A Degradable High-Electrostatic Adsorption Poly(lactic acid) Meltblown Material and Its Preparation Method

Abstract

The present invention provides a degradable high electrostatic adsorption polylactic acid meltblown material, its preparation method and application, belonging to the field of meltblown materials. The present invention provides a degradable high electrostatic adsorption polylactic acid meltblown material, comprising the following components in mass percentages: 96.5% - 97.6% of polylactic acid, 0.1% - 0.3% of crosslinking agent, 0.1% - 0.3% of antioxidant, 0.5% - 0.7% of lubricant, 0.5% - 1% of organic electret powder and 0.2% - 0.8% of nucleating agent; the sum of the mass percentages of each component is 100%. The present invention provides a degradable high electrostatic adsorption polylactic acid meltblown material, which has a high electrostatic adsorption effect and good corona electret ability, can greatly improve the electret effect of the obtained meltblown cloth and keep it from losing for a long time, and overcomes the shortcoming that the electrostatic adsorption ability of the conventional meltblown cloth weakens over time after corona electret treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of meltblown materials, and particularly to a degradable high electrostatic adsorption polylactic acid meltblown material and a preparation method thereof. Background Art

[0002] Meltblown cloth belongs to a kind of non-woven fabric, which has excellent barrier filtration and air permeability, and is widely used in the fields of medical protection, sanitary cleaning materials, filtration materials, etc. In recent years, the demand for meltblown cloth has been increasing continuously, and the demand for its resin raw materials has also increased accordingly. The main production raw materials of meltblown cloth are polypropylene, polyester, etc. Among them, polypropylene is the most widely used. However, with the rapid development of industrialization, more and more attention is paid to the environmental protection industry. Polypropylene raw materials rely on non-renewable petroleum resources, and the materials are non-degradable after being discarded, which is not conducive to the sustainable development of social resources; polylactic acid is a completely biodegradable aliphatic polyester material prepared by chemical synthesis from renewable resources, and has good mechanical strength, biocompatibility, absorbability and biodegradability. This characteristic has attracted great attention to polylactic acid in the fields of medical materials and environmental protection applications.

[0003] Traditional polylactic acid meltblown materials have the disadvantage that the electrostatic adsorption ability weakens over time after corona electret treatment. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a degradable high electrostatic adsorption polylactic acid meltblown material and a preparation method thereof. The degradable high electrostatic adsorption polylactic acid meltblown material provided by the present invention has long-term electrostatic adsorption performance and good corona electret ability.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a degradable high electrostatic adsorption polylactic acid meltblown material, comprising the following components in mass percentage:

[0007] Polylactic acid 96.5% - 97.6%, crosslinking agent 0.1% - 0.3%, antioxidant 0.1% - 0.3%, lubricant 0.5% - 0.7%, organic electret powder 0.5% - 1% and nucleating agent 0.2% - 0.8%;

[0008] The sum of the mass percentages of each component is 100%.

[0009] Preferably, the degradable high electrostatic adsorption polylactic acid meltblown material comprises the following components in mass percentage:

[0010] Polylactic acid 97.5%, crosslinking agent 0.2%, antioxidant 0.3%, lubricant 0.7%, organic electret powder 0.5% and nucleating agent 0.8%.

[0011] Preferably, the degradable high electrostatic adsorption polylactic acid meltblown material comprises the following components in percentage by mass:

[0012] 97.4% of polylactic acid, 0.2% of crosslinking agent, 0.3% of antioxidant, 0.7% of lubricant, 1% of organic electret powder and 0.4% of nucleating agent.

[0013] Preferably, the organic electret powder comprises polytetrafluoroethylene micropowder.

[0014] Preferably, the polylactic acid comprises L-polylactic acid.

[0015] Preferably, the crosslinking agent comprises bis(tert-butylperoxyisopropyl)benzene.

[0016] Preferably, the antioxidant comprises a primary antioxidant and a secondary antioxidant, and the mass ratio of the primary antioxidant to the secondary antioxidant is 2:1.

[0017] Preferably, the primary antioxidant comprises one or more of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hexanediamine, 4,4'-methylenebis(2,6-di-tert-butylphenol) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol).

[0018] Preferably, the secondary antioxidant comprises one or more of tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and dilauryl thiodipropionate.

