JP2007136342A - Fiber fabric exhibiting photocatalytic function to visible light and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber fabric exhibiting a photocatalytic function to visible light, in which a fiber or a binder is hardly decomposed even in the sunlight having strong ultraviolet light and which exhibits a deodorizing function, an antibacterial function, a sebaceous scurf decomposing function, etc. even in a fluorescent light rich in visible light and poor in ultraviolet light and has satisfactory photocatalytic activity and to provide a method for manufacturing the fiber fabric exhibiting the photocatalytic function to visible light. <P>SOLUTION: The fiber fabric exhibiting the photocatalytic function to visible light is characterized in that zinc oxide fine particles, the average secondary particle size of which is ≤1 μm when the cumulative frequency is 90%, are fixed to the fiber fabric by the binder. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a visible light type photocatalytic functional fiber fabric that can exhibit photocatalytic activity even under a light source such as a fluorescent lamp that has a large amount of visible light and a small amount of ultraviolet light, and a method for producing the same.

  In recent years, functional fiber products that can exhibit a deodorizing function, an antibacterial function, a protein soil degradation function such as sebum (hereinafter referred to as sebum soil degradation function), etc. by applying fine particles having photocatalytic activity to a fiber fabric have been proposed. Has been. This functional fiber product utilizes the decomposition of malodorous substances and harmful substances present around the fiber product by the strong oxidizing action of OH radicals generated by the action of ultraviolet rays on the photocatalyst.

  However, when fine particles having photocatalytic activity are fixed to the fiber fabric, the first problem that the fixed fiber itself and the binder used for fixing are decomposed by the photocatalytic activity occurs. That is, when the fibers and the binder are decomposed, the functional durability of the functional fibers is not maintained, and a bad odor is generated by the decomposition gas.

  Moreover, textile products are generally washed and used continuously. After washing, textile products are often dried indoors under fluorescent lamps as well as dried under strong sunlight. In recent years, there has been a great demand for indoor drying, and in this case, a bad odor may be generated in the textile product. In this case, the fluorescent lamp light has less ultraviolet light than sunlight, and the photocatalytic activity is not fully exhibited, so that a sufficient deodorizing function, antibacterial function, sebum dirt decomposition function, etc. cannot be obtained. A problem occurs.

As a method for simultaneously solving these two problems, a functional fiber fabric described in Patent Document 1 has been proposed. This functional fiber fabric is characterized in that a visible light photocatalyst is fixed to the fiber fabric with a cellulose binder and / or a polysaccharide binder.
JP 2004-137611 A

  By the way, in the functional fiber cloth described above, a specific photocatalyst having photocatalytic activity by visible light by introducing nitrogen into titanium dioxide is applied to the fiber cloth with a specific binder called a cellulose binder and / or a polysaccharide binder. It is fixed.

  That is, the specific photocatalyst has a strong photocatalytic activity not only under visible light but also under ultraviolet light as in the case of conventional photocatalysts. Therefore, even in this case, the specific binder is required so that the fibers and the binder are not decomposed.

  Moreover, the binder which fixes a photocatalyst to a fiber needs to select an optimal binder according to the said fiber from points, such as durability of photocatalytic activity, and the texture of a fiber fabric.

  However, limiting to the specific binder as described above causes a problem that the photocatalyst cannot be widely used for arbitrary fibers.

  In view of the above, the present invention addresses the above-described problems, and makes it difficult for fibers and binders to be decomposed even under sunlight with a strong ultraviolet ray, and is based on a light source such as a fluorescent lamp that has a large amount of visible light and a low ultraviolet ray. However, it aims at providing the visible light type photocatalyst functional fiber fabric which has sufficient photocatalytic activity which can exhibit the deodorizing function, antibacterial function, sebum dirt decomposition function, etc. of a fiber fabric, and its manufacturing method.

  In solving the above-mentioned problem, according to the visible light type photocatalytic functional fiber fabric according to the present invention, the zinc oxide fine particles having a cumulative 90% average secondary particle diameter of 1 μm or less are added to the fiber fabric. It is fixed with a binder.

