Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a hardenable coating com-
position which is suitable for application onto a surface by
trowelling. The invention is a modification of the invention
described and claimed in Canadian patent application No. 165.321
which claims a process for preparing a hardenable coating
composition suitable for application onto a surface by
trowelling, comprising mixing one part by weight of a
liquid water-insoluble resinous binder with from 5 to lO
parts by weight of small inert particles, and adding to
the mixture with stirring from 0.5 to 2 parts by weight of
a dilute aqueous solution of a water-soluble polysaccharide
compound. Compositions as claimed in the aforesaid patent
specification are particularly useful to cover a surface,
such as floors or walls, with a layer which when cured is
impermeable for contaminants and which thereby protects the
underlying surface; specific advantages are that such com-
positions do not stick to tools such as mixer or trowel,
and that they are smoother and more kneadable than corre-
sponding compositions which do not contain the dilute aqueous
solution of polysaccharide compound.
It has now been found that such compositions which
contain considerably more than lO parts by weight of small
inert particles per part by weight of water-insoluble binder
can also be applied by trowel, and can find particular use
in cases where permeability for water and other liquids can
670
be allowed, such as for egalization of very rough substrates, or as filling
material, e.g., for damaged concrete before a top layer is applied, in
particular when the surface will be covered with an impermeable top layer.
For applications as described above, sand-cement mortars are
often used; these, however, have the disadvantage of dusting during pouring
the cement and making the mortar; further they have to be kept wet for a
rather long time (more than a week) for development of optimum strength;
also the hardened sand~cement mortars are not acid-resistant. ~ -
The novel compositions, on the other hand, do not or scarcely
dust during preparation, and the layers applied need only about 24 hours
to harden and dry; further the layers are acid-resistant.
Thus this invention seeks to provide a process for preparing - -
a hardenable coating composition suitable for application onto a surface
by trowelling, comprising mixing one part by weight of a liquid water-
insoluble resinous binder with between 10 and 100 parts by weight of small
inert inorganic partîcles having a particle size of at least 74 microns,
and adding with stirring 0.5 to 2 parts by weight of a dilute aqueous
solution of a water-soluble polysaccharide compound, wherein the liquid
resinous binder comprises an epoxy resin and a water-insoluble amino com-
pound having per molecule on average at least two amino hydrogen atoms,
or an unsaturated polyester.
The liquid resinous binder comprises as the hardenable compo-
nent preferably an epoxy resin, and as a hardener for the epoxy resin a
water-insoluble amino compound having per
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molecule on average at least two amino-hydrogen atoms.
Epoxy resins containing from 80 to 100% by weight of a
polyglycidyl ether of 2,2-bis(4-hydroxyphenyl)propane,
having an average molecular weight between 340 and 500,
are preferred; these polyglycidyl ethers are usually viscous
liquids at ambient temperature. The remainder, if any, of
the epoxy resin may be a liquid epoxide of low viscosity,
such as butyl glycidyl ether, phenyl glycidyl ether, cresyl
glycidyl ether, glycidyl esters of saturated aliphatic
monocarboxylic acids having from 9 to 11 carbon atoms per
moleculej wherein the carbon atoms of the carboxyl group
are bound to a tertiary or quaternary carbon atom, diglycidyl
ether of ethylene glycol, or diglycidyl ester of 2,2,4-tri-
methyl adipic acid; these epoxides of low viscosity act as
reactive diluents for the viscous polyglycidyl ether, and
reduce the viscosity to the desired level.
The amino compound used in the present process in com-
bination with the epoxy resin should be water-insoluble,
that is to say that it should not dissolve readily or to an
appreciable extent in water in the weight ratios in which
the amino comppund and the aqueous solution are used. Water-
soluble amino compounds dissolve in the aqueous phase in
the present process, which retards the cure or even may
prevent complete cure.
