Method of making polydiorganosiloxane adhesive with mask and articles

Abstract

A method of making an adhesive article is described comprising: a) providing a mask between a layer of a polydiorganosiloxane composition and a source of radiant energy, wherein the mask comprises one or more openings that exposes a portion of the layer of polydiorganosiloxane composition covers a portion of the layer of polydiorganosiloxane composition; b) crosslinking the layer of the polydiorganosiloxane composition with radiation such that the portion of the layer of polydiorganosiloxane composition exposed through the one or more openings of the mask has greater crosslinking than the portion covered by the mask. In some embodiments, the mask is a mask substrate that is permanently bonded to the layer of polydiorganosiloxane after crosslinking. In other embodiments, the mask is a release liner mask that may be removed from the layer of polydiorganosiloxane after crosslinking. In yet other embodiments, the mask is a non-contact processing mask. Also described are adhesive articles, such as medical articles including medical tape, bandages, and wound dressing; and methods of use.

Description

[0001] METHOD OF MAKING POLYDIORGANOSILOXANE ADHESIVE

[0002] WITH MASK AND ARTICLES

[0003] Summary

[0004] A method of making an adhesive article comprising: a) providing a mask between a layer of a polydiorganosiloxane composition and a source of radiant energy, wherein the mask comprises one or more openings that exposes a portion of the layer of polydiorganosiloxane composition covers a portion of the layer of polydiorganosiloxane composition; b) crosslinking the layer of the polydiorganosiloxane composition with radiation such that the portion of the layer of polydiorganosiloxane composition exposed through the one or more openings of the mask has greater crosslinking than the portion covered by the mask. In some embodiments, the mask is a mask substrate that is permanently bonded to the layer of polydiorganosiloxane after crosslinking. In other embodiments, the mask is a release liner mask that may be removed from the layer of polydiorganosiloxane after crosslinking. In yet other embodiments, the mask is a non-contact processing mask.

[0005] Also described are adhesive articles, such as medical articles including medical tape, bandages, and wound dressing.

[0006] In one embodiment, the adhesive article comprises a layer of a crosslinked polydiorganosiloxane composition having two major surfaces, a first major surface comprising a pressure sensitive adhesive and a second major surface bonded to a mask substrate comprising at least one opening that exposes a film backing of the crosslinked polydiorganosiloxane composition.

[0007] In another embodiment, the adhesive article comprises a layer of a crosslinked polydiorganosiloxane composition having two major surfaces, a first major surface comprising a pressure sensitive adhesive and a second major surface bonded to a mask substrate; wherein the first major surface comprises a portion covered by the mask substrate and a portion exposed through openings of the mask substrate and the exposed portion comprises greater crosslinking than the covered portion.

[0008] In another embodiment, the adhesive article comprises a layer of a crosslinked polydiorganosiloxane composition having two major surfaces, a first major surface comprising a pressure sensitive adhesive and a second major surface comprising a film backing wherein the first major surface comprises a first portion comprising greater crosslinking than adjacent an portion.

[0009] Brief Description of the Drawings

[0010] FIG. 1 A is a top plan view of an embodied mask;

[0011] FIG. IB is a top plan view of the crosslinked assembly of layers comprising a mask substrate;

[0012] FIG. 2 is a schematic side view of an embodied method;

[0013] FIG. 3 is a schematic side view of an embodied article comprising a crosslinked layer of a polydiorganosiloxane composition disposed between a mask and a release liner substrate; FIG. 4A and 4B are top plan views of other embodied articles (e.g. wound dressing) comprising a mask substrate frame;

[0014] FIG. 5 is a top plan view of an embodied mask;

[0015] FIG. 6 is a schematic side view of an embodied article comprising a crosslinked layer of a polydiorganosiloxane composition disposed between a release liner and mask substrate that further comprises a carrier substrate;

[0016] FIG. 7 is a top plan of an embodied article prepared from the mask of FIG. 5;

[0017] FIG. 8 is a top plan view of an illustrative mask suitable for providing a stiffening system;

[0018] FIG. 9A is a top plan view of an article comprising a mask substrate frame and stiffening system; FIG. 9B is a schematic side view of the article of 9 A at the location of the dashed line of FIG 9 A;

[0019] FIG. 10 is a top plan view of an article comprising a mask substrate frame, a stiffening system, and an opening suitable for insertion of a tube;

[0020] FIG. 11 is a top plan view of an embodied article comprising a mask substrate frame having a stiffening system, and an absorbent pad disposed between the release liner and crosslinked layer of a polydiorganosiloxane composition;

[0021] FIG. 12 is a schematic view of another article comprising a mask substrate, a stiffening system, a crosslinked layer of a polydiorganosiloxane composition, an absorbent pad and release liner; FIG. 13 is a top plan view of the article of FIG. 12 comprising the stiffening system of FIG. 11;

[0022] FIG. 14 is a schematic view of another embodied (e.g. surgical drape) article comprising a mask substrate with openings, a crosslinked layer of a polydiorganosiloxane composition, and a release liner.

[0023] Method of Making

[0024] With reference to FIG. 2, a schematic side view of an embodied method of making an adhesive article, the method generally comprises providing a layer of polydiorganosiloxane composition 220 between a mask 201 and source of radiant energy 275. In typical embodiments, the mask is a mask substrate that is permanently bonded to the layer of polydiorganosiloxane after crosslinking. In other embodiment, the mask is a release liner mask that may be removed from the layer of polydiorganosiloxane after crosslinking. In yet another embodiment, the mask is a non-contact processing mask, such as a metal mask. The non-contact processing mask is sufficiently proximate the layer of polydiorganosiloxane during crosslinking, but typically does not contact the polydiorganosiloxane.

[0025] In typical embodiments, a layer of (e.g. uncrosslinked or partially crosslinked) polydiorganosiloxane composition is applied to a substrate 240, such as release liner as previously described, with any suitable dispenser 250, such as an extruder. The layer of the polydiorganosiloxane composition comprises a first major surface 221 proximate the substrate. In some embodiments, a mask substrate or release liner mask 201 is contacted with the opposing surface 223 of the layer of polydiorganosiloxane composition 220. FIG. 1 is a top plan view of an illustrative mask 101 comprising one or more openings 110 through the thickness of the mask. The method further comprises exposing the opposing second major surface 223 of the layer of the polydiorganosiloxane composition to radiation thereby crosslinking the layer of the polydiorganosiloxane composition. Generally, the chamber is inerted (e.g., the oxygencontaining room air is replaced with an inert gas, e.g., nitrogen) while the samples are e-beam crosslinked. During crosslinking the portion of the layer of polydiorganosiloxane composition that is present within the one or more openings of the mask is exposed to a greater dosage of radiant energy and therefore has greater crosslinking than the portion covered by the mask.

