Note: Descriptions are shown in the official language in which they were submitted.
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PCT991240
1
"POLYMER COMPOSITION FOR MANUFACTURING SELF-ADHESIVE FIGURES"
FIELD OF THE INVENTION
The present invention is related to the technique for the manufacture of
figures that adhere to surfaces, and more particularly, it is related with a
polymer
composition for manufacturing self-adhesive figures.
BACKGROUND OF THE INVENTION
For long time, the use of both two-dimensional or three-dimensional figures
has been the instrument that, expositors, teachers, speakers and any person
who speaks
in public or exposes some particular topic to other persons, have been used as
support to
complement their expositions.
t 5 Generally, such expositions occur in places where there are supporting
means based on flat surfaces, such as blackboards, folio boards, communication
boards,
slides, etc.
Similarly, this kind of figures are also used as signs or indicators for
different graphics, agendas and controls on blackboards, maps or graphs which
have to
zo be considered by several persons in organizations.
The main problem that manufacturers of this kind of products face has
been the way to make the figures to adhere to flat surfaces.
Nowadays, this problem has been solved by the use of magnetic figures,
for which the flat surface on which the figures will be stuck is required to
be metallic. The
25 material of which the figure is made does not matter, as far as a magnet or
a magnetic
material can be placed on it or the figure itself is manufactured with
magnetic material.
As mentioned before, said figures, in order to function, require that the flat
surface on which the figures will be stuck be metallic and with magnetic
properties in such
a way that a magnetic field between the figure and the surface is established,
thus making
3o the adhesion possible. It is important to emphasize that the fact that the
surfaces should
have magnetic properties increases the manufacturing cost, as in the case of
magnetic
blackboards.
On the other hand, there is a system of symbols in the market that is used
in conferences or expositions, that uses a material known as Velcro to adhere
to flat
:>5 surfaces. As it is widely known, Velcro works using two substrata, where a
first
substratum includes a plurality of hooks and a second substratum opposite to
the first
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2
one, which contains threads or fuzz that will fasten to the hooks. The
inconvenience of
this system based on Velcro is that the surface intended to place the figure
can not be
written due to the material's rough surface.
Another method for the adhesion of figures is the one that employs paper
made figures. The figure incorporates on one of its surfaces an adhesive
substance from
the so called open - cycle adhesives, which do not form a permanent adhesion
of the
paper with other surface but provide enough strength to maintain the figure
adhered for a
while. The inconvenience that presents this method is that the adhesive
substance easily
looses its adhesive capacity, which confers to the figures a very short useful
lifetime.
~o Likewise, it is possible to find other figures that adhere by means of
other
adhesive agents, which have the disadvantage of not been removable, or of
leaving stains
on the surface on which they were adhered once they are removed.
Similarly, there can be found self-adhesive figures made of different
materials that have as adhesive system a sucker or suction pad which allow the
figures to
t ~ remain adhered to a smooth surface due to the principle of the suckers.
This system has
the disadvantage that the figure, due to the sucker, is considerably separated
from the
surface on which the figure was adhered, besides having a short lasting
adherence.
There are also figures that can be placed on surfaces by means of insertion
systems, such as grooved boards on which letters or symbols are inserted, in
restaurants
?o or building directories, or Pike the marquees of cinemas and theatres.
As it may be observed, most of the methods of adhesion or fastening for
figures or symbols on surfaces require two parts: one figure, that has a
special
characteristic that allows the fastening, or as well, that incorporates some
device such as
a magnet, sucker or Velcro; and a surface that presents the characteristics
required to
_ 25 permit the adhesion in accordance to the device employed, i. e. surfaces
with magnetic
properties, grooved surfaces, or as well, adequate surfaces for Velcro.
Additionally, the adhesion systems and the figures described above have
the inconvenience of not letting to observe what is behind them.
On the other hand, polymer compositions based on polyvinyl chloride,
denominated
3o plastisoles, have been known and used for a long time. A typical
composition of plastisol
includes a polyvinyl chloride resin, a plasticiser and a stabilizer in
proportions that permit
the processing of the same for the manufacture of diverse figures such as
toys, scholar
erasers, ornaments far pencils, tool coatings, etc.
