KR102402307B1 - Manufacturing method of biodegradable mask using polyvinyl alcohol - Google Patents

Abstract

The present invention relates to a method for manufacturing a biodegradable mask using polyvinyl alcohol, wherein the polyvinyl alcohol can easily manufacture non-woven fabric and be easily decomposed through enzyme decomposition, thereby having excellent environmental protection efficacy.

Description

Manufacturing method of biodegradable mask using polyvinyl alcohol {Manufacturing method of biodegradable mask using polyvinyl alcohol}

The present invention relates to a method for manufacturing a biodegradable mask using polyvinyl alcohol.

Disposable masks, a necessity in the era of COVID-19, are causing serious environmental pollution. 129 billion disposable masks are used every month worldwide, which is said to take 'one second to make, 450 years to decay'. It causes enormous damage to marine life and is a threat to humans as it decomposes into microplastics. Oceans Asia, a Hong Kong NGO marine environment conservation group, has also estimated that 6,240 tons of marine plastic pollutants will increase in the ocean. As such, the problem of waste in masks is so serious that the phrase 'a mask that saves humans and kills the planet' comes out. Since there are many limitations in efforts to alleviate environmental pollution, such as the method of melting masks to make chairs, it is important to solve fundamental problems such as mask ingredients rather than recycling waste masks.

Therefore, the inventors of the present invention have completed the present invention by understanding the severity of environmental pollution exerted by the existing disposable mask, and manufacturing a filter of the mask using a biodegradable plastic material that can reduce environmental pollution.

Republic of Korea Patent Registration No. 10-2313425 (Title of the invention: biodegradable mask or mask filter waste recycling method and product thereof, applicant: Kang Tae-wook and one other person, registration date: October 08, 2021) Republic of Korea Patent Registration No. 10-2138634 (Title of the invention: Biodegradable PLA nonwoven fabric for droplet blocking mask with water repellent properties and manufacturing method thereof, Applicant: Ecole Greentech Co., Ltd., Registration date: July 22, 2020)

An object of the present invention is to provide a method for manufacturing a biodegradable mask using polyvinyl alcohol.

The present invention relates to a method for manufacturing a biodegradable mask using polyvinyl alcohol.

More preferably, the manufacturing method comprises:

(Step 1) preparing a raw material containing polyvinyl alcohol; and,

(Second step) manufacturing a felt by electrospinning the raw material;

may include

The raw material containing polyvinyl alcohol in the first step may be an aqueous solution of polyvinyl alcohol. The concentration of the aqueous solution is preferably 8 to 15% by weight.

In another embodiment, the raw material of the first step contains polyvinyl alcohol, regenerated polylactic acid, polybutylene succinate, freeze-dried cocoon shell powder and beeswax. Preferably, based on 100 parts by weight of polyvinyl alcohol (PVA), 90 to 125 parts by weight of regenerated polylactic acid (PLA), 10 to 30 parts by weight of polybutylene succinate (PBS), 15 to 30 parts by weight of freeze-dried cocoon shell powder It may be a mixture of 5 to 25 parts by weight of beeswax. The raw material is also characterized in that the total content in the solvent is 8 to 15% by weight.

Most preferably, the raw material is based on 100 parts by weight of polyvinyl alcohol (PVA), 125 parts by weight of recycled polylactic acid (PLA), 20 parts by weight of polybutylene succinate (PBS), 15 parts by weight of freeze-dried cocoon shell powder and 5 parts by weight of beeswax may be mixed. If it is out of the range that each of these raw materials is included, the strength of the felt as desired in the present invention, the dust-proof function, etc. may be deteriorated.

The raw material may be dissolved in an organic solvent such as ethanol, methanol, butanol, propylene glycol, or DMF (dimethyl formamide) by a conventional method. DMF may be used as the most suitable solvent. In addition, in a state dissolved in a solvent, it is preferable that the total content of all raw materials is 8 to 15% by weight, and it is preferable that the solvent is volatilized together with electrospinning. In the present invention, the electrospinning state is the best when the total content of the raw material is 10% by weight.

