A bicomponent flexible spunbond nonwoven material and method of making the same

Abstract

This invention provides a two-component flexible spunbond nonwoven material and its preparation method. The two-component flexible spunbond nonwoven material consists of a skin layer and a core layer. The skin layer is a PA6 composite material, and the core layer is PBT. Anti-yellowing masterbatch and matte white are also added to the skin layer. Melt spinning, cooling stretching, web laying, and low-temperature hot rolling reinforcement are achieved through a single-screw composite spinning device. The prepared spunbond nonwoven fabric has reduced softness and significantly improved abrasion resistance. It does not yellow under high temperature and long-term use, and is suitable for medical and health, household cleaning, outdoor and industrial packaging and other fields.

Description

Technical Field

[0001] This invention relates to the field of spunbond nonwoven technology, specifically to a two-component flexible spunbond nonwoven material and its preparation method. Background Technology

[0002] Spunbond nonwoven fabrics, a type of nonwoven material prepared through processes such as polymer melt spinning, drawing, web laying, and reinforcement, are widely used in industries such as medical and health care and personal care due to their high production efficiency and diverse properties. For example, spunbond nonwoven fabrics play important roles in products such as medical protective clothing and baby diapers, providing protection, isolation, and absorption. However, existing spunbond nonwoven fabric technology still has significant shortcomings.

[0003] In terms of flexibility, traditional spunbond nonwovens primarily use rigid polymers such as polypropylene (PP) and polyester (PET) as raw materials. Their high molecular chain regularity and crystallinity result in poor material softness. When the fiber diameter is large, the material's bending stiffness increases exponentially with the fiber diameter, easily causing discomfort upon contact with human skin and failing to meet the stringent requirements for soft touch in high-end medical dressings and intimate care products. Furthermore, single polymer systems are prone to stress concentration during stretching and folding, leading to insufficient material flexibility and susceptibility to damage under repeated use, shortening their lifespan. Regarding manufacturing processes, existing technologies often employ methods such as adding plasticizers, blending with low-melting-point polymers, or post-treatment coatings to improve the flexibility of spunbond nonwovens. However, these processes not only increase raw material costs but also easily cause clogging of spinning components, reducing production stability. The additional coating process requires specialized equipment, further increasing production costs and leading to a 15%–30% increase in overall product cost. Furthermore, the complex multi-stage temperature control and high-precision drafting process parameters place extremely high demands on equipment accuracy and operator skill levels, making the production process difficult to control and hindering the advancement of large-scale industrial production. Traditional spunbond nonwovens also have shortcomings in their anti-yellowing properties. During storage and use, they are prone to oxidative yellowing due to environmental factors such as light and temperature, affecting product appearance and quality. This is particularly problematic in high-end hygiene materials and outdoor protective equipment where color stability is critical, severely limiting their application. Therefore, developing a spunbond nonwoven material that combines excellent flexibility, abrasion resistance, and anti-yellowing properties with low manufacturing costs and a simple manufacturing process is of significant practical importance.

[0004] In view of the problems existing in the prior art, how to provide a flexible spunbond nonwoven fabric that solves the problems of insufficient flexibility, poor abrasion resistance and weak anti-yellowing performance of existing spunbond nonwoven fabrics, as well as high preparation cost and complex preparation process, is the problem that this invention urgently needs to solve. Summary of the Invention

[0005] Purpose of the invention:

[0006] The present invention aims to provide a two-component flexible spunbond nonwoven material and its preparation method, which solves the problems of insufficient flexibility, poor abrasion resistance and weak anti-yellowing performance of existing spunbond nonwoven fabrics, as well as high preparation cost and complex preparation process.

[0007] The technical solution of this invention:

[0008] A two-component flexible spunbond nonwoven material, comprising a skin layer and a core layer; the skin layer is PA6 composite material, and the core layer is PBT; the skin layer also contains anti-yellowing masterbatch and matte white.

[0009] Furthermore, the mass ratio of the PA6 composite material to PBT is 2:8 to 8:2.

