Note: Descriptions are shown in the official language in which they were submitted.
CA 02411329 2002-11-07
1
A masonry staining composition, a method of coating a masonry structure and a
method of producing a masonry structure, a method of producing a masonry unit
Field of the invention
The present invention relates to a method of coating a brick or masonry
structure and a
method of producing a brick or masonry structure whereby a brick or masonry
staining
composition is applied to a brick and masonry structures after construction so
as to make the
brick and or masonry stricture appear to have the Look, feel or texture of the
masonry product as
it was prior to being tinted.
to Background of the invention
Brick tinting has been a specialised proccas for a specialised market. Brick
tinting is used
to repair brick wall colours so that when a building extension is constructed
the new bricks can
be made to match the old bricks. Other applications include the repair of
builder's errors where
they organise the delivery of incorrectly coloured bricks and the error is
only noticed after
t 5 construction has begun.
The brick tinting process is a highly specialised, labour intensive process
and is thus
expensive, but is sometimes the only remedy available. This is particularly
the case when old
structures require extensions, but the clays from which the original bricks
were made are no
longer available. This matching of colour can be crucial to adding extensions
to heritage and
2o national trust structures.
The brick tinting process is applied by coating each brick individually as the
base colour
of the brick tlltlSt be takcrl lllto account, and the colour of the tint
adjusted so as to ensure that the
final result will be the desired colour.
Rendering, bagging and painting of bricks has been known for a considerable
time but in
25 all cases the final result produces a structure; or appearance whereby the
brick appears to be
coated and the natural texture of the brick or masonry is modified. In some
markets this an
undesirable effect.
The applicant does not concede that the prior art discussed in the
specification forms part
of the common general knowledge in the art at the priority date of this
application.
CA 02411329 2002-11-07
Summary of the invention
2
Throughout the specification and claims the terns "reactivity" is used as
measure of the
speed and or extent of a masonry surface to wet out by absorbing into the
surface. This reactivity
characteristic is a function of the surface's porosity, the depth of pores,
the structure and
interconnected volume of those pores and is an indication of capillary action
or suction available
to absorb a tinting composition. There are proposed two methods of testing
reactivity of a
masonry surface, the first test being the Wet Area test and the second being
the Total Absorption
test, both of which are hereinafter defined in the description below.
The present invention provides a method of producing a masonry structure, said
method
including the steps of:
selecting or producing a masonry product having one or more face surfaces with
a reactivity
equivalent to a wet out area of approx 1 to 5 square inches (G to 34 square
centimetres) by the
Wet Area Method as herein defined or within approx 10 to 60 seconds by the
Total Absorption
Method as herein defined;
is constructing a structure with said masonry product so that said face
surfaces form an exposed
surface;
applying a tinting composition by a single application to the exposed surface
of said masonry
product, such that said tinting composition colours said exposed surface and
maintains a look,
feel or texture of the masonry product
Preferably the Wet Area Method results in readings in the range of approx. 2
to 4 square
inches (12 to 24 square centimetres).
Preferably the Total Absorption Method results in total absorption times of
approx. 20 to
seconds
Tloe step of constructing said structure includes the laying of said masonry
product in a
25 stonework or brickwork fashion, with a mortar join between adjacent
individual masonry
products.
The mortar used can be of the same or similar reactivity to a face surface of
said masonry
product. The mortar can be struck so that it is finished flush with a face
surface of said masonry
product. The masonry product and the mortar can both be tinted with said
composition.
;0 Alternatively, the mortar can struck so that it is recessed relative to a
face surface of said
masonry product. By thls IlleallS the masonry product only will coloured with
said composition.
CA 02411329 2002-11-07
3
As an alternative, the mortar used can have a reactivity which will not absorb
said tinting
composition, when compared to the reactivity of said masonry product and will
not absorb said
composition. 'this mortar can be struck so that it is finished flush with the
face surface of said
masonry product. The masonry product and said mortar can be both coloured with
said
composition, with said mortar being washed, by water gun or other means, to
remove said
composition which has not been absorbed.
The masonry product can be a clay brick which is produced by means of applying
a
slurry at least to those surfaces of said brick which will be exposed when in
the structure to be
built from said brick, said slurry being fired with said clay brick in a kiln.
