Chemical-optical combined self-sterilizing mask filter element and preparation method thereof

Abstract

The application discloses a chemical-optical combined self-killing mask filter element and a preparation method. The filter element is composed of polypropylene, zinc oxide and polydopamine-piperidine nanoparticles. Polypropylene and nano zinc oxide particles are uniformly stirred at 190 DEG C as raw materials to prepare a mask filter element substrate by using a fused deposition 3D printing technology. Then, the substrate is soaked in a 50 mg / mL zinc chloride and 25 mg / mL urea aqueous solution, and a hydrothermal reaction is carried out at 90 DEG C for 2 hours, so that zinc oxide is grown on the surface of the substrate. After drying, the polydopamine-piperidine nanoparticles are sprayed on the surface of the sample by using a spraying technology, and a chemical-optical combined self-killing mask is prepared.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical materials, and particularly relates to a chemical-optical combined self-killing mask filter element and a preparation method. BACKGROUND

[0002] With the development of industry, air pollution is becoming more and more serious, which has become the main inducement of human respiratory related diseases. Masks are the first line of defense for humans against bacteria, viruses, dust, etc. However, it is common in daily life to repeatedly use masks. The current protection mechanism of masks mainly depends on the filtering and adsorption ability of masks to bacteria, viruses, etc. However, more than 90% of the bacteria adsorbed on the surface of the mask can still maintain a survival time of 8 hours. Therefore, the repeatedly used mask not only loses its protective effect, but also becomes the main medium for disease transmission.

[0003] Polypropylene masks have been widely recognized in the field of medical materials. The current effective method to give masks antibacterial properties is to perform antibacterial coating treatment on the surface of the existing polypropylene-based mask. Chinese patent CN202010119362 discloses an anti-virus mask that uses silver ions or silver-copper ions to kill viruses. Chinese patent CN202010128690.4 discloses an antibacterial and anti-virus mask modified with silver, carbon dioxide, zinc oxide, bismuth tungstate, silicon dioxide, chitosan, or quaternary ammonium salt. Chinese patent CN202110998957.X discloses a polydopamine-modified core-shell titanium dioxide@oxidized chitosan nanoparticle coating modified polypropylene melt-blown cloth, which uses titanium dioxide@oxidized chitosan nanoparticles to photocatalytically kill viruses.

[0004] However, the polypropylene mask coating prepared by these methods has low bonding strength between the coating and the polypropylene substrate, and cannot quickly and completely eliminate bacteria on the surface of the mask. SUMMARY

[0005] In view of the above problems, the present application takes polypropylene masks as the target, first adds zinc oxide seeds directly into the polypropylene raw material to prepare a mask filter element substrate using 3D printing technology, and grows a layer of zinc oxide on the surface of the substrate by hydrothermal method using the seeds in the substrate as the origin, thereby solving the problem of the bonding strength of zinc oxide with the mask. Secondly, the synthesized polydopamine-piperidine nanoparticles with excellent light-heat conversion efficiency are sprayed on the surface of the zinc oxide to obtain a chemical-optical combined self-killing mask filter element. On the one hand, the high temperature formed by the light-heat conversion of polydopamine-piperidine is used to kill bacteria on the surface of the mask. On the other hand, zinc oxide is used to absorb ultraviolet light to generate free radicals to kill bacteria on the surface of the mask. Based on these excellent properties, the present application provides a chemical-optical combined self-killing recyclable mask and a preparation method.

[0006] The application provides a chemical-optical combined self-killing mask filter element, which is composed of polypropylene, zinc oxide and polydopamine-piperidine.

[0007] Further, the weight percentage of the polypropylene is 87.5-98.4%, the weight percentage of the zinc oxide is 1.5-10%, and the weight percentage of the polydopamine-piperidine nanoparticles is 0.1-2.5%.

[0008] The application also provides a preparation method of the chemical-optical combined self-killing mask filter element, which comprises the following steps:

[0009] Step one: polydopamine-piperidine nanoparticles are prepared by the reaction of 2,2,6,6-tetramethylpiperidine oxide and dopamine hydrochloride.

