 9.7g of DOPO was added, heated to 60 ℃ and refluxed for 8 hours, filtered, washed 3 times with methanol, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry as 462.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V are 255 ℃, 260 ℃ and the screw rotation speed is 10 rpm.
3. Spinning
And mixing 14 parts of flame-retardant polyamide 6 master batch and 86 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 150 ℃ in a drum drying box for 24 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 12 holes, and the aperture is 0.5 mu m; the temperature of the twin-screw I, II and III zones of the spinning machine is 255 ℃, 255 ℃ and 260 ℃, the temperature of the metering pump is 260 ℃, the temperature of the pipeline is 255 ℃, the temperature of the box body is 255 ℃, and the rotating speed of the metering pump is 10 Hz; the temperature of the cross air blowing is 15 ℃, and the air speed is 0.5 m/s; the mass flow rate of the oil agent pump is 1 kg/h; the temperature of the godet hot roller GR1 is 50 ℃, the rotating speed is 300m/min, the temperature of GR2 is 120 ℃, the rotating speed is 960m/min, and the drawing multiple is 3.2 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 3.21 +/-0.06 cN/dtex, the elongation at break is 32.4 +/-1.2%, and in a vertical combustion behavior test, the subsequent combustion time of the fiber away from the fire is 3s, and only 1 droplet of molten drops exists.
Example 6
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 15.9g of 4-carboxaldehyde-2, 6-dimethylbenzonitrile and 9.4g of 2-aminobenzimidazole were dissolved in 200mL of ethanol, then 6mL of hydrofluoric acid was dropped thereto, and the solution was heated to 90 ℃ and maintained for 5 hours, cooled, precipitated in deionized water, filtered, and vacuum-dried to obtain an intermediate. 15.3g of the intermediate was dispersed with 200mL of ethanol and poured into a three-necked flask, then 10.6g of DOPO was added, heated to 90 ℃ and refluxed for 1 hour, filtered, washed 4 times with ethanol, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry to be 490.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V are 260 ℃, 255 ℃ and 255 ℃, and the rotation speed of the screws is 8 rpm.
3. Spinning
And mixing 16 parts of flame-retardant polyamide 6 master batch and 84 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 150 ℃ in a drum drying box for 24 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.2 mu m; the temperature of the twin-screw I, II and III zones of the spinning machine is 270 ℃, the temperature of the metering pump is 270 ℃, the temperature of the pipeline is 260 ℃, the temperature of the box body is 260 ℃ and the rotating speed of the metering pump is 14 Hz; the temperature of the cross air blowing is 16 ℃, and the air speed is 0.8 m/s; the mass flow rate of the oil agent pump is 1.5 kg/h; the temperature of the godet hot roller GR1 is 40 ℃, the rotating speed is 600m/min, the temperature of GR2 is 80 ℃, the rotating speed is 1800m/min, and the drawing multiple is 3.0 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 3.18 +/-0.09 cN/dtex, the elongation at break is 30.7 +/-1.3%, and in a vertical combustion behavior test, the subsequent combustion time of 2s after leaving fire is only 1 drop.
Example 7
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 13.1g of p-cyanobenzaldehyde and 14.5g of 2-amino-5-methylbenzimidazole were dissolved in 200mL of N, N-dimethylformamide, and then 6mL of glacial acetic acid was dropped thereto, and the solution was heated to 50 ℃ and kept for 9 hours, cooled, precipitated in deionized water, filtered and vacuum-dried to obtain an intermediate. 13.4g of the intermediate was dispersed in 200ml of N, N-dimethylformamide and poured into a three-necked flask, and then 11.9g of DOPO was added, heated to 50 ℃ under reflux for 12 hours, filtered, washed 5 times with N, N-dimethylformamide, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry as 476.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V were 240 ℃, 240 ℃ and 240 ℃, and the screw rotation speed was 6 rpm.
