Fluorine-free release coating compositions for silicone adhesives and related methods of use

Abstract

Curable, and cured, fluorine-free, silicone adhesive release compositions; release liners comprising, consisting essentially of, or consisting of a substrate having a surface and a curable, and cured, fluorine-free, silicone adhesive release compositions on the substrate surface; and composites comprising, consisting essentially of, or consisting of a silicone adhesive and a release liner comprising a substrate having a surface and a cured, fluorine-free, silicone adhesive release composition on the substrate surface, wherein the adhesive resides on the cured, fluorine-free, silicone adhesive release composition; as well as related methods for their preparation and use.

Description

FLUORINE-FREE RELEASE COATING COMPOSITIONS FOR SILICONE ADHESIVES AND RELATED METHODS OF USEFIELD OF THE INVENTION

[0001] The present invention generally relates to silicone release coating compositions used on release liners in connection with silicone adhesives, in particular silicone pressure sensitive adhesives (PSAs).DETAILED DESCRIPTION OF THE INVENTION

[0002] PSAs are used in a variety of consumer and industrial adhesive products, each designed to provide for adhesion of a PSA (and, if present, any backing material) onto a substrate, with permanent tack, using pressure, and without the need for a solvent or heat, as the PSA does not undergo a liquid to solid phase change. These adhesive products include, among others, tapes and labels, with tapes including single-sided, double-sided and transfer tapes.

[0003] Single-sided tapes may be used for sealing, packaging, and surface protection and include, by way of illustration, wound dressings, packing tapes, electrical tapes, and masking tapes. Double sided tapes may be used for mounting, bonding, splicing and laminating, while transfer tapes may be used in applications that require precise adhesion with minimal visual and physical impact, e.g., electronics assembly.

[0004] The physical structure of single-sided tapes, double-sided tapes and labels are related. Each includes a two-sided backing material, a PSA in the form of a relatively thin layer adhered to one side of the backing material (or both sides, in the case of double-sided tapes), and a release liner comprising a liner material and a release coating thereon or, in certain products, a release coating on the backing material (e.g., when a single-sided tape is wound around a core in a spiral manner). Transfer tapes differ in that they comprise a PSA, again in the form of a thin layer, and a release liner (commonly on both sides of the PSA), but may or may not include a backing (or carrier) material. In each application, the release coating, whether part of a release liner or on the backing material, contacts that portion of the PSA intended to be adhered onto a substrate to protect the PSA from damage or unwanted adhesion prior to use. Upon use, the release layer (or coated backing layer) is separated from the PSA, and the PSA is applied onto the desired substrate.

[0005] The backing material in these tapes may be provided in any shape, but is desirably in the form of a strip having two (first and second) opposing surfaces. This non-adhesive materialdesirably provides strength, flexibility and other desired functional properties (e.g., thermal insulation, electrical conductivity) to the PSA tape. For example, a polymer film, such as polyethylene and polypropylene, may be used as a backing material in general purpose tapes, such as those suitable for sealing packages or for bonding two surfaces together, while polyvinyl chloride may be used as a backing material in electrical tapes due to its insulating properties. Foam may be used as a backing material to provide cushioning and in applications that require gap filling, while paper is useful (e.g., masking tapes) in tapes wherein ease of tearing is desired.

[0006] Labels with PSAs comprise a backing material (e.g., paper or film) with a PSA residing on one side of the backing layer, the PSA desirably comprising a relatively thin layer of uniform thickness protected by a release liner. The backing material used in labels is often pre-printed with information and can be customized for specific applications, e.g., shipping labels, product branding, barcodes, and identification tags. To use, one removes the release liner and presses the exposed PSA (with the backing material adhered thereto) onto a desired surface.

[0007] The release liner used in tapes and labels comprises two layers: a substrate and a release coating. The substrate comprises two flat opposing surfaces, is desirably flexible, and in the case of tapes may be provided in the form of a relatively long strip. A variety of materials may be used for the substrate, including paper or a polymer film, with the latter being desired in applications requiring durability, moisture resistance, and precise release.

[0008] The release coating may be a relatively thin and uniform layer residing on at least one side of the substrate, and is intended to contact the PSA. This coating provides a surface that allows the PSA to separate easily from the release liner, and the composition of the coating is selected based on the particular composition of the PSA to ensure desired performance.

[0009] PSAs are available in a variety of compositions, e.g., rubber, acrylic and silicone PSAs, and are commonly selected based on the intended application and cost. Factors often considered to be relevant to the proper selection of a particular PSA include: low and high-temperature resistance, flexibility, chemical resistance, and whether the PSA is to be applied onto a low-energy surface.

[0010] Rubber PSAs are relatively low-cost, but are not designed to withstand temperatures above about 80°C. Acrylic adhesives, prepared using acrylic polymers, offer relatively higher temperature resistance (e.g., up to about 120°C) and can adhere to certain low energy surfaces. Silicone adhesives, prepared from silicone polymers, are known to provide exceptional low andhigh-temperature (e.g., up to about 250°C) resistance, excellent flexibility, chemical resistance, and strong adhesion to low-energy surfaces, but are relatively costly.

[0011] Materials which exhibit a low-energy surface - a surface on which it can be difficult to form a strong adhesive bond and which may benefit from the use of surface treatments and / or specialized adhesives such as silicone PSAs - may generally be described as exhibiting a surface energy below about 40 mN / m. These materials include by way of illustration and not limitation: polyolefins (e.g., polyethylene (PE); polypropylene (PP)); polytetrafluoroethylene (PTFE); ethylene propylene diene monomer (EPDM); silicone rubber; and metals that are powder coated or chromed.

[0012] Other materials that do not exhibit relatively low surface energy may nevertheless benefit from the use of silicone PSAs, depending on the final use and whether the material interacts with and degrades when in contact with the adhesive. Illustrative of materials with a relatively higher surface energy (at least about 40 mN / m) that may benefit from the use of silicone PSAs include by way of illustration and not limitation: polyvinyl chloride (PVC), particularly PVCs that include additives such as plasticizers which make silicone PSAs a more reliable choice for bonding; polystyrene (PS); polyethylene terephthalate (PET or PETE); polycarbonate (PC); polyurethane (PU); acrylics (e.g., polymethylmethacrylate (PMMA), polyacrylates, and acrylonitrile butadiene styrene) (ABS); rubbers (e.g., natural and synthetic rubbers, such as polyisoprene, styrene-butadiene rubber (SBR), butadiene rubber (BR), neoprene (polychloroprene), anodized aluminum; glass (e g., glass, including glass with an anti-reflective coating); and ceramics with glazed surfaces.