It is widely known that by means of the addition of an excess of plasticizer
3 ~ agent, it is possible to obtain the adherence of a plastisol after cured,
since the plasticising
agent is trapped by the polyvinyl chloride resin in order to be subsequently
exuded.
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3
Nevertheless, the plastisol compositions of this type that have been used for
the
manufacture of toys, are not adequate for the manufacture of figures for
systems of signs,
because the useful lifetime of the same is very short due to the easy
adherence of dust to
the composition, preventing the subsequent adherence of the figure, besides
having a
jelly consistency due to the excess of plasticizes, making it not so adequate
to use.
Additionally, exudation of the plasticizes agent causes the surface on which
the plastisol was placed to be stained once the figure is removed, which
represents a
great inconvenience for the manufacture of self-adhesive figures for systems
of signs.
Consequently, for long it has been sought to overcome the inconveniences
to of prior art self-adhesive figures, by providing a polymer composition for
manufacturing
self-adhesive figures which allows manufacturing and obtainment of self-
adhesive figures
that require only a flat surface to adhere, besides being easily handled and
having the
most diverse shapes to be used in a large quantity of applications,
additionally having a
long useful lifetime and the characteristic that the composition of which the
figures are
t 5 made does not leave stains when they are removed.
OBJECTIVES OF THE INVENTION
Having in mind the defects of the prior art, it is an object of the present
2o invention to provide a polymer composition for manufacturing self-adhesive
figures that,
once formed, require only a flat surface in order to adhere.
Another object of the present invention is to provide a polymer composition
for manufacturing self-adhesive figures which permits that the figures
obtained have any
shape and presentation (opaque, transparent, fluorescent, phosphorescent,
regular,
?5 irregular, etc), without requiring additional materials.
One other object of the present invention is to provide a polymer
composition for manufacturing self-adhesive figures which permits to obtain
figures with a
long useful lifetime which do not leave stains on the surfaces on which they
are adhered
once they are removed, and having an adequate consistency for their handling.
DETAILED DESCRIPTION OF THE INVENTION
It has been unexpectedly found by means of laboratory tests, that the
polymer composition based on polyvinyl chloride of the present invention,
permits to
obtain self-adhesive figures which have the characteristic of adhering to flat
surfaces
without requiring such surfaces to have an additional characteristic for the
adhesion, but
PCT99I240
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4.
due to the combination of the elements of the composition, the mentioned
figures can be
placed on the surface and removed afterwards to be used again without leaving
stains on
the surface and having a consistency adequate for their handling.
Among the materials on which it is possible to adhere such figures, it can
be mentioned, as an enunciative but not restrictive way, the following: glass;
metal;
melamine; acrylic; wood, paint; ceramic; acetate; mica; polymeric materials;
or, any other
kind of material that allows to offer a flat, non-porous surface.
The polymer composition, based on polyvinyl chloride, object of the present
invention,
belongs to the group of polymers known as plastisoles, which can be handled in
liquid
Icy form, and subsequently be cured or hardened to finish the polymerization
of the polyvinyl
chloride.
The composition of the present invention basically comprises a polyvinyl
chloride resin, a first plasticizer agent, a second plasticizer agent and a
stabilizing agent
that avoids the degradation of the polyvinyl chloride resin; which, when mixed
in certain
! 5 specific amounts, produce a synergistic effect that allows the obtainment
of adequate
adhesive properties for a good performance of the figures.
In a preferred embodiment, the polymer composition contains diverse chemical
compounds traditionally used in the industry of plastisoles. In has been found
unexpectedly that it is possible to obtain the required adhesion properties in
the figures for
?ti systems of signs only by means of the use of a composition including
approximately from
35 to 60% by weight of resin polyvinyl chloride; approximately from 37 to 64%
by weight of
the first plasticising agent; approximately from 0.5 to 1.5% by weight of the
second
plasticising agent; and, approximately from 0.5 to 1.5% by weight of the
stabilizing agent.
Additionally, it has been found that if an exudation adjuvant agent is further
?5 added in a range from 3 to 25% by weight, approximately, in respect to the
total weight of
the composition not including the adjuvant agent, the properties of the same
are be
improved, thus obtaining self-adhesive figures with even more useful lifetime
and better
adherence.
