Pbat melt-blown nonwoven fabric and melt-blown air flow field preparation method thereof

Abstract

The present application relates to a kind of PBAT melt-blown nonwoven fabric and its melt-blown air flow field preparation method, preparation method: PBAT master batch is prepared by melt-blown process to obtain PBAT melt-blown nonwoven fabric;In melt-blown process, the temperature of draft airflow is 25~65 ℃, the distance between spinneret and receiving net system is 40~70 cm;The melting point of PBAT master batch is above 120 ℃, and the thermal decomposition temperature is above 200 ℃;The elongation at break of the PBAT melt-blown nonwoven fabric prepared is 160~180%.The present application is a kind of method for preparing PBAT melt-blown nonwoven fabric by melt-blown air flow field, the crystallization performance of PBAT is improved by regulating melt-blown air flow field parameters;The present application is a kind of PBAT melt-blown nonwoven fabric prepared by melt-blown air flow field, has better toughness, because it has excellent toughness, it has the advantages such as moderate tightness, good stretch, soft hand feeling, good air permeability, no tight compression feeling.

Description

Technical Field

[0001] This invention belongs to the field of meltblown nonwoven fabric technology, and relates to a PBAT meltblown nonwoven fabric and a method for preparing the meltblown air flow field. Background Technology

[0002] Faced with increasingly serious plastic pollution, especially the surge in single-use plastic waste, which has impacted the ecological environment and human health, biodegradable materials have become a hot development area. Biodegradable plastics are gradually replacing traditional non-biodegradable plastics, and the demand for biodegradable plastics continues to rise. Currently, meltblown biodegradable raw materials include PLA, TPU, and PCL, which are widely used in daily necessities, textiles, and medical and health fields due to their excellent material properties. Polybutylene adipate terephthalate (PBAT) is a biodegradable thermoplastic and an eco-friendly alternative to traditional non-biodegradable plastics. It can be produced using a process dominated by stretch polymer melt flow, exhibiting good film-forming properties. PBAT is often used as an auxiliary material in blending and modification with PLA or other biodegradable materials to produce biodegradable products such as shopping bags, express delivery bags, agricultural films, lunch boxes, tableware, cutlery, and straws.

[0003] As research progresses, the overall performance of PBAT products will continue to improve, while their price will significantly decrease, gradually leading to their replacement of traditional plastics. Compared to other biodegradable plastics, PBAT can degrade in soil without temperature control and also in water. Other biodegradable plastics cannot do this; for example, PLA can only biodegrade into carbon dioxide and water under composting conditions. Therefore, developing the broad application prospects and potential of PBAT is a significant challenge.

[0004] Meltblowing is a spinning method that uses a high-speed hot airflow (above 200°C) to rapidly stretch and solidify freshly extruded polymer melt into shape. However, PBAT has poor heat resistance and is difficult to solidify in the high-speed hot airflow of a meltblowing system.

[0005] To address the aforementioned issues, CN105586712A and CN113861644A modify PBAT through blending by adding polymers with high heat resistance and high crystallinity, such as polypropylene (PP), polylactic acid (PLA), and polycaprolactone (PCL), to increase the crystallinity of PBAT. This improves the rigidity, heat resistance, and flowability of PBAT, enabling the preparation of PBAT-based meltblown nonwoven fabrics with polymer blend system modification via meltblown method. Furthermore, CN113106625A, CN114134598A, and CN114621566A increase the crystallinity of PBAT by adding additives such as nucleating agents, depolymerizing agents, accelerators, surfactants, and lubricants. This increases the thermal decomposition temperature and crystallization temperature of PBAT crystallization polymerization, enabling the preparation of additive-modified PBAT-based meltblown nonwoven fabrics via meltblown method.

[0006] However, in the above methods, the PBAT is modified by blending, and the proportion of polymer mixed with PBAT is high, accounting for at least 1 / 3 of the total material, so it is not pure PBAT meltblown nonwoven fabric. Furthermore, the PBAT material is modified by adding additives such as nucleating agents, depolymerizing agents, accelerators, surfactants and lubricants, among which nucleating agents, depolymerizing agents, accelerators, surfactants and lubricants contain inorganic and organic compounds, so it is not pure PBAT meltblown nonwoven fabric either.

