KR20000069665A - Breathable disposable absorbent article for topical adhesive attachment to the skin of a wearer - Google Patents

Abstract

The present invention relates to breathable absorbent products, in particular sanitary napkins, panty liners, adult incontinence products or sweat pads. In particular, the present invention relates to a breathable absorbent article that is worn by attaching directly to the wearer's skin in areas where body fluid absorption is desired.

Description

Breathable disposable absorbent article for topical adhesive attachment to the skin of a wearer}

Conventional linear techniques in the field of disposable absorbent products for topical application to the wearer's skin have been developed in particular in disposable bands, plasters and bandages. Such products are often breathable, but typically these products are usually applied in emergencies where the wearer's skin ruptures and tries to absorb the fluids secreted from the wound. In this regard, aspects of comfort and ease of use and application, painless removal and separation of absorbent product performance are based on criteria such as wound sterility, support for healing recovery, and mechanical protection. In addition, absorbent products covering such wounds are most often attached to areas of the skin where hair can be removed or little or no hair grows prior to application of the absorbent product.

The present invention is not directed to absorbent articles covering wounds but to breathable absorbent articles for absorbing body fluids that are naturally secreted from the body even if a wound does not occur. For example, sanitary napkins or pantyliners in the genital area are such products. Also for example, breathable incontinence devices worn in the genital area or sweat pads worn under the armpits of breathable patients are the subject matter of the present invention.

When such a product is applied topically to the wearer's skin, it is typically the criterion of whether a significant amount of hair grows and the product can be removed easily and painlessly. Such products are typically described in US Invention Code H1602 or WO 96/33683. Some of the more detailed descriptions of these products are described in WO 95/16242. This patent discloses a sanitary napkin with a body adhesive applied along its entire circumference on a wearer facing surface of the sanitary napkin. The underlying problem with this patent is mainly related to firm adhesion to the skin, but also mentions the problem of detaching the product after use without causing severe pain to the wearer.

International Patent Publication No. 95/16424 discloses in more detail the criteria for body adhesives in terms of fluidity criteria. However, since the taught fluidity criteria include commercially available hair loss (ie, hair removal) compositions, such as STREP MIELE®, which is commercially available from Laboratori Vaj SpA, Italy, this patent discloses pain relief of the product. Very little consideration is given to the problem of detaching without. Topical adhesives mentioned in WO 95/16424 include current pressure sensitive adhesives used to attach sanitary napkins to undergarments. In addition, the patent only confirms the static flow characteristics of the body adhesive and does not refer to the dynamic flow characteristics.

International Publication No. 96/13238 discloses a body adhesive model that is frequency dependent. However, for example, all measurements disclosed on page 9 were made at temperatures between −60 and + 120 ° C. and actual frequencies between 0.1 and 100 rad / sec. At the application temperature (typical bathroom, ie storage temperature of about 20 ° C.), the Williams-Landel-Ferry (hereinafter WLF) equation was used to obtain the required data.

This WLF equation is an empirical formula and is valid only at certain limits, so it cannot be used to extrapolate to temperatures below the glass transition temperature of the polymer adhesive, nor can WLF be used based on values obtained below the glass transition temperature. A detailed description of the WLF equation and its application can be found in Z. Tadmor and CGGogos, published by Principles of Polymer processing, published by John Wiley & Sons, or JDFerry, Viscoelastic. Properties of Polymers, John Wiley & Sons. It is not described in WO 96/13238, so the application of the disclosed data cannot be evaluated. In addition, this description does not relate to breathable self-adhesive products.

EP 638 303 discloses the use of a body adhesive on the side cuff of a sanitary napkin to hold the cuff in an upright position. Swiss Patent Publication No. 643730 discloses the use of a very long sanitary napkin with a rounded outer edge, with the adhesive applied to the body at four corners of the outer edge to provide a body adhesive region sufficiently outside of the pubic growth region. Doing.

In addition, the definition of this body adhesive and its formulation have been improved nowadays to improve the direct attachment of absorbent products to the skin. However, due to this close wearing condition, it is also a problem because the absorbent articles contain an impermeable plastic film on their outer surface. As a result, sweat and temperature rise within the product as generally described as "stuffiness", which would not be acceptable to the sensitive wearer of the wearer of such a product. Since these products provide breathability through the wearer's opposing side, this problem is substantially arising for products attached to the wearer's skin as compared to products adhered to the garment.

On the basis of the foregoing in the prior art, the object of the present invention is a body fluid which is naturally secreted from the wearer's body, which adheres to the wearer's skin, can remove the absorbent product without pain, and does not become uncomfortable with "turtle" It is to provide a disposable absorbent product for absorbing. Another object of the present invention is to ensure that no adhesive remains on the skin or hair when peeled off. Another object of the present invention is to provide an absorbent product which is worn very closely to the wearer's body fluid leakage area without the hassle caused by wearing too closely, thereby reducing or suppressing the leakage of liquid out of the absorbent product. . Disposable absorbent products worn in the crotch region of the wearer will improve the barrier to contaminating surrounding skin tissue and clothing.

The application of these products to the wearer's skin, in addition to the aforementioned objectives of the present invention, prevents odors from being absorbed and prevents the outflow of odors from absorbed liquids or odors formed from absorbed liquids reaching the absorbent products. Liners and sanitary articles are preferred because they reduce or eliminate odors arising from the product.