The electrospinning of the second step may be performed at a flow rate of 0.1 to 0.3 ml/h, a collector distance of 9 to 11 cm, a voltage of 4 to 6 kV, and a spinning time of 30 to 120 minutes. More preferably, electrospinning may be performed at a flow rate of 0.2 ml/h, a collector distance of 10 cm, a voltage of 5 kV, and a spinning time of 30 minutes.

The freeze-dried cocoon shell powder used in the present invention may be obtained by freeze-drying and powdering raw silk yarn, which is difficult to extract silk, as the pupae tear the cocoon. The freeze-dried cocoon shell powder has the effect of improving the electrostatic force of the felt for the mask, and improving the friction caused by the skin contact of the felt to reduce skin flushing or allergic reactions.

The recycled polylactic acid (PLA) used in the present invention may be a biodegradable plastic bag material that is used and discarded. Preferably, it may be a plastic bag made of a PLA material derived from corn starch having a weight average molecular weight (MW) of 100,000 to 300,000 g/mol. The polyvinyl alcohol used in the present invention may have a weight average molecular weight of 25,000 to 300,000 g/mol.

The present invention relates to a method for manufacturing a biodegradable mask using polyvinyl alcohol, wherein the polyvinyl alcohol is easy to manufacture non-woven fabric and is easily decomposed through enzymatic decomposition, thereby having excellent environmental protection effect.

1 and 2 are optical micrographs of PMMA spinning felt.
3 is an optical micrograph of PVA spinning felt.
4 is an electron microscope analysis photograph of PVA spinning felt.
5 is an electron microscope analysis photograph of a dental mask, a Kf 94 mask, PVA felt, and flour particles.
6 is a photograph showing the biodegradability test result procedure of the mask.
7 is a photograph showing the biodegradation result of the mask.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, it is provided to fully convey the spirit of the present invention to those skilled in the art so that this disclosure will be thorough and complete.

<Example 1. Confirmation of use of recycled PLA (Poly Lactic Acid) mask material>

After use, 3.5 g of PLA (Poly Lactic Acid) vinyl to be discarded was cut into small pieces and dissolved in 46.5 g of DMF (dimethyl formamide) to prepare a total of 50 g, heated to 40 ° C for more than 12 hours and stirred at 300 rpm, but did not dissolve. Therefore, it was confirmed that it is not easy to apply the mask material in this state. It also did not dissolve well even when the temperature was increased significantly (it is generally known that re-solution of reused PLA is difficult).

<Example 2. Manufacture of filter using polymethyl methacrylate (PMMA) for setting mask material manufacturing conditions>

This is an experiment that manipulates biodegradable materials so that they become the most suitable conditions for electrospinning. Although PMMA belongs to non-biodegradable plastics, not biodegradable plastics, it is a material that can more easily identify manipulation variables, so experiments were conducted using it. Set the device by varying the concentration, flow rate, distance, voltage, time, etc. for each radiation, and conduct electrospinning for a total of 30 minutes. By comparing several radiated filters, the optimal conditions for filter manufacturing are derived. The concentration and solvent of PMMA were the same as that of PLA (solvent: DMF, concentration of 7% by weight, heating to 40° C. for 12 hours or more and stirring at 300 rpm to completely dissolve).

Electrospinning device, PMMA (polymethyl methacrylate solution), syringe, aluminum foil (collector), and tips of 18G and 23G were prepared as experimental preparations, and PMMA electrospinning conditions were as follows.

Flow rate: unified at 0.5ml/h

Distance: unified to 10 cm (collector shape is the same)

Voltage: unified to 5kV

Spinning time: Filter 1 is 18G for 5min, Filter 2 is 18G 2min 30sec, then 23G 2min 30sec is running, Filter 3 is 23G for 5min.

For electrospinning, an electrospinning device was installed and grounded to a metal collector, PMMA was put in a syringe, and felt was left on the collector for 30 minutes, and after making felt 1, 2, 3, it was observed with an optical microscope (OM). Thus, it is shown in FIG. 1 .

