ITUB20160663A1 - Composition indicating humidity including leuco dyes - Google Patents

Description

COMPOSITION INDICATOR OF HUMIDITY INCLUDING LEUCO COLORANTI

DESCRIPTION

FIELD OF THE INVENTION

The present invention relates to moisture indicator compositions comprising thermo-fusible adhesives (commonly referred to in the sector with the English term "hot-melt") and leuco dyes. By contact with water or with fluids containing water, the above moisture indicator compositions change their color from a colorless state to a colored state or from a first colored state to a second colored state, having said second colored state a color different from the first. .

Therefore the compositions described in the present invention can be used as indicators of the presence of humidity and / or aqueous fluids in various applications, for example in sanitary absorbent articles, in absorbent articles for medical use, in absorbent articles for the packaging of food products , in packaging items and, in general, for devices for detecting the presence of water in confined environments. The invention therefore also relates to said articles.

STATE OF THE PRIOR ART

In various fields of use and in articles related to them, there is a need to signal to the user that a certain object or article, which is initially in a substantially dry / anhydrous state, has come into contact with water in the liquid phase or with fluids containing water or that it now contains water or aqueous fluids that were not initially present. Examples of applications of this type can be some foods which are preferably packaged in a dry state and must be stored in this state, some chemicals or medicines which can be degraded by water or disposable sanitary napkins which must be changed, when they become full of urine or other body fluids containing water.

All systems that can signal contact with water or the presence of water in the liquid phase or fluids containing water to a user are herein collectively grouped under the name of "humidity indicators". A typical signal through which many humidity indicators indicate the presence of water can be a color variation, from a first color that the humidity indicator has in the initial state, substantially anhydrous, of the article on which it is applied, to a second color, different from the first, in the wet state.

One of the two different colors between which the humidity indicator changes, due to contact with water or aqueous fluids, can also be white or a substantially colorless state. In some fields of use, and in the articles related to them, a humidity indicator that initially (or in the dry state) is white or substantially colorless, can also be the preferred choice, provided that these indicators are naturally capable of turning to a color. visible once they come into contact with a liquid containing water; typical examples are food packaging or sanitary absorbent articles. In both these exemplary cases, an initial white or substantially colorless appearance of the moisture indicator composition is generally linked, in the perception of most users, to concepts of "hygiene", "cleanliness" or "good state of conservation", and therefore meets a greater approval by the same.

Therefore, the moisture indicator compositions can comprise a dye capable of changing its appearance, for example appearing and disappearing from sight or, in general, changing its color, as a consequence of having come into contact - together with the article with which the moisture indicator composition is associated - with water in the liquid phase or with fluids containing water as the main component. For example, in the case of sanitary absorbent articles, said fluids containing water as the main component are the physiological body fluids, such as urine, liquid stools, menstrual blood and the like and the appearance of the color change here indicates to the user the need for change the disposable sanitary napkin, which is now out of stock. In other applications, for example in the packaging of food or medicinal substances sensitive to water, the appearance of the color change indicates a poor state of conservation of the product and therefore the need not to use it.

However, the colored active ingredients most used today as moisture indicators for sanitary absorbent articles have a strongly colored initial appearance; in particular in most cases they have a yellow color in the initial anhydrous state, ie before coming into contact with water or physiological fluids, while they take on a different color, for example blue or violet, after being wet.

Therefore, in the fields of application indicated above, there is a continuing need for moisture indicators that can provide a range of various final colors, in the presence of water, preferably starting from an initial dry state in which the moisture indicator is colorless or white. . There is also a continuous need to identify new technical ways of applying these humidity indicators to the articles with which they are associated, which allow an improvement in the production processes relating to this application.

The aim of the present invention is therefore to offer a newly conceived moisture indicator composition, capable of simultaneously satisfying both the above-mentioned market needs.

In particular, a first object of the invention is to offer a moisture indicator composition which in the anhydrous state is colorless or white and in the wet state instead presents a clear and clearly visible color.

A second object of the invention is then to offer a composition indicating humidity which allows to simplify and improve the process of applying the composition itself to the various articles with which it can be associated, in particular by giving said composition: an adhesion capacity compared to the most wide typology of substrates used in the articles to which it must be associated, in particular paper, cardboard and plastic materials of all kinds; high adhesion speed; high storage stability over time without causing unwanted color changes; said composition being moreover preferably free of flammable, volatile or toxic solvents.

SUMMARY DESCRIPTION OF THE INVENTION

1) The needs and objects outlined above are achieved, according to the present invention, by means of a moisture indicator composition which comprises a matrix consisting of a hot-melt adhesive, at least one leuco dye and at least one color developer. Other preferred features of the moisture indicator composition of the present invention are defined in the secondary claims. The invention also comprises an article to a structural component of which said composition is applied; for example said article can be a packaging; an absorbent mattress or sheet or operating drape for medical use; a product for covering and protecting wounds; an absorbent pad or sheet for food products.

However, the use of the composition of the invention in articles for the care of the child or the care of the woman is expressly excluded from the scope of protection of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the present invention, in order to respond positively to the needs illustrated above, it has been hypothesized to use as an indicator of humidity a leuco dye (i.e. colorless) or a mixture of leuco dyes, which turn to a visible color when they come into contact with water or with physiological fluids containing water, said dye being dispersed in a matrix consisting of a hot-melt adhesive and with the further addition of a color developer.

In the known art, the incorporation of humidity indicators, including some leuco dyes, within various types of vehicle / binder matrices which are liquid at room temperature, such as for example inks (based on solvents or water), has already been disclosed, liquid adhesives (based on solvents or water), paints, and other similar materials. On the contrary, however, the incorporation of leuco dyes or mixtures of leuco dyes as humidity indicators within a solid matrix consisting of a hot-melt adhesive has never been detected in the prior known art.

Although this incorporation must be carried out with a very careful choice of the chemical nature of all the components of the hot-melt adhesive matrix, so as not to compromise the characteristics of the leuco dye, this hot-melt matrix nevertheless offers many advantages typical of hot adhesives. -melt: for example, simple and quick application starting from the molten state, strong adhesion on most possible substrates, even those difficult to glue such as plastic films, such as polyolefin plastic films that form absorbent sanitary articles or various types of packaging, absence of toxic, volatile or flammable solvents, very high gluing speed, absence of water (which obviously could prematurely trigger the development of colors or deteriorate the product on which the composition is applied) in all phases of preparation and application of the composition indicating humidity and other positive characteristics typ iche of hot-melt adhesives.

Definitions

"Child Care or Women's Care Article" means products and / or methods related to absorbent and / or non-absorbent disposable articles including incontinent adult garments, baby bibs and diapers, absorbent baby panties, wipes for the care of babies and children; feminine sanitary napkins, adult incontinent pads, interlabial pads, panty liners, pessaries, sanitary nappies, tampons and tampon applicators, and / or cleansing wipes

As used herein, the term "dye" refers to any coloring material, ink, inks that contain dyes or pigments, pH indicators, chemical indicators and metal chelators, oxidation or reduction indicators (redox indicators), ionchromic dyes, dyes aiochromic dyes, solvatochromic dyes, hydrochromic dyes, thermochromic dyes, electrochromic dyes, biochromic dyes that change color upon contact with a specific biological component of an exudate, and any material that has the ability to change its color or the color of the environment in which it is inserted under certain specific conditions, and any possible combination of them.

As used here, the term "permanent dye" means a dye that retains its color regardless of environmental factors or that does not change its color in any situation, such as for a change in pH or contact with a liquid or specific components of that liquid, or for high humidity, or for high or low temperatures.

"Which includes" or "comprising (i)" are generic terms which specifically indicate the presence of what follows these terms in the text, but which do not preclude the presence of other characteristics, for example elements, stages, components already known in the prior art or reveal yourself here.

Leuco Dyes

The moisture indicator compositions which are used in the present invention comprise at least one leuco dye and at least one color developer, formulated within a matrix formed by a hot-melt adhesive. In this way the moisture indicator composition changes its appearance, i.e. it changes color, appears, disappears from view, etc. following contact, inside the article in which the moisture indicator composition is inserted, with water in the liquid phase or with fluids mainly formed by water such as physiological body fluids. In a particular variant of the present invention, the moisture indicating compositions formulated according to the present invention, following contact with water in the liquid phase or with fluids mainly formed by water such as physiological body fluids, change their color from an initial state to dry condition which is white or substantially colorless, to a colored state after being wetted by a liquid aqueous phase, or vice versa.

