U.S. patent application number 12/494699 was filed with the patent office on 2009-10-22 for method for manufacturing ultra-hydrophilic thin film coated metal product, and ultra-hydrophilic thin film coated metal product.
Invention is credited to Young-Man JEONG, Hyun-Woo Jun, Su-Won Lee, Jung-Gena Oh, Deok-Hyun Youn.
Application Number | 20090263649 12/494699 |
Document ID | / |
Family ID | 35125104 |
Filed Date | 2009-10-22 |
United States Patent
Application |
20090263649 |
Kind Code |
A1 |
JEONG; Young-Man ; et
al. |
October 22, 2009 |
METHOD FOR MANUFACTURING ULTRA-HYDROPHILIC THIN FILM COATED METAL
PRODUCT, AND ULTRA-HYDROPHILIC THIN FILM COATED METAL PRODUCT
Abstract
The present invention discloses a method for manufacturing an
ultra-hydrophilic thin film coated metal product, and an
ultra-hydrophilic thin film coated metal product. In order to
easily produce an air conditioning metal material having excellent
hydrophilic and aging properties on an industrial production scale,
an anticorrosive thin film is selectively formed on both surfaces
of a metal substrate sheet, and a ultra-hydrophilic T--O--(C)--(H)
group compound thin film is coated on both surfaces on which the
anticorrosive thin film has been or has not been formed, and
mechanically processed into a target shape.
Inventors: |
JEONG; Young-Man;
(Gimhae-shi, KR) ; Oh; Jung-Gena; (Changwon-shi,
KR) ; Jun; Hyun-Woo; (Changwon-Shi, KR) ; Lee;
Su-Won; (Changwon-Shi, KR) ; Youn; Deok-Hyun;
(Anyana-Shi, KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
35125104 |
Appl. No.: |
12/494699 |
Filed: |
June 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11547565 |
Oct 24, 2007 |
|
|
|
12494699 |
|
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|
|
Current U.S.
Class: |
428/336 ;
428/470 |
Current CPC
Class: |
C23C 16/4557 20130101;
F28F 13/18 20130101; Y10T 428/12986 20150115; Y10T 428/12667
20150115; C23C 16/30 20130101; Y10T 428/31678 20150401; C23C 16/545
20130101; C23C 16/50 20130101; F28F 2245/02 20130101; Y10T 428/265
20150115; Y10T 428/12736 20150115 |
Class at
Publication: |
428/336 ;
428/470 |
International
Class: |
B32B 15/04 20060101
B32B015/04; B32B 5/00 20060101 B32B005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 6, 2004 |
KR |
10-2004-0023446 |
Claims
1. A metal product, on which a hydrophilic Ti--O--(C)--(H) group
compound thin film containing Ti and O, and further containing a
remainders comprising C and/or H and an unavoidable impurities is
coated.
2. The metal product of claim 1, wherein the Ti--O--(C)--(H) group
compound thin film contains 15 to 22 atomic % of Ti and 45 to 65
atomic % of O.
3. The metal product of claim 1, wherein the Ti--O--(C)--(H) group
compound thin film contains 20 to 25 atomic % of C.
4. The metal product of claim 1, wherein the Ti--O--(C)--(H) group
compound thin film contains 20 to 25 atomic % of H.
5. The metal product of claim 1, wherein the thickness of the thin
film ranges 1 to 100 nm.
6. The metal product of claim 1, wherein the thin film has an
amorphous micro-structure.
7. The metal product of claim 1, wherein the metal product is an
aluminum sheet.
8. The metal product of claim 7, wherein the thin film coated
aluminum sheet is mechanically machined into a fin for a heat
exchanger.
Description
[0001] This application is a Divisional of co-pending application
Ser. No. 11/547,565, filed on Oct. 24, 2007 and application Ser.
No. 11/547,565 claims priority under 35 USC 119 to Patent
Application No. 10-2004-0023446 filed in Korea on Apr. 6, 2004, all
of which are hereby expressly incorporated by reference in their
entirety.
TECHNICAL FIELD
[0002] The present invention relates to a method for manufacturing
an ultra-hydrophilic thin film coated metal product, and an
ultra-hydrophilic thin film coated metal product.
