High-elastic textile fiber and preparation process thereof

Abstract

The present invention relates to the field of synthetic fiber technology, specifically a high-elasticity textile fiber and a preparation process thereof. The high-elasticity textile fiber is prepared by melt spinning and draft winding of polyurethane-polyamide elastomer and modified diatomaceous earth masterbatch. The present invention uses terminal hydroxyl polydimethylsiloxane as a polyol, controls the molar ratio of polyurethane prepolymer and polyamide prepolymer, and obtains polyamide-polyurethane elastomer slices with good heat resistance; controls the molar ratio of isocyanate to polyol and the molar mass ratio of caprolactam and adipic acid, and obtains excellent mechanical properties of the textile fiber; utilizes 2,2-dihydroxymethylpropionic acid chain extension reaction, controls the molar ratio, and obtains a textile fiber with a moisture regain of 8.58% and strong hygroscopicity; diatomaceous earth is modified by quaternary ammonium salt compounds, and the addition ratio is adjusted, and the obtained spun fiber has good antibacterial properties.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic fibers, in particular to a high-elasticity textile fiber and a preparation process thereof. Background Art

[0002] With the advancement of society, the development of science and technology, and the improvement of living standards, people's clothing consumption concepts and market demands have undergone significant changes. The demand for fibers and textiles has gone beyond durability and aesthetics to include comfort, health, safety, protection, and environmental protection. Among the many functional textile fiber varieties, elastic fiber plays an irreplaceable role in clothing comfort, bulk, and warmth due to its ability to impart a good sense of contact with the human body. Therefore, it holds a solid position in the textile industry. Furthermore, imparting a certain degree of elasticity to textile fabrics has become an inevitable development trend in clothing textiles. Elastic fibers are mainly divided into polyester fibers, composite elastic fibers, polyolefin elastic fibers, and nylon fibers according to their type and composition.

[0003] Nylon fiber, the world's first commercialized synthetic fiber, boasts advantages such as high strength, excellent heat resistance, and high abrasion resistance, making it widely used in clothing, textiles, fasteners, and connectors. However, with technological development, nylon fiber itself suffers from poor moisture absorption and moisture regain, which affects the wearing comfort of clothing and apparel. Furthermore, nylon fiber has poor antibacterial properties, making it susceptible to bacterial growth, thus limiting its application.

[0004] Patent CN202010881729.X reports a polyurethane-nylon 6 block copolymer, a preparation method thereof, and a polyurethane-nylon 6 elastic fiber. The polyurethane-nylon 6 block copolymer is an ABA-type block copolymer. The copolymer is melt-spun to obtain a high-strength, high-resilience polyurethane nylon 6 elastic fiber. However, it does not solve the problem of poor hygroscopicity and antibacterial properties of nylon fibers.

[0005] CN201410799837.7 discloses a melt reaction preparation method for nylon polyurethane elastomer, which mainly comprises first uniformly blending amino-terminated nylon, isocyanate-terminated polyurethane, heat stabilizer, light stabilizer and water stabilizer, and then performing melt reaction through a twin-screw extruder or internal mixer to obtain nylon polyurethane elastomer. This method directly melt-blends polyurethane and nylon in an extruder, resulting in a low efficiency of copolymerization reaction, and the resulting nylon polyurethane elastomer has a tensile strength of less than 30 MPa, which is far lower than the tensile strength of practical polyamide fiber or spandex, and has poor mechanical properties.

[0006] The elastic effect of the fabric mainly depends on the characteristics of the fibers used. Currently, the most commonly used elastic fiber on the market is polyurethane fiber. However, the strength of polyurethane fiber is slightly insufficient, and its oxidation resistance and heat resistance are poor. The washing process must be kept at a low temperature and gentle mode, otherwise shrinkage or rupture will occur. In addition, the antibacterial and deodorizing effects of polyurethane fiber are not very good.

[0007] Patent CN202110724023.7 reports on spandex that is easy to dye with reactive dyes and its preparation method. The soft segment of the polyurethane elastic fiber introduces a dihydroxy polymer containing a tertiary amine group, combined with the addition of lithium organic compounds in the polyurethane elastic fiber spinning aid, thereby improving the dyeing rate of the reactive dye on the polyurethane elastic fiber. However, the elastic properties of the polyurethane fiber prepared by this method change significantly, and the added lithium-based compound will accelerate the deterioration of the polyurethane elasticity.

[0008] In summary, polyurethane fibers are prone to poor heat resistance and low antibacterial effect; nylon fibers have poor moisture absorption and regain, and insufficient antibacterial properties, which limit the application range of nylon fibers; a series of process improvements have been made to the fibers in the existing technology, but there are still problems such as insufficient elasticity, poor heat resistance, and mechanical properties that need to be improved.

[0009] Therefore, a high-elastic textile fiber and a preparation process thereof are proposed. Summary of the Invention

[0010] The object of the present invention is to provide a high-elasticity textile fiber and a preparation process thereof, wherein hydroxy-terminated polydimethylsiloxane is used as a polyol, the molar ratio of a polyurethane prepolymer to a polyamide prepolymer is controlled to be 1.3:1, the temperature of the obtained polyamide-polyurethane elastomer slice is 358°C when the mass loss is 5%, the temperature is 484°C when the mass loss is 95%, and the heat resistance is improved; by polymerizing linear hexamethylene diisocyanate with a soft segment polyol, controlling the molar ratio of isocyanate to polyol, and adjusting the molar mass ratio of caprolactam to adipic acid in the polyamide prepolymer, the obtained textile fiber is The breaking strength of the woven fiber is 7.2 cN / dtex, and the elongation at break is 85.4%; 2,2-dihydroxymethylpropionic acid is used to carry out a chain extension reaction on the polyurethane reaction system, and the molar ratio of the polyurethane reaction system to the chain extender is controlled to be 1:1.5. When the chain extension reaction temperature is 50°C, the moisture regain of the obtained textile fiber is 8.58%, and it has strong hygroscopicity; diatomaceous earth is modified by 10% quaternary ammonium salt compounds, and the addition amount of modified diatomaceous earth is 15%. The resulting spun fiber has an inhibition rate of 99.6% against Staphylococcus aureus and an inhibition rate of 99.5% against Escherichia coli, and has excellent antibacterial properties.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] A process for preparing highly elastic textile fibers, characterized in that the process for preparing highly elastic textile fibers comprises the following steps:

[0013] Dissolve isocyanate and polyol in DMF, heat to 50°C, add dibutyltin dilaurate and react for 3 hours, then add chain extender and carry out chain extension reaction at 50-100°C for 2 hours to prepare polyurethane prepolymer;

[0014] Caprolactam, deionized water, and adipic acid were placed in a reactor, reacted at 230°C and 100 rpm for 2 h, and water was removed to obtain a polyamide prepolymer.