[0010] Step two: polypropylene and nano-zinc oxide are stirred and uniformly mixed under a melting condition as raw materials, a mask filter element substrate is obtained by using a fused deposition 3D printing technology, and then the substrate is soaked in a zinc chloride and urea aqueous solution to perform a hydrothermal reaction, so that zinc oxide is grown on the surface of the substrate.

[0011] Step three: the product obtained in step two is dried, and the polydopamine-piperidine nanoparticles obtained in step one are coated on the surface of the dried sample by using a spraying technology, so that the chemical-optical combined self-killing mask filter element is prepared.

[0012] Beneficial effects:

[0013] 1. The chemical-optical combined self-killing mask filter element provided by the application firstly adds zinc oxide crystal seeds in the polypropylene raw material to prepare a mask filter element substrate by using a 3D printing technology, and a layer of zinc oxide is grown on the surface of the substrate by taking the crystal seeds in the substrate as the original point, so that the problem of the bonding force between the zinc oxide and the mask is solved.

[0014] 2. The self-killing mask filter element provided by the application has a chemical and optical dual-killing mechanism, on one hand, high temperature formed by the photo-thermal conversion of the polydopamine-piperidine is used to kill bacteria on the surface of the mask, and on the other hand, free radicals generated by the absorption of ultraviolet light by the zinc oxide are used to kill bacteria on the surface of the mask, so that the effect of rapid and complete killing can be achieved.

[0015] 3. The operation is convenient, and the application is suitable for large-scale industrial production and has a wide application prospect. DETAILED DESCRIPTION

[0016] Figure 1 : The powder X-ray diffraction pattern of the polypropylene mask filter element prepared in Example 13 (a control sample) and the powder X-ray diffraction pattern of the chemical-optical combined self-killing mask filter element prepared in Example 5.

[0017] Figure 2Thermogravimetric analysis of the powder of the raw material used for the polypropylene mask filter cartridge prepared in Example 13 (control sample) and the chemical-optical combined self-sterilizing mask filter cartridge prepared in Example 5.

[0018] Figure 3 Optical microscope photograph (A), scanning electron microscope photograph (B), and partial enlarged view (C) of the chemical-optical combined self-sterilizing mask filter cartridge prepared in Example 5.

[0019] Figure 4 Infrared spectrum of the polypropylene mask filter cartridge prepared in Example 13 (control sample) and the chemical-optical combined self-sterilizing mask filter cartridge prepared in Example 5.

[0020] Figure 5 Peeling stress-strain curve of the coating of the chemical-optical combined self-sterilizing mask filter cartridge prepared in Example 5.

[0021] Figure 6 Temperature change of the chemical-optical combined self-sterilizing mask filter cartridges prepared in Examples 2 to 12 after irradiation with 1.5 w / cm 2 , 808 nm infrared light source for different time.

[0022] Figure 7 Graphical representation of the antibacterial property of the polypropylene mask filter cartridge prepared in Example 13 (control sample), the polypropylene / zinc oxide mask filter cartridge prepared in Example 14 (control sample), and the chemical-optical combined self-sterilizing mask filter cartridge prepared in Example 5 under light irradiation by the zone of inhibition method. DETAILED DESCRIPTION

[0023] The present application is further described in the following examples, which are provided for further illustrating the present application and are not intended to limit the scope of the present application. After reading the present disclosure, those skilled in the art will appreciate modifications or alterations to the present application. Such modifications or alterations are intended to be within the scope of the present application.

[0024] Example 1

[0025] Dopamine hydrochloride solution (10 mg / mL) was rapidly injected into 2,2,6,6-tetramethylpiperidine oxide solution (5 mg / mL) at a volume ratio of 4:1. The reaction was stirred at room temperature for 18 h, and then the precipitate was collected by centrifugation at 2000 rpm for 10 min. After freeze-drying, polydopamine-piperidine nanoparticles were obtained.

