KR20010105694A - film coated with photochemical active catalyst layer - Google Patents

Abstract

Disclosed are absorbent cores for inclusion in absorbent articles such as diapers, incontinent briefs, training pants, diaper holders and liners, feminine hygiene garments, and the like, designed to provide improved fit and comfort for the wearer while adequately containing body exudates. The absorbent cores are designed to be relatively narrow in the crotch region of the article, even when the core absorbs significant amounts of fluid during use. To achieve this, the absorbent core is designed such that fluid is moved substantially from the crotch region to the front and/or rear regions of the article. The invention particularly relates to an absorbent article comprising an absorbent core wherein the absorbent core has a crotch width when dry and when wet of not more than about 7 cm, and wherein the crotch region of the absorbent core has a capacity of not more than about 40 % of the absorbent core's total absorbent capacity.

Description

Film coated with photochemical active catalyst layer

The present invention relates to a photocatalytically active film (film). More specifically, the present invention relates to a film having a photocatalytic activity by coating a photocatalyst such as titanium dioxide (titanium oxide or titania), zirconium oxide, arsenic oxide, zinc oxide, tin oxide or cerium oxide.

The photocatalyst is a semiconducting metal oxide that absorbs bandgap energy of 3.2 eV or more and 400 nm or less to form electron hole pairs, and the excited holes react with water by strong oxidizing power to produce OH radicals. Will decompose organic matter.

^{M + hυ → M + e -} + h + (1)

MH ₂ O + h ⁺ → M-OH + O (2)

M-OH + h ⁺ → M + OH (3)

The generated energy of the OH radical is equivalent to 120 Kcal / mol and is larger than the various bond energies of the CC bond, CH bond, CN bond, CO bond, OH bond and NH bond of the organic compound, and thus, the action of decomposing such bond Because organic matter can be easily decomposed, it is widely used for the removal and sterilization of contaminants, harmful substances or germs.

In order to take advantage of the strong oxidation of the photocatalyst, a tile having a strong bactericidal effect and discoloration resistance has been manufactured by incorporating titanium dioxide into the tile to give antibacterial properties. There is a case where the management cost is reduced by applying to the lighting such as the street lamp by the automatic purification function by the resolution of titanium dioxide. Photocatalysts can also be applied to air pollution or wastewater treatment. Since the reaction structure is simple and powerful, it can be an innovative technique if efficiency is improved (for titanium oxide photocatalysts, Siemushi, 1998). It can also be used to enhance the surface cleaning effect by using superhydrophilicity due to water adsorption reaction.

Various materials for supporting the photocatalyst have been proposed. The photocatalyst is coated on the surface of a ceramic or inorganic fiber such as glass or tile by solution precipitation and sol-gel method followed by baking or chemical vapor deposition (CVD). There is an example in which paper has been prepared by incorporating a photocatalyst into pulp and having an antifouling effect or an odor removal effect. However, in addition to the above-mentioned minerals, various attempts have been made to apply titanium dioxide to up to 90% of plastics.

As a method of coating the photocatalyst on the substrate, the film can be formed at a relatively low temperature by vacuum treatment by CVD, ion plating, and sputtering. However, such a device requires expensive equipment with a vacuum and it is impossible to form a thin film on a large area substrate or to form a homogeneous thin film on a complex substrate surface.

In a simplified way, a photocatalyst sol made of alkoxide can be prepared to coat the photocatalyst by applying the sol phase by dipping, spin coating or spraying and baking at a temperature of several hundred degrees. The coating by the sol-gel method is generally not satisfactory because a baking temperature of 300 to 400 ° C. is required and the bonding force is due to van der Waals bonding force rather than chemical bonding. Attempts have been made to lower the temperature of baking, but 200 ° C. is a minimum temperature.

More than 90% of the household goods in use today are made of plastic, and there are many substitutions for plastic as structural materials. Therefore, if the photocatalyst can be effectively applied on the plastic can be applied to various fields. It can be applied to an air purifier, a ventilation fan, a fan, a cleaner, a clothes dryer, a dish dryer, a dishwasher, and kitchen waste to prevent pollution, prevent microbial propagation, and remove odors (Patent Publication 1998-087179). However, baking temperatures of 200 ° C correspond most to plastic deformation temperatures. Therefore, the application of this method to plastics is limited.