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Suitable water-insoluble amino compounds as defined
above are in general reaction products of aliphatic, cyclo-
aliphatic or aromatic primary polyamines with epoxides, or
with phenols and aldehydes. Examples of primary polyamines
suitable for preparing such water-insoluble amino compounds
are: ethylene diamine, diethylene triamine, di(4-amino-
cyclohexyl)methane, dit3-methyl-4-amino-cyclohexyl)methane,
isophorondiamine(3,5,5-trimethyi-3-aminomethylcyclohexyl-
amine), xylylene diamine(di-(aminomethyl)benzene), diamino
diphenyl methane, and diamino diphenyl sulphone. It is
noted in this connection that even for aliphatic poly- -
amines which are readily soluble in water, such as di-
ethylene triamines, the modification by reaction with an
epoxide, or with phenols and aldehydes can reduce the water
solubility to an acceptable level.
Examples of water-insoluble amino compounds are re-
action products of primary polyamines with monoglycidyl
compounds in a 1:1 molar ratio. Suitable monoglycidyl com- -
pounds for forming such reaction products are, for example,
phenyl glycidyl ether, cresyl glycidyl ether, and glycidyl
esters of saturated aliphatic monocarboxylic acids having
from 9 to 11 carbon atoms per molecule wherein the carbon
atom of the carboxyl group is bound to a tertiary or quaternary
carbon atom.
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Very suitable water-insoluble amino compounds are -
reaction products of primary polyamines with polyglycidyl
ethers of 2,2-bis(4-hydroxyphenyl)propane having an average
molecular weight between 340 and 500 in molar ratios of
polyamine to polyglycidyl ether of between 1:0.1 and 1:0.2,
and optionally with glycidyl esters of saturated aliphatic
monocarboxylic acids having from 9 to 11 carbon atoms per
molecule, wherein the carbon atom of the carboxyl group
i~ bound to a tertiary or quaternary carbon atom, in molar
ratios of polyamine to glycidyl ester between 1:0.4 and
1:0.6.
Other very suitable water-insoluble amino compounds are
condensates having at least two amino hydrogen atoms per
molecule of primary diamines with phenols and aldehydes,
such as formaldehyde, for example, the condensates described
in the British patent specifications 789,475 and 868,892
and in the German patent application 1,953,643. Condensates
of this type contain free phenolic groups which accelerate
the cure of the epoxy resin.
The water-insoluble amino compound may be diluted with
small amounts of solvents to improve the fluidity and to
facilitate mixing with the epoxy resin.
The water-insoluble amino compound and the epoxy resin
should be kept stored separately, and these two components
~hould be mixed only shortly before use, as the components
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begin to react slowly immediately after being mixed, and
the pot life (the time that the mixture is sufficiently
fluid to be worked) is rather short.
The ratio of epoxy resin and amino compound is as
usual in the art, that is in general from o.8 to 1.2
amino hydrogen equivalent per epoxy equivalent.
The liquid resinous binder which contains epoxy resin
may contain additional components, for example, low-
volatile liquid extenders, such as pine oil, coal tar,
refined coal tar or aromatic extracts of petroleum
distillates. Other useful additives are curing accelerators,
such as phenolic compounds, for example, phenols such as
phenol, cresols, xylenols or preferably salicylic acid.
Other types of liquid resinous binders are, for example, ;
unsaturated polyesters, optionally modified by addition
of styrene, and hardenable with free-radical catalysts or
metal salts.
The aggregate or filler used in the present invention
is com?osed of small inert inorganic particles having a
particle size of at least 74 microns, preferably between
74 microns and 2.0 mm, more preferably between 0.1 and
2.0 mm. A suitable aggregate is sand, but other filler
materials may be added. A graded sand may also be used,
such as a graded sand having a particle size between 0.1
and 2.0 mm. Part of the aggregate may be of larger size than
2 mm.
