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WO2025103813A1 - Composition de silicone durcissable - Google Patents

Composition de silicone durcissable Download PDF

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Publication number
WO2025103813A1
WO2025103813A1 PCT/EP2024/081181 EP2024081181W WO2025103813A1 WO 2025103813 A1 WO2025103813 A1 WO 2025103813A1 EP 2024081181 W EP2024081181 W EP 2024081181W WO 2025103813 A1 WO2025103813 A1 WO 2025103813A1
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WO
WIPO (PCT)
Prior art keywords
curable silicone
silicone composition
composition
organopolysiloxane
tack
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/081181
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English (en)
Inventor
Ufuk KARABIYIK
Frankie PETRIE
Ming Guo
Steven MANKOCI
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Wacker Chemie AG
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Wacker Chemie AG
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Publication of WO2025103813A1 publication Critical patent/WO2025103813A1/fr
Pending legal-status Critical Current
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J183/00—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Adhesives based on derivatives of such polymers
    • C09J183/04—Polysiloxanes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/15—Heterocyclic compounds having oxygen in the ring
    • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
    • C08K5/1545—Six-membered rings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups

Definitions

  • the invention relates to a curable silicone composition, skin-adhesive articles, and methods of forming a skin-adhesive article.
  • Wound care dressings and other wearable medical articles often contain an adhesive layer.
  • adhesive layers may be formed by applying a silicone composition to a substrate and allowing the composition to cure. Silicone gels form particularly suitable adhesive layers.
  • the article Before being used to cover an open wound or attached to human skin, the article must be sterilized.
  • One method of sterilization for such articles involves chemical treatment such as by exposing the article to ethylene oxide.
  • ethylene oxide is toxic and the process for this method of sterilization is expensive and complex, which adds cost to the manufacture of the article.
  • Another commonly used method of sterilization which does not involve the use of a toxic gas, utilizes gamma rays, which when applied to the article can damage or disrupt the nucleic acid sequences of microbes found thereon.
  • this method of sterilization also damages known silicone adhesives, particularly, silicone adhesive gels, by decreasing the adhesive performance or tack of such materials. Often, the reduction in the tack exhibited by the adhesive layer renders the medical article unusable for its intended purpose.
  • curable silicone composition that can be cured to form a silicone gel, utilized as an adhesive, sterilized, and does not suffer a reduction in tack or peel value after sterilization that renders the medical article it is included in unusable.
  • Embodiments of a curable silicone composition are provided.
  • the curable silicone composition comprises a first organopolysiloxane having one or more groups comprising a silicon atom bonded to a hydrogen atom and a second organopolysiloxane having one or more groups comprising a carbon-carbon multiple bond.
  • the curable silicone composition also comprises a hydrosilyation catalyst and at least one stabilizing additive.
  • the at least one stabilizing additive comprises vitamin E or a derivative thereof and, optionally, a second stabilizing additive.
  • the curable silicone composition includes the second stabilizing additive and the second stabilizing additive is selected from the group consisting of benadryl, argan oil, melatonin, alizarin, an organopolysiloxane polyalkylene, a hydrophillic resin elastomer gel, tea tree oil, orange terpenes, vitamin C, glycerol, green tea, hydroxytyrosol, niacinamide, curcumin, 3,5-dimethyl-1-hexyn-3-ol, 2,2,5,7,8-pentamethyl-6-chromanol, zinc oxide, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5- methylbenzyl)-4-methylphenyl acrylate, poly [[6-[( 1 , 1 ,3,3-tetramethylbutyl)amino]-1 ,3,5- triazine-2,4-diyl][(2,2,6,6- tetramethyl)[(2,
  • the curable silicone composition further comprises one or more organosilicon crosslinkers and a hydrosilylation inhibitor.
  • the hydrosilylation inhibitor retards the addition of the one or more organosilicon crosslinkers to one or more of the organopolysiloxanes when the composition is at room temperature.
  • the curable silicone composition further comprises a filler and an MQ resin.
  • the filler is provided in an amount of 0.01 to 3.0 wt%, based on the total weight of the curable silicone composition
  • the MQ resin is provided in an amount of 0.5 to 50 wt%, based on the total weight of the curable silicone composition.
  • the MQ resin is provided in an amount of 0.5 to 5 wt%, based on the total weight of the curable silicone composition.
  • first stabilizing additive and the optional second stabilizing additive are provided in an amount of 1 to 40 wt%, which is based on the total weight of the curable silicone composition.
  • the first organopolysiloxane has a molecular weight of 500 to 100,000 g/mol
  • the second organopolysiloxane has a molecular weight of 200 to 20,000 g/mol
  • the curable silicone composition comprises 60 wt% or more of the first organopolysiloxane and the second organopolysiloxane, which is based on the total weight of the curable silicone composition.
  • the first stabilizing additive is vitamin E and the vitamin E is a tocopherol selected from an alpha-, beta-, delta-, or gamma- form thereof.
  • the curable silicone composition includes a ratio of groups having a silicon atom bonded to a hydrogen atom to groups comprising a carbon-carbon multiple bonds and the ratio is 0.5 to 0.95.
  • the second tack exhibited by the cured composition is 90 percent or more of the first tack.
  • the first tack exhibited by the cured composition is 50 to 800 gf.
  • a skin-adhesive article comprises the curable silicone composition.
  • the skin-adhesive article also comprises a substrate and a cured composition formed from the curable silicone composition.
  • the cured composition is provided over at least a portion of the substrate and is a gel.
  • Embodiments of a method of forming a skin-adhesive article are also provided.
  • the method comprises providing a substrate having a cured composition thereon.
  • the cured composition is formed from curing the curable silicone composition. After curing, the cured composition exhibits a first tack.
  • the cured composition is irradiated with gamma radiation.
  • the cured composition exhibits a second tack of at least 80 percent the first tack after being irradiated with gamma radiation.
  • irradiating the cured composition sterilizes the skinadhesive article.
  • the gamma radiation is provided at a predetermined dose rate. In one such embodiment, the predetermined dose rate delivers a dose of 10 to 50 kGy.
  • the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a nonexclusive inclusion.
  • a method, article, or composition that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or composition.
  • “or” refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
  • a curable silicone composition is provided.
  • the curable silicone composition is suitable for use in wound care dressings.
  • the composition may be utilized to provide an adhesive portion for the wound care dressing.
  • the curable silicone composition is not limited to wound care applications and can be utilized in other applications where eliminating microbes is desired. Such applications may be of the medical or non-medical variety.
  • the curable silicone composition comprises a first organopolysiloxane compound.
  • the first organopolysiloxane compound has one or more groups comprising a silicon atom bonded to a hydrogen atom.
  • a silicon atom bonded to a hydrogen atom may also be referred to herein as Si-bonded hydrogen or by using the designation “SiH.”
  • at least one of the one or more groups comprising a silicon atom bonded to a hydrogen atom is a terminal group.
  • at least one of the one or more groups comprising a silicon atom bonded to a hydrogen atom is a pendant group.
  • the first organopolysiloxane compound has two or more groups comprising a silicon atom bonded to a hydrogen atom and at least one group of the two or more groups is a terminal group and at least one group of the two or more groups is a pendant group.
  • the first organopolysiloxane compound has two or more Si-bonded hydrogen atoms, is linear, cyclic, or branched, and composed of units of the general formula (I)
  • R 4 independently at each occurrence, is a radical free from aliphatic carbon-carbon multiple bonds, c is 0, 1 , 2, or 3, and d is 0, 1 , or 2, with the proviso that the sum of c + d is less than or equal to 3 and there are at least two Si-bonded hydrogen atoms per molecule.
