[0001] The object of the invention is a new perforated acoustic tile that presents the advantage
of ensuring air pollution removal under visible and ultraviolet light irradiation,
particularly by photocatalysis.
[0002] Acoustic tiles are well known products that are intended to be applied to walls or
ceilings. The acoustic tiles related to the invention are perforated acoustic tile
supports that are covered on their entire rear surface, that is, their non-visible
face, with a nonwoven material. The support may vary and generally is most often in
the form of plaster boards, but also, in certain cases, in the form of metal boards,
wood boards or PVC boards and, more generally, in any type of material.
[0003] The boards of the invention have numerous applications, particularly in public buildings,
train stations, airports, hospitals, nurseries, offices, etc.
[0004] The principle of photocatalysis consisting of destroying various organic pollutants
in air is also a well known principle. In practice, the photocatalytic reaction is
initiated by activating a semi-conductive solid and particularly TiO
2 by UV radiation with a wavelength of less than 380 nm or visible radiation (depending
on the characteristics of the TiO
2), causing electronic changes within the semiconductor and leading to, in the presence
of air, the creation of oxygenated radicals at the surface of the semiconductor. These
radicals attack the organic compounds adsorbed on the semiconductor and, by a succession
of chemical reactions involving water and oxygen from the air, degrade the organic
compounds until the carbon from the carbon chains is completely transformed into carbon
dioxide.
[0005] The idea of conferring photocatalytic properties to acoustic tiles is already known
and, in particular, was described in document
WO-A1-99/51345 of the Applicant. In particular, this document describes the possibility of applying
a TiO
2 - based paint onto the acoustic tile support. Although it is satisfactory in terms
of pollution removal, such a solution prohibits the reworking of the ceiling or wall
inasmuch as the application of a new paint layer on the photocatalytic composition
will destroy its effects. It is thus necessary in such a case to apply a new layer
of photocatalytic paint, which is a particularly costly measure. Considering these
major disadvantages, this solution has never been implemented.
[0006] To get around this problem, a second solution could have been to incorporate the
photocatalytic agent, particularly TiO
2 directly into the support. However, this solution is not completely satisfactory
inasmuch as the photocatalytic effect would only be effective near the perforations
and not on the entire tile surface. In addition, such a solution would be likely to
only relate to plaster tiles and not to wood or metal tiles.
[0007] Document
US-A1-2006/0137276 describes the idea of incorporating zeolite into plaster boards. The zeolite will
have the effect of adsorbing the pollutant, but contrary to what has been indicated,
the zeolite will not be regenerated since zeolite is not a semiconductor. Thus, it
does not act like a photocatalytic agent and does not destroy, in contact with UV
or visible radiation, the previously attached pollutant agents. By operating according
to an adsorption mechanism, the efficacy of zeolite is thus independent from the radiation
to which it is subjected. In other words, even if the zeolite ensures effective pollution
removal, this short-term efficiency is limited due to the saturation phenomenon.
[0008] Document
DE-U1-20102074 describes an acoustic tile consisting of a perforated support to the reverse face
of which a continuous sheet of plastic or aluminum is applied and the front side of
which is provided with a waterproof sheet capable of receiving an 'acoustic treatment'.
The nature of the treatment or the sheet itself is not discussed. In any case, due
to the waterproof character of the sheet, it cannot be a nonwoven support.
[0009] Document
US-A1-2003/0082367 describes a support covered with a photocatalytic composition. Different kinds of
supports (glass, plastic, textile) can be used for different applications (siding,
ceiling, walls). The woven or nonwoven character of the textile is not discussed.
[0010] Document
US-A-5 674 594 discloses an acoustic tile comprising a perforated support wherein one of the surfaces
is covered on its entire surface with a nonwoven material, wherein the nonwoven material
is covered on at least one face by a photocatalytic composition comprising at least
one photocatalyst agent.
[0011] For this reason, the Applicant is focused on the development of an acoustic tile
that removes pollution by the photocatalysis phenomenon, which does not present the
disadvantages of the tiles described in document
WO-A1-99/51345. In particular, the aim of the invention is to provide an acoustic tile that can
be painted without losing its cleaning capacity.
