FIELD OF INVENTION
This invention relates to an organosilicone resin emulsion composition.
Further, this invention also relates to use of above emulsion for
preparation of corrosion resistance coating on steel substrate.
BACKGROUND OF THE INVENTION
In the paint and coating fields, it is lately required from the standpoint,
of avoiding environmental pollution and maintaining a safe working
environment, to change the dispersing media from organic solvents to
aqueous media. To meet the requirement, emulsion type coating
compositions are widely utilized as the base material of coating
compositions because of their firm formability and chemical resistance.
The coating compositions of this type, however, have the drawback that
they are essentially less resistant to water and weather. On the other
hand, silicone resins which are obtained through hydrolysis and
condensation of silane compounds draw attention as coating
compositions because they are able to form films having a high hardness
and exhibiting good properties including weather resistance, water
resistance, heat resistance and water repellency. However, the emulsion
polymerization process of obtaining silicone resin by polymerizing
monomers in emulsion has not been established. As the general rule,
silicone resin solutions are prepared in organic solvent systems such as
toluene and xylene and then emulsified without isolation. Instability is
one problem associated with these organic solvent-containing silicone
resin emulsions. In addition, the environmental concern requires to
control the use of organic solvents such as toluene and xylene.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention is to provide an
organosiloxane resin emulsion composition which has good corrosion
resistance, weather resistance, and stable and free of environmental
problems.
It is a further object of this invention to provide an organosilicone resin
emulsion composition which can be uniformly coated on steel surfaces.
Another object of this invention is to provide an organosilicone resin
emulsion composition which is resistant to saline atmosphere.
These and other objects of the invention will be apparent to a reader on
reading, the ensuing description in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig 1: shows the particle distribution in emulsion prepared from methyl
hydrogen siloxane.
Fig 2: shows the zeta potential value at different pH of emulsion prepared
from methyl hydrogen siloxane.
Fig 3: shows the TG/DTA curve of coating prepared from methyl
hydrogen siloxane emulsion.
Fig 4: shows the DSC curve of coating prepared from methyl hydrogen
siloxane emulsion.
Fig 5: shows the corrosion performance of the coatings.
DESCRIPTION OF THE INVENTION
According to this invention is provided an organosilicone resin emulsion
composition comprising:
(A) 100 parts by weight of an organosilicone resin having the
chemical name methyl hydrogen siloxane
(B) 1 to 25 parts by weight of a water-miscible emulsifier
(C) 0.5 to 50 parts by weight of a non ionic surfactant, and
(D) 25 to 2,000 parts by weight of water
According to this invention is further provided an article coated with the
organosilicone resin emulsion composition comprising:
(A) 100 parts by weight of an organosilicone resin having the
chemical name methyl hydrogen siloxane
(B) 1 to 25 parts by weight of a water-miscible emulsifier
(C) 0.5 to 50 parts by weight of a non ionic surfactant, and
(D) 25 to 2,000 parts by weight of water
In the composition according to the invention, an organic solvent other
than the water miscible emulsifier and the non-ionic surfactant are
substantially absent. By 'substantially absent' is meant not only the
situation where the composition does not contain an organic solvent
other than the water miscible emulsifier and the non-ionic surfactant,
but also the situation where the composition is substantially free of an
organic solvent other than the above mentioned components, i.e. the
composition may contain insubstantial or trace amount of organic
solvents that do not affect the safety or create environmental problems.
For example, the composition may contain organic solvents other than
the water miscible emulsifier in amounts of up to 0.5-3% by weight,
preferably up to 2% by weight, more preferably up to 1% by weight,
based on the weight of the total organic solvent.
The emulsifier is selected from compounds such as a polyoxyethylene
alkyl ether, a polyoxyethylene propylene alkyl ether, a polyoxyethylene
alkyl phenyl ether, apolyopxyethylene fatty acid ester, an alkysulfate, an
alkylbenzenesulfonate, an alkylsulfosuccinate, an alkyiphosphate, a
polyoxyethelene alkyl ether sulfate, a polyoxyethylene alkyl phenyl ether
sulfate, a quaternary ammonium salt, an alkylamine acetic acid salt, an
alkyl betaine, and an alkyl imidazoline or their derivatives.
The surfactant is a non-ionic or anionic surfactant selected from
compounds such as a polyoxyethylene alkyl ether, a polyoxyethylene
propylene alkyl ether, a polyoxyethylene alkyl phenyl ether, a
polyoxyethylene fatty acid ester, an alkysulfate, an
alkylbenzenesulfonate, an alkylsulfosuccinate, an alkyiphosphate, a
polyoxyethelene alkyl ether sulfate, a polyoxyethylene alkyl phenyl ether
sulfate, a quaternary ammonium salt, an alkylamine acetic acid salt, an
alkyl betaine, and an alkyl imidazoline or their derivative.
The orgaosilicone resin emulsion composition is used for preparing
corrosion resistant coatings. The chemical composition of the corrosion
resistant coatings is methyl hydrogen siloxane emulsion

