Note: Descriptions are shown in the official language in which they were submitted.
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CEMENT IN A ROLL FOR APPLICATION TO
T~E SURFACE OF A BUILDING
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BACKGROUND OF THE INVENTION
This invention relates to a composite covering material
for finishing the surface of a building and to the use thereof
to provide permanently adherent decorative cement-based surfaces
on buildings.
The application of a finish to the surface of a building
is often necessary because buildings are generally constructed
from the most economical available materials selected for their
load bearing and structural characteristics, without regard to
their appearance. Thus, a finish is necessary to enhance the
appearance of the building or to give protection against the
elements, and the like.
Although cement has commonly been used as a finishing
material for surfaces of buildings, the use of cement entails
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several practical difficulties. Normally, cement is prepared
at the job site and applied by troweling or spraying to the
surface being covered. It will be apparent that the character-
istics of surfaces obtained by troweling are almost exclusively ~ -
dependent on the skill of the workman applying the cement, and
that the decorative qualities of surfaces thus prepared are
frequently of uneven quality. When cement is applied by spraying,
the operation is objectionable owing to the need for masking sur-
faces which are not to be covered and to the clean-up required
as well as to the fact that hand finishing is often necessary.
Other objections to the practice of preparing and apply-
ing cement at the job site include the lack of reproducibility
am~ng several batches of purportedly identical cement mixes as
well as the necessity of accurately predetermining the amount
of ~emt~t which can be applied from a given batch, so that unused
cement does not have to be discarded. ~-
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Another problem inherent in the application of cement
compositions to structural surfaces is the poor adhesion
qualities of cement to many of these surfaces. Thus, when cement
as is commonly the case, is the adhesive between a structural
member and the cement or other finishing material, the permanency
of the finish depends on the "keying" or "locking" of cement
paste in pores, cracks and crevices of the surface. Because the
locking action of cement is relatively weak, a cement finish is -
subject to delamination and may separate and fall away from the
building surface under normal stresses of expansion, contraction,
vibration and settling of buildings.
In the refurbishing of older buildings, it is usually
very difficult to obtain a good bond between old cement surfaces
and a new covering or finishing layer.
A further disadvantage of using cement as the finishing
layer by the spraying or troweling techniques, is that several
coats or layers may be required. This is not only time consuming
and expensive, but adds unnecessary weight to the building so
that stronger and more costly load bearing members must be used.
It is known in the art of finishing a surface of a
building to apply thereto a fully processed veneer layer consist-
ing of split natural crystalline stone bonded by a thermoplastic
synthetic resin in a bearing layer, which is a textile or metallic
net, as taught by Gurgui et al, in United States Patent No.
3,705,830. However, the deficiency of this method is that the
veneer must be bonded to the surface using a mortar of hydraulic
binder, such as cement or cement with lime, which has the objec-
tionable properties pointed out above.
The difficulty of bonding hard ceramics, such as alumina- -
based ceramics, to rubber or other organic resins is pointed out
in ~eninga, United States Patent No. 3,666,613, and the problem
is solved by metallizing the surface of the ceramic. It is
clearly apparent that the expense inherent in this process
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precludes its use except under very exceptional circumstances.
Wagner, in United States Patent No. 3,030,258, teaches
the preparation of an improved mortar composition containing an
organic resin, but it will be understood that Wagner contemplates
mixing the mortar and applying it at the point of use.
Thus, in the field of finishing the surfaces of buildings,
there is a continuing need for an economical, convenient, clean
method of applying cementitious compositions to interior and
exterior surfaces so that the cementitious coverings will bond
permanently to any kind of surface, be available in a wide variety
of textures and finishes, and be of uniform quality.
In accordance with this invention, it has been found that
unset cement fabricated in the form of a roll or sheet can be
applied economically, conveniently and neatly to surfaces of
buildings and bonded permanently to any kind of surface. The
cement rolls of this invention further provide a wide variety
of aesthetically pleasing surfaces not otherwise readily avail-
able and provide ceme~t coverings of a reliable quality regardless
of the ultimate point of application.