[0026] FIG. 3 is a schematic side view of a layer of polydiorganosiloxane composition 320 disposed between a mask substrate or release liner mask 301 and release liner substrate 340. The layer of polydiorganosiloxane composition 320 comprises a first major surface 321 proximate the release liner substrate 340 and a second opposing major surface 323 covered in part by the mask. The major surfaces are substantially parallel to each other and the thickness of a layer or layers is orthogonal to the major surfaces. The mask substrate 301 is absent at the location of the mask substrate opening(s) 310. During crosslinking, the portion of the layer of the polydiorganosiloxane composition 325 that is exposed through the one or more openings 310 of the mask is exposed to a greater dosage of radiant energy than the portion covered by the mask. Thus, the portion of the layer of the polydiorganosiloxane composition 325 that is exposed through the one or more openings 310 of the mask has higher crosslinking and lower tack than the adjacent portion(s) 324, 325 of the layer of polydiorganosiloxane covered by mask substrate 301 during crosslinking. Conversely, the portion of the layer of polydiorganosiloxane composition that is covered by the mask substrate 301 is exposed to a lower dosage of radiant energy than the portion of the layer of the polydiorganosiloxane composition 325 that is exposed through the one or more openings 310 of the mask.

[0027] In some embodiments, the same polydiorganosiloxane composition can be used to manufacture both the wound-contact surface, i.e. surface 323 of exposed portion 325 and the adjacent skin-contact pressure sensitive adhesive surface, i.e. surface 321 of portions 324, 326 due to the difference in radiant energy dosage exposure. In other embodiments, the layer of the polydiorganosiloxane composition may comprise two or more layers of different polydiorganosiloxane compositions, as will subsequently be described with respect to FIG. 9B. Thus, the wound-contact surface, adjacent skin-contact pressure sensitive adhesive surface and opposing film backing surface comprise crosslinked polydiorganosiloxane composition^). In this embodiment, the medical article may lack other film backings such as a polyurethane film backing, particularly at the second opposing surface of the wound-contact surface.

[0028] When the mask is a mask substrate 301 that contacts the uncrosslinked or partially crosslinked polydiorganosiloxane layer prior to crosslinking, the mask substrate 301 is typically permanently bonded to the layer of polydiorganosiloxane composition 320, except for the location of the opening(s) in the mask substrate 301. In typical embodiments, substrate (240, 340, 640) is a (e.g. continuous) release liner that lacks openings. During use, the release liner 340 is removed and the article and applied to a patient such surface 323 of exposed portion 325 is in contact with a wound and surface 321 of portions 324 and 326 covered by masked substrate 301 are bonded to the skin surrounding the wound. In some embodiments, the mask is a release liner mask.

[0029] Various release liners are known and commercially available. The release liners may comprise a polyester terephthalate support film and a release coating. Other support films for release coatings include polyolefins (e.g. polyethylene, polypropylene), and paper. In some embodiments, the release coating may be a fluorositicone material. Release coatings that are free of silicone materials and / or fluorinated materials have also been described for use with polydiorganosiloxane adhesives.

[0030] Release liners are often characterized as having light, medium, or heavy release based on the peel force required to remove the pressure sensitive adhesive of the adhesive article from the release liner. This can be measured according to EN ISO 29862, Annex B (Self-adhesive tapes - Measurement of peel adhesion from a surface at an angle of 90°) using a SP-2100 peel tester from IMass, Inc. equipped with a 10 Ibf load cell and a peel rate of 30 cm / min. When a heavy release is desired, the peel force required to remove the pressure sensitive adhesive of the adhesive article from the release liner may be at least 40 g / inch (2.54 nm) or greater. When a light release is desired, the peel force required to remove the pressure sensitive adhesive of the adhesive article from the release liner may be less than 10 or 5 g / inch (2.54 nm). When a medium release is desired, the peel force required to remove the pressure sensitive adhesive of the adhesive article from the release liner may be greater than 10 and less than 40 g / inch (2.54 nm).

[0031] Various release liners are commercially available including release liners from Siliconature Spa (Godega di Sant'Urbano, Italy), under the trade designation “SILFLU”; and from Toray as the trade designation Cerapeel™’. POLYSILK™ silicone release liners from Loparex International B.V. (Apeldoom, The Netherlands), 3M™ Scotchpak™ 9741 release liner from 3M Company (St Paul, MN), and perfluorinated release chemistries as disclosed in US 4,472,480.

[0032] In some embodiments, a thicker layer of the same polydiorganosiloxane composition is crosslinked from one side providing a crosslink gradient. However, in other embodiments the layer of polydiorganosiloxane composition may be exposed to more than one pass of radiation or (e.g. different intensities of) radiation from both sides. The polydiorganosiloxane composition(s), thickness, and crosslinking conditions are selected such that the first major surface (e.g. 321) proximate the (e.g. release liner) substrate is a pressure sensitive adhesive and the opposing second major surface (i.e. closer to the radiant energy source) 323 and the exposed portion 325 forms a film backing. In some embodiments, covered portions 324 and 326 together with the mask substrate can form a film backing.

[0033] In another embodiment, the polydiorganosiloxane layer may be formed by coating more than one layer of the same polydiorganosiloxane composition. For example, a first layer may be applied to the release liner substrate, a porous substrate applied to the first layer, and a second layer applied to the porous substrate, such as described in cofiled US Application No. 63 / 595859; incorporated herein by reference.

[0034] In another embodiment, the polydiorganosiloxane composition may comprise more than one layer of different polydiorganosiloxane compositions. FIG. 9B is a cross sectional view of an embodied article comprising a first layer of a polydiorganosiloxane composition, 920B (e.g. applied to a release liner substrate), and a second layer of a different polydiorganosiloxane composition, 920A (e.g. applied to the first layer). In one embodiment, the polydiorganosiloxane composition of the second layer 920 A comprises little or no (e.g. silicate) tackifying resin as compared to the polydiorganosiloxane composition of the first layer 920B. In another embodiment, the polydiorganosiloxane composition of the first layer 920B comprises an additive such as an antimicrobial agent (e.g. silver material) or pharmaceutical agent, whereas the polydiorganosiloxane composition of the second layer 920A comprises little or no of such additives. In yet another embodiment, the polydiorganosiloxane composition of the first layer 920B may comprise an additive such as an antimicrobial agent or pharmaceutical agent and tackifying resin; whereas the second layer 920A may lack such additives and tackifying resin. Various other combination of different polydiorganosiloxane compositions can be selected by one of ordinary skill in the art.

