Dye-exchange zeolite marker

Abstract

A dye-exchanged zeolite marker, wherein the zeolite is characterized by a pore size comprised between 4 Å and 12 Å and the dye is an organic cationic molecule characterized by an amount of the dye comprised between 0.05% by weight and 1% by weight relative to the weight of the zeolite; an optically active composition comprising the dye-exchanged zeolite marker dispersed in a polymer matrix; and their use as detectable markers.

Description

[Technical Field]

[0001] The present invention relates to dye-exchanged zeolite markers and optically active compositions comprising said markers dispersed in a polymer matrix. [Background technology]

[0002] Numerous patent publications, such as EP 1409997, EP 1356478, WO 2011 / 045572, WO 2021 / 113377, or U.S. 2010 / 0003762, relate to a wide range of possible applications, such as the preparation of marking materials for anti-counterfeiting purposes, inventory control or warranty purposes, detecting the presence of specific substances in specific media, or as packaging solutions. A well-known means of detecting specific substances is represented by the use of colorimetric indicators that rely on the optical properties of reactive dyes or inks under specific conditions. In particular, these dyes can exist in at least two different chemical states, with each form of the dye absorbing light in a specific range of wavelengths. When such a reactive dye, present in a first form, is exposed to a given substance, it reacts with the substance via a reversible chemical reaction, thereby changing into the second form of the dye. Because the second form of the dye absorbs a different wavelength of light, the chemical reaction results in a visible, and thus detectable, color change.

[0003] Incorporation of the molecules into the desired substrate, which also potentially involves the use of zeolites, is typically achieved by the impregnation method disclosed in WO 2011 / 045572 or the post-treatment method reported in U.S. Pat. No. 11,027,241. Also, Chinese Patent Application Publication No. 110903826 disclosed the use of fluorescent molecules such as rhodamine incorporated into the surface of metal-organic framework (MOF)-type structures using a diffusion impregnation technique. Meanwhile, WO 2021 / 113377 describes antibacterial zeolite nanoparticles that, in addition to metal species, may further comprise an optical tracer (e.g., a fluorophore) non-covalently or covalently bound to the surface of the zeolite but not within the pores of the nanoparticles.

[0004] The main drawback of such an approach relates to the limited stability of the final system, which tends to easily release dye molecules that are decomposed under extrusion processes in the case of thermoplastic matrices or when exposed to heat treatments in the presence of water or other solvents.

[0005] A further potential approach reported in WO 2005 / 052069 is based on the use of pigments, the pigment compositions being realized by substitution reaction with one or more cationic dye groups in the presence of a suspension of zeolite pigments. However, one of the negative consequences of the use of both organic and inorganic pigments disclosed in WO 2005 / 052069 relates to the large amount of dye relative to the amount of zeolite required to obtain the desired coloration, and the resulting high dye / zeolite ratio. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent Application Publication No. 1409997 [Patent Document 2] European Patent Application Publication No. 1356478 [Patent Document 3] International Publication No. 2011 / 045572 [Patent Document 4] International Publication No. 2021 / 113377 [Patent Document 5] US Patent Application Publication No. 2010 / 0003762 [Patent Document 6] U.S. Patent No. 1,102,7241 [Patent Document 7] Chinese Patent Application Publication No. 110903826 [Patent Document 8] International Publication No. 2005 / 052069 [Non-patent literature]

[0007] [Non-Patent Document 1] T. Nedelcev et al. / Dyes and Pigments 76 (2008) 550e556 Summary of the Invention [Problem to be solved by the invention]

[0008] Thus, there remains a need to develop new chemical indicators, particularly markers, that provide simple, reliable, and cost-effective means of detection that exhibit improved stability relative to those known in the art, particularly when threatened by heat or in contact with solvents. There is also a need to develop new optically active compositions incorporating such markers that can be prepared and processed via known polymer processing techniques while maintaining the efficacy and stability of the new indicators. [Means for solving the problem]

[0009] The present invention overcomes the aforementioned shortcomings of the prior art by providing dye-exchanged zeolite markers prepared by a cation exchange reaction between the cations of the zeolite and one of the dye organic molecules.

[0010] In the context of the present disclosure, the term "dye-exchanged zeolite marker" should be taken to mean a marker or indicator, as is generally known in the art, that is based in particular on zeolite and that can be obtained by a cation exchange reaction between a cationic dye and a zeolite. The shortened form "marker" is used interchangeably with "dye-exchanged zeolite marker."

[0011] More particularly, with the aim of providing a marker species that can overcome the prior art problems of low stability disclosed above, the inventors of the present invention have surprisingly found that when a cation exchange reaction occurs between the dye and the zeolite, the dye is more efficiently bound to the zeolite, in particular to the pores of the zeolite, and as a result is not released or decomposed when in contact with solvents or high temperature conditions, i.e. is more stable with respect to those known in the art.

[0012] Accordingly, the present invention relates to a dye-exchanged zeolite marker comprising a zeolite and a dye organic molecule, the marker being obtainable via a cation exchange reaction between at least one cation of the zeolite and at least one cation of the dye organic molecule.

