Meltblown cloth, its manufacturing process and deodorizing mask prepared using the meltblown cloth

Abstract

This application relates to the field of mask manufacturing, specifically disclosing a meltblown fabric, its manufacturing process, and an odor-resistant mask made using the meltblown fabric. The meltblown fabric is made from the following raw materials in parts by weight: 12-15 parts polyvinyl acetate, 31-41 parts polypropylene, 19-23 parts polybutene, and 1.5-5 parts electret masterbatch. The meltblown fabric prepared in this application and the mask made using the meltblown fabric have low air resistance and excellent filtration efficiency. The preparation method of the meltblown fabric and mask provided in this application is convenient and efficient.

Description

Technical Field

[0001] This application relates to the field of mask manufacturing, and in particular to a meltblown fabric, its manufacturing process, and an odor-resistant mask made using the meltblown fabric. Background Technology

[0002] SMS-type masks consist of two S layers and one M layer. The S layer refers to the outer spunbond layer, and the M layer refers to the meltblown layer in the middle. The meltblown layer is usually formed by polypropylene meltblowing and has a good filtration effect.

[0003] Existing meltblown fabrics are mainly made of polypropylene. They have many pores, a loose structure, and good wrinkle resistance. The ultrafine fibers with unique capillary structures increase the number of fibers and surface area per unit area, thus giving meltblown fabrics excellent filtration and shielding properties. However, the air resistance of meltblown fabrics made of polypropylene is usually above 60Pa. In order to improve the protective effect, many masks sacrifice wearing comfort to increase the sealing of the mask. Filtering dust mechanically only increases the number of blocking filter elements. After layers are added, the breathing resistance becomes very high. Increasing the number of mask layers or the thickness and sealing of the mask can enhance the isolation effect. Although the filtration efficiency is improved, the wearer's experience is poor.

[0004] Therefore, it is necessary to develop a mask that provides good protection and is comfortable to wear. Summary of the Invention

[0005] In order to improve the discomfort caused by the wearing of existing masks in order to enhance the protective effect, the first objective of this application is to provide a meltblown fabric that has high bacterial filtration efficiency, high particulate matter filtration efficiency, good stability over time and high temperature stability.

[0006] The second objective of this application is to provide a method for preparing meltblown nonwoven fabric, which is convenient and can improve the production efficiency of meltblown nonwoven fabric.

[0007] The third objective of this application is to provide a method for preparing a mask, which is convenient and efficient in preparation; the mask prepared has good protective effect and low air resistance when worn, thus providing high wearing comfort.

[0008] The fourth objective of this application is to apply the prepared masks to children.

[0009] Firstly, the meltblown nonwoven fabric provided in this application adopts the following technical solution:

[0010] A meltblown nonwoven fabric, made from raw materials comprising the following parts by weight:

[0011] 12-15 parts of polyvinyl acetate

[0012] 31-41 parts of polypropylene

[0013] 19-23 parts of polybutene

[0014] 1.5-5 parts electret masterbatch.

[0015] By adopting the above technical solution, the addition of polyvinyl acetate and polybutene can correspondingly increase the toughness and plasticity of polypropylene fibers, improve the fluidity of the melt-blown fibers, and produce high fineness, small and uniform pores, high overlap, and improved support performance of the meltblown fiber web per unit area. Thus, even when the meltblown cloth is thin, it can achieve a good filtration effect. The addition of electret masterbatch can improve the fiber adsorption and increase its adsorption capacity for particulate matter and bacteria. Due to the improved adsorption capacity, the prepared meltblown fiber web still has excellent adsorption effect under low density and low air resistance.

[0016] Optionally, the raw materials for preparing the meltblown fabric may also include a fiber agent, which is selected from one or two of polylactic acid and cuprammonium fiber.

[0017] Optionally, the fiber agent is composed of polylactic acid and cuprammonium fiber in a weight ratio of (6-13):(7-14).

[0018] By adopting the above technical solutions, polylactic acid (PLA) is low-carbon, environmentally friendly, biodegradable, and naturally antibacterial, while cupro fiber has stable performance. After adding PLA and cupro fiber, the bacterial filtration efficiency and particulate filtration efficiency of the prepared meltblown fabric are improved. In addition, compared with adding PLA or cupro fiber alone, the combination of the two can produce a synergistic effect on the change rate of particulate filtration efficiency over time, the change rate of bacterial filtration efficiency over time, and the change rate of high-temperature bacterial filtration efficiency, thereby enhancing the long-term stability and high-temperature resistance of the mask. This results in higher filtration performance and stability of the prepared meltblown fabric, making it suitable for high-temperature environments.

