Preferentially painted textured slats for vertical and horizontal blinds

Extruded material for forming blind slats has at least one textured surface with raised areas and adjacent lower areas. After extrusion and texturing processes, the slat material is passed through a spray painting process applying a substantially thicker coating of paint to the raised areas than to the adjacent lower areas.

CROSS REFERENCE TO A RELATED APPLICATION 
This application is related to a co-pending U.S. patent application, Ser. 
No. 08/970,851, filed Nov. 14, 1997, the disclosure of which is herein 
incorporated by reference. This co-pending application describes a 
multi-layer slat for venetian blinds which is translucent, allowing light 
to shine into a room during the day, together with a coextrusion process 
for making such a slat. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to textured and painted slats for both vertical and 
horizontal window or door blinds, and, more particularly, to a method for 
preferentially coating textured surfaces of such slats with paint, so that 
the peaks or ridges are coated more heavily than surrounding surfaces. 
2. Background Information 
A highly desirable feature of horizontal and vertical blind slats is a 
well-defined, highly-visible surface texture, which differentiates the 
slats from the plain, sterile appearance generally associated with plastic 
blind slats. A conventional method for obtaining such a surface texture is 
through the use of a fabric material. A narrow strip of fabric may itself 
be used as a vertical blind slat, with a metal weight sewn into the strip 
at its bottom end being used to provide a measure of stability for the 
slat, which would otherwise be much too light in weight to hang straight 
or to resist excessive movement in air currents. Alternately, a fabric 
strip may be applied to one or both sides of a thermoplastic slat 
material, such as an extruded PVC strip, which provides weight and 
rigidity. The fabric may present an ordinary textile appearance, or its 
appearance may be enhanced by weaving in fibers of larger diameter and 
differing colors. One problem associated with the use of fabric in these 
ways is a high maintenance requirement caused by dust and dirt lodging in 
the fibers of the porous fabric material, resulting in blinds which are 
particularly difficult to clean. This problem can also result in a 
shortened practical life of the horizontal or vertical blinds, which 
eventually become impossible to clean effectively. 
What is needed is a way to produce a visual effect of a well-defined, 
highly-visible surface texture on the surface of an extruded plastic 
strip, without a necessity for using a porous fabric overlay. 
Translucence is an optical property which is highly desirable in window 
coverings to afford admission of sunlight into a room during the day 
without compromising privacy at night. Popular examples of translucent 
window coverings are found in shades using translucent fabric materials, 
which may be rolled up on a single roll at the top of a window, or which 
may be raised into a pleated or accordion fold as Roman shades. While such 
shades can be lowered to cover a window or raised to reveal a clear view, 
they are limited to presenting a rectangular translucent area; they cannot 
be partially opened to reveal slots through which the outside world may be 
viewed. On the other hand, horizontal or vertical blinds are variable 
louvered structures, which may be fully closed, fully open and drawn back, 
or partly open to present a number of slots through which the outside 
world may be viewed. 
However, blinds are not available with translucent slats. Part of the 
reason for this is caused by the fact that blinds are typically exposed to 
very harsh ultraviolet energy, both from exterior sunlight and from 
interior florescent lighting. Slats for horizontal and vertical blinds are 
often composed of thermoplastic materials, such as PVC (polyvinyl 
chloride), which are available in clear or translucent forms. However, 
such materials are subject to severe discoloration when they are exposed 
to ultraviolet light, unless they include UV stabilizers. These UV 
stabilizers additionally turn a transparent material into a translucent 
material. However, when otherwise transparent PVC is loaded with 
sufficient UV stabilizers to achieve an adequate lifetime in use as a 
blind slat, and when such material is formed into a slat having a 
thickness sufficient to provide the rigidity needed in a blind 
application, the resulting slat is essentially opaque, lacking an ability 
to provide indoor lighting by transmitting outdoor light during daytime. 
Therefore, what is needed is a slat for vertical or horizontal blinds 
having a combination of sufficient thickness for rigidity, sufficient UV 
stabilizers to prevent discoloration, optical translucence, and a well 
defined surface texture, which is clearly visible both under conditions of 
backlighting (as viewed from inside during the day) and front lighting (as 
viewed from inside during the night). 
SUMMARY OF THE INVENTION 
It is a first objective of the present invention to provide a method for 
enhancing textural features in the surface of an opaque blind slat, with 
such enhancement providing a difference in shade or color from surrounding 
areas. 
