Note: Descriptions are shown in the official language in which they were submitted.
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PROPEI,LANT-SOLVENT SYSTEM FOR WATER;BASED P~INTS
The present invention relates to aerosol paint
compositions, and in particular to a novel propellant-
solvent system therefor.
Aerosol paint compositions are well known but have
used volatile organic solvents as the carrier for the film~
forming polymer. Toxicity and flammability problems arise
from the use o~ such organic solvents and governmental
regulatory authorities are moving towards severe restric-
tions on the use of organic solvents in such compositions.
In our Canadian Patent No. 1~102,466, we have
described a water-based aerosol paint formulation which
satisfactorily produces a high gloss and excel~ent durability
paint film on a substrate surface. The compositions
15 defined therein are restricted to a narrow range of film- -
forming polymers.
It has now surprisingly been found that a novel
single phase propel].ant-solvent composition can be utilized
to form satisfactory spray-applied films based on a wide
variety of water-dilutable film-foxming polymers, which may
be in solution form or emulsified Eorm. The novel propel-
lant composition of this invention consists essentially of:
(a) about 20 to about 75~ by weight of dimethyl ether,
(b) about 10 to about 50% by weight of water,
(c) about l to about 30~ by wei~ht of at least one
aliphatic monohydric alcohol of the formula: R-OH wherein
R is an unsu~stituted straight or ~ranched chain alkyl
group containing from l to 6 carbon atoms, and
(d) about l to about 15~ by weight of at least one
coalescing solvent. The proportions of the components total
100~ and are sufficient to provide a single phase.
While the present invention is primarily directed to
the provision of aerosol paint compositions, nevertheless
the propellant-solvent composition may be used for the spray
dispensing of a variety of other active components, such as,
in hair sprays and deodorants.
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The essentlal components of the propellant composition
of this invention are dimethyl ether, water, an aliphatic
monohydric alcohol and a coalescing solvent. Dimethyl ether
is a colorless, odorless, stable molar liquid with a boiling
point of -25C and a vapor pressure of 4.2 bar at 20C.
It has been previously suggested to use this liquid as
a propellant. U.S. Patent No. 1,800,156 discloses the use
of dimethyl ether alone as the propellant for a large variety
of materials and paints are mentioned. U.S. Patent No.
3,207,386 discloses the utilization of a combination of
dimethyl ether and water as a propellant for a wide variety
of products including paints, the proportions being chosen
to provide a homogeneous solution of the dimethyl ether and
water as the propellant and this restriction results in a
composition consisting of 5 to 35% by weight of dimethyl
ether and 95 to 65% by weight of water. No other solvent
or propellant components are used in this prior art compo-
sition.
In the present invention, the dimethyl ether is used
in a combination with water, alcohol and coalescing solvent
to provide a single phase propellant-solvent composition
for a water-dilutable film-forming polymer which is in aque-
ous solution or aqueous emulsion orm, and hence the present
invention involves quite a different application of the
dimethyl ether in different proportions for a different p~se.
The dimethyl ether constitutes about 20 to about 75~
by weight of the propellant-solvent composition, preferably
about 25 to about 40% by weight, typically about 40~ by weight.
Another essential component of the propellant compo-
sition o~ the invention is water. This component is presentin a concentration of about 10 to about 5Q% by weight,
preferably about 20 to about 35% by weight, typically
about 30% by weight.
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A wa-ter-soluble lower aliphatic monohydric alcohol
also is used in the composition. The monohydric alchols
used in this invention are those having the formula: R-OH
wherein R is an unsubstituted strai~ht or branched chain
alkyl group containing from l to 6 carbon atoms. Examples
of suitable monohydric alcohols are methanol, ethanol, n-
propanol, iso-propanol and n-butanol, prefera~ly ethanol
or iso-propanol.
The concentration of the monohydric alcohol used in
the compositions of this invention may vary widely from
about l to about 30% by weight, preferably about 5 to about
20% by weight, typically about 15% by weight.
The fourth essential component of the composition is
a water-soluble coalescing solvent. A coalescing solvent
is one which assists in coalescence of the polymer into a
uniform and continuous coating on the surface onto which a
paint composition formulated using the composition of the
invention is sprayed.