[0019] Optionally, the raw materials for preparing the meltblown fabric may also include additives, which are composed of lubricants, stabilizers, and monosaccharides;

[0020] The lubricant is one or more of glyceryl trihydroxystearate, oxidized polyethylene wax, Fischer-Tropsch wax, and stearic acid;

[0021] The stabilizer is one or more of cadmium ricinoleate, calcium stearate, calcium ricinoleate, and magnesium stearate.

[0022] The monosaccharide is one or both of glucose and sorbitol.

[0023] Preferably, the lubricant is glyceryl trihydroxystearate, the stabilizer is calcium ricinoleate, and the monosaccharide is sorbitol.

[0024] Preferably, the additive is composed of glyceryl trihydroxy stearate, calcium ricinoleate and sorbitol in a weight ratio of (0.5-4):(1-4):(0.5-2).

[0025] By adopting the above technical solution and adding glycerol trihydroxy stearate, calcium ricinoleate, and sorbitol, the bacterial filtration efficiency and particulate matter filtration efficiency of meltblown fabric can be improved. At the same time, the rate of change in filtration efficiency of meltblown fabric within a certain effective period can be reduced, and the total number of bacterial colonies in the prepared masks can be reduced. This may be because the addition of glycerol trihydroxy stearate, calcium ricinoleate, and sorbitol enhances the dispersion performance of the prepared meltblown fibers, making them less prone to adhesion, and they also have suitable viscosity and high fiber output stability.

[0026] Optionally, the raw materials for preparing the meltblown fabric may also include 0.5-1.2 parts by weight of clove flower extract.

[0027] By adopting the above technical solution, the total number of bacterial colonies in the meltblown fabric prepared by adding clove extract is reduced, and the color is light and the smell is fresh. This may be because clove extract can inhibit mold and effectively inhibit the growth and reproduction of mold.

[0028] Optionally, the polypropylene is α-crystalline isotactic polypropylene or β-crystalline isotactic polypropylene.

[0029] Preferably, the polypropylene is α-crystalline isotactic polypropylene; more preferably, the polypropylene is 90% α-crystalline isotactic polypropylene, and the α-crystalline isotactic polypropylene has a melt flow index (MFI) of 400–1200 g / 10 min and a melt flow index ≥1500.

[0030] By adopting the above technical solution, the ventilation resistance of the mask prepared from 90% α-crystalline isotactic polypropylene is further reduced. The α-crystalline polypropylene has better elastic modulus and yield strength, and the prepared meltblown fabric has higher creep resistance, which makes the meltblown fiber web have stable support performance. It does not easily deform under long-term storage and high temperature, and the fixing firmness between fibers is improved. The impact resistance and heat distortion temperature are balanced, thereby improving the filtration efficiency. Furthermore, by selecting α-crystalline polypropylene with an MFI of 400-1200 g / 10min and a melt index ≥1500 g / 10min, the fusion with polyvinyl acetate and polybutene can be improved, which improves the fluidity of the meltblown fiber and allows the fiber to achieve higher fineness and uniformity.

[0031] Secondly, this application provides a method for preparing meltblown nonwoven fabric, comprising the following steps:

[0032] Polypropylene, polyvinyl acetate, polybutene, electret masterbatch and other raw materials are mixed, melt-extruded to form a molten polymer and sprayed out to form fibers. After cooling, it becomes the meltblown fabric.

[0033] Furthermore, the preparation methods of meltblown nonwoven fabric include:

[0034] S11: Polypropylene, polyvinyl acetate, polybutene, electret masterbatch and other raw materials are mixed to form a mixture;

[0035] S12: The mixture is melt-extruded to form a molten polymer;

[0036] S13: Molten polymer is filtered and conveyed to the meltblown die head;

[0037] S14: The polymer sprayed from the meltblown die head is drawn by hot air at a speed of 30 km / min and shaped into fibers.

[0038] S15: The fiber is cooled and solidified by cold air, which is the meltblown fabric.

[0039] Preferably, the method for preparing meltblown nonwoven fabric includes:

[0040] S11: Grind polypropylene, polyvinyl acetate, polybutene, electret masterbatch, fiber agent, and additives to a particle size ≤3mm and mix them to form a mixture;

[0041] S12: Raw materials are melted and extruded to form a molten polymer;

[0042] S13: Molten polymer is filtered and conveyed to the meltblown die head;

[0043] S14: The polymer sprayed from the meltblown die head is drawn by hot air at a speed of 30 km / min and shaped into fibers.