It is a second objective of the present invention to provide a method for 
enhancing textural features in the surface of a translucent blind slat, 
with such enhancement providing a difference in opacity or color from 
surrounding areas. 
It is a third objective of the present invention to provide a method for 
enhancing textural features in the surface of a translucent blind slat, 
with such enhancement providing a difference in opacity as the slat is 
back lighted and in shade as the slat is front lighted. 
It is a fourth objective of the present invention to provide an inexpensive 
means for painting a texture pattern on an extruded plastic slat. 
It is a fifth objective of the present invention to provide a means for 
painting a textured pattern which is dried without an application of heat 
following the extrusion process. 
In accordance with one aspect of the invention there is provided a slat for 
a blind assembly, with the slat including an elongated section of slat 
material having an inner surface with a texture pattern having raised 
areas and adjacent lower areas, and a partial coating of paint on the 
inner surface, with the partial coating of paint having a substantially 
greater thickness on the raised areas than on the lower areas. 
In accordance with another aspect of the invention, there is provided 
apparatus for producing a visibly enhanced textured surface on slat 
material extruded to form a slat for a blind assembly. This apparatus 
includes a texturing station and a painting station. The texturing station 
has a texturing roll turning in contact with a first surface to the slat 
material and a back-up roll turning in contact with a second surface of 
the slat material, with the second surface being opposite the first 
surface. A peripheral surface of the texturing roll has a surface pattern 
forming, on the first surface of the slat material, a texture pattern with 
raised areas and adjacent lower areas. The painting station, through which 
the slat material is moved after being moved through the texturing 
station, includes a nozzle spraying a mixture of air and paint droplets 
onto the first side of the slat material in a painting process configured 
to apply a substantially thicker coating of paint to the raised areas than 
to the adjacent lower areas.

DETAILED DESCRIPTION 
FIG. 1 is a fragmentary transverse cross-sectional view of a slat 10, made 
in accordance with a first embodiment of the present invention, to include 
a selectively painted inner surface 11 on an innermost layer 12 of a 
number of coextruded layers. The width of slat 10 extends in the direction 
of arrow 13, with its length, extending perpendicularly from the direction 
of arrow 13, being much greater than its width. This slat 10 includes the 
inside layer 12, which is preferably inwardly exposed (into a room) when 
the blind including the slat 10 are closed, and an outside layer 14, which 
is preferably correspondingly outwardly exposed when the blind is closed. 
A first base layer 16 and a second base layer 18 lie between the inside 
layer 12 and the outside layer 14. The inner surface 11 is textured to 
include a number of ridges or peaks 18a, on which paint droplets 18b are 
deposited. The portions 18c of the inner surface 11 between ridges or 
peaks 18a have relatively little paint. 
The inside layer 12, which is 0.08-0.18 mm (0.003-0.007 inch) thick, is 
preferably composed of a UV stabilized PVC material having pearlescent 
pigmentation, such as the material sold by the Geon Company as GEON 87654. 
The outer layer 14, which is 0.13-0.18 mm (0.005-0.007 inch) thick, is 
preferably composed of a semi-transparent UV stabilized PVC, such as GEON 
No. 1260. The first base layer 16, which is 0.25-0.51 mm (0.010-0.020) 
inch thick, is preferably composed of a clear PVC material, such as GEON 
No. 87727-002. The second base layer 18, which is 0.13-0.18 mm 
(0.005-0.007) inch thick, is composed, for example, of a UV stabilized PVC 
material having pearlescent pigmentation, such as GEON No. 87654. The UV 
stabilizing components serve to prevent transmission of ultra-violet rays 
through one layer into another. 
In one version of the present invention, the inside layer 12 includes a 
P.20 to P.40 foaming agent, mixed with the PVC material at a ratio of 3 to 
6 percent. This concentration of foaming agent, being insufficient to 
produce a structural foam product, produces a number of small gas pockets, 
some of which, being near the surface of the slat 10, cause the appearance 
of a matte finish on this surface, in place of the glossy finish generally 
characterizing the surface of a molded or extruded plastic part. The type 
of foaming agent and its concentration are determined according to the 
surface roughness desired in the finished product. In the example of 
FIG.1, the small gas pockets produced by the foaming agent also contribute 
to a cloudy, translucent appearance desired when the slat 10 is 
illuminated with transmitted outdoor light. 
