Preparation method of degradable PP melt-blown film

Abstract

The invention discloses a preparation method and application of a degradable pp melt-blown film, and the preparation method comprises the following steps: (1) putting an oxidant and pp into a stirrer, and uniformly mixing to prepare blended master batch; (2) melting and spraying out the obtained blended master batch, and forming blended fibers after high-temperature airflow high-speed drafting; and (3) cooling the fibers in air to form a net, and collecting to obtain the degradable melt-blown film. According to the method, the oxidant and the PP are blended and melt-blown, and the oxidant can be utilized to initiate the oxidation of the polymer, so that the molecular weight of the polymer is reduced, a hydrophilic group is formed, the long chain of polyolefin is decomposed, the degradation of the PP component is effectively promoted, and an effective method is provided for the degradation of the PP.

Description

Technical Field

[0001] The invention relates to the technical field of textile materials, and in particular to a method for preparing a degradable PP melt-blown film. Background Art

[0002] Meltblown polypropylene (PP) nonwovens are widely used due to their low cost, high yield, simple manufacturing process and good filtration effect. However, its high molecular weight and hydrophobicity make it water-resistant, inhibit microbial invasion, increase its own lifespan and highly resistant to degradation. Therefore, the accumulation of PP on different lands has led to long-term waste deposition problems.

[0003] In order to solve the problems of PP deposition and non-degradability, various methods have been sought and studied to enhance the composition of new materials for PP degradation, so that it can give full play to its advantages and alleviate environmental pressure. The patent with application number CN202010802318.7 discloses a high-strength degradable PP composite material, which includes the following components in parts by weight: polypropylene 45-90, regenerated silk 25-55, initiator 1-3, toughening agent 5-15, compatibilizer 1-15, antioxidant 0.1-2.5, lubricant 0.2-0.5, nucleating agent 0.5-3. The above materials are melt-blended and then melt-blown to obtain a milder and more degradable PP material, but the additives used are of various types, and the processes are numerous and costly.

[0004] To this end, the present application found that a small amount of pro-oxidant can change the properties of the composite membrane surface from hydrophobic to hydrophilic, resulting in accelerated decomposition of polyolefin long chains, providing a promising technology for PP degradation. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a degradable PP air filter membrane in view of the non-degradability of existing PP air filter membranes, the large-scale accumulation of which leads to long-term environmental and waste management problems. The method utilizes a pro-oxidant to change the membrane properties from hydrophobic to hydrophilic, which can lead to the decomposition of polyolefin long chains, thereby solving the problem of slow degradation of large-scale deposition of PP.

[0006] Another object of the present invention is to provide a degradable melt-blown film prepared by the above preparation method.

[0007] The technical solution adopted to achieve the purpose of the present invention is:

[0008] A method for preparing a degradable melt-blown film comprises the following steps:

[0009] 1. A method for preparing a degradable PP melt-blown film, characterized in that it comprises the following steps:

[0010] (1) putting the pro-oxidant and PP into a blender and mixing them evenly to prepare a blended masterbatch;

[0011] (2) the obtained blended masterbatch is melted and sprayed, and then drawn by high-temperature airflow at high speed to form a blended fiber,

[0012] (3) The fibers are cooled in air to form a web, and then collected to obtain a degradable PP melt-blown film.

[0013] 2. In the above technical solution, in the step (1), the pro-oxidant includes one of cobalt stearate, iron stearate, and copper stearate;

[0014] 3. In the above technical solution, in the step (1), the mass ratio of cobalt stearate to polypropylene is (0-2):100.

[0015] 4. In the above technical solution, in step (2), the temperature of each section of the single screw extruder is: 215-220°C in screw zone 1, 270-275°C in screw zone 2, and 285-290°C in screw zone 3;

[0016] The pipeline temperature is 260-270℃; the metering pump temperature is 250-260℃; the die head temperature is 250-255℃, and the air flow temperature is 200-210℃.

[0017] 5. In the above technical solution, the extrusion speed of the single screw extruder is 8.5-9.5 mL min -1 , metering pump flow rate is 7-9mL·min -1 The die head spinneret hole is 0.3-0.5mm, and the high-temperature air flow pressure is 0.03-0.04MPa.

