MXPA99004501A - Adhesive composition comprising a polysiloxane - Google Patents

Abstract

A polysiloxane adhesive composition that is useful in attaching products to human skin. A disposable absorbent product may be prepared that includes the polysiloxane adhesive composition and that may be adhered directly to human skin and peeled off after use with little or no pain to the wearer.

Description

ADHESIVE COMPOSITION COMPRISING A POLYISYLOXAN FIELD OF THE INVENTION The present invention relates to an adhesive composition that includes a polysiloxane that is useful in securing products to human skin. More particularly, the invention relates to a disposable absorbent product that includes the adhesive composition and can adhere directly to human skin and can be peeled off after use with little or no pain to the user.

BACKGROUND OF THE INVENTION Disposable absorbent products currently enjoy widespread use in a wide variety of applications. Typical disposable absorbent products include such as those of diapers, adult incontinence products and bed pads, catamenial devices such as sanitary napkins and plugs, and other products such as cleansers, bibs, wound dressings and surgical covers or layers. Disposable absorbent products are generally suitable for absorbing many liquids, such as water or salt water, and body fluids such as urine, menstrual fluids and blood.

The purpose of disposable absorbent products is typically the management of body waste typically. In order to manage the waste of the liquid body, the disposable absorbent product typically includes an absorbent structure which must generally be capable of first taking the liquid into the absorbent structure, then distributing the liquid inside the absorbent structure and then retaining the liquid inside. of the absorbent structure.

In order to obtain the desired liquid handling characteristics of the disposable absorbent product, the disposable absorbent product is generally secured to the wearer's body. As an example, securing a sanitary napkin during use is often accomplished by holding the sanitary napkin to the wearer's undergarment by means of a pressure sensitive adhesive. Securing a sanitary napkin to an undergarment may, however, exhibit a number of disadvantages. A disadvantage is that the adhesive can stick too aggressively to the inner surface of the undergarment leaving a residue. Another disadvantage is that the sanitary napkin will tend to move with the undergarment rather than being associated with the movements of the wearer's body. This can result in a less secure notch and in the increased incidence of fluid run-off, irritation, scaling and discomfort.

In the past, attempts have been made to adhere a sanitary towel directly to a wearer. However, such sanitary napkins generally have to be relatively large enough to prevent the adhesive from being placed in contact with the wearer's public hair and sensitive genitalia. This is because when securing the sanitary napkins in the wearer, such sanitary pads generally use adhesives of the type used in various surgical applications. The removal of these adhesives typically causes a sudden pain or discomfort for the user. Therefore, avoiding the sensitive areas of the user has been necessary.

It would therefore be desirable to have an adhesive composition that could be used to secure a disposable absorbent product directly on the wearer's body that was comfortable for use, that was relatively small and discreet, giving the wearer a sense of safety during use and that will not cause discomfort to the user with the removal.

SYNTHESIS OF THE INVENTION These and other related objects are achieved in the present invention by means of an adhesive composition which can be used to adhere a disposable absorbent article to human skin and hair, and which can be peeled from a wearer very little or no pain, and that generally does not leave an appreciable residue on the user after the removal.

One aspect of the present invention is the pressure sensitive adhesive composition comprising a polysiloxane material exhibiting the desired adhesive properties.

In one embodiment of the present invention, a polysiloxane adhesive composition exhibits an effective shear modulus, hardness, tan delta, and maximum peel strength properties.

In another embodiment of the present invention, a polysiloxane adhesive composition exhibits the following properties: (a) a cut storage modulus value, as measured at 20 ° C and about 10 radians per second, of less than about lxlO5 dynes per square centimeter; (b) a hardness value of less than about 5 durometer units (Shore 00); (c) a tan delta value as measured at around 20oc and at a frequency of about 10 radians per second, from between about 0.4 to about 2.0; Y (d) a maximum peel strength value of between about 35 to about 900 grams of force per 13 millimeters of width, as measured at a peel rate range of from 0 to about 5000 millimeters per minute.

In another aspect, it is desirable to provide a disposable absorbent product, such as a sanitary napkin, which is the disposable absorbent product that includes a pressure sensitive adhesive.

In one embodiment, this objective is achieved in a disposable absorbent product comprising a liquid permeable upper sheet, a lower sheet, an absorbent structure positioned between the upper sheet and the lower sheet, at least one main surface adapted to be placed on a body side of a wearer, and a pressure sensitive polysiloxane adhesive composition bonded to said main surface.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a top plan view of an incorporation of a disposable absorbent product according to the present invention.