A leuco dye (from the Greek LEUKOS = WHITE) is a dye whose molecule can take on two chemical forms, one of which is substantially colorless. As mentioned above briefly and in general for all dyes, also leuco dyes are often classified according to the different chemical mechanisms which cause the dye molecule to change from its substantially colorless chemical form (LEUCO) to a colored form. Therefore in the literature one can find leuco dyes classified in families, such as for example the thermochromic leuco dyes, in which the color variation from a colorless to a colored state (or vice versa) is caused by a temperature variation; leuco photochromic dyes in which the change in color from a colorless to a colored state (or vice versa) is caused by light; solvatochromic leuco dyes in which the color change from a colorless to a colored state (or vice versa) is caused by contact with particular solvents and above all with a certain solvent having a certain defined polarity; leuco biochromic dyes in which the color change from a colorless to a colored state (or vice versa) is caused by contact with specific biological entities or components; leuco redox dyes in which the color change from a colorless to a colored state (or vice versa) is caused by a chemical oxidation or reduction; electrochromic leuco dyes in which the color change from a colorless to a colored state (or vice versa) is caused by the passage of an electric current; leuco ionchromic dyes in which the color variation from a colorless to a colored state (or vice versa) is caused by the interaction with specific ions and / or by a variation in their concentration; the aiochromic leuco dyes in which the color change from a colorless to a colored state (or vice versa), according to the primitive literal meaning of the word (from the Greek HALOS = SALE), is caused by interactions with specific salts, and the like.

However, it is necessary to note that in the current common technical-scientific jargon, today the term "aiochromic" is often used for dyes and for leuco dyes which change from an initial color (which is colorless, in the case of leuco dyes) to a different state colored due to a change in the concentration of hydrogen ions. In this slightly different meaning, therefore, the aiochromic leuco dyes constitute a subclass of the more general ionchromic leuco dyes, when the ions whose concentration variation causes the change of the leuco dye from a colorless to a colored state or vice versa, are hydrogen ions.

Without being bound by any theory, a color developer is any substance which, interacting or reacting with the leuco dye, causes its color to change from a colorless to a colored state or vice versa, regardless of the chemical nature of the color. of the developer (s) and regardless of the nature of the chemical or physical mechanism that activates and causes the color variation.

Since the compositions disclosed in the present invention are intended to be used as indicators of humidity, in contact with water in the liquid phase or with aqueous fluids, it is obvious that, only for clarity and without this implying a limitation of the scope of protection of the present invention, the following general scheme of how the compositions of the present invention probably work is applied: the contact between the compositions disclosed herein and water in the liquid phase or aqueous fluids, such as biological fluids, constitutes a "trigger event" which initiates the 'interaction or reaction between the leuco dye (s) and the developer (s) that is / are present in the composition, which determines the change in appearance from a colorless to a colored state (or vice versa) of the composition itself, regardless of the nature of the chemical or physical mechanism of said interaction or reaction, and regardless of the chemical nature of the developer (s) (the).

In a particular variant of the present invention, the color developer may act as a Bronsted or Lewis acid, or as a compound that forms strong hydrogen bonds, thereby causing the coloration of a colorless leuco dye to a colored dye.

For example, a particular leuco dye is the crystal violet lactone, a phthalide-based dye (spiro-lactone) hereinafter abbreviated to CVL and chemically named 3,3-bis (pdimethylaminophenyl) -6-dimethylaminophthalide or 6 - (dimethylamino) -3,3-bis- [p- (dimethylamino) phenyl] phialide, also identified with CAS number 1552-42-7.

CVL is essentially colorless when its structure, which includes a five-unit lactone ring, remains intact. When it reacts with a suitable developer, such as certain molecules that are Lewis acids capable of accepting electrons, the lactone ring typically opens, giving rise to a new, highly conjugated molecular form of CVL, which possesses multiple resonance structures. This highly conjugated open-ringed CVL molecule now appears blue on naked eye observation. The ring opening reaction in the CVL occurs thanks to the dissociation of the C-0 bond in the presence of a proton donor or an electron doublet acceptor or even compounds capable of forming strong hydrogen bonds. This ring opening reaction causes the formation of the highly conjugated, open ring blue cation. This colorless to deep blue reaction makes CVL an interesting active dye component, not only in moisture indicator compositions, but also for example as a photopolymerization initiator and as the main active dye in many thermochromic materials.

As mentioned, the opening of the lactone ring in the CVL derives from the reaction with a suitable molecule, which can act as a color developer. Many developers have the ability to pass one or more protons to the CVL or to accept electrons from the CVL molecule. This developer acidity leads to the opening of the CVL ring which in turn causes the color change from colorless to blue. Without being tied to a specific theory, the colorless form of CVL, with the closed ring, is also said to be its spiropiranic form, where the "spiro" carbon is hybridized sp3, and the five-unit lactone ring is closed and intact. This sp3 hybridization of the spiro-carbon limits the conjugation of the CVL such that the shape of the CVL with the closed loop appears substantially colorless to the naked eye. However, when an interaction occurs with a molecule capable of releasing one or more protons, such as a Bronsted acid, or with a molecule capable of accepting electrons, such as a Lewis acid, the lactone ring of the CVL opens due to the breaking of the bond between the oxygen atom and the spiro-carbon atom. Following the opening of the ring, the spiro-carbon now becomes sp2 hybridized and multiple resonance structures become possible within this highly conjugated molecule. Due to this increased resonance and this conjugation of bonds within the CVL structure with the open ring, the CVL molecule becomes strongly colored blue. It should be noted that mixtures of Bronsted and Lewis acids can be used in the same formula in order to improve the properties of the composition.

Not only does the release of protons lead to the opening of the CVL ring, but also molecules capable of forming strong hydrogen bonds and / or that are Lewis acids, can cause the CVL ring opening reaction. In addition to these compounds, certain cations, such as mercury and copper, are also known to be capable of giving a dark blue color, thanks to the formation of complexes with the open-loop CVL structure.

For a generic developer, who is a proton donor, the reaction is schematized in the following illustration, in which the structure on the left, with the five-unit lactone ring is colorless, while the protonated structure on the right is blue:

Also other phthalide leuco dyes, especially those having a basic molecular structure similar to that of CVL, can change from a colorless to a strongly colored state through a very similar chemical mechanism and can similarly be used in the present invention. Preferred leuco dyes of this type are for example heterocyclic compounds analogous to CVL, in particular those with indole and pyridine rings, an example of which is 3- (1,2-dimethyl-3-indolyl) -3- [4- ( diethylamino) -2-methylphenyl] phialide, also identified with CAS number 36499-49-7 and also known in industry under the trade name of NC BLUE 3.

Other species of leuco dyes, in turning to a colored state, work according to different chemical mechanisms. For example, the color change from colorless to colored and vice versa in the class of leuco dyes called leuko-quinones is activated by redox reactions. Other families of leuco dyes are activated by light, and such families include leuco derivatives of the oxazine, thiazine and phenazine dyes. Other leuco dyes can turn from a colorless state to a colored state when they are activated by the presence and concentration of certain specific ions and therefore by the presence of certain chemical compounds (such as acids, salts, etc.) capable of releasing particular active ions. These leuco dyes are known under the names of ionochromic or aiochromic. In a particular variant of the present invention, these active ions are hydrogen ions, and therefore the aforementioned ionchromic / halochromic leuco dyes can also be used as pH indicators. Examples of ionchromic / halochromic leuco dyes of this type, usable in the present invention, include for example thymolphthalein, alpha-naphtholphthalein, 4, 5,6,7, -tetrabromo-phenolphthalein, 3 ', 3 ", 5 ', 5 "-tetrabromo-phenolphthalein, ocresolphthalein, phenolphthalein, xylenolphthalein, guaiacolphthalein, ethyl-bis- (2,4-dinitrophenyl) acetate, bis- [9- (diethylamino) -5H-benzo [a] phenoxiazin-5-iminium] sulfate (or NILE BLUE A), quinoline blue, heptamethoxi red, 3-nitrophenol, pinachrome.

Further specific leuco dyes, in addition to the CVL and those mentioned above, which can be usefully used in the present invention, may include for example other leuco phthalide dyes, leuco triarylmethane dyes, leuco thiazine, oxazine and phenazine dyes; leuco quinones, leuco fluoranic dyes etc. Examples of such dyes include for example:

(1) leuco dyes based on triarylmethane, for example 3,3-bis (pdimethylaminophenyl) phialide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phialide, 3- ( p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylamino phthalide, 3,3-bis- (l , 2-dimethylindol-3-yl) -6-dimethylamino phthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylamino phthalide, 3,3-bis (2-penylindol-3-yl ) -6-dimethylamino phthalide, 3-p-dimethylaminophenyl-3- (1-methoxipyrrol-3-yl) -6-dimethylamino phthalide etc.

(2) diphenylmethane-based leuco dyes, for example 4,4'-bisdimethylaminobenzhydryl benzyl ether, N-halophenyl-leuco-auramine, N-2,4,5-trichlorophenyl-leuco-auramine etc.

(3) leuco lactam-based dyes, for example rhodamine-B-aniline lactam, rhodamine- (p-nitroanilino) lactam, rhodamine- (o-nitroanilino) lactam etc.