While FIG. 1 shows a portion of the slat 10 adjacent to a longitudinal edge 
18d thereof, it is understood that the opposite longitudinal edge of the 
slat has features similar to those shown in FIG. 1. In particular, the 
inside layer 12 and the outside layer 14 extend around the base layers 16, 
18, overlapping at the rounded edge 18d. This configuration allows a 
relatively high concentration of pigments and UV stabilizers and in the 
layers 12, 14 to protect the base layers 16, 18 from discoloration which 
might otherwise occur if sunlight were allowed to enter these layers 12, 
14 directly along the edge 18d. This feature of the present invention 
provides a significant advantage over the prior-art multilayer extruded 
slats of U.S. Pat. Nos.4,877,077 and 5,119,871, both of which show an 
inner layer exposed along the edges of a slat. This feature is 
particularly significant as a part of the present invention, as it 
facilitates the use of one or more base transparent base layers which 
cannot otherwise be sufficiently protected from discoloration with UV 
exposure over time. 
FIG. 2 is a schematic cross-sectional view of the internal transmission and 
reflection of a light ray 19 in the inside layer 12, which includes a 
number of pearlescent pigment particles 19a. The light ray 19 enters the 
inside layer 12 from the second base layer 18, having travelled through 
the semi-transparent outside layer 14 and the transparent first base layer 
16 (both shown in FIG. 1). Each time the ray 19 strikes a surface of a 
pigment particle 19a, a first portion of the ray is reflected, while a 
remaining second portion is refracted and transmitted. The transmitted 
portion eventually emerges as exiting ray 19b. 
This figure is admittedly a schematic oversimplification of the structure 
of inside layer 12. In a preferred version of the present invention, this 
layer is 0.08 to 0.2 mm (0.003 to 0.007 in.) thick, being composed of a 
transparent PVC material filled with pearlescent pigment particles which, 
being configured particularly to produce a silvery-white appearance when 
viewed by reflected light, are composed of mica particles having a length 
of 5-25 .mu.m and a thickness of 100-500 nm, coated with a layer to 
titanium oxide having a thickness of 40-60 nm. Thus, while the actual 
thickness of the pigment particles 19a, compared to the thickness of the 
layer 12, is much smaller than that shown in the figure, there are many 
more layers of pigment particles 19a within the layer 12 than shown in the 
figure. 
Since the pearlescent pigment particles both transmit and reflect light, 
they are particularly desirable in the application of a layer of material 
being configured for overall translucence. With the alternative use of 
absorptive pigmentation, light rays striking pigment particles are simply 
absorbed. However, the layer of material including pearlescent 
pigmentation must be quite thin to provide a suitable level of 
translucence. 
Referring again to FIG. 1, in its intended use, the slat 10 forms part of a 
horizontal or vertical blind for a window or door, being backlighted 
primarily by sunlight from outdoors during the day and being front lighted 
by artificial light from inside a room during the night. The textured 
inner surface 11 is directed into the room whenever the blind is closed. 
The artificial lighting is on the textured surface 11 is generally 
sufficiently non-uniform to produce shading of the textured features. 
Thus, in the absence of applied paint, under most conditions with front 
lighting, as at night, the textured pattern of inner surface 11 is readily 
apparent due to the shadows produced on the shaded sides of individual 
raised texture features 18a and on portions of the depressed surfaces 18c 
adjacent the shaded sides of individual raised texture features 18a. 
However, in the absence of applied paint, with backlighting from outdoor 
sunlight, the textured pattern tends to disappear. This is because the 
differences in the overall thickness of the slat material 10 due to the 
textured pattern are not sufficient to cause significant changes in light 
transmission. In this regard, it is noted that, in FIG. 1, the texture 
features are greatly exaggerated for clarity. On the other hand, the 
application of paint droplets preferentially on peaks and ridges of the 
texture pattern, in the manner of the present invention, significantly 
enhances the visibility of the texture pattern as illuminated by 
backlight, as light passing through the painted surfaces is attenuated. 
Differences in the tone or shade between the applied paint and the 
unpainted portions of the inner surface 11 can also cause such an 
application of paint droplets to enhance the visibility of the texture 
pattern as illuminated by interior front light. 
