WO2008069370A1

WO2008069370A1 - Photocatalyst filter and manufacturing method thereby

Info

Publication number: WO2008069370A1
Application number: PCT/KR2007/001480
Authority: WO
Inventors: Jin Yeong Lim; Cheol Nam; Eui Bung Jeoung; Jae Hyeon Park; Kyong Hwan Lee; Seung Young Lee
Original assignee: Sane Tech Co., Ltd.
Priority date: 2006-12-06
Filing date: 2007-03-27
Publication date: 2008-06-12
Also published as: KR100765825B1

Abstract

This invention relates to a photocatalyst filter using a photocatalyst and a method of manufacturing the same, and more particularly, to a photocatalyst filter, including a bead layer having a plurality of beads bound to each other to form fine pores and a photocatalyst layer formed on the bead layer, and to a method of manufacturing the same.

Description

PHOTOCATALYST FILTER AND MANUFACTURING

METHOD THEREBY

Technical Field

[1] The present invention relates to a photocatalyst filter using a photocatalyst and to a method of manufacturing the same, and more particularly, the present invention relates to a photocatalyst filter, which comprises a bead layer including a plurality of beads bound to each other to form fine pores and a photocatalyst layer formed on the bead layer, and to a method of manufacturing the same. Background Art

[2] Generally, a photochemical reaction using a photocatalyst functions to completely decompose various types of harmful material in the air and in aqueous solutions to thus convert them into harmless material. Further, since the photochemical reaction using the photocatalyst requires only a light source, and thus does not entail problems related to the production of secondary harmful material or the disposal of a filter, the photocatalyst may be permanently used.

[3] Titanium dioxide, which is very useful as the photocatalyst, is a material that is harmless to the human body, and thus is suitable for use in general living goods. Accordingly, thorough research into the treatment of environmental contaminants through a photochemical reaction using a titanium dioxide photocatalyst has been conducted.

[4] In recent years, various attempts to apply the titanium dioxide photocatalyst to the filter of an air purifier have been made, and a photocatalyst filter having increased de- odorization and disinfection effects due to an enlarged surface area thereof has been disclosed in Korean Unexamined Patent Publication No. 10-2003-0088745.

[5] The photocatalyst filter for an air purifier, disclosed in Korean Unexamined Patent

Publication No. 10-2003-0088745, has a honeycombed structure, in which the filter is formed with transparent synthetic resin, coated with a photocatalyst, and then formed in multiple layers, and thus the surface area thereof is maximized, consequently realizing excellent deodorization and disinfection effects. However, since this filter does not filter fine dust in the air, an additional filter member should be provided.

[6] Furthermore, since the above photocatalyst filter has a honeycombed structure, it must be mounted in the air purifier, and thus it is difficult to decrease the size of the air purifier.

Disclosure of Invention

Technical Problem

[7] Therefore, the present invention has been made keeping in mind the above problems encountered in the related art, and an object of the present invention is to provide a photocatalyst filter, which is able to exhibit excellent deodorization and disinfection effects, to filter fine dust, and to serve as part of a housing of an air purifier, and also to provide a method of manufacturing the same. Technical Solution

[8] In order to achieve the above object, the present invention provides a photocatalyst filter, comprising a bead layer including a plurality of beads bound to each other to form fine pores, and a photocatalyst layer formed on the bead layer.

[9] The plurality of beads, constituting the bead layer, preferably has a diameter of

0.5-2.0 D, and the bead layer preferably has a thickness of 3.0-20.0 D.

[10] The bead layer preferably comprises 100 parts by weight of the plurality of beads and 0.8-4.5 parts by weight of a binder including a thermosetting resin and a curing agent.

[11] In addition, the present invention provides a method of manufacturing a photocatalyst filter, comprising steps of:

[12] a) mixing a plurality of beads, coated with a photocatalyst, with a binder including a thermosetting resin and a curing agent; and

[13] b) molding the mixture of step a) to a predetermined shape so that fine pores are formed between the beads, and then performing a curing process.

[14] In addition, the present invention provides a method of manufacturing a photocatalyst filter, comprising steps of:

[15] a) mixing a plurality of beads with a binder including a thermosetting resin and a curing agent;

[16] b) molding the mixture of step a) to a predetermined shape so that fine pores are formed between the beads, and then performing a curing process; and

[17] c) forming a photocatalyst layer on the surface of the cured product of step b).

[18] In the method of the preset invention, step a) is preferably conducted by mixing 100 parts by weight of the plurality of beads, coated with the photocatalyst, with 0.8-4.5 parts by weight of the binder, including the thermosetting resin and the curing agent.