[0007] Compared to polymer-blended and additive-modified PBAT meltblown nonwovens, pure PBAT meltblown nonwovens offer better toughness and can be used in a wider range of fields. Furthermore, with increasing environmental awareness, there is a greater demand for materials with high biodegradability. Modified PBAT, however, is mostly non-degradable or degrades slowly, exhibiting poorer degradation performance and slower degradation times compared to pure PBAT, which poses a threat to environmental protection.

[0008] Therefore, it is of great significance to study a PBAT meltblown nonwoven fabric and its meltblown air flow field preparation method to realize the preparation of pure PBAT nonwoven fabric. Summary of the Invention

[0009] To address the problems existing in the prior art, this invention provides a PBAT meltblown nonwoven fabric and a method for preparing the meltblown air flow field thereon;

[0010] To achieve the above objectives, the present invention adopts the following solution:

[0011] A method for preparing PBAT (polybutylene terephthalate) meltblown nonwoven fabric using a meltblown airflow field, wherein PBAT masterbatch is prepared by meltblown process to obtain PBAT meltblown nonwoven fabric;

[0012] In the meltblown process, the temperature of the drawing gas flow is 25-65℃, and the distance between the spinneret and the receiving web forming system (receiving distance) is 40-70cm.

[0013] PBAT masterbatch has a melting point above 120℃ and a thermal decomposition temperature above 200℃.

[0014] PBAT melt, a linearly linked polymer chain, is a pseudoplastic non-Newtonian fluid. Therefore, before being introduced into the die nozzle, its molecular chains are entangled in the liquid phase (melt). As the temperature of the polymer melt distribution system rises to 185°C, the intermolecular forces of PBAT decrease relatively, the molecular chain motion intensifies, the thermal motion of its atoms or ions increases dramatically, the distance between atoms or ions increases, the structure becomes looser, and the heat capacity and thermal expansion of the substance also increase. Furthermore, during the PBAT melt injection process, as the drawing gas pressure increases, the shear stress between the drawing gas pressure (turbulent airflow field) increases the flow velocity of the PBAT melt, and the shear viscosity or apparent viscosity of the PBAT melt decreases. At this point, the PBAT melt, generating heat and thermal effects, moves irregularly at a partial velocity perpendicular to the die nozzle axis, forming an unstable, non-isothermal melt fluid. Under the interaction of velocity and temperature in various regions of the stretching airflow pressure, frictional resistance is generated on the unstable molten fluid surface by two converging high-speed cold airflows (temperature below 65°C). This, combined with an increased receiving distance (at least 15cm more than conventional methods, and at least 40cm in this invention) and the action of the high-speed stretching airflow, stretches the PBAT melt to a finer diameter. During this process, a large number of PBAT polymer chains can be stretched and aligned. Further away from the die nozzle surface, the air jet (temperature below 65°C) entrains ambient air, cooling the molten fluid and causing it to solidify through crystallization, ultimately forming fibers. If the airflow temperature is too high (above 65°C), the thermal motion of the PBAT molecules becomes too intense, making it difficult for crystal nuclei to form. Furthermore, excessively high airflow temperatures reduce the viscosity of the melt, intensifying the diffusion of chain segments and inhibiting grain growth.

[0015] As a preferred technical solution:

[0016] The method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field as described above has a melt index of 17-23 g / 10 min for PBAT masterbatch at 190°C and 2.16 kg load.

[0017] The method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field as described above includes a meltblown process with a melting temperature of 180°C, a polymer melt distribution system temperature of 185°C, and a die temperature of 190°C.

[0018] In the method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field as described above, the pressure of the stretching airflow on both sides of the spinneret is 0.06 to 0.3 MPa.

[0019] The method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field as described above has a receiving web-forming system with a web-laying frequency of 1–5 Hz and a winding frequency of 2–6 Hz.

[0020] The method for preparing PBAT meltblown nonwoven fabric using a meltblown air jet flow field, as described above, uses a metering pump frequency of 5–30 Hz.