FIG. 3 is a longitudinal cross-sectional view of an extrusion die set 20 
used in the production of the slat of FIG. 1. The first base layer 16 is 
formed first, with thermoplastic material 20a being forced from a cavity 
22 in the direction of arrow 24 through a channel 26 in a first die 28. 
The first die 28 also includes an input channel 30 through which 
thermoplastic material 32 is inserted to form second base layer 18. The 
input channel 30 is connected by a narrowed channel 34 to a trough 36 
extending along a portion of the periphery of channel 26 corresponding to 
the peripheral contact between the second base layer 18 and the first base 
layer 16. The shape of second layer 18 is determined by the shape of a 
channel surface 37 extending through a second die 38 and partially through 
a third die 40. Second die 38 also includes an input channel 42 through 
which thermoplastic material 44 is inserted to form outside layer 14. The 
input channel 42 is connected by a narrowed channel 46 to a trough 48 
extending along a portion of the periphery of channel 26 corresponding to 
the peripheral contact between the first base layer 16 and the outside 
layer 14. The shape of outside layer 14 is further determined by the shape 
of a channel surface 50 extending through third die 40 and through a 
fourth die 52. The third die 40 also includes an input channel 54 through 
which thermoplastic material 56 is inserted to form inside layer 12. The 
input channel 54 is connected by a narrowed channel 58 to a trough 60 
extending along a portion of the periphery of the second base layer 18 
corresponding to the extent of peripheral contact between the second base 
layer 18 and the inside layer 12. The shape of inside layer 12 is further 
determined by a channel surface 62 extending through the fourth die 52. 
FIG. 4 is an end elevational view of the die set 20, as viewed in a 
direction opposite that of arrow 24 in FIG. 3. FIG. 4 shows an end of the 
die openings, within which a longitudinally extending rounded edge 18d of 
the slat 10 (shown in FIG. 1) is formed by coextrusion. 
Referring to FIGS. 1 and 4, the channel surfaces 26, which determine the 
shape of first base layer 16, are formed in the shape of a slot with 
rounded ends 64, around which the channel surface 50, forming the shape of 
outside layer 14 partly extends. The trough 48, through which material is 
supplied to form the outside layer 14, also extends partly each slot end 
64. The channel surface 37, which determines the shape of second base 
layer 18, also wraps partly around the slot ends 64. The channel surface 
62, which determines the shape of inside layer 12 wraps around the end 64 
outside the surfaces 37, 50. The trough 60, through which material is 
supplied to form the inside layer 12, also wraps around the end 64. In 
this way, the outer layers 12,14, are formed to overlap and to encapsulate 
the inner layers 16, 18. 
FIG. 5 is a side elevation of a texturing station 66 used to impart a 
texture pattern on an inside surface 68 of slat material 70 being extruded 
from the die set 20. This texturing station 66 includes a metal texturing 
roll 72 and a back-up roll 74 having a rubber coated peripheral surface 
76. The peripheral surface 78 of the texturing roll has a pattern which is 
the inverse of the pattern to formed in the inside surface 68, with ridges 
in the peripheral surface 78 forming grooves in the slat material surface 
68. The rolls 72, 74 are allowed to rotate freely with the motion of the 
slat material 70 in the direction of arrow 24, but are held in engagement 
with the slat material 70 by compression springs 79. After passing between 
the rolls 72, 74, the slat material 70 is pulled through an alignment 
fixture 79a having upstanding oblique surfaces at the edges of the slat 
material 70 for aligning this material 70, a painting station 80 and a 
cooling station 82 onto a conveyer belt (not shown), and is cut to a 
suitable length by a powered knife (not shown) moving with the slat 
material 70 during the cutting process. Within the painting station 80, 
heat from the extrusion process is used to dry the paint. Following the 
painting and drying, the slat material is cooled by cold water being 
pumped through the cooling station 82. 
Referring again to FIGS. 1 and 3, the second base layer 18, which has been 
described above as being composed of a UV stabilized PVC material having 
pearlescent pigmentation, such as GEON No. 87654, is alternatively 
composed of a clear PVC material, such as GEON No. 87727-002. In this way, 
the second base layer 16 is used to provide a significant change in the 
percentage of light transmitted through the slat 10 without reformulating 
the plastic materials and without changing the die set 20. Experiments 
have shown, for example, that the percentage of light transmitted through 
a slat of this type having the second base layer 18 composed of a PVC with 
pearlescent pigmentation is approximately six percent, while the 
percentage of light transmitted through an otherwise similar slat having 
the first base layer 16 composed of a clear PVC is approximately twelve 
percent. While the use of four layers provides this advantage of the 
present invention, it is understood that a version of the present 
invention includes only three layers--an inside layer, and outside layer, 
and a transparent base layer. 
