KR20200115339A - Method for manufacturing hydrophilic kapok fiber and hydrophilic kapok fiber produced therby - Google Patents

Abstract

The present application provides a method of manufacturing a hydrophilic kapok fiber having excellent wettability and water absorption of a surface without damage and yellowing of the fiber, and a hydrophilic kapok fiber produced thereby.

Description

[Method for manufacturing hydrophilic kapok fiber and hydrophilic kapok fiber produced therby}

The present application relates to a method of manufacturing a hydrophilic kapok fiber and a hydrophilic kapok fiber produced thereby.

Biodegradable cellulose is used in various industrial fields due to its advantages such as renewable, eco-friendly, and low price. Among them, kapok fiber is an eco-friendly natural resource based on cellulose and is mainly grown in Southeast Asia, Malaysia, and Sri Lanka.

Kapok fiber is a yellowish brown fine fiber with a luster equivalent to the seeds of a kapok tree, and has a huge lumen giving a large and uniform porosity of up to 90%, which is characterized by ultra light weight and hydrophobicity compared to cotton fiber. have. It has excellent breathability, heat retention, and elastic resilience, and is used as bedding equipment such as pillows and cushions, oil absorbents, sound absorbing materials for transportation means such as ships, automobiles, and airplanes, and as fillers for life jackets with morphological safety. It is narrow. As described above, the kapok fiber is a cellulose fiber having a wax-like surface, but in order to apply it to a water-based papermaking process or fiber and clothing industry, a process of lowering hydrophobicity is essential.

On the other hand, the most commonly used method for lowering the hydrophobicity of kapok fibers is alkali treatment, and among them, a method using sodium hydroxide (NaOH) is typically known. Alkali treatment reduces crystalline cellulose and increases amorphous cellulose. Depending on the result of the alkali treatment the kapok fibers wax to impart smoothness and swelling removed, it is damaged and the physical deformation of the hollow of the surface is to occur, whereby the removal of acetyl groups and hydroxyl groups (OH ^-) that reveal improved absorbent It is known. However, sodium hydroxide has a problem of causing fiber damage and yellowing. In addition, there are oxidation, acid, and solvent treatments, but it is known that the water absorbency is inferior to that of alkali.

The present application provides a method of manufacturing a hydrophilic kapok fiber having excellent wettability and water absorption of a surface without damage and yellowing of the fiber, and a hydrophilic kapok fiber produced thereby.

The present application relates to a method of manufacturing a hydrophilic kapok fiber.

1 is a flowchart of a manufacturing method according to the present application.

Specifically, the method of manufacturing a hydrophilic kapok fiber according to the present application includes the step of preparing an untreated kapok fiber, and a first pretreatment aqueous solution comprising a pretreatment material for removing the untreated kapok fiber and a hydrophobic group of the kapok fiber And preparing a first mixed solution by mixing, and removing the hydrophobic group of the kapok fiber by heat treating the first mixed solution. In addition, preparing a second mixed solution by mixing the kapok fiber from which the hydrophobic group has been removed and a second pre-treatment aqueous solution containing a pre-treatment material that imparts a hydrophilic group to the kapok fiber, and reacting the second mixed solution at room temperature to give the kapok fiber a hydrophilic group. It includes the step of giving.

In the manufacturing method according to the present application, the hydrophobic group of the kapok fiber is removed using a first pre-treatment aqueous solution, and a hydrophilic group is provided to the kapok fiber using a second pre-treatment aqueous solution, thereby preventing damage and yellowing of the fiber, and Hydrophilic kapok fibers having excellent wettability and water absorption can be provided.

Specifically, the step of preparing the untreated kapok fiber is a step of preparing pure kapok fiber without physicochemical processing. For example, the untreated kapok fiber is 64% cellulose, 13% lignin, 8.6% water, 1.4-1.5% ash, 4.7-9.7% water-soluble material, 2.3-2.5% xylan, 0.8% It has the chemical composition of the wax. In addition, untreated kapok fibers exhibit high hydrophobicity due to about 13% acetyl groups contained in lignin, fats, oils, waxes, and the like. In addition, the untreated kapok fiber may be a short fiber having an average length of 18 to 27 nm, and a hollow ratio of 50 to 80%. The average length may be an average value obtained by repeatedly measuring the length of one strand three times after collecting 0.1 g of untreated K-phone fibers. And, the hollow ratio can be calculated as a percentage of the diameter of the hollow (s) / diameter of the fiber (S).

