Note: Descriptions are shown in the official language in which they were submitted.
CA 02461588 2004-03-22
ANTI-MICROBIAL SANITARY WAF:E AND
METHOD FOR l~~IAhfiG THE SAME
BACKGROUND OF THE INVENTIOI\T
1. Field of the invention
This invention relates to an anti-microbial sanitary ware and a
method for making the same, more particularly to an anti-microbial
sanitary ware with a metal particle-containing anti-microbial f.il.m
and a method for making the same.
2. Description of the related art
Conventional sanitary wares, such as towel bars, robe hangers,
faucets, shower heads, shelves, soap holders, paper holders, tumbler
holders, door knobs etc., are normally coated with a protective film
made from metal nitride or metal carbide so as to provide a smooth
surface and resistance to corrosion and wearing for the sanitary
wares. The protective film is formed on a substrate of the sanitary
ware by sputtering techniques, such as unbalanced magnetron
sputtering.
Since sanitary wares are constantly exposed to moisture-rich
atmosphere, it is desirable to prevent or mitigate the growth of
bacteria or fouling on the sanitary wares while maintaining the
resistance to corrosion and wearing.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide an
anti-microbial sanitary ware with an anti-microbial film that is
capable of mitigating the growth of bacteria while maintaining the
resistance to corrosion and wearing.
According to one aspect of the present invention, there is
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provided an anti-microbial sanitary ware that comprises: a substrate;
and an anti-microbial fit~n formed on the substrate and comprising a
protective layer and anti-microbial metal particles that are dispersed
in the protective layea-. The protective layer is made from a
compound selected from the group consisting of metal nitrides and
metal carbides. The anti-microbial metal particles are made from a
metal selected from the group consisting of silver, zinc, and copper.
According to ano~:her aspect of the present invention, there; is
provided a method for making an anti-microbial article. The method
comprises the steps of: placing a substrate in a sputtering chamber in
a sputter; and simultaneously sputtering a first metal target of a first
metal and a second metal target of a second metal through
closed-field unbalanced magnetron sputtering techniques, which form
a continuously closed magnetic field around the substrate, so as to
react the first metal into a metal compound which is subsequently
deposited on the substrate to form a protective layer, and so as to
generate metal particles of the second metal that are dispersed in the
protective layer. The :second metal is selected from the group
consisting of silver, zinc, and copper. The metal compound is
selected from the group consisting of metal nitrides and metal
carbides.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate an embodiment of the invention,
Fig. 1 is a block diagram illustrating consecutive steps of the
preferred embodiment of a method for making an anti-microbial
sanitary ware according to the present invention; and
Fig. 2 is a cutaway view of the preferred embodiment of the
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anti-microbial sanitary ware formed according to the method of this
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Fig. 2 illustrates the preferred embodiment of an
S anti-microbial sanitary ware, such as the aforesaid sanitary wares,
according to the present invention. The anti-microbial sanitary ware
includes: a substrate 2; and an anti-microbial film formed oil the
substrate 2 and comprising a protective layer 3 and anti-microbial
metal particles 4 that are dispersed in the protective layer 3. The
protective Iayer 3 is made from a metal compound selected from the
group consisting of metal nitrides and metal carbides.
Referring to Fig. 1, in combination with Fig. 2, the method of
forming the anti-microbial sanitary ware involves the use of
closed-field unbalanced magnetron sputtering (CFUBMS) techniques,
and includes the steps of: placing the substrate 3 in a sputter (not
shown); and simultaneously sputtering a first metal target of a first
metal and a second metal target of a second nnetal so as to react the
first metal into the metal compound which is subsequently deposited
on the substrate 2 to form the protective layer 3, and so as to
generate the anti-microbial metal particles 4 of the second metal that
are dispersed in the protective layer 3. The metal particles 4 thus
formed have a particle size less than 104 nanometers.
Preferably, the second metal, which forms the anti-microbial
metal particles 4, is selected from the group consisting of silver, zinc,
and copper.
Preferably, the first metal is selected from the group
consisting of zirconium, chromium, and titanium.
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Preferably, the metal compound is metal nitride, and is
selected from the group COIISIStIng of zirconium nitride, chromium
nitride, and titanium nitride.
Preferably, the substrate is made fro~ri a material selected
from the group consisting of copper alloy, zinc: alloy, stainless steel,
ceramics, and plastics.
The first metal sputtered from the first metal target reacts
with a reactive gas, such as nitrogen, methane, or acetylene, in a
sputtering chamber of the sputter (not shown) ao as to form the metal
compound.
Preferably, the sputtering of the first metal target is
conducted at a voltage ranging from 20-SOV, and a current ranging
from 3.5-4.SA, whereas the sputtering of the second metal target is
conducted at a voltage less than 20V, and a. current ranging from
0.3-O.SA. Preferably, a negative biased voltage of greater than -80V
is applied to the substrate 2.
Preferably, the sputtering is conducted at a temperature
ranging from 80-I80°C , and a pressure ranging; from 0.1-20 mTorr for
3-13 minutes.
The present invention will be described in more detail in the
following Example.
Example I
A substrate was subj ected to milling and polishing, followed
by cleaning and drying. The cleaned substrate was then prepared for
deposition of the anti-microbial film using CFUBMS techniques, and
was placed in a sputtering chamber which was filled with nitrogen
and argon gas and which was provided ~avith silver target and
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zirconium target. During the sputtering operation, a negative biased
voltage of -S.OV was applied to the substrate, a positive biased
voltage of less than 20~' (with 0.4A current) was applied to the silver
target, and a positive biased voltage of 30V (vrith 4.0A current) was
S applied to the zirconium target. The sputtering operation was
conducted at a temperature of 1&0°C and a pressure of 1.1 mTorr for
13 minutes so as to form an anti-microbial film (Ag-ZrN) on the
substrate.
The thus formed anti-microbial sanitary ware was then
IO subjected to anti-microbial activity tests in accordance with JI S Z
2801:2000 (Japanese Industry Standard).
The results show that the anti-microbial activity of the thus
formed anti-microbial sanitary ware for escherichia coli is above
99.999 % , and is above 99.9 % for staphylococcus aureus and
1S pseudomonas aeruginosa.
Since escape of the generated plasma in the sputtering
chamber is effectively prevented by using CFUBMS techniques,
which form a continuously closed magnetic field around the substrate,
and since the generated plasma is confined in the continuously closed
20 magnetic field, collision and ionization of molecules in the chamber
are considerably increased, which result in an increase in the
deposition of the material to be deposited on the substrate, which, in
turn, results in an increase in the compactness and bulk density of
the anti-microbial film deposited on the substrate. As ,a consequence,
2S the resistance to corrosion and wearing of the anti-microbial sanitary
ware of this invention is considerably enhanced.
The anti-microbial functions provided by the anti-microbial
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sanitary ware of this invention include one that interferes with the
synthesis of the cell vjall of bacteria, one that damages the cell
membrane of bacteria, and one that interferes with the synthesis of
nucleic acid. As a result of ionization, the metal particles 4 in the
protective Layer 3 of the anti-microbial sanitary ware of this
invention tend to carry positive charges, which results in attraction
of the bacteria, which, in torn, results in damage to the cell
membrane and the enzyme system of the bacteria and the eventual
destruction of the bacteria.
With the invention thus explained, it is apparent that various
modifications and variations can be made without departing from the
spirit of the present invention.
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