[0035] In total thickness of the polydiorganosiloxane layer is typically at least 250 microns. The thickness of the polydiorganosiloxane layer is typically no greater than 1000, 900, 800, or 700 microns. In some embodiments, the thickness is no greater than 650, 600, 550, 500, 450, 400, 350, 300, or 250 microns. However, when the polydiorganosiloxane layer comprises multiple layers, the induvial layers may have thickness less than 250 microns.

[0036] In typical embodiments, the polydiorganosiloxane composition is crosslinked through exposure to E-beam irradiation. In some embodiments, the coating may be crosslinked through exposure to gamma irradiation. In some embodiments, a combination of electron beam crosslinking and gamma ray crosslinking may be used. For example, in some embodiments, the coating may be partially crosslinked by exposure to electron beam irradiation. Subsequently, the coating may be further crosslinked by gamma irradiation. Commercially available electron beam generating equipment is available such as a Model CB-300 electron beam generating apparatus (available from Energy Sciences, Inc. (Wilmington, MA), also described in US 8,541,481. Commercially available gamma irradiation equipment includes equipment often used for gamma irradiation sterilization of products for medical applications.

[0037] In some embodiments, the polydiorganoxiloxane material is exposed to E-beam radiation having a voltage of at least 200, 250, or 300 kV. The voltage of E-beam radiation is typically no greater than 500, 450, 400, 350, or 300 kV. The total dosage of (E-beam) radiation is typically at least 8, 9, 10, 11, 12, 13, 14, or 15 MRad. In some embodiments, the total dosage of (E-beam) radiation is typically no greater than 25 or 20 MRads. The intensity and total exposure is based on the electron beam generating apparatus and the time of exposure. It is appreciated that in the present invention, the first major surface and second opposing major surface of the polydiorganosiloxane layer receive different dosages of (E- beam) radiation. Mask Substrate and Articles

[0038] The mask comprises a mask substrate, release liner mask, or non-contact processing mask having one or more openings. FIG 1A is a top plan view of an illustrative mask (e.g. substrate or release liner mask) 105 comprising one or more opening 110. In top plan view, the total surface area of the openings can be at least 25, 30, 35, 40, 45, 50 or greater% of the total surface area of the mask. The surface area of a single opening in top plan view is typically at least 1, 2, 3, 4, or 5 square centimeter. The total surface area of the one or more opening can range up to 10, 15, or 20 square centimeters or larger. The size of the opening(s) of the mask is the same as the size of the crosslinked layer of the polydiorganosiloxane composition that exposed through the openings of the mask substrate.

[0039] FIG. IB is a top plan view of a crosslinked assembly of layers comprising a mask (e.g. substrate 105). The crosslinked layer of the polydiorganosiloxane composition 120 is exposed through the openings in the mask. The crosslinked layer of the polydiorganosiloxane composition 120 is also present below and in some embodiments permanently bonded to the mask substrate 105 (as depicted in the schematic side views). In some embodiments, the mask comprises a plurality of openings wherein each opening is an individual (e.g. medical) article 115 formed by cutting the crosslinked assembly of layers in the cross-web direction at locations 121 between the openings. The crosslinked layer of the polydiorganosiloxane composition 120 that is exposed through the openings in the mask substrate may be characterized as a film backing layer (i.e. at the opposing surface) or wound contact layer (i.e. at the first major surface proximate the release liner substrate. The crosslinked layer of the polydiorganosiloxane composition 120 that is exposed through the openings of the mask substrate is transparent or translucent such that the wound can be viewed through such layer.

[0040] The mask substrate is typically comprised of a natural or synthetic organic material that allows for transmission of e-beam and / or gamma radiation. The masking substrate can be made from a variety of (e.g. thermoplastic) organic polymeric materials such as polyesters, polyurethanes, polyamides (e.g. nylon), poly imides, and polyolefins).

[0041] The masking substrate is typically a soft, flexible, conformable, non-irritating and non-sensitizing material. In some embodiments, the masking substrate is a moisture vapor permeable films, or a porous substrate including perforated fdms, and fibrous webs including woven fabric, nonwoven, knit webs, and scrim.

[0042] Suitable moisture vapor permeable films may comprise (e.g. thermoplastic) polymethanes such as available under the trade designation PELLETHANE or ESTANE from Lubrizol, Brecksville, Ohio; elastomeric polyesters such as available under the trade designation HYTREL from El. duPont deNemours & Co., Wilmington, Del.; and polyether block amides such as available under the trade designation PEB AX from Elf Altochem North America, Philadelphia, Pa. Other useful films are those described in U.S. Pat. No. 4,499,896 (Heinecke); U.S. Pat. No. 4,598,004 (Heinecke); and U.S. Pat. No. 5,849,325 (Heinecke et al). However, since the mask substrate does not come in contact with the wound, a wide variety of other substrates may be suitable such a (meth)acrylic films, and polyolefins. Typically, the mask substrate has a higher tensile strength and lower elongation than the crosslinked layer of the polydiorganosiloxane composition and thus can provide reinforcement and improve web handling. In some embodiments, the masking substrate material has a maximum tensile strength (ASTM D 412) of at least 20, 30 or 40 MPa and typically no greater than 60, 50 or 40 MPa. In some embodiments, the masking substrate material has a maximum elongation (ASTM D 412) of at least 100, 200 or 300, 400, or 500% and typically no greater than 1000, 750, or 500%. In some embodiments, the thickness of the mask substrate film is at least 25, 50, 75 microns. In some embodiments, the thickness of the mask substrate film in no greater than 200, 150, or 100 microns. In some embodiments, a thicker mask substrate films may be preferred to form frame portions having a smaller width.

[0043] Fibrous mask substrates can be made from the same natural and synthetic organic materials as previously described. Fibrous webs can also be made from various organic fibers such as cotton, wool, hemp, and flax). Fibrous webs come in many forms including, e.g., woven webs, non-woven webs, knits, scrims, and meshes.