Figure 2 is a cross-sectional view of Figure 1 taken along line 2-2.

DETAILED DESCRIPTION OF THE PREFERRED INCORPORATION In one aspect, the present invention relates to a pressure sensitive adhesive composition having improved desirable adhesive properties that can be used to adhere the products directly to the skin and hair of a human user.

As used herein, a "polysiloxane material" is intended to represent a polymeric material that includes alternating oxygen and silicone atoms with hydrogen or various organic groups attached to the silicone.

The pressure-sensitive polysiloxane adhesive composition can generally be formed by curing a mixture of lower alkenyl functional polysiloxane, such as vinyl containing polysiloxane, and a copolymer of polysiloxane containing hydrogen containing active hydrogen groups. As used herein, the term "active hydrogen groups" is meant to refer to hydrogens which are attached directly to a silicone atom, such as silicon hydrides and organopolysiloxanes containing hydrogen. The relative amount of each component to be used to prepare the polysiloxane adhesive will depend on such factors as the molar ratio of the alkenyl radicals to the active hydrogen groups in the uncured composition and the nature of its components, including such variables as the polymer chain length, the molecular weight, and the polymer structure as well as the desired adhesive properties to be exhibited by the adhesive composition.

Other acceptable methods of inducing crosslinking to prepare the desired polysiloxane adhesive composition include silanol condensation, using organic peroxides, using ultraviolet light initiated cross-linking, using free radical initiated hydrosilation, using high energy radiation crosslinking or using electronic beams The starting materials useful in the preparation of the polysiloxane adhesive composition of the present invention, such as the alkenyl polysiloxane- Lower functional and polysiloxane copolymer materials containing hydrogen containing active hydrogen groups are well known and are commercially available from such vendors as Dow Corning Corporation, Wacker Silicones Corporation, and General Electric Corporation.

The components used to prepare the polysiloxane adhesive composition of the present invention can generally be mixed in any manner such as by volume or in an organic solvent. The polysiloxane adhesive composition can generally be prepared, with or without the aid of an organic solvent, by simply mixing together the desired components in effective amounts to achieve the desired adhesive properties described herein. The order of mixing the materials together is generally not critical. A suitable method for preparing the polysiloxane adhesive composition is achieved by using a two part component adhesive formula wherein one component comprises a lower alkenyl functional polysiloxane material and the second component comprises a polysiloxane copolymer material which contains. hydrogen containing active hydrogen groups.

When the materials are mixed together to prepare the polysiloxane adhesive composition, the composition generally begins to cure at a rate which is directly proportional to the temperature of the composition. The polysiloxane adhesive composition can generally be cured at room temperature or at an elevated temperature by heating the composition. A suitable temperature for curing the polysiloxane adhesive composition is between about 75 ° C to about 250 ° C.

Although the main components of the adhesive composition of the present invention have been described above, such an adhesive composition is not limited thereto and may include other components that do not adversely affect the desired adhesive properties of the adhesive composition. The example materials which may be used as additional components will include, without limitation, the pigments, the antioxidants, the stabilizers, the surfactants, the waxes, the flow promoters, the particles, the inhibitors, the catalysts and accelerators, and the materials aggregates to improve the processability of the components.

It has been found that by preparing the polysiloxane material exhibiting the desired adhesive properties described herein, it is possible to prepare a pressure sensitive adhesive that exhibits improved adhesive properties compared to known adhesive materials.

The desired adhesive properties of the polysiloxane adhesive of the present invention include an effective shear modulus value, a hardness value, a tan delta value, and a peel strength value.

As used herein, the term "adhesive" was used to mean that property of any material that allows the material to bond the substrates together by surface bonding. Such bonding can result from the application of a pressing force, in the case of a pressure-sensitive adhesive material or a sufficiently high temperature, in the case of a hot-melt adhesive, to make contact and bond the adhesive material to a substrate .

The peel strength value of an adhesive material is intended to represent the adhesive bond strength of the material. It is desired that the adhesive material does not exhibit a peel strength value which is very high, since it will generally indicate that the adhesive material is very aggressive and that it will therefore generally cause pain with the removal of the wearer's skin. Also, it is desired that the adhesive material does not exhibit a peel strength value which is too low, since it will generally indicate that the adhesive material will generally not remain effectively adhered to the skin of the wearer.