[0044] S15: The fiber is cooled and solidified by cold air, which is the meltblown fabric.

[0045] By adopting the above technical solution, the raw materials are ground to a particle size of ≤3mm before extrusion, which results in good dispersion of the melt and prevents crystallization. Furthermore, when the meltblown die sprays out the fibers, hot air is used to pull the fibers at a speed of 30km / min, which prevents fly waste. This results in suitable fineness of the meltblown fibers, reduced porosity, enhanced capture ability of the fiber web, increased filtration efficiency, and maintained stability of the meltblown fabric fiber web.

[0046] Thirdly, the method for preparing the odor-resistant mask provided in this application includes the following steps:

[0047] S1: Meltblown fabric production;

[0048] S2: Three-layer composite material SMS generation:

[0049] S21: Spunbond fabric is made from spunbond fabric raw materials;

[0050] S22: Two layers of spunbond fabric are bonded to both sides of meltblown fabric to obtain a three-layer composite material SMS.

[0051] S3: Three-layer composite material SMS is wound up and cut into sheets;

[0052] S4: Sew on the nose clip, heat-fix the ear clips, cut the seam edge and press the sheet to obtain the mask.

[0053] By adopting the above technical solution, a three-layer composite material SMS is formed by hot-rolling and bonding spunbond fabric to meltblown fiber through a single point bonding, or by first bonding the produced spunbond fabric and meltblown fabric together and then bonding the two layers of spunbond fabric to both sides of the meltblown fabric through lamination or other hot-rolling bonding methods. The preparation is simple and conducive to mass production.

[0054] Fourthly, the masks prepared in this application have low air resistance and are comfortable to wear, making them suitable for children. They are less likely to cause breathing difficulties leading to insufficient blood gas concentration or even damage to the respiratory system, and are beneficial to the development of children's cardiopulmonary function.

[0055] In summary, this application includes at least one of the following beneficial technical effects:

[0056] 1. Adding polyvinyl acetate and polybutene can correspondingly increase the toughness and plasticity of polypropylene fibers, improve the fluidity of the melt-blown fibers, and produce high fineness, small and uniform pores, high overlap, and improved support performance of the meltblown fiber web per unit area. Thus, even when the meltblown cloth is thin, it can achieve a good filtration effect. Adding electret masterbatch can improve the fiber adsorption and increase its adsorption capacity for particulate matter and bacteria. Due to the improved adsorption capacity, the prepared meltblown fiber web still has excellent adsorption effect under low density and low air resistance.

[0057] 2. The raw materials are ground and then extruded, which results in good dispersion of the melt and prevents crystallization. When the meltblown die sprays out the fibers, hot air is used to pull the fibers at a speed of 30 km / min, which prevents fly shavings from easily occurring. This results in suitable fineness of meltblown fibers, reduced porosity, enhanced capture ability of the fiber web, increased filtration efficiency, and maintained stability of the meltblown fiber web.

[0058] 3. The mask prepared in this application has low air resistance and is comfortable to wear, making it suitable for children. It is less likely to cause breathing difficulties, resulting in insufficient blood gas concentration or even damage to the respiratory system, and is beneficial to the development of children's cardiopulmonary function. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the production process of this application;

[0060] Figure 2This is a schematic diagram of the production process for meltblown nonwoven fabric in this application;

[0061] Figure 3 This is a schematic diagram of the production process of the three-layer composite material SMS in this application. Detailed Implementation

[0062] The present application will be further described in detail below with reference to the embodiments. The following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the application. Unless otherwise specified, specific conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the methods used are conventional methods known in the art, and the consumables and reagents used are commercially available. Unless otherwise stated, the technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be applied to this application.

[0063] The amount of each component added in the following examples and comparative examples is in kg.

[0064] Example

[0065] Examples 1-3

[0066] The polypropylene used in the following examples is β-crystalline isotactic polypropylene with an MFI of 400–1200 g / 10 min and a melt flow index ≥1500 g / 10 min; the polyvinyl acetate is 99.6% pure polyvinyl acetate; the polybutene, CasNo: 9003-28-5, was purchased from Hubei Enxing Biotechnology Co., Ltd.; the electret masterbatch is commercially available with a bulk density of 0.50–0.80 g / cm³. 3 Electret masterbatch.

[0067] Examples 1-3 each provide a mask.