Titanium dioxide powder was incorporated into the pulp slurry to produce paper, demonstrating the effects of acetaldehyde decomposition and discoloration resistance, but the burst strength of the paper decreased with use time (p120 for titanium oxide photocatalysts, siemus time). , 1998 Japan). By incorporating and molding a photocatalyst powder into a fluororesin powder having strong chemical resistance, a structural exterior material that requires no maintenance has been proposed (Japanese Patent Laid-Open No. 6-365614). Although fluorocarbon resin is stable to photocatalytic activity, it is expensive and photocatalytic activity is inefficient due to the high rate of titanium dioxide being contained in the resin.

There are several problems to be solved in loading photocatalysts in plastics.

a) Photocatalyst should adhere well to the base.

b) not only does the photocatalyst not sink on the substrate so that the photocatalytic activity should not be reduced,

c) the matrix should not deteriorate due to photocatalytic activity.

d) The baking temperature should be below the heat deflection temperature of the plastic film.

The present invention provides a photocatalytic active film having excellent bonding ability between the film and the coating film and excellent photocatalytic activity that is not deteriorated by photocatalytic chemical reaction by coating a protective layer on one surface of a plastic substrate film, and forming a film thereon, and drying the same. It is to provide. In another aspect, the present invention is to produce an economical photocatalytic active film that can be stamped on household goods.

1 is an explanatory diagram of a photocatalytic action

2 is a table of decomposition of cooking oil on a photocatalytic active membrane

3 is a breakdown strength measurement table of the photocatalytic active membrane

By the present invention

1) preparing a plastic base film;

2) laminating and drying a protective layer mainly composed of silicon resin on the film at 1 to 10 μm on the film;

3) applying a catalyst dispersion in which the photocatalyst oxide is dispersed in a silica sol in a molar ratio of silica to 1/10 to 10 at 0.5 to 20 μm on the film of step 2);

4) pre-drying the film of step 3) at a temperature of 100 ° C. or less; And

5) There is provided a method for producing a photocatalytic active film comprising the step of baking the pretreated film in a range where the base film is not deformed at 110 ° C. or higher.

Also by the present invention

1) a paper or plastic base film having a deformation temperature of 110 ° C. or higher;

2) a silicon resin layer laminated on the film with a thickness of silicon resin 1 to 10 μm;

3) a catalyst dispersion layer in which a photocatalyst oxide is dispersed in a molar ratio of silica to 1/10 to 10 in a silica sol coated at 0.5 to 20 μm on the resin layer, and the layer is baked at a temperature of 110 ° C. or higher. And a photocatalytic active film bonded to the silicon resin layer.

The plastic film having a deformation temperature of 110 ° C. or more is a general-purpose plastic, and nylon, acrylic, polyester, polyacetal and copolymer films thereof may be used. Nylon is preferably aromatic nylon 6 or nylon 6.6 copolymer. Acrylic is a polyacrylic acid resin derivative and polyester is preferably polyethylene terephthalate. As the high heat resistant resin film, polyphenylene sulfide, polyphenylene oxide, polyether imide and the like can be used.

Materials used for the adhesive layer include silicon modified resins containing 2-60% by weight of silicon; Or a resin containing 3-60% by weight of polysiloxane. The resin is suitable for strongly bonding the photocatalyst and protecting the carrier from the photocatalyst. When using an acrylic-silicon resin containing less than 2% by weight of silicon and a resin containing less than 3% by weight of polysiloxane, the adhesion of the photocatalyst layer is poor due to the weakening of the adhesive layer by the photocatalyst and is easily peeled off. If a silicon-modified resin containing at least 60% by weight of silicon in the acrylic silicon resin is added, the adhesion between the adhesive layer and the carrier is poor and the wear resistance is bad because of the low adhesive strength of the adhesive layer.

The silicon-modified resin used for the adhesive layer is preferably an acrylic-silicon resin, an epoxy-silicon resin or a polyester-silicon resin. Silicon modified resins can be introduced into the resin by a variety of methods, such as transesterification reactions, graft reactions using silicon polymers or reactive silicon monomers, hydroxylation reactions and block copolymerization. The silicon-modified water obtained by any of the above methods can be used as the adhesive layer resin. Among the silicon modified resins, acrylic, epoxy, and polyester resins are most suitable in terms of carrier and film formation, toughness and adhesion. The resin can be dissolved and used in any form of solvent or emulsion.

