Hydrophilic spandex fiber and preparation method thereof

Abstract

The invention relates to a hydrophilic polyurethane fiber and a preparation method thereof, the polyurethane fiber contains polyurethane urea A and polyurethane urea B, the polyurethane urea A is obtained by reaction of polyether polyol a, polyisocyanate and mixed amine, and the polyurethane urea B is obtained by reaction of polyether polyol b, polyisocyanate and mixed amine; wherein the polyether polyol a comprises polytetrahydrofuran ether glycol, and the polyether polyol b comprises polyethylene glycol; the mass ratio of the polyurethane urea A to the polyurethane urea B is (73: 27)-(40: 60); the mixed solution of the polyurethane urea A solution and the polyurethane urea B solution serves as a spinning raw material, the hydrophilic spandex fiber is obtained through dry spinning, the problem that oily oil removal of the spandex fiber is difficult is solved, the compatibility of the spandex fiber and a hydrophilic oil agent is good, the adhesiveness of a water-based oil agent on the surface of the fiber is good, and good unwinding performance is achieved.

Description

Technical Field

[0001] The present invention relates to a hydrophilic spandex fiber and a preparation method thereof, belonging to the field of polyurethane-urea elastic fibers. Background Art

[0002] Spandex fibers have special properties such as high breaking elongation rate and high elastic recovery rate, so they are widely used in elastic fabrics and extended to fields such as medical and sports. There are many hydrophobic groups in the spandex molecule, such as methylene chains and aryl groups, and the content of hydrophilic groups is small, belonging to hydrophobic fibers. When spandex fibers are produced, they will go through an oiling process to make them have better unwinding properties for subsequent processing. Due to the hydrophobic and lipophilic characteristics of spandex, its oil absorption is stronger than that of other fibers. Therefore, spandex textiles need to go through a degreasing process. There are many types of spandex oil agents, mainly including: oily oil agents. Since these oil agents have good compatibility with spandex, it is difficult to remove them during the subsequent degreasing process, and the residual oil agents will cause problems such as uneven dyeing; water-based oil agents. Since these oil agents have poor compatibility with spandex, their adhesion on the surface of spandex is poor, resulting in poor unwinding properties of the fibers.

[0003] Currently, the oil agent residue of spandex is reduced by improving the spandex oil agent. For example, CN106283621A discloses a silicone-free oil agent composition for dry spinning of spandex and a preparation method thereof. This method prepares a silicone-free oil agent composition, which at least includes the following components: hydrocarbon compounds, isomeric fatty alcohols or acids, higher fatty acid salts, antistatic agents, and dispersants; this silicone-free oil agent composition overcomes the adverse effects brought by silicone oil in the spandex oil agent and solves the problem of poor dispersibility of stearate salts. However, this oil agent is essentially an oily lubricant and is not easy to completely remove during the pretreatment of textiles. A large amount of water and cleaning agents are still required, which is likely to cause water pollution. However, there are few reports on increasing the hydrophilicity of spandex and cooperating with water-based oil agents to improve its unwinding properties and oil content. Summary of the Invention

[0004] Technical Problem: The purpose of the present invention is to provide a hydrophilic spandex fiber and a preparation method thereof, to solve the problem of difficult oil removal of oily spandex fibers. This spandex fiber has good compatibility with hydrophilic oil agents, good adhesion of water-based oil agents on the fiber surface, and has good unwinding properties.

