Note: Descriptions are shown in the official language in which they were submitted.
CA 02241069 1998-06-19
15736-032
WEB-SHAPED SEMIFINISHED PRODUCT, IN PARTICULARWALL
COVERING PLASTER, AND PROCESS FOR PRODUCING THE SAME
The present invention concerns a semifiniched web, specifically a plaster-
impregnated wall covering, and a method of manufacturing it. At least one side of a flat
5 and at least to some extent flexible base is coated with a coating that will be flexible
subsequent to hardening.
A semifini ched web of this type is known from German Patent No. 3,111,899 A,
which describes coating a glass-fiber non-woven fabric weighing 50 g/m2 with a sealant
weighing 150 g/m2 that penetrates at least part-way into the fabric.
The sealant comprises:
18 to 20 % di-isodecyl phth~l~te;
0.5 to 1 % zinc stabilizer;
8 to 10 % ethyl glycol;
30 to 35 % powdered polyvinyl chloride; and
20 to 25 % talc.
Plastic weighing 200 g/m2 is then applied to the sealant and expanded at
conventional temperatures. The layer of expanded plastic can be provided with a
decorative pattern.
Mineral substances like talc, calcium carbonate, and titanium oxide and tempering
20 materials like ultraviolet absorbers and PV stabilizers are intended to ensure a certain level
of weathering resistance. The elasticity of the sealant and plastic are admittedly ensured by
softeners, which displace the thermoplastic range to lower temperatures. To ensure the
resistance of the plastic, however, requires minimi7~tion of the wall-resistant softeners and
of their proportions. Coating the fabric, however, is costly and consumes considerable
25 material. This semifini.ched web is also too thick and too heavy.
A wall covering with a base of expanded plastic covered with paper or plastic with
a layer of barite filler between them is known from German Patent No. B 1,150,941.
CA 02241069 1998-06-19
15736-032
One drawback to this wall covering is that it results in a wall of two sheets, which,
although it does provided insulation against noise, is too thick and too heavy. The
thickness decreases flexibility and makes it difficult to unroll and handle.
A wall-covering sheet or board is known from German Patent No. U 7,931,745
Ul. It is made of extruded polystyrene foam. The sheet is 1 to 3 mm thick and up to 1200
mm wide and the board 2.5 to 6 mm thick and either 800 x 1250 or 800 x 1200 in size. A
layer contail~ g an adhesion promoter is applied to one side. The a&esion promoter
comprises diluted dispersion a&esives that attach the sheet or board to the wall. When
between 50 and 100 g/m3 are applied, flame retardants must also be included to decrease
fl~mm~bility.
European Patent No. A 78,404 discloses an insulated outer-wall covering board.
It comprises insulating board with a layer of plaster. The plaster is composed of granulated
or powdered insulation, woven glass fiber covered with a sheet of plastic, and a cement
binder of plastic dispersed in water.
l S The drawback to this wall covering is a high strength that makes it very rigid.
A l~min~ted board and a method of m~mlfacturing it is known, finally, from
German Patent No. C 4,239,269. It comprises an expanded-plastic core with at least one
side coated with a curing-plastic mortar, embedded with woven glass fiber. The board is
manufactured by applying the mortar to the expanded plastic and forcing the continuous
20 web of glass fiber into it. Excess mortar is then scraped off with a doctor and allowed to
accumulate. How much mortar is employed is regulated by detecting the accumulation.
The still moist mortar and its reinforcement, and the core as well if necessary, are then
trimmed, to size and the mortar allowed to dry and cure.
This laminated board and its method of manufacture have been proven practical.
25 Since, however, the expanded-plastic core is at least 30 mm thick and the mortar both rigid
and more than 0.5 mm thick, the board, even at its thinnest is not pliant enough to be
handled as conveniently as even a thin slab of stone.
One object of the present invention is accordingly an improved semifini.ched weband specifically a plaster-impregnated wall covering of the aforesaid type that will act
CA 02241069 1998-06-19
15736-032
externally like a layer of plaster and will be easier to m~nllf~cture and handle. Another
object is a simple and cost-effective method of m~n~lf~.turing such a semifinished web or
plaster-impregnated wall covering.
The first object is attained in accordance with the present invention in a
semifini~hed web or plaster-impregnated wall covering of the aforesaid type by the
characteristics recited in the body of claim 1.
