WO2025094158A1

WO2025094158A1 - Polydiorganosiloxane composition comprising an antimicrobial, articles, and methods

Info

Publication number: WO2025094158A1
Application number: PCT/IB2024/060878
Authority: WO
Inventors: Christoph T. R. SCHUELL; Hironobu Ishiwatari; Kiu-Yuen Tse; Leon M. DEAN; Joseph J. Stoffel
Original assignee: Solventum Intellectual Properties Co
Current assignee: Solventum Intellectual Properties Co
Priority date: 2023-11-03
Filing date: 2024-11-04
Publication date: 2025-05-08
Anticipated expiration: 2026-05-03

Abstract

A composition is described comprising polydiorganosiloxane; a silver material; and at least 1 wt.% of an oxygen-bearing metal filler of silicone, titanium, zirconium, or combination thereof. The crosslinked composition can have higher tensile strength than the same composition without the oxygen-bearing metal filler. In some embodiments, the polydiorganosiloxane comprises a nonfunctional polydiorganosiloxane. In another embodiment, a method of making an adhesive article is described comprising providing a layer of a polydiorganosiloxane composition on a (e.g. release liner) substrate wherein the layer comprises nonfunctionalized polydiorganosiloxane and a silver material; and exposing the layer of polydiorganosiloxane composition to radiation thereby crosslinking the layer of the polydiorganosiloxane composition.

Description

POLYDIORGANOSILOXANE COMPOSITION COMPRISING AN ANTIMICROBIAL, ARTICLES, AND METHODS

Summary

In one embodiment, a composition is described comprising polydiorganosiloxane; a silver material; and at least 1 wt.% of an oxygen-bearing metal filler of silicone, titanium, zirconium, or combination thereof. The (e.g. e-beam) crosslinked composition can have higher tensile strength than the same composition without the oxygen-bearing metal filler. In some embodiments, the polydiorganosiloxane comprises a nonfunctional polydiorganosiloxane.

In another embodiment, a method of making an adhesive article is described comprising: a) providing a layer of a polydiorganosiloxane composition on a substrate wherein the layer comprises nonfunctionalized polydiorganosiloxane and a silver material; and b) exposing the layer of polydiorganosiloxane composition to radiation thereby crosslinking the layer of the polydiorganosiloxane composition. The substrate is typically a release liner. In one embodiment, a first layer of a polydiorganosiloxane composition with a silver material is disposed on the substrate and a second layer of a polydiorganosiloxane composition lacking a silver material is provided on the first layer. In another embodiment, the first layer comprises (e.g. silicate) tackifying resin and the second layer lacks (e.g. silicate) tackifying resin.

Also described are adhesive article comprising a layer of crosslinked polydiorganosiloxane compositions) as described herein.

In some embodiments, the adhesive article is a medical article, such as medical tape, bandage, dressing, or compression wrap.

In some embodiments, the adhesive articles described herein are suitable for use as a medical article.

Also described is a method of use for an adhesive article comprising providing an adhesive article as described herein and contacting (e.g. the first major surface) to skin or a wound.

Brief Description of the Drawings

FIG. 1 is a schematic side view of an adhesive article comprising a crosslinked polydiorganosiloxane layer on a release liner;

FIG. 2 is a schematic side view of an adhesive article comprising a crosslinked multi-layer polydiorganosiloxane layer on a release liner;

FIG. 3-5 are schematic side view of adhesive articles comprising a crosslinked polydiorganosiloxane layer and a porous substrate on a release liner; Written Description

Adhesive Articles

With reference to FIG. 1 in one embodiment, the adhesive article 10 comprises a crosslinked polydiorganosiloxane layer (120A) proximate a (e.g. release liner) substrate (140). In another embodiments, depicted in FIG. 2, the adhesive article 50 comprises a first crosslinked polydiorganosiloxane layer (120A) proximate a (e.g. release liner) substrate (140) and a second crosslinked polydiorganosiloxane layer (120B) disposed on the a first crosslinked polydiorganosiloxane layer (120 A). With reference to FIGs. 3-5, the layer of crosslinker polydiorganosiloxane composition may further comprise a porous substrate (180, 280, 380).