[19] Further, step b) is preferably conducted by molding the mixture of step a) to a thickness of 3.0-20.0 D and then performing a curing process.

[20] Furthermore, step b) is preferably conducted by placing the mixture in the molding space of a mold, compressing the mixture placed in the mold to thus produce a molded product, and then curing the molded product in a heating atmosphere.

[21] Hereinafter, a detailed description will be given of the photocatalyst filter of the present invention and the manufacturing method thereof.

[22] The photocatalyst filter of the present invention comprises a bead layer including a plurality of beads bound to each other to form fine pores, and a photocatalyst layer formed on the bead layer.

[23] The bead layer is obtained by mixing the plurality of beads with a binder and then molding the mixture to form a predetermined shape.

[24] The plurality of beads functions to filter fine dust through fine pores formed by the mutual contact of the beads and also to efficiently circulate air, and the diameter thereof is preferably set to 0.5-2.0 D.

[25] In the case where the diameter of the plurality of beads is less than 0.5 D, the size of the pores formed by mutual contact of the beads is very small, and thus such pores are filled with the binder, undesirably impeding the circulation of air. On the other hand, in the case where the diameter of the beads exceeds 2.0 D, the size of the pores formed by the mutual contact of the beads is large, and thus the circulation of air is efficiently realized, but fine dust may not be effectively filtered, consequently making it impossible to maximally exhibit the filter function.

[26] The binder, which is used to bind the plurality of beads to each other, includes thermosetting resin, such as epoxy resin or phenol resin, and a curing agent, and is added in an amount of 0.8-4.5 parts by weight, based on 100 parts by weight of the plurality of beads.

[27] When the binder is contained in an amount less than 0.8 parts by weight, the beads are weakly bound to each other, undesirably decreasing durability. On the other hand, when the binder is contained in an amount exceeding 4.5 parts by weight, the beads are firmly bound to each other, thus increasing durability, but the pores formed between the beads are filled with the binder, undesirably impeding the circulation of air, making it impossible to maximally exhibit the filter function.

[28] FIG. 1 is a view showing a cylindrical photocatalyst filter, and FIG. 2 is view showing a plate-shaped photocatalyst filter.

[29] The bead layer, obtained by subjecting the plurality of beads and the binder to mixing, molding and curing, has a predetermined shape, including a cylinder, a cone, a polygonal pyramid, such as a triangular pyramid or a quadrangular pyramid, and a polygonal plate, such as a triangular plate or a quadrangular plate, as shown in FIGS. 1 and 2, and the thickness (T) thereof is preferably set to 3.0-20.0 D.

[30] When the bead layer is thinner than 3.0 D, air is efficiently circulated through the pores formed between the beads. However, fine dust may not be effectively filtered, and furthermore, the bead layer may be easily broken by external force due to poor durability. On the other hand, when the bead layer is thicker than 20.0 D, durability and filtration efficiency are superior, but the circulation of air is not realized well and many beads are required, undesirably decreasing productivity.

[31] The photocatalyst layer functions to convert harmful material in the air, introduced into the purifier, into harmless material using UV light applied from a UV lamp. The photocatalyst layer may be formed 1) by subjecting a plurality of beads and a binder to mixing, molding, and curing to thus form a bead layer, which is then coated with a photocatalyst, thus forming a photocatalyst layer, or alternatively, 2) by subjecting beads, coated with a photocatalyst, and a binder to mixing, molding and curing, thus forming a photocatalyst layer.

[32] In this way, the photocatalyst filter of the present invention includes the bead layer having fine pores and the photocatalyst layer formed on the bead layer, and therefore exhibits deodorization and disinfection effects through the reaction with UV light and also manifests filtration effects through fine pores. Particularly, since the photocatalyst layer, which is formed on the bead layer, has an increased contact area with UV light, excellent deodorization and disinfection effects may be realized.

[33] The method of manufacturing the photocatalyst filter of the present invention is fur ther described below.

[34] The method of manufacturing the photocatalyst filter of the present invention includes 1) a method including forming a bead layer using a plurality of beads coated with a photocatalyst, and 2) a method including forming a bead layer, and then forming a photocatalyst layer on the bead layer.

[35] The method 1) for manufacturing the photocatalyst filter of the present invention includes mixing a plurality of beads, coated with a photocatalyst, with a binder, and then subjecting the mixture to molding and curing.

[36] The mixing process is conducted by uniformly mixing a plurality of beads, coated with a photocatalyst, with a binder. As such, it is preferred that 100 parts by weight of the beads and 0.8-4.5 parts by weight of the binder be mixed to thus obtain a mixture.

