MXPA99005951A - 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 articles such as protective articles, clothing, prothesis, heat wraps, pads, and/or packs, e.g. for topical relief of pain or simply to provide warmth;cold wraps, hearing aids, protective face masks, ornamental articles or eye wear, but excluding absorbent articles, or also of functional articles such as cosmetic or pharmaceutical delivery articles that provide a substance to the skin, decorative cosmetics or cleaning articles. The topical adhesive provides secure attachment and is pleasing to the skin upon application, yet causes no discomfort upon removal. This is achieved by selecting the characteristics of the topical adhesives, particularly the viscous modulus G"in combination with the thickness C of the topical adhesive layer in which the adhesive is provided for attachment to the skin.

Description

ADHESIVE FOR SKIN-RELEVANT TOPIC AND COMFORTABLE REMOVAL FIELD OF THE INVENTION The present invention relates to topical adhesives for bonding to the skin, said adhesive being provided as a layer. In particular, the present invention relates to topical adhesives, which can be used to bind to the skin, particularly for the adhesion of protective articles such as protectors or genital bandages, for knees or elbows; garments such as brassieres, surgical gloves, or parts of garments during fastening with a tailor; nasal plasters; prostheses such as breast replacements or wigs; thermal wrappings, pads, and / or packaging, for example, for topical pain relief or simply to provide heat; cold wraps, for example, to provide pain relief from contusions and to reduce swelling; healing aids; protective face masks; ornamental items such as jewelry, earrings, costumes, tatos; flexible eyeglasses or other items of use for the eyes. In addition, the topical adhesive can be used for the application of functional articles to the skin, particularly for the adhesion of functional articles or the improvement of the function of said articles. Functional articles in this context are cosmetic or pharmaceutical delivery articles, which provide a substance to the skin such as skin treatment substances, creams, lotions, hormones, vitamins, deodorants or drugs; alternatively pharmaceutical or cosmetic supply articles may also provide a substance for emanating from the skin such as insecticides, inhalation drugs or perfumes; the adhesive of the present invention can also be used in functional articles, which do not bind to the skin, but are a component in items that require a long residence time such as decorative cosmetics (lipstick! eyes, makeup) or cleaning items (hand cleaner, face masks, hygienic cleaners, especially for pores). The topical adhesive provides secure attachment or increased residence time and is pleasant to the skin after application, yet does not cause discomfort after removal. This is achieved by selecting the characteristics of the topical adhesives, particularly the viscous modulus G "of the topical adhesive and the thickness C of the topical adhesive layer applied to the article.