The present invention relates to breathable absorbent products, in particular sanitary napkins, panty liners, adult incontinence products or sweat pads. In particular, the present invention relates to a breathable absorbent article that is worn by attaching directly to the wearer's skin in areas where body fluid absorption is desired.

The present invention relates to a breathable disposable absorbent article for topical attachment with an adhesive to a wearer of such article. Breathable products include outward surfaces, typically referred to as wearer facing and garment facing, based on the product worn under the garment. The garment facing surface of a sanitary napkin using conventional sanitary napkins and body adhesives is generally impermeable to liquid, air and water vapor. In contrast, the products of the present invention provide at least breathability for water vapor, since the effect of heat dissipation is greatest due to water vapor permeability. However, the garment facing surface of the article is also preferably air permeable without compromising liquid impermeability, which is an essential element for leakage.

In particular, in a preferred embodiment according to the invention, the backsheet comprises a perforated molded film, wherein the perforation is funnel shaped with a primary opening at the funnel inlet and a maximum opening at the funnel outlet. This perforated molded film is located in the backsheet of the breathable absorbent article such that the maximum opening is adjacent the absorbent core rather than the basic opening.

In another preferred embodiment according to the invention, a breathable backsheet having at least first and second layers is provided on the wearer facing surface. The layers are arranged such that the first layer is closer to the absorbent core than the second layer, preferably the first layer is an air permeable perforated film and the second layer is a microporous film or a meltblown nonwoven substrate as described above. to be.

The breathable article includes an absorbent core structure between the wearer facing surface and the garment facing surface to absorb liquid that naturally leaks from the wearer. The breathable disposable absorbent article according to the present invention comprises an adhesive for topically attaching the article to the wearer's skin at least in part of the wearer's opposing face.

In a preferred embodiment, the adhesive has an elastic modulus at 37 ° C. (100 ° F.) abbreviated as G ′ ₃₇ , and a viscous modulus at 37 ° C. (100 ° F.) abbreviated as G ″ _37. Such adhesive is at 100 rad / sec frequency of G 'is a difference of ₃₇ G in 1rad / sec "" ₃₇ and 1rad / sec in G from the frequency _"37 between the G, or 150% of ₃₇ or less, preferably 80 or less, preferably a 10000pa under dynamic acoustic aspects In addition, the adhesive has a difference in G ″ ₃₇ between G ″ ₃₇ at 100 rad / sec frequency and G ″ ₃₇ at 1 rad / sec frequency of 10000 Pa or less, preferably 5000 Pa or less, more preferably Is chosen to have a dynamic viscosity aspect that represents 1000 Pa.

It is particularly preferred that the product according to the invention has a ratio of G ′ ₃₇ / G ″ _{37 in} the entire frequency range of 1 to 100 rad / sec of at least 1, preferably at least 1.6 and most preferably at least 3.3.

For at least 1 to 100 rad / sec frequency region G _'37 / G "value of ₃₇ ratio can be varied by frequency increases, it is not necessarily proportional to the change in frequency. G' ₃₇ / G" ₃₇ in the This ratio to the ratio should not vary more than three times, preferably more than two times, in the region of the frequency, and most preferably maintain a constant number.

In 1rad / sec, and a preferred G 'value of ₃₇ is less than 20000 Pa, preferably below 15000 Pa, most preferably less than 10000 Pa. On the other hand, the value of G ″ ₃₇ at 1 rad / sec should not exceed 15000 Pa, preferably less than 10000 Pa, most preferably less than 5000 Pa. The above-mentioned rheological criterion is at 20 ° C. 51% to 99.5% by weight of a plasticizer compound or composition which is a liquid, 0.5 to 20% by weight, preferably 5 to 15% by weight, and 0 to 600% by weight of the adhesive resin (soluble or swellable to the plasticizer compound or composition) Plastic compounds or compositions are preferably water, alcohols (preferably glycerol), glycols, polyglycols, liquid polybutenes, oils and their And the polymeric compound or composition is preferably a block-copolymer-thermoplastic-elastomer, styrene-block copolymer and hydrogen Styrene block is selected from the group consisting of copolymers.

In general, preferred body adhesives are at least partially hydrophobic, preferably consisting of hydrophobic components, preferably 60%, more preferably 80% by weight, based on the weight of the adhesive, most preferably any material in the adhesive. Not as hydrophilic. That is, they are not manufactured entirely from hydrophobic components.

In a particularly preferred embodiment according to the invention, the adhesive covers less than 20% or more preferably less than 10% of the wearer facing surface of the invention. The present invention is most usefully applied in the field of sanitary napkins or pantyliners.

The present invention relates to a breathable disposable absorbent product that is applied directly to the skin of a user. Due to its breathability and mode of application, the product provides excellent absorbability for body fluids, prevents contaminants from contaminating your garments, and improves the physical comfort you experience, and is easy to manufacture and pack. Breathable disposable absorbent products are described below for sanitary napkins or sanitary articles, but specifically include pantyliners, adult incontinence products, or sweat pads. As used herein, the term “physiological zone” is intended to be worn by a woman adjacent to the vulva region, to absorb and contain various body fluids (eg, vaginal discharge, menstrual blood, and / or urine) that are discharged from the body, Refers to a product intended to be discarded after one use. The disposable absorbent article is preferably thin, more preferably 1 to 5 mm thick, and may be substantially flat or preformed before use.