The coalescing solvent may be any water-soluble
organic solvent which is also slow to evaporate. Such
materials include glycols, glycol ethers, esters and
certain modified alcohols and generally have a boiling
point in the range of about 365 to about 572F. (about 185
to about 3Q0C). Suitable solvents include lower monoalkyl
ethers of ethylene or propylene glycol, such as, propylene
glycol methyl ether and propylene glycol methyl ethyl
ether, diacetone alcohol and ester alcohols.
The coalescing solvent is present in an amount of
from about l to about 15% by weight, preferably about 5 to
about 10% by weight, typically about 6% by weight. The
combination of the monohydric alco~ol and coalesciny solvent
is present in an amount of about 2 to a~out 30% ~y weight
and, in combination with the chosen proportions of
dimethyl ether and water forms a single phase composition
which is suitable for dissolvin~ or suspending the active
components to ~e dispensed.
The propellant-solvent composition o~ the invention
exerts a vapor pressure when packaged in a pressurized
container sufficient to effect dispensing of the contents
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of the container~ Generally, the vapor pressure is in the
range of about 30 to about 85 psig at 70F, and preferably
about 40 to about 6Q psig.
The dimethyl ether constitutes the propellant compon-
ent of the composition. The water provides the primarysolvent and/or suspension phase for the active components,
which include a film-forming polymer in the case of an
aerosol paint. The aliphatic alcohol and the coales-
cing solvent mainly act as solvents for the propellant and
the water, so that there results a substantially sin~le
phase mixture of components, which resists separation into
separate liquid phases on standing. A single phase propel-
lant-s~lvent composition enables active components to be
readily and efficiently dispensed from the aerosol container.
The propellant-solvent composition of this invention
has particular utility in the provision of aerosol water-
based paint compositions. Such compositions comprise the
single phase propellant-solvent composition and a film-
forminy polymer dissolved and/or suspended in the propellant-
solvent composition. Pigments also may be included to
impart pigmentation to the sprayed film.
Such water-based aeroso~ paints generally comprise
about 6 to about 25% by weight, pr/3ferably about 12 to about
20% by weight, of the film-forming polymers and about 92 to
25 about 75% by weight, preferably about 88 to about 80% by
weight, of propellant-solvent and, optional components,
such as, pigments, surfactants, stabilizers, antifoam agents
and plasticizers, as discussed in more detail belo~.
The propellant-solvent composition is quite versatile
30 and is effective to permit the spray application of a wide
variety of film-forming polymers onto a substrate surface to
form a continuous film of excellent durability, including
high flexibility retention. Depending on the nature of the
polymer and the other components of the formulation, the
35 films may be of high gloss, medium gloss, low gloss or flat.
Aerosol compositions formulated using the propellant-
solvent system of the composition are non-flammable, as
tested according to standard flammability tests for aero-
sols. For example, the spray ~lows out a candle.
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The film-forming polymer may be any water-soluble or
water-dilutable emulsified polymer which is capa~le of spray
application to form a continuous film on a substrate surface.
~any classes of polymer may he employed, including acrylic
resins, alkyds, epoxy esters and polyvinyl copolymers.
Acrylic resins are thermoplastic or thermosetting
polymers or copolymers of acrylic acid, methacrylic acid,
esters of these acids, or acrylonitrile. Such resins may
be modified by the presence of an aromatic monovinylidene
compound, usually, styrene. Acrylic resins generally have
molecular weights in the range of about 100,000 to about
1,000,000.
One example of an acrylic resin which is suitable for
the formulation of a water~based aerosol paint composition
in accordance with this invention is available from Rohm
and Haas Inc~, under the designation "W.L. 91". Another
example is the resin available from Reichold Chemicals
under the designation "90-587 Resin".
Alkyd resins are made by combining dibasic acids
or their anhydrides, usually phthalic anhydride, with a
polyhydric alcohol, such as glycerol. Alkyd resins often
are modified by natural drying oils, such as, linseed oil,
soya oil and safflower oil, in concentrations of 30 to
60~ by weight.
Examples of alkyd resins which are suitable for the
formulation of a water-based aerosol paint composition in
accordance with this invention are available from Ashland
Oil Inc., under the Trademark "AROLON" such as those
designated "580" and "585".
Epoxy ester resins are resins containing a reactive
epoxy group and derived from polyols and epoxy-group
containing compounds. Other comonomers, such as, styrene
may be copolymerized. These resins may be modified by
natural drying oils in the same manner as alkyd resins.