[0015] The modified diatomite masterbatch was prepared by adding diatomite into sodium hydroxide solution and adding a modifier, stirring at 200 r / min for 2 h, centrifuging, sieving, and vacuum drying at 100° C. for 2 h.

[0016] The polyurethane prepolymer is added to the polyamide prepolymer, stirred at 60-100° C. and 300 rpm for 3 h, washed with cold water, vacuum-dried at 80° C. for 1 h, and sliced ​​to obtain polyamide-polyurethane elastomer slices;

[0017] The polyamide-polyurethane elastomer slices and the modified diatomaceous earth masterbatch are vacuum dried at 115° C. and 100 Pa for 48 hours to obtain dry slices; the dry slices are added to a two-component composite melt low-speed spinning machine for melt spinning, hot drawing, and winding to obtain high-elasticity textile fibers;

[0018] The mass ratio of the modified diatomaceous earth masterbatch to the polyamide-polyurethane elastomer slice is 1:5-10;

[0019] The molar ratio of the polyurethane prepolymer to the polyamide prepolymer is 1-1.5:1;

[0020] The molar ratio of the isocyanate to the polyol is 1-1.3:1;

[0021] The molar ratio of the caprolactam to the adipic acid is 3-10:1;

[0022] The process parameters of the heat drawing include: a drawing ratio of 1.5-4 times, a heat setting temperature of 80-120° C., and heat setting methods including pre-setting, mid-setting, and post-setting.

[0023] Preferably, the dried slices are dried to a moisture content of less than 30 ppm before spinning.

[0024] Preferably, the polyol is selected from one of polyether glycol, polypropylene glycol, polycaprolactone glycol, polytetramethylene glycol, and hydroxy-terminated polydimethylsiloxane.

[0025] Preferably, the isocyanate is selected from toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and p-xylylene diisocyanate.

[0026] Preferably, the chain extender is selected from one of butanediol, 2,2-dihydroxymethylpropionic acid, 1,6-hexanediol and trimethylolpropane.

[0027] Preferably, the modifier is selected from one of nano zinc oxide, nano silver oxide, and trimethylammonium chloride acetylhydrazine.

[0028] Preferably, the preparation of the polyurethane prepolymer comprises the following steps:

[0029] The isocyanate and polyol are dried in a vacuum drying oven at 80° C. for 2 hours to obtain a dry raw material; the polyol and the isocyanate are added into a flask and dissolved in DMF to obtain a dissolving system; the dissolving system is heated to 50° C., dibutyltin dilaurate is added thereto, and the reaction is carried out for 3 hours to obtain a reaction system; a chain extender is added into the reaction system, and the chain extension reaction is carried out at 50-80° C. for 2 hours to obtain a polyurethane prepolymer.

[0030] Preferably, the preparation of the polyamide prepolymer comprises the following steps:

[0031] Caprolactam, deionized water, and adipic acid were added to a reactor, which was sealed with nitrogen. The reaction mixture was stirred at 100 rpm and reacted at 230° C. for 2 h to obtain a reaction solution. The reaction solution was cooled and depressurized, and vacuumed for 5 min to remove moisture to obtain a polyamide prepolymer.

[0032] Preferably, the preparation of the modified diatomite masterbatch comprises the following steps:

[0033] Diatomaceous earth was weighed and added to a muffle furnace, and calcined at 450° C. for 2 h to obtain porous diatomaceous earth; the porous diatomaceous earth was added to a ball mill for wet ultrafine grinding to obtain a micron-level average particle size to obtain ground diatomaceous earth; the ground diatomaceous earth was added to 5 ml of sodium hydroxide solution, a modifier was added, and the mixture was stirred at 200 r / min for 2 h, centrifuged, sieved, and vacuum dried at 100° C. for 2 h to obtain a modified diatomaceous earth masterbatch.

[0034] Preferably, during the preparation of the modified diatomite masterbatch, the modifier accounts for 5%-15% of the mass of the diatomite.

[0035] Preferably, the two-component composite melt low-speed spinning machine for preparing fiber yarns includes polyamide-polyurethane elastomer chips and modified diatomaceous earth masterbatch passing through a hopper, screw melting, metering pump, spinning assembly, drawing treatment, oiling wheel, hot drawing, and winding.

[0036] Preferably, the operating parameters of the two-component composite melt low-speed spinning machine are: the screw section temperature is controlled at 280°C-290°C, the spinneret temperature is controlled at 240°C, the metering pump temperature is 260°C, and the pump pressure is 6 MPa.

[0037] Preferably, the two-component composite melt low-speed spinning machine includes the fiber filaments sequentially entering the unwinding wheel, low-speed drawing wheel, shaping hot box, high-speed drawing wheel, and winding wheel, and finally the fiber filaments are wound into a roll through a winding drum.

[0038] Preferably, the shaping method refers to the different positions of the shaping hot box during the stretching process, and is defined as front shaping, middle shaping and rear shaping according to whether the shaping box is located before the low-speed stretching wheel, between the low-speed stretching wheel and the high-speed stretching wheel, and after the high-speed stretching wheel.