BACKGROUND ART
[0003] Metal materials having hydrophilic surface layers on their
surfaces have been efficiently used in the whole industrial fields,
which will now be explained by using a heat exchanger as an
example.
[0004] A heat exchanger exchanging heat by making two fluids having
different temperatures directly or indirectly contact each other
has been widely used in various industrial fields, especially for
heating, air conditioning, power generation, waste heat recovery
and chemical processes.
[0005] An air conditioning heat exchanger forms a fin that is an
enlarged surface at the air side to improve heat transmission. When
the air having humidity passes through the fin in the heat exchange
operation, heat transmission occurs by low temperature refrigerants
supplied into a tube. When a temperature of the surface of the fin
is equal to or lower than a dew point temperature of the air having
humidity, droplets are formed on the surface of the heat exchanger
to intercept flow of the air, which increases a pressure drop that
is a pressure difference between the inlet and outlet of the heat
exchanger. Accordingly, power of a fan must be increased to supply
the same flux, which results in large power consumption.
[0006] In order to solve the above problem, as disclosed in
Japanese Laid-Open Patent Application 61-8598, flow of condensed
water formed on a surface of a fin of a heat exchanger is improved
by performing an anti-corrosive process on an aluminum sheet of the
fin by using Cr.sup.+6 to improve corrosion resistance, and
performing a silicate-group coating process thereon to give
hydrophilicity, which is called a pre-coated material (PCM).
[0007] The PCM basically requires Cr.sup.+6 to obtain corrosion
resistance. However, Cr.sup.+6 will be prevented since 2006 due to
environmental problems. There are thus increasing demands for a
material substituting for Cr.sup.+6. Until now. Cr.sup.+3 or resin
type has been suggested. In the preparation of the PCM,
tetrachloroethane (TCE) inevitably used to wash aluminum also
causes environmental contamination. In addition, the PCM showing
excellent hydrophilic performance at an initial stage gradually
loses the hydrophilic property, namely, has an aging
characteristic. Recently, chemical products have been mostly used
as materials for wallpaper. The silicate material for giving
hydrophilicity is volatilized and chemically coupled with the wall
paper, thereby discoloring the wall paper. Also, the volatilized
materials displease people.
[0008] Continuous attempts have been made to satisfy various
demands by forming a functional surface layer (for example,
hydrophilicity or hydrophobicity) on the existing material.
Exemplary methods for forming the functional surface layer include
1) depositing the functional surface layer on the existing
material, and 2) giving new physical and chemical properties by
improving the surface film of the existing material.
[0009] However, in the latter, as the time elapses, the surface
property is changed and returns to the original property. For
example, in the case that a metal such as aluminum is processed
according to an ion beam assisted reaction process, hydrophilicity
of the surface of the metal is improved. It is because a natural
oxide film is etched on the surface of the aluminum and the
functional film is formed thereon. As the time elapses, an oxide
film is naturally grown on the surface of the aluminum. As a
result, hydrophilicity improvement effects obtained by etching the
natural oxide film are deteriorated. The functional film formed on
the surface of the aluminum is made of an extremely thin layer
(<a few nm) having very low mechanical resistance to
environmental variations (water, temperature, etc.) by time.
Accordingly, the improved hydrophilic property is reduced and
returns to the original surface property.
[0010] In order to solve the foregoing problem, efforts have been
continuously made to form on a metal material a hydrophilic or
hydrophobic functional surface layer that can maintain a physically
chemically stable state.
[0011] For example, as suggested in Japanese Laid-Open Patent
Application 2001-280879, in a heat exchanger mounting a fin made of
a conductive metal material on a metal tube that is a refrigerant
passage, compound vapor containing titanium that is raw gas is
supplied to flow in parallel to the surface of the fin of the heat
exchanger in the air. Therefore, the heat exchanger coating the
titanium dioxide thin film on the surface of the fin is
manufactured according to a plasma CVD technology. The above patent
application teaches that the heat exchanger can obtain excellent
hydrophilic, antibacterial and deodorizing properties.
[0012] However, in a state where the fin is mounted on the tube to
compose the heat exchanger, the titanium dioxide thin film is
deposited on the fin of the heat exchanger. Thus, the titanium
dioxide thin film cannot be uniformly deposited on the whole
surface of the fin, which deteriorates hydrophilic and aging
properties. Furthermore, productivity for direct application to the
industrial production is not attained.