The adhesion promoter is selected from compounds such as silicon
modified acrylic resin and/or silicon modified derivative.
The leveling agent is selected from silicon modified acrylic resin and/or
silicon modified derivative.
The flash rust inhibitors are selected from compounds such as sodium
nitrite, benzotriazole, a mixture of several inhibitors, its composition is as
follows:
10-25% of C12-C14 (2-benzothiazolylthio) succinic acid tert amine
salts
10-25% of ethoxylated tridecylalcohol phosphate-comprising
monoethanolamine salts
10-25% of zinc salts of branched (C6-C19) fatty acids
<2.5% of zinc salts of naphthenic acid
10-25% morpholine benzoate
The nano pigments is a compound selected from zinc oxide, silica,
alumina, cerium oxide or any combination thereof and water used for all
these processes is demineralised water.
The silicone emulsion is prepared by mixing continuously, methyl
hydrogen, siloxane, emulsifier, surfactant and water in the given
proportions with stirring, at a speed of 400 to 600 rpm at a temperature
in the range of room temperature to 45°C, slowly adding water thereto,
while stirring at a speed of 2500 to 4000 rpm for 20 to 90 minutes, to
obtain the silicone emulsion. The emulsion particle size and zeta
potential are analysed by malver particle size analyzer.

The corrosion resistant coating composition is prepared by mixing the
ingredients in the given proportion, with stirring at a stirring speed of
2000 to 3000 rpm for about 4 hrs at room temperature, to form the
coating composition. The above prepared coating is applied on a steel
substrate by dipping process, at room temperature, followed by drying at
100 to 200°C for about 20 min to 2 hours.
In applying the organosilicone resin emulsion compositions of the
invention to substrates, any of well-known coating methods such as
dipping, spraying, roll coating and brush coating may be employed.
Although the coating weight of the organosilicone resin emulsion
composition is not particularly limited, it is usually coated so as to give a
coating thickness of 0.1 to 1,000 micron, especially 1 to 100 micron after
drying.
The invention will now be explained in greater detail, with the help of the
following non-limiting examples.
EXAMPLES
Methyl hydrogen siloxane emulsion is prepared by mixing the following
ingredients at a mixing speed of 500 rpm at room temperature,
Methyl hydrogen siloxane 15 gms
Emulsifier 2 gms
Surfactant 0.05 gms
This is followed by slowly adding water (83 gms) to the mixture with
stirring at 3000 rpm for about 60 minutes.

The corrosion resistant coating is prepared by mixing the followings
ingredients at a speed of 2000 to 3000 rpm for 4 hours at room
temperature. This coating was applied on a steel substrate by dipping the
substrate in the coating composition for 1 min at room temperature,
followed by drying at 150°C for 30 min to 1 hrs at the rate of 10 to 20°C.
The coating microstructures, phases, coating elements were analyzed.
Corrosion performance of this coating in saline atmosphere was
investigated.
Particle size analysis of sol:
Particles sizes of the optimum sol were analyzed by Zitasizer. It was
found that 95% particles are below 10 nm in size. This is shown in Fig:
2. This nano particle size emulsion will provide a high volume fraction
coating and at low coating thickness it is possible to get a dense,
compact and uniform coating which will helpful to give good corrosion
resistance properties.
TGA/DTA analysis of powder to find phase transformation temperature:
This prepared coating was dried at 150°C for 30 - 60 min to obtain
powder particles. The powders were analyzed by TG/DTA to see its
thermal behavior. Fig. 3 shows the relative mass loss by TGA and
differential thermal analysis (DTA) curves corresponding to the dried
powders sample. There is a slow and static degradation of sample, even
after 700°C tested sample undergoes only 34.55% weight loss. After
700°C there is no more weight loss and remains constant till 1000°C.
Presence of small exothermic peak at around 100° C indicates about the
evaporation of weakly associate water molecule. Sharp exothermal peak

at 413°C and 743°C are due to the degradation and decomposition of
organic compounds present in sample. After 700°C there is no more
decomposition takes place. Due to this high thermal resistance behavior,
developed coating can be exposed at high temperature (up to 300°C)
Coating performance: SST was carried out to see its corrosion resistance
properties. It was found that coated steel is giving 300-400 hrs SST
resistance as compared to 2 hrs in case of bare steel.
Further, the organosilicone resin emulsion compositions may be used as
a base polymer in adhesives and when combined with other organic
resins or silane coupling agents, form adhesives which are effective for
establishing a bond between substrates of different materials.

