MXPA99005958A - Adhesive for secure topical attachment to the skin and comfortable removal - Google Patents

Abstract

The present invention relates to topical adhesives for attachment to the skin. In particular the present invention relates to such topical adhesives which can be employed for attachment to the skin of protective articles, clothing, prosthesis, heat wraps, pads, and/or packs, cold wraps, hearing aids, protective face masks, ornamental articles, or eye wear but excluding absorbent articles. The topical adhesive provides secure attachment and is pleasing to the skin upon application, yet causes no discomfort and a low level of adhesive residues on the skin upon removal. This is achieved by selecting the chemical composition and rheologicalcharacteristics of the topical adhesives, in particular with reference to the relationship between the elastic modulus G'and the viscous modulus G"of the topical adhesive.

Description

ADHESIVE FOR TOPIC FIXATION SAFE TO THE SKIN AND REMOVAL COMFORTABLE FIELD OF THE INVENTION The present invention describes topical adhesives for attachment to the skin. In particular, the present invention describes such topical adhesives that can be used for skin attachment, particularly for adhesion of protective articles such as bandages or elbow, knee or genital protectors; garments such as brassieres, surgical gowns, or parts of clothing during adjustment with a tailor, nasal patches, prostheses such as breast or wig replacement, thermal blankets, pads and / or packs; for topical pain relief or simply to provide warmth; cold blankets, for example to provide relief for pain from bumps and to reduce inflammation, hearing aids, protective face masks; Ornamental items, such as jewelry, earrings, costumes, tattoos, goggles or other items for the eye. The topical adhesive provides secure fixation and is comfortable for the skin on application, yet causes no discomfort and a low level of adhesive residue on the skin when removed. This is achieved by selecting the chemical composition and rheological characteristics of the topical adhesives, in particular with reference to the relationship between the elastic modulus G "and the viscous modulus G" of the topical adhesive.

BACKGROUND OF THE INVENTION The general state of the art in the field of topical adhesives for fixing to the skin is developed particularly in the field of auxiliary bands, patches and bandages. However, these articles are typically applied in an emergency situation where for example a cut in the user's skin has occurred and the absorption of liquids emanating from the wound is desired. In this context aspects of performance of the absorbent article such as comfort and ease of use and application, painless removal, discretion are subordinated to criteria such as sterility, healing support, mechanical protection of the wound. Also, such absorbent articles that cover the wound are adhered mainly to the areas of the skin where prior to the application of the absorbent article body hair could be removed or where little or no hair grows. The present invention relates to topical adhesives that are particularly useful for protective articles such as bandages or protectors of elbows, knees or genitals; garments such as brassieres, surgical gowns, or parts of clothing during adjustment with a tailor; nasal patches, prostheses such as breast replacements or wigs, thermal blankets, pads and / or packs; for topical pain relief or simply to provide warmth; cold blankets, for example to provide relief for pain from bumps and to reduce inflammation, hearing aids, protective face masks; Ornamental items, such as jewelry, earrings, costumes, tattoos, goggles or other items for the eye. Such items are not used for the absorption of body fluids. For example, the attachment of a wig to the skin on the skull or elbow and knee protectors of these body surfaces that are subject to substantial bending and extension can be conveniently made by the adhesive of the present invention. Topical adhesives that are used for absorbent articles such as sanitary napkins or pantiliners have generally been disclosed by the inventorial record of United States statute H1602 or WO 96/33683. Some more details of the adhesive have been disclosed in the PCT application WO 95/16424. This document discloses sanitary articles having a topical adhesive that is applied on the side facing the wearer of a sanitary napkin along the entire periphery. The problem underlying this document is mainly the secure adhesion to the skin, but it also mentions the problems of detachment of such articles after use without causing undue pain to a user.

The disclosure of WO 95/6424 includes a detailed analysis for topical adhesives with respect to the rheological criterion. However, this document has considered little the problem of the painless removal of such articles due to the rheological criteria taught including depilatory, for example, hair removal, composition that is commercially available as STREP MIELE (TM) sold in Italy by Laboratori Vaj SpA The adhesives for topical fixation mentioned in WO 95/16424 also include the modern pressure sensitive adhesives which are used to fix sanitary napkins to undergarments. Additionally, this document only identifies the static rheological characteristics but is silent with the dynamic rheological behavior of a topical adhesive. In WO 96/13238 a model of frequency-dependent topical adhesive is disclosed. However, all the measurements reported, for example on page 9, were made at temperatures between -60 ° C and + 120 ° C at real frequencies of 0.1 to 100 rad / s. In order to obtain the necessary data at the application temperature (around 20 ° C, typical room temperature, for example storage temperature) the Williams-Landel-Ferry equation (hereinafter WLF) was used. The WLF equation is empirical and only valid within certain limits for example can not be used to extrapolate temperatures below the glass transition temperature of a polymeric adhesive, nor can the WLF be used on the basis of values obtained below the glass transition temperature. Details about the WLF equation and its applicability can be found in "Principles of Polymer Processing" by Z. Tadmor and C.G. Gogos published by John Wiley & Sons or in "Viscoelastic Properties of Polymers" by J.D. Ferry also published by John Wiley & Sons. Since this is still missing from WO 96/13238, the applicability of the disclosed data can not be estimated. European Patent Application EP-638 303 discloses the use of a topical adhesive on the side folds of sanitary napkins in order to maintain the folds in a vertical position. The Swiss publication CH-643730 discloses the use of a very long sanitary napkin having the outer edges grooved with a topical adhesive at the four corners of the outer edges in order to provide a bit of topical adhesive area external to the region. of pubic hair growth. Both requests are silent regarding the composition of the adhesive. Based on the prior art, an object of the present invention is to provide a topical adhesive for safe fixation and painless removal of the skin, combined with a reduced amount of residual adhesive remaining on the skin or on the hair after the removal of the topical adhesive composition, by articles outside the field of the absorbent article.