The slurry can be
to composed of water, fireclay, calgon or surfactant, glass cutlet or feldspar
or borax. The slurry
also include dried fine sand, or have dried fine sand applied thereto after
the slurry has been
added to the exposed laces of the brick..
The invention also provides a method of coating a masonry structure, said
method
including the steps of:
is testing reactivity of a masonry product as used in said masonry structure;
if the reactivity of the
exposed surfaces of the masonry structure is the equivalent of a wet out area
of 1 to 5 square
inches (6 to 34 square centimetres) by tire Wet Area Method as hereinbefore
defined or within IO
to 60 seconds by the Total Absorption Method as hereinbefore defined; applying
a tinting
composition by a single application to the exposed surface of said masonry
product, such that
z0 said tinting composition colours said exposed surface and maintains a look,
feel or texture of the
masonry product.
Preferably the Wet Area Method results in readings in the range of approx. 2
to 4 square
inches (12 to 24 square centimetres).
Preferably the Total Absorption Method results in total absorption times of
approx. 20 to
z5 30 seconds
In the method the masonry product and a mortar joint between adjacent masonry
products
can both be coloured with said composition. Alternatively, the masonry joint
between adjacent
masonry products can be insufficiently reactive so as to not absorb said
composition, but has
said composition applied thereto, with said mortar being washed to remove said
composition
3O which has not been absorbed.
~fhe method can include the step of modifying the reactivity of the exposed
surfaces of
said masonry product as used in said stnrcture, so that the modified
reactivity thereof is as
described above. This step of modifying the reactivity can include one or more
of the following:
CA 02411329 2002-11-07
4
pre-coating with a mineral paint based on a silicate chemistry of sodium or
potassium; the use of
absorbent sands in a concrete mix, and the use of light coloured cement, acid
washing such as
with muriatic acid, or innnersions being applied to the cured structure prior
to tinting in order to
open up the pore structure to produce the defined reactivity.
The present invention also includes a masonry structure being produced or
coated by the
above described methods.
The present invention provides a masonry tinting composition having as its
base an
acrylic latex or alkyd emulsion prepared for translucent application of colour
by means of
colourants, said composition further including colourant added in the range of
2 to 20 US ounces
to of colourant per US gallon of emulsion. The colourant can be an oxide with
colourant or an azo
dye or colourants synthesised to an organic compound that imparts colour under
visible light or
daylight.
There can be included a water repellent, this water repellent can be such as
that produced
by blacker Chcmic and bears product code BS 1306 or eduivalent. The water
repellent can be
15 present in the range of 10 ml to I 10 ml per US Gallon. The water repellent
and emulsion can be
homogenised by means of slowly adding the repellent to the emulsion, while the
emulsion is
being stirred which produces a mixing vortex in the emulsion. Other types of
appropriate water
repellent can also be utilised.
The composition can include a sun block compound. A sun block compound which
can
2o be used is that k1101b'll by the trade mark TINUVIN as manufactured by Ciba
Specialty
Chemicals Inc , and more specifically the product which bears the code TINUVIN
292 and or
TINUVIN 1130. The sunblock compound can be present in the range of 0.1% to 8%
by volume.
Other types of appropriate sunblock agent can also lie utilised in accordance
with manufacturer's
recommendations.
2s The composition can have a viscosity measured at 22 to 23 degrees Celsius
by means of a
Ford No 4 cup in the range of approximately 10 to 30 seconds, or of the same
viscosity as
measured by other means. More specircally the composition has a viscosity
measured at 22 to
23 degrees Celsius by means of a Ford No 4 crop in the range of approximately
12 to 1 S seconds,
or of the same viscosity as measured by other means.
3~> The composition can achieve the viscosity by means of dilution with water
in the range of
30°/, to 45%. More specifically the composition can be diluted with
water in the range of 35% to
40°,%.