[0026] Example 2

[0027] A polypropylene with a weight fraction of 92.5% and nano-zinc oxide particles with a weight fraction of 3.5% were stirred and mixed uniformly under a melting condition at 190°C as raw materials to obtain a mask filter element substrate by using a fused deposition 3D printing technology. The printing conditions were: a melting temperature of 190°C, a printing pillow size of 0.5 mm, and a printing speed of 10 mm / s.

[0028] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and a hydrothermal reaction was performed at 90°C for 2 hours. The weight fraction of zinc oxide grown on the surface was 1.5%. After drying, the sample was sprayed with polydopamine-piperidine nanoparticles with a weight fraction of 2.5% obtained in Example 1 on the surface by using a spraying technology to obtain a chemical-optical combined self-sterilizing mask filter element.

[0029] Example 3

[0030] A polypropylene with a weight fraction of 93.5% and nano-zinc oxide particles with a weight fraction of 3.5% were stirred and mixed uniformly under a melting condition at 190°C as raw materials to obtain a mask filter element substrate by using a fused deposition 3D printing technology. The printing conditions were: a melting temperature of 190°C, a printing pillow size of 0.5 mm, and a printing speed of 10 mm / s.

[0031] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and a hydrothermal reaction was performed at 90°C for 2 hours. The weight fraction of zinc oxide grown on the surface was 1.5%. After drying, the sample was sprayed with polydopamine-piperidine nanoparticles with a weight fraction of 1.5% obtained in Example 1 on the surface by using a spraying technology to obtain a chemical-optical combined self-sterilizing mask filter element.

[0032] Example 4

[0033] A polypropylene with a weight fraction of 94% and nano-zinc oxide particles with a weight fraction of 3.5% were stirred and mixed uniformly under a melting condition at 190°C as raw materials to obtain a mask filter element substrate by using a fused deposition 3D printing technology. The printing conditions were: a melting temperature of 190°C, a printing pillow size of 0.5 mm, and a printing speed of 10 mm / s.

[0034] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and a hydrothermal reaction was performed at 90°C for 2 hours. The weight fraction of zinc oxide grown on the surface was 1.5%. After drying, the sample was sprayed with polydopamine-piperidine nanoparticles with a weight fraction of 1% obtained in Example 1 on the surface by using a spraying technology to obtain a chemical-optical combined self-sterilizing mask filter element.

[0035] Example 5

[0036] The polypropylene with a weight fraction of 94.5% and the nano-zinc oxide particles with a weight fraction of 3.5% were stirred and uniformly mixed under the melting condition at 190°C as raw materials to obtain a mask filter element substrate by using the fused deposition 3D printing technology. The printing conditions were as follows: the melting temperature was 190°C, the printing pillow size was 0.5 mm, and the printing speed was 10 mm / s.

[0037] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and was subjected to hydrothermal reaction at 90°C for 2 hours, so that zinc oxide with a weight fraction of 1.5% was grown on the surface. After drying, the sample was sprayed with the polydopamine-piperidine nanoparticles with a weight fraction of 0.5% obtained in Example 1 on the surface by using the spraying technology, to obtain a chemical-optical combined self-sterilizing mask filter element.

[0038] Example 6

[0039] The polypropylene with a weight fraction of 94.9% and the nano-zinc oxide particles with a weight fraction of 3.5% were stirred and uniformly mixed under the melting condition at 190°C as raw materials to obtain a mask filter element substrate by using the fused deposition 3D printing technology. The printing conditions were as follows: the melting temperature was 190°C, the printing pillow size was 0.5 mm, and the printing speed was 10 mm / s.

[0040] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and was subjected to hydrothermal reaction at 90°C for 2 hours, so that zinc oxide with a weight fraction of 1.5% was grown on the surface. After drying, the sample was sprayed with the polydopamine-piperidine nanoparticles with a weight fraction of 0.1% obtained in Example 1 on the surface by using the spraying technology, to obtain a chemical-optical combined self-sterilizing mask filter element.