[0012] The Applicant has observed that in a completely surprising manner, the application
of TiO
2 directly onto the nonwoven material of the tile confers a particularly effective
pollution removing activity to said tile.
[0013] In other words, the object of the invention is an acoustic tile comprising a perforated
support in which one of the faces is covered by a nonwoven material over its entire
surface and the face of the nonwoven material facing the perforated support being
covered with a photocatalytic composition.
[0014] The tile is characterized in that at least the face of the nonwoven material facing
the perforated support is covered by a photocatalytic composition comprising at least
one photocatalytic agent.
[0015] In other words, the invention consists of applying the photocatalytic composition
not on the front face of the tile, directly on the support, but on the face of the
nonwoven material arranged onto the rear face of the tile. Such a configuration avoids
the tile reworking problem while ensuring optimal photocatalytic activity, particularly
in offices in daylight or artificial light. In fact, in the two cases, the radiation
spectrum is comprised of UV and visible light allowing the photocatalysis phenomenon
to be activated. In addition, application of the photocatalytic composition on the
sheet material instead of the tile does not affect in any way the acoustic properties
of the tile only existing due to presence of the holes.
[0016] As has already been said, the composition based on at least one photocatalytic agent
is applied on at least one of the material faces.
[0017] In a first embodiment, the composition is applied to the surface of the nonwoven
material facing the support. In practice, the composition is applied at a rate of
2 to 50 g/m
2, advantageously on the order of 4 to 12 g/m
2. Application of the layer is particularly carried out by coating, spraying or an
equivalent method.
[0018] In a second embodiment, the composition is applied to the two faces of the nonwoven
material, in particular by impregnation or an equivalent method. In this hypothesis,
the photocatalytic composition is applied at a rate of 2 to 100 g/m
2, advantageously between 8 and 20 g/m
2.
[0019] As regards the photocatalytic agent-based composition, this contains, in addition
to the photocatalytic agent, at least one binding agent, in particular an inorganic
binding agent.
[0020] The photocatalytic agent is particularly chosen from the group comprising metallic
oxides, alkaline-earth oxides, actinide oxides and rare earth oxides. Advantageously,
the photocatalytic agent is titanium dioxide (TiO
2), preferably anatase. In practice, the titanium dioxide particles have a diameter
of between 10 and 30 nm.
[0021] In a preferred embodiment, the TiO
2 has a specific surface area greater than 225 m
2/g and a particle size on the order of 15 nm. Advantageously, the TiO
2 is the TiO
2 sold by the Kronos company under the brand KRONOS® VLP 7000.
[0022] In a particular embodiment, the photocatalytic composition contains, in addition,
adsorbent particles such as, for example, zeolite. The adsorbent particles such as,
for example, zeolite represent in practice between 1 and 50% by weight of the photocatalytic
composition, advantageously between 5 and 25%.
[0023] As regards the inorganic binder, it is advantageously present in the form of an aqueous
colloidal dispersion of silicon dioxide comprising silica particles able to be bound
to one another after having coated the photocatalytic agent.
[0024] More precisely, the phrase "aqueous colloidal dispersion of silicon dioxide SiO
2", refers to a negatively charged dispersion of amorphous silica particles, with a
high specific surface area, in water. In practice, the specific surface area of the
silica particles is greater than 80 m
2/g, advantageously 100 m
2/g for a particle size of between 25 and 30 nm. Furthermore, it is greater than 300
m
2/g, advantageously 350 m
2/g for a particle size of between 4 and 6 nm. On their surface, the silica particles
present OH groups and OH
- ions, which form a double electric layer, conferring self-bonding properties to said
particles.
[0025] In an advantageous embodiment, the particles of SiO
2 represent from 20 to 50% by weight of the aqueous colloidal dispersion and have a
diameter of between 10 and 50 nm, preferably of between 20 and 30 nm.
[0026] The Applicant has observed that particularly effective results are obtained with
a photocatalytic composition containing from 10 to 60 parts (dry), advantageously
50 dry parts of an aqueous colloidal dispersion of SiO
2 containing between 20 and 50% by weight of SiO
2 with a size of between 10 and 50 nm, advantageously of between 20 and 30 nm, the
complement to 100% being constituted of TiO
2 and, if necessary, of adsorbent particles.