The step of preparing the first mixed solution is preceded by a process of preparing an untreated aqueous kapok fiber solution. The untreated aqueous kapok fiber solution is prepared by mixing the kapok fiber and water in a beaker so that the liquid ratio is 1:100. And, by stirring the prepared untreated kapok fiber aqueous solution and the first pre-treated aqueous solution for a predetermined period of time, a first mixed solution is prepared.

The step of removing the hydrophobic groups of the kapok fibers is a step of removing acetyl groups contained in lignin, fat, oil, wax, etc. of the kapok fibers by heat treatment of the first mixture. During the heat treatment, the pretreatment material of the first pretreatment aqueous solution may decompose the acetyl group of the kapok fiber. The kapok fiber from which the hydrophobic group is removed by the first pretreatment aqueous solution minimizes fiber damage and improves whiteness, thereby preventing a yellowing problem.

In addition, in the heat treatment process, the pretreatment material of the first pretreatment aqueous solution applies physical deformation to the surface and the hollow of the kapok fiber, and cracks and wrinkles are formed on the surface of the kapok fiber to which the physical deformation is applied, and the hollow is reduced. Cracks and wrinkles formed on the surface contribute to improving the wettability of the kapok fibers, and the reduced hollow contributes to improving the solubility of the kapok fibers.

In addition, the step of preparing the second mixed solution is preceded by a process of washing and drying the heat-treated first mixed solution with water to obtain a kapok fiber from which the hydrophobic group has been removed. The drying is performed, for example, in a desiccator preheated to 40° C. for 24 hours or more.

In the step of imparting a hydrophilic group to the kapok fiber, a hydrophilic group may be imparted to the kapok fiber by reacting the second mixed solution at room temperature for 24 hours or more, 36 hours or more, or 48 hours or more.

Thereafter, in the manufacturing method according to the present application, hydrophilic kapok fibers may be obtained by washing and drying the second mixed solution reacted at room temperature with water. Washing the second mixture with water is to remove the smooth touch imparted by the gelatin. The drying is carried out, for example, for 6 hours or more in a desiccator preheated to 40°C.

In one example, the pretreatment material of the first pretreatment aqueous solution is a material that exhibits basic or acidicity in an aqueous solution state and removes a hydrophobic group while minimizing damage to the kapok fiber, and specifically, the pretreatment material of the first pretreatment aqueous solution is periododine. Sodium acid, sodium carbonate, iron sulfate, hydrochloric acid, chloroform, ethanol, sodium hypochlorite, sodium chlorite, hydrogen peroxide, sodium perborate, sodium percarbonate, acetic acid, potassium permanganate, sodium itionate, sulfur dioxide, sodium hydrogen sulfite, hydrosulfite It may include at least one selected from the group consisting of, and preferably, the pretreatment material of the first pretreatment aqueous solution may be sodium hypochlorite.

In another example, the pretreatment material of the first pretreatment aqueous solution may not contain sodium hydroxide. Sodium hydroxide is not suitable because it causes excessive damage and yellowing of kapok fibers.

The pretreatment material of the second pretreatment aqueous solution may include a vegetable polysaccharide-based natural polymer, a marine-derived natural polymer, or an animal protein-based natural polymer.

Examples of the plant polysaccharide-based natural polymer include guar gum, gum arabic, and starch, and examples of marine-derived natural polymers include alginic acid, xanthan gum, chitin/chitosan, and hyaluronic acid, and animal protein-based natural polymers are Gelatin, casein, collagen, and the like are exemplified.

Preferably, the pretreatment material of the second pretreatment aqueous solution may be gelatin. The gelatin is an derived protein obtained by partial hydrolysis of collagen and contains essential amino acids excluding tryptophan and cystine. Gelatin is a peptide bonded to about 1000 amino acids. In particular, the kapok fiber mixed with an aqueous gelatin solution and reacted at room temperature may have an amino acid peptide bonded to the surface thereof, and an amide group may be imparted to the surface of the kapok fiber. The aforementioned hydrophilic group may be, for example, an amide group. The kapok fiber to which an amide group is imparted greatly improves hydrophilicity, and also has excellent dyeability and water absorption.

In addition, the second pretreatment aqueous solution is prepared by dissolving a natural polymer material in water under heating conditions, for example, by heating to a temperature in the range of 40°C to 80°C and dissolving it, and then leaving it at room temperature to prepare.