The present invention has many advantages. The elastic layer or layers of softener
applied to the flexible base result in a web that can, like wallpaper, not only be unrolled but
slit, sheared, and attached. The rolls can be trimmed into smooth strips that extend from
the top to the bottom of the wall being covered. Ceilings can also be similarly covered,
primarily because of the elastic layer of mineral-loaded softener. The coating will set as it
dries but will not harden like a conventionally rigid mortar in that it is a blend of mineral
substances and dispersed plastic. "Dispersed plastic" is an overall term for a dispersion of
freely distributed plastics in a usually aqueous medium. Most of the dispersing occurs in
l S the liquid phase. Once the dispersion has cured, the individual mineral particles are
encapsulated and connected by bridges. This provides the layer of soft mineral-loaded
plastic with flexibility and results in the aforesaid advantageous properties of rollability,
convenient h~n(lling, etc.
The wall covering can be as wide as conventional wallpaper, or between 400 and
1250 mm. When in the form of a board, the covering can measure between 300 mm2 and
1250 x 2500 mm. The finished size depends on the particular application. Attaching such
a covering in the form of a sheet or board to a wall ceiling will also provide heat insulation.
The surface will be very smooth and will resemble plaster. The "plaster" can be smooth or
textured. The structure will leave the joints between adjacent sections invisible. Any
constantly working gaps in the wall or wall surface can accordingly be effectively covered.
The covering can be either permeable or impermeable to water, depending on the
application.
The base can be a sheet of plastic, paper, or fabric.
CA 02241069 1998-06-19
15736-032
The particular type of sheet employed depends on its thickness and permeability.Permeability in particular constitutes a parameter for perforations in the sheet. These
perforations can be stamped out of water-permeable or water-impermeable sheet. They can
also be constituted by the interstices in a loose-woven fabric.
The most appropl;ate fabrics are non-wovens. Non-wovens are made of loose
filaments of glass, polypropylene, polyester, thread, paper, viscose, or other natural or
artificial fibers, generally bonded together by inherent adhesion and depending on how
they are m~nlJf~ctured. The individual fibers can either have a preferred orientation
(parallel or transverse) or not (swirled).
The non-wovens can be mechanically reinforced by needling, meshing, or
swirling. They can also be reinforced by fastening the fibers together with liquid binders
(dispersions of acrylate and polymer, SBR and NBR, or polyester and polyurethane), by
fusion, or by the dissolution of what are called binding fibers blended in during
m~nl~f~cture.
When non-wovens are consolidated, the surfaces of the fibers are etched with
appLopliate chemicals and either pressed together or fused at a high temperature.
It has surprisingly been discovered that boards of spin-woven polyester (PES)
fibers are applopliate for such plaster-impregnated wall coverings. Such products are not
toxic and contain no preparations. They can be processed at up to 300 ~ C. They are
porous enough to permit the permeation of air and hence of the coating.
The recipe for the artificial-resin mortar employed for such a coating is important.
The liquid portions have essentially two constituents. One component can be an elasticizer
that accounts for 10 to 45 % and preferably 22 % of the mortar's overall mass. The
elasticizer can contain at least 80 to 90 % by weight of a dispersed copolymer of butyl
acrylate and styrene, preferably 57 % in water, and 0.5 to 2 % of dispersed paraffin,
preferably 30 % in water. The other component can comprise 3 to 4 and preferably 3.7 %
of all the water in the mortar by weight. The first elasticizer component renders the cured
mortar elastic and ductile, allowing the finished plaster-impregnated wall covering to be
handled like wallpaper, in that it can be unrolled, trimmed, stretched, cemented, and torn.
CA 02241069 1998-06-19
15736-032
The second elasticizer component, which can be water, renders the mortar fluid, prevents' it
from curing too rapidly, and accordingly facilitates its handling. The mortar can contain 1
to 15 and preferably 3.7 % of the second elasticizer component by weight.
The artificial-resin mortar can contain:
% by volume Components
40 - 95 aqueous binder
5 - 50 latent aqueous binder
0 - 20 filler
0.1 - 5 hydrophobing agent
0- 10 silicate
0 - 10 dispersant
0 - 5O liquefier
1 - 3 stabilizer
in powdered forrn.
To these components can be added:
% by volume Components
0 - 5 reaction retardant
0 - 5 setting accelerator
0 - 3 thickener
0 - 5 foamer
The aforesaid formulations make it possible to provided the plaster-impregnated
wall covering's artificial-resin mortar with its processing properties and characteristic look.