It is still an object of the present invention that the topical adhesive does not cause a cold sensation or some other unacceptable temperature sensation on the application without considering a temperature difference of the adhesive with respect to the temperature of the skin. In addition to the objects of the present invention, it is desirable for topical adhesives to provide additional benefits such as release / dispersion of a compound or composition that is beneficial to the skin or the body in general. In addition, topical adhesives that do not affect the natural condition of the skin are preferred, for example being respirable or transmitters of water vapor.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to topical adhesives that are particularly useful for protective articles such as bandages or protectors of elbows, knees or genitals; garments such as brassieres, surgical gowns, or parts of clothing during adjustment with a tailor; nasal patches, prostheses such as breast or wig replacement, thermal blankets, pads and / or packs; for topical pain relief or simply to provide heat; cold blankets, for example to provide relief for pain from bumps and to reduce inflammation, hearing aids, protective face masks; Ornamental items, such as jewelry, earrings, costumes, tattoos, goggles or other items for the eye. Such items are not used for the absorption of body fluids. For example fixation of a wig to the skin on the skull or of knee protectors and elbow to those surfaces of the body that are subjected to substantial extension and bending can be conveniently done by the adhesive of the present invention. The detailed analysis of the sequence of common situations that occur from the application of such items at the time of removal have shown the specific adhesive characteristics that need to be met in order to achieve the desired performance objectives, in particular, the initial secure fixation, secure fixation during use, painless removal at the end and a reduced level of adhesive residue on the skin after removal. The characteristics that have been considered in this context are the elastic module that describes the elastic behavior of the material and the viscous module that describes the viscous behavior of the adhesive material. The viscous behavior of the adhesive can be interpreted to represent an indication of the adhesive's ability to quickly fix and adhere safely. The elastic behavior can be interpreted as an indicator of the behavior of the "firmness" of the adhesive. Its value is critical for a good initial fixation. It is thought that their combination is an indicator of the force required on the removal. The relationship between the elastic and viscous modulus is considered to be an indicator in which the fraction of the removed energy will be dissipated within the adhesive and whose fraction is available to trigger the current removal. The relationship between the elastic and viscous modules also gives an indication of the internal cohesiveness of the adhesive, which in turn is related to the possible presence of adhesive residues on the skin after the removal of the topical adhesive composition removal. In order to provide topical adhesives for prolonged and safe initial fixation and easy / painless removal the relationship between elastic modulus and viscous modulus as well as its dynamic behavior is of key importance. The topical adhesive has an elastic modulus at a temperature of 37 ° C (100 ° Fahrenheit) abbreviated G "37 and a viscous modulus at a temperature of 37 ° C (100 ° Fahrenheit) of G" 37.

The difference? (G'37-G "37) between the elastic modulus G'37 at a frequency of 1 rad / sec and the viscous modulus G" 37 at a frequency of 1 rad / sec is also defined for the topical adhesive. This difference gives an indication of the behavior of the topical adhesive with respect to the level of adhesive residue left on the skin after the removal of the topical adhesive. In addition, the adhesive has a dynamic elastic behavior defined as? G'37 which is the difference between G "37 at a frequency of 100 network / sec and G'37 at a frequency of 1 rad / sec and a dynamic viscous behavior? G "37 which is the difference between G" 37 at a frequency of 100 rad / sec and G "37 at a frequency of 1 rad / sec. According to the present invention the topical adhesive satisfies the following conditions: * G'37 (1 rad / sec) is in the range of 1500 Pa to 20000 Pa, preferably from 1500 Pa to 15000 Pa, more preferably from 3000 Pa to 10000 Pa.