The term "connected" or "attached" herein refers to an arrangement in which the first member immediately follows the second member, and an intermediate member in which the first member is connected to the second member so that the first member is connected to the second member. Indirectly followed by a configuration.

In a preferred embodiment, the sanitary napkin of the present invention comprises a liquid permeable topsheet, a liquid impermeable but breathable backsheet connected to the topsheet, and an absorbent core between the topsheet and the backsheet. The sanitary napkin has two main surfaces, a body contact surface or a wearer facing surface, and a garment facing surface or contact surface.

The top sheet is supple, soft and non-irritating to the wearer's skin. The topsheet may also have elastic properties so that it may extend in one or two directions or in its extension in a portion of the topsheet. In addition, the top sheet is liquid permeable to allow easy penetration of liquid (eg menstrual blood and / or urine) through its thickness. Suitable top sheets include woven and nonwoven fabrics; Polymeric materials such as perforated molded thermoplastic films, perforated plastic films, and hydroformed thermoplastic films; And thermoplastic scrims. Suitable fabrics and nonwovens can be natural fibers (eg wood or cotton fibers), synthetic fibers (eg polymeric fibers such as polyester, polypropylene, or polyethylene fibers), or mixtures or bicomponents / of natural fibers and synthetic fibers / It may consist of multicomponent fibers.

Preferred topsheets for use in the present invention typically include high loft nonwoven topsheets and perforated molded films. Perforated molded films are preferred for topsheets because they are permeable or nonabsorbable to body secretions and have less tendency to reflow the liquid to wet the wearer's skin again. Thus, the surface of the molded film in contact with the body is kept dry, thereby making the body less dirty and giving the wearer a more comfortable feeling.

Suitable molding films are described in US Pat. No. 3,929,135; US Patent No. 4,324,246; US Patent No. 4,342,314; US Patent No. 4,463,045; And US Pat. No. 5,006,394. Particularly preferred microperforated molded film topsheets are described in US Pat. No. 4,609,518 and US Pat. No. 4,629,643. Preferred topsheets for absorbent articles of the present invention are described in one or more of the above patents, and are referred to as "DRI-WEAVE" by The Procter & Gamble Company, Cincinnati, Ohio. It is a molded film commercially available in physiological objects.

A topsheet in which the liquid passage path is not evenly distributed and only a part of the topsheet has the liquid passage path can also be expected in the present invention. Typically such topsheets will have a liquid passage path oriented such that the center is permeable to the liquid and impermeable to the perimeter.

The wearer facing surface of the molded film top sheet may be hydrophilic to allow for faster liquid transfer through the top sheet than when the body surface is not hydrophilic. In a preferred embodiment, the surfactant is incorporated into the polymerizable material of the film topsheet shaped as disclosed in WO93 / 09741. Alternatively, the wearer facing surface of the topsheet may be treated with a surfactant to become hydrophilic as disclosed in US Pat. No. 4,950,254.

Alternatively, so-called hybrid topsheets incorporating fibrous and film-like structures, particularly useful embodiments of such hybrid topsheets are described in WO 93/09744, WO 93/11725, or WOA. 93/11726.

For topsheets, multilayer or monolayer structures are envisaged. The above-mentioned hybrid topsheet is such a multilayer design, but other multilayer topsheets, such as the first and second topsheet designs, are also contemplated.

The absorbent structure or absorbent core comprises: a first fluid distribution layer comprising the following components: (a) preferably a second optional fluid distribution layer; (b) a fluid storage layer; (c) an optional fibrous (dusting) layer under the storage layer and (d) other optional components.

a. First / second fluid distribution layer

One optional component of the absorbent structure according to the present invention is a first fluid distribution layer and a second fluid distribution layer. The first distribution layer is typically placed under and in fluid communication with the top sheet. The top sheet moves the fluid to the first distribution layer for final distribution of the captured fluid to the storage layer. The movement of the fluid through the first distribution layer occurs not only through the thickness but also along the length of the absorbent article and the direction of the butterfly. In addition, an optional but preferred second distribution layer is typically in fluid communication with the bottom of the first distribution layer. The purpose of the second distribution layer is to easily capture fluid from the first distribution layer and quickly move it to the underlying storage layer. This makes full use of the fluid capacity of the underlying storage layer. The fluid distribution layer can be made from any material typical of such distribution layers. In particular, the fiber layer is useful as a distribution layer even during infiltration by maintaining interfiber capillary pressure.

b. Fluid storage layer

The fluid storage layer is placed in fluid communication with the first or second distribution layer and typically lies below them. The fluid storage layer may comprise any common absorbent material or combination thereof. These preferably include an absorbent gelling material, generally referred to as a "hydrogel", "superabsorbent", "hydrocolloid" material, in combination with a suitable carrier.

The absorbent gelling material can absorb large amounts of aqueous body fluid and can further retain this absorbed fluid under moderate pressure. The absorbent gelling material is homogeneously or heterogeneously dispersed in a suitable carrier. Suitable carriers can be used alone as long as they are absorbent.

Absorbent gelling materials suitable for use herein most often include substantially water insoluble, slightly crosslinkable, especially neutralized, polymerizable gelling materials. This material forms a hydrogel upon contact with water. Such polymeric materials can be prepared from unsaturated polymerizable acid containing monomers known in the art.