The dispersant, liquefier, and stabilizer consist of a plastic, specifically a vinyl
acetate.
Coloring can be blended either directly into the powder or later into the mixed
artificial-resin mortar. The coloring can be a light-colored pigment, especially a
conventional white. The layer of mortar can be colored while the pigment is being added.
15 Since cement is usually dark gray after setting, the color of the layer of mortar can be
CA 02241069 1998-06-19
15736-032
lightened by adding even enough white coloring or pigments to render it white or almost
white. The colorings can simultaneously supplement or improve the mineral substances or
plastics in the mixture. Once such a colored mortar is hard, it will need only one coat of
paint. The light-colored and almost white layer of mortar will also show through the paint
5 considerably and improve its appearance.
A woven support can also be embedded in one of the coats of artificial-resin
mortar. Such a support can be a thin tissue of slender fibers. Such a layer will make the
surfaces as easy to handle and process as those of l~min~ted board, and they can be
plastered, wallpapered, or covered with fabric.
One or more heating devices, electric wires for example, can be applied to or
embedded in one of the coats of artificial-resin mortar. Such wires can be applied to an
outer surface and pressed into the mortar.
The artificial-resin mortar can be sprayed or brushed onto the surface of the web.
Such an approach can produce a very thin layer, only 0.01 to 0.1 thick. A two-component
15 mortar can also be rolled or painted on. The particular mode of application depends on
how thick the layer of mortar is intended to be.
The other object of the present invention is a method of m~nllf~cturing such a
semifinished web or plaster-impregnated wall covering whereby:
A) a flat and at least to some extent flexible base is advanced over a rotating
20 flattener at a speed of 1 to 15 m/min,
B) a mineral-loaded dispersion of plastic is applied to one of the sides of the base
from a combination mixer and tank at a spread of 100 to 350 mm,
C) the mineral-loaded dispersion of plastic is scraped into a smooth coat with adoctor,
D) the base, accordingly coated on at least one side, is forwarded at 1 to 15 m/mm
through a drying section by an air-permeable linked-bar conveyor belt to set the dispersion,
and
E) the resulting semifini~hed web is kept ready in a storage device.
CA 02241069 1998-06-19
15736-032
The method in accordance with the present invention has several advantages.
Such a semifini~hed web or plaster-impregnated wall covering is easy to m~nuf~cture
continuously. It is significant that the dispersion is applied at a spread of 10 to 350 mm.
Spread is employed in the construction industry as a measure of the flow or viscosity of a
5 mortar. Wall mortar for example has a spread of less than 120 mm. It has surprisingly
been discovered that, when non-wovens with an air permeability of 4 to 6000 l/m2 sec are
employed as bases, an artificial-resin mortar with an elasticizing component in the form of
a mineral-loaded dispersion of plastic will have a spread of 160 to 210 mm. A mortar with
such a spread will spread more easily and flatter over the surface of the non-woven as well
10 as penetrate into its pores as intended. With the base moving at the discovered optimum of
1 to 15 and preferably 5 m/min, the mortar's depth of penetration and extent of permeation
can be regulated. Removing the excess mortar with the doctor to a desired depth precisely
establishes the layer's thickness. The mortar will set at the same forward speed as the
coating, ensuring a steady forward motion on the part of the base. The temperature and
15 length of the drying section ensure a predictable drying rate and hence industrial-scale
m~nuf~cture. The air-permeable conveyor ensures all-around drying and hence rapid and
complete setting of the mixture. Storing the final semifini~hed web or plaster-impregnated
wall covering keeps it ready for shipment. Essential to the present invention is that the
method known from German Patent No. A 4,239,269 is partly exploited for the new and
20 improved method. The fundamental steps of the method allow the m~nllf~cture of the final
plaster-impregnated wall covering product as intended.
The spread can be monitored continuously or at intervals of 10 minlltes or of one
or three hours during step B). A measured volume of liquid component can be fed to the
tank and removed at a specific rate to maintain the spread within specified limits. This
25 measure will ensure plaster-impregnated wall coverings and surfaces thereof of constant
quality.
Coloring can also be added to the mineral-loaded dispersion of plastic during the
same step. The coloring will conveniently diffuse and dissolve as the lni~ e is prepared.
The accumulating mineral substances and the dispersion of plastic can be detected
30 with a sensor in the following step C) and exploited as a parameter to regulate how much
of the mixture to introduce.