(4) leuco fluorane-based dyes, for example 3-di-methylamino -7-methoxy fluorane, 3-di-ethylamino-6-methoxy fluorane, 3-diethylamino-7-methoxy fluorane, 3-di- ethylamino-7-chloro fluorane, 3-diethylamino-6-methyl-7-chloro fluorane, 3-di-ethylamino-6,7-di-methyl fluorane, 3- (N-ethyl-p-toluidino) - 7-methyl fluorane, 3-di-ethylamino-7- (N-acetyl-N-methylamino) fluorane, 3-di-ethylamino-7- (N-methylamino) fluorane, 3-di-ethylamino-7- di-benzylamino fluorane, 3-di-ethylamino-7- (N-methyl-N-benzylamino) fluorane, 3-di-ethylamino-7- (N-chloroethyl-N-methylamino) fluorane, 3-di- ethylamino-7-N-di-ethylamino fluorane, 3- (N-ethyl-p-toluidin) -6-methyl -7-phenylamino fluoran, 3- (N-ethyl-p-toluidin) -6-methyl- 7- (p-toluidin) fluoran, 3-di-ethylamino-6-methyl-7-phenylamino fluoran, 3-di-butylamino-6-methyl-7-phenylamino-fluoran, 3-diethylamino-7- (2 -carbomethoxy-phenylamino) fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-phenylamino fluorane, 3-pi rrol idin-6-methyl 1-7-phenylamino fluorane, 3-piperidin-6-methyl-7-phenylamino fluoran, 3-diethylamino-6-methyl-7- (2,4-di-methylamino) fluorane, 3-di-ethylamino-7- (o-chlorophenylamino) fluorane, 3-di-butylamino-7- (o-chlorophenylamino) fluorane, 3-pyrrolidine-6-methyl-7- (p-butylphenylamino) fluoran, 3- (N-methyl-N-n-amyloamino) -6-methyl-7-phenylamino fluorane, 3- (N-ethyl-N-namyloamino) -6-methyl-7-phenylamino fluorane, 3- (N-ethyl -N isoamylamino) -6-methyl-7-phenylamino fluorane, 3- (N-methyl-N-nesylamino) -6-methyl-7-phenylamino fluorane, 3- (N-ethyl-N-n-hexylamino) -6 -methyl-7-phenylamino fluorane, 3- (N-ethyl-N- [3-ethylhexylamino]) - 6-methyl-7-phenylamino fluorane etc.

Further examples of leuco dyes usable in the present invention may include malachite lactone green, indigo leuco, methylene blue leuco, methylene blue leuco benzene, etc. The leuco dyes usable in the present invention are not limited to those exemplified above, and one or two or more dyes, mixed together, can be used in the present invention.

The moisture indicator compositions of the present invention may contain from about 0.01% by weight to about 20% by weight of a leuco dye or a mixture of leuco dyes. Said moisture indicator compositions may also contain other non-leuco colored compounds. These other colored compounds can be a permanent dye, an ink, a pigment such as titanium dioxide or aluminum silicates or zinc oxide, a pH indicator, a redox indicator, and combinations thereof. In the latter cases, the total amount of leuco dyes plus other colored compounds within the moisture indicator composition can vary between about 0.02% by weight and about 30% by weight. In some cases, it may be advantageous to include an oil-soluble or water-soluble permanent dye. Some examples of oil-soluble permanent dyes include D & C Yellow No. 11, D & C Red No. 17, D & C N. Red 21. D & C Red No. 27, D & C Purple No. 2, D & C Green No. 6, and D & C Orange No. 5. Other permanent dyes include red pigment 146 (CAS # 5280-68-2), red pigment 122 (CAS # 980-26-7), orange pigment 16 (CAS # 6505-28-8), red beet extract, and beta -carotene.

Some representative examples of activated liquid dyes that can be used in the practice of the present invention include: Malachite green, brilliant green, crystal violet, erythrosin B, methyl green, 2D methyl violet, picric acid, naphthol yellow S, quinaldine red, eosin Y, methanyl yellow, purple m-cresol, blue thymol, blue xylenol, fuchsin base, eosin B, 4-p-aminophenol (azo) benzenesulfonic acid sodium salt, cresol red, red m-cresol, purple m-cresol, martius yellow , Phloxin B, Phloxin acid, yellow methyl, bromophenol blue, Congo red, methyl orange, violet crystalline lactone, ethyl-bis (2,4-dinitrophenyl) acetate, bromochlorophenol blue (soluble in water or free acid form), orange di ethyl, flourocene WS, bromocresol green, chrysoidine, sodium salt of methyl red, alizarin red S-H20, cochineal, chlorophenol red, bromocresol purple, 4-naphtha, alizarin, nitrazine yellow, bromothymol blue, bright yellow, neutral red, red acid alico, phenol red, 3-Nitro phenol, orange II, phenolphthalein, ocresolphthalein, Nile blue A, thymolphthalein, aniline blue WS, alizarin GG yellow, mordant orange, tropaolin 0, orange G, acid fuchsin, thiazole yellow G, indigo carmine, cresol red, methyl red, p-nitrophenol, and alizarin yellow R. In some cases, it is advantageous to use the free acid form, the free base form or salt form of coloring substances, or mixtures thereof.

Other water-soluble dyes may include FD & C Blue No. 1, FD & C Blue No. 2, FD & C Green No. 3, FD & C Red No. 40, FD & C Red No. 4, FD & C Yellow No . 5, FD & C Yellow No. 6, C.I. Food Blue 5, and C.I. Food Red 7, D & C Yellow No. 10, D & C Yellow No. 7, D & C Yellow No. 2, D & C Yellow No. 8, D & C Orange No. 4, D & C Red No 22, D & C Red No. 28, D & C Red No. 33, D & C Green No. 8, D & C Green No. 5, D & C Brown No. 1, and a combination thereof. Preferably, the dye is soluble in the moisture indicating composition, but, as noted in some instances, the dye may function as intended by suspending or dispersing it homogeneously within the moisture indicating composition.

Other suitable fluid dyes include water-soluble dyes such as direct dyes, acid dyes, basic dyes, and various solvent-soluble dyes. Dispersed or suspended pigment dyes may also be employed in these moisture indicator compositions (liquid activated formulations). Examples include, but are not limited to, CI Acid Yellow 73, C.I. Solvent Yellow 94, C.I. Acid Yellow 74, C.I. Solvent Orange 32, C.I. Solvent Red 42, C.I. Acid Orange 11, C.I. Solvent Red 72, C.I. Pigment Orange 39, C.I. Solvent Orange 18, C.I. Acid Red 87, C.I. Solvent Red 43, C.I. Pigment Red 90: 1, C.I. Solvent Red 44, C.I. Solvent Red 45, C.I. Solvent Orange 16, C.I. Acid Red 91, CI Acid Red 98, CI Acid Red 92, C.I. Solvent Red 48, CI Pigment Red 174, Pigment Red 146 (CI No. 12485, CAS # 5280-68-2)), Pigment Red 122 (CAS # 980-26-7), Pigment Red 112 (CAS # 6535-46 -2), Pigment Red 101 (CAS # 1309-37-1), Pigment Orange 34 (CAS # 15793-73-4, Pigment Orange 16 (CAS # 6505-28-8), Pigment Green 7 (CAS # 1328- 53-6), Pigment Blue 15: 2 (CAS # 12239-87-l), Pigment Blue 15 (CAS # 147-14-8), Pigment Black 7 (CAS # 1333-86-4), Pigment Red 176, Pigment Red 200, Pigment Red 254, Pigment Red 48: 1, Pigment Red 48: 2, Pigment Red 48: 3, Pigment Red 52, Pigment Red 52: 1, Pigement Red 57: 1, Pigment Red 63: 1, Pigment Violet 19, Pigment Violet 23, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 74, Pigment Yellow 83, C.I. Acid Red 95, C.I. Solvent Red 73, C.I. Pigment Red 191, C.I. Acid Red 51, C.I. Food Red 14, C.I. Pigment Red 172, C.I. Solvent Red 140, C.I. Acid Red 93, C.I. Solvent Red 47, C.I. Acid Red 94, C.I. Solvent Red 141, C.I. Mordant Violet 25, C.I. Solvent Orange 17, C.I. Solvent Red 46, D&C Red 27 (C.I. 45410: 1), D&C Orange 5 (C.I. 45370: 2), and their combinations. Most preferred fluid dyes are selected from the group consisting of D&C Red 27, D&C Orange 5, and combinations thereof.

Other suitable dyes may include bromopyrogallol red, bromoxylenol blue, methylene blue, monoazo dyes such as alizarin acid N, monoazo pyrazoline dyes (such as 34 yellow acid), diazo dyes (such as 24 black acid), anthraquinone dyes (such as black acid 48), amphoteric anthraquinone dyes (such as blue acid 45), triphenylmethane dyes (such as acid fuchsin), phthalein-like dyes (such as ocresolphthalein), xanthene dyes (such as 2'7 'dichlorofluorescein eosin B), aromatic heterocyclic acridine (such as acridine orange), diphenylmethane dyes (such as auramine 0), triphenylmethane dyes (such as basic fuchsin), cationic thiazine dyes (blue C), cationic anthraquinone dyes such as base blue 47, phthalocyanine type dyes (such as strazon orange G), anthraquinone type (such as alizarin), neutral complex dyes (such as Azure A eosin), terpene type dyes (such as trans-beta-carotene), as well as combinations including at least one of the previous dyes.

