Two-component spunbonded non-woven fabric and production process thereof

Abstract

The invention provides a bi-component spun-bonded non-woven fabric and a production process thereof, and belongs to the technical field of non-woven fabrics. The non-woven fabric is composed of bi-component fibers of a skin-core composite structure, the skin layer of the bi-component fibers is composite polypropylene, and the core layer of the bi-component fibers is polycaprolactam; the preparation method of the composite polypropylene comprises the steps of polypropylene hydrophilic treatment, starch functional treatment and compounding. The hydrophilic treatment of polypropylene comprises the following steps: adding benzoyl peroxide, an antioxidant and ethylene bis stearamide into polypropylene, stirring for 20-25 minutes, adding polyethylene glycol monoallyl ether, stirring for 10-15 minutes, adding polyethylene glycol monoallyl ether again to obtain a polypropylene mixture, putting the polypropylene mixture into a twin-screw extruder, carrying out melt extrusion, and carrying out extrusion molding to obtain the polypropylene material. Hydrophilic polypropylene is obtained; the non-woven fabric is high in water absorption rate, short in liquid penetration time and excellent in strength and chemical stability resistance.

Description

Technical Field

[0001] This invention belongs to the field of nonwoven fabric technology, specifically relating to a bicomponent spunbond nonwoven fabric and its production process. Background Technology

[0002] Nonwoven fabric is a type of fabric formed without spinning or weaving. It is made by arranging short textile fibers or filaments in a directional or random manner to form a web structure, and then bonding them together using mechanical, thermal, or chemical methods. Spunbonding is one of the most important production processes for nonwoven fabrics. Its principle is to melt, spin, and stretch a polymer so that the filaments are directly laid into a web, and then consolidated to form a fabric-like material. Bicomponent spunbond nonwoven fabrics refer to nonwoven materials made by combining two polymer chips with different chemical compositions or properties in a specific geometric shape. Among them, the core-sheath structure is the most common, usually with one polymer as the sheath and the other as the core layer. This structure can achieve complementary properties between the two polymers, realizing comprehensive performance that cannot be achieved by a single polymer. It is widely used in the fields of medical protection, hygiene products, construction, agriculture, furniture and filter materials.

[0003] The existing technology in the production process of bicomponent spunbond nonwoven fabrics has the following technical defects: 1. The two polymers have poor compatibility, mismatched melt viscosity, and poor interfacial bonding strength, which can easily lead to uneven delamination of the core and skin. This can easily cause relative slippage or even glass problems, thus affecting the strength and uniformity of the product. 2. In the airflow stretching step, the airflow field is unevenly distributed, and the fibers are prone to problems such as entanglement or uneven stretching. A high stretching ratio leads to a large number of cracks inside the fibers, thereby reducing the breaking elongation of the product. 3. The two polymers have different melting points. During the melt extrusion stage, the low-melting-point polymer degrades excessively, while the high-melting-point polymer does not melt completely, which can easily lead to spinning interruption, which in turn causes component blockage and unstable production.

[0004] CN118007321A discloses a spunbond nonwoven fabric with high absorbency for wet wipes and its preparation method. It is composed of bicomponent fibers with a core-sheath composite structure. The sheath layer of the bicomponent fibers is modified polypropylene, and the core layer is polypropylene. The modified polypropylene is maleic anhydride-chitosan / carboxyl-terminated polyethylene glycol modified polypropylene, which is prepared by first melt-grafting polypropylene with maleic anhydride, and then reacting it sequentially with chitosan and carboxyl-terminated polyethylene glycol. This patent obtains maleic anhydride-chitosan / carboxyl-terminated polyethylene glycol modified polypropylene through a chemical reaction, and then performs core-sheath composite spinning, cooling, stretching, web laying, and hot rolling with the modified polypropylene to obtain a spunbond nonwoven fabric with high absorbency and good mechanical properties. This spunbond nonwoven fabric is suitable for wiping high-precision instruments, especially medical precision instruments.

[0005] However, the spunbond nonwoven fabric produced by this patent mainly improves the water absorption rate and shortens the liquid penetration time, but its strength is poor and its chemical stability is poor, and its service life is significantly shortened in acid and alkaline environments. Summary of the Invention

[0006] To address the technical problems existing in the prior art, this invention provides a bicomponent spunbond nonwoven fabric and its production process, which improves water absorption while ensuring strength performance, and also enhances chemical resistance and production stability.