  • R 4 may comprise one or more monovalent or polyvalent radicals, in which case the polyvalent radicals, such as divalent, trivalent, and tetravalent radicals, for example, join two or more, such as two, three, or four, for instance, siloxy units of the formula (I) to one another.
  • polyvalent radicals such as divalent, trivalent, and tetravalent radicals, for example, join two or more, such as two, three, or four, for instance, siloxy units of the formula (I) to one another.
  • R 4 may be a monovalent radical of the group comprising - F, -Cl, -Br, OR 6 , -CN, -SCN, -NCO, and SiC-bonded, substituted, or unsubstituted hydrocarbon radicals which may be interrupted by oxygen atoms or by the group -C(O)-, and divalent radicals Si-bonded on both sides in accordance with formula (I).
  • R 4 comprises SiC-bonded, substituted hydrocarbon radicals
  • preferred substituents include halogen atoms, phosphorus-containing radicals, cyano radicals, -OR 6 , -NR 6 -, -NR 6 2, - NR 6 -C(O)-NR 6 2, -C(O)-NR 6 2, -C(O)R 6 , -C(O)OR 6 , -SO 2 -Ph, and -CeFs.
  • R 6 independently at each occurrence, identically or differently, denotes a hydrogen atom or a monovalent hydrocarbon radical having 1 to 20 carbon atoms, and Ph is the phenyl radical.
  • R 4 include alkyl radicals, such as the methyl, ethyl, n- propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl radical, hexyl radicals, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, octyl radicals, such as the n-octyl radical and isooctyl radicals, such as the 2,2,4- trimethylpentyl radical, nonyl radicals, such as the n-nonyl radical, decyl radicals, such as the n-decyl radical, dodecyl radicals, such as the n-dodecyl radical, and octadecyl radicals, such as the n
  • R 4 is a substituted radical
  • suitable examples include haloalkyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2’,2‘,2‘-hexafluoroisopropyl radical, the heptafluoroisopropyl radical, haloaryl radicals, such as the o-, m-, and p- chlorophenyl radical, -(CH 2 )-N(R 6 )C(O)NR 6 2, -(CH 2 )o-C(O)NR 6 2, -(CH 2 )o-C(O)R 6 , - (CH 2 )O-C(O)OR 6 , -(CH 2 )O-C(O)NR 6 2, -(CH2)-C(O)-(CH 2 ) P C(O)CH3, -(CH 2 )-O-CO-R 6 , - (CH2)-NR 6 -(CH 2 ) P -
  • R 4 as divalent radicals are radicals which derive from the monovalent examples stated above for R 4 by virtue of an additional bond taking place through substitution of a hydrogen atom; examples of such radicals are -(CH2)-, -CH(CH3)-, -C(CH3)2-, -CH(CH3)- CH2-, -C6H4-, -CH(Ph)-CH2-, -C(CF 3 )2-, -(CH2)O-C 6 H4-(CH2)O-, -(CH2)O-C6H4-C 6 H4-(CH2)O, -(CH 2 O) P , (CH2CH 2 O)O, -(CH2)O-OX-C6H4-SO2-C6H4-OX-(CH2)O-, where x is 0 or 1 , and Ph, 0, and p have the definition stated above.
  • R 4 comprises a monovalent, SiC-bonded, optionally substituted hydrocarbon radical which has 1 to 18 carbon atoms and is free from aliphatic carboncarbon multiple bonds, more preferably a monovalent, SiC-bonded hydrocarbon radical which has 1 to 6 carbon atoms and is free from aliphatic carbon-carbon multiple bonds, and more particularly the methyl or phenyl radical.
  • the first organopolysiloxane compound preferably contains Si-bonded hydrogen in a range from 0.01 to 1.7 percent by weight (wt%), based on the total weight of the first organopolysiloxane compound.
  • the molecular weight of the first organopolysiloxane compound may likewise vary within wide limits, as for instance between 10 2 and 10 6 g/mol.
  • the first organopolysiloxane compound may be, for example, an SiH-functional oligosiloxane of relatively low molecular mass, such as tetramethyldisiloxane, or alternatively may be a silicone resin having SiH groups or a high-polymeric polydimethylsiloxane that possesses SiH groups within the chain or terminally.
  • the first organopolysiloxane compound may be provided as all or a portion of a component (A).
  • component (A) may comprise a mixture of organopolysiloxanes including one or more embodiments of the first organopolysiloxane compound described above.
  • component (A) may comprise a mixture of organopolysiloxanes and the mixture may comprise an organopolysiloxane having at least one terminal group comprising a silicon atom bonded to a hydrogen atom and an organopolysiloxane having at least one pendant group comprising a silicon atom bonded to a hydrogen atom. Additional organopolysiloxanes may also be suitable for use in component (A).
  • component (A) may contain a mixture of molecules including two or more distinct organopolysiloxanes.
  • Particularly preferred is the use of low molecular mass, SiH-functional compounds such as tetrakis(dimethylsiloxy)silane and tetramethylcyclotetrasiloxane, and also of SiH-containing siloxanes of higher molecular mass, such as poly(hydrogenmethyl)siloxane and poly(dimethylhydrogenmethyl)siloxane with a viscosity at 25°C of 10 to 20,000 mPa s, or similar SiH-containing compounds in which some of the methyl groups have been replaced by 3,3,3-trifluoropropyl or phenyl groups.
  • the structure of the molecules included in component (A) is also not fixed; in particular, the structure of a SiH-containing organopolysiloxane of relatively high molecular mass, in other words oligomeric or polymeric, may be linear, cyclic, branched, or else resinous, network-like.
  • Linear and cyclic organopolysiloxanes are composed preferably of units of the formula R 4 3SiOi/2, HR 4 2SiOi/2, HR 4 SiO2/2, and R 4 2SiO2/2, with R 4 having the definition indicated above.
  • Branched and network-like organopolysiloxanes additionally include trifunctional and/or tetrafunctional units, with preference being given to those of the formulae R 4 SiOs/2, HSiOs/2, and SiCU/2, where R 4 has the definition indicated above.
  • the amount of component (A) in the curable silicone composition is preferably such that the molar ratio of SiH groups to al iphatically unsaturated groups in the composition is 0.1 to 20, more preferably between 0.3 and 2.0.
  • the first organopolysiloxane has a molecular weight of 100,000 g/mol or less. In certain embodiments, the first organopolysiloxane has a molecular weight of 500 - 100,000 g/mol. More preferably, the first organopolysiloxane has a molecular weight of 35,000 g/mol or less. In these embodiments, the first organopolysiloxane may have a molecular weight of 500 - 35,000 g/mol. The preferred molecular weight range for the first organopolysiloxane may have a molecular weight of 1000 - 25,000 g/mol.
  • the cured silicone composition which is preferably a gel, is formed with a low elastic modulus.
  • a low elastic modulus is below 5,000 Pa based on rheological analyses via dynamic mechanical analysis.
  • the curable silicone composition comprises a second organopolysiloxane compound.
  • the second organopolysiloxane compound has one or more groups comprising a carbon-carbon multiple bond.
  • the second organopolysiloxane compound may be provided as a portion of a component (B).
  • the curable silicone composition may be formed by providing a component (B).
  • Component (B) may comprise the second organopolysiloxane compound or another compound.
  • the second organopolysiloxane compound may be a linear organopolysiloxane.
  • the second organopolysiloxane compound may have one or more terminal groups comprising a carbon-carbon multiple bond, which may also be referred to herein as an aliphatic multiple bond.
  • the second organopolysiloxane compound may comprise a SiC-bonded radical having an aliphatic carbon-carbon multiple bond, which may be referred to herein as an aliphatically unsaturated radical.
  • component (B) comprises another linear compound, such a compound may comprise aliphatic carbon-carbon multiple bonds.