BACKGROUND OF THE INVENTION The general prior art in the field of topical adhesives for bonding to the skin is particularly developed in the field of bandage auxiliaries, plasters and bandages. These articles, however, are typically applied in an emergency situation, where, for example, a cut in the user's skin has occurred and the absorption of body fluids emanating from a wound is desired. In this context, the operating aspects of the absorbent article such as comfort and ease of use and application, pain removal, discrete characteristic are subordinated to criteria such as sterility, healing support, mechanical protection of the wound. Also said absorbent articles for covering wounds are commonly adhered to areas of the skin, where before the application of the absorbent article, e! Body hair should be removed or where little or no body hair develops. The present invention relates to topical adhesives, which are particularly useful for protective articles, such as protectors or genital bandages, for knees or elbows; garments such as brassieres, surgical gloves, or parts of garments during fastening with a tailor; nasal plasters; prostheses such as breast replacements or wigs; thermal wrappings, pads, and / or packaging, for example, for topical pain relief or simply to provide heat; cold wraps, for example, to provide pain relief from contusions and to reduce swelling; healing aids; protective face masks; ornamental items such as jewelry, earrings, costumes, tatos; flexible eyeglasses or other items of use for the eyes. These items are not used for the absorption of body fluids. For example, the attachment of a wig to the skin on the skull or of protectors for elbows and knees to these body surfaces, which undergo substantial wrinkling and extension, can conveniently be done through the combination of the present invention of a substrate. with a topical adhesive. The present invention also relates to topical adhesives, which with particularly useful for functional articles such as cosmetic or pharmaceutical supply articles also provide a substance to the skin such as treatment substances, creams, lotions, hormones, vitamins, deodorants or pharmaceuticals.; alternatively pharmaceutical or cosmetic supply articles may also provide a substance for emanating from the skin such as insecticides, inhalation drugs or perfumes; in addition the adhesive of the present invention can also be used in functional articles, which do not bind to the skin, but are a component in articles that require a long residence time such as decorative cosmetics (lipstick, colors for eyes, makeup) or cleaning items (hand cleaner, face masks, hygienic cleaners, especially for pores). These items are not used for the absorption of body fluids. For example, the attachment of a vitamin poultice to the skin or a drug release article by inhalation to the breast can conveniently be done through the topical adhesive of the present invention. The inclusion of the adhesive to decorative cosmetics allows to increase its resistance to wear, while not creating a problem of removal. Topical adhesives that are used for absorbent articles, such as sanitary napkins and pantiliners, have generally been described in the statutory inventions register of E.U.A. H1602 or WO 96/33683. Some details of the adhesive have been described in the PCT application WO 95/16424. In this document sanitary articles are described that have a topical adhesive, which is applied on the side that looks at! user of a sanitary napkin along the entire periphery. The problem that this document emphasizes is mainly the security of attachment to the skin, but also mentions problems of separation of said articles after use without causing undue pain to the user. The disclosure of WO 95/16424 includes a detailed analysis of the criteria for the topical adhesive with respect to rheological criteria. However, this document has little attention to the problem of painless removal of such articles, since the rheological criteria taught include depilation compositions, ie, hair removal, which are commercially available such as STREP MIELE (TM) sold in Italy by Laboratori Vaj SpA The adhesives for topical bonding mentioned in WO 95/16424 also include current pressure sensitive adhesives, which are used to bond sanitary napkins to underwear. Furthermore, this document only identifies the static rheological characteristics, but does not mention the dynamic rheological behavior of a topical adhesive. In WO 96/13238 a model of frequency-dependent topical adhesive is described. However, all measurements described, for example, on page 9, were made at temperatures between -60 ° C and + 120 ° C and at real frequencies of 0.1 to 100 rad / s. In order to obtain the necessary data at the application temperature (approximately 20 ° C, typical bathing environment, ie, storage temperature), the Williams-Landel-Ferry equation (hereafter WLF) was used. This WLF equation is empirical and only valid within certain limits, for example it can not be used to extrapolate at temperatures below the glass transition temperature of a polymeric adhesive, neither can WLF be used based on the values obtained below the glass transition temperature. Details regarding the WLF equation and its applicability can be found in "Principies of Polymer Processing" by Z. Tadmor and C. G. Gogos, published by John Wiley & amp; amp;; Sons in "Viscoelastic Properties of Polymers" by J. D. Ferry also published by John Wiley & Sons. Since this is lacking in WO 96/13238, the applicability of the described data can not be determined. European patent application EP-638 303 describes the use of a topical adhesive on the side folds of sanitary napkins in order to keep the folds in a straight position. Swiss publication CH-643730 describes the use of a very long sanitary napkin having external edges chamfered with a topical adhesive at the four corners of the outer edges in order to provide an area of topical adhesive outside of the hair growth region pubic. Both requests do not mention the adhesive composition. Based on the prior art, it is an object of the present invention to provide a topical adhesive to ensure the union and painless removal of the skin from articles that are outside the field of absorbent articles and / or functional articles. It is another object of the present invention to ensure, after removal, that no residual adhesive remains on the skin or on the hair or hair. It is a further object of the present invention that the topical adhesive does not cause a cold or otherwise unacceptable temperature sensation after application despite the temperature difference of the adhesive with respect to skin temperature. In addition to the above objects of the present invention, it is also desirable for topical adhesives to provide additional benefits such as delivery / dispersion of a compound or composition, which is beneficial to the skin or to the body in general. In addition, topical adhesives that do not affect the natural condition of the skin, for example, that are breathable or transmit water vapor, are preferred.

