U.S. patent application number 09/475150 was filed with the patent office on 2002-01-17 for titanium oxide particle-coated interior member or indoor equipment.
Invention is credited to NAKAMURA, HIDENORI, OHMORI, MASAHIRO.
Application Number | 20020006866 09/475150 |
Document ID | / |
Family ID | 27338694 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020006866 |
Kind Code |
A1 |
OHMORI, MASAHIRO ; et
al. |
January 17, 2002 |
TITANIUM OXIDE PARTICLE-COATED INTERIOR MEMBER OR INDOOR
EQUIPMENT
Abstract
An interior member or indoor equipment provided on the surface
with titanium oxide particles capable of excellent photocatalytic
activity even by irradiation of a weak ultraviolet ray present in
an interior room or the like. An interior member or indoor
equipment with titanium oxide particles containing brookite-type
crystal present on the surface thereof. The titanium oxide
particles may also be bonded to the surface using an adhesive. The
interior member or indoor equipment exhibits a photocatalytic
function upon irradiation of a weak ultraviolet ray having
irradiation energy of from 0.001 to 0.2 mW/cm.sup.2 at 365 nm.
Inventors: |
OHMORI, MASAHIRO; (CHIBA,
JP) ; NAKAMURA, HIDENORI; (CHIBA, JP) |
Correspondence
Address: |
SUGHRUE MION ZINN MACPEAK & SEAS PLLC
2100 PENNSYLVANIA AVE NW
WASHINGTON
DC
200373213
|
Family ID: |
27338694 |
Appl. No.: |
09/475150 |
Filed: |
December 30, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60115149 |
Jan 7, 1999 |
|
|
|
Current U.S.
Class: |
502/350 ;
422/184.1; 423/610 |
Current CPC
Class: |
B01J 35/002 20130101;
E04F 11/00 20130101; F24F 8/167 20210101; B01J 35/004 20130101;
E04F 13/00 20130101; C01P 2006/60 20130101; E04F 19/00 20130101;
A47G 33/02 20130101 |
Class at
Publication: |
502/350 ;
423/610; 588/227; 422/184.1 |
International
Class: |
C01G 023/047; B01J
023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 26, 1999 |
JP |
HEI.11-304603 |
Claims
What is claimed is:
1. An interior member or indoor equipment with titanium oxide
particles containing a brookite-type crystal present on the surface
thereof.
2. An interior member or indoor equipment with titanium oxide
particles containing brookite-type crystal adhered on the surface
thereof using an adhesive.
3. The interior member or indoor equipment as claimed in claim 1,
herein the titanium oxide particle has a photocatalytic function
upon irradiation of an ultraviolet ray having an irradiation energy
of from 0.001 to 0.2 mW/cm.sup.2 at a wavelength of 365 nm.
4. The interior member or indoor equipment as claimed in claim 2,
wherein the titanium oxide particle has a photocatalytic function
upon irradiation of an ultraviolet ray having an irradiation energy
of from 0.001 to 0.2 mW/cm.sup.2 at a wavelength of 365 nm.
5. A method of using titanium oxide particles containing
brookite-type crystal consisting irradiating the particles under
the conditions of an ultraviolet ray having an irradiation energy
of from 0.001 to 0.2 mW/cm.sup.2 at a wavelength of 365 nm.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is an application filed under 35 U.S.C.
.sctn.111(a) claiming benefit pursuant to 35 U.S.C. .sctn.119(e)(i)
of the filing date of Provisional Application 60/115,149 filed Jan.
7, 1999 pursuant to 35 U.S.C. .sctn.111(b).
FIELD OF THE INVENTION
[0002] The present invention relates to an interior member or
indoor equipment using a titanium oxide particle as a
photocatalyst. More specifically, the present invention enables an
organic material or nitrogen oxide adhering to the surface of an
interior member or indoor equipment to be decomposed by the
irradiation of a weak ultraviolet ray.