Thus, the adhesive composition of the present invention exhibits a maximum peel strength value that is beneficially between about 35 to about 900 grams of force per 13 millimeters in width, suitably from about 120 to about 750 grams of force by 13 millimeters wide, and more adequately from around 210 to about 360 grams of force per 13 millimeters in width, as measured at a peeling rate ranging from 0 to about 5000 millimeters per minute and as measured according to the methods described in the test methods section given here.

The hardness value of the adhesive material is intended to represent the material resistance to deformation. It is desired that the adhesive material does not exhibit a hardness value that is too high, since it will generally indicate that the adhesive material is very hard for the hair embedded in the adhesive, and therefore, generally will not adhere well to the wearer.

Thus, the adhesive composition of the present invention exhibits a hardness value that is beneficially less than about 5 Durometer units (Shore 00) suitably of less than about 1 Durometer unit (Shore 00), and more adequately of 0 units of durometer (Shore 0) as measured according to the methods described in the test methods section given here.

The delta value of an adhesive material is intended to represent the ratio between the cut loss modulus (G ") and the cut storage modulus (G ') of material.It is desired that the adhesive material does not exhibit such a value. delta that is too high, since this will generally indicate that the adhesive material is very aggressive and will generally cause pain with the removal of the wearer's skin, and it is desired that the adhesive material not exhibit a delta value that is too low since this will generally indicate that the adhesive material exhibits too low adhesion and will therefore generally not remain effectively adhered to the skin of a wearer.

Thus, the adhesive composition of the present invention exhibits a delta value which is beneficially between about 0.4 to about 2.0, suitably from about 0.7 to about 2.0, and more suitably from about 0.7 to about 1.5, as measured at around 20oc and at a frequency of about 10 radians per second, as measured according to the methods described in the test methods section given here.

The value of the storage storage module of an adhesive material is intended to represent the flexibility or stretchability of the material. It is desired that the adhesive material does not exhibit a cut storage modulus value that is too high, since this will generally indicate that the adhesive material is too flexible and by tango will generally be a poor skin adhesive because the adhesive does not it will conform to the movements of the user's body. It is desired that the adhesive material does not exhibit a cut storage modulus value that is too low, since it will generally indicate that the adhesive material lacks sufficient cohesive strength and will generally break and separate and leave residue with the removal of the skin of the user.

Therefore, the adhesive composition of the present invention exhibits a value of shear storage modulus that is beneficially less than about lxlO5 dynes per square centimeter, more beneficially from about lxlO5 to about lxlO3 dynes per square centimeter, suitably less than about 7x104 dynes per square centimeter, and more adequately less than about 2x104 dynes per square centimeter, as measured at around 20oC and about 10 radians per second, as measured according to the methods described in the test methods section given here.

The polysiloxane adhesive compositions of the present invention are useful as pressure sensitive adhesives and will readily adhere to a solid support, whether the solid support is flexible or rigid. The polysiloxane adhesive composition can be applied to a solid support surface by means of any coating means such as rolling, spreading, spraying and the like, and then subsequently cured as described above.

In another aspect, the present invention relates to a disposable absorbent product comprising a polysiloxane adhesive composition as described herein. Disposable absorbent products according to the present invention are suitable for absorbing many liquids, such as water, salt water, synthetic urine, and body fluids such as urine, menstrual fluids and blood, and are suitable to be used as diapers, adult incontinence products, and bed pads; in catamenial devices such as sanitary napkins and plugs; and in other disposable absorbent products such as cleansers, bibs, wound dressings and surgical covers or layers.

The present invention relates generally to disposable absorbent products which are secured to the body of a wearer by means of a pressure sensitive adhesive. In an embodiment of the present invention, there is provided a disposable absorbent product whose disposable absorbent product comprises a liquid-permeable top sheet, a bottom sheet attached to the top sheet, an absorbent structure placed between the top sheet and the bottom sheet, at least a main surface adapted to be placed on one side of the user's body, and a pressure sensitive adhesive composition of the present invention attached to said main surface.

Those skilled in the art will recognize suitable materials for use as the top sheet and the bottom sheet. Examples of materials suitable for use as the topsheet are liquid permeable materials, such as polypropylene or spunbonded polyethylene having a basis weight of from about 15 to about 25 grams per square meter. Examples of materials suitable for use as the bottom sheet are liquid impervious materials, such as polyolefin films, as well as vapor permeable materials, such as microporous polyolefin films.