  • component (B) may comprise an organopolysiloxane compound or another compound.
  • component (B) comprises a silicon-free organic compound
  • such a compound may comprise at least two aliphatically unsaturated groups.
  • the second organopolysiloxane compound has at least two aliphatically unsaturated groups.
  • component (B) may comprise a mixture of compounds.
  • component (B) may comprise the second organopolysiloxane compound, wherein the second organopolysiloxane compound has at least two aliphatically unsaturated groups, and a silicon-free organic compound that has at least two aliphatically unsaturated groups.
  • component (B) may comprise a mixture of discrete organopolysiloxane compounds, including the second organopolysiloxane compound, and these compounds may each comprise aliphatic carbon-carbon multiple bonds.
  • the aliphatic carbon-carbon multiple bond may be included in a terminal group or be located in another group of the organopolysiloxane compound.
  • silicon-free organic compounds suitable for use in component (B) are 1 ,3,5-trivinylcyclohexane, 2,3-dimethyl-1 ,3-butadiene, 7-methyl-3-methylene-1 ,6- octadiene, 2-methyl-1 ,3-butadiene, 1 ,5-hexadiene, 1 ,7-octadiene, 4,7-methylene- 4,7,8,9-tetrahydroindene, methylcyclopentadiene, 5-vinyl-2-norbornene, bicyclo[2.2.1]hepta-2,5-diene, 1 ,3-diisopropenylbenzene, polybutadiene containing vinyl groups, 1 ,4-divinylcyclohexane, 1 ,3,5-triallylbenzene, 1 ,3,5-trivinylbenzene, 1 ,2,4- trivinylcyclohexane, 1 ,3,5
  • Organopolysiloxane compounds known in the art are suitable for use in component (B) and as the second organopolysiloxane compound.
  • organopolysiloxanes include, for example, silicone block copolymers having urea segments, silicone block copolymers having amide segments and/or imide segments and/or ester-amide segments and/or polystyrene segments and/or silarylene segments and/or carborane segments, and silicone graft copolymers having ether groups.
  • Organopolysiloxane compounds suitable for use as the second organopolysiloxane compound are preferably linear or branched organopolysiloxanes comprising units of the general formula (II)
  • R 4 independently at each occurrence, is a radical free from aliphatic carbon-carbon multiple bonds
  • R 5 independently at each occurrence, identically or differently, is a monovalent, substituted or unsubstituted, SiC-bonded hydrocarbon radical having at least one aliphatic carbon-carbon multiple bond, a is 0, 1 , 2, or 3, and b is 0, 1 , or 2, with the proviso that the sum a + b is less than or equal to 3 and there are at least 2 radicals R 5 per molecule.
  • R 4 has the definition indicated above.
  • R 5 comprises any desired groups amenable to an addition reaction (hydrosilylation) with an SiH-functional compound.
  • R 5 comprises SiC-bonded, substituted hydrocarbon radicals, preferred substituents are halogen atoms, cyano radicals, and -OR 6 , where R 6 has the abovestated definition.
  • R 5 comprises alkenyl and alkynyl groups having 2 to 16 carbon atoms, such as vinyl, allyl, methallyl, 1 -propenyl, 5-hexenyl, ethynyl, butadienyl, hexadienyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, vinylcyclohexylethyl, divinylcyclohexylethyl, norbornenyl, vinylphenyl, and styryl radicals, with vinyl, allyl, and hexenyl radicals being particularly preferred for use.
  • alkenyl and alkynyl groups having 2 to 16 carbon atoms such as vinyl, allyl, methallyl, 1 -propenyl, 5-hexenyl, ethynyl, butadienyl, hexadienyl, cyclopentenyl, cyclopentadien
  • the molecular weight of the second organopolysiloxane compound and any organopolysiloxane compound(s) utilized as a portion of component (B) may vary within wide limits, as for instance between 10 2 and 10 6 g/mol.
  • the second organopolysiloxane compound may be a relatively low molecular mass, alkenyl- functional oligosiloxane such as, for example, 1 ,2-divinyltetramethyldisiloxane, or is a polydimethylsiloxane with a molecular weight of 10 5 g/mol (number average determined by means of NMR) that possesses in-chain or terminal Si-bonded vinyl groups.
  • the structure of the second organopolysiloxane compound may vary between embodiments depending on the desired properties of the composition.
  • the structure in which the second organopolysiloxane compound has a relatively high molecular mass, in other words an oligomeric or polymeric siloxane, the structure may be linear, cyclic, branched, resinous, network-like or another type of polymer matrix.
  • Linear and cyclic polysiloxanes are preferably composed of units of the formula R 4 3SiOi/2, R 5 R 4 2SiOi/2, R 5 R 4 SiOi/2, and R 4 2SiO2/2, where R 4 and R 5 have the definition indicated above.
  • Branched and network-like polysiloxanes additionally include trifunctional and/or tetrafunctional units, with preference being given to those of the formula R 4 SiOs/2, R 5 SiO3/2, and SiCU/2. Also, as noted above, mixtures of these different organopolysiloxanes may be utilized in component (B).
  • the second organopolysiloxane compound is a vinyl-functional, substantially linear polydiorganosiloxane having a viscosity of 0.01 to 500,000 Pa s, more preferably of 0.1 to 100,000 Pa s, in each case the viscosity being measured at 25°C.
  • the second organopolysiloxane has a molecular weight of 20,000 g/mol or less. In certain embodiments, the second organopolysiloxane has a molecular weight of 200 - 20,000 g/mol. More preferably, the second organopolysiloxane has a molecular weight of 5,000 g/mol or less. Even more preferably, the second organopolysiloxane has a molecular weight of 3500 g/mol or less. In these embodiments, the second organopolysiloxane may have a molecular weight of 200 - 3,500 g/mol.
  • the cured silicone composition which is preferably a gel, is formed with the desired adhesive and elastic modulus properties.
  • molecules with the molecular weights described above exhibit superior crosslinking features over larger molecular weight molecules when utilized to form a cured silicone composition suitable for the applications mentioned above.
  • This desired crosslinking feature results in adhesive and elastic modulus properties that are desired for the curable silicone composition once cured.
  • the curable silicone composition may contain 30-95 wt%, preferably 30-80 wt%, and more preferably 40-70 wt% of the organopolysiloxane compound(s) of component (B). In other embodiments, the curable silicone composition may contain 0.1 -60 wt%, preferably 0.5-50 wt%, and more preferably 1 -30 wt% of the organopolysiloxane compound(s) of component (A).
  • the curable silicone composition comprises an alternative to the organopolysiloxanes described above for use in components (A) and (B), then such an alternative molecule may be present at SO- 95 wt%, preferably 30-80 wt%, more preferably 40-70 wt% in the curable silicone composition.
  • a component (C) may be utilized.
  • Component (C) may comprise an organopolysiloxane compound.
  • the organopolysiloxane compound may have one or more terminal groups comprising a silicon atom bonded to a hydrogen atom.
  • the organopolysiloxane compound may have one or more terminal groups comprising a carbon-carbon multiple bond.
  • component (C) may comprise a mixture of organopolysiloxanes.
  • component (C) may comprise organopolysiloxane compounds having one or more terminal groups comprising a silicon atom bonded to a hydrogen atom, organopolysiloxane compounds having one or more terminal groups comprising a carbon-carbon multiple bond, and/or organopolysiloxane compounds that do not include any reactive groups.
  • Component (C) may also comprise a reinforcing filler or another additive.
  • component (C) may comprise a non-silicone oligomeric compound such as, for example, a polyether or a polymeric compound such as, for example, acrylates, urethanes, polyesters, and copolymers of the same with siloxanes.