CA 02241069 1998-06-19
15736-032
The signal that represents the accl~m~ ting mortar and the signal that represents
the spread can be forwarded to controls. The controls can be computerized. The output
signal can be employed to regulate the supply of liquid and mixture.
The doctoring off of the excess mortar can be exploited to provide the still moist
5 layer with a texture. The texture need not be that of the doctor. Generally, however, the
doctor will leave the moist layer smooth and flat. Between steps C) and D) on the other
hand, the moist layer can be provided with a specific texture by means of a texturing
device. Such textures can imitate those of plaster, wallpaper, etc.
The mineral-loaded soft plastic layer can be cured with infrared radiation during
10 step D). It has surprisingly been discovered that such radiation is especially useful fort
accelerating setting subsequent to coating. The radiation will cause the mixture to set so
rapidly and effectively that it will be resistant to pressure in as soon as 5 to 25 minutes.
The bonding of the mineral-loaded dispersion of plastic can be promoted by
flushing with air from below. This is done by flushing with warm air the side that is not
15 actively coated. The process can even be accelerated with infrared radiation. It is useful
for the coated base to be dried from both above and below with infrared radiation or hot air
to control the bonding rate.
In step E) the semifini.~hed web can either be rolled up or trimmed to length. How
the resulting product is to be stored depends on how it is to be shipped and handled.
It is of essence to the present invention, however, that rolling the semifini~hed
web up will at least advance the base, especially where it is coated on one side, and hence
adjust and regulate the speed of advance. Since rolling up the final product will
conveniently stretch the unllill~llled base, the speed can be controlled very much as
intended.
One embodiment of the present invention will now be specified with reference to
the accompanying drawing, wherein:
Figure 1 is a schematic illustration of part of a plaster-impregnated wall covering
m~nllf~ctured from a web of non-woven;
CA 02241069 1998-06-19
15736-032
Figure 2a is a section through part of the plaster-impregnated wall covering
illustrated n Figure 1 along the line IIA-IIA;
Figure 2b is a larger-scale detail of the area IIB in Figure 2a;
Figure 3 is a schematic side view of a device for carrying out the method of
5 manufacturing the plaster-impregnated wall covering illustrated in Figures 1 through 2b;
Figure 4 is a schematic top view of the device illustrated in Figure 3;
Figures 5a and 5b illustrate instruments for me~curing the spread of a mortar inaccordance with DIN 1045; and
Figure 6 is a schematic perspective view of part of an interior wall covered with a
10 heat-insulating wall covering.
Figure 1 illustrates a web 2 for a plaster-impregnated wall covering 100 or 101.Web 2 is made of spin-woven polyester fibers, specifically polyethylene terephth~ te with
a thermoplastic polymer added to it. The web has pores 22 and fibers 23.
It has surprisingly been discovered that a spin-woven web 2 with the following
15 specifications is the most practical for m:~nuf~cturing a plaster-impregnated wall covering
100 or 101.
Mass per unite of area: 57 < 64 < 70 g/m2
Connective portion: approx. 30 %
Thickness: approx. 0.20 m
Tensile strength, longitudinal: 190 < 200 N per 5 cm
Tensile strength, transverse: 130 < 140 N per 5 cm
Type of glass: E-Glass
Fiber diameter: 13.5 11 -
Fiber length: 18 mm
Air permeability: 5000 l/m2 s
These characteristics can vary with a tolerance of ~10 %. The web 2 can be rolled
up in lengths of approximately 2500 m to a diameter of approximately 77 cm.
CA 02241069 1998-06-19
15736-032
Of special significance to the further handling of the particular web 2 employedare its weight per unit area, its titer, and its permeability to air. "Titer" is a term employed
in the textile industry as a measure of fiber and filament fineness, their weight per length,
that is, and is expressed in terms of "tex". A titer of 1 to 10 Dtex and preferably of 4 to 6
5 Dtex can be employed instead of the weight per unit of area. In describing the tolerance
range for either g/m2 or Dtex, either can be converted to represent the lowest and
upperrnost threshold.
Air permeability is a measure of the porosity of web 2. Pores 22 extend all the
way through from one side 21 to the other side 24.
An artificial-resin mortar 11 is applied to the aforesaid woven web 2.
The composition of mortar 11 will now be specified in terms of parts A), B), andC).