[0013] The relatively strong adhesion provided by silicone PSAs, however, does affect the selection of a release liner, and in particular the release coating thereon. The release liner is a critical component, as it protects the adhesive surface of the PSA, and facilitate its handling, storage, and application. On handling and application, the release liner includes a release coating that covers the PSA adhesive surface and prevents undesired premature bonding, accumulation of contaminants thereon and degradation prior to use, acceptable temperature resistance and dimensional stability, while being able to be readily removed with an appropriate release force from the PSA when desired without leaving residue or compromising the PSA adhesive surface which can result in less than optimal bonding.

[0014] Silicone PSAs require specific types of release liners that can withstand their unique properties, including their ability to strongly adhere to a wide variety of surfaces. Release liners with release coatings that comprise fluoropolymers are commonly used in connection with silicone PSAs, as they are compatible with silicone adhesives, provide a low and stable release force, and are resistant to silicone contamination.

[0015] The present invention comprises various aspects, including curable, and cured, fluorine-free, release coating compositions; release liners comprising, consisting essentially of, or consisting of a substrate having a surface and a curable, or cured, fluorine-free, release coating composition on the substrate surface; and composites (e.g., single-sided and double-sided tapes, labels and transfer tapes) comprising, consisting essentially of, or consisting of a PSA, preferably a silicone PSA, and a release liner comprising a substrate having a surface and a cured, fluorine- free, release coating composition on the substrate surface, wherein the PSA resides on the cured, fluorine-free, release coating composition; as well as related methods for the preparation and use of the curable, and cured, release coating compositions, release liners and composites.

[0016] Advantages of the inventive fluorine-free release coating compositions include, among others, providing a relatively low, consistent and stable removal force when a cured release coating composition in contact with an adhesive, particularly a silicone adhesive, is removed (separated) from the adhesive, even across silicone adhesives having differing relaxation forces or DMT (Derjaguin-Muller-Toporov) moduli (which may more commonly be referred to as “soft” or “hard” silicone adhesives), can be formulated to provide a differential release force useful in double sided and transfer tapes wherein different release forces are desirably present for each side of the coated release liner, and are able to withstand the coating and curing processes used with PSAs, and particularly silicone PSAs, including processes wherein the PSA is directly cast onto the release coating composition, and, importantly, exhibiting a relatively low level of extractables in the cured release coating composition after the release liner is separated from the adhesive.

[0017] In one aspect, the present invention provides curable, fluorine-free, release coating compositions comprising, consisting essentially of, or consisting of, a fluorine-free polymer, a fluorine-free crosslinking agent and a crosslinking catalyst, as well as, optionally, a catalyst inhibitor and / or adhesion promoter.

[0018] The fluorine-free polymers desirably may include fluorine-free vinylmethylsiloxane polymers, and more desirably copolymers which comprise vinylmethylsiloxane, such asvinylmethylsiloxane - di methyl siloxane copolymers, wherein the polymers are tri m ethyl si 1 oxy terminated on at least one terminal end, and preferably those which are trimethyl siloxy terminated on one terminal end and are trimethyl silyl terminated on the other terminal end.

[0019] The fluorine-free vinylmethylsiloxane copolymers include, as their description indicates, at least one vinyl substituent on a monomeric unit, not on a terminal end, e.g., a vinyl silane. Other substituents may be included on the same or on other monomeric unit(s), these other substituents including, by way of example, C1-C8 alkyls, such as methyl, ethyl, octyl, or a phenyl or diphenyl.

[0020] Vinylmethylsiloxane - dimethylsiloxane copolymers useful in certain aspects of the invention may desirably include mole% of vinylmethylsiloxane ranging from about 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8 to about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13. In other aspects, these copolymers may have a mole% of vinylmethylsiloxane desirably ranging from about 1 to about 8, and even more desirably from about 4 to about 8, while in still other aspects these copolymers may have a mole% of vinylmethylsiloxane ranging from about 48 to about 52. Mixtures of vinylmethylsiloxane - dimethylsiloxane copolymers having different mole% of vinylmethylsiloxane also are contemplated by the invention.

[0021] The vinylmethylsiloxane - dimethylsiloxane copolymers also may include a vinyl Eq / kg ranging from about 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10 or 0.11 to about 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 or 6.5. In related aspects, the vinyl Eq / kg in the copolymers desirably ranges from about 0.1 to about 1.5, and more desirably from about 0.5 to about 1.1, while in other aspects the vinyl Eq / kg in the copolymers may range from about 6 to about 6.5. Mixtures of vinylmethylsiloxane - dimethylsiloxane copolymers having different vinyl Eq / kg are contemplated by the invention.

[0022] The vinylmethylsiloxane - dimethylsiloxane copolymers that are trimethylsiloxy terminated on at least one terminal end, and are desirably trimethyl silyl terminated on the other terminal end, may further have the following chemical structure, wherein m and n represent the number of their respective monomeric units:with these copolymers preferably having a molecular weight (MW) ranging from about 10,000 g / mol to 500,000 g / mol.

[0023] Illustrative of fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymers that are trimethyl siloxy terminated on at least one terminal end, and trimethylsilyl terminated on the other terminal end, and which may be included in the inventive release coating compositions alone, or in combination with one or more other fluorine-free polymers, include the following copolymers (a) - (i) which possess certain properties as described herein: (a) mole% of vinylmethylsiloxane of from about 0.8 to about 1.2; vinyl Eq / kg from about 0.11 to about 0.15; molecular weight (MW) of about 12,000 g / mol (12K); viscosity of about 250 to about 350 cSt.; (b) mole% of vinylmethylsiloxane of from about 0.8 to about 1.2; vinyl Eq / kg from about 0.11 to about 0.15; MW of about 23K g / mol; viscosity of about 700 to about 800 cSt.; (c) mole% of vinylmethylsiloxane of from about 0.8 to about 1.2; vinyl Eq / kg from about 0.11 to about 0.15; MW of about 28K g / mol; viscosity of about 800 to about 1200 cSt; (d) mole% of vinylmethylsiloxane of from about 0.3 to about 0.7; vinyl Eq / kg from about 0.04 to about 0.08; MW of about 425K g / mol; viscosity of about 2,000K to about 4,000K cSt.; (e) mole% of vinylmethylsiloxane of from about 4 to about 5; vinyl Eq / kg from about 0.5 to about 0.7; MW of about 28K g / mol; viscosity of about 800 to about 1,200 cSt.; (f) mole% of vinylmethylsiloxane of from about 7 to about 8; vinyl Eq / kg from about 0.9 to about 1.1; MW of about 28K g / mol; viscosity (25°C) of about 800 to about 1,200 cSt.; (g) mole% of vinylmethylsiloxane of from about 11 to about 13; vinyl Eq / kg from about 1.1 to about 1.4; MW of about 225K g / mol; viscosity of about 300K to about 500K cSt.; (h) mole% of vinylmethylsiloxane of from about 48 to about 52; vinyl Eq / kg from about 6 to about 6.5; MW of about 50K g / mol; viscosity of about 4.5K to about 5.5K cSt.; and (i) mole% of vinylmethylsiloxane of from about 0.2 to about 0.3, MW above 50,000 g / mol.

