阅读说明：本技术 一种可降解熔纺聚氨酯弹性纤维 (Degradable melt-spun polyurethane elastic fiber ) 是由 邵晓林 温作杨 杨晓印 陈敏 陈厚翔 许图远 张经翰 钟姜莱 于 2021-10-14 设计创作，主要内容包括：本发明是一种可降解熔纺聚氨酯弹性纤维,该可降解熔纺聚氨酯弹性纤维含有聚氨酯和交联剂,聚氨酯与交联剂的质量比为19:1～3:1；其中,所述交联剂采用二异氰酸酯与共聚多元醇反应获得；所述的共聚多元醇为环氧化合物与羟基官能度为3以上的多元醇聚合得到,分子量为500～2500,所述的环氧化合物为环氧乙烷、环氧丙烷、环氧丁烷、环氧戊烷、环氧己烷或其异构体中的一种及以上。该弹性纤维具有无毒性、力学性能适宜、加工性能及可降解性优异,能满足包括口罩在内的医疗材料的应用。(The invention relates to a degradable melt-spun polyurethane elastic fiber, which contains polyurethane and a crosslinking agent, wherein the mass ratio of the polyurethane to the crosslinking agent is 19: 1-3: 1; wherein the cross-linking agent is obtained by reacting diisocyanate with copolyol; the copolymerized polyol is obtained by polymerizing an epoxy compound and polyol with the hydroxyl functionality of more than 3, the molecular weight is 500-2500, and the epoxy compound is one or more of ethylene oxide, propylene oxide, butylene oxide, cyclopentane oxide, and hexane oxide or isomers thereof. The elastic fiber has the advantages of no toxicity, proper mechanical property, excellent processability and degradability, and can meet the application requirements of medical materials including masks.)

1. The degradable melt-spun polyurethane elastic fiber is characterized by comprising polyurethane and a cross-linking agent, wherein the mass ratio of the polyurethane to the cross-linking agent is 19: 1-3: 1; wherein the cross-linking agent is obtained by reacting diisocyanate with copolyol.

2. The degradable melt-spun polyurethane elastic fiber according to claim 1, wherein the copolymerized polyol is obtained by polymerizing an epoxy compound and a polyol having a hydroxyl functionality of 3 or more, and has a molecular weight of 500 to 2500.

3. The degradable melt-spun polyurethane elastic fiber of claim 2, wherein the epoxy compound is one or more of ethylene oxide, propylene oxide, butylene oxide, pentylene oxide, hexylene oxide or isomers thereof.

4. The degradable melt-spun polyurethane elastic fiber of claim 2, wherein the polyol having a hydroxyl functionality of 3 or more is one or more of xylitol, sorbitol, mannitol, methyl glucoside, soybean oil polyol, palm oil polyol, or rosin ester polyol.

5. The degradable melt-spun polyurethane elastic fiber of claim 1, wherein the diisocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, or isomers thereof.

6. The degradable melt-spun polyurethane elastic fiber according to claim 1, wherein the NCO mass fraction of the crosslinking agent is 3-8%.

7. The degradable melt-spun polyurethane elastic fiber of claim 1, wherein the polyurethane is obtained by reacting diisocyanate, a chain extender and a polymer diol.

8. The degradable melt-spun polyurethane elastic fiber of claim 7, wherein the chain extender is a C2-C10 diol; or a mixture of C4-C12 dihydric alcohol containing carboxylic acid groups and C2-C10 dihydric alcohol, wherein the molar content of the C2-C10 dihydric alcohol in the total chain extender is 80-100%, and the molar content of the C4-C12 dihydric alcohol containing carboxylic acid groups in the total chain extender is less than or equal to 20%.

9. The degradable melt-spun polyurethane elastic fiber of claim 7, wherein the C2-C10 diol is one or more of ethylene glycol, propylene glycol, butanediol or hexanediol; the C4-C12 dihydric alcohol of the carboxylic acid group is one or more of dimethylolpropionic acid or dimethylolbutyric acid.