[0013] Furthermore, it has been found that by using a reduced amount of dye molecules relative to the zeolite, the detectable properties of the obtained marker can still be measured without changing the surface characteristics of the zeolite and its applicability for different applications. Therefore, the present invention also relates to a dye-exchanged zeolite marker comprising a zeolite and a dye organic molecule, advantageously in which the mass ratio between the dye and the zeolite is comprised between 0.05% and 1% by mass, preferably between 0.1% and 0.5% by mass, relative to the mass of the zeolite. In other words, in contrast to those disclosed in the prior art, the marker of the present invention does not require a high dye / zeolite ratio to obtain the desired coloration.

[0014] As will be apparent from the experimental section of this disclosure, measurement of zeolite pore size can play an important role in the preparation of the dye-exchanged zeolite markers of the present invention, at least in terms of process yield. Dye-exchanged zeolites with pore sizes comprised between 4 Å and 12 Å have been found to be particularly beneficial.

[0015] The present invention also relates to an optically active composition comprising a dye-exchanged zeolite marker as disclosed herein and a polymer matrix, preferably wherein the marker is dispersed within the polymer matrix.

[0016] Additionally, the present invention relates to the use of the dye-exchanged zeolites or compositions disclosed herein as detectable markers, and to detectable articles that comprise, incorporate, or are coated (at least in part) with a dye-exchanged zeolite or composition according to the present invention. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a graph showing thermogravimetric analysis combined with mass spectrometry (TG-MS) to evaluate organic vapor evolution during the process simulation for samples C2 and S2. During the ramp at 250° C., some organic evolution was clearly identified for sample C2 due to the onset of decomposition, while for sample S2, there was no organic evolution (always at zero level), confirming that the decomposition process was not triggered in this sample due to the stability of the dye-zeolite bond. DETAILED DESCRIPTION OF THE INVENTION

[0018] As anticipated above, the present inventors have, after extensive investigation, found that dye-exchanged zeolite markers obtained via a cation exchange reaction between zeolite and a dye are more stable than other zeolite-based markers already known in the art in which the dye is simply adsorbed onto the zeolite.

[0019] Accordingly, the present invention relates to a dye-exchanged zeolite marker comprising a zeolite and an organic cationic dye, the marker being obtainable via a cation exchange reaction between at least one cation of the zeolite and at least one cation of the organic cationic dye.

[0020] As is evident from the experimental section of this disclosure, the inventors have found particularly advantageous zeolites with pore sizes comprised between 4 Å and 12 Å, which allow for more efficient dye binding to the zeolite and better process yields. Surface area and porosity analyses were performed using a Micromeritics BET instrument. Prior to analysis, samples were preconditioned by degassing in a turbovacuum at 180°C, which allowed for the removal of physically bound impurities from the analyzed material. The analysis was then continued using CO2 (at -20°C) for LTA or Ar (at -186°C) for the other zeolites. Micropore surface areas were calculated using the Dubinin-Astakhov model, while pore sizes were calculated using the Saito-Foley or NLDFT models.

[0021] Another important feature of the markers obtainable according to the invention is that they allow effective detection despite rather low dye / zeolite mass ratios (samples S1 to S4, see Table 1). Surprisingly, even with a mass ratio between dye and zeolite of 0.05% to 1% by mass, preferably 0.1% to 0.5% by mass (inclusive) relative to the mass of the zeolite, the markers allow effective detection without modifying the surface characteristics of the zeolite.

[0022] Accordingly, the present invention provides a dye-exchanged zeolite marker comprising a zeolite and a dye, - the zeolite is characterized by a pore size comprised between 4 Å and 12 Å, - the dye is an organic cationic molecule, - the amount of dye is 0.05% by mass to 1% by mass relative to the mass of the zeolite; Dye-exchanged zeolite markers.

[0023] Zeolites suitable for the purposes of the present invention are those generally known in the art, provided that they have a pore size comprised between 4 Å and 12 Å. Preferably, the zeolite is a faujasite type zeolite (FAU) or a mordenite zeolite (MOR).

[0024] The dye is a colorimetric dye commonly known in the art, preferably an organic cationic dye. Preferably, the dye is rhodamine or a derivative thereof, more preferably, the dye is selected from the group consisting of rhodamine B, tetramethylrhodamine isothiocyanate-dextran, rhodamine 6G, rhodamine B isothiocyanate, rhodamine 19 percolate, and other rhodamine derivatives.

[0025] According to an optional embodiment of the present invention, the aforementioned zeolite has a particle size of X comprised between 0.5 and 50 μm, preferably between 0.5 and 20 μm. 90 is in the form of a powder having an average particle size characterized by a value of X 90 indicates the spherical diameter within which 90% of the particles in a sample fall on a volume basis.

[0026] Since the dyes bind efficiently to the interior part of the zeolite, one of the further advantages of said markers relates to the possibility to use the zeolite surface for further functionalization and activation.