CA 02411329 2002-11-07
A method of producing a masonry unil, said method including the steps of:
selecting or producing a masonry product having one or more face surfaces with
a reactivity
equivalent to a wet out area of approx 1 to 5 square inches (6 to 34 square
centimetres) by the
Wet Area Method as hereinbefore defined or within approx 10 to 60 seconds by
the Total
Absorption Method as hereinbefore defined; applying a tinting composition by a
single
application to the exposed surface of said unit, such that said tinting
composition colours said
exposed surface and maintains a look, feel or texture of the masonry product.
When the masonry unit is a clay brick it c;an be produced by means of applying
a slurry at
least to those surfaces of said brick which will be exposed when in the
structure to be built from
to said brick, said slurry being fired with said clay brick in a kiln, if the
clay from which the brick is
does not, after firing produce a face surface with the required reactivity.
The slurry can be
composed of water, fireclay, calgon or surfactant, glass Gullet or other
fluxes, or clay suspension
sources such as shales. The slurry can also include dried fine sand.
Alternatively the masonry unit can have the requisite reactivity after firing
or setting
without application of a slurry or pre-treatment.
Further the masonry unit Call pre-treated by means of one or more of the
following: pre-
coating with a mineral paint; the use of absorbent sands in a concrete mix;
the use of light
cement or acid etching or washing of the surface.
Multiple ones of said masonry units, or batches of said masonry units can have
said
zo tinting composition applied to exposed faces thereof in a single
application pass.
Through ollt t111S speClflCat10t1 and claims the word "masonry" will be
understood to
include brick, concrete, stone, fibre reinforced cement sheeting and other
masonry, unless
other<vise specified.
Detailed description of the embodiments and examples
z5 Example 9- Tinting composition:
The tinting composition is made from a base which is an acrylic latex or alkyd
emulsion,
such as that prepared for translucent application of colour via oxides or
colourants to substrates
such as wood, concrete, stone etc. Such a base can include the following
constituents:
CA 02411329 2002-11-07
6
Constituents Estimated Percent b
~ wei ht
_ 26.3
Acrylic Resin -'-
_Nuosept 95 _ _ 0.3 _
'
Nuocidc 404-D 0.7
_
Ne heline syenite G.O,~,-
Eth lone t:Tlycol 2.0
Cellulosic Thickener 1.5
Water ti3.2
The NUOCIDE 404-D & NUOSEPT 95 are proprietary preservatives made by
International Specialty Products Inc, and can be replaced by other similar
products.
Nepheline syenite is a "Flatting Pigment" and is available under the trade
mark MINEX
as manufactured by Unimin Specialty Minerals. The nepheline syenite can be
replaced by similar
anti-gloss or flatting pigment compounds.
Ethylene Glycol is present as a coalescing solvent and freeze-thaw agent. It
can be
replaced by similar products such as ~hEXANOL produced by ICI.
to Suitable characteristics for the base polymer emulsion for use in this
example, would be
those typical of base polymer emulsion of a premium wood stain:
To this base 10 ~JS oz per US gallon of oxide suspension with colourant is
added. If
desired as an alternative, 1 U US oz per gallon of organic colourant
suspension or paste colourant
t 5 could be added.
Thls COIIIpOSitloll is then shipped to the building site and then diluted by
35% to 40% of
water.
With such a composition the colour formulation does not need adjusting on site
and to a
limited extent, the colour formulation does not rely on the substrate colour
of the brick for its
20 fwnal colour.
CA 02411329 2002-11-07
7
Once applied to a masonry surface having the required reactivity, it is
expected,
depending upon ambient conditions at the time of application, that it will
take of the order of 5 to
30 minutes for the tinting composition to be de-watered and cross-linking
commencing whereby
acrylic latex bonding will have commenced.
s Example 2- tNater repellent tinting composition;
'To the base of Example 1 is added 70 millilitres per US gallon or an
estimated 0.4%
percent by weight of the composition of Wacker Chemie BS 1306 water repellent
which is mixed
through the emulsion. The water repellent and emulsion are homogenised by
means of stirring
the emulsion with an impeller on a rotating shaft so as to cause a mixing
vortex to be present in
to the emulsion, with the water repellent being trickle fed into the vortex to
produce an
homogenised product. This slow yet vigorous mixing will counter any
unfavourable volume
ratios and or viscosity gradients which might normally be encountered in such
dilutions.