SUMMARY OF THE INVENTION ;
More particularly in one broad aspect the invention
comprehends a flexible covering material suitable for finishing
a surface of a building which covering material includes a matrix
layer covered with and at least partially embedded in water-
curable composition. The water curable includes a combination
of a polymer binder and a cement mix wherein the cement mix is
from 85~ to 95~ of the water-curable composition and the covering
material has sufficient flexiblity to be rolled into a roll -
or transporting.
The invention further comprehends a flexible wall cover-
ing material suitable for finishing a surface of a building which
comprises a flexible matrix layer covered with and at least
partially embedded in water-curable composition. The composition
; ~ includes a combin~tion of a polymer binder and a Portland cement
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mix wherein the cement mix is from 85% to 95% by weight of the
water-curable composition. The Portland cement mix includes from
zero to about 70% by weight of a filler. The composition produces
a planar substantially uniform layer by being deposited on the
matrix layer with a solvent therein which is substantially
removed. The covering material having sufficient flexibility to
be rolled into a roll for transporting and subsequently unrolled
for being applied to a surface without the composition separating
from the matrix layer or cracking.
The invention in another aspect comprehends a method
for preparing a flexible cementitious covering material for the
surface of a building which comprises the steps of applying to
a matrix layer a covering composition consisting of from about
85 to about 95 parts by weight of a cement mix and from about
15 parts to about 5 parts by weight of a polymeric binder and --
from about 10 to about 30 parts by weight of an organic solvent,
and removing the organic solvent by evaporation.
A still further aspect of the invention relates to a
method for permanently covering a surface of a building which
comprises adhering thereto a flexible cementitious covering
material by bonding a matrix layer of the covering material to
the surface of the building. The covering material consists of
the matrix layer covered with and at least partially embedded in
a water-curable composition which includes the combination of
a polymer binder and a cement mix wherein the cement mix is from
85~ to 95% of the water-curable composition. The covering
material having sufficient flexibility to be rolled into a roll
for transporting.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of this invention
will become apparent from the description and drawings below,
in which
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Figures l and 2 show magnified views of cross sections
of the cement rolls of this invention,
Figure 3 shows an installation for making the cement
rolls of this invention, and
Figure 4 shows application of the cement in a roll to
a structural surface. ~ :
DESCRIPTION OF THE PREFERRED EMBODIMENT -
THE CEMENT MIX -
"Cement mix", as used herein, refers to a combination
of Portland cement, fillers and admixtures used in the cement
rolls of this invention. Fillers usable in the cement mix of -
this invention include aggregates such as sand, limestone, glass
chips, marble dust, talc, clay, mica, carbon black, bentonite,
perlite and gravel. Suitable admixtures include those which will
improve product hardness, impart color, reduce sagging, reduce
shrinkage, or decrease foaming during processing. Other admix-
tures appropriate for the cement mixes of this invention include
reinforcing filamentary fibers, such as whiskers of glass,
asbestos or metal for exceptionally high structural strength,
resistance to weathering and corrosion, and decreased thermal
conductivity. When glass fibers are used in the cement mixes of
this invention, the fibers should be treated to resist the alkali -
present in the cement.
The amount of cement mix including fillers in *he paste
or slurry will generally consist of from 70% to 82~ by weight
of the total slurry. The slurry includes the cement mix, a
polymeric binder, a plasticizer, and a solvent and dispensing
agent. After the organic solvent is removed by drying, the
cement mix remaining generally consist of from 85% to 95% and
the polymeric binder consists of 5% to 15% by weight excluding,
of course, the weight of the matrix layer.
For economy, the cement rolls of this invention, the
higher amounts of cement mix, especially amounts above about 90%
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by weight of the combination, are preferred.
The fillers used in the cement mixes for the cement rolls
and sheets of this invention will generally be of small particle
size, of the range below about 0.5 millimeters, and preferably
below about 0.2 millimeters. The amount of filler, or combination
of fillers, usable in the cement mixes of this invention can be
as high as about 70% by weight of the cement mixture, that is,
up to about as much as 65% by weight of the combin~d cement mix-
binder combination. If higher amounts of fillers are used, the
resulting water-cured cement product tends to crumble owing to
the low level of true cement bonds in the final composite.
