CN115838978A

CN115838978A - Antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber and preparation method thereof

Info

Publication number: CN115838978A
Application number: CN202211727731.7A
Authority: CN
Inventors: 朱文统
Original assignee: Xuchang Hongyang Biochemical Industrial Development Co ltd
Current assignee: Xuchang Hongyang Biochemical Industrial Development Co ltd
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-03-24

Abstract

The invention provides an antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber and a preparation method thereof, and relates to the field of wig fibers. The sheath-core polyester-nylon composite wig fiber is prepared from the following components in parts by weight: 50-100 parts of modified antibacterial PA, 200-300 parts of PA, 20-40 parts of modified flame-retardant PET, 90-150 parts of PET, 1-5 parts of thermochromic microcapsule toner, 2-5 parts of auxiliary additive and 2-8 parts of dispersant. The sheath-core polyester-nylon composite wig fiber is prepared from an antibacterial sheath layer and a flame-retardant core layer, wherein the antibacterial sheath layer comprises two antibacterial components of nano copper-zinc oxide and graphene oxide, so that the attachment of bacteria on the wig fiber can be resisted, and the health in the aspect of antibiosis is reflected; CEPPA is introduced into the flame-retardant core layer to realize in-situ flame retardance, and an expandable graphite flame retardant is added to separate a fuel source from oxygen, and the flame retardant absorbs a large amount of heat in the expansion process, so that the surface cooling is facilitated, the flame-retardant effect is achieved, and the safety in the flame retardance aspect is reflected. The composite wig fiber obtained by the invention has flexibility and combing performance similar to that of human hair straightening, has excellent antibacterial and flame retardant properties, and has good market competitiveness.

Description

Antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber and preparation method thereof

Technical Field

The invention relates to the field of wig fibers, in particular to an antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber and a preparation method thereof.

Background

With the rapid development of economy and the improvement of living standard of people, the wig becomes a necessary ornament for people to pursue individuation, and factors such as the prevalence of quadratic cospelay culture, the top hot of alopecia and the like stimulate the production and manufacture of wig products. The appearance of the wig is paid public attention, and the wig industry develops rapidly in recent years and becomes a new fashion trend besides beauty. On the other hand, "hair loss in young people" becomes a topic of enthusiasm, making wigs one of the new needs to be consumed.

At present, the real hair is difficult to purchase, and the purchase price is high, so most wigs in the market at present are mainly artificial wigs made of synthetic materials, and the raw material base materials commonly used for preparing the wigs comprise polypropylene, polyamide, polyvinyl chloride, polyester and the like. The wig fiber has the advantages of low price, simple processing and the like, but the droplets formed during burning can be adhered to the skin to cause burn. In addition, in the wearing and using process of the wig, bacteria are easy to breed due to sweat, rainwater and the like which are directly or indirectly contacted with a human body and excreted, and along with the increase of the health attention degree of people, the antibacterial functional requirement is also provided for wig fibers, and the research and the production in the aspect are relatively deficient at present. A truly qualified and applicable wig not only has the characteristics of being colorful, unique in style, attractive, bright and fashionable, but also has the safety of flame retardance and bacteria resistance.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the antibacterial and flame-retardant sheath-core polyester-nylon composite wig fiber and the preparation method thereof, so that the composite wig fiber has the advantages of flame retardance, antibacterium and temperature-sensitive discoloration.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

an antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber is prepared from the following components in parts by weight: 50-100 parts of modified antibacterial PA, 200-300 parts of PA, 20-40 parts of modified flame-retardant PET, 90-150 parts of PET, 1-5 parts of thermochromic microcapsule toner, 2-5 parts of auxiliary additive and 2-8 parts of dispersant.

Preferably, the modified antibacterial PA is prepared from (100-140): (3-18): and (1-3) PA, nano copper-zinc oxide and graphene oxide.

Preferably, the modified antibacterial PA is prepared from (110-130): (8-18): and (2-3) PA, nano copper-zinc oxide and graphene oxide.

Preferably, the modified flame-retardant PET is blended in a molar ratio of (80-120): (2-5): (6-15) PET, 2-carboxyethylphenylphosphinic acid (CEPPA), and an expandable graphite flame retardant.

Preferably, the modified flame-retardant PET is blended in a molar ratio of (90-120): (3-5): (8-13) PET, CEPPA, expandable graphite flame retardant.