[0027] In a particular embodiment, the complement to 100% is constituted of 25 to 45 parts
of TiO
2 and from 5 to 25 parts of adsorbent particles, such as, in particular, zeolite.
[0028] If necessary and according to demand, the photocatalytic composition may also contain
pigments, particularly black pigments.
[0029] According to another characteristic, the perforated support is advantageously a plaster
support. It may also, nevertheless, be present in the form of a wooden board, a metal
board or a PVC board.
[0030] The nonwoven material designates materials comprising artificial and/or synthetic
and/or natural fibers. The expression 'artificial and/or synthetic fibers' designates
fibers chosen from a group comprising, among artificial fibers, viscose fibers, and
among synthetic fibers, polyester, polypropylene, polyamide, polyacrylic, polyvinyl
alcohol, and polyethylene fibers, alone or in mixture. The expression 'natural fibers'
designates especially cellulose fibers.
[0031] The invention and its resulting advantages will emerge more clearly from the following
embodiments, supported by the attached figures.
Figure 1a and 1b are schematic partial cross sections of two preferred embodiments
of the present invention.
Figure 2 is a schematic representation of a photocatalysis loop.
Figure 3 corresponds to the curve giving the concentration of toluene as a function
of the air treatment time by different types of tile, including the tile of the invention
under UV radiation.
Figure 4 corresponds to the curve giving the concentration of toluene as a function
of the air treatment time by different types of tile, including the tile of the invention
in the absence of any radiation.
Figure 5 corresponds to the curve giving the concentration of toluene as a function
of the air treatment time by different types of tile, including the tile of the invention
under visible radiation.
[0032] Figures 1 a is a schematical partial cross section of an acoustic tile in accordance
with a preferred embodiment of the present invention. The acoustic tile 10 of Fig.
1 a comprises a tile support 12 with holes 14, and a nonwoven material 16 covering
one face of the tile support 12, and being fastened thereon. The surface of the nonwoven
material 16 facing the tile support 12 is coated by a photocatalytic composition 18.
The acoustic tile is, in accordance with a preferred embodiment of the invention,
manufactured such that the tile support 12 is produced, for example from plaster,
and holes 14 being arranged in the tile support. The nonwoven material 16 is manufactured
separately, and a photocatalytic composition 18 is applied on one face of the nonwoven
material 16. The final manufacture of the actual acoustic tile 10 takes place, for
instance, such that an appropriate binder is applied on one face of the tile support
12, and the nonwoven material 16 is laid and pressed on the tile support such that
the photocatalytic composition layer 18 is positioned against the tile support 12.
The acoustic tile of Fig. 1a functions such that the holes 14 of the tile 10 are blinded
by the photocatalytic composition layer 18, whereby the pollutants in the air are
able to reach the photocatalytic composition at the bottoms of the holes and be photocatalytically
degraded such that carbon from the carbon chains is converted into carbon dioxide.
[0033] Fig. 1 b is a schematical partial cross section of an acoustic tile in accordance
with another preferred embodiment of the present invention. The only exception compared
to the acoustic tile of Fig. 1 a can be seen in the structure of the nonwoven material
16. In this embodiment both surfaces of the nonwoven material 16 are coated with photocatalytic
composition 18 and 20. The manufacture of the acoustic tile is similar to the one
discussed above. The function of the acoustic tile 10 is substantially the same, but
now it is possible to utilize the photocatalytic composition 20 arranged on the upper
face (provided that it is a question of an acoustic tile used as a ceiling material)
of the acoustic tile provided that polluted air is allowed to enter the space above
the acoustic tile 10. One option is to arrange the nonwoven material 16 of the acoustic
tile 10 porous such that air is able to pass through the hole 14 and the nonwoven
material 16 to the upper side of the acoustic tile 10. Another option would be to
arrange specific openings in the acoustic tile 10 via which polluted air could enter
the cavity above the acoustic tile, or to arrange corresponding openings to the sides
of the ceiling. In any case, if the photocatalytic composition layer is supposed to
be used, an appropriate light source should be provided in the cavity facing the photocatalytic
composition layer 20 on the upper surface of the acoustic tile.
Example:
[0034] In this example, the pollution removal efficiency of a tile of the invention, in
UV or visible light, is compared to that of an acoustic tile sold by the KNAUF company
under the CLEANEO brand and to standard tiles.