DISCLOSURE OF THE INVENTION
[0013] The present invention is achieved to solve the above
problems. An object of the present invention is to provide a method
for manufacturing an ultra-hydrophilic thin film coated metal
product having excellent hydrophilic and aging properties, and an
ultra-hydrophilic thin film coated metal product.
[0014] Another object of the present invention is to easily produce
an ultra-hydrophilic thin film on an industrial production scale,
by forming the ultra-hydrophilic thin film on a sheet-shaped metal
substrate and mechanically processing the metal substrate into a
target shape.
[0015] Yet another object of the present invention is to uniformly
form an ultra-hydrophilic thin film on both surfaces of a
sheet-shaped metal substrate.
[0016] In order to achieve the above-described objects of the
invention, there is provided a method for manufacturing a
ultra-hydrophilic thin film coated metal product, which
continuously coats a ultra-hydrophilic titanium compound thin film
on both surfaces of a continuously-supplied sheet-shaped metal
substrate in a vacuum chamber by using plasma, and mechanically
processes the thin film coated sheet into a target shape. Here, the
thin film is a Ti--O group compound thin film. Preferably, the thin
film is a Ti--O group compound thin film containing 15 to 22 atomic
% of Ti and 45 to 65 atomic % of O. In addition, the thin film
further contains C and/or H. Preferably, the thin film contains 15
to 22 atomic % of Ti and 45 to 65 atomic % of O, and further
contains 20 to 25 atomic % of C and/or 20 to 25 atomic % of H.
Here, the thin film has a thickness of 1 to 100 nm.
[0017] The metal substrate can be an aluminum substrate, and the
metal product can be a fin for a heat exchanger.
[0018] The coating process is performed by injecting reactive gas,
gas-phase titanium precursor and carrier gas into the vacuum
chamber. Preferably, the gas injection ratio satisfies carrier
gas:reactive gas =1:3, and also satisfies gas-phase titanium
precursor:carrier gas =3:1.
[0019] Preferably, the reactive gas is air or O.sub.2, the carrier
gas is selected from the group consisting of He, N.sub.2 and Ar,
and the gas-phase titanium precursor is prepared by passing
liquid-phase titanium tetraisopropoxide through a bubbler. In
addition, the injection amount of the gas-phase titanium precursor
into the vacuum chamber is controlled by adjusting the amount of
the liquid-phase titanium tetraisopropoxide supplied to the
bubbler. The carrier gas is injected before the liquid-phase
titanium tetraisopropoxide is injected into the bubbler, for
transferring the liquid-phase titanium tetraisopropoxide to the
bubbler.
[0020] There is also provided a ultra-hydrophilic thin film coated
metal product, which is coated with a ultra-hydrophilic Ti--O group
compound thin film containing 15 to 22 atomic % of Ti and 45 to 65
atomic % of O at a thickness of 1 to 100 nm by using plasma.
Preferably, the thin film further contains 20 to 25 atomic % of C
and/or 20 to 25 atomic % of H. The thin film has an amorphous
structure and the metal sheet is an aluminum sheet. The thin film
coated aluminum sheet is a metal sheet that can be mechanically
processed into a fin for a heat exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention will become better understood with
reference to the accompanying drawings which are given only by way
of illustration and thus are not limitative of the present
invention, wherein:
[0022] FIG. 1 is a concept view illustrating a device for
continuously coating a ultra-hydrophilic titanium compound thin
film on a sheet-shaped metal substrate by using plasma in
accordance with the present invention;
[0023] FIG. 2 is a graph showing XPS data for analyzing composition
of the surface of the anticorrosive hydrophilic thin film coated
metal sheet in accordance with the present invention;
[0024] FIG. 3 is a graph showing AES data for analyzing thickness
of the coated thin film in accordance with the present
invention;
[0025] FIG. 4 is an SEM photograph showing the microstructure of
the coated titanium compound thin film in accordance with the
present invention;
[0026] FIGS. 5a and 5b are photographs respectively showing
dispersion of droplets when the surface is hydrophilic (FIG. 5a)
and when the surface is hydrophobic (FIG. 5b) in a surface
hydrophilicity/hydrophobicity test in accordance with the present
invention;
[0027] FIG. 6 is a graph showing aging properties of the bare Al
sheet, the conventional PCM sheet and the titanium compound thin
film coated sheet of the present invention;
[0028] FIG. 7 is a graph showing aging properties of the titanium
compound thin film coated sheet of the present invention and the
conventional PCM sheet; and
[0029] FIG. 8 is a graph showing variable test results of titanium
compound thin film coating in accordance with the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] A method for manufacturing a ultra-hydrophilic thin film
coated metal product, and a ultra-hydrophilic thin film coated
metal product in accordance with the present invention will now be
described in detail with reference to the accompanying
drawings.