Suitable carriers include materials commonly used in absorbent structures, such as natural, modified or synthetic fibers, especially modified or unmodified cellulose fibers, in the form of fluff and / or tissue. Suitable carriers can be used with the absorbent gelling material, but they can be used alone or in combination. In sanitary napkins and pantyliners, tissues or tissue laminates are most preferred.

Embodiments of an absorbent structure made in accordance with the present invention include a bilayer tissue stack formed by folding tissue thereon. These layers can be bonded to each other. Absorbent gelling material or any other material may be included between the layers.

Modified cellulose fibers, such as rigid cellulose fibers, can also be used. Synthetic fibers may also be used, including cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics (eg Orlon), polyvinyl acetate, insoluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (eg Nylon), polyester, bicomponent fibers, ternary fibers, mixtures thereof, and the like. Preferably, the fiber surface is treated to be hydrophilic or hydrophilic. The storage layer may also include fillers such as perlite, diatomaceous earth, vermiculite and the like to improve liquid retention.

Even if the absorbent gelling material is heterogeneously dispersed in the carrier, the storage layer may be partially homogeneous and have a distribution gradient in one or several directions within its dimensions. Heterogeneous distribution may also relate to a carrier stack that partially or completely surrounds the absorbent gelling material.

c. Optional fiber ("dusting") layer

Any component contained in the absorbent structure according to the present invention is a fibrous layer adjacent to and typically below the storage layer. This underlying fiber layer is typically referred to as a "dusting" layer because it provides a substrate on which the absorbent gelling material accumulates in the storage layer during the manufacture of the absorbent structure. Indeed, when the absorbent gelling material is in the form of a large structure such as a fiber, sheet or strip, such a fiber "dusting" layer need not be included. However, these "dusting" layers provide additional fluid handling capability, such as rapid suction of fluid along the length of the pad.

d. Any other component of the absorbent structure

The absorbent structure according to the present invention may include any other component generally present in the absorbent web. For example, the reinforcing scrim can be placed in or between each layer of the absorbent structure. Such reinforcing scrims should be shaped so that they do not form an interface barrier to fluid movement. Since structural integration generally occurs as a result of thermal bonding, reinforcing scrims are generally not needed for heat bonded absorbent structures.

Another component which may be included in the absorbent structure according to the invention and which is provided in close proximity to or as part of the first or second fluid distribution layer is an odor inhibitor. In addition to activated carbon coated odor removers or other odor inhibitors, particularly suitable zeolite or clay materials are optionally incorporated into the absorbent structure. These components may be incorporated in any desired form but are often included as separate particles.

Back sheet

The absorbent article according to the invention comprises a breathable backsheet as an essential element. The main role of the breathable backsheet is to ensure that secretions absorbed and blocked in the absorbent product do not wet the product in contact with the absorbent product, such as pajamas and undergarments. To this end, the backsheet typically extends throughout the absorbent structure and may be folded around the absorbent structure to extend into the topsheet to form part of the topsheet. In this way the structure of the topsheet as described in lines 47 to 62 of US Pat. No. 4,342,314 16 may optionally be produced without the need to perforate the topsheet.

The breathable backsheet not only prevents liquid from moving through the backsheet, but can also permeate water vapor, preferably both water vapor and air, through the backsheet, so that air enters the inner sheet of the backsheet and the absorbent product itself. Allow it to circulate.

Suitable breathable backsheets for use herein may be selected from all breathable backsheets known in the art. Theoretically, there are two types of breathable backsheets, namely backsheets which are breathable but impermeable to a liquid and only a single layer, and at least two layers which are breathable and liquid impermeable. As used herein for a breathable backsheet, the term "liquid impermeable" means blocking the outflow of liquid from the product. Thus, in principle, products into which liquid enters through the breathable backsheet are not excluded by this term.

Suitable monolayer breathable backsheets for use herein include British Patent 2184 389, British Patent 2184 390, British Patent 2184 391, United States Patent 4 591 523, and United States Patent 3 989 867. , US Patent No. 3 156 242 and European Patent Application 95120653.1.

Suitable double or multilayer breathable backsheets for use herein include U.S. Patent No. 3 881 498, U.S. Patent 4 341 216, U.S. Patent 4 713 068, U.S. Patent 4 818 600, Europe Patent 203 821, European Patent 710 471, European Patent 710 472, European Patent Application 95120647.3, European Patent Application 95120652.3, European Patent Application 95120653.1 and European Patent Application 96830097.0 I can hear that.

Particular preference is given to backsheets which meet the requirements defined in European Patent Application No. 96830343.8, and in general it is more preferred that the absorbent product meet the requirements as described above.

According to the invention, the breathable backsheet comprises at least one, preferably at least two water vapor permeable layers. Suitable water vapor permeable layers include two-dimensional flat fine and microporous films, monolithic films, macroscopically expanded films and molded perforated films. According to the invention, the perforation of the layer may be of any structure but is preferably spherical or elliptical. In addition, the size of the perforations may vary. In a preferred embodiment, the perforations are preferably evenly distributed over the entire surface of the layer, but one may expect a layer having only a perforated surface.