  According to this, deodorizing function, antibacterial function, sebum dirt of fiber fabric even under fluorescent light with high visible light and low ultraviolet light, which makes fiber and binder difficult to decompose even under strong ultraviolet light. Sufficient photocatalytic activity capable of exhibiting a decomposition function and the like can be exhibited.

  Here, in the present invention, as described in claim 2, the primary particle diameter of the zinc oxide fine particles according to claim 1 may be within a range of 5 nm to 60 nm.

  In the method for producing a visible light photocatalytic functional fiber fabric according to the present invention, according to the third aspect, the 90% cumulative average secondary particle diameter of the zinc oxide fine particles is 1 μm or less. A treatment liquid formed by mixing an aqueous dispersion and an aqueous dispersion of a binder is applied to the fiber fabric to produce a visible light photocatalytic functional fiber fabric.

  As a result, it is possible to produce a visible light photocatalytic functional fiber fabric that can achieve the function and effect of the first aspect of the invention. In addition, by manufacturing the visible light type photocatalytic functional fiber fabric in this way, an optimum binder for fixing the photocatalyst to the fiber fabric can be arbitrarily selected according to the fiber.

  Here, as described in claim 4, in the present invention, the primary particle diameter of the zinc oxide fine particles according to claim 3 may be within a range of 5 nm to 60 nm.

  Hereinafter, an embodiment of a visible light type photocatalytic functional fiber fabric according to the present invention will be described. In the present invention, zinc oxide fine particles which are visible light type photocatalysts are fixed to the fiber fabric.

  The fiber used for the fiber fabric is not particularly limited, and may be generally used as clothing or industrial material. For example, synthetic fibers such as polyester, nylon and acrylic, semi-synthetic fibers such as acetate, natural cellulosic fibers such as cotton and hemp, regenerated cellulosic fibers such as rayon, cupra, polynosic or tencel, protein fibers such as wool and silk and so on.

  These fibers may be used singly or as a mixture of two or more kinds of fibers such as mixed spinning, mixed fiber, union knitting, union knitting, etc. at an arbitrary ratio. Furthermore, the fiber fabric of the present invention may have any form such as a knitted fabric, a woven fabric, and a nonwoven fabric made of the above-described fibers.

  In the present invention, the photocatalyst refers to a substance that decomposes an organic substance using ultraviolet rays such as sunlight and exhibits photocatalytic activity such as a deodorizing function, an antibacterial function, and an antifouling function. In general, semiconductor materials are used for these materials, and in particular, titanium dioxide is widely used.

  In the present invention, the visible light type photocatalyst refers to a substance that exhibits the above photocatalytic activity not only by ultraviolet rays but also by visible light. This material includes a material in which another element such as nitrogen is introduced into titanium dioxide.

  Any of these conventional ultraviolet photocatalysts and visible light photocatalysts exhibit strong photocatalytic activity under ultraviolet light. For this reason, the fiber or binder on which the photocatalyst is fixed is an organic substance and is decomposed. Therefore, any binder does not have durability, or generates a bad odor by the decomposition gas.

  Therefore, as a result of earnest research, the present inventor has made use of zinc oxide fine particles having a specific particle size as a visible light type photocatalyst, so that fibers and binders are not decomposed even under ultraviolet light, and can be arbitrarily selected. It has been found that fibers and arbitrary binders can be used, and that photocatalytic activities such as a deodorizing function, an antibacterial function, and a sebum soil decomposing function can be exhibited even under visible light.

  Here, zinc oxide used in the present invention is a kind of semiconductor, and its photocatalytic activity under ultraviolet rays is known. However, under ultraviolet light, its photocatalytic activity is lower than that of titanium dioxide, and generally it is not used as a photocatalyst.

  The present inventor investigated the photocatalytic activity of zinc oxide fine particles having a specific particle diameter, and exhibited photocatalytic activity such as a deodorizing function, an antibacterial function, and a sebum soil degrading function even under a fluorescent lamp with a large amount of visible light and a small amount of ultraviolet light. It has been fully demonstrated and exhibits photocatalytic activity under ultraviolet rays such as sunlight, but has found that the activity is not strong until the fibers and the binder are decomposed.