[0010] In this application, PA6 refers to Wenzhou Huajian Nylon 6 chips, which serve as the core raw material for the outer layer. Its molecular chain is rich in amide groups (-CONH-), and the molecules form moderate intermolecular forces through hydrogen bonds, endowing the outer layer with excellent flexibility and toughness. During the spinning process, the chips exhibit stable fluidity after melting at 240–260°C, enabling them to uniformly coat the core layer PBT. The low bending stiffness of the outer layer reduces the overall softness of the material, while its molecular chain toughness disperses frictional stress, improving the material's basic wear resistance.

[0011] In this application, PBT of the 211S type from Chang Chun Chemical Co., Ltd. in Taiwan is used as the core material. The molecular chain contains a rigid aromatic ring structure, with high crystallinity and excellent thermal stability (melting temperature of about 225-235°C). In the core-sheath structure, its rigid skeleton provides strong support for the fiber, balances the flexibility of the PA6 sheath, and prevents the material from deforming due to excessive flexibility. At the same time, this type of PBT has good stability when melt-spun at 240-270°C and has a tight interface with the PA6 sheath, ensuring that the core-sheath structure works together to bear the force, thereby improving the overall mechanical strength and dimensional stability of the material.

[0012] Furthermore, the mass ratio of the PA6 composite material to PBT is preferably 4:6 to 6:4.

[0013] Furthermore, the preparation of the PA6 composite material includes the following steps:

[0014] S1: Dry PA6 and calcium chloride at 90-100℃ for 6-8 hours. Add PA6 and calcium chloride to a high-speed mixer according to the ratio and mix for 5-10 minutes.

[0015] S2: Then add N-butylbenzenesulfonamide according to the mass ratio, and granulate by co-extrusion in an extruder. The extruder temperature is 220-240℃ and the die temperature is 220℃.

[0016] S3: After the extruded granules are dried at 80℃ for 4 hours, they are injection molded into standard test strips using an injection molding machine. The injection temperature is 220-240℃, the injection pressure is 45-50MPa, the holding time is 30-45min, and then the strips are kept at 25℃ for 24-36 hours to obtain PA6 composite material.

[0017] Furthermore, the amount of N-butylbenzenesulfonamide added is 10-20% of the mass of the mixture of PA6 and calcium chloride.

[0018] Furthermore, the amount of the anti-yellowing masterbatch added is 1-2% of the skin layer mass.

[0019] In this application, the anti-yellowing masterbatch works by combining antioxidants and ultraviolet absorbers. The antioxidants can capture free radicals generated during the oxidation of PA6 and terminate the chain growth reaction; the ultraviolet absorbers selectively absorb ultraviolet light in the range of 290-400nm, reducing the damage of photo-oxidation to the skin layer; the anti-yellowing masterbatch uses PA6 as a carrier, with an addition amount of 1%-2%, and has excellent compatibility with the PA6 skin layer. It can be uniformly dispersed and directionally protect the skin layer interface exposed to the environment, significantly improving the anti-yellowing performance of the material under high temperature and light exposure, and ensuring long-term color stability.

[0020] Furthermore, the amount of the matte white added is 1-5% of the skin mass.

[0021] In this application, the main component of the matte white is titanium dioxide microparticles, whose particle size is adapted to the wavelength of visible light. Through the light scattering mechanism, it destroys the specular reflection of the PA6 skin layer, effectively reducing the gloss of the material surface and making the appearance softer and more natural. The titanium dioxide and other microparticles have high hiding power, covering up the slight yellow undertone that may exist in PA6 or PBT itself, while making the material color more uniform. The amount of matte white added is 1% to 5% of the skin layer mass, and through surface treatment, it has good compatibility with PA6 melt and will not significantly affect the core properties of PA6 such as flexibility and wear resistance, achieving the effect of "optimizing appearance without sacrificing function".