* G "37 (1 rad / sec) is in the range of 100 Pa to 15,000 Pa, preferably 100 to 10000 Pa, more preferably 300 Pa to 5000 Pa. * the proportion of G'37 (1 rad / sec) / G "37 (1 rad / sec) is in the range of 3 to 30 * the ratio G "37 (100 rad / sec) - G" 37 (100 rad / sec) G'37 (1 rad / sec) - G "37 (1 rad / sec) is not less than 0.5, preferably in the range from 0.7 to 3, more preferably in the range from 1 to 1.8. * whether the ratio of? G'37 / G'37 (1 rad / sec) is not greater than 1.5, preferably not greater than unity and more preferably not greater than 0.8 or "G" 37 is not greater than 10000 Pa, preferably less than 5000 Pa, more preferably less than 2000 Pa, or both. * the difference? (G'37-G "37) (1 rad / sec) is greater than or equal to 1250 Pa, preferably greater than or equal to 2500 Pa, more preferably greater than or equal to 3500 Pa.

Additional preferable conditions are: * the value of the ratio G'37 / G "37 at least for the frequency range from above from 1 rad / sec to 100 rad / sec should preferably be 3.3 or higher, more preferably 5 or higher, more preferable of 10 or above, while not exceeding about 30, preferably 20, anywhere in the frequency range. * the rheological behavior can also be related to the value of Transition Temperature Vitrea Tg. For topical adhesives according to the present invention Tg should preferably be less than -15 ° C, more preferably less than -20 ° C and most preferably less than -25 ° C.

* The rheological behavior and the acceptance of a topical adhesive can also be related to the specific thermal capacity. Preferably the specific thermal capacity of the topical adhesive is less than 4 J / g / K, more preferably less than 3 J / g / K, most preferably less than 2 J / g / K.

* The rheological behavior and acceptance of a topical adhesive can also be related to the specific thermal conductivity of the adhesive. Preferably the specific thermal conductivity is as low as possible, preferably between 1 and 0.1 W / m / K, most preferably between 0.6 and 0.1 W / m / K. However, even thinking about these ranges allows the selection of appropriate adhesives, in the case of hot or cold blankets, it is desirable to have a relatively high value of thermal conductivity to support the function of such articles. Adhesive compositions that meet the criteria above can be used as topical adhesives for the above-mentioned articles, provided that they also meet the common requirements of being safe for use on human or animal skin during use and generally after disposal of the article. . Often the criteria of hygienic appearance and the pleasant sensation to the contact are important in such a way that transparent or white adhesive compositions are preferred, which prevent a cold, unpleasant sensation in the application. The above rheological criteria and other considerations can be met by adhesive compositions wherein the compositions comprise from 45%, preferably 51%, at 99.5% of a plasticizer compound or composition that is liquid at 20 ° C, from 0.5 to 20%, preferably 5% to 15%, of a polymeric compound or composition which is soluble or swellable in the composition plasticizer or composition and with a tackifying resin in an amount in the range of 0% to 50% by weight of the composition, preferably from 0% to 600% by weight of the polymer component. The plasticizer component or composition is selected from a group consisting of water, alcohols (preferably glycerol), glycols, polyglycols, liquid polybutenes, oil or combinations of the foregoing. The polymer component or composition is preferably selected from the group consisting of thermoplastic block copolymer elastomers, block copolymers of styrenes and block copolymers of styrenes, polyacrylics, polyvinyl alcohol, natural gums or gelatins, polyethylene oxide, polyvinylpyrrolidone (PVP), polyvinyl ethers, cellulose derivatives, or combinations thereof.

DETAILED DESCRIPTION OF THE INVENTION Adhesives for topical The adhesive according to the present invention is applied directly to the skin. In a particular application the adhesive can be used on protective articles such as bandages or protectors of elbows, knees or genitals; garments such as brassieres, surgical gowns, or parts of clothing during adjustment with a tailor; nasal patches, prostheses such as breast or wig replacement, thermal blankets, pads and / or packs; for topical pain relief or simply to provide warmth; cold blankets, for example to provide relief for pain from bumps and to reduce inflammation, hearing aids, protective face masks; Ornamental items, such as jewelry, earrings, costumes, tattoos, goggles or other items for the eye. The word "skin" according to the present invention relates to the outer surface of the dermis of humans or animals. In order to provide fixation to the skin of an article in accordance with the present invention, it is necessary to provide a certain area on the side of the article facing the skin with the topical adhesive. The topical adhesive is provided with the preferred pattern on the surface facing the user of the article in a layer having a thickness or calibrator that is preferably constant. The layer may preferably be continuous or alternatively discontinuous, for example in the form of dots, spirals or strips.