An example of an epoxy resin which may be used is sold by
~eichold Chemicals under the designation "38-690".
Polyvinyl copolymers are formed by copolymerizing
vinyl chloride or vinyl acetate with copolymerizable
monomers. One example of s~ch a material suitable for the
.
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formulation of a water-based aerosol paint composltion in
accordance with this invention is available from B.F.
Goodrich Company under the designation "514H".
Mixtures of two or more resins or resin types may be
used in the aerosol water-based paint formulations of this
invention.
As mentioned above, an optional component which may
be present in the paint composition is a pigment for pigmen-
tation of the film formed on spraying the composition onto
a substrate surface. When employed, up to about 15% by
weight of the total composition of the pigment may be used,
preferably about 5 to about 15% by weight of pigment.
When such pigment is present, the quantity of polymer
used is generally towards the lower end of the range recited
above. When such pigment is omitted and a clear film is
required, then quantities of polymer towards the higher end
of the range are used.
The presence of the pigment usually requires the
presence of added surfactant to ensure suspension of the
piyment in the liquid vehicle. Some surfactant may be
present with the film-forming polymer, if the latter is in
emulsion form, but the quantity involved usually is
insufficient to effect suitable suspension of added pigment.
The overall quantity of surfactant present in the
composition should be sufficient to maintain solids in
suspension and usually varies up to about 3% by weight of
the composition~
A pH stabilizer may also be present in the composition
to provide an overall p~I value greater than about 7.2 and
3~ up to about 10 to assist in inhibition of corrosion of the
conventional pressurized metal container in which the paint
composition is located for spray application. Suitable pH
stabilizer materials include morpholine, ammonia and
triethanolamine. This component may be present in an
3~ amount of up to about 2% by weight of the total composition.
An antifoam agent may be included to alter the
surface tension of the composition to penmit ready release
of dissolved gases upon spraying of the composition onto
the substrate surface and to counteract the detergent
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effect of the surfactants present in the composition. A
non-ionic blend of mineral oils and silica derivatives has
been found to be suitable for use for defoaming. When an
antifoam agent is present, quantities up to about 2% by
5 weight of the total composition may be used, preferably
about 0.4% by weight.
Another component which may be added to the aerosol
paint composition i5 a plasticizer to promote flexibility.
Any one of a wide range of plasticizers may be used, for
10 example, dioctyl phthalate. The plasticiæer may be
present in an amount of up to a~out 2% by weight of the
total composition, preferably about 1% by weight.
The aerosol water-based paint compositions provided
in accordance with this invention, therefore, are character-
15 ized by a pH of about 7.2 to a~out 10, preferably about 7.4
to about 7.~, and consist essentially of:
about 6 to about 25 wt.% of at ]east one water-
dilutable film-forming polymer(calculated as the non-
volatile content thereof),
about 20 to about 60 wt.% of dimethyl ether,
about 10 to about 40 wt.% of water,
about 1 to a~out 20 wt.% of at least one aliphatic
monohydric alcohol containing from 1 to 6 carbon atoms,
about 1 to about 10 wt.% of at least one coalescing
solvent,
0 to about 3 wt.~ of at least one surfactant,
O to a~out 15 wt.~ of at least one pigment,
0 to a~out 1 wt.% of at least one pH stabilizer,
0 to about 2 wt.% of at least one antifoam agent, and
0 to about 2 wt.% of at least one plasticizer.
The dimethyl ether, water, monohydric alcohol and
coalescing solvent are present in the composition in pro-
portions to provide a single phase solvent-propellant system
in which the remainder of the components are dissolved or
suspended.
The aerosol water-based paint composition, which is
formulated as described above using the propellant-solvent
system of the invention, may be sprayed onto a substrate
surface without foaming occurring and the pigmented or
unpi~mented continuous film touch dries rapidly, usually in
about 15 to 30 minutes, and exhibits complete water
resistance in an acceptable period of time, usually in
about 3 to 5 hours.
The invention is illustrated by the f~ winy
Examples:
Examples 1 to 13
A number of aerosol water-based paint formulations
were prepared using various film-forming polymers and
pigments and packaged in aerosol cans. The films were
sprayed onto substrate surfaces. In each case, a continuous
film was formed which was dry to the touch in 30 minutes,
exhibited water resistance within 3 hours of application and
15 had a salt spray resistance (ASTM test B117) of more than
50 hours.