While one embodiment of the invention will be described in terms of the use of the adhesive composition of the present invention in a disposable absorbent product such as a sanitary napkin, it is understood that the adhesive composition is equally suitable for use in other disposable absorbent products known to those skilled in the art. As used herein, the term "sanitary napkin" refers to a product which is worn by women on one side of the pudenda region and which is intended to absorb and contain various exudates which are discharged from the body, such like blood, menstrual fluids and urine. The sanitary towel is intended to be discarded after a single use. The interlabial devices which reside partially within and partially outside the female user's vestibule are also within the scope of this invention.

For ease of understanding when referring to the figures, similar numbers designate equal parts in the different views and additions. Referring to Figures 1 and 2, an embodiment of a sanitary napkin 10 is shown. Although shown as having generally a race track shape, the sanitary napkin 10 can have any variety of shapes well known to those skilled in the art. such as, for example, hourglass, oval or similar forms. In the most basic embodiment, the sanitary napkin 10 has a pair of longitudinal sides 12 and 14, the transverse ends 16 and 18, an absorbent core 20 and a side-to-body adhesive 22. The sanitary napkin 10 has at least one surface main 24 adapted to be placed on one side of the body of a user. That is, the surface 24 is soft and permeable to liquid. Positioned distally of the surface facing the body 24 is a fluid-impermeable separator 26.

The absorbent core 20 may be any material which is generally compressible, comfortable and non-irritating to the wearer's skin and capable of absorbing and containing exudates from the body such as urine, menstrual fluids, blood and the like. Desirably, the absorbent core 20 maintains its integrity when wetted during use. The absorbent core 20 can be manufactured in different shapes and from a variety of liquid absorbent materials commonly known in the art of disposable absorbent articles. For example, absorbent materials such as cellulose fibers, wood pulp, cellulose fibers or regenerated cotton may be used. Such fibers can be chemically or physically modified. The absorbent core 20 can include any of the fibers mentioned above in combination with other materials, both natural and synthetic, such as hydrophilic foams, hydrophilic polymers or the like. Wood pulp is often the material of choice primarily because it is cheap and readily available. The absorbent core 20 can also include a layer of absorbent and thin material such as tissue, fabric or the like made of cellulosic fibers. The absorbent core 20 can also include one or more superabsorbent materials known in the art. By "superabsorbent" we mean a hydrocolloid material that is capable of absorbing an amount of water which is at least 10 times the weight of the hydrocolloid particles in the dry form and preferably from about 15 to 70 times the dry weight . Such materials are further described in U.S. Patent No. 5,247,072 issued September 21, 1993 to Ning et al., The description of which is incorporated herein and becomes a part thereof.

The separator 26, which is typically impervious to liquid, can be designed to allow air and moisture vapor to pass to the exterior surface while blocking the passage of liquids. The separator 26 can be made from one more polymeric films such as polyethylene, polypropylene, cellophane, or a film / nonwoven laminate and the like. The separator 26 can also be constructed of a liquid permeable material that has been treated or coated to become impermeable to the liquid.

Referring to figure 2, the sanitary napkin includes a liquid-permeable cover 28 having a body facing surface 24. The cover 28 is positioned on one side of the absorbent core 20. The cover 28 which is designed to make contact with the wearer's body can made of several polymeric films and are perforated for the migration of the fluid inside the absorbent core or of woven or non-woven fibers, or of yarns produced from natural or synthetic materials which are easily penetrated by the fluids of the body. Thermoplastic polymer films made of polyethylene or polypropylene are preferred. Other acceptable covers which can be produced by laminating the film and fiber substrates. It may also be beneficial to pierce or etch (not shown) the cover 28 to increase the rate at which body fluids can penetrate down into the absorbent core 20.

The side-to-body adhesive 22 is positioned on one side of the cover 28 in an essentially rectangular, open pattern of adhesive members or small discrete dots 30 to leave numerous areas free of adhesive. The adhesive members 30 may have a surface area of about 0.03 square centimeters (cm2) to about 20 cm2, and preferably from 0.15 cm2 to about 15 cm2. As measured from the face facing surface 24 of the cover 28, the adhesive members 30 may have a thickness of about 0.01 millimeters to about 2 millimeters. The dot pattern of Figure 1 contains approximately the smaller amount of side-to-body adhesive 22 required to obtain sufficient adhesion to achieve the desired result and provide satisfactory removal comfort.