Portland cement is a powdered material which, when
mixed with water, forms a paste which hardens slowly to bond
intermixed crushed rock, gravel, sand or other fillers into ;
concrete of rock-like hardness. Portland cement is made by
sintering a mixture of raw materials, one of which is primarily
calcium carbonate, i.e., limestone, and the other of which is
primarily aluminum silicates, e.g., clay or shale. The sinter-
ing process causes the occurrence of chemical changes which
produce nodules, known as clinkers, consisting mainly of calcium ;`
silicates and aluminates. Portland cement of commerce is the
foregoing clinker pulverized with a small amount of calcium
sulfate. Portland cement is differentiated from other types of
commercial cements by the different phases of which it is formed
and by fulfillment of certain standards established by regulatory
and testing authorities. See, generally, R. H. Bogue, "Cement"
in Kirk-Othmer, "Encyclopedia of Chemical Technology" II, Volume
4, Interscience Publishers, New York (1964) after 684.
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Although Specification C 150-63 of the American Society
for Testing and Materials (A.S.T.M.) differentiates Portland
cements into five types, Type I, which is designated for use in
general concrete construction when the special properties of
Types II, III, IV and V are not required, will generally be the
preferred type of Portland cement for the practice of this
invention. It will be appreciated that special use Portland
cements, such as Types II, III, IV and V can also be used in
the practice of this invention.
THE POLYMERIC BINDER
"Polymeric binder", as used in the specification and
claims, means a thermoplastic polymer, whether in the form of
a solution, dispersion, latex, or solid, which will adhere the
cement mixes of the present invention to the flexible matrix
layer and which will maintain the uncured cement mixes in a
flexible condition during extended periods of storage prior to
use at a building site.
Typical of the thermoplastic polymers which can be
used as binders in the practice of this invention are polyvinyl-
acetals, Polyacrylates, polyvinyl chloride, alkyd resins, andcellulosic resins, such as cellulose acetate and isobutyrate.
Preferred thermoplastic resins for the purposes of this
invention are polyvinylacetals, such as polyvinylbutyral, and
acrylate resins. Typical of the polyvinylacetal resins preferred ~ -
for the practice of this invention is polyvinylbutyral, such as
a 25~ solution known commerically as Butyral Solution L-7124,
obtained from Raffi and Swanson, Inc.
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Typical of the acrylic resins suitable for the practice
of this invention is polymethyl methacrylate such as ACRYLOID~
B-50 or ACRYLOID~ B-48N, manufactured by the Rohm and Haas Co.
When an acrylic polymer is used in the binding compcsition of
this invention, it is frequently desirable to use a plasticizer
in order to improve the flexibility of the resulting composite
material. Typical of the plasticizers which can be used are
ester plasticizers, such as PARAPLEX ~ G-30, commercially
available from the Rohm and Haas Co., and SA~TICIZERS ~ 160,
261 and 262, supplied by the Monsanto Chemical Corp.
Acrylic polymers used in the water-curable compositions
of this invention may also be combined with other resins, such
as conventional solvent grade acrylic resins, alkyd resins,
vinyl resins and cellulosic resins. A combination of an acrylic
resin with a second resin, such as polyvinyl chloride, and a
plasticizer may also be used.
The amount of polymeric binder used in the water-curable
compositions of this invention will be from about 5% to about
15% by weight after curing of the cement mix-polymeric binder
total, including any plasticizer. Use of binder in amounts
below 5% by weight gives a cement roll product in which the
cement mix does not adhere well either to itself or to the
matrix layer. Use of polymeric binder in amounts above abo~t
15~ by weight gives no substantial improvement in properties
over a lower level of polymeric binder, which is the more
expensive component of the cement mix-polymeric binder
~: combination.