[0039] A high-elasticity textile fiber, characterized in that: the high-elasticity textile fiber includes the polyurethane prepolymer, the polyamide prepolymer, and the modified diatomaceous earth masterbatch; the high-elasticity textile fiber is prepared by the preparation method described in any one of the above; the polyamide-polyurethane elastomer slice in the high-elasticity textile fiber has a T5% of 358°C and a T95% of 484°C; the high-elasticity textile fiber has a breaking strength of 7.2 cN / dtex and an elongation at break of 85.4%; the elastic recovery rate of the high-elasticity spun fiber at a fixed elongation of 10% is 99.6%; the moisture regain of the high-elasticity spun fiber under constant temperature and humidity for 48 hours is 8.58%; the high-elasticity spun fiber has a Staphylococcus aureus inhibition rate of 99.6% and an Escherichia coli inhibition rate of 99.5%.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention utilizes the polymerization of terminal hydroxyl polydimethylsiloxane and isocyanate, the effect of a chain extender to prepare a polyurethane prepolymer, and the polyamide prepolymer to undergo a condensation reaction to prepare a polyamide-polyurethane elastomer. The terminal hydroxyl polydimethylsiloxane molecule contains Si-O bonds, and the increase in bond energy increases the overall heat resistance of the elastomer. At the same time, the main chain of the siloxane molecule increases the interchain hydrogen bonding force, the interaction between molecular chain segments is enhanced, and the heat resistance is enhanced. The molar ratio of the polyurethane prepolymer to the polyamide prepolymer is controlled to be 1.3:1. The temperature of the obtained polyamide-polyurethane elastomer slice when the mass loss is 5% is 358°C, and the temperature when the mass loss is 95% is 457°C, showing significantly improved heat resistance.

[0042] 2. The present invention uses linear hexamethylene diisocyanate and soft segment polyol for polymerization, controls the molar ratio of isocyanate to polyol, and adjusts the molar mass ratio of caprolactam and adipic acid in the polyamide prepolymer. The use of long-chain isocyanate can effectively reduce the applied force, and the applied stress can be dispersed in the fatty linear chain. At the same time, the amount of caprolactam is increased, the number of amino groups and amide bonds in the molecule increases, the hydrogen bonding force is enhanced, and the intermolecular attraction is increased. The resulting textile fiber has a breaking strength of 7.2 cN / dtex and an elongation at break of 85.4%.

[0043] 3. This invention uses a two-component composite melt-spinning machine at low speeds to melt-spin polyamide-polyurethane elastomer chips and modified diatomaceous earth masterbatch. The mechanical properties of the textile fibers are then investigated through a drafting process. Because the number of crystallites formed in the nascent fibers extruded at low speeds is extremely small, resulting in a small number of physical crosslinks, irreversible deformation is easily produced, resulting in a low elastic recovery. The elastic recovery of the textile fibers is thus improved through the drafting process. Experimental investigations have shown that at a draft ratio of 4 and a set temperature of 100°C, the resulting spun fibers exhibit an elastic recovery of 99.6% at a fixed elongation of 10%.

[0044] 4. The present invention utilizes 2,2-dimethylolpropionic acid to carry out a chain extension reaction on a polyurethane reaction system to prepare a polyurethane prepolymer, which is subjected to a condensation reaction with a polyamide prepolymer and melt-drawn to obtain a textile fiber. By introducing a -COOH group into a chain extender, the -COOH groups free on the surface of the textile fiber bind to water molecules due to hydrogen bonding, thereby improving the hygroscopicity of the textile fiber. Simultaneously, after the chain extender chain segments are introduced into the main chain, the regularity of the molecular chain is destroyed, the hydrogen bond density between the molecular chains is reduced, the crystallinity of the fiber is decreased, and the moisture regain is increased. When the molar ratio of the polyurethane reaction system to the chain extender is controlled to be 1:1.5 and the chain extension reaction temperature is 50°C, the moisture regain of the obtained textile fiber is 8.58%, showing significantly improved hygroscopicity.

[0045] 5. The present invention utilizes modified diatomaceous earth and polyamide-polyurethane elastomer slices to produce textile fibers by melt-drawing, thereby enhancing the antibacterial properties of the textile fibers. The spinning speed and amount of modified diatomaceous earth can be controlled to stabilize the spinning process and produce spun fibers. Quaternary ammonium salt compounds can be filled into the pores of the diatomaceous earth, where the free polar groups can form hydrogen bonds with the elastomer slices, increasing compatibility and synergizing with the diatomaceous earth to enhance the fiber's antibacterial properties. When 10% by weight of the modifier and 15% by weight of the modified diatomaceous earth were added, the resulting spun fibers exhibited 99.6% inhibition against Staphylococcus aureus and 99.5% inhibition against Escherichia coli, demonstrating significantly improved antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Thermogravimetric curves of Example 5 and Comparative Examples 1-2 are shown;

[0047] Figure 2 This is a graph showing the change in elastic recovery rate under the condition of a fixed elongation of 5%-30% for Examples 25-29. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] See also Figures 1 to 2 The present invention provides a high-elastic textile fiber and a preparation process thereof, and the technical solution is as follows:

[0050] Examples 1-13

[0051] Toluene diisocyanate and polyol are dried at 80° C. for 2 hours in a vacuum drying oven to obtain a dry raw material; the dihydroxy polydimethylsiloxane and the toluene diisocyanate are added to a four-necked flask and dissolved in 2 ml of DMF to obtain a dissolving system; the dissolved system is protected by nitrogen, heated to 50° C., and 1% of a catalyst, dibutyltin dilaurate, is added and reacted for 3 hours to obtain a reaction system; a chain extender is added to the reaction system, and the system is kept at 50° C. for a chain extension reaction for 2 hours to obtain a polyurethane prepolymer.

[0052] 24 mol of caprolactam, deionized water (3% of the mass of caprolactam) and 3 mol of adipic acid were put into a 10 L nitrogen exchange reactor. The reactor was sealed and stirred at 100 rpm at 230° C. for 2 h to obtain a reaction solution. The reaction solution was cooled and depressurized, and vacuumed for 5 min to remove moisture to obtain a polyamide prepolymer.