[0068] The preparation method of the masks in Examples 1-3 includes the following steps:

[0069] The difference between the above embodiments lies in the weight proportions of each component in the mask, as shown in Table 1.

[0070] Table 1: Composition of each component in the masks provided in Examples 1-3

[0071] Polyvinyl acetate polypropylene Polybutene electret masterbatch Example 1 12 41 19 1.5 Example 2 18 31 23 5 Example 3 15 35 21 3

[0072] The preparation method of the masks in Examples 1-3 includes the following steps:

[0073] S1: Meltblown fabric production:

[0074] S11: Polypropylene, polyvinyl acetate, polybutene, and electret masterbatch are metered and mixed to form raw materials;

[0075] S12: Raw materials are fed into a screw extruder and melted to form a molten polymer;

[0076] S13: The molten polymer is conveyed to the filter for filtration and then pumped to the meltblown die head via a metering pump;

[0077] S14: High-speed hot air flow is used to stretch the polymer melt stream extruded from the spinneret of the meltblown die head. The hot air is drawn at a speed of 30 km / min. After the polymer is drawn and shaped, it forms fibers.

[0078] S15: After being cooled by cold air, the fibers are laid on the take-up roller and solidified to form the meltblown fabric;

[0079] S2: Three-layer composite material SMS generation:

[0080] S21: The spunbond fabric raw material is melted and extruded by an extruder and then processed into spunbond fibers by two spinnerets. The two layers of spunbond fibers are sprayed onto both sides of the meltblown fabric to form a three-layer fiber web structure.

[0081] S22: The three-layer fiber web structure is moved to the hot rolling mill by a web laying machine and hot-rolled and bonded to obtain the three-layer composite material SMS;

[0082] S3: The three-layer composite material SMS is wound up by a winding machine and then cut into a predetermined shape by a slitting machine;

[0083] S4: Sew on the nose clip, heat-fix the ear clips, cut the seam edge and press the sheet to obtain the mask.

[0084] The properties of the melt polymer in step S12 above are tested as follows:

[0085] Table 2: Performance Tests of Melt Polymers Obtained from S12 in Examples 1-3

[0086]

[0087] Examples 4-8

[0088] Examples 4-8 each provide a mask.

[0089] The difference between the above embodiments and Embodiment 3 is that the mask preparation in Embodiments 4-8 also includes the addition of a fiber agent, which includes one or two of polylactic acid and cuprammonium fiber. The specific addition amounts are shown in Table 3 below.

[0090] The preparation method of the masks in Examples 4-8 includes the following steps:

[0091] S1: Meltblown fabric production:

[0092] S11: Select fiber agent, polypropylene, polyvinyl acetate, polybutene, and electret masterbatch and mix them in a metered manner to form raw materials;

[0093] S12: Raw materials are fed into a screw extruder and melted to form a molten polymer;

[0094] S13: The molten polymer is conveyed to the filter for filtration and then pumped to the meltblown die head via a metering pump;

[0095] S14: High-speed hot air flow is used to stretch the polymer melt stream extruded from the spinneret of the meltblown die head. The hot air is drawn at a speed of 30 km / min. After the polymer is drawn and shaped, it forms fibers.

[0096] S15: After being cooled by cold air, the fibers are laid on the take-up roller and solidified to form the meltblown fabric;

[0097] S2: Three-layer composite material SMS generation:

[0098] S21: The spunbond fabric raw material is melted and extruded by an extruder and then processed into spunbond fibers by two spinnerets. The two layers of spunbond fibers are sprayed onto both sides of the meltblown fabric to form a three-layer fiber web structure.

[0099] S22: The three-layer fiber web structure is moved to the hot rolling mill by a web laying machine and hot-rolled and bonded to obtain the three-layer composite material SMS;

[0100] S3: The three-layer composite material SMS is wound up by a winding machine and then cut into a predetermined shape by a slitting machine;

[0101] S4: Sew on the nose clip, heat-fix the ear clips, cut the seam edge and press the sheet to obtain the mask.

[0102] Table 3: Composition of each component in the masks provided in Examples 3-8

[0103]

[0104] Examples 9-11

[0105] Examples 9-11 each provide a mask.

[0106] The difference between the above embodiments and Embodiment 8 is that the mask preparation in Embodiments 9-11 also includes additives, which are composed of glyceryl trihydroxy stearate, calcium ricinoleate, and sorbitol as shown in Table 4.