The layered construction of the present invention further allows the use of 
a relatively thick base layer, which is transparent to preserve the 
overall translucency of the slat, while achieving an overall thickness 
sufficient to retain stiffness and strength within the slat. 
While the second base layer 18 is described above as being composed of a 
clear transparent PVC, this layer 18 is alternately composed of a 
pigmented transparent PVC material to provide transmitted light having the 
color of the pigmented material. A slat made in this way retains its 
silver-white appearance when it is illuminated from inside, with light 
reflected from the slat, but changes its effective color to a muted 
version of second layer. A particularly attractive slat has been made in 
this manner using a red pigment within the second base layer 18. 
FIG. 6 is a transverse cross-sectional view of painting station 80, being 
taken as indicated by section lines VI--VI in FIG. 5. 
Referring to FIGS. 5 and 6, within painting station 80, the slat material 
70 is pulled along a longitudinally extending support channel 84 by the 
conveyer system (not shown), being moved through slots 86 in end covers 
88. The painting station 80 also includes side covers 90, but is open at 
the top. A paint spray nozzle 92, held in place by a paint support bracket 
94 extending between the end covers 88, is directed downward at the slat 
material 70 moving through the painting station 80. Paint is supplied to 
the nozzle 92 through a hose 96 from a paint supply container 98. To 
assure the proper flow of paint, the paint supply container 98 is 
preferably pressurized by means of a regulated air supply system (not 
shown). A second hose 100 carries compressed air to the paint spray nozzle 
92. Within the spray nozzle 92, paint from hose 96 is atomized by air from 
hose 100, so that a mixture of air and paint droplets is sprayed downward 
in a generally conical pattern 102. 
The painting station 80 is particularly configured to minimize variations 
in paint coverage along the top surface 104 of the slat material 70, in 
the transverse direction of arrow 106. Such variations, which are be 
caused by radial variations in the density of paint droplets within the 
conical pattern 102 and by the fact that the center of the top surface 104 
passes under the conical pattern 102 for a longer time than the outer 
edges 108 of this surface 104, are minimized by configuring the painting 
station 80 so that the conical pattern 102 overextends the width of the 
slat material 80. Furthermore, a vertical renewable surface 110 is held 
adjacent to each edge of the causing the flow of air and paint to be 
deflected toward the top surface 104, increasing the density of paint near 
each outer edge 108, so that the painting process is more uniform in the 
transverse direction of arrow 106. Each renewable surface 110 is held in 
place within a vertical support plate 112, which is in turn held by a 
number of stand-offs 114 extending inward from the adjacent side cover 90. 
Each renewable surface 110, which may be composed of a sheet of cardboard, 
is inserted downward through a slot 116 formed by a lanced and formed 
strip 118 extending along the top edge of each vertical support plate 112, 
to be held by a pair of hook tabs 120 extending at the bottom of the 
vertical support plate 112. 
The painting station 80 is also configured to prevent overspray paint 
damage to the undersurface 122 of the slat material 70. The passage of air 
under the slat material 70 is prevented by the support channel 84. 
Otherwise, air movement under the slat material 70 could carry paint 
droplets into contact with the undersurface 122. 