  That is, in the visible light type photocatalytic functional fiber fabric according to the present invention, the zinc oxide fine particles having a 90% cumulative average secondary particle diameter of 1 μm or less are fixed to the fiber fabric with a binder, thereby solving the problem of the present invention. Can be achieved.

  In the present invention, zinc oxide is present in the form of secondary particles aggregated on the fiber. This is applied as a dispersed treatment liquid when the primary particles of zinc oxide ultrafine particles are applied to the fibers. In the dispersion, zinc oxide ultrafine particles are present in an aggregated state, forming secondary particles and stably dispersing. The secondary particles are applied and fixed on the fiber in the form of secondary particles.

  The zinc oxide fine particles fixed to the fiber are in the form of secondary particles in which primary particles are aggregated, and the average secondary particle size of 90% cumulative is 1 μm or less. Since the secondary particles are agglomerated particles, they have a certain range of particle size distribution. Specifically, it is preferable to show a particle size distribution within a range of 0.02 μm to 1.2 μm. In this case, it is preferable that an average secondary particle diameter of 50% is 0.1 μm or less.

  Here, the particle diameter of the zinc oxide secondary particles in the dispersion can be measured by various measuring methods. For example, it can be measured by a dynamic light scattering particle size distribution measuring apparatus. Examples of the dynamic light scattering particle size distribution measuring apparatus include MICROTRAC UPA (model: 9340-UPA150) manufactured by Nikkiso Co., Ltd.

  The primary particles of zinc oxide used in the present invention preferably have a particle size within a range of 5 nm to 60 nm. More preferably, it is within the range of 10 nm to 30 nm.

  When the particle diameter of the primary particles is small, the specific surface area of zinc oxide as a photocatalyst is increased. Even if agglomerated into secondary particles, a large portion of the surface area of the primary particles appears to work.

  Thus, zinc oxide, which has conventionally been considered to have a small photocatalytic activity, can have a sufficient photocatalytic activity that can exhibit the deodorizing function, antibacterial function, sebum soil decomposing function, and the like of the fiber fabric.

  In addition, even with this particle size, the characteristic that fibers and binders are not easily decomposed under sunlight with strong ultraviolet rays is maintained.

  On the other hand, the binder used in the present invention is not particularly limited, but is selected from the viewpoints of adhesion and texture between zinc oxide and fibers. In general, acrylic resin, fluorine resin, silicone resin, polyester resin, nylon resin, urethane resin, or the like is used. From these viewpoints, the optimum binder of the fiber is arbitrarily selected in consideration of washing durability and texture from the viewpoint of adhesion to the zinc oxide to be fixed and adhesion to the fiber to be fixed.

  Next, a method for producing a visible light type photocatalytic functional fiber fabric will be specifically described. A dispersion of the zinc oxide fine particles is prepared. This dispersion may be an aqueous dispersion or an organic solvent dispersion. For normal fiber processing, an aqueous dispersion is preferred.

  Specifically, zinc oxide ultrafine particles having a primary particle diameter in the range of 5 nm to 60 nm are dispersed in water using a dispersant. As the dispersant, various surfactants that are usually used can be used. Although the active ingredient of zinc oxide in the dispersion can be arbitrarily adjusted, for example, it is usually within the range of 10 wt% to 40 wt%. The zinc oxide fine particles in the aqueous dispersion are stably dispersed in water as aggregated secondary particles.

  On the other hand, the aqueous dispersion of the binder is also obtained by emulsifying and dispersing the above-described various resins in water using a dispersant. This also usually has a solid content in the range of 10% to 40% by weight, for example.

  The binder aqueous dispersion is mixed with the zinc oxide aqueous dispersion, and the concentration of each component is arbitrarily adjusted by dilution with water. A mixed liquid of the above zinc oxide aqueous dispersion and binder aqueous dispersion is used as the treatment liquid.