[0041] Example 7

[0042] The polypropylene with a weight fraction of 87.5% and the nano-zinc oxide particles with a weight fraction of 7% were stirred and uniformly mixed under the melting condition at 190°C as raw materials to obtain a mask filter element substrate by using the fused deposition 3D printing technology. The printing conditions were as follows: the melting temperature was 190°C, the printing pillow size was 0.5 mm, and the printing speed was 10 mm / s.

[0043] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and was subjected to hydrothermal reaction at 90°C for 2 hours, so that zinc oxide with a weight fraction of 3% was grown on the surface. After drying, the sample was sprayed with the polydopamine-piperidine nanoparticles with a weight fraction of 2.5% obtained in Example 1 on the surface by using the spraying technology, to obtain a chemical-optical combined self-sterilizing mask filter element.

[0044] Example 8

[0045] The polypropylene with a weight fraction of 89% and the nano zinc oxide particles with a weight fraction of 7% were stirred and mixed uniformly under the melting condition at 190 °C as raw materials to obtain the mask filter element substrate by using the fused deposition 3D printing technology. The printing conditions were as follows: the melting temperature was 190 °C, the printing pillow size was 0.5 mm, and the printing speed was 10 mm / s.

[0046] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and was subjected to hydrothermal reaction at 90 °C for 2 hours, so that the zinc oxide with a weight fraction of 3% was grown on the surface. After drying, the sample was sprayed with the polydopamine-piperidine nanoparticles with a weight fraction of 1% obtained in Example 1 on the surface by using the spraying technology, so as to obtain the chemical-optical combined self-sterilizing mask filter element.

[0047] Example 9

[0048] The polypropylene with a weight fraction of 89.9% and the nano zinc oxide particles with a weight fraction of 7% were stirred and mixed uniformly under the melting condition at 190 °C as raw materials to obtain the mask filter element substrate by using the fused deposition 3D printing technology. The printing conditions were as follows: the melting temperature was 190 °C, the printing pillow size was 0.5 mm, and the printing speed was 10 mm / s.

[0049] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and was subjected to hydrothermal reaction at 90 °C for 2 hours, so that the zinc oxide with a weight fraction of 3% was grown on the surface. After drying, the sample was sprayed with the polydopamine-piperidine nanoparticles with a weight fraction of 0.1% obtained in Example 1 on the surface by using the spraying technology, so as to obtain the chemical-optical combined self-sterilizing mask filter element.

[0050] Example 10

[0051] The polypropylene with a weight fraction of 96% and the nano zinc oxide particles with a weight fraction of 1% were stirred and mixed uniformly under the melting condition at 190 °C as raw materials to obtain the mask filter element substrate by using the fused deposition 3D printing technology. The printing conditions were as follows: the melting temperature was 190 °C, the printing pillow size was 0.5 mm, and the printing speed was 10 mm / s.

[0052] Then, the mask filter element substrate was soaked in an aqueous solution containing 50 mg / mL zinc chloride and 25 mg / mL urea, and was subjected to hydrothermal reaction at 90 °C for 2 hours, so that the zinc oxide with a weight fraction of 0.5% was grown on the surface. After drying, the sample was sprayed with the polydopamine-piperidine nanoparticles with a weight fraction of 2.5% obtained in Example 1 on the surface by using the spraying technology, so as to obtain the chemical-optical combined self-sterilizing mask filter element.

[0053] Example 11

[0054] Polypropylene with weight fraction of 97.5% and nano-zinc oxide particles with weight fraction of 1% were stirred and mixed under 190℃ melting condition as raw materials to obtain the mask filter core substrate by using the fused deposition 3D printing technology. The printing conditions were: melting temperature 190℃, printing pillow size 0.5mm, printing speed 10mm / s.

[0055] Then, the mask filter core substrate was soaked in an aqueous solution containing 50mg / mL zinc chloride and 25mg / mL urea, and hydrothermally reacted at 90℃ for 2 hours. The weight fraction of zinc oxide grown on the surface was 0.5%. After drying, the sample was sprayed with polydopamine-piperidine nanoparticles with weight fraction of 1% obtained in Example 1 on the surface by using the spraying technology, to obtain the chemical-optical combined self-sterilizing mask filter core.