[0019] The present invention also provides a preparation method of the degradable high electrostatic adsorption polylactic acid meltblown material described in the above technical solution, comprising the following steps:

[0020] Melting and blending the polylactic acid, crosslinking agent, antioxidant, lubricant, organic electret powder and nucleating agent in sequence and then performing extrusion granulation to obtain the degradable high electrostatic adsorption polylactic acid meltblown material.

[0021] The present invention provides a degradable high electrostatic adsorption polylactic acid meltblown material, comprising the following components in percentage by mass: 96.5% - 97.6% of polylactic acid, 0.1% - 0.3% of crosslinking agent, 0.1% - 0.3% of antioxidant, 0.5% - 0.7% of lubricant, 0.5% - 1% of organic electret powder and 0.2% - 0.8% of nucleating agent; the sum of the mass percentages of each component is 100%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a degradable high electrostatic adsorption polylactic acid meltblown material, which has a high electrostatic adsorption effect and good corona electret ability, can greatly improve the electret effect of the obtained meltblown cloth and maintain it without loss for a long time, and overcomes the defect that the electrostatic adsorption ability of the conventional meltblown cloth weakens over time after corona electret treatment.

[0024] The present invention also provides a preparation method of the degradable high electrostatic adsorption polylactic acid meltblown material described in the above technical solution. The preparation method of the present invention is simple in operation and suitable for industrial application. Specific Embodiments

[0025] The present invention provides a degradable high electrostatic adsorption polylactic acid meltblown material, comprising the following components in mass percentages:

[0026] Polylactic acid (PLA) 96.5% - 97.6%, crosslinking agent 0.1% - 0.3%, antioxidant 0.1% - 0.3%, lubricant 0.5% - 0.7%, organic electret powder 0.5% - 1% and nucleating agent 0.2% - 0.8%;

[0027] The sum of the mass percentages of each component is 100%.

[0028] In the present invention, the degradable high electrostatic adsorption polylactic acid meltblown material preferably comprises the following components in mass percentages:

[0029] Polylactic acid 97.5%, crosslinking agent 0.2%, antioxidant 0.3%, lubricant 0.7%, organic electret powder 0.5% and nucleating agent 0.8%; or comprises the following components in mass percentages:

[0030] Polylactic acid 97.4%, crosslinking agent 0.2%, antioxidant 0.3%, lubricant 0.7%, organic electret powder 1% and nucleating agent 0.4%.

[0031] In the present invention, unless otherwise specified, the raw materials used are all commercially available products in the art.

[0032] In the present invention, the organic electret powder preferably comprises polytetrafluoroethylene micropowder (PTFE micropowder).

[0033] In the present invention, the particle size of the polytetrafluoroethylene micropowder is preferably 5 - 10 μm.

[0034] In the present invention, the polylactic acid preferably comprises L-polylactic acid.

[0035] In the present invention, the crosslinking agent preferably comprises bis(tert-butylperoxy)diisopropylbenzene (BIPB).

[0036] In the present invention, the antioxidant preferably includes a primary antioxidant and a secondary antioxidant, and the mass ratio of the primary antioxidant to the secondary antioxidant is preferably 2:1.

[0037] In the present invention, the primary antioxidant preferably includes one or more of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1076), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hexanediamine (1010), 4,4'-methylenebis(2,6-di-tert-butylphenol), and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (2246).

[0038] In the present invention, the secondary antioxidant preferably includes one or more of tris(2,4-di-tert-butylphenyl) phosphite (168), pentaerythritol bis(2,4-di-tert-butylphenyl) diphosphite, pentaerythritol bis(2,4-di-tert-butylphenyl) diphosphite, and dilauryl thiodipropionate.

[0039] In the present invention, the lubricant preferably includes one or more of calcium stearate, zinc stearate, erucamide, and ethylene bisstearamide.

[0040] In the present invention, the nucleating agent preferably includes TMC-300.

[0041] The present invention also provides a method for preparing the degradable high electrostatic adsorption polylactic acid meltblown material described in the above technical solution, including the following steps:

[0042] Melting and blending and extrusion granulation are carried out in sequence on polylactic acid, a crosslinking agent, an antioxidant, a lubricant, an organic electret powder, and a nucleating agent to obtain the degradable high electrostatic adsorption polylactic acid meltblown material.

