Production method for fiber coating agent, production method for coated fiber, coated fiber and coated fiber cloth

Abstract

To provide a coated fiber cloth which is a functional fabric having the properties of base fiber combined with the properties of nanocellulose through coating the fiber with nanocellulose.SOLUTION: A coated fiber comprises nanocellulose and a fiber, characterized by the surface of the coated fiber being coated with nanocellulose. The nanocellulose is derived from a sea squirt shell or green algae. The tensile strength is improved by 20% or more compared to the tensile strength of the fiber.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a fiber coating agent containing nanocellulose, a coated fiber coated with the fiber coating agent, and a coated fiber fabric using the coated fiber.

Background Art

[0002] In the apparel industry, in response to the increasing number of people who enjoy fashion and the outdoors, there has been a growing demand for functional fabrics that combine the characteristics of the base fiber with other characteristics. For example, fabrics that have the luster of silk while being made of cotton, fabrics that reduce the prickly feeling while being made of wool, fabrics that feel warm when worn while not being made of animal hair, fabrics that combine strength and design, and the like.

[0003] However, when trying to produce the above functional fabrics by improving the base fibers themselves (such as cotton, animal hair, polyester, acetate, polyurethane, etc.), it is necessary to consider chemical substitution of the functional groups that make up each fiber, or to consider the weaving method of the fabric and the mixing ratio of the fibers (Patent Documents 1, 2, etc.). For this reason, there are problems such as the development and research costs for each type of functional fabric are high, the process becomes complicated, and the functional fabric to be produced becomes expensive.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention is made in view of the above circumstances, and an object thereof is to provide a coated fiber fabric, which is a functional fabric that combines the characteristics of nanocellulose with those of the base fiber by coating the base fiber with nanocellulose. Another object is to provide a fiber coating agent and coated fibers used for the above coated fiber fabric.

Means for Solving the Problems

[0006] In order to solve the above problems, a method for manufacturing a fiber coating agent of the present invention includes the steps of adding eggshells to a mixed solution of sodium hypochlorite / sodium hydroxide and wet pulverizing; allowing the pulverized eggshells to stand in the mixed solution for decomposition treatment; washing the decomposed eggshells to separate eggshell nanocellulose; and dispersing the separated eggshell nanocellulose in water.

[0007] In the step of dispersing in water, it is desirable that the content of the eggshell nanocellulose is 0.3 g / L to 5.0 g / L with respect to the water.

[0008] A method for manufacturing a coated fiber of the present invention includes the steps of coating a fiber using the fiber coating agent manufactured by the method for manufacturing a fiber coating agent described above, and drying the coated fiber.

[0009] The coated fiber of the present invention contains nanocellulose and a fiber, and is characterized in that the surface of the fiber is coated with the nanocellulose.

[0010] The nanocellulose may be derived from eggshells or green algae.

[0011] It is desirable that the tensile strength of the coated fiber is improved by 20% or more compared to the tensile strength of the fiber.

[0012] The coated fiber fabric of the present invention is characterized by using the above-mentioned coated fibers.

[0013] It is desirable that the temperature in the moisture absorption and heat generation test of the coated fiber fabric has a maximum temperature difference of 0.5 °C or more with respect to the temperature in the moisture absorption and heat generation test of the uncoated fiber fabric.

Effects of the Invention

[0014] With the coated fiber fabric of the present invention, by coating the base fiber with nanocellulose, it is possible to provide a coated fiber fabric, which is a functional fabric that combines the characteristics of nanocellulose with the characteristics of the base fiber without complicating the process. In addition, the coated fiber of the present invention can improve the tensile strength and provide gloss compared with the uncoated fiber. Furthermore, the coated fiber fabric of the present invention can improve the moisture absorption and heat generation property compared with the uncoated fiber fabric.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0016] (Method for Producing Fiber Coating Agent) The method for producing the fiber coating agent of the present invention includes a step of wet-grinding eggshells, a step of decomposing the ground eggshells, a step of washing the decomposed eggshells and separating eggshell nanocellulose, and a step of dispersing the separated eggshell nanocellulose in water. The outline of the process is shown in Fig. 1.