Preferably, the thermochromic microcapsule toner is prepared from a mixture of (2-12): (3-15): (5-18) urea-formaldehyde resin, bisphenol A, 2-phenylamino-3-methyl-6-dibutylfluorane.

Preferably, the auxiliary additive is one or more of calcium carbonate, mica powder, silica, talcum powder, silicon micropowder, titanium dioxide and glass beads.

Preferably, the dispersant is one of ethylene bis stearamide and barium stearate.

A preparation method of antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber comprises the following steps:

(1) Preparing the nano copper-zinc oxide composite antibacterial agent: ultrasonically dispersing 5.00g of nano zinc oxide into 100mL of deionized water, wherein the ultrasonic time is 40min, and the frequency is 45kHz; dissolving 0.5g of copper chloride dihydrate in deionized water to prepare a solution; refluxing and condensing a flask filled with nano zinc oxide and copper chloride dihydrate at 85 ℃, and dropwise adding 15mmol of ascorbic acid aqueous solution into the flask while stirring; stirring the mixed solution at 85 ℃ for 24 hours until a dark solution is obtained; washing the obtained product with absolute ethyl alcohol and deionized water, centrifuging, and freeze-drying to obtain the nano copper-zinc oxide composite antibacterial agent.

(2) Preparing modified antibacterial PA: mixing the components in a molar ratio of (100-140): (3-18): and (1) carrying out melt blending on the PA, the nano copper-zinc oxide and the graphene oxide in an open mill under the following conditions: the temperature is 170 ℃, and the time is 40min;

(3) Preparing a skin layer spinning solution: mixing the components in a molar ratio of (50-100): (200-300): (1-5): (1-3): (1-5) uniformly mixing the modified antibacterial PA and PA, the thermochromic microcapsule toner, the auxiliary additive and the dispersing agent;

(4) Preparing modified flame-retardant PET: preparing a molar ratio of (80-120): (2-5): (6-15) PET, CEPPA and expandable graphite flame retardant, copolymerizing the PET and the CEPPA, and melt-blending the copolymerized product and the expandable graphite flame retardant in an open mill under the following conditions: the temperature is 190 ℃, and the time is 30min;

(5) Preparing a core layer spinning solution: mixing the components in a molar ratio of (20-40): (90-150): (1-2): (1-3) uniformly mixing the modified flame-retardant PET, the auxiliary additive and the dispersing agent;

(6) Sheath-core composite spinning: spinning and forming the skin layer spinning solution and the core layer spinning solution in a skin-core bi-component spinning component with the coagulation bath temperature of 4 ℃ to obtain gel fiber;

(7) Carrying out wet-heat stretching and water washing on the gel fiber obtained in the step (5), wherein the total stretching multiple is 12-14 times, and the temperature is 50-90 ℃;

(8) Carrying out dry heat stretching on the gel fiber obtained in the step (6), wherein the temperature is 150-170 ℃, and the stretching ratio is 2;

(9) And (3) carrying out thermal relaxation treatment on the gel fiber obtained in the step (7), wherein the temperature is 220 ℃, and the relaxation rate is 50%.

(III) advantageous effects

(1) The modified antibacterial PA is prepared from PA, nano copper-zinc oxide and graphene oxide. The nano material has unique structural characteristics and can be used for preparing efficient and safe antibacterial agents. Meanwhile, the derivative of graphene, namely oxidized graphene can induce the oxidative stress of bacteria, so that the cell walls and cell membranes of the bacteria are directly damaged, and the bacteriostatic action is achieved.

(2) The modified flame-retardant PET is prepared by blending a product obtained by copolymerizing PET and CEPPA with an expandable graphite flame retardant. CEPPA is an environment-friendly flame retardant, is introduced into a PET molecular chain as a comonomer in an esterification stage, and is copolymerized with a PET monomer to prepare the flame-retardant PET, so that in-situ flame retardance can be realized. In addition, the product obtained after the copolymerization of PET and CEPPA and the expandable graphite flame retardant are subjected to melt blending, the expandable graphite flame retardant covers the surface of the polymer material, a fuel source is separated from oxygen, a large amount of heat is absorbed in the expansion process, the surface cooling is facilitated, and the flame retardant effect is achieved.

(3) The thermochromic microcapsule toner disclosed by the invention is composed of urea-formaldehyde resin, bisphenol A and 2-phenylamino-3-methyl-6-dibutylaminofluorane. The urea-formaldehyde resin is used as a microcapsule shell to wrap a color developing agent bisphenol A and a leuco agent 2-phenylamino-3-methyl-6-dibutylaminofluorane, so that the light sensitivity of the fiber can be well realized.