[0024] The invention also contemplates the use of fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymers having a mole% of vinylmethylsiloxane, a vinyl Eq / kg and / or an amount thereof in the release composition, each of the mole% of vinylmethylsiloxane, vinyl Eq / kg, and amount in the release composition being within the described numerical ranges.

[0025] In other aspects of the invention, the fluorine-free polymer may be a fluorine-free vinylmethylsiloxane polymer, more desirably a vinylmethylsiloxane - dimethylsiloxane copolymer, which is dimethylsilyl terminated on at least one terminal end, and more desirablydimethylsiloxane terminated on the other terminal end, and even more desirably having the following structure, wherein m and n represent the number of their respective monomeric units:This copolymer may have a molecular weight (MW) ranging from about 8,000 g / mol to about 10,000 g / mol, and desirably a vinyl equivalent ranging from about 0.3 to about 0.5 Eq / kg.

[0026] Illustrative of fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymers that are hydride terminated on at least one terminal end, and have a hydromethylsilyl ether group on the other terminal end, and which may be included in the release coating compositions alone, or in combination with one or more other polymers, include a 0.8 - 1.2% vinylmethylsiloxane - dimethylsiloxane copolymer, a vinyl Eq / kg from about 0.3 to about 0.5, a MW of about 8,000 to about 10,000 g / mol; and a viscosity of about 150 to about 250 cSt.

[0027] In still other aspects of the invention, the fluorine-free polymer may be a terpolymer comprising vinylmethylsiloxane.

[0028] In this aspect, the terpolymer desirably may be a fluorine-free dimethylsiloxane - vinylmethylsiloxane - (diphenyl)methylsiloxane terpolymer, which may be referred to as a gum, that is trimethyl siloxy terminated on at least one terminal end, and desirably trimethylsilyl terminated on the other terminal end, and more desirably having the following structure, wherein m, n and p represent the number of their respective monomeric units:and even more desirably having a MW exceeding about 500,000 g / mol.

[0029] Illustrative of these fluorine-free terpolymers which may be included in the compositions alone, or in or in combination with one or more different polymers, is a terpolymer comprising about 6-7% diphenylsiloxane and about 0.1 to 0.2% vinylmethylsiloxane).

[0030] In another aspect, the fluorine-free terpolymer comprising vinylmethylsiloxane may be a fluorine-free vinylmethylsiloxane - (ethyl, phenyl or octyl)m ethyl siloxane - dimethyl siloxane terpolymer that is trimethylsiloxy terminated on at least one terminal end, and desirably trimethylsilyl terminated on the other terminal end. Preferably, this terpolymer has the following structure, wherein R is a C1-C8 alkyl or phenyl, and more preferably phenyl or octyl, wherein m, n and p represent the number of their respective repeating monomers:In certain aspects, the terpolymer comprises about 3 - 5%> vinylmethylsiloxane and about 35% to about 40% phenyl (or octyl)methylsiloxane, desirably with a vinyl eq / Kg of about 0.2 to about 0.3. The MW of this terpolymer may range from about 2,000 g / mol to about 15,000 g / mol, and desirably from about 2,500 g / mol to about 12,000 g / mol. More desirably, in the case of the terpolymer comprising phenylmethylsiloxane, the terpolymer may have a molecular weight (MW)ranging from about 2,500 g / mol to about 3,000 g / mol, and in the case of the terpolymer comprising octylmethylsiloxane, the terpolymer may have a molecular weight (MW) ranging from about 10,000 g / mol to about 12,000 g / mol.

[0031] The release coating compositions of the present invention, in addition to the polymers and other components described herein, further include one or more fluorine-free crosslinking agents.

[0032] In one aspect, the crosslinking agent may be a copolymer of an alkylhydrosiloxane and a dialkylsiloxane, more desirably a copolymer of methylhydrosiloxane and dimethylsiloxane, and even more desirably a trimethylsiloxy terminated copolymer, which more desirably is terminated by a trimethyl silyl group at the other terminal end. Preferably, the copolymer has the following structure, wherein m and n represent the number of their respective repeating monomers:

[0033] It was further found desirable to use fluorine-free alkylhydrosiloxane and dialkylsiloxane copolymers which have a relatively low molecular weight (MW), e.g., from about 1,000 g / mol to about 10,000 g / mol, more desirably from about 1,000 g / mol about 6,500 g / mol, and even more desirably from about 1,000 g / mol to about 2,000 g / mol.

[0034] Other aspects of the invention contemplate that the crosslinking agent may be a fluorine-free polymethylhydrosiloxane, desirably trimethylsiloxy terminated on one terminal end, more desirably trimethylsilyl terminated on the other terminal end, and even more desirably having the following structure, wherein n represents the number of repeating monomeric units:preferably with a molecular weight (MW) ranging from about 1,000 g / mol to about 3,000 g / mol, and more preferably from about 1,400 g / mol to about 2,400 g / mol.

[0035] Additional aspects of the invention include a crosslinking agent that is a fluorine-free hydride functional siloxane having the structure:

[0036] Other aspects of the invention may include a crosslinking agent that is a fluorine-free methylhydrosiloxane - octylmethylsiloxane copolymer, desirably being trimethylsiloxy terminated on at least one terminal end, more desirably trimethylsilyl terminated on the other terminal end, and even more desirably having the following structure, wherein m and n represent the number of their respective repeating monomeric units:desirably having a molecular weight (MW) ranging from about 1,000 g / mol to about 3,000 g / mol, and preferably from about 1,600 g / mol to about 2,400 g / mol.

[0037] Illustrative of these fluorine-free hydride functional siloxane crosslinkers which may be included in the release coating compositions alone, or in combination with one or more different crosslinkers, include a 25-30% methylhydrosiloxane-octylmethylsiloxane copolymer.

[0038] Additional aspects of the invention may include a crosslinking agent that is a fluorine- free polyphenyl - (dimethylhydrosiloxy)siloxane, desirably dimethylsilyl terminated on one terminal end, and more desirably dimethylsiloxane terminated on the other terminal end, and even more desirably having the following structure, wherein n represents the number of repeating monomeric units:or, a fluorine-free (45-50%)methylhydrosiloxane - phenylmethylsiloxane copolymer, desirably dimethylsilyl terminated on one terminal end, and more desirably dimethylsiloxane terminated on the other terminal end, and even, and more desirably having the following structure, wherein m and n represent the number of repeating monomeric units:desirably having a molecular weight (MW) of from about 100 g / mol to about 300 g / mol, and more desirably from about 150 g / mol to about 350 g / mol, and even more desirably about 300 g / mol.

[0039] Catalysts also are contemplated as a component in the inventive release coating compositions. This component was found to be useful in assisting the initiation of reactions involving the reactive components in the release coating compositions, such reactions believed to include hydrosilylation. Moreover, these catalysts are fluorine-free, compatible with the other components in the compositions, e.g., some are provided as siloxane complexes, and desirably provide catalytic activity for the inventive release coating compositions at room temperature.