T'o this hale l0 IJS oz per US gallon of oxide suspension with colourant is
added. If
desired as an alternative, 10 L1S oz per gallon of organic colourant
suspension or paste colourant
t 5 could be added.
This composition is then shipped to the bu lldrng site and then diluted by 35%
to 40% of
water.
With such a composition the colour formulation does not need adjusting on site
and to a
limited extent, the colour formulation does not rely on the substrate colour
of the brick for its
2o final colour.
The water repellent is an option in the tllltlllg composition and is added
only so that the
freestanding masonry or masonry exposed to the weather, after it has been
treated with tinting
composition, readily sheds water and is easier to clean and remains clean in
service. The blacker
Chemie BS 1306 is the preferred water repellent, but any appropriate water
repellent can be
25 utilised, in accordance with manufacturer's recommendations.
Example 3-Tinting composition with sunblock additive
To the composition of examples 1 and or 2, sun-blocking or UV absorbent
compounds
cal be added to give the applied composition sunblock capability to prevent
fading and increase
life.
3o A suitable sunblock or UV absorbing additive is sold under the trade mark
TINUVIN by
Ciba Specialty Chemical Ine . In particular Tinuvin 292 and Tinuvin 1130 are
preferred. The
amount utilised will be dependent upon the type and duration of protection
desired. The
CA 02411329 2002-11-07
g
manufacturer's recommendations can be followed. In the case Tinuvin 292 and
Tinuvin 1130 is
the total amount used can be between 2°o and 8% by weight of the
composition.
When adding UV absorbent additives which tend to have relatively high
viscosities, it is
important to ensure thorough mixing occurs in order to remove any viscosity
gradients which
s may otherwise result.
Example 4-another latex emulsion tinting composition
Another latex emulsion base, that is expected to give a similar result to that
described in
examples 1 to 3 above, has the following composition:
Constituents ~ ~ Estimated Percent
_ by
Res drol AY586_w/45o in wei ht
water 44.57
'
Mineral Spirits _ 3.87
~
Acrosolv DPM 3.06
_ _0_.41
Additol_VXW 6206 ~
~
-_-
-
-
Addita_l XL.25t)_ __1_.20
_
_
__
Tro~kya Anti skin B- _-_ 0.26
BYK 035 (I3yk Chemic~- _0.07
BYK 341 _ 0.30
_Troysan Pol base P20 T--' _0.85
Acrysal RM_8W --- 0.04
Acematt TS 100 D~ssa _ 0.83
Water 44.54
The Viscosity of this base is apprax 20 seconds on Ford No 4 cup
'1o this base 10 L1S oz per US gallon of oxide suspension with colourant is
added. If
desired as an alternative, 10 US oz per gallon of organic colourant suspension
or paste colourant
could be added.
t5 This base does not include any L1V absorbers and these can be added.
Measured viscosity data of the tinting composition
The viscosity of the tinting composition is an important factor for the
ability to apply the
tinting composition in a single application, to achieve the desired colour
density.
The data which follows are viscosity measurements of the tinting composition
of
2o Example 3, (Example 1 and 2 would achieve much the same results) using a
Ford No 4 cup at
22°C to 23°C, starting with one litre and adding Hz0 by volume
and recording the time for the
cup to empty:
CA 02411329 2002-11-07
9
Time to empty
Concentration (seconds)
~
Undiluted __ 27.7
Diluted b 100_m_1 water 20. 3
added
-Diluted by 200rn1 water __~_- 16. 6
added--'~
Di_lu_ted~300m1 water added- 15. U
,
Dilut_ed_by 400 ml water - 12. 3
added _
Di_lu_ted_by S00 rnl water_add_ed 12. 1
-Diluted. by 600 ml water 11. 7
added
-Diluted by 700 ml water 11.4
ad_decl
-Diluted 1y 1 OOOmI .waiter 11.1
added
- 09. S
pure water ~
As a comparison, paint was also tested and resulted in times of the order of
four
minutes to drain through the cup.
'the viscosity range required for the tinting composition of the examples
above are
achieved by means of a 35%-40% dilution with water and will result in a Ford
cup No 4
reading of approximately 12-15 seconds.