[0035] Figure 2 represents a photocatalysis loop in which the tests are performed. Mainly,
the photocatalysis loop is comprised of a tunnel 1 with a volume equal to 0.1 m
3 in which the pulsed air circulates, coming from the inlet 2 by means of a ventilator
3 with a flow of 150 m
3/h. In addition, the tunnel contains three 24W UV lamps 4 or a lamp emitting in the
visible range positioned near the acoustic tile to be tested 5. Injection of a polluting
agent, in practice toluene, is done at the inlet 6 while the formed carbon dioxide
coming out at end 7 is detected by infrared light by a means 8, the information then
being analyzed by a computer 9.
[0036] The following products are tested:
o CLEANEO Mustev: plaster board sold by KNAUF containing zeolite, according to patent
US-A1-2006/0137276,
o Coated nonwoven 20 g/m2: perforated tile of the invention, in plaster, covered on its rear face (opposite
face of the tile) by a nonwoven material coated with 20 g/m2 of the following photocatalytic composition: 10 g SiO2 (SNOWTEX® 50), 8 g TiO2 of the KRONOS® VLP 7000 brand, 2g of zeolite.
o Standard acoustic tile without nonwoven: standard acoustic tile without photocatalytic
treatment, sold by the LAFARGE company, lacking nonwoven material on the rear face
of the tile,
o Standard acoustic tile with uncoated nonwoven: sold by the LAFARGE company, with
a nonwoven material on the rear face of the tile,
o Coated nonwoven 8 g/m2 + zeolite: perforated tile in plaster according to the invention covered on its rear
face (opposite face of the tile) by a nonwoven material coated with 8 g/m2 of the following photocatalytic composition: 4 g SiO2 (SNOWTEX® 50), 3.2 g TiO2 of the KRONOS® VLP 7000 brand, 0.8 g zeolite.
o Coated nonwoven 8 g/m2 + double zeolite: perforated tile in plaster according to the invention covered on
its rear face (opposite face of the tile) by a nonwoven material coated with 8 g/m2 of the following photocatalytic composition: 4 g SiO2 (SNOWTEX® 50), 2.4 g TiO2 of the KRONOS® VLP 7000 brand, 1.6 g zeolite.
Figure 3:
[0037] This figure shows that under UV irradiation, the tile of the invention is the tile
that degrades toluene most effectively and that generates the most CO
2 by photocatalysis, and that, thanks to the combined action of zeolite, attaches the
pollutant near the TiO
2, which acts by photocatalysis.
[0038] The CLEANEO product also attaches the pollutant thanks to the presence of zeolite.
On the other hand, there is no regeneration of zeolite due to the absence of photocatalytic
agent. The very low generation of CO
2 is probably due to the fact that the plaster boards are not constituted of pure calcium
carbonates and that the board produces a carbonation phenomenon with UV contact. This
cannot be a photocatalysis phenomenon under any circumstances.
[0039] The LAFARGE standard boards/tiles with and without nonwoven material and lacking
the photocatalyst agent and zeolite have an insignificant pollution removal activity.
Figure 4:
[0040] Figure 4 shows that in the absence of UV light, the efficiency of the tile of the
invention is greater than that of the CLEANEO tile. In other words, even in the absence
of light, the pollution removal phenomenon subsists.
Figure 5:
[0041] In this experiment, UV radiation was replaced by visible light whose spectrum was
between 400 and 700 nm.
[0042] As the figure shows, the tile of the invention presents very good pollution removal
efficiency still with the same principle, a combination of the adsorbent effect of
zeolite with the photocatalyst effect of TiO
2.
[0043] From all of these results, it may be deduced that the tile of the invention, with
or without zeolite, may be used in offices in daylight or artificial light, these
two sources comprising both UV (in low proportion) and visible (in high proportion)
radiation.
[0044] The invention and the resulting advantages clearly emerge from the previous description.
In particular, the development of an acoustic board able to ensure removal of pollution
from ambient air, particularly in offices, without any saturation of the pollution
removal sites, should be noted.