10. The degradable melt-spun polyurethane elastic fiber of claim 7, wherein the polymer diol is one or more of polyether ester diol, polyether diol or polyester diol, and the molecular weight is 3000-8000; wherein the polyether ester dihydric alcohol is one or more of polytetrahydrofuran-caprolactone diol and polytetrahydrofuran-polycarbonate diol; the polyester diol is one or more of polycaprolactone diol and polycarbonate diol; the polyether diol is one or more of polytetrahydrofuran diol, polytrimethylene ether diol, polyoxyethylene diol or polyoxypropylene diol.

Technical Field

The invention relates to a fusible polyurethane elastic fiber, a preparation method of the polyurethane elastic fiber capable of being melt spun, and application of the polyurethane elastic fiber capable of being melt spun; belongs to the technical field of preparation of polyurethane elastic fiber capable of melt spinning.

Background

The medical mask comprises a mask body and a tightening belt, wherein the mask body is divided into an inner layer, a middle layer and an outer layer, the inner layer is made of a skin-friendly material, the middle layer is an isolation filter layer, and the outer layer is an antibacterial layer made of a special material. The tensioning belt is generally formed by interweaving spandex and terylene and has the function of enabling the protective cover to be tightly attached to the face of a person and ensuring that outside air enters the mouth and the nose after being filtered by the protective layer. The mask belt is not only the key point of the protective effect of the protective cover, but also directly determines the wearing comfort of the mask. The main raw material for making the mask belt capable of making size expansion and contraction regulation according to different human face width is fibre-polyurethane elastic fibre. Therefore, the quality of the polyurethane elastic fiber directly affects the quality of the mask. Meanwhile, spandex is difficult to degrade in nature and recycle, and a series of problems are brought to the environment.

Because the polyurethane elastic fiber is used for the ear belt, the using amount of the polyurethane elastic fiber is small, and related enterprises and research institutions have few researches on the technology of using spandex for the ear belt, which is only reported. Generally, most manufacturers adopt a dry spandex process, and the thick denier composite yarn is 70-140 denier. Chinese patent CN111424332A entitled Spandex for mask belt and preparation method thereof introduces a Spandex product with high elongation, good resilience, high elasticity retention rate and rapid hot melt solidification property obtained by dry production process. The processing performance and the use comfort of the spandex are improved. As a product to be applied in the medical field, the mask elastic ear band should not use high-toxicity, carcinogenic or potential carcinogenic substances and known materials which can cause skin irritation or other adverse reactions, and the residual quantity of other substances for limiting use should meet the relevant requirements without peculiar smell. It is known that dry-process spandex, because of the solvent content of the process, also contains small amounts of low-toxicity, pungent-odor DMAc or DMF solvents, which are essentially unavoidable and may pose a little potential risk.

Generally, polyurethane elastic fiber for ear band of medical mask mainly has the following 3 requirements: (1) green and low toxicity: the skin-friendly contact is realized, and no adverse reaction is caused; (2) suitable mechanical properties are: the ear pad has high elongation, low modulus and easy stretching, is comfortable when being worn on ears and cannot be tightened too tightly; (3) excellent processability: when the spandex is fixed to the mask by ultrasonic welding or hot pressing, the spandex can be easily melted and solidified.

Compared with the polyurethane elastic fiber prepared by the conventional dry spinning method, the polyurethane elastic fiber for the degradable ear band is produced by adopting the melt spinning manufacturing process, and the product is the best choice of medical equipment because the polyurethane elastic fiber does not contain organic solvents and is green and environment-friendly. However, the mechanical property and the physical and chemical resistance of the fiber are still insufficient compared with those of the dry spinning technology. For example: chinese patent CN08705A "a method for producing polyurethane elastic fiber" teaches about the method for preparing polyurethane elastic fiber by melt method, but because the fiber prepared by melt method has certain defects in mechanical properties and uniformity compared with dry method, it is difficult to popularize. Chinese patent CN104593883A "a method for preparing a high-resilience low-drafting differential melt-spun spandex filament" prepares a fiber with the advantages of environmental protection, high strength, high elastic recovery, good high-temperature resistance, easy unwinding and the like by improving the proportion of cross-linking agent components and the coiling recovery rate, but the elongation at break is lower, so that the method is suitable for low-drafting and is not suitable for the process under a larger drafting multiple.