Generally, the adhesive 22 is secured to less than about 90 percent surface area of the body 24, preferably less than about 70 percent of the area and more preferably less than about 20 percent of the area .

It should be understood that any suitable adhesive pattern can be selected to apply the adhesive 22 to the body facing surface 24 of the sanitary napkin 10, provided that it is consistent with the desired concentration of adhesive 22 on the body facing surface 24 but which still allows the sanitary napkin 10 to retain the amount of absorbency required. For example, adhesive patterns can be oval, swirl, several linear or nonlinear oriented longitudinally and / or transversely and reticulated webs having unobstructed interstices between the adhesive no fibers or combinations thereof arrangements adhesive. The adhesive patterns can be opened or closed. By "open" it is required to say that the adhesive may have an intermittent or continuous pattern that does not essentially cover one or more of the transverse ends 16 and / or 18 of the sanitary napkin 10. By "closed" it is meant that the adhesive will surround the absorbent core 20. Preferably, the pattern of adhesive 22 essentially corresponds to the configuration of the absorbent core 20. Desirably, the adhesive 22 is applied to a pattern that is symmetrical about an axis on the which bisects the sanitary napkin 10 and divides the sanitary napkin 10 into essentially equal parts. This gives the user a balanced sensation when using the sanitary napkin 10. This also reduces the perception of any associated discomfort when the sanitary napkin 10 is removed from the body.

The adhesive 22 can be applied to the body facing surface 24 by techniques known in the art. For example, the extrusion or grid printing of the adhesive 22 from one or more nozzles on the face surface 24 as described in commonly assigned United States of America No. 4,995,333 to Keller et al. February 1991, whose full description is incorporated and is part of the same.

Disposable absorbent products according to all aspects of the present invention are generally subjected, during use, to multiple insults of a liquid body. Therefore, the disposable absorbent products are desirably capable of absorbing numerous discharges of body fluids in amounts in which the disposable absorbent products will expand during use. The discharges are generally separated from each other for a period of time.

Test Methods: Peeling resistance the peel strength of an adhesive sample was determined using a 180 ° peel strength test of the Modified Pressure Sensitive Tape Board (PSTC-1) described below. The PSTC-1 is a standardized test procedure that is described in more detail on page 23 of the tenth edition of the Test Methods, copyright 1992, available from the Pressure Sensitive Tape Board of 401 North Michigan Avenue, Chicago, Illinois 60611-4267, whose description is incorporated here and becomes part of the same. The peel strength values were determined according to the following procedure.

A double-sided adhesive tape approximately 13 millimeters wide was secured to the top and bottom edges of a stainless steel test plate, which has dimensions of about 100 millimeters wide and 152 millimeters long. The adhesive tape was 3M # 665, available from 3M Corporation, located at St. Paul, Minnesota. A polyethylene film 0.05 millimeters thick, engraved on the male side, was secured to the double-sided tape with the side engraved with the male as the test surface. Polyethylene film is available from Edison Plástic, located in Washington, Georgia. One end of the polypropylene reinforcing film on which the adhesive sample was molded and cured, for example, the end which will be the leading end, was rigidly secured to a front strip of a non-stretchable material. The front strip must be stronger than the peel strip of the adhesive. The test sample was pressed down onto the polyethylene film with a 2043 gram mechanical roller available from Chemsultant International, of Mentor, Ohio. The 180o peel was immediately conducted on a peel strength tester, such as a Model 810 Material Testing System, available from MTS Corporation, Minneapolis, Minnesota 55424. When the test specimen was placed in the tester, the jaws of the tester were initially placed at a separation of 17.78 centimeters. The steel test panel was secured in the stationary jaw (1.27 centimeters) with the unsecured front strip extending beyond the position of the stationary jaw. The front strip was then folded back and caught in a centered arrangement inside the mobile jaw of the tester. The tester was activated to perform a 180o peel test. The moving jaw moved to a total distance of 20.32 centimeters, with the adhesive tested in the middle of 10.16 centimeters. The peel strength tester can be appropriately programmed to control the peel rate. As used here, the peel strength tester was programmed so that the peel rate was changed to every 2.03 centimeters of distance traveled by the mobile jaw. For the total distance of 20.32 centimeters traveled by the mobile jaw, the mobile jaw started at a rate of about 100 millimeters per minute and subsequently moved at respective rates of 300, 500, 700, 900, 1200, 1800, 2500, 3500 and 5000 milliliters per minute. The peel strength with respect to the distance traveled was recorded on a chart recorder. The peak of the peel strength / distance curve was taken as the maximum peel strength in the peel rate range from 0 to about 5000 millimeters per minute.