[0007] To address the aforementioned technical problems, the present invention adopts the following technical solution: A bicomponent spunbond woven fabric is composed of bicomponent fibers with a core-sheath composite structure, wherein the sheath of the bicomponent fibers is a composite polypropylene and the core is polycaprolactam. The preparation method of the composite polypropylene includes polypropylene hydrophilic treatment, starch functional treatment, and a composite step, as detailed below: The hydrophilic treatment step of polypropylene is as follows: Polypropylene is placed in a high-speed mixer, and the stirring speed is controlled at 800-1000 rpm. Then, benzoyl peroxide, antioxidant, and ethylene bis-stearamide are added, and the mixture is stirred for 20-25 minutes. Polyethylene glycol monoallyl ether is added while stirring, and stirring is continued for 10-15 minutes. Polyethylene glycol monoallyl ether is added again to obtain a polypropylene mixture. The polypropylene mixture is placed in a twin-screw extruder for melt extrusion, and the extrusion temperature is controlled at 150-155℃, 165-170℃, 175-180℃, and 170-172℃, and the screw speed is 40-45 rpm. After washing and drying, hydrophilic polypropylene is obtained. The polypropylene has a melt flow index of 12-18 g / 10 min at 230°C and 2.16 kg. The antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1-2; The number-average molecular weight of the polyethylene glycol monoallyl ether is 900-1100; The mass ratio of the polypropylene, benzoyl peroxide, antioxidant, ethylene bis-stearamide, polyethylene glycol monoallyl ether added once and the polyethylene glycol monoallyl ether added twice is 100:0.25-0.30:0.8-1.0:0.15-0.20:3.8-4.2:3.8-4.2.

[0008] The starch functionalization process is as follows: corn starch is placed in deionized water, Tween 80 is added, and the mixture is stirred evenly. Then, 8-12 wt% sodium hydroxide solution is added to adjust the pH to 9-10. The temperature is raised to 50-53℃, sodium hypochlorite is added, and the mixture is stirred for 2.5-3.0 hours. After stirring, 10-12 wt% hydrochloric acid solution is added to adjust the pH to 6.5-7.0. After washing and drying, oxidized starch is obtained. The oxidized starch is placed in deionized water, stirred evenly, and then 8-12 wt% sodium hydroxide solution is added to adjust the pH to 10.0-10.5. Polyethylene glycol diglycidyl ether is added, and the temperature is raised to 58-62℃ at a rate of 1.5-2.0℃ / min. The mixture is kept warm and stirred at 380-400 rpm for 3.0-3.5 hours. After filtration, washing, and drying, functional starch is obtained. The corn starch has a particle size of 1-2 μm; The mass-to-volume ratio of corn starch, deionized water, Tween 80, and sodium hypochlorite is 10g:80-100g:0.2-0.3g:1.5-2.0mL; The mass ratio of oxidized starch, deionized water, and polyethylene glycol diglycidyl ether is 10-12:100-110:1.2-1.5.

[0009] The compounding step is as follows: add functional starch to deionized water, raise the temperature to 75-80℃, stir evenly, add kH550 silane coupling agent, continue stirring for 1.5-2.0h, wash and dry to obtain pretreated functional starch; The mass ratio of the functional starch, deionized water, and kH550 silane coupling agent is 10:80-90:0.8-1.0; Pretreated functional starch was added to deionized water and stirred until homogeneous to obtain a pretreated functional starch solution. Hydrophilic polypropylene was added to xylene, the temperature was raised to 85-90℃, and after stirring until homogeneous, it was added to the pretreated functional starch solution at 750-800 rpm. The mixture was ultrasonically dispersed for 25-30 min at an ultrasonic power of 100-120 W and an ultrasonic frequency of 30-35 kHz. After ultrasonic dispersion, the mixture was dried to obtain composite polypropylene. In the pretreated functional starch solution, the mass ratio of pretreated functional starch to deionized water is 3-5:50. The mass ratio of the hydrophilic polypropylene, xylene, and pretreated functional starch solution is 15-20:120:53-55.