Examples of dyes further include, but are not limited to, organic dyes, inorganic pigments, colored macromolecules, nanoparticles and colored materials. Examples of dyes include acridine dyes, anthraquinone dyes, arylmethane dyes, azo dyes, nitro dyes, nitrous dyes, phthalocyanine dyes, quinoneimine dyes, azine dyes, indophenol dyes, oxazine dyes, oxazone dyes, thiazole dyes, xanthene dyes, xanthene dyes fluorone dyes, rhodamine dyes and natural dyes such as beta-carotene, annatto, cochineal, caramel color, beetroot extract, beet pigments, riboflavin, anthocyanins, carotenoids, apocarotenal, and paprika. Also suitable are caramelizing ingredients used to darken the color. Examples of pigments include cadmium pigments: cadmium yellow, cadmium red, cadmium green, cadmium orange; carbon pigments: carbon black (including vine black, lamp black), ivory black (bone black); Chromium pigments: chrome yellow and green chrome; cobalt pigments: cobalt purple, cobalt blue, cerulean blue, aureoline (cobalt yellow); copper pigments: Azurite, Han purple, Han blue, Egyptian blue, Malachite, Paris green, Phthalocyanine Blue BN, Phthalocyanine green G, verdigris, Viridian; Iron oxide pigments: sanguine, caput mortuum, oxide red, red ocher, Venetian red, Prussian blue; clay earth pigments (iron oxides): ocher yellow, sienna, burnt sienna, natural umber, burnt umber; lead pigments: lead white, Cremnitz white, Naples yellow, red lead; Mercury pigments: Vermilion; titanium pigments: Titanium yellow, titanium beige, titanium white such as titanium dioxide, titanium black; ultramarine blue pigments: ultramarine blue, ultramarine blue shades of green; Zinc pigments: zinc white such as zinc oxide, zinc ferrite. Other examples include alizarinA, crimson, gamboge, cochineal red, Rose Madder, indigo, Indian yellow, Tyrian purple, organic quinacridone, magenta, green phthalo, blue phthalo, red pigment.

Color developers

The moisture indicator compositions of the present invention contain at least one color developer, said color developer being defined as any substance which reacting with a leuco dye can cause its color to change from a colorless to a colored state.

When the chemical mechanism that triggers the color change in the leuco dye is the opening of a lactone ring, as in the case of CVL and other molecules of similar chemical structure, color developers can react with CVL-like leuco dyes to breaking and opening the lactone ring, include for example phenols, aromatic amines, other dyes, compounds capable of forming strong hydrogen bonds, Bronsted acids such as carboxylic acids, Lewis acids, metal salts, relative mixtures. Specific developers include for example phenolic compounds that contain one or more phenolic hydroxyls, such as for example gallic acid and its esters such as propyl gallate, octyl gallate, dodecyl gallate (lauryl), butyl gallate, the gallate of exile, the gallate of decile; monohydroxy-benzoic acids and their salts and esters, and in particular 4-hydroxybenzoic acid or salicylic acid and its salts and esters, such as zinc salicylate, zinc salt of 3,5-bis acid - (alpha-methylbenzyl) salicylic, sulphosalicylic acid and its salts and esters, 3,5-di-tert-butyl-salic acid Meo and its salts and esters, benzene-diols and di- hydroxy-benzoics and their salts and esters, benzen-triols and further tri-hydroxy-benzoic acids and their salts and esters, in addition to the aforementioned gallic acid and its derivatives, etc.

Further examples of color developers, both phenolic and non-phenolic in nature, which can be used successfully in the present invention, are benzyl-4-hydroxy benzoate, 4,4'-di-hydroxy benzophenone, 2, 4-di-hydroxy benzophenone, 2,2 ', 4,4'-tetra-hydroxy benzophenone, 2,2-bis- (p-hydroxyphenyl) propane (commonly called Bisphenol A), bis- (4-hydroxyphenyl ) methane (commonly called Bisphenol F), 4-hydroxyphenyl sulfone (commonly called Bisphenol S), bis- (3-alli 1-4-hydroxyphenyl) sulfone, 4- [4 '- [(l-methylethyloxy) phenyl] sulfonyl] phenol, 4-hydroxyphenyl 4-iso-pro-oxyphenyl sulphone, 4 - [[4- (2-propen-1-yloxy) phenyl] sulfonyl] phenol, 4-hydroxy-4'-benzyloxy -di-phenyl sulfone, the ureaurethane compound identified by CAS number 321860-75-7, 4,4'-bis- (N-carbamoyl-4-methyl benzenesulfonamide) di-phenyl methane, 2,4'-bis - (hydroxyphenyl) sulfone, the 4,4 '- (l-phenylethylidene) bisphenol (commonly called Bisphenol AP), the 2,2'-bis- (4-hydroxy-3-methylphenyl) propane (commonly called Bisphenol C), methyl-bis- (4-hydroxyphenyl) acetate, 4,4'-iso-propylidene-bis- (2 -phenyl) phenol, 1,7-bis- (4-hydroxyphenylthio) -3,5-dioxyheptane, bisphenol B, p-methyl phenol, m-nitro-benzoic acid, m- amino benzoic, tannic acid, phenol-propenoic acid, 1,2,3 triazoles, thioureas, the compound PERGAFAST 201 (i.e. 4-methyl- N- [[[3 [[(4-methylphenyl) sulfonyl] oxy] phenyl] amino] carbonyl] benzenesulfonamide), the compound called Developer D-90 and also identified with CAS number 191680-83-8, acetylsalicylic acid (or aspirin) and its salts and esters, 2-carboxy-phenyl salicylate (also known as salsalate), 2,3,4-tri-hydroxy-benzophenone, 4-hydroxy-benzophenone, 2,4-di-hydroxy acetophenone, benzyl-2 , 4, -di-hydroxy-phenyl ketone, thymol, monocyclic and polycyclic aromatic carboxylic acids, such as phthalic acids or naphthalen-acetic acid, others a phenolic and polyphenolic acids, such as, for example, 4-hydroxy benzoic acid, vanillic acid, caffeic acid, gentisic acid, ferulic acid, ellagic acid, etc. and their salts and esters.

Further examples of phenolic compounds useful in the present invention are 4-tert-butyl phenol, 4-acetyl phenol, 4-tert-octyl phenol, 4,4'-secbutylidene phenol, 4-phenyl phenol, 4, 4'-di-hydroxy-di-phenyl methane, 4,4'-isopropylidene-diphenol, hydroquinone, 4,4'-cyclo-hexylidene-di-phenol, 4,4'-di-hydroxy -di-phenyl sulfide, 4,4'-thio-bis- (6-tert-butyl-3-methyl) phenol, 4,4'-di-hydroxy-di-phenyl sulfone, the monobenzyl ether of hydroquinone, 2,4,4'-trihydroxy-benzophenone, di-methyl-4-hydroxy phthalate, methyl-4-hydroxy benzoate, ethyl-4-hydroxy benzoate, propyl-4-hydroxy benzoate, sec-butyl-4-hydroxy benzoate, pentyl-4-hydroxy benzoate, phenyl-4-hydroxy benzoate, tolyl-4-hydroxy benzoate, chlorophenyl-4-hydroxy benzoate, phenyl-4-hydroxy benzoate, phenyl-4-hydroxy benzoate, chlorophenyl-4-hydroxy benzoate, phenyl-4-hydroxy benzoate hydroxy benzoate, phenethyl-4-hydroxy benzoate, p-chlorobenzyl-4-hydroxy benzoate, p-methoxy-benzyl-4-hydroxy benzoate, 1-naphthol, 2-naphthol, phenolic rosins , polymers and kings phenolic sine, and analogous phenolic compounds.

Further examples of developers usable in the present invention also include inorganic compounds such as silica or natural or synthetic silicates, such as clays, zeolites and the like, as well as inorganic and organic compounds of polyvalent metals such as oxides, halides, carbonates, sulphates, nitrates, acetates , formates, oxalates, benzoates, acetyl acetonates, stearates, salicylates, etc., of magnesium, aluminum, calcium, titanium, zinc, cadmium, nickel, cobalt, iron, manganese, vanadium, etc. such as magnesium chloride, calcium chloride, zinc chloride, zinc bromide, zinc iodide, zinc oxide, zinc stearate, zinc glycinate, zinc resin, aluminum trichloride, aluminum oxide, aluminum stearate, glycinate aluminum, aluminum acetylacetonate etc. Silica and silicates are preferred as are compounds of zinc, aluminum, and magnesium; and among the metal compounds, zinc compounds are the most preferred. In fact, it was surprisingly discovered that above all zinc compounds, such as zinc oxide or zinc salicylates (i.e. the zinc salt of salicylic acid or the zinc salts of acids derived from it), when used alone or in combination with another developer that does not contain zinc, they greatly strengthen the color to which the leuco dyes change by contact with water and by reaction with the same color developer (s).

It has also been surprisingly found that, especially when the leuco dye used is CVL or one of its structurally analogous compounds, it is preferable that the color developer or the color developers employed in the present invention do not have / do not have a solubility in water too high. For example, it should be equal to or less than 10 grams per liter of water at 20 ° C, and more preferably it should be equal to or less than 5 grams per liter of water at 20 ° C. This is useful in avoiding possible premature color changes before actual contact with a substantial amount of water in the liquid phase, for example due to possible absorption of moisture from a humid atmosphere.