A reading of 50 seconds or greater would render the tinting composition
incapable of
penetrating the masonry surface and would thus give a painted or non-authentic
look.
A reading of 40 seconds would lead to overlap marks during application and
thus also
to not result in a suitable finish.
While the preferred reading is 12 to 15 seconds, a reading in the range of 10
to 30
seconds is thought to be able to produce desirable results.
The masonry surface to be tinted
The reactivity of a masonry surface ("reactivity" being a characteristic of a
surface
1~ which is a function of the porosity, the depth of pores, the structure and
interconnected
volume of those pores) is an indication of the; capillary action available to
absorb the tinting
composition. 'Ibis capillary action, if finite and restricted, will determine
whether the tinting
COIIIpOSltl011 Carl be applied as a single coat, and whether the tinting
composition will remain
in the masonry surface for a sufficient length of time. As to what may be a
sufficient length of
2o time will be discussed below.
The masonry surface to be tinted is bust if it is of a light colour and has a
pore depth,
structure and interconnected volume that mill accommodate one application of
the tinting
composition. 'fhe appropriate colour and reactivity will ensure that a masonry
surface will
react to floe tllltlllg composition in m even manner (not varying in colour
depth and thus not
CA 02411329 2002-11-07
l
patchy in appearance). The tinted surface will appear as authentic as the
original surface but
will simply have changed colour evenly, as the bulk, if not all, of the
tinting composition will
reside either within the masonry surface and/or below the masonry surface.
The masonry surface to be tinted can includes bricks, blocks or stones as well
as the
$ nt01'111~~Ulilf ifclesired, all of which can be coloured by the tinting
composition.
The IIVET AREA METHOD-a measure of the reactivity of a masonry surface.
While several tests could be used to identify the level of reactivity of a
masonry
surface, the following Wet Area Method has been found to be a most useful one:
Step 1: Orient a dry brick into a horizontal position with its face surface to
be tested facing up
at a location being at a room temperature of between 20°C and
25°C.
Step 2: Load 2 millilitres of water into a lab syringe, pipette or other
liquid measuring device.
Step 3: Discharge the 2 millilitres of water onto the centre of the brick face
surface within one
second.
Step 4: Measure and observe welting out/absorption behaviour of the brick
surface for one
15 minute from discharge of water onto brick face..
A non reactive surface, that is one which will not be suitable for use with
the tinting
composition in that it would not be satisfactorily recoloured in a one stage
absorption process,
will have water beading and sitting on top of the brick surface, with only a
relatively small
portion having been absorbed within one minute.
2o A suitably reactive brick surface, which would be suitable for use with the
tinting
composition and which will absorb sufficient composition in a single
application, will show a
markedly different absorption behaviour.
Preferably a suitable reactive surface will have the 2 millilitres of water
rapidly
wetting out the brick surface and spreading to an area of I to 5 square inches
(6 to 32 square
25 centimetres) or more preferably of 2 to 4 square inches (12 to 25 square
centimetres) visibly
wetting the brick face.
The TOTAL ABSORPTION METHOD-another measure of the reactivity of a
masonry surface.
A second test of the reactivity of a surface is called the Total Absorption
Method and
utilises steps I to 4 of the previous test, however, this test requires a
recording or noting of the
time taken to have the 2 millilitres of water completely absorbed by the
masonry surface.
CA 02411329 2002-11-07
For the purposes of this invention, a suitable reactivity is present if within
10 to 60
seconds and more prcferably20-30 seconds from the application of the 2
millilitres of water,
all of the water on the surface will have been absorbed into the masonry
surface with none
visibly remaining on the surface.
The Total Absorption Method and the Wet Area Method can be determined from one
procedure and do not have to be separately conducted.
Bricks and slurry compositions
Producing an appropriately reactive surface on a kiln fired clay bricks can be
done by
applying a tailored lireclay/ballclay kiln Erred slurry coating to external
brick faces.
to A full and even coverage of slurry is applied to the external faces of the
brick. Sand
can be incorporated in the slurry to bulk the slurry and aid as a parting sand
during
manufacture of the brick. This sand also adds to the reactivity of the slurry
surface as does
sawdust and similar materials, that creates extra pore volume and area by
inclusion in the
slurry composition.