[0107] Table 4: Composition of each component of the additive in the masks provided in Examples 8-11

[0108]

[0109] The method for preparing the masks in Examples 9-11 includes the following steps:

[0110] S1: Meltblown fabric production:

[0111] S11: Select fiber agent, polypropylene, polyvinyl acetate, and polybutene, and add electret masterbatch for metered mixing to form raw materials;

[0112] S12:

[0113] S121: Add glyceryl trihydroxystearate, calcium ricinoleate, and sorbitol to the raw materials and stir evenly to obtain the stirred raw materials;

[0114] S122: Stirred raw materials are fed into a screw extruder and melted to form a molten polymer;

[0115] S13: The molten polymer is conveyed to the filter for filtration and then pumped to the meltblown die head via a metering pump;

[0116] S14: High-speed hot air flow is used to stretch the polymer melt stream extruded from the spinneret of the meltblown die head. The hot air is drawn at a speed of 30 km / min. After the polymer is drawn and shaped, it forms fibers.

[0117] S15: After being cooled by cold air, the fibers are laid on the take-up roller and solidified to form the meltblown fabric;

[0118] S2: Three-layer composite material SMS generation:

[0119] S21: The spunbond fabric raw material is melted and extruded by an extruder and then processed into spunbond fibers by two spinnerets. The two layers of spunbond fibers are sprayed onto both sides of the meltblown fabric to form a three-layer fiber web structure.

[0120] S22: The three-layer fiber web structure is moved to the hot rolling mill by a web laying machine and hot-rolled and bonded to obtain the three-layer composite material SMS;

[0121] S3: The three-layer composite material SMS is wound up by a winding machine and then cut into a predetermined shape by a slitting machine;

[0122] S4: Sew on the nose clip, heat-fix the ear clips, cut the seam edge and press the sheet to obtain the mask.

[0123] Example 12

[0124] Example 12 provides a face mask.

[0125] The difference between Example 12 and Example 11 is that Example 12 also contains 1 kg of clove flower extract (CAS No.: 84961-50-2).

[0126] The method for preparing the mask in Example 12 includes the following steps:

[0127] S1: Meltblown fabric production:

[0128] S11: Select fiber agent, polypropylene, polyvinyl acetate, polybutene, and electret masterbatch and mix them in a metered manner to form raw materials;

[0129] S12:

[0130] S121: Add glyceryl trihydroxystearate, calcium ricinoleate, and sorbitol to the raw materials and stir evenly to obtain the stirred raw materials;

[0131] S122: The raw materials are fed into the screw extruder, and the clove extract is added into the screw extruder under pressure and mixed evenly. The screw extruder is then used to melt and extrude the mixture until a molten polymer is formed.

[0132] S13: The molten polymer is conveyed to the filter for filtration and then pumped to the meltblown die head via a metering pump;

[0133] S14: High-speed hot air flow is used to stretch the polymer melt stream extruded from the spinneret of the meltblown die head. The hot air is drawn at a speed of 30 km / min. After the polymer is drawn and shaped, it forms fibers.

[0134] S15: After being cooled by cold air, the fibers are laid on the take-up roller and solidified to form the meltblown fabric;

[0135] S2: Three-layer composite material SMS generation:

[0136] S21: The spunbond fabric raw material is melted and extruded by an extruder and then processed into spunbond fibers by two spinnerets. The two layers of spunbond fibers are sprayed onto both sides of the meltblown fabric to form a three-layer fiber web structure.

[0137] S22: The three-layer fiber web structure is moved to the hot rolling mill by a web laying machine and hot-rolled and bonded to obtain the three-layer composite material SMS;

[0138] S3: The three-layer composite material SMS is wound up by a winding machine and then cut into a predetermined shape by a slitting machine;

[0139] S4: Sew on the nose clip, heat-fix the ear clips, cut the seam edge and press the sheet to obtain the mask.

[0140] Example 13

[0141] Example 13 provides a face mask.

[0142] The difference between Example 13 and Example 12 is that the polypropylene used in Example 13 is α-crystalline isotactic polypropylene.

[0143] Example 14

[0144] Example 14 provides a face mask.

[0145] The difference between Example 14 and Example 13 is the preparation method.

[0146] The method for preparing the mask in Example 14 includes the following steps:

[0147] S1: Meltblown fabric production

[0148] S11: Select fiber agent, polypropylene, polyvinyl acetate, and polybutene, and add electret masterbatch for metered mixing to form raw materials;

[0149] S12:

[0150] S121: Add glyceryl trihydroxystearate, calcium ricinoleate, and sorbitol to the raw materials and stir evenly to obtain the stirred raw materials;

[0151] S122: The raw materials are ground to a particle size ≤3mm by a grinder and then fed into the screw extruder. S123: The clove extract is pressurized and fed into the screw extruder and mixed evenly. The screw extruder is used to melt and extrude the mixture to form a molten polymer.