[0022] This invention provides a method for preparing a two-component flexible spunbond nonwoven material, comprising the following steps:

[0023] S1: Melt spinning: A single-screw composite spinning equipment is used. PA6 is added to screw A and melted at 240-270℃; PBT is added to screw B and melted at 230-270℃. The flow rates of the two melts are then controlled by independent metering pumps and fed into the core-sheath composite spinning assembly. The core-sheath structure fibers are extruded through a spinneret. The spinneret orifice diameter is 0.3-0.5μm and the number of orifices is 12000-12200. Screw A is 120-130mm long, rotates at 70-80rpm, and has an aspect ratio of 25-30:1. Screw B is 115-125mm long, rotates at 60-70rpm, and has an aspect ratio of 25-30:1.

[0024] S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 13-20°C and a gas flow rate of 55-60 cm; the cooled fibers are then drawn under positive pressure at a height of 70-75 cm, a slit width of 5-8 mm, and a drawing air pressure of 0.1-0.3 MPa.

[0025] S3: Hot rolling reinforcement: After the fiber is drawn and laid into a web, it is hot rolled for reinforcement. The hot rolling temperature is 190-220℃, the pressure is 3-6MPa, and the rolling mill action time is 0.05-0.1s, to obtain the bicomponent core-sheath structure flexible spunbond nonwoven material.

[0026] Furthermore, the melting temperature of the A screw is 245–255°C, and the melting temperature of the B screw is 250–265°C.

[0027] Furthermore, the spinneret has an orifice diameter of 0.4–0.5 μm and a number of orifices of 12,000–12,119; the A screw has a length of 130–135 mm, a rotation speed of 70–75 rpm, and a length-to-diameter ratio of 28–30:1; the B screw has a length of 120–125 mm, a rotation speed of 60–70 rpm, and a length-to-diameter ratio of 27–30:1.

[0028] Furthermore, the side-blowing air temperature is 14–19°C, and the gas flow rate is 55–58 cm / min.

[0029] Furthermore, the hot rolling temperature is 190–220°C, the pressure is 5–6 MPa, and the action time is 0.06–0.08 s.

[0030] This invention provides a flexible spunbond nonwoven fabric based on a PA6 / PBT bicomponent core-sheath structure. Through innovative material combination and core-sheath structure, it utilizes the excellent flexibility of PA6 and the stable structural support of PBT to reduce the bending stiffness of the nonwoven fabric, enhance its softness, overcome the limitations of material flexibility, and improve the product's tactile comfort and durability. By optimizing the material ratio and preparation process of PA6 / PBT and anti-yellowing masterbatch, it directionally protects the skin interface exposed to the environment, significantly improving the material's anti-yellowing performance under high temperature and light exposure, ensuring long-term color stability. The matte white coating has good compatibility with PA6 melt through surface treatment, without affecting the core properties of PA6 such as flexibility and abrasion resistance, achieving the effect of "appearance optimization without sacrificing function". This invention achieves comprehensive optimization of material flexibility, abrasion resistance, anti-yellowing performance, and appearance quality by selecting substrates and additives with matching characteristics and utilizing the synergistic molecular structure characteristics and mechanisms of action of each component. By optimizing spinning components and process parameters, and replacing the traditional high-temperature and high-pressure hot rolling process with low-temperature hot rolling reinforcement, single-screw composite spinning equipment and low-temperature hot rolling reinforcement processes, the operation process is simplified, the process difficulty is reduced, the production stability and efficiency are improved, raw material waste, equipment maintenance costs and energy consumption are reduced, and process parameter control is simplified, so as to reduce the overall production cost and realize large-scale industrial production.

[0031] Beneficial effects:

[0032] 1. Excellent flexibility and feel: The nonwoven material of this invention adds plasticizers and reinforcing agents to PA6. The PA6 composite material serves as the skin material. With the low glass transition temperature and unique molecular structure of PA6, the nonwoven fabric is endowed with excellent softness.