[0017] Cellulose is a polysaccharide and a natural polymer in which β-glucose polymerizes linearly. Since it exists abundantly in nature, it is used in various fields such as paper, dietary fiber, and regenerated fiber. Nanocellulose is obtained by defibrating cellulose to the nanoscale. As the name implies, the diameter of nanocellulose is generally on the order of nanometers, and often refers to materials with a size of 100 nm or less. The length of nanocellulose is generally 1 μm or more, or 5 μm or more.

[0018] Types of nanocellulose include plant nanocellulose such as wood, crystalline nanocellulose (cellulose nanocrystal), bacterial nanocellulose, etc. As analogs of nanocellulose, chitin nanofibers, etc. are known. What is spun from nanocellulose is nanocellulose fiber.

[0019] In the method for producing a fiber coating agent, eggshells are used as a raw material for nanocellulose. Since the eggshell nanocellulose contained in eggshells is a type of bacterial nanocellulose, it is only necessary to wet-mill the eggshells. This is because bacterial cellulose can be defibrated into bacterial nanocellulose by wet-milling, as the fine fibers secreted by microorganisms form a fine network structure as they are. Note that since plant-derived cellulose has fine fibers arranged orderly and crystallized into bundles, defibrillation is insufficient by wet-milling. To obtain plant nanocellulose, it is necessary to apply tough physical milling, high-pressure homogenizer method, high-shear force kneading method, ball milling method, etc. for defibrillation.

[0020] The wet-milling of eggshells can be carried out by adding eggshells to a mixed solution of 4% - 8% sodium hypochlorite / sodium hydroxide and subjecting them to a grinding tester. More preferably, a mixed solution of 6% sodium hypochlorite / sodium hydroxide is used. The ratio of sodium hypochlorite:sodium hydroxide is preferably adjusted in the range of 5:1 to 9:1.

[0021] By allowing the crushed oyster shells to stand as they are in the above mixed solution, the decomposition treatment is carried out. The sodium hypochlorite / sodium hydroxide 6% mixed solution has the same component concentration as a commercially available bleaching agent and can decompose proteins and the like contained in the oyster shells. The standing time is appropriately set according to the decomposition status of components other than the cellulose of the oyster shells, and examples include 2 days to 4 weeks, about 1 week to 2 weeks.

[0022] By repeating the centrifugation of the decomposed oyster shells and washing with pure water, oyster nanocellulose is separated. In order to wash out the mixed solution of sodium hypochlorite / sodium hydroxide, it is preferable to perform washing with pure water a plurality of times.

[0023] The separated oyster nanocellulose is dispersed in water so as to reach a predetermined concentration (content). The content of oyster nanocellulose in the water is appropriately set according to the type, diameter, surface state, etc. of the fibers to be coated, but is preferably 0.3 g / L or more, more preferably 0.5 g / L or more, still more preferably 0.6 g / or more, or 0.8 g / L or more. If the concentration is too low, it will not be possible to sufficiently coat the surface of the fibers to be coated. Also, if the concentration is too high, there will be too much oyster nanocellulose for the fibers to be coated, the viscosity of the fiber coating agent will become too high and precipitate, and it will be difficult to balance the characteristics of the base fibers and the characteristics of the oyster nanocellulose. Therefore, it is preferably 5.0 g / L or less, more preferably 4.0 g / L or less, still more preferably 3.3 g / or less.

[0024] In addition to the oyster nanocellulose dispersed in water, additives commonly used for fiber products may be added to the fiber coating agent in order to impart further characteristics, but it is desirable to adjust so as not to prevent the fiber surface from being sufficiently covered with oyster nanocellulose. A more preferable fiber coating agent consists of fibers and oyster nanocellulose so that the fiber surface can be sufficiently coated with oyster nanocellulose and no other components are added.

[0025] The fiber coating agent is manufactured by the method as described above.

