ACTIVE AND INTELLIGENT ADDITIVE, POLYMER AND ARTICLE

Abstract

The present invention relates to active and intelligent additives having hybrid characteristics, that are compatible with polymers, are thermally and mechanically stable, are capable of releasing electrons and/or photons in the presence of chemical compounds, specifically amino compounds, amide compounds, oxygen reducing compounds, water or vapors thereof. The active and intelligent additives incorporate themselves into polymer matrices allowing the obtainment of active and intelligent polymeric articles. These active and intelligent polymeric articles may act as inhibitors of growth of microorganisms and fungi, as well as indicators of the presence of gasses, either in the atmosphere or caused by the decomposition of foodstuffs, for example.

Claims

1. An active and intelligent additive incorporated within a non-polar polymer matrix and formed of a sensitive compound encapsulated in an inorganic matrix with hybrid characteristics, said inorganic matrix with hybrid characteristics formed by a silicon alkoxide or a titanium alkoxide, wherein said sensitive compound releases electrons and/or photons as an antimicrobial agent in the presence of a reactive chemical compound by means of a reaction of corrosion of the encapsulated sensitive compound, said reactive chemical compound comprising any compound present in a medium that activates said sensitive compound, wherein said sensitive compound is selected from the group consisting of copper (I), sulfur, ascorbic acid and citric acid, and wherein said silicon alkoxide is selected from the group consisting of tetraethyl orthosilicate, ethyl triethoxysilane, methyl triethoxysilane, phenyl triethoxysilane, methyl trimethoxysilane, n-octyl ethoxysilane, n-butyl ethoxysilane and vinyl trimethoxysilane, and said titanium alkoxide is selected from the group consisting of tetraethoxy titanium, ethyltriethoxy titanium, methyltriethoxy titanium, phenyltriethoxy titanium, n-octylethoxy titanium and n-butylethoxy titanium, and wherein the polyolefin materials with the additive have antimicrobial activity.

2. The active and intelligent additive as recited in claim 1, wherein said reactive chemical compound is selected from the group consisting of amino compounds, amide compounds, oxygen-reducing compounds and/or vapors thereof.

3. The active and intelligent additive as recited in claim 1, wherein said non-polar polymer is a polyolefin.

4. The active and intelligent additive as recited in claim 3, wherein said polyolefin is a polyethylene.

5. The active and intelligent additive as recited in claim 3, wherein said polyolefin is a polypropylene.

6. An active and intelligent article, comprising the additive as recited in claim 1.

7. The active and intelligent additive as recited in claim 1, wherein said additive acts as an indicator of gas presence.

8. The active and intelligent additive as recited in claim 1, wherein said additive acts as a colorimetric indicator.

9. A non-polar polymer material comprising an active and intelligent additive incorporated within the non-polar polymer material, wherein said active and intelligent additive is formed of a sensitive compound encapsulated in an inorganic matrix with hybrid characteristics, said inorganic matrix with hybrid characteristics formed by a silicon alkoxide or a titanium alkoxide, wherein said sensitive compound releases electrons and/or photons as an antimicrobial agent in the presence of a reactive chemical compound by means of a reaction of corrosion of the encapsulated sensitive compound, said reactive chemical compound comprising any compound present in a medium that activates said sensitive compound, wherein said sensitive compound is selected from the group consisting of copper (I), sulfur, ascorbic acid and citric acid, and wherein said silicon alkoxide is selected from the group consisting of tetraethyl orthosilicate, ethyl triethoxysilane, methyl triethoxysilane, phenyl triethoxysilane, methyl trimethoxysilane, n-octyl ethoxysilane, n-butyl ethoxysilane and vinyl trimethoxysilane, and said titanium alkoxide is selected from the group consisting of tetraethoxy titanium, ethyltriethoxy titanium, methyltriethoxy titanium, phenyltriethoxy titanium, n-octylethoxy titanium and n-butylethoxy titanium, and wherein the materials with the additive have antimicrobial activity.

10. The non-polar polymer material as recited in claim 9, wherein said reactive chemical compound is selected from the group consisting of amino compounds, amide compounds, oxygen-reducing compounds and/or vapors thereof.