[0005] Technical Solution: The present invention provides a hydrophilic spandex fiber, which contains polyurethane-urea A and polyurethane-urea B. The polyurethane-urea A is obtained by reacting polyether polyol a, polyisocyanate, and mixed amine, and the polyurethane-urea B is obtained by reacting polyether polyol b, polyisocyanate, and mixed amine;

[0006] Among them, the polyether polyol a includes polytetrahydrofuran ether diol, and the polyether polyol b includes polyethylene glycol;

[0007] The number-average molecular weight of the polyurethane urea A or polyurethane urea B is 40,000 to 70,000 respectively, and the difference in molecular weight between polyurethane urea A and polyurethane urea B is not more than 5,000; the mass ratio of polyurethane urea A to polyurethane urea B is 73:27 to 40:60; preferably 60:40 to 50:50;

[0008] The polyether polyol a includes polytetrahydrofuran ether diol with a number-average molecular weight of 1,000 to 3,000, preferably 1,500 to 2,500; the polyether polyol b includes polyethylene glycol with a number-average molecular weight of 400 to 2,000, preferably 800 to 1,500;

[0009] The polyisocyanate includes one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and / or derivatives and / or modified polymers.

[0010] The mixed amine includes small molecule monoamines and small molecule diamines; the small molecule monoamines include one or more of ethylamine, n-propylamine, isopropylamine, n-butylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, di-n-butylamine, cyclohexylamine; the small molecule diamines include one or more of ethylenediamine, propylenediamine, 2-methyl-1,5-pentanediamine, cyclohexanediamine, trimethylhexamethylenediamine.

[0011] The hydrophilic polyurethane fiber further includes a cellulose organic acid ester alkali-resistant aid, including one or a mixture of cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, cellulose acetate succinate; the addition mass of the alkali-resistant aid is calculated based on the mass of the polyurethane fiber and is 0.5 to 1.5%.

[0012] A preparation method of the hydrophilic polyurethane fiber of the present invention includes using a mixed spinning dope containing polyurethane urea A and polyurethane urea B as a spinning raw material and obtaining it by dry spinning;

[0013] Preferably, a preparation method of the hydrophilic polyurethane fiber of the present invention includes:

[0014] Preparation of polyurethane urea A: React polyether polyol a and polyisocyanate to obtain a prepolymer, dissolve it in the presence of a solvent to obtain a prepolymer solution a1, and react the prepolymer solution a1 with a mixed amine solution containing small molecule monoamines and small molecule diamines to obtain a polyurethane urea A solution;

[0015] Preparation of the polyurethane urea B: React polyether polyol b and polyisocyanate to obtain a prepolymer, dissolve it in the presence of a solvent to obtain a prepolymer solution b1, and react the prepolymer solution b1 with a mixed amine solution containing small molecule monoamines and small molecule diamines to obtain a polyurethane urea B solution;

[0016] A mixed solution of polyurethane urea A solution and polyurethane urea B solution is used as a spinning raw material to obtain hydrophilic spandex fibers through dry spinning.

[0017] The solvent described above includes one or more of N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethylformamide.

[0018] The NCO mass content of the prepolymer is 2 wt% to 4 wt%; preferably 2.2 wt% to 3.7 wt%.

[0019] The mass concentration of the prepolymer solution is 30 wt% to 60 wt%;

[0020] The molar ratio of NCO in the prepolymer to the reactive groups towards NCO in the mixed amine is 1.01 to 1.10.

[0021] The molar ratio of the small molecule diamine to the small molecule monoamine is 1:1 to 30:1.

[0022] The mass concentration of the mixed amine solution is 3 wt% to 10 wt%.

[0023] Beneficial effects: The spandex of the present invention contains two types of polyurethane ureas A and B with different hydrophilicities in specific types and contents. The hydrophilicity of the fibers obtained by co-blending dry spinning is significantly improved. When used in combination with a water-based oil agent, it is easier to apply the oil, and the water-based oil agent is more likely to adsorb on the surface of the spandex fibers, and can maintain good unwinding performance for a long time. Detailed implementation manners

[0024] The present invention provides a hydrophilic spandex fiber, which contains polyurethane urea A and polyurethane urea B. The polyurethane urea A is obtained by reacting polyether polyol a, polyisocyanate, and mixed amine, and the polyurethane urea B is obtained by reacting polyether polyol b, polyisocyanate, and mixed amine;

[0025] Among them, the polyether polyol a includes polytetrahydrofuran ether diol with a number average molecular weight of 1000 to 3000, preferably 1500 to 2500; the polyether polyol b includes polyethylene glycol with a number average molecular weight of 400 to 2000, preferably 800 to 1500;