[0044] The fibrous mask substrates may have a basis weight of at least 15, 20, 25, 30, 35, 40, 45 or 50 g / m2. The fibrous mask substrate typically has a basis weight of no greater than 200, 150, or 100 g / m2. The thickness of the fibrous mask substrate is typically at least 0.05 mm (50 microns), 0.10 mm (100 microns) or 0.15 mm (150 microns). In some embodiments, the thickness of the fibrous mask substrate is no greater than 0.5 mm (500 microns), 0.4 mm, 0.3 mm, or 0.2 mm. The strand count of the fibrous mask substrate is typically at least 5, 10, 15, 20, or 25 strands per inch (2.54 cm). In some embodiments, the strand count of the fibrous mask substrate is no greater than 100, 150, 100, 75, or 50 strands per inch (2.54 cm).

[0045] The mask can have various designs. In some embodiments, the mask comprises one or more opening having a same (e.g. repeating) geometric shape such as a polygon (e.g. triangle, square, rectangle, etc.), oval, ellipse, hexagons, etc. The geometric openings typically comprise rounded comers. It is appreciated that medical articles, including wound dressings are available is various sizes and shapes depending on the medical article. Illustrative medical articles include medical tapes, bandages, wound dressings, IV site dressings, compression wraps, surgical drapes, a prosthesis, an ostomy or stoma pouch, a buccal patch, or a transdermal patch. In some embodiments, the crosslinked layer of the polydiorganosiloxane composition may also be useful for other articles including dentures and hairpieces.

[0046] FIG. 4A and FIG 4B are top plan views of other articles (e.g. wound dressing) comprising a mask (e.g. substrate) frame 405 substantially surrounding a single opening comprising the crosslinked polydiorganosiloxane layer 420. In some embodiments, the mask (e.g. substrate) frame has a width “w” of 1 cm ranging up to 5, 10, 15, or 20 cm. In top plan view, the width is typically the smallest dimension of the mask (e.g. substrate) frame. In some embodiments, the mask utilized during manufacturing has a wider frame width that is cut to a smaller width after crosslinking of the polydiorganosiloxane composition. In FIG. 4A, the frame of the article is cut through the width. This facilitates removal of the underlying release liner. In FIG. 4B a portion of the frame has been removed to provide void 460 suitable for insertion of an intravenous (IV) tube.

[0047] FIG. 5 is a top plan view of another embodied mask 501 comprising a plurality of first major openings 510 suitable for the central wound-contact area of an individual medical article and second minor (e.g. circular) openings 560 suitable for insertion of an intravenous (IV) tube. In some embodiments, the surface area of the major opening is at least 5, 10, 15, or 20 times greater than the minor opening in top plan view.

[0048] FIG. 6 is a schematic side view of a layer of polydiorganosiloxane composition 620 disposed between a mask substrate 601 and release liner substrate 640. In this embodiment, the (e.g. polyurethane) mask substrate 501 may further comprise (e.g. paper) carrier substrate 615 to facilitate web handling of the highly conformable polyurethane film. The mask substrate 601 and carrier substrate 615 comprise one or more openings 610. The carrier substrate can be removed after crosslinking of the polydiorganosiloxane composition or at the time of use of the article.

[0049] FIG. 7 is a top plan of a (e.g. wound dressing) article prepared from the mask of FIG. 5. The article comprises a mask substrate frame 705 surrounding major opening 710. The crosslinked polydiorganosiloxane layer 720 is exposed through major opening 710. Second, (e.g. circular) minor opening 760 is suitable for insertion of an IV tube. In some embodiments, the crosslinked polydiorganosiloxane layer 720 is exposed through minor opening 760. In another embodiment, minor opening 760 may not be present in the mask, but instead is cut through all the layers after crosslinking of the polydiorganosiloxane layer.

[0050] FIG. 8 is a top plan view of another embodied mask comprising a plurality of openings 810 that form a stiffening system (i.e. the same stiffening systems as described with respect to FIG. 9A.

[0051] FIG. 9A is a top plan of a (e.g. wound dressing) article prepared from the mask of FIG. 8. The article comprises a mask (e.g. substrate) frame 905 surrounding the openings. The crosslinked polydiorganosiloxane layer 920 is exposed through the openings. Portions of the mask 971, 972, and 973 span from one side of the mask (e.g. substrate) frame 905A to the opposing side of the mask (e.g. substrate) frame 905B forming a stiffening system for the crosslinked polydiorganosiloxane layer 920. A portion of the frame 905 and crosslinked polydiorganosiloxane layer 920 has been removed to provide void 960 suitable for insertion of an intravenous (IV) tube.

[0052] FIG. 9B is a schematic side view of an article of 9A at the location of the dashed line of FIG 9A. In this embodiment, the crosslinked layer of polydiorganosiloxane comprises 920 comprises two different polydiorganosiloxane compositions 920 A and 920B as previously described, disposed between a mask (e.g. substrate) and release liner substrate (below first major surface 921 that is not shown). The mask comprises the mask (e.g. substrate) frame 905 and mask (e.g. substrate) stiffening element 973. During crosslinking, surface 923 (i.e. surface C) of layer 920B is exposed to the greatest dosage of radiant energy since it exposed by the openings of the mask and is closest to the source of radiant energy. First major surface 921 of layer 920B comprises two adjacent pressure sensitive adhesive surfaces, A and B. Surface A has different adhesive properties such as lower tack, lower elongation, and higher tensile strength than Surface B that is covered by the mask (e.g. substrate) 905 or 973 during crosslinking.

[0053] FIG. 10 is a top plan view of an article 1000 comprising a mask substrate frame 1005, a stiffening system comprising mask substrate stiffening elements 1071, 1072, and 1073 that span from one side of the mask substrate frame 1005A to the opposing side of the mask substrate frame 1005A, and a void 1060 in at least the mask substrate and typically all the layers suitable for insertion of a tube.

[0054] FIG. 11 is a top plan view of an article 1100 comprising a mask (e.g. substrate) frame 1105, a stiffening system comprising mask (e.g. substrate) stiffening elements 1071, 1072, and 1073 that span from one side of the mask (e.g. substrate) frame 1105A to the opposing side of the mask (e.g. substrate) frame 1105B, and an absorbent pad 1080 disposed between the release liner substrate and the crosslinked layer of polydiorganosiloxane 1120. When the crosslinked layer of polydiorganosiloxane 1120 is transparent, the underlying absorbent pad 1080 is visible through the crosslinked layer of polydiorganosiloxane 1020.