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The amount of aggregate or filler is in general from 10 to 100,
preferably from 20 to 80, parts by weight per part by weight of liquid
resinous binder. When the aggregate is sand with a particle size distribution
in the range of from 0.1 to 2 mm, and preferably from 0.2 to 2 mm, the
present compositions and the resulting hardened layers made therefrom may
have the following characteristics:
(1) Filler/binder weight ratio between 10:1 and 20:1; compo-
sition easily trowellable, cured layer has usually low permeability for
water and high strength. Use in top layers for floors and walls (when high
strength is required, and some permeability for water can be tolerated) and
stopping compounds, e.g., for damaged concrete, without application of a
surfacing compound.
(2) Filler/binder weight ratio 20:1 to 60:1; composition
trowellable, cured layer is permeable for water and organic liquids and has
a strength higher than or comparable with the strength of fully hardened
sand/cement mortars. Use for egalization of very rough surfaces on places
where impermeability is not required or before application of an impermeable
top layer.
(3) Filler/binder weight ratio between 60:1 and 100:1; compo-
sition still trowellable, cured layer permeable for water and organic
liquids, with strength comparable with or
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lower than the strength of fully hardened sand/cement
mortars. Use for egalization of rough surfaces where
strength does not matter, such as on certain types of
walls, and on floors where resistance to local forces
is completely taken up by a high strength top layer.
For the purpose of the present invention a dilute
aqueous solution of a water-soluble polysaccharide compound
is added to the mixture of liquid binder and aggregate.
In this context dilute is preferably an amount of from -
0.25 to 1 per cent by weight of polysaccharide compound
in the water. Polysaccharide compounds are those poly-
saccharides and derivatives thereof, such as ethers, which
do not resemble sugars.
The water-soluble polysaccharide compound may be a
true polysaccharide such as starch or dextrine. Starch may
be dissolved in hot water, whereafter the solution is
cooled for use in the present in~ention. Dextrine - a
hydrolyzed starch - can usually be dissolved in cold water.
The polysaccharide compound may also be a polysaccharide
ether, such as a cellulose ether, that means a cellulose
in which free hydroxyl groups of the cellulose have been
converted into ether groups. Examples are methyl cellulose,
hydroxyethyl cellulose, and salts of carboxymethyl
cellulose (CMC).
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In the present process the sequence of adding the
various components bears some weight. The liquid resinous
binder is usually added to the aggregate in a type of
dough kneader or concrete mill. When the mass is homogeneous
after some minutes, the aqueous solution of polysaccharide
compound is added, and the mixing is continued for a short
time, usually below 1 minute when the total amount of the
mixture is small. The mass can then be removed from the
mixer, and stored, if desired, for a short time.
The mixture of aggregate and liquid resinous binder has
a consistency which varies with increasing aggregate/binder
ratio from crumbly to merely wetted sand. On addition of
the dilute aqueou~ solution in the rather small weight ratios
specified above the consistency changes into that of a
trowel~ble mass.
The surface to be covered with the mass so prepared is
preferably first covered with a thin "tack" coat of liquid
resinous binder without aggregate, to ensure good adhesion.
The filled, thoroughly blended mass can then be spread
evenly over the desired area by means of a trowel, roller,
screed, or vibratory screeder, and if desired, finished with
a trowel. Trowel, roller and screed are preferably from poly-
ethylene or polypropylene, to better prevent any sticking of
the material to it. ~ -
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Mixer and trowel or other apparatus can be easily
cleaned with water, or by wiping with a wet cloth.
The surface to be covered may be concrete, stone, steel,
asbestos cement or wood; if the surface is dirty it has first
to be cleaned as known in the art; for concrete the last
stage of cleaning is usually an etching with dilute hydro~
chloric acid, followed by cleaning with water, and drying;
steel can be cleaned by treatment with a degreasing solvent
followed by sand blasting, brushing or grinding; wood is
preferably taken down to clean wood with a sander.
After application of the coating the layer is allowed
to cure during which time the water can also evaporate.
The cure is usually performed at ambient temperature;
accelerated cure (and evaporation of water) may be attained
by moderate heating, for example with an infrared ~ating
device.