[0043] The present invention has no special limitation on the specific manner of the melting and blending and extrusion granulation, and the manner well-known to those skilled in the art can be adopted.

[0044] In the present invention, the melting and blending and extrusion granulation are preferably carried out in a twin-screw extruder.

[0045] In the present invention, the temperature settings of each section of the twin-screw extruder are preferably as shown in Table 1:

[0046] Table 1 Temperatures of Each Section of the Twin-Screw Extruder

[0047]

[0048] To further illustrate the present invention, the degradable high electrostatic adsorption polylactic acid meltblown material provided by the present invention and its preparation method will be described in detail below with reference to examples, but they should not be construed as limiting the protection scope of the present invention.

[0049] Example 1

[0050] In this example, the proportion relationship of raw materials is as follows: by mass percentage, 97.5% of polylactic acid, 0.2% of bis(tert-butylperoxyisopropyl)benzene (BIPB), 0.2% of antioxidant 1010, 0.1% of antioxidant 168, 0.2% of erucic acid amide, 0.5% of ethylene bisstearamide, 0.8% of TMC-300, and 0.5% of PTFE micropowder (particle size of 5 μm).

[0051] Place the polylactic acid in a vacuum drying oven and dry it at 80 °C for 12 h; premix the dried polylactic acid with other components according to the above ratio in a high-speed mixer, and then melt-blend and extrude granulate through a twin-screw extruder. The temperature settings of each section of the twin-screw extruder are shown in Table 1.

[0052] Example 2

[0053] In this example, the proportion relationship of raw materials is as follows: by mass percentage, 97.4% of polylactic acid, 0.2% of bis(tert-butylperoxyisopropyl)benzene (BIPB), 0.2% of antioxidant 1010, 0.1% of antioxidant 168, 0.2% of erucic acid amide, 0.5% of ethylene bisstearamide, 0.5% of TMC-300, and 0.4% of PTFE micropowder (particle size of 5 μm).

[0054] The preparation method is the same as that of Example 1.

[0055] Example 3

[0056] In this example, the proportion relationship of raw materials is as follows: by mass percentage, 97.4% of polylactic acid, 0.2% of bis(tert-butylperoxyisopropyl)benzene (BIPB), 0.2% of antioxidant 1010, 0.1% of antioxidant 168, 0.2% of erucic acid amide, 0.5% of ethylene bisstearamide, 0.5% of TMC-300, and 0.4% of PTFE micropowder (particle size of 10 μm).

[0057] The preparation method is the same as that of Example 1.

[0058] Comparative Example 1

[0059] In this comparative example, the mixing ratio of raw materials is as follows: by mass percentage, polylactic acid is 65.4%, poly(butylene adipate-co-terephthalate) (PBAT) is 32%, bis(tert-butylperoxyisopropyl)benzene (BIPB) is 0.2%, antioxidant 1010 is 0.2%, antioxidant 168 is 0.1%, erucamide is 0.2%, ethylene bisstearamide is 0.5%, TMC-300 is 0.4%, and PTFE micropowder (particle size is 5 μm) is 1%.

[0060] The preparation method is the same as that of Example 1.

[0061] Comparative Example 2

[0062] In this comparative example, the mixing ratio of raw materials is as follows: by mass percentage, poly(butylene adipate-co-terephthalate) (PBAT) is 97.4%, bis(tert-butylperoxyisopropyl)benzene (BIPB) is 0.2%, antioxidant 1010 is 0.2%, antioxidant 168 is 0.1%, erucamide is 0.2%, ethylene bisstearamide is 0.5%, TMC-300 is 0.4%, and PTFE micropowder (particle size is 5 μm) is 1%.

[0063] The preparation method is the same as that of Example 1.

[0064] Comparative Example 3

[0065] Commercially available melt-blown polypropylene material

[0066] Comparative Example 4

[0067] In this comparative example, the mixing ratio of raw materials is as follows: by mass percentage, polylactic acid is 98.4%, bis(tert-butylperoxyisopropyl)benzene (BIPB) is 0.2%, antioxidant 1010 is 0.2%, antioxidant 168 is 0.1%, erucamide is 0.2%, ethylene bisstearamide is 0.5%, and TMC-300 is 0.4%.