A) 1000 g (74.1 % by weight) of powdered components in the form of very fine-
grain cement and additives, specifically:
% by volume Component
40 - 95 aqueous binders
5 - 50 latent aqueous binders
0 - 20 filler
0.1 - 5 hydrophobing agent
0 - 10 silicate
0 - 10 dispersant
0 - 5 liquefier
o - 3 stabilizer
plus optionally:
0 - 5 reaction retardant
0 - 5 setting accelerator
0 - 3 thickener
0 - 5 foamer.
CA 02241069 1998-06-19
15736-032
B) 300 g (22.2 % by weight) of elasticizer, specifically 80-90 % by weight of a 57
% dispersion of a copolyrner of butyl acrylate and styrene in water, and
0.8 - 2 % of a 30 % dispersion of paraffin in water.
Elasticizers of similar composition are known. They can be employed to
elasticize cement, lime, and plaster products to make them ductile. Essential to the present
invention is that the specific elasticizers be more effective then known elasticizers and that
the addition of 300 to 1000 g of powdered component will have a positive effect on the
h:~n(lling and processing of mortar 11 and of the wall covering 100 or 101 that employs it.
C) 50 g (3 .7 % by weight) of water.
Adding this amount of water improves the h~n(llin~ properties of the mixture of
components A) and B). Coloring can also be added to the mixture. Any coloring can be
employed. A very dark mortar can be advantageously be lightened, however, by adding
white until it is entirely or almost white. One measure of the mixture's processing
15 properties is spread A, which will be specified later herein.
The foregoing specifications must be skillfully observed. They may deviate ~ 25
% without depriving the accordingly mixed artificial-resin mortar 11 of any essential
properties. The specified mixture is intended for the hereintofore specified non-woven web
2.
An artificial-resin mortar of the aforesaid composition is, once has been well
blended, applied to non-woven web 2. Since the web is part of a 2500 m roll, mortar 11
can be applied continuously to it.
Due to the aforesaid specifications for web 2 and on the flow capacity of an
artificial-resin mortar 11 of the aforesaid composition, it has surprisingly been discovered
that, when the mortar is applied to side 21, not only that side but the other side, side 24, as
well will also be coated. As side 21 is coated, that is, mortar 11 will penetrate through
pores 22 and at least partly surround fibers 23 as illustrated in Figure 2b.
CA 02241069 1998-06-19
15736-032
How much artificial-resin mortar 11 is to be applied to side 21 is determined in a
continuous process by how fast and how much mortar is available. The penetration of the
pores 22 and the occurrence of mortar on side 24 will procéed at the same rate. The
thickness of the coating can be affected by the number of applications. How the mortar is
5 applied will also allow the creation of surface textures that will assist the processing of
wall coverings 100 or 101 and render the joints almost invisible when the covering is
attached to the wall.
Non-woven web 2 has a "filtering" effect that, when artificial-resin mortar 11 is
applied to only one side 21, essentially retains the coarser particles of the mortar on that
10 side while allowing the finer ones, especially the resinous particles, to penetrate to other
side 24. The slenderness of pores 22 and the screening of the powder components,especially the cement and sand-sized grains, determines what solids can penetrate to the
other side. The proportion of water in the three-component mortar 11 increases it brushing
capacity and allows the coating to be smoothed on both sides.
As artificial-resin mortar 11 dries, it creates a flexible coat 1 on side 21 and a
flexible layer 3 of impregnation at least in pores 22, possibly along with another coat 1' on
side 24. Layer 3 constitutes a series of "points" over wall covering 100 or 101 that bond to
the mortar and connect flexible coats 1 and 1' together. In other words, non-woven web 2
will be at least to some extent both surrounded by and saturated with the hardened mortar.
Figures 3 and 4 illustrate a device for manufacturing wall covering 100 or 101.
A roll 41 of non-woven is mounted at the entrance to the device, and a web 2
unrolled from it over web-advance controls 42. Web-advance controls 42 constitute a
rotating cylinder 43 secured in a frame 44. It is essential to the present invention that
cylinder 43 can rotate freely around its axis such as to ensure that web 2 will travel straight
along a flat surface 48. Before arriving at surface 48, however, web 2 travels over feed
cylinders 45 and 46. The web is then laid against the surface by a pressure-application
cylinder 47.
