Note: Descriptions are shown in the official language in which they were submitted.
CA 02281514 1999-08-19
WO 98/37145 PCT/SE98/00313
s COMPOSITION FOR COATING. SEALING AND PROTECTION PURPOSES
DESCRIPTION
Technical field
The present invention relates to a composition for coating, sealing and
protection purposes
to comprising an isocyanate curable polymer, a polymer curable isocyante, an
aliphatic polyether
glycol and rubber.
The basic object of the composition of the present invention is to obtain a
composition, which
can be used as a coating of surfaces, which are subject to corrosion, and
mechanical attacks;
15 as a sealing agent for water and other liquids at tube joints, roffing,
point-sealing of ceramic
tiles, metal sheets, and the like, and which composition is very resistant to
mechanical wear
and attacks by chemicals including water.
The object of the present invention is to obtain a fast prepolymerization of
part of the
2o isocyanate in order to avoid dripping and running of a sprayed or otherwise
applied
composition.
2s
A further object of the invention is to obtain non-settling properties of the
composition, as it
contains rubber particles which tend to settle upon storage.
A still further object is to obtain a non-moisture sensitive composition which
allows
application of the composition under moist conditions.
SE-A-7709649-3 describes a corrosion resistant coating composition,
particularly for external
3o rust protection of vehicle chassies, which composition consists of a
polyurethan polymer,
waste rubber, water free black coal tar, zeolitic drying agent. This
composition fulfills
generally its object, but has some disadvantages by strongly smelling of black
coal tar, which
prevents it from being used in more restricted spaces. and leads to that well
ventilated spaces
are required at the application, as well. Further, the black coal tar leads to
the fact that the
35 coating obtains a black colour, which often may not be of no importance,
but as often is not
acceptable, but one demands instead a pigmented product with a colour pigment
by choice.
Besides these drawbacks. which is of a certain cosmetic nature, one often
requires a still
higher wearing resistance, resistance against attack by chemicals,
particularly in alkaline
environment, and temperature stability.
The above problems are solved by a composition which contains rubber with a
particle size of
at most 0.4 mm, and present in an amount of at most 50 % by weight, and an
isocyanate
curable polymer base of the polyhydroxy type in an amount of 40-55 % by
weight, a polymer
curing isocyanate in an amount of 18-30 % by weight, and an aliphatic
polyether glycol in an
~ts amount of 1 to 5 % by weight.
Further characteristics are evident from the accompanying claims.
The curable prepolymer is preferably an isocyanate curable polyurethan
(DESVIODUR-
so hardener; DESMOPHEN 1150-prepolymer) but also isocyanate curable epoxy
polymers can
be used.
CONFIRMATION
COPY
CA 02281514 1999-08-19
WO-98/37145 .. PCT/SE98/00313
Suitable binding agent of polymer type which are curable by isocyanate active
hardeners are
different poIyols, polyester bases, having a molecular weight of 200 and more.
Other polymer
materials are epoxy resins which are primarily dissolved in a keton, or a
glycol ether, and are
then cured using an isocyanate active hardener {e.g. DESMODUR) or amino group
active
hardener. Suitable epoxy resins have a molecular weight of 1000 or more.
The aliphatic polyether glycols used can either be a polyester, such as
DESMOPHEN 1150, or
the like, and/or an aliphatic glycol, or more simple, such as ethylene glycol,
diethylene glycol,
triethylene glycol.
All types of rubber can be used as a rubber material, such as waste rubber,
waste rubber tires,
raw rubber, and other rubber qualities.
Thus it has turned out that 20-40 % by weight of rubber powder, suitably waste
rubber, having
a particle size of <0,4 mm, preferably 0.05-0.2 mm, 40-50 % by weight of a
polymer base, 1-5
% by weight of an aliphatic poIyether glycol base, and 18-25 % by weight of an
isocyanate
hardener give excellent products within the scope of the present invention.
Thus these
compositions have, in cured state, a very high elasticity, and wearing
resistance. In the case
the polyester base contains moisture a zeolite drying agent should be added,
alternatively
active aluminium oxide, or basic aluminium silicates.
The object of the present invention is achieved by adding a cycioaliphatic
amine in an amount
of 0.1 to 1.0 % by weight of the total composition.
Hereby a rapid prepolymerization is obtained within seconds after application
of the total
3o composition to a surface, thereby eliminating running and dripping of the
composition from
the surface treated.
In a prefferred embodiment the cycloaliphatic amine consists of 3,3-dimethyl-
4,4-
diaminodicyclohexyl methane present in an amount of 0.1 to 1.0 % by weight of
the total
composition, preferable in an amount of 0.3 to 0.7 % by weight.
The cycloaliphatic amine reacts with part of the isocyanate present and
provides a rapid
increase of the viscosity, before the isocyanate and the isocyanate curable
polymer react to
form the final coating.
In order to achieve non-settling properties of the composition stored the
composition may
further be made thixotropic by the addition of a Soya bean derivatitive. The
soya derivative is
present in an amount of about 0.5 % by weight of the total composition.
~t5 In a further object of the present invention the composition is made non-
moisture sensitive,
the isocyanate-polyurethane system being sensitive to moisture, by the
addition of a water
absorbing agent such as an aluminum silicate, a zeolite, whereby the
composition can be
applies even in moist areas without risk of foaming, the water absorbing
material is added.
when desired. in an amount of ~-10 % by weight depending upon the moist
conditions, such
5o as present in a concrete mass when sealing e.g. road and bridge
constructions.