3. Spinning
And mixing 18 parts of flame-retardant polyamide 6 master batch and 82 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 130 ℃ in a drum drying box for 36 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.2 mu m; the temperature of the double screw I, II and III zones of the spinning machine is 240 ℃, the temperature of the metering pump is 250 ℃, the temperature of the pipeline is 245 ℃, the temperature of the box body is 245 ℃, and the rotating speed of the metering pump is 8 Hz; the temperature of the cross air blowing is 10 ℃, and the air speed is 0.4 m/s; the mass flow rate of the oil agent pump is 2 kg/h; the temperature of the godet hot roller GR1 is 50 ℃, the rotating speed is 400m/min, the temperature of GR2 is 120 ℃, the rotating speed is 1120m/min, and the drawing multiple is 2.8 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 2.93 +/-0.08 cN/dtex, the elongation at break is 35.2 +/-1.3%, and in the vertical combustion behavior test, the subsequent combustion time of 2s after leaving fire is only 1 drop.
Example 8
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 15.9g of 4-carboxaldehyde-2, 6-dimethylbenzonitrile and 12.4g of 2-amino-5-methylbenzimidazole were dissolved in 150mL of ethanol, then 4mL of hydrofluoric acid was dropped thereto, the solution was heated to 75 ℃ and maintained for 8 hours, and after cooling, precipitation in deionized water, filtration and vacuum drying were carried out to obtain an intermediate. 13.9g of the intermediate was dispersed in 150mL of ethanol and poured into a three-necked flask, and then 9.2g of DOPO was added, heated to 75 ℃ and refluxed for 8 hours, filtered, washed 3 times with ethanol, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry to be 504.
2. Granulating
40 parts of phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 slices are mixed, fed into a double-screw extruder and granulated by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V were 240 ℃, 245 ℃ and the screw rotation speed was 6 rpm.
3. Spinning
And mixing 15 parts of flame-retardant polyamide 6 master batch and 85 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 120 ℃ in a drum drying box for 48 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.4 mu m; the temperatures of the twin-screw I, II and III zones of the spinning machine are 265 ℃, 265 ℃ and 265 ℃, the temperature of the metering pump is 275 ℃, the temperature of the pipeline is 275 ℃, the temperature of the box body is 275 ℃, and the rotating speed of the metering pump is 20 Hz; the temperature of the cross air blowing is 12 ℃, and the air speed is 0.3 m/s; the mass flow rate of the oil agent pump is 1.5 kg/h; the temperature of the godet hot roller GR1 is 60 ℃, the rotating speed is 450m/min, the temperature of GR2 is 100 ℃, the rotating speed is 1710m/min, and the drawing multiple is 3.8 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained in the embodiment can reach 3.34 +/-0.07 cN/dtex, the elongation at break is 29.0 +/-1.0%, and in a vertical burning behavior test, the subsequent burning time of the fiber after leaving the fire is 2s, and only 1 droplet of molten drops exists.
Comparative example 1
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 13.1g of p-cyanobenzaldehyde and 7.0g of aniline were dissolved in 200mL of methanol, 4mL of hydrofluoric acid was then dropped thereto, the solution was heated to 60 ℃ and maintained for 9 hours, cooled, precipitated in deionized water, filtered and vacuum-dried to obtain an intermediate. 12.4g of the intermediate was dispersed with 200mL of methanol and poured into a three-necked flask, and then 9.7g of DOPO was added, heated to 80 ℃ and refluxed for 5 hours, filtered, washed 3 times with methanol, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry to be 422.
2. Granulating
And (3) mixing 40 parts of the phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 chips, feeding the mixture into a double-screw extruder, and granulating the mixture by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V are 230 ℃, 235 ℃ and the screw rotation speed is 4 rpm.