[0010] A production process for a two-component spunbond nonwoven fabric involves placing a composite polypropylene in a twin-screw extruder, controlling the extrusion temperature at 145-150℃, 160-165℃, 165-170℃, and 168-172℃, and the screw speed at 60-70 rpm. The resulting material then enters the sheath cavity of a two-component spinning box. Polycaprolactam is then placed in the twin-screw extruder, controlling the base temperature at 185-190℃, 210-215℃, 225-230℃, and 225-2... At 30℃ and a screw speed of 60-70 rpm, the fibers enter the core cavity of the bicomponent spinning box. The mass ratio of the sheath to the core is controlled at 1:1.3-1.5 for spinning. The sheath spinning temperature is 170-175℃, and the core spinning temperature is 230-235℃. After side-blowing cooling, drawing, and web formation, a fiber web with a fineness of 1.2-1.5 dtex is obtained. The fiber web is then hot-rolled at 145-150℃ to obtain a basis weight of 20-25 g / m². 2 Nonwoven fabric.

[0011] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0012] 1. This invention uses polyethylene glycol monoallyl ether to modify polypropylene. The double bonds of polyethylene glycol monoallyl ether react with polypropylene free radicals to achieve the free distribution of hydroxyl groups in the polypropylene molecular chain. Furthermore, the polyoxyethylene segments of polyethylene glycol monoallyl ether are hydrophilic groups, thereby improving the hydrophilicity of polypropylene. Then, starch is used as a filler and is functionalized by oxidative carboxylation of starch, resulting in a large number of carboxyl groups on the starch surface. Then, polyethylene glycol diglycidyl ether is added to introduce epoxy groups, which can undergo ring-opening reaction with the carboxyl groups of starch, introducing polyethylene glycol segments and enhancing the similarity and compatibility with hydrophilic polypropylene. In the composite step, kH550 silane coupling agent is introduced to achieve cross-linking of functional starch and hydrophilic polypropylene, constructing a composite structure. This enhances the compatibility and dispersibility of starch and polypropylene, improves the homogeneity of the product, enhances strength properties, improves hydrophilicity, and ensures stability under chemical conditions. 2. The bicomponent spunbond nonwoven fabric prepared by this invention has a water absorption ratio of 723-731% and a liquid penetration time of 1.82-1.97s; 3. The bicomponent spunbond nonwoven fabric prepared by this invention has a longitudinal tear strength of 22.8-24.5N, a transverse tear strength of 20.1-21.3N, a longitudinal breaking strength of 48.5-50.2N, and a transverse breaking strength of 36.3-37.6N. 4. The bicomponent spunbond nonwoven fabric prepared by this invention is immersed in 6 times its mass of 8wt% hydrochloric acid solution for 12 hours, removed and dried, then immersed in 8wt% sodium hydroxide solution for 12 hours, removed and dried, and tested again. The longitudinal tear strength is 21.6-23.6N, the transverse tear strength is 18.9-20.2N, the longitudinal breaking strength is 45.8-18.1N, and the transverse breaking strength is 34.1-35.7N. Detailed Implementation

[0013] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.

[0014] Example 1: A bicomponent spunbond nonwoven fabric and its production process A bicomponent spunbond woven fabric is composed of bicomponent fibers with a core-sheath composite structure, wherein the sheath of the bicomponent fibers is a composite polypropylene and the core is polycaprolactam. The preparation method of the composite polypropylene includes polypropylene hydrophilic treatment, starch functional treatment, and a composite step, as detailed below: The hydrophilic treatment step for polypropylene is as follows: 100g of polypropylene is placed in a high-speed mixer, and the stirring speed is controlled at 800rpm. Then, 0.25g of benzoyl peroxide, 0.8g of antioxidant, and 0.15g of ethylene bis-stearamide are added, and the mixture is stirred for 20min. While stirring, 3.8g of polyethylene glycol monoallyl ether is added, and the mixture is stirred for another 10min. Then, another 3.8g of polyethylene glycol monoallyl ether is added to obtain a polypropylene mixture. The polypropylene mixture is then placed in a twin-screw extruder for melt extrusion, and the extrusion temperature is controlled at 150℃, 165℃, 175℃, and 170℃, and the screw speed is 40rpm. After washing and drying, hydrophilic polypropylene is obtained. The polypropylene has a melt flow index of 12 g / 10 min at 230°C and 2.16 kg. The antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 1:2; The number-average molecular weight of the polyethylene glycol monoallyl ether is 900.