Preferred polysiloxanes are hydrolysates of silicon alkoxides having alkoxy having 1 to 5 carbon atoms or products made from such hydrolysates. Polysiloxanes obtained by partially hydrolyzing silicon alkoxidepolysiloxanes containing chlorine can be used. The use of polysiloxanes containing a large amount of chlorine results in impure chlorine ions that corrode the carrier or cause poor adhesion.

Preferred polysiloxane compounds are polycondensates of silicon alkoxides represented by the following formula (1).

Formula (1) SiCl _a (OH) _b R _c (OR ′) _d

Wherein R is alkyl having 1-8 carbons which may be substituted with amino, carboxyl or chlorine or alkyl having 1-8 carbons which may be substituted with 1-8 carbons alkoxy and R 'is alkyl having 1-8 carbons A, b and c are 0, 1 or 2, d is an integer of 2-4 and a + b + c + d = 4.

There are various ways of introducing polysiloxane into the resin. For example, the product of partially hydrolyzed silicon alkoxide is previously mixed with the resin and hydrolyzed with moisture in the air when the adhesive layer is formed. Any method which can mix resin uniformly can be used. Small amounts of acid or base catalysts can be added to vary the rate of hydrolysis of silicon alkoxides. It is preferred to add 3-60% by weight of polysiloxane to the resin to strongly adhere the photocatalyst layer onto the carrier. An amount of 3-40% by weight is particularly preferred for improving alkali resistance. Polysiloxanes can be incorporated into any resin, such as acrylic resins, acrylic-silicon resins, epoxy-silicon resins, polyester-silicon resins, silicon-modified resins, urethane resins, epoxy resins, polyester resins and alkyd resins. Silicon-modified resins comprising acrylic-silicone resins, epoxy-silicon resins, polyester-silicon resins and mixtures of these resins are preferred in view of durability and alkali resistance.

In order to obtain a catalyst dispersion, first, TiO ₂ powder is added to the silica gel in a molar ratio of silica photocatalyst in the range of 1/10 to 10. In order to obtain a uniform thickness, immersing the film wound on the drum in a resin containing the photocatalyst dispersion in a method of coating the mixed photocatalyst dispersion on the film in an appropriate thickness to obtain a uniform thickness is obtained. desirable. Coating and drying may be repeated to obtain a coating layer of desired thickness.

The photocatalyst coated film is pre-dried at a temperature lower than 100 ° C. The prebaked film is baked by silica at a temperature of 110 ° C. or more and 130 ° C. or less. At this time, the baking treatment temperature is very important to select the temperature that the base film is not deformed. In order to prevent deformation of the base film, it is sometimes desirable to compress the film coated with the roll heated to the baking temperature. At this time, in order to prevent the thermal deformation of the base film, the roll of the part contacting the base film may select a temperature lower than the catalyst layer baking temperature.

As a result, the catalyst layer is not only firmly bonded to the substrate by the silicone resin, but titanium oxide is supported on the porous silica, and thus photocatalytic activity is maintained and the substrate is blocked and protected from the photocatalyst by the silicone resin, thereby preventing deterioration of the substrate. And various substrates can be used as the photocatalytically active film.

Hereinafter, the present invention will be described by way of examples. The scope of the present invention is not limited by these examples.

Example 1

5 cm thick 0.02 mm polyester films were prepared as the base films, respectively. Polyethoxy siloxane was applied to the film to a thickness of 5㎛ and dried at room temperature for 10 hours. A 100 nm diameter titanium dioxide powder was mixed and dispersed in a silica sol. The catalyst layer was immersed so that the catalyst layer was applied to a thickness of 5㎛ on the catalyst dispersant was applied, and dried at room temperature for 2 hours and then preliminarily dried at 70 ° C. The laminated film was pressed several times with a hot plate heated to 110 ° C.

Example 2

A photocatalyst coating film was prepared in the same manner as in Example 1 except for mixing the molar ratio of silica: titanium oxide to the silica sol so that the photocatalyst dispersant was 1: 5.

Example 3

5 cm thick 0.03 mm white paper was prepared as a base film, respectively. The acryl modified silicon resin was applied to a thickness of 5 μm and dried at room temperature for 10 hours. Hereinafter, titanium dioxide was supported in the same manner as in Example 1.

Example 4

A photocatalyst coated film was prepared in the same manner as in Example 3, except that a molar ratio of silica: titanium oxide was mixed in the silica sol so that the photocatalyst dispersant was 1: 5.

Comparative Example 1

The film was prepared as a base film with 5 cm-thick 0.02 mm polyester each of width and width which were not processed.

