GB2349887A

GB2349887A - Polymer composition for making self adhesive figures

Info

Publication number: GB2349887A
Application number: GB0020510A
Authority: GB
Inventors: Genaro Aldrete-Frances
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-02-20
Filing date: 1999-02-19
Publication date: 2000-11-15
Also published as: CA2321790A1; GB0020510D0; AU2551399A; WO1999042982A1; BR9908334A

Abstract

The present invention relates to a polymer composition for the production of self-adhesive figures which have the characteristics of adhering to smooth surfaces during prolonged times without leaving stains when being removed, in addition to the fact that they can be reused; they have an extended useful life time and are easy to handle. The composition comprises basically a resin of polyvinyl chloride, a first plastifyer, a second plastifyer and a stabilizing agent which impedes the degradation of the polyvinyl chloride resin.

Description

1 "POLYMER COMPOSITION FOR MANUFACTURING SELF-ADHESIVE FIGUREW

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.

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 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 material of which the figure is made does not matter, as far as 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 the adhesion possible. It is important to emphasize 2 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 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 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.

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 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 or building directories, or like 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 3 characteristics required to 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 plastisoles, have been known and used for a long time. A typical composition of piastisol 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 for pencils, tool coatings, etc.

It is widely known that by means of the addition of an excess of plasticizer 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. Nevertheless, the piastisol 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 plasticizer, making is not so adequate to use.

Additionally, exudation of the plasticizer agent causes the surface on which the piastisol 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 of prior art methods for adhering 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 made does not leave stains when they are removed.

4 OBJECTIVES OF THE INVENTION Having in mind the defects of the prior art, it is an object of the present 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, 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 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 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 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. It has been found unexpectedly that it is possible to obtain the required adhesion properties in the figures for systems of signs only by means of the use of a composition including approximately from 35 to 60% by weight of polyvinyl chloride resine; 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 co-adjuvant agent is further added in a range. from 3 to 25% by weight, approximately, in respect to the total weight of the composition not including the co-adjuvant agent, the properties of which are 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 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 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 Standard for Tests of Materials, in powdered materials, such as ASTM-D-5-34 and/or ASTM D- 1 -34; a plasticizer of the family of phthalates as first plasticizer in a range between 50 and 55% by weight, approximately, preferably dioctyl-phthalate and/or diisononyl-phthalate; soybean epoxy oil, as second 6 plasticizer in approximately 0.75% by weight; and an organo-metallic stabilizer, preferably barium, calcium and/or zinc based in approximately 0.75%.

In the embodiment that includes the exudation co-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.

The pigments used are preferably of organic type.

It is important to point out that it is possible to add to the composition other co-adjuvant agents which are common within polymers industry, such as fillers consisting of talc or calcium carbonate, mould release agents, or other co adjuvant agents. Nevertheless, these co-adjuvant agents do not allow the figure obtained to have an adequate figure 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 platicising 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 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 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.

7 In the embodiment of the composition that includes the exudation co 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 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, 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 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 heating period and at a 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.

When the procedure is performed by casting, the mould is filled with the polymer composition in cold, for subsequently perform the curing of the 8 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 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 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 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 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, 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 9 of approximately 127 kgfIcm2 (12 454 445 Newtons per square meter); have an intermediate scratch resistance; have an average softening temperature of approximately WC; and, have resistance to continuous heat with a maximum temperature of approximately 700C.

An infinity of self-adhesive figures can be obtained from the polymer composition of polyvinyl' chloride of the present invention whether by manufacturing 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, these are at least 0.5 mm thick, approximately, preferably between 1 and 2.5 mm thick.

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 5WC, 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 invention but do not restrict it.

EXAMPLES

METHODOLOGY Five 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 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 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 thecomers of the obtained figures was lifted, in order to observe if the figure adhered 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.

RESULTS The first composition was prepared by mixing 4.5% 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 comers of the fresh figures, they adhered again, 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%.

The second composition was prepared by mixing 65% of the polyvinyl chloride resin; 33.5% of dioctyl 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 remain adhered when the glass was lifted, so the other tests were not executed.

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 lost 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 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 corners 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 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 W_, thus obtaining after the casting procedure a figure with stains and misshapen due to difficulties during the procedure of formation of 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 figures obtained from the first composition, without jeopardizing the characteristics of flexibility and consistency. When the adherence tests were performed, it was found that the fresh figures remained 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%, whereby 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 12 operation and adherence. On the other hand, the addition of liquid petrolatum as exudation co-adjuvant the first composition allowed improving even more such properties.