In one example, the concentration of the first pretreatment aqueous solution is 1 to 20%, 1 to 15%, 1 to 10%, 1 to 9%, 1 to 8%, 1 to 7%, 1 to 6% or 1 to May be within the 5% range. The kapok fiber obtained by heat-treating the first mixed solution mixed with the first pretreatment aqueous solution within the above concentration range exhibits a low weight reduction rate, and thus the strength of the obtained kapok fiber is reduced.

In another example, the pH of the first pretreatment aqueous solution within the concentration range may be in the range of 9 to 13. The first pretreatment aqueous solution within the pH range may exhibit basicity. When the pH of the aqueous solution is basic, the kapok fiber swells, and while the wax is removed from the surface, damage is applied to the surface and the hollow, thereby causing physical deformation. While acetyl groups such as lignin, hemicellulose, and fat are removed by such physical modification, hydroxyl groups (OH-) may be exposed to improve the absorbency of the kapok fibers.

In one embodiment, removing the hydrophobic group of the kapok fiber may include adjusting the pH of the heat-treated first mixed solution. For example, in the step of adjusting the pH, the pH of the first mixture may be adjusted to neutral by adding a weakly acidic substance. The step of adjusting the pH is to prevent excessive damage to the kapok fiber by adjusting the pH of the first mixture to neutral. Further, the first mixed solution whose pH is adjusted to be neutral is washed with water and dried to obtain kapok fibers from which the hydrophobic group has been removed.

In one example, the heat treatment of the first mixture may be performed for 5 to 30 minutes, 10 to 25 minutes, or 15 to 20 minutes within a temperature range of 50 to 150°C, 60 to 120°C or 80 to 100°C. have. By heat treatment within the above temperature and time range, the hydrophobic group of the kapok fiber can be effectively removed.

On the other hand, since the second pretreatment aqueous solution lowers the whiteness of the kapok fiber due to the natural polymer, it is preferable to select and use an appropriate concentration. For example, the concentration of the second pretreatment aqueous solution is 0.01 to 5%, 0.01 to 4%, 0.01 to 3%, 0.01 to 2%, 0.01 to 1.5%, 0.01 to 1.0%, 0.01 to 0.5%, 0.05 to 2%, 0.05 to 1.5%, 0.05 to 1%, 0.05 to 0.5%, 0.1 to It may be in the range of 2%, 0.1 to 1.5%, 0.1 to 1%, or 0.1 to 0.5%.

In another example, the manufacturing method according to the present application may have a weight reduction ratio of less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, or less than 5% according to Formula 1 below.

[General Formula 1]

In General Formula 1, W _a is the weight of the untreated kapok fiber, and W _b is the weight of the kapok fiber to which a hydrophilic group is imparted.

As the value of the weight reduction rate according to Formula 1 is lower, the prepared hydrophilic kapok fiber may exhibit a lower strength decrease.

The present application also relates to a hydrophilic kapok fiber produced according to the method described above. The kapok fiber does not cause fiber damage, strength reduction, and yellowing problems, has excellent whiteness, and has excellent hydrophilicity and moisture absorption (wetability).

The present application provides a method of manufacturing a hydrophilic kapok fiber having excellent wettability and water absorption of a surface without damage and yellowing of the fiber, and a hydrophilic kapok fiber produced thereby.

1 is a flowchart of a manufacturing method according to the present application.
2 to 16 are diagrams showing results of measuring various physical properties of composition examples.

Hereinafter, the above-described contents will be described in more detail through Examples and Comparative Examples. However, the scope of the present application is not limited by the following examples.

Preparation Example 1 - Preparation of Kpok Fiber Aqueous Solution

An aqueous solution of kapok fibers was prepared so that 3 g of untreated kapok fibers satisfying the physical properties of Table 1 were added to a 1 L beaker in a liquid ratio of 1:100.

In Table 1, the length of the kapok fiber was obtained by re-averaging and standard deviation of one strand three times after collecting 0.1 g of the fiber. In addition, the weight is the weight of the fiber from which all skin and impurities were removed after 3g was quantified, and this was measured three times to show the average and standard deviation. Hollow rate is a value calculated as a percentage by dividing the total diameter (S) of the kapok fiber by the hollow length (s) of the kapok fiber, and the length of S of the untreated kapok fiber is 4.8um, the length of s It was 3.6um, and the hollow ratio was calculated as 75%.

Preparation Example 2 - Preparation of sodium hypochlorite aqueous solution

Prepare samples of 1%, 2%, 3%, 4%, 5% sodium hypochlorite aqueous solution (hereinafter, referred to as NaClO for convenience) by mixing 100 ml of distilled water and 1g, 2g, 3g, 4g, 5g of sodium hypochlorite, respectively I did.