BRIEF DESCRIPTION OF THE INVENTION The present invention is useful for attachment to the skin or for wearing protective articles such as protective or bandages for genitals, knees or elbows; garments such as brassieres, surgical gloves, or parts of garments during fastening with a tailor; nasal plasters; prostheses such as breast replacements or wigs; thermal wrappings, pads, and / or packaging, for example, for topical pain relief or simply to provide heat; cold wraps, for example, to provide pain relief from contusions and to reduce swelling; healing aids; protective face masks; ornamental items such as jewelry, earrings, costumes, tatos; flexible eyeglasses or other items of use for the eyes. These items are non-absorbent for body fluids. The present invention may also be useful for attaching functional articles to the skin or improving the function of such articles when used on the skin. The functional articles are cosmetic or pharmaceutical delivery articles, which provide a substance to the skin such as skin treatment substances, creams, lotions, hormones, vitamins, deodorants or drugs; alternatively pharmaceutical or cosmetic supply articles may also provide a substance for emanating from the skin such as insecticides, inhalation drugs or perfumes; in addition, the adhesive of the present invention can also be used in functional articles, which do not bind to the skin, but are a component in articles that require a long residence time such as decorative cosmetics (lipstick, colors for eyes, makeup) or cleaning items (hand cleaner, face masks, hygienic cleaners, especially for pores). Said articles are also non-absorbent of body fluids. The topical adhesive allows the secure attachment of an article to the user's skin and supports the functionality of the articles. The term "functional" in this context means that the article that is placed on the skin satisfies an additional function, which is supported or improved by the combination according to the present invention. The articles typically have a surface that looks at the user or the body and an external surface. The topical adhesive allows the attachment of an article to the user's skin, being provided as a layer having a certain thickness or caliber C measured in millimeters (mm). The detailed analysis of the sequence of common situations that occur from the application of said articles at the time of removal has shown that the specific characteristics of adhesion preferably need to be met in order to achieve the desired performance objectives, in particular a safe initial connection, a secure joint during use and painless removal at the end. The characteristics that have been considered in this context are the elastic module that describes the elastic behavior of the material and the viscosity module, which describes the viscous behavior of the adhesive material. The viscous behavior of the adhesive can be interpreted to represent an indication of the ability of the adhesive to bond quickly and adhere safely. The elastic behavior can be interpreted as an indication of the "hardness" behavior of the adhesive. Its value is also critical for a good initial bond. -It is believed that their combination is an indicator of the force required after the removal. The relationship between the elastic and viscous modulus is considered to be an indication on which the fraction of removal energy will be dissipated within the adhesive and the fraction is available to activate the actual removal. In order to provide topical adhesives for safe, initial and prolonged bonding and easy removal without pain, the relationship between the elastic module and the viscous module, as well as its dynamic behavior, is an important key. The topical adhesive has an elastic modulus at a temperature of 37 ° C, abbreviated as G'37, a viscous modulus at a temperature of 37 ° C of G "37, and a viscous modulus at a temperature of 25 ° C of G" 25 The adhesive also has a dynamic elastic behavior defined as? H'37, which is the difference of G'37 at a frequency of 100 rad / sec., And G'37 at a frequency of 1 rad / sec., And a dynamic viscous behavior? G "37, which is the difference of G" 37 at a frequency of 100 rad / sec, and G "37 at a frequency of 1 rad / sec. The topical adhesive according to the present invention preferably satisfies the following conditions: • G'37 (1 rad / sec) is on the scale from 1500 Pa to 20000 Pa, preferably 1500 Pa to 15000 Pa, most 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 Pa to 10000 Pa, most preferably 300 Pa to 5000 Pa. • the ratio of G'37 (1 rad / sec.) / G "37 (1 rad / sec.) Is on the scale from 3 to 30. 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 on the scale of 0.7 to 3, most preferably on the scale of 1 to 1.8. ? G'37 G'37 (1 rad / sec.) Is not greater than 1.5, preferably not greater than unity and most preferably not greater than 0.8 or? G'37 is not greater than 10000 Pa, preferably lower than 5000 Pa, and most preferably less than 2000 Pa, or both.

• The value of the ratio G'37 / G "37 at least for the frequency scale of above 1 rad / sec, up to 100 rad / sec., Preferably must be 3.3 or more, most preferably from 5 or more, preferably 10 or more, while not exceeding about 30, preferably 20, at any frequency interval • The rheological behavior will also be related to Tg Glass transition temperature values. For topical adhesives according to with the present invention, the Tg preferably should be less than -15 ° C, most preferably less than -20 ° C, and preferably less than -25 ° C. • The rheological behavior and the acceptance of a topical adhesive can also be relate to the specific thermal capacity Preferably, the specific thermal capacity of the topical adhesive is less than 4 J / g / K, preferably 3 J / g / K and most preferably less than 2 J / g / K. rheology and the acceptance of a glue peak 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, although these scales allow the selection of appropriate adhesives, in the case of thermal or cold wraps, it is desirable to have a relatively high value of thermal conductivity to support the function of said articles. By providing that the above rheological conditions are satisfied, the adhesives will also satisfy conditions such as sufficient adhesion (to avoid adhesive residue on the skin), which are critical to commercial use of said adhesives and evident to those skilled in the art. Adhesive compositions that meet the above criteria can be used as topical adhesives for the aforementioned articles, provided they meet the common requirements of being safe to use on the skin of humans or animals, during use and generally after the disposal of the article. In general, the criteria of hygienic appearance and pleasant sensation after contact are important so that adhesive compositions which are transparent or white and which avoid a cold, unpleasant sensation after application are preferred. The above rheological criteria and other considerations can be satisfied through adhesive compositions, in the composition it comprises 45%, preferably 51% to 99.5% of a plasticizing compound or composition, which is liquid at 20 ° C, of 0.5 to 20%, preferably 5% to 15% of a polymeric compound or composition, which is soluble or swellable in the plasticizer composition or composition and with an adherent resin in an amount in the range of 0% to 50% in weight of the composition, preferably from 0% to 600%) by weight of the polymeric compound. The plasticizing compound or composition is preferably selected from the group consisting of water, alcohols (preferably glycerol), glycols, polyglycols, liquid polybutenes, oil or combinations thereof. The polymeric compound or composition is preferably selected from the group consisting of block copolymer thermoplastic elastomers, styrene block copolymers, and hydrogenated styrene block copolymers, polyvinyl alcohol, natural gum or gelatins, polyethylene oxide, polyvinylpyrrolidone (PVP), polyvinyl ethers, cellulose derivatives, or combinations thereof. According to the present invention, it has been found that the ratio between the thickness or gauge C, measured in millimeters (mm), of the layer in which the topical adhesive is provided, for example, at least on the part of the surface which looks at the body of the article, and the viscous modulus G "25 at about 100 rad / sec, of the topical adhesive is important for the scope of providing an easy and painless removal of the user's pile of said topical adhesive applied over at least part of the surface facing the user of an article for attachment of said article to the skin of a user The topical adhesive of the present invention provided as a layer having a thickness C is such that the viscous modulus G "25 ( 100 rad / sec.) And thickness C satisfy the following empirical equation: < [(4.26 + C) • 1605] Pa and preferably the following empirical equation: G "25 < [(1-53 + C) • 1724] Pa DETAILED DESCRIPTION OF THE INVENTION Adhesive for topical bonding The topical adhesive of the present invention is applied directly to the skin. In a particular application, the adhesive can be used on protective articles, such as "genital protectors or bandages, for knees or elbows; garments such as brassieres, surgical gloves, or parts of garments during fastening with a tailor; nasal plasters; prostheses such as breast replacements or wigs; thermal wrappings, pads, and / or packaging, for example, for topical pain relief or simply to provide heat; cold wraps, for example, to provide pain relief from contusions and to reduce swelling; healing aids; protective face masks; ornamental items such as jewelry, earrings, costumes, tatos; flexible eyeglasses or other items of use for the eyes. The topical adhesive according to the present invention can also be used in the context of functional articles such as cosmetics or pharmaceutical delivery articles, which provide a substance to the skin such as skin treatment, substances, creams, lotions, hormones. , vitamins, deodorants or drugs; alternatively pharmaceutical or cosmetic supply articles may also provide a substance for emanating from the skin such as insecticides, inhalation drugs or perfumes; in addition, the adhesive of the present invention can also be used in functional articles, which do not bind to the skin, but are a component in articles that require a long residence time such as decorative cosmetics (lipstick, colors for eyes, makeup) or cleaning items (hand cleaner, face masks, hygienic cleaners, especially for pores). The word "skin" according to the present invention refers to the outer surface of the dermis of humans or animals. In order to provide fixation of an article according to the present invention to the skin, it is generally necessary to provide a certain area on the side of the article that is facing the skin with the topical adhesive. The topical adhesive is provided with the preferred pattern, typically on the surface facing the user of the article as a layer having a thickness or gauge C that is preferably constant. The layer may preferably be continuous or alternatively discontinuous, for example, in the form of dots, spirals or strips.