[0053] The polyurethane prepolymer is added to the polyamide prepolymer, and the mixture is stirred at 60-100° C. and 300 rpm for 3 hours under vacuum conditions to obtain a reactant; when the melt in the reactant is transparent and has few bubbles, vacuum is applied for 10 minutes, the stirrer is turned off, the reactant is washed with supercooled water, vacuum-dried at 80° C. for 1 hour, and sliced ​​to obtain polyamide-polyurethane elastomer slices.

[0054] Diatomaceous earth was weighed and added to a muffle furnace, and calcined at 450° C. for 2 h to obtain porous diatomaceous earth; the porous diatomaceous earth was added to a ball mill for wet ultrafine grinding to obtain a micron-level average particle size to obtain ground diatomaceous earth; 10 g of the ground diatomaceous earth was added to 5 ml of sodium hydroxide solution, 1 g of nano-zinc oxide was added, the mixture was stirred at 200 r / min for 2 h, centrifuged, and dried in vacuo at 100° C. for 2 h to obtain a modified diatomaceous earth masterbatch.

[0055] Preparation of highly elastic textile fibers:

[0056] 100g of the polyamide-polyurethane elastomer chips and 20g of the modified diatomaceous earth masterbatch were dried in a vacuum drying oven at 115°C, a vacuum of 100 Pa, and a drying time of 48 hours to produce dried chips. The dried chips were then melt-spun and wound in a two-component composite melt-spinning low-speed spinning machine, and the fibers were heat-stretched to produce high-elasticity textile fibers. The spinneret used had a specification of 0.28*0.84mm and 36 holes. The spinning speed was 980m / min. The differences between Examples 1-13 are shown in Table 1.

[0057] Table 1 Differences in the dosage of components in Examples 1-13

[0058] Example Polyol types <![CDATA[n (聚氨酯) :n (聚酰胺) ]]> Reaction temperature / ℃ Example 1 Polyether diol 1.3:1 80 Example 2 polypropylene glycol 1.3:1 80 Example 3 Polycaprolactone diol 1.3:1 80 Example 4 Polytetramethylenetetrahydrofuran diol 1.3:1 80 Example 5 Hydroxyl-terminated polydimethylsiloxane 1.3:1 80 Example 6 Hydroxyl-terminated polydimethylsiloxane 1.3:1 60 Example 7 Hydroxyl-terminated polydimethylsiloxane 1.3:1 70 Example 8 Hydroxyl-terminated polydimethylsiloxane 1.3:1 90 Example 9 Hydroxyl-terminated polydimethylsiloxane 1.3:1 100 Example 10 Hydroxyl-terminated polydimethylsiloxane 1：1 80 Example 11 Hydroxyl-terminated polydimethylsiloxane 1.2:1 80 Example 12 Hydroxyl-terminated polydimethylsiloxane 1.4:1 80 Example 13 Hydroxyl-terminated polydimethylsiloxane 1.5:1 80

[0059] Comparative Example 1 refers to the preparation method and parameter conditions of Example 1, except that no polyamide prepolymer is added and only polyurethane prepolymer is used as the spinning sheet body.

[0060] Comparative Example 2 refers to the preparation method and parameter conditions of Example 1, except that no polyurethane prepolymer is added and only polyamide prepolymer is used as the spinning sheet.

[0061] Example 14 Heat resistance measurement

[0062] The polyamide-polyurethane elastomers prepared in Examples 1-13 and Comparative Examples 1-2 were tested for melting and crystallization properties using a differential calorimeter (DSC-822). Before the test, the elastomer slices were vacuum-dried at 105°C for 12 hours and then weighed 10 mg. The slices were placed in a crucible for sample preparation. Under a nitrogen atmosphere, the heating and cooling rate was maintained at 10°C / min. The test temperature was increased from 30°C to 280°C, maintained for three minutes, and then decreased from 280°C to 30°C. The melting temperature was recorded. The experimental results are shown in Table 2.

[0063] The polyamide-polyurethane elastomers prepared in Examples 1-13 and Comparative Examples 1-2 were subjected to a thermal stability test using a thermogravimetric analyzer (TGA8000). After drying at 80°C in vacuum for 12 hours, 10 mg was weighed and sampled in a crucible. The thermal stability test was performed at a heating rate of 20°C / min from 30°C to 600°C in a nitrogen atmosphere at a flow rate of 50 ml / min. The thermogravimetric curves of Example 5 and Comparative Examples 1-2 are shown in FIG. Figure 1 As shown, T 5％ 、T 95％ . T 5％ is the temperature corresponding to 5% mass loss, T 95％ is the temperature corresponding to 95% mass loss. The experimental results are shown in Table 2.

[0064] Table 2 Heat resistance test results of Examples 1-13 and Comparative Examples 1-2

[0065]