[0152] S13: The molten polymer is conveyed to the melt filter for filtration and then pumped to the meltblown die head via a metering pump;

[0153] S14: High-speed hot air flow is used to stretch the polymer melt stream extruded from the spinneret of the meltblown die head. The hot air is drawn at a speed of 30 km / min. After the polymer is drawn and shaped, it forms fibers.

[0154] S15: After being cooled by cold air, the fibers are laid on the take-up roller and solidified to form the meltblown fabric;

[0155] S2: Three-layer composite material SMS generation:

[0156] Spunbond fabric is laminated or bonded to two layers of meltblown fabric to obtain a three-layer composite material SMS;

[0157] S3: The three-layer composite material SMS is wound up by a winding machine and then cut into a predetermined shape by a slitting machine;

[0158] S4: Sew on the nose clip, heat-fix the ear clips, cut the seam edge and press the sheet to obtain the mask.

[0159] Comparative Example

[0160] Comparative Example 1

[0161] The difference between Comparative Example 1 and Example 3 is that polyvinyl acetate was not added during the preparation of the mask.

[0162] Comparative Example 2

[0163] The difference between Comparative Example 2 and Example 3 is that polybutene was not added during the preparation of the mask.

[0164] Performance testing

[0165] 1) Test the bacterial filtration efficiency of the mask according to the test method in T / CDAMEI001-2020 for meltblown nonwoven fabrics used in masks;

[0166] 2) Test the particulate filtration efficiency of the mask by measuring the level of particles removed by meltblown fabric under the conditions specified in GB2626-2019.

[0167] 3) According to the test method of YYT0969-2013, the air resistance of gas exchange on both sides of the mask should not be greater than 49Pa / cm to be considered qualified;

[0168] 4) Test the filtration efficiency change rate of the mask according to the test method in T / CDAMEI001-2020 for meltblown nonwoven fabrics used in masks; among them, the particle filtration efficiency change rate ≤5% and the bacterial filtration efficiency change rate ≤2% are qualified within the validity period (2 years); record the particle filtration efficiency change rate as A, and record the bacterial filtration efficiency change rate as B.

[0169] 5) Test the change rate of filtration efficiency of the mask under high temperature (65℃) conditions, and record it as C;

[0170] 6) Biological evaluation:

[0171] Cytotoxicity was assessed by preparing the extract according to the conditions specified in GB / T 16886.12 and performing the test according to the method in GB / T 16886.5. Skin irritation was assessed by preparing the extract according to the conditions specified in GB / T 16886.12 and performing the animal skin irritation test as specified in GB / T 16886.10. Delayed-type hypersensitivity was assessed by preparing the extract according to the conditions specified in GB / T 16886.12 and performing the maximum dose test for delayed-type hypersensitivity as specified in GB / T 16886.10.

[0172] 7) Non-sterile masks shall be tested according to the methods specified in Appendix B of GB15979 to detect their microbiological indicators;

[0173] 8) Visual inspection:

[0174] 6.2.1 Appearance quality: Randomly select 10 samples for testing and visual inspection; the test light should be normal natural light, and if fluorescent lamps are used, the illuminance should not be less than 600 lx.

[0175] The basic quality requirements test results of the masks prepared according to the specification of 50g / ㎡ in Example 14 are shown in Table 5 below:

[0176] Table 5: Basic quality requirements for the masks prepared in Example 14

[0177]

[0178] The performance test results of the masks in Examples 1-14 and Comparative Examples 1-2 are as follows:

[0179] Table 6: Performance characteristics of the masks in Examples 1-14 and Comparative Examples 1-2

[0180]

[0181] The change rate of particulate filtration efficiency was recorded as A (%), the change rate of bacterial filtration efficiency was recorded as B (%), and the change rate of filtration efficiency under high temperature (65℃) conditions was recorded as C (%). The test results of each change rate are as follows:

[0182] Table 7: Rates of change of various items for masks in Examples 1-14 and Comparative Examples 1-2

[0183]

[0184]

[0185] Results Analysis

[0186] The following detailed description of this application is based on the experimental data provided in Tables 1-7.