Flat surface 48 is constituted by a continuous and liquid-tight conveyor belt 49that travels around rollers 50 and 51, one of which is powered. Web 2 advances at a speed
CA 02241069 1998-06-19
15736-032
v of between 1 and 15 and preferably 5 m/min, and, since conveyor belt 49 travels at the
same speed, flat surface 48 moves along with the web.
An artificial-resin mortar 11 is applied to web 2 from a combination mixer and
tank 52. A doctor 53 removes excess mortar and establishes an average thickness for what
will be a flexible coat 1 of mortar. The doctoring produces an accumulation 13 of mortar
upstream of doctor 53. Accumulation 13 is measured with a sensor and exploited as a
parameter for how much mortar 11 will be supplied.
Not only the accumulation 13 of mortar 11, however, but also its spread A is
measured in accordance with DIN 1045 by the means illustrated in Figures 5a and 5b.
10 These means comprise a glass plate 71 and a Vickert ring 75. Glass plate 71 is square,
with edges 72 and 73 300 mm long and a thickness 74 of 5 mm. A Vickert ring 75 is an
instrument in the form of a hollow truncated cone with an upper inside diameter 76 of 70
mm and a lower inside diameter 77 of 80 mm. The ring has a thickness 78 of 2.5 mm and
an altitude 79 of 40 mm.
How spread A is determined will now be specified. Vickert ring 75 is positioned
at the center of glass plate 71. Enough mortar 11 is introduced from tank 52 to entirely
occupy the ring. The ring is then lifted and the mortar allowed to spread over the plate.
The spread A of mortar 11 is considered as ranging from a minim~l diameter of 150 to 180
and preferably 170 at a height of 5 to 10 and preferably 6 to 8 mm to a maximum of 190 to
20 215 and preferably 205 at a height of 2 to 7 and preferably 4 to 6 mm. The minim:~l and
m~im~l spreads A indicate that a very fluid artificial-resin mortar has spread out very far
at an already considerable thickness. Spread A can be regulated by regulating the
proportion of liquid component, especially water, in the mortar. Tank 52 is not just a tank
but serves to both prepare and store mortar 11. A specific amount of coloring can be added
25 and blended in while the mortar is being mixed to provide it with a desired color. A signal
representing spread A can also be forwarded to controls 42 to allow continuous processing.
The particular spread employed should ensure that mortar 11 has attained, before arriving
at a texturing device, enough hardness, although still moist, to retain any textures
established on its surface. The texturing device can be a robot with a comb 56 on the end
30 of an arm 55, producing a pattern, adjacent arcs for example, in what then becomes a
textured-mortar coat 12.
13
CA 02241069 1998-06-19
15736-032
As mortar 11 is applied and doctored, it will diffuse into the pores 22 in web 2.
The speed of web 2 and the hardening time and spread of mortar 11 determine to what
extent the mortar, especially any small particles it contains, can penetrate along with its
plastic constituent to the other side of the web.
The accordingly coated and saturated web 2 proceeds to a drying oven 62, where
it travels over an air-permeable grated device 57 in the form of a continuous air-permeable
linked-bar conveyor belt 58 that travels around deflection cylinders 59 and 60. The bars in
conveyor belt 58 are supported on strands of chain and the coated web 2 on the bars. Belt
58 is synchronized with belt 49, and the coated and saturated web travels through drying
oven 62 at the same speed v it is coated at.
Drying oven 62 accommodates radiators 63, sources of infrared radiation in
accordance with the present invention. The radiators, preferably hot-air blowers, accelerate
the curing of the plastic component of artificial-resin mortar 11. The curing is also
promoted by driers 61 under belt 58. Driers 61 can also be backed up by sources of
infrared radiation. The length of drying oven 62 depends on the particular drying time.
Coated web 2 leaves drying oven 62 in the form of a finished plaster-impregnatedwall covering 100 or 101.
Once artificial-resin mortar 11 has set, there will be a flexible coat 1 over the
upper side 21 of web 2, a layer 3 of impregnating mortar in pores 22, and another flexible
coat 1' over lower side 24. A dispersion 14 of plastic is distributed along with mineral
substances 15 as hereintofore described as mortar 11 is applied. As the mixture sets, its
regions 15 of mineral substances will be encapsulated in an adhesive envelope 17 and
connected by adhesive bridges 16. The individual mineral regions 15 will accordingly be
"linked" together and to the fibers 23 of non-woven web 2. This structure ensures the
properties of flexibility and easy handling typical of the plaster-impregnated wall covering
100 or 101 in accordance with the present invention.