The slurry surface can be adjusted, by means of changing the proportions of
the
contents of the slurry to accommodate more or less of the tinting composition
as is necessary
for different effects. Further, sand or other stable fillers can be added to
the slurry mixture so
as to create different surface effects after the tinting composition has been
applied.
Essentially and generally speaking, the slurry is an aqueous suspension of
fireclay and
2o water with a flux added (usually in the forni of Gullet and or feldspar).
In addition a dried sand
is incorporated into this slurry. This sand is added to aid in parting in the
production of a
conventional brick. The aqueous suspension is facilitated by the addition of
the dispersing
agent or suspension into the slur -y.
To achieve the desired results, the depth, reactivity and porosity of the
slurry is
z~ enhanced by deliberately adding more sand or increasing the rate of
application of the slurry
and applying a sprayed application of fine dried sand. The sand is
incorporated in the slurry as
it de-waters an the brick column during the extrusion process.
The ingredients of the slurry can include: fireclay; calgon or surfactant (to
aid
suspension of Creclay particles); glass cullett or mineral feldspar (to lower
the temperature of
3o forn~ation of ceramic bond of slurry to brick); water; dried fine sand.
No colorants or oxides are added to tl~e slurry as the tinting composition
provides the
colour.
CA 02411329 2002-11-07
12
The cullett level is reduced from standard levels to minimum requirements
whilst still
manufacturing a clay brick with a sound and durable fired slurry bonded to the
brick to
prevent the slurry from glassing up, which would otherwise decrease the
reactivity of the
resulting surface.
The slurry can be applied by any appropriate means, such as spraying from
stationary
or moving nozzles, application by brush, flooding by hose and spreading by
roller or other
appropriate method, over a moving brick extrusion column. Other bricks can
also be used
with suitably reactive coatings being applied such as bonded ceramic sand
coatings ( which
are a variation on a slurry or engobe) in soft mud moulded brick manufacture.
to The following are specific examples of suitable slurries:
The water in the above composition is varied to achieve a desired viscosity of
the agitated
homogeneous suspension. 'fhe viscosity of the slurry should fall in a range of
18-22 seconds
15 Ford Cup No. 4. The duantities are increased for the above slurry
composition at the same ratios
for bigger manufacturing runs.
In the formulation above there is no colorant added as the white is derived
from the
Kaolin clay, which can be purchased in bagged form.
The amount of flux is varied depending on the firing behaviour of the base
clay mix in
20 the brick and also kiln and kiln equipment limitations.
Instead of using kaolin other clays that form the suspension can be employed
depending
on availability and connnercial factors. These include but not are limited to:
ball clay; fire clay;
milled shales ( ball clays); milled clays; bagged ball clays; shales; kaolin.
These dry fine clays
are able to be incorporated in suspension. The choice might depend on the
colour required but
2s depend on the fired colour of tine ball clay or milled shale (or shale
blends).
The water is added to the suspension to vary the viscosity to the target value
for de-
watering and spreading purposes,
White coloured slurry formulation
CA 02411329 2002-11-07
13
Tlre dispersing agents used are surfactants that promote suspensions. These
include but
are not limited to: Calgon; Dispex.
The colourants arc added for effect and are usually inorganic glass body
stains. These
also include but are not limited to: ground colour imparting clays arid
shales; manganese dioxide
or manganous oxide; T iona. Ferro Corporation markets and sells most additives
for coloured
slurries.
The fluxing agents are used to bond the coating and a combination of: the
type; addition
levels; and the firing temperature that is employed to bond the slurry to the
brick, govern the
physical absorbency and also partly the reactivity to post colouration. These
fluxes include but
to are not limited to: glass cullct (ground); mineral feldspar powder;
shales/clays containing enough
natural fluxes; potassium and sodium carbonates. Generally it will be economic
considerations
that determine which flux is used.
Grey coloured slurry formulation.
Component-~__-_-- _ uantit
Local 1i Igpt coloured shale _ 1375 k~
Man anew Dioxide 18 k
Dispex ,-__,--~ 2litres
Water Approx 1000 litres
The target viscosity for tllis grey coloured slurry formulation is 13 secs for
Ford No 4 cup
IS test.