[0056] Example 12

[0057] Polypropylene with weight fraction of 98.4% and nano-zinc oxide particles with weight fraction of 1% were stirred and mixed under 190℃ melting condition as raw materials to obtain the mask filter core substrate by using the fused deposition 3D printing technology. The printing conditions were: melting temperature 190℃, printing pillow size 0.5mm, printing speed 10mm / s.

[0058] Then, the mask filter core substrate was soaked in an aqueous solution containing 50mg / mL zinc chloride and 25mg / mL urea, and hydrothermally reacted at 90℃ for 2 hours. The weight fraction of zinc oxide grown on the surface was 0.5%. After drying, the sample was sprayed with polydopamine-piperidine nanoparticles with weight fraction of 0.1% obtained in Example 1 on the surface by using the spraying technology, to obtain the chemical-optical combined self-sterilizing mask filter core.

[0059] Example 13

[0060] Polypropylene with weight fraction of 100% was used to obtain the polypropylene mask filter core by using the fused deposition 3D printing technology. The printing conditions were: melting temperature 190℃, printing pillow size 0.5mm, printing speed 10mm / s.

[0061] Example 14

[0062] Polypropylene with weight fraction of 95% and nano-zinc oxide particles with weight fraction of 3.5% were stirred and mixed under 190℃ melting condition as raw materials to obtain the mask filter core substrate by using the fused deposition 3D printing technology. The printing conditions were: melting temperature 190℃, printing pillow size 0.5mm, printing speed 10mm / s.

[0063] Then, the mask filter core substrate was soaked in an aqueous solution containing 50mg / mL zinc chloride and 25mg / mL urea, and hydrothermally reacted at 90℃ for 2 hours. The weight fraction of zinc oxide grown on the surface was 1.5%. After drying, the sample was sprayed with polydopamine-piperidine nanoparticles with weight fraction of 1% obtained in Example 1 on the surface by using the spraying technology, to obtain the chemical-optical combined self-sterilizing mask filter core.

[0064] From Figure 1 the XRD pattern of the raw material used in Example 5, new peaks appeared at 31.8°, 34.4°, 36.2°, 47.5°, 56.7° and 62.9°, which were consistent with the standard pattern of zinc oxide, indicating that the raw material used in Example 5 was a mixture of polypropylene and zinc oxide. From the thermogravimetric pattern Figure 2 , it can be seen that the polypropylene raw material of Example 13 (control) lost 100% of the sample weight at 435°C, completely combusted. The raw material used in Example 5 lost 95% of the sample weight at 435°C, and the sample weight did not change as the temperature increased, because the zinc oxide contained in the raw material could not be lost by combustion. That is, the zinc oxide content in the raw material of Example 5 was 5%.

[0065] From Figure 3 the photos of the optical microscope (A), it can be seen that the fibers of the chemical-optical combined self-killing mask filter element prepared in Example 5 have uniformly distributed black dot-like structures. From the scanning electron microscope photos (B), it can be seen that the local magnification of the fiber is composed of flaky structures, full of pores. This is because of the zinc oxide formed by hydrothermal reaction. In the local magnification photo (C), it can be seen that there are clusters of 300 nm size particles in the pores. This is because the polydopamine piperidine nanoparticles are embedded in the pores formed by the zinc oxide flaky structure after spraying.

[0066] From Figure 4 , it can be seen that compared with the polypropylene mask filter element of Example 13 (control sample), the chemical-optical combined self-killing mask filter element obtained in Example 5 has characteristic absorption peaks at 1270 cm -1 , 1493 cm -1 , 1620 cm -1 and 3450 cm -1 , corresponding to the C-O, C=C, C=O, N-H and / or OH stretching vibration in the polydopamine molecule, while the characteristic absorption peak of N-O in the piperidine molecule appears at 1366 cm -1 . This is because the chemical-optical combined self-killing mask filter element obtained in Example 5 contains polydopamine piperidine nanoparticles.