BACKGROUND OF THE INVENTION
[0003] Photocatalysis is a reaction of decomposing an organic
material or nitrogen oxide present in air or water using light
energy in the presence of a photocatalyst. Thus, photocatalysis is
a technique which uses an ultraviolet ray present in the light
emitted from sunlight or an interior room illuminator such as a
fluorescent lamp and an incandescent lamp, and studies thereon are
being made broadly, for example, on the application to
architectural materials or the cleaning of water or air.
[0004] As the photocatalyst, zinc oxide, cadmium selenide, gallium
arsenide and the like are known but titanium dioxide (hereinafter
referred to as "titanium oxide") is usually used. Titanium oxide is
known to assume three kinds of crystal structures, and in any
structure, a distorted octahedron formed by the 6-coordination of
oxygen atoms to titanium atom is fundamental. The three kinds of
crystal structures are a tetragonal anatase type for low
temperature, a rutile type for high temperature and a rhombic
brookite type for a temperature between those two types. Among
these, anatase titanium oxide is considered to be most excellent as
a photocatalyst and a large number of studies have heretofore been
made thereon.
[0005] It is known that the decomposing action of titanium oxide on
contamination caused by adhesion of an organic material or on the
generation of mold is generally accelerated by the action of an
ultraviolet ray present in sunlight (see, Unexamined Re-Published
International Patent Application WO96-29375). The mechanism in the
decomposing action of titanium oxide is not yet fully understood,
however, the decomposition presently is considered to proceed as
follows.
[0006] When titanium oxide absorbs an ultraviolet ray, two kinds of
electric charges (carriers) of an electron and a hole are generated
inside and the hole is induced on the surface thereof. This hole
acts with water on the particle surface to generate an OH radical
having a strong oxidizing power on the surface of the particle and
the pollutant positioned on the particle surface, such as nitrogen
oxide, is decomposed by the OH radical into carbon dioxide gas,
water or a low molecular weight material. These decomposition
products accumulate on the particle surface and are washed out by
rain or the like. As a result, the photocatalytic action of the
particle is regenerated. Thus, the photocatalytic function of
titanium oxide can be continuously maintained. (See, Akira
Fukushima, Kazuhito Hashimoto and Toshiya Watanabe, Titanium Oxide
Photocatalysis Fundamentals and Applications, BKC Inc.,
(1998)).
SUMMARY OF THE INVENTION
[0007] The present inventors have found that titanium oxide
particles containing a brookite-type crystal exhibit a strong
photocatalytic effect even under a weak ultraviolet ray. The
present invention has been accomplished based on this finding.
[0008] An anatase titanium oxide as a photocatalyst has been mainly
used. Irradiation energy of at least 0.005 mW/cm.sup.2 at a
wavelength of 365 nm is needed to exhibit the function of a
photocatalyst. Therefore anatase titanium oxide as a photocatalyst
has been only adopted on sunshiny areas such as the windows side of
an indoor place or in an outdoor place. Brookite titanium oxide
used in the present invention exhibits its photocatalytic function
under the condition of a weak ultraviolet ray having an irradiation
energy of, for example, 0.001 mW/cm.sup.2 and under the conditions
of light in indoor places.
[0009] The present inventors have thought that since the
photocatalytic property of a titanium oxide particle is influenced
by the OH radical concentration on the surface thereof or the like,
selection of the crystal structure, surface shape or particle size
of titanium oxide and control of the shape are matters of
importance.
[0010] In other words, the generation of OH radicals is governed by
the generation density of holes and the life thereof in the
above-described mechanism and the generation density and life of a
hole is governed by the band gap thereof. Therefore, the
photo-functional property of titanium oxide is considered to be
dependent on the crystal system. It is well known that a
rutile-type crystal has a band gap of 3.0 eV and an anatase-type
crystal has a band gap of 3.2 eV.