1. An acoustic tile (10) comprising a perforated support (12) wherein one of the faces
is covered on its entire surface with a nonwoven material (16), wherein the nonwoven
material (16) is covered on at least one face by a photocatalytic composition (18)
comprising at least one photocatalyst agent,
characterized in that the photocatalyst composition (18) is applied onto the face of the nonwoven material
(16) facing the support (12).
2. The tile (10) according to claim 1, characterized in that the photocatalyst composition (18) is applied onto a face at a rate of 2 to 50 g/m2, advantageously on the order of 4 to 12 g/m2.
3. The tile (10) according to claim 1, characterized in that the photocatalyst composition (18) is applied onto two faces of the material (16).
4. The tile (10) according to claim 3, characterized in that the photocatalyst composition (18) is impregnated to the material (16) at a rate
of 2 to 100 g/m2, advantageously 8 to 20 g/m2.
5. The tile (10) according to any of the previous claims, characterized in that the photocatalyst agent (18) is TiO2 having a specific surface area greater than 225 m2/g and a particle size on the order of 15 nm.
6. The tile (10) according to any of the previous claims, characterized in that the photocatalyst composition (18) furthermore contains adsorbent particles.
7. The tile (10) according to claim 6, characterized in that the adsorbent particles represent between 1 and 50% by weight of the photocatalyst
composition, (18) advantageously between 5 and 25%.
8. The tile (10) according to any of the previous claims, characterized in that the photocatalyst composition (18) contains, as a binding agent, an aqueous colloidal
dispersion of SiO2 containing between 20 and 50% by weight of SiO2 with a size of between 10 and 50 nm, advantageously between 20 and 30 nm.
9. The tile (10) according to claim 1, characterized in that the photocatalyst composition (18) contains from 10 to 60 parts (dry), advantageously
50 dry parts of an aqueous colloidal dispersion of SiO2 containing between 20 and 50% by weight of SiO2 with a size of between 10 and 50 nm, advantageously between 20 and 30 nm, the complement
to 100% being constituted by TiO2 and possibly by adsorbent particles.
10. The tile (10) according to claim 9, characterized in that the complement to 100% is constituted of 25 to 45 parts of TiO2 and 5 to 25 parts of adsorbent particles, such as, in particular, zeolite.
11. The tile (10) according to the previous claim, characterized in that the support (12) is in plaster, wood, metal or PVC.
1. Schallschutzplatte (10), einen perforierten Träger (12) umfassend, wobei eine der
Flächen auf ihrer gesamten Oberfläche mit einem Vliesmaterial (16) bedeckt ist, wobei
das Vliesmaterial (16) auf mindestens einer Fläche mit einer Photokatalysatorzusammensetzung
(18) bedeckt ist, die mindestens einen Photokatalysator umfasst, dadurch gekennzeichnet, dass die Photokatalysatorzusammensetzung (18) auf die Fläche des Vliesmaterials (16) aufgebracht
wird, die dem Träger (12) zugewandt ist.
2. Platte (10) nach Anspruch 1, dadurch gekennzeichnet, dass die Photokatalysatorzusammensetzung (18) mit einer Rate von 2 bis 50 g/m2 auf eine Fläche aufgebracht wird, vorteilhafterweise in der Größenordnung von 4 bis
12 g/m2.
3. Platte (10) nach Anspruch 1, dadurch gekennzeichnet, dass die Photokatalysatorzusammensetzung (18) auf zwei Flächen des Materials (16) aufgebracht
wird.
4. Schallschutzplatte (10) nach Anspruch 3, dadurch gekennzeichnet, dass die Photokatalysatorzusammensetzung (18) mit einer Rate von 2 bis 100 g/m2 auf das Material (16) imprägniert wird, vorteilhafterweise mit 8 bis 20 g/m2.
5. Platte (10) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Photokatalysator (18) TiO2 ist, das eine spezifische Oberfläche von mehr als 225 m2/g und eine Partikelgröße in der Größenordnung von 15 nm aufweist.
6. Platte (10) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Photokatalysatorzusammensetzung (18) des Weiteren adsorbierende Partikeln enthält.
7. Platte (10) nach Anspruch 6, dadurch gekennzeichnet, dass die adsorbierenden Partikeln zu 1 bis 50 Gew.-% der Photokatalysatorzusammensetzung
(18) vorhanden sind, vorteilhafterweise zu 5 und 25 Gew.-%.