Hardness The hardness value of a sample of adhesive was measured using a Shore Hardness tester 00 according to the test method ASTM D-2240-91, the content of which is incorporated herein in its entirety. The hardness tester is available from Shore Instruments Manufacturing Company, of Freeport, New York. The hardness value of a sample of adhesive was reported in units of durometer, based on a Shore 00 scale.

Rheological Properties The rheological analysis of an adhesive sample is a method to determine the viscoelastic properties of the adhesive sample. The rheological measurements were obtained by using a Rheometrics Dynamic Spectrometer, model RDS IIE, available from Rheometrics Inc., of Piscataway, New Jersey, by using the procedures recommended in the operation manual, whose contents are incorporated herein in their entirety. The rheological properties were measured with respect to the adhesive samples having the thickness of between 1 to 4 millimeters The adhesive sample was cut in a circle of 25 mm in diameter and placed between two, 25 mm parallel plate accessories of the spectrometer. The top plate was lowered onto the adhesive sample until a normal strength meter indicated a slight reflection. The shear stress applied to the adhesive sample was about 1 percent. The shear storage modulus and shear loss modulus values for the adhesive sample were measured at around 20oC and around 10 radians per second, and reported in days per square centimeter. The tan delta value for the adhesive sample was measured around 20oC and at a frequency of around 10 radians per second, and was reported as a value without dimension.

Examples: The polysiloxane adhesive compositions were prepared by manually mixing together various amounts of desired materials. Each polysiloxane adhesive composition was prepared as a 40 gram sample.

For Samples 1-5, 10, and 17, a two part component adhesive system was used to prepare the polysiloxane adhesive composition. The component of part A of the adhesive system is a clear liquid and exhibits a Brookfield viscosity at about 25 ° C of about 3250 centipoise. The component of part B of the adhesive system is a clear liquid and exhibits a Brookfield viscosity at around 25oC of around 3200 centipoises. The two part component adhesive system is available from Dow Corning Corporation, under the trade designation Sylgard Silicone Dielectric Gel Q3-6636.

For Sample 1, 3.5 parts by weight of the part A component was used for every 6.5 parts by weight used of component part B.

For Sample 2, 4 parts by weight of the part A component were used for every 6 parts by weight used of the part B component.

For Sample 3, 4.5 parts by weight of the component of part A were used for every 5.5 parts by weight used of the component of part B.

For Sample 4, 5 parts by weight of the component of part A were used for every 5 parts by weight used of the component of part B.

For Sample 5, 5.5 parts by weight of the component of part A was used for every 4.5 parts by weight used of the component of part B.

For Sample 10, 5.5 parts by weight of the component of part A was used for every 5 parts by weight used of the component of part B.

For Sample 17, 4.5 parts by weight of the component of part A were used for every 6 parts by weight used of the component of part B.

For Samples 7, 12, 14, 16 and 18, three materials were used to prepare the polysiloxane adhesive composition. The first material was a crosslinkable, crosslinkable polydimethylsiloxane resin system containing trimethylated silica, tetra (trimethyl siloxy) silane, and dimethyl siloxane, dimethylvinyl terminated, which is a colorless to pale yellow liquid having a specific durability at 25 ° C. about 1.05, a viscosity of about 35,000 centistokes, and that is available from Dow Corning Corporation, under the designation Adhesive 7938 from Dow Corning. The second material was a noble metal complex catalyst comprising the finished dimethylvinyl polydimethylsiloxane, tetramethyldivinyl disiloxane, and platinum siloxane complex, and is available from Dow Corning Corporation under the trade designation Syl-Off 4000 catalyst. The third material was the polydimethylsiloxane fluid. having a viscosity of around 100,000 centistokes and which is available from Dow Corning Corporation, under the trade designation Fluid Dow Corning 200.

For Sample 7, 10 parts by weight of the crosslinkable polydimethylsiloxane resin system per each 0.1 parts by weight weight of the noble metal complex catalyst used was used. A polydimethylsiloxane fluid was not used.

For Sample 12, 36 parts by weight of the crosslinkable polydimethylsiloxane resin system were used per each 0.44 parts by weight used of the noble metal complex catalyst and 4 parts by weight used of the polydimethylsiloxane fluid.