The following are the ~ormulations:
Example 1 - Red oxide primer - Mixed acrylic-epoxy resin
Component wt.%
20 WL91 Resin (-) 3.6
38-690 Resin~2) 14.5
Water 13.25
Isopropyl alcohol 15.0
Butylcellosolve 4.0
25 Texanol * 0-7
Red Oxide pi~nent 5.0
Driers - Mn 6%, Co 6%0.25
L475 (3) 0.2
Triethanolamine 1.0
30 Dioctyl phthalate 0.5
OK412(4~ 2.0
Dimethyl ether 40._0
Total 100.0
Notes~ Acrylic resin made by Rohm and Haas;
35 (2) Epoxy resin made by Reichold Chemicals;
(3) Defoamer - Dow Chemical;
(4~ Silica flattening agent.
* - Trademark
Example _ - Blue - Acrylic resin
_mponent _wt.%
WL91 Resin 22.0
Water 10.0
Isopropyl alcohol 15.0
Butylcellosolve ~.5
Texanol 0.7
White pigment 2.3
Blue pigment 4.6
L475 0.2
5% NH40H 0.2
Dioctyl phthalate 0.2
Dimethyl ether 40.0
Total 100~0
Examples 3 to 7
Formulations similar to Example 2 were prepared using
WL91 as the resin with differing pigments, as follows:
Example 3 - White
Example 4 - Red
Example 5 - Green
Example 6 - Black
Example 7 - Orange
Example 8 - Flat black - Acrylic resin
Component wt.%
WL91 Resin 21.8
Water 9.5
Isopropyl alcohol 15.0
Butylcellosolve 4.5
Texanol 0.7
Black pigment 5.0
L475 0.4
5% NH40H 0.5
Dioctyl phthalate - 0.5
OK412 2.0
Triton X-45( ) 0.1
Dimethyl ether 40.0
Total100.0
Note: (1) Rohm ~ Haas non-ionic surfactant
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Example 9 - Fire orange fluorescent - Acrylic resin
ComPonent wt.%
90-587 Resin~ ~ 15.0
Water 12.7
Isopropyl alcohol 15.0
Butylcellosolve 4.0
Fire orange pigment 11.7
L475 0.2
NH40H (conc.) ~.3
Triton X 405( ~ 0.1
Dimethyl ether 40.0
Total 100.0
Notes: (1) Reichold Chemicals acrylic resin;
(2~ Rohm & Haas nonionic surfactant.
Example 10 - Red oxide primer - Alkyd-Acrylic resin mixture
Component wt. %
WL91 Resin 18.00
Arolon 585(-) 5-75
Water 15.03
Isopropyl alcohol 15.00
Butylcellosolve 4.50
Texanol 0.70
Red oxide pigment 8.00
L475 0.40
5% ~H40~I 0.02
Dioctyl phthalate 0.50
OK412 2~00
Triton X100 0.10
Dimethyl ether 30,00
Total 100.00
Note: (1) Ashland Oil alkyd resin
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Example 11 - Blue - Alkyd resin
Component _ wt. %
Arolon 580 (1) 27.0
Arolon 585 ( ) 10.2
Water 8.8
Isopropyl alcohol 7.7
Butylcellosolve 2.3
slue pigment 2.1
l~hite pigment 1.1
Drier 0,3
L475 0.2
5% NH40H 0.1
Triton X100- 0.3
Dimethyl ether 4~.0
TotallQO.O
Note~ and (2) Alkyd resins made by AshIand Oil
Example 12 - Red Oxide primer - Epoxy resin
In the formulation of Example 1, the WL91 resin was
replaced wholly by an increased amount of 38-690 resin to
provide 18-1 wt.~ of such resin in the resulting formulation.
Example 13 - clear ~ PVC resin
Component wt. %
415H Resin( ) 25.0
Water 24.7
Isopropyl alcohol 15.0
Butylcellosolve 5.0
L475 0.2
5% Ammonia 0.1
Dimethyl ether 30.0
Total 100.0
Note: (1) Carboxy modified polyvinyl chloriae terpolymer
made by B.F. Goodrich.
SUMMARY OF DISCLOSURE
In summary of this disclosure, the present invantion,
therefore, provides a novel propellant~solvent composition
useful for the spray application of water-based paints to
substrate surfaces. Modifications are possible within the
scope of this invention.