[0026] (Method for manufacturing coated fibers) Coated fibers are manufactured by immersing fibers in the fiber coating agent manufactured by the above method and then drying them.

[0027] Examples of the fibers include natural fibers such as cotton, hemp, linen, silk, wool, and cashmere, synthetic fibers such as polyester, nylon, acrylic, polyurethane, and vinylon, semi-synthetic fibers such as acetate, regenerated fibers such as rayon and cupra, and fibers containing inorganic substances. These fibers may be used alone or blended / twisted with two or more types. The thickness of the fiber is not particularly limited, but a range of 20 denier to 400 denier is exemplified.

[0028] Immerse the above fibers in the fiber coating agent manufactured at a predetermined concentration. The immersion may be performed so that the fiber coating agent coats the fiber surface. Depending on the type and thickness of the fiber, examples include inserting the fiber into the fiber coating agent to several hours of immersion.

[0029] The fibers immersed in the fiber coating agent are dried. Examples of the drying method include natural drying, heat drying, vacuum drying, and vacuum heat drying. The time for natural drying is 2 hours or more, preferably 12 hours or more, more preferably 24 hours or more. The heat drying is appropriately set according to the type and thickness of the fiber, but is preferably performed at 80°C or higher, more preferably 100°C, even more preferably 120°C or higher for several hours. In that case, in a vacuum state, it may be used as vacuum heat drying.

[0030] An example of an optical microscope image of uncoated cotton fibers is shown in Fig. 2(a), and an example of an optical microscope image of cotton fibers coated with the fiber coating agent is shown in Fig. 2(b). From Fig. 2(a), it was found that the cotton fibers used as a comparative control were composed of bundles of a plurality of fine fibers. From Fig. 2(b), it was found that when the cotton fibers were coated with the fiber coating agent, the nacre nanocellulose adhered (coated) so as to wrap around and fill the gaps between the bundles of the plurality of fine fibers.

[0031] (Tensile strength of the coated fibers after natural drying) The tensile strength of the coated fibers preferably increases by 20% or more, and more preferably by 30% or more, compared to the tensile strength of the uncoated fibers.

[0032] The manufacturing method of the above fiber coating agent and the tensile strength test of the coated fibers produced by the manufacturing method of the coated fibers were carried out. The separated nacre nanocellulose was dispersed in water so as to have concentrations of 0 g / L, 0.2 g / L, 0.8 g / L, and 3.3 g / L with respect to water, and a fiber coating agent was prepared. Cotton fibers (150 denier) were passed through each fiber coating agent and naturally dried for 24 hours to obtain coated fibers. Each coated fiber was cut to a length of 3 cm, clamped between the upper and lower clamps of a tensile testing machine, and a tensile test was conducted. At this time, the gap between the upper and lower clamps was set to 1 cm, and the clamps were separated at a speed of 1 to 3 mm per second to measure the tensile strength of the coated fibers.

[0033] The relationship between the nacre nanocellulose concentration (g / L) of the fiber coating agent and the tensile strength (N) of the coated fibers is shown in Table 1 and Fig. 3.

[0034]

Table 1

[0035] From Table 1 and Figure 3, compared with the tensile strength (6.7 N) of cotton fibers without the coating for comparison (Sample 1), the tensile strength of the coated cotton fibers all increased. In particular, in Samples 3 and 4 with a nanocellulose concentration of 0.8 g / L and 3.3 g / L, the tensile strength was 8.8 N, and it was found that the strength was improved by 31.5% compared with Sample 1.

[0036] (SEM image of the coated fiber after vacuum heating and drying) The separated jellyfish nanocellulose was dispersed in water so that the concentration became 3.3 g / L with respect to water to prepare a fiber coating agent. Cotton fibers (150 denier) were passed through the above fiber coating agent and heated and dried under vacuum conditions at 120 °C for 3 hours to obtain coated fibers (Sample 5).