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THE ~ATRIX LAYER
The matrix layer or supporting material for the cement
rolls and sheets of this invention may be any natural or syn-
thetic woven or non-woven fabric or mesh. The basic material
may be paper, fiber glass, flexible metal mesh, polyester, poly-
olefins, polystyrene and the like, as well as natural fibers or ~ ~
asbestos. ~-
The material chosen as the matrix layer should be
characterized by ease of handling and cutting, good workability, ;~
high strength, low flammability, and resistance to deleterious
atmospheric conditions. The material can be treated to impart
resistance to fungi and rodents. Normally, the cost and avail-
ability of a material will be important considerations.
Typical of the matrix layers suitable for the cement
rolls of this invention is non-woven polypropylene cloth as is
often used as backing for indoor-outdoor carpeting. Woven
fiberglass scrim material is equally suitable. Fiber reinforced
paper or woven kraft paper are quite useful as matrix layers, ;-
as is open weave polyester scrim cloth.
A porous flexible support material i9 preferred for the
matrix layer of these cement rolls because it provides a good
surface for adhesion to the cement mix-polymeric binder being
applied thereto and partially embedded therethrough. Thus, an
open weave mesh material allows the cement mix-polymeric binder
combination to penetrate and at least partially encapsulate the
support material so that the cement is integrated
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into the product. Of the acceptable maxtrix materials, woven -
and loosely knit materials, such as woven kraft paper, woven
fiberglass, and open weave polyester scrim cloth are preferred.
In Figure 1 is shown a cross-sectional view of a typical
embodiment of the cement rolls of this invention. The rolls
consist of a flexible matrix layer, e.g., woven kraft paper, ~ -
(1) which is bonded to and which is partially embedded (5) in
the water-curable combination (2) consisting of cement mix and
polymeric binder. The surface of the water-curable combination
may be decorated as at (3) or level as at (4).
In another embodiment of this invention, shown in
Figure 2, the matrix layer (11) is a loosely knit fabric, coated -~
with a water-curable composition (12) containing glass fibers
(13) for reinforcement. Macroscopic aggregate particles (14)
are embedded in the water-curable composition distal to the
matrix layer.
Preparation of the- Cement Rolls
The cement rolls of this invention are prepared by
depositing on and partially through the matrix layer a covering
20 composition consisting of cement mix, a polymeric binder, and an -
inert organic solvent and removing the inert organic solvent.
.
By "covering composition" is meant a paste or thick
slurry consisting of from about 85 parts to about 95 parts by
weight of cement mix, from about 15 parts to about 5 parts by
weight of a polymeric binder, and from about 10 parts to about
30 parts by weight of inert organic solvent.
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Inert organic solvents which are useful for this purpose
include ethanol, toluene, isopropyl alcohol, Methyl acetate,
benzene, xylene, acetone, methyl isobutyl ketone, and the like.
The amount of solvent used will generally and preferably
be such as to give the covering composition being applied to the
matrix layer a viscosity from about 40,000 to about 60,000 centi-
poises at room temperature. It will be understood that covering
compositions of higher or lower viscosities can be handled if
specialized equipment is available.
After the covering composition has been applied to the
surface of the matrix layer and partially embedded therein,
solvent is removed, usually by heating. Generally, the heating
will be below about 200 degrees F. because this is often the
softening point of the thermoplastic binders used in the covering
compositions.
A typical installation for making the cement rolls of
this invention is shown in Figure 3, wherein matrix layer (21) is
passed over rollers (22) while covering composition ~23) is
applied from a hopper or other applicator device. The surface
of the covering composition is leveled and made smooth by a
doctor blade or any other suitable device (24) before the com-
posite material is passed into a drier (25) which may be equipped
with a condenser (26) for the recovery of organic solvent. The
product is collected in the form of a roll (27).
In another typical installation, the doctor blade may
be supplemented by an embossing tool to provide a product with
any desired texture or design. ~
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When a product is to be prepared with macroscopic
aggregate particles embedded in the surface of the water-curable
composition distal to the matrix layer, an installation similar
to that in Figure 3 can be used, provided that an additional feed
device for macroscopic particles, usually of the order of 0.5-5
millimeters grain size, is provided between the feed device for
the covering composition and the drier.