If no pigment is added to the composition, the self-adhesive figure obtained
3o is transparent. Nevertheless, if colorful figures are desired, it is
necessary to add a
pigment or mixture of pigments which are dispersible in various proportions in
accordance
to the desired color, preferably in a range of 0.02 to 5% by weight in respect
to the total
weight of the composition without including the pigment.
In a preferred embodiment of the present invention, the polymer
35 composition includes homopolymer resin of dispersion of polyvinyl chloride
in a range
between 40 and 50%, approximately, preferably from the types classified by the
American
PCT99l240
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Standard for Tests of Materials, in powdered materials, such as ASTM-0-S-34
and/or
ASTM D-1-34; a plasticizes of the family of phthalates as first plasticizes in
a range
between 50 and 55% by weight, approximately, preferably diodyl-phthalate
and/or
diisononyl-phthalate; soybean epoxy oil, as second plasticizes in
approximately 0.75% by
a weight; and an organo-metallic stabilizer, preferably barium, calcium and/or
zinc based in
approximately 0.75%.
In the embodiment that includes the exudation adjuvant agent, liquid
petrolatum is preferably used, also known as mineral oil or liquid Vaseline,
which is added
in a range from 8 to 12% by weight approximately.
m The pigments used are preferably of organic type.
It is important to point out that it is possible to add to the composition
other
adjuvant agents which are common within polymers industry, such as fillers
consisting of
talc or calcium carbonate, mould release agents, or other adjuvant agents.
Nevertheless,
these adjuvant agents do not allow the figure obtained to have an adequate
figure
i 5 adhesion, and consequently, the product obtained has a jeopardized
quality.
The polymer composition of the present invention is prepared in
accordance to the following procedure. The second plasticising agent and the
stabilizing
agent are introduced into a mixer that is set to work at low speed in
accordance to the
amount of composition to produce, in such a way that low shear stresses and a
good
2o distribution of the components are obtained at the same time. Once the two
compounds
have been adequately mixed, the polyvinyl chloride resin is incorporated
little by little to
the mixture formed with the second plasticising agent and the stabilizing
agent until they
are dispersed in the resin; in order to subsequently add gradually the first
plasticising
agent until it is dispersed in the polyvinyl chloride resin and a homogeneous
mixture of all
?5 the compounds is obtained.
If wanted, the mixture is subjected to vacuum conditions to eliminate air
bubbles trapped in the composition during the mixing procedure.
Once all the stages mentioned above are finished, the polymer composition
of the present invention is obtained, having paint appearance with a viscosity
from 50 to
60 centipoises, approximately, which is placed between the viscosities of
paint and thick
liquid or syrup. The polymer composition when rubbed between the fingers is
easily
spread, forming a layer of colorless oils. It is important to emphasize that
the viscosity is
variable, in accordance to the amount of each element of the composition that
is added,
as well as to the viscosity of the polyvinyl chloride resin used.
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In the embodiment of the composition that includes the exudation adjuvant
agent, the latter is added once the other components were perfectly mixed and
is stirred in
the mixer until it is fully incorporated into the mixture.
The mixture described in the last paragraph, can be subjected, if desired, to
a pigmentation procedure that consists of incorporate by means of a mixer the
pigment
previously dispersed in a plasticizer agent equivalent to the one used for the
base
composition and with the characteristics and properties adequate to obtain the
final color
that is necessary to obtain, whether translucent or opaque.
Once pigmented, the composition can be mixed with other compositions of
to the present invention with different pigment colors by means of shakers
and/or hand
mixers when a little amount of composition is processed to obtain compositions
with new
colors.
The polymer composition to elaborate self-adhesive figures can be processed by
means
of the traditional procedures for plastisoles, such as extrusion, injection,
compression,
~ 5 calender, casting and immersion.
For the manufacture of figures for signs systems from the polymer
composition for manufacturing self-adhesive figures of the present invention,
the
procedures of casting and immersion are preferably used.
In order to carry out the procedures of casting and immersion, it is
?u necessary to manufacture at least one mould having the shape of the figure
that is
intended to obtain, using a material resistant to moderated temperatures,
preferably
aluminum.