Table 2 below shows the pH of NaClO for each concentration.

NaClO stock solution had a strong alkalinity with a pH of 14, and when NaClO 1% was added to distilled water, the pH decreased to 10 and decreased by about 29%. The pH of NaClO from 3% to 5% was 12, which was about 14% lower than that of the stock solution.

Preparation Example 3 -Preparation of aqueous gelatin solution

At 60°C temperature, 0.1g, 0.2g, 0.3g, 0.4g, 0.5g of gelatin is dissolved in 100ml of distilled water, and then left at room temperature for 24 hours to 0.1%, 0.2%, 0.3%, 0.4%, 0.5 % Aqueous gelatin solution samples were prepared.

Table 3 below shows the pH of the gelatin aqueous solution for each concentration.

All gelatin aqueous solutions showed neutral values, and the pH decreased as the amount of gelatin added increased.

Example

The aqueous solution of the kapok fiber prepared in Preparation Example and 1% NaClO were mixed and stirred, followed by heating at 80°C for 15 minutes. Then, after adjusting to neutral pH using 1% acetic acid aqueous solution, it was washed with water and dried for 24 hours in a desiccator preheated to 40 °C to obtain kapok fibers from which hydrophobic groups were removed.

1 g of the kapok fiber from which the hydrophobic group was removed was reacted with 0.1 to 0.5% gelatin aqueous solution at room temperature for 1 hour. After that, in order to remove the slippery touch imparted by gelatin, it was washed with water for 5 minutes, and dried in a desiccator preheated to 40 °C for 6 hours or more to obtain hydrophilic kapok fibers.

In the following, various physical properties of the composition of the examples were measured.

Experimental Example 1- Changes in whiteness of kapok fibers according to treatment with aqueous sodium hypochlorite solution and aqueous gelatin solution

When the sodium hypochlorite aqueous solution was applied to the kapok fiber, it was expected that whiteness could be improved, and the change in the whiteness of the kapok fiber was observed. Specifically, after treatment with 1 to 5% sodium hypochlorite aqueous solution and 0.1 to 0.5% gelatin aqueous solution, the change is compared with the raw material as L* value using a color difference meter (Color Reader, CR-10, Konica Minolta, USA). Comparison was made, and the results are shown in FIG. 2.

A Study on the Changes in Whiteness of Kapok Fibers by Treatment with Sodium Hypochlorite Aqueous Solution and Gelatin Aqueous Solution

Referring to FIG. 2, it was confirmed that the whiteness was generally higher than that of the untreated kapok fiber because the gelatin aqueous solution was treated in the kapok treated with NaClO 1%. The whiteness tended to be slightly lower except for 86.18, which is the L* value of Kpok treated with 0.1% gelatin solution. The whiteness of the kapok treated with 0.3 to 0.5% gelatin aqueous solution decreased to an L* value of 82 to 81, but the whiteness was higher than that of the untreated kapok.

Experimental Example 2 Weight reduction rate according to treatment of aqueous sodium hypochlorite solution and aqueous gelatin solution

After quantifying 3 g of kapok, an aqueous sodium hypochlorite solution was treated for each concentration, and dried for 24 hours in a desiccator preheated to 40 °C. The weight reduction rate was expressed as a percentage by comparing the weight before and after drying and substituting it into the equation below. After that, the gelatin aqueous solution was treated on the kapok treated with 1% NaClO, and dried for more than 6 hours in a desiccator preheated to 40 ° C. The kapok fiber treated with an aqueous gelatin solution was also substituted into the following equation to determine the weight reduction rate. This experiment was repeated three times to obtain the mean and standard deviation, and the results are shown in FIGS. 3 and 4, respectively.

A Study on the Weight Reduction Rate by Treatment of Sodium Hypochlorite Aqueous Solution

3 is a table and a figure showing the weight reduction rate according to the NaClO concentration of the kapok fiber. The raw material kapok was 3g, and the weight reduction rate was calculated based on this. As the NaClO concentration increased, the weight reduction rate increased, and at a concentration of 5%, the weight loss decreased from 3g to 2.43g, resulting in a weight loss of about 18%. In this study, the sample with the least weight loss was at a concentration of 1%, and 0.3g was reduced, resulting in a weight loss of about 10%.