Comparative Example 2

5 cm thick 0.02 mm polyester films were prepared as the base films, respectively. An adhesive mixture in which the titanium dioxide sol of 100 nm diameter was mixed and dispersed on the film was coated to a thickness of 10 μm, and then dried at 70 ° C. after 2 hours of drying at room temperature.

Comparative Example 3

Photocatalyst coated white paper was prepared in the same manner as in Comparative Example 1 except that the white paper was used instead of the polyester film.

Test Example 1

Samples of Examples 1 to 4 and Comparative Examples 1 to 3 were coated with 0.1 mg / cm ² of cooking oil, respectively, and irradiated with 1 mW / cm ² of ultraviolet light at room temperature at 25 ° C. , and the amount of cooking oil decreased per light irradiation time was investigated. In Comparative Example 1, no appreciable amount of cooking oil was found. Compared with Comparative Examples 2 and 3, the amount of reduction in cooking oil of Examples 1 to 4 was noticeable. The results are shown in FIG.

Test Example 2

The tear strength of the base material was measured by performing for a long time under the same conditions as Test Example 1.

In Comparative Example 1, no decrease in burst strength was detected, and in Examples 1 to 4, a slight decrease in burst strength was achieved. In Comparative Examples 2 and 3, the burst strength of the substrate was remarkable.

The results are shown in FIG.

According to the present invention, not only the catalyst layer is firmly bonded to the substrate by the silicone resin but also the titanium oxide is supported on the porous silica to maintain photocatalytic activity and to prevent the substrate from deteriorating because the substrate is blocked and protected from the photocatalyst by the silicone resin. And various substrates can be used as the photocatalytically active film. According to the present invention, it is possible to obtain a film having a high photocatalytic activity without deterioration by ultraviolet rays, and such a film can economically obtain a photocatalytic film which can be used in various ways as a surface heat fusion film for interior and exterior construction and daily necessities. have.

Claims (6)

1) preparing a paper or plastic base film having a deformation temperature of 110 ° C. or higher; 2) laminating and drying a silicon-modified resin or 1 to 10 μm of polysiloxane which is a polycondensate of Formula (1) on the film; 3) applying a catalyst dispersion in which the photocatalyst oxide is dispersed in a silica sol in a molar ratio of silica to 1/10 to 10 at 0.5 to 20 μm on the film of step 2); 4) pre-drying the film of step 3) at a temperature of 100 ° C. or less; And 5) The method of producing a photocatalytic active film comprising the step of baking the pre-treated film 110 ℃ or more in the range that the base film is not deformed. Formula (1) SiCl _a (OH) _b R _c (OR ′) _d Wherein R is alkyl having 1-8 carbons which may be substituted with amino, carboxyl or chlorine or alkyl having 1-8 carbons which may be substituted with 1-8 carbons alkoxy and R 'is alkyl having 1-8 carbons A, b and c are 0, 1 or 2, d is an integer of 2-4 and a + b + c + d = 4. The method according to claim 1, wherein the base film is nylon, acrylic, polyester, polyacetal, copolymers thereof, polyphenylene sulfide, polyphenylene oxide or polyetherimide. The method for producing a photocatalytically active film according to claim 2, wherein the base film is polyester, polyphenylene sulfide, polyphenylene oxide, polyether imide. The method for producing a photocatalytic active film according to claim 1, wherein the polysiloxane is a polysiloxane represented by the following formula (1). The method for producing a photocatalytic active film according to claim 4, wherein the silicon-modified resin is an acrylic-modified silicon resin. 1) paper or plastic base film having a deformation temperature of 110 ° C. or higher; 2) a silicon modified resin layer laminated on the film with a thickness of silicon resin 1 to 10 μm or a polysilonic acid resin layer which is a polycondensate of the following formula (1); 3) a catalyst dispersion layer in which a photocatalyst oxide is dispersed in a molar ratio of silica to 1/10 to 10 in a silica sol coated at 0.5 to 20 μm on the resin layer, and the layer is baked at a temperature of 110 ° C. or higher. And a photocatalytic active film bonded to the silicon resin layer. Formula (1) SiCl _a (OH) _b R _c (OR ′) _d Wherein R is alkyl having 1-8 carbons which may be substituted with amino, carboxyl or chlorine or alkyl having 1-8 carbons which may be substituted with 1-8 carbons alkoxy and R 'is alkyl having 1-8 carbons A, b and c are 0, 1 or 2, d is an integer of 2-4 and a + b + c + d = 4.