8. Platte (10) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Photokatalysatorzusammensetzung (18) als Bindemittel eine wässrige, kolloidale
Dispersion von SiO2 enthält, die zwischen 20 und 50 Gew.-% SiO2 mit einer Größe zwischen 10 und 50 nm enthält, vorteilhafterweise zwischen 20 und
30 nm.
9. Platte (10) nach Anspruch 1, dadurch gekennzeichnet, dass die Photokatalysatorzusammensetzung (18) 10 bis 60 Teile (trocken), vorteilhafterweise
50 Trockenteile, einer wässrigen, kolloidalen Dispersion von SiO2enthält, die zwischen 20 und 50 Gew.-% SiO2 mit einer Größe zwischen 10 und 50 nm enthält, vorteilhafterweise zwischen 20 und
30 nm, wobei die Ergänzung bis 100 % von TiO2 gebildet wird und möglicherweise durch adsorbierende Partikeln.
10. Platte (10) nach Anspruch 9, dadurch gekennzeichnet, dass die Ergänzung bis 100 % von 25 bis 45 Teilen TiO2 und 5 bis 25 Teilen adsorbierender Partikeln, wie beispielsweise Zeolith, gebildet
wird.
11. Platte (10) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Träger (12) aus Gips, Holz, Metall oder PVC besteht.
1. Dalle acoustique (10) dotées d'un support perforé (12), dans laquelle l'une des faces
est couverte sur toute sa surface d'un voile non tissé (16), dans laquelle le voile
non tissé (16) est couverte sur au moins une face par une composition photocatalytique
(18) comprenant au moins un agent photocatalyseur, caractérisée en ce que la composition photocatalytique (18) est appliquée sur la face du voile non tissé
(16) faisant face au support (12).
2. Dalle (10) selon la revendication 1, caractérisée en ce que la composition photocatalytique (18) est appliquée sur une face à un taux de 2 à
50 g/m2, de préférence de l'ordre de 4 à 12 g/m2.
3. Dalle (10) selon la revendication 1, caractérisée en ce que la composition photocatalytique (18) est appliquée sur deux faces du voile (16).
4. Dalle (10) selon la revendication 3, caractérisée en ce que la composition photocatalytique (18) est imprégnée sur le voile (16) à un taux de
2 à 100 g/m2, de préférence de l'ordre de 8 à 20 g/m2.
5. Dalle (10) selon l'une des revendications précédentes, caractérisée en ce que l'agent photocatalyseur (18) est du TiO2 ayant une surface spécifique supérieure à 225 m2/g et une taille de particule de l'ordre de 15 nm.
6. Dalle (10) selon l'une des précédentes revendications, caractérisée en ce que la composition photocatalytique (18) contient en outre des particules adsorbantes.
7. Dalle (10) selon la revendication 6, caractérisée en ce que les particules adsorbantes représentent entre 1 et 50 % en poids de la composition
photocatalytique, (18) de préférence entre 5 et 25 %.
8. Dalle (10) selon l'une des précédentes revendications, caractérisée en ce que la composition photocatalytique (18) contient, comme agent de liaison, une dispersion
colloïdale aqueuse de SiO2 contenant entre 20 et 50 % en poids de SiO2 avec une taille de l'ordre de 10 à 50 nm, de préférence l'ordre de 20 à 30 nm.
9. Dalle (10) selon la revendication 1, caractérisée en ce que la composition photocatalytique (18) contient de 10 à 60 parts (en sec), de préférence
50 parts sèches d'une dispersion colloïdale aqueuse de SiO2 contenant entre 20 et 50 % en poids de SiO2 avec une taille de l'ordre de 10 et 50 nm, de préférence de l'ordre de 20 et 30 nm,
le complément à 100 % étant constitué de TiO2 et éventuellement par des particules adsorbantes.
10. Dalle (10) selon la revendication 9, caractérisée en ce que le complément à 100 % est constitué de 25 à 45 parts de TiO2 et 5 à 25 parts des particules adsorbantes, telles que, en particulier, la zéolithe.
11. Dalle (10) selon la revendication précédente, caractérisée en ce que le support (12) est en plâtre, bois, métal ou PVC.