[0033] 2. Significantly Improved Abrasion Resistance: The amide groups in the PA6 molecular chain provide excellent toughness and surface friction resistance. Combined with the rigid support of the PBT core layer, this significantly improves the abrasion resistance of the nonwoven fabric. The product of this invention was heated at room temperature and 80°C for 2 hours, respectively, and then subjected to a Martindale abrasion test with a weight pressure of 9 kPa. After 1000 abrasion cycles, the fabric surface showed virtually no pilling, fuzzing, or loose threads.

[0034] 3. Excellent anti-yellowing properties: Through precise control of the PA6 / PBT ratio and the addition of anti-yellowing masterbatch, combined with optimized single-screw composite spinning process parameters, the oxidative degradation of the material under conditions such as high temperature and light exposure is effectively inhibited. According to the internal testing standards of Jingfa, the nonwoven fabric of this invention does not yellow under high temperature testing and maintains stable color during long-term storage and use, meeting the stringent appearance quality requirements of high-end hygiene materials and outdoor protective equipment. Attached Figure Description

[0035] Figure 1 Example 1: Front abrasion resistance test results;

[0036] Figure 2 Example 1: Abrasion resistance test results on the reverse side;

[0037] Figure 3 Example 2: Front abrasion resistance test results;

[0038] Figure 4 Example 2: Abrasion resistance test results on the reverse side;

[0039] Figure 5 Example 3: Front abrasion resistance test results;

[0040] Figure 6 Example 4: Abrasion resistance test results on the reverse side. Detailed implementation method:

[0041] The present invention will be described below with reference to specific implementation schemes. It should be noted that the experimental examples below are illustrative of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0042] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade. PA6 is Wenzhou Huajian Nylon 6 chips, and PBT is Taiwan Changchun Chemical 211S.

[0043] The matte white used in the following experimental examples is Nantong Yiheng CR90FS; the anti-yellowing masterbatch is Ruidao Chemical RY203.

[0044] Preparation of PA6 composite materials:

[0045] S1: Dry PA6 and calcium chloride (PA6 to calcium chloride mass ratio 94:6) at 100℃ for 6 hours. Add PA6 and calcium chloride to a high-speed mixer according to the ratio and mix for 5 minutes.

[0046] S2: Then, N-butylbenzenesulfonamide (20%) is added according to the mass ratio, and granulation is carried out by extrusion in an extruder. The extruder temperature is 240℃ and the die temperature is 220℃.

[0047] S3: After the extruded granules are dried at 80℃ for 4 hours, they are injection molded into standard specimens using an injection molding machine. The injection temperature is 240℃, the injection pressure is 45MPa, the holding time is 30min, and then the temperature is maintained at 25℃ for 24 hours to obtain PA6 composite material.

[0048] Preparation of anti-yellowing masterbatch:

[0049] The anti-yellowing masterbatch Ruidao Chemical RY203, titanium dioxide masterbatch, antioxidant 1010, and ultraviolet absorber uv-329 were mixed evenly in a mass ratio of 10:5:1:1.

[0050] Example 1

[0051] 1. Material composition: The mass ratio of PA6 composite material to PBT is 4:6, containing 1.5% anti-yellowing masterbatch by mass of PA6 composite material and 3% matte white by mass of PA6 composite material;

[0052] 2. Preparation process:

[0053] S1: Melt spinning: A single-screw composite spinning equipment is used. PA6 composite material, anti-yellowing masterbatch, and matte white are added to screw A and melted at 255℃; PBT is added to screw B and melted at 250℃. The flow rates of the two melts are then controlled by independent metering pumps and fed into the core-sheath composite spinning assembly. The core-sheath structure fibers are formed by extrusion through a spinneret. The spinneret has an orifice diameter of 0.4μm and a number of orifices of 12119. Screw A is 130mm long, rotates at 75rpm, and has an aspect ratio of 30:1. Screw B is 120mm long, rotates at 60rpm, and has an aspect ratio of 27:1.

[0054] S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 14.7℃ and a gas flow rate of 58 CMM; the cooled fibers are then drawn under positive pressure with a drawing height of 70 cm, a drawing slit of 6 mm, and a drawing air pressure of 0.2 MPa.