[0031] FIG. 1 is a concept view illustrating a plasma
polymerization device for coating an ultra-hydrophilic Ti--O--C
group compound thin film on a sheet-shaped metal substrate in
accordance with the present invention. The polymerization device
includes a coating chamber maintained in a vacuum state, plasma
being formed inside the coating chamber, a reactive gas injecting
means for injecting reactive gas into the coating chamber, a
gas-phase precursor injecting means for injecting a gas-phase
precursor into the coating chamber, and a carrier gas injecting
means for injecting carrier gas for transferring the gas-phase
precursor into the coating chamber.
[0032] A vacuum pump 4 for forming a vacuum inside the coating
chamber 2 is connected to the coating chamber 2, and a metal sheet
8 is continuously supplied between electrodes 6 installed at the
upper and right portions or the right and left sides. In FIG. 1,
the electrodes 6 are installed at the upper and lower portions of
the metal sheet 8, and the metal sheet 8 is supplied in the
horizontal direction. After an ultra-hydrophilic titanium compound
thin film is continuously coated on both surfaces of the metal
sheet 8 by the plasma generated between the electrodes 6, the metal
sheet 8 is discharged from the coating chamber 2. Power 10 is
applied to the electrodes 6.
[0033] Preferably, a reactive gas cylinder 20 containing reactive
gas that can form air or oxygen injects the reactive gas to the
coating chamber 2 through a valve 22.
[0034] In addition, a liquid-phase titanium precursor that is
liquid-phase titanium tetraisopropoxide [Ti(OC.sub.3H.sub.7).sub.4]
contained in a containing vessel 30 pressurized by a pressurizer 32
is injected into a bubbler 40 through a liquid-phase mass flow
controller (MFC) 38 due to pressure differences. A gas-phase
titanium precursor bubbled by the bubbler 40 is injected into the
coating member 2. Preferably, carrier gas that can form He, Ar or
N.sub.2 is injected through a tube between the liquid-phase MFC 38
and the bubbler 40, for helping the gas-phase titanium precursor to
be injected into the coating chamber 2. The carrier gas is
contained in a carrier gas cylinder 50 and injected into the tube
through a valve 52. A heater coil 42 is coiled around the bubbler
40 to heat and bubble the liquid-phase titanium precursor. As
described above, the coating process using nano plasma is executed
by injecting the reactive gas that can form air or O.sub.2, the
gas-phase titanium precursor and the carrier gas into the coating
chamber 2. The injection amount of the gas-phase titanium precursor
into the coating chamber 2 is controlled by adjusting the amount of
the liquid-phase precursor supplied to the bubbler 40, namely, the
liquid-phase titanium tetraisopropoxide.
[0035] Here, the reactive gas, the gas-phase titanium precursor and
the carrier gas can be combined outside the coating chamber 2 and
injected into the coating chamber 2 through one tube 60 as shown in
FIG. 1, or can be injected into the coating chamber 2 through
different tubes and combined inside the coating chamber 2 through
one tube. Still referring to FIG. 1, the combining tube 60 is
connected through one side hole of the coating chamber 2.
Preferably, the outlet of the tube 60 is adjacent to the top and
bottom surfaces of the coated metal sheet 8 in order to discharge
the mixed gas injected through the tube 60 in the up/down direction
of the metal sheet 8.