The sheath-core polyester-nylon composite wig fiber disclosed by the invention is prepared from the antibacterial sheath layer and the flame-retardant core layer, has the flexibility and the carding performance similar to those of straight hair of a real person, has excellent antibacterial and flame-retardant properties, and reflects the health and safety.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

An antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber is prepared from the following components in parts by weight:

100 parts of modified antibacterial PA, 280 parts of PA, 40 parts of modified flame-retardant PET, 140 parts of PET, 5 parts of thermochromic microcapsule toner, 5 parts of auxiliary additive and 8 parts of dispersing agent; the modified antibacterial PA is prepared from the following components in a molar ratio of 120:15:3, PA, nano copper-zinc oxide and graphene oxide; the modified flame-retardant PET is prepared from the following components in a molar ratio of 100:3:8 PET, CEPPA and expandable graphite flame retardant; the thermochromic microcapsule toner is prepared from the following components in a molar ratio of 12:10:18 of urea-formaldehyde resin, bisphenol A and 2-phenylamino-3-methyl-6-dibutylfluorane; the auxiliary additive is silicon dioxide; the dispersant is ethylene bis stearamide.

Example 2

50 parts of modified antibacterial PA, 200 parts of PA, 25 parts of modified flame-retardant PET, 90 parts of PET, 1 part of thermochromic microcapsule toner, 2 parts of auxiliary additive and 2 parts of dispersing agent; the modified antibacterial PA is prepared from the following components in a molar ratio of 100:12:1 of PA, nano copper-zinc oxide and graphene oxide; the modified flame-retardant PET is prepared from the following components in a molar ratio of 110:2:10 PET, CEPPA, expandable graphite flame retardant; the thermochromic microcapsule toner is prepared from the following components in a molar ratio of 9:8:14 urea-formaldehyde resin, bisphenol A, 2-phenylamino-3-methyl-6-dibutylfluorane; the auxiliary additive is silicon dioxide; the dispersant is barium stearate.

Example 3

80 parts of modified antibacterial PA, 240 parts of PA, 25 parts of modified flame-retardant PET, 130 parts of PET, 4 parts of thermochromic microcapsule toner, 3 parts of auxiliary additive and 3 parts of dispersing agent; the modified antibacterial PA comprises the following components in a molar ratio of 110:5:1 of PA, nano copper-zinc oxide and graphene oxide; the modified flame-retardant PET is prepared from the following components in a molar ratio of 110:4:11 PET, CEPPA and expandable graphite flame retardant; the thermochromic microcapsule toner is prepared from the following components in a molar ratio of 5:7:12 of urea resin, bisphenol A and 2-phenylamino-3-methyl-6-dibutylfluorane; the auxiliary additive is mica powder; the dispersant is barium stearate.

Example 4

60 parts of modified antibacterial PA (polyamide), 220 parts of PA (polyamide), 28 parts of modified flame-retardant PET (polyethylene terephthalate), 110 parts of PET (polyethylene terephthalate), 2 parts of thermochromic microcapsule toner, 2 parts of auxiliary additive and 2 parts of dispersing agent; the modified antibacterial PA is prepared from the following components in a molar ratio of 100:4:2, PA, nano copper-zinc oxide and graphene oxide; the modified flame-retardant PET is prepared from the following components in a molar ratio of 80:3:10 PET, CEPPA, expandable graphite flame retardant; the thermochromic microcapsule toner is prepared from the following components in a molar ratio of 4:10:15 of urea-formaldehyde resin, bisphenol A and 2-phenylamino-3-methyl-6-dibutylfluorane; the auxiliary additive is mica powder; the dispersing agent is ethylene bis stearamide.

Example 5

90 parts of modified antibacterial PA, 260 parts of PA, 35 parts of modified flame-retardant PET, 140 parts of PET, 4 parts of thermochromic microcapsule toner, 5 parts of auxiliary additive and 8 parts of dispersing agent; the modified antibacterial PA comprises the following components in a molar ratio of 130:15:3, PA, nano copper-zinc oxide and graphene oxide; the modified flame-retardant PET is prepared from the following components in a molar ratio of 80:3:7 PET, CEPPA and expandable graphite flame retardant; the thermochromic microcapsule toner is prepared from the following components in a molar ratio of 10:7:8 of urea resin, bisphenol A and 2-phenylamino-3-methyl-6-dibutylfluorane; the auxiliary additive is calcium carbonate; the dispersant is ethylene bis stearamide.