Physical, Reolócricas and Adhesive Characteristics of a Topical Adhesive Even though topical adhesives are used as pressure sensitive adhesives on human mucosal tissues, hair and skin, it is understood that topical adhesive compositions alone could hardly be considered typical pressure sensitive adhesives (referred to as ASP hereinafter) on the basis of the most characteristic rheological behaviors that identify such materials. In fact, as the person skilled in the art of adhesives knows, the most characteristic property that distinguishes an ASP from other substances that can temporarily withstand things (such as water between two glass plates) is the fact that its rheological parameters and especially the Elastic Modulus G "varies greatly with the frequency of an applied stress, more particularly, G" of ASP can increase by a few orders of magnitude while the frequency of applied stress varies from the typical frequency to the frequency of typical disunion, for example 1 rad / sec to 100 rad / s as indicated below.

As a first consequence, this derives from the fact that it is inadmissible to define materials that are intended to be used as "topical adhesives" giving values of rheological parameters and especially of a G 'at a fixed frequency value. This can be misleading because in the absence of other features it will include features that have no practical value. Therefore it is necessary that the rheological characterization should be based on dynamic considerations. This not only applies to the elastic module G 'but also to the viscous module G "and therefore also for (d) = G "/ G 'It is well known that the typical ASP not only has a large variation of G" across the considered frequencies but also has an even greater variation of G "which can be closed or even converted larger than the value of G "for example tan (d) is transformed around or even greater than 1, particularly in the frequencies that are typical of disunion. Without wishing to be bound by theory this can be interpreted as meaning that a high fraction of energy applied for disunion is dissipated within the adhesive (then this is not effective in the cause of the disunity) while this fact macroscopically causes the recording of a very high level of strength of the adhesive. As indicated above, the materials useful as topical adhesives according to the present invention have rheological characteristics which are measured at a reference temperature of 37 ° C (as the human body temperature) and in a range of frequencies. It has been found that in the application of an article such as a wig with topical adhesive the adhesive contact is formed at a low frequency, whereas the disunion occurs at the speed of removal of the article. This speed is expressed as a frequency of 100 rad / sec so much that the low frequency of formation of the adhesive bond has been found to be of the order of 1 rad / s. Therefore, the frequency range to be used in accordance with the present invention is between 1 and 100 rad / s. It is believed that the adhesive bonding characteristics are more appropriately selected at the temperature of the human body. As the topical adhesive according to the present invention is used directly on the skin and the person skilled in the art is directed to select the adhesive composition to have a small specific thermal capacity (eg preferably less than 4 J / m / K) the own temperature of the topical adhesive will reach 37 ° C very fast or it will still be hd by a human before the application. In order to provide good bonding conditions; for example at a frequency of around 1 rad / sec, the absolute values of the modules should not be very high, otherwise the adhesive is very strong and not capable of intimately joining or molding to a surface to which it is expected to adhere . It is also important to have a low absolute value of G "in order to have a good cohesion which is particularly valuable when using articles that are frequently removed and reattached or replaced, while the material remains soft and capable of adhering The proportion of G'37 (1 rad / sec) on G "37 (1 rad / sec) is important to ensure that these two amounts are balanced on adhesion in the skin. At the same time, the absolute changes of G'37 must be limited within a certain range of considered frequencies. Therefore, a value of the ratio of? G'37 (for example G'37 (100 rad / sec) -G'37 (1 rad / sec)) on G'37 has to be kept small in order to maintain secure fixation of the topical adhesive without causing discomfort over time or in removal / delamination. This can also be expressed in absolute terms by keeping the? G'37 below certain values. Importantly, the ratio of [G'37 (100 rad / sec) - G "37 (100 rad / sec)] / [G'37 (1 rad / sec) - G" 37 (1 rad / sec)] it needs to be large enough to ensure that the dynamic behavior of both elastic and viscous modules are maintained in a relationship that provides secure adhesion and easy and painless removal. Additionally, when the removal phase of a topical adhesive composition for fixing articles to the skin of the wearer is particularly considered, it is commonly recognized that good conditions for the removal of topical adhesive are achieved when the adhesive can be easily removed. of the skin, and particularly of the hair that can grow on the skin where the article makes contact with the body of the wearer, without causing pain to the user, therefore without much support on the removal of the skin and hair who saw it Particularly, as is apparent to those skilled in the art, good removal also means that the topical adhesive does not leave residues on the skin or on the hair. The difference? (G'37-G "37) between the elastic moduli G'37 (1 rad / sec) and the viscous modulus G" 37 (1 rad / sec) of the topical adhesive of the present invention is relevant to the material to provide a reduced level of adhesive residue on the skin of the wearer after removing the topical adhesive. Such a difference in fact gives an indication of the behavior of the topical adhesive of the present invention as far as concerns the level of adhesive residues on the skin of the wearer after removing the topical adhesive from the wearer's skin. Without being bound by any theory, it is believed that the difference between the elastic modulus G 'and the viscous modulus G "is a direct measurement of the internal cohesion of the topical adhesive, thus increasing the difference? (G'37-G "37) / provided with other rheological conditions are satisfied increases the internal cohesion of the topical adhesive, and decreases the possibility that residues of the adhesive remain on the skin in the removal of the topical adhesive. Finally, the person skilled in the art will also recognize that the Vitrea Tg Transition Temperature of the adhesive composition, specific thermal capacity, and specific thermal conductivity are parameters that are useful to more fully define the group of useful topical adhesives. The following group of characteristics must be satisfied: * G'37 (1 rad / sec) is in the range of 1500 Pa to 20000 Pa, preferably from 1500 Pa to 15000 Pa, more preferably from 3000 Pa to 10000 Pa.