The layer of polydiorganosiloxane composition has a first major surface (121, 221, 321) proximate the release liner support (140, 240, 340) and an opposing second major surface (123, 223, 323). The major surfaces are typically parallel to each other. The thickness of the layer(s) is the distance in the direction orthogonal to the major surfaces. In some embodiment, the first major surface is a pressure sensitive adhesive and the second opposing major surface is a film backing.

In some embodiments, a second release liner is in contact with film backing surface.

In another embodiment, an adhesive (e.g. tape) article may comprise the crosslinked layer of a polydiorganosiloxane composition in the absence of release liners. The adhesive (e.g. tape) article is wound upon itself in a roll such that backing surface is in contact with pressure sensitive adhesive surface.

In some embodiments, the crosslinked layer of the polydiorganosiloxane composition is suitable for medical articles such as 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.

In some embodiments, the crosslinked layer of the polydiorganosiloxane composition is suitable for contact to skin or other tissue of humans and/or animals.

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. Crosslinked siloxane networks can be formed from either functional or non-functional silicone materials. However, in some embodiments, non-functional polydiorganosiloxane(s) are preferred. 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 polysiloxane network.

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.

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, Rl and R2 are methyl groups, and R3 and R4 are phenyl groups, i.e., the material is poly(dimethyldiphenylsiloxane).

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.

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. 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.

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 non-functional polydiorganosiloxane, the polydiorganosiloxane lacks such functional groups.

In addition to functional R-groups, some of 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 poly diorganosiloxane 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.

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 50,000; 100,000; 250,000; 500,000; 750,000; or 1,000,000 mPa*sec at 25 °C. 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.

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.

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'SiO3/2 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.

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" _unit_s), thereby accounting for some silicon-bonded hydroxyl content of the silicate tackifying resin.

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.

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.

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).

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 amount of (e.g. silicate) tackifying resin is less than 5, 4, 3, 2, or 1 wt.% (e.g. zero).

In some embodiments, the layer of polydiorganosiloxane composition comprises more than layer. For example, a first layer may be disposed on the (e.g. release liner) substrate and second layer may be disposed on the first layer. In this embodiment, the first polydiorganosiloxane layer may comprise (e.g. silicate) tackifying resin in the amount described; whereas the second polydiorganosiloxane layer may comprise no (e.g. silicate) tackifying resin or less (e.g. silicate) tackifying resin than the first polydiorganosiloxane layer.

In some embodiments, the polydiorganosiloxane composition may include any of a variety of other known fillers and additives including, but not limited to, fillers pigments, additives for improving adhesion, additives for improving moisture-vapor transmission rate, antimicrobial agents, pharmaceutical agents, cosmetic agents, natural extracts, silicone waxes, silicone polyethers, hydrophilic polymers and rheology modifiers. Additives used to improve adhesion, particularly to wet surfaces, include polymers such as polyethylene oxide) polymers, polypropylene oxide) polymers and copolymers of polyethylene oxide) and polypropylene oxide), acrylic acid polymers, hydroxyethyl cellulose polymers, silicone polyether copolymers, such as copolymers of polyethylene oxide) and polydiorganosiloxane and copolymers of polypropylene oxide) and polydiorganosiloxane, and blends thereof.

In some embodiments, the polydiorgansiloxane composition comprises other 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 other additives.

The polysiloxane material, the antimicrobial (e.g. silver material) the tackifying resin, if present, and any optional components 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, extruders, and the like.

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.