  If necessary, a fiber processing aid such as a binder crosslinking agent, a catalyst, a fiber softening agent, or a dye fixing agent may be mixed in the treatment liquid.

  The actual processing of the fiber fabric will be described. The fiber fabric to be processed is pretreated in advance by a conventional method such as scouring and bleaching. In the case of general clothing, the processing of the present invention can be performed after dyeing.

  First, the fiber fabric is impregnated with the aqueous treatment liquid. The impregnation may be performed by any known method such as a pad method, a spray method, or a coating method.

  The greater the amount of zinc oxide fine particles applied to the fiber fabric, the greater the photocatalytic activity. Actually, however, the active ingredient as zinc oxide is in the range of 0.1% to 3.0% by weight with respect to the fiber weight. Within the range of 0.1 wt% to 1.0 wt%. When the amount of zinc oxide is within the range of 0.1% to 3.0% by weight, sufficient deodorizing function and antibacterial function can be exhibited even under a fluorescent lamp, and the fiber fabric maintains a good texture. However, washing durability can be obtained.

  After the impregnation, the fiber fabric is dried and heat-treated as necessary. The conditions for drying and heat treatment are appropriately selected, but are usually within the range of 100 ° C to 180 ° C, preferably within the range of 100 ° C to 160 ° C. The drying time is appropriately selected depending on the temperature, but is usually within a range of 10 seconds to 5 minutes, and preferably within a range of about 30 seconds to 3 minutes.

  The fiber fabric is dried or used after drying or after heat treatment, as it is, or after washing with water as necessary.

  As a result, the fiber fabric processed as described above is difficult to disassemble the fiber and binder even under sunlight with strong ultraviolet rays, and even under a fluorescent lamp with high visible light and low ultraviolet rays, A visible light photocatalytic functional fiber fabric having sufficient photocatalytic activity capable of exhibiting a deodorizing function, an antibacterial function, a sebum soil decomposition function, and the like can be obtained. This makes it possible to arbitrarily select an optimum binder for fixing the photocatalyst to the fiber fabric depending on the fiber.

  Hereinafter, in the present embodiment, the following examples and comparative examples were prepared and evaluated.

Example 1:
In this embodiment, zinc oxide fine particles are fixed to a cotton fabric with an acrylic binder.

  Zinc oxide ultrafine particles having a primary particle diameter in the range of 10 nm to 30 nm were dispersed in water using an anionic emulsifier. The solid content of zinc oxide in the aqueous zinc oxide dispersion was 30% by weight. The average secondary particle diameter of 90% cumulative of the zinc oxide aqueous dispersion was 0.8 μm, and the average secondary particle diameter of 50% cumulative was 0.08 μm.

  Mix 2% by weight of the above zinc oxide aqueous dispersion and 2% by weight of a commercially available acrylic resin aqueous dispersion (Toyo Ink Co., Ltd. Talkrill 0-125; solid content 30% by weight), and prepare a treatment liquid by diluting with water. did.

  The treatment solution was dipped and squeezed by a pad method on 100% cotton scoured and bleached by a normal method, and applied with a pickup of 60% based on the weight of the test fabric.

  After application of the treatment liquid, the test cloth was dried at 120 ° C. for 90 seconds. Subsequently, heat treatment was performed at 150 ° C. for 90 seconds to obtain a test cloth of Example 1.

Comparative Example 1:
In this comparative example, visible light type titanium dioxide fine particles are fixed to the same cotton fabric as in Example 1 with the same acrylic binder as in Example 1 above.

  Nitrogen-introduced titanium dioxide ultrafine particles having a primary particle diameter in the range of 10 nm to 20 nm were dispersed in water using an anionic emulsifier. The zinc oxide solid content in the zinc oxide aqueous dispersion was 10% by weight. The 90% cumulative average secondary particle size of the zinc oxide aqueous dispersion was 0.6 μm, and the 50% cumulative secondary particle size was 0.3 μm.