Disclosure of Invention

The technical problem is as follows: the invention aims to provide a degradable melt-spun polyurethane elastic fiber which has the advantages of no toxicity, proper mechanical property, excellent processability and degradability and can meet the application of medical materials including masks.

The technical scheme is as follows: the degradable melt-spun polyurethane elastic fiber contains polyurethane and a cross-linking agent, wherein the mass ratio of the polyurethane to the cross-linking agent is 19: 1-3: 1; wherein the cross-linking agent is obtained by reacting diisocyanate with copolyol.

Wherein the content of the first and second substances,

the copolymerized polyol is obtained by polymerizing an epoxy compound and a polyol with the hydroxyl functionality of more than 3, and the molecular weight is 500-2500.

The epoxy compound is one or more of ethylene oxide, propylene oxide, butylene oxide, cyclopentane oxide, and hexane oxide or isomers thereof.

The polyol with the hydroxyl functionality of more than 3 is one or more of xylitol, sorbitol, mannitol, methyl glucoside, soybean oil polyol, palm oil polyol or rosin ester polyol.

The diisocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate or isomers thereof.

The mass fraction of NCO in the crosslinking agent is 3-8%.

The polyurethane is obtained by reacting diisocyanate, a chain extender and polymer diol.

The chain extender is C2-C10 dihydric alcohol; or a mixture of C4-C12 dihydric alcohol containing carboxylic acid groups and C2-C10 dihydric alcohol, wherein the molar content of the C2-C10 dihydric alcohol in the total chain extender is 80-100%, and the molar content of the C4-C12 dihydric alcohol containing carboxylic acid groups in the total chain extender is less than or equal to 20%.

The dihydric alcohol of C2-C10 is one or more of ethylene glycol, propylene glycol, butanediol or hexanediol; the C4-C12 dihydric alcohol of the carboxylic acid group is one or more of dimethylolpropionic acid or dimethylolbutyric acid.

The polymer dihydric alcohol is one or more of polyether ester dihydric alcohol, polyether dihydric alcohol or polyester dihydric alcohol, and the molecular weight is 3000-8000; wherein the polyether ester dihydric alcohol is one or more of polytetrahydrofuran-caprolactone diol and polytetrahydrofuran-polycarbonate diol; the polyester diol is one or more of polycaprolactone diol and polycarbonate diol; the polyether diol is one or more of polytetrahydrofuran diol, polytrimethylene ether diol, polyoxyethylene diol or polyoxypropylene diol.

Has the advantages that: the melt-spun polyurethane elastic fiber disclosed by the invention is used for carrying out molecular design and modification on polyurethane, and introducing a polyether/polyester chain segment with high molecular weight, so that the structure of a soft segment is optimized, the proportion of the soft segment is improved, the mechanical property of the polyurethane elastic fiber is improved, the elongation is increased, and the modulus is reduced; the special cross-linking agent is adopted to be cooperated with polyurethane, so that the processing type of the polyurethane elastic fiber is improved, and the characteristic of degradability of the polyurethane elastic fiber after being discarded is given. The melting method technology is adopted, the adverse effect of a dry production process solvent is avoided, the characteristics of environmental protection, low toxicity and the like are achieved, the product can be safely and stably applied to daily life, and after the product is blended with other fibers and prepared into an ear belt or a textile, the whole comfort is good and the tightness is proper in the wearing and using processes.

Detailed Description

The melt-spun polyurethane elastic fiber contains polyurethane and a crosslinking agent, wherein the mass ratio of the polyurethane to the crosslinking agent is 19: 1-3: 1.

The cross-linking agent is obtained by reacting diisocyanate and copolyol, and the mass fraction of NCO of the chain extender is 3-8%.

The copolymerized polyol is obtained by polymerizing an epoxy compound and polyol with the hydroxyl functionality of more than 3, and the molecular weight is 500-2500;

the epoxy compound comprises one or more of ethylene oxide, propylene oxide, butylene oxide, cyclopentane oxide, hexane oxide and isomers thereof;

the polyol with the hydroxyl functionality of more than 3 is one or more of xylitol, sorbitol, mannitol, methyl glucoside, soybean oil polyol, palm oil polyol and rosin ester polyol;

the diisocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isomers thereof.