[0021] The present invention also provides a PBAT meltblown nonwoven fabric prepared by the method described in any of the preceding claims, wherein the PBAT meltblown nonwoven fabric has an elongation at break of 160-180% and excellent toughness.

[0022] According to the GB / T 41010-2021 standard, PBAT meltblown nonwoven fabric was tested for degradation in soil and marine environments. Under soil landfill conditions, it completely degraded after 5 months of burial. Immersing it in seawater resulted in complete degradation within 30-60 days. This improved process significantly enhances the degradation performance of PBAT meltblown nonwoven fabric. Existing technologies use polymers with high heat resistance and high crystallinity, as well as additives such as nucleating agents, depolymerizing agents, accelerators, surfactants, and lubricants. Most of these are non-degradable or slow-degrading materials. The resulting blended PBAT nonwoven fabric, modified with pure PBAT, exhibits worse degradation performance and a slower degradation time compared to pure PBAT nonwoven fabric. This poses a threat to the environment.

[0023] Invention principle:

[0024] The raw material used in this invention is pure PBAT, without polymer mixing or additives. It has poor heat resistance and is difficult to cure and form in the high-speed hot airflow of existing technologies. The technical solution of this invention selects a receiving distance of at least 40cm and a low-temperature, high-airflow configuration to achieve rapid, high-ratio stretching, spinning, curing, and forming. Specifically:

[0025] Because PBAT crystallizes very slowly, the polymer chains require an even longer time to crystallize. A temperature field-airflow temperature-low temperature cooling method is used to increase the cooling rate, thereby reducing the cooling time and promoting the crystallization of PBAT. When the temperature reaches above the melting point of PBAT (above 120°C), the PBAT material begins to gradually melt into a molten state. The intermolecular forces of PBAT decrease relatively, the molecular chain motion intensifies, and the thermal motion of its atoms or ions is greatly enhanced. The distance between atoms or ions increases, the structure becomes looser, and the heat capacity and thermal expansion of the substance also increase. Then, the PBAT melt is rapidly cooled from a flowing state to a solid state. At this point, the PBAT molecules begin to arrange themselves in an orderly manner and form a regular crystal structure in space. With rapid low-temperature cooling and a decrease in the required cooling time, the spacing or intervals between these arrangements become smaller and smaller, and the molecules continuously aggregate to form crystalline blocks. Furthermore, as the temperature field—the airflow temperature—decreases, the morphology and microstructure of PBAT meltblown nonwoven fabric transform from a membrane or porous membrane (without fibers or fiber-free structure) to a biomimetic dendritic branched fiber network structure nonwoven fabric (with gradual emergence of fiber structures), then to a fiber-bonded network structure nonwoven fabric, and finally to a fiber network structure nonwoven fabric. Therefore, a lower temperature field—lower airflow temperature—more easily promotes the crystallization of PBAT fibers, which is beneficial for fiber forming and the preparation of PBAT fiber network structures.

[0026] In this invention, the distance between the roller receiver and the nozzle (receiving distance) is 40-70cm, which is longer than the receiving distance of traditional meltblown (25cm), thus extending the cooling time and promoting the crystallization degree of PBAT.

[0027] Most meltblown raw materials, such as PP (polypropylene), PE (polyethylene), PS (polystyrene), PBT (polybutylene terephthalate), PC (polycarbonate), PTT (polypropylene terephthalate), TPU (thermoplastic polyurethane), PA6 (polyamide 6), PEA (polyamide ester), polychlorotrifluoroethylene, PPS (polyphenylene sulfide), POM (polyoxymethylene), PLA (polylactic acid), PHA (polyhydroxyalkanoates), PCL (polycaprolactone), PET (polyethylene terephthalate), and PMMA (polymethyl acrylate), have good crystallization properties and fast crystallization rates. Therefore, their melts are instantly crystallized into fibrous solids when extruded. The reason for choosing high temperatures is that the hot air temperature of the airflow field will cause the fibrous solids to semi-melt (quasi-solid). Then, the hot air in the airflow field with a large stretching pressure will stretch the quasi-solid fibers into finer fibers, resulting in meltblown fibers with smaller diameters.