[0011] Furthermore, the OH radical is generated by the reaction of
a hole with water, accordingly, the hole potential (corresponding
to the potential of an electric charge depletion layer in the
valence band) on the surface of titanium oxide plays an important
factor. This potential is governed by the band system in the
crystal structure, therefore, also in this point, the
photo-functional property of titanium oxide is inferred to be
dependent on the crystal system.
[0012] However, in the case of decomposing organic material or the
like adsorbed, for example, on an interior member by letting
titanium oxide be present on the surface of an interior member or
indoor equipment in a room, a tunnel, a car, a plane or a ship, the
ultraviolet ray which can be used is a weak ray emitted from an
interior room illuminator and the like. Accordingly, unless a
specific ultraviolet ray source such as a strong ultraviolet ray
lamp is installed, sufficiently high percentage decomposition
cannot be attained.
[0013] The present invention has been made under these
circumstances and a primary object of the present invention is to
obtain an interior member or indoor equipment capable of
decomposing an organic material or nitrogen oxide adsorbed on wall
paper, floor member or gauges, with the irradiation of a weak
ultraviolet ray.
[0014] Another object of the present invention is to provide an
interior member or indoor equipment where titanium oxide particles
containing a brookite-type crystal are present on the surface
thereon.
[0015] Still another object of the present invention is to provide
a method of using titanium oxide particles containing a
brookite-type crystal under the condition of irradiation with an
ultraviolet ray having irradiation energy of from 0.001 to 0.2
mW/cm.sup.2 at a wavelength of 365 nm.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The titanium oxide particles for use in the present
invention contain brookite-type crystal. The titanium oxide
particle is not particularly limited as long as brookite titanium
oxide particle is present. The brookite titanium oxide particle may
be used alone or a rutile or anatase titanium oxide particle may
also be present. In the case of a rutile or anatase titanium oxide
particle is present, the ratio of the brookite titanium oxide
particle in the titanium oxide particles is not particularly
limited but it is usually from 1 to 100 wt %, preferably from 10 to
100 wt %, more preferably from 50 to 100 wt %. This is because the
brookite titanium oxide is superior in photocatalytic activity to
rutile or anatase titanium oxide.
[0017] The titanium oxide particles containing a brookite-type
crystal may be produced by a vapor-phase production process where
anatase titanium oxide particles are heat-treated to obtain
titanium oxide particles containing a brookite-type crystal, or by
a liquid-phase production process where a solution of a titanium
compound such as titanium tetrachloride, titanium trichloride,
titanium alkoxide or titanium sulfate is neutralized or hydrolyzed
to obtain a titanium oxide sol having dispersed therein titanium
oxide particles.
[0018] The production process is not particularly limited as far as
titanium oxide particles containing a brookite-type crystal can be
obtained. However, taking account of the photocatalytic activity
and manageability of the material obtained and in the case of
forming a titanium oxide thin film, transparency and adhesion, a
production process previously found by the present inventors
(Japanese Patent Application Nos. 9-231172 and 10-132195) is
preferred, where titanium tetrachloride is added to hot water at
from 75 to 100.degree. C. and then hydrolyzed at a temperature of
from 75.degree. C. to the boiling point of the solution while
controlling the chloride ion concentration. Thereby titanium oxide
particles containing brookite-type crystal are obtained as a
titanium oxide sol.
[0019] The titanium oxide particles containing brookite-type
crystal are not particularly limited in terms of the size thereof
but usually have an average particle size of from 0.005 to 0.1
.mu.m. If the average particle size exceeds 0.1 .mu.m, the titanium
oxide particles are reduced not only in photocatalytic activity but
also in transparency. Therefore, when such titanium oxide particles
are present on the surface of an interior member or the like, the
color of the titanium oxide adversely affects the color of the
interior member or the like. If the average particle size is less
than 0.005 .mu.m, the titanium oxide particle is difficult to
handle during production thereof. The titanium oxide particle
usually has a specific surface area of 20 m.sup.2/g or more.