* G "37 (1 rad / sec) is in the range of 100 Pa to 15,000 Pa, preferably 100 to 10000 Pa, more preferably 300 Pa to 5000 Pa. * the ratio of G'37 (1 rad / sec) / G "37 (l rad / sec) is in the range of 3 to 30 * the proportion [G'37 (100 rad / sec) - G "37 (100 rad / sec)] / [G'37 (1 rad / sec) - G" 37 (1 rad / sec)] is not less than 0.5, preferably in the range of 0.7 to 3, more preferably in the range of 1 to 1.8. * whether the ratio of? G'37 / G'37 (1 rad / sec) is not greater than 1.5, preferably not greater than unity and more preferably not greater than 0.8 Ó? G'37 is not greater than 10000 Pa, preferably less than 5000 Pa, more preferably less than 2000 Pa, Or both . * the difference? (G'37-G "37) (1 rad / sec) is greater than or equal to 1250 Pa, preferably greater than or equal to 2500 Pa, more preferably greater than or equal to 3500 Pa.

Additional preferable conditions are: * the value of the ratio G'37 / G "37 at least for the frequency range from above of 1 rad / sec to 100 rad / sec should preferably be 3.3 or above, more preferably 5 or above, the most preferable of 10 or above, while not exceeding about 30, preferably 20, no side in the frequency range. * the rheological behavior can also be related to the value of Transition Temperature Vitrea Tg. For topical adhesives according to the present invention Tg should preferably be less than -15 ° C, more preferably less than -20 ° C and most preferable less than -25 ° C.

* The rheological behavior and the acceptance of a topical adhesive can also be related to the specific thermal capacity. Preferably the specific thermal capacity of the topical adhesive is less than 4 J / g / K, more preferably less than 3 J / g / K, most preferably less than 2 J / g / K.

* The rheological behavior and acceptance of a topical adhesive can also be related to the specific thermal conductivity of the adhesive. Preferably the specific thermal conductivity is as low as possible, (except for articles that transmit energy where high values are more desired), more preferable between 1 and 0.1 W / m / K, most preferable between 0.6 and 0.1 W / m / K.

Chemical and composition characteristics of a Topical adhesive In order to provide topical adhesive compositions that satisfy the requirements of the physical and rheological characteristics of a topical adhesive, the following formulation criteria can be used additionally. It should be noted that most of the compositions useful as topical adhesives have a structure similar to a gel and are preferably gels. This derives from the fact that: the predominant material is the plasticizer, which is a liquid material at room temperature; a polymeric or macromolecular component is present in smaller quantities before the plasticizer. This forms, in the preferred embodiments, a three-dimensional network caused by chemical or physical bonds between the molecules. Particularly useful physical links are those present in systems containing Thermoplastic Block Elastomers. More specifically, the composition typically comprises: from 0.5 to 20%, preferably from 5% to 15%, by weight of a macromolecular polymeric substance or a mixture of such soluble or swellable substances in the aforesaid plasticizer (s). down. As non-limiting examples such polymeric or macromolecular substances can be natural and / or synthetic such as natural gums or derivatives such as gelatins and natural gums, their derivatives and alginates; polyacrylates; polyvinyl alcohol; polyethylene oxide; polyvinyl-pyrrolidone (PVP) or polyvinyl ethers, suscopolymers and derivatives thereof; cellulose derivatives; Thermoplastic Elastomers Block Copolymers and preferably Styrenic Block Copolymers and more preferably Styrene / Ethylene-Butylene / Styrene (EEBE), Styrene / Isoprene / Styrene (EIE), and Styrene / Styrene-Propylene / Styrene (EEPE) of hydrogenated grades. from 45 to 99.5% by weight, preferably 51 to 99.5% by weight, of a plasticizing substance or a mixture of plasticizing substances, which are liquids at room temperature. As non-limiting examples the plasticizer may be water, various alcohols (such as in particular glycerol), glycols and their ethers, polyglycols, liquid polybutenes, esters such as phthalates, adipates, palmitates, sebacates, or myristates, natural or synthetic oils such as oils Vegetables, mineral oils, or combinations of the above. from 0% to 50% by weight of the composition, preferably from 0% to 600% by weight of macromolecular polymeric substances of a resin that modifies the tackiness whose main subject is to adjust the Tg especially in systems based on synthetic polymers. from 0 to 10% and more preferably from 0 to 5% by weight of substances to facilitate and stabilize the gel and the gel formation process both of hydrophobic or hydrophilic liquid plasticizers. This can be for oily systems, for example the fatty acids of C8 to C22, its metal salts and its polyoxo derivatives; lanolin derivatives; silica; bentonite; montmorillonite and its derivatives; polyamides, waxes or mixtures of the above. Common additives known in the art as preservatives, antioxidants, anti UV, pigments, mineral fillers, rheology modifiers, etc., may also be comprised in amounts of above 10% each. When chemical crosslinks are formed in the system, a crosslinking agent may be present in amounts preferably above 5% by weight. Chemical cross-links may also be formed by neutralization of polymers having different functionalities such as the reaction between polyacrylic acids and polysaccharides. The resulting compositions for topical adhesives can be divided into three families according to the nature of the main component, for example, normally the liquid plasticizer (s): 1) Hydrophobic compositions in which the plasticizer is typically in an oil or mixture of oils of vegetable or mineral origin and the polymer is usually a synthetic polymer, preferably an elastomer, soluble or swellable in oil (s). 2) mixed phase compositions in which both hydrophobic and hydrophilic components, possibly in both plasticizers and polymers, form two or more separate phases. In such cases an emulsifier / surfactant is preferably present at a convenient level to form stable emulsions between incompatible phases. For topical adhesives according to the present invention it is preferable that the hydrophobic components are the predominant ones before the hydrophilic ones. 3) the hydrophilic compositions in which the plasticizer is typically water / glycerol / glycols and the like and / or mixtures thereof and the polymer phase is of natural origin (eg natural gums) or synthetic (eg polyacrylics) or mixtures of the previous ones.