Once the mould is ready, it is filled with the polymer composition, wherein
polymerization of the composition is completed by means of a heating period
and at a
25 temperature enough to obtain an adequate consistency of the self-adhesive
figure. Once
the required consistency is reached, the figure obtained is released from its
mould.
The curing of the polymer composition is preferably performed by means of
heating at a temperature of 300°C for 4 minutes when it is manufactured
by means of the
procedures of casting or immersion.
3o When the procedure is performed by casting, the mould is filled with the
polymer composition in cold, for subsequently perform the curing of the
composition by
means of heat and finally cool the mould in cold water until it reaches room
temperature.
The figure obtained is released from the mould and drained to eliminate
humidity.
For the immersion procedure, the mould is filled with the polymer
,5 composition by means of the immersion of the mould in the same, by using a
device for
carrying moulds with capacity for carrying at least one mould, which is
subjected to a
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previous heating, for a time and temperature enough for the polymer
composition to
adhere to the mould. Immediately after the previous heating is over, the mould
is
submerged into the polymer composition for a period of time and at a speed
that depend
upon the thickness desired for the self-adhesive figure.
The ease of release of the polymer composition of the present invention
from the mould is due to the average contraction presented in the composition
when
casting, which is of approximately 0.5%, which allows the release without the
need of an
adjuvant agent for this purpose, independently of the molding procedure used.
From the polymer composition for manufacturing self-adhesive figures, it is
to possible to obtain self-adhesive figures that have the characteristic of
adhering to flat
surfaces without requiring a specific counterpart, for long time without
leaving stains when
they are removed. Additionally, it is possible to obtain translucent or
transparent figures,
depending upon the pigment which is used, that allow to observe through the
figure what
is written or drawn on the surface on which they are adhered, besides allowing
to draw or
l5 write on the figure itself if necessary. Nevertheless, it is also possible
to engrave, print or
stick any kind of graphic information on the front surface of the self-
adhesive figures
obtained from the composition of the present invention without affecting the
adherence
capacity of the same.
The self-adhesive figures obtained in accordance to the present invention,
?o have the physical and chemical properties inherent to polyvinyl chloride,
although they
also have the following characteristics: constantly exude their oily
components, which
causes the adherence to surfaces; they are flexible or semi-rigid; they swell
when
submerged in methyl chloride; they have high impact strength; absorb water in
approximately 0.53%; have an average tensile strength of approximately 127
kgf/cm2 (12
?5 454 4.45 Newtons per square meter); have an intermediate scratch
resistance; have an
average softening temperature of approximately 68°C; and, have
resistance to continuous
heat with a maximum temperature of approximately 70°C.
An infinity of self-adhesive figures can be obtained from the polymer
composition of polyvinyl chloride of the present invention whether by
manufacturing
3o moulds with the specific required shape or by swaging sheets manufactured
from such
polymer composition.
The sheets can be obtained by means of the traditional procedures for
plastisol processing as if they were any other figure, by means of the use of
suitable
moulds, with the characteristic that in order to achieve an optimal swage of
the sheets,
35 these are at least 0.5 mm wide, approximately, preferably between 1 and 2.5
mm wide.
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The dimensions of the sheet surface are established in accordance to the
figures that will be swaged on the same.
The swaging is made in cold or hot, by means of a press that has the
swage on its side of contact, which presses the sheet to make cuts on the
same. When
the swaging is made in cold, the press has a capacity of approximately 8 tons-
force
(78456 Newtons), while for the hot process, the swaging must be maintained at
a
temperature grater than approximately 50°C, with which the required
strength for the
press decreases to about 1 ton-force (9807 Newtons).
The following examples are destined to illustrate the scope of the present
to invention but do not restrict it.
EXAMPLES
METHODOLOGY
polymer compositions with different proportions of components were
prepared. Figures were obtained from the same by the casting procedure.
The figures obtained from the compositions were subjected to qualitative
tests, evaluating the properties of adequate flexibility and consistency for
handling the
2o figures, adherence of the fresh figure and adherence of the figure after a
daily use.
Flexibility and consistency were evaluated on the basis of the use of the
figures on white conventional blackboards.