[0027] Indeed, in a preferred embodiment of the present invention, the zeolite surface of the marker is modified with alkoxysilanes, such as (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride, octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, tetradecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, n,n-didecyl-N-methyl-N-(3-trimethoxysilylpropyl)ammonium chloride, s-(trimethoxysilylpropyl)isothiouronium chloride, 3-(trihydroxysilyl)propyldimethyloctadecylammonium chloride, silsesquioxane 3-(dimethyloctadecylammonio)propyl, hydroxy-terminated chloride, and (3-glycidoxypropyl)trimethoxysilane. The modification is carried out with the alkoxysilanes by hydrolysis and condensation. Preferably, the alkoxysilane derivative or alkoxysilane moiety is present in an amount comprised between 1 and 40% by weight relative to the zeolite weight. The silane moiety can then be utilized for its intrinsic properties or as a linker for further reaction or polymerization steps.

[0028] Dye-exchanged zeolite markers according to any of the embodiments disclosed herein can also be dispersed in a polymer matrix to obtain an optically active composition.

[0029] Accordingly, the present invention also relates to compositions comprising a dye-exchanged zeolite marker according to any of the embodiments disclosed herein and a polymer or polymer matrix. The polymer matrix should be characterized by the absence of excitation and emission features (peaks and / or more complex spectral features such that absorption and / or emission generally increase) at levels that may perturb the excitation or emission of the marker. Specifically, since the excitation and emission peaks of rhodamine or rhodamine-derivative dyes are centered at 560 nm and 580 nm, respectively, a suitable polymer matrix is characterized by the absence of excitation and emission features in the range of 460 to 680 nm, taking into account the buffer spectral range specified by ±100 nm.

[0030] In a preferred embodiment, the polymer matrix is polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS) and their copolymers and functionalized polymers, acrylics, acrylic-styrene, vinyl and alkyl copolymers, urethane-acrylic, aliphatic-urethane, urethane, polyurethane, epoxy, siloxane and polysiloxane, phenolic resins, poly[ethene-co-(vinyl alcohol)] (EVOH), poly(vinyl alcohol) (PVAL), poly(lactic-co-glycolic acid) (PLGA), polyethylene glycol (PEG), poly(vinyl acetate) (PVAC), aqueous or water-reducible latex, polylactic acid (PLA), aliphatic / aromatic co-polyesters, Polyesters, preferably polybutylene adipate terephthalate (PBAT) and poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene succinate-co-butylene terephthalate) (PBST), aliphatic co-polyesters derived from 1,4 butanediol and carboxylic acids, preferably poly(butylene succinate) (PBS) and polybutylene succinate adipate (PBSA), polyhydroxyalkanoates (PHAs), preferably polyhydroxybutyrate (PHB), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), polyhydroxybutyrate-hexanoate (PHBH), natural polymers, in particular polysaccharide polymers, such as chitosan, sodium alginate and starch or modified starch, and mixtures thereof. Preferred examples of polymer blends are blends of polylactic acid (PLA) and polyhydroxybutyrate / polyhydroxyvalerate (PHBV), or blends of polyvinyl alcohol (PVOH) and hydroxypropylated starch ether (STARCH).

[0031] In the resulting active composition, the dye-exchanged zeolite marker is preferably present in an amount comprised between 0.1 and 10% by weight relative to the weight of the polymer matrix.

[0032] In a further embodiment, one or more further components, such as fillers, are added to the composition, preferably in an amount comprised between 0.1 and 20% by weight with respect to the polymer matrix, and may be selected from the group consisting of hydrotalcite, zirconium phosphate, porphyrins, graphene and other two-dimensional crystals, zeolites, halloysite, graphene oxide, metal-organic frameworks (MOFs), organic beads, cellulose and antioxidant capsules, self-assembling proteins, ester-terminated polyamides, tertiary amide-terminated polyamides, polyether polyamides, polyalkyleneoxy-terminated polyamides, and mixtures thereof.

[0033] As will be apparent from the following non-limiting examples, the dye-exchanged zeolites of the present invention, and polymer compositions containing them, have been shown to possess effective optical activity.

[0034] Therefore, the present invention also relates to the use of said dye-exchanged zeolites or polymer compositions containing them as detectable markers.

[0035] As will be apparent to those skilled in the art, the dye-exchanged zeolite or polymer compositions of the present invention can be incorporated into or coated onto items, such as packaging, fabrics, general plastic items, etc., to render the item, or at least a portion thereof, detectable by the dye-exchanged zeolite or polymer composition of the present invention.

[0036] Thus, the present invention also relates to an item or article, preferably selected from packaging, fabric, garments, devices, such as medical devices, optical tags, marking components, anti-counterfeiting elements, at least in part comprising, incorporating, or coated with a dye-exchanged zeolite or polymer composition according to any one of the embodiments disclosed herein.

[0037] In light of the above, the dye-exchanged zeolites according to any embodiment of the present invention can be processed into the form of coatings, films, lacquers, frames, three-dimensional elements, pellets or sheets, or generally any other form suitable for the intended purpose.

[0038] The markers can be used as is to obtain an optically active composition or can be included in a polymer matrix as disclosed above.

[0039] Several methods can be used to prepare polymer / zeolite composites, such as in situ polymerization, polymer melting and mixing, extrusion, melt blending, or other molding processes (e.g., injection, transfer, compression, foaming, thermoforming, film blowing).