The preparation of the copolyol can be realized by blending tetrahydrofuran and polyalcohol, reacting the mixture under the protection of inert gas through a Lewis acid catalyst to obtain the copolyol, and controlling the reaction temperature to be 100-120 ℃;

the preparation of the cross-linking agent can be realized by carrying out melt mixing reaction on the copolyol and diisocyanate under the protection of inert gas to obtain the cross-linking agent, wherein the reaction temperature is controlled at 50-80 ℃;

as an example, the inert gas is nitrogen.

The polyurethane is obtained by reacting diisocyanate, a chain extender and polymer diol;

the chain extender is C2-C10 dihydric alcohol and comprises one or more of ethylene glycol, propylene glycol, butanediol and hexanediol;

the chain extender can also be a mixture of two dihydric alcohols of C2-C10 dihydric alcohol and C4-C12 dihydric alcohol with carboxylic acid groups, wherein the C4-C12 dihydric alcohol with carboxylic acid groups comprises one or more than one of dimethylolpropionic acid and dimethylolbutyric acid; wherein, the mole ratio of the C2-C10 dihydric alcohol in the chain extender is 80-100 percent, and the mole content of the C4-C12 dihydric alcohol containing carboxylic acid groups in the total chain extender is less than or equal to 20 percent;

the polymer dihydric alcohol is one or more of polyether ester dihydric alcohol, polyether dihydric alcohol and polyester dihydric alcohol, and the molecular weight is 3000-8000;

wherein, the polyether ester dihydric alcohol is one or more of polytetrahydrofuran-caprolactone diol and polytetrahydrofuran-polycarbonate diol, the polyester dihydric alcohol is one or more of polycaprolactone diol and polycarbonate diol, and the polyether dihydric alcohol is one or more of polytetrahydrofuran diol, polytrimethylene ether diol, polyoxyethylene diol and polyoxypropylene diol.

The proportion of the diisocyanate, the chain extender and the polymer diol is not specially required, and the proportion can be adjusted according to actual use, so that the molar ratio of the isocyanate groups in the raw material components to the groups with reactivity to the isocyanate groups is 0.95-1.05: 1, the product is obtained.

Further, the polyurethane may contain optionally at least one catalyst, and/or optionally at least one auxiliary;

the catalyst is a catalyst commonly used in the field and comprises one or more of an organic tin catalyst, a potassium carboxylate catalyst, an organic heavy metal catalyst, zinc carboxylate, bismuth carboxylate and a titanate catalyst;

the auxiliary agent is one or more of the auxiliary agents commonly used in the field, such as an antioxidant, an ultraviolet absorber, a hydrolysis resistance agent, a plasticizer, a light stabilizer, a lubricant and an antibacterial agent, and the additives are known by the technical personnel in the field.

The polyurethanes can be prepared by methods known in the art, for example: adding diisocyanate, a chain extender and polymer diol into a screw extruder, and performing melt extrusion to obtain the product by a one-step method; the polyurethane is prepared by reacting diisocyanate with polymer diol to obtain isocyanate prepolymer and reacting with the rest of chain extender in a two-step method, and can be prepared into particles for use.

The preparation method of the fusible polyurethane elastic fiber comprises the following steps: and adding a crosslinking agent into the molten polyurethane, mixing, and extruding the melt through a spinning assembly to obtain the melt-spun polyurethane elastic fiber.

As an example, a melt-spinnable polyurethane elastic fiber is prepared by:

after the polyurethane is melted and fully mixed with the cross-linking agent through a mixer, the mixture passes through a melt metering pump and a distribution plate to a spinneret plate;

the melt is cooled by a spinning box and side-blown air, passes through a spinning channel, is oiled, and is spun into polyurethane elastic fiber capable of being melt-spun.

Wherein the temperature of the spinning box is controlled to be 180-230 ℃, the temperature of the cross air blow is 10-25 ℃, and the spinning speed is 500-900 m/min.

As an example, the melt-spinnable polyurethane elastic fiber has a denier per filament of 70D or more.

The polyurethane elastic fiber capable of being melt spun can be blended with polyester fiber to be used as an ear belt of a mask, and can also be blended with other fibers to be applied to the textile field.