[0067] From Figure 5In the present application, the peel stress-strain curve of the surface coating of the chemical-optical combined self-killing mask filter element prepared in Example 5 can be seen that with the increase of displacement, the stress gradually increases, and after reaching equilibrium, the stress-strain changes in a sawtooth shape. This is because the chemical-optical combined self-killing mask filter element obtains a parallel and spaced fiber structure during 3D printing, and during the peel measurement process in one direction, the pores between the fibers cause the stress to decrease. Finally, it can be concluded that the peel strength of the surface coating of the chemical-optical combined self-killing mask filter element is 1.25±0.5kPa, and the shear strength is 112.8±11.2kPa.

[0068] From Figure 6 It can be seen from the present application that the chemical-optical combined self-killing mask filter elements prepared in Examples 2-12 all have light-heat conversion ability, and the temperature of the chemical-optical combined self-killing mask filter element prepared in Example 2 reaches 320℃, the temperature of the chemical-optical combined self-killing mask filter element prepared in Example 7 reaches 348.9℃, and the temperature of the chemical-optical combined self-killing mask filter element prepared in Example 10 reaches 265.3℃ after being irradiated by an 808nm infrared light source for 30s at a power of 1.5w / cm 2 2 The temperatures of the chemical-optical combined self-killing mask filter elements prepared in Examples 3-6, Example 8, Example 9, Example 11 and Example 12 reach 224.6℃, 123.1℃, 98.2℃, 91.5℃, 123.1℃, 81.8℃, 121.5℃ and 80.3℃, respectively, after being irradiated by an 808nm infrared light source for 60s at a power of 1.5w / cm

[0069] Figure 7 In the present application, A and B are the environment of E. coli, and C and D are the environment of S. aureus; B and D are under light conditions, and A and C are under no light conditions. From Figure 7 It can be seen from the present application that the polypropylene mask filter element (control sample) 1 prepared in Example 13 has no bacteriostatic circle around it, proving that the polypropylene mask filter element (control sample) 1 has no antibacterial activity. The polypropylene / zinc oxide mask filter element (control sample) 2 prepared in Example 14 has a bacteriostatic circle around it, proving that the polypropylene / zinc oxide mask filter element prepared in Example 14 has antibacterial activity against both E. coli and S. aureus, and the size of the bacteriostatic circle under light conditions is larger than that under no light conditions. The chemical-optical combined self-killing mask filter element 3 prepared in Example 5 also has a bacteriostatic circle around it, and the size of the bacteriostatic circle is significantly larger than that of the polypropylene / zinc oxide mask filter element prepared in Example 14, and the size of the bacteriostatic circle under light conditions is larger than that under no light conditions. This is because the chemical-optical combined self-killing mask filter element prepared in Example 5 contains polydopamine piperidine, which has light-heat conversion sterilization activity.​

Claims

1. A method for preparing a chemical-optical combined self-sterilizing mask filter element, characterized in that: The mask filter element is composed of polypropylene, zinc oxide and polydopamine-piperidine; the weight percentage of polypropylene is 87.5-98.4%, the weight percentage of zinc oxide is 1.5-10%, and the weight percentage of polydopamine-piperidine nanoparticles is 0.1-2.5%; comprising the following steps: Step one: preparing polydopamine-piperidine nanoparticles by reacting 2,2,6,6-tetramethylpiperidinoxide and dopamine hydrochloride; Step two: stirring and mixing polypropylene and nano-zinc oxide under melting conditions as raw materials, using the fused deposition 3D printing technology to obtain the mask filter element substrate, then soaking it in a zinc chloride and urea aqueous solution for hydrothermal reaction to grow zinc oxide on its surface; Step three: drying the product obtained in step two, and using the spray coating technology to coat the surface of the dried sample with the polydopamine-piperidine nanoparticles obtained in step one, to obtain the chemical-optical combined self-killing mask filter element.

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