The finished wall covering 100 or 101 is rolled up under tension by a winder 65.Winder 65 comprises a drum 67 with a long enough inside diameter to prevent the wall
covering from creasing or deforming as it is wound. Drum 67 is rotated by a mechanism
14
CA 02241069 1998-06-19
15736-032
68 in the form of a speed-controlled motor by way of an applopliate multiplication-and-
reduction tr:~n~mi~sion. Essential to the present invention is that wall covering 100 or 101
is wound into a roll 66 at the same speed v web 2 is advanced at. Regulated drive
mechanism 68 accordingly simultaneously ensures that speed v will remain constant as the
5 diameter of roll 66 increases. To ensure continuous operation, the wall covering is rolled
"on the fly", meaning that a full drum 67 is immediately replaced with an empty one. The
exchange is accomplished by guidance-and-diversion mech~ni~m~ that allow a freshcovering to be advanced at speed v and immediately rolled up by further mech~ni~m~ A
tensioning cylinder 64 keeps web 2 correctly positioned even while wall covering 100 or
101 is being rolled up. Tensioning cylinder 64 can be raised or lowered along with the
whole winding section or along with drum 67 alone.
The wall covering 100 or 101 on roll 66 has been sufficiently finished and "dried"
to prevent it from deforming when rolled up. Prior to further processing, however, it is of
advantage to leave the roll alone until the chemical reaction is complete.
How wall covering 100 or 101 is further handled will now be specified with
reference to Figure 6.
Figure 6 illustrates a room with a tiled floor 31 and a wall 30. Wall 30 is a slab of
prefabricated concrete of the type employed in structures in the recently ~imil~ted
German states. It is characterized by a large number of depressions in an otherwise smooth
, 20 surface. This characteristic considerably complicates covering. Furthermore, wallpaper
paste can accumulate in the depressions and spoil the appearance of the wall covering.
A web of plaster-impregnated wall covering 100 is accordingly applied directly to
this raw surface. It is particularly convenient here to use the tools and materials of
conventional house painting. The covering is trimmed as it is removed from the roll to the
25 height of the room. Side 24 or the coat 1' of mortar on it is provided with a dilute
dispersion adhesive. The web is then attached to the wall like any conventional wall
covering. Since side 24 or flexible coat 1' has an almost flat but rough surface, they
provide the adhesive with an interface that facilitates adhesion.
CA 02241069 1998-06-19
15736-032
The wall covering is brushed smooth and simultaneously pressed against wall 30
with a brush. Another web of plaster-impregnated wall covering 101 is then similarly
trimmed to size, its back provided with adhesive, and attached to the wall. Wall covering
100 and 101 are attached edge to edge like a raw-fiber wall covering, providing the wall
5 covering with a smooth appearance. The texture introduced into coat 1 can help conceal
the joints between the sections. Coat 1 can then be painted as desired, with its light
coloring contributing to the effect of the paint.
Since coat 1 is heat-resistant, the wall covering can also act as an extended heating
element if a network of electric-resistance wires is embedded in it, providing uniform heat
10 to the room when connected to a source of electricity. When such elements are combined
with conventional in-the-floor heating, the room can be provided with a moderatetemperature gradient. Spaces that can benefit from such a treatment include operating
rooms, laboratories, and facilities for raising such small animal as chicks and piglets. Such
rooms, however, require not only very moderate gradients but also washable surfaces. The
15 easy-to-handle surface of flexible coat 1 is simple to tile or cover with some other type of
washable material.
The embedded grid of electric-resistance wire will not only heat the space
uniformly but will also act as a Faraday cage, keeping out electromagnetic waves.
Covering the walls of all types of space from laboratories to very high-tension test shops
20 will accordingly ensure uncont~min~ted measurements. It is essential to the present
invention that the mesh of any grids embedded in the flexible coat be constant, 10 to 20
mm2 for example. This feature will elimin~te the need for cladding with expensive
corrugated metal sheet or for metal ribbing under the plaster. The elec,tromagnet screening
will be accompanied by high heat insulation, decreasing the expense of heating the space.
Plaster-impregnated wall coverings with embedded electric-resistance wires can
also be employed in saunas and similar spaces. The wires will ensure uniform heat. The
web 2 in the wall covering will not only insulate but will also, like the mortar itself, resist
the prevailing high temperatures with no alteration in materials properties.
16