[0040] As will be apparent from the experimental section below, the present invention also relates to methods for the preparation of polymer compositions comprising dye-exchanged zeolite markers according to any of the embodiments disclosed herein via in situ polymerization, polymer dissolution and mixing, or melt blending, and compositions obtainable thereby. [Example]

[0041] Experimental section The present invention will now be described in more detail with reference to the following non-limiting examples. Modifications or variations of the embodiments exemplified herein that are obvious to those skilled in the art are intended to be encompassed within the scope of the appended claims.

[0042] Preparation of rhodamine-exchanged zeolite markers (samples S1-S6 and corresponding example C1) Rhodamine B (RhB) or RhB-dextran (both from Sigma-Aldrich) in an amount ranging from 0.05 to 1.25 g was dissolved in 100 mL of distilled water. 5 g of zeolite was then added to the mixture, and the pH of the mixture was adjusted to 6 using HCl (1 M) solution. Protected from light, the mixture was stirred at room temperature for 24 h using a laboratory magnetic stirrer. The resulting complex was then purified via filtration. Purification involved thoroughly washing the powder with distilled water until the collected filtrate was completely clear. The resulting rhodamine-exchanged complex was dried overnight in an oven at 80 °C.

[0043] [Table 1]

[0044] After the ion exchange reaction with 0.25 g of RhB and LTA zeolite (C1), the content of Rhodamine B in the LTA zeolite became very low (0.02% by mass), making this sample unsuitable for use as a marker.

[0045] Preparation of Example C2 A quantity of 0.25 g of Rhodamine B (RhB) was mechanically mixed with 5 g of zeolite to ensure efficient dispersion of the various materials in powder form, and the resulting mixture was dried in an oven at 80° C. overnight.

[0046] Preparation of Example C3 A quantity of 0.25 g of 9-(diethylamino)-5H-benzo[a]phenoxazin-5-one (surrogate marker NR) was dissolved in 100 mL of dimethyl sulfoxide. 5 g of zeolite was then added to the mixture. Protected from light, the mixture was stirred at room temperature for 24 hours using a laboratory magnetic stirrer. The resulting complex was then purified via filtration. Purification involved thoroughly washing the powder with distilled water until the collected filtrate was completely clear. The resulting exchanged complex was dried overnight in an oven at 80 °C.

[0047] Preparation of Example C4 A quantity of 0.25 g of fluorescein 5(6)-isothiocyanate (a surrogate marker, FITC) was dissolved in 100 mL of distilled water. 5 g of zeolite was then added to the mixture. Protected from light, the mixture was stirred at room temperature for 24 hours using a laboratory magnetic stirrer. The resulting complex was then purified via filtration. Purification involved thoroughly washing the powder with distilled water until the collected filtrate was completely clear. The resulting exchanged complex was dried overnight in an oven at 80 °C.

[0048] Preparation of Example C5 (3-Aminopropyl)triethoxysilane-rhodamine (APTES-RhB) molecules were prepared prior to their attachment to the zeolite surface. The synthesis followed the protocol described by T. Nedelcev et al., Dyes and Pigments 76 (2008) 550e556. Briefly, rhodamine B (0.002 mol, 0.96 g) was dissolved in chloroform (30 ml). The solution was stirred and heated to the boiling point of chloroform (61.2 °C). APTES (ABCR) (0.002 mol, 0.465 ml) was then added dropwise to the rhodamine B solution under stirring. The reaction was stopped after 30 min, and the chloroform was then removed from the reaction mixture using a rotary evaporator. The remaining material (silanized rhodamine, approximately 1.3 g) was dried in an oven at 60 °C.

[0049] Emission tests for samples S1 to S6 and corresponding examples C1 to C4 In dye-exchanged zeolite markers, marker dispersions can be directly examined to verify that the dye is efficiently bound to the zeolite and, as a result, is not released upon contact with the solvent or upon exposure to elevated temperatures. A 22.4 mg quantity of selected samples (S1–S6) or corresponding examples (C1–C4) was dispersed in 20 g of solvent. The samples were vigorously stirred at room temperature (RT) and then allowed to stand for 24 h. The supernatant was analyzed for appearance via simple naked-eye observation and compared with a reference colored sample (R1) obtained by dissolving 1.12 mg (2.34E-06 mol) of RhB powder in 20 g of solvent, as follows: The list of applied solvents included distilled water, acetone, dimethyl sulfoxide, tetrahydrofuran, chloroform, and dichloromethane (DCM). For all applied solvents, completely transparent dispersions confirmed the absence of dye release, as reported in Table 2.

[0050] As a further test, dispersions of the prepared samples were heated to 50°C and vigorously stirred for 10 minutes, then allowed to stand for 24 hours. Again, the sample supernatants were analyzed for appearance via simple naked eye observation and compared to a reference colored dye sample, as follows. Completely transparent dispersions confirmed the absence of dye release and the absence of a spectrophotometric signal attributable to the dye, confirming its absence. The stability results observed for the room temperature samples were confirmed after heat treatment, as reported in Table 2.