Another slurry formulation includes:
Light coloured slurry formulation
Com onent uantit
__~.L? _~.._
Ball C_la~y R 1300 k
~_---
Ceramic Glaze _235 k~g~-_
Frit'~
ffiona 35 k
_ 1.7 litres
I7ispex __-- _~
,
._._-'_- A pyrox 12001itres
Water
The target __ slurry formulation0 secs for Ford
viscos ity for this greyis 2 No 4 cup
coloured
test.
2o A further slurry formulation is:
CA 02411329 2002-11-07
14
Slurry formulation to receive tinting composition
Com onent --uantity
Kaolin 1300 kg
Cal on _ _2._2litres
Mineral Felds ar ~_ 15_0 k
Water A rox 1200 litres
Fine whitewashed sa_nd_ added to excess after slu dosin .
The target viscosity for this preferred slurry formulation is 21 secs for Ford
No 4 cup test.
This preferred reactive slurry is similar to those previously described but
has been
modified to be slightly more viscous and fill in its coverage. When it is
applied it has a feed rate
which is increased so that it is essentially flooding the extrusion column
surface. The excess
slun-y is mopped up evenly by a spray application ofthe fine dry white washed
sand.
The preferred slurry also differs in that the flux agent addition levels have
been lowered
so as to aid the absorption of the tinting compositions described above and to
also even out and
to minimise fired colour variations resulting from natural temperature
differentials. There are no
colorants added as none are necessary.
The flux selection and addition levels of the preferred slurry formulations,
as with
previous formulations, are tailored to the clay body of the brick and the
firing regime within the
kiln.
t s Concrete based masonry
For suitable concrete block, concrete roof tile and other masonry surfaces,
the tinting
composition can be applied with useful results if the masonry surface has been
modified via
an appropriate treatment that results in a level of reactivity which is
discussed above.
An appropriate pre-treatment can include pre-coating with a mineral paint, the
use of
?o absorbent sands in the concrete mix, applying an acid etching or washing to
open the pores
such as with muriatic acid, or immersions being applied to the cured. and the
use of light
coloured cements. These pre-treatments modify the masonry surface so as to
receive the
tinting composition as the pore structures will have been opened and the pore
depths will have
been limited to create the right site for a one stage colour absorption.
Zs Mortar joints
Mortar joints that are to be recoloured by the tinting composition need to be
specific
with regards to their mortar composition. The best mortar joints are
essentially a combination
CA 02411329 2002-11-07
of off' white or bright Portland cement and a suitable tight coloured sand (a
light coloured
sand is one that contains not too much clay or too little clay whether this
clay content occurs
naturally or it is added as required).
Where a "sharp" sand is to be used with a light Portland cement, it should be
modified
5 to make the mortar mix more workable and in doing so the dried mortar joint
will be
sufficiently reactive so as to take the colouring process in a one stage
roller application. The
sharp sand can be modified by adding either lime to the mix at approx S%-10%
addition
levels or by adding approx 5°/n-10'% of frreclay (also known as
"Brickie's clay").
Alternatively the ratio of cement to sand can be increased for example from
G:l to 4: 1 by
to volume with little or no addition of clay or hydrated lime.
The precise amount of fireclay required is determined by first conducting a
wet sieve
test washing the sand through a 45 micron sieve and determining the weight
loss on an oven
dried basis. The weight loss will be approximately the natural clay and silt
content of the
sand. Any shortfalls in the natural clay are topped up by the appropriate
addition of fireclay.
~ a Mortar finish details to receive the tinting composition
To properly apply the tinting composition to a mortar joint it should be cut
flush and
full with the brick/block edge for a monolithic uniform look where the mortar
colour matches
the brick/block colour.
If a non-monolithic look or traditional brickwork appearance with defined and
z0 contrasting mortar joints is required, then it will be best if the joint is
raked or recessed so that
the mortar does not come in contact with the tinting composition during the
application
process.