Silver Compound

The wound contact layer (e.g. of the first major surface) further comprises a silver material, such as silver particles, ionic silver, and silver salts, for providing antimicrobial and/or bacteriostatic properties. The silver material may be distributed throughout, as well as on the surface of, the wound contact layer. For example, in some embodiments, the silver material may include silver acetate, which may be added to the silicone composition. In some embodiments, the silver material may include other silver compounds, such as silver orthophosphate, silver sulfate, silver sodium hydrogen zirconium phosphate, silver lactate, silver-oxidized regenerated cellulose, silver chloride.

In some embodiments, the silver material may be a sparingly soluble silver compound that provides sustained release of silver ions over time based in part on their limited solubility and inherent dissociation equilibrium constants. Silver compounds useful in the present invention include silver oxide, silver sulfate, silver acetate, silver chloride, silver lactate, silver phosphate, silver sulfadiazine, silver stearate, silver thiocyanate and silver carbonate.

In some embodiments, a higher valency silver oxide, i.e., where the oxidation state of silver is Ag (II), or Ag(III), can be used, as described in W02005/056067

Combination of different silver containing particles can be utilized.

Typically the silver material is dispersed within the polydiorganosiloxane composition. In some embodiments, the polydiorganosiloxane composition comprises silver material(s) in an amount of at least 1, 2, 3, 4, or 5 wt.% based on the total weight of the poly diorgansilo xane composition. The silver materials is typically no greater than 10, 9, 8, 7, 6. or 5 wt.%.

In another embodiment, a porous (e.g. mesh) substrate may be coated with a silver material such as described in W02005/056067; incorporated herein by reference. In this embodiment, the porous substrate may comprise no greater than 10 or 5 mg/cm² of silver (e.g. compound) material. The amount of silver (e.g. compound) material may range from 0.1 to 2 mg/cm². The silver coated porous (e.g. mesh) substrate is then incorporated into the layer of polydiorganosiloxane composition. In this embodiment, the polydiorganosiloxane composition may lack silver material.

Oxygen-bearing Metal Filler

In some embodiments, the polydiorganosiloxane composition comprises a (e.g. biocompatible) oxygen-bearing metal filler. Typically the metal is silicon, titanium, or zirconium. The covalently bonded oxygen-bearing groups are typically oxide or hydroxyl.

In one embodiments, the oxygen-bearing metal filler is silicic acid, chemical compounds containing the element silicon attached to oxide (=0) and hydroxyl ( -OH) groups, with the general formula [H2_XSiO_x+2]n or [SiO_x(OH)_4-2x]n. A representative formula is depicted as follows:

Similarly, titanic acid is chemical compounds with the general formula [TiO_x(OH)_4-2x]n. Further, acids of zirconium analogous to silicic acid are known in its salts (i.e. zirconates).

In some embodiments, oxygen-bearing silicon fillers are preferred. Other oxygen-bearing silicon fillers include for example precipitated silica (i.e. an amorphous form of silica (silicon dioxide, SiO2); as well as fumed silica, also known as pyrogenic silica.

Oxygen-bearing silicon fillers are commercially available. Precipitated silicic acid is available from Sigma Aldrich Chemie GmbH (Taufkirchen, Germany), pyrogenic silica is available under the trade designation HDK® from Wacker Chemie AG (Burghausen, Germany), and pyrogenic silica is available under the trade designation Aerosil® from Evonik Industries AG (Essen, Germany). In some embodiments, the polydiorgansiloxane composition comprises at least 1, 2, 3, 4, or wt.% of oxygen-bearing metal (e.g. silicon) fillers based on the total weight of the polydiorgansiloxane composition. The amount of oxygen-bearing metal (e.g. silicon) fillers is typically no greater than 30, 25, 20, 15, or 10 wt.%.

Hydrophilic Component

In some embodiments, the polydiorgansiloxane composition comprises a hydrophilic component, typically dispersed in the silicone gel. The hydrophilic component can absorb moisture aides.