[0055] FIG. 12. is an exploded schematic view depicting the layers of another embodied article shown in part in FIG. 2 of US 7,294,752. In one embodiment, the article comprises a layer of polydiorganosiloxane composition 1220 disposed between a mask substrate 1201 and release liner substrate 1240. The mask substrate 1201 is absent at the location of the mask substrate opening(s). As previously described with respect to FIGs 3 and 9, during crosslinking, the portion of the layer of the polydiorganosiloxane composition that is exposed through the one or more openings of the mask is exposed to a greater dosage of radiant energy than the portion covered by the mask substrate. Thus, the portion of the layer of the polydiorganosiloxane composition that is exposed through the one or more openings of the mask has higher crosslinking and lower tack than the adjacent portion(s) of the layer of polydiorganosiloxane covered by mask substrate during crosslinking, as previously described. In some embodiments, the article further comprises a stiffening system 1270 between the mask substrate and crosslinked layer of layer of the polydiorganosiloxane composition, rather than a stiffening system that is integrated with an opening of the mask substrate. Such stiffening system can be made by various techniques such as described in US 7,294,752 and WO2020 / 245721; incorporated herein by reference.

[0056] Fig. 13 is a top plan view of another embodied article comprising the stiffening system of FIG. 11 integrated within the major opening of the mask substrate of the article of FIG. 12. This embodiment, may optionally further comprise a second a stiffening system 1270 between the mask substrate and crosslinked layer of the polydiorganosiloxane composition, as depicted in FIG. 12.

[0057] FIG. 14 is an exploded schematic view depicting the layers of another embodied article, suitable for use as a surgical drape or cover for a dressing of a negative-pressure therapy system as described in US2017 / 0079846; incorporated herein by reference. This article comprises a layer of polydiorganosiloxane composition 1420 disposed between a mask (e.g. substrate) 1401, comprising a plurality of openings 1410, and release liner substrate 1440. The portions of the crosslinked layer of the polydiorganosiloxane composition exposed through the openings in the mask substrate have greater crosslinking and typically lower tack than the adjacent portions covered by the mask substrate. The crosslinked layer of the polydiorganosiloxane composition may be characterized as a sealing adhesive. The article may optionally further comprise an (e.g. acrylic) bonding adhesive, as described in US2017 / 0079846.

[0058] Polydioganosiloxane Composition

[0059] Silicone gel materials have been used for medical therapies for promoting scar tissue healing. Lightly crosslinked silicone gels are soft, tacky, elastic materials that have low to moderate adhesive strength compared to traditional, tackified silicone PSAs. Silicone gels are typically softer than silicone PSAs, resulting in less discomfort when adhered to and removed from skin. The combination of relatively low adhesive strength and moderate tack make silicone gels suitable for gentle to skin adhesive applications.

[0060] Crosslinked siloxane networks can be formed from either functional or non-functional silicone materials. When the siloxane network is formed from a functional silicone material, the functional groups may react or in other words cure, which also may be characterized as crosslinking. These gel adhesives have excellent wetting characteristics, due to the very low glass transition temperature (Tg) and modulus of the poly siloxane network.

[0061] The silicone materials are polydiorganosiloxanes, i.e., materials comprising a polysiloxane backbone. In some embodiments, the nonfunctionalized silicone materials can be a linear material described by the following formula illustrating a siloxane backbone with aliphatic and / or aromatic substituents: wherein Rl, R2, R3, and R4 are independently selected from the group consisting of an alkyl group and an aryl group, each R5 is an alkyl group and n and m are integers, and at least one of m or n is not zero. In some embodiments, one or more of the alkyl or aryl groups may contain a halogen substituent, e.g., fluorine. For example, in some embodiments, one or more of the alkyl groups may be -CH2CH2C4F9.

[0062] In some embodiments, R5 is a methyl group, i.e., the nonfunctionalized polydiorganosiloxane material is terminated by trimethylsiloxy groups. In some embodiments, Rl and R2 are alkyl groups and n is zero, i.e., the material is a poly (dialkylsiloxane). In some embodiments, the alkyl group is a methyl group, i.e., poly(dimethylsiloxane) (“PDMS”). In some embodiments, Rl is an alkyl group, R2 is an aryl group, and n is zero, i.e., the material is a poly (alkylarylsiloxane). In some embodiments, Rl is methyl group and R2 is a phenyl group, i.e., the material is poly(methylphenylsiloxane). In some embodiments, Rl and R2 are alkyl groups and R3 and R4 are aryl groups, i.e., the material is a poly(dialkyldiarylsiloxane). In some embodiments, R1 and R2 are methyl groups, and R3 and R4 are phenyl groups, i.e., the material is poly(dimethyldiphenylsiloxane).

[0063] In some embodiments, the nonfunctionalized polydiorganosiloxane materials may be branched. For example, one or more of the Rl, R2, R3, and / or R4 groups may be a linear or branched siloxane with alkyl or aryl (including halogenated alkyl or aryl) substituents and terminal R5 groups.

[0064] As used herein, “nonfunctional groups” are either alkyl or aryl groups consisting of carbon, hydrogen, and in some embodiments, halogen (e.g., fluorine) atoms. As used herein, a “nonfunctionalized polydiorganosiloxane material” is one in which the Rl, R2, R3, R4, and R5 groups are nonfunctional groups.

[0065] Generally, functional silicone systems include specific reactive groups attached to the polysiloxane backbone of the starting material (for example, hydrogen, hydroxyl, vinyl, allyl, or acrylic groups). As used herein, a “functionalized polydiorganosiloxane material” is one in which at least one of the R-groups of Formula 2 is a functional group.

[0066] R R R R

[0067] R— s | i-o+ L s | i-o Jm-L | i-o Jn-s | i-R(2)R R R R

[0068] In some embodiments, a functional polydiorganosiloxane material comprises at least two R-groups that are functional groups. Generally, the R-groups of Formula 2 may be independently selected. In some embodiments, at least one functional group such as hydride group, a hydroxy group, an alkoxy group, a vinyl group, an epoxy group, and an acrylate group. When the polydiorganosiloxane is nonfunctionalized polydiorganosiloxane, the polydiorganosiloxane lack functional groups.

[0069] In addition to functional R-groups, the R-groups may be nonfunctional groups, e.g., alkyl or aryl groups, including halogenated (e.g., fluorinated) alky and aryl groups. In some embodiments, the functionalized polydiorganosiloxane materials may be branched. For example, one or more of the R groups may be a linear or branched siloxane with functional and / or non-functional substituents.