On the other hand, in all subsequent experiments along with this experiment, the overall state of the felt (the presence or absence of beads, agglomeration, etc.) was checked with an optical microscope, and the emission characteristics of the specific filter were confirmed by electron microscopy (FE-SEM) imaging.

As a result of the measurement, under these conditions, the felt was spun too thinly and it was difficult to remove it. To explain this in detail, as the voltage decreased, the fiber diameter increased, and as the voltage increased, the surface charge increased. The higher the voltage, the larger the spraying angle, and the fibers could not be gathered in one place, making it difficult to spin in the form of felt. In addition, as the flow rate increased, the fiber diameter decreased. This is because, if the solvent is not volatilized, agglomeration occurs, and the solvent volatilizes to increase the repulsive force, and then the diameter decreases as the jet becomes thinner.

It is confirmed that the distance from the syringe to the collector should be appropriate, and if the distance is too short, the fibers containing the solvent reach it, so friction occurs during the drying process, and it is confirmed that it becomes difficult to strengthen the binding force of the fibers.

On the other hand, additionally, experiments were also conducted with different concentrations of PMMA. As the concentration of PMMA increased, the fiber diameter increased, and if the concentration was too low, the viscosity decreased. . In addition, when the concentration was too high, the electrical repulsive force did not overcome the viscosity, so radiation was not performed. And, the higher the viscosity of the solution due to the difference in concentration, the thinner the fibers could be drawn. As such, it was confirmed that as the viscosity and total charge density of the polymer solution were higher, fibers without beads were produced, and thus thinner fibers could be obtained. In this experiment, it can be seen that the concentration of PMMA is appropriate when the solution is 5-7% by weight.

In addition, through the results of these first experiments, it was found that the radiation time control and flow rate control were necessary, and it was decided to re-explore the optimal experimental conditions. Also, since there was almost no difference in diameter in 18G, 18G+23G, and 23G, it was decided to unify and radiate to 23G without distinction.

Accordingly, the second experiment was performed as follows, and the optical microscope measurement results are shown in FIG. 2 . The concentration of PMMA was the same as 7% by weight.

Flow rate: unified at 0.5ml/h

Distance: unified to 10 cm (collector shape is the same)

Voltage: unified to 5.4kV

Spinning time: Filter 1 is 18G for 30min, Filter 2 is 18G 15min and then 23G 15min, Filter 3 is 23G for 30min.

In other words, since the result of the filter production was irradiated to the extent that it was scratched, in the second experiment, the spinning time was increased and the flow rate was adjusted in order to proceed with the filtering test. By increasing the time from 5 minutes to 30 minutes, all filters were made thick enough to fall off the aluminum foil, and the conditions were modified from 18G to 23G. Accordingly, a total of three types of felt were produced. Thus, unlike the previous experiment, the filtering ability test was performed by peeling the felt.

To explain the experimental results, as can be seen from the optical microscope analysis picture of FIG. 2 , electrospinning was performed evenly throughout. Beads (beads) did not appear, and it can be seen that the thickness of each spun solution is also constant.

<Example 3. PVA (polyvinyl alcohol) filter manufacturing>

Another biodegradable plastic, PVA, was spun under the conditions obtained by spinning PMMA to fabricate a filter. For this, prepare an electrospinning device, PVA aqueous solution (10% by weight), syringe, aluminum foil (collector), 18G tip, PVA spinning condition, flow rate: 0.2ml/h, uniform distance: 10cm (collector) Same shape), voltage: different for each experimental condition, but radiating time: 10 minutes were applied equally to all. An optical micrograph of the radiation result is shown in FIG. 3 .

As PVA is a water-based polymer, water as a solvent does not volatilize well, so agglomeration occurs during electrospinning, making it difficult to spin into felt. Therefore, several modifications were made to find the appropriate concentration of the PVA solution, but the experiment was successfully performed by irradiating it at a significantly higher concentration than that of PMMA. The appropriate experimental concentration was 8 to 15% by weight, and spinning was best at 10% by weight.

As can be seen from the optical micrograph of FIG. 3 and the electron micrograph of FIG. 4, even with 8 to 15 wt% PVA, it was possible to radiate without a significant difference from the 5 to 7 wt% PMMA filter, and the radiation was not cut off and each interval and thickness The back was constantly radiated.