[0066] Through Table 1, Figure 1 The results show that, in Comparative Examples 1-2, only polyamide prepolymer or polyurethane prepolymer is used as the elastomer, which can be spun into fibers, but the heat resistance of the elastomer shows a significant decrease compared with Example 5; the results of Comparative Examples 1-5 show that the use of different types of polyols affects the overall heat resistance of the elastomer. The use of ester bonds and ether chains introduced destroys the regularity of the local molecular chains, further reduces the hydrogen bond density between the main chains, reduces the interaction force between the molecular chains, reduces crystallization, makes the molecular segments easier to move, and reduces the heat resistance. Since the terminal hydroxy polydimethylsiloxane molecules contain Si-O bonds, the bond energy increases, which increases the overall heat resistance of the elastomer. At the same time, the main chain of the siloxane molecule increases the hydrogen bond force between the chains, the interaction between the molecular segments is enhanced, and the heat resistance is increased. The results of Comparative Examples 1 and 6-9 show that with the increase of the reaction temperature, the melting temperature and decomposition temperature of the elastomer gradually increase. Due to the increase in temperature, the free -NCO groups in the system move Increase, the contact opportunity with the polar groups on the main chain increases, and the interaction force between the molecular chains is increased. However, with the increase of temperature, the cross-linking points generated increase, the viscosity of the elastomer increases, and the spinning process cannot be spun, affecting the processing performance; Comparing the results of Example 5 and Examples 10-13, it can be seen that with the increase of the molar ratio of the polyurethane prepolymer and the polyamide prepolymer, the melting temperature of the elastomer gradually decreases. Because at the same content, the larger the molecular weight of the polyurethane, the fewer the number of polyamide segments, and the less restriction the polyamide segments have on the polyurethane segments. The thermal properties of the polyamide prepolymer are related to the molar ratio of the amide group to the methylene group in the main chain. As the molecular weight of the polyurethane segment increases, the ester bond content in the system will increase accordingly. At the same time, the polar groups contained in the polyurethane further increase the intermolecular force, the regularity between the molecular chains decreases, the melting temperature of the elastomer decreases, the heat resistance decreases, and the increase in the amount of polyurethane reduces the viscosity of the system, making it difficult to spin in the later stage. Comprehensive Table 2, Figure 1 The results show that when the polyurethane prepolymer is prepared using terminal hydroxyl polydimethylsiloxane as the polyol, and n(polyurethane):n(polyamide)=1.3:1, the temperature of the obtained polyamide-polyurethane elastomer slices when the mass loss is 5% is 358°C, and the temperature when the mass loss is 95% is 484°C.

[0067] Examples 15-23 refer to the preparation method and parameter conditions of Example 5, with the differences as shown in Table 3.

[0068] Comparative Example 3 refers to the preparation method and parameter conditions of Example 5, except that no polyamide prepolymer is added and only polyurethane prepolymer is used as the spinning sheet.

[0069] Comparative Example 4 refers to the preparation method and parameter conditions of Example 5, except that no polyurethane prepolymer is added and only polyamide prepolymer is used as the spinning sheet.

[0070] Example 24 Tensile Properties Test

[0071] The tensile properties of the fibers obtained in Examples 14-23 and Comparative Examples 3-4 were tested using a YG020B electronic single yarn strength tester produced by Changzhou Bafang Lishi Textile Instrument Co., Ltd. The clamping distance was 100 mm, the pre-tension was 0.05 cN / dtex, and the tensile speed was 500 mm / min. The test results are shown in Table 3.

[0072] Table 3 Tensile performance test of Examples 15-23 and Comparative Examples 3-4

[0073]

[0074]

[0075] From the results in Table 3, it can be seen that the breaking strength and elongation at break of the spun fibers prepared by using only polyamide prepolymer or polyurethane prepolymer as elastomer in Comparative Examples 3-4 are significantly lower than those in Examples 15-23; from the results of Comparative Examples 15-18, it can be seen that the spun fibers finally prepared by using polyurethane prepolymer prepared by hexamethylene diisocyanate have significantly improved elongation at break and breaking strength. Since the use of long-chain isocyanates can effectively reduce the applied force, the applied stress can be dispersed in the fatty straight chain, thereby increasing the breaking strength of the spun material. At the same time, the dispersed applied force can improve the ductility of the spinning, thereby improving the elongation at break; aromatic isocyanates and alicyclic isocyanates effectively increase the strength of the elastomer due to their cyclic rigid structure, but due to the conjugation effect, the applied external force further enhances the intermolecular force in the structural system. , resulting in a decrease in the breaking strength of spinning; it can be seen from the results of Example 15 and Examples 18-19 that with the increase of the molar ratio of isocyanate and polyol, the elongation at break and the breaking strength of spinning tend to remain unchanged; Comparative Example 15 and Examples 20-23, with the increase of the molar amount of caprolactam, the soft segment structure in the system is reduced, the dispersion of the force is weakened, and the breaking strength of the spinning material gradually decreases. Due to the increase in the amount of caprolactam, the intramolecular hydrogen bond force is enhanced, the intermolecular attraction is increased, and the elongation at break increases; in summary, when hexamethylene diisocyanate is used to prepare a polyurethane prepolymer, and when n(isocyanate):n(polyol)=1.2:1 and n(caprolactam):n(adipic acid)=8:1 are maintained, the obtained textile fiber has a breaking strength of 7.2 cN / dtex and an elongation at break of 85.4%, which has significantly improved mechanical properties.

[0076] Examples 25-35

[0077] 3.6 mol of hexamethylene diisocyanate and 3 mol of terminal hydroxyl polydimethylsiloxane were dried in a vacuum drying oven at 80°C for 2 hours to prepare a dry raw material; the dihydroxy polydimethylsiloxane and the hexamethylene diisocyanate were added to a four-necked flask and dissolved in 2 ml of DMF to prepare a dissolving system; the dissolved system was protected by nitrogen, heated to 50°C, and 0.036 mol of dibutyltin dilaurate was added and reacted for 3 hours to prepare a reaction system; a chain extender was added to the reaction system, and the reaction was carried out at 50°C for chain extension reaction for 2 hours to prepare a polyurethane prepolymer.

[0078] 24 mol of caprolactam, deionized water (3% of the mass of caprolactam) and 3 mol of adipic acid were put into a 10 L nitrogen exchange reactor. The reactor was sealed and stirred at 100 rpm at 230° C. for 2 h to obtain a reaction solution. The reaction solution was cooled and depressurized, and vacuumed for 5 min to remove moisture to obtain a polyamide prepolymer.

[0079] 1.3 mol of the polyurethane prepolymer is added to 1 mol of the polyamide prepolymer, and the mixture is stirred at 300 rpm and 60-100° C. for 3 h under vacuum conditions to obtain a reactant. When the melt in the reactant is transparent and has few bubbles, vacuum is applied for 10 min, the stirrer is turned off, the reactant is washed with supercooled water, vacuum-dried at 80° C. for 1 h, and sliced ​​to obtain polyamide-polyurethane elastomer slices.