[0036] The gas-phase titanium precursor is condensed at a low
temperature. When the tube 60 is maintained at a normal
temperature, the gas-phase titanium precursor is condensed on the
inner wall of the tube 60. In order to prevent condensation of the
gas-phase titanium precursor, a hot wire 64 is coiled around the
outer wall of the tube 60 through which the gas-phase titanium
precursor gas flows, for maintaining a predetermined temperature. A
tube 66 through which the liquid-phase titanium precursor flows is
also formed in the same manner. That is, a hot wire 68 is coiled
around the outer wall of the tube 66, for maintaining a
predetermined temperature, thereby preventing the titanium
precursor from being condensed on the inner wall of the tube
66.
[0037] In accordance with the present invention, the
ultra-hydrophilic titanium compound thin film is continuously
coated on the metal sheet 8 continuously supplied to the coating
chamber 2 by using the plasma, and the thin film coated metal sheet
8 is mechanically processed into a target shape, for example, a fin
of an air conditioning heat exchanger.
[0038] As illustrated in FIG. 1, the vacuum pump 4 for forming the
vacuum inside the coating chamber 2 is connected to the coating
chamber 2, and the metal sheet 8 is continuously supplied between
the electrodes 6 installed at the upper and lower sides. After the
ultra-hydrophilic titanium compound thin film is continuously
coated on both surfaces of the metal sheet 8 by the plasma
generated between the electrodes 6, the metal sheet 8 is discharged
from the coating chamber 2. Here, power 10 is applied to the
electrodes 6.
[0039] Preferably, the reactive gas cylinder 20 containing the
reactive gas that can form air or oxygen injects the reactive gas
to the coating chamber 2 through the valve 22.
[0040] In addition, the liquid-phase titanium precursor that is
liquid-phase titanium tetraisopropoxide [Ti(OC.sub.3H.sub.7).sub.4]
contained in the containing vessel 30 pressurized by the
pressurizer 32 is injected into the bubbler 40 through the
liquid-phase MFC 38 due to pressure differences. The gas-phase
titanium precursor bubbled by the bubbler 40 is injected into the
coating member 2. Preferably, the carrier gas that can form He or
Ar is injected through the tube between the liquid-phase MFC 38 and
the bubbler 40, for helping the gas-phase titanium precursor and
the gas-phase silicon precursor to be injected into the coating
chamber 2. The carrier gas is contained in the carrier gas cylinder
50 and injected into the tube through the valve 52. The heater coil
42 is coiled around the bubbler 40 to heat and bubble the
liquid-phase titanium precursor.
[0041] Here, the reactive gas, the gas-phase titanium or silicon
precursor and the carrier gas can be combined outside the coating
chamber 2 and injected into the coating chamber 2 through one tube
60 as shown in FIG. 1, or can be injected into the coating chamber
2 through different tubes and combined inside the coating chamber 2
through one tube. Still referring to FIG. 1, the combining tube 60
is connected through one side hole of the coating chamber 2.
Preferably, the mixed gas injected through the tube 60 is
discharged in the up/down direction of the coated metal sheet 8.
That is, the mixed gas is supplied in the up/down direction of the
metal sheet 8, for generating the plasma between the upper and
lower electrodes 6, thereby forming the titanium compound thin film
on both surfaces of the metal sheet 8.
[0042] The gas-phase titanium or silicon precursor is condensed at
a low temperature. When the tube 60 is maintained at a normal
temperature, the gas-phase titanium precursor is condensed on the
inner wall of the tube 60. In order to prevent condensation of the
gas-phase titanium precursor, the hot wire 64 is coiled around the
outer wall of the tube 60 through which the gas-phase titanium
precursor gas flows, for maintaining a predetermined temperature.
The tube 66 through which the liquid-phase titanium precursor flows
is also formed in the same manner. That is, the hot wire 68 is
coiled around the outer wall of the tube 66, for maintaining a
predetermined temperature, thereby preventing the titanium or
silicon precursor from being condensed on the inner wall of the
tube 66.
[0043] Reference numerals 34 and 36 denote a valve of the
pressurizer 32 and a valve of the containing vessel 30,
respectively.
[0044] In accordance with the present invention, the
ultra-hydrophilic Ti--O--C group compound thin film is continuously
coated on the metal sheet 8 continuously supplied to the coating
chamber 2 by using the plasma, and the thin film coated metal sheet
8 is mechanically processed into a target shape, for example, a fin
of an air conditioning heat exchanger.