  • organopolysiloxane compound has aliphatic carbon-carbon multiple bonds and Si-bonded hydrogen atoms
  • suitable examples are preferably composed of units of the general formula (III), (IV), and (V)
  • R 4 and R 5 have the definitions indicated for them above, f is 0, 1 , 2, or 3, g is 0, 1 , or 2, and h is 0, 1 , or 2, with the proviso that per molecule there are at least 2 radicals R 5 and at least 2 Si- bonded hydrogen atoms.
  • Organopolysiloxane compounds that have aliphatic carbon-carbon multiple bonds and Si-bonded hydrogen atoms preferably possess an average viscosity of 0.01 to 500,000 Pa s, more preferably 0.1 to 100,000 Pa s, in each case at 25°C. Such organopolysiloxanes are preparable by techniques that are known in the art.
  • the curable silicone composition is cured through crosslinking of the first and second organopolysiloxane compounds.
  • the curable silicone composition is formed by addition-crosslinking.
  • the curable silicone composition may comprise a crosslinker.
  • the crosslinker may be an organopolysiloxane compound.
  • the curable silicone composition may comprise a third organopolysiloxane compound.
  • Preferred organopolysiloxane compounds suitable for use as crosslinkers have three or more groups comprising a silicon atom bonded to a hydrogen atom.
  • the crosslinker includes an SiH-functional organopolysiloxane compound having an average of at least two SiH groups.
  • the crosslinker may be a mixture of various SiH-functional organosilicon compounds.
  • the crosslinker includes a linear, cyclic, branched or resinous organopolysiloxane having Si-bonded hydrogen atoms, composed of units of the formula R 4 cHdSiO(4-c-d) where
  • R 4 has the definition given above, c is 0, 1 , 2 or 3 and d is 0, 1 or 2, with the proviso that the sum total of (c+d) is not more than 3 and there is an average of at least two Si-bonded hydrogen atoms per molecule.
  • the crosslinker contains SiH groups in the range from 0.04 to 1.7 percent by weight (% by weight) based on the total weight of the organopolysiloxanes utilized as crosslinkers.
  • the molecular weight of the crosslinker may vary within wide limits, for instance between 400 and 25,000 g/mol.
  • the crosslinker may be an SiH-functional organopolysiloxane compound of relatively low molecular weight, such as tetramethyldisiloxane, a high- polymeric polydimethylsiloxane having SiH groups in chain or terminal positions, or a silicone resin having SiH groups.
  • organopolysiloxane crosslinkers of low molecular weight, such as tetrakis(dimethyl-siloxy)silane and tetramethylcyclotetrasiloxane and SiH-containing organopolysiloxanes, such as, for example, poly(hydrogenmethyl)siloxane and poly(dimethylhydrogenmethyl)siloxane having a viscosities in the range of 10 to 1 ,000 mPa s (at 25°C and 0.8 sec -1 ).
  • the crosslinker is compatible with RTV-2 siloxane systems (homogeneously miscible or at least emulsifiable).
  • the curable silicone composition before curing, has a predetermined ratio of groups having a silicon atom bonded to a hydrogen atom to groups comprising a carbon-carbon multiple bond.
  • the ratio of groups having a silicon atom bonded to a hydrogen atom to groups comprising a carbon-carbon multiple bond is 0.5 to 0.95.
  • the ratio of groups having a silicon atom bonded to a hydrogen atom to groups comprising a carbon-carbon multiple bond in the curable silicone composition is 0.5 to 0.75.
  • providing a curable silicone composition with the ratios described above enables the curable silicone composition to act as an adhesive after curing and helps to establish the tack of the cured curable silicone composition before the composition is irradiated with gamma radiation.
  • a hydrosilylation catalyst is provided.
  • the hydrosilyation catalyst may be provided as a portion of one of the components mentioned above.
  • the two components may comprise all constituents referred to above in any desired combinations, generally with the proviso that one component does not simultaneously comprise organopolysiloxane compounds with aliphatic multiple bonds, organopolysiloxane compounds with Si-bonded hydrogen atoms, and the hydrosilylation catalyst.
  • the hydrosilyation catalyst may be provided as a portion of component (A) or component (B).
  • Hydrosilylation catalysts known in the art are suitable for use in the curable silicone composition.
  • the hydrosilylation catalyst may include a platinum-group metal such as, for example, platinum, rhodium, ruthenium, palladium, osmium, or iridium, or may be an organometallic compound, or a combination thereof.
  • Suitable examples of hydrosilylation catalysts are compounds such as hexachloroplatinic(IV) acid, platinum dichloride, platinum acetylacetonate, and complexes of said compounds encapsulated in a matrix or in a core/shell-like structure.
  • platinum complexes with a low molecular weight of organopolysiloxanes include 1 ,3-diethenyl-1 ,1 ,3,3- tetramethyldisiloxane complexes with platinum.
  • suitable hydrosilylation catalysts are platinum-phosphite complexes, platinum-phosphine complexes, or alkylplatinum complexes such as derivatives of cyclopentadienyltrimethylplatinum(IV), cyclooctadienyldimethylplatinum(ll), or diketonato complexes, such as bisacetylacetonatoplatinum(ll), for example.
  • the platinum-containing compound may be encapsulated within a resin matrix.
  • the concentration of catalyst for catalyzing the hydrosilylation crosslinking reaction may be in an amount between 0.1 and 1 ,000 parts per million (ppm), 0.5 and 100 ppm, or 1 and 25 ppm of the platinum group metal, depending on the total weight of the curable silicone composition.
  • the composition may be a gel.
  • the gel has a crosslinked structure.
  • a crosslinked structure can form when the total number of reacting groups is greater than 4.
  • crosslinking can happen, for example, between a first organopolysiloxane compound, which contains more than two Si-bonded hydrogen atoms, and a second organopolysiloxane compound, which includes at least two reactive al iphatical ly unsaturated groups, or alternatively between a first organopolysiloxane compound containing two Si-bonded hydrogen atoms and a second organopolysiloxane compound with more than two aliphatically unsaturated radicals.
  • the first organopolysiloxane compound and the second organopolysiloxane compound are crosslinked to the gel point of the mixture.
  • the curable silicone composition may exhibit a viscosity of 50-100,000 centipoise.
  • the curable silicone composition may comprise an organopolysiloxane resin. It has been discovered that providing the organopolysiloxane resin in particular amounts, based on the total weight of the composition, helps to improve the stability of the composition when it is irradiated with gamma radiation during curing.
  • the curable silicone composition may comprise 0.5 wt% or more organopolysiloxane resin, based on the total weight of the composition.
  • the curable silicone composition comprises 0.5 to 50 wt% organopolysiloxane resin, which is based on the total weight of the composition.
  • the curable silicone composition comprises 0.5 to 10 wt% organopolysiloxane resin, which is based on the total weight of the composition. However, it is preferred that the curable silicone composition comprises 0.5 to 5 wt% organopolysiloxane resin, which is based on the total weight of the composition. More preferably, the curable silicone composition comprises 0.5 to 3 wt% organopolysiloxane resin, which is based on the total weight of the composition.
  • the organopolysiloxane resin is a vinyl functional MQ resin or similar, highly crosslinked resin containing M, Q, and/or T moieties, and optionally a minor amount of D moieties.
  • the term "resin” is used in its customary meaning, i.e. a highly three dimensionally crosslinked polymer containing a majority of M units, and T and/or Q units.
  • an MT, MQ, and MQT resin is preferred.
  • An organopolysiloxane resin that comprises M and Q units is particularly preferred.
  • M refers to monofunctional units while the term “Q” refers to tetrafunctional units.
  • an MQ resin comprises predominantly M units, wherein silicon is attached to only one oxygen in the cross-linked molecules, and SiO4,2 "Q" units, wherein each silicon atom is attached to four other oxygen atoms, resulting in a high level of crosslinking.