Example 6

70 parts of modified antibacterial PA, 240 parts of PA, 30 parts of modified flame-retardant PET, 125 parts of PET, 2 parts of thermochromic microcapsule toner, 3 parts of auxiliary additive and 5 parts of dispersing agent; the modified antibacterial PA is prepared from the following components in a molar ratio of 120:12:2, PA, nano copper-zinc oxide and graphene oxide; the modified flame-retardant PET is prepared from the following raw materials in a molar ratio of 105:4:11 PET, CEPPA and expandable graphite flame retardant; the thermochromic microcapsule toner is prepared from the following components in a molar ratio of 6:9:12 of urea resin, bisphenol A and 2-phenylamino-3-methyl-6-dibutylfluorane; the auxiliary additive is calcium carbonate; the dispersant is ethylene bis stearamide.

(1) Preparing modified antibacterial PA: mixing the components in a molar ratio of 120:12:2, carrying out melt blending on the PA, the nano copper-zinc oxide and the graphene oxide in an open mill under the following conditions: the temperature is 170 ℃, and the time is 40min;

(2) Preparing a skin layer spinning solution: mixing the following raw materials in parts by mass as 70:240:2:2:3, uniformly mixing the modified antibacterial PA and PA, the thermochromic microcapsule toner, the auxiliary additive and the dispersing agent;

(3) Preparing modified flame-retardant PET: according to the molar ratio of 105:4: taking PET, CEPPA and an expandable graphite flame retardant, and carrying out melt blending on a product obtained by copolymerizing the PET and the CEPPA and the expandable graphite flame retardant in an open mill under the following conditions: the temperature is 190 ℃, and the time is 30min;

(4) Preparing a core layer spinning solution: the weight portion ratio is 30:125:1:2, uniformly mixing the modified flame-retardant PET, the auxiliary additive and the dispersing agent;

(5) Sheath-core composite spinning: spinning and molding the skin layer spinning solution and the core layer spinning solution in a skin-core bi-component spinning assembly with the coagulation bath temperature of 4 ℃ to obtain gel fibers;

(6) Carrying out wet-hot stretching and water washing on the gel fiber obtained in the step (5), wherein the total stretching multiple is 12 times, and the temperature is 70 ℃;

(7) Carrying out dry heat stretching on the gel fiber obtained in the step (6), wherein the temperature is 150 ℃, and the stretching ratio is 2;

(8) And (3) carrying out thermal relaxation treatment on the gel fiber obtained in the step (7), wherein the temperature is 220 ℃, and the relaxation rate is 50%.

Test example 1

Physical Properties of composite wig fibers according to examples 1-6 of the present invention

In this test, the diameter, breaking strength and breaking elongation of the wig fibers obtained in examples 1 to 6 were measured with respect to straight human hair, and the quality, flexibility and combing property of each of the wig fibers were evaluated by sensory evaluation, and the results are shown in Table 1.

As can be seen from Table 1, the wig fibers prepared in examples 1-6 have no significant difference from the real hair straightening in terms of diameter, quality, flexibility and combing performance; the breaking strength of the wig fibers prepared in examples 1-6 was slightly improved as compared with the straight hair of a real person; the data show that the wig fiber has flexibility and combing performance similar to that of real human hair and good physical performance.

Table 1 physical property testing of examples 1-6 with real human hair

Test example 2

Cortex antibacterial Performance test

To further illustrate the cortex antibacterial performance of the sheath-core polyester-nylon composite wig fiber of the present invention, the following experiment was performed. And (3) placing the bacterial liquid with a certain concentration on the sample, culturing for a certain time, and measuring the number of the residual bacteria to obtain the antibacterial rate of the composite material. The strains are respectively staphylococcus aureus, escherichia coli and candida albicans. The test is divided into 4 groups, group 1 has a complete composite fiber cortex component of the invention, group 2 lacks a graphene oxide component, group 3 lacks a nano-copper-zinc oxide component, group 4 lacks a graphene oxide and nano-copper-zinc oxide component, and the raw materials and parts of each group are shown in table 2.

TABLE 2 raw materials and parts of wig fibers of each group

Group 4 above modified antibacterial PA was prepared as described in example 6; weighing the modified antibacterial PA, the thermochromic microcapsule toner, the calcium carbonate and the ethylene bis-stearamide according to the parts by weight in the table 1, crushing raw materials, granulating, extruding, heat setting, collecting filaments and packaging to obtain the four groups of wig fibers.