[0026] Preferably, the molecular weight of the polyurethane urea A and / or polyurethane urea B is 40000 to 70000, and the difference in molecular weight between polyurethane urea A and polyurethane urea B is not greater than 5000;

[0027] The mass ratio of the polyurethane urea A to the polyurethane urea B is 73:27 to 40:60, preferably 60:40 to 50:50;

[0028] The diisocyanate includes one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and / or derivatives and / or modified polymers;

[0029] The mixed amine includes small molecule monoamines and small molecule diamines; the small molecule monoamines include one or more of ethylamine, n-propylamine, isopropylamine, n-butylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, di-n-butylamine, cyclohexylamine; the small molecule diamines include one or more of ethylenediamine, propylenediamine, 2-methyl-1,5-pentanediamine, cyclohexanediamine, trimethylhexamethylenediamine.

[0030] Furthermore, the hydrophilic polyurethane fiber further includes cellulose organic acid ester alkali-resistant aids, including one or a mixture of cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, cellulose acetate succinate;

[0031] The added mass of the alkali-resistant aid is 0.5 - 1.5%, calculated based on the mass of the polyurethane fiber.

[0032] Furthermore, other common functional aids in the art can be added to the polyurethane fiber as long as the product performance is not deteriorated, such as one or more of antioxidants, anti-yellowing agents, anti-sticking agents, ultraviolet absorbers, light stabilizers, lubricants, delustering agents, dyeing aids, chlorine-resistant aids.

[0033] The preparation method of a hydrophilic polyurethane fiber of the present invention includes using a mixed spinning dope containing polyurethaneurea A and polyurethaneurea B as the spinning raw material and obtaining it by dry spinning;

[0034] Preferably, the present invention provides a preparation method of a hydrophilic polyurethane fiber, including:

[0035] The preparation method of polyurethaneurea A: React the polyether polyol a and polyisocyanate to obtain a prepolymer, dissolve it in the presence of a solvent to obtain a prepolymer solution a1, and react the prepolymer solution a1 with a mixed amine solution containing small molecule monoamines and small molecule diamines to obtain a polyurethaneurea A solution;

[0036] The preparation method of polyurethaneurea B includes: React the polyether polyol b and polyisocyanate to obtain a prepolymer, dissolve it in the presence of a solvent to obtain a prepolymer solution b1, and react the prepolymer solution b1 with a mixed amine solution containing small molecule monoamines and small molecule diamines to obtain a polyurethaneurea B solution.

[0037] Using a mixture including the polyurethaneurea A solution and the polyurethaneurea B solution as the spinning raw material to obtain it by dry spinning.

[0038] The solvents described above include one or more of N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethylformamide;

[0039] The NCO mass content of the prepolymer is 2 wt% to 4 wt%, preferably 2.2 wt% to 3.7 wt%;

[0040] The mass concentration of the prepolymer solution is 30 wt% to 60 wt%;

[0041] The molar ratio of NCO in the prepolymer to the reactive groups towards NCO in the mixed amine is 1.01 to 1.10;

[0042] The molar ratio of the small molecule diamine to the small molecule monoamine is 1:1 to 30:1;

[0043] The mass concentration of the mixed amine solution is 3 wt% to 10 wt%.

[0044] The dry spinning method described above includes the steps of spraying, stretching, drying, false twisting, and winding the mixture containing polyurethane urea A and polyurethane urea B through a spinneret assembly into filaments;

[0045] Preferably, the total mass concentration of the mixture is 30 wt% to 40 wt%;

[0046] Preferably, the mixture is aged before dry spinning;

[0047] Preferably, a water-based oil agent is coated on the fiber surface before the winding into filaments step.