WE CLAIM:
1. Organosilicone resin emulsion composition comprising a 5 to 50
gms of methyl hydrogen siloxane, 0.1 to 25 gms of an emulsifier,
0.1 to 25 gms of a surfactant, and 25 to 200 gms of water.
2. The composition as claimed in claim 1, wherein the emulsifier is
selected from the group consisting of a polyoxyethylene alkyl ether,
a polyoxyethylene propylene alkyl ether, a polyoxyethylene alkyl
phenyl ether, apolyopxyethylene fatty acid ester, an alkysulfate, an
alkylbenzenesulfonate, an alkylsulfosuccinate, an alkyiphosphate,
a polyoxyethelene alkyl ether sulfate, a polyoxyethylene alkyl
phenyl ether sulfate, a quaternary ammonium salt, an alkylamine
acetic acid salt, an alkyl betaine, and an alkyl imidazoline or their
derivatives.
3. The composition as claimed in claim 1, wherein the surfactant is a
non-ionic or anionic surfactant.
4. The composition as claimed in claim 1, wherein the surfactant is
selected from the group consisting of a polyoxyethylene alkyl ether,
a polyoxyethylene propylene alkyl ether, a polyoxyethylene alkyl
phenyl ether, a polyoxyethylene fatty acid ester, an alkysulfate, an
alkylbenzenesulfonate, an alkylsulfosuccinate, an alkyiphosphate,
a polyoxyethelene alkyl ether sulfate, a polyoxyethylene alkyl
phenyl ether sulfate, a quaternary ammonium salt, an alkylamine
acetic acid salt, an alkyl betaine, and an alkyl imidazoline or their
derivative.

5. A process for the preparation of an organosilicone resin emulsion
as claimed in claim 1 comprising mixing continuously
methyl hydrogen siloxane 5 to 50 gms
emulsifier 0.1 to 25 gms
surfactant 0.1 to 25 gms and
by stirring at a speed of 400 to 600 rpm, at room temperature, to
45°C and slowly adding water while stirring the mixture at a speed
of 2500 to 4000 rpm for 20 to 90 minutes, to obtain the
organosilicone resin emulsion.
6. A corrosion resistant coating composition for a steel substrate
comprising
Organosilicone resin emulsion 5 to 95 gm
Adhesion promoter 0.01 to 15 gms
Levelling agent 0.01 to 15 gms
Flash rust inhibitor 0.1 to 50 gms
Nano pigment 0.1 to 15 gms
Water 5 to 90 gms
7. The coating composition as claimed in claim 6, wherein said
adhesion promoter is selected from silicon modified acrylic resin
and/or silicon modified derivative.
8. The coating composition as claimed in claim 6, wherein said
leveling agent is selected from silicon modified acrylic resin and/or
silicon modified derivative.
9. The coating composition as claim 6, wherein said flash rust
inhibitor is selected from products like sodium nitrite,
benzotriazole, a mixture of several inhibitors, its composition is as
follows:
10-25% of C12-C14 (2-benzothiazolylthio) succinic acid tert amine
salts
10-25% of ethoxylated tridecylalcohol phosphate-comprising
monoethanolamine salts
10-25% of zinc salts of branched (C6-C19) fatty acids
<2.5% of zinc salts of naphthenic acid
10-25% morpholine benzoate
10.The process as claimed in claim 6, wherein said nano pigments is
atieast a compound selected from zinc oxide, silica, alumina,
cerium oxide.
11.The process as claimed in claim 6, wherein water is demineralised
water.
12.The coating composition as claimed in claim 6 wherein an acrylic
resin emulsion, urethane resin emulsion is used with the organo
silicone resin emulsion.
13.The coating composition as claimed in claim 12, wherein the
organosilicone resin emulsion is present in 10 to 90% by weight of
the mixture.
14.A process for the preparation of the corrosion resistant coating
composition as claimed in claim 6, comprising mixing
Organosilicone resin emulsion 5 to 95 gms
Adhesion promoter 0.01 to 15 gms
Levelling agent 0.01 to 15 gms
Flash rust inhibitor 0.01 to 50 gms
Nano pigments 0.01 to 15 gms
Water 5 to 90 gms
at a stirring speed of 200 to 3000 rpm for about 4 hrs at room
temperature to form the coating composition.
15.A process for coating a substrate with coating composition as
claimed in claim 6, comprising applying the coating composition
on a substrate, and drying the coated substrate at 100 to 200°C
for 20 min to 2 hours.
16.The process as claimed in claim 15, wherein coating is effected by
methods such as dipping, spraying, roll coating and brush coating.
17.The process as claimed in claim 15, wherein the substrate is
coated to give a coating thickness of 0.1 to 1000 micron, and 1 to
100 micron after drying.

This invention relates to organosilicone resin emulsion composition
comprising a 5 to 50 gms of methyl hydrogen siloxane, 0.1 to 25 gms
of an emulsifier, 0.1 to 25 gms of a surfactant, and 25 to 200 gms of
water.