[0020] The thus-obtained titanium oxide particles containing a
brookite-type crystal are allowed to be present on the surface of
an interior member or indoor equipment by a method of coating a sol
or solution of titanium oxide particles containing brookite-type
crystal on an interior member substrate and thereafter drying or
heat treating it to bond the particles to the surface of the
interior member substrate or the like, or by a method of mixing
titanium oxide particles containing brookite-type crystal with a
coating material or the like and coating it on an interior member
substrate, followed by drying or heat treatment. The titanium oxide
particles containing brookite-type crystal may also be fixed on the
interior member substrate or the like using, for example, an
adhesive.
[0021] The method of coating a sol or solution of titanium oxide
particles containing a brookite-type crystal on an interior member
substrate is not particularly limited and any known method such as
spin coating, flow coating, dip coating, spray coating, bar
coating, roller coating or brush coating may be used. In the case
of coating a titanium oxide sol, the amount coated is usually from
0.01 to 0.2 mm in terms of the thickness of the film coated.
[0022] In the case where a sol or solution of titanium oxide
particles containing brookite-type crystal is coated on an interior
substrate and thereafter dried or heat treated to bond the
particles to the surface of the interior member substrate or the
like, an adhesive may be added to the titanium oxide sol or
solution. The adhesive is used to increase the adhesion strength
between the titanium oxide particle and the interior member
substrate. Although the adhesive is not particularly limited so far
as it has a photocatalysis resistance, an oxide such as silicon
oxide, aluminum oxide, zirconium oxide, calcium oxide and magnesium
oxide, or an alkoxide as a precursor of these oxides is usually
used.
[0023] These adhesives may be used individually or as a combination
of two or more thereof. In the case of using a combination of
adhesives, the mixing ratio may be freely selected. The amount of
the adhesive added is, when the adhesive is calculated as an oxide,
usually from 10 to 80 parts by weight per 100 parts by weight of
titanium oxide particles. If the amount used exceeds 80 parts by
weight, the ratio of titanium oxide particles buried in the
adhesive increases and the photocatalytic activity decreases,
whereas if it is less than 10 parts by weight, the effect
ascribable to the adhesive addition may not be obtained.
[0024] The method for adding the adhesive is not particularly
limited but a method of adding an adhesive to a titanium oxide sol
or solution and then coating it on an interior substrate or a
method of coating a titanium oxide sol or solution by spraying and
at the same time, coating an adhesive by another spraying may be
used.
[0025] In the case where a sol or solution of titanium oxide
particles containing brookite-type crystal is coated on an interior
material substrate and then dried, an appropriate solvent may be
added so as to increase the drying rate. When the titanium oxide
sol is dispersed in water, an organic solvent such as ethyl alcohol
is usually used.
[0026] Before coating a sol or solution of titanium oxide particles
containing brookite-type crystal on an interior material substrate,
a solution containing a silica or fluorine resin may be coated on
the interior member substrate and then dried to form a protective
film on the interior member or the like.
[0027] After the sol or solution of titanium oxide particles
containing brookite-type crystal is coated as above, the sol or
solution is dried or heat-treated so as to fix the titanium oxide
particles on the interior member substrate. The atmosphere for the
drying or heat treatment is not particularly limited. The drying or
heat treatment may be performed in atmospheric air, under vacuum or
in an inert gas but it is usually performed in atmospheric air. The
drying or heat treatment temperature is usually from 20 to
800.degree. C., preferably from 20 to 150.degree. C., and the
drying or heat treatment time is usually from 5 minutes to 24
hours, preferably from 15 minutes to 12 hours.