[0037] Figures 4 and 5 show SEM images of the coated fibers (Sample 5) after vacuum drying. Figure 4(a) has a magnification of 1 mm = 100 μm, Figure 4(b) has a magnification of 1 mm = 10 μm, Figure 5(a) has a magnification of 1 mm = 0.4 μm, and Figure 5(b) has a magnification of 1 mm = 100 nm. From Figures 4 and 5, it was found that when cotton fibers were coated with the fiber coating agent and vacuum heated and dried, the jellyfish nanocellulose adhered (coated) so as to wrap around and fill the gaps between the bundles of the plurality of fine fibers. Also, from the high-magnification SEM images such as Figure 5(a) and Figure 5(b), it was found that the jellyfish nanocellulose coating the surface of the cotton fibers had a structure in which a plurality of jellyfish nanocelluloses with a diameter of several tens of nm overlapped like a plurality of meshes.

[0038] (Tensile strength of the coated fiber after vacuum heating and drying) Regarding the coated fibers after vacuum drying obtained by the above method, the tensile strength was similarly measured. Table 2 and Figure 6 show Table 1 and Figure 3 with the data of the tensile strength of the vacuum-dried coated fibers added.

[0039]

Table 2

[0040] From Table 2 and Figure 6, it was found that the tensile strength of the coated fiber (Sample 5) subjected to vacuum drying was 10.4 N, which was 55.8% higher than that of the cotton fiber without the coating for comparison (Sample 1) (6.7 N). Also, compared with the tensile strength of the coated fiber (Sample 4) dried naturally at the same nanocellulose concentration (3.3 g / L) (8.8 N), the tensile strength of the coated fiber (Sample 5) subjected to vacuum drying was found to be 18.5% higher.

[0041] After the nacre nanocellulose adhered between the bundles of microfibers constituting the cotton fiber and then vacuum heating and drying were performed, it is considered that the moisture was further removed and the adhesion strength of the nacre nanocellulose increased.

[0042] (SEM image of the coated fiber after ultrasonic cleaning) Since the coated fiber is used as an apparel material, it is required to have the property that the coated nacre nanocellulose is not easily peeled off even after washing. Therefore, the coated fiber (Sample 5) after vacuum heating and drying was ultrasonically cleaned in water for 10 minutes and then naturally dried to obtain Sample 6.

[0043] Figures 7 and 8 show the SEM images of the coated fiber (Sample 6) after ultrasonic cleaning - natural drying. Figure 7(a) has a magnification of 1 mm = 100 μm, Figure 7(b) has a magnification of 1 mm = 10 μm, Figure 8(a) has a magnification of 1 mm = 0.4 μm, and Figure 8(b) has a magnification of 1 mm = 200 nm. From Figures 7 and 8, it was found that even after ultrasonic cleaning, a large amount of nacre nanocellulose was adhered (coated) to the cotton fiber. Also, from the high - magnification SEM images such as Figure 8(a) and Figure 8(b), it was found that the nacre nanocellulose coating the surface of the cotton fiber had a structure in which nacre nanocelluloses with a diameter of several tens of nm overlapped like multiple meshes, and there was almost no change compared with before ultrasonic cleaning.

[0044] (Tensile Strength of Coated Fibers after Ultrasonic Cleaning) Three samples were prepared: uncoated cotton fibers for comparison (Sample 1), cotton fibers coated with a fiber coating agent with a nano-cellulose concentration of 3.3 g / L and air-dried (Sample 4), and cotton fibers coated with a fiber coating agent with a nano-cellulose concentration of 3.3 g / L and vacuum-heat-dried (Sample 5). These three samples were ultrasonically cleaned in water for 10 minutes and then dried, obtaining Samples 7, 8, and 6 respectively.

[0045] The tensile strengths of Samples 7, 8, and 6 were measured in the same way. The tensile strengths of the ultrasonically cleaned coated fibers are shown in Figure 9 and Table 3.

