CN109381736B

CN109381736B - A biodegradable medical dressing

Info

Publication number: CN109381736B
Application number: CN201811140792.7A
Authority: CN
Inventors: 郭筱洁
Original assignee: Hangzhou Dianzi University
Current assignee: Zhejiang Jieda New Material Technology Co ltd
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2021-06-15
Anticipated expiration: 2038-09-28
Also published as: CN109381736A

Abstract

The application discloses biodegradable medical dressing, including following raw materials components: catkin, viscose and chitosan. The biodegradable medical dressing provided by the invention recycles catkin, is used for producing non-woven medical dressings, changes waste into valuable, and has biodegradability, high water absorption, antibacterial function and hemostatic function.

Description

Biodegradable medical dressing

Technical Field

The invention relates to the technical field of medical supplies, in particular to a biodegradable medical dressing.

Background

The catkin dancing in spring is a flying season in a flying manner and is also a season with various allergic symptoms, the caused allergy mainly occurs in the upper respiratory tract, after the catkin is sucked into the nasal cavity, the catkin can cause strong stimulation, watery nasal discharge, cough, asthma and other reactions, such as skin itch, conjunctiva redness and the like, and can seriously affect sleep, the catkin dancing in flying manner can also cause certain damage to the urban ecological environment, and the catkin can also cause harm to public safety, traffic safety and public facilities, for example, the catkin can block the sight of pedestrians and vehicles during traveling, so that the traffic safety is affected. However, according to medical history, catkin is a traditional Chinese medicine with cooling and bleeding stopping effects, has small toxic and side effects and no drug resistance, is used as a natural material, and has wide sources because the raw materials are presented by nature. However, the willow flock is short and loose, has a low strength value, is difficult to spin into yarn, and is generally directly treated as waste, so that great cellulose resource waste is caused.

Disclosure of Invention

Aiming at the problems, the invention provides the biodegradable medical dressing, which recycles catkin for producing the non-woven medical dressing, changes waste into valuable, and has biodegradability, high water absorbability, antibacterial function and hemostatic function.

The technical scheme adopted by the invention is as follows: the invention provides a biodegradable medical dressing, which comprises the following raw material components: catkin, viscose and chitosan.

In an embodiment of the present invention, the mass ratio of the catkin to the viscose is 15/85-40/60.

In one embodiment of the present invention, the catkin includes catkin fibers and catkin seeds.

In an embodiment of the present invention, the structure of the catkin fiber is a hollow structure.

In one embodiment of the present invention, the biodegradable medical dressing has a thickness of 0.1-10 mm.

In an embodiment of the present invention, the liquid absorption rate of the biodegradable medical dressing is 10% or more.

In one embodiment of the invention, the air permeability of the biodegradable medical dressing is more than 1500 mm/s.

In an embodiment of the present invention, the preparation method of the biodegradable medical dressing includes the following steps:

s1, cleaning catkin, removing impurities, and then drying in vacuum at 40-60 ℃;

s2, processing the catkin and the viscose into catkin/viscose non-woven fabric;

s3, preparing a chitosan finishing liquid with the mass fraction of 0.1-0.5 g/ml;

s4, performing secondary dipping and secondary rolling after-treatment on the catkin/viscose non-woven fabric by using the chitosan finishing liquid prepared in the step S3;

s5, drying the finished catkin/viscose non-woven fabric at 80-100 ℃ for 5-15 min.

In an embodiment of the present invention, the step S3 includes the following steps: adding chitosan into acetic acid solution, stirring at 60 ℃ until the chitosan is fully dissolved, then adopting a bath ratio of 1:30, adding the acetic acid solution into the fully dissolved chitosan solution for dilution, and preparing the chitosan finishing liquid with the mass fraction of 0.1-0.5 g/ml.

In an embodiment of the present invention, the second soaking and second rolling in step S4 includes the following steps: putting the catkin/viscose non-woven fabric into a chitosan finishing liquid, uniformly covering the finishing liquid on the non-woven fabric with stirring of an electric stirrer, soaking for 30min at 60 ℃, performing first rolling, then soaking a sample at 60 ℃ for 30min, and performing second rolling, wherein the rolling residue rate after the second soaking and the second rolling is 80-90%.