Physical, Reopathic and Adhesive Characteristics of a Topical Adhesive Although topical adhesives are used as pressure sensitive adhesives on human skin and mucosal tissue, it is understood that topical adhesive compositions can hardly be considered as adhesives. typical pressure sensitive (hereafter referred to as PSA) based on most of the characteristic rheological behaviors that identify such materials. In fact, as those skilled in the art of adhesives know, the most characteristic feature that distinguishes a PSA from other substances that can temporarily stick to things (for example, water between two glass plates), is the fact that its Rheological parameters and especially Elastic Modulus G 'vary greatly with the frequency of applied stresses. More particularly, G 'of PSA can be increased by some orders of magnitude, while the frequency of applied voltages varies from typical binding frequency to typical separation frequency, i.e., 1 rad / sec, to 100 rad / sec, as is indicated later. As a first consequence, it is inferred that it is inadmissible to define materials destined to be used as "topical adhesives" giving values of rheological parameters and especially of G 'as a fixed frequency value. This can be deceptive, since in the absence of other characteristics will include materials that have no practical value, Therefore, it is necessary that the rheological characterization must be done based on dynamic considerations. This not only applies to the Elastic Module G ', but also to the viscous module G "and, therefore, also for tan (d) = G" / G'. It is well known that typical PSA does not only have a high variation of G 'through the considered frequencies but also there is an even higher variation of G ", which can approach or even become higher than the value of G', that is, so (d) becomes approximately or even greater than 1, in particular at the frequencies that are typical of the separation, without wishing that it is bound by theory, this can be interpreted as a high fraction of the applied energy so that the separation is dissipated within the adhesive (so it is not effective to cause separation), as this fact macroscopically causes the registration of a very high level of adhesive force.As indicated above, the materials useful as topical adhesives according to the present invention have rheological characteristics, which are mostly measured at a reference temperature of 37 ° C (as the usual body temperature of humans) and in a It has been found that after the application of an article, such as a wig or a vitamin poultice with a topical adhesive, contact of the adhesive is formed at a low frequency, while the separation occurs at the speed of removal of the article. This speed is expressed at a frequency of 100 rad / sec, while the low frequency of formation of the topical adhesive has been found to be of the order of 1 rad / sec. Therefore, the frequency scale to be used according to the present invention is between 1 and 100 rad / sec. It is believed that the adhesive bonding characteristics are very appropriately selected at the temperature of the human body. Since 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 so that it has a small specific thermal capacity (for example, preferably less than 4 J / g / K), the actual temperature of the topical adhesive will reach 37 ° C very quickly or will still be heated by a human before application. In order to provide good conditions, ie, at a frequency of about 1 rad / sec., The absolute values of the elastic modulus should not be too high, otherwise the adhesive will be very hard and will not be able to bind intimately or molded to the 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 articles are used that are often removed and adhered again or replaced while the material remains soft and able to adhere moderately The ratio of G'37 (1 rad / sec) to G "37 (1 rad / sec) is important to measure that these two values are balanced after adhesion to the skin. At the same time, the absolute changes of G'37 need to be limited within the scale of frequencies considered. In this way, a value for the ratio of? G'37 (ie, G'37 (100 rad / sec.) - G'37 (1 rad / sec.)) Over G'37 (1 rad / sec. ) has to be kept small in order to maintain the secure bonding of the topical adhesive without causing discomfort over time or during removal / delamination. This can also be expressed in absolute terms keeping "G'37 below certain values. Importantly, the relationship 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 the elastic and the viscous modulus are maintained in a relationship that provides a secure and painless adhesion and easy removal. Finally, the person skilled in the art will also recognize that the Glass Transition Temperature, Tg, of the adhesive composition, the specific thermal capacity, and the specific thermal conductivity are parameters, which are useful to more fully define the group of useful topical adhesives. . The following group of characteristics should preferably be satisfied for the topical adhesive of the combination of the present invention: • G'37 (1 rad / sec) is on the scale from 1500 Pa to 20000 Pa, preferably 1500 Pa to 15000 Pa, most preferably from 3000 Pa to 10000 Pa.