[0048] In some examples of the present invention, the preparation method of the hydrophilic spandex fiber specifically includes:

[0049] The preparation step of polyurethane urea: adding the polyether polyol and polyisocyanate described above into a mixer, fully reacting at 60°C to 80°C to obtain a prepolymer, dissolving in the presence of a solvent to obtain a prepolymer solution, and continuing to react the prepolymer solution with a mixed amine solution containing a small molecule monoamine and a small molecule diamine at 70°C to 90°C to obtain a polyurethane urea solution;

[0050] Prepare the polyurethane urea A solution and the polyurethane urea B solution respectively according to the above preparation method;

[0051] Mix the above polyurethane urea A solution and polyurethane urea B solution to obtain a mixture, age it to obtain a spinning solution, and if an alkali-resistant additive is added, it is preferably added to the mixture.

[0052] Dry spinning process: The fully matured skin layer and core layer spinning dope are fed into the spinneret assembly through a metering pump. The spinning solution undergoes spinning and stretching, high-temperature drying to remove the solvent, oiling with an oil agent, and winding and forming, finally resulting in hydrophilic spandex fibers.

[0053] Among them, the oil agent is an aqueous oil agent, and the aqueous oil agent includes one or more of Stantex PP602, Stantex S6327, PPG-3 octyl ether, aqueous silicone oil, and textile lubricant AD-HEG202.

[0054] The following examples are used to describe the production process of the present invention in detail, but these examples should not be construed as any limitation to the present invention.

[0055] Examples 1-9 of the present invention are shown in the following table:

[0056]

[0057] Example 10

[0058] The difference from Example 1 is that 0.6% of cellulose acetate butyrate is added in the mixed spinning, and the others remain unchanged.

[0059] Example 11

[0060] The difference from Example 1 is that 1.2% of cellulose acetate is added in the mixed spinning, and the others remain unchanged.

[0061] Example 12

[0062] The difference from Example 1 is that 0.6% of silicon dioxide is added in the mixed spinning, and the others remain unchanged.

[0063] Comparative Example 1

[0064] The difference from Example 1 is that polytetrahydrofuran ether diol and polyethylene glycol are directly mixed with polyisocyanate and mixed amine to react to obtain polyurethane urea as the spinning dope, and the others remain unchanged.

[0065] Comparative Example 2

[0066] The difference from Example 1 is that pure polyurethane urea B is used as the spinning dope, and the others remain unchanged.

[0067] Comparative Example 3

[0068] The difference from Example 1 is that pure polyurethane urea A is used as the spinning dope, and the others remain unchanged.

[0069] Application Example

[0070] Spandex fibers 1-12 and comparative spandex fibers 1-3 were obtained by the same dry spinning method for Examples 1-12 and Comparative Examples 1-3 respectively. To more intuitively compare the unwinding effect of spandex fibers, when applying the spinning finish, the same type of aqueous spinning finish Stantex PP602 was used, and the coating rate was 3%.

[0071] The following performance tests were carried out on the spandex fibers:

[0072] (1) Unwinding property test: Using an electronic constant tension transmission system, the draw ratio when the filaments on the spandex cake adhered to each other's surfaces was detected under the specified unwinding state. The initial unwinding property and the unwinding property after aging were tested respectively. The smaller the unwinding property detection data, the better the unwinding property; the aging test method was to place the spandex cake in an electrothermal blast drying oven, adjust the temperature to 60 °C, and dry it at a constant temperature for 72 hours, which is equivalent to placing it in the natural environment for half a year.

[0073] (2) Alkali resistance test: A 20% concentration NaOH solution was prepared. The spandex filaments were wound around an iron frame under no-draft conditions and kept at a constant temperature of 110 °C in the alkali solution for 45 min, and the breaking strength retention rate of the spandex fibers was tested.

[0074] Spandex fibers 1-12 and comparative spandex fibers 1-3 are shown in the following table:

[0075]

[0076]

[0077] Among them,

[0078] During the addition process of silicon dioxide in spandex fiber 12, the addition operability was poor, the dispersion effect of silicon dioxide in the spinning solution was not good, and the spinning was unstable;

[0079] After the comparative spandex fiber 2 was treated with alkali, filament breakage occurred and there were no alkali resistance test data.