11. The non-polar polymer material as recited in claim 9, wherein said non-polar polymer is a polyolefin.

12. The non-polar polymer material as recited in claim 11, wherein said polyolefin is a polyethylene.

13. The non-polar polymer material as recited in claim 11, wherein said polyolefin is a polypropylene.

14. The non-polar polymer material as recited in claim 9, wherein said additive acts as an indicator of gas presence.

15. The non-polar polymer material as recited in claim 9, wherein said additive acts as a colorimetric indicator.

16. An active and intelligent article, comprising the non-polar polymer material as recited in claim 9.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0042] FIG. 1 is a Bode Graph obtained by EIS [Electrochemical Impedance Spectroscopy], commonly used to analyze the changes in electrical resistance of materials, wherein the electrochemical impedance module is compared against the sine wave frequency, and shows the change of electrical resistance of the polymeric film comprising the active and intelligent additive after exposure to the ammonia vapors.

[0043] FIG. 2 illustrates a graph that reflects the microbiological growth of Pseudomonas against shelf storage time in samples of chicken packaged with additive films using the active and intelligent additive.

EXAMPLES

[0044] The examples described herein relate to preferred embodiments of the present invention, and are thereby provided for purposes that are merely illustrative rather than limitative, so they should not be construed to constitute restrictions or to limit the scope of the present invention, whereby the latter should be interpreted in accordance with the scope of the claims attached herein.

[0045] The examples to follow are related to the obtainment of the active and intelligent additives, the activity thereof in identifying some analytes and the incorporation of such additives into polymer matrices.

Obtainment of the Active and Intelligent Additive

[0046] In general, in a preferred embodiment of the present invention, the active and intelligent additives are obtained by way of the following steps:

[0047] a) Preparation of a solution of the sensitive compound by dissolving a certain amount of this compound in a certain amount of solvent that constitutes the reaction medium itself. The amount of the sensitive compound vary from 0.005 grams to 1,000 grams dissolved within the range of from 1.0 mL to 100 L, at ambient temperature, whereby are obtained wide ranges of concentration.

[0048] b) Addition of the compounds obtained from the sol-gel reaction to item (a). Initially the pH value is conditioned by means of the addition of an acid or a base, as known in the art. Upon establishing the desired pH value, there are added the determined titanium or silicon alkoxides to generate the encapsulation of the electron-releasing compound (sensitive compound). The encapsulation by means of the addition of titanium or silicon alkoxides occurs by means of the control of the type of alkoxides, pH, temperature, time and the alkoxides/water ratio. With the determination of these variables there is controlled the relative percentage of organic and inorganic groups, that is, the degree of hybridism thereof.

[0049] c) Drying the suspension having been generated (if the active and intelligent additive was added in the form of powder).

[0050] The active and intelligent additive prepared in steps a, b and c, when dispersed in polymeric matrices, will evidence the releasing of electrons and/or photons upon interacting with amino, amide or oxygen reducing substances, either or not in the form of vapor. In addition it evidences a good dispersion ability and good compatibility as provided by the hybrid characteristic of the additive and by its thermal and mechanical stability.

[0051] The active and intelligent additive according to the present invention may be used as an antimicrobial agent, an indicator of the presence of an analyte, an indicator of communication (may be detected with the presence of a chip or another common electronic means), a generator of energy, an electrical conductor or electrical resistance reducer of a specific material, or for any other application that might require the presence of free electrons.

[0052] 1—Preparation of the Active and Intelligent Additive in the Form of Powder and Provision of Evidence of the Release of Electrons and of Color Change

[0053] The active and intelligent additive was obtained in accordance with the following methodology: 1.0 g of the sensitive compound (copper I chloride) was dispersed in a mixture of 5 mL of deionized H.sub.2O and 0.1 mL of concentrated HCl. Thereupon there were added thereto 4 mL of TEOS (tetraethyl orthosilicate) and 6 mL of OTMSi (octyl trimethoxysilane), or MTMSi (Methyl trimethoxysilane), or VTMSi (vinyl trimethoxysilane). The organosilanes reacted for 1 hour at ambient temperature and being subjected to mechanical stirring. Upon that time having elapsed, the solid product was ground until the particle size thereof reached the micron range and was washed with water until the washing residue became colorless, and was subsequently dried in an oven at 80° C. There was finally obtained an active and intelligent additive in the form of powder and having a greenish hue (Cu.sup.+).

[0054] For purposes of evidencing the active and intelligent action thereof, the additive obtained in Example 1 above was subjected to a basic gas (NH.sub.3) at ambient temperature. The solid obtained thereby acquired a bluish color (Cu.sup.2+) on reacting with ammonia, thereby evidencing the release of electrons by the copper oxidation reaction and the identification of amino compounds by the change in color, at ambient temperature.