[0015] The starch functionalization process is as follows: 10g of corn starch is placed in 80g of deionized water, 0.2g of Tween 80 is added, and the mixture is stirred evenly. Then, 8wt% sodium hydroxide solution is added to adjust the pH to 9, the temperature is raised to 50℃, 1.5mL of sodium hypochlorite is added, and the mixture is stirred for 2.5h. After stirring, 10wt% hydrochloric acid solution is added to adjust the pH to 6.5. After washing and drying, oxidized starch is obtained. 10g of oxidized starch is placed in 100g of deionized water, stirred evenly, 8wt% sodium hydroxide solution is added to adjust the pH to 10, 1.2g of polyethylene glycol diglycidyl ether is added, the temperature is raised to 58℃ at a rate of 1.5℃ / min, and the mixture is kept at 380rpm and stirred for 3.0h. After filtration, washing, and drying, functional starch is obtained. The corn starch has a particle size of 1 μm.

[0016] The compounding step is as follows: 10g of functional starch is added to 80g of deionized water, the temperature is raised to 75℃, and after stirring evenly, 0.8g of kH550 silane coupling agent is added, and stirring is continued for 1.5h. After washing and drying, pretreated functional starch is obtained. 3g of pretreated functional starch was added to 50g of deionized water and stirred until homogeneous to obtain a pretreated functional starch solution. 15g of hydrophilic polypropylene was added to 120g of xylene, the temperature was raised to 85℃, and after stirring until homogeneous, it was added to 53g of pretreated functional starch solution at 750rpm. The mixture was ultrasonically dispersed for 25min at an ultrasonic power of 100W and an ultrasonic frequency of 30kHz. After ultrasonic dispersion, the mixture was dried to obtain composite polypropylene.

[0017] A production process for a two-component spunbond nonwoven fabric involves placing composite polypropylene in a twin-screw extruder, controlling the extrusion temperature at 145℃, 160℃, 165℃, and 168℃, and the screw speed at 60 rpm. The polypropylene then enters the sheath cavity of the two-component spinning box. Polycaprolactam is placed in the twin-screw extruder, controlling the base temperature at 185℃, 210℃, 225℃, and 225℃, and the screw speed at 60 rpm. This polycaprolactam then enters the core cavity of the two-component spinning box. The mass ratio of sheath to core is controlled at 1:1.3 for spinning. The sheath spinning temperature is 170℃, and the core spinning temperature is 230℃. After side-blowing cooling, drawing, and web formation, a fiber web with a fineness of 1.2 dtex is obtained. The fiber web is then hot-rolled at 145℃ to obtain a basis weight of 20 g / m². 2 Nonwoven fabric.

[0018] Example 2: A bicomponent spunbond nonwoven fabric and its production process A bicomponent spunbond woven fabric is composed of bicomponent fibers with a core-sheath composite structure, wherein the sheath of the bicomponent fibers is a composite polypropylene and the core is polycaprolactam. The preparation method of the composite polypropylene includes polypropylene hydrophilic treatment, starch functional treatment, and a composite step, as detailed below: The hydrophilic treatment step for polypropylene is as follows: 100g of polypropylene is placed in a high-speed mixer, and the stirring speed is controlled at 900rpm. Then, 0.28g of benzoyl peroxide, 1.0g of antioxidant, and 0.18g of ethylene bis-stearamide are added, and the mixture is stirred for 25min. While stirring, 4.0g of polyethylene glycol monoallyl ether is added, and the mixture is stirred for another 13min. Then, another 4.0g of polyethylene glycol monoallyl ether is added to obtain a polypropylene mixture. The polypropylene mixture is then placed in a twin-screw extruder for melt extrusion, and the extrusion temperature is controlled at 153℃, 168℃, 178℃, and 172℃, and the screw speed is 43rpm. After washing and drying, hydrophilic polypropylene is obtained. The polypropylene has a melt flow index of 15 g / 10 min at 230°C and 2.16 kg. The antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1; The number-average molecular weight of the polyethylene glycol monoallyl ether is 1000.

[0019] The starch functionalization process is as follows: 10g of corn starch is placed in 100g of deionized water, 0.2g of Tween 80 is added, and the mixture is stirred evenly. Then, 10wt% sodium hydroxide solution is added to adjust the pH to 9.5, the temperature is raised to 52℃, 1.8mL of sodium hypochlorite is added, and the mixture is stirred for 2.7h. After stirring, 12wt% hydrochloric acid solution is added to adjust the pH to 6.8. After washing and drying, oxidized starch is obtained. 10g of oxidized starch is placed in 100g of deionized water, stirred evenly, and 10wt% sodium hydroxide solution is added to adjust the pH to 10.2. Then, 1.3g of polyethylene glycol diglycidyl ether is added, the temperature is raised to 60℃ at a rate of 1.8℃ / min, and the mixture is kept at 400rpm and stirred for 3.3h. After filtration, washing, and drying, functional starch is obtained. The corn starch has a particle size of 1.5 μm.

