Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a paint composition
and a method of applying this paint composition to a concrete base.
Among the methods for applying paint to a concrete base,
brush-coating and spray-gun methods are well-known. Before paint
is applied to a concrete base with a brush, the surface of the
base is pretreated usually by being polished by a grinder in order
to remove unevenness or irregularities thereon and then the base
is coated with mortar or putt~, further smoothed by sand paper,
and treated with a sealer primer. Then an undercoat, second coat
and final coat of paint are generally applied to the pretreated
surface of the base with a brush. When a spray-gun is used, the
surface of the base is cleaned and the unevenness and irregulari-
ties are removed; pin holes are plugged, and a sealer primer is
applied to the surface of the base before the under coat and final
coat of paint are applied with the spray-gun.
However, the known methods of coating concrete involve a
number of complicated processes, and much time and labour are re-
quired for their practice. In particular, when hydraulic cement is
sprayed with a spray-gun at a low temperature, efflorescence tends
to take place, which cannot be avoided. Furthermore, considerable
skill is required for spraying paint with a spray-gun, and there
is usually a considerable amount of paint wasted. If, instead of
expensive proper scaffolding, hanging-type scaffolding is construc-
ted for paint-spraying of buildings, operational difficulties
are increased and uneven application of paint tends to occur.
It has now been discovered, according to the present
invention, that certain novel paint compositions which dry at
ambient temperature, have short curing times, and do not crack
or separate from the substrate after application, can be applied
directly to concrete bases without subjecting the bases to any
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pretreatment. Further, it is possible to apply these paint com-
positions in one step to give thick films thereof, which films
only need to be finally coated with a protective material.
The surfaces which are coated with these paint composi-
tions are suitable for indoor or outdoor use, and exhibit superior
resistance to fading and weathering. Further, the coated surfaces
have a glossy, ceramic appearance similar to that of ceramic tiles,
and present no health hazard to humans coming into contact with
them. Moreover, these coated surfaces can be repeatedly washed
with water with virtually no variation in colour.
According to the present invention, there is provided a
paint composition comprising a mixture of (a) Portland cement,
(b) from 100 to 150 parts by weight of an aggregate, (c) from 1 to
3 parts by weight of calcium chloride, (d) from 0.4 to 2 parts by
weight of naphthalene sulfonic acid formalin condensate, and (e)
from 1 to 2 parts by weight of alkylcellulose, all of the parts be-
ing based upon 100 parts of the Portland cement.
The paint composition of the present invention is
usually prepared by adding to a mixture of Portland cement and an
aggregate, in any order, 1-3 parts of calcium chloride, 0.4-2
parts of a naphthalene sulfonic acid formalin condensate, 1-2 parts
of an alkyl cellulose, all of said parts being by weight per 100
parts by weight of the Portland cement. Further, it is possible
to add to the composition at least one additive such as a dry pre-
ventive agent, shrink prevention agent, efflorescent prevention
agent, waterproofing agent, defoaming agent, coloring agent,
and water. The resulting mixture is then processed into a paste.
The paste can be applied by means of a porous hand roller to the
surface of a concrete basP in one step to give a mastic coating.
The expression "dry preventive agent" as used herein
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means a hardener which serves mainly to retard evaporation of
moisture in the paint composition.
The calcium chloride present in the composition serves
to accelerate the curing of the paint composition.
Examples of the alkyl cellulose are either methyl cellu-
lose or ethyl cellulose. The alkyl cellulose desirably has a high
gel point, preferably above 90C.
It is preferable to use, as the naphthalene sulfonic
acid formalin condensate, the sodium salt of ~-methyl naphthalene
sulfonic acid formalin condensate.
Examples o additives which are introduced into the mix-
ture are 2-5 parts of propylene glycol as a dry preventive agent,
0.5-10 parts of calcium sulfoaluminate (3CaO. 3A12O3. CaSO4) as a
shrink prevention agent, 5-15 parts of zeolite as an efflorescence
prevention agent, 0.1-5 parts of calcium stearate as a waterproof-
ing agent, and 0.01-0.2 parts of tributyl phosphate as a defoaming
agent, as well as a suitable amount of a ~olouring agent, all of
the parts being by weight, based upon 100 parts by weight of the
Portland cement.