In some embodiments, the hydrophilic component is a carbohydrate having at least 3 hydroxyl groups, or a derivative thereof. Examples include saccharides, (e.g. monosaccharides, disaccharides, trisaccharides, polysaccharides) as well as naturally occurring polysaccharides (e.g., sodium carboxymethylcellulose) and other modified cellulose derivatives (e.g., cellulose ethyl ether; cellulose ethyl hydroxyethyl ether; cellulose hydroxyethyl ether; cellulose methyl hydroxyethyl ether), aliginic acid, sodium alginate, guar gum; pullulan, pectin, arabic gum, and similar materials derived from carrageenans (from seaweed), pectins (from plant extracts) and xanthan (from microbial fermentation process). Of the ionic carbohydrate polymers, sodium alginate and carboxymethyl cellulose are typically preferred.

The polydiorgansiloxane composition may comprise various combinations of hydrophilic components.

In some embodiments, the polydiorgansiloxane composition comprises at least 5, 6, 7, 8, 9, or 10 wt.% of hydrophilic component (e.g. carboxymethyl cellulose) based on the total weight of the polydiorgansiloxane composition. The amount of hydrophilic component is typically no greater than 50, 40, or 30 wt.% and in some embodiments no greater than 25, 20, 15, or 10 wt.%.

Method of Making

The method of making an adhesive article generally comprises providing a layer of a (e.g. uncrosslinked or partially crosslinked) poly diorgano siloxane composition on a substrate. The layer has a first major surface proximate the substrate and an opposing second major surface. The method comprises exposing the opposing second major surface of the layer of the polydiorganosiloxane composition to radiation thereby crosslinking the layer of the polydiorganosiloxane composition.

In some embodiments, the substrate is a support film, such as a polyester terephthalate support film. In typical embodiments, the substrate is a (e.g. first) release liner.

In some embodiments, the uncrosslinked polydiorganosiloxane composition may be applied to one release liner, with no substrate on the opposite surface (“open face”). Generally, the chamber is inerted (e.g., the oxygen-containing room air is replaced with an inert gas, e.g., nitrogen) while the samples are e-beam crosslinked, particularly when open-face crosslinking. However, the polydiorganosiloxane composition may be exposed to more than one pass of radiation or (e.g. different intensities of) radiation from both sides.

In some embodiments, the polydiorganosiloxane composition is crosslinked while in contact with a first release liner. After crosslinking, the pressure sensitive adhesive surface is contacted with a second release liner and the first release liner is removed. In some embodiments, the method further comprises winding the crosslinked layer of the polydiorganosiloxane composition into a roll (e.g. tape).

Various release liners are known and commercially available. The release liners may comprise a polyester terephthalate support film and a release coating. In some embodiments, the release coating may be a fluorosilicone material. Release coatings that are free of silicone materials and/or fluorinated materials have also been described for use with polydiorganosiloxane adhesive.

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 lOlbf 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).

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.

In typical embodiments, a thicker layer of the same polydiorganosiloxane composition is crosslinked from one side providing a crosslink gradient wherein one surface (i.e. the first major surface in contact with release liner) is a pressure sensitive adhesive and the opposing surface (i.e. closest to the source of radiation during curing) is a film backing. However, it is also contemplated that the polydiorganosiloxane layer may be formed by coating more than one layer of the same or different polydiorganosiloxane composition.

For example, in one embodiment, a first layer of a polydiorganosiloxane composition with a silver material is disposed on the (e.g. release liner) substrate and a second layer of a the polydioroganosiloxane composition lacking a silver material is provided on the first layer. In one embodiment, the first layer of polydiorganosiloxane composition further comprising tackifying resin; wherein the second layer comprises little or no tackifying resin. In yet another embodiment, the first layer comprises a silver material and a tackifying resin; whereas the second layer lacks both a silver material and a tackifying resin. In some embodiments, the first layer may have a thickness of at least 25, 50, or 100 microns. In some embodiments, the first layer may have a thickness of no greater than 250, 200, 150, 100, or 50 microns.