Investigation of weight reduction rate according to gelatin aqueous solution treatment

4 is a table and diagram showing the weight reduction rate according to the gelatin aqueous solution treatment. The weight reduction rate was calculated based on 1 g of kapok treated with 1% NaClO. The weight of the kapok after the gelatin aqueous solution treatment was also slightly reduced, but there was no significant difference. The samples with the least reduction were 0.1% and 0.4% gelatin aqueous solutions, with a slight decrease of 0.04 g. The weight loss of 0.5%, which had the highest concentration, was the greatest, but it was insignificant at 6% and 0.06g. Accordingly, since the gelatin aqueous solution treatment was not subjected to heat treatment like NaClO treatment, it was judged that the weight reduction rate was small, and the strength reduction was also thought to be small.

Experimental Example 3- Morphological analysis according to treatment of aqueous sodium hypochlorite solution and aqueous gelatin solution

Samples were prepared using an ion sputter coater (E-1030, Hitachi, Japan) to see changes in the surface and hollow structure of the kapok fibers treated with NaClO, NaClO 1% and gelatin aqueous solution, and the untreated kapok fibers. It was vacuum deposited. After pretreatment of the sample, a voltage of 15 kV was applied using FE-SEM/EDS (Field emission Scanning Electron Microscope, S-4200, Hitachi, Japan) to observe the surface and hollows of 100 times, 3000 times, and 3500 times of the sample.

Morphological Analysis of Sodium Hypochlorite Aqueous Solution Treatment

1, 3, 5% NaClO-treated kapok fibers and untreated kapok fibers are enlarged 100 times in the form of the results are shown in FIG. In the case of the untreated kapok fiber in (a), it maintains a long uncut fiber length. In the case of (b) treated with 1%, the overall bending of the fiber increased due to the alkali treatment, but the degree of damage to the fiber was less than that of 3% and 5%. In the case of 3% treatment (c), the bending increased and cut, resulting in shorter fiber length. In the case of 5% treatment (d), most of the fibers were cut, so that long fiber lengths such as untreated kapok fibers were not observed. In addition, it is believed that the shape of the fiber is flattened due to physical damage to the hollow due to strong alkalinity.

6 is a result of the surface enlarged 3000 times of the untreated kapok fiber and the kapok fiber after treatment. As shown in (a) of FIG. 6, the untreated kapok had some wrinkles as well as after treatment, but it could be observed that it was less than after treatment. Untreated kapok fibers are less damaged than NaClO-treated kapok fibers. After NaClO treatment, it was confirmed that cracks and wrinkles were further formed on the surface of the kapok fibers due to deformation, and the fibers were swollen due to alkali treatment. In 1% of FIG. 6(b), compared to 3% of FIG. 6(c) and 5% of FIG. 6(d), it was confirmed that the long fiber had the least rough surface. In Figures 6 (c) and (d), it was possible to see the swelling, but it was confirmed that the roughness was increased because the surface was severely damaged. This is expected to decrease the strength, and in the case of FIG. 6 (d), it was observed that the furrow was formed. This tendency could also be observed in FIG. 7, and it was confirmed that the higher the concentration, the higher the strength was cut due to the decrease in strength.

7 is a result of examining the hollow structure by expanding 3,500 times of the untreated kapok fiber and the treated kapok fiber. In the case of the untreated kapok fiber, the hollow is large, which is consistent with previous studies. As shown in Fig. 7(a), the hollow is large and has a shape close to a circle. 7 (b) is a result of the hollowing after the 1% treatment, it can be observed a vertically elongated appearance, that is, the hollow is reduced. It is believed that this can reduce the property of floating on water. 7 (c) and 7 (d) showed that the damage of the hollow portion was observed as 1% as a result of the treatment of 3% and 5%, but rather, the deformation of the hollow was clearly observed at 1%. Accordingly, it was confirmed that NaClO 1% has the most excellent solubility in water and is an appropriate treatment standard.

A Study on Morphological Changes According to Gelatin Aqueous Treatment

Figure 8 is a 100-fold magnification of the kapok fiber treated with 1% NaClO and 0.1% and 0.5% aqueous gelatin solution. In both results, the degree of damage to the fibers was reduced by treatment with 1% NaClO. However, by treating the aqueous gelatin solution, the overall fiber width was increased compared to the result of NaClO treatment. This is commonly believed to be a result of the effect of gelatin's swelling properties on the kapok fibers by treating an aqueous gelatin solution at room temperature. Therefore, it was confirmed that by treating the kapok fiber treated with 1% NaClO with an aqueous gelatin solution, the width of the fiber expands, so that the wettability can be improved and strength deterioration can be prevented.