[0046]

Table 3

[0047] In Figure 9, (a) represents the data of Sample 7, (b) represents the data of Sample 8, and (c) represents the data of Sample 6. Compared with the tensile strength of Sample 7 (7.3 N) of the uncoated cotton fibers dried after ultrasonic cleaning, the tensile strength of Sample 8 was 10.0 N, indicating a 36.4% improvement compared to Sample 7. Also, the tensile strength of Sample 6 was 9.4 N, indicating a 28.7% improvement compared to Sample 7.

[0048] It was found that the fibers once coated with oyster nano-cellulose still had sufficient oyster nano-cellulose adhered to the surface even after cleaning, and the tensile strength hardly decreased.

[0049] (Coated Fibers) In the above manufacturing method of the fiber coating agent and the manufacturing method of the coated fibers, a manufacturing method specialized for the case of using oyster shells as raw materials has been described. However, the raw material of the nano-cellulose used in the coated fibers is not limited to oyster shells and may also be green algae, etc.

[0050] The coating fiber of the present invention contains nanocellulose and a fiber, and the surface of the fiber is coated with the nanocellulose.

[0051] Examples of the nanocellulose include plant nanocellulose such as wood, crystalline nanocellulose (cellulose nanocrystal), bacterial nanocellulose such as ascidian nanocellulose, and chitin nanofiber as an analog of nanocellulose. Among them, the nanocellulose is preferably ascidian nanocellulose because physical pulverization that is tough against fibrillation is not required, it is a kind of bacterial nanocellulose, has a thin diameter and a long fiber length (high aspect ratio), and the variation in aspect ratio is smaller than that of plant nanocellulose. A large aspect ratio and a small variation in aspect ratio (no short fibers are mixed) can improve the gloss of the fiber after coating. When the nanocellulose is ascidian nanocellulose, it may be produced according to the above-described method for producing a fiber coating agent. When the nanocellulose is plant nanocellulose, a tough physical pulverization, a high-pressure homogenizer method, a high-shear kneading method, a ball milling method, etc. may be applied, or a chemical treatment such as TEMPO oxidation method may be applied to produce a fiber coating agent.

[0052] Examples of the fiber include natural fibers such as cotton, hemp, linen, silk, wool, and cashmere, synthetic fibers such as polyester, nylon, acrylic, polyurethane, and vinylon, semi-synthetic fibers such as acetate, regenerated fibers such as rayon and cupra, and fibers containing inorganic substances. These fibers may be used alone or blended / twisted in two or more types. The thickness of the fiber is not particularly limited, but a range of 20 denier to 400 denier is exemplified.

[0053] (Coating fiber fabric) The coating fabric of the present invention is provided by using the above-described coating fiber as a part of any fabric such as a woven fabric, a non-woven fabric, or a knitted fabric. Coating fibers can be woven or knitted to obtain a coated fiber fabric. On the other hand, it is also possible to obtain a coated fiber fabric by immersing a fabric woven from uncoated fibers in a fiber coating agent containing nanocellulose.

[0054] (Moisture absorption and heat generation properties of coated fiber fabric) In the moisture absorption and heat generation test of the coated fiber fabric, the temperature is preferably 0.5 °C or higher, more preferably 1.0 °C or higher, still more preferably 1.5 °C or higher, and even more preferably 1.8 °C or higher than the temperature in the moisture absorption and heat generation test of the uncoated fiber fabric. Moisture absorption and heat generation is a property in which fibers generate heat when absorbing moisture. When the maximum temperature difference from a comparative control product is 0.5 °C or more, it is considered to have a significant difference. The mechanism is considered that when water molecules (moisture) in the air are adsorbed on the fiber surface, the kinetic energy of the freely moving water molecules is converted into thermal energy to generate adsorption heat, and the temperature rises primarily.

[0055] Fold a 20 cm × 20 cm test piece into four and attach a thermocouple temperature sensor inside. After treating it in an environment of 20 °C and 40% RH for 2 hours in a thermo-hygrostat, measure the temperature change every 1 minute for 15 minutes when changing to an environment of 20 °C and 90% RH to conduct the test. Measure the temperature of the coated fiber fabric and the uncoated fiber fabric simultaneously and compare the changes over time (tested by the General Incorporated Association Boken Quality Evaluation Organization). Figure 10 and Table 4 show the temperature changes over time.