It is possible, according to a preferred aspect of this
invention, to add a synthetic rubber latex such as styrene-
butadiene rubber or a vinyl resin emulsion such as a copolymer of
acrylic acid or an ester thereof to the above-described paint
composition, as this generally produces a film of more uniform
quality and strengthens the bond between the finishing coat and
the film formed of the paint composition of the present invention.
Further, if such a vinyl or acrylic acid or ester copolymer paint
is applied as a finishing coat to the above-mentioned composition-
coated base, the resulting layer provldes excellent protection as
well as an aesthetically pleasing appearance.
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The method of the present invention differs from the
ordinary roller painting method in which the paint composition
which comprises finely divided white lime stone is applied with a
brush roller to the surfaces of a porous base.
0 The method of the invention is also dif~erent from rollerapplication of a sandtextured coating, in which the aggregates
mixed in the composition are apt to form agglomerates or fly about,
causing extensive loss of the composition during application and
giving rise to uneven finishes.
In order to achieve a satisfactory mastic coating using
the prior compositions, it is usually required to apply the paint
composition several times, which results in the production of
thick coating layers which tend to crack during drying.
The method of the present invention overcomes the dis-
advantages of the conventional methods. The present method can be
easily practiced by using, for example, a porous hand-roller with
which the paint composition of the invention is pressure-transfer-
red to the surface of a base at the rate of from 1.3 to 2.4 kg/m2;
no special skill is required for this.
An example of a suitable porous hand roller for carry-
ing out the present invention is one made of polyurethane foam
produced according to U.S. Patent 3,171,820. This roller is made
of reticulated foam which is obtained by hydrolysis of specially
treated sponge followed by removal of the resulting film and has a
3-dimensional network structure. The U.S. Patent describes (at
column 1) the structure of the foams as "novel reticulated poly-
urethane foams". At column 2, lines 38-58, it is stated that the
foams can be used in the fabrication of insulating materials but
~ there is no mention of the possibility of employing the foams for
P 30 rollers for coating paints and the like. It has been found ~ha~
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rollers made of these foams having a 3~dimensional network struc-
ture are particularly suited for putting the present invention
into practice since they can absorb a substantial amount of paint.
In ~able 1, the work efficiency obtained by the method
of the invention is compared with that of known methods of spray-
ing a hydraulic cement and spraying a sand--textured paint composi-
tion.
Table 1
Spraying Spreading Work
Method Times of rate 2 rate 2 ef~iciency
coatin~ (kg/m ) (kg/m ) (m /man-day)
Method of pre-
sent invention 1 1.3-1.8 1.2-1.7 60-70
Spraying of a
hydraulic cement 2 1.2-1.3 0.8-1.0 60
Spraying of a sand-
textured paint 2 0.7-1.7 0.5-1.2 ~5
Composition
It has been observed that the surfaces o~ the spray
finished concrete base usually become dirtier with time, whereas
the surfaces of the concrete base treated by the method of the
invention, are only slightly contaminated even after 2 years and
6 months; the small amount of contamination which does accumulate
can be readily removed by washing with water.
Generally, the properties of the coating depend on where
the coat is applied, for example to walls or to ceilings of a
room, or indoors or outdoors.
It is particularly desirable for outdoor coatings to have
good weather resistance, water resistance, adhesion, cleanliness,
and rigidity. Indoor wall coatings should have good adhesion, water
resistance and rigidity, and ceiling coatings should possess good
adhesion and water resistance as well as an attractive appearance.
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~47~86
he method of the present invention is particularly
suitable for producing coatings for indoor or outdoor use. The
films formed, after being allowed to stand ~or 28 days, have sur~
faces exhibiting a glassy uneven appearance similar to the surfaces
of ceramic tiles, and such films are not only decorative but also
cover any irregularities and pinholes on the surface of the ba$e.
The maximum thickness of the film prepared with the
paint composition of the invention is usually from 2 to 3 mm, and
its properties are given in Table 2.
Table 2
Item Results o the test Te~ting method or kind
of etandard empIoyed.
1. Proce~sability Good A porou~ hand roller
was employed in co-
ducting the test.
2. Condition o~ Good Uni~ormity and ~tabi-
coating film lity of the patterns
pre~ented by the film
and uniformity o~ its
color.
- 3. Impac-t re~ist- No chænge at 1 kg JIS-A-5403
-ance (on 28 day- x 75 cm
old film)
20 4. Adhe~ion More than 3 k ~cm2 An adhesion tester
(Under normal kept at the Architect-
condition) ural Re~earch Institute
of the Ministry of Con-
~truction wa~ employed
in conducting the test.