9 is a view magnified 3000 times by treating the kapok fiber treated with 1% NaClO with an aqueous solution of 0.1 and 0.5% gelatin. Both samples were treated with an aqueous gelatin solution to observe gelatin adhesion. The 0.1% aqueous gelatin solution treatment had a lower concentration, but the surface was swollen than the 0.5% aqueous gelatin solution treated kapok fiber. This is because 0.5% gelatin was not dissolved in water when the aqueous gelatin solution was prepared, and thus did not adhere to the surface when stirred at room temperature.

Figure 10 is a result of examining the hollow structure of the kapok fiber treated with 1% NaClO 1%, 0.1%, 0.5% gelatin aqueous solution, and the hollow structure of the kapok fiber was enlarged 3500 times. Since (a) and (b) treated with 1% NaClO, it was confirmed that the shape of the hollow was deformed as shown in FIG. 9 (b). Although the aqueous gelatin solution was stirred at room temperature and washed with water, it was confirmed that an uneven surface was formed as the aqueous gelatin solution was fixed to the surface.

Experimental Example 4 FT-IR analysis according to the treatment of aqueous sodium hypochlorite and aqueous gelatin solution

FT-IR (Spectrum 100, Perkin Elemer, USA) was used in a nitrogen atmosphere in a wavelength range of 600 to 4000 cm ^-1 in order to check whether the chemical composition of kapok fiber was treated with NaClO or gelatin aqueous solution, and whether the hydrophobic acetyl group was removed. Measured.

Consideration of FT-IR analysis according to sodium hypochlorite aqueous solution treatment

11 and Table 4 are FT-IR analysis results to determine whether or not hydrophobic groups are removed by NaClO treatment of kapok fibers.

Untreated kapok fiber is 3343cm ^-1 -OH stretch, 2917cm ^-1 vegetable wax CH vibration, 1736cm ^-1 lignin, aliphatic aldehyde, ester, ketone equivalent C=O stretch, 1594cm ^-1 is lignin and fat C= C stretch, 1423cm ^-1, 1371cm ^-1, CH bending, CH bend of hemicellulose corresponding to 1239cm ^-1, 1035cm ^-1 carbohydrates, 898cm ^-1 β- glycoside of which corresponds to the combination of lignin of 1319cm ^-1 It was possible to identify peaks that impart hydrophobicity, such as CH stretch and -OH of 607 cm ^-1 , and some hydrophilic peaks. Treatment with an alkali such as NaClO can remove the acetyl group, which is a hydrophobic group such as lignin, wax, and oil components, and the FT-IR results showed that the hydrophobic group disappeared. In the sample treated with NaClO of 1594cm ^-1 of fat C = C functional group that corresponds to the vegetable waxes, lignin 2917cm ^-1 1423cm ^-1, 1319cm ^-1 CH lignin and β- glycoside of 898cm ^-1 of the bend corresponding to the The peaks of CH stretching of the bond disappeared at all three concentrations: 1, 3, and 5%. Therefore, with alkali treatment such as NaClO, wax and fat on the surface completely disappear and many lignin are removed, but unlike NaOH, which is representative of alkali, can remove hemicellulose of kapok, NaClO has a great effect on hemicellulose. I could see that I was not crazy Among the samples treated with NaClO, only the sample treated with 3% of the hydrophilic groups such as 607.83cm ^-1 disappeared, and only the sample treated with 5% NaClO disappeared the peak of the CH bending of 1371cm ^-1 of lignin, resulting in NaClO The higher the concentration of, the more lignin can be removed, but the hydrophilic peaks such as -OH stretch are reduced the most, and it was confirmed that the removal of the hydrophilic group also occurred in 3% and 5% compared to 1%. Therefore, by treatment with NaClO, some lignin and hemicellulose exist, but hydrophobic peaks, especially waxes and fats, were reduced, indicating that the hydrophilicity was increased. It was confirmed that it was a suitable treatment concentration in which the hydrophobic peak disappeared while the most hydrophilic group was maintained.

Consideration of FT-IR analysis according to gelatin aqueous solution treatment

12 and Table 5 show the results of confirming whether peaks of amide groups were formed when a 0.1% and 0.5% aqueous gelatin solution was stirred at room temperature, respectively, to kapok fibers treated with NaClO 1%.