[0055] The release of electrons took place by way of the following reaction:

Cu.sup.+.fwdarw.Cu′+e.sup.−

[0056] As previously set forth, the electron release may be used for the function of antimicrobial agent in an active package, and the color change may be used in an intelligent package for visual detection of an analyte. For example, foodstuffs undergoing a putrefaction process usually release amino compounds such as ammonia, due to the action of bacteria and fungi that transform the amino acids into gasses, and the electrons release in this case points out the presence of the ammonia by way of the change of color of the copper and further attacks the bacteria present therein, as previously explained, evidencing thereby an intelligent action (identification of the analyte by color change) and an active (antimicrobial) action.

[0057] 2—Incorporation of the Active and Intelligent Additive into the Polymeric Matrix and Evidencing the Release of Electrons and the Change in Color

[0058] The incorporation of the active and intelligent additive into the polymeric matrix was performed using standard extrusion procedures for polymer processing, such as temperature profile, type of thread and type of extruder normally used in an additivation process. Upon the incorporation of the active and intelligent additive into the polymer, there were fabricated films using a balloon-type film extruder, where the thickness of the films was between 10 and 100 μm.

[0059] The evidence of release of the electrons by the active and intelligent additive after incorporation of the same into the polymeric matrix was provided by the change in Electric (Ohmic) Resistance of the films. The electrical resistance property is characteristic for each type of material, as are the fusion heat, the density, etc. To such end, the films were exposed to ammonia vapors and were compared with the films that were not subjected to exposure to the ammonia vapors. The measurements of electrical resistance were made using the Electrochemical Impedance Spectroscopy (EIS) technique, which consists in the excitation of an electrochemical cell by a sine wave signal and the respective analysis of the current produced thereby. By means of the due mathematical treatment of that response, one is able to obtain the Impedance and the Ohmic Resistance of the material that is being subjected to measurements.

[0060] The graph of FIG. 1 represents the module of electrochemical impedance as a function of the frequency of the sine wave, wherein there may be observed the curve (a) which represents the impedance of the film with the additive incorporated therein, the curve (b) which represents the impedance of that same film, however in contact with NH.sub.3 gas, and the curve (c) which corresponds to the metallic copper (for purposes of comparison with conductive metals). There may be also noted an ample decrease of impedance of the film having the active and intelligent additive incorporated therein, in the presence of vapors of ammonia (NH.sub.3), when compared with the film with no presence of NH.sub.3. The polymeric film without the addition of the active and intelligent additive does not evidence any kind of change, since this is a property of the material and it is not affected by an external chemical action.

[0061] If compared with the curve (c) of the metal, we may note that, relatively to the presence of ammonia, the behavior of the film including the additive approximates the behavior of a metal, in what concerns the presence of electrons on the surface.

[0062] In Table 2 one may observe the decrease in electrical resistance of the described materials, once again confirming the release of electrons when in contact with the vapors of an analyte (ammonia). The former evidences the functioning of the active and intelligent additive when dispersed in a polymeric matrix, functioning as a releaser of electrons, which provides thereto suitability for all the applications that have been previously described herein. It may be noted that for the described films, the electrical resistance decreases in the order of 10.sup.3 to 10.sup.4 Ohms when in the presence of NH.sub.3 gas. This is caused by the release of electrons from each of the different films having been fabricated.

[0063] When compared with the pure film devoid of additive, one may observe that the decrease of electrical resistance of the film with the active and intelligent additive incorporated therein, in the presence of ammonia, is about 100 to 1000 times. The former shows that the active and intelligent additive has the ability to change the electrical resistance characteristics of the materials, providing a wide range of new applications. The former could present distinct applications such as a switch, which in the presence of a certain analyte allows the communication of specific environment conditions, either by way of the release of electrons or by changing color.

TABLE-US-00002 TABLE 2 Decrease of the electrical resistance of the films by the release of electrons. Electrical Electrical resistance in the Film resistance presence of NH.sub.3 vapor Pure film without 6.7 × 10.sup.10 Ω 1.5 × 10.sup.9 Ω additive Film with additive 7.0 × 10.sup.9 Ω 1.1 × 10.sup.5 Ω based on citric acid Film with additive 1.6 × 10.sup.9 Ω 3.0 × 10.sup.5 Ω based on sulfur Film with additive 6.2 × 10.sup.9 Ω 2.2 × 10.sup.6 Ω based on copper (I)

[0064] This demonstrates the presence of free electrons in the polymeric film when arising from the contact of the active and intelligent additive with an analyte (ammonia vapor).