[0070] The polydiorganosiloxanes (e.g. polydimethylsiloxanes PDMS) may be oils, fluids, gums, elastomers, or resins, e.g., friable solid resins. Lower molecular weight, lower viscosity materials are referred to as fluids or oils, while higher molecular weight, higher viscosity materials are referred to as gums; however, there is no sharp distinction between these terms. Silicone oils are commercially available (e.g. from Wacker) at viscosities from 0.65 to 1,000,000 mPa* sec at 25 °C. In typical embodiments, higher viscosity (e.g. non-functional) liquid polydiorganosiloxanes are preferred. In some embodiments, the liquid polydiorganosiloxane has a viscosity of at least 25,000; 50,000; 100,000; 250,000; 500,000; 750,000, or 1,000,000 mPa*sec at 25 °C. Higher viscosity, which is also indicative of higher molecular weight, can be preferred. When polydiorganosiloxane gum is utilized, the viscosity may be greater than 1,000,000 mPa*sec at 25 °C. The gentle to skin adhesives are prepared by combining one or more polydiorganosiloxane materials (e.g., silicone oils or fluids), optionally with an appropriate tackifying resin, coating the resulting combination, and crosslinking using radiation, typically electron beam (E-beam) or gamma irradiation. Generally, any known additives useful in the formulation of adhesives may also be included.

[0071] In some embodiments, silicate tackifying resins may be used. In some exemplary adhesive compositions, a plurality of silicate tackifying resins can be used to achieve desired performance.

[0072] Suitable silicate tackifying resins include those resins composed of the following structural units M (i.e., monovalent R^SiO 3 / 2 units), D (i.e., divalent R'2SiO2 / 2 units), T (i.e., trivalent R'SiC>3 / 2 units), and Q (i.e., quaternary SiOq / 2 units), and combinations thereof. Typical exemplary silicate resins include MQ silicate tackifying resins, MQD silicate tackifying resins, and MQT silicate tackifying resins. These silicate tackifying resins usually have a number average molecular weight in the range of 100 to 50,000- gm / mole, e.g., 500 to 15,000 gm / mole and generally R' groups are methyl groups.

[0073] MQ silicate tackifying resins are copolymeric resins where each M unit is bonded to a Q unit, and each Q unit is bonded to at least one other Q unit. Some of the Q units are bonded to only other Q units. However, some Q units are bonded to hydroxyl radicals resulting in HOSiC>3 / 2 units (i.e., "TOH"units), thereby accounting for some silicon-bonded hydroxyl content of the silicate tackifying resin.

[0074] The amount of silicon bonded hydroxyl groups (i.e., silanol) on the MQ resin may be reduced to no greater than 1.5 weight percent, no greater than 1.2 weight percent, no greater than 1.0 weight percent, or no greater than 0.8 weight percent based on the weight of the silicate tackifying resin. This may be accomplished, for example, by reacting hexamethyldisilazane with the silicate tackifying resin. Such a reaction may be catalyzed, for example, with trifluoroacetic acid. Alternatively, trimethylchlorosilane or trimethylsilylacetamide may be reacted with the silicate tackifying resin, a catalyst not being necessary in this case.

[0075] MQD silicone tackifying resins are terpolymers having M, Q and D units. In some embodiments, some of the methyl R' groups of the D units can be replaced with vinyl (CH2=CH-) groups ("D^1" units). MQT silicate tackifying resins are terpolymers having M, Q and T units.

[0076] Suitable silicate tackifying resins are commercially available from sources such as Dow Corning (e.g., DC 2-7066), Momentive Performance Materials (e.g., SR545 and SR1000), and Wacker Chemie AG (e.g., BELSIL TMS-803).

[0077] In some embodiments, the layer of polydiorganosiloxane composition comprises (e.g. silicate) tackifying resin in an amount of at least 5, 6, 7, 8, 9, or 10 wt.% of the total polydiorganosiloxane composition. In some embodiments, the amount of (e.g. silicate) tackifying resin is not greater than 20, 25 or fO wt.%. In some embodiments, the polydiorganosiloxane composition may include any of a variety of known fillers (e.g. siliceous fillers, such as fumed silica) and additives including, but not limited to, pigments, additives for improving adhesion, additives for improving moisture-vapor transmission rate, antimicrobial agents (e.g. silver materials), pharmaceutical agents, cosmetic agents, natural extracts, silicone waxes, silicone polyethers, hydrophilic polymers and rheology modifiers. Hydrophilic additives used to improve adhesion, particularly to wet surfaces, include polymers such as poly (ethylene oxide) polymers, polypropylene oxide) polymers and copolymers of polyethylene oxide and propylene oxide), acrylic acid polymers, hydroxyethyl cellulose polymers, carboxyethyl cellulose, silicone polyether copolymers, such as copolymers of polyethylene oxide) and polydiorganosiloxane and copolymers of polypropylene oxide) and polydiorganosiloxane, and blends thereof. The polydiorganosiloxane composition may comprise various combinations of additives.

[0078] In some embodiments, the polydiorgansiloxane composition comprises fillers and / or additives in amounts up to 10, 15, 20, 25, or 30 wt.% of the total polydiorganosiloxane composition. In other embodiments, the polydiorgansiloxane composition comprises less than 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 wt.% of fillers and / or additives.

[0079] The poly siloxane material, the tackifying resin, if present, and any optional additives may be combined by any of a wide variety of known means prior to being coated and crosslinked. For example, in some embodiments, the various components may be pre-blended using common equipment such as mixers, blenders, mills, extmders, and the like.

[0080] In some embodiments, the materials may be dissolved in a solvent, coated, and dried prior to crosslinking. In some embodiments, solventless compounding and coating processes may be used. In some embodiments, solventless coating may occur at about room temperature. For example, in some embodiments, the materials may have kinematic viscosity of no greater than 100,000 centistokes (cSt), e.g., no greater than 50,000 cSt. However, in some embodiments, hot melt coating processes such as extrusion may be used, e.g., to reduce the viscosity of higher molecular weight materials to values more suitable for coating. The various components may be added together, in various combinations or individually, through one or more separate ports of an extruder, blended (e.g., melt mixed) within the extruder, and extruded to form the hot melt coated composition.

[0081] Physical Properties of the Crosslinked Polydiorganosiloxane Composition

[0082] In some embodiments, the portions of pressure sensitive adhesive of the first major surface that are exposed through the opening(s) of the mask substrate have a tack of at least 5. 10, 15, 20, 25, 30, 40, 45, 50, 55, 60, 65, 70, 75, or 80 grams force. The portions of pressure sensitive adhesive of the first major surface that are covered by the mask substrate typically have greater tack than the portions that are exposed through the opening(s) of the mask substrate. The difference in tack may be at least 25, 50, 75, 100, 150 grams force or greater. In some embodiments, the portions of pressure sensitive adhesive of the first major surface that are covered by the mask substrate have a tack of at least 50, 55, 60, 65, 70, 75, or 80 grams force. In some embodiments, the portion(s) of pressure sensitive adhesive of the first major surface that are covered by the mask substrate has a tack no greater than 300, 250, 200 or 150 grams force. In some embodiments, the portion of pressure sensitive adhesive of the first major surface that are covered by the mask substrate has a tack no greater than 120, 110, or 100 grams force.