[0040] In certain aspects of the invention, the catalyst for what is believed to be a hydrosilylation reaction occurring in the release coating compositions may comprise a Group VIII to Group XI transition metal. Group VIII transition metals are iron (Fe), ruthenium (Ru), osmium (Os), and hassium (Hs). Group IX transition metals are cobalt (Co), rhodium (Rh), and iridium (Ir); Group X transition metals are nickel (Ni), palladium (Pd), and platinum (Pt); and Group XI transition metals are copper (Cu), silver (Ag), and gold (Au). Combinations thereof, complexes thereof (e g. organometallic complexes), and other forms of such metals, may be utilized as the hydrosilylation reaction catalyst.

[0041] Other aspects of the invention use catalysts for the hydrosilylation reaction which comprise rhenium (Re), molybdenum (Mo), Group IV transition metals (i.e., titanium (Ti), zirconium (Zr), and / or hafnium (Hf)), lanthanides, actinides, and Group I and II metal complexes (e.g. those comprising calcium (Ca), potassium (K), strontium (Sr), etc.). Combinations thereof, complexes thereof (e.g. organometallic complexes), and other forms of such metals, may be utilized as the hydrosilylation reaction catalyst.

[0042] In aspects of the invention, the catalyst may be in any suitable form. For example, the catalyst may be a solid, examples of which include platinum-based catalysts, palladium-based catalysts, and similar noble metal-based catalysts, and also nickel-based catalysts, or as an ingredient in liquid mixture. More specific examples thereof include nickel, palladium, platinum, rhodium, cobalt, and similar elements, and also platinum-palladium, nickel-copper-chromium, nickel-copper-zinc, nickel-tungsten, nickel-molybdenum, and similar catalysts comprising combinations of a plurality of metals. Additional examples of solid catalysts include Cu — Cr, Cu — Zn, Cu — Si, Cu — Fe — Al, Cu — Zn — Ti, and similar copper-containing catalysts, and the like. In certain aspects, such catalysts may further be in or on a solid carrier. Examples of carriers include activated carbons, silicas, aluminas, zeolites and other inorganic powders / particles (e.g. sodium sulphate), and the like. The catalyst may also be disposed in a vehicle, e.g., a solvent which solubilizes the catalyst, alternatively a vehicle which merely carries, but does not solubilize, the catalyst. Such vehicles are known in the art.

[0043] In preferred aspects of the invention, the catalyst comprises platinum. In these embodiments, the catalyst is exemplified by, for example, platinum black, compounds such as chloroplatinic acid, chloroplatinic acid hexahydrate, a reaction product of chloroplatinic acid and a monohydric alcohol, platinum bis(ethylacetoacetate), platinum bi s(acetyl acet onate), platinum chloride, and complexes of such compounds with olefins or organopolysiloxanes, as well as platinum compounds microencapsulated in a matrix or core-shell type compounds. Microencapsulated hydrosilylation catalysts and methods for their preparation are known in the art.

[0044] In related aspects of the invention, complexes of platinum with organopolysiloxanes suitable for use as the catalyst include l,3-diethenyl-l,l,3,3-tetramethyldisiloxane complexes with platinum. These complexes may be microencapsulated in a resin matrix. Alternatively, thehydrosilylation reaction catalyst may comprise l,3-diethenyl-l ,l ,3,3-tetramethyldisiloxane complex with platinum.

[0045] The catalysts are commonly provided in the release coating compositions in an amount or quantity sufficient to promote curing thereof at desired conditions. In the various aspects of the invention this amount may vary, but desirably the amount of catalyst composition in the various release coating compositions as provided by a supplier may range from about 0.01 wt.% to about 0.5 wt.%, desirably from about 0.05 wt.% to about 0.4 wt.%, more desirably from about 0.1 to about 0.3 wt.%, and preferably about 0.2 wt.%, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

[0046] In certain aspects, the inclusion of a catalytic inhibitor in the release coating compositions is desired because the catalysts are highly active even at low concentrations, and control over the catalytic reaction (e.g., hydrosilylation) is desirable to provide one or more of the following advantages: controlling any premature hydrosilylation reaction, minimizing or preventing undesired side reactions, and enhancing yield of the desired cured product.

[0047] Catalytic inhibitors useful in connection with the inventive release compositions also are fluorine-free, compatible with the catalyst and other composition ingredients, and desirably provided in a volatile carrier. Illustrative of inhibitors useful in the release coating compositions include one or more of ethylenically unsaturated amides, aromatically unsaturated amides, acetylenic compounds, ethylenically unsaturated isocyanates, olefinic siloxanes, unsaturated hydrocarbon diesters, unsaturated hydrocarbon mono-esters of unsaturated acids, conjugated ene- ynes, hydroperoxides, ketones, sulfoxides, amines, phosphines, phosphites, nitrites, diaziridines, maleates, and alkynyl alcohols.

[0048] When included, the inhibitor may be present in the release coating composition in an amount suitable to provide the desired reaction rate and other advantages, and desirably may range from about 0.01 to about 3 wt.%, more desirably from about 0. 1 to about 0.5 wt.%, and even more desirably from about 0.1 to about 0.3 wt.%, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

[0049] Aspects of the invention may optionally include an adhesion promoter, which is also fluorine-free. Suitable adhesion promoters are those that provide enhanced bond strength of the cured release coating composition to the substrate relative to a cured release coating composition without such promoter, are compatible with the other ingredients in the release coatingcomposition, and are desirably solvent-free. When included, adhesion promoters are present in relatively low amounts, e.g., from about 0.1 wt.% to about 5 wt.%, and desirably from about 1 wt.% to about 2 wt.%, of the release coating composition.

[0050] One or more of the fluorine-free polymers, fluorine-free crosslinking agents and fluorine-free catalysts, as well as optional ingredients such as, e.g., fluorine-free catalyst inhibitors and adhesion promoters, each as described herein, may be combined to provide the inventive release coating compositions, which compositions may be used to provide inventive cured release coating compositions as well as products, e.g., release liners, tapes and labels, which may advantageously be used with silicone adhesives, in particular, silicone PSAs.

[0051] In developing the inventions described herein, however, it was found that certain combinations of polymers, crosslinking agents, catalysts, and other optional ingredients, and often in certain amounts, were unexpectedly found to provide the resulting cured release coating compositions with certain beneficial properties. These more desirable release coating compositions are described in the following illustrative compositions which, when cured, may be used as a component of release liners, tapes, labels and other products wherein a silicone adhesive requires protection prior to use.