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.

(1) Preparing polyurethane:

polyurethane 1: adding 10.0mol of polytetrahydrofuran diol PTMG20.0mol of di-4, 4 '-phenylmethane diisocyanate 4, 4' -MDI, 8.0mol of 1, 4-butanediol and 2.0mol of dimethylolbutyric acid with the molecular weight of 3000 into a double-screw reactor for melt extrusion, carrying out underwater granulation to obtain polyurethane particles, and carrying out vacuum drying at 105 ℃ until the moisture content is below 30ppm for later use.

Polyurethane 2: adding 10.0mol of polytetrahydrofuran diol PTMG20.0mol of 4,4 '-phenylmethane diisocyanate 4, 4' -MDI, 8.0mol of 1, 4-butanediol and 2.0mol of dimethylolpropionic acid with the molecular weight of 3000 into a double-screw reactor for melting, mixing and slicing to obtain polyurethane slices, cleaning the polyurethane slices by deionized water, carrying out vacuum drying at 105 ℃ for 180min, carrying out underwater dicing to obtain polyurethane particles, and carrying out vacuum drying at 105 ℃ until the water content is below 30ppm for later use.

Polyurethane 3: adding 5.0mol of polytetrahydrofuran diol PTMG with the molecular weight of 3000, 5.0mol of polycaprolactone diol PCL with the molecular weight of 3000, 20.0mol of 4,4 '-phenyl methane diisocyanate 4, 4' -MDI, 8.0mol of 1, 4-butanediol and 2.00mol of dimethylolbutyric acid into a double-screw reactor for melting, mixing and slicing to obtain polyurethane slices, cleaning by deionized water, and carrying out vacuum drying at 105 ℃ for 180min, wherein the vacuum degree is-0.08 MPa, and the water content is below 30ppm for later use.

Polyurethane 4: adding 10.0mol of polycaprolactone diol PCL with the molecular weight of 5000, 20.0mol of 4,4 '-phenyl methane diisocyanate 4, 4' -MDI, 8.0mol of 1, 6-hexanediol and 2.00mol of dimethylolbutyric acid into a double-screw reactor for melting, mixing and slicing to obtain polyurethane slices, cleaning by deionized water, and performing vacuum drying at 105 ℃ for 180min, wherein the vacuum degree is-0.08 MPa, and the water content is below 30ppm for later use.

Polyurethane 5: adding 10.0mol of polytetrahydrofuran diol PTMG20.0mol of 4,4 '-phenylmethane diisocyanate 4, 4' -MDI with the molecular weight of 3000 and 10mol of 1, 4-butanediol into a double-screw reactor for melting, mixing and slicing to obtain polyurethane slices, washing by deionized water, carrying out vacuum drying for 180min at 105 ℃, carrying out underwater dicing to obtain polyurethane particles, and carrying out vacuum drying at 105 ℃ until the moisture is below 30ppm for later use.

Polyurethane 6: adding 10.0mol of polytetrahydrofuran diol PTMG with the molecular weight of 3000, 20.0mol of 4,4 '-phenylmethane diisocyanate 4, 4' -MDI and 10mol of dimethylolbutyric acid into a double-screw reactor for melting, mixing and slicing to obtain polyurethane slices, washing by deionized water, carrying out vacuum drying for 180min at 105 ℃, carrying out underwater cutting to obtain polyurethane particles, and carrying out vacuum drying at 105 ℃ until the moisture is below 30ppm for later use.

(2) Preparing a cross-linking agent:

crosslinking agent 1: under the protection of nitrogen, 10.0mol of PTMG (molecular weight is 250) and 14.0mol of 4,4 '-phenyl methane diisocyanate 4, 4' -MDI are mixed and reacted to generate a cross-linking agent with NCO end group mass fraction of 5.6%, and the cross-linking agent is sealed and stored for standby.

Crosslinking agent 2: under the protection of nitrogen, 10.0mol of sorbitol and 14.0mol of 4,4 '-phenyl methane diisocyanate 4, 4' -MDI are mixed and reacted to generate a cross-linking agent with the NCO end group mass fraction of 5.6%, and the cross-linking agent is sealed and stored for standby.