[0028] In the case of using an interior member substrate with heat
resistance, such as metal, ceramics or glass, the titanium oxide
particle may be calcined after the drying or heat treatment. The
calcining is performed to more firmly bond the titanium oxide
particle to the interior member substrate or the like and in the
case of a titanium oxide particle thin film, the calcining is
performed to improve the hardness. The atmosphere for the calcining
is not particularly limited and the calcining may be performed in
atmospheric air, under vacuum or in an inert gas but is usually
performed in atmospheric air. The calcining temperature varies
depending on the kind of interior member substrate or the like,
however, it is usually from 200 to 800.degree. C. If the calcining
temperature is less than 200.degree. C., the effect of improving
the adhesion of titanium oxide particles or the hardness of
titanium oxide thin film may not be attained by the calcining,
whereas if it exceeds 800.degree. C., the brookite-type crystal
transfers to the rutile-type crystal and the photocatalytic
performance is disadvantageously reduced. The burning time is not
particularly limited but is usually from 1 to 60 minutes.
[0029] In the thus-obtained interior member or indoor equipment
where titanium oxide particles containing brookite-type crystal are
present on the surface thereof, when the titanium oxide particles
are present as a thin film, the thickness of the film is usually
from 0.05 to 2 .mu.m. If the film thickness is less than 0.05
.mu.m, a sufficiently high photocatalytic performance may not be
attained, whereas if it exceeds 2 .mu.m, the photocatalysis takes
place only in the vicinity of the surface of the titanium oxide
thin film, as a result, titanium oxide not participating in the
photocatalysis increases disadvantageously in view of profitability
and the thin film is readily stripped off from the interior member
substrate or the like.
[0030] The titanium oxide particles present on the interior member
substrate may not be a thin film but may be, for example, in the
form of islands.
[0031] The interior member or indoor equipment with titanium oxide
particles containing a brookite-type crystal present on the surface
thereof of the present invention can decompose an organic material
or nitrogen oxide in air, adsorbed to the interior member or the
like by photocatalysis of the titanium oxide particle. The interior
member is not particularly limited as long as it is used indoors or
in a car, a plane, a ship or a tunnel. Examples of interior members
for indoor use such as use in a room, a bath or a kitchen, include
wall paper, floors, wall tiles, window glass, curtains, blinds,
luminaires, air-cooling and heating appliances such as air
conditioners and stoves, OA instruments such as personal computers,
AV instruments such as television and stereo, telephones, clocks,
beds, lockers, cages, tableware, ashtrays, sinks, cooking ranges,
fans and hoods thereof, dining tables or chairs, desks, household
Buddhist shrines, family altars, cisterns such as goldfish basin,
dressers, bathtubs, wash stands and stools. Examples of the
interior member for use in laboratories and the like include draft
chambers and glove boxes. Examples of interior member for use in a
car, a plane or a ship include interior members such as seats,
windshield glass, steering wheels, cover glasses of gauges, and
radiation fins of a regenerator. Examples of interior member for
use in a tunnel include inner walls, cover glass of illuminators,
indicators, guide signs and a signboards.
[0032] The interior member or indoor equipment of the present
invention is characterized by the use of titanium oxide particles
containing brookite-type crystal, so that this interior member or
the like reveals excellent photocatalysis even under irradiation
with weak ultraviolet ray having an irradiation energy of from 0.01
to 0.2 mW/cm.sup.2 at a wavelength of 365 nm as compared with
interior members with titanium oxide particles of anatase or
rutile-type crystal present on the surface thereof.
[0033] The interior member or indoor equipment thus having titanium
oxide particles containing brookite-type crystal present on the
surface thereof of the present invention enables photocatalysis to
proceed efficiently even with a weak ultraviolet ray present in the
interior room illuminator generally present in the living space,
exhibits an excellent percentage decomposition for organic
materials or nitrogen oxide adsorbed on an interior member or the
like, and is suitable for use in a room, a car, a plane, a ship or
a tunnel.
EXAMPLES
[0034] The present invention is described in greater detail below
by referring to the Examples. Unless otherwise indicated, all
parts, percents, ratios and the like are by weight.