[37] In the case where the binder is used in an amount less than 0.8 parts by weight, the plurality of beads is weakly bound to each other and thus may be easily broken by external force due to poor durability. On the other hand, in the case where the binder is used in an amount exceeding 4.5 parts by weight, fine spaces, which are formed between the beads, are filled with the binder, undesirably impeding the circulation of air.

[38] The diameter of the plurality of beads coated with the photocatalyst is preferably set to 0.5-2.0 D, in order to effectively filter fine dust and to efficiently circulate air.

[39] Subsequently, the molding and curing processes are conducted by placing the mixture in the molding space of a mold to thus form a molded product having a predetermined shape, which is then cured.

[40] The molding space of the mold is formed to correspond to the cylinder or plate shape of a molded product, and the width of the molding space is set to 3.0-20.0 D so as to obtain a molded product having superior durability and high fine dust filtration efficiency.

[41] The mixture, placed in the molding space of the mold, is preferably compressed using a press, so that the plurality of beads is brought into close contact with each other, without empty spaces.

[42] The molded product thus obtained is cured in a heating atmosphere, thereby completing the photocatalyst filter of the present invention. As such, the curing temperature is determined depending on the type of the curing agent. For example, in the case where an acid anhydride-based curing agent is used, the molded product is cured at 110- 17O⁰C.

[43] Further, in order to remove the binder layer from the surface of the cured product, it is preferred that a process of pyrolyzing the binder be provided.

[44] In the case where the binder layer is formed thickly on the surface of the cured product, deodorization and disinfection functions are not exhibited even if UV light is radiated onto the surface of the cured product. Hence, the binder formed on the surface of the cured product should be pyrolyzed.

[45] Although the pyrolysis temperature varies depending on the types of thermosetting resin and curing agent of the binder, and also on the amounts thereof, it is not particularly limited. For example, in the case where a binder, comprising 100 parts by weight of epoxy resin and 50 parts by weight of an acid anhydride-based curing agent, is used, a pyrolysis temperature is set to 180~230°C.

[46] The method 2) for manufacturing the photocatalyst filter of the present invention includes subjecting a plurality of beads and a binder to mixing, molding, curing, and then coating using a photocatalyst.

[47] The mixing process, the molding process and the curing process of the above method are the same as the mixing process, the molding process and the curing process of the method 1) for manufacturing the photocatalyst filter, with the exception that a plurality of beads which is not coated with a photocatalyst is used, and thus a detailed description thereof is omitted.

[48] The coating process using a photocatalyst is performed by coating the surface of the cured product obtained through molding and curing with the photocatalyst. Examples of the process of coating the cured product with the photocatalyst include, but are not limited to, a process of spraying a photocatalyst suspension on the surface of the cured product, a process of immersing the cured product in a photocatalyst suspension, a process of applying a photocatalyst suspension on the surface of the cured product using a brush, and a process of spraying photocatalyst powder on the wet surface of the cured product.

[49] In the present invention, the photocatalyst filter thus obtained may be widely used for air purifiers. In particular, the photocatalyst filter of the present invention is not mounted in the air purifier but may serve as part of a housing, unlike conventional filters.

[50] Specifically, in the case where the photocatalyst filter has a cylindrical shape, a UV lamp is mounted in the cylindrical photocatalyst filter, an air blower is mounted to the lower portion of the cylindrical photocatalyst filter, and a cover is tightly mounted to the upper portion of the cylindrical photocatalyst filter. External air is introduced into the cylindrical photocatalyst filter through the air blower, and such air is deodorized and disinfected through oxidation with UV light applied from the UV lamp and with the photocatalyst layer of the cylindrical photocatalyst filter, and is then discharged to the outside through fine pores formed in the cylindrical photocatalyst filter. As such, fine dust contained in air is filtered through the fine pores.

[51] Further, the plurality of beads constituting the cylindrical photocatalyst filter may be formed to have various colors, and thus the air purifier may be used as a decorative item.

[52] In this way, in the case where the photocatalyst filter of the present invention is applied to the air purifier, it is advantageous because it may serve as part of the housing, deodorization and disinfection effects may be exhibited using UV light and the photocatalyst, and as well, fine dust may be filtered through fine pores formed in the photocatalyst filter.

[53] On the other hand, in the case where the photocatalyst filter has a plate shape, an air purifier includes a housing having an open front surface, a plate-shaped photocatalyst filter tightly mounted to the front surface of the housing, a UV lamp mounted in the housing, and an air blower for introducing external air into the housing.