[0052] In a first composition, the fluorine-free release coating composition comprises, consists essentially of, or consists of a fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymer; a fluorine-free crosslinking agent, a fluorine-free catalyst and, optionally, a fluorine-free catalyst inhibitor and / or adhesion promoter, wherein the copolymer is trimethylsiloxy terminated on one terminal end and trimethyl silyl terminated on the other terminal end, desirably having the following structure, wherein m and n represent the number of monomeric unitsand more desirably wherein the copolymer has a ranging from about 10,000 to about 500,000, and even more desirably wherein the mole% of vinylmethylsiloxane ranges from about 4 to about 8 and / or the vinyl Eq / kg ranges from about 0.5 to about 1.1.

[0053] In preferred aspects of the first composition, there may be variations in the specific copolymers and crosslinking agents, as well as in the amounts thereof, as described in the following paragraphs.

[0054] In one preferred aspect of this first composition, the fluorine-free crosslinking agent may be a copolymer of an alkylhydrosiloxane and a dialkylsiloxane, more desirably a copolymer of methylhydrosiloxane and dimethylsiloxane, and is trimethylsiloxy terminated at one terminal end and trimethyl silyl terminated at the other terminal end, desirably having the following chemical structure, wherein m and n represent the number of monomeric units:and more desirably wherein the molecular weight (MW) of the crosslinking agent ranges from about 1,000 to about 10,000, even more desirably from about 1,000 about 6,500 or from about 1,000 to about 2,000.

[0055] In another preferred aspect of this first composition, wherein the crosslinking agent is a copolymer of an alkylhydrosiloxane and a dialkyl siloxane or a more desired species thereof as described herein, the vinylmethylsiloxane - dimethylsiloxane copolymer may be present in the composition at from about 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 wt.% up to about 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84 or 85 wt.%, desirably from about 50 to about 85, more desirably from about 55 to about 80, and even more desirably from about 60 wt.% to about 75 wt.%, and / or the crosslinking agent may be present in the composition at from about 15 wt.% to about 45 wt.%, and more desirably from about 15 wt.% to about 40 wt.%, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

[0056] In another preferred aspect of this first composition, the vinylmethylsiloxane - dimethylsiloxane copolymer has a mole% of vinylmethylsiloxane of from about 4 to about 5 and / or a vinyl Eq / kg from about 0.5 to about 0.7 and / or a MW of about 25K g / mol to about 30K g / mol, and further may be present in the composition at from about 70 wt.% to about 85 wt.% of the composition, and the crosslinking agent is a copolymer of an alkylhydrosiloxane and a dialkylsiloxane, or a more desired species thereof as described herein, and comprises about 10 wt.% to about 30 wt.% of the composition, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

[0057] In yet another preferred aspect of this first composition, the fluorine-free crosslinking agent may have following structure, wherein n represents the number of repeating monomeric unitsand wherein the molecular weight (MW) of the crosslinking agents is from about 1,000 to about 3,000, and desirably from about 1,400 to about 2,400. In this preferred aspect, the crosslinking agent is a copolymer of an alkylhydrosiloxane and a dialkylsiloxane or a more desired species thereof as described herein, and the vinylmethylsiloxane - dimethylsiloxane copolymer desirably may be present in the composition at from about 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 wt.% up to about 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94 or 95 wt.%, desirably from about 75 wt.% to about 95 wt.%, and more desirably from about 85 wt.% to about 95 wt.%, and / or the crosslinking agent may be present in the composition at from about 3 wt.% to about 15 wt.%, and more desirably from about 5 wt.% to about 10 wt.%, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

[0058] In another preferred aspect of the first composition, the fluorine-free crosslinking agent has the following structure:and may comprise about 1 wt.% to about 10 wt.% of the first composition, and wherein the vinylmethylsiloxane - dimethylsiloxane copolymer (including species thereof as described herein) comprises about 60 wt.% to about 80 wt.%, and desirably from 65 wt.% to about 75 wt.%, of the composition, wherein the weight percent is based on the weight of the non-volatile ingredients in the first composition. In a more preferred aspect, this composition may further comprise a second crosslinking agent which is a copolymer of an alkylhydrosiloxane and a dialkylsiloxane, moredesirably a copolymer of methyl hydrosil oxane and dimethylsiloxane, and is tri m ethyl si 1 oxy terminated at one terminal end and trimethyl silyl terminated at the other terminal end, wherein the second crosslinking agent most desirably has a chemical structure as follows, wherein m and n represent the number of monomeric units:and wherein the molecular weight (MW) of the crosslinking agent ranges from about 1,000 g / mol to about 10,000 g / mol, this additional crosslinking agent further and desirably comprising about 5 wt.% to about 35 wt.%, and desirably abut 10 wt.% to about 30 wt.%, of the first composition, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

[0059] In yet another preferred aspect of the first composition, the fluorine-free vinylmethylsiloxane - dimethyl siloxane copolymer may be present in the composition in an amount ranging from about 10 wt.% to about 40 wt.%, the composition may comprise about 30 wt.% to about 85 wt.% of a crosslinking agent that is a copolymer of an alkylhydrosiloxane and a dialkylsiloxane, more desirably a copolymer of methylhydrosiloxane and dimethyl siloxane, and is trimethyl siloxy terminated at one terminal end and trimethyl silyl terminated at the other terminal end, wherein the crosslinking agent most desirably has a chemical structure as follows, wherein m and n represent the number of monomeric units:wherein the molecular weight (MW) of the crosslinking agent ranges from about 1,000 g / mol to about 10,000 g / mol, with the first composition further comprising about 5 wt.% to about 15 wt.% of a second crosslinking agent having the following chemical structure:wherein this crosslinking agent desirably has a molecular weight (MW) of between about 800 g / mol and about 1,000 g / mol.

[0060] In a second composition, the fluorine-free release coating composition comprises, consists essentially of, or consists of: a fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymer; a fluorine-free crosslinking agent, a fluorine-free catalyst and, optionally, a fluorine- free catalyst inhibitor and / or adhesion promoter, wherein the copolymer is dimethylsilyl (- Si(CH3)2H) terminated on one terminal end and dimethylsiloxane (-O-Si(CH3)2H) terminated on the other terminal end, desirably having a vinyl Eq / kg of from about 0.3 to about 0.5, and more desirably a molecular weight (MW) of about 8,000 g / mol to about 10,000 g / mol.

[0061] In preferred aspects of the second composition, there may be variations in the crosslinking agent as described in the following paragraphs.