[0080] Diatomaceous earth was weighed and added to a muffle furnace, and calcined at 450° C. for 2 h to obtain porous diatomaceous earth; the porous diatomaceous earth was added to a ball mill for wet ultrafine grinding to obtain a micron-level average particle size to obtain ground diatomaceous earth; 10 g of the ground diatomaceous earth was added to 5 ml of sodium hydroxide solution, 1 g of nano-zinc oxide was added, the mixture was stirred at 200 r / min for 2 h, centrifuged, and dried in vacuo at 100° C. for 2 h to obtain a modified diatomaceous earth masterbatch.

[0081] Preparation of highly elastic textile fibers:

[0082] The polyamide-polyurethane elastomer slices and the modified diatomaceous earth masterbatch are placed in a vacuum drying oven and dried at a temperature of 115° C., a vacuum degree of 100 Pa, and a drying time of 48 hours to obtain dried slices; the dried slices are added to a two-component composite melt low-speed spinning machine for melt spinning and winding, and the fibers are hot-stretched to obtain high-elastic textile fibers.

[0083] The differences in the hot drawing process parameters of Examples 25-35 are shown in Table 4.

[0084] Comparative Example 5 refers to the preparation method and parameter conditions of Example 29, except that no wire drawing treatment is performed.

[0085] Example 36 Elasticity Performance Measurement

[0086] Tensile testing was performed using a 5843 universal tensile testing machine manufactured by INSTRON (USA) at a fixed elongation of 5% to 30%, a clamping distance of 100 mm, and a tensile speed of 500 mm / min. The elastic recovery rate was calculated using the following formula.

[0087] Elastic recovery rate (%) = L0-L2 / L0×100%

[0088] Wherein: L0 is the set elongation value of the fiber; L2 is the elongation value corresponding to the fiber when it is stretched to the pre-tension after relaxation recovery. The elastic recovery rate when the set elongation is 10% is shown in Table 4; the elastic recovery rate changes under the conditions of 5%-30% of the set elongation of Examples 25-29 are shown in the figure Figure 2 shown.

[0089] Table 4 Elastic recovery rate of Examples 25-35 and Comparative Example 5

[0090]

[0091] From the results in Table 4, it can be seen that the mechanical properties and elastic properties of the spinning material without drawing treatment in Comparative Example 5 have obvious changes in the overall performance compared with those of Examples 25-35; from the results in Examples 25-29, it can be seen that with the increase of the drawing ratio, the macromolecular chains in the amorphous region are arranged more regularly along the axial direction, the orientation degree increases, and the intermolecular force increases, so with the increase of the drawing ratio, the breaking strength increases and the breaking elongation decreases; since the number of crystallites formed by the primary fibers extruded at low speed is very small, the corresponding physical cross-linking points are small, and irreversible deformation is easily generated, and the elastic recovery rate is low; and when the fibers are subjected to a certain drawing force, the hard segments in the polymer are oriented and crystallized, and the ability to resist deformation is enhanced, so the elastic recovery rate increases, but with the increase of the drawing ratio, the elastic recovery rate is not greatly affected; from the results in Examples 25 and 30-31, it can be seen that since the pre-setting is the drawing of the fibers after heat setting, heat setting can promote The degree of phase separation is improved, more physical cross-linking points are formed, and orientation and crystallization occur during the drawing process, the degree of phase separation is further improved, the stability of the polyether elastic system is improved, the elastic recovery rate is increased, and the mid-setting and post-setting have little effect on the elastic recovery rate; however, post-setting is that the fiber is heat-set after cold drawing, and the macromolecular chains in the fiber are prone to dissociation, resulting in a decrease in breaking strength and an increase in breaking elongation; Comparing the results of Example 25 and Examples 32-35, it can be seen that as the heat setting temperature increases, the molecular movement inside the fiber intensifies, more macromolecular chains in the amorphous region are arranged in order, the force between the molecular chains is enhanced, and the molecular chains are not easy to slip, so the fiber breaking strength increases, the elongation at break decreases, and the elastic recovery rate shows a trend of increasing. However, when the reaction temperature rises to 110°C, the higher heat setting temperature increases the degree of fiber deorientation, weakens the degree of phase separation, and increases the irreversible plastic deformation of the fiber; through Figure 2 The results further demonstrate that increasing the draft ratio has little effect on the elastic recovery, but the elastic recovery of the spun fibers prepared in the examples gradually decreases with increasing fixed elongation. When the fixed elongation changes by 30%, the elastic recovery of the spun fibers prepared in Example 29 is 85%. From the results in Table 4, it can be seen that the elastic recovery of the spun fibers prepared at a draft ratio of 4 and a medium set temperature of 100°C at a fixed elongation of 10% is 99.6%.

[0092] Examples 37-46 refer to the preparation method and parameter conditions of Example 29, with the differences shown in Table 5

[0093] Comparative Example 6 refers to the preparation method and parameter conditions of Example 29, except that the chain extender is not added for chain extension treatment. Example 47 Hygroscopicity Test

[0094] Referring to GB / T 6503-2008 Test Method for Moisture Regain of Chemical Fibers, Examples 37-46 and Comparative Example 6 were dried in a 105°C forced air oven for 12 hours. A fiber sample with a mass of m0 was weighed and conditioned in a constant temperature and humidity chamber at 20°C and 65% relative humidity for 48 hours. The balanced fiber mass was weighed as m1. The average value of the three tests was taken, and the fiber moisture regain, Mr, was calculated according to the following formula. The results are shown in Table 5. Mr = m1 - m0 / m0 × 100%

[0095] Table 5 Hygroscopicity test of Examples 37-46 and Comparative Example 6

[0096]