Gelatin is an derived protein obtained by partial hydrolysis of collagen and contains all essential amino acids except tryptophan and cystine. Collagen is a peptide bond of about 1000 amino acids, and if the gelatin aqueous solution is treated, peptide bonds can be applied to the kapok surface, which is consistent with the results. Gelatin had an amide group peak of 1646cm ^-1 and C=O Stretching in previous studies. It was confirmed that a peak of 1646.31cm ^-1 was formed in the kapok treated with 0.1% gelatin aqueous solution, and through this, it could be inferred that the 0.1% gelatin aqueous solution had a peptide bond formed on the kapok surface. It is possible to support that the 0.1% gelatin aqueous solution showed a tendency toward unevenness and thickening of the fiber surface than the 0.5% gelatin aqueous solution which was uniformly shown in SEM. Accordingly, when the gelatin aqueous solution was prepared, it was found that in the case of 0.5%, it was difficult to disperse in water and the treatment effect was also insufficient. It could be expected that 0.1% gelatin aqueous solution could increase the dyeing property and absorption performance by imparting an amide group to the kapok fiber.

Experimental Example 4 Drying speed test method according to treatment of aqueous sodium hypochlorite solution and aqueous gelatin solution

As for the drying rate test method, KS K 0815: 2008. 6. 28. 1 B method [24] was used to confirm the change in moisture content in the fibers of untreated kapok fibers, NaClO treated kapok fibers, and kapok fibers treated with NaClO 1% and gelatin aqueous solution. did. In this test method, 0.5 g of each sample is immersed in distilled water for at least 3 hours, taken out, and then naturally dried for 10 minutes, and the difference value obtained by subtracting the weight of the sample before immersion is expressed as the result value (g). It was judged that the smaller the result value, the faster the drying rate was and the less moisture content in the fiber. The above experiment was repeated 3 times to obtain the mean and standard deviation values.

A Study on the Change of Moisture Content in Fibers by Treatment with Sodium Hypochlorite Aqueous Solution

13 is the weight after the drying rate test method of the untreated kapok fiber and the kapok fiber treated with each concentration of NaClO, respectively. According to the drying rate test method, when immersed in water for 3 hours and then dried for 10 minutes, the heavier the weight, the more moisture in the fiber could not escape, so it was judged that the content was higher. Untreated kapok was not immersed in water due to its hydrophobic nature, so the weight after drying was the lightest. This shows that no moisture penetrates into the fibers. However, it was immersed in water according to the treatment of NaClO, and the weight increased rapidly by more than 10g. It is believed that the decomposition of hydrophobic groups containing alkyl groups such as lignin and fat due to NaClO and heat treatment and the loss of wax components on the surface of kapok, resulting in decreased oil adsorption, resulting in increased moisture content. At all concentrations, the weight after treatment increases sharply rather than untreated, but when the concentration of 1% NaClO is exceeded, the weight gradually decreases and decreases the most at 5%. This means that as the concentration of NaClO increases, the moisture content in the fiber decreases. In the case of 5% of the overconcentration, not only the hydrophobic group but also the hydrophilic group decreased, and thus the moisture content decreased.

Moisture Content Changes in Fibers According to Gelatin Aqueous Treatment

The result of treatment with the aqueous gelatin solution after NaClO treatment is shown in FIG. 14. Unlike the NaClO treatment, the aqueous gelatin treatment did not seem to have a significant correlation with the concentration, and the moisture content was the highest at 0.2%, 0.5%, and 0.1%. In the case of 0.2%, 0.5% gelatin aqueous solution treatment, the moisture content is about 10% higher than that of NaClO 1% treatment. However, the 0.3% and 0.4% gelatin aqueous solution treatment except this showed less moisture content. It was confirmed that the treatment conditions of a suitable aqueous gelatin solution after NaClO treatment were 0.1%, 0.2% and 0.5%.

Experimental Example 5- Evaluation of hydrophilicity of kapok fiber by dyeing

Untreated kapok fibers, NaClO-treated kapok fibers, and kapok fibers treated with 1% NaClO and an aqueous gelatin solution were dyed with natural extracts to evaluate their hydrophilicity. Each untreated kapok fiber and 1 g of treated kapok fiber were dyed in Gardenia extract for 20 minutes using a Hotplate Stirrer (JSHS-18D, JSR, Korea) at a low temperature of 40 to 60 °C, and the dyeing process is as shown in FIG. After dyeing, it was washed with water at room temperature and dried for more than 6 hours in a desiccator preheated to 40 °C. Colorimetric color values were measured by maintaining the thickness of each sample about 1.5 cm. The color values are the brightness L ^* , color coordinate index a ^* , b ^* values, C, h values and dyeing amount K/S values below 400 nm using CCM (Macbeth, Color-Eye 3100, USA) with a D65 light source and a viewing angle of 10°. Hydrophilicity was evaluated through the average value measured five times under conditions. After that, the H/VC value was calculated by Munsell 8.0 to the measured data, and the ΔE value was calculated by substituting the following General Formula 1.