As used herein, two-dimensional flat films include perforations with an average diameter of 5 to 200 μm. Typically, the average diameter of the perforations of the two-dimensional flat microporous film suitable for use herein is 150 μm to 5 μm, preferably 120 μm to 10 μm, most preferably 90 μm to 15 μm. The average diameter of the perforations of a typical two dimensional flat macroporous film is 200 to 90 μm. Macroscopically expanded films and shaped perforated films (3-dimensional films) suitable for use herein are typically 100-500 μm in diameter. In an embodiment according to the invention in which the backsheet comprises a macroscopically expanded film or a perforated molded film, the backsheet comprises typically an open area of at least 5%, preferably 10 to 35% of the surface area of the total backsheet. something to do.

Suitable two-dimensional flat layers of the backsheet may be made of any material known in the art, and are preferably made of commercial polymeric materials. Suitable materials are, for example, known in the art as being applied in so-called breathable garments, for example GORE-TEX or Sympatex®. Other suitable materials include XMP-1001 from Minnesota Mining and Manufacturing Company, St. Paul, Minnesota, USA. As used herein, the term two-dimensional flat layer refers to layers having a depth of less than 1 mm, preferably less than 0.5 mm, wherein the perforations have an average uniform diameter along their length and It does not protrude from the face. Perforated materials for use as backsheets in the present invention may also be prepared using any method known in the art as described in EP 293 482 and references therein. In addition, the size of the perforations made in this way may be increased by applying a force across the face of the backsheet layer (ie, stretching the layer in a single axis or in a double axis).

Suitable perforated molded films include films (three-dimensional films) comprising individual perforations extending toward the core under the horizontal plane of the garment facing side of the layer to form protrusions. At the end of the projection is a hole located. Preferably the protrusion is funnel similar to that described in US Pat. No. 3,929,135. The holes located at the terminal ends of the perforations and protrusions located in the plane may themselves be circular or non-circular, provided that the size or area of the transverse cross-section of the perforations where the size or area of the cross section of the holes of the protrusions is located on the facing side of the layer or It must be smaller than the area. Preferably, such perforated molded film is at least substantially unidirectional with the ability to move the liquid in a direction towards the core (although not completely unidirectional). Macroscopically expanded films suitable for use herein include, for example, the films described in US Pat. No. 4 637 819 and US Pat. No. 4,591,523.

Suitable monolithic films include Hytrel, commercially available from DuPont Corporation, USA. Other such materials are described in Index 93 Congress, Session 7A "Adding value to Nonwovens", J-C. Cardinal and Y. Trouilhet, DuPont de Nemours Internationl S.A., Switzerland.

According to the invention, the backsheet comprises an additional backsheet layer in addition to the water vapor permeable layer. The additional layer may be located on both sides of the water vapor permeable layer of the backsheet. The additional layer may consist of any material, for example a fibrous nonwoven layer, in particular a hydrophobic fiber, which will preferably improve the liquid transfer resistance of the backsheet while maintaining the basic breathability of the meltblown fibers or articles. It may also consist of additional water vapor permeable layers as described above.

Adhesive for topical attachment

The product according to the invention as described above is applied directly to the skin of the user. In particular, it is applied around the humoral secretion area, which is typically the genital part of a female user. The term "skin" according to the invention refers not only to the specific dermis of the user, but also to the mucosal tissue, and also to the hair generally present in the genital area of the sanitary napkin user.

In order to secure the product according to the invention to the skin, it is necessary to provide an adhesive for topical attachment, referred to as an adhesive for the body, to a particular area of the side of the topsheet of the product facing the wearer.

Various designs are contemplated in this respect, but preferably the body adhesive is provided along the circumferential edge of the topsheet such that the central area of the product remains free of adhesive. This would be easiest to place the liquid-permeable topsheet containing no adhesive adjacent to the hole where the body fluid is secreted so that the secreted liquid is immediately moved into the absorbent structure of the absorbent article without the possibility of leaking or spilling.

However, the body adhesive does not have to be provided in a closed circle along the circumference of the topsheet, and the repetitive parts, such as dots or dashed lines, to provide additional comfort to the wearer of these products due to the separation between the adhesive areas. It may be provided as.

In order to satisfy the object according to the invention, the following must be considered.

Physical, fluid and adhesive features of body adhesives

Although body adhesives, such as pressure sensitive adhesives, are used on the hair and mucosal tissues of human skin, the body adhesive compositions are referred to as typical pressure sensitive adhesives (hereinafter referred to as PSAs) based on the most characteristic fluid aspect identifying the substance. There is a difficulty to regard.

Indeed, as those skilled in the art of adhesives know, the biggest feature that distinguishes PSAs from other materials that can temporarily stick objects (e.g. water) is their fluid parameters, in particular elastic modulus (G '). This depends on the frequency of the stress applied. More specifically, the G 'of the PSA can increase by more than a number of orders as the frequency of the applied stress varies from a typical binding frequency to a typical resolution frequency, ie from 1 rad / sec to 100 rad / sec as described above. have.

As a first result, it is concluded that it is unacceptable to define a substance to be used as an "adhesive" by providing a fluid variable value, especially a G 'value at a fixed frequency. This may be misjudged because it may include materials that have no practical value in the absence of other features. Therefore, fluid features should be based on dynamic considerations.

This applies not only to the elastic modulus G 'but also to the viscous modulus G "and thus also to tan (δ) = G" / G'. A typical PSA not only has a high variation of G 'over the frequency considered, but also a larger variation of G " that is closer to or much higher than the G' value (i.e., tan (δ) in particular in the typical frequency of the solution). About 1 or even greater than 1) is well known.