5. Abra~ion test 95 mg/l,000 time~ Taber~ abra~ion test-
(on 28 day- er. (Abraoer: H 22,
old ~ilm) load: 250 g)
6. Wa3hability No change after JIS A 6909
being wa~hed 2,000
time~.
7. Degree of lu~t- More than 70 JIS-K 5400
er
8. Freeze thaw No change after 20 In accordance with
~tability cycles. ASTM C-290-61T
9. Water penet- Quantity of water JIS-A 6101 2
30ra-tion (on 28 penetrated: None Water pre~sure: 0.1 k~/cm
day-old fil~)
10. Accelerated No ehange after IrIadiation by a
weathering 1,000 hour~ weathermeter
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The invention is further illustrated by the following
examples. Parts and percentages are by weight.
Example 1.
65 parts of water were added to 100 parts of a paint
composition consisting of the ingredients stated below in Table
3, and the resultant mixture was kneaded into a pa,ste, which was
then applied at a rate of 1.8 kg/m2 to surfaces of a 315 m2 indoor
concrete wall of a ply-wood form. After the lapse of 2~ hours (tem-
perature: 20C, relative humidi~y: 65%), a 25~ toluol solution of
an acrylic ester copolymer was applied at the rate of 0.45 kg/cm2
to the film of the so-prepared paint composition. A coating having
a glassy uneven finish resulted similar to the finish of ceramic
tiles, which covered the irregularities of 2-3 mm and pinholes on
the surface of the base. No cracking or peeling off of the covering
paint was observed. The work efficiency was 65 m2/man-day. The
adhesion of the film to the base was measured at 10 kg/cm2 under
normal conditions after the film had been allowed to stand for
28 days. The film was 3.0 mm thick and not permeable to water.
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Table 3
Inyredients of the ~aint composition of Example 1
Item Kind ~ by weight
Cement Hydraulic white Portla~d cement 100
Aggregate Silica sand (100-200 mesh)100
Pigment Anatase titanium dioxide 10
Zeolite (efflorescence preventive 10
agent)
Calcium chloride 3.0
Naphthalene sulfonic acid formalin 1.2
condensate*
Additives Calcium stearate 0.5
Calcium sulfoaluminate (antishrink- 1.0
ing agent)
- Methylcellulose (4000cp)~* 1.0
Tributyl phosphate 0.1
Proplyene glycol 2.0
* Tradename: Nopcosant (Nopco Chemical).
** Tradename; ~ethocel (Dow Chemical).
The viscosity of the methylcellulose in Tables 3 and 4 was
measured as a 2% aqueous solution at 20C.
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Example 2
To 100 parts o~ a paint composition consisting of the
ingredients stated below in Table 4 were added 70 parts of water
and 20 parts of 46% acrylic ester copolymer emulsion. The mixture
was kneaded into a paste. The paste was applied at a rate of
2.0 kg/m2 to a 101 m2 outdoor concrete wall of a metal form which
had not been pretreated. After the lapse of 24 hours, (temperature:
20C, relative humidity: 65%), white enamel (solid content: 40%)
in a toluol solution of an acrylic ester copolymer w~s applied
to the film, prepared of the paint composition, at the rate of
0.4 kg/m2. A glassy uneven finish resulted similar to that of
ceramic tiles, which covered the pinholes on the surface of the
concrete base. No cracking or peeling off of the coating paint
was observed. The worlc efEiciency was 70 m2/man-day. The film
of the so-prepared paint composition possessed properties similar
to those shown in Example 1. The addition of the polymer emulsion
to the paint composition helped to produce a film of uniform
quality and to improve the adhesion of the film to the finishing
material.
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Table 4
Ingredients of the paint composition of Example 2
. . .
Item Kind ~ by weight
i
Cement Hydraulic white Portland cement 100
.. . . _ .
Aggregate Silica sand (100-200 mesh) 150
Pigment Anatase titanium dioxide 10
-
Zeolite 12
Calcium chloride 2.0
Naphthalene sulfonic acid formalin 1.5
condensate*
Calcium stearate 0.5
Additives
Calcium sulfoaluminate 1.2
Methylcellulose (4000 cp)** 1.5
Tributyl phosphate 0.1
Propylene glycol 4.0
* Tradename: Nopcosant (Nopco Chemical).
** Tradename: Methocel (Dow Chemical).
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