G "3 (1 rad / sec.) Is in the range of 100 Pa to 15000 Pa, preferably 100 Pa to 10000 Pa, most preferably 300 Pa to 5000 Pa. The ratio of G'37 (1 rad / sec. ) / G "37 (1 rad / sec.) Is on the scale from 3 to 30. G'37 (100 rad / sec.) - G" 37 (100 rad / sec.) G'37 (1 rad / sec.) - G "3 (1 rad / sec.) Is not less than 0.5, preferably on the scale of 0.7 to 3, most preferably on the scale of 1 to 1.8. of? G'37 / G'37 (1 rad / sec.) is not greater than 1.5, preferably not greater than unity, and most preferably not greater than 0.8, or? G'37 is not greater than 10000 Pa, preference less than 5000 Pa, and most preferably less than 2000 Pa, or both • The value of the ratio G'37 / G "37 at least for the frequency scale of above 1 rad / sec, up to 100 rad / sec, preferably it should be 3.3 or more, most preferably 5 or more, preferably 10 or more, while not exceeding about 30, preferably 20, in any frequency range. • The rheological behavior also be related to values of the Tg Glass Transition Temperature. For topical adhesives according to the present invention, the Tg preferably should be less than -15 ° C, most preferably less than -20 ° C, and 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, preferably 3 J / g / K and most preferably less than 2 J / g / K. • The rheological behavior and the 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 power transmission articles, where high values are more desirable), preferably between 1 and 0.1 W / m / K, most preferably between 0.6 and 0.1 W / m / K.