The groups 2 and 3 lack graphene oxide or nano copper-zinc oxide components respectively, and as can be seen from table 3, the inhibition rates of the wig fibers prepared by the groups 2 and 3 on staphylococcus aureus, escherichia coli and candida albicans are obviously reduced, and the antibacterial property is poor. Group 4 lacks both graphene oxide and nano-copper-zinc oxide, has a bacteriostatic rate of less than 60% on staphylococcus aureus, escherichia coli and candida albicans, and has poor antibacterial property. The wig fibers of the group 1 added with the antibacterial agent in a reasonable ratio have the bacteriostasis rate higher than 95% on staphylococcus aureus, escherichia coli and candida albicans, and show excellent antibacterial performance.

TABLE 3 antibacterial Property test of wig fibers prepared from each group

Test example 3

Core flame retardancy test

In order to further illustrate the core layer flame retardant performance of the sheath-core polyester-nylon composite wig fiber, a Limiting Oxygen Index (LOI) test and a vertical burning test (UL 94) are carried out.

Limiting oxygen index test (LOI): the oxygen index test is carried out according to the national standard GB/T5454-1997.

Vertical burning test (UL 94): the vertical burn test was determined according to GB/T5455-2004. The test grades are HB, V-2, V-1 and V-0.

The test was divided into 4 groups, with groups 1 and 4 having the complete composite fiber core component of the invention, group 2 lacking the intumescent graphite flame retardant component, group 3 lacking the CEPPA component, and the raw materials and parts of each group are shown in Table 4. Groups 1-3 the modified flame retardant PET was prepared as described in example 6, group 4 the modified flame retardant PET was prepared by a method different from group 1 by directly melt blending PET, CEPPA, and the expandable graphite flame retardant in an open mill at 190 ℃ for 30min. The remaining preparation steps, groups 1-4, were identical.

TABLE 4 raw materials and parts of wig fibers of each group

Weighing the modified flame-retardant PET, the calcium carbonate and the ethylene bis-stearamide according to the parts by weight in the table 1, crushing raw materials, granulating, extruding, heat setting, collecting filaments and packaging to obtain the four groups of wig fibers.

The flame retardant properties of the 4 samples are shown in table 5. The PET itself is a flammable material, so the test does not carry out the flame retardant performance test on the PET without any flame retardant component. Group 1, namely the wig fiber of the invention, the limiting oxygen index can reach 35%, the limit oxygen index can reach V-0 grade under UL 94 vertical burning test method, the wig fiber belongs to a flame-retardant material, and no drop is generated in the test process, which shows that the wig fiber of the invention has excellent flame retardant property. The groups 2 and 3 lack intumescent graphite flame retardant or CEPPA components respectively, the limiting oxygen indexes are 30 percent and 29 percent respectively, and UL 94 vertical burning tests show that the V-1 grade shows that the flame retardant performance is obviously reduced in the absence of any component of the flame retardant. Although the group 4 has complete components of the composite fiber core layer of the invention, when the modified flame-retardant PET is prepared, the PET, the CEPPA and the expandable graphite flame retardant are directly subjected to melt blending, compared with the in-situ addition of the CEPPA in the group 1, the limiting oxygen index of the group 4 is reduced to 32%, the UL 94 vertical combustion test shows that the limiting oxygen index is V-1 grade, and the in-situ addition of the CEPPA plays an important role in the flame retardance of the modified flame-retardant PET of the invention.

TABLE 5 flame retardancy Properties of the respective groups of samples

Group of	LOI(％)	UL 94
			Group 1	35	V-0
Group 2	30	V-1
			Group 3	29	V-1
Group 4	32	V-1

Test example 4

Inventive examples 1-6 compare performance to commercially available wigs

To further compare the antibacterial and flame retardant properties of the composite wig fibers of the present invention with commercially available wigs, the following tests were performed. As can be seen from Table 6, the bacteriostatic rates of the inventive examples 1-6 on Staphylococcus aureus, escherichia coli and Candida albicans are all higher than 97%, the limiting oxygen index is higher than 34%, and the inventive examples 1-6 reach V-0 level under the UL 94 vertical combustion test method, which indicates that the inventive examples 1-6 are all flame retardant materials and have excellent bacteriostatic performance. The three commercially available wig fibers have significantly lower bacteriostatic rates on staphylococcus aureus, escherichia coli and candida albicans than those of the three commercially available wig fibers of examples 1-6 of the invention. The limited oxygen index for the rebaka and eremei hairpieces was 30% and the UL 94 vertical burn test showed a V-1 rating. The limiting oxygen index of the Edland silk hairpiece was 27%, and the UL 94 vertical burn test showed that there was flaming drips, which was a V-2 rating. The above tests show that the composite wig fibers prepared in examples 1-6 according to the present invention have superior antibacterial and flame retardant properties compared to commercially available wigs.