Example A:
[0035] 954 ml of distilled water was charged into a glass reaction
tank having a volume of 1 l equipped with a reflux condenser and
heated to 95.degree. C. Then, the reaction tank was stirred at
about 200 rpm and while keeping the liquid temperature in the tank
at 95.degree. C., 46 ml of an aqueous titanium tetrachloride
solution was added dropwise to the reaction tank at a rate of about
2 ml/min. Thus, a solution having a titanium tetrachloride
concentration of 0.25 mol/l (2 wt % in terms of titanium oxide) was
obtained. After the completion of dropwise addition, the solution
was heated to the vicinity of the boiling point (104.degree. C.)
and kept at this temperature for 60 minutes to hydrolyze the
titanium tetrachloride. The sol obtained was cooled and the
chlorine produced by the hydrolysis was removed by electrodialysis
using an electrodialyzer Model G3 manufactured by Asahi Chemical
Industry Co., Ltd. As a result, a water dispersion titanium oxide
sol having a pH of 4.0 (chlorine ion: about 400 ppm) was obtained.
On observation of particles in the sol through a transmission type
electron microscope, the particle size of the particles was found
to be from 0.01 to 0.03 .mu.m.
[0036] In order to examine the crystal structure of the titanium
oxide particles present in the sol, the sol was dried in a vacuum
dyer at 60.degree. C. and the titanium oxide particles present were
analyzed by X-ray diffraction. The X-ray diffraction was performed
using an X-ray diffractometer manufactured by Rigaku Denki KK
(RAD-B rotor flex) with a Cu bulb. As a result, a peak indicating
the diffraction of a (121) face of brookite-type crystal was
detected at 2.theta.=30.8.degree.. A peak indicating the
diffraction of a (110) face, which is the main peak of rutile-type
crystal, was not detected. Furthermore, the main peak of
anatase-type crystal which overlaps the main peak of brookite-type
crystal, could not be distinguished but peaks other than the main
peak, indicating the diffraction of an anatase-type crystal were
not detected either.
[0037] For coating the water dispersion titanium oxide sol
containing brookite titanium oxide obtained above on a substrate,
tetramethoxysilane as an adhesive, which is a silicon-type
adhesive, and ethyl alcohol for improving the drying rate were
added to prepare a coating material having the composition shown in
Table 1 below.
1TABLE 1 Tetramethoxy- Example and Titanium Oxide (TiO.sub.2)
silane, in Ethyl Comparative (mol/l) terms of SiO.sub.2 Alcohol
Example Brookite Anatase Rutile (wt %) (wt %) Example A 2.5 -- --
4.0 75.0 Comparative -- 5.0 -- 10.0 75.0 Example A Comparative --
-- 2.5 4.0 75.0 Example B
Comparative Example A
[0038] For coating a water dispersion titanium oxide sol (specific
surface area: about 270 m.sup.2/g) comprising an anatase-type
crystal and not containing brookite-type crystal on an interior
member substrate, tetramethoxysilane as an adhesive, which is a
silicon-type adhesive, and ethyl alcohol for improving the drying
rate were added to prepare a coating material having the
composition shown in Table 1 above.
Comparative Example B
[0039] For coating a water dispersion titanium oxide sol (specific
surface area: about 10 m.sup.2/g) comprising a rutile-type crystal
and not containing a brookite-type crystal on an interior member
substrate, tetramethoxysilane as an adhesive, which is a
silicon-type adhesive, and ethyl alcohol for improving the drying
rate were added to prepare a coating material having the
composition shown in Table 1 above.