<Example 5. Comparison of electron micrograph measurements of each mask material>

As shown in FIG. 5, electron micrographs were compared for a dental mask, a Kf 94 mask, and a PVA felt. As a result, it was confirmed that PVA felt has a structure that can be usefully used for filtering fine dust or viruses like a dental mask or KF94 mask material.

In addition, the flour to be used in place of fine dust in the present invention was also photographed at the same magnification, and it was found that flour is a material that can replace fine dust.

<Example 6. Confirmation of filtration ability>

The droplet blocking performance of a commercially available mask and a mask manufactured using a biodegradable material was compared. In addition, as a material to replace the dust component, the filtration ability of each filter was confirmed by measuring the mass of each sheet after the flour was passed through.

For the experiment, vacuum filtration set (filter), Filtration membrane (filter paper), Shieve (sieve, 126 μm), Mortar (mortar), dental mask, KF94 mask, and flour were prepared.

The filtration ability was checked through the following steps.

① Measure 0.1g of wheat flour (expected to be about 10μm).

② Cut the electrospun filter according to the size of the filter by 30min, 60min, 120min together with the commercially available filter.

③ Measure the weight of the mask and inlay with a scale.

④ Prepare a filtration membrane (0.45 μm) so that the flour particles that have passed through the commercially available mask do not enter the filter.

⑤ After tightening the filter, turn on the vacuum pump and drop the flour from above. If there is lumped flour, blow it with a blower (handy pump) to spread it evenly.

⑥ Remove the beaker from the filter and measure the weight of the mask filter and flour. (At this time, the mass of the inlay is also measured separately.)

The measured values are shown in Table 1 below.

KF 94 dental 30min PVA 60min PVA 120min PVA Before (Membrane) 0.086g 0.086g 0.086g 0.086g 0.086g After (Membrane+Flour) 0.086g 0.086g 0.087g 0.087g 0.087g flour weight 0.000g 0.000g 0.001g 0.001g 0.001g Flour Filtration Prevention Rate 100% 100% 99% 99% 99%

As a result of the experiment, as shown in Table 1, the KF94 mask and the tental mask showed a filtration rate of 100% with an increased weight of 0.000 g. In g, a filtration rate of 99% was recorded.

<Example 7. Confirmation of biodegradation ability>

The biodegradability of the prepared PVA biodegradable filter was evaluated. Since natural biodegradation requires a long time, the biodegradation period was shortened by using the lipase enzyme at an appropriate temperature. In addition, since it is difficult to measure the change in weight due to soil, the degree of biodegradation was checked and compared with the naked eye and photograph. For this, 500 g of dry masato, 0.1 g of lipase enzyme, a dental mask, a KF94 mask, a PVA filter spun for 30 minutes, 500 ml of water, and a temperature maintaining device were prepared and the next step was performed.

① Add the enzyme to the dried massato and mix evenly.

② Bury the dental dust off the flour, the KF94 mask, and the PVA filter to a depth of 2cm.

③ After spraying 500ml of water evenly, do not close the lid completely to allow air to pass through.

④ Keep the container filled with soil at 50°C and observe the change.

The experimental process is shown in FIG. 6, and the experimental results are shown in FIG.

In FIG. 7 , the left side is a PVA filter that completely disappeared after one hour after covering the soil, and the right side is a biodegradability test result of a commercially available mask with no change.

Accordingly, the biodegradation ability of the PVA filter manufactured in the present invention was verified, and the effect of reducing environmental pollution can also be verified.

<Example 8. Analysis>

As a result of observation with an optical microscope, the PVA solution is the most uniform filter among biodegradable plastics such as PVA and PLA, in which electrospinning is well done and beads are not observed. The mask filter can be manufactured most effectively when the PVA solution is set with a flow rate of 0.2ml/h, a distance from the collector of 10cm, a voltage of 5kV, and a radiation time of 30 minutes.