It is to emphasize that, differently from the medical field and from the cited state of the art, the hydrophilic compositions are not preferred insofar as the hydrophobic and mixed phase compositions 1) and 2) are preferred in the application of the present invention. This partly depends on the technical reasons in the sense that various hydrophilic compositions used in the medical field show very low elasticity and cohesion to be useful in the present application. Additionally hydrophilic topical adhesives also tend to be perceived as cold and damp on application to a human's skin not in line with typical expectation. Additional problems result from the fact that in particular topical adhesives comprising water as the plasticizer has a tendency to dry unless sealed within an impermeable package.

Application of topical adhesive The articles with the topical adhesive according to the present invention can be used, they can be made by any of the usual means of the art. The application of the adhesive to the skin-facing surface of such an article should not cause greater problems for those skilled in the art because they can be provided by any well-known technique commonly used for other adhesives. The total area of the skin or surface facing the user of an article that is covered by the topical adhesive depends on the proposed use of the article. For the preservation of the adhesive it should not be more than 80%, preferably 30% to 60% of the surface facing the user of the article. Preferably, the adhesive extends near the periphery of the article but because it is not intended for absorbent articles it can also cover the central area of the articles. Most preferably, the adhesive is provided in a pattern of small increment areas such as dots or the like. The topical adhesive is applied on at least part of the surface facing the user of the article in a layer having a thickness or calibrator which is preferably constant, or which alternatively may vary on the surface concerned for the application of the topical adhesive. If possible, the articles provide breathability by being at least permeable to water vapor, preferably permeable to air to prevent poor ventilation. The breathability, if not supported by the topical adhesive as such, may be limited by the area of the article where the adhesive is not applied. The topical adhesive for an article is preferably protected before use. This protection can be provided by a release liner in such a way that a paper treated with surfactant or silicone agent provides easy release for the selected topical adhesive. In order to evaluate the effect of the difference? (G'37-G "37) of the topical adhesives of the present invention on the amount of adhesive residues remaining on the skin in the removal of the topical adhesive has been developed a Test of Residue In this test the adhesion of a standard substrate, provided with a layer of topical adhesives that characterizes a given value of? (G'37-G "37), is reached on the skin of the wearer's forearm, and after the successful removal of the amount of adhesive residue that remain on the skin is evaluated.

Waste Test The Residue Test is used to evaluate the amount of residues of adhesives that remain on the skin of who wears it after the removal of a sample provided with a layer of a topical adhesive and previously fixed to the forearm skin of the wearer . The test specifically evaluates the amount of adhesive residues as the residual stickiness of the skin caused by the adhesive residues, in terms of the tensile force peak (N) needed to separate a standard steel plate adhered to the skin after the Removal of the sample with the topical adhesive.

Preparation of the sample. The sample is presented in rectangular samples of 50X20 mm made of a 20μm thick polyester film, as sold by Effegidi S.p.A. of Colorono (Parma, Italy), provided on one side with a continuous layer of selected topical adhesive having a constant thickness of 1. 35 mm, applied with an Acumeter Model LH-1 extruder. A release paper is applied to protect a layer of adhesive. The samples are prepared individually and tested after one hour of preparation.