[0051] The dispersions prepared as reported above were further analyzed by UV-Vis spectrophotometer. A calibration curve was defined for each solvent, and the detection limit (DL) of 1 ppm was determined. The influence of some parameters, such as solvent characteristics, temperature, and stirring time, was examined. The results are reported in Table 3. No absorption peaks were detected, and the detection limit was determined for each solvent, with a calculated relative error of 15%.

[0052] [Table 2]

[0053] [Table 3]

[0054] To confirm the increased stability of the markers prepared according to the present invention, samples C2 and S2 were further exposed to a heating treatment simulating polymer processing, characterized by a steep ramp (50°C / min) to 250°C and a 5-minute isotherm in a thermogravimetric mass spectrometry (TG-MS) instrument, to identify traces of organic moieties derived from Rhodamine B decomposition. As reported in Graph 1, when sample C2 was subjected to the above treatment, some organic moieties were clearly identified, while for sample S2, the organic moieties always remained at zero level.

[0055] Contact Angle Test Contact angle measurement is a technique used to determine the wetting characteristics of a liquid droplet on a solid surface. The contact angle is the angle formed between the tangent to the three-phase contact line of the droplet and the solid surface.

[0056] First, the solid substrate of interest was prepared to measure wetting behavior. In this case, the substrate was a zeolite powder pill. Then, a small droplet of the liquid under investigation was carefully placed on the solid surface using a syringe, micropipette, or other precise dispensing method.

[0057] Finally, a high-resolution camera was used to capture images of the droplets on the solid surface from a suitable angle. Compared to standard protocols, imaging of zeolite pills requires extremely rapid imaging, taking less than 1 second. The resulting images were then processed using specific software to analyze the droplet shape and determine the contact angle.

[0058] When water is used as the liquid probe, if the contact angle is <90° the sample is labeled as hydrophilic (polar surface, strong interaction with HO), whereas if the result is >90° it is labeled as hydrophobic.

[0059] While normal zeolite surfaces are hydrophilic, when the powder surface is functionalized with organic molecules, the zeolite surface can become hydrophobic.

[0060] Contact angle analysis was performed on sample S2 and corresponding example C5. The relative results reported in Table 4 reveal that only by the procedure of the present invention it is possible to have rhodamine in the pores of the zeolite, whereas by following procedures known in the art, rhodamine is bound to the exterior surface.

[0061] As a result, the zeolites disclosed herein containing rhodamine inside the pores are easier to incorporate into further matrices / compositions in contrast to hydrophobic zeolites such as C5, and in addition, the zeolites are characterized by the possibility of having further interactions or functionalization on the surface.

[0062] [Table 4]

[0063] Preparation method for dispersing dye-exchanged zeolite markers in a polymer matrix to obtain optically active compositions Several methods can be used to prepare the polymer / zeolite composite, such as in situ polymerization, polymer melting and mixing, or melt blending.

[0064] Preparation by in-situ polymerization is based on the first step of blending polymer precursors and then derivatizing the dye using an efficient technique to obtain a fine dispersion. After obtaining a homogeneous dispersion, the liquid formulation is applied to a support and the polymerization process is accelerated by initiator activation. Different activation regimes can be applied according to the characteristics of the initiator and the chemical composition of the formulation. Typical techniques are based on heat treatment or UV irradiation.

[0065] The solution mixing method involves four steps: solubilization of the polymer matrix in a suitable solvent at room temperature or elevated temperature, dispersion of the zeolite in the solvent, mixing of the two solutions by mechanical stirring or tip / bath sonication, and finally, precipitating or casting the mixture to obtain a film after evaporation of the solvent.

[0066] Melt blending is a commonly used technique for making thermoplastic / zeolite composites. Melt blending uses high temperatures and high shear forces applied in industrial processes to disperse the zeolite. Depending on the desired final morphology / shape of the composite, the bulk material can be processed by various post-extrusion techniques, such as film forming, injection molding, compression molding, and melt spinning.

[0067] Below various examples are reported according to the various preparation methods according to the invention:

[0068] [Table 5]

[0069] Sample AC 1. A film of the active composition was prepared by mixing 1.5 grams of polyethylene glycol dimethacrylate (PEGDMA) with 0.07 grams of ESACURE ONE (a bifunctional oligomeric alpha hydroxyketone) from IGM resins as a free radical-generating photoinitiator. After the photoinitiator was completely dissolved, 0.015 g of rhodamine-zeolite sample S2 was added to the formulation at room temperature and mechanically mixed for 30 minutes. The resulting formulation was spread onto a glass substrate at a thickness of 50 microns using a doctor blade, and the UV lamp was turned on at 100 mW / cm. 2 at an illumination intensity of 365 nm for 15 seconds at a focus of 1.5 J / cm 2 The polymerization process was carried out in a glove box environment under inert gas flux. A reference PEGDMA (UV-cured) film without markers was also prepared by applying the same experimental protocol.

