Electrostatic-assisted high-pressure flash spraying three-dimensional non-woven material and preparation method thereof

Abstract

The invention discloses an electrostatic-assisted high-pressure flash spraying three-dimensional non-woven material and a preparation method thereof, and belongs to the technical field of non-woven materials. According to the preparation method disclosed by the invention, the material is prepared by an electrostatic-assisted high-pressure flash spraying process, and in the preparation process, the action of electrostatic field force is introduced, so that the arrangement and distribution of micro-nano fibers in the prepared product can be effectively regulated and controlled, and the phenomena of non-uniform fiber dispersion or filament fiber agglomeration and the like are avoided; the film has good mechanical property, moisture permeability and barrier property, and meanwhile, the method is high in preparation efficiency and can realize continuous large-scale production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-woven materials, in particular to a static-electricity-assisted high-pressure flash-spun three-dimensional non-woven material and a preparation method thereof. BACKGROUND

[0002] In the prior art, non-woven materials are widely used, especially in the medical protection field (such as medical masks) which have basically replaced traditional materials as the main material. Among non-woven materials, high-pressure flash-spun non-woven materials have better mechanical properties and sealing properties, so their application prospect is better than that of other types of non-woven materials.

[0003] The preparation process of high-pressure flash-spun non-woven materials is generally as follows: the polymer is dissolved under high temperature and high pressure, then the polymer and the solvent in the spinning solution are phase-separated by means of instantaneous temperature loss and pressure loss, and then the solvent is volatilized and the polymer forms micro-nano-sized single-filament filaments, and finally the product is prepared through processes such as splitting and webbing and high-temperature hot rolling. However, unlike melt-blown non-woven materials, since the single-filament fineness of high-pressure flash-spun non-woven materials during preparation is mostly in the micro-nano scale, it is difficult to achieve controllable splitting and orderly arrangement of the filament bundles by relying solely on the force of the high-pressure gas flow, which may result in uneven splitting, poor mechanical properties and poor barrier properties of the prepared product. SUMMARY

[0004] Based on the defects of the prior art, the purpose of the present application is to provide a preparation method of three-dimensional non-woven materials, which uses a static-electricity-assisted high-pressure flash-spun process to prepare the materials. In the preparation process, the action of the electrostatic field force is introduced, which can effectively control the arrangement and distribution of the micro-nano fibers in the prepared product, and the product has excellent performance.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of three-dimensional non-woven materials, comprising the following steps:

[0007] (1) configuring a high-pressure flash-spun spinning solution;

[0008] (2) connecting a positive voltage of 5-40 kV to the spinneret of the high-pressure flash-spun device, setting the spinning pressure to 5-30 kPa and starting spinning; the spinning receiving device is a metal built-up belt with a hollow hole structure, and the built-up belt is connected to a ground wire or a negative voltage of -5 to -40 kV;

[0009] (3) hot rolling the collected spinning to obtain a three-dimensional non-woven material.

[0010] In the process of preparing non-woven materials by high-pressure flash jet technology, the uniformity and dispersity of fibers in the obtained material are only controlled by high-pressure airflow field force, but due to poor stability of the force field, the quality of the non-woven material prepared by the existing high-pressure flash jet technology is difficult to reach the expectation; and electrospinning technology is a technology for preparing high-uniformity three-dimensional fiber material by electrostatic field force, but due to limited electrostatic field force and the use of drum-type or flat-type receiving device to collect the product, the technology cannot realize continuous and effective mass production and uniformity production. In the method, the inventor combines the high-pressure flash jet technology and the electrospinning technology, sets positive voltage and negative voltage (or ground wire) on the high-pressure flash jet device and the receiving device, so that the jet head jetting the spinning fiber is subjected to the action of the high-pressure gas field force and the electrostatic field force at the same time, the distribution and uniformity of the jetted spinning fiber are double-regulated, and the situation that the fibers are of different lengths or long fibers are aggregated does not occur; meanwhile, the traditional receiving device is replaced by a metal accumulation belt with a hollow hole structure, under the action of the electrostatic field force after being connected to the ground wire or negative voltage, the spinning fiber further presents a specific three-dimensional structure when being collected to the metal accumulation belt, the obtained fiber has moderate size and high strength and uniformity; the final product obtained by hot rolling can exhibit good mechanical properties, moisture permeability and barrier properties.

[0011] Preferably, the positive voltage of step (2) is one of 5 kV, 6 kV, 8 kV, 10 kV, 12 kV, 15 kV, 20 kV, 25 kV, 30 kV, 35 kV, 40 kV or a range value of any two thereof.

[0012] Preferably, the set spinning pressure in step (2) is one of 5 kPa, 8 kPa, 10 kPa, 12 kPa, 15 kPa, 18 kPa, 20 kPa, 22 kPa, 25 kPa, 28 kPa, 30 kPa or a range value of any two thereof.