3. Spinning
And mixing 15 parts of flame-retardant polyamide 6 master batch and 85 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 120 ℃ in a drum drying box for 48 hours until the water content of the slices is lower than 100 ppm. And then feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box body through a screw, spraying out a melt through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.2 mu m; the temperature of the twin-screw I, II and III zones of the spinning machine is 260 ℃, the temperature of the metering pump is 265 ℃, the temperature of the pipeline is 265 ℃, the temperature of the box body is 270 ℃, and the rotating speed of the metering pump is 12 Hz; the temperature of the cross air blowing is 10 ℃, and the air speed is 0.2 m/s; the mass flow rate of the oil agent pump is 1 kg/h; the temperature of the godet hot roller GR1 is 40 ℃, the rotating speed is 200m/min, the temperature of the GR2 is 100 ℃, the rotating speed is 500m/min, and the drawing multiple is 2.5 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained by the comparative example can reach 1.98 +/-0.26 cN/dtex, and the elongation at break is 11.4 +/-1.8%; in the vertical burning behavior test, the flame-retardant polyamide 6 fiber obtained in the comparative example left the fire for a subsequent burning time of 5s and 3 drops. Therefore, when the flame retardant does not contain a benzimidazole structure, the action force of hydrogen bonds formed by C ═ N and-NH of the benzimidazole structure and amido bonds in the main chain of the polyamide 6 cannot be utilized, the distribution uniformity of the flame retardant is reduced, the polyamide 6 fiber is easy to break in the spinning process, and the loss of mechanical properties of the fiber is large.
Comparative example 2
1. Preparation of phosphorus-nitrogen synergistic flame retardant
In a three-necked flask equipped with a nitrogen inlet, a reflux condenser and a magnetic stirrer, 13.1g of p-cyanobenzaldehyde and 10.2g of 2-aminobenzimidazole were dissolved in 200mL of methanol, 4mL of hydrofluoric acid was then dropped thereto, and the solution was heated to 60 ℃ and maintained for 9 hours, cooled, then precipitated in deionized water, filtered, and vacuum-dried to obtain an intermediate. 12.4g of the intermediate was dispersed with 200mL of methanol and poured into a three-necked flask, and then 9.7g of DOPO was added, heated to 80 ℃ and refluxed for 5 hours, filtered, washed 3 times with methanol, and vacuum-dried to obtain a white powder. The relative molecular mass of the white powder was determined by high resolution mass spectrometry as 462.
2. Granulating
And (3) mixing 40 parts of the phosphorus-nitrogen synergistic flame retardant and 60 parts of polyamide 6 chips, feeding the mixture into a double-screw extruder, and granulating the mixture by a granulator to obtain the flame-retardant polyamide 6 master batch. The main technological parameters are as follows: the temperatures of the twin-screw zones I, II, III, IV and V are 230 ℃, 235 ℃ and the screw rotation speed is 4 rpm.
3. Spinning
And mixing 15 parts of flame-retardant polyamide 6 master batch and 85 parts of polyamide 6 slices, and then carrying out vacuum drying at the temperature of 120 ℃ in a drum drying box for 48 hours until the water content of the slices is lower than 100 ppm. And then, feeding the slices into a feed inlet of a spinning machine, feeding the slices into a spinning box through a screw, spraying the melt out through a spinneret plate, feeding the melt into a spinning channel, and cooling, oiling, drawing by a godet hot roller and winding to obtain the flame-retardant polyamide 6 fiber. The main technological parameters are as follows: the spinneret plate has 36 holes, and the aperture is 0.2 mu m; the temperature of the twin-screw I, II and III zones of the spinning machine is 260 ℃, the temperature of the metering pump is 265 ℃, the temperature of the pipeline is 265 ℃, the temperature of the box body is 270 ℃, and the rotating speed of the metering pump is 12 Hz; the temperature of the cross air blowing is 25 ℃, and the air speed is 0.05 m/s; the mass flow rate of the oil agent pump is 0.5 kg/h; the temperature of the godet hot roller GR1 is 40 ℃, the rotating speed is 200m/min, the temperature of the GR2 is 100 ℃, the rotating speed is 500m/min, and the drawing multiple is 2.5 times.