[0070] Sample AC 2. A film of the active composition was prepared by mixing 1.5 grams of polyethylene glycol dimethacrylate with 0.07 grams of azobisisobutyronitrile (AIBN) from Sigma Aldrich as a free-radical-generating thermal initiator. After the initiator was completely dissolved, 0.015 g of rhodamine-zeolite sample S2 was added to the formulation at room temperature, and mechanical mixing was carried out for 30 minutes. The resulting formulation was spread onto a glass substrate at a thickness of 50 microns using a doctor blade, and the sample was heated at 80°C for 30 minutes to promote the polymerization process. The polymerization process was carried out in a glovebox environment under inert gas flux.

[0071] A reference PEGDMA (thermoset) film without marker was also prepared applying the same experimental protocol.

[0072] Sample AC 3. A film of the active composition was prepared by mixing 0.9 grams of Epikote™ 862 (bisphenol F resin) manufactured by Hexion with 0.15 grams of Epon 8111 (epoxy acrylate resin) manufactured by Hexion and 0.38 grams of Epikote™ 03161 (rubber-modified bisphenol A resin) manufactured by Hexion. The resulting mixture was vigorously stirred by mechanical mixing for 1 hour to obtain a homogeneous solution. 0.08 grams of triarylsulfonium hexafluoroantimonate salt as a cationic initiator was then added and dissolved by mechanical mixing for 30 minutes. After the initiator was completely dissolved, 0.015 g of rhodamine-zeolite sample S2 was added to the mixture at room temperature, and mechanical mixing was continued for an additional 30 minutes. The resulting mixture was spread onto a glass substrate at a thickness of 50 microns using a doctor blade and treated with UV at 100 mW / cm. 2 Illumination at λ=365 nm was applied for 120 s to facilitate the polymerization process.

[0073] A marker-free diglycidyl ether of bisphenol F (DGEBF)-based reference film was also prepared applying the same experimental protocol.

[0074] Sample AC 4. A film of the active composition was prepared by mixing 1.35 grams of DOW Sylgard™ 184 Fluid A (polydimethylsiloxane, PDMS) with 0.15 grams of DOW 184 Fluid B (dimethyl, methylhydrogen siloxane copolymer) as a crosslinker for 10 minutes. Then, 0.015 g of rhodamine-zeolite Sample S2 was added to the formulation at room temperature, and mechanical mixing was continued for an additional 10 minutes. After a homogeneous dispersion was obtained, a degassing process was carried out under vacuum for 15 minutes. The resulting formulation was spread onto a glass substrate with a doctor blade to a thickness of 50 microns, and the sample was heated at 100°C for 30 minutes to accelerate the polymerization process.

[0075] A reference PDMS film without markers was also prepared applying the same experimental protocol.

[0076] Sample AC 5. A film of the active composition was prepared by mixing 1.45 grams of SunChemical COMPOST LAM ADH (aliphatic polyisocyanate-based polyurethane, PU) with 0.05 grams of alcohol dehydrogenase catalyst. Then, 0.015 grams of Rhodamine-Zeolite Sample S2 was added at room temperature, and the dispersion was stirred by mechanical mixing for 15 minutes. The resulting formulation was spread onto a glass substrate at a thickness of 50 microns using a doctor blade, and the crosslinking reaction was promoted at room temperature.

[0077] A reference PU film without marker was also prepared applying the same experimental protocol.

[0078] Sample AC 6. 1.5 g of LyondellBasell low-density polyethylene (LDPE), grade LUPOLEN® 2420, was dissolved in 8.5 g of toluene at a boiling temperature of 110° C. After the polymer was dissolved, 0.015 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature, and the dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously by mechanical mixing for 1 hour.

[0079] The resulting formulation was spread onto a Teflon foil with a thickness of 50 microns using a doctor blade, and solvent evaporation was accelerated at 50°C. A composite film containing 1% by weight of the marker in the polymer matrix was obtained. A reference LDPE film without the marker was also prepared applying the same experimental protocol.

[0080] Sample AC 7. 1.5 g of atactic polystyrene (PS), grade EDISTIR® N1910 from Versalis (ENI), was dissolved in 8.5 g of toluene at a boiling temperature of 110°C. After the polymer was dissolved, 0.015 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature. The dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously stirred by mechanical mixing for 1 hour. The resulting formulation was spread onto Teflon® foil with a doctor blade to a thickness of 50 microns, and solvent evaporation was accelerated at 50°C. A composite film containing 1% by weight of marker in the polymer matrix was obtained. A reference PS film without marker was also prepared using the same experimental protocol.

[0081] Sample AC 8. 1.0 g of GoodFellow polylactic acid (PLA) (MFR=8) was dissolved in 9.0 g of chloroform at a boiling temperature of 61°C. After the polymer was dissolved, 0.01 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature, and the dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously stirred by mechanical mixing for 1 hour. The resulting blend was spread onto Teflon foil with a doctor blade to a thickness of 50 microns, and solvent evaporation was accelerated at 40°C. A composite film containing 1% by weight of marker in the polymer matrix was obtained. A reference PLA film without marker was also prepared using the same experimental protocol.