Although certain specific embodiments of the present invention have been illustrated and described above, it is to be understood that many modifications thereof are 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.

13 NOVELITY OF THE INVENTION

Claims

1.- A polymer composition for manufacturing self-adhesive figures of the type of plastisoies characterized by comprising: a polyvinyl chloride resin in a range from 35 to 60% by weight, approximately; a first plasticizer agent in a range from 37 to 64% by weight approximately; a second plasticizer agent in a range from 0.5 to 1.5% by weight, approximately; and, a stabilizing agent to avoid degradation of the polyvinyl chloride resin in a range from 0.5 to 1.5 by weight, approximately.

1- A polymer composition for manufacturing self-adhesive figures, according to claim 1, further characterized in that the polyvinyl chloride resin is added in a range from 40 to 50% weight.

1- A polymer composition for manufacturing self-adhesive figures according to claim 2, further characterized in that the polyvinyl chloride resin is a dispersion homopolymer of polyvinyl chloride.

4.- A polymer composition for manufacturing self-adhesive figures according to claim 3, further characterized in that the polyvinyl chloride resin is from the type classified by the American Standards for Tests of Materials for powdered materials such as ASTM D-5 --- 34 a nd/or ASTM D- 1 -34.

5.- A polymer composition. for manufacturing self-adhesive figures according to claim 1, further characterized in that the first plasticizing agent is a plasticizer from the family of the phthalates and is added in a range from 50 to 55% weight.

6.- A polymer composition for manufacturing self-adhesive figures according to claim 5, further characterized in that the first plasticizing agent is selected among dioctyl-phthalate andlor diisononyl - phthalate.

7-- A polymer composition for manufacturing self-adhesive figures according to claim 1, further characterized in that the second plasticizing agent is a soybean epoxy oil and is added in approximately 0.75% weight.

14 8.- A polymer composition for manufacturing self-adhesive figures according to claim 1, further characterized in that the stabilizing agent is organo metallic and is added in approximately 0.75% weight.

9.- A polymer composition for manufacturing self-adhesive figures according to claim 5, further characterized in that the stabilizing agent is barium, calcium andlor zinc based.

10, A polymer composition for manufacturing self-adhesive figures according to claim 1, further characterized in that the composition includes an exudation co-adjuvant agent.

11.- A polymer composition for manufacturing self-adhesive figures according to claim 10, further characterized in that the exudation coadjuvant agent is added in a range from 3 to 25% by weight, approximately, in respect to the total weight of the composition without including the co-adjuvant agent.

11- A polymer composition for manufacturing self-adhesive figures is according to claim 11, further characterized in that the exudation coadjuvant agent is liquid petrolatum and is added to the composition in a range from 8 to 12% weight.

11- A polymer composition for manufacturing self-adhesive figures according to claim 1 or 10, further characterized in that it includes a pigment or mixture of pigments dispersible in variable proportions in accordance to the color and transparency that is wanted to obtain.

14.- A polymer composition for manufacturing self-adhesive figures according to claim 13, further characterized in that the pigment has an organic origin and is added in a range from 0.02% to 5% by weight, approximately, in respect to the total weight of the composition without including the pigment.

15.- A polymer composition for manufacturing self-adhesive figures according to claim 14, further characterized in that the pigment is dispersed in the first plasticizing agent.

16.- A polymer composition for manufacturing self-adhesive figures according to claim 1, further characterized in that once the composition is subjected to a cuhng procedure, a figure is obtained having characteristics of adhering to flat surfaces for long times without leaving stains when they are removed, besides being able to be used again; having a long useful lifetime; and, being easily handled.

17.- A polymer composition for manufacturing self-adhesive figures according to claim 16, further characterized in that the composition suffers an average contraction after the curing of approximately 0.5%.

M- A polymer composition for manufacturing self-adhesive figures according to claim 16, further characterized in that the procedure of curing is selected among extrusion, injection, compression, calender, casting or immersion.

19.- A polymer composition for manufacturing self-adhesive figures according to claim 18, further characterized in that after the curing procedure, the figure obtained is subjected to a swaging procedure.

20.- A polymer composition for manufacturing a figure made out of the polymeric self-adhesive composition according to claim 19, further characterized in that the figure obtained is a sheet that is at least 0.5 mm thick approximately, preferably, between 1 and 2.5 mm.

21.- The use of the polymer composition, as claimed in claims 1 to 20, in the manufacture of self-adhesive figures which have characteristics of adhering to flat surfaces for long times, without leaving stains when they are removed, besides being suitable for being used again; having a long useful lifetime; and being handled easily.