Apparatus 1) Climate controlled laboratory. Maintained at 23 ° C and 50% Relative Humidity. 2) Model 6021 Dynamometer, Instron Limited, GB. Cell load = 10 N Test speed = 1000 mm / min 3) Weight Cylindrical weight of 1 kg, 44 mm in diameter and 82 mm in height. 4) Cardboard plate. Square cardboard plate 60X60 mm.

) Steel plate Rectangular steel plate of 50X60 mm with a flat, smooth surface, and provided with means for connection of a removable fastener to the dynamometer.

Measurement of the waste. No special treatment of the user's skin is required beyond cleaning / washing with soap and water and drying at least two hours before the test so that the skin reaches equilibrium with the environmental conditions. It is selected on the inside of the skin of the forearm of the wearer a rectangular area about 10 mm long and wider than the dimensions of the sample, for example by drawing it on the skin with convenient means, said area being centered between the wrist and elbow with the long side of the area aligned with the length of the arm. Then, the sample is applied to the skin by an operator, being centered with respect to the selected area previously defined, and a pressure is exerted on it by placing the weight on the sample with the hand and leaving it there for 30 seconds, with the plate cardboard interposed between the weight and the sample in order to cover the entire surface of the sample. After removing the weight and the cardboard plate the sample is dressed by the one who wears it for an hour, and then the sample with the topical adhesive is removed from the forearm skin of the person wearing it by the operator with a soft pull and Slowly, without touching the skin where the sample was applied. The steel plate is connected to the upper moving holder of the dynamometer in such a way that its flat surface is placed horizontally, perpendicular to the direction of movement of the fastener, facing downwards. The wearer positions his arm horizontally on a convenient support on the mobile holder of the dynamometer with the selected area of the skin where the sample had been applied positioned directly below the steel plate. The forearm of the wearer and the steel plate on the bra are mutually positioned and oriented in such a way that the steel plate is centered with respect to the selected area on the forearm, with the longest dimension of the steel plate and the selected area being parallel, and with the surface of the steel plate and forearm skin in the selected area approximately parallel to each other. The Instron is operated to move the fastener with the steel plate towards the selected area until it allows the contact between the flat surface of the steel plate and the skin and apply a compression force of 9.8 N for 30 seconds., then the clamp relaxes and is recorded as a measure of the amount of residue the tensile force peak measured in Néwtones (N) needed to separate the steel plate from the selected area. The measurements are presented and averaged on five samples of the same type to ensure that the representative residue value is determined by the sample under investigation. The amount of adhesive residue left on the skin after removing the topical adhesive has been evaluated by two different samples A and B provided with two different topical adhesive compositions according to the present invention.

Sample A and sample B are provided with a topical adhesive layer according to composition 1 and composition 2, respectively, as described below.

Composition 1 An oil-based composition of the present invention was prepared using 9.9% by weight of G-1651 Kratone, a block copolymer. Styrene / Ethylene-Butylene / Styrene containing 33% styrene percent and available from Shell Co ., and 59.3% by weight of Kaydol, a paraffinic mineral oil available from Witco Co. Moreover, the composition contained 301 parts of resin that modifies tack by 100 parts of Kraton polymer. The tackifying resin was Escorez 5300, a hydrogenated resin available from Exxon Co. Magnesium Stearate, available from Cario Erba S.p.A. it was used as cogelling agent for oil at a level of 0.7% by weight. Irganox 1010, an antioxidant available from Ciba-Geigy, was added at a level of 0.3% by weight. Then, finally the composition has the following percentage composition: Kraton G-1651 9.9% by weight Kaydol 59.3% by weight Escorez 5300 29.8% by weight Magnesium stearate 0.7% by weight Irganox 1010 0.3% by weight The composition showed the following rheological properties at 37 ° C. A) Elastic modulus at 1 rad / s, G'37 = 6876 Pa B) Viscous module at 1 rad / s, G "37 = 550.5 Pa C) Viscoso and Elastic modulus at 1 rad / s, G'37 / G "37 = 12.49 D) Proportion of [G '37 (100 rad / sec) - G" 37 (100 rad / sec)] / [G' 37 (1 rad / sec) - G "37 (1 rad / sec )] = 1. 22 E) The ratio of? G'37 over G'37 (1 rad / sec) was 0. 308, with ? G'37 = 2124 Pa Composition 2 The topical adhesive is an oil-based composition containing 10% by weight of G-1651 Kratone, a Styrene / Ethylene-Butylene / Styrene block copolymer available from Shell Co., 49% by weight of Kaydol, a mineral oil paraffinic available from Witco Co. , 40% by weight of Escorez 5300, a hydrogenated tackifier resin available from Exxon Co., 0.7% by weight of Magnesium Stearate, a cogelling agent for oil available from Carlo-Erba SpA, and 0.3% by weight of Irganox 1010, an antioxidant available from Ciba-Geigy. Then, finally the formulation has the following percentage composition: Kraton G-1651 10.0% by weight Kaydol 49.0% by weight Escorez 5300 40.0% by weight Magnesium stearate 0.7% by weight Irganox 1010 0.3% by weight The composition has the following rheological properties at 37 ° C. A) Elastic modulus at 1 rad / s, 7038 Pa B) Viscous module at 1 rad / s, G "37 = 487 Pa C) Viscoso and Elastic modulus at 1 rad / s, G'37 / G" 37 = 14.45 D) Proportion of [G'37 (100 rad / sec) - G "37 (100 rad / sec)] / [G'37 (1 rad / sec) - G" 37 (1 rad / sec)] = 1.11 E) The ratio of? G'37 over G'37 (1 rad / sec) was 0.291, with ? G'37 = 2051 Pa The results of the test are summarized in the following table: The results show that the values that increase the difference? (G'37-G "37) correspond to lower amounts of adhesive residues left on the user's skin after removing the topical adhesive compositions according to the present invention. Moreover, the topical adhesive compositions described above according to the present invention have been judged as comfortable for initial application and for removal from the scalp, sensitive, without causing pain.