Crosslinking agent 3: under the protection of nitrogen, blending 12.0mol of tetrahydrofuran and 2.0mol of sorbitol, adding 1% of Lewis acid catalyst, and reacting at 115 ℃ for 3 hours to obtain copolyol with the molecular weight of 500;

under the protection of nitrogen, 10.0mol of copolyol and 16.0mol of 4,4 '-phenylmethane diisocyanate 4, 4' -MDI are mixed and reacted at 60 ℃ to generate a cross-linking agent with NCO end group mass fraction of 5.6%, and the cross-linking agent is sealed and stored for standby.

Crosslinking agent 4: under the protection of nitrogen, 15.0mol of ethylene oxide and 3.0mol of mannitol are blended, 1% of Lewis acid catalyst is added, and the mixture reacts for 4 hours at 100 ℃ to obtain the copolyol with the molecular weight of 1500;

under the protection of nitrogen, 10.0mol of copolyol and 24.0mol of 4,4 '-phenyl methane diisocyanate 4, 4' -MDI are mixed and reacted at 60 ℃ to generate a cross-linking agent containing 5.6% of NCO end group mass fraction, and the cross-linking agent is sealed and stored for standby.

Crosslinking agent 5: under the protection of nitrogen, 15.0mol of propylene oxide and 5.0mol of xylitol are blended, 1% of Lewis acid catalyst is added, and the mixture reacts for 4 hours at 105 ℃ to obtain the copolyol with the molecular weight of 1000;

under the protection of nitrogen, 10.0mol of copolyol and 23.15mol of 4,4 '-phenyl methane diisocyanate 4, 4' -MDI are mixed and reacted at 60 ℃ to generate a cross-linking agent with NCO end group mass fraction of 7%, and the cross-linking agent is sealed and stored for standby.

Wherein, the Lewis acid catalyst in the preparation of the cross-linking agent is one or more of aluminum chloride, ferric bromide and boron trifluoride, and the preparation example of the cross-linking agent adopts acid aluminum chloride.

Comparative example 1

10.00mol of polytetrahydrofuran diol PTMG with molecular weight of 3000 and 17.50mol of 4,4 ' -phenylmethane diisocyanate 4,4 ' -MDI are subjected to prepolymerization reaction to obtain prepolymer PP, the prepolymer PP is dissolved into prepolymer solution PPS by N, N ' -dimethylacetamide DMAC, 2.50mol of ethylenediamine and 0.50mol of diethylamine mixed amine (DMAC solution with concentration of 5%) are added at low temperature, the mixture is fully stirred and reacted to obtain polyurethane spinning stock solution with concentration of 35%, and after curing, dry spinning is carried out to obtain dry spinning comparative sample 1.

Comparative example 2

Melting polyurethane 1, and then distributing the molten polyurethane to a component spinneret plate through a melt metering pump and a distribution plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun comparative sample 2.

Comparative example 3

Melting polyurethane 1, and then mixing the melted polyurethane with a cross-linking agent 3 in a mass ratio of 20: 1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun comparative sample 3.

Comparative example 4

Melting polyurethane 1, and then mixing the melted polyurethane with a cross-linking agent 3 in a mass ratio of 2: 1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun comparative sample 4.

The degradable melt-spun polyurethane elastic fiber contains polyurethane and a cross-linking agent, wherein the mass ratio of the polyurethane to the cross-linking agent is 19: 1-3: 1; wherein the cross-linking agent is obtained by reacting diisocyanate with copolyol.

Example 1

Melting polyurethane 1, and then mixing the melted polyurethane with a cross-linking agent 3 in a mass ratio of 9:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun sample 1.

Example 2

Melting polyurethane 2, and then mixing the melted polyurethane with a cross-linking agent 3 in a mass ratio of 9:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun sample 2.

Example 3

Melting polyurethane 3, and then mixing the melted polyurethane 3 with a cross-linking agent 3 in a mass ratio of 9:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun sample 3.

Example 4

Melting polyurethane 3, and then mixing the melted polyurethane with a cross-linking agent 4 in a mass ratio of 19:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun sample 4.