[0097] From the results in Table 5, it can be seen that in Comparative Example 6, the polyurethane is chain extended without using a chain extender, and the moisture regain of the obtained textile fiber material is significantly reduced compared with Examples 37-46. The addition of a chain extender can effectively improve the moisture absorption and moisture regain properties of the fiber, and the fiber fabric with higher hygroscopicity is more comfortable to wear; from the results of Comparative Examples 37-40, it can be seen that the use of aliphatic diols and alicyclic alcohols as chain extenders can improve the moisture regain, but the moisture regain and hygroscopicity of polyols containing polar groups in the branched chains need to be improved. Due to the introduction of -COOH groups in the chain extender, the -COOH free on the surface of the textile fiber and the water molecules are combined with each other due to hydrogen bonding, thereby improving the hygroscopicity of the textile fiber; from the results of Examples 37 and 41-43, it can be seen that with the increase of the chain extender content, the moisture regain of the textile fiber material gradually increases. This is due to the increase in crystallinity. Moisture absorption mainly occurs on the surface of the amorphous region and the crystalline region. The larger the amorphous region, the lower the crystallinity, the greater the moisture regain of the fiber, and the chain extender After the chain segment is introduced into the main chain, the regularity of the molecular chain is destroyed, the hydrogen bond density between the molecular chains is reduced, the crystallinity of the fiber is reduced, and the moisture regain is increased. As the chain extender is added in excess, the polar -COOH groups in the molecule increase, and the -COOH groups in the textile fiber are cross-linked with the -NCO groups, further affecting the overall mechanical properties of the fiber. Comparing the results of Example 37 and Examples 44-46, it can be seen that with the increase of the reaction temperature, the moisture regain first increases and then decreases. Since with the increase of the reaction temperature, the -COOH groups in the system are chemically cross-linked with the polar groups in the chain segments, the free -COOH groups on the fiber surface end are reduced, and the hydrogen bonding force on the water molecules is weakened, showing a significantly reduced moisture regain. From the results of Table 5, it can be seen that when 2,2-dihydroxymethylpropionic acid is used as the chain extender, the molar ratio of the reaction system to the chain extender is maintained at 1:1.5, and the chain extension reaction temperature is 50°C, the moisture regain of the obtained textile fiber is 8.58%, showing significantly improved hygroscopic properties.

[0098] Examples 47-53

[0099] 3.6 mol of hexamethylene diisocyanate and 3 mol of terminal hydroxyl polydimethylsiloxane were dried at 80° C. for 2 h in a vacuum drying oven to prepare a dry raw material; the dihydroxy polydimethylsiloxane and the hexamethylene diisocyanate were added to a four-necked flask and dissolved in 2 ml of DMF to prepare a dissolving system; the dissolved system was protected by nitrogen, heated to 50° C., and a catalyst, dibutyltin dilaurate, was added and reacted for 3 h to prepare a reaction system; 9 mol of a chain extender was added to the reaction system, and the reaction system was kept at 50° C. for a chain extension reaction for 2 h to prepare a polyurethane prepolymer.

[0100] 24 mol of caprolactam, deionized water (3% of the mass of caprolactam) and 3 mol of adipic acid were put into a 10 L nitrogen exchange reactor. The reactor was sealed and stirred at 100 rpm at 230° C. for 2 h to obtain a reaction solution. The reaction solution was cooled and depressurized, and vacuumed for 5 min to remove moisture to obtain a polyamide prepolymer.

[0101] 1.3 mol of the polyurethane prepolymer is added to 1 mol of the polyamide prepolymer, and the mixture is stirred at 300 rpm and 60-100° C. for 3 h under vacuum conditions to obtain a reactant. When the melt in the reactant is transparent and has few bubbles, vacuum is applied for 10 min, the stirrer is turned off, the reactant is washed with supercooled water, vacuum-dried at 80° C. for 1 h, and sliced ​​to obtain polyamide-polyurethane elastomer slices.

[0102] Diatomaceous earth was weighed and added to a muffle furnace, and calcined at 450° C. for 2 h to obtain porous diatomaceous earth; the porous diatomaceous earth was added to a ball mill for wet ultrafine grinding to obtain a micron-level average particle size to obtain ground diatomaceous earth; the ground diatomaceous earth was added to 5 ml of sodium hydroxide solution, a modifier was added, and the mixture was stirred at 200 r / min for 2 h, centrifuged, sieved, and vacuum dried at 100° C. for 2 h to obtain a modified diatomaceous earth masterbatch.

[0103] Preparation of highly elastic textile fibers:

[0104] The polyamide-polyurethane elastomer chips and the modified diatomaceous earth masterbatch were dried in a vacuum drying oven at 115°C, a vacuum of 100 Pa, and a drying time of 48 hours to produce dried chips. The dried chips were then melt-spun and wound in a two-component composite melt-spinning machine, and the fibers were then hot-drawn to produce highly elastic textile fibers. The relationship between the amount of modified diatomaceous earth added and spinnability is shown in Table 6.

[0105] Table 6 Relationship between modified diatomite dosage and spinnability

[0106] Spinning speed m(elastomer slice): m(modified diatomaceous earth) Spinnability 1100 100:20 Spinning difficulties 1050 100:20 Spinning difficulties 1000 100:20 Severe decapitation 1000 100:15 Reduced end breakage and difficult winding 950 100:20 Increased decapitation 950 100:15 Spinning is stable and winding is normal 950 100:10 Winding is easy to break

[0107] Examples 47-53 were prepared and synthesized with reference to the spinning speed and addition ratio shown in Table 6, and the differences are shown in Table 7

[0108] Comparative Example 7 refers to the preparation method and parameter conditions of Example 47, except that no modifier is added to modify the diatomaceous earth.

[0109] Comparative Example 8 refers to the preparation method and parameter conditions of Example 47, except that modified diatomaceous earth is not added.

[0110] Example 54 Antibacterial Test

[0111] Staphylococcus aureus and Escherichia coli were selected as test strains, and the two bacteria were suspended in a phosphate buffer at a concentration of 100 μmol / L and pH = 7 to prepare the required bacterial solution. The bacterial solution was dropped onto the textile fibers prepared in Examples 47-53 and Comparative Examples 7-8, and another piece of textile fiber was stacked in the form of a sandwich and pressed with a sterile iron press for 10 minutes. The textile fiber undergoing the antibacterial test was exposed to sunlight for 30 minutes, then placed in a centrifuge tube with a sterile sodium thiosulfate solution at a concentration of 0.03 mol / L and shaken for 5 minutes. The above solution was then continuously diluted with 100 μmol / L, pH = 7 phosphate buffer, and the diluted solution was placed in a culture medium and cultured at a constant temperature of 37°C for 24 hours. Finally, the number of surviving bacterial colonies was counted and the antibacterial rate was calculated. The test results are shown in Table 7.