  • the MQ resin may comprise small amounts of difunctional R2SiO2/2 units and trifunctional RSiOs/2 units ("D" and "T” units, respectfully).
  • MQ resins suitable for use in the curable silicone composition may be produced by the hydrolysis of silanes such as tetraethoxysilane, vinyldimethylethoxysilane and trimethylethoxysilane.
  • the MQ resin may retain some residual alkoxy functionality as a result of the method of its preparation and will occasionally include other functionalities such as silanol or halo functionality as well.
  • the MQ resin contains approximately 1 .2 to 1 .8 weight percent vinyl functionality.
  • MQ resins having unsaturated groups other than vinyl, including vinyloxy, allyl, allyloxy, propenyl, etc., may also be utilized.
  • MQ resins formed as a co-hydrolysis product of tetraalkoxy silane and trimethylalkoxy silane may be suitable.
  • Such MQ resins may comprise a three-dimensional network of polysilicic acid units that has trimethylsilyl end groups.
  • the average molecular weight of such MQ resins can be controlled by the ratio of M to Q units in the resin.
  • the ratio of M to Q units is from 0.5 to 1 , with a ratio of approximately 0.67 being preferred.
  • MQ resins mentioned above may be used alone, in combination with each other, or with other unsaturated resins.
  • Preferred commercially available MQ resins include MQ resin 804 and MQ resin 803, both are available from Wacker Chemical Corporation.
  • the organopolysiloxane resin may contain a variety of unsaturated groups for the above-mentioned hydrosilylation reactions, including both ethylenic and unsaturation. It is preferable, although not mandatory, that the unsaturation be at a terminal location. For example, when hexenyl unsaturated groups are present, terminal (co-) hexenyl groups are preferred.
  • the unsaturated groups may also, as indicated, be unsaturated ether groups such as vinyl ether groups, and may be other heteroatom containing groups as well, i.e. (meth)acryloxy groups. Vinyl and allyl groups are most preferred.
  • the curable silicone composition may comprise at least one stabilizing additive.
  • curable silicone compositions exhibit a distortion in their adhesive properties after being cured and then irradiated with gamma radiation in the known sterilization processes.
  • providing at least one stabilizing additive inhibits the distortion(s) caused by irradiation with gamma radiation and helps maintain good adhesive properties.
  • a stabilizing additive from those described herein helps inhibit damage to the curable silicone composition, after it has cured, when the cured composition is exposed to doses of gamma radiation from 10 to 50 kGy.
  • the curable silicone composition may comprise up to 40 wt% of stabilizing additive(s), based on the total weight of the curable silicone composition.
  • the curable silicone composition comprises 0.5 to 40 wt% of stabilizing additive(s), based on the total weight of the curable silicone composition.
  • the curable silicone composition comprises 0.5 to 15 wt% of stabilizing additive(s), based on the total weight of the curable silicone composition.
  • the curable silicone composition comprises 1.0 to 15 wt% of stabilizing additive(s), based on the total weight of the curable silicone composition.
  • One or more stabilizing additives may be provided as a portion of component (A), component (B), component (C), or in two or more of these components.
  • the stabilizing additive is an antioxidant or is a mixture of molecules and comprises one or more antioxidants.
  • the curable silicone composition comprises at least one stabilizing additive selected from the group consisting of vitamin E, derivatives of vitamin E, benadryl, argan oil, melatonin, alizarin, an organopolysiloxane polyalkylene, a hydrophillic resin elastomer gel, tea tree oil, orange terpenes, vitamin C, glycerol, green tea, hydroxytyrosol, niacinamide, curcumin, 3,5- dimethyl-1 -hexyn-3-ol, 2,2,5,7,8-pentamethyl-6-chromanol, zinc oxide, 2-tert-butyl-6-(3- tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, poly [[6-[( 1 , 1 ,3,3- tetramethylbutyl)amino]-1 ,3,5-
  • the at least one stabilizing additive comprises vitamin E or a derivative thereof. In other embodiments, it may be desired to provide two or more stabilizing additives. In these embodiments, the at least one stabilizing additive comprises a first stabilizing additive. Preferably, the first stabilizing additive comprises vitamin E or a derivative thereof.
  • the term “vitamin E“ refers to a tocopherol molecule, preferably d-alpha-tocopherol, which is also known as natural vitamin E. However, as used herein, vitamin E can also refer to a tocopherol mixture that comprise d-alpha-tocopherol or one or more of alpha-, beta-, delta-, and gamma-forms of tocopherol.
  • a “derivative" of vitamin E refers to at least one tocotrienol molecule, which can be provided in a purified form or in a mixture that comprises one or more of the alpha-, beta-, delta-, or gamma-form of a tocotrienol.
  • the curable silicone composition can optionally include a second stabilizing additive.
  • the second stabilizing additive is selected from the group consisting of benadryl, argan oil, melatonin, alizarin, an organopolysiloxane polyoxyalkylene, a hydrophillic resin elastomer gel, tea tree oil, orange terpenes, vitamin C, glycerol, green tea, hydroxytyrosol, niacinamide, curcumin, 3,5-dimethyl-1-hexyn-3-ol, 2,2,5,7,8-pentamethyl-6-chromanol, zinc oxide, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5- methylbenzyl)-4-methylphenyl acrylate, poly [[6-[( 1 , 1 ,3,3-tetramethylbutyl)amino]-1 ,3,5- triazine-2,4-diyl][(2,2,6,6
  • argan oil refers to a mixture formed from collecting the product of pressing the nuts of the argan tree. This mixture may include glycerol ester and fatty acids.
  • argan oli is composed of fatty acids and phenolic compounds, which include tocopherols, caffeic acid, oleuropein, vanillic acid, tyrosol and catechol.
  • a preferred fatty acid is linoleic (omega-6).
  • a suitable argan oil for use in the curable silicone composition is sold by Jedwards International, Inc.
  • organopolysiloxane polyoxyalkylene is provided as a stabilizing additive, it is preferred to use organopolysiloxanes polyoxyalkylenes of the general formula:
  • the organopolysiloxane polyoxyalkylene may be covalently bonded and exhibit a viscosity of approximately 400 mPa s.
  • An example of a commercially available organopolysiloxane polyoxyalkylene suitable as a stabilizing additive is sold under the name Belsil® OW 1500 and by Wacker Chemie AG.
  • a hydrophilic resin elastomer is provided as a stabilizing additive, it is preferred to use a hydrophilic resin elastomer that comprises a silicone copolymer network blended with a non-volatile dimethicone and a silicone polyglucoside.
  • the silicone polyglucoside is nonionic with a hydrophilic-lipophilic balance in the range of 6 - 7.
  • Suitable hydrophilic resin elastomers may exhibit a viscosity of approximately 150,000 mPa s. mPa s.
  • An example of a commercially available organopolysiloxane polyoxyalkylene suitable as a stabilizing additive is sold under the name Belsil® REG 1103 B and by Wacker Chemie AG.
  • a hydroxytyrosol is provided as a stabilizing additive
  • suitable carriers include carbohydrate based carriers such as, for example, maltodextrin carriers.
  • An example of a commercially available hydroxytyrosol suitable as a stabilizing additive is sold under the name HTEssence® and by Wacker Chemie AG.
  • the curable silicone composition may comprise one or more other additives, which may be provided as a portion of component (A), component (B), or component (C) if provided.
  • the curable silicone composition may comprise a reinforcing filler.
  • Suitable reinforcing fillers include fumed or precipitated silicas having BET surface areas of at least 50 m 2 /g, carbon blacks, activated carbons such as furnace black and acetylene black, or mixtures thereof.