[0020] The compounding step is as follows: 10g of functional starch is added to 85g of deionized water, the temperature is raised to 78℃, and after stirring evenly, 0.8g of kH550 silane coupling agent is added, and stirring is continued for 1.7h. After washing and drying, pretreated functional starch is obtained. 4g of pretreated functional starch was added to 50g of deionized water and stirred until homogeneous to obtain a pretreated functional starch solution. 17g of hydrophilic polypropylene was added to 120g of xylene, the temperature was raised to 87℃, and after stirring until homogeneous, it was added to 54g of pretreated functional starch solution at 770rpm. The mixture was ultrasonically dispersed for 28min at an ultrasonic power of 110W and an ultrasonic frequency of 32kHz. After ultrasonic dispersion, the mixture was dried to obtain composite polypropylene.

[0021] A production process for a bicomponent spunbond nonwoven fabric involves placing composite polypropylene in a twin-screw extruder, controlling the extrusion temperature at 148℃, 162℃, 167℃, and 170℃, and the screw speed at 65 rpm. The polypropylene then enters the sheath cavity of the bicomponent spinning box. Polycaprolactam is placed in the twin-screw extruder, controlling the base temperature at 188℃, 213℃, 227℃, and 227℃, and the screw speed at 65 rpm. This polycaprolactam then enters the core cavity of the bicomponent spinning box. The mass ratio of sheath to core is controlled at 1:1.4 for spinning. The sheath spinning temperature is 172℃, and the core spinning temperature is 232℃. After side-blowing cooling, drawing, and web formation, a fiber web with a fineness of 1.3 dtex is obtained. The fiber web is then hot-rolled at 147℃ to obtain a basis weight of 25 g / m². 2 Nonwoven fabric.

[0022] Example 3: A bicomponent spunbond nonwoven fabric and its production process A bicomponent spunbond woven fabric is composed of bicomponent fibers with a core-sheath composite structure, wherein the sheath of the bicomponent fibers is a composite polypropylene and the core is polycaprolactam. The preparation method of the composite polypropylene includes polypropylene hydrophilic treatment, starch functional treatment, and a composite step, as detailed below: The hydrophilic treatment step for polypropylene is as follows: 100g of polypropylene is placed in a high-speed mixer, and the stirring speed is controlled at 1000rpm. Then, 0.30g of benzoyl peroxide, 1.0g of antioxidant, and 0.20g of ethylene bis-stearamide are added, and the mixture is stirred for 25min. While stirring, 4.2g of polyethylene glycol monoallyl ether is added, and the mixture is stirred for another 15min. Then, another 4.2g of polyethylene glycol monoallyl ether is added to obtain a polypropylene mixture. The polypropylene mixture is then placed in a twin-screw extruder for melt extrusion, and the extrusion temperature is controlled at 155℃, 170℃, 180℃, and 172℃, and the screw speed is 45rpm. After washing and drying, hydrophilic polypropylene is obtained. The polypropylene has a melt flow index of 18 g / 10 min at 230°C and 2.16 kg. The antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1; The number-average molecular weight of the polyethylene glycol monoallyl ether is 1100.

[0023] The starch functionalization process is as follows: 10g of corn starch is placed in 100g of deionized water, 0.3g of Tween 80 is added, and the mixture is stirred evenly. Then, 12wt% sodium hydroxide solution is added to adjust the pH to 10, the temperature is raised to 53℃, 2.0mL of sodium hypochlorite is added, and the mixture is stirred for 3.0h. After stirring, 12wt% hydrochloric acid solution is added to adjust the pH to 7.0. After washing and drying, oxidized starch is obtained. 12g of oxidized starch is placed in 110g of deionized water, stirred evenly, and 12wt% sodium hydroxide solution is added to adjust the pH to 10.5. Then, 1.5g of polyethylene glycol diglycidyl ether is added, the temperature is raised to 62℃ at a rate of 2.0℃ / min, and the mixture is kept at 400rpm and stirred for 3.5h. After filtration, washing, and drying, functional starch is obtained. The corn starch has a particle size of 2 μm.