[0062] In a preferred aspect, the crosslinking agent in the second composition is a fluorine- free polyphenyl - (dimethylhydrosiloxy)siloxane, desirably being dimethylsilyl (-Si(CH3)2H) terminated on one terminal end and dimethylsiloxane (-O-Si(CH3)2H) terminated on the other terminal end, and even more desirably having the following structure, wherein n represents the number of repeating monomeric units:

[0063] In another preferred aspect of the second composition, the crosslinking agent is a fluorine-free methylhydrosiloxane - phenylmethylsiloxane copolymer, desirably being dimethylsilyl (-Si(CH3)2H) terminated on one terminal end and dimethylsiloxane (-O-Si(CH3)2H terminated on the other terminal end, and more desirably having the following structure, wherein m and n represent the number of repeating monomeric units:

[0064] In a third composition, the fluorine-free release coating composition comprises, consists essentially of, or consists of a fluorine-free dimethylsiloxane - vinylmethylsiloxane - (ethyl, phenyl, diphenyl or octyl)methylsiloxy terpolymer, a fluorine-free crosslinking agent, a fluorine-free catalyst and, optionally, a fluorine-free catalyst inhibitor and / or adhesion promoter, wherein the terpolymer is trimethylsiloxy terminated on at least one terminal end, and desirably trimethylsilyl terminated on the other terminal end.

[0065] In preferred aspects of the third composition, there may be variations in the specific terpolymers and crosslinking agent, as well as in the amounts thereof, as described in the following paragraphs.

[0066] In one preferred aspect, the terpolymer is a fluorine-free dimethylsiloxane - vinylmethylsiloxane - (diphenyl)methylsiloxane terpolymer, and desirably comprises about 6-7% diphenylsiloxane and / or about 0.2 to 0.3 mole% vinylmethylsiloxane.

[0067] In another preferred aspect of the third composition, the terpolymer is a fluorine-free vinylmethylsiloxane - (ethyl, phenyl or octyl)methylsiloxane - dimethylsiloxane terpolymer, a fluorine-free crosslinking agent and a fluorine-free crosslinking catalyst, wherein the terpolymer is trimethylsiloxy terminated on at least one terminal end, and desirably trimethylsilyl terminated on the other terminal end, and wherein the terpolymer desirably has the following chemical structure, wherein m, n and p represent the number of monomeric units:and wherein R is a Ci-Cs alkyl or phenyl, and more preferably phenyl or octyl, and more desirably the terpolymer has a MW ranging from about 2,000 g / mol to about 15,000 g / mol, and desirablyfrom about 2,500 g / mol to about 12,000 g / mol, and even more desirably the terpolymer comprises about 3 - 5% vinylmethylsiloxane and about 35% to about 40% phenyl (or octyl)methylsiloxane.

[0068] While the release coating compositions of the present invention are useful in connection with a wide variety of silicone adhesives, particularly silicone PSAs, it was found that release coating compositions comprising fluorine-free vinylmethylsiloxane polymers, and in particular vinylmethylsiloxane - dimethylsiloxane copolymers, and more specifically in compositions comprising at least about 20, 30, 40, 50, 60, 70 or 80 wt.% of such copolymers, exhibited undesirable release properties when included in release liners for relatively soft silicone adhesives such as silicone PSAs, e.g. adhesives with a relatively low relaxation force of no more than about 200g, 180g, 160g, 140g, 120g, 100g, 80g, 60g, 40g, 20g or 10g, down to about 5, 2 or 1 g or, expressed in terms of surface DMT (Derjaguin-Muller-Toporov) modulus, a modulus of no greater than about 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 down to about 1, 0.5 or 0.1 MPa. More specifically, it was discovered that these cured release coatings required a relatively high, and undesirable, force to effect liner release from such relatively soft silicone adhesives, specifically silicone PSAs, when used in the manner contemplated herein.

[0069] It was unexpectedly discovered that the inclusion of fluorine-free vinyl terminated siloxanes in release coating compositions with no or relatively low amounts of vinylmethylsiloxane - dimethylsiloxane copolymers provided desirable release properties from silicone adhesives, including silicone PSAs, and in particular those adhesives that exhibit relatively low relaxation force, e.g., no more than about 200g, 180g, 160g, 140g, 120g, 100g, 80g, 60g, 40g, 20g or 10g down to about 5, 2, or 1 g or, expressed in terms of surface DMT modulus, a modulus of no greater than about 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 down to about 1, 0.5 or 0.1 MPa.

[0070] In a fourth composition, which may be useful with silicone adhesives that exhibit relatively low relaxation force or surface DMT modulus, the fluorine-free release coating compositions comprise, consist essentially of, or consist of: a fluorine-free siloxane, desirably a vinylmethylsiloxane - di methyl siloxane copolymer which is vinyl terminated on at least one terminal end, and desirably on both terminal ends; a crosslinking agent comprising a methylhydrosiloxane — dimethylsiloxane copolymer that is trimethylsiloxane terminated on at least one terminal end, and desirably trilethylsilyl terminated on the other terminal end, and a methylhydrosiloxane — phenylmethylsiloxane copolymer that is dimethylsilyl terminated on one terminal end, and more desirably dimethyl siloxane terminated on the other terminal end; and acatalyst, as well as, optionally, a catalyst inhibitor and / or an adhesion promoter, wherein the composition has from no detectable amount, 0.01, 0.1 or 1 wt.% up to about 2, 3, 4,5, 6, 7, 8, 9, or 10 wt.% of a vinylmethylsiloxane - dimethylsiloxane copolymer that is dimethyl silyl or trimethylsiloxane terminated on at least one terminal end, the weight percentages being based on the total weight of the release composition after removal of all volatiles.

[0071] Illustrative of fluorine-free vinyl terminated siloxanes, which are vinyl terminated on at least one terminal end, and desirably vinyl terminated on each terminal end, that may be used in release coating compositions such as, e.g., the fourth composition, in connection with silicone adhesives having a relatively low relaxation force or surface DMT modulus include one or more of: (a) a dimethylsiloxane having the following structure, wherein n represents the number of repeating monomers:which include a vinyl terminated polydimethylsiloxane; (b) a vinylmethoxysiloxane homopolymer, desirably having a molecular weight (MW) ranging from about 800 g / mol to about 1,000 g / mol, wherein n represents the number of repeating monomers:and / or (c) a (diphenylsiloxane)-dimethylsiloxane copolymer, e.g., vinyl terminated (4-6% diphenylsiloxane)-dimethylsiloxane copolymers, desirably having a molecular weight (MW) of about 60,000 g / mol; vinyl terminated (15-17% diphenylsiloxane)-dimethylsiloxane copolymers, desirably having a molecular weight (MW) ranging from about 8,000 to about 12,000 g / mol, and more desirably about 9,000 to about 10,000g / mol; and / or vinyl terminated (15-17% diphenylsiloxane)dimethylsiloxane copolymers, desirably having a molecular weight (MW) offrom about 75,000 to about 40,000, and more desirably from about 50,000 to about 60,000, wherein m and n represent the number of their respective repeating monomers:

[0072] Desirably, the crosslinking agent in this composition comprises, or consists of, two copolymers. One copolymer is a methylhydrosiloxane — dimethylsiloxane copolymer having the following structure, wherein m and n represent the number of their respective repeating monomers:It was further found desirable that this agent have a relatively low molecular weight (MW), e.g., from about 1,000 g / mol to about 3,000 g / mol, more desirably from about 1,500 g / mol about 2,500 g / mol, and even more desirably from about 1,800 g / mol to about 2,200 g / mol.