[General Formula 1]

ΔE = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2

ΔL = L ₁ -L ₂ , Δa = a ₁ -a ₂ , Δb = b ₁ -b ₂

Study on Hydrophilicity of Kapok Fiber by Dyeing

16 and Table 6 show the results of applying a natural extract of gardenia at low temperature to the kapok raw material (untreated kapok fiber), NaClO 1% treatment, NaClO 1% treatment, and then the kapok fiber treated with an aqueous gelatin solution.

As a result of dyeing, at a high temperature such as 70-80°C, since the untreated kapok fiber melted with the dye and the strength decreased, the experiment was conducted at a low temperature of 40-60°C. According to Table 6, the color of the alkaline-treated kapok fibers was the brightest, and when the gelatin aqueous solution was treated, the brightness was lowered and the color became dark. In the case of the kapok raw material, the K/S value was the lowest, and both a* and b* values were low, giving it a pale yellow color. However, since the dye solution did not adhere to the fiber, it was not leveled. Through this, it is thought that some hydrophobic groups remain in the case of the raw material kapok. In the case of alkali treatment and gelatin aqueous solution treatment Kapok, the b* value and C value were improved by about 20, confirming that both were modified to be hydrophilic to a dark yellow color. The samples with the highest b* values were treated with NaClO 1%, 0.1% gelatin aqueous solution, and 0.5% gelatin aqueous solution in the order of treatment, which showed the same tendency for C and h values. Overall, the reason why the gelatin aqueous solution-treated kapok slightly decreases the color value compared to the alkali-treated kapok is considered to be due to the darkening of the fiber color by treating the aqueous gelatin solution. The darkest sample was kapok treated with 0.3% gelatin aqueous solution and showed the lowest color value. As for the K/S value, the raw material Kapok showed the lowest value, but it was observed that the K/S value improved by 3 or more in all samples except the 0.3% gelatin aqueous solution treated Kapok. Showed. This was due to an increase in amide groups and a non-uniform surface confirmed by SEM and FT-IR.

Claims (10)

Preparing untreated kapok fibers;
Preparing a first mixed solution by mixing the untreated kapok fiber and a first pre-treatment aqueous solution containing a pre-treatment material for removing the hydrophobic group of the kapok fiber;
Heat-treating the first mixture to remove hydrophobic groups from the kapok fibers;
Preparing a second mixed solution by mixing the kapok fibers from which the hydrophobic group has been removed and a second pretreatment aqueous solution containing a pretreatment material that imparts a hydrophilic group to the kapok fibers; And
A method for producing a hydrophilic kapok fiber comprising the step of providing a hydrophilic group to the kapok fiber by reacting the second mixture at room temperature. The method of claim 1, wherein the pretreatment material of the first pretreatment aqueous solution is sodium periodate, sodium carbonate, iron sulfate, hydrochloric acid, chloroform, ethanol, sodium hypochlorite, sodium chlorite, hydrogen peroxide, sodium perborate, sodium percarbonate, and peracetic acid. , Potassium permanganate, sodium itionate, sulfur dioxide, sodium hydrogen sulfite, a method for producing a hydrophilic kapok fiber comprising at least one selected from the group consisting of hydrosulfite. The method of claim 1, wherein the pretreatment material of the second pretreatment aqueous solution comprises a vegetable polysaccharide-based natural polymer, a marine-derived natural polymer, or an animal protein-based natural polymer. The method of claim 1, wherein the concentration of the first pretreatment aqueous solution is in the range of 0.1 to 20%. The method of claim 1, wherein the pH of the first pretreatment aqueous solution is in the range of 9 to 13, hydrophilic kapok fiber. The method of claim 1, wherein the step of removing the hydrophobic group of the kapok fiber,
A method for producing a hydrophilic kapok fiber comprising the step of adjusting the pH of the heat-treated first mixed solution. The method of claim 1, wherein the heat treatment of the first mixed solution is performed for 5 to 20 minutes in a temperature range of 50 to 150°C. The method of claim 1, wherein the concentration of the second pretreatment aqueous solution is in the range of 0.01 to 5%. The method of claim 1, wherein the weight reduction rate according to the following general formula 1 is less than 10%:
[General Formula 1]

In General Formula 1, W _a is the weight of the untreated kapok fiber, and W _b is the weight of the kapok fiber to which a hydrophilic group is imparted. Hydrophilic kapok fiber produced by the manufacturing method according to claim 1.

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