[0055] S3: Hot Rolling Reinforcement: After fiber stretching and web laying, hot rolling reinforcement is performed at a temperature of 210℃, a pressure of 5MPa, and a rolling mill action time of 0.08s, yielding a basis weight of 40g / m². 2 A two-component, core-skin structure flexible spunbond nonwoven material;

[0056] The nonwoven fabric was heated at room temperature and 80°C for 2 hours respectively, and then subjected to Martindale abrasion resistance test with a weight pressure of 9 kPa. After 1000 abrasion cycles, the fabric surface showed slight pilling and loose threads, indicating excellent abrasion resistance.

[0057] Example 2

[0058] 1. Material composition: The mass ratio of PA6 composite material to PBT is 5:5, containing 1% anti-yellowing masterbatch of PA6 composite material and 2% matte white of PA6 composite material by mass;

[0059] 2. Preparation process:

[0060] S1: Melt spinning: A single-screw composite spinning equipment is used. PA6 composite material, anti-yellowing masterbatch, and matte white are added to screw A and melted at 255℃; PBT is added to screw B and melted at 250℃. The flow rates of the two melts are then controlled by independent metering pumps and fed into the core-sheath composite spinning assembly. The core-sheath structure fibers are formed by extrusion through a spinneret. The spinneret has an orifice diameter of 0.4μm and a number of orifices of 12119. Screw A is 130mm long, rotates at 75rpm, and has an aspect ratio of 30:1. Screw B is 120mm long, rotates at 60rpm, and has an aspect ratio of 27:1.

[0061] S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 15.8℃ and a gas flow rate of 58 CMM; the cooled fibers are then drawn under positive pressure with a drawing height of 70 cm, a drawing slit of 6 mm, and a drawing air pressure of 0.2 MPa.

[0062] S3: Hot Rolling Reinforcement: After fiber stretching and web laying, hot rolling reinforcement is performed at a temperature of 190℃, a pressure of 5MPa, and a rolling mill action time of 0.08s, yielding a basis weight of 40g / m². 2 A two-component, core-skin structure flexible spunbond nonwoven material;

[0063] The nonwoven fabric was heated at room temperature and 80°C for 2 hours respectively, and then subjected to Martindale abrasion test with a weight pressure of 9 kPa. After 1000 abrasion cycles, the fabric surface showed slight pilling and loose threads, indicating excellent abrasion resistance.

[0064] Example 3

[0065] 1. Material composition: The mass ratio of PA6 composite material to PBT is 6:4, containing 2% anti-yellowing masterbatch by mass of PA6 composite material and 4% matte white by mass of PA6 composite material;

[0066] 2. Preparation process:

[0067] S1: Melt spinning: A single-screw composite spinning equipment is used. PA6 composite material, anti-yellowing masterbatch, and matte white are added to screw A and melted at 257.5℃; PBT is added to screw B and melted at 260℃. The flow rates of the two melts are then controlled by independent metering pumps and fed into the core-sheath composite spinning assembly. The core-sheath structure fibers are formed by extrusion through a spinneret. The spinneret has a pore size of 0.4μm and a pore count of 12119. Screw A is 130mm long, rotates at 75rpm, and has an aspect ratio of 30:1. Screw B is 120mm long, rotates at 60rpm, and has an aspect ratio of 27:1.

[0068] S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 18.4℃ and a gas flow rate of 58 CMM; the cooled fibers are then drawn under positive pressure with a drawing height of 70cm, a drawing slit of 6mm, and a drawing air pressure of 0.2MPa.

[0069] S3: Hot Rolling Reinforcement: After fiber stretching and web laying, hot rolling reinforcement is performed at a temperature of 220℃, a pressure of 5MPa, and a rolling mill action time of 0.08s, yielding a basis weight of 40g / m². 2 A two-component, core-skin structure flexible spunbond nonwoven material;

[0070] The nonwoven fabric was heated at room temperature and 80°C for 2 hours respectively, and then subjected to Martindale abrasion resistance test with a weight pressure of 9 kPa. After 1000 abrasion cycles, the fabric surface showed virtually no pilling, fuzzing, or loose threads, indicating excellent abrasion resistance.