[0028] Unlike the meltblown raw materials mentioned above, PBAT is a random copolymer with long molecular chains. The kinetic effects between molecular chain segments are difficult to coordinate, resulting in poor crystallization ability and a tendency to produce crystallization defects. The intermolecular forces are weak, and their potential energy is easily disrupted by turbulence and thermal motion. Therefore, PBAT has poor crystallization properties, and its melt cannot crystallize into a fibrous solid upon extrusion; it remains a melt. Therefore, a lower drawing gas temperature is used to allow the melt to form a fibrous solid. To obtain meltblown fibers with smaller diameters, the extruded melt needs to be drawn under the drawing pressure of the gas flow field.

[0029] Beneficial effects

[0030] (1) In the method for preparing PBAT meltblown nonwoven fabric by meltblown air jet flow field of the present invention, the crystallinity of PBAT is controlled by meltblown air jet flow field to achieve the preparation of pure PBAT nonwoven fabric. This is different from the "polymer blending system modification" and "additive crystallization modification" used in the prior art. The prior art increases the crystallinity of PBAT by mixing polymers or additives. The present invention improves the crystallinity of PBAT by controlling the meltblown air jet flow field parameters. The prior art does not produce pure PBAT nonwoven fabric, and the preparation process is long, requires modification, has many added components, poor compatibility, many preparation steps, and long process.

[0031] (2) In the method for preparing PBAT meltblown nonwoven fabric by meltblown air flow field of the present invention, the preparation parameters are subverted from the preparation parameters of the traditional meltblown process air flow field. The traditional meltblown process air flow field uses high-speed hot air flow, while the meltblown air flow field used in the present invention uses low-temperature high-speed cold air flow, which makes the process energy consumption low and the cost low.

[0032] (3) The PBAT meltblown nonwoven fabric prepared by the meltblown air flow field obtained by the present invention has better toughness. Due to its excellent toughness, it has the advantages of moderate tightness, good stretching, soft hand feel, good air permeability, and no tightness. Attached Figure Description

[0033] Figure 1 Analysis diagram of meltblown airflow field parameters for the preparation of PBAT meltblown nonwoven fabric;

[0034] Figure 2 This is a scanning electron microscope image of Example 1;

[0035] Figure 3 The image shown is a scanning electron microscope image of Comparative Example 1.

[0036] Figure 4 This is a scanning electron microscope image of Comparative Example 2. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0038] The PBAT masterbatch used in this invention is manufactured by Changchun Artificial Resin Factory Co., Ltd., and its brand name is ECO-A20.

[0039] Example 1

[0040] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field, the specific process of which is as follows: PBAT masterbatch is processed by meltblown process to obtain PBAT meltblown nonwoven fabric;

[0041] The meltblown process is as follows:

[0042] The metering pump frequency is 5Hz; the drawing gas pressure on both sides of the spinneret is 0.06MPa; in the meltblown process, the melting temperature is 180℃, the polymer melt distribution system temperature is 185℃, the die temperature is 190℃, the cooling rate is 50℃ / min; the drawing gas temperature is 25℃, and the distance between the spinneret and the receiving web forming system is 40cm.

[0043] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 160.42%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in soil landfill conditions in 118 days, and the PBAT meltblown nonwoven fabric can be completely degraded in seawater in 30 days.

[0044] like Figure 1 As shown, the airflow temperature has a significant impact on the morphology and microstructure of PBAT meltblown nonwoven fabric. As the airflow temperature decreases from 100℃ to 50℃, the morphology and microstructure of the PBAT meltblown nonwoven fabric transform from a membrane or porous membrane (without fibers or fiber-free structure) to a biomimetic dendritic branched fiber network structure (with gradual emergence of fiber structures), then to a fiber-bonded network structure, and finally to a fiber network structure. Therefore, a lower airflow temperature more readily promotes the crystallization of PBAT fibers, which is beneficial for fiber forming and the preparation of PBAT fiber network structures.