  6% by weight of the above zinc oxide aqueous dispersion and 2% by weight of a commercially available acrylic resin aqueous dispersion (Toyo Ink Co., Ltd. Tokuril 0-125; solid content 30% by weight) are mixed and diluted with water to obtain a treatment solution. Got ready. The treatment method was performed in the same manner as in Example 1 to obtain a test cloth of Comparative Example 1.

Comparative Example 2:
In this comparative example, ultraviolet-type titanium dioxide fine particles are fixed to the same cotton fabric as in Example 1 with the same acrylic binder as in Example 1 above.

  Commercially available anatase-type titanium dioxide ultrafine particles were dispersed in water using an anionic emulsifier. The zinc oxide solid content in the zinc oxide aqueous dispersion was 10% by weight.

  6% by weight of the above zinc oxide aqueous dispersion and 2% by weight of a commercially available acrylic resin aqueous dispersion (Toyo Ink Co., Ltd. Tokuryl 0-125; solid content 30% by weight) are mixed and diluted with water to obtain a treatment solution. Got ready. The treatment method was performed in the same manner as in Example 1 to obtain a test cloth of Comparative Example 2.

  About each Example and comparative example produced as mentioned above, it evaluated about the characteristic. In this evaluation, photocatalytic activity under visible light and ultraviolet light was evaluated as an evaluation item.

The photocatalytic activity was performed by the following method. Unprocessed cloth and each test cloth of Examples and Comparative Examples are cut into 10 cm × 5 cm, a methylene blue 0.03 g / L aqueous solution is applied, and visible light or ultraviolet light is irradiated. Irradiation with visible light was performed at 8000 LX for 4 hours under a fluorescent lamp. The ultraviolet irradiation was performed for 2 hours under a black light at an ultraviolet intensity of 2000 μW / cm ² . The photocatalytic activity is judged by decoloring the blue color of the methylene blue.

  The color of methylene blue of the test cloth after irradiation was compared to evaluate the photocatalytic activity. The evaluation criteria were evaluated in four stages: very strong photocatalytic activity (☆), good photocatalytic activity (◯), weak photocatalytic activity (Δ), and no photocatalytic activity (×).

  The degradation of the fiber and binder was evaluated based on the photocatalytic activity washing durability. That is, the test cloth after light irradiation was washed and evaluated by judging the degree of decrease in photocatalytic activity after repeating the light irradiation and washing cycle 20 times. Washing was done by home washing in accordance with JIS L 0217 method 103.

  Moreover, about these test cloths, the deodorizing function, the antibacterial function, and the sebum dirt decomposition function were confirmed. As a result, it was confirmed that the above evaluation criteria (◯) have sufficient functionality.

  According to these evaluations, the evaluation results shown in Table 1 below were obtained.

  According to Table 1, Example 1 has good photocatalytic activity under both visible light and ultraviolet light. Also, good photocatalytic activity is maintained even after irradiation washing.

  In contrast, Comparative Example 1 has good photocatalytic activity under visible light, but is too strong under ultraviolet light, and cannot maintain photocatalytic activity after washing with ultraviolet light. .

  On the other hand, Comparative Example 2 cannot exhibit photocatalytic activity under visible light. Further, the photocatalytic activity is too strong under ultraviolet rays, and the photocatalytic activity cannot be maintained after washing with ultraviolet rays.

Claims (4)

  A visible light type photocatalytic functional fiber fabric obtained by fixing zinc oxide fine particles having a cumulative 90% average secondary particle diameter of 1 μm or less to a fiber fabric with a binder.   2. The visible light photocatalytic functional fiber fabric according to claim 1, wherein a primary particle diameter of the zinc oxide fine particles is within a range of 5 nm to 60 nm.   Visible light type produced by applying a treatment liquid obtained by mixing an aqueous dispersion of zinc oxide fine particles having a cumulative 90% average secondary particle diameter of 1 μm or less and an aqueous dispersion of a binder to a fiber fabric. A method for producing a photocatalytic functional fiber fabric. 4. The method for producing a visible light photocatalytic functional fiber fabric according to claim 3, wherein a primary particle diameter of the zinc oxide fine particles is within a range of 5 nm to 60 nm.