[0082] Sample AC 9. 1.0 g of GoodFellow's polyhydroxybutyrate (PHB) was dissolved in 20.0 g of chloroform at a boiling temperature of 61°C. After the polymer was dissolved, 0.03 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature, and the dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously stirred by mechanical mixing for 1 hour. The resulting blend was spread onto Teflon foil with a doctor blade to a thickness of 50 microns, and solvent evaporation was accelerated at 40°C. A composite film containing 3% by weight of marker in the polymer matrix was obtained. A reference PHB film without marker was also prepared using the same experimental protocol.

[0083] Sample AC 10. 1.0 g of GoodFellow's 2% polyhydroxybutyrate / polyhydroxyvalerate (PHBV) was dissolved in 20.0 g of chloroform at a boiling temperature of 61°C. After the polymer was dissolved, 0.03 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature, and the dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously stirred by mechanical mixing for 1 hour. The resulting blend was spread onto Teflon foil at a thickness of 50 microns using a doctor blade, and solvent evaporation was accelerated at 40°C. A composite film containing 3% by weight of marker in the polymer matrix was obtained. A reference PHBV film without marker was also prepared using the same experimental protocol.

[0084] Sample AC 11. 1.0 g of Kuraray polyvinyl alcohol (PVOH): Grade Exceval® AQ-4104 was dissolved in 9.0 g of distilled water at a boiling temperature of 100°C. After the polymer was dissolved, 0.01 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature, and the dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously stirred by mechanical mixing for 1 hour. The resulting formulation was spread onto a glass substrate with a doctor blade to a thickness of 50 microns, and water evaporation was accelerated at 50°C. A composite film containing 1% by weight of marker in the polymer matrix was obtained. A reference PVOH film without marker was also prepared using the same experimental protocol.

[0085] Sample AC 12. Hydroxypropylated starch ether (STARCH) from SOLAM, grade SOLCOAT P85, 1.0 g, was dissolved in 9.0 g of distilled water at a boiling temperature of 100°C. After the polymer was dissolved, 0.01 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature, and the dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously stirred by mechanical mixing for 1 hour. The resulting formulation was spread onto a glass substrate with a doctor blade to a thickness of 50 microns, and water evaporation was accelerated at 40°C. A composite film containing 1% by weight of marker in the polymer matrix was obtained. A reference STARCH film without marker was also prepared using the same experimental protocol.

[0086] Example AC 13 (Blend 1). 0.7 g of GoodFellow's polylactic acid (PLA) (MFR=8) and 0.3 g of GoodFellow's 2% polyhydroxybutyrate / polyhydroxyvalerate (PHBV) were dissolved in 18.0 g of chloroform at a boiling temperature of 61°C. After the polymer was dissolved, 0.05 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature, and the dispersion was mixed by bath sonication at room temperature for 30 minutes and vigorously stirred by mechanical mixing for 1 hour. After casting the solution, a composite film containing 3 wt% marker in the polymer matrix was obtained. A reference PLA / PHBV film without marker was also prepared using the same experimental protocol.

[0087] Example AC 14 (Blend 2). 0.7 g of polyvinyl alcohol (PVOH) grade Exceval® AQ-4104 from Kuraray and 0.3 g of hydroxypropylated starch ether (STARCH) grade SOLCOAT P85 from SOLAM were dissolved in 9.0 g of distilled water under vigorous stirring at 90°C. After the polymer was completely dissolved, 0.01 g of rhodamine-zeolite sample S2 was added to the polymer solution at room temperature (RT), and the dispersion was mixed by bath sonication at RT for 30 minutes and vigorously stirred by mechanical mixing at RT for 1 hour. The resulting blend was spread onto a glass substrate at a thickness of 50 microns using a doctor blade, and water evaporation was accelerated at 50°C. A reference PVOH / starch film without marker was also prepared using the same experimental protocol.

[0088] Example AC 15. 49 g of polyethylene low-density powder of ≦400 microns purchased from Alfa Aesar was compounded with 1 g of rhodamine-zeolite (Sample S2) via melt blending for 5 minutes using a Lab Two Roll Open Mixing Mill (Battaggion). The rolling conditions were as follows: front roller temperature = 130°C; back roller temperature = 80°C; roll speed = 33 rpm. The resulting compounded material was compression molded using a laboratory press (Gibitre Instruments) at P = 230 bar and T = 175°C for 5 minutes to obtain a sheet (thickness ≈ 200 μm) containing 2% by weight of marker. A reference polyethylene sheet without marker was also produced according to the same experimental protocol.

[0089] Example AC 16. 49 g of polylactic acid (grade NatureWorks 2003D) was compounded with 1 g of rhodamine-zeolite (sample S2) via melt blending for 5 minutes using a Lab Two Roll Open Mixing Mill (Battaggion). The rolling conditions were as follows: front roller temperature = 155 ° C; back roller temperature = 125 ° C; roll speed = 33 rpm. The resulting compounded material was compression molded using a laboratory press (Gibitre Instruments) at P = 230 bar and T = 190 ° C for 5 minutes to obtain a sheet (thickness ≈ 200 μm) containing 2% by weight of marker. A reference polylactic acid sheet without marker was also produced according to the same experimental protocol.