In a particular variant of the present invention, in the case in which one or more ionchromic / halochromic leuco dyes are used, the color developer (s) can / can be any chemical compound or mixture of different chemical compounds, which are capable to release, by addition of water or physiological fluids containing water, those active ions which activate the leuco dye in its color change from an initial colorless state to a final colored state.

In an even more particular variant, when the aforementioned active ions are hydrogen ions, any chemical compound that has, in contact with water, a net acid or basic reaction (depending on whether the leuco dye used changes from its colorless state to its color, in an acidic or basic environment) can work as a developer. Examples of developers that can be used for those ionchromic / halochromic leuco dyes activated by hydrogen ions, which are activated by color change in an acidic environment, are typical inorganic and organic acids, such as for example (as non-limiting examples) phosphoric acid, citric acid, tartaric acid, sulfamic acid, benzenesulfonic acid, stearic acid, isostearic acid, abietic acid, acid rosins, etc .; as well as those salts which show acidic behavior in water such as aluminum sulphate and its double sulphates (alums), sodium and potassium acid sulphates, ammonium halides, etc.

For those ionchromic / halochromic leuco dyes which are activated in a basic environment, usable developers can be for example inorganic or organic compounds that have a clearly basic behavior in water, such as for example the hydroxides, carbonates and acid carbonates of alkali metals and alkaline earth, sodium and potassium stearates and oleates, sodium tetraborate, sodium triphosphate, guanidine carbonate, amines, etc.

The moisture indicator compositions of the present invention contain from about 0.1% by weight to about 50% by weight of a color developer or a mixture of color developers, preferably from about 1% by weight to about 30% by weight. .

The hot-melt adhesive matrix

The moisture indicator compositions which are used in the present invention contain a solid matrix at room temperature which is a hot melt adhesive, also known as a hot-melt adhesive. The preparation of a hot-melt adhesive typically involves melting its components together at a high temperature, typically from at least about 50 ° C to about 180 ° C, in some variant preferably from about 60 ° C to about 150 ° C, and more preferably from about 80 ° C to about 130 ° C. In order to make the matrix processable, the moisture indicator composition must be heated to a sufficiently high temperature to ensure that the molten adhesive flows easily, but not so high as to cause thermal degradation at unacceptably high rates. It is therefore appropriate to add anti-oxidants and other stabilizers, for example stabilizers against UV rays, to the moisture indicating compositions of this invention, in such a way as to slow down the degradation rate of the hot-melt adhesive matrix. The ingredients of the moisture indicator compositions of the present invention are melted and blended together at elevated temperatures, typically within the aforementioned temperature ranges; after which said compositions, in the molten state, are applied and made to adhere to the desired substrate, always keeping them at a sufficiently high temperature so as to keep them in the liquid state.

The hot-melt adhesive matrix can contain various components, such as for example typically a thermoplastic polymer or a mixture of thermoplastic polymers, melt viscosity modifiers such as plasticizers and / or waxes, tackifiers (also called tackifiers) to increase adhesion on a wide range of different substrates, surfactants and wetting agents to improve wettability and contact with fluids containing water, organic and inorganic fillers, antioxidants, stabilizers, colored compounds such as permanent pigments and dyes, perfumes, etc.

Polymers, copolymers, terpolymers and other macromolecular materials that can be used in the present invention to form the hot-melt adhesive matrix, include for example ethylene vinyl acetate copolymers (ÈVA), styrenic block copolymers such as SIS, SBS, SEBS, SIBS and the like, polyolefins such as low density polyethylene (LDPE) and high density polyethylene (HDPE), atactic polypropylene and homopolymers and copolymers of propylene, oxidized polyethylene, polybutene and poly-iso-butylene. Other possible examples of polymers usable in a hot-melt adhesive matrix according to the present invention include polymethyl methacrylate, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, polyvinylpyrrolidone and its copolymers such as copolymers vinylpyrrolidone-vinyl acetate, sulfopolyesters such as those marketed by Eastman under the AQ brand, polyvinyl ethers, polyurethanes, polyamides, block polyester copolymers, block polyether-ester copolymers, block polyether-amide copolymers, polyether-ester copolymers - block amide, polymethacrylic acid, polyacrylic acid and its salts (which are not thermoplastic but can function as fillers), ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, the completely or partially neutralized salts of ionomers such as the aforementioned ethylene acid acrylic copolymers, polyvinyl butyral, polyethylene -oxide, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polycaprolactone, polylactic acid and its copolymers for example with glycolic acid, polyglycolic acid, ethylene-vinyl acetate oxidized copolymers, ethylene copolymers - maleic anhydride, propylene-maleic anhydride copolymers, maleic styrene anhydride copolymers, polyethylene imines, polyacrylamides, polyacrylates.

Other polymers that can be used for the purpose of the present invention are also natural or derived polymeric substances, such as for example cellulose esters and ethers, such as methylcellulose, hydroxypropylcellulose, carboxymethylcellulose, as well as pectin, guar gum, karaia gum and similar natural gums, starch and starch derivatives.

When present, such polymer or mixture of polymers are typically used in the hot-melt adhesive matrix at levels that can be effective in obtaining the expected benefits, such as for example from about 5% by weight to about 85% by weight, preferably from about 10% by weight to about 75% by weight, and more preferably from about 15% by weight to about 70% by weight of the composition.

Additional components for the hot-melt adhesive matrix used in the moisture indicator compositions of the present invention may comprise melt viscosity modifiers, such as plasticizers and waxes.

Examples of usable plasticizers are paraffinic oils, naphthenic oils, liquid poly-iso-butylenes, citric acid esters, tartaric acid esters, benzoic acid esters, sucrose esters, acid stearic and isostearic acid and their esters, trimellitates, sorbitol, urea, epoxidized vegetable oils, polymerised vegetable oils, castor oil and its derivatives, phthalates, liquid polyesters, polyamides liquids, glycolates, aromatic sulfonamides, organic amides and hydroxyamides C8-C22, polyhydric alcohols and their esters, glycerol and its esters such as glyceryl benzoates or glyceryl acetates, pentaerythritol and its esters, glycols and polyglycols and their esters and ethers, polyethylene glycol-polypropylene glycol block copolymers, sorbitan esters, liquid phosphoric esters, lactic acid and its esters, esters of monocarboxylic and dicarboxy fatty acids C8-C22 which have been modified in a hydrophilic sense by insertion in the molecular chain from 1 to 40 moles of ethylene oxide and / or propylene oxide for each mole of base ester, the polyethers and their derivatives, and the resulting mixtures.

Waxes usable in the hot-melt adhesive matrix and suitable for use in the moisture indicator compositions of the present invention include, without being limited to the given examples, mineral waxes such as paraffin and microcrystalline waxes; polyethylene waxes; waxes based on polyethylene lengl icols such as those marketed under the Carbowax brand; oxidized polyethylene waxes, polymethylene waxes, bis-stearamides and other fatty amide waxes; natural and synthetic waxes such as beeswax, soy wax, carnauba wax, ozocerite, ceresin; waxes derived from both the Fischer-Tropsch and the Ziegler-Natta processes; water-soluble waxes; polyalkylene waxes.

According to a preferred variant of the present invention, the preferred plasticizers and waxes are polar compounds such as esters of citric acid, aromatic sulfonamides, esters of benzoic acid, glycols and polyglycols and their esters and ethers, alcohols polyhydric and their esters, glycerol and its esters, sorbitan esters, C8-C22 organic amides and hydroxyamides, and their mixtures.

When present, such melt viscosity modifier or blend of melt viscosity modifiers is typically used in the moisture indicator composition at levels that can be effective in obtaining the expected benefits, such as from about 1% by weight to about 85. % by weight, preferably from about 3% by weight to about 75% by weight, and more preferably from about 5% by weight to about 70% by weight in the composition.

The hot-melt adhesive matrix of the present composition may also comprise tackifiers. Suitable adhesive agents for hotmelt adhesives usable in the moisture indicator compositions of the present invention include, without being limited to such examples, rosin resins, also called rosins, and their derivatives; terpene and terpeno-modified resins such as terpeno-phenolic resins; aliphatic resins, aliphatic and aromatic cycles such as aliphatic resins C5, aromatic resins C9, and aliphatic-aromatic resins C5 / C9, hydrogenated hydrocarbon resins, acrylic and aromatic-acrylic resins, and their mixtures. In a preferred variant of the present invention, the tackifiers are rosins and rosin esters, aromatic and aliphatic-aromatic resins, terpene and terpeno-phenolic resins, acrylic and aromatic-acrylic resins, and their mixtures.

When present, such tackifier or mixture of various tackifiers is typically used in the moisture indicator composition of the present invention at levels which can be effective in obtaining the expected benefits, such as for example from about zero to about 60% by weight and preferably from about zero to about 40% by weight in the composition.

The compositions of the present invention can contain further components such as antioxidants, absorbers and stabilizers against UV rays, inorganic and organic fillers, colored compounds such as permanent pigments and dyes, perfumes, biocides and antimicrobial preservatives, antistatic agents, etc.

Additional ingredients

Additional ingredients in the moisture indicator compositions of the present invention may comprise, for example, a surfactant or a mixture of surfactants.