[0083] In some embodiments, the film backing surface (e.g. that contact the wound) of the second major surface has a tack of less than 50, 45, 40, 35, 30, 25, 20, 15, or 10 grams force.

[0084] In some embodiments, the crosslinked polydiorganosiloxane layer has a tensile modulus of at least 0.10, 0.15, or 0.2 N / inch (2.54 cm). In some embodiments, the crosslinked polydiorganosiloxane layer has a tensile modulus of no greater than 0.4, 0.3, or 0.2 N / inch. In some embodiments, the crosslinked polydiorganosiloxane layer has a maximum tensile strength of at least 1, 1.5, 2, or 2.5 N / inch (2.54 cm). In some embodiments, the crosslinked polydiorganosiloxane layer has a maximum tensile strength of no greater than 4, 4.5, 3, 3.5, or 0.2 N / inch. In some embodiments, the crosslinked polydiorganosiloxane layer has a maximum elongation of at least 100, 150, 200, or 350%. In some embodiments, the crosslinked polydiorganosiloxane layer has a maximum elongation of no greater than 500, 400, or 300%. Tensile and elongation can be measured according to EN ISO 527-3 using a ZwickRoell Z010 machine equipped with a 500N loadcell. (Machine settings: Jaw separation: 50mm, test speed: lOOmm / min, preload: 0. IN.) Samples can be cut to a size of 80mm x linch, and tabs of 1 inch length on each side placed in the jaws for running the test. Tensile and elongation data for e-beam crosslinked polydiorganosiloxane compositions is reported in cofiled US Application No. 63 / 595884; incorporated herein by reference,

[0085] The peel adhesion to biological substrates such as human skin is known to be highly variable. Skin type, location on the body, and other factors can affect results. Generally, average values of peel adhesion from skin are subject to large standard deviations. In some embodiments, the average peel adhesion for human skin may be less than 200 gm / 2.54 cm, and in some embodiments, less than 100 gm / 2.54 cm.

[0086] Additional Components

[0087] The (e.g. medical) adhesive article may comprise various additional components as known in the art. Such additional components are optional with respect to the broadest embodiments of the invention, yet may be preferred for some medical articles.

[0088] In some embodiments, the crosslinked layer of the polydiorganosiloxane composition may further comprise a porous reinforcement layer such as a fibrous web, apertured film, or scrim. The fibrous web may be nonwoven, woven or knit. When present, such porous reinforcement layer is typically embedded within the crosslinked layer of the polydiorganosiloxane composition. This is typically accomplished by applying a first layer of polydiorganosiloxane composition to a (e.g. release liner) substrate, applying the porous reinforcement layer to the first layer, and then applying a second layer of the polydiorganosiloxane composition to the reinforcement layer. Alternatively, the porous reinforcement layer may be applied to the release liner, prior to applying the layer of the polydioorganosiloxane composition.

[0089] In some embodiments, when the adhesive article is a wound dressing, the article may further comprise an absorbent pad, such as described in US2019 / 0231604; incorporated herein by reference.

[0090] The absorbent pad is typically disposed at a central portion of the pressure sensitive adhesive surface, such that there is adhesive on opposing sides or the pressure sensitive adhesive surrounds the absorbent pad.

[0091] The absorbent pad can be made of one or more layers, and each layer can be made of one or more absorbent materials. Preferred absorbent pads are relatively flexible. Flexibility allows for a medical article incorporating the absorbent pad to be easily applied to a bendable portion of a body, such as a joint, etc. The absorbent pad can be slit at one of more locations to provide additional flexibility. In some embodiments, the absorbent pad may be translucent or transparent, thus allowing for visual inspection of the wound without removal of the wound dressing.

[0092] The absorbent pad can be made of synthetic or natural materials and may include, but is not limited to, woven or nonwoven materials (e.g., woven or nonwoven cotton or rayon), hydrocolloids (e.g., pectin, gelatin, carboxymethylcellulose(CMC), cross-linked carboxymethylcellulose (X-link CMC), cross-linked polyacrylic acid(PAA) and the hydrocolloids described in U.S. Pat. Nos. 5,622,711 and 5,633,010), polymer gels (e.g., hydrogels), foams, collagens, hydrofibers, alginates, and combinations thereof. In some embodiments, the absorbent pad may include a polymeric fabric, a polymeric foam, and combinations thereof. For example, the polymeric fabric may be a nonwoven and the polymeric foam may be the foam used in the TEGADERM foam adhesive dressing available from 3M Company, St. Paul, Minn. In certain embodiments, the polymeric foam is a polymethane foam.

[0093] The absorbent pad may optionally include other components, including one or more active agents, such as pharmacologically active agents, as further described in US2019 / 0231604.

[0094] The presence of a porous organic polymer substrate such as a (e.g. nonwoven, apertured film) mask substrate can provide reinforcement, improved web handling, and greater (e.g. tensile, tear) strength to the crosslinked polydiorganosiloxane layer. The article may optionally further comprise a porous organic polymer substrate on the first major surface, proximate the release liner or embedded within the crosslinked polydiorganosiloxane layer, such as described in cofded US Application No. 63 / 595859; incorporated herein by reference.

[0095] In some embodiments, the article may optionally further comprise a plurality of apertures that extend through the crosslinked layer of the polydiorganosiloxane adhesive composition. Further, the article may optionally further comprise a plurality of apertures that extend through the mask substrate and underlying crosslinked layer of the polydiorganosiloxane adhesive composition. The invention is further illustrated by the following non-limiting examples.

[0096] Examples

[0097] Materials Used in the Examples

[0098] Test Method:

[0099] Tack Test. Tack (force of removal) was measured using a TA-XT Plus Texture Analyzer equipped with a 5kg load cell and a 7 mm stainless steel cylinder probe. The test sample was slit to a width of 1 inch and laminated to a brass bar with 10 mm diameter holes through it to allow for the probe to reach the adhesive face of the tape. The probe head was cleaned with n-heptane after each measurement. Test parameters: Pretest speed: 1.0 mm / sec, test speed: 0.05 mm / sec, applied force: 5 grams, contact time: 5 seconds, trigger force: 60 grams, and withdraw distance: 12 mm. Data represents the average value of three measurements per example.