Although not constrained by theory, this means that much of the energy applied to the solution sum is dissipated by internal friction (and therefore not effective in generating the solution sum), which means that it has a record that macroscopic adhesion is very high. Can be interpreted.

In order to provide good bonding conditions (ie at a frequency of about 1 rad / sec), the absolute value of the elastic modulus must not be too high, otherwise the adhesive is too hard and it cannot be closely connected or molded to the surface to be bonded. It is also important to have an absolute value of low G " in order to provide good tack which is particularly useful for direct application to the human body while gently adhering the material to the skin in a soft state.

Finally, one skilled in the art will recognize that the glass transition temperature (Tg) of PSA is a very useful factor in defining a group of useful PSA materials.

As mentioned above, the material useful as the body adhesive according to the present invention has a flow characteristic mainly measured at a reference temperature of 37 ° C. (general body temperature of humans) and a range of frequencies. In the application of absorbent articles comprising body adhesives, it has been found that the contact of the adhesive is formed at a low frequency, whereas the solution quickly peels off when resolved. This rate was expressed in 100 rad / sec frequency, while the low frequency of adhesive bond was found to be on the order of 1 rad / sec. The frequency region for use according to the invention is therefore 1 rad / sec to 100 rad / sec and must satisfy the following characteristics:

(1) in the region of the frequency, the elastic modulus G and the "rate of change ₃₇ is 1rad / sec G 'less than 150% of _37, preferably less than 100%, more preferably less than 80%, preferably gradient is It is less than 10000 Pas in absolute value. This is met by the body adhesive for which is illustrated in the following, while for Pro meon which is incorporated in the art example (Promeon) Since RG-63B may be a frequency G 'gradient is 331% of ₃₇ in the same area, It is not acceptable in the present invention.

In the range of said frequency, the rate of change of the viscosity modulus G " ₃₇ is 10000 Pa or less, preferably 5000 Pa or less, more preferably 1000 Pa or less.

The ratio of G ′ ₃₇ / G ″ ₃₇ in the frequency region of 1 rad / sec to 100 rad / sec is preferably at least 1, more preferably at least 1.6, most preferably at least 3.3, while preferably about It should not exceed 50.

G 'and G "at a frequency of 1 rad / sec in application should be measured at 37 ° C. In practice, in the use of the product according to the invention, the actual storage temperature of the product and the temperature of the body adhesive in the application will vary widely. For example, the temperature may reach about 37 ° C. if stored in a hot toilet near a heater, but will be close to 0 ° C. if stored in a storage room or toilet with no heating and windows open. Because the product according to is used directly on the skin and the wearer typically does not want to wear too cold product, the actual temperature of the body adhesive will reach 37 ° C. very quickly, and even the wearer may warm up before application. Therefore, the bonding properties of the adhesive are chosen to be most suitable at body temperature.

As mentioned above, the rheological aspect relates to the value of Tg, which is the glass transition temperature. In the body adhesive according to the invention, the Tg is preferably below -15 ° C, more preferably below -20 ° C, most preferably below -25 ° C.

Chemical and Compositional Characteristics of Body Adhesives

The following formulation criteria may additionally be used to meet the requirements of the fluid and physical characteristics of the body adhesive. It should be noted that most of the compositions useful as body adhesives have a substantially gel-like structure and are preferably gels. This is derived from the following facts.

(1) The main component is a liquid substance at room temperature.

(2) Macromolecules or polymerizable components are present in small amounts relative to the plasticizer. They form, in a preferred embodiment, three-dimensional networks generated by physical or chemical bonds between molecules. Particularly useful are the physical bonds present in systems containing block thermoplastic elastomers.

More specifically, the composition typically comprises the following components.

(1) 0.5 to 20% by weight, preferably 5 to 15% by weight, of macromolecular polymerizable materials or mixtures thereof that can be dissolved or swelled in the plasticizer (s) mentioned below. By way of non-limiting example, examples of such macromolecules or polymerizable materials include natural and / or synthetic products, such as natural gums or derivatives such as natural gums and gelatin, derivatives and alginates thereof; Polyacrylic; Polyvinyl alcohol; Polyethylene oxide; Polyvinylpyrrolidone (PVP) or polyvinyl ether, copolymers and derivatives thereof; Cellulose derivatives; Block copolymer thermoplastic elastomer, preferably styrenic block copolymer, more preferably hydrogenated grades of styrol / ethylene-butylene / styrene (SEBS), styrene / isoprene / styrene (SIS) and styrol / ethylene-propylene / Styrol (SEPS).

(2) 51 to 99.5% by weight of a plastic material or plastic material mixture that is liquid at room temperature. By way of non-limiting example, the plasticizer can be water, various alcohols (particularly glycerol), glycols, polyglycols, liquid polybutenes, natural or synthetic oils such as vegetable oils, mineral oils or combinations thereof.

(3) 0 to 600% by weight, based on macromolecular polymerizable material, of a tacky resin whose main range is particularly suited to the glass transition temperature in systems containing synthetic polymers.