[0187] Based on Examples 1-14 and Table 6, the masks prepared using polyvinyl acetate, polypropylene, polybutene, and electret masterbatch have an air resistance below 30 Pa, a bacterial filtration efficiency of 92.5-99.4%, a particulate matter filtration efficiency of 92.4-99.3%, and a total bacterial count of 23-63 CFU / g without sterilization, with no detected fungal colonies, which is far lower than the relevant standards of 200 CFU / g and 100 CFU / g. The masks exhibit good bacterial and particulate matter filtration efficiency and low air resistance.

[0188] Based on Examples 1-14 and Table 7, the masks prepared in Examples 1-14 can control the change rate of particulate matter filtration efficiency within 5% over time, the change rate of bacterial filtration efficiency within 2% over time, and the change rate of high-temperature bacterial filtration efficiency within 2.5% over time. They have stable performance, can withstand high temperatures, and have stable filtration effect within a certain period after production.

[0189] Examples 1-3 investigated the effects of the composition and ratio of polyvinyl acetate, polypropylene, polybutene, and electret masterbatch on the prepared masks. Although the total bacterial count and total fungal count remained unchanged, the mask prepared in Example 3 had lower air resistance and higher bacterial filtration efficiency and particulate filtration efficiency. Therefore, Example 3 is the preferred example.

[0190] Using Example 4 as a control, Examples 4-8 investigated the effects of polylactic acid and cupro fiber on the prepared masks. When polylactic acid or cupro fiber was added alone, the air resistance was reduced by 2.6 units, and the bacterial filtration efficiency and particulate filtration efficiency were improved by 2 units. Moreover, the change rate of particulate filtration efficiency over time (A) was greater than 3.5%, the change rate of bacterial filtration efficiency over time (B) was greater than 1.6%, and the change rate of high-temperature bacterial filtration efficiency (C) was greater than 1.82%. Example 8 is the preferred example.

[0191] By mixing polylactic acid (PLA) and cupro fiber, the air resistance is reduced more significantly after mixing than when adding them separately. Furthermore, the bacterial filtration efficiency and particulate filtration efficiency are both increased to over 96%, with the change rate of particulate filtration efficiency over time (A) below 3%, the change rate of bacterial filtration efficiency over time (B) below 1.6%, and the change rate of high-temperature bacterial filtration efficiency (C) above 1.4%. This demonstrates that the mixing of PLA and cupro fiber has a synergistic effect on the air resistance, change rate of particulate filtration efficiency over time (A), change rate of bacterial filtration efficiency over time (B), and change rate of high-temperature bacterial filtration efficiency (C) of meltblown fabric, enhancing the long-term stability and high-temperature resistance of the mask.

[0192] Using Example 8 as a control, Examples 8-11 investigated the effects of different additive ratios on the prepared masks. When additives were added, the changes in the mask's airflow resistance and the rate of change in high-temperature bacterial filtration efficiency (C) were not significant, but the total bacterial count decreased, and the bacterial filtration efficiency and particulate filtration efficiency both increased to over 97%. Moreover, the rate of change in particulate filtration efficiency (A) over time was below 1.7%, and the rate of change in bacterial filtration efficiency (B) over time was below 1.2%. It can be seen that the additives can reduce the total bacterial count in the prepared masks, improve the bacterial filtration efficiency and particulate filtration efficiency, and have a positive impact on the rate of change in particulate filtration efficiency (A) and the rate of change in bacterial filtration efficiency (B) over time. Considering all factors, when glyceryl trihydroxy stearate, calcium ricinoleate, and sorbitol were added in a ratio of 3:4:3, the meltblown fabric exhibited better performance in all aspects. Example 11 is the preferred example.

[0193] Compared with Example 11, Example 12 investigated the effect of clove extract on the prepared mask. Although the changes in high-temperature bacterial filtration efficiency (C), time-dependent bacterial filtration efficiency (B), and air resistance were not significant after the addition of clove extract, the total bacterial count of the prepared mask was further reduced to 23 CFU / g, and the bacterial filtration efficiency and particulate matter filtration efficiency were improved to a certain extent. This may be because clove extract can inhibit the growth and reproduction of mold in the meltblown fabric production process, thus the prepared mask has a good deodorizing effect.