[0065] 3—Evidence of the Antimicrobial Action of the Films Whereto was Added the Active and Intelligent Additive.

[0066] The methodology used to determine the antimicrobial effect was practiced by means of the total bacteriological count of microorganisms, specifically Pseudomonas, varying the shelf storage time of the foodstuff.

[0067] Method: Pieces of chicken breast of approximately 50 grams each were packaged with the films provided with the active and intelligent additive. These films, containing the chicken breasts, were sealed in the form of bags, thereby simulating the shelf storage conditions of the packaged foodstuff. Subsequently the said bags containing the chicken breasts were packaged in a secondary bag of polyolefin film (without the incorporation of the active and intelligent additives) using vacuum (the same test may be conducted using a film co-extruded with an additive-bearing layer and a layer with no additive). The innermost layer, which contains the additive, is intended for the purpose of perceiving the electrons released by the volatile compounds produced by the degradation of the foodstuff and to promote the migration thereof to the surface of the film which is in direct contact with the foodstuff (innermost surface) rather than to the outer part, in which, in this specific case, it would not evidence any advantage, being devoid of antimicrobial efficiency (which would occur by means of the loss of the electrons to the external surface). Subsequently to the packaging, there were conducted the analyses of counting of Pseudomonas once every three days to determine the microbiological growth as a function of time and to observe the antimicrobial action of the polymeric films additivated with the active and intelligent additives.

[0068] In the graph of FIG. 2, the samples used for the study were the following:

[0069] LHB: Polyolefin film (without incorporating the active and intelligent additive).

[0070] CuV-10/E3: LHB with the incorporation of the Copper-based active and intelligent additive and a hybrid ratio TEOS/VTMSi (vinylic)

[0071] CuC8-10/E5: LHB with the incorporation of the Copper-based active and intelligent additive and a hybrid ratio TEOS/OTMSi (octyl)

[0072] CuC1-20/E4: LHB with the incorporation of the Copper-based active and intelligent additive and a hybrid ratio TEOS/MTMSi (methyl)

[0073] ACV-10/E2: LHB with the incorporation of the Citric Acid-based active and intelligent additive and a hybrid ratio TEOS/VTMSi (vinylic)

[0074] There may be noted an exponential growth of the Pseudomonas that was equal for all samples up until the seventh day, when there was reached a concentration of 1×10.sup.6 UFC. After 7 days, the samples of CuC8-10/E5, CuC1-20/E4 and ACV-10/E2 evidenced a reduction in the growth of the Pseudomonas. The sample CuC8-10/E5 evidenced the best behavior in reducing the growth of Pseudomonas, and specifically with this sample there was once again achieved the value of 1×10.sup.6 UFC on the 11.sup.th day. These results clearly show the microbiological growth inhibiting effect in the samples of film comprising the active and intelligent additives. Specifically, the sample that evidenced a greater level of efficiency in reducing the microbiological growth was the sample identified as CuC8-10/E5. This constitutes extremely strong proof of the effect as inhibitor of microbiological growth of Pseudomonas in samples of chicken breast, when the latter were packaged using the films that were additivated using the active and intelligent additives according to the present invention. Thus, there may be established an increase of 4 days in the useful time of the said foodstuff and there has been demonstrated the use of the packages made with these films provided with the additives according to the present invention as constituting active and intelligent packages.

[0075] The reduction of growth of Pseudomonas was due to the release of the electrons contained in the active and intelligent additives, which when placed in contact with the gasses produced by the decomposition of the chicken, evidence the release of electrons, whereby the cited electrons interact with the Pseudomonas, inhibiting the growth of the latter.

[0076] All documents cited in the present document are incorporated hereto for purposes of reference, as regards the relevant part thereof. The citation of any document should not be construed as an admission of the fact that the same might represent prior art with relation to the present invention. Although there were illustrated in the examples and drawings attached hereto, and described in the instant specification, some preferred embodiments of the invention, it should be obvious to a technician skilled in the art that the invention is in no way limited to the realizations thereof as described herein, and there should be rather construed that other alterations, modifications and substitutions may be made without deviating from the characteristic nature and scope of the invention, which is defined in the claims attached hereto.