[0013] It should be noted that the set spinning pressure in the present application refers to the pressure of the high-pressure flash jet spinning solution when entering the jet head.

[0014] When high-pressure flash jet spinning is performed, the set voltage and spinning pressure have a great influence on the continuity and strength of the prepared spinning, and when the set conditions in the above preferred range are selected, the comprehensive performance of the prepared product is more optimal.

[0015] Preferably, the high-pressure flash jet spinning solution in step (1) comprises the following components in parts by weight: 2-15 parts of a polymer and 85-98 parts of a solvent; the polymer is at least one of polyethylene and polypropylene, and the solvent is at least one of dichloromethane and trichloromethane.

[0016] Preferably, the temperature of the high-pressure flash spinning solution in step (1) is 150-300℃.

[0017] In the high-pressure flash spinning, the material in the solution is fully dissolved and dispersed at a suitable temperature, so that the prepared web filament has better continuity, and the overall performance of the prepared three-dimensional non-woven material is better.

[0018] More preferably, the configuration method of the high-pressure flash spinning solution in step (1) is to mix the polymer and the solvent, then heat and mix under a pressure of 5-30kPa for 1-3h, to obtain the high-pressure flash spinning solution.

[0019] Preferably, the receiving distance of the spinning receiving device in step (2) is 10-120cm.

[0020] Preferably, the receiving distance of the spinning receiving device in step (2) is 15-100cm.

[0021] More preferably, the receiving distance of the spinning receiving device in step (2) is one of 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 50cm, 60cm, 70cm, 80cm, 90cm, 100cm or a range value of any two thereof.

[0022] It should be noted that the receiving distance of the spinning receiving device refers to the straight-line distance from the spinneret of the high-pressure flash spinning device to the spinning receiving device.

[0023] Preferably, the hole density of the hollow hole structure of the metal accumulation belt in step (2) is 20-150mesh.

[0024] Preferably, the hole density of the hollow hole structure of the metal accumulation belt in step (2) is 50-100mesh.

[0025] More preferably, the hole density of the hollow hole structure of the metal accumulation belt in step (2) is one of 50mesh, 60mesh, 65mesh, 70mesh, 80mesh, 90mesh, 100mesh or a range value of any two thereof.

[0026] In the spinning receiving, the hole density on the metal accumulation belt has a certain influence on the flow amount through the hollow structure, and also has a certain influence on the spinning laying effect and uniformity, and the product laid under the hole density in the above preferred range has better quality after hot rolling.

[0027] Preferably, the metal accumulation belt in step (2) is at least one of a stainless steel accumulation belt, a copper accumulation belt and an aluminum accumulation belt.

[0028] Preferably, the conveying speed of the metal accumulation belt in step (2) is 0.5-5 m / min.

[0029] Preferably, the temperature of the hot rolling in step (3) is 50-100℃.

[0030] Another object of the present application is to provide a three-dimensional nonwoven material prepared by the method for preparing the three-dimensional nonwoven material.

[0031] Still another object of the present application is to provide an application of the three-dimensional nonwoven material in preparing medical protective equipment.

[0032] Preferably, the medical protective equipment includes medical masks and medical membranes.

[0033] The present application has the advantages that the present application provides a three-dimensional nonwoven material and a method for preparing the same, the method uses electrostatic auxiliary high-pressure flash jet process to prepare the material, and the arrangement and distribution of micro-nano fibers in the prepared product can be effectively controlled based on the combined action of electrostatic field force and high-pressure airflow force, and the fibers will not be dispersed unevenly or aggregated into long fiber clusters, and the three-dimensional nonwoven material has good mechanical properties, moisture permeability and barrier properties, and the method has high preparation efficiency and can realize continuous mass production. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A flow chart of the method for preparing the three-dimensional nonwoven material of the present application, wherein 1 is a high-pressure reaction kettle, 2 is a high-pressure flash jet solution flow guide pipe, 3 is a high-pressure flash jet device spinneret, 4 is a positive voltage connection, 5 is a generated spinning solution, 6 is a negative voltage connection, 7 is a metal accumulation belt, 8 is a hot rolling lower roller, and 9 is a hot rolling upper roller.

[0035] Figure 2 A copper metal accumulation belt used in the method of Example 21 of the present application. DETAILED DESCRIPTION

[0036] In order to better illustrate the objects, technical solutions and advantages of the present application, the present application will be further described below in combination with specific examples and comparative examples, and the purpose is to understand the content of the present application in detail, rather than to limit the present application. All other examples obtained by those of ordinary skill in the art without creative labor fall within the protection scope of the present application. The experimental reagents and instruments involved in the implementation of the present application are common ordinary reagents and instruments unless otherwise specified.