[54] In this case, the plate-shaped photocatalyst filter may be provided as part of the housing, and thus, the structure of the air purifier may be simplified, and furthermore, deodorization and disinfection effects and filtration effects of fine dust may be exhibited.

[55] As mentioned above, the photocatalyst filter of the present invention may serve as the outer covering of the air purifier, that is, as part of the housing, therefore making it possible to decrease the size of the air purifier.

Advantageous Effects

[56] According to the present invention, the photocatalyst filter includes a bead layer having fine pores and a photocatalyst layer formed on the bead layer, thereby realizing deodorization and disinfection effects using UV light applied from a UV lamp and also using the photocatalyst layer. As well, fine dust may be filtered through fine pores formed in the bead layer. Furthermore, in the case where the bead layer is formed to have various colors, a function as a decorative item may be provided. [57] The plurality of beads constituting the bead layer has a diameter of 0.5-2.0 D, and the bead layer has a thickness of 3.0-20.0 D, thereby effectively filtering fine dust.

[58] The bead layer includes 100 parts by weight of the plurality of beads and 0.8-4.5 parts by weight of a binder composed of a thermosetting resin and a curing agent, in which the plurality of beads is firmly bound to each other, thus exhibiting superior durability. As well, because fine pores formed between the beads are not filled with the binder, it is possible to efficiently circulate air to thus effectively filter fine dust.

[59] Further, the method of manufacturing the photocatalyst filter of the present invention comprises mixing the plurality of beads, coated with the photocatalyst, with the binder, molding the mixture to a predetermined shape to form fine pores between the beads, and curing the molded product, thereby realizing deodorization and disinfection effects and also enabling the production of a photocatalyst filter that is able to filter fine dust through fine pores using a simple process.

[60] Particularly, the molding and curing processes include placing the mixture in the molding space of a mold, compressing the mixture placed in the mold to thus form the molded product, and curing the molded product in a heating atmosphere. Thereby, the beads are brought into mutual contact and thus bound to each other without empty spaces therebetween, yielding a cured product having fine pores.

[61] Also, a pyrolysis process of pyrolyzing the binder layer formed on the surface of the cured product is further conducted, so that the binder layer formed on the surface of the cured product is pyrolyzed to thus remove it, thereby effectively realizing deodorization and disinfection effects using the photocatalyst layer and UV light.

[62] In addition, the method of the present invention includes mixing the plurality of beads with the binder, molding the mixture to form fine pores between the beads, curing the molded product, and forming the photocatalyst layer on the surface of the cured product. Thereby, the beads are brought into mutual contact and are thus bound to each other without empty spaces therebetween, yielding the cured product having fine pores. Brief Description of the Drawings

[63] FIG. is a view showing a cylindrical photocatalyst filter; and

[64] FIG. 2 is a view showing a plate-shaped photocatalyst filter.

Mode for the Invention

[65] [Example 1]

[66] 100 parts by weight of glass beads having a diameter of 0.5 D and coated with a photocatalyst, and 2.0 parts by weight of a binder were mixed until uniform. As such, the binder was composed of 100 parts by weight of epoxy resin and 50 parts by weight of an acid anhydride-based curing agent. [67] The mixture was placed in a mold in an amount having a volume equal to about 1/2 that of the mold, said mold having a molding space capable of molding a cylindrical photocatalyst filter having a length of 300 D, an outer diameter of 100 D, and an inner diameter of 90 D, after which the mixture placed in the molding space of the mold was compressed using a press. Subsequently, the above placing and compression processes were repeated several times, thus obtaining a cylindrical molded product having a length of 300 D, an outer diameter of 100 D, and an inner diameter of 90 D.

[68] The molded product was cured at 150~170°C, and was then cooled, therefore completing a cylindrical photocatalyst filter of Example 1.

[69]

[70] [Examples 2-4]

[71] In contrast to Example 1, cylindrical photocatalyst filters of Examples 2 to 4 were manufactured using glass beads having a diameter of 1.0 D and coated with a photocatalyst, glass beads having a diameter of 1.5 D and coated with a photocatalyst, and glass beads having a diameter of 2.0 D and coated with a photocatalyst, respectively.

[72]

[73] [Examples 5-7]

[74] In contrast to Example 1, photocatalyst filters of Examples 5 to 7 were manufactured using mixtures obtained by uniformly mixing 100 parts by weight of glass beads coated with a photocatalyst with 0.8 parts by weight, 3.0 parts by weight, and 4.5 parts by weight, respectively, of a binder.