Surfactants which are suitable for the present invention may comprise anionic, cationic, non-ionic and amphoteric surfactants, and any combination thereof; for example ethoxylated alcohols, fatty alcohols, high molecular weight alcohols, parethoxylated surfactants, such as those marketed by Baker Hughes under the Performathox brand, alkylated alkylates such as PEG-20-stearate, alkoxylated alcohols with protection on the end group capped, the alkylated alkoxylates of glyceryl and polyglyceryl such as PEG-30 glyceryl stearate, glyceryl alkylates such as glyceryl stearate, hydrogenated and alkoxylated castor oil, alkoxylated lanolin and hydrogenated lanolin, sorbitan alkylates and sorbitan alkoxylated alkylates, surfactants derived from sugars such as alkylglycosides and sugar esters, poloxamers, polysorbates, alkyl esters of sulfo-succinic acid, di-ethyl-hexyl-sulphosuccinate sodium, surfactants of the sodium di-octyl-sulfosuccinate family, fatty ethers of 4-1-amino-ethyl-phenol-polyoxyethylene, and polyoxy esters ethylenics of fatty acids.

Other suitable surfactants can be neutral surfactants with block copolymer structure, which can be selected from polyoxymethylene-polyoxypropylene block copolymers, poly- [polyethylene oxide-block-polypropylene oxide] copolymers or ethylene glycol-propylene glycol block copolymers. Other suitable non-ionic surfactants include polyethylene lauryl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene len-oleyl-phenyl ether, polyethylene glycol monostearate, sorbitan monolaurate, sorbitan trilaurate, polyoxyethylene sorbitanoxypropylene monolate monolaurate, polyethylene glycol sorbitan monolaurate, polypropylene glycol sorbitan monolaurate, polyethylene glycol sorbitan monolaurate, sorbitan monopalmitate, sorbitan tripalmitate, polyoxyethylene sorbitan monopalmitate, polyoxypropylene sorbitan monolaurate, polyoxypropylene sorbitan monopalmitate, polyoxypropylene sorbitan monopalmate, polyoxypropylene sorbitan monopalmitane, polyoxy propylene glycol sorbitan monopalmitate monopalmitates, sorbitan monostearate, sorbitan tristearate, polyoxyethylene sorbitan monostearate, polyoxypropylene sorbitan monostearate, polyethylene glycol sorbitan monostearate, polypropylene glycol sorbitan monostearate, polyoxyethylene sorbitan monostearate rati, sorbitan monoleate, sorbitan trioleate, polyoxyethylene sorbitan monoleate, polyoxypropylene sorbitan monoleate, polyethylene glycol sorbitan monoleate, polypropylene glycol sorbitan monoleate, polyoxyethylene glycol sorbitan monoleate, polyoxyethylene sorbitan monoleate esters, polyethylene glycol sorbitan monoleate with the brands Span and Tween.

It has surprisingly been found that, when the non-ionic surfactants constitute more than 5% by weight of the moisture indicating compositions of the present invention, surfactants with values of the HLB index not too high, for example less than 20, are preferable since they concur to the formation of darker colors, in the reaction between the leuco dye (s) and the developer (s), while they also better prevent a premature formation of the color, due for example to a partial absorption of moisture from N ' air. Therefore, when the moisture indicator compositions of the present invention contain more than 5% by weight of nonionic surfactants, surfactants with an HLB value not greater than 20 are preferable; more preferably the non-ionic surfactants used herein have an HLB value not greater than 16 and more preferably not greater than 10.

When present, such surfactant or mixture of surfactants are typically used in the composition of the present invention at levels which can be effective in obtaining the expected benefits, such as for example from about 0.001% by weight to about 90% by weight of the composition, preferably from about 0.15% by weight to about 85% by weight and more preferably from about 1% by weight to about 80% by weight.

EXAMPLES

The present invention is illustrated by the following examples, which have the sole purpose of illustrating the invention and should not be considered as limiting the scope of the invention itself or the way in which it can be put into practice. Unless specific indications to the contrary, all parts and percentages given in the examples must be understood by weight.

Example 1

The following moisture indicator composition was prepared having the ingredients and dosages described below:

Ingredient% by weight of the total weight Supplier

moisture indicator composition

PVP-VA copolymer S-630 30.0 PVP-VA copolymer supplied by Ashland

Span 60 42.0 Non-ionic surfactant supplied by Croda

Carbowax 400 24.0 Polyethylene glycol supplied by Dow Chemicals

Crystal violet lactone (CVL) 1.0 Leuco dye supplied by TCI Chemicals

3,5-di-tert-butyl-acid 2.5 Color developer supplied by salicylic (TBSA) TCI Chemicals Irganox 1010 0.5 Antioxidant stabilizer supplied by BASF

The non-ionic surfactant Span 60 plus Irganox 1010 plus half of the total amount of Carbowax 400 are heated and melted inside a heated stainless steel mixer equipped with a stirrer, at a temperature of 110 ° C. When the mass is completely melted and homogeneous, the TBSA is suspended in a quarter of the total amount of Carbowax 400 and is added. Subsequently, the PVP-VA copolymer is also slowly added to the melt, until it is completely incorporated, melted and homogeneously mixed.

As a final component, the CVL, suspended in the remaining quantity of Carbowax 400, is added to the melted composition, which is further kept under stirring for about 30 minutes in order to ensure complete homogeneity.

The resulting moisture indicator composition, while still in the molten state, is spread, at a weight of about 25 g / m <2>, on a polyethylene film, for example of the type of polyethylene films used as an external protective covering in sanitary absorbent articles. The coating of the moisture indicator composition appears colorless and remains equally colorless even if subjected for 24 hours to conditions of high temperature and high humidity, for example at 40 ° C and 75% relative humidity. However, if the above moisture indicator composition is brought into contact with a drop of water in the liquid phase or human urine, it immediately changes from colorless to a dark sapphire blue color in the area that has been wetted by water or urine. .

Example 2

The same moisture indicator composition of Example 1 was re-prepared in the same way but with the modification that 1% by weight of the non-ionic surfactant Span 60 was replaced with 1% by weight of zinc oxide, which is added, with the rest of the Span 60, at the beginning of the preparation. The final moisture indicator composition appears not only markedly whiter, but moreover, when placed in contact with a drop of water or human urine, it immediately changes to a markedly darker ultramarine color. This behavior demonstrates the beneficial effect on the wet color intensity of the moisture indicator compositions of the present invention, given by the addition, within the moisture indicator composition, of compounds of polyvalent metals and in particular of zinc compounds.

Example 3

The following moisture indicator composition was prepared having the ingredients and dosages described below:

Ingredient% by weight of the total weight Supplier

moisture indicator composition

Copolymer AC 5120 40.0 Ethylene-acrylic acid copolymer supplied by Honeywell

PVP-VA copolymer S-630 13.0 PVP-VA copolymer supplied by Ashland

Performathox 420 24.0 Non-ionic surfactant supplied by Baker Hughes

Carbowax 400 16.0 Polyethylene glycol supplied by Dow Chemicals

3- (1,2-di-methyl-3-indolyl) -3- 2.0 Leuco dye supplied by TCI [4- (di-ethylamino) -2-methyl- Chemicals

phenyl] phialide (NC BLUE 3)

4-4 'di-hydroxy-benzophenone 4.5 Color developer provided by TCI Chemicals

Irganox 1010 0.5 Antioxidant stabilizer supplied by BASF

The moisture indicator composition of Example 3 is prepared in a similar way to Example 1, by initially melting, inside a heated stainless steel mixer equipped with a stirrer, at a temperature of 120 ° C, the non-ionic surfactant Performathox 420 plus Irganox 1010 and more than half the quantity of Carbowax 400. About 15 minutes after the complete melting of the above mixture, the 4-4 'di-hydroxy-benzophenone color developer is added, after having suspended it in a quarter of the total quantity of Carbowax 400. Then the two copolymers are slowly added, first the AC 5120 and then the PVP-VA, always keeping the melt in continuous mixing until it is completely homogeneous. Finally, the leuco dye NC BLUE 3 is added together with the rest of Carbowax 400.

Spread on a polyethylene film having a weight of about 25 g / m <2>, the moisture indicator composition of Example 3 appears colorless. However, when contacted with a drop of water or human urine, the wet area quickly turns to a deep turquoise blue color.

Example 4

The following moisture indicator composition was prepared having the ingredients and dosages described below:

Ingredient% by weight of the total weight Supplier

moisture indicator composition

PVP-VA copolymer S-630 30.0 PVP-VA copolymer supplied by Ashland

Span 65 38.5 Non-ionic surfactant supplied by Croda

Carbowax 400 20.0 Polyethylene glycol supplied by Dow Chemicals

Crystal violet lactone (CVL) 2.0 Leuco dye supplied by TCI Chemicals

Pergafast 201 8.5 Color developer provided by BASF

Irganox 1010 0.5 Antioxidant stabilizer supplied by BASF

Titanium Dioxide 0.5 Pigment supplied by Huntsman

The moisture indicator composition of Example 4 is prepared in a manner quite similar to those of the preceding Examples. The non-ionic surfactant Span 65 and half of the Carbowax 400 are heated and melted inside a heated stainless steel mixer equipped with a stirrer, at a temperature of 110 ° C and are mixed with Irganox 1010 and with the dioxide. titanium. After about 15 minutes of mixing, the Pergafast 201 color developer is added, after having suspended it in a quarter of the total quantity of Carbowax 400. When the melted mass has become homogeneous again, the PVP-VA copolymer is slowly added under stirring. Finally, the leuco dye CVL mixed with the remaining quantity of Carbowax 400 is added. human urine, changes to a dark ultramarine color in seconds.