Furthermore, the painting station 80 is configured for the removal of paint 
in solid or liquid forms without allowing damage to occur to the slat 
material 70 from such paint. After an excessive amount of paint is 
deposited on the inner sides 124 of the renewable surfaces 110 by direct 
contact with the paint spray pattern 102, these renewable surfaces 110 are 
removed and reversed to present new sides or replaced. During the painting 
process, paint runs or drips from the inner sides 124 of the renewable 
surfaces 110 into gutters 126 extending along the support channel 84. The 
retaining hooks 120 do not interfere in this flow of paint since the are 
spread apart along each vertical support plate 112 far enough lie on 
either side of the paint spray pattern 102. The paint spray pattern 102 
also extends downward through a slot 128 between each renewable surface 
110 and the support channel 84, causing the deposition of paint on the 
vertical surfaces 130 of support channel 84. This paint drips downward 
into the gutters 126 extending below these vertical surfaces 130. Paint 
accumulated in the gutters 126 flows away from the painting station 80 
through drain hoses 132. A spacing plate 134 holds the undersurface 122 of 
the slat material 70 in a spaced-apart relationship with the support 
channel 84 within the portion of the painting station 80 in which the 
paint spraying process occurs. In this way, the transfer of paint from the 
support channel 84 to the undersurface 122 is prevented. The slat material 
70 overextends the spacing plate 134 so that the undersurface 122 does not 
contact any portion of the spacing plate 134 which is not covered by the 
slat 70, either. A cul de sac is thus formed at either side of the spacing 
plate, with a mixture of air and paint droplets being pulled through the 
slot 128 instead of being driven against the exposed portion of the 
undersurface 122. 
A downward flow of air through the painting station 80 is maintained by 
means of an exhaust duct 135 pulling air away from the painting station 80 
through a filter 136, which minimizes the flow of paint into the duct 135. 
The preferential placement of paint droplets on peaks and ridges of the 
textured surface is an observed phenomenon that is believed to be caused 
by a combination of the principles described below in reference to FIGS. 7 
and 8. This phenomenon results in a paint coating which is substantially 
thicker on raised areas of the slat material surface than on adjacent 
lower areas. Operation in accordance with these principles is understood 
not to be necessary for patentability. 
FIG. 7 is an enlarged sectional view of the textured upper surface 104 
having a number of upstanding peaks 142. The air and paint mixture from 
the nozzle 92 (shown in FIG. 6) is directed downward, as indicated by 
arrow 144. However, since the air cannot move through the upper surface 
104, it must flow horizontally outward, as indicated by arrow 146. When 
paint entrained within the air flow comes into contact with the surface 
104, it generally is transferred to the surface 104. This process occurs 
first at the tips of upstanding peaks 142. The outward rate of airflow 
near flat or depressed portions 147 of the surface, as indicated by arrow 
148, is at much lower velocities than the airflow near the peaks, as 
indicted by arrow 146. Since this airflow carries paint, the tips of peaks 
148, upon which more air impinges at a faster rate, are coated with much 
more paint. 
FIG. 8 is an enlarged sectional view of the textured upper surface 104 
having a number of upstanding ridges 150. The air flows outward above the 
ridges, as indicated by arrow 152, with generally stagnate air conditions 
being maintained in the regions 154 between ridges 150. Thus, relatively 
little paint is deposited between the ridges 150. 
Furthermore, the electrostatic forces between paint droplets and the upper 
surface 104 may be responsible for preferential attraction of the paint 
droplets to the points and ridges of the texture pattern. In the process 
of mixing and atomization occurring within the spray nozzle 94, 
triboelectric charging occurs between the paint droplets and the air in 
which they are carried, causing electrostatic charges to be placed on the 
droplets. Also, electrostatic charges are placed in the surfaces of the 
upper surface 104 during the processes of extrusion and of rolling to 
produce the desired texture. Since the upper surface 104 is not flat, the 
electrostatic field above it is not uniform. Fringing fields are directed 
toward the tips of raised features, causing the charged paint droplets to 
be placed preferentially on such tips. 
Since such effects can be overcome by depositing enough paint that paint is 
deposited on all portions of the upper surface 104, the deposition of 
paint must be controlled to achieve the particular visual result desired. 
A metallic clear water-based paint may be used, or the paint may have a 
matte or pearlizing pigment. Good results have been obtained using a 
high-volume, low-pressure nozzle with a 0.5 mm (0.02 in.) diameter orifice 
about 30 cm (12 in.) above the upper surface 104, with a pressure measured 
at the nozzle tip of 3 to 6 psi. The painting process also is dependent on 
the temperature of the surface being painted. Good results have been 
obtained with the paint nozzle 92 being displaced horizontally, in the 
direction of arrow 24 from the texturing rollers 72, 74, through a 
distance of about 76 cm (30 in.), with the temperature of the surface 104 
being about 300 degrees F. 