[75]

[76] [Examples 8-10]

[77] A photocatalyst filter of Example 8, having a length of 300 D, an outer diameter of

100 D, and an inner diameter of 97 D, a photocatalyst filter of Example 9, having a length of 300 D, an outer diameter of 100 D, and an inner diameter of 85 D, and a photocatalyst filter of Example 10, having a length of 300 D, an outer diameter of 100 D, and an inner diameter of 80 D, were manufactured, respectively, using molds having molding spaces having widths different from those in Example 1.

[78]

[79] [Example 11]

[80] The cylindrical molded product was cured at 150~170°C, and was then subjected to surface pyrolysis at 180~230°C and then cooling, thus manufacturing a cylindrical photocatalyst filter of Example 10.

[81]

[82] [Example 12]

[83] In contrast to Example 1, using glass beads not coated with the photocatalyst, a cylindrical cured product was formed, immersed in a photocatalyst suspension, and then dried, thus completing a photocatalyst filter of Example 12.

[84] The air volume test of the photocatalyst filters of Examples 1 to 12 was conducted according to Appendix 1 of KSC 9304. [85] The test for evaluating the ability to oxidize organic material of the photocatalyst filter was conducted by disposing an air purifier having the cylindrical photocatalyst filter in a closed space, injecting 500 ppm of acetaldehyde into the closed space, and measuring the concentration of acetaldehyde over time using a gas analyzer to thus determine the time period required to completely oxidize acetaldehyde.

[86] The dust collection test of the photocatalyst filter was conducted according to KSC 9314 (air purifier). [87] The results of the air volume test, the organic material oxidation test, and the dust collection test of the photocatalyst filters of Examples 1 to 12 are shown in Table 1 below.

[88] [Table 1] [89] Test Results of Air Volume, Organic Material Oxidation, and Dust Collection.

Industrial Applicability

[90] As described hereinbefore, the present invention provides a photocatalyst filter, which is able to exhibit excellent deodorization and disinfection effects and is able to filter fine dust, and thus can be widely used for air purifiers.

Claims

[1] A photocatalyst filter, comprising a bead layer including a plurality of beads bound to each other to form fine pores, and a photocatalyst layer formed on the bead layer.

[2] The photocatalyst filter according to claim 1, wherein the plurality of beads, constituting the bead layer, has a diameter of 0.5-2.0 D, and the bead layer has a thickness of 3.0-20.0 D.

[3] The photocatalyst filter according to claim 2, wherein the bead layer comprises

100 parts by weight of the plurality of beads and 0.8-4.5 parts by weight of a binder including a thermosetting resin and a curing agent.

[4] A method of manufacturing a photocatalyst filter, comprising steps of: a) mixing a plurality of beads, coated with a photocatalyst, with a binder including a thermosetting resin and a curing agent; and b) molding the mixture of the step a) to a predetermined shape so that fine pores are formed between the beads, and then performing a curing process.

[5] The method according to claim 4, wherein the step a) is conducted by mixing

100 parts by weight of the plurality of beads, coated with the photocatalyst, with 0.8-4.5 parts by weight of the binder including the thermosetting resin and the curing agent.

[6] The method according to claim 5, wherein the step b) is conducted by molding the mixture of the step a) to a thickness of 3.0-20.0 D and then performing a curing process.

[7] The method according to claim 4, wherein the step b) is conducted by placing the mixture in a molding space of a mold, compressing the mixture placed in the mold to thus produce a molded product, and then curing the molded product in a heating atmosphere.

[8] The method according to claim 5, further comprising pyrolyzing a binder layer formed on a surface of the cured product after the curing process.

[9] A method of manufacturing a photocatalyst filter, comprising steps of: a) mixing a plurality of beads with a binder including a thermosetting resin and a curing agent; b) molding the mixture of the step a) to a predetermined shape so that fine pores are formed between the beads, and then performing a curing process; and c) forming a photocatalyst layer on a surface of the cured product of the step b).

[10] The method according to claim 8, wherein the step a) is conducted by mixing

100 parts by weight of the plurality of beads with 0.8-4.5 parts by weight of the binder including the thermosetting resin and the curing agent.

[11] The method according to claim 10, wherein the step b) is conducted by molding the mixture of the step a) to a thickness of 3.0-20.0 D and then performing a curing process.

[12] The method according to claim 9, wherein the step b) is conducted by placing the mixture in a molding space of a mold, compressing the mixture placed in the mold to thus produce a molded product, and then curing the molded product in a heating atmosphere.