  • the stated silica fillers may have a hydrophilic character or may have been made hydrophobic by known methods. Suitable hydrophobic silicas are the Wacker HDK® brand, which are manufacured and sold by Wacker Chemical Corporation.
  • the amount of reinforcing filler in the curable silicone composition may be within the range from 0 to 10 wt%, preferably 0.01 to 5 wt%, more preferably 0.01 to 3 wt%, based on the total weight of the curable silicone composition.
  • the filler utilized is surface treated.
  • the surface treatment is obtained by the methods known in the art for hydrophobizing finely divided fillers.
  • the filler utilized may have a carbon content of at least 0.01 up to a maximum of 20 wt%, preferably between 0.1 and 10 wt%, more preferably between 0.5 to 5 wt%.
  • the filler is a surface-treated silica having 0.01 to 2 wt% of Si-bonded, al iphatical ly unsaturated groups. These groups are, for example, Si-bonded vinyl groups.
  • the filler is provided as a single species or as a mixture of two or more finely divided filler(s).
  • additives may be provided in the curable silicone composition in a fraction of up to 70 wt%, preferably 0.0001 to 40 wt%, based on the total weight of the composition.
  • These additives may be, for example, inert fillers, resinous polyorganosiloxanes, different from the siloxanes described above, reinforcing and nonreinforcing fillers, fungicides, fragrances, rheological additives, corrosion inhibitors, oxidation inhibitors, light stabilizers, flame retardants, and agents for influencing the electrical properties, dispersing assistants, solvents, adhesion promoters, pigments, dyes, plasticizers, organic polymers, heat stabilizers, etc.
  • additives such as finely ground quartz, diatomaceous earth, clays, chalk, lithopone, carbon blacks, graphite, metal oxides, metal carbonates, metal sulfates, metal salts of carboxylic acids, metal dusts, fibers, such as glass fibers, polymeric fibers, polymeric powders, metal dusts, dyes, pigments, etc.
  • Additional fillers may be heat-conducting or electrically conducting. A combination of fillers with different particle sizes and different particle size distributions may also be utilized.
  • the curable silicone composition may comprise additional additives such as one or more solvents, hydrophilic compounds, antimicrobial agents, and/or one or more inhibitors.
  • the curable silicone composition may comprise a hydrosilyation inhibitor. Such inhibitors enable the curable silicone composition to exhibit a predetermined processing life, curing onset temperature, and curing rate.
  • acetylenic alcohols such as 1 -ethynyl-1 - cyclohexanol, 2-methyl-3-butyn-2-ol, and 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1- dodecyn-3-ol
  • polymethylvinylcyclosiloxanes such as 1, 3,5,7- tetravinyltetramethyltetracyclosiloxane
  • alkyl maleates such as diallyl maleates, dimethyl maleate, and diethyl maleate
  • alkyl fumarates such as diallyl fumarate and diethyl fumarate
  • organic hydroperoxide such as 1
  • the hydrosilylation inhibitor is provided in the curable silicone composition in a quantitative fraction of 0.00001 to 5 wt%, based on the total weight of the curable silicone composition.
  • the hydrosilylation inhibitor is provided in the curable silicone composition in an amount of 0.00005 to 2 wt%, and more preferably at 0.0001 to 1 wt%, which in each case is based on the total weight of the composition.
  • the curable silicone composition may be made by preparing component (A).
  • component (A) comprises the organopolysiloxane(s) described above for component (A).
  • component (A) may comprise the stabilizing additive(s), hydrosilyation catalyst, an organopolysiloxane resin, and/or one or more additional additives.
  • the constituents of component (A) may be mixed to form a mixture. Mixing can be done at a predetermined rate, for a predetermined period of time, and utilizing commercially available mixing devices such as, for example, a Speedmixer® or a Dispermat® fitted with a dissolver blade.
  • the curable silicone composition may be made by preparing component (B).
  • component (B) comprises the organopolysiloxane described above for component (B).
  • component (B) may comprise the stabilizing additive(s), hydrosilyation catalyst, organopolysiloxane resin, and/or one or more additional additives.
  • the constituents of component (B) are mixed to form a mixture. Mixing can be done at a predetermined rate, for a predetermined period of time, and utilizing commercially available mixing devices such as, for example, the mixing devices mentioned above.
  • the curable silicone composition is made by preparing component (C).
  • the curable silicone composition may be made by preparing three mixtures and combining those mixtures.
  • component (C) comprises an organopolysiloxane like those described above for component (C).
  • component (C) may comprise the stabilizing additive(s), hydrosilyation catalyst, organopolysiloxane resin, and/or one or more additional additives.
  • the constituents of component (C) are mixed to form a mixture.
  • the curable silicone composition may be made by initially preparing three mixtures. Mixing can be done at a predetermined rate, for a predetermined period of time, and utilizing commercially available mixing devices as described above.
  • component (A) and component (B) may be mixed to form a mixture.
  • Mixing can be done at a predetermined rate, for a predetermined period of time, and utilizing commercially available mixing devices such as, for example, the mixing devices mentioned above.
  • the mixture may also include component (C). If not included in components (A), (B) or (C) or if additional amounts are desired to be included in the curable silicone composition, a particular constituent can be added to the mixture. The addition of one or more of these constituents can be achieved at the time of mixing component (A), component (B), component (C) or can occur simultaneously or sequentially by way of further mixing.
  • the curable silicone composition can be stored under commercially standard conditions, e.g. time, temperatures, and pressures. Further, once mixed, the curable silicone composition can be applied to a substrate prior to curing. In some embodiments, the curable silicone composition may coat a substrate such as, for example, a dressing. In these embodiments, the curable silicone composition may be cast and cured on the substrate to form the gel. The curable silicone composition can be applied to the substrate to provide any desired thickness, pattern, or morphology. Suitable substrates are known in the art.
  • the curable silicone composition can be cured at a predetermined temperature and for a predetermined period of time.
  • the mixture can be cured at a temperature of 40 to 140°C, preferably 60 to 130°C, for 5 seconds to 2 hours, preferably 10 seconds to 30 minutes. Curing the curable silicone composition provides a gel. After being applied to a substrate and cured, the curable silicone composition to be utilized in traditional wound care dressings and form a homogenous gel adhesive layer.
  • the curable silicone composition may also function as an adhesive.
  • the adhesive may be utilized as the adhesive portion of a wound care dressing.
  • the composition can function as an adhesive because the tack exhibited is sufficiently high.
  • the tack exhibited by the gel may be greater than 50 grams of force (gf).
  • the tack exhibited by the gel is greater than 100 gf.
  • the tack must not be so strong that the skin of the user is damaged when the dressing is removed.
  • the tack exhibited by the gel is less than 800 gf.
  • the tack exhibited by the gel may be 50 to 800 gf.
  • the tack exhibited by the gel is 100 to 500 gf. More preferably, the tack exhibited by the gel is 200 to 500 gf.
  • the tack exhibited by the gel can be measured by known methods. For example, the tack of the gel can be measured with a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the now cured curable silicone composition is irradiated with gamma radiation.
  • Gamma radiation can be provided by known devices and under known conditions.
  • Gamma radiation doses can be in the range of from 10 to 50 kGy, with a dose of 25 kGy being preferred over an exposure time of 100 minutes.
  • the curable silicone composition does not suffer from the same shortcomings of the known compositions and the tack it initially exhibits, which is the tack it exhibits after being cured, also referred to herein as “first tack,“ is substantially maintained after being irradiated with gamma radiation.
  • the cured composition exhibits a first tack
  • the cured composition exhibits a second tack of 80 percent or more of the first tack.
  • the cured composition exhibits a second tack of 90 percent or more of the first tack after the cured composition is irradiated with gamma radiation.