[0024] The compounding step is as follows: 10g of functional starch is added to 90g of deionized water, the temperature is raised to 80℃, and after stirring evenly, 1.0g of kH550 silane coupling agent is added, and stirring is continued for 2.0h. After washing and drying, pretreated functional starch is obtained. Add 5g of pretreated functional starch to 50g of deionized water and stir until homogeneous to obtain a pretreated functional starch solution. Add 20g of hydrophilic polypropylene to 120g of xylene, raise the temperature to 90℃, stir until homogeneous, and then add it to 55g of pretreated functional starch solution at 800rpm. Ultrasonic dispersion is carried out for 330min at an ultrasonic power of 120W and an ultrasonic frequency of 35kHz. After ultrasonic dispersion, the product is dried to obtain composite polypropylene.

[0025] A production process for a bicomponent spunbond nonwoven fabric involves placing composite polypropylene in a twin-screw extruder, controlling the extrusion temperature at 150℃, 165℃, 170℃, and 172℃, and the screw speed at 70 rpm. The polypropylene then enters the sheath cavity of the bicomponent spinning box. Polycaprolactam is placed in the twin-screw extruder, controlling the base temperature at 190℃, 215℃, 230℃, and 230℃, and the screw speed at 70 rpm. This polycaprolactam then enters the core cavity of the bicomponent spinning box. The mass ratio of sheath to core is controlled at 1:1.5 for spinning, with the sheath spinning temperature at 175℃ and the core spinning temperature at 235℃. After side-blowing cooling, drawing, and web formation, a fiber web with a fineness of 1.5 dtex is obtained. The fiber web is then hot-rolled at 150℃ to obtain a basis weight of 23 g / m². 2 Nonwoven fabric.

[0026] Comparative Example 2-1 Based on Example 2, the following changes were made: The hydrophilic treatment step of polypropylene is omitted; in the compounding step, the hydrophilic polypropylene is replaced in equal amounts with untreated polypropylene, wherein the polypropylene has a melt index of 12-18 g / 10 min at 230°C and 2.16 kg. The rest of the operations are exactly the same.

[0027] Comparative Example 2-2 Based on Example 2, the following changes were made: The starch functionalization treatment step is omitted; in the compounding step, the functional starch is replaced in equal amounts with untreated corn starch with a particle size of 1-2 μm. The rest of the operations are exactly the same.

[0028] Performance testing The nonwoven fabrics prepared in Examples 1-3, Comparative Examples 2-1, and Comparative Examples 2-2 were subjected to comprehensive performance tests, as detailed below:

[0029] The chemical resistance test involved immersing the nonwoven fabrics prepared in Examples 1-3, Comparative Examples 2-1, and Comparative Examples 2-2 in a 6-fold weight of 8wt% hydrochloric acid solution for 12 hours, removing and drying them, then immersing them in an 8wt% sodium hydroxide solution for 12 hours, removing and drying them, and then testing their strength properties again.

[0030] Comparative Example 2-1 omitted the hydrophilic treatment of polypropylene, resulting in extremely poor compatibility with functional starch. During spinning, polypropylene and functional starch easily separate in the cortex. When the fiber is under stress, the cortex starch quickly falls off, relying solely on the core layer for load-bearing, which greatly reduces the product's strength and chemical stability. Furthermore, polypropylene has poor water absorption, with a low water absorption rate and a long liquid penetration time, ultimately leading to a significant decrease in the overall performance of the final product. Comparative Example 2-2 omitted the functional treatment of starch, making it impossible to achieve cross-linking with hydrophilic polypropylene, which would reduce the product's strength and stability.

[0031] Unless otherwise specified, all proportions mentioned in this invention are mass proportions, and all percentages are mass percentages.