For Sample 14, 38 parts by weight of the crosslinkable polydimethylsiloxane resin system were used per each 0.4 parts by weight of the catalyst used. noble metal complex and 2 parts by weight used of the polydimethylsiloxane fluid.

For Sample 16, 39.5 parts by weight of the crosslinkable polydimethylsiloxane resin system were used per each 0.4 parts by weight used of the noble metal complex catalyst and each 0.6 parts by weight used of the polydimethylsiloxane fluid.

For Sample 18, 38.9 parts by weight of the crosslinkable polydimethylsiloxane resin system were used per each 0.44 parts by weight weight of the noble metal complex catalyst and each 1.5 parts by weight used of the polydimethylsiloxane fluid.

For Samples 8 and 11, a system of two component parts was used to prepare the polysiloxane adhesive composition. The component part A of the adhesive system is a mixture of polydimethylsiloxane including polydimethylsiloxane and methylvinyl polydimethylsiloxane, is a translucent liquid exhibiting a specific gravity of between about 1.04 to about 1.17 and is available from Wacker Silicones Corporation under the designation Elastosil LR 3003 / 20A US. The component of part B of the adhesive system is a mixture of polydimethylsiloxane that includes polydimethylsiloxane and methyl vinyl polydimethylsiloxane, it is a translucent liquid exhibiting a specific gravity of between about 1.04 to about .18 and is available from Wacker Silicons Corporation under the designation Elastosil LR 3003 / 20B US.

For Sample 11, 5 parts by weight of the polydimethylsiloxane mixture of part A was used for every 5 parts by weight used of the polydimethylsiloxane mixture of part B.

For Sample 8, 3 parts by weight of the polydimethylsiloxane mixture of part A were used for every 1 parts by weight used of the polydimethylsiloxane mixture of part B.

For Samples 13 and 15, an adhesive system of 2 component parts was used to prepare the polysiloxane adhesive composition. The component part A of the adhesive system is a clear liquid. The component part B of the adhesive system is a clear liquid. The two part component adhesive system is available from Dow Corning Corporation under the trade designation Sylgard Silicone Dielectric Gel Q3-6575.

For Sample 13, 5.5 parts by weight of the component of part A was used for every 5 parts by weight used of the component of part B.

For Sample 15, 6 parts by weight of the component of part A were used for every 4 parts by weight used of the component of part B. For each sample, the materials described in the indicated quantities were mixed by hand together in a container of small plastic. A mold was prepared having a length of about 7.5 inches and a width of about 3. 5 inches. The mold consisted of a reinforced polypropylene film having a thickness of about 0.0015 inches and is available from Edison Plastics of Washington, Georgia, located between two sheets coated with fluorocarbon tetrafluoroethylene polymer, each having a thickness of about 1. / 16 inch and available from EI DuPont de Nemours Co. , of Wilmington, Delaware. The top fluorocarbon tetrafluoroethylene polymer coated sheet had two parallel mold cavities, each with a width of about 0.25 inches and a length of about 5 inches and about 2 inches outward from each other, through its thickness. The one-inch attaching fasteners were placed on the respective lateral edges of the assembly to hold the assembly together.

The sample of polysiloxane adhesive was then poured into the cavities of two moles in the upper part of the upper tetrafluoroethylene fluorocarbon polymer coated sheet, for a thickness of about 1/16 of an inch The mold assembly was then placed in an oven with air circulation at about 123 ° C for about 30 minutes. The assembly was then removed from the oven and allowed to cool to room temperature (about 23 ° C). The attaching fasteners and the upper and lower fluorocarbon tetrafluoroethylene polymer coated sheets were removed from the polypropylene film coated with adhesive. These polypropylene samples coated with adhesive were then used for the peeling test. The results of these evaluations are shown in Table 1.