TABLE 6 antibacterial and flame retardant Properties of wig samples of each group

The test examples show that the wig fiber prepared by the invention has excellent antibacterial and flame retardant properties, is harmless to people and has no health and safety hazard in use.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber is characterized by comprising the following components in parts by weight: 50-100 parts of modified antibacterial PA, 200-300 parts of PA, 20-40 parts of modified flame-retardant PET, 90-150 parts of PET, 1-5 parts of thermochromic microcapsule toner, 2-5 parts of auxiliary additive and 2-8 parts of dispersant.

2. The antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber as claimed in claim 1, wherein the modified antibacterial PA is prepared from the following components in a molar ratio of (100-140): (3-18): and (1-3) PA, nano copper-zinc oxide and graphene oxide.

3. The antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber as claimed in claim 1, wherein the modified antibacterial PA is prepared from the following components in a molar ratio of (110-130): (8-18): and (2-3) PA, nano copper-zinc oxide and graphene oxide.

4. The antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber according to claim 1, wherein the modified flame-retardant PET is prepared from the following raw materials in a molar ratio of (80-120): (2-5): (6-15) PET, 2-carboxyethylphenylphosphinic acid (CEPPA) and an expandable graphite flame retardant.

5. The antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber according to claim 1, wherein the modified flame-retardant PET is prepared from the following raw materials in a molar ratio of (90-120): (3-5): (8-13) PET, CEPPA, expandable graphite flame retardant.

6. The antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber as claimed in claim 1, wherein the thermochromic microcapsule toner is prepared from the following components in a molar ratio of (2-12): (3-15): (5-18) urea-formaldehyde resin, bisphenol A, 2-phenylamino-3-methyl-6-dibutylfluorane.

7. The antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber according to claim 1, wherein the auxiliary additive is one or more of calcium carbonate, mica powder, silica, talcum powder, silica micropowder, titanium dioxide and glass beads; the dispersant is one of ethylene bisstearamide and barium stearate.

8. The preparation method of the antibacterial flame-retardant sheath-core polyester-nylon composite wig fiber according to claim 1, characterized by comprising the following steps:

(1) Preparing modified antibacterial PA: mixing the components in a molar ratio of (100-140): (3-18): and (1) carrying out melt blending on the PA, the nano copper-zinc oxide and the graphene oxide in an open mill under the following conditions: the temperature is 170 ℃, and the time is 40min;

(2) Preparing a skin layer spinning solution: the weight portion ratio is (50-100): (200-300): (1-5): (1-3): (1-5) uniformly mixing the modified antibacterial PA and PA, the thermochromic microcapsule toner, the auxiliary additive and the dispersing agent;

(3) Preparing modified flame-retardant PET: preparing a molar ratio of (80-120): (2-5): (6-15) PET, CEPPA and expandable graphite flame retardant, copolymerizing the PET and the CEPPA, and melt-blending the copolymerized product and the expandable graphite flame retardant in an open mill under the following conditions: the temperature is 190 ℃, and the time is 30min;

(4) Preparing a core layer spinning solution: mixing the components in a molar ratio of (20-40): (90-150): (1-2): (1-3) uniformly mixing the modified flame-retardant PET, the auxiliary additive and the dispersing agent;

(5) Sheath-core composite spinning: spinning and forming the skin layer spinning solution and the core layer spinning solution in a skin-core bi-component spinning component with the coagulation bath temperature of 4 ℃ to obtain gel fiber;

(6) Carrying out wet-heat stretching and water washing on the gel fiber obtained in the step (5), wherein the total stretching multiple is 12-14 times, and the temperature is 50-90 ℃;

(7) Carrying out dry heat stretching on the gel fiber obtained in the step (6), wherein the temperature is 150-170 ℃, and the stretching ratio is 2;

(8) And (4) performing thermal relaxation treatment on the gel fiber obtained in the step (7), wherein the temperature is 220 ℃, and the relaxation rate is 50%.