[0032] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bicomponent spunbond woven fabric, characterized in that, It is composed of bicomponent fibers with a core-sheath composite structure, wherein the sheath of the bicomponent fiber is a composite polypropylene and the core is polycaprolactam; The method for preparing the composite polypropylene includes a polypropylene hydrophilic treatment, a starch functional treatment, and a composite step. The hydrophilic treatment step of polypropylene is as follows: add benzoyl peroxide, antioxidant, and ethylene bis-stearamide to polypropylene, stir for 20-25 minutes, add polyethylene glycol monoallyl ether, stir for 10-15 minutes, add polyethylene glycol monoallyl ether again to obtain polypropylene mixture, and put the polypropylene mixture into a twin-screw extruder for melt extrusion to obtain hydrophilic polypropylene. The starch functionalization process involves placing corn starch in deionized water, adding Tween 80, stirring until homogeneous, adding sodium hydroxide solution to adjust the pH to 9-10, raising the temperature to 50-53℃, adding sodium hypochlorite, stirring for 2.5-3.0 hours, adding hydrochloric acid solution to adjust the pH to 6.5-7.0, and obtaining oxidized starch. The oxidized starch is then placed in deionized water, sodium hydroxide solution is added to adjust the pH to 10.0-10.5, polyethylene glycol diglycidyl ether is added, and the temperature is raised to 58-62℃ at a rate of 1.5-2.0℃ / min, and stirred at 380-400 rpm for 3.0-3.5 hours to obtain functional starch.

2. The bicomponent spunbond woven fabric according to claim 1, characterized in that, In the polypropylene hydrophilic treatment step, the polypropylene has a melt index of 12-18 g / 10 min at 230℃ and 2.16 kg. The antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1-2; The number-average molecular weight of the polyethylene glycol monoallyl ether is 900-1100.

3. The bicomponent spunbond woven fabric according to claim 1, characterized in that, In the polypropylene hydrophilic treatment step, the mass ratio of the polypropylene, benzoyl peroxide, antioxidant, ethylene bis-stearamide, polyethylene glycol monoallyl ether added once, and polyethylene glycol monoallyl ether added twice is 100:0.25-0.30:0.8-1.0:0.15-0.20:3.8-4.2:3.8-4.

2.

4. The bicomponent spunbond woven fabric according to claim 1, characterized in that, In the starch functional treatment step, the particle size of the corn starch is 1-2 μm; The mass-to-volume ratio of corn starch, deionized water, Tween 80, and sodium hypochlorite is 10g:80-100g:0.2-0.3g:1.5-2.0mL; The mass ratio of oxidized starch, deionized water, and polyethylene glycol diglycidyl ether is 10-12:100-110:1.2-1.

5.

5. The bicomponent spunbond woven fabric according to claim 1, characterized in that, The compounding steps are as follows: Functional starch is added to deionized water, the temperature is raised to 75-80℃, and after stirring evenly, kH550 silane coupling agent is added, and stirring is continued for 1.5-2.0 hours. After washing and drying, pretreated functional starch is obtained. The pretreated functional starch is then added to deionized water and stirred evenly to obtain a pretreated functional starch solution. Hydrophilic polypropylene is added to xylene, the temperature is raised to 85-90℃, and after stirring evenly, it is added to the pretreated functional starch solution at 750-800 rpm. The solution is then ultrasonically dispersed for 25-30 minutes at an ultrasonic power of 100-120W and an ultrasonic frequency of 30-35kHz. After ultrasonic dispersion, the solution is dried to obtain composite polypropylene.

6. The bicomponent spunbond woven fabric according to claim 5, characterized in that, In the pretreated functional starch, the mass ratio of functional starch, deionized water, and kH550 silane coupling agent is 10:80-90:0.8-1.

0. In the pretreated functional starch solution, the mass ratio of pretreated functional starch to deionized water is 3-5:

50. The mass ratio of the hydrophilic polypropylene, xylene, and pretreated functional starch solution is 15-20:120:53-55.

7. The production process of bicomponent spunbond woven fabric according to any one of claims 1-6, characterized in that, The composite polypropylene is placed in a twin-screw extruder, with extrusion temperatures controlled at 145-150℃, 160-165℃, 165-170℃, and 168-172℃, and screw speed at 60-70 rpm. Then, it enters the sheath cavity of the two-component spinning box. Polycaprolactam is placed in the twin-screw extruder, with base temperatures controlled at 185-190℃, 210-215℃, 225-230℃, and 225-230℃, and screw speed at 60-70 rpm. The yarn is spun at 0-70 rpm and then enters the core cavity of the two-component spinning box. The mass ratio of the sheath to the core is controlled at 1:1.3-1.5 for spinning. The sheath spinning temperature is 170-175℃, and the core spinning temperature is 230-235℃. After side-blowing cooling, drawing, and web laying, a fiber web with a fineness of 1.2-1.5 dtex is obtained. The fiber web is then hot-rolled at a temperature of 145-150℃ to obtain a basis weight of 20-25 g / m². 2 Nonwoven fabric.

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