Chemical and Compositional Characteristics of a Topical Adhesive In order to provide topical adhesive compositions that meet the requirements of the above rheological and physical characteristics of a topical adhesive, additionally the following formulation criteria should be used. It should be noted that most of the compositions useful as a topical adhesive have a substantially gel-like structure, and are preferably gels. This is derived from the fact that: - the prevailing component is the plasticizer, which is a liquid material at room temperature; A macromolecular or polymer component is present in minor amounts against the plasticizer. It forms, in the preferred modalities, a three-dimensional network caused by the physical or chemical bonds between the molecules. Particularly useful physical links are those present in systems containing Thermoplastic Block Elastomers. More specifically, the compositions typically comprise: - from 0.5 to 20%, preferably from 5% to 15%, by weight of a macromolecular polymer substance or a mixture of said substance soluble or swelling in the plasticizer (s) ) mentioned later. Non-limiting examples such as macromolecular or polymeric substances can be natural and / or synthetic, such as natural gums or derivatives such as natural gums and gelatins, their derivatives and alginates; polyacrylics; polyvinyl alcohol; polyethylene oxide; polyvinylpyrrolidone (PVP) or polyvinyl ethers, their copolymers and derivatives; cellulose derivatives; Thermoplastic Copolymer Elastomers and preferably Synthetic Block Copolymers and most preferably the hydrogenated grades styrene / ethylene-butadiene / styrene (SEBS), styrene / isoprene / styrene (SIS), and styrene / ethylene-propylene / styrene (SEPS); from 45 to 99.5% by weight, preferably from 51 to 99.5% by weight of a plasticizer or a mixture of plasticizing substances, which are liquid at room temperature. As non-limiting examples, the plasticizer can be water, various alcohols (such as glycerol in particular), glycols and their ethers, polyglycols, liquid polybutenes, esters such as phylalates, adipates, stearates, palmitates, sebacates, or myristates, natural or synthetic oils such as vegetable oils, mineral oils or combinations thereof; from 0% to 50% by weight of the composition, preferably from 0 to 600% by weight of the macromolecular polymer substance of an adherent resin whose main scope is to develop the Tg especially in systems based on synthetic polymers; from 0 to 10% or and most preferably from 0 to 5% by weight of substances to facilitate and stabilize the gel and the gel-forming process of both hydrophilic and hydrophobic liquid plasticizers. These can be oily systems, for example, the fatty acids of 8 to 22 carbon atoms, their metal salts and their polyoxie derivatives; lanolin derivatives; silica, bentonite, montmorillonite and its derivatives; polyamides, waxes or mixtures thereof. Common additives known in the art such as preservatives, antioxidants, anti-UV, pigments, mineral fillers, rheology modifiers, etc., may also be comprised in amounts of up to 10%, each. When chemical entanglements are formed in the system, preferably an entanglement agent may be present in amounts of up to 5% by weight. Chemical entanglement can also be formed through mutual neutralization of polymers having different functionalities as in the reaction between polyacrylics and acidic polysaccharides. The resulting compositions for the topical adhesives can be divided into three families according to the nature of the main component, i.e., usually the liquid plasticizer (s): 1) Hydrophobic compositions wherein the plasticizer is typically an oil or a mixture of oils plant or mineral origin and the polymer is usually a synthetic polymer, preferably an elastomer, soluble or swellable in oil (s). 2) Mixed phase compositions wherein both hydrophobic and hydrophilic components, possibly in both plasticizers and polymers, form two or more separate phases. In such cases, preferably an emulsifier / surfactant is present at a suitable level to form stable emulsions between the incompatible phases. For the topical adhesives according to the present invention, it is preferable that the hydrophobic components are predominant vs. the hydrophilic. 3) Hydrophilic compositions wherein typically the plasticizer is water / glycerol / glycols and the like and / or mixtures thereof and the polymer phase is of synthetic (eg, polyacrylic) or natural (eg, natural gums) or mixtures of the same. It should be emphasized that, unlike the medical field and the prior art cited, hydrophilic compositions are not preferred, since the hydrophobic and mixed phase compositions, 1) and 2), are preferred in the applications of the present invention. This partly depends on technical reasons, in the sense that many hydrophilic compositions used in the medical field show a very low elasticity and cohesion to be useful in the present application. For example, for most functional items, mixed phase compositions are preferred. For functional articles with a supply function, the compound that will be supplied needs to leave the topical adhesive composition at different rates, for example, the perfumes may have a supply profile, which changes from high to low values, while the Drugs have to be supplied preferably at a constant rate to prevent overdose. Cosmetics are generally lipophilic and moisturizing, so a combination of aqueous and oily components is very desirable. In addition, hydrophilic topical adhesives also tend to be perceived as cold and wet, which after application to the skin of a human being does not agree with the typical expectation. Additional problems arise from the fact that in particular topical adhesives comprising water as the plasticizer, they tend to dry rather than being sealed to a waterproof package.

Topical Adhesive Application Articles, comprising functional articles as previously defined, wherein the topical adhesive according to the present invention can be used by being provided as a layer having a thickness or caliper C measured in millimeters (mm), can be done through any of the usual techniques. The functional article in this context also defines whether the adhesive is provided to maintain a substrate on the skin or whether the adhesive as part of a composition is provided directly to the skin. In the first case, the application of the adhesive to the surface facing the skin of said articles should not cause major problems for those skilled in the art, since it can be provided by any of the commonly known techniques used for other adhesives. . In this context, the total area of the skin or surface facing the user of an article that is covered by the topical adhesive depends on the intended use of the article. For consideration of the article, this should be no more than 80%, preferably no more than 30% to 60% of the surface that the user of the article looks at. Preferably, the adhesive extends near the periphery of the article, but since it is not intended for absorbent articles, it can also cover the central area of the articles. Most preferably, the topical adhesive is provided in a pattern of small increasing areas such as dots or the like. The topical adhesive is provided, for example, on at least part of the surface facing the user of the article, such as a layer having a thickness or caliper C which is preferably constant, or which may alternatively vary on the surface concerned by the application of the topical adhesive. If possible, the article also provides breathability by being at least permeable to water vapor, preferably permeable to air to prevent poor ventilation. The ability to breath, if not supported by the topical adhesive as such, may be limited to the area of the article where no adhesive is applied. The topical adhesive on an article is preferably protected before use. This protection can be provided through a release liner such as a paper treated with silicone or surfactant, provg an easy release for the selected topical adhesive. When the removal phase of a topical adhesive for the attachment of articles to the skin of a user is particularly considered, it is commonly recognized that good removal conditions, ie, at a frequency of approximately 100 rad / sec, of the adhesive Topical applied to at least part of the surface facing the user of an article to attach said article to the skin of a user, can be obtained when the adhesive can be easily removed from the skin, and particularly of the hair that may possibly be present on it, where the article makes contact with the body, without causing pain to the user, therefore without adhering too much after the removal to the user's skin and hairs. In addition, a good removal implies that the topical adhesive leaves no residue on the skin or hair. According to the present invention, the ratio between the thickness or gauge C measured in millimeters (mm) of the layer in which the topical adhesive is provided, for example, typically on at least part of the surface facing the user of the article, and the viscous module G "25 at 25 ° C and approximately 100 rad / sec., of the topical adhesive gives an indication of the painless and easy removal of the topical adhesive from the user's skin, without being bound by theory, it is believed that for higher values of G "25 to 100 rad / sec, which correspond to a higher adhesion of the composition, a thicker gauge or thickness of the adhesive layer is necessary so that the applied energy for the removal is more evenly distributed within the mass of the adhesive, and, therefore, it is moderately transferred to the skin, thus avoiding energy spikes that typically cause the sensation of pain to the user. In other words, less rigid combinations of substrates with topical adhesives need an adhesive with a lower G "25 at 100 rad / sec, to achieve a reduced pain sensation after the removal of the article comprising the combination. the present invention, the combination of the substrate with the topical adhesive applied thereon, said combination having a stiffness S, is such that the viscous modulus G "25 (100 rad / sec) and the thickness C of the adhesive layer satisfy the following empirical equation: G "25 < [(4.26 + S) • 1605] Pa and preferably the following empirical equation: G "25 < [(1-53 + S) • 1724] Pa Although in a preferred embodiment of the present invention, the thickness C of the adhesive layer is constant, said adhesive layer may also have different thicknesses in different portions of the surface facing the user of the article, where it is applied, provided that the ratio above mentioned between C and G "25 is in any case satisfied.In order to evaluate the effect of the thickness C of the topical adhesive layer in its relation to the viscous modulus G" 25 (100 rad / sec.) of the topical adhesive of the present invention in the removal of the topical adhesive used for the attachment of an article to a user's skin, a Removal Pain Rating Test has been developed. In this test, the adhesion of standard substrates is achieved, over which the same topical adhesive has been provided in layers having different thicknesses, on the forearm skin of members of a perception panel, and after the successive removal, the Pain is evaluated in terms of degree of pain.