[0056]

Table 4

[0057] From FIG. 10 and Table 4, it was found that the maximum temperature difference between the temperature of the coated fiber fabric and the temperature of the uncoated fiber fabric is 1.8 °C. This temperature difference is significantly higher than 0.5 °C, which is considered a significant difference, by 1.3 °C. When wearing clothing made of this fabric, it is predicted that the perceived temperature will feel 5 to 8 °C warmer than the comparative control product made of uncoated fiber fabric. That is, it was found that clothing made of the coated fiber fabric also has a remarkable effect on heat retention.

[0058] (Gloss comparison test of coated yarn) A gloss comparison test was conducted when cotton yarn was passed through nanocellulose, immersed, and dried. FIG. 11 shows a photograph when using a yarn with a thickness of 30 count, a nanocellulose concentration of 1%, and drying at 70 °C for 10 minutes. As a comparative example, FIG. 12 shows a photograph of cotton yarn in a state of not being immersed in nanocellulose.

[0059] From FIGS. 11 and 12, it was found that coating the yarn with nanocellulose gives gloss. It was also confirmed that equivalent gloss can be obtained when changing the thickness of the yarn or changing the nanocellulose concentration to 10% or the like.

Industrial Applicability

[0060] The coated fiber and coated fiber fabric of the present invention are functional fibers and functional fabrics that exhibit effects such as improved strength of the coated fiber including the above-described characteristics because nanocellulose is strongly bonded to the surface of the fiber, the strength of the coated fiber hardly changes even after ultrasonic cleaning, high moisture absorption and heat generation properties resulting in a high perceived temperature, improved strength even with a thin fabric, obtaining a lightweight material, obtaining a gloss and texture like silk due to coating with nanocellulose, suppressing the fuzziness of cotton fibers, and suppressing the prickly feeling of wool. In addition, when the fiber coating agent and coated fiber of the present invention are made from oyster shells, the discarded parts of edible oysters can be effectively utilized. Also, since oyster nanocellulose is of natural origin, it is biodegradable, and the fiber coating agent and coated fiber are environmentally friendly. Furthermore, since the above effects can be exhibited without adding chemical substances other than oyster nanocellulose and water to the fiber coating agent, it is expected to be widely applied in the future as an effective fiber coating agent that is cost-effective.

Claims

1. Adding sea squirt shells to a mixed solution of sodium hypochlorite / sodium hydroxide and wet grinding; A step of placing the crushed sea squirt shell in the mixed solution to decompose it; A step of washing the decomposed sea squirt shell and separating the sea squirt nanocellulose; Dispersing the separated sea squirt nanocellulose in water; A method for producing a fiber coating agent, comprising:

2. The method for producing a fiber coating agent according to claim 1, wherein the content of the sea squirt nanocellulose in the water is 0.3 g / L to 5.0 g / L in the water in the step of dispersing in water.

3. A step of coating fibers with the fiber coating agent produced by the method for producing a fiber coating agent according to claim 1 or 2; drying the coated fibers; A method for producing a coated fiber, comprising:

4. Contains nanocellulose and fibers, The surface of the fiber is coated with the nanocellulose. Coated fiber.

5. The coated fiber according to claim 4 , wherein the nanocellulose is derived from sea squirt shells or from green algae.

6. 6. The coated fiber of claim 4 or 5, wherein the tensile strength of the coated fiber is improved by at least 20% over the tensile strength of the fiber.

7. A coated fiber fabric using the coated fiber according to any one of claims 4 to 6.

8. 8. The coated fiber fabric according to claim 7, wherein the maximum temperature difference between the temperature of the coated fiber fabric in a moisture absorption heat generation test and the temperature of an uncoated fiber fabric in a moisture absorption heat generation test is 0.5°C or more.

Images