Example 1
[0040] 2 ml of the coating material obtained in Example A was
coated on a slide glass in a size of 76.times.26 mm by using flow
coating method and after holding the glass vertically for 10
minutes, the extra coating material was removed. Then, the glass
was kept at room temperature for 24 hours and the resulting glass
having brookite titanium oxide particles present on the surface
thereof was used as a sample for evaluation. On this glass, a few
drops of ink (red) for an ink jet printer were coated and an
ultraviolet ray was irradiated thereon from a UV light. After the
irradiation, the decomposition degree of the ink was visually
examined and evaluated as the organic material decomposing activity
according to a three-stage rating. The irradiation was performed
under three kinds of conditions. With respect to the irradiation
energy of the ultraviolet ray, energy at a wavelength of 365 nm was
measured using a sensor. The results obtained are shown in Table 2
below.
Example 2
[0041] The organic material decomposing activity was evaluated in
the same manner as in Example 1 except that a tile in a size of
76.times.26 mm was used in place of the glass. The results obtained
are shown in Table 2 below.
Example 3
[0042] The organic material decomposing activity was evaluated in
the same manner as in Example 1 except that stainless in a size of
76.times.26 mm steel was used in place of the glass. The results
obtained are shown in Table 2 below.
Example 4
[0043] The organic material decomposing activity was evaluated in
the same manner as in Example 1 except that a plastic in a size of
76.times.26 mm was used in place of the glass. The results obtained
are shown in Table 2.
Comparative Example 1
[0044] The organic material decomposing activity was evaluated in
the same manner as in Example 1 except that a glass having anatase
titanium oxide particles present on the surface thereof was
obtained using the coating material obtained in Comparative Example
A in place of the coating material obtained in Example A and used
as a sample for evaluation. The results obtained are shown in Table
2 below.
Comparative Example 2
[0045] The organic material decomposing activity was evaluated in
the same manner as in Example 1 except that a glass having rutile
titanium oxide particles present on the surface thereof was
obtained using the coating material obtained in Comparative Example
B in place of the coating material obtained in Example A and used
as a sample for evaluation. The results obtained are shown in Table
2 below.
[0046] In Table 2, the symbols indicate the following results.
[0047] A: satisfactory fading;
[0048] B: partly no fading;
[0049] C: no fading.
[0050] In Table 2, conditions (1) to (5) were as follows:
[0051] Condition (1):
[0052] An ultraviolet ray having irradiation energy of 2.0
mW/cm.sup.2 at 365 nm was irradiated for 10 minutes.
[0053] Condition (2):
[0054] An ultraviolet ray having an irradiation energy of 1.0
mW/cm.sup.2 at 365 nm was irradiated for 30 minutes.
[0055] Condition (3):
[0056] An ultraviolet ray having irradiation energy of 0.1
mW/cm.sup.2 at 365 nm was irradiated for 120 minutes.
[0057] Condition (4):
[0058] An ultraviolet ray having irradiation energy of 0.003
mW/cm.sup.2 at 365 nm was irradiated for 360 minutes.
[0059] Condition (5):
[0060] An ultraviolet ray having irradiation energy of 0.001
mW/cm.sup.2 at 365 nm was irradiated for 2 days.
2TABLE 2 Organic Material Decomposing Example and Activity
Comparative Interior Member Conditions Example Substrate (1) (2)
(3) (4) (5) Example 1 glass A A A A B Example 2 tile A A A A B
Example 3 stainless steel A A A A B Example 4 plastic A A A A B
Comparative glass A A C C C Example 1 Comparative glass C C C C C
Example 2
Example 5
[0061] 2 ml of the coating material obtained in Example A was
coated on a slide glass in a size of 76.times.26 mm using a flow
coating method and after holding the glass vertically for 10
minutes, the extra coating material was removed. Then, the glass
was kept at room temperature for 24 hours and the resulting glass
having brookite titanium oxide particles present on the surface
thereof was used as a sample for evaluation. This sample for
evaluation was placed in a chamber having a volume of 1,200
cm.sup.3 and nitrogen oxide gas was charged thereinto in a
concentration of 50 ppm.