The thickness and crosslinking conditions can be selected such that the first major surface (proximate the substrate) forms a pressure sensitive adhesive and the opposing second major surface (closer to the radiant energy source) forms a film backing. When the opposing surface of the crosslinked polydiorganosiloxane composition is a film backing, the article may lack other fdm backing materials such as polyurethane film backings.

The 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.

In some embodiments, the polydiorganosiloxane composition may be 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. In some embodiments, such equipment may be used to crosslink, or partially crosslink the gentle to skin adhesives of the present disclosure. In some embodiments, such crosslinking may occur simultaneously with a sterilization process for a semi-finished or finished product, for example a tape or wound dressing.

In some embodiments, the polydiorganoxiloxane material is exposed to E-beam radiation having a voltage of at least 200, 250, 280, 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.

Physical Properties of the Crosslinked Polydiorganosiloxane Composition In some embodiments, the pressure sensitive adhesive of the first major surface has a tack of at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 grams force. In some embodiments, the pressure sensitive adhesive of the first major surface has a tack no greater than 120, 110, or 100 grams force. In some embodiments, the pressure sensitive adhesive of the first major surface has a tack no greater than 75, 50, or 25 grams force. In some embodiments, the pressure sensitive adhesive of the first major surface has a tack no greater than 15, 10, or 5 grams force.

In some embodiments, the film backing of the second major surface has a tack of less than 30, 25, 20, 15, 10, or 5 grams force.

In some embodiments, the pressure sensitive adhesive of the first major surface has a greater tack than the film backing of the second major surface. The difference in tack may be at least 25, 50, 75, 100, 150 grams force or greater. In other embodiments, the pressure sensitive adhesive of the first major surface has about the same tack than the film backing of the second major surface (i.e. within 10% of the average tack value).

In some embodiments, the crosslinked polydiorganosiloxane layer has a maximum tensile strength of at least 1, 2, 3, or 4 N/inch (2.54 cm). In some embodiments, the crosslinked polydiorganosiloxane layer has a maximum tensile strength of at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 N/inch (2.54 cm). In some embodiments, the crosslinked polydiorganosiloxane layer has a maximum tensile strength of no greater than 20, 15, 10, or 5 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 700, 600, 500, 400, or 300%.

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.

Additional Components

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.

In some embodiments, the adhesive article may further comprise a porous substate. A variety of porous substrate can be utilized in the articles described herein. Porous substrates can be made from a variety of (e.g. thermoplastic) organic polymer materials such as polyesters, polyurethanes, polyamides (e.g. nylon), polyimides, and polyolefins. In typical embodiments, the porous substrate is a fibrous web or an apertured film. When the film in an apertured film, the film may be apertured before or after crosslinking of the polydiorganosiloxane layer. Thus, although the article comprises a porous substrate, in some embodiments the method utilizes a non-porous organic polymer film substrate that is rendered porous during manufacturing.

Fibrous webs can be made from the same (e.g. thermoplastic) organic polymer materials as just described. Fibrous webs can also be made from various organic fibers such as cotton, wool, hemp, and flax. Although inorganic fibers (e.g., fiberglass, ceramic, and metal) would typically not be utilized in medical articles, porous substrates with inorganic fibers can be used in other adhesive articles. In some embodiments, the fibrous webs comprise nylon, polyolefin, or cellulose acetate. Fibrous webs come in many forms including, e.g., woven webs, non-woven webs, knits, scrims, and meshes.

In other embodiments, the porous substrate is an apertured organic polymer film. Apertures may be formed in the organic polymer film using as suitable technique such as die punching, as described for example in KR10-2251386. The apertures can be formed before or after applying a layer of a polydiorganosiloxane composition to the organic polymer film. The apertures can contribute to the moisture vapor permeability of the film.