Example 5

The following moisture indicator composition was prepared having the ingredients and dosages described below:

Ingredient% by weight of the total weight Supplier

moisture indicator composition

Polyox WSR N10 22.0 Polymer Polyethylene oxide polymer supplied by Dow Chemicals

Carbowax 8000 15.0 Polyethylene glycol supplied by Dow Chemicals

Carbowax 400 50.0 Polyethylene glycol supplied by Dow Chemicals

Crystal violet lactone (CVL) 2.0 Leuco dye supplied by TCI Chemicals

Dodecyl Gallate 10.0 Color developer provided by TCI Chemicals

Irganox 1010 0.6 Antioxidant stabilizer supplied by BASF

Tinuvin 770 0.2 UV stabilizer supplied by BASF Tinuvin 928 0.2 UV stabilizer supplied by BASF

All of the Carbowax 8000, half of the Carbowax 400, Irganox 1010 and the two Tinuvin stabilizers are heated and melted at 130 ° C inside a heated stainless steel mixer equipped with a stirrer. When all the melt is at a temperature of 130 ° C, the dodecyl gallate color developer is added to the mixer together with a quarter of the total quantity of Carbowax 400. After about 15 minutes of mixing, the Polyox WSR N10 polymer is slowly added and the whole is kept under stirring until the polymer has been homogeneously incorporated into the melt. As a final component, CVL is added along with the rest of the Carbowax 400. The resulting moisture indicator composition is spread on a polyethylene film at a weight of approximately 25 g / m <2> and provides a colorless coating. Such a moisture indicator composition however, when brought into contact with water or human urine, immediately changes in wet areas from colorless to a very dark ultramarine color.

Example 6

The following moisture indicator composition was prepared having the ingredients and dosages described below:

Ingredient% by weight of the total weight Supplier

moisture indicator composition

PVP-VA copolymer S-630 33.0 PVP-VA copolymer supplied by Ashland

Benzoflex 9-88 25.0 Plasticizer di-propylene glycoledi-benzoate supplied by Eastman Span 20 8.5 Non-ionic surfactant supplied by Croda

Carbowax 4000 15.0 Polyethylene glycol supplied by Dow Chemicals

Carbowax 200 10.6 Polyethylene glycol supplied by Dow Chemicals

Alpha-naphthol-phthalein 0.4 Leuco dye supplied by TCI Chemicals

Sodium Stearate 7.0 Color developer provided by Aldrich

Irganox 1010 0.5 Antioxidant stabilizer supplied by BASF

Benzoflex 9-88, Carbowax 4000, Span 20 and Irganox 1010 are heated and melted to 110 ° C inside a heated stainless steel mixer equipped with a stirrer. When the mass is homogeneously melted, the sodium stearate color developer is suspended in half of the total quantity of Carbowax 200 and added to the melt. After about 15 minutes of mixing, the PVP-VA copolymer is slowly added and mixed until homogeneously incorporated. At this point the alpha-naphthol-phthalein leuco dye is added together with the rest of the Carbowax 200 The moisture indicator composition thus obtained is spread at a weight of about 25 g / m <2> on a polyethylene film, thus giving a colorless coating. If a few drops of water or human urine are dripped onto said coating of the moisture indicator composition, the wetted area changes from colorless to a deep turquoise blue in seconds.

Example 7

The following moisture indicator composition was prepared having the ingredients and dosages described below:

Ingredient% by weight of the total weight Supplier

moisture indicator composition

PVP-VA copolymer S-630 30.0 PVP-VA copolymer supplied by Ashland

Benzoflex 9-88 22.0 Plasticizer di-propylene glycoledi-benzoate supplied by Eastman Span 40 12.0 Non-ionic surfactant supplied by Croda

Carbowax 4000 5.0 Polyethylene glycol supplied by Dow Chemicals

Carbowax 400 10.0 Polyethylene glycol supplied by Dow Chemicals

Diethylene licole 14.4 Plasticizer supplied by TCI Chemicals

Thymolphthalein 0.1 Leuco dye supplied by TCI Chemicals

Sodium Hydroxide 3.0 Color developer provided by Aldrich

Sodium Stearate 3.0 Color developer provided by Aldrich

Irganox 101 0.5 Antioxidant stabilizer supplied by BASF

Benzoflex 9-88, Carbowax 4000, Carbowax 400, Span 40 and Irganox 1010 are heated and melted to 110 ° C inside a heated stainless steel mixer equipped with a stirrer. Separately from this melt contained inside the stainless steel mixer equipped with stirrer, the first color developer, sodium hydroxide, used in the form of a 50% by weight aqueous solution, is mixed with the second color developer, sodium stearate, and with half the total amount of diethylene glycol. The latter mixture is heated to 90 ° C to evaporate the water, introduced with the 50% solution of the sodium hydroxide color developer, and is kept under stirring at this temperature for about 30 minutes, in order to be sure that all this water has completely evaporated. At this point, the dry mixture of the sodium hydroxide color developer, the sodium stearate color developer and the diethylene glycol plasticizer is added and mixed inside the stainless steel mixer equipped with a stirrer which contains the melt at 110 ° C. When the overall mixture, inside the stainless steel mixer, is completely mixed, the PVP-VA copolymer is slowly added until it is completely melted and homogeneously dispersed. At this point the leuco dye thymolphthalein, mixed with the remaining diethylene glycol, is added to the moisture indicator composition. Said moisture indicator composition is spread on a polyethylene film at a weight of about 25 g / m <2>, giving a colorless coating. However, when said coating is wetted with water or human urine, the moistened area rapidly changes from colorless to a dark ultramarine color. Example 8

The following moisture indicator composition was prepared having the ingredients and dosages described below:

Ingredient% by weight of the total weight Supplier

moisture indicator composition

PVP-VA copolymer S-630 19.0 PVP-VA copolymer supplied by Ashland

Kraton D 1113 15.0 Styreneisoprene-styrene block copolymer supplied by Kraton

Benzoflex 9-88 25.0 Propylene glycol plasticizer supplied by Eastman Diethylene glycol 19.8 Plasticizer supplied by TCI Chemicals

Forai AX 10.0 Adhesive resin supplied by Eastman

Thymolphthalein 0.2 Leuco dye supplied by TCI Chemicals

Sodium Hydroxide 3.0 Color developer provided by Aldrich

Sodium Stearate 3.0 Color developer provided by Aldrich

Span 80 3.0 Non-ionic surfactant supplied by Croda

Irganox 101 1.0 Antioxidant stabilizer supplied by BASF

Titanium Dioxide 1.0 Pigment supplied by Huntsman

Benzoflex 9-88, Forai AX, Titanium Dioxide, Span 80 and Irganox 1010 are heated and melted at 150 ° C inside a heated stainless steel mixer equipped with a stirrer. The Kraton D 1113 copolymer is slowly added to this melt and the melt is kept under stirring until the polymer is completely homogenized. At this point the temperature of the mixer with stirrer is lowered until the melt reaches the temperature of 130 ° C.

Separately from this melt contained inside the stainless steel mixer equipped with stirrer, the first color developer, sodium hydroxide, used in the form of a 50% by weight aqueous solution, is mixed with the second color developer, sodium stearate, and with half the total amount of diethylene glycol. The latter mixture is heated to 90 ° C to evaporate the water, introduced with the 50% solution of the sodium hydroxide color developer, and is kept under stirring at this temperature for about 30 minutes, in order to be sure that all this water has completely evaporated. At this point, the dry mixture of the sodium hydroxide color developer, the sodium stearate color developer and the diethylene glycol plasticizer is added and mixed inside the stainless steel mixer equipped with a stirrer which contains the melt at 130 ° C.

At this point the PVP-VA copolymer is slowly added under continuous stirring, until the mass is homogeneous. At the end the leuco dye thymolphthalein is added, mixed with the remaining diethylene glycol. The thus obtained melted moisture indicator composition is spread at a weight of about 25 g / m <2> on a polyethylene film, giving a white coating. When this white coating is wetted with water or human urine, the wet area changes from white to a dark steel blue color in about a minute.

The dimensions and values shown here are not to be construed as strictly limited to the exact numerical value indicated. On the contrary, unless otherwise specified, each of these dimensions and values is intended to mean both the indicated value and a functionally equivalent range around the aforementioned value. For example, when a dimension is for example indicated as "40 mm" it is meant to mean that that dimension is "approximately 40 mm".

While particular variants of the present invention have been illustrated and described, it is obvious to a person skilled in the art that various other changes and modifications can be made, all within the reach of a person skilled in the art, without thereby departing from the spirit and scope. protection of the present invention, which is only defined by the following claims.