[0045] The ultra-hydrophilic metal sheet can be manufactured by
using the plasma polymerization device. As mentioned above, the
ultra-hydrophilic metal sheet is mechanically processed into the
fin of the heat exchanger, and physical and surface properties
thereof are measured and explained in the following examples. It
must be recognized that the scope of the present invention is not
restricted by the following examples but claims recited below.
Examples
Preparation of Plasma Coating Film
[0046] After 10.sup.-3 Torr of vacuum was formed in the coating
chamber 2 by using the vacuum pump 4, the metal sheet 8 was
connected to an anode and maintained at a predetermined distance
(30 to 150 mm) from the electrodes 6, and the heater coil 42 of the
bubbler 40 was electrically heated (80 to 120.degree. C.) to bubble
the liquid-phase precursor. The hot wires 64 and 68 coiled around
the outer walls of the tubes 60 and 66 were electrically heated (80
to 120.degree. C.) to prevent the titanium precursor from being
condensed on the inner walls of the tubes 60 and 66. The gas-phase
precursor gas, the carrier gas and the reactive gas were injected
into the coating chamber 2 through the tube, and discharged in the
up/down direction of the metal sheet 8.
[0047] Preferably, the gas-phase precursor gas and the carrier gas
were injected into the coating chamber 2 at a ratio of 3:1, and the
carrier gas and the reactive gas were injected into the coating
chamber 2 at a ratio of 1:3.
[0048] When a target operation vacuum degree was obtained by the
injected gas, the power was turned on, the metal sheet 8 was
transferred in regard to the tube 60, and the plasma was
continuously formed between the electrodes 6 by the mixed gas.
Accordingly, the ultra-hydrophilic Ti--O--C group compound thin
film was coated on both surfaces of the metal sheet 6.
[0049] In the plasma treatment, the current was 1.2 A 900V, the
flux of the carrier gas that is He or Ar gas was 800 sccm, the flux
of the reactive gas that was oxygen or air was 1500 sccm, the flux
of the gas-phase precursor gas was 1000 sccm, and the vacuum degree
inside the chamber 2 ranged from 0.2 to 0.35 Torr.
[0050] Analysis of Composition and Thickness of Coated Thin
Film
[0051] The composition of the processed thin film sample was
analyzed according to X-ray photoelectric spectroscopy (XPS) for
analogizing surface composition by measuring molecular specific
absorption and emission wavelengths by using X-rays, and the
thickness thereof was analyzed according to atomic emission
spectrometry (AES) for analyzing composition by depth by performing
sputtering at a fixed speed. FIGS. 2 and 3 show the analysis
results.
[0052] FIG. 2 is a graph showing XPS data when a titanium compound
thin film was formed after an HMDSO anticorrosive thin film. 19.4
atomic % of C, 58.3 atomic % of O and 19.8 atomic % of Ti were
analyzed. That is, the compound thin film was a Ti--O--C group
compound thin film.
[0053] Although not illustrated, when only the ultra-hydrophilic
compound thin film was coated, the Ti--O--C group compound thin
film was prepared.
[0054] In accordance with the analysis results, although slightly
varied upon the conditions, the titanium compound thin film
commonly contains 15 to 22 atomic % of Ti, 45 to 65 atomic % of O,
and 20 to 25 atomic % of C and/or 20 to 25 atomic % of H.
[0055] FIG. 3 is a graph showing representative AES data. As
described above, the AES, that analyzes composition by depth by
performing sputtering at a fixed speed, can analyze the thickness
of the thin film. In the AES data of FIG. 3, the thickness of the
thin film was 233 .ANG. (23.3 nm). The thickness of the
Ti--O--(C)--(H) group compound thin film was restricted between 100
.ANG. and 1500 .ANG.. Therefore, the preferable thickness of the
Ti--O--(C)--(H) group compound thin film ranged from 1 to 100
nm.
[0056] FIG. 4 is an SEM photograph showing the Ti--O--C group
compound thin film in accordance with the present invention. As
depicted in FIG. 4, a tight thin film was obtained with an
amorphous structure.