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SUPPLEMENTARY DISCLOSIJR~
In the principal disclosure, there is described a
single phase propellant-solvent (or active carrier) composition
consisting essentially of:
(a) about 20 to about 75% by weight of dimethyl ether;
(b) about 10 to about 50% by weight of water;
(c) about l to about 30~ by weight of at least one
aliphatic monohydric alcohol of the formula: R-OH wherein R
is an unsuhstituted straight ox branched chain alkyl group
10 containing from 1 to 6 carbon atoms;
(d) about l to about 15% by weight of at least one water-
soluble coalescing solvent, the composition exerting a vapor
pressure within the pressurized container in the range of
about 30 to about 85 psig at 70F.
It has now been found, in accordance with this
Supplementary Disclosure that, although it is pre~erred for
the alcohol and coalescing solvent to be present in the
recited pr~portions and to use dimethyl ether as the sol~
propellant, there may be provided a single phase propellant-
20 active carrier composition consisting essentially of:
(a) about 20 to about 75~ by weight of a propellant com-
~ising dimethyl ether and from 0 to about 50% by weight o~
the dimethyl ether of another liquid propellant;
(b) about 10 to about 50~ by weight of water; and
(c) about 0.1 to about 45~ by weight of at least one
water soluble polar organic solvent. The proportions of the
components total 100% and are sufficient to provide a single
phase. The composition, together with auxiliary gaseous pro-
pellants, if present, exerts a vapor pressure in a pressurized
30 aerosol container in the range of about 30 to about 85 psig
at 70F, preferably about 40 to about 60 psig.
Suitable liquid propellants which may be used along
with the dimethyl ether are aliphatic hydrocarbons and
fluorinated hydxocarbons. Suitable auxiliary gaseous phase
35 propellants which may be used along with the dimethyl ether,
with or without the other liquid propellants, are nitrogen,
carbon dioxide and nitrous oxide.
Among the polar organic solvents which may be used
A are alcohols, glycol ethers, esters, ketones and certain
13
modified alcohols, examples of which are specifled in the
principal disclosure.
The propellant-active carrier composition may be
used ~o provide water-based paint compositions. Such com-
5 positions are preferably substantially non-flammable, as tested
according to standard flammability tests for aerosols~
Suitable water-dilutable film-forming polymers which may be
formulated with the propellant-active carrier composition
are described in detail in the principal disclosure.
In accordance with this supplementary disclosure,
the aerosol water-based paint compositions are characterized
by a pH of about 7.2 to about 10, preferably about 7.4 to
about 7.9, and consist essentially of:
about 6 to about 25 wt.% of at least one water-
15 dilutable film-forming polymer (calculated as the non-volatile
content thereof),
about 20 to about 60 wt.% of a propellant comprising
dimethyl ether and 0 to about 50~ by weight of the dimethyl
ether of another liquid propellant,
about 10 to about 40 wt.% of water,
about 0.1 to about 30 wt.~ of at least one watex-
soluble polar organic solvent,
0 to about 3 wt~ of at least one surfactant,
0 to about 15 wt.~ of at least one pigment,
0 to about 1 wt.~ of at least one pH stabilizer,
0 to about 2 wt.% of at least one antifoam agent,
and
0 to about 2 wt.% of at least one plasticizer.
The propellant, water and polar solvent are present in the
30 composition in proportions to provide a single phase
propellant-active carrier system in the remainder of the
components are dissol~ed or suspended. Suitable surfactants,
pigments, pH stabilizers, antifoam agents and plasticizers
are described in detail in the principal disclosure.
The invention is illustrated further by the
following addïtional Example:
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14
Exam~le 14
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wt.,~,
Sty:renated epoxy ester (1) 13 . O
Water 31. 0
S White t~rlter ( ~ ) 13 . 5
Driers ~Cu naphthenate 69~,
~ naphthenate 6~ ) 0 . 2
Acti~7e 8 0.1
Co~cant~ated ammonia 1. 0
Byk 020 (defoamer) 0. 2
By}c 351 (flow age~t)1. 0
Dimethyl ether 40 0
otal 100. 00
~otes: (1) 453~t8 by C~P.V. - comprises 70% solids and 3096
Butylc~llosc~Lve
( 2 ) T~rltar comprise : Styrerlated er~ y ester 23 ~ 5
Cor~c~ntrated ammonia 1. 5
Wate2 15 . O
TiO 60 . 0
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