[0045] Comparative Example 1

[0046] A method for preparing PBAT meltblown nonwoven fabric is basically the same as in Example 1, except that the temperature of the stretching gas flow is 75°C.

[0047] The resulting PBAT meltblown nonwoven fabric had a breaking elongation of 114.19%.

[0048] Comparing Comparative Example 1 and Example 1, as follows: Figure 3 As shown, it can be found that when the airflow temperature is 75°C, the fibers in the surface morphology stick together, and the elongation at break is reduced by 46.23% compared with Example 1. This is because when the airflow temperature is too high, it cannot promote fiber crystallization and formation, the chain flexibility is reduced, the toughness is reduced, resulting in a decrease in the elongation at break compared with Example 1.

[0049] Comparative Example 2

[0050] A method for preparing a PBAT membrane is basically the same as in Example 1, except that the temperature of the stretching gas flow is 100°C.

[0051] The elongation at break of the prepared PBAT membrane was 11.36%.

[0052] Comparing Comparative Example 2 and Example 1, as follows: Figure 4 As shown, it can be found that when the airflow temperature is 100°C, the surface morphology is a film, and the elongation at break is reduced by 149.06% compared with Example 1. This is because when the airflow temperature is too high, it cannot promote fiber crystallization and formation, the chain flexibility decreases, the toughness decreases, resulting in a reduction in the elongation at break compared with Example 1.

[0053] Example 2

[0054] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field, the specific process of which is as follows: PBAT masterbatch is processed by meltblown process to obtain PBAT meltblown nonwoven fabric;

[0055] The meltblown process is as follows:

[0056] The metering pump frequency is 7Hz; the drawing air pressure on both sides of the spinneret is 0.1MPa; in the meltblown process, the melting temperature is 180℃, the polymer melt distribution system temperature is 185℃, the die temperature is 190℃; the drawing air temperature is 30℃, and the distance between the roller receiver and the nozzle is 45cm with a roller rotation speed of 2r / min.

[0057] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 162.53%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in 120 days under soil landfill conditions, and the PBAT meltblown nonwoven fabric can be completely degraded in 33 days when immersed in seawater.

[0058] Example 3

[0059] A method for preparing PBAT meltblown nonwoven fabric using a meltblown gas flow field is basically the same as in Example 2, except that the temperature of the stretching gas flow is 35°C.

[0060] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 163.41%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in 123 days under soil landfill conditions, and the PBAT meltblown nonwoven fabric can be completely degraded in 35 days when immersed in seawater.

[0061] Example 4

[0062] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field, the specific process of which is as follows: PBAT masterbatch is processed by meltblown process to obtain PBAT meltblown nonwoven fabric;

[0063] The meltblown process is as follows:

[0064] The metering pump frequency is 9Hz; the drawing air pressure on both sides of the spinneret is 0.15MPa; in the meltblown process, the melting temperature is 180℃, the polymer melt distribution system temperature is 185℃, the die temperature is 190℃; the drawing air temperature is 40℃, and the distance between the roller receiver and the nozzle is 50cm with a roller rotation speed of 3r / min.

[0065] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 165.74%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in 126 days under soil landfill conditions, and the PBAT meltblown nonwoven fabric can be completely degraded in 38 days when immersed in seawater.

[0066] Example 5

[0067] A method for preparing PBAT meltblown nonwoven fabric using a meltblown gas flow field is basically the same as in Example 4, except that the temperature of the stretching gas flow is 45°C.

[0068] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 167.16%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in 128 days under soil landfill conditions, and the PBAT meltblown nonwoven fabric can be completely degraded in 39 days when immersed in seawater.

[0069] Example 6

[0070] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field, the specific process of which is as follows: PBAT masterbatch is processed by meltblown process to obtain PBAT meltblown nonwoven fabric;

[0071] The meltblown process is as follows:

[0072] The metering pump frequency is 10Hz; the drawing air pressure on both sides of the spinneret is 0.2MPa; in the meltblown process, the melting temperature is 180℃, the polymer melt distribution system temperature is 185℃, the die temperature is 190℃; the drawing air temperature is 50℃, and the distance between the roller receiver and the nozzle is 55cm with a roller rotation speed of 4r / min.