[0071] Comparative Example 1

[0072] 1. Material composition: 100% polypropylene (PP), without anti-yellowing masterbatch and matte white;

[0073] 2. Preparation process:

[0074] S1: Melt spinning: A single-screw composite spinning device is used. PP is added to the screw and melted at 220℃. Then it is extruded through a spinneret with a spinneret orifice diameter of 0.4μm and a number of orifices of 12119. Screw A is 130mm long, rotates at 75rpm, and has an aspect ratio of 30:1. Screw B is 120mm long, rotates at 60rpm, and has an aspect ratio of 27:1.

[0075] S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 22.6℃ and a gas flow rate of 50 CMM; the cooled fibers are then drawn under positive pressure with a drawing height of 70 cm, a drawing slit of 6 mm, and a drawing air pressure of 0.2 MPa.

[0076] S3: Hot Rolling Reinforcement: After fiber stretching and web laying, hot rolling reinforcement is performed at a temperature of 220℃, a pressure of 5MPa, and a rolling mill action time of 0.08s, yielding a basis weight of 40g / m². 2 spunbond nonwoven materials;

[0077] The nonwoven fabric was heated at room temperature and 80°C for 2 hours respectively, and then subjected to Martindale abrasion resistance test with a weight pressure of 9 kPa. After 1000 abrasion cycles, the fabric surface showed severe pilling and large areas of loose fibers, indicating poor abrasion resistance.

[0078] Comparative Example 2

[0079] 1. Material composition: The mass ratio of PA6 composite material to PBT is 5:5, containing 1.5% anti-yellowing masterbatch by mass of PA6 composite material and 3% matte white by mass of PA6 composite material;

[0080] 2. Preparation process:

[0081] S1: Melt spinning: Using a single-screw spinning machine, PA6 composite material, anti-yellowing masterbatch, and matte white are blended with PBT and melted at 280℃, then extruded through a spinneret with a 0.4μm orifice diameter and 12119 orifices. Screw A is 130mm long, rotates at 75rpm, and has an aspect ratio of 30:1. Screw B is 120mm long, rotates at 60rpm, and has an aspect ratio of 27:1.

[0082] S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 15.8℃ and a gas flow rate of 58 CMM; the cooled fibers are then drawn under positive pressure with a drawing height of 70 cm, a drawing slit of 6 mm, and a drawing air pressure of 0.2 MPa.

[0083] S3: Hot Rolling Reinforcement: After fiber stretching and web laying, hot rolling reinforcement is performed at a temperature of 220℃, a pressure of 5MPa, and a rolling mill action time of 0.08s, yielding a basis weight of 40g / m². 2 A two-component, core-skin structure flexible spunbond nonwoven material;

[0084] The nonwoven fabric was heated at room temperature and 80°C for 2 hours respectively, and then subjected to Martindale abrasion test with a weight pressure of 9 kPa. After 1000 abrasion cycles, the fabric showed increased pilling and fuzzing, severe breakage of floating threads, and poor abrasion resistance.

[0085] Comparative Example 3

[0086] 1. Material composition: The mass ratio of PA6 composite material to PBT is 9:1, containing 1.5% anti-yellowing masterbatch by mass of PA6 composite material and 3% matte white by mass of PA6 composite material;

[0087] 2. Preparation process:

[0088] S1: Melt spinning: A single-screw composite spinning equipment is used. PA6 composite material, anti-yellowing masterbatch, and matte white are added to screw A and melted at 257.5℃; PBT is added to screw B and melted at 260℃. The flow rates of the two melts are then controlled by independent metering pumps and fed into the core-sheath composite spinning assembly. The core-sheath structure fibers are formed by extrusion through a spinneret. The spinneret has a pore size of 0.4μm and a pore count of 12119. Screw A is 130mm long, rotates at 75rpm, and has an aspect ratio of 30:1. Screw B is 120mm long, rotates at 60rpm, and has an aspect ratio of 27:1.