Example 5

Melting polyurethane 3, and then mixing the melted polyurethane 3 with a cross-linking agent 5 in a mass ratio of 3:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun sample 5.

Example 6

Melting polyurethane 1, and mixing the melted polyurethane 1 with a cross-linking agent 1 in a mass ratio of 9:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun comparative sample 6.

Example 7

Melting polyurethane 1, and then mixing the melted polyurethane with a cross-linking agent 2 in a mass ratio of 9:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate;

the melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun comparative sample 7.

Example 8

Melting polyurethane 5, and then mixing the melted polyurethane with a cross-linking agent 4 in a mass ratio of 19:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate; the chain extender is pure BDO.

The melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun sample 8.

Example 9

Melting polyurethane 6, and then mixing the melted polyurethane with a cross-linking agent 4 in a mass ratio of 19:1, after fully mixing in a static mixer, passing through a solution metering pump and a distribution plate to a component spinneret plate; the chain extender is pure dimethylolbutyric acid.

The melt was cooled by a spinning box (temperature 200 ℃), side-blown (cooling air temperature 20 ℃, cooling blowing speed 0.4m/min), spinning channel, oiling agent (oiling rate 4%), and wound to form a monofilament 70D melt-spun sample 9.

The results of the performance testing of each sample are shown in the following table (taking 70D (1H) as an example):

the method for testing 300% stress at definite elongation and elongation at break comprises the following steps: the sample was pulled apart by a constant-speed elongation type tensile machine under constant-temperature and constant-humidity conditions of 20 ℃. + -. 1 ℃ and a humidity of 65%. + -. 5% at a predetermined initial length, pretension and stretching speed, and the elongation stress at 300% and elongation at break were recorded.

Rebound resilience: under the conditions of constant temperature and constant humidity of the sample at the temperature of 20 +/-1 ℃ and the humidity of 65 +/-5 percent, a constant-speed elongation strengthening machine is used for carrying out stretching recovery circulation between 0 percent and 300 percent of elongation, and then the 300 percent of elastic recovery rate is calculated according to the variation of corresponding indexes before and after the stretching after the time delay of a specified time.

Processability: including melt spinning processes and fiber post-processability. And secondly, when the fiber is fixed on the mask through ultrasonic welding or hot pressing, the melting and curing effects of the product and the bonding effect of the product and the mask are evaluated from good to bad in four grades, namely good, common and bad.

The degradability is as follows: according to the GB/T19277 detection method, sample materials and compost inoculum are mixed and then put into a composting container, the composting is carried out fully under the conditions of certain oxygen, temperature (58 +/-2C) and humidity (50-55%), the final release amount of CO2 (which can be prolonged to 6 months) is measured after the materials are degraded for 45 days, and the biodegradation rate of the materials is expressed by the ratio of the actual CO2 release amount to the theoretical maximum release amount.

As can be seen from the above table, the 300% stress at elongation at break of samples 1-9 is maintained in the appropriate range of 13-14.2cN/D, the elongation at break is maintained at about 600%, the manufactured earband feels comfortable when worn on the ear, and the fiber has high processability and degradability. Comparative sample 1 (a conventional 70D-sized polyurethane elastic fiber produced by a dry process technique on the market) has better resilience, but the 300% stress at definite elongation (modulus) is significantly higher and the elongation is lower than those of samples 1 to 9, and the comfort when the ear band is worn on the ear is poor, and the degradable effect of comparative sample 1 is inferior to that of samples 1 to 9. Compared with the comparative sample 1, the comparative sample 2 has no crosslinking agent, the resilience and biodegradability of the fiber are obviously poor, and the processability is not good. Compared with sample 1, the addition amount of the cross-linking agent of the comparative samples 3 and 4 is too small, the rebound resilience and the biodegradability of the comparative sample 3 are obviously poor, and the processability is not good; comparative sample 4 had too much crosslinking agent added to make melt spinning impossible.

After a cross-linking agent is added into the molten polyurethane and mixed, the melt is extruded by a spinning assembly to obtain melt-spun polyurethane elastic fiber, which can be blended with polyester fiber to be used as an ear belt of a mask and can also be blended with other fibers to be applied to the textile field.

The above description is only exemplary of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.