[0073] The second copolymer in the crosslinking agent of this composition tis a fluorine-free (45-50%)methylhydrosiloxane - phenylmethylsiloxane copolymer, desirably dimethylsilyl terminated on one terminal end, and more desirably dimethylsiloxane terminated on the other terminal end, and more desirably has the following structure, wherein m and n represent the number of repeating monomeric units:this agent having a MW of from about 100 g / mol to about 300 g / mol, and more desirably from about 150 g / mol to about 350 g / mol, and even more desirably about 300 g / mol. In these compositions that are useful in connection even with relatively soft adhesives, the fluorine-free siloxanes, desirably dimethylsiloxane polymers, which are vinyl terminated on at least oneterminal end, and desirably on both terminal ends, may be present in the release coating compositions in an amount ranging from about 80 wt.% to about 98 wt.%, desirably from about 85 wt.% to about 95, wt.%, more desirably from about 90 wt.% to about 95 wt.%, with a crosslinking agent present in an amount ranging from about 1 to about 15 wt.%, and desirably from about 2 to about 10 wt.%, all weight percents based on the weight of the non-volatile ingredients in the release coating composition.

[0074] More desirably, these compositions comprise or consist of: a diphenylsiloxane — dimethylsiloxane copolymer that is vinyl terminated on each terminal end; a crosslinking agent comprising a methylhydrosiloxane — dimethylsiloxane copolymer that is trimethylsiloxane terminated on one terminal end and trilethylsilyl terminated on the other terminal end and a methylhydrosiloxane — phenylmethylsiloxane copolymer that is dimethylsilyl terminated on one terminal end and dimethylsiloxane terminated on the other terminal end; and a catalyst, as well as, optionally, a catalyst inhibitor and / or an adhesion promoter.

[0075] Even more desirably, the dimethyl siloxane copolymer in these compositions is a diphenyl siloxane — dimethylsiloxane copolymer, and when so included, the fluorine-free release coating compositions comprise, consist essentially of, or consist of: about 80 to about 95 wt.%, desirably from about 85 wt.% to about 95, wt.%, and more desirably from about 90 wt.% to about 95 wt.%, of a diphenylsiloxane — dimethylsiloxane copolymer which is vinyl terminated on at least one terminal end, and desirably on both terminal ends; about 1 to about 10 wt.%, desirably about 1 wt.% to about 5 wt.%, and more desirably about 2 wt.% to about 5 wt.%, of a methylhydrosiloxane — dimethylsiloxane copolymer, trimethylsiloxane terminated on at least one terminal end, and more desirably trilethylsilyl terminated on the other terminal end; about 0.1 wt.% to about 5 wt.%, and desirably about 1 wt.% to about 3 wt.% of a methylhydrosiloxane — phenylmethylsiloxane copolymer that is dimethylsilyl terminated on one terminal end, and more desirably dimethylsiloxane terminated on the other terminal end; and about 0. 1 to about 1 wt.% of a catalyst, as well as, optionally, about 0.1 to about 1 wt.% of a catalyst inhibitor and / or an adhesion promoter, wherein the composition has from no detectable amount, 0.01, 0.1 or 1 wt.% up to about 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt.% of a vinylmethylsiloxane - dimethylsiloxane copolymer that is dimethylsilyl, dimethylsiloxane or trimethylsiloxane terminated on at least one terminal end, with weight percents based on the total weight of the release composition after removal of all volatiles.

[0076] Other aspects of the invention contemplate uncured and cured release coating compositions comprising one or a plurality of non-fluorine-containing crosslinking agents described herein, one or a plurality of non-fluorine-containing vinylmethylsiloxane homopolymers or copolymers with dimethylsiloxane having a mole% of vinylmethylsiloxane, a vinyl Eq / kg and / or amounts in the release composition, each within the numerical ranges described herein therefor, and a catalyst, wherein these compositions may further include one or more of a catalyst inhibitor and an adhesion promotor.

[0077] The release coating compositions may be provided as a solventless composition, a composition diluted by a suitable solvent (e.g., xylene, toluene, hexane, and / or isopropanol), which solvent is desirably volatilized during curing, or as an aqueous emulsion, desirably having from about 20 to about 100 wt.% solids, and may further desirably have a viscosity suitable for the method to be used for applying the release composition onto the substrate, e.g., about 25 centipoise to about 150 centipoise for microgravure coating. The desired viscosity may be provided via the addition of a suitable solvent, with the solvent desirably being a volatile solvent which is volatilized during curing.

[0078] Other aspects of the invention comprise the fluorine-free, release coating compositions described herein that have been cured. Curing may be undertaken via exposing the release coating composition to a heated environment, e.g., an oven, for a few minutes. Typically, about 3 to about 5 minutes at 150°C is sufficient to cure the inventive release coating compositions, although minor alterations in time and temperature may be made to ensure complete curing of the composition.

[0079] In another aspect, there is provided a method for preparing a composite comprising, consisting essentially of, or consisting of a fluorine-free release liner and a silicone adhesive, desirably a PSA, thereon, the method comprising, consisting essentially of, or consisting of (a) providing release liner substrate having a surface; (b) applying a curable, fluorine-free, release coating composition as described herein onto the substrate surface; (c) curing the curable composition to form a cured release coating composition; and (d) coating a silicone adhesive composition, desirably a PSA, onto the cured release composition.

[0080] In related aspects, the composites described herein optionally may include additional treatments or layers to enhance its performance, e.g., polymer coatings for added strength and moisture resistance, and / or anti-static coatings to prevent dust or particles from adhering to thecomposite (e.g., release liners), which is particularly important in electronics or clean room applications.

[0081] The release coating compositions of the present invention may be prepared mixing the copolymers and / or polymers, crosslinking agent, and any optional ingredients, until they are thoroughly mixed, commonly for a few minutes at about 2,000 rpm to about 4,000 rpm, with 3,000 rpm being preferred. Thereafter, the catalyst is added (and, if desired, the catalyst inhibitor), and the resulting combination is mixed for a few minutes at about 2,000 rpm to about 4,000 rpm, with 3,000 rpm being preferred. The catalyzed mixture may then be coated onto a substrate, and subsequently heated in an oven set at a temperature of from about 140°C to about 160°C for several minutes to cure the release coating composition, this cured release coating composition on a substrate constituting what may be referred to as a release liner. The cured release coating composition becomes adhered to the substrate, and remains so adhered when the release liner is removed from a silicone PSA.

[0082] The release coating composition may be applied onto a desired substrate by any conventional technique known in the coating art, such as, roller coating, curtain coating, brushing, spraying, reverse roll coating, doctor knife, dipping, die coating, and offset gravure techniques, with microgravure being desirably used because it is capable of providing a uniform, smooth and relatively thin release coating on the substrate, which results in the cured composition having a substantially uniform thickness across the surface area of the substrate.