In some embodiments, the organic polymer film comprises a film material that has high moisture vapor permeability (without the apertures). Suitable films include (e.g. thermoplastic) polymethane films 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). Typically, the film 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 film 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 film 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 film is at least 25, 50, 75 microns. In some embodiments, the thickness of the film is no greater than 200, 150, or 100 microns. The apertured film may have a lower tensile strength and higher elongation as compared to the same film without apertures.

The (e.g. fibrous) porous substrate may have a basis weight of at least 15, 20, 25, 30, 35, 40, 45 or 50 g/m². The (e.g. fibrous) porous substrate typically has a basis weight of no greater than 200, 150, or 100 g/m². In some embodiments, the open area (as can be determined by the basis weight and density of the material) is at least 10, 20, 30, 40, 50, 60, or 70%. The thickness of the (e.g. fibrous) porous 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 (e.g. fibrous) 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 porous 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 porous substrate is no greater than 150, 100, 75, or 50 strands per inch (2.54 cm). The fibrous porous substrate may become compressed during manufacturing resulting in a greater basis weight and lower thickness in the article.

Illustrative fibrous porous substrate are commercially available from Industrial Netting (e.g. WN0100 and WN0200), Bedford Weaving Inc, ANCI, and Tessitura A. Ghiringhelli & C.S.p.A., Azzate, Italy.

As depicted in FIGs 3-5, the porous substrate may be present proximate the first major surface, proximate the opposing second major surface, embedded within the crosslinked layer of polydiorganosiloxane composition, or a combination thereof. The presence of the porous substrate can improve web handling, increase the strength of the crosslinked layer of polydiorganosiloxane, reduce the tack or adhesion at one or both major surfaces. In some embodiments, the porous substrate may comprise the silver material instead of dispersing the silver material in the polydiorganosiloxane composition.

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.

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.

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.

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. 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. Examples

Materials Used in the Examples

Compositions were prepared in 100g batch size using a SpeedMixer® DAC600-P (Hausschild GmbH, Hamm, Germany). Silicone oil was placed in a suitable jar, MQ resin was added, and the composition was mixed at 2350 rpm and 200 mbar of vacuum for 90sec to form a homogenous mixture. For examples containing silicic acid, silicic acid was added, and the composition was mixed at 2350rpm and 200mbar of vacuum for 90 sec to form a homogenous mixture. For examples comprising CMC and/or silver compounds, those were added to the resulting composition, and the composition was mixed again at 2350rpm and 200mbar of vacuum for at least 90 sec until a homogenous mixture was obtained.

The compositions were coated onto a release liner (50 micron polyethylene terephthalate film comprising a release coating) using a knife coater. The open side of the coated sheets were exposed to ebeam 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 Tables 1, 4 and 6, followed by lamination to a release liner immediately after coating. Tensile & Elongation:

Tensile and elongation was measured according to EN ISO 527-3 using a ZwickRoell Z010 machine equipped with a 500N loadcell. Samples were cut to a size of 80mm x linch, and tabs of linch length on each side were placed in the jaws for running the test. Samples were measured in the direction of coating. Machine settings: Jaw separation: 50mm, test speed: lOOmm/min, preload: 0.1N. Tensile strength is reported as the maximum force, elongation is reported as the elongation value at the maximum tensile force. Data represents the average value of three measurements per example and standard deviation.

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.

Zone-of-Inhibition testing:

Overnight cultures of the microorganism are prepared by streaking onto Mueller-Hinton agar and incubating for at least 16 hours. An approximate 108 cfu/mL suspension using a McFarland 0.5 Turbidity standard is made in PBW. This stock solution is then diluted 1 : 100 in PBW to form the working suspension. Mueller-Hinton agar plates are seeded with 5 logs of bacteria by saturating the swab once in the working suspension while ensuring a uniform lawn of growth. Plates are then allowed to dry. Two disks (diameter: 2cm) were cut out of the coated sheets, both liners are carefully removed, and the disks are placed onto the plates using forceps. A single plate for each organism was used. Plates are incubated at 37°C and observed for zones after 24 hours, respectively.