The invention has the beneficial effects that: the invention provides a biodegradable medical dressing, which is prepared by mixing catkin and viscose fiber to prepare catkin/viscose non-woven fabric, performing after-treatment by using a chitosan finishing liquid and finally drying. The waste catkin is used as a raw material for producing the biodegradable medical dressing, so that waste is changed into valuable; catkin is a natural material with sufficient source, and the non-woven fabric made of the catkin has biodegradability; the catkin has a high hollow structure, can absorb a large amount of water, and the non-woven fabric prepared from the catkin has high water absorption and a hemostatic function; the chitosan has an antibacterial effect, so that the catkin/viscose non-woven fabric is subjected to after-treatment by the chitosan finishing liquid, and the prepared biodegradable medical dressing has an antibacterial function.

Drawings

FIG. 1 is a graph showing the effect of the present invention on Staphylococcus aureus resistance of unfinished catkin/viscose nonwovens;

FIG. 2 is a graph showing the antibacterial effect of the post-finished catkin/viscose nonwoven fabric of the present invention on Staphylococcus aureus;

FIG. 3 is a graph showing the effect of the nonwoven fabric of catkin/viscose of the present invention on the antibacterial effect of Escherichia coli;

FIG. 4 is a graph showing the effect of the post-treated catkin/viscose nonwoven fabric of the present invention on the antibacterial test of Escherichia coli.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown.

The invention provides a biodegradable medical dressing, which comprises the following raw material components: catkin, viscose and chitosan. The catkin fiber is thin and short, and is difficult to be singly formed into a net or the fiber net is thin, and the strength of the prepared composite material is low, so that the catkin and the viscose fiber are mixed to prepare the medical dressing. Catkin is easy to cause allergic symptoms, has certain damage to the environment, is often treated as waste, and is used as a raw material for producing the biodegradable medical dressing, so that waste is changed into valuable; catkin is a traditional Chinese medicine with cooling and hemostatic effects, has small toxic and side effects, is used as a natural material, has sufficient sources, and is biodegradable; the catkin has a high hollow structure, can absorb a large amount of water, and the non-woven fabric made of the catkin has high water absorption; the chitosan has an antibacterial effect, so that the catkin/viscose non-woven fabric is subjected to after-treatment by the chitosan finishing liquid, and the prepared biodegradable medical dressing has an antibacterial function.

The catkin comprises catkin fiber and catkin seeds, the main component of the catkin fiber is cellulose, the length of the catkin fiber is 2-3mm, the average diameter is 6.5-13.0 μm, the catkin fiber is the same as common plant fiber, and the main component is cellulose. The hollow structure of the catkin fiber is beneficial to absorbing a large amount of water, and the hemostatic effect can be achieved in a short time. The catkin contains a lot of small catkin seeds, is dark green and granular, has a length of 1.2mm-1.5mm, a tip at one end and a big end at the other end, and is wrapped with a large amount of fine fiber velvet. The catkin seed contains C and O as main components, as well as Ca, K, S, etc. in the amount of 0.79 wt% and 0.465 wt%, and has the functions of promoting blood coagulation, reducing the excitability of muscle and nerve, regulating several factors to stop bleeding, and eliminating local damage inflammation. The density value of catkin fiber and seed mixture thereof is 0.78-0.81g/cm³The density value is less than 1g/cm³Therefore, the catkin and the seeds thereof are easy to float in the air along with wind.

The invention also provides a preparation method of the biodegradable medical dressing, which is used for preparing the biodegradable medical dressing and comprises the following steps:

s2, mixing catkin and viscose fiber uniformly and processing the mixture into catkin/viscose non-woven fabric;

During the process of collecting catkin, impurities such as dust, leaves and the like are inevitably generated, and when the medical auxiliary material is prepared, the catkin is required to be cleaned in water for sanitation and aesthetic property, the impurities are removed, and then the catkin is dried in vacuum at 40-60 ℃. The loose catkin and viscose are processed into a dense catkin/viscose nonwoven. In the post-finishing process of the chitosan finishing liquid, the surface of the viscose/catkin non-woven material is uniformly coated with a layer of chitosan, and the chitosan has good film-forming property, so that the mechanical property of the finished non-woven fabric is optimized. The chitosan also has an antibacterial effect, so that the catkin/viscose non-woven fabric is subjected to after-treatment by the chitosan finishing liquid, and the prepared biodegradable medical dressing has an antibacterial function.