[0100] Sample preparation

[0101] Silicone Oil and Silicone Tackifying Resin were homogeneously mixed at a weight ratio of 70 / 30 in a 100g batch size using a SpeedMixer® DAC150 (Hauschild GmbH, Germany) to obtain a silicone composition for coating. The silicone composition was coated onto a 50 micron polyethylene terephthalate film comprising a release coating at the thickness specified in Table 1 using a knife coater followed by exposure to e-beam radiation having an acceleration voltage of 280kV using a CB-300 electron beam generating apparatus available from Energy Sciences, Inc. (Wilmington, MA) to provide the dosage specified in Table 1 to form Layer 1.

[0102] For Examples 2 and 3, the first e-beam step was skipped. A second layer of silicone oil (i.e. without silicone tackifying resin) was coated onto Layer 1 at the thickness specified in Table 1 to form Layer 2. A mask material was laminated onto Layer 2, followed by exposure to e-beam radiation having an acceleration voltage of 280kV using a CB-300 electron beam generating apparatus available from Energy Sciences, Inc. (Wilmington, MA) to provide the dosage specified in Table 1. For Examples 1-3, the mask material was the nonwoven mask material described above. For Example 4, the mask material was the film mask material described above. The mask shape is specified in Table 1. The thickness of Layer 1 and the thickness of Layer 2 are described in Table 1.

[0103] Table 1

[0104] Table 2: Tack Test Results

[0105] With respect to FIG. 9B, surface A is the unmasked crosslinked PSA. Surface B is the masked crosslinked PSA. Higher tack is obtained at Surface B due to the mask blocking some of the radiation exposure. Surface C is the crosslinked opposing surface of silicone oil. Surface C has lower tack than Surface A because surface C is exposed to a higher dosage of e-beam radiation and because surface C comprises a polydiorganosiloxane composition that lacks tackifying resin.

[0106] Since Ex. 3-4 have the same materials, thickness, and e-beam crosslinking dosage as Ex-2, the tack is expected to be the same as Ex-2.

Claims

What is claimed is:

1. A method of making an adhesive article comprising: a) providing a mask between a layer of a polydiorganosiloxane composition and a source of radiant energy, wherein the mask comprises one or more openings that exposes a portion of the layer of polydiorganosiloxane composition covers a portion of the layer of polydiorganosiloxane composition; b) crosslinking the layer of the polydiorganosiloxane composition with radiation such that the portion of the layer of polydiorganosiloxane composition exposed through the one or more openings of the mask has greater crosslinking than the portion covered by the mask.

2. The method of claim 1 wherein the layer of polydiorganosiloxane composition comprises a first major surface proximate the substrate that forms a pressure sensitive adhesive and an opposing second major surface proximate the mask and opening(s) thereof that forms a fdm backing.

3. The method of claim 2 wherein the first major surface of the layer of polydiorganosiloxane composition is disposed on a release liner.

4. The method of claim 2-3 wherein after crosslinking the pressure sensitive adhesive portion of the first major surface covered by the mask has a tack of at least 50, 60, 70, 80, 90, or 100 grams force and the pressure sensitive adhesive portion of the first major surface exposed by the mask has tack lower than the covered portion.

5. The method of claim 3 wherein after crosslinking the film backing of the opening(s) of the mask substrate has a tack of less than 50, 45, 40, 35, 30, 25, 20, 15, or 10.

6. The method of claims 1-5 wherein the mask comprises a porous substrate including woven or nonwoven fabric or an organic polymeric film including polymethane, or a combination thereof.

7. The method of claims 1-6 wherein the mask is i) a mask substrate that is permanently bonded to the layer of polydiorganosiloxane after crosslinking; ii) a release liner mask that may be removed from the layer of polydiorganosiloxane after crosslinking; iii) a non-contact processing mask; or a combination thereof.

8. The method of claims 1-7 wherein the mask comprises a plurality of major openings substantially surrounded by a frame of the mask9. The method of claim 8 wherein i) the frame of the mask further comprises a void suitably sized for insertion of an intravenous tube; or ii) the mask further comprise a plurality of minor openings suitably sized for insertion of an intravenous tube.

10. The method of claims 1-9 wherein the openings of the mask form a stiffening system or a stiffening system is provided between the mask substrate and the layer of the polydiorganosiloxane composition.

11. The method of claims 1-10 wherein the layer of the polydiorganosiloxane composition comprises a single layer or multiple layers of the same or different polydiorganosiloxane compositions.

12. The method of claim 1-11 wherein the layer of polydiorganosiloxane composition comprises a first layer proximate the (e.g. release liner) substrate wherein the polydiorganosiloxane composition comprises (e.g. silicate) tackifying resin, and a second layer proximate the mask that comprises less or no (e.g. silicate) tackifying resin.. f3. The method of claims 1-12 wherein the total thickness of the layer(s) of polydiorganosiloxane composition is at least 200, 250, 300, 350, 400, 450, or 500 microns.

14. The method of claims 1-13 further comprising an absorbent pad disposed between the film backing and the layer of polydiorganosiloxane composition.

15. An adhesive article comprising: a layer of a crosslinked polydiorganosiloxane composition having two major surfaces, a first major surface comprising a pressure sensitive adhesive and a second major surface bonded to a mask substrate comprising at least one opening that exposes a film backing of the crosslinked polydiorganosiloxane composition.

16. An adhesive article comprising: a layer of a crosslinked polydiorganosiloxane composition having two major surfaces, a first major surface comprising a pressure sensitive adhesive and a second major surface bonded to a mask substrate; wherein the first major surface comprises a portion covered by the mask substrate and a portion exposed through openings of the mask substrate and the exposed portion comprise greater crosslinking than the covered portions.

17. An adhesive article comprising: a layer of a crosslinked polydiorganosiloxane composition having two major surfaces, a first major surface comprising a pressure sensitive adhesive and a second major surface comprising a film backing wherein the first major surface comprises a first portion comprising greater crosslinking than adjacent an portion.

18. The adhesive article of claim 17 wherein the first portion is a central (e.g. wound contact) portion and the second portion is a frame (e.g. skin contact) portion.

19. The adhesive article of claims 15-17 further characterized by claims 2-14.

20. The adhesive article of claims 15-19 for use as a medical article.

21. The adhesive article of claims 15-20 wherein the article is a medical tape, bandage, wound dressing.

22. A method of use for an adhesive article comprising providing the article of claims 15-21 and contacting the pressure sensitive adhesive to skin or a wound.

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