[0073] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 170.27%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in soil landfill conditions in 133 days, and the PBAT meltblown nonwoven fabric can be completely degraded in seawater in 40 days.

[0074] Example 7

[0075] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field is basically the same as in Example 6, except that the temperature of the stretching airflow is 55°C.

[0076] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 172.73%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in soil landfill conditions in 137 days, and the PBAT meltblown nonwoven fabric can be completely degraded in seawater in 41 days.

[0077] Example 8

[0078] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field, the specific process of which is as follows: PBAT masterbatch is processed by meltblown process to obtain PBAT meltblown nonwoven fabric;

[0079] The meltblown process is as follows:

[0080] The metering pump frequency is 13Hz; the drawing air pressure on both sides of the spinneret is 0.25MPa; in the meltblown process, the melting temperature is 180℃, the polymer melt distribution system temperature is 185℃, the die temperature is 190℃; the drawing air temperature is 60℃, and the distance between the roller receiver and the nozzle is 60cm with a roller speed of 5r / min.

[0081] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 174.64%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in soil landfill conditions in 143 days, and the PBAT meltblown nonwoven fabric can be completely degraded in seawater in 43 days.

[0082] Example 9

[0083] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field is basically the same as in Example 8, except that the temperature of the stretching airflow is 65°C.

[0084] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 178.43%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in soil landfill conditions in 147 days, and the PBAT meltblown nonwoven fabric can be completely degraded in seawater in 44 days.

[0085] Example 10

[0086] A method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field, the specific process of which is as follows: PBAT masterbatch is processed by meltblown process to obtain PBAT meltblown nonwoven fabric;

[0087] The meltblown process is as follows:

[0088] The metering pump frequency is 15Hz; the drawing air pressure on both sides of the spinneret is 0.3MPa; in the meltblown process, the melting temperature is 180℃, the polymer melt distribution system temperature is 185℃, the die temperature is 190℃; the drawing air temperature is 65℃, and the distance between the roller receiver and the nozzle is 70cm with a roller speed of 5r / min.

[0089] The obtained PBAT meltblown nonwoven fabric has a breaking elongation of 180.64%. According to the GB / T 41010-2021 standard, the soil degradation and marine environment degradation of the PBAT meltblown nonwoven fabric can be completely degraded in soil landfill conditions in 150 days, and the PBAT meltblown nonwoven fabric can be completely degraded in seawater in 46 days.

Claims

1. A method for preparing PBAT meltblown nonwoven fabric using a meltblown air jet flow field, characterized in that: PBAT masterbatch is used to prepare PBAT meltblown nonwoven fabric through a meltblown process; The melt index of PBAT masterbatch at 190℃ and 2.16kg load is 17~23g / 10min; In the meltblown process, the temperature of the drawing gas flow is 25~65℃, the distance between the spinneret and the receiving web forming system is 40~70cm, and the pressure of the drawing gas flow on both sides of the spinneret hole is 0.06~0.3MPa. PBAT masterbatch has a melting point above 120℃ and a thermal decomposition temperature above 200℃.

2. The method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field according to claim 1, characterized in that, In the meltblown process, the melting temperature is 180℃, the polymer melt distribution system temperature is 185℃, and the die head temperature is 190℃.

3. The method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field according to claim 1, characterized in that, The receiving network system has a network laying frequency of 1~5Hz and a winding frequency of 2~6Hz.

4. The method for preparing PBAT meltblown nonwoven fabric using a meltblown airflow field according to claim 1, characterized in that, The metering pump frequency is 5~30Hz.

5. The PBAT meltblown nonwoven fabric prepared by the method according to any one of claims 1 to 4, characterized in that: The elongation at break of PBAT meltblown nonwoven fabric is 160-180%; According to the GB / T 41010-2021 standard, the degradation of PBAT meltblown nonwoven fabric in soil and marine environment was tested. It can be completely degraded in soil landfill conditions in 5 months. When PBAT meltblown nonwoven fabric is immersed in seawater, it can be completely degraded in 30 to 60 days.

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