The step S2 includes a forming process and a needling process, the forming process includes an opener, a cotton feeder, a carding machine and a lapping machine arranged in sequence from a processing direction, the needling process includes a feeder, a pre-needling machine, a pre-rolling machine, a reverse needling machine and a main needling machine arranged in sequence from the processing direction, the opener is used for loosening and uniformly mixing catkin and viscose, the cotton feeder is used for opening and mixing fibers to form a regenerated fiber layer which is uniform from a weft direction, the carding machine is used for carding the regenerated fiber layer to form a single-layer fiber thin web, the lapping machine is used for cross-folding the single-layer fiber thin web processed by the carding machine to form a multi-layer fiber web, the feeder is used for feeding the multi-layer fiber web into the pre-needling machine, the pre-needling machine is used for needling and reinforcing the fluffy fiber web, the pre-rolling machine is used for rolling the fiber web, the reverse needling machine is used for reverse needling and reinforcing the multi-layer fiber web, the main needling machine is used for repeatedly needling and fixing the multiple layers of fiber webs to form the compact catkin/viscose non-woven fabric.

Preferably, the parameters of the needling process include: the feeding and discharging speed is 20m/min, the needling frequency is 33 times/min, the needling times of the main needling machine are 2 times, and the thickness, the gram weight, the mechanical property and the like of the prepared catkin/viscose non-woven fabric are optimal. The speed difference between the feeding and the discharging leads the fiber web to be stretched by drafting, the discharging speed is too low, the production efficiency is low, the discharging speed is too high, and the mechanical property and the dough density of the fiber web are reduced; the pressure given by the needling causes the fiber web to generate diffusion deformation, the needling times are too few, the fibers are not tightly entangled in an intercrossing way, the needling times are too many, the damage to part of the fibers in the fiber web can be caused, and the mechanical property and the surface density of the fiber web are reduced; too low needling frequency, not compact intercrossing and entanglement among fibers, too high needling frequency can also cause damage to part of fibers in the fiber web, and the mechanical property and the surface density of the fiber web are reduced.

The above step S3 includes the following steps: adding chitosan into acetic acid solution, stirring at 60 ℃ until the chitosan is fully dissolved, then adopting a bath ratio of 1:30, adding the acetic acid solution into the fully dissolved chitosan solution for dilution, and preparing the chitosan finishing liquid with the mass fraction of 0.1-0.5 g/ml.

The second dipping and second rolling in the step S4 includes the following steps: putting the catkin/viscose non-woven fabric into the chitosan finishing liquid, uniformly covering the finishing liquid on the non-woven fabric with stirring of an electric stirrer, soaking for 30min at the temperature of 60 ℃, performing first rolling, then soaking the sample at the temperature of 60 ℃ for 30min, and performing second rolling. The post-finishing is a processing process for improving the hand feeling and appearance of the fabric (such as stiffening finishing, soft finishing, calendering or napping and the like), improving the quality of the fabric and endowing the fabric with new functions (such as crease resistance, water resistance, stain resistance, corrosion resistance, mildew resistance, moth resistance, bacteria resistance and the like) through a physical, chemical or physical and chemical method. The catkin/viscose non-woven fabric has no antibacterial effect, and after the post-finishing by the chitosan finishing liquid, an antibacterial ring appears, so that the catkin/viscose non-woven fabric after the post-finishing has a good antibacterial effect.

The rolling residual rate after the two-dipping and the two-rolling is 80 to 90 percent. The percent reduction, also known as the wet pick, is the weight of the liquid carried on the fabric as a percentage of the fabric's own weight. The accurate expression is that the weight of the solution on the cloth cover after the solution is fed through the size box and rolled by the rolling rod is the percentage of the original weight of the fabric before padding. The calculation formula of the rolling residual ratio is as follows: the percent after rolling is ═ weight of the cloth after double-impregnation and double-rolling-weight of the dry cloth before the experiment)/weight of the dry cloth before the experiment ] × 100%.

The catkin/viscose non-woven fabric is subjected to two-time soaking and two-time rolling, and then is dried in a drying oven at the temperature of 80-100 ℃ for 5-15min, and the proper drying temperature can ensure the drying speed of the finished fabric, so that a film formed by chitosan is fixed on the surface of the fabric, the fabric is prevented from yellowing, the thermal decomposition of fibers caused by overhigh temperature can also be avoided, and the strength of the fabric is reduced.