[0112] Table 7 Antibacterial performance test results of Examples 47-53 and Comparative Examples 7-8

[0113]

[0114]

[0115] From the results in Table 6, it can be seen that the amount of modified diatomite added directly affects the stability of the spinning state. With the increase of the spinning speed, the spinning stability is poor. Too fast spinning speed reduces the compatibility of the elastomer slices and diatomite, and the free inorganic particles affect the spinning stability. If the amount of modified diatomite added is too low, the function of the fiber cannot achieve the expected effect, and it is easy to break during the winding process. If too much is added, the viscosity of the spinning solution will be greatly reduced, resulting in an unstable spinning state, prone to undesirable phenomena such as broken wire and roller wrapping, and ultimately reducing the fiber spinnability. It was finally determined that when the addition ratio was 15% and the spinning speed was controlled at 950m / min, there were fewer broken ends and the spinning state was controllable. From the results in Table 7, it can be seen that the spun fiber prepared in Comparative Example 8 without adding modified diatomite almost did not show antibacterial properties, while the spun fiber prepared in Comparative Example 7 with only adding diatomite showed antibacterial properties. The antibacterial performance is significantly improved compared with Comparative Example 8, but there is still a significant gap relative to Examples 47-53. The modifier can be filled in the pore structure of the diatomite and synergistically exert antibacterial properties with the diatomite; the results of Examples 47-49 show that the use of nano-inorganic substances has significantly improved antibacterial properties relative to quaternary ammonium compounds. Since the nano-inorganic substances have poor compatibility with the elastomer during the spinning process, the quaternary ammonium compounds are filled in the pores, and the free polar groups can produce hydrogen bonds with the elastomer slices, thereby increasing the compatibility and exhibiting more excellent antibacterial properties; the results of Examples 47 and 50-53 show that with the increase of the mass ratio of the modifier, the antibacterial properties of the textile fibers gradually increase and tend to be stable. With the addition of quaternary ammonium compounds, the internal pores of the diatomite are filled, and the polar groups are free on the surface of the diatomite, exerting antibacterial properties. From the results in Tables 6 and 7, it can be seen that the spun fiber obtained by modifying the diatomaceous earth with 10% trimethylammonium chloride acetohydrazide and adding 15% modified diatomaceous earth has an inhibition rate of 99.6% against Staphylococcus aureus and 99.5% against Escherichia coli, showing significantly improved antibacterial properties.

[0116] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing highly elastic textile fibers, characterized in that: The preparation process of the highly elastic textile fiber comprises the following steps: Hexamethylene diisocyanate and hydroxyl-terminated polydimethylsiloxane were dissolved in DMF, heated to 50°C, dibutyltin dilaurate was added and reacted for 3 hours, 2,2-dimethylolpropionic acid was added, and chain extension reaction was carried out at 50-100°C for 2 hours to prepare a polyurethane prepolymer; Caprolactam, deionized water, and adipic acid were placed in a reactor, reacted at 230°C and 100 rpm for 2 h, and water was removed to obtain a polyamide prepolymer. The modified diatomite masterbatch is prepared by adding diatomite to a sodium hydroxide solution, adding trimethylammonium chloride acetylohydrazide, stirring at 200 r / min for 2 hours, centrifuging, sieving, and vacuum drying at 100° C. for 2 hours. In the preparation process of the modified diatomite masterbatch, the trimethylammonium chloride acetylohydrazide accounts for 5% to 15% of the mass of the diatomite. The polyurethane prepolymer is added to the polyamide prepolymer, stirred at 60-80° C. and 300 rpm for 3 hours, washed with cold water, vacuum-dried at 80° C. for 1 hour, and sliced ​​to obtain polyamide-polyurethane elastomer slices; The polyamide-polyurethane elastomer slices and the modified diatomaceous earth masterbatch are vacuum dried at 115° C. and 100 Pa for 48 hours to obtain dried slices; the dried slices are added to a two-component composite melt low-speed spinning machine for melt spinning, hot drawing, and winding to obtain high-elasticity textile fibers; the spinning speed of the melt spinning is 950 m / min; The mass ratio of the modified diatomite masterbatch to the polyamide-polyurethane elastomer slice is 15:100; The molar ratio of the polyurethane prepolymer to the polyamide prepolymer is 1.3-1.5:1; The molar ratio of the hexamethylene diisocyanate to the hydroxy-terminated polydimethylsiloxane is 1-1.3:1; The molar ratio of the caprolactam to the adipic acid is 3-10:1; The diatomaceous earth was weighed and added to a muffle furnace, and calcined at 450° C. for 2 h to obtain porous diatomaceous earth; the porous diatomaceous earth was added to a ball mill for wet ultrafine grinding to obtain a micron-level average particle size to obtain ground diatomaceous earth; the ground diatomaceous earth was added to 5 ml of the sodium hydroxide solution, and trimethylammonium chloride acetylohydrazide was added, and the mixture was stirred at 200 r / min for 2 h, centrifuged, sieved, and vacuum dried at 100° C. for 2 h to obtain a modified diatomaceous earth masterbatch; The process parameters of the heat drawing include: a drawing ratio of 1.5-4 times, a heat setting temperature of 80-120° C., and heat setting methods including pre-setting, mid-setting, and post-setting.

2. A highly elastic textile fiber, characterized by: The high-elastic textile fiber comprises a polyurethane prepolymer, a polyamide prepolymer and a modified diatomaceous earth masterbatch; the high-elastic textile fiber is prepared by the preparation method according to claim 1.

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