METHOD FOR FORMING A PATTERN ON A SURFACE OF AN ALUMINUM EXTRUSION

METHODE PERMETTANT DE TRACER UN MOTIF SUR UNE SURFACE D'ALUMINIUM EXTRUDEE

English Abstract

A method for forming a pattern on the surface of an
aluminum extrusion comprises the steps of cleaning the
surface of the aluminum extrusion; forming a film on
the cleaned surface of the aluminum extrusion;
providing a base color coating on the surface of the
aluminum extrusion; baking the aluminum extrusion at a
temperature of 150-300 °C; washing the surface of the
aluminum extrusion with an organic solvent; printing
the pattern onto the base color coating by means of a
power-driven metal roller which has the pattern formed
on an external face thereof and which has ink provided
thereon, and a polyurethane roller which contacts
rotatably the external face of the metal roller and the
base color coating of the aluminum extrusion for
transfer printing the pattern from the metal roller to
the base color coating of the aluminum extrusion; and
forming a transparent protective film on the printed
surface of the aluminum extrusion.

Claims

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I CLAIM:
1. A method for forming a pattern on a surface of an
aluminum extrusion, said method comprising the steps
of:
cleaning said surface of said aluminum extrusion by
degreasing, caustic washing and pickling said aluminum
extrusion;
forming a film on said cleaned surface of said
aluminum extrusion;
providing a base color coating on said surface of
said aluminum extrusion;
baking said aluminum extrusion at a temperature of
150-300 °C in order to crosslink and harden said base
color coating;
washing said base color coating on said surface of
said aluminum extrusion with an organic solvent in
order to remove oil stains and dust;
printing said pattern onto said base color coating
on said surface of said aluminum extrusion by means of
a power-driven metal roller which has said pattern
formed on an external face thereof and which has ink
provided thereon, and a polyurethane roller which
contacts rotatably said external face of said metal
roller and said base color coating on said surface of
said aluminum extrusion for transfer printing said
pattern from said metal roller to said base color
coating of said aluminum extrusion; and

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forming a transparent protective film on said
printed surface of said aluminum extrusion.
2. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein said
pattern is in the form of wood grains.
3. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein the
steps of said method are performed continuously on a
conveyor device.
4. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein the
step of providing said base color coating on said
surface of said aluminum extrusion comprises
electrodepositing an electrodeposition coating of a
base color on said surface of said aluminum extrusion
at a temperature of 0-50 °C, the concentration of said
electrodeposition coating being 1-25 wt%.
5. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein the
step of providing said base color coating on said
surface of said aluminum extrusion comprises
electroplating said aluminum extrusion in a mixture
solution of 2-30 g/l stannous sulfate, 5-90 g/l nickel
sulfate and 2-30 g/l sulfuric acid by means of an
alternating current of 5-30 volts.

-9-
6. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein the
step of forming a film on said cleaned surface of said
aluminum extrusion includes the step of electrolyzing
said aluminum extrusion in a sulfuric acid solution in
order to form an oxide film on said surface of said
aluminum extrusion, said sulfuric acid solution
containing sulfuric acid having a concentration of
50-250 g/l, an aluminum ion concentration of 2-50 g/l, an
electrolysis temperature of 10-30 °C, an electrolysis
voltage of 5-25 volts, and an electric current density
of 50-300 A/m2.
7. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein the
step of forming a film on said cleaned surface of said
aluminum extrusion includes the step of dipping said
aluminum extrusion in a chromate solution in order to
form a synthetic film.
8. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 7, wherein the
step of providing a base color coating on said surface
of said aluminum extrusion includes the step of powder-coating
an epoxy resin coating on said surface of said
aluminum extrusion.
9. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 7, wherein the
step of providing a base color coating on said surface

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of said aluminum extrusion includes the step of powder-coating
a polyethylene coating on said surface of said
aluminum extrusion.
10. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein said
ink (2) in the step of printing said pattern onto said
surface of said aluminum extrusion includes an acrylic
coating.
11. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, further
comprising the step of washing said aluminum extrusion
with water before each of the steps of forming said
film on said cleaned surface of said aluminum
extrusion, forming said base color coating on said
surface of said aluminum extrusion, and baking said
aluminum extrusion.
12. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein the
step of forming said transparent protective film on
said surface of said aluminum extrusion includes the
step of applying an ultraviolet coating onto said
printed surface of said aluminum extrusion, and
radiating ultraviolet light onto said ultraviolet
coating in order to harden said ultraviolet coating.
13. The method for forming a pattern on a surface of an
aluminum extrusion as claimed in Claim 1, wherein the
step of forming said transparent protective film on

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said surface of said aluminum extrusion includes the
steps of applying an acrylic coating on said surface of
said aluminum extrusion, and baking said acrylic
coating.

Description

CA 02230942 1998-03-04
METHOD FOR FORMING A PATTERN ON
A SURFACE OF AN ALUMINUM EXTRUSION
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for forming a
pattern on a surface of an aluminum extrusion.
2. Description of the Related Art
Aluminum extrusions are widely used in the
architecture industry. However, since the aluminum
extrusion has a monochromatic surface, the appearance
thereof is dull and lacks aesthetic appeal.
SUMMARY OF THE INVENTION
It is therefore a main object of the present
invention to provide a method for forming a pattern on
the surface of an aluminum extrusion in order to
improve the appearance thereof.
According to the present invention, the method for
forming a pattern on the surface of an aluminum
extrusion comprises the steps of:
cleaning the surface of the aluminum extrusion by
degreasing, caustic washing and pickling the aluminum
extrusion;
forming a film on the cleaned surface of the
aluminum extrusion;
providing a base color coating on the surface of
the aluminum extrusion;