Table 1 - Polydiorganosiloxane Compositions

Table 2 - Test Results

Table 3 Zone-of-Inhibition Testing Results:

*Slight decrease in size compared to 24 hours.

Table 4 Polydiorganosiloxane Compositions

Table 5 Test Results

The results show an increase in maximum tensile strength when silicic acid is added to the composition.

Table 6 Polydiorganosiloxane Compositions

Table 7 Mechanical Test Results

The results shows an increase in maximum tensile strength when silicic acid is added to the composition.

Claims

What is claimed is:

1. A composition comprising: polydiorganosiloxane; a silver material; and at least 1 wt.% of an oxygen-bearing metal filler of silicon, titanium, zirconium, or combination thereof.

2. The composition of claim 1 wherein the polydiorganosiloxane comprises a nonfunctional polydiorganosiloxane.

3. The composition of claim 1 -2 wherein the composition further comprises tackifying resin.

4. The composition of claims 1-3 wherein the composition further comprises a hydrophilic filler inclusive of carboxy methyl cellulose.

5. The composition of claim 1 wherein the composition is crosslinked.

6. The composition of claim 5 wherein the crosslinked composition has a higher tensile strength than the same composition without the oxygen-bearing metal filler.

7. A method of making an adhesive article comprising: a) providing a layer of a polydiorganosiloxane composition on a substrate wherein the layer comprise comprises nonfunctionalized polydiorganosiloxane and a silver material; b) exposing the layer of polydiorganosiloxane composition to radiation thereby crosslinking the layer of the polydiorganosiloxane composition.

8. The method of claim 7 wherein the substrate is a first release liner.

9. The method of claims 7-8 wherein the layer of polydiorganosiloxane composition comprises a single layer or multiple layers of the same composition or different composition.

10. The method of claim 9 wherein a first layer of a polydiorganosiloxane composition with a silver material is disposed on the substrate and a second layer of a the polydioroganosiloxane composition lacking a silver material is provided on the first layer.

11. The method of claims 1-10 wherein the polydiorganosiloxane composition has a viscosity of at least 50,000; 100,000, 250,000; 500,000; or 1,000,000 mm²/sec before crosslinking.

12. The method of claims 1-11 wherein the polydiorganosiloxane composition further comprises i) a hydrophilic filler inclusive of carboxy methyl cellulose; ii) an oxygen-bearing metal filler of silicon, titanium, zirconium, or combination thereof; or a combination thereof.

13. The method of claims 1-12 wherein the layer(s) of polydiorganosiloxane composition have a total thickness of at least 250, 300, 350, 400, 450, or 500 microns.

14. The method of claims 1-13 wherein the layer of polydiorganosiloxane composition comprises a first major surface proximate the substrate and an second opposing major surface and the method further comprising providing a porous substrate proximate the substrate, proximate the second opposing surface, or embedded within the layer of polydiorganosiloxane composition.

15. The method of claims 1-14 wherein the layer(s) of polydiorganosiloxane composition have a first major surface proximate the substrate and a second opposing major surface that is exposed to a dosage of at least 8 MRads of e-beam radiation and the first major surface is exposed to a lower dosage.

16. The method of claims 1-15 wherein the first major surface is a pressure sensitive adhesive and the second opposing major surface is a film backing.

17. An adhesive article comprising a crosslinked layer of the polydiorganosiloxane composition of claims 1-16.

18. The adhesive article of claim 17 wherein the article is a medical article, medical tape, bandage, dressing, or compression wrap.

19. The adhesive article of claim 17 for use as a medical article.

20. A method of use for an adhesive article comprising providing an adhesive article of claims 17-19 and contacting the first major surface to skin or a wound.