[0018] 6. In the above technical solution, in step (3), the speed of the net curtain is 35-45cm·min -1 ; Winding speed is 15-25cm·min -1 ; The distance from the die head to the mesh curtain is 15-20cm.

[0019] In another aspect of the present invention, the degradable PP melt-blown film is prepared by the above-mentioned preparation method.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The preparation method of the PP degradable melt-blown film provided by the present invention uses metal stearate to fill the polypropylene masterbatch, promotes the redox reaction, forms free radicals to promote the degradation of the material, thus effectively solving the problem of non-degradable PP deposition.

[0022] 2. The air filter membrane provided by the present invention is biodegradable and more environmentally friendly and green than traditional commercial filter membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is the TG analysis of the degradable melt-blown films prepared in Examples 1-4;

[0024] Figure 2 Shown is the DSC analysis of the degradable melt-blown films prepared in Examples 1-4;

[0025] Figure 3 Shown are XRD patterns of the degradable melt-blown films prepared in Examples 1-4; DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] Example 1

[0028] A method for preparing a degradable PP melt-blown film, comprising the following steps:

[0029] (1) Weighing cobalt stearate powder and polypropylene in a mass ratio of 2:100, putting them into a blender and mixing them evenly to prepare a blending masterbatch;

[0030] (2) melt-spraying the obtained blended masterbatch, and forming a blended fiber after high-speed drawing by high-temperature airflow;

[0031] The temperature of the screw zone 1, screw zone 2, screw zone 3 and screw zone 3 in the single screw extruder is 220°C, 275°C and 290°C respectively; the pipeline temperature is 270°C; the metering pump temperature is 260°C; the die head temperature is 252°C; and the air flow temperature is 200°C. The extrusion speed of the single screw extruder is 9.1mL·min-1, the metering pump is 8mL·min-1, the die head spinneret hole is 0.3mm, and the high temperature air flow is 200°C.

[0032] The flow pressure is 0.35MPa.

[0033] (3) The fibers are cooled in air to form a web, which is then collected to obtain a degradable melt-blown film.

[0034] The speed of the net curtain is 40cm·min -1 ; Winding speed is 20cm·min -1 ; The distance from the die head to the mesh curtain is 20cm.

[0035] Example 2

[0036] A method for preparing a degradable PP melt-blown film, comprising the following steps:

[0037] (1) Weighing cobalt stearate powder and polypropylene in a mass ratio of 4:100, putting them into a blender and mixing them evenly to prepare a blending masterbatch;

[0038] (2) melt-spraying the obtained blended masterbatch, and forming a blended fiber after high-speed drawing by high-temperature airflow;

[0039] Among them, the temperature of the screw zone 1 in the single screw extruder is 220℃, the temperature of the screw zone 2 is 275℃, the temperature of the screw zone 3 is 290℃; the pipeline temperature is 270℃; the temperature of the metering pump is 260℃; the temperature of the die head is 252℃; the air flow temperature is 200℃. The extrusion speed of the single screw extruder is 9.1mL·min-1, the metering pump is 8mL·min-1, the die head spinneret hole is 0.3mm, and the high-temperature air flow pressure is 0.35MPa.

[0040] (3) The fibers are cooled in air to form a web, which is then collected to obtain a degradable melt-blown film.

[0041] The speed of the net curtain is 40cm·min -1 ; Winding speed is 20cm·min -1 ; The distance from the die head to the mesh curtain is 20cm.

[0042] Example 3

[0043] A method for preparing a degradable PP melt-blown film, comprising the following steps:

[0044] (1) Weighing cobalt stearate powder and polypropylene in a mass ratio of 8:100, putting them into a blender and mixing them evenly to prepare a blending masterbatch;

[0045] (2) melt-spraying the obtained blended masterbatch, and forming a blended fiber after high-speed drawing by high-temperature airflow;

[0046] Among them, the temperature of the screw zone 1 in the single screw extruder is 220℃, the temperature of the screw zone 2 is 275℃, the temperature of the screw zone 3 is 290℃; the pipeline temperature is 270℃; the temperature of the metering pump is 260℃; the temperature of the die head is 252℃; the air flow temperature is 200℃. The extrusion speed of the single screw extruder is 9.1mL·min-1, the metering pump is 8mL·min-1, the die head spinneret hole is 0.3mm, and the high-temperature air flow pressure is 0.35MPa.