Samples of the polysiloxane adhesive compositions were then prepared for suitably rheological evaluations. A mold was prepared by cutting a square of 4 inches by 4 inches through a sheet coated with fluorocarbon tetrafluoroethylene polymer having a length of about 5 inches, a width of about 5 inches, and a thickness of about 1 / 16 inch. This mold was supported by another sheet coated with tetrafluoroethylene fluorocarbon polymer having similar length, width and thickness dimensions. The two sheets coated with fluorocarbon tetrafluoroethylene polymer were held together using bonding fasteners. The polysiloxane adhesive sample was poured into the mold cavity in the upper part of the top fluorocarbon tetrafluoroethylene polymer coated sheet, by a Thickness of about 1/16 of an inch. The mold assembly was then placed in an air circulation oven at about 123 ° C for about 30 minutes. The assembly was then removed from the oven and allowed to cool to room temperature (about 23 ° C). The fasteners and binders and the top tetrafluorocarbon polymer coated sheet were removed from the bottom tetrafluoroethylene fluorocarbon polymer coated sheet. This sample of adhesive was then peeled from the sheet coated with fluorocarbon tetrafluoroethylene polymer and then used for the rheological test. The results of these evaluations are shown in Table 1.

Those skilled in the art will recognize that the present invention is capable of any modifications and variations without departing from the scope thereof. Therefore, the detailed description and examples set forth above are intended to be illustrative only and not intended to limit in any way the scope of the invention as set forth in the appended claims.

Table 1 Storage Module Resistance of our Cutting Tan Maximum Peel Hardness Number (dynes / cm2) Delta (Shore 00) (qramos force) * 1 - - 12 0 * 2 2.81x10"0.35 0 3 * 3 2.60xl04 0.44 0 6 4 2.11xl04 0.60 0 124 5.80xl03 0.82 0 360 * 2.00X105 0.47 32 > 1200 * 8 - - 65 0 10 1.43X104 0.77 0 212 * 11 1.71xl05 0.48 16 35 * 12 9.36xl04 0.21 15 140 * 13 4.46xl03 0.15 0 85 * 14 1.38xl05 0.24 20 365 2.20xl03 0.45 0 118 * 16 8.08xl04 0.49 25 898 * 17 2.36xl04 0.48 0 10 * 18 l.llxlO5 0.43 25 840 It is not an example of the present invention.

Claims (11)

R E I V I N D I C A C I O N S

1. A disposable absorbent product comprising: i) a liquid-permeable top sheet, a bottom sheet attached to the top sheet, an absorbent structure positioned between the top sheet and the bottom sheet, and at least one main surface adapted to be placed adjacent to the wearer's body; Y ii) a polysiloxane adhesive composition bonded to said main surface, wherein the polysiloxane adhesive composition exhibits the following properties: a) a cut storage modulus value, as measured at around 20oc and about 10 radians per second, of less than about lxlO5 dynes per square centimeter. b) a hardness value of less than about 5 durometer units (Shore 00); c) a tan delta value, as measured at around 20oc and at a frequency of about 10 radians per second, from between about 0.4 to about 2.0; Y d) a maximum peel strength value of between about 35 to about 900 grams of force per 13 millimeters of width, as measured at a peel rate in the range of 0 to about 5000 millimeters per minute.

2. The disposable absorbent product as claimed in clause 1, characterized in that the maximum peel strength value is between about 120 to about 750 grams of force per 13 millimeters of width.

3. The disposable absorbent product as claimed in clause 2, characterized in that the maximum peel strength value is between about 210 to about 360 grams of force per 13 millimeters of width.

4. The disposable absorbent product as claimed in clause 1, characterized in that the hardness value is less than about one unit of durometer (Shore 00).

5. The disposable absorbent product as claimed in clause 4, characterized in that the hardness value is around 0 durometer units (Shore 00).

6. The disposable absorbent product as claimed in clause 1, characterized in that the delta value is between about 0.7 to about 2.0.

7. The disposable absorbent product as claimed in clause 6, characterized in that the delta value is between about 0.7 to about 1.5.

8. The disposable absorbent product as claimed in clause 1, characterized in that the value of shear storage modulus is between about lxlO5 to about lxlO3 dynes per square centimeter.

9. The disposable absorbent product as claimed in clause 1, characterized in that the value of shear storage modulus is less than about 7x104 dynes per square centimeter.

10. The disposable absorbent product as claimed in clause 9, characterized in that the cut storage module value is less than about 2x104 dynes per square centimeter.

11. The disposable absorbent product as claimed in clause 1, characterized in that the polysiloxane adhesive composition is formed by the SUMMARY A polysiloxane adhesive composition that is useful for holding products on human skin. A disposable absorbent product can be prepared by including a polysiloxane adhesive composition and which can adhere directly to the human skin and peel off it after use with little or no pain to the wearer. curing a mixture of a lower alkenyl functional polysiloxane and a polysiloxane uric acid copolymer containing hydrogen groups active.