If desired, a non reactive mortar can be used and cut flush with the
brick/block. Such a
non reactive mortar may be produced by the addition of a bonding agent or
sealer. In this
case, by applying the tinting composition all over the brick/block and the
mortar, the tinting
composition will not adhere to the mortar and can be washed away by any
appropriate means
including by water gun or jet .
Application of the tinting composition
If the tinting composition is prepared as described above and applied by a
roller
3o having a l2mm to 20mm nap (with a l2mm nap being preferred) then the
tinting composition
of examples 1 to 3 does not overlap during absorption because it is drawn
below the masonry
sLrrfaCe.
CA 02411329 2002-11-07
The nap measurement of a roller is the pile length of the roller material.
While a roller is the most preferred application method, other methods, such
as
spraying or bruslring or other means can be utilised so as to achieve, by a
single application of
a tinting composition, onto a masonry surface having the reactivity as herein
defined, so that
S once tinted the masonry surface will have the look and or feel and or
texture of a masonry
surface. It is also believed that the masonry surface will maintain its
ability to breathe, maybe
not to the same degree as prior to tinting, because the tlntlng composition
will enter into the
pores of the masonry surface and coat (hem but not seal them.
Production of colour
to The tllltltlg COillpOSltiotl 1S 5llch that the final applied colour of the
tinted masonry, is
essentially designed from the colourants alone. While a light or white
background of the
llrLrSOtlry surface being tinted is helpful, the background colour recd not be
a factor.
Duration or life of the tinting composition
The level of sunblock compound added to the tinting composition will, together
with
is the reactivity of the masonry surface, determine the life of the tinting
composition as applied
to the masonry surface. While for some applications a life of 25 years is
desirable, in other
applications a life of 5 to 10 years will be desirable. For example, a home
owner may decide,
at the time of building, chat they will want to be able to change the colour
of the bricks and or
mortar, say at 1 () year intervals, and yet retain the look, feel, texture,
appearance of a brick
20 work surface. In this circumstance, the level of sunblock compounds added
can be varied to
achieve a desired life of the tinting composition.
In addition, the use of water repellents and UV absorbers or sun block
compounds for
interior applications on brickwork and masonry might be dispensed with
altogether.
Production of a masonry unit
2s A masonry unit, such a s brick or block, whether of fired clay or stone can
be
manufactured and delivered to a building site pre tinted by a tinting
composition.
Such a masonry unit can be manufactured whereby the unit is selected or
produced with
one or more face surfaces having a reactivity equivalent to a wet out area of
approx I to 5 square
inches (G to 34 square centimetres) by the Wet. Area Method as hereinbefore
defined or within
3o approx 10 to CO seconds by the 'total Absorption Method as hereinbefore
defined.
CA 02411329 2002-11-07
17
Unce the desired reactivity is present, a tinting composition can be applied
by a single
application to the exposed surface of said unit, such that said tinting
composition colours said
exposed surface and maintains a look, feel or texture of the masonry product.
When the masonry unit is a clay brick, if the clay brick when fired would not
have the
required reactivity, then before firing, it can nave a slurry, such as one
described above, applied
to the prick to at least to those surfaces of said brick which will be exposed
when in the structure
to be built (i~om the brick. Then the slurry can be fired with the clay brick
in a kiln.
Otherwise the masonry unit can have the requisite reactivity after firing or
setting without
application of a slurry or pre-treatment.
1o If the masonry unit does not have the required reactivity, then it can be
pre-treated by
means of one or more of the following: pre-coating with a mineral paint; the
use of absorbent
sands in a concrete mix; the use of light cement or acid etching or washing of
the surface.
'fo maintain a good rate of production the tinting composition can be applied
by means of
a spraying system.
~ 5 I3y this means the cost of production of the brick is expected to be
reduced by reducing
the complexity and reducing the costs of materials to produce a variety of
colour ranges.
A masonry unit produced by this method can then be used in construction in the
same
way as any other brick or block.
It will be understood that the invention disclosed and defined herein extends
to all
20 alternative combinations of two or more of the individual features
mentioned or evident from the
text. All of these different combinations constitute various alternative
aspects of the invention.
'fhe foregoing describes embodiments of the present invention and
modifications,
obvious to those skilled in the art can be made thereto, without departing
from the scope of the
present invention.