Claims (37)

CLAIMS 1) Composition indicating humidity which includes: a) a matrix consisting of a hot-melt adhesive; b) at least one coloring leuco; c) at least one color developer, wherein said moisture indicator composition is not used in a baby or woman's care article. 2) Moisture indicator composition as in claim 1, wherein the leuco dyes or leuco dyes are selected from the group containing the leuco phthalide dyes, the leuco triarylmethane dyes, the leuco fluoran dyes and their combinations. 3) Moisture indicator composition as in claim 1, in which the coloring leuco is violet crystalline lactone. 4) Moisture indicator composition as in claim 1, wherein the leuco dye is 3- (1,2-di-methyl-3-indolyl) -3- [4- (di-ethylamino) -2-methylphenyl] phthalide. 5. Moisture indicating composition as in any one of claims 2 to 4, wherein the leuco dye or the mixture of leuco dyes constitutes from about 0.01% by weight to about 20% by weight of said composition. 6) Moisture indicator composition as in claim 1, wherein the color developer is any substance that can function as a Bronsted acid or Lewis acid or is an ingredient capable of forming strong hydrogen bonds. 7) Moisture indicator composition as in claim 1, wherein the color developer is selected from the group comprising gallic acid, propyl gallate, octyl gallate, dodecyl gallate, salicylic acid, sulphosalicylic acid , 3,5-di-tert-butyl salicylic acid, acetylsalicylic acid, 2-carboxy-phenyl salicylate, hydroxy-benzophenones and in particular 4-hydroxy-benzophenone or 4,4'-di- hydroxy-benzophenone, esters of hydroxy-benzoic acids and in particular benzyl-4-hydroxy-benzoate, zinc compounds such as zinc oxide, zinc chloride, zinc stearate, zinc resin, salicylate zinc, zinc 3,5-di-tert-butyl salicylate, zinc bis- (2-hydroxy-3,5-bis- (l-phenylethyl) benzoate, aluminum sulphate, double aluminum sulphates, silica and silicates, clays, and their combinations. 8) Moisture indicator composition as in 1, in which the color developer is Pergafast 201. 9. Moisture indicator composition as in any one of claims 6 to 8, wherein the color developer or the color developer blend constitutes from about 0.1% by weight to about 50% by weight of said composition, and preferably from about 1% by weight to about 30% by weight. 10) Moisture indicator composition as in any one of claims 6 to 8, wherein the color developer is a mixture of a zinc compound, such as zinc oxide or zinc salicylates, and a second developer color that does not contain zinc. 11) Moisture indicator composition as in any one of claims 6 to 8, wherein the color developer or color developer mixture has a water solubility equal to or less than 10 grams per liter of water at 20 ° C and preferably equal to or less than 5 grams per liter of water at 20 ° C. 12) Moisture indicator composition as in claim 1, wherein the hot-melt adhesive matrix comprises at least one polymer selected from polyethylene copolymers such as ethylene-vinyl acetate copolymers or ethylene-acrylic acid copolymers or ethylene-methacrylic acid copolymers, ethylene copolymers -acrylates, polypropylene copolymers, styrenic block copolymers, poly-vinylpyrrolidone and its copolymers such as polyvinylpyrrolidone-vinyl acetate copolymers, polyamides, sulfopolyesters, poly-vinyl ethers, polyurethanes, polyester block copolymers, poly ether-ester copolymers , block polyether-amide copolymers, block polyether-esteramide copolymers, polyacrylates, polyvinyl butyral, polyethylene oxide, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polycaprolactone, polylactic acid and its copolymers for example with glycolic acid, copolymers oxidized ethylene-vinyl acetate, ethylene-maleic anhydride copolymers, propylene-anhydride copolymers maleic, styrene-maleic anhydride copolymers, polyethylene imines, polyacrylamides, cellulose ethers and esters such as hydroxypropyl cellulose, natural polymers such as pectin or guar gum and similar natural gums, or such as starch and starch derivatives, polymethacrylic acid, polyacrylic acid and its salts also in cross-linked form, and their combinations. 13) Moisture indicator composition as in claim 12, wherein said polymer or mixture of polymers constitutes from about 5% by weight to about 85% by weight of said composition, preferably from about 10% by weight to about 75% by weight and more preferably from about 15% by weight to about 70% by weight. 14) Moisture indicating composition as in claim 1, wherein the hot-melt adhesive matrix further comprises at least one melt viscosity modifier. 15) Moisture indicator composition as in claim 14, wherein said melt viscosity modifier is a plasticizer or a wax selected from benzoic acid esters, phthalic acid esters, citric acid esters, tartaric acid esters, esters of sucrose, fatty acids C8-C22 and their esters such as stearic acid and isostearic acid and their esters, trimellitates, sorbitol, epoxidized vegetable oils, polymerised vegetable oils, castor oil and its derivatives, liquid polyesters, liquid polyamides, glycolates, aromatic sulfonamides, C8-C22 fatty alcohols, polyhydric alcohols and their esters, glycerol and its esters, pentaerythritol and its esters, glycols and polyglycols and their esters and ethers, ethylene glycol-glycol block copolymers propylene, sorbitan esters, C8-C22 organic amides and hydroxyamides, liquid phosphoric esters such as tri-cresyl phosphate, and their mixtures. 16) Moisture indicator composition as in claim 15, wherein said melt viscosity modifier or blend of melt viscosity modifiers constitutes from about 1% by weight to about 85% by weight of said composition, preferably from about 3% by weight weight to about 75% by weight, and more preferably from about 5% by weight to about 70% by weight. 17) Moisture indicator composition as in claim 1, wherein the hot-melt adhesive matrix further comprises at least one adhesive agent selected from rosins (rosins) and rosin esters, aromatic and aliphatic-aromatic resins, phenolic and terpeno-phenolic resins, resins acrylics and aromatic-acrylics, and their mixtures. 18) Moisture indicating composition as in claim 17, wherein said tackifier or mixture of tackifiers constitutes from about zero to about 60% by weight of said composition, preferably from about zero to about 40% by weight. 19) Moisture indicating composition as in claim 1, wherein the hot-melt adhesive matrix further comprises a surfactant or a mixture of surfactants selected from the groups comprising non-ionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and combinations thereof. 20) Moisture indicator composition as in claim 19, wherein the surfactant is a non-ionic surfactant. 21) Moisture indicator composition as in claim 20, wherein the non-ionic surfactant has an HLB value not greater than 20, preferably not greater than 16 and more preferably not greater than 10. 22) Moisture indicating composition as in any one of claims 19 to 21, wherein said surfactant or mixture of surfactants constitutes from about 0.001% by weight to about 90% by weight of said composition, preferably from about 0, 1% by weight to about 85% by weight, and more preferably from about 1% by weight to about 80% by weight. 23) Composition indicating humidity as in claim 1, wherein the leuco dye is an ionochromic or aiochromic leuco dye. 24) Moisture indicator composition as in claim 23, in which the ionochromic or aiochromic leuco dye is thymolphthalein, alpha-naphtholphthalein, 4,5,6,7-tetrabromo-phenolphthalein, 3 ', 3 ", 5', 5" -tetrabromo -phenolphthalein, phenolphthalein, ethyl-bis- (2,4-di-nitrophenyl) acetate, and combinations thereof. 25) Moisture indicator composition as in claim 23, wherein the color developer is an alkaline hydroxide or an alkaline earth hydroxide, an alkaline carbonate, an alkaline acid carbonate, an alkaline stearate, an alkaline oleate, sodium tetraborate, trisodium phosphate , an alkylamine, an amino alcohol, guanidine carbonate, and combinations thereof. 26) Moisture indicator composition as in 23, in which the color developer is phosphoric acid, citric acid, tartaric acid, sulfamic acid, benzenesulfonic acid, stearic acid, isostearic acid, aluminum sulfate, a double aluminum sulfate (alum) , an alkaline acid sulfate, an ammonium halide, and combinations thereof. 27) Moisture indicating composition as in claim 1, further comprising a permanent dye and / or a pigment. 28) Moisture indicator composition as in claim 1, which further comprises a pH indicator, which is not a leuco dye. 29) Moisture indicator composition as in claim 1, wherein the hot-melt adhesive matrix has a Ring and Ball softening point of at least 50 ° C. 30) Moisture indicator composition as in claim 19, wherein the surfactant or mixture of surfactants has a cationic charge or multiple cationic charges. 31) Moisture indicator composition as in claim 19, wherein, wherein the surfactant or mixture of surfactants has an anionic charge or multiple anionic charges. 32) Moisture indicator composition as in claim 12, wherein the polymer or mixture of polymers has multiple cationic charges or multiple anionic charges. 33) Moisture indicating composition as in claim 1, wherein said moisture indicating composition changes from a colorless, white or translucent appearance to a visible color, or vice versa. 34) An article comprising the moisture indicating composition as in claim 1, wherein said moisture indicating composition is applied on a structural component of the article and wherein said article is not a baby care or woman's care article. 35) Article as in 34, where said article is packaging. 36) Article as in 34, where said article is an absorbent mattress or sheet or operating drape for medical use or a product for covering and protecting wounds. 37) Article as in 34, where said article is an absorbent pad or sheet for food products.