Adherence of the figures was evaluated according to the following:
A glass sheet was placed horizontally and the figures were dropped from a
z5 height of 25 cm. Afterwards, the glass sheet was placed vertically to
verify whether there
was adherence or not. If the figure does not fall, the back of the glass sheet
is observed
in order to verify in a qualitative way, the amount of air bubbles trapped
between the figure
and the glass sheet. Subsequently, with the glass sheet still in vertical
position, one of the
comers of the obtained figures was lifted, in order to observe if the figure
adhered
3o completely again.
The adherence of the figures made with each polymer composition was
tested in freshly made figures and then on the same figures after one month of
continuous
normal use.
35 RESULTS
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The first composition was prepared by mixing 45.5% by weight of polyvinyl
chloride resin; 53% of dioctyl - phthalate; 0.75% of soybean epoxy oil; and,
0.75% of
barium-calcium-zinc organic stabilizer "MARK 380 B", thus obtaining after the
casting
procedure, figures with the characteristics of flexibility and consistency
adequate for its
use. The fresh figures were subjected to the test of adherence, staying
adhered when the
glass was lifted, with approximately 10% of the contact surface occupied by
air bubbles.
When lifting the corners of the fresh figures, they went back to adhere, but
the surface
occupied by air bubbles increased. After one month of continuous, normal use,
the test
was repeated and the surface occupied by air was approximately 25%.
to The second composition was prepared by mixing 65% of the polyvinyl
chloride resin; 33.5% of diodyl - phthalate; 0.75% of soybean epoxy oil; and,
0.75% of
barium-calcium-zinc organic stabilizer "MARK 380 B"_ obtaining after the
casting
procedure a figure too rigid and easily misshapen. About the adherence, the
figures did
not stay adhered when the glass was lifted, so the other tests were not
executed.
t5 The third composition was prepared by mixing 30% of the polyvinyl chloride
resin; 68.5% of dioctyl - phthalate; 0.75% of epoxy soy oil; and, 0.75% of
organic
stabilizer barium-calcium-zinc "MARK 380 B"_, thus obtaining after the casting
procedure
a figure too soft that loosed its body and shape easily, so it resulted to be
difficult to
handle, besides being very prone to trap dust, the latter fact, diminishing
its capacity of
zo adhesion. When the adherence tests were performed to the fresh figures, the
figures
stayed adhered when lifting the glass sheet, with approximately 5% of the
contact surface
occupied by air bubbles. When lifting the comers of the fresh figure adhered,
these
adhered again. Additionally, it was found that they left spots on the surface
of the glass,
although these were easily removable. After one month of continuous normal
use, the
z5 surface occupied by air was approximately 70%, so it was very difficult to
use it again.
The fourth composition was prepared by mixing 45.1 % of polyvinyl chloride
resin; 52.6% of dioctyl - phthalate; 2% of soybean epoxy oil; and, 0.3% of
barium-
calcium-zinc organic stabilizer "MARK 380 B"_, thus obtaining after the
casting procedure
a figure with stains and misshapen due to difficulties during the procedure of
formation of
3o the figure by casting, besides presenting some of the inconveniences of the
fourth
composition.
Finally, the fifth composition was prepared from the first composition, by
adding 10% weight of liquid petrolatum in respect to the first composition,
obtaining a
composition that allowed to obtain figures with better adherence
characteristics than the
35 figures obtained from the first composition, without jeopardizing the
characteristics of
flexibility and consistency. When the adherence tests were performed, it was
found that
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the fresh figures stayed adhered when the glass was lifted with approximately
5% of the
contact surface occupied by air bubbles. When lifting up the corners of the
adhered fresh
figure, these adhered again. After one month of normal, continuous use, the
surface
occupied by air was approximately 20%, so it was still easily adhesive.
As it can be observed from the above, the first polymer composition allows
the obtainment of self-adhesive figures with excellent properties of operation
and
adherence. On the other hand, the addition of liquid petrolatum as exudation
adjuvant to
the first composition allowed improving even more such properties.
Although certain specific embodiments of the present invention have been
lu illustrated and described above, it is to be understood that many
modifications thereof ace
possible. The present invention, therefore, is not to be restricted except
insofar as is
necessitated by the prior art and by the spirit of the enclosed claims.