Unlike commercially available masks that have to be incinerated, masks made of such PVA felt are biodegradable within an hour if they are buried in the ground using enzymes when disposing of a biodegradable mask that has undergone an easy manufacturing process. Due to this, the biodegradable mask can be processed effectively and quickly when processing a large amount of mask.

On the other hand, since PVA is water-soluble, it is strong in water and requires additional experiments in consideration that the material of the filter must be a biodegradable material, so the following experiment was performed.

<Production Example 1. Manufacturing of new mask material>

The following materials were prepared by spinning. The target material is based on 100 g of PVA. After mixing 125 g of recycled PLA (waste plastic bag), 20 g of polybutylene succinate (PBS), 15 g of freeze-dried cocoon shell powder, and 5 g of beeswax, dissolve it in DMF to make 10% by weight. It was completely dissolved by heating to 40° C. for more than 12 hours and stirring at 300 rpm.

Thereafter, the felt was prepared by spinning in the same manner as the PVA sheet manufacturing conditions. After that, a flour test was conducted, and this felt material confirmed that the dust-proofing effect of flour was similar to that of a dental mask.

<Preparation Examples 2 to 4. Preparation of new mask material prepared by varying the raw material content ratio>

A felt was prepared in the same manner as in Preparation Example 1, but the content of each raw material component was adjusted as shown in Table 2 below to prepare a felt for a mask.

PVA
(g) Recycled PLA
(g) PBS
(g) Freeze-dried cocoon
husk powder (g) wax
(g) gross weight
(g) Preparation Example 1 100 125 20 15 5 265 Preparation 2 100 125 10 25 5 265 Preparation 3 100 100 25 30 10 265 Preparation 4 100 90 30 20 25 265

<Example 9. Performance evaluation of mask material i>

For the felt materials of Preparation Examples 1 to 4, dust-proof ability was observed using wheat flour. As a result, it was confirmed that the result was similar to the dental mask as shown in Table 3 below.

Performance evaluation of mask material dustproof Felt of Preparation Example 1 Similar to a dental mask Felt of Preparation Example 2 Similar to a dental mask Felt of Preparation Example 3 Similar to a dental mask Felt of Preparation Example 4 Similar to a dental mask

< Example 10. Performance evaluation of mask material ii>

It was confirmed whether the felt material of Preparation Examples 1 to 4 could function well as a mask. In particular, contact allergy, contact dermatitis, rhinitis, etc. became problems due to skin friction due to wearing a mask every day, and skin friction and touch were checked. For this purpose, 10 high school students were asked to evaluate each mask felt material using a 5-point scoring method (1 point: very bad - 5 points: very good), and this is shown in Table 4. Moisture resistance was checked by checking the strength felt when each wet felt was torn by hand.

Performance evaluation of mask material moisture resistance skin friction relief soft to the touch PMMA Felt 4.9 2.3 2.8 PVA felt 3.1 3.4 3.2 Felt of Preparation Example 1 4.6 4.2 4.2 Felt of Preparation Example 2 4.4 4.0 3.9 Felt of Preparation Example 3 4.3 4.2 4.1 Felt of Preparation Example 4 4.5 4.3 4.4

From the results in Table 4, it can be confirmed that the felts of Preparation Examples 1 to 4 are more excellent in moisture resistance, skin friction relief, soft touch, and the like, compared to PVA felt.

Claims (4)

(Step 1) 100 parts by weight of polyvinyl alcohol, 90 to 125 parts by weight of regenerated polylactic acid, 10 to 30 parts by weight of polybutylene succinate, 15 to 30 parts by weight of freeze-dried cocoon shell powder, and 5 to 25 parts by weight of beeswax Preparing a raw material in which the included composition is contained in a total content of 8 to 15% by weight in a solvent; and,
(Second step) producing a felt by electrospinning the raw material at a flow rate of 0.1 to 0.3 ml/h, a collector distance of 9 to 11 cm, a voltage of 4 to 6 kV, and a spinning time of 30 to 120 minutes;
A method of manufacturing a biodegradable mask using polyvinyl alcohol, comprising: delete delete A biodegradable mask manufactured by the method of claim 1 .

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