Claims (7)

1. A topical adhesive, for fixing to the skin, of protective articles, clothing, prostheses, thermal blankets, pads, and / or packs, cold blankets, hearing aids, protective face masks, ornamental articles or articles for the eye, but excluding absorbent articles disposable items such as wound dressings, sanitary napkins, pantiliners, incontinence articles or pads for underarm perspiration; said adhesives have an elastic modulus at a temperature of 37 ° C (100 ° F), G'37, a viscous modulus at a temperature of 37 ° C (100 ° F), G "37, and a difference? (G ') 37- G "37) between said elastic modulus G'37 (1 rad / sec) and said viscous modulus G" 37 (1 rad / sec), said adhesive being selected to have: * G'37 (1 rad / sec) is in the range of 1500 Pa to 20000 Pa, preferably from 1500 Pa to 15000 Pa, more preferably from 3000 Pa to 10000 Pa; * G "37 (1 rad / sec) in the range from 100 Pa to 15000 Pa, preferably from 100 to 10000 Pa, more preferably from 300 Pa to 5000 Pa; * the proportion of G'37 (1 rad / sec), G "37 (l rad / sec) is in the range of 3 to 30; * the proportion [G'37 (100 rad / sec) - G" 37 ( 100 rad / sec)] / [G'37 (1 rad / sec) - G "37 (1 rad / sec)] is not less than 0.5, preferably in the range of 0.7 to 3, more preferably in the range of 1 to 1.8; * alternatively, either -G'37 (100 rad / sec) - G'37 (1 rad / sec) is not greater than 10000 Pa, preferably less than 5000 Pa, preferably less than 2000 Pa; [G'37 (100 rad / sec) - G'37 (1 rad / sec)] / G'37 (1 rad / sec) is not greater than 1.5, preferably not greater than 1, most preferably not greater than 0.8 , Or a combination of the above, * the difference? (G'37-G "37) (1 rad / sec) is greater than or equal to 1250 Pa, preferably greater than or equal to 2500 Pa, more preferably greater than or equal to 3500 Pa.

2. A topical adhesive according to any preceding claim, characterized in that said adhesive is provided with a continuous layer

3. A topical adhesive according to any of the preceding claims comprising - from 45% to 99.5%, preferably 51% to 99.5 %, by weight of a plasticizer composition or component that is liquid at 20 ° C - 0.5% to 20% by weight of a composition or polymeric compound that is soluble or swellable in said composition or plasticizer compound; the tack in an amount of 0% to 600% by weight of said composition or polymeric compound

4. A topical adhesive according to claim 3 wherein said plasticizer composition or compound is selected from the following group: water, alcohols, glycogen oils, or combinations of the above; and said composition or polymeric compound is selected from the following group: thermoplastic elastomers of block copolymers, block copolymers of styrenes and block copolymers of hydrogenated styrenes.

5. A topical adhesive according to any of the preceding claims wherein 80% by weight of said adhesive consists of hydrophobic components and more preferably all components of said adhesive are hydrophobic.

6. An item such as a protective article, clothing, prosthetics, thermal blankets, pads, and / or packs, cold blankets, hearing aids, protective face masks, ornamental articles or articles for the eye, but excluding disposable absorbent articles such as dressings for wounds, sanitary napkins, pantiliners, incontinence articles or underarm perspiration pads, for adhesive attachment to the wearer's skin, said articles have a surface facing the user and a surface facing the clothing, said article comprises to the hands part of said surface facing the user a topical adhesive in accordance with claim 1 for said topical adhesive fixing of said article.

7. The use of a topical adhesive according to claim 1 on protective articles, clothing, prosthetics, thermal blankets, pads, and / or packs, cold blankets, hearing aids, protective face masks, ornamental articles, articles for viewing or cosmetics