[0037] Examples 1-16

[0038] Examples of the method for preparing the three-dimensional nonwoven material of the present application, the schematic flow chart of the preparation method is as follows Figure 1As shown, comprising the following steps:

[0039] (1) configure high pressure flash spinning solution;

[0040] (2) after connecting the positive voltage of AkV on the spinneret of the high pressure flash spinning device, set the spinning pressure to B kPa and start spinning; the spinning receiving device is a metal accumulation belt with a hollow hole structure, the accumulation belt is connected to the ground or negative voltage of C kV; the receiving distance of the spinning receiving device is D cm, the metal accumulation belt is a stainless steel accumulation belt, the hole density is E mesh, and the transmission speed is 10 m / min.

[0041] (3) heat the collected spinning at 70 DEG C to obtain a three-dimensional non-woven material.

[0042] The preparation method of the high pressure flash spinning solution in step (1) comprises the following steps:

[0043] Add 2500g of solvent dichloromethane and 200g of polyethylene powder into a high pressure reactor, heat to 200 DEG C, mix under 8MPa pressure for 2h to obtain a high pressure flash spinning solution.

[0044] The polyethylene powder is GUR4116 product produced by Celanese.

[0045] Example 17

[0046] The preparation method of the three-dimensional non-woven material of the application is different from that of example 1, except that the parameters are different,

[0047] The preparation method of the high pressure flash spinning solution in step (1) comprises the following steps:

[0048] Add 1500g of solvent dichloromethane, 1500g of solvent trichloromethane and 300g of polyethylene powder into a high pressure reactor, heat to 200 DEG C, mix under 8MPa pressure for 3h to obtain a high pressure flash spinning solution.

[0049] The metal accumulation belt is a copper accumulation belt, as Figure 2 shown.

[0050] The rest is the same as example 1.

[0051] The parameters are shown in table 1.

[0052] Table 1

[0053] Parameter A Voltage B Spinning pressure C Grounding voltage D Receiving distance E Gauge Example 1 15 15 -10 50 50 Example 2 5 15 -10 50 50 Example 3 30 15 -10 50 50 Example 4 40 15 -10 50 50 Example 5 15 5 -10 50 50 Example 6 15 20 -10 50 50 Example 7 15 30 -10 50 50 Example 8 15 15 -10 10 50 Example 9 15 15 -10 15 50 Example 10 15 15 -10 70 50 Example 11 15 15 -10 100 50 Example 12 15 15 -10 120 50 Example 13 15 15 -10 50 20 Example 14 15 15 -10 50 80 Example 15 15 15 -10 50 100 Example 16 15 15 -10 50 150 Example 17 15 15 -10 50 50 Comparative Example 1 / 15 / 50 50 Comparative Example 2 50 15 -10 50 50 Comparative Example 3 15 50 -10 50 50 Comparative Example 4 15 15 -10 50 /

[0054] Comparative examples 1-4

[0055] A method for preparing a three-dimensional nonwoven material, which differs from Example 1 only in that the process parameters in each of Table 1 are different.

[0056] In the comparative example 1, no positive voltage is connected to the spinneret of the high-pressure flash jet device; in the comparative example 4, the metal accumulation belt is a solid structure without a hollow hole structure.

[0057] Unless otherwise specified, the component raw materials used in each embodiment and comparative example of the present application are commercially available raw materials, and the component raw materials used in each parallel experiment are the same.

[0058] Example 1

[0059] In order to verify the performance of the three-dimensional nonwoven material prepared by the method of the present application, the products of each example and comparative example are tested for the following performance:

[0060] (1) Tensile strength before hot rolling: the three-dimensional nonwoven material before hot rolling is tested according to GB / T 3923.1-1997 standard, with a sample size of 50*150mm, a tensile speed of 100mm / min, and a method of testing;

[0061] (2) Tensile strength after hot rolling: the three-dimensional nonwoven material after hot rolling is tested for tensile strength using the same method as (1);

[0062] (3) Moisture permeability: the three-dimensional nonwoven material after hot rolling is tested according to GB / T19082-2009 standard, at 38℃ and 90% RH;

[0063] (4) Water pressure resistance: the three-dimensional nonwoven material after hot rolling is tested according to EN ISO 811:2018 standard, with a pressure increasing rate of 60cm H2O / min.

[0064] The test results are shown in Table 2.

[0065] Table 2

[0066]

[0067]

[0068] As can be seen from Table 1, the three-dimensional nonwoven material prepared by the preparation method of the present application has ideal comprehensive performance. The tensile strength of the product before hot rolling can reach more than 9.5N / 50m, and the tensile strength after hot rolling can reach more than 250N / 50m, with excellent mechanical properties; in terms of moisture permeability and water pressure resistance, the moisture permeability of the product can reach more than 3500g / m 2 24h, and the water pressure resistance can reach more than 20kPa, with equally ideal performance.