(4) 0-10% by weight, more preferably 0-5% by weight, for promoting and stabilizing the gel formation process of both hydrophilic or hydrophobic liquid plasticizers. These include, for example, oily systems, fatty acids having 8 to 22 carbon atoms, metal salts thereof, polyoxo-derivatives thereof; Lanolin derivatives; Silica; Bentonite, montmorillonite and derivatives thereof; Polyamides, waxes or mixtures thereof.

Conventional additives known in the art, such as preservatives, antioxidants, UV inhibitors, pigments, mineral fillers, rheology modifiers and the like, may each be included in amounts up to 10%.

When chemical crosslinks are formed in the system, the crosslinkers may be present in an amount of preferably up to 5% by weight. Chemical crosslinkers can be formed by mutual neutralization of polymers with different functional groups, such as in the reaction between acid polyacryl and polysaccharide.

The present compositions for body adhesives can be divided into the following three groups depending on the nature of the main component (generally liquid plasticizer (s)).

(1) A hydrophobic composition wherein the plasticizer is typically an oil derived from a vegetable or mineral source or a blend thereof and the polymer is a synthetic polymer, preferably an elastomer, generally capable of dissolving or swelling in the oil (s).

(2) Mixed-phase compositions wherever possible, in both plasticizers and polymers, both hydrophobic and hydrophilic components form two or more separate phases. In this case the emulsifier / surfactant is preferably present in an amount suitable to form a stable emulsion between incompatible phases. In the case of the body adhesive according to the present invention, it is preferable that the main body consists mainly of a hydrophobic component as compared to the hydrophilic component;

(3) Hydrophilic compositions, typically wherein the plasticizer is water / glycerol / glycol and / or mixtures thereof and the like and the polymer phase originates from a synthetic (eg polyacrylic) or natural (eg natural gum) source or mixtures thereof.

In contrast to the prior art and medicinal fields described above, it is emphasized that hydrophobic and mixed phase compositions 1) and 2) above are preferred for use in the present invention, while hydrophilic compositions are not preferred.

This depends in part on technical reasons in that many hydrophilic compositions used in the medical field exhibit too low elastic properties and adhesion for use in the present invention. Another reason for favoring hydrophobic or mixed phase compositions is that the application of the present invention, particularly in the field of sanitary napkins, involves the possibility of contact with the liquid to be absorbed by the body adhesive. Since all liquids to be absorbed are generally of an aqueous type, contact with a hydrophilic body adhesive can result in some body fluids being absorbed into the body adhesive.

This, in turn, changes the rheological properties to alter the functionality of the body adhesive, which not only causes an unsanitary appearance but also causes body fluids to come into direct contact with the skin for a long time, which is a disposable absorbent according to the present invention. It is not typically required by the product. In addition, hydrophilic compositions may also pose potential drawbacks for the user as they are potentially good culture media for the growth of many microorganisms, including pathogens.

In addition, hydrophilic body adhesives are cold or wet when applying new sanitary napkins, or armpit sweat pads do not live up to typical consumer expectations. Another problem also arises from the fact that body adhesives, including water as plasticizers, tend to be dehydrated unless they are sealed as impermeable packaging.

Absorbent articles according to the invention can be prepared by methods customary in the art. The application of the adhesive to the top sheet of the absorbent article may be provided by similar techniques commonly used for panty fixed adhesives, so such applications will not cause major problems for those skilled in the art. The entire wearer facing surface area of the absorbent article covered with the body adhesive should be 20% or less, preferably 10% or less. Preferably the adhesive is close to the perimeter of the absorbent article and in the case of the film top sheet (or when the back sheet is folded over the top sheet) the adhesive is preferably on a portion of the film which is liquid impermeable.

Body adhesives on the product (as in panty fixed adhesives) need to be protected before use. Such protection may be provided by a release liner, such as paper treated with siliconization or surfactant, wherein the paper has a good release surface for a specially selected body adhesive.

In principle, the absorbent article according to the invention is supported by the body adhesive to the wearer and does not require additional support for fixing. However, a non-slip coating may be provided on the back sheet side of the sanitary napkin for the purpose of preventing the sanitary napkin form from slowly deviating from its position. In addition, even if panty anchoring adhesives are not intended and thus undesirable for the present invention, they are not completely excluded from the scope of the present invention.

Example 1

The oil-based compositions useful in the present invention are 9.9% by weight of Kraton G-1651, Witko, a styrene / ethylene-butylene / styrene block copolymer sold from Shell Co. and containing 33% by weight of styrene. It is formulated using 59.3% by weight of Kaidol, a paraffinic mineral oil commercially available from Witco Co.

Moreover, the composition contains 301 parts of the tacky resin per 100 parts of the Kraton polymer. The adhesive resin is Escorez 5300, a hydrogenation resin commercially available from Exxon Co.

Magnesium stearate, available from Carlo Erba S.p.A., is used as an auxiliary gelling agent for oils at a concentration of 0.7% by weight.

Irganox 1010, an antioxidant commercially available from Ciba-Geigy, is added at a concentration of 0.3% by weight.

Thus, the final blend has the following weight percentages:

Kraton G-1651 9.9% by weight

Kaidol 59.3% by weight

Escorts 5300 29.8% by weight

Magnesium Stearate 0.7% by weight

Aganox 1010 0.3 wt%

The composition exhibits the following rheological properties at 37 ° C .:

and a) an elastic modulus G _'37 is 6876Pa at 1rad / s,

and b) a non-elastic G _'37 / G _"37 of the modulus and the viscous modulus at 1rad / sec is 12.49,

And the ratio G _'37 / G _"37 of the elastic modulus and the viscous modulus at 100rad / sec is 7.01,

c) a ratio of 1.308 of the ₃₇ 'at G 100rad / sec to about _37' from the G of 1rad / sec.