[0047] (3) The fibers are cooled in air to form a web, which is then collected to obtain a degradable melt-blown film.

[0048] The speed of the net curtain is 40cm·min -1 ; Winding speed is 20cm·min -1 ; The distance from the die head to the mesh curtain is 20cm.

[0049] Example 4

[0050] A method for preparing a degradable PP melt-blown film, comprising the following steps:

[0051] (1) Weighing cobalt stearate powder and polypropylene in a mass ratio of 12:100, putting them into a blender and mixing them evenly to prepare a blending masterbatch;

[0052] (2) melt-spraying the obtained blended masterbatch, and forming a blended fiber after high-speed drawing by high-temperature airflow;

[0053] Among them, the temperature of the screw zone 1 in the single screw extruder is 220℃, the temperature of the screw zone 2 is 275℃, and the temperature of the screw zone 3 is

[0054] 290℃; pipeline temperature is 270℃; metering pump temperature is 260℃; die head temperature is 252℃; air flow temperature is 200℃. The extrusion speed of the single screw extruder is 9.1mL·min-1, the metering pump is 8mL·min-1, the die head spinneret hole is 0.3mm, and the high temperature air flow pressure is 0.35MPa.

[0055] (3) The fibers are cooled in air to form a web, which is then collected to obtain a degradable melt-blown film.

[0056] The speed of the net curtain is 40cm·min -1 ; Winding speed is 20cm·min -1 ; The distance from the die head to the mesh curtain is 20cm.

[0057] Figure 3 Shown is the thermal degradability of the prepared degradable melt-blown film, which proves that the presence of cobalt stearate reduces the crystallinity, thereby making the modified PP more easily degradable.

[0058] Figure 1 The thermogravimetric analysis diagram of the degradable melt-blown film prepared in Example 1-4 shows that with the increase of the concentration of peroxide CoSt, the thermal stability of the sample gradually decreases, which indicates that the addition of peroxide CoSt promotes the breakage and decomposition of the PP long chain, reduces the thermal stability of the PP melt-blown film, and has better thermal degradation performance.

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, all of which should be included in the protection scope of the present invention.

Claims

1. A method for preparing a degradable PP melt-blown film, characterized in that: The steps include: (1) putting the pro-oxidant and PP into a blender and mixing them evenly to prepare a blended masterbatch; (2) melt-blowing the obtained blended masterbatch using a melt-blowing machine, and forming a blended fiber after high-speed drawing by high-temperature airflow; (3) The fibers are cooled in air to form a web, which is then collected to obtain a degradable melt-blown film.

2. The method for preparing a degradable PP melt-blown film according to claim 1, characterized in that: In the step (1), the pro-oxidant includes one of cobalt stearate, iron stearate and copper stearate.

3. The method for preparing a degradable PP melt-blown film according to claim 1, characterized in that: In the step (1), the mass ratio of cobalt stearate to polypropylene is (0-12):

100.

4. The method for preparing a degradable PP melt-blown film according to claim 1, characterized in that: In the step (2), the temperature of each section of the single screw extruder is: 215-220°C in screw zone 1, 270-275°C in screw zone 2, and 285-290°C in screw zone 3; The pipeline temperature is 260-270℃; the metering pump temperature is 250-260℃; the die head temperature is 250-255℃, and the air flow temperature is 200-210℃.

5. The method for preparing a degradable PP melt-blown film according to claim 1, characterized in that: The extrusion speed of the single screw extruder is 8.5-9.5 mL min -1 , metering pump flow rate is 7-9mL·min -1 The die head spinneret hole is 0.3-0.5mm, and the high-temperature air flow pressure is 0.03-0.04MPa.

6. In the above technical solution, in step (2), the screen speed is 35-45 cm·min -1 ; The winding speed is 15-25cm·min-1; The distance from the die head to the mesh curtain is 15-20cm.

7. A degradable melt-blown film is prepared by the preparation method according to any one of claims 1 to 6.

8. The degradable PP melt-blown film according to claim 7, characterized in that: Compared with pure PP film, the crystallinity of CoSt / PP film is reduced by 25.13% and has a higher thermal degradation rate.

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