Surfaces of cured masses according to the invention
can, if dèsired, be covered with top layers or surface
coatings or surfacing sheet material, loose or glued onto
the layer prepared according to the invention.
For improving the adhesion when a resin-containing
mortar is used for the top layer, it is preferred to first
impregnate the surface with a "tack" coat of liquid resinous
binder without any aggregate. The surfacing mortar may be
of the type as described in the aforesaid patent specification,
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with or without aqueous polysaccharide solution. The top
layer may also be a self-levelling compound, that is a
resinous composition containing such an amount of filler
that the composition upon pouring and perhaps slight egalization
levels out itself into a smooth level layer before the hardening
sets in.
The cured layer made according to the invention may also
be covered with a ~int coating, that is a thin layer of a
flowable composition which hardens by evaporation of liquid,
and/or by the action of cross-linking agents. A further means
'~ to cover a layer as described is by surfacing with a sheet
-- material, such as tiles or sheets of materials, such as
linoleum, colyvinyl or a carpet material.
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~he invention is illustrated by an example. The epoxy
; 15 resin was a liquid polyglycidyl polyether of 2,2-bis(4-
hydroxyphenyl)propane diluted with 9% by weight of cresyl
glycidyl ether; the viscosity was 50-60 poise at 25C.
Curing agent A was a liquid adduct of xylylene diamine
with a liquid polyglycidyl ether of 2,2-bis(4-hydroxy-
phenyl)propane and glycidyl esters of saturated aliphaticmonocarboxylic acids having from 9 to 11 carbon atoms per
molecule, wherein the carbon atom of the carboxyl group
is bound to a tertiary or quaternary carbon atom, in molar
,, .- ,
ratios of 1:0.16:0.53, diluted with 18 pbw benzyl alcohol; -
it was applied in a weight ratio epoxy resin/Curing agent A
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of 1.0:0.7. ;~
Curing agent C was a liquid condensate of xylylene
diamine with phenol and formaldehyde, diluted with benzyl
alcohol to give a Brookfield viscosity of 3.35 poise at
22C; it was applied in a weight ratio epoxy resin/Curing
agent C of 1.0:0.5.
EXAMPLE
The formulations were prepared by mixing the dry filler
component (sand) with the binder mixture (epoxy resin and
curing agent, mixed in a separate vessel with stirring
during 2 minutes). Then a 0.5% by weight solution in water
of a commercial hydroxyethyl cellulose was added with
stirring (1:1 weight ratio binder mixture/aqueous solution).
A tack coat was applied onto an existing concrete floor
(which was first cleaned with methyl ethyl ketone). Then
the formulations according to the invention were applied
by trowel. After complete hardening (28 days at 23C) the
strength was determined.
The resinous binders consisted of epoxy resin and
Curing agents A and C in weight ratios as indicated above.
The filler was a graded sand, 65 wt.-% having particle size
1-2 mm and 35 wt.-% having particle size 0.2-0.5 mm.
Flexural and compressive strength were determined according
to DIN 1164.
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The filler/binder weight ratios were varied, and
figures for strength were assorted according to the Table
below.
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Filler/ Curing agent ~ Curing agent C
weight Flexural Com-~ FleXural Com- Schmidtsen
ratio strength pressive strengt2h pressiv~ Hammer
(kg/cm2) strength(kg/cm ) strengt~ strength
;(kg/cm2) (kg/cm2) (kg/cm2,
DIN 4240)
. 25:1 127 180.5 67 149 260
35:1 108 141.5 58 124.5 225
50:1 102 124 49 94 170
75:1 26 29 150
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The surface could be walked upon after only 4 hours
without damage, and could be sealed or provided with a top
layer after 24 hours.
i~ :
For comparison, a fully cured layer of a sand/cement/
, water mortar (4:1:0.5 weight ratio) had a flexural and
compressive strength of 30 and 110 kg/cm2, respectively,
after having been kept wet during 28 days.
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