The formulation was judged to be comfortable when applied to sensitive hair with a lot of hair.

Comparative Example

7.1% by weight of Kraton G-1651, a styrene / ethylene-butylene / styrene block copolymer sold by Shell Company and containing 33% by weight of styrene, and 41.9% by weight of kaidol, a paraffinic mineral oil marketed by Witko Company. Comparative oil-based composition is blended.

The composition also contains 704 parts of tacky resin per 100 parts of the Kraton polymer. The adhesive resin is Regalerez 3102, a hydrocarbon resin commercially available from Hercules Co.

Magnesium stearate, available from Carlo Erva S.P.A, is used as an auxiliary gelling agent for oils at a concentration of 0.7% by weight.

The antioxidant Aganox 1010, available from Ciba-Geigy, is added at a concentration of 0.3% by weight.

Thus, the final blend has the following weight percentages:

Kraton G-1651 7.1% by weight

Kydol 41.9% by weight

Regalez 3102 50.0% by weight

Magnesium Stearate 0.7% by weight

Aganox 1010 0.3 wt%

The composition exhibits the following rheological properties at 37 ° C .:

and a) an elastic modulus G _'37 is 3059Pa at 1rad / s,

b) a ratio G _'37 / G _"37 of the elastic modulus and the viscous modulus at 1rad / sec is 2.53,

And the ratio G _'37 / G _"37 of the elastic modulus and the viscous modulus at 100rad / sec is 0.74,

c) a ratio of 4.944 'G in 100rad / sec for _{37' 37} G at 1rad / sec.

The combination was found to be very uncomfortable when applied to forearm skin. Hair could not be applied to many sensitive skins.

Claims (10)

Has a wearer facing surface and a garment facing surface, An absorbent core between the wearer facing surface and the garment glad surface, (1) the garment facing surface is at least water vapor permeable to provide breathability to the absorbent article, (2) the absorbent article includes a complex for topically attaching the article to at least a portion of the wearer facing surface, (3) the adhesive has an elastic modulus at 37 ° C. (100 ° F.), G ′ ₃₇ and a viscosity modulus at 37 ° C. (100 ° F.), G ″ ₃₇ , 4, and the adhesive is 100rad / sec in G G _'37 and 1rad / sec frequency G in "between ₃₇ at frequencies less than 150% of' the difference between the ₃₇ G at 1rad / sec" _37, preferably of less than 10000Pa Selected to have a dynamic elastic modulus, 5, the adhesive is 100rad / sec is G G "at ₃₇ a difference between" ₃₇ and G at 1rad / sec frequency _"37 in the frequency 10000 Pa or less, preferably selected to have a dynamic viscosity pattern indicating below 5000 Pa Characterized by Breathable disposable absorbent article for topical attachment with adhesive to the wearer of the article. The method of claim 1, A breathable absorbent article wherein G ′ ₃₇ is less than 20000 Pa, preferably less than 15000 Pa, most preferably less than 10000 Pa at a frequency of 1 rad / sec. The method according to claim 1 or 2, A breathable absorbent article wherein the value of G ″ ₃₇ at a frequency of 1 rad / sec is less than 15000 Pa, preferably less than 10000 Pa, most preferably less than 5000 Pa. The method according to any one of claims 1 to 3, 51 wt% to 99.5 wt% plasticizer compound or composition, wherein the adhesive is liquid at 20 ° C .; 0.5 wt% to 20 wt% of a soluble or swellable polymeric compound or composition in the plasticizer compound or composition; A breathable absorbent article comprising 0% to 600% by weight of the adhesive resin (based on the weight of the polymeric compound or composition). The method of claim 4, wherein The plasticizer compound or composition is selected from the group consisting of water, alcohols, glycols, oils and mixtures thereof, wherein the polymeric compound or composition is a block-copolymer-thermoplastic-elastomer, styrene-block copolymer and hydrogenated styrene block copolymer Breathable absorbent product selected from the group consisting of: The method according to any one of claims 1 to 5, 80% by weight of the adhesive consists of hydrophobic components, most preferably all components of the adhesive are hydrophobic. The method according to any one of claims 1 to 6, A breathable absorbent article wherein the adhesive covers less than 20%, preferably less than 10%, by weight of the wearer's facing surface. The method according to any one of claims 1 to 7, The wearer facing surface is provided by an air permeable backsheet, wherein the backsheet comprises a perforated molded film, preferably the perforation is funnel shaped with a basic opening at the funnel inlet and a maximum opening at the funnel outlet, perforated A breathable absorbent article, wherein the maximum opening of the molded molding film is disposed adjacent the core than the base opening. The method according to any one of claims 1 to 8, The wearer facing surface is provided by a breathable backsheet comprising at least a first layer and a second layer, the backsheet is arranged such that the first layer is adjacent to the core relative to the second layer, and preferably the first layer is An air permeable perforated molded film, most preferably the second layer is a microporous film or a meltblown nonwoven substrate. The method according to any one of claims 1 to 9, Breathable absorbent product that is a sanitary napkin or pantyliner.