  • the cured curable silicone composition defines a first major surface.
  • the first major surface is a surface of the composition that does not directly contact the substrate and is separated from the substrate by a major portion of the composition.
  • the first surface exhibits a first tack, and, after the cured composition is irradiated with gamma radiation, the first surface exhibits a second tack of 80 percent or more of the first tack.
  • the first surface exhibits a second tack of 90 percent or more of the first tack after the cured composition is irradiated with gamma radiation.
  • the gel is cohesive.
  • a cohesive gel does not break apart or leave a significant visible residue when removed from a surface it has been adhered to.
  • the cohesiveness of the gel can be determined by measuring its relative peel strength and/or post-cure penetration hardness.
  • the gel may exhibit a peel strength of 0.20 to 30 newtons per inch (N/in). In other embodiments, it may be preferred that the gel exhibit a peel strength of 1 to 15 newtons per inch.
  • the peel strength of the gel can be measured by forming a 1 -inch- wide test strip of the cured silicone composition on a Mylar® substrate.
  • the Mylar® substrate is coated with the curable silicone composition by applying the composition using a weighted roller using two forward and backward passes. Air bubbles are removed from the coating composition by manually by pressing such bubbles toward the edge of the test area by hand.
  • the coated article is cut by dragging a 1 inch cutting tool, comprising two razor blades mounted one inch apart, across the substrate to form test strips.
  • Each test strip is placed, with the silicone coated side down, onto a 2 x 6 in stainless steel test panel.
  • a digital thickness gauge with a thumb activated lever is used to measure the total thickness of each test strip.
  • Peel strength testing can be performed with a peel/release tester from Cheminstruments or a Shimadzu tensile tester.
  • the peel strength is determined at a rate of 12 in/min or 300 mm/min. and is an average value taken over a stroke of at least 80 mm.
  • the gel may exhibit a post-cure penetration hardness of 25 to 500 1/10 mm measured according to DIN ISO 2137 using a hollow cone of 62.5 grams for 60 seconds after curing for 60 minutes at 120°C.
  • the gel exhibits a post-cure penetration hardness of 150 to 300 1/10 mm measured according to DIN ISO 2137 using a hollow cone of 62.5 grams for 60 seconds after curing for 60 minutes at 120°C.
  • curable silicone composition examples include Examples 1-9, which are described below.
  • components of the curable silicone composition included argan oil and tea tree oil, respectively.
  • the tea tree oil was bought from Sigma- Aldrich, Inc. and the argan oil was bought from Jedwards International, Inc.
  • a curable silicone composition was formed by mixing 10 grams of a part A composition with 10 grams of a part B composition.
  • a part A composition -41 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s was provided.
  • the organopolysiloxane was mixed with -42 grams of a linear, vinyl functional polydimethylsiloxane having a molecular weight of about -76,000 g/mol and a viscosity of between 80,000 and 120,000 mPa s.
  • the part A composition also included -26 grams of additional, lower viscosity, linear, vinyl functional polydimethylsiloxanes, -11 grams of MQ resin, -0.14 grams of a hydrosilylation catalyst containing a platinum-group metal, and -0.32 grams of a hydrosilyation inhibitor.
  • the part B composition was formed by mixing -56 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom, -1 gram of a silicone hydride functional polydimethyl siloxane crosslinker, which has a viscosity of -200 mPa s and a molecular weight of -7600 g/mol, and -48 grams of additional linear, vinyl functional polydimethyl siloxanes.
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack, which is reported as the peak tack, of the cured film was 557 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.80 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy and the tack was remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 276 grams. Also, based on observation, it is believed that the 180° peel strength of the sterilized, cured film was less than half of its pre-sterilization value.
  • Example 1
  • a curable silicone composition was formed by mixing a part A composition with a part B composition.
  • 12 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s was provided.
  • the organopolysiloxane was mixed with 4 grams of a mixture of linear, vinyl functional polydimethylsiloxanes and MQ resin, 8.5 grams of additional MQ resin, 0.02 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.05 grams of a hydrosilyation inhibitor for 5 minutes at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm until a clear homogenous mixture was formed.
  • a SpeedMixer® 0.748 grams of a-tocopherol was added to the clear homogenous mixture and mixed with a Speedmixer at 2000 rpm for 5 minutes.
  • the part B composition was formed by mixing 20.2 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom and 13.0 grams of MQ resin. Mixing the part B composition was conducted for 5 minutes at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 668 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 12.5 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was -650 grams and the 180° peel strength of the sterilized, cured film was -14 N/in.
  • a curable silicone composition was formed by mixing a part A composition with a part B composition.
  • 12 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s was provided.
  • the organopolysiloxane was mixed with 4 grams of a mixture of linear, vinyl functional polydimethylsiloxanes and MQ resin, 0.02 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.05 grams of a hydrosilyation inhibitor.
  • the part A composition was 20.2 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom.
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 263 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.35 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 438 grams and the 180° peel strength of the sterilized, cured film was 0.75 N/in.
  • Example 3
  • a curable silicone composition was formed by mixing 10 grams of a part A composition with 10 grams of a part B composition.
  • part A composition 76.75 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s was provided.
  • the organopolysiloxane was mixed with 15.5 grams of a linear, vinyl functional polydimethylsiloxane having a molecular weight of about -76,000 g/mol and a viscosity of between 80,000 and 120,000 mPa-s.
  • the part A composition also included -17 grams of additional, lower viscosity, linear, vinyl functional polydimethylsiloxanes, -12 grams of MQ resin, 0.13 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.13 grams of a hydrosilyation inhibitor.
  • To form the part A composition 2.5 grams of a solution of 25% tocotrienol in palm oil and 10 grams of Wacker HDK® H18, which is hydrophobic, amorphous silica produced by flame hydrolysis and may also be referred to as a silica dimethyl silyate, was added by mixing all the components with a Speedmixer at 2000 rpm for 5 minutes.
  • the part B composition was formed by mixing 14.7 grams of a linear, vinyl functional polydimethylsiloxane having a molecular weight of about -76,000 g/mol and a viscosity of between 80,000 and 120,000 mPa s, 80.85 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom, and 9.45 grams of a silicone hydride functional polydimethyl siloxane crosslinker, which has a viscosity of -1300 mPa s and a molecular weight of -25,000 g/mol.
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 597 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.75 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 557 grams and the 180° peel strength of the sterilized, cured film was 3.7 N/in.
  • a curable silicone composition was formed by mixing 10 grams of a part A composition with 10 grams of a part B composition.
  • part A composition ⁇ 96 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s was provided.
  • the organopolysiloxane was mixed with -5 grams of a linear, vinyl functional polydimethylsiloxane having a viscosity of 19,000 to 23,000 mPa s and a molecular weight of -42,000 g/mol, -3 grams of MQ resin, 0.13 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.28 grams of a hydrosilyation inhibitor until a homogenous mixture was present. Further, 10 grams of a solution of 75% tocotrienol in palm oil, 20 grams of tea tree oil, and 10 grams of Wacker HDK® H18 was added by mixing all the components with a Speedmixer at 2000 rpm for 5 minutes until the part A compositon was homogenous.
  • the part B composition was formed by mixing -29.1 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -70 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom, and -1 .2 grams of a silicone hydride functional polydimethyl siloxane crosslinker, which has a viscosity of -1 ,300 mPa s and a molecular weight of -25,000 g/mol.
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 454 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.36 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 462 grams and the 180° peel strength of the sterilized, cured film was 0.22 N/in.
  • a curable silicone composition was formed by mixing a part A composition with a part B composition.
  • part A composition 12 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s was provided.