The breaking strength of the flame-retardant polyamide 6 fiber obtained by the comparative example can reach 2.26 +/-0.06 cN/dtex, and the elongation at break is 21.6 +/-0.9%; in the vertical burning behavior test, the flame-retardant polyamide 6 fiber obtained in the comparative example has a 2s follow-up burning time after leaving the fire, and the molten drop is only 1 drop. Therefore, improper cross air blowing and oiling processes can cause the problems of untimely fiber cooling, easy adhesion, much hairiness and difficult unwinding in the spinning process, and finally destroy the mechanical properties of the fibers.
Claims (10)
1. A preparation method of flame-retardant polyamide 6 fiber based on phosphorus-nitrogen synergistic flame retardant comprises the following steps:
(1) mixing the phosphorus-nitrogen synergistic flame retardant and polyamide 6 slices, feeding the mixture into a double-screw extruder, and pelletizing to obtain flame-retardant polyamide 6 masterbatch, wherein the chemical structural formula of the phosphorus-nitrogen synergistic flame retardant is as follows:
in the formula R1、R2Including a hydrogen atom, a cyano group or a methyl group; r3、R4Including a hydrogen atom, a phenyl group or a methyl group;
(2) and (2) mixing the flame-retardant polyamide 6 master batch and the polyamide 6 slices in the step (1), drying, and performing melt extrusion, cooling, oiling, drafting and winding on the obtained slices to obtain the flame-retardant polyamide 6 fiber.
2. The preparation method according to claim 1, wherein the weight ratio of the phosphorus-nitrogen synergistic flame retardant to the polyamide 6 chip in the step (1) is 35-45: 55-65.
3. The preparation method according to claim 1, wherein the preparation method of the phosphorus-nitrogen synergistic flame retardant in the step (1) comprises the following steps: dissolving benzaldehyde containing cyano or derivatives thereof and benzimidazole containing amino or derivatives thereof in an organic solvent, dripping a catalyst, and carrying out an aldehyde-amine condensation reaction; dispersing the obtained Schiff base intermediate in an organic solvent, adding 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO, and performing addition reaction to obtain the Schiff base.
4. The preparation method according to claim 1, wherein the temperature of the zones I, II, III, IV and V in the twin-screw extruder in the step (1) is 230 to 260 ℃ and the rotation speed of the twin-screw extruder is 4 to 10 rpm.
5. The preparation method according to claim 1, wherein the weight ratio of the flame-retardant polyamide 6 masterbatch to the polyamide 6 chip in the step (2) is 10-20: 80-90.
6. The preparation method according to claim 1, wherein the melt spinning in the step (2) comprises the following process parameters: the temperature of the twin-screw I, II and III zones of the spinning machine is 230-280 ℃, the temperature of the metering pump is 230-280 ℃, the temperature of the pipeline is 230-280 ℃, the temperature of the box body is 230-280 ℃, the rotating speed of the metering pump is 8-20 Hz, the temperature of the cross air blowing is 10-20 ℃, the wind speed is 0.1-1 m/s, the specification of a spinneret plate is 12-36 holes, and the hole diameter is 0.2-0.5 mu m.
7. The preparation method according to claim 1, wherein the oiling process parameters in the step (2) are as follows: the mass flow rate of the oil pump is 1-2 kg/h.
8. The preparation method of claim 1, wherein the drawing in the step (2) is drawing by using a godet hot roller, the godet hot roller GR1 has a temperature of 40-100 ℃, a rotation speed of 200-800 m/min, GR2 has a temperature of 80-160 ℃, a rotation speed of 500-3200 m/min, and a drawing multiple of 2.5-4.0 times.
9. A flame-retardant polyamide 6 fiber prepared by the preparation method according to claim 1.
10. Use of the flame retardant polyamide 6 fiber according to claim 9 in garments, cables or screens.
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