The dried product may be stored in rolls, as illustrated
in Figure 3, or may be cut into sheets, which can be stacked.
Either product can be conveniently shipped to the site of use.
Application of the Cement Roll
The method of applying the cement in a roll to the sur-
face of a building is illustrated in Figure 4. Adhesive mater-
ial (32~ is applied either to the surface being covered (31)
which is pressed against the building surface until good adhesion
is obtained or to the back surface of the roll. Curing of the
water-curable composition (34) of the cement roll will be accom-
plished by exposure to moisture in the air. However, it is
frequently desirable to spray the cement roll, after application
to the surface of a building, with a fine mist of water to pro-
vide water for the cure.
There is a wide variety of various latex adhesives that
are suitable for use in the present invention. However, a
polyvinyl acetate water emulsion has perfor~ed admirably because
of its ease of formulation, price and ultimate physical proper-
ties. Other later adhesives which are also suitable include:
vinyl-acetate-ethylene copolymers, polyvinyl chloride, polymers
or copolymers of acrylic acid, acrylonitrile-butadiene copolymers,
I chlorinated rubber, neoprene, polyisobutylene, SB-R rubber,
¦ 30 Butyl rubber.
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It will be apparent that sheets of material prepared
according to this invention are applied in the same fashicn.
The adhesive layer used to bond the cement roll of this
invention to the building surface being coated will be selected
according to the nature of the surface and the nature of the
matrix layer used.
The following examples of covering compositions of this
invention are presented only as typical of the compositions of
this invention and not as limitative thereof.
Example 1
Pounds Component
100 Cement mix--50% Portland cement Type I
50% sand
18 Polyvinylbutyral solution
(25% solids) (binder)
16 Isopropyl alcohol (99%) (solvent)
Cement rolls obtained from this composition produces a
cured product which is relatively resistant to water and is
stable to weather and atmospheric conditions.
Example 2
Pounds Component
100 Cement mix--40% Portland cement Type I
60% carbon black
Acrylic polymer--ACRYLOID ~ ~-50 (binder)
(44-46~ solids)
18 Toluene (solvent)
Cement roll prepared using this composition was somewhat
less flexible than the roll produced from the composition of
Example 1 and showed a tendency to crack.
Example 3
Pounds Component
100 Cement mix--40% Portland cement Type I
60% carbon black
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6 Acrylic polymer--ACRYLOID ~ B-50 (binder)
6 Plasticizer--PARAPLEX ~ G-30
17 Toluene (solvent)
Cement roll prepared using this composition produced a
cured product with excellent weathering properties. The roll
had the same flexibility as those prepared using the composition
of Example 1 and showed no tendency to crack before use. ,~ .
Example 4
Pounds Component
100 Cement mix--35% Portland cement Type I
65% crushed limestone
4 Acrylic resin--ACRYLOID ~ B-50 (binder)
4 Polyvinyl chloride--VYRAM ~ 28100 (binder)
4 Plasticizer--PARAPLEX ~ G-30
17 Toluene (solvent)
Example 5
Pounds Component
100 Cement mix--40% Portland cement Type I
60% silica -
8.5 Acrylic polymer--ACRYLOID ~ C-lOLV (binder)
4 Plasticizer--SANTICIZER ~ 261
Isopropyl alcohol (solvent) ~ ~ -
Example 6
Pounds Component
100 Cement mix--50% cement
45% sand
5% yellow pigment -
8 Acrylic polymer--ACRYLOID ~ B-48N (binder)
2 Plasticizer-SANTICIZER ~ 262
Methyl acetate (solvent)
Cement rolls can be obtained from compositions of
Examples 4 - 6 which exhibit satisfactory flexibility, stability
on storage, and ease of application to building surfaces.
While a preferred embodiment of the invention has been
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described using specific terms, such description is for
illustrative purposes only, and it is to be understood that
changes and variations may be made without departing from the
spirit or scope of the following claims.
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