The viscose fiber is prepared by using natural materials (wood, cotton linter, bagasse and the like) as raw materials through wet spinning. The viscose fiber has good moisture absorption, the moisture regain is about 13 percent, the breaking strength is 1.6-2.7cn/dtex, the elongation at break is 16-22 percent, and the density of the viscose fiber is 1.50-1.52g/cm close to that of cotton³. The hygroscopicity of the viscose fiber meets the physiological requirements of human skin, and the viscose fiber has the characteristics of smoothness, coolness, air permeability, static resistance, ultraviolet resistance, good dyeing fastness and the like, and particularly has uniform length and fineness of the viscose fiber, low impurity content in the fiber and good quality of the prepared composite material. The raw material of the viscose is from natural materials, and the catkin fiber and the seeds thereof are also natural materials, so that the non-woven material prepared by mixing the catkin and the viscose has biodegradability.

The mass ratio of the catkin to the viscose is 15/85-40/60, when the content of the catkin is lower than 15%, the medical performance of the catkin cannot be well reflected, and when the content of the catkin exceeds 40%, the mechanical performance of the biodegradable medical dressing is not ideal enough, so that the mass ratio of the catkin to the viscose is 15/85-40/60, and various performances of the catkin/viscose non-woven medical dressing are relatively better. The thickness of the biodegradable medical dressing can be made to be 0.1-10mm, and the biodegradable medical dressing can be processed and manufactured according to the requirement.

Example one

A biodegradable medical dressing is prepared from catkin and viscose at 5/95 weight ratio. The catkin and the viscose are processed into catkin/viscose non-woven fabrics.

Example two

A biodegradable medical dressing is prepared from catkin and viscose at 5/95 weight ratio. Processing catkin and viscose into catkin/viscose non-woven fabric, performing secondary soaking and secondary rolling after finishing the catkin/viscose non-woven fabric by using chitosan finishing liquid, and finally drying the finished viscose non-woven fabric for 5-15min at 80-100 ℃.

EXAMPLE III

A biodegradable medical dressing is prepared from catkin and viscose at 15/85 weight ratio. The catkin and the viscose are processed into catkin/viscose non-woven fabrics.

Example four

A biodegradable medical dressing is prepared from catkin and viscose at 15/85 weight ratio. Processing catkin and viscose into catkin/viscose non-woven fabric, performing secondary soaking and secondary rolling after finishing the catkin/viscose non-woven fabric by using chitosan finishing liquid, and finally drying the finished viscose non-woven fabric for 5-15min at 80-100 ℃.

EXAMPLE five

A biodegradable medical dressing is prepared from catkin and viscose at 25/75 weight ratio. The catkin and the viscose are processed into catkin/viscose non-woven fabrics.

EXAMPLE six

A biodegradable medical dressing is prepared from catkin and viscose at 25/75 weight ratio. Processing catkin and viscose into catkin/viscose non-woven fabric, performing secondary soaking and secondary rolling after finishing the catkin/viscose non-woven fabric by using chitosan finishing liquid, and finally drying the finished viscose non-woven fabric for 5-15min at 80-100 ℃.

EXAMPLE seven

A biodegradable medical dressing is prepared from catkin and viscose at 35/65 weight ratio. The catkin and the viscose are processed into catkin/viscose non-woven fabrics.

Example eight

A biodegradable medical dressing is prepared from catkin and viscose at 35/65 weight ratio. Processing catkin and viscose into catkin/viscose non-woven fabric, performing secondary soaking and secondary rolling after finishing the catkin/viscose non-woven fabric by using chitosan finishing liquid, and finally drying the finished viscose non-woven fabric for 5-15min at 80-100 ℃.

Example nine

A biodegradable medical dressing is prepared from catkin and viscose at 40/60 weight ratio. The catkin and the viscose are processed into catkin/viscose non-woven fabrics.

Example ten

A biodegradable medical dressing is prepared from catkin and viscose at 40/60 weight ratio. Processing catkin and viscose into catkin/viscose non-woven fabric, performing secondary soaking and secondary rolling after finishing the catkin/viscose non-woven fabric by using chitosan finishing liquid, and finally drying the finished viscose non-woven fabric for 5-15min at 80-100 ℃.