[0089] S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 18.4℃ and a gas flow rate of 58 CMM; the cooled fibers are then drawn under positive pressure with a drawing height of 70cm, a drawing slit of 6mm, and a drawing air pressure of 0.2MPa.

[0090] S3: Hot Rolling Reinforcement: After fiber stretching and web laying, hot rolling reinforcement is performed at a temperature of 220℃, a pressure of 5MPa, and a rolling mill action time of 0.08s, yielding a basis weight of 40g / m². 2 A two-component, core-skin structure flexible spunbond nonwoven material;

[0091] The nonwoven fabric was heated at room temperature and 80°C for 2 hours respectively, and then subjected to Martindale abrasion test with a weight pressure of 9 kPa. After 1000 abrasion cycles, the fabric showed slight pilling and fuzzing, indicating excellent abrasion resistance.

[0092] Performance testing:

[0093] 1. Conduct mechanical property tests such as transverse breaking strength, elongation at break, longitudinal breaking strength, and elongation at break according to the ASTM D5035 test standard.

[0094] 2. The air permeability performance was tested according to the GB / T 5453 test standard, using a fabric air permeability meter with the pressure difference set to 100 Pa.

[0095] 3. Perform the softness test according to the EDANA WSP 90.3 test standard. Use a probe to press the sample vertically downwards, set the probe descent speed to 10 mm / s and the descent distance to 8 mm, and record the resistance encountered by the probe when it penetrates 8 mm of the sample, in g.

[0096] 4. Conduct anti-yellowing tests according to GB / T 30669-2014 test standard; set the test conditions with an irradiance of 0.71 W / m². 2 (340nm), the temperature inside the chamber is 40±3℃, the relative humidity is 50±5%, the irradiation time is 168h. After the test, the sample is taken out of the test chamber and placed in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for at least 4h. The irradiated sample is compared with the unirradiated control sample. The yellowing level of the sample is evaluated using a gray scale. The level is divided into 1 to 5, where level 5 indicates no yellowing and level 1 indicates the most severe yellowing.

[0097] Table 1: Performance Test Results

[0098]

[0099]

[0100] The test results show that the bicomponent flexible spunbond nonwoven material of the present invention has good softness, abrasion resistance, and no yellowing under high temperature and long-term use. Specifically, compared with Comparative Example 1, Experimental Example 1 shows that when polypropylene is selected as a single material, the prepared spunbond nonwoven material has poorer flexibility, poorer anti-yellowing performance, and poorer abrasion resistance, failing to meet the expected requirements. Compared with Comparative Example 2, Experimental Example 2 shows that the structure of the spunbond nonwoven material prepared by blending in Comparative Example 2 cannot achieve the precise synergy between the flexibility of PA6 composite material and the rigidity of PBT as in the core-sheath structure. Uneven distribution of molecular chains leads to stress concentration and decreased mechanical properties, failing to meet the expected requirements. Compared with Comparative Example 3, Experimental Examples 1-3 show that although the increased proportion of PA6 composite material brings better softness and breathability, the insufficient proportion of PBT core layer significantly reduces longitudinal breaking strength and weakens high-temperature abrasion resistance, thus failing to meet the expected requirements. Therefore, Comparative Example 1 verifies the performance advantages of the two-component core-sheath structure compared with traditional single polymer materials; Comparative Example 2, the blend structure, proves the irreplaceable nature of the core-sheath structure in terms of performance synergy; and Comparative Example 3 verifies the rationality of the PA6 composite material / PBT mass ratio.