FIG. 9 is a partially sectional side elevation of an alternate painting 
station 160 used to paint the surface pattern of FIG. 1 on a surface of 
the slat material 70 following extrusion through the dies set 20 of FIG. 3 
and texturing within the texturing station 66 of FIG. 5. In comparison 
with the painting station 80, described above in reference to FIG. 5, this 
alternate painting station 160 is elongated to include two spray painting 
nozzles 92. Each nozzle 92 is connected to its own paint supply container 
98 by a hose 96 and to an air supply (not shown) by means of a hose 100. 
The two nozzles 92 are aligned longitudinally along the slat material 70 
being painted. Other features of the alternate painting station 160 are 
generally as described above in reference to FIGS. 5 and 6. 
This alternative painting station 160 is used to deposit a more even layer 
of paint on the surface of the slat material 70, eliminating some of the 
splattered appearance of paint deposited through the use of the painting 
station 80 of FIG. 5. Even with the alternative painting station 160, 
paint is preferentially applied to peaks and ridges of the texture 
pattern, so that the effects described above are retained. Different 
visual effects can also be achieved by spraying different colors or types 
of paint through the two nozzles 92. Experiments have shown that, in this 
painting station 160, more paint is being applied, so that external 
heating is required to dry the paint as required for handling through the 
apparatus. Thus, a separate blowing heater 164 is added, being directed at 
the slat material 70 between the painting station 160 and the cooling 
station 82. 
FIG. 10 is a fragmentary transverse cross-sectional view of a slat 170, 
made in accordance with a second embodiment of the present invention, to 
include a selectively painted inner surface 172 on an innermost layer 174 
of a number of coextruded layers, and a selectively painted outer surface 
176 on an outermost layer 178 of the coextruded layers. 
FIG. 11 is a partially sectional side elevation of a texturing station 180 
and a painting station 181 used to form the surface patterns of FIG. 10 on 
both surfaces of the slat material 70 being extruded from the die set 20 
of FIG. 3. The texturing station 180 includes a first texturing roll 72 
and a first back-up roll 74, used as described above in reference to FIG. 
5, to place a textured image on the upper surface 104 of the slat material 
70, together with a second texturing roll 182 and a second back-up roll 
184. The second texturing roll 182 has a peripheral surface 185 forming 
the textured surface on the lower surface 122 of the slat material 70. The 
textured pattern being placed on the lower surface 122 may be the same as, 
or different from, the textured pattern placed on the upper surface 104. 
FIG. 12 is a transverse cross-sectional view of the painting station 181, 
taken as indicated by section lines XII--XII in FIG. 11. 
Referring to FIGS. 11 and 12, the painting station 181 includes an upper 
paint spray nozzle 186 directed downward at the upper surface 104 of the 
slat material 70 moving through this station 181 and a lower paint spray 
nozzle 187 directed upward at the lower surface 122 thereof. Each of these 
nozzles 186, 187 is attached within an inner structure 188 by means of a 
nozzle attachment bracket 189. The inner structure 188 is closed at a 
front side 188a, at a rear side 188b, at a top side 188c, and at a bottom 
side 188d, being open at the ends. The inner structure 188 is fastened 
within an outer structure 189 by means of four angle brackets 190, which 
extend between the end covers 191 of the outer structure 190. The outer 
structure 190, which also includes a front cover 192 and a rear cover 193 
is open at the top and includes a filter 194 extending across the bottom, 
where an exhaust duct 196 keeps air moving downward through the outer 
structure 190. Each nozzle 186,187 is supplied with air under pressure 
through a hose 197 and with paint from a supply container 198 through a 
hose 199. 
In the general manner previously described in reference to painting station 
80 of FIGS. 5 and 6, the spray patterns 200, 201 from nozzles 186, 187, 
respectively, overextend the slat material 70, with portions of the flow 
of air and paint being redirected by renewable surfaces 202, in order to 
provide more uniform paint coverage across the width of the slat material 
70, in the transverse direction of arrow 203. Most of the paint deposited 
on the renewable surfaces 202 runs downward, to the bottom side 188d of 
inner structure 188. From this area, paint is carried outside the painting 
station 181 through a hose 204. When an excessive build-up of paint occurs 
on the renewable surfaces 202, they are removed and reversed or replaced, 
being removed and inserted through slots 203 in the upper side 188c of 
inner structure 188. 
The effect of overspray from upper nozzle 186 reaching lower surface 122 of 
slat material 70, or of overspray from lower nozzle 187 reaching upper 
surface 104 thereof, is minimized by placing the nozzles 186, 187 in 
alignment with one another on opposite sides of the slat material 70. 