[0069] In the product preparation process, since the process of the application belongs to the combination of high-pressure flash jet technology and electrostatic spinning technology, the settings of voltage and spinning pressure are the most critical. As can be seen from Examples 1-4 and Comparative Examples 1-2, when no voltage is set, the product of Comparative Example 1 is at least a simple high-pressure flash jet preparation process, which only relies on the airflow field force to control the uniformity and dispersion of the spun fibers. Obviously, it cannot achieve the expected result, and the tensile strength, moisture permeability and water pressure resistance of the prepared product are all poor. With the setting of voltage, the electrostatic field force acts in the process, and the various indicators of the product are significantly improved. Especially when the voltage is set in the range of 15-30 kV, the tensile strength, moisture permeability and water pressure resistance of the product after hot rolling are better. However, if the voltage is set too high, as shown in Comparative Example 2, the electrostatic field force will instead have a counteracting force on the uniformity and dispersion of the spun fibers, and the performance of the product will also be significantly reduced. As shown in Examples 1, 5-7 and Comparative Example 3, compared with the electrostatic field force, the size of the spinning pressure force will also affect the quality of the spun fibers and thus the performance of the final product. Both forces need to be maintained at an appropriate level, otherwise, as shown in Comparative Example 3, too strong a spinning pressure will result in a product whose performance after hot rolling is even similar to that of the product of Comparative Example 1 without electrostatic field force.

[0070] On the other hand, after setting the voltage and pressure, the receiving distance of the spinning receiving device set during spinning will also affect the receiving laying effect. As can be seen from Examples 1 and 8-12, with the change of the receiving distance, the performance indicators of the product also change. When the receiving distance is set to 15-100 cm, the performance of the product is better.

[0071] As a spinning receiving device, the application based on the electrostatic-high-pressure flash jet combined spinning process technology needs to use a metal accumulation belt with a hollow structure. Under this structure, the airflow can fully flow during spinning reception, ensuring the uniformity and high dispersion of the fibers in the product and avoiding adhesion, so that the performance after hot rolling is excellent. Otherwise, as shown in the product of Comparative Example 4, using a conventional solid metal accumulation belt as a receiving device will result in poor receiving laying effect, and the performance of the final product prepared is naturally poor. As can be seen from Examples 1 and 13-16, the hole density of the hollow structure also affects the performance of the product. When the hole density is preferably 50-100 meshes, the performance of the final product prepared is better.

[0072] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the application and not to limit the protection scope of the application. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the application.

Claims

1. A method for preparing a three-dimensional nonwoven material, characterized in that: The following steps are involved: (1) preparing a high-pressure flash spinning solution; (2) After connecting a positive voltage of 5 to 40 kV to the spinneret of the high-voltage flash spray device, setting the spinning pressure to 5 to 30 kPa and starting spinning; the spinning receiving device is a metal integrated belt with a hollow hole structure, and the integrated belt is connected to the ground wire or a negative voltage of -5 to -40 kV; (3) The collected spun yarn is hot-rolled to obtain a three-dimensional nonwoven material.

2. The method for preparing a three-dimensional nonwoven material according to claim 1, wherein: The high-pressure flash spinning solution in step (1) comprises the following components in parts by weight: 2 to 15 parts of a polymer and 85 to 98 parts of a solvent; the polymer is at least one of polyethylene and polypropylene, and the solvent is at least one of dichloromethane and chloroform.

3. The method for preparing the three-dimensional nonwoven material according to claim 1, wherein: In the step (1), the temperature of the high-pressure flash spinning solution is 150-300°C.

4. The method for preparing a three-dimensional nonwoven material according to claim 1, wherein: The receiving distance of the spinning receiving device in the step (2) is 10 to 120 cm.

5. The method for preparing the three-dimensional nonwoven material according to claim 1, wherein: The pore density of the hollow hole structure of the metal tape in the step (2) is 20 to 150 meshes.

6. The method for preparing the three-dimensional nonwoven material according to claim 1, wherein: In the step (2), the metal accumulation belt is at least one of a stainless steel accumulation belt, a copper accumulation belt, and an aluminum accumulation belt.

7. The method for preparing the three-dimensional nonwoven material according to claim 1, wherein: The transmission speed of the metal belt in step (2) is 0.5-5 m / min.

8. The method for preparing the three-dimensional nonwoven material according to claim 1, wherein: The hot rolling temperature in step (3) is 50-100°C.

9. A three-dimensional nonwoven material prepared by the method for preparing a three-dimensional nonwoven material according to any one of claims 1 to 8.

10. Use of the three-dimensional nonwoven material according to claim 9 in the preparation of medical protective equipment.

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