[0068] The products obtained from the examples and comparative examples were subjected to melt - blown spinning tests on a melt - blown cloth machine, and their performance was tested. The filtration efficiency and air resistance of the finally produced melt - blown cloth were measured. The test conditions were as follows: Melt - blown cloth spinning machine: Extrusion temperature 180°C. The test results are shown in Table 2. As can be seen from Table 2, the test results of Examples 1 - 3 are all better than those of Comparative Examples 1 - 2. Although the overall filtration efficiency of Comparative Example 1 is as high as 99.1%, the surface of the cloth is rough, fuzzing occurs, and the cloth is hard and brittle, with an air resistance of more than 200 Pa, so it cannot be regarded as a qualified product. After adding nucleating agents in Examples 1 - 3, the crystallinity of polylactic acid was increased, the molding cycle was accelerated, and the surface appearance was better than that of Comparative Example 1. However, the proportion of nucleating agent added in Example 1 is greater than that in Examples 2 and 3. The high - proportion nucleating agent accelerated the crystallization of polylactic acid, resulting in a relatively lower melt index compared to Examples 2 and 3. The melt index of the melt - blown material is crucial for the formation of melt - blown cloth. The higher the melt index, the softer the produced melt - blown cloth and the relatively lower the air resistance. Therefore, the air resistance of the melt - blown cloth in Example 1 is greater than that in Examples 2 and 3. Thus, the nucleating agent proportion in Examples 2 and 3 is more optimal; after adding organic electret powder in Examples 1 - 3, it can be seen that the change in the filtration grade of the melt - blown cloth after standing for 30 days at room temperature is significantly better than that of Comparative Examples 1 - 3, and Examples 2 and 3 are also better than Example 1 because a higher content of organic electret powder was added in Examples 2 and 3; compared with Comparative Example 3, the data of Examples 1 - 3 are comparable, but Comparative Example 3 is a commercially available polypropylene melt - blown material, which cannot be degraded and is difficult to achieve sustainable resource utilization; no organic electret powder was added in Comparative Example 4. From the data, it can be seen that after standing for 30 days, the filtration grade of Comparative Example 4 decreased significantly. At the same time, although Example 3 used PTFE fine powder with a larger particle size and the key filtration grade and the filtration grade after standing for one month were close to those of Example 2, the overall appearance of the melt - blown cloth was not ideal, with problems such as fuzzing, hard and brittle feel. The ability of antistatic adsorption is mainly reflected in the oil - based filtration grade of the melt - blown cloth and the change in the filtration grade after standing for one month. The stronger the static adsorption ability, the higher the filtration grade. The decrease in the filtration grade of Example 2 after standing for one month is very small, proving that the present invention has excellent static adsorption ability. If the filtration grade drops significantly after standing for one month, it means that after corona treatment, only the charge is temporarily retained and the charge migrates over time, resulting in a decrease in the filtration grade due to the loss of charge migration and release. Therefore, Example 2 is the best solution.

[0069] Table 2 Test results of melt - blown spinning samples of examples and comparative examples

[0070]

[0071]

[0072] The above are only the preferred embodiments of the present invention and do not impose any formal limitations on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A degradable high electrostatic adsorption polylactic acid meltblown material, characterized in that, Comprising the following components by mass percentage: 97.4% of polylactic acid, 0.2% of diisopropylbenzene bis(tert-butylperoxide), 0.2% of antioxidant 1010, 0.1% of antioxidant 168, 0.2% of erucamide, 0.5% of ethylene bisstearamide, 1% of organic electret powder and 0.4% of nucleating agent; the organic electret powder is polytetrafluoroethylene micropowder, the particle size of the polytetrafluoroethylene micropowder is 5 μm, and the nucleating agent is TMC-300.

2. The biodegradable high electrostatic adsorption polylactic acid meltblown material according to claim 1, wherein The polylactic acid includes L-polylactic acid.

3. The preparation method of the degradable high electrostatic adsorption polylactic acid meltblown material according to claim 1 or 2, characterized in that, Comprising the following steps: Melting and blending and extrusion granulation are sequentially carried out on polylactic acid, diisopropylbenzene bis(tert-butylperoxide), antioxidant 1010, antioxidant 168, erucamide, ethylene bisstearamide, organic electret powder and nucleating agent to obtain the degradable high electrostatic adsorption polylactic acid meltblown material.

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