Pain Rating Test for Removal The Removal Pain Rating Test is used to evaluate pain during the removal of a user's skin from a sample provided with a topical adhesive layer and previously attached to the user's skin. The test specifically assesses the pain after the removal of each sample as compared to the pain obtained by the removal of a reference sample constituted by a commercial strong medical plaster.

Sample Preparation The test was performed on rectangular samples of 60 x 20 mm made of a polyester film with a thickness of 23 μm, such as those sold by Effegidi S.p.A. of Colorno (Parma, Italy), provided on one side with a continuous layer of the topical adhesive having the selected thickness, applied with an Acumeter extruder model LH-1. The reference sample is a 60 x 20 mm sample of a double-sided medical adhesive tape produced by Minnesota Minino and Manufacturing Company under the trade name of Medical Tape No. 1524; only one of the two adhesive layers is exposed on the reference sample and used to bind to the skin during the test.

Test Method A panel of six graders was selected for the test. The test was carried out in a climatically controlled laboratory, where a temperature of 23 ° C and a relative humidity of 50% were maintained. No special treatment of the user's skin was required beyond a normal cleaning / washing with soap and water and drying for at least 2 hours before the test to achieve equilibrium with the environmental conditions for the skin. Three different tests A, B, and C were evaluated in the test compared to the reference sample R. Each sample was applied by hand through an operator to the inner part of the forearm of the grader, being centered between the wrist and the elbow, with the short side of the sample aligned with the length of the arm. The operator exerts on each sample with his palm the same pressure that is typically applied to make a medical plaster adhere to the skin. Each sample was used for the prescribed time, and then removed from the grader skin with a slow and gentle pull. Four series of a reference sample R and three samples A, B and C were applied, each one was used and then removed from the user's skin; each sample was used for one minute, with a wait of 5 minutes between two subsequent samples of the same series, and a wait of 15 minutes between two different subsequent series. The reference sample R was always applied, used and removed as the first sample of its respective series. The sequence of application / use / removal of samples A, B and C in each of the first three series is random, provided that no repetition is allowed in each series, and that no sequence is repeated in the first three series. In the fourth series of the four samples, one of the samples A, B or C was tested twice, the reference R always being the first. In summary, each sample (A, B and C) has to be tested an equal number of times (24 times according to the scheme presented below). In the tests carried out, the sequences of the four series are in accordance with the following scheme: Graders were asked to evaluate each sample A, B and C using a pain scale ranging from 0 to 10, where 0 corresponds to no pain and 10 corresponds to pain after removal of the reference sample R. The values of pain for each sample A, B and C were obtained as an average of 24 observations. The results collected from the test were analyzed through a statistical analysis program "Comparison of Population Means - Paired Samples", which showed that the differences between the pain values of samples A, B and C are statistically important. The pain after removal was evaluated according to the Removal Pain Test for three different samples A, B and C, each consisting of the same standard substrate, on which the same topical adhesive composition is provided as a layer uniform thickness predetermined. The topical adhesive is an oil-based composition containing 10% by weight of Kraton G-1651, 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 wt% magnesium stearate, a co-gelling agent for oil available from Cario Erba SpA, and 0.3 wt% Irganox 1010, an antioxidant available from Ciba-Geigy. So the formulation had the following composition in percentage: 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 / sec, G'37 = 7038 Pa b) Viscous modulus at 1 rad / sec, G "37 = 487 Pa c) Ratio of Viscous elastic modulus at 1 rad / sec: d) Ratio 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 / s) was 0.291, with the composition in addition it has a viscous modulus G "25 at 25 ° C and at approximately 100 rad / sec, of 4431 Pa. The thickness of the adhesive layers of the three samples and the respective degrees of pain are shown in the following table: The results show that for a given topical adhesive composition, represented by the value of G "25 (100 rad / sec.) Of 4431 Pa, the increasing thickness values for the topical adhesive layer correspond to reduced degrees of durometer after of the removal of the topical adhesive from the skin Of course, the thickness values for the topical adhesive layers comprised in different articles can be varied according to the empirical equations of the present invention, in order to obtain degrees of pain by acceptable removal with different topical adhesive compositions, and, therefore, with different values of G "25 (100 rad / sec), within the limits that can be easily determined by the person skilled in the art. Usually, in the field of the items defined above, this limit should not exceed 10 mm. The same is true for the possible selection of preferred topical adhesive compositions having different values of G "25 (100 rad / sec) that will be applied in a layer having a certain preferred thickness in order to reduce the degree of pain after Removal of the skin article The possible preferred limits for G "25 (100 rad / sec) of a topical adhesive composition are implicitly defined, for example, by the preferred rheological characteristics of the topical adhesive compositions.