[0057] Hydrophilic and Aging Properties of Thin Film
[0058] The hydrophilic performance test was executed by dropping a
fixed quantity of droplets (0.1 cc) from a height of 10 mm, and
measuring a size of droplets on the surface of the sample. When the
surface of the film was hydrophilic, the size of the droplets
increased due to high dispersion, and when the surface of the film
was hydrophobic, the size of the droplets decreased due to low
dispersion. FIG. 5a shows the droplet formed on the hydrophilic
surface. The size of the droplet ranged from 9 to 11 mm. FIG. 5b
shows the droplet formed on the hydrophobic surface. The size of
the droplet ranged from 2 to 3 mm.
[0059] In order to evaluate the hydrophilic aging property, the
samples were cyclically put into distilled water for 10 minutes and
dried for 10 minutes. The hydrophilic performance of the initial
samples was compared with that of the samples obtained after 300
cycles.
[0060] FIG. 6 is a graph showing the test results. The hydrophilic
performance of the thin film of the present invention processed by
the plasma was not changed after 300 cycle accelerations. On the
other hand, the conventional PCM had excellent initial hydrophilic
performance. As a surfactant that was a hydrophilic agent was
dissolved in water, the hydrophilic performance of the conventional
PCM was deteriorated. That is, the conventional PCM was aged. The
Bare Al had a hydrophobic property at an initial stage. After
accelerations, an Al.sub.2O.sub.3 layer was formed on the surface
of the aluminum to slightly improve the hydrophilic
performance.
[0061] FIG. 7 is a graph showing 1000 cycle aging test results of
the titanium compound thin film of the present invention and the
conventional PCM thin film. The thin film of the present invention
maintained the hydrophilic performance (at least 9 mm of droplets).
On the other hand, the hydrophilic performance of the conventional
PCM thin film was sharply deteriorated according to increase of
cycles.
[0062] Hydrophilic Performance Property by Manufactured
Composition
[0063] FIG. 8 is a graph showing hydrophilic performance test
results of an Al sheet sample when a bubbler temperature, reactive
gas, carrier gas and a deposition time were varied. That is, FIG. 8
shows size variations of the droplets by variations of each
element.
[0064] The heating temperature of the bubbler 40 for bubbling the
liquid-phase precursor was set as 60.degree. C., 100.degree. C. and
120.degree. C. The liquid-phase precursor heated and bubbled at
100.degree. C. had the highest hydrophilic performance (8.7
mm).
[0065] The reactive gas was changed into O.sub.2, N.sub.2 and air.
The sample using the air as the reactive gas had the highest
hydrophilic performance (9.3 mm).
[0066] The carrier gas was changed into He and Ar. The sample using
He as the carrier gas had the highest hydrophilic performance (9.9
mm).
[0067] The deposition time of the precursor gas was changed between
30 sec and 120 sec at an interval of 30 sec. The sample passing
through 90 sec coating showed similar hydrophilic performance to
that of the sample passing through 120 sec coating (9.9 mm).
Accordingly, the coating process was preferably performed for 90
sec, to maintain the hydrophilic performance and reduce the
production time.
[0068] Here, the current of the electrodes 6 installed on both
surfaces of the sample for forming the plasma was 0.13 A, and the
vacuum inside the coating chamber 2 housing the sample was
maintained at 0.3 Torr.
[0069] In order to efficiently manufacture the ultra-hydrophilic
thin film coated metal product, the liquid-phase precursor was
heated and bubbled at 100.degree. C. in the bubbler 40, the air was
used as the reactive gas, He was used as the carrier gas, and the
coating process was executed in the chamber 2 for 90 sec.
[0070] In the above test, the coating process was executed on the
suitable sample. In the mass-production of the products, the
heating temperature of the bubbler, the reactive gas, the carrier
gas and the deposition time can be varied within the approximate
range according to production environments and variable factors by
continuous mass-production.
[0071] Advantageous Effects
[0072] As discussed earlier, in accordance with the present
invention, the air conditioning metal material coated with the thin
film having excellent hydrophilic and aging properties can be
easily produced on an industrial production scale.
[0073] In addition, the ultra-hydrophilic thin film can be
uniformly formed on both surfaces of the sheet-shaped metal
substrate.
[0074] Although the preferred embodiments of the present invention
have been described, it is understood that the present invention
should not be limited to these preferred embodiments but various
changes and modifications can be made by one skilled in the art
within the spirit and scope of the present invention as hereinafter
claimed.
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