CA 02230942 1998-03-04
baking the aluminum extrusion at a temperature of
150-300 °C in order to crosslink and harden the base
color coating;
washing the base color coating with an organic
solvent in order to remove oil stains and dust;
printing the pattern onto base color coating of the
aluminum extrusion by means of a power-driven metal
roller which has the pattern formed on an external face
thereof and which has ink provided thereon, and a
polyurethane roller which contacts rotatably the
external face of the metal roller and the base color
coating of the aluminum extrusion for transfer printing
the pattern from the metal roller to the base color
coating of the aluminum extrusion; and
forming a transparent protective film on the
printed surface of the aluminum extrusion.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of this invention
will become apparent in the following detailed
description of the preferred embodiments of this
invention with reference to the accompanying drawings,
in which:
Figure 1 is a flow diagram showing the method for
forming a pattern on a surface of an aluminum extrusion
according to the present invention; and

CA 02230942 1998-03-04
Figure 2 is a schematic view illustrating the
equipment for printing the pattern on the surface of an
aluminum extrusion according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figure 1, a preferred embodiment of
the method for forming a pattern on a surface of an
aluminum extrusion in accordance with the present
invention is shown to comprise the steps of cleaning,
film-forming, providing a base color coating, baking,
washing, pattern-printing, and forming a protective
film. In this embodiment, the pattern is in the form
wood grains. The steps of the method for forming the
pattern on the surface of the aluminum extrusion may be
carried out right after the steps of the method for
forming the aluminum extrusion in order to form and
process the aluminum extrusion continuously. In
addition; the method of the present invention can be
performed a continuously on a conveyor device.
The cleaning step includes the step of dipping
sequentially the aluminum extrusion into washing tanks
which contain a surface-active agent, 1-500 of sodium
hydroxide and 15-30% of nitric acid, respectively, in
order to remove grease from the surface of the aluminum
extrusion.
The cleaned aluminum extrusion is electrolyzed in a
sulfuric acid solution in order to form an oxide film.
The sulfuric acid solution contains sulfuric acid

CA 02230942 1998-03-04
having a concentration of 50-250 g/1, an aluminum ion
concentration of 2-50 g/1, an electrolysis temperature
of 10-30 °C, an electrolysis voltage of 5-25 volts, and
an electric current density of 50-300 A/m2. The
function of the oxide film is to provide a weather-
proof effect to the aluminum extrusion.
A base color coating is provided on the film at the
surface of the aluminum extrusion by electrodepositing
an acrylic electrodeposition coating of a base color on
the surface of the aluminum extrusion at a temperature
of 0-50 °C. The concentration of the electrodeposition
coating is 1-25 wt%. The base color coating can
improve the appearance of the aluminum extrusion and
protect the aluminum extrusion.
The aluminum extrusion is then baked at a
temperature of 150-300 °C in order to crosslink and
harden the base color coating.
Next, the base color coating of the aluminum
extrusion is washed by an organic solvent in order to
remove oil stains and dust therefrom.
After the base color coating has been washed with
the organic solvent, a predetermined pattern, such as
wood grains, is printed onto base color coating of the
aluminum extrusion by means of the printing device, as
best illustrated in Figure 2. The printing device has
a power-driven metal roller 1 which has the wood grain
pattern formed on an external face 11 thereof and which

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has ink 2 (or hn acrylic coating) provided thereon by
means of an ink application roller 5. A scraper 4 is
provided adjacent to the metal roller 1 in order to
remove excess ink from the external face ,11 of the
metal roller 1. The printing device further ha$ a
polyurethane roller 3 which contacts rotatably the
extex'nal face 11 of the metal roller 1 and base color
coating of the aluminum extrusion for transfer printing
the wood grain pattern ~x-om the metal roller 1 onto the
base color coating of the aluminum extrusion_
Finally, a transparent protective film is formed on
the printed surface: of the aluminum extrusion by
applying an ultraviolet coating onto the printed
surface of the aluminum extrusion and radiating
ultraviolet light onto the ultraviolet coating in order
to harden the ultraviolet coating.
In addition, the method for forming a pattern on
the surface of the aluminum extrusion further comp~c-ises
the step of washing the aluminum extrusion with water
zp before Bach of the steps of forming the film on the
cleaned surface of the aluminum extrusion, forming the
base color coating on the surface of the aluminum
extrusion, and baking aluminum extrusion in order to
clean positively the :surface of the aluminum extrusion_
2g Alternatively, the base color coating may be
px-ovided onto the surface of the a~.uminum extrusion by
electroplating the aluminum extrusion in a mixture

CA 02230942 1998-03-04
solution of 2-30 g/1 stannous sulfate, 5-90 g/1 nickel
sulfate and 2-30 g/1 sulfuric acid by means of an
alternating current of 5-30 volts.
Furthermore, a synthetic film may be formed on
the cleaned surface of the aluminum extrusion instead
of the oxide film by dipping the aluminum extrusion in
a chromate solution, and the base color coating may be
provided onto the surface of the aluminum extrusion by
powder-coating an epoxy resin or polyethylene coating
on the surface of the aluminum extrusion.
Moreover, the transparent protective film may be
formed on the printed surface of the aluminum extrusion
by applying an acrylic coating on the surface of the
aluminum extrusion, and baking the acrylic coating.
Furthermore, in the step of forming the pattern on
the surface of the aluminum extrusion, the printing
device may comprise a plurality of metal rollers and
polyurethane rollers for printing a plurality of sets
of patterns onto the surface of the aluminum extrusion.
The metal and polyurethane rollers may be disposed
around the entire surface of the aluminum extrusion in
order to improve the printing efficiency.
While this invention thus explained, it is
apparent that numerous modifications and variations can
be made without departing from the scope and spirit of
this invention. It is intended that this invention be
limited only as indicated in the appended claims.