CA 02281514 1999-08-19
WO 98/37145 " PCT/SE98/00313 _
EXAMPLE 1
40 parts per weight of waste rubber having a particle size of 0.1 to 0.2 mm
were intimately
mixed with a mixture of 39.5 parts per weight of DESMOPHEN 1150, and 2 parts
per weight
of poiyether glycol (triethylene glycol) as well as 0.5 parts per weight of
3,3-dimethyl-4,4-
diaminodicyclohexyl methane. To this mixture I8 parts per weight of an
isocyanate active
t o hartener (DESMODUR) were added for the curing of the polymer at the
application of the
total composition to an object, such as surface of concrete or metal.
A product of Example 1 above (A) was tested and compared with a product (B) of
SE-A-
7709649-3, the Example, with regard to wearing resistance, heat resistance,
adherence to
t 5 steel, and chemical resistance.
Wearing resistance
Plates with applies coatings of above were handled in a tumbler for 5 days
(120 hrs) together
with 200 g of stones. The volume of material having been worn off, given in
mm', was then
20 measured.
A= 19 mm'
B=10~ mm'
z5 Cylindrical test bodies of the respective product were forced over an emery-
cloth having 60
particles per cm~ with a pressure of 5 N, and length of 20 m, whereupon the
volume worn off
was determined.
A=14~ mm'
30 B=470 mm'
Heat resistance
Plates with applied coating were hanged vertically for 2 days (=l8 hrs) at
different
temperatures, the samples/plates were then acclimatized to ambient temperature
(20° C),
35 whereupon they were checked ocularly.
A= withstand 1 SO ° C
B= withstand 80 ° C
4o Adherence to steel
Coatings on steel were tested for traction for determining the adherence
ability.
A= withstand 4.0 Mpa prior to burst
B= withstand 0.8 Mpa prior to burst
Chemical resistance
Test coatings of the respective products were subjected to different oils,
whereby one could
generally determine that sample B miscoloured all such liqiuds, while sample A
did not give
any miscolouration. At testing in acidic aquoes environment (HCL 30%; HNO3
10°,'°; H,_ SO,
10%: or CHjCOOH 50%) the resistance is just about the same. In an alkaline
aqueous
environment (NaOH or NH, OH) sample A is better.
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WO 98/37145 PCT/SE98/00313 _
4
The water vapour permeablility is less for sample A than it is for sample B.
Application
Sample A can be applied in thicker layers (2.5-3 mm) on vertically hanging
testing plates
compared with sample B which allows 1.5 mm, only.
to
Runnin
The composition of the invention was applied onto vertically hanging metal
sheets in a layer
having a thickness of 1.5 mm and was compared with a composition (B) being
applies with
the same layer thickness, I .5 mm. The running of the two compositions was
determined by
simply measuring the movement of the lower edge of the applies area.
A= 0.5 mm
B= 10 mm
2o Thus the addition of the cycloaliphatic amine improved the nonrunning
properties
considerably.
In connection with the preparation of the present composition one should
preferably put the
product under vacuum, whereby, in particular, the wearing resistance, and the
chemical
resistance are further improved. Furthermore, the aging resistance, moisture
resistance, and
the traction strength are improved. The pressure in the vacuum step for
elimination of air
should be 0.8 bar, but can in case of very high viscous compositions be
further reduced down
to 0.5-0.6 bar.
Application of the composition can be effected in different ways, such as by
means of simple
manual painting, by mechanical painting, as well as by means of high pressure
spraying. At
high pressure spraying a modified conventional high pressure spraying
apparatus of two-
component type is suitably used. wherein the composition, exclusive of
hardener, and
hardener are brought together prior to the outlet of a mixing tube (mixer) and
is brought
forward to a spraying gun via a heat taped high pressure hose. The pressure on
the
composition shall be so high that a well distributed spraying mass is obtained
(atomized),
which, at viscosities of the composition normally appearing, is obtained at
160-200 k~/cm=
and a temperature of >40° C, preferably 40-80° C, more
preferably 45-60° C.
Normally the viscosity of the composition is such that the high pressure pump
as such does
not manage to draw the composition into the apparatus as normal temperature.
Thus, a
pressure plate has been arranged to the high pressure spray apparatus, with
success, which
plate fits snuggly into the vessel where the composition is prepared,
whereupon the pressure
plate is pressed down into the preparation vessel either mechanically,
pneumatically, or
hydraulically, so that the composition is pressed up into the high pressure
spray apparatus.
In order to increase the curing of the composition above an accelerator of the
curing reaction
can be added in an amount of 0.1-0.5 % by weight. Exemples of such
accelerators are dibutyl
distannium dilaurate, or corresponding lead compounds.
CA 02281514 1999-08-19
W0 98/3'1145 PCT/SE98/00313
-
5 In order to reduce the fire risk a flame retarder can be added to the
composition such as a
phosphite compound. which is added in an amount of 5-15 % by weight. Nowgard V-
4 is an
example of a retarder.
The composition can be made thixotropic as well, by adding a suitable jelling
substance.
i5
25
35
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