[0090] Example AC 17. 48.5 g of GoodFellow's polyhydroxybutyrate / polyhydroxyvalerate 2% (PHBV) was compounded with 1.5 g of rhodamine-zeolite (Sample S2) via melt blending for 5 minutes using a Lab Two Roll Open Mixing Mill (Battaggion). The rolling conditions were as follows: front roller temperature = 170 ° C; back roller temperature = 145 ° C; roll speed = 33 rpm. The resulting compounded material was compression molded using a laboratory press (Gibitre Instruments) at P = 230 bar and T = 190 ° C for 5 minutes to obtain a sheet (thickness ≈ 200 μm) containing 3% by weight of marker. A reference PHBV sheet without marker was also produced according to the same experimental protocol.

[0091] Example AC 18 98 g of acrylonitrile butadiene styrene ABS (grade Terluran® GP-22 manufactured by INEOS STYROLUTION) was compounded with 2 g of rhodamine-zeolite (sample S5) via melt blending for 5 minutes using a Lab Bench Top Two-Roll Mill (LabTech Engineering). The rolling conditions were as follows: front roller temperature = 175°C; back roller temperature = 170°C; roll speed = 10 rpm. The resulting compounded material containing 2% by weight of marker S5 was molded into a sheet (500 μm thick). A reference ABS sheet without marker was produced according to the same preparation protocol.

[0092] [Table 6A]

[0093] [Table 6B]

[0094] Marker and matrix optical characterization Description of the apparatus. For the measurements, a Horiba FluoroMax® Plus spectrofluorometer was used. A continuous light source P focused onto the entrance slot of the excitation monochromator. oA 150W ozone-free xenon arc lamp was applied. The instrument was based on two Czerny-Turner monochromators, which dispersed the incident light through their reflection gratings. Optical spectra were obtained by rotating the gratings and recording the intensity values at each wavelength. The entrance and exit ports of each monochromator contained continuously adjustable slits to control the spectral resolution, and the intensity of the fluorescence signal was recorded by a photomultiplier tube. A solid sample holder equipped with an adjustable goniometer was used to test the polymer products in the form of marker-doped films or plates. A sample setting with a 60° angle between the incident and specularly reflected beams was used to prevent the excitation beam from entering the emission slits, thereby avoiding stray light interference. FluorEssence™ analysis and measurement software was used for data acquisition and processing.

[0095] Description of sample characterization protocol To detect the presence of the dye inside the polymer matrix, the marker excitation and emission peaks in the polymer matrix were compared with those of a reference sample (polymer matrix without marker) and the pure marker. By taking into account the fluorescence of the dye, the sample performance was studied as the ratio between the fluorescence intensity I of the active composition, subtracting the excitation at 540 nm, and the fluorescence intensity I0 of the pure polymer matrix without dye. According to the applied protocol, the presence of the marker was considered detectable if a value greater than 2 was determined for the I / I0 ratio. Table 5 below reports the recorded values for all tested samples.

[0096] [Table 7]

Claims

1. A dye-exchange zeolite marker containing zeolite and a dye, a) The zeolite is in the form of a powder having an average particle size characterized by an X90 value contained in 0.5 to 50 μm and a pore size contained in 4 Å to 12 Å. b) The dye is an organic cation molecule selected from the group consisting of rhodamine B, tetramethylrhodamine isothiocyanate-dextran, rhodamine 6G, rhodamine B isothiocyanate, and rhodamine 19 percolate. c) The amount of dye is contained in 0.05% to 1% by mass relative to the mass of the zeolite. Dye-exchangeable zeolite marker.

2. The dye-exchange zeolite marker according to claim 1, wherein the zeolite is faujasite-type zeolite (FAU) or mordenite zeolite (MOR).

3. The dye-exchange zeolite marker according to claim 1, wherein the zeolite has a surface that is modified or functionalized with an alkoxysilane derivative.

4. A dye-exchange zeolite marker according to claim 1, obtained via a cation exchange reaction between at least one cation of the zeolite and at least one cation of the dye.

5. A composition comprising a dye-exchange zeolite marker according to claim 1 dispersed in a polymer matrix, wherein the polymer matrix is ​​selected from polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS) and their copolymers and functionalized polymers, acrylic, acrylic-styrene, acrylic-vinyl and alkyl copolymers, urethane-acrylic, urethane, polyurethane, epoxy, siloxane and polysiloxane, phenolic resin, poly[ethene-co-(vinyl alcohol)] (EVOH), poly(vinyl alcohol) (PVAL), poly(lactic acid-coglycolic acid) (PLGA), polyethylene glycol (PEG), poly(vinyl acetate) (PVAC), aqueous or water-dilutable latex, polylactic acid (PLA), aliphatic or aromatic co-polyesters, and natural polymers.

6. The composition according to claim 5, wherein the dye-exchange zeolite marker is present in an amount of 0.1 to 10% by mass relative to the polymer matrix.

7. The composition according to any one of claims 5, wherein the polymer matrix is ​​treated in the form of a coating, film, lacquer, frame, three-dimensional element, pellet, or sheet.

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