[0062] Thereafter, an ultraviolet ray was irradiated from a UV
light on the sample in the chamber. After the irradiation, the
decomposition degree of the nitrogen oxide gas was determined by
measuring the amount of the residual nitrogen oxide gas and
evaluated as the organic material decomposing activity according to
a three-stage rating. The irradiation was performed under three
kinds of conditions. With respect to the irradiation energy of the
ultraviolet ray, energy at a wavelength of 365 nm was measured
using a sensor. The results obtained are shown in Table 3
below.
Example 6
[0063] The nitrogen oxide decomposing activity was evaluated in the
same manner as in Example 5 except that aluminum in a size of
76.times.26 mm was used in place of the slide glass. The results
obtained are shown in Table 3 below.
Example 7
[0064] The nitrogen oxide decomposing activity was evaluated in the
same manner as in Example 5 except that a ceramic in a size of
76.times.26 mm was used in place of the slide glass. The results
obtained are shown in Table 3 below.
Example 8
[0065] The nitrogen oxide decomposing activity was evaluated in the
same manner as in Example 5 except that plastic in a size of
76.times.26 mm was used in place of the slide glass. The results
obtained are shown in Table 3.
Comparative Example 3
[0066] The nitrogen oxide decomposing activity was evaluated in the
same manner as in Example 5 except that aluminum having anatase
titanium oxide particles present on the surface thereof was
obtained using the coating material obtained in Comparative Example
A in place of the coating material obtained in Example A and using
aluminum in a size of 76.times.26 mm in place of the slide glass,
and used as a sample for evaluation. The results obtained are shown
in Table 3 below.
Comparative Example 4
[0067] The nitrogen oxide decomposing activity was evaluated in the
same manner as in Example 5 except that a glass having rutile
titanium oxide particles present on the surface thereof was
obtained using the coating material obtained in Comparative Example
B in place of the coating material obtained in Example A and used
as a sample. The results obtained are shown in Table 3 below.
[0068] In Table 3, the symbols indicate the following results.
[0069] A: percentage decomposition of 80% or more;
[0070] B: percentage decomposition of from 50% to less than
80%;
[0071] C: percentage decomposition of less than 50%.
[0072] In Table 3, the conditions (1) to (5) were as follows:
[0073] Condition (1):
[0074] An ultraviolet ray having irradiation energy of 2.0
mW/cm.sup.2 at 365 nm was irradiated for 10 minutes.
[0075] Condition (2):
[0076] An ultraviolet ray having irradiation energy of 1.0
mW/cm.sup.2 at 365 nm was irradiated for 30 minutes.
[0077] Condition (3):
[0078] An ultraviolet ray having irradiation energy of 0.1
mW/cm.sup.2 at 365 nm was irradiated for 120 minutes.
[0079] Condition (4):
[0080] An ultraviolet ray having irradiation energy of 0.003
mW/cm.sup.2 at 365 nm was irradiated for 360 minutes.
[0081] Condition (5):
[0082] An ultraviolet ray having irradiation energy of 0.001
mW/cm.sup.2 at 365 nm was irradiated for 2 days.
3TABLE 3 Nitrogen Oxide Example and Interior Decomposing Activity
Comparative Member Conditions Example Substrate (1) (2) (3) (4) (5)
Example 5 glass A A B B B Example 6 aluminum A A B B B Example 7
ceramic A A B B B Example 8 plastic A A B B B Comparative aluminum
A B C C C Example 3 Comparative glass C C C C C Example 4
[0083] As is apparent from the results in Tables 2 and 3, interior
members having titanium oxide particles containing brookite-type
crystal of the present invention present on the surface thereof
exhibited excellent decomposing activity for the organic material
and nitrogen oxide even under irradiation with weak ultraviolet ray
having an irradiation energy of only 0.001 mW/cm.sup.2 at 365
nm.
[0084] While the invention has been described in detail and with
reference to specific embodiments thereof, it will be apparent to
one skilled in the art that various changes and modifications can
be made therein without departing from the spirit and scope
thereof.
* * * * *