Claims (9)

1. - A topical adhesive to be attached to the skin of articles such as protective articles, clothing, prosthetics, thermal wrappings, pads and / or packaging, cold wraps, healing aids, protective face masks, ornamental or eye wear items, or functional articles that are cosmetics or pharmaceutical supply articles, decorative cosmetics or cleaning articles, but excluding disposable absorbent articles such as wound dressings, sanitary napkins, pantiliners, incontinence articles or armpit sweat pads, said topical adhesive being provided as a layer having a thickness C measured in millimeters (mm), said adhesive having an elastic modulus at a temperature of 37 ° C, G'37, and having a viscous modulus at a temperature of 37 ° C, G "37, and a viscous modulus at a temperature of 25 ° C, G'25, said topical adhesive is characterized in that said viscous modulus G "25 (100 rad / sec .) and said thickness C satisfy the following equation: G "2 < [(4.26 + C) • 1605] Pa

2. - A topical adhesive according to claim 1, characterized in that the viscous modulus G "25 (100 rad / sec) and the thickness C satisfy the following equation: 25 <[(1.53 + C) • 1724] Pa

3. - A topical adhesive according to claims 1 or 2, characterized in that the adhesive is selected to have: • G'3 (1 rad / sec.) Is on the scale from 1500 Pa to 20000 Pa, preferably 1500 Pa to 15000 Pa, most preferably from 3000 Pa to 10000 Pa; • G "37 (1 rad / sec.) Is on the scale of 100 Pa to 15,000 Pa, preferably 100 Pa to Í0000 PaJ most preferably 300 Pa to 5000 Pa • the ratio of G'37 (1 rad / sec) .) / G "37 (1 rad / sec.) Is on the scale 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 on the scale of 0.7 to 3, most preferably on the scale of 1 to 1.8; 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, or - the ratio: 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 thereof.

4. A topical adhesive according to any of the preceding claims, characterized in that said adhesive is provided as a continuous layer.

5. A topical adhesive according to any of the preceding claims, characterized in that it comprises: - of 45% > to 99.5%, preferably from 51% to 99.5% by weight of a plasticizer compound or composition, which is liquid at 20 ° C; - from 0.5 to 20% > of a polymeric compound or composition, which is soluble or swellable in the plasticizer composition or composition; - an adherent resin in an amount of 0% > at 50% by weight, preferably from 0% to 600% > by weight of the composition or polymeric compound.

6. A topical adhesive according to claim 5 wherein: said plasticizer compound or composition is selected from the group consisting of: water, alcohols, glycols, oil or combinations thereof; and said compound or composition is selected from the following groups: block copolymer thermoplastic elastomers, styrene block copolymers, and hydrogenated styrene block copolymers, polyacrylics, polyvinyl alcohols, natural gums or gelatins, polyethylene oxides, polyvinylpyrrolidone, ethers polyvinyl, cellulose derivatives, or combinations thereof.

7. A topical adhesive according to any of the preceding claims, characterized in that 80% by weight of said adhesive consists of hydrophobic components and most preferably all the components of said adhesive are hydrophobic. 8.- A protective article, clothes, prosthesis, thermal wraps, pads and / or packaging, cold wraps, healing aids, protective face masks, ornamental or eye wear articles, or functional articles that are cosmetics or pharmaceutical supply items, decorative cosmetics or cleaning articles, said article for the attachment of the topical adhesive to the skin of a user, the article comprising a topical adhesive according to claim 1 for attachment to the skin. 9. The use of a topical adhesive according to claim 1 on protective articles, clothing, prostheses, thermal wrappings, pads and / or packaging, cold wraps, healing aids, protective face masks, ornamental articles or use for eyes, or functional items that are cosmetics or pharmaceutical supply items, decorative cosmetics or cleaning items.