[0101] This invention can also be demonstrated through various other experimental examples. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A two-component flexible spunbond nonwoven material, characterized in that, The bicomponent flexible spunbond nonwoven material consists of a skin layer and a core layer; the skin layer is PA6 composite material, and the core layer is PBT; anti-yellowing masterbatch and matte white are also added to the skin layer; The preparation of the PA6 composite material includes the following steps: S1: Dry PA6 and calcium chloride at 90-100℃ for 6-8 hours. Add PA6 and calcium chloride to a high-speed mixer according to the ratio and mix for 5-10 minutes. S2: Then add N-butylbenzenesulfonamide according to the mass ratio, and granulate by co-extrusion in an extruder. The extruder temperature is 220~240℃ and the die temperature is 220℃. S3: After the extruded granules are dried at 80℃ for 4 hours, they are injection molded into standard test strips using an injection molding machine. The injection temperature is 220~240℃, the injection pressure is 45-50MPa, the holding time is 30-45min, and then the temperature is maintained at 25℃ for 24-36 hours to obtain PA6 composite material. The amount of N-butylbenzenesulfonamide added is 10-20% of the mass of the mixture of PA6 and calcium chloride.

2. The bicomponent flexible spunbond nonwoven material according to claim 1, characterized in that, The mass ratio of PA6 composite material to PBT is 2:8 to 8:

2.

3. The bicomponent flexible spunbond nonwoven material according to claim 1, characterized in that, The mass ratio of PA6 composite material to PBT is 4:6 to 6:

4.

4. The bicomponent flexible spunbond nonwoven material according to claim 1, characterized in that, The amount of anti-yellowing masterbatch added is 1-2% of the skin layer mass; the anti-yellowing masterbatch is a mixture of anti-yellowing masterbatch RY203, titanium dioxide masterbatch, antioxidant 1010, and ultraviolet absorber uv-329.

5. The bicomponent flexible spunbond nonwoven material according to claim 1, characterized in that, The amount of matte white added is 1-5% of the skin mass.

6. A method for preparing a bicomponent flexible spunbond nonwoven material according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Melt spinning: A single-screw composite spinning equipment is used. PA6 composite material is added to screw A and melted at 240~270℃; PBT is added to screw B and melted at 230~270℃. The flow rates of the two melts are then controlled by independent metering pumps and enter the core-sheath composite spinning assembly. The core-sheath structure fibers are formed by extrusion through a spinneret. The spinneret orifice diameter is 0.3~0.5μm and the number of orifices is 12000~13000. Screw A is 120~135mm long, rotates at 70~80rpm, and has an aspect ratio of 25~30:

1. Screw B is 115~125mm long, rotates at 60~70rpm, and has an aspect ratio of 25~30:

1. S2: Cooling and drawing: The extruded fibers are cooled by side blowing air at a temperature of 13~20℃ and a gas flow rate of 55~60 CMM; the cooled fibers are then drawn under positive pressure with a drawing height of 70~75cm, a drawing slit of 5~8mm, and a drawing air pressure of 0.1~0.3MPa. S3: Hot rolling reinforcement: After the fiber is drawn and laid into a web, it is hot rolled for reinforcement. The hot rolling temperature is 190~220℃, the pressure is 3~6MPa, and the rolling mill action time is 0.05~0.1s, to obtain the bicomponent core-sheath structure flexible spunbond nonwoven material.

7. The method for preparing the bicomponent flexible spunbond nonwoven material according to claim 6, characterized in that, The melting temperature of screw A is 245~255℃, and the melting temperature of screw B is 250~265℃.

8. The method for preparing the bicomponent flexible spunbond nonwoven material according to claim 6, characterized in that, The spinneret has an orifice diameter of 0.4~0.5μm and a number of orifices of 12000~12119; the A screw has a length of 130~135mm, a rotation speed of 70~75rpm, and a length-to-diameter ratio of 28~30:1; the B screw has a length of 120~125mm, a rotation speed of 60~70rpm, and a length-to-diameter ratio of 27~30:

1.

9. The method for preparing the bicomponent flexible spunbond nonwoven material according to claim 6, characterized in that, The side-blowing air temperature is 14~19℃, and the gas flow rate is 55-58 cm / mm.

10. The method for preparing the bicomponent flexible spunbond nonwoven material according to claim 6, characterized in that, The hot rolling temperature is 190~220℃, the pressure is 5~6MPa, and the action time is 0.06~0.08s.

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