Since air pressure is introduced from opposite sides of the slat material 
70, there is relatively little air flow around the ends of the slat 
material 70, adjacent the renewable surfaces 202. Nevertheless, this 
embodiment of the present invention is understood to include a paint spray 
station of this general type, having nozzles on opposite sides of the slat 
material 70, which are displaced from one another in the longitudinal 
direction of arrow 24. 
The presence of surfaces contacting the slat material 70 within the paint 
spray station 181 is particularly avoided within the painting station 181, 
since contact with such surfaces could otherwise smear the paint present 
on both sides of the slat material 70. Thus, the slat material 70 travels 
unsupported between the alignment fixture 79a and the cooling station 82, 
a distance of about 91 cm (36 in.). Tension is maintained within the slat 
material 70 by pulling this material with a conveyer belt (not shown) and 
rollers (not shown) engaging the slat material 70 beyond the cooling 
station 82. 
While pairs of paint spray nozzles have been described in detail as being 
located in a longitudinally displaced relationship on the same side of the 
slat material 70 and alternately in an opposed relationship on opposite 
sides of the slat material 70, the present invention is understood to 
include the use of additional nozzles, such as a first pair of nozzles on 
a first side of the slat material 70 and a second pair of nozzles on a 
second side of the slat material, opposite the first side thereof. 
FIG. 13 is a front elevation of a vertical blind assembly having a number 
of the slats 210 hanging from a track system 212, which is of a 
conventional type well know to those skilled in the art of window and door 
coverings. Each slat 210 is of a type described above, either in reference 
to FIG. 1 or FIG. 10 Each slat 210 includes an aperture by which it is 
held on a slat holder (not shown) within the track system 212. 
FIG. 14 is a fragmentary plan view of the vertical blind assembly of 
FIG.13, taken as indicated by section lines XIV--XIV in FIG. 13 to show 
three slats 210. Each slat 210 has an inside surface 214, which has, for 
example, a textured surface formed as described above in reference to FIG. 
5. The transverse sectional shape of the slat 210 is further characterized 
by a curvature of the inside surface 214, such as a convex or "S"-shaped 
curvature, into which the slat material 70 (shown in FIG. 5) is formed 
following the extrusion process, while the material is still warm. 
While FIG. 14 shows each slat having a textured surface on only one side, 
it is understood that the slats may also be of the type described above in 
reference to FIG. 10, having textured surfaces on both sides. 
Referring to FIGS. 13 and 14, the track system 212 causes the slats 210 to 
rotate in unison about vertical axes between an open position in which the 
slats 210 are essentially parallel and a closed position, in which the 
slats 210 cooperate to cover the window or door (not shown) behind them. 
In this closed position, the slats 210 are preferably oriented so that 
their inside surfaces 214 face into the room in which the blind assembly 
is mounted. The track system 212 also causes the slats 210 to move toward 
one another and away from one another. 
FIG. 15 is a cross-sectional end elevation of a horizontal blind assembly 
including a number of slats 216. In the rotated-open position shown, each 
slat 216 rests, with its inside surface 218 facing upward, on a pair of 
transverse support cords 220 extending within a tilt cord loop 222. The 
slats 216 are rotated in unison and lifted to form a stack from the bottom 
by means of a blind mechanism 223, which is of a type well known to those 
skilled in the art of window coverings. The slats 216 are preferably 
rotated from the open position shown by moving an inside side 224 of the 
cord loop 222 downward while an outside side 226 of the cord loop is moved 
upward, so that the inside surfaces 218 of the slats 216 are exposed 
within the room in which the blind assembly is mounted. A lifting bar 228 
is raised by means of two or more lifting cords 230 to raise the slats 216 
in a stack formed from the bottom. 
While the present invention has been described above in terms of the 
application of paint to translucent slat material, to achieve a particular 
advantage when the slat material is backlighted by sunshine during the 
day, it is understood that the processes described above are also applied 
to opaque slat material, forming a texture pattern which is more readily 
visible due to differences in color or shade between the paint and the 
opaque material of the slat. 
While the invention has been described in its preferred form or embodiment 
with some degree of particularity, it is understood that this description 
has been given only by way of example and that numerous changes in the 
details of construction, fabrication and use, including the combination 
and arrangement of parts, may be made without departing from the spirit 
and scope of the invention.