  • the organopolysiloxane was mixed with 4 grams of a mixture of linear, vinyl functional polydimethylsiloxanes and MQ resin, 8.5 grams of additional MQ resin, 0.02 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.05 grams of a hydrosilyation inhibitor for 5 minutes at 23°C and a relative humidity of 55% using a Speed Mixer® at 2000 rpm until a clear homogenous mixture was formed.
  • 0.675 grams of 25% tocotrienol in palm oil solution was added to the clear homogenous mixture and mixed with a Speedmixer at 2000 rpm for 5 minutes.
  • part B composition 20.2 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom was mixed with 13.5 grams of MQ resin using a Speedmixer at 2000 rpm for 5 minutes until the part B compositon was homogenous. Mixing the part A composition and part B composition was conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm. The resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 570 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 9.3 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 672 grams and the 180° peel strength of the sterilized, cured film was 15.5 N/in.
  • a curable silicone composition was formed by mixing 10 grams of a part A composition with 10 grams of a part B composition.
  • part A composition ⁇ 96 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -5 grams of a linear, vinyl functional polydimethylsiloxane having a viscosity of 19,000 to 23,000 mPa s and a molecular weight of -42,000 g/mol, -2 grams of MQ resin, 0.13 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.28 grams of a hydrosilyation inhibitor was provided. Further, an additional 60 grams of MQ resin and 10 grams of Wacker HDK® H18 was added to of the mixture by mixing all the components with a Speedmixer at 2000 rpm for 5 minutes until the part A compositon was homogenous.
  • part B composition To form the part B composition, -29.1 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -70 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom, and ⁇ 1.2 grams of a silicone hydride functional polydimethyl siloxane crosslinker, which has a viscosity of -1300 mPa s and a molecular weight of -25,000 g/mol was provided. To this mixture, 2.5 grams of a solution of 25% tocotrienol in palm oil was added by mixing all the components with a Speedmixer at 2000 rpm for
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 474 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.65 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 400 grams and the 180° peel strength of the sterilized, cured film was 1.27 N/in.
  • a curable silicone composition was formed by mixing 10 grams of a part A composition with 10 grams of a part B composition.
  • part A composition -96 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -5 grams of a linear, vinyl functional polydimethylsiloxane having a viscosity of 19,000 to 23,000 mPa s and a molecular weight of -42,000 g/mol, -2 grams of MQ resin, 0.13 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.28 grams of a hydrosilyation inhibitor was provided. Further, 10 grams of a-tocopherol was added to themixture by mixing all the components with a Speedmixer at 2000 rpm for 5 minutes until the part A compositon was homogenous.
  • part B composition 10 grams of a mixture that comprised -29.1 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -70 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom, and -1 .2 grams of a silicone hydride functional polydimethyl siloxane crosslinker, which has a viscosity of -1 ,300 mPa s and a molecular weight of -25,000 g/mol was provided.
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 358 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.21 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 362 grams and the 180° peel strength of the sterilized, cured film was 0.22 N/in.
  • a curable silicone composition was formed by mixing 10 grams of a part A composition with 10 grams of a part B composition.
  • To form the part A composition ⁇ 96 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -5 grams of a linear, vinyl functional polydimethylsiloxane having a viscosity of 19,000 to 23,000 mPa s and a molecular weight of -42,000 g/mol, -2 grams of MQ resin, 0.13 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.28 grams of a hydrosilyation inhibitor was provided.
  • part B composition -29.1 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -70 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom, and -1.2 grams of a silicone hydride functional polydimethyl siloxane crosslinker, which has a viscosity of -1300 mPa s and a molecular weight of -25,000 g/mol was provided.
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 468 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.34 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 425 grams and the 180° peel strength of the sterilized, cured film was 0.41 N/in.
  • Example 9
  • a curable silicone composition was formed by mixing 10 grams of a part A composition with 10 grams of a part B composition.
  • part A composition ⁇ 96 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -5 grams of a linear, vinyl functional polydimethylsiloxane having a viscosity of 19,000 to 23,000 mPa s and a molecular weight of -42,000 g/mol, -2 grams of MQ resin, 0.13 grams of a hydrosilylation catalyst containing a platinum-group metal, and 0.28 grams of a hydrosilyation inhibitor was provided.
  • part B composition To form the part B composition, -29.1 grams of an organopolysiloxane having two terminal groups, with each terminal group comprising a carbon-carbon multiple bond, a molecular weight of about -16,000 g/mol, and a viscosity of -1 ,000 mPa s, -70 grams of an organopolysiloxane having a molecular weight of about -16,000 g/mol, a viscosity of -1 ,000 mPa s, and one or more groups comprising a silicon atom bonded to a hydrogen atom, and -1.2 grams of a silicone hydride functional polydimethyl siloxane crosslinker, which has a viscosity of -1300 mPa s and a molecular weight of -25,000 g/mol was provided. To this mixture, 30 grams of MQ resin was added by mixing all the components with a Speedmixer at 2000 rpm for 5 minutes until the part A composit
  • part A composition and part B composition were conducted for 30 seconds at 23°C and a relative humidity of 55% using a SpeedMixer® at 2000 rpm.
  • the resulting composition was cast as a film onto a substrate and cured at 120°C for 12 minutes.
  • the tack of the cured curable silicone composition (film) was measured using a TA.XT Plus Texture Analyzer using a TA-57R probe and a TA-303 apparatus.
  • the first tack which is reported as the peak tack, of the cured film was 460 grams.
  • the peel strength of the cured film was measured using a peel/release tester from Cheminstruments. The peel strength of the cured film was determined at a rate of 12 in/min.
  • the 180° peel strength of the cured film was 0.56 N/in for a film 230 micrometers thick.
  • the film was then sterilized by gamma irradiation at 25 kGy. After sterilization, the tack and peel strength were remeasured.
  • the second tack which is also reported as a peak tack, of the irradiated, cured film was 490 grams and the 180° peel strength of the sterilized, cured film was 0.52 N/in.
  • the curable silicone composition exhibits desirable tack performance after being irradiated with gamma radiation.
  • the curable silicone composition exhibits a tack of 80 percent or more of the tack it exhibited after being cured after being irradiated with gamma radiation.
  • the curable silicone composition is stable with respect to the cohesive and adhesive properties it exhibits after being cured and irradiated with gamma radiation.

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  • Chemical Kinetics & Catalysis (AREA)
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  • Polymers & Plastics (AREA)
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Abstract

L'invention concerne une composition de silicone durcissable comprenant un premier organopolysiloxane comportant un ou plusieurs groupes comprenant un atome de silicium lié à un atome d'hydrogène, et un second organopolysiloxane comportant un ou plusieurs groupes comprenant une liaison multiple carbone-carbone. La composition de silicone durcissable comprend également un catalyseur d'hydrosilylation et un premier additif de stabilisation comprenant de la vitamine E ou un dérivé de celle-ci. La composition de silicone durcissable comprend éventuellement un second additif stabilisant. Après durcissement de la composition de silicone durcissable, la composition durcie présente un première pégosité, et après avoir été soumise à un rayonnement gamma, la composition durcie présente une seconde pégosité supérieure ou égale à 80 pour cent de la première pégosité.
PCT/EP2024/081181 2023-11-14 2024-11-05 Composition de silicone durcissable Pending WO2025103813A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160024358A1 (en) * 2013-03-14 2016-01-28 Dow Corning Corporation Conductive Silicone Materials And Uses
US20220119690A1 (en) * 2019-01-23 2022-04-21 Momentive Performance Materials Inc. Addition curable silicone adhesive compositions

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160024358A1 (en) * 2013-03-14 2016-01-28 Dow Corning Corporation Conductive Silicone Materials And Uses
US20220119690A1 (en) * 2019-01-23 2022-04-21 Momentive Performance Materials Inc. Addition curable silicone adhesive compositions

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