EXAMPLE eleven

A biodegradable medical dressing is prepared from catkin and viscose at 45/55 weight ratio. The catkin and the viscose are processed into catkin/viscose non-woven fabrics.

Example twelve

A biodegradable medical dressing is prepared from catkin and viscose at 45/55 weight ratio. Processing catkin and viscose into catkin/viscose non-woven fabric, performing secondary soaking and secondary rolling after finishing the catkin/viscose non-woven fabric by using chitosan finishing liquid, and finally drying the finished viscose non-woven fabric for 5-15min at 80-100 ℃.

The processing steps for the nonwovens of examples 1-12 above are as follows:

(1) uniformly loosening the catkin and the viscose by using an opener;

(2) preparing the uniformly loosened catkin and viscose into regenerated fibers with uniform warp and weft directions by using a cotton feeder;

(3) carding the regenerated fiber layer by a carding machine to form a single-layer fiber thin net;

(4) using a lapping machine to fold the single-layer fiber thin net in a cross way to form a multi-layer fiber net;

(5) feeding the multilayer fiber web into a pre-needling machine by using a feeding machine, wherein the feeding and discharging speed is 20.00 m/min;

(6) needling and reinforcing the fluffy multi-layer fiber web by using a pre-needling machine, wherein the feeding and discharging speed is 20.00m/min, and the needling frequency is 33 times/min;

(7) a pre-rolling machine is used for rolling and pressing the multilayer fiber web;

(8) reinforcing the multilayer fiber web by reverse needling with a reverse needling machine, wherein the feeding and discharging speed is 20.00m/min, and the needling frequency is 33 times/min;

(9) and (3) repeatedly needling and fixing the multi-layer fiber web by using a main needling machine to form the compact catkin/viscose non-woven fabric, wherein the processing frequency of the main needling machine is two times, the feeding and discharging speed is 20.00m/min, and the needling frequency is 33 times/min.

The processing steps of the two-dipping two-rolling of the above examples 2, 4, 6, 8, 10 and 12 are as follows:

(1) putting catkin/viscose non-woven fabric or viscose non-woven fabric into chitosan finishing liquid with the mass fraction of 0.1-0.5g/ml, uniformly covering the finishing liquid on the non-woven fabric with the stirring of an electric stirrer, soaking for 30min at the temperature of 60 ℃, and then carrying out first rolling;

(2) and then putting the catkin/viscose non-woven fabric or the viscose non-woven fabric after the first rolling into a chitosan finishing liquid with the mass fraction of 0.1-0.5g/ml, uniformly covering the finishing liquid on the non-woven fabric with the stirring of an electric stirrer, soaking for 30min at the temperature of 60 ℃, and then carrying out second rolling.

Table 1 catkin/viscose nonwoven fabric performance testing

According to the test results in table 1, it can be seen that: the surface density is gradually reduced along with the increase of the catkin content, the longitudinal breaking strength and the transverse breaking strength of the catkin/viscose non-woven fabric are reduced, and when the catkin content exceeds 40%, the breaking strength and the bursting strength of the catkin/viscose non-woven fabric are sharply reduced. The mechanical property and the surface density of the non-woven fabric after the second soaking and the second rolling of the chitosan are optimized to a certain extent, and the breaking strength and the bursting strength of the non-woven fabric are improved. Therefore, the content of catkin is not more than 40% in terms of the longitudinal breaking strength, the transverse breaking strength and the area density.

When the catkin content is less than 15%, the air permeability of the non-woven fabric is remarkably reduced along with the increase of the catkin content, and the air permeability reduction rate is relatively gentle after the catkin content exceeds 15%. The liquid absorption rate of the non-woven fabric is increased along with the gradual increase of the content of the catkin, and when the weight ratio of the catkin reaches 15%, the liquid absorption rate of the non-woven fabric is obviously increased, so that the hemostatic effect is achieved. In view of air permeability and liquid absorption rate, the content of catkin is not lower than 15%, and the medical property of catkin can be better reflected. Therefore, the ratio of the catkin to the viscose is 15/85-40/60, and the catkin/viscose non-woven medical dressing has relatively better various performances.