Claims

1. A hydrophilic spandex fiber, characterized in that, The spandex fiber contains polyurethane urea A and polyurethane urea B. The polyurethane urea A is obtained by reacting a polyether polyol a, a polyisocyanate, and a mixed amine. The polyurethane urea B is obtained by reacting a polyether polyol b, a polyisocyanate, and a mixed amine; Among them, the polyether polyol a includes polytetrahydrofuran ether diol, and the polyether polyol b includes polyethylene glycol.

2. The hydrophilic spandex fiber according to claim 1, characterized in that, The number average molecular weight of the polyurethane urea A or polyurethane urea B is 40,000 to 70,000 respectively, and the molecular weight difference between the polyurethane urea A and the polyurethane urea B is not more than 5,000; the mass ratio of the polyurethane urea A and the polyurethane urea B is 73:27 to 40:60; preferably 60:40 to 50:50; The polyether polyol a includes polytetrahydrofuran ether diol with a number average molecular weight of 1,000 to 3,000, preferably 1,500 to 2,500; the polyether polyol b includes polyethylene glycol with a number average molecular weight of 400 to 2,000, preferably 800 to 1,500.

3. The hydrophilic spandex fiber according to claim 1, characterized in that, The polyisocyanate includes one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and / or derivatives and / or modified polymers.

4. The hydrophilic spandex fiber according to claim 1, characterized in that, The mixed amine includes small molecule monoamines and small molecule diamines; the small molecule monoamines include one or more of ethylamine, n-propylamine, isopropylamine, n-butylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, di-n-butylamine, cyclohexylamine; the small molecule diamines include one or more of ethylenediamine, propylenediamine, 2-methyl-1,5-pentanediamine, cyclohexanediamine, trimethylhexamethylenediamine.

5. The hydrophilic spandex fiber according to claim 1, 2, 3 or 4, characterized in that, The hydrophilic spandex fiber further includes a cellulose organic acid ester alkali-resistant aid, including one or a mixture of cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, cellulose acetate succinate; the added mass of the alkali-resistant aid is calculated based on the mass of the spandex fiber and is 0.5 to 1.5%.

6. A method for preparing a hydrophilic spandex fiber as claimed in claim 1, characterized in that, The preparation method includes: Preparation of polyurethane urea A: React the polyether polyol a and the polyisocyanate to obtain a prepolymer, dissolve it in the presence of a solvent to obtain a prepolymer solution a1, and react the prepolymer solution a1 with a mixed amine solution containing small molecule monoamines and small molecule diamines to obtain a polyurethane urea A solution; Preparation of the polyurethane urea B: React the polyether polyol b and the polyisocyanate to obtain a prepolymer, dissolve it in the presence of a solvent to obtain a prepolymer solution b1, and react the prepolymer solution b1 with a mixed amine solution containing small molecule monoamines and small molecule diamines to obtain a polyurethane urea B solution; Use the mixed solution of the polyurethane urea A solution and the polyurethane urea B solution as a spinning raw material to obtain hydrophilic spandex fiber by dry spinning.

7. The method for preparing a hydrophilic spandex fiber according to claim 6, characterized in that, The solvent includes one or more of N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethylformamide.

8. The method for preparing a hydrophilic spandex fiber according to claim 6, characterized in that, The NCO mass content of the prepolymer is 2 wt% to 4 wt%; preferably 2.2 wt% to 3.7 wt%; The mass concentration of the prepolymer solution is 30 wt% to 60 wt%; The molar ratio of NCO of the prepolymer to the reactive groups towards NCO in the mixed amine is 1.01 to 1.

10.

9. The method for preparing a hydrophilic spandex fiber according to claim 6, characterized in that, The molar ratio of the small molecule diamine to the small molecule monoamine is 1:1 to 30:

1.

10. The method for preparing a hydrophilic spandex fiber according to claim 6, characterized in that, The mass concentration of the mixed amine solution is 3 wt% to 10 wt%.

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