[0194] Using Example 12 as a control, Example 13 investigated the effect of polypropylene properties on the prepared masks. After selecting α-type isotactic polypropylene with an MFI of 400–1200 g / 10 min and a melt index ≥1500, the prepared masks had reduced air resistance, and the bacterial filtration efficiency and particulate filtration efficiency were both increased to over 99%. The change rate of particulate filtration efficiency over time (A), the change rate of bacterial filtration efficiency over time (B), and the change rate of high-temperature bacterial filtration efficiency (C) decreased to below 1%. This may be because the fibers prepared from α-type isotactic polypropylene with an MFI of 400–1200 g / 10 min and a melt index ≥1500 achieve a higher fineness, thus improving the filtration effect. The prepared meltblown fabric has higher creep resistance, which gives the meltblown fiber web stable support properties, preventing it from easily deforming during long-term storage and at high temperatures, and improving the fixation strength between fibers.

[0195] Compared with Example 13, Example 14 investigated the effect of the preparation method on the prepared mask. After the raw material was ground to a particle size of <3mm by a grinder and then extruded, and the fiber was sprayed out by the meltblown die, hot air was used to pull the fiber at a speed of 30km / min. The ventilation resistance of the prepared mask was reduced to below 16Pa, and the change rate of particulate matter filtration efficiency (A), the change rate of bacterial filtration efficiency (B), and the change rate of high-temperature bacterial filtration efficiency (C) over time were reduced to below 1%. This may be because after the raw material is ground, the dispersion performance of the melt is good and crystallization does not easily occur.

[0196] Using Example 3 as a control, Comparative Examples 1 and 2 investigated the effects of not adding polyvinyl acetate and not adding polybutene on the resulting masks. Among them, the performance of other parts of Comparative Examples 1 and 2 met the standards, but the ventilation resistance was ≥67Pa, and the change rate of bacterial filtration efficiency over time (B) was above 4.5% and the change rate of high-temperature bacterial filtration efficiency (C) reached above 3.5%. The ventilation resistance of the masks was poor, the wearing experience was not good, and the stability of the masks was not good.

[0197] Furthermore, as shown in Table 5, the mask prepared in Example 3 has high resistance to breakage, low skin irritation, and a delayed-type hypersensitivity reaction level of 1. Therefore, it is suitable for children's daily protective wear, and can take into account both protective performance and comfort performance. Children will not experience insufficient blood gas concentration or damage to the respiratory system due to breathing difficulties when wearing it for a long time, which is beneficial to the development of children's cardiopulmonary function.

[0198] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A meltblown nonwoven fabric, characterized in that, Made from the following raw materials in parts by weight: 12-15 parts of polyvinyl acetate 31-41 parts of polypropylene 19-23 parts of polybutene 1.5-5 parts electret masterbatch; The raw materials for preparing the meltblown fabric also include 20 parts by weight of a fiber agent, which is composed of polylactic acid and cuprammonium fiber in a weight ratio of (6-13):(7-14).

2. The meltblown fabric according to claim 1, characterized in that: The raw materials for preparing the meltblown fabric also include additives, which consist of lubricants, stabilizers, and monosaccharides; The lubricant is one or more of glyceryl trihydroxystearate, oxidized polyethylene wax, Fischer-Tropsch wax, and stearic acid; The stabilizer is one or more of cadmium ricinoleate, calcium stearate, calcium ricinoleate, and magnesium stearate. The monosaccharide is one or both of glucose and sorbitol.

3. The meltblown fabric according to claim 2, characterized in that: The additive is composed of glyceryl trihydroxy stearate, calcium ricinoleate, and sorbitol in a weight ratio of (0.5-4):(1-4):(0.5-2).

4. The meltblown fabric according to claim 1, characterized in that: The raw materials for preparing the meltblown fabric also include 0.5-1.2 parts by weight of clove flower extract.

5. The meltblown fabric according to claim 1, characterized in that: The polypropylene is α-crystalline isotactic polypropylene or β-crystalline isotactic polypropylene.

6. A process for preparing meltblown nonwoven fabric according to any one of claims 1-5, characterized in that, Includes the following steps: Polypropylene, polyvinyl acetate, polybutene, electret masterbatch and other raw materials are mixed, melt-extruded to form a molten polymer and sprayed out to form fibers. After cooling, it becomes the meltblown fabric.

7. The preparation process of meltblown nonwoven fabric according to claim 6, characterized in that, Includes the following steps: Polypropylene, polyvinyl acetate, polybutene, electret masterbatch, fiber agent, and additives are ground to a particle size of ≤3mm, mixed evenly with other raw materials, melt-extruded to form a molten polymer, and sprayed out to form fibers. After cooling, it becomes the meltblown fabric.

8. An odor-resistant face mask, characterized in that, It is prepared from the meltblown fabric described in any one of claims 1-5.

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