The catkin/viscose non-woven fabric processed by using the catkin/viscose according to the ratio of 20/80 is selected to carry out an antibacterial property test experiment on staphylococcus aureus and escherichia coli, wherein the staphylococcus aureus represents gram-positive bacteria, the escherichia coli represents gram-negative bacteria, and the specific experiment steps are as follows: preparing agar, placing in a culture dish, cooling, solidifying, streaking bacteria on nutrient agar plate, and culturing in a 37 deg.C gas bath constant temperature oscillator for one day to activate bacteria; preparing a nutrient broth the next day, taking a typical colony from the activated bacteria, inoculating the colony in the nutrient broth, and culturing the colony in a gas bath constant temperature oscillator at 37 ℃ and 130r/min for one day to obtain a bacterial suspension; preparing agar to prepare a nutrient agar plate on the third day, sucking 0.1mL of the nutrient agar plate from the bacterial suspension by using a liquid transfer gun, placing the nutrient agar plate in the plate, uniformly coating the nutrient agar plate by using a coating rod, and cutting catkin/viscose non-woven fabric samples into circles with the same size before and after finishing into the center when the bacterial suspension is slightly dried in the plate; the experimental phenomenon was observed on the fourth day. Referring to fig. 1-4, the unfinished catkin/viscose nonwoven fabric has no antibacterial property, i.e. the viscose and the catkin itself have no antibacterial effect, and the finished catkin/viscose nonwoven fabric can generate antibacterial rings, so the finished catkin/viscose nonwoven fabric has good antibacterial effect.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings can be directly or indirectly applied to other related technical fields and are included in the scope of the present invention.

Claims

1. a biodegradable medical dressing, is characterized in that, comprises following raw material components: catkins, viscose fiber and chitosan;

The catkins and the viscose fibers are made into catkin/viscose non-woven fabrics, and the post-finishing is carried out by two dips and two rollings through a chitosan finishing solution;

Wherein, the catkins include catkin fibers and catkin seeds, and the mass ratio of the catkins and the viscose fibers is 15/85-40/60;

The chitosan finishing solution is prepared by adding chitosan into an acetic acid solution and stirring until fully dissolved, and then diluting the fully dissolved chitosan solution with an acetic acid solution.

2 . The biodegradable medical dressing according to claim 1 , wherein the structure of the catkin fibers is a hollow structure. 3 .

3. The biodegradable medical dressing according to claim 1, wherein the thickness of the biodegradable medical dressing is 0.1-10 mm.

4 . The biodegradable medical dressing according to claim 1 , wherein the liquid absorption rate of the biodegradable medical dressing is more than 10%. 5 .

5 . The biodegradable medical dressing according to claim 1 , wherein the air permeability of the biodegradable medical dressing is more than 1500 mm/s. 6 .

6. The biodegradable medical dressing according to claim 1, wherein the preparation method of the biodegradable medical dressing comprises the following steps:

S1: cleaning catkins, removing impurities, and then vacuum drying at 40-60 °C;

S2: process catkin and viscose fiber into catkin/viscose non-woven fabric;

S3: prepare a chitosan finishing solution with a mass fraction of 0.1-0.5 g/ml;

S4: utilize the chitosan finishing liquid configured in step S3 to carry out the finishing of two dips and two rollings to catkins/viscose nonwovens;

S5: Bake the finished catkin/viscose non-woven fabric at 80-100° C. for 5-15 minutes.

7 . The biodegradable medical dressing according to claim 6 , wherein the step S3 comprises the following steps: adding chitosan into the acetic acid solution, stirring at 60° C. until fully dissolved, and then using a 1:30 bath The fully dissolved chitosan solution is diluted with an acetic acid solution to prepare a chitosan finishing solution with a mass fraction of 0.1-0.5 g/ml.

8. The biodegradable medical dressing according to claim 6, wherein the second dipping and second rolling of the step S4 comprises the following steps: placing the catkin/viscose non-woven fabric in the chitosan finishing solution, accompanied by the following steps: With the stirring of the electric stirrer, the finishing liquid was evenly covered on the non-woven fabric, and after immersing at 60 °C for 30 minutes, the first pressing was performed, and then the sample was placed at 60 °C and immersed for 30 minutes. For the second rolling, the residual ratio after the second dipping and the second rolling is 80-90%.