[0083] The amount of the release coating composition applied onto the various substrates may vary depending upon the characteristics of the substrate, the properties desired in the cured release coating composition, the composition of the silicone adhesive to be applied on the cured release coating composition, and the particular formulation of the release coating composition. For economic reasons, it is normally desired to apply the least amount of coating composition required to obtain the desired result. It has been found that application of a release coating composition to a thickness that yields a cured release coating thickness of from about 0.1 pm to about 10 pm, from about 1 pm to about 5 pm, or from about 2 pm to about 4 pm, provides acceptable release force properties relative to silicone PSAs. From a weight perspective, the applied release coating composition weights may, depending on the substrate and intended use, vary over a wide range but typically range from about 0.1 to about 10 or more grams per square meter (g / m2), or about 0.5 g / m2to about 5 g / m2, or about 1 g / m2to about 4 g / m2, after curing.

[0084] A variety of substrates may be coated with the inventive release coating compositions to provide a release liner for use with silicone adhesives. For example, the release coating compositions of the present invention may be employed to provide cured release coating compositions (which also may be referred to as a release coating) on primed or unprimed substrates such as paper, vinyl, polyvinyl chloride films, polyester films, polyolefin films (e.g., polyethylene, such as polyethylene terephthalate), polyisobutylene, polymethylpentene, polypropylene (such as biaxially oriented polypropylene (BOPP)), non-woven fabrics, glass, steel, aluminum, etc. Included among the types of paper which can be used are uncoated paper, clay coated paper, glassine, polymer coated paper, paperboard from straw, bark, wood, cotton, flax, cornstalks, sugarcane, bagasse, bamboo, hemp, and similar cellulose materials. These same relatively thin materials that have not been coated with the inventive release coating composition may be used in aspects of the invention in which they contact, but are not separated from, the silicone adhesive upon use, e.g., single-sided tapes.

[0085] The silicone adhesive compositions contemplated for use in connection with aspects of the invention include those that are curable, desirably with the use of platinum or peroxide cure systems. Such adhesives possess relatively high adhesion (commonly comprising polydimethyl siloxane gums) and and may be dispersed in a hydrocarbon, e.g., xylene (about 50 - 60% solids), and desirably cure at relatively low temperatures (e.g., about 100°C in a few minutes).

[0086] After curing, these adhesives are useful as PSAs, and are commonly used in the preparation of tapes, transfer tapes, labels and other products.

[0087] For purposes of the present invention, the silicone adhesives, such as silicone PSAs, may be categorized based on their relaxation force. Generally, the relaxation force provides an indication as to the extent to which an adhesive relaxes, or loses resistance, after an initial deformation. A silicone adhesive with a relatively high relaxation force (at least about 220g, 240g, 260g, 280g, 300g, 320g, 340g, 360g, 380g, 400g, 420g, or 440g) may be thought of as a hard, or more rigid, adhesive, while an adhesive with a relatively lower relaxation force (no more than about 200g, 180, g 160g, 140g, 120g, 100g, 80g, 60g, 40g, 20g, or 10g) may be thought of as a soft adhesive.

[0088] Another means of assessing the relative “harness” or “softness” of silicone PSAs was found to be via an assessment of its surface DMT modulus using Atomic Force Microscopy Quantitative Nanomechanical Mapping (AFM QNM). A relatively “hard” silicone adhesive mayhave a modulus of at least about 70, , 80, 90 100, 150 or 200 up to about 300M, while a relatively soft silicone adhesive may have a modulus of no greater than about 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 down to about 1, 0.5 or 0.1 MPa.

[0089] The methods of preparing and curing each type of silicon adhesive system are well known in the art, and as such are only generally described herein.

[0090] For a platinum cure system, the platinum catalyst is added to the silicone adhesive and mixed thoroughly, with the adhesive mixture being applied onto a cured release coating composition (the latter as part of a release liner) within several hours after the addition of the platinum. The adhesive may then be cured in an over for a few minutes at a relatively high temperature, e.g., 80°C to 150°C.

[0091] For a peroxide cure adhesive, the adhesive is applied onto a cured release coating composition (the latter as part of a release liner), and any solvent in the adhesive is removed via exposure to relatively high temperatures, e.g., about 65°C to about 93°C, leaving a tacky uniform fdm on the cured release coating composition. This film is desirably further cured at a relatively higher temperature (e.g., a few minutes at 175°C to about 200°C) to develop the cohesive strength of the adhesive, providing a finished PSA.

[0092] The silicone adhesives may be applied onto the release liner coating composition after the latter has cured, using any known method, such as roller coating, curtain coating, brushing, spraying, reverse roll coating, doctor knife, dipping, die coating, and offset gravure techniques.

[0093] The release coating compositions described herein, when cured on a substrate to provide a release liner, may be used to provide various adhesive products, such as tapes and labels, the tapes including single-sided, double-sided and transfer tapes. These products may be described as composites, comprising a plurality of layers of materials and compositions.

[0094] In one aspect, a single-sided tape comprises, consists essentially of, or consists of (a) a backing material having two (e.g., first and second) opposing surfaces (the backing material desirably exhibiting strength, flexibility and / or other desirable properties, e.g., thermal insulation, electrical conductivity or insulation); (b) a cured fluorine-free, release coating composition (any of the compositions described herein) on one (e.g., a first) surface of the backing material; and (c) a silicone adhesive composition, desirably a PSA, on the second opposing surface of the backing material. This configuration may be used when the single-sided tape is wound about a central core (e.g., an adhesive tape roll) for ease of storage, unrolling and use, and is designed to prevent theadhesive from undesirably strong adhesion to the uncoated side of the material, thereby adversely affecting the desired use of the tape.

[0095] In a related aspect, a single-sided tape may comprise, consists essentially of, or consist of: (a) a release liner comprising, consisting essentially of, or comprising: (i) a substrate having at least one surface, and desirably two (e g., first and second) surfaces and (ii) a cured fluorine-free, release coating composition (any of the compositions described herein) on the (first) substrate surface; (b) a backing material having a least one surface; and (c) a silicone adhesive composition, desirably a PSA, on the surface of the backing material, wherein the cured release coating composition of the release liner contacts the silicone adhesive. This configuration provides protection for the adhesive prior to use, and permits ease of release liner removal and exposure of the silicone adhesive when desired.

[0096] Another aspect of the present invention provides a double sided tape which comprises, consists essentially of, or consists of: (a) a backing material comprising two opposing surfaces; (b) the same (symmetric) or different (asymmetric) silicone adhesive, desirably as PSA, on each surface of the backing layer; and (c) a release liner comprising, consisting essentially of, or comprising: (i) a substrate having at least one surface and (ii) a cured, fluorine-free, release coating composition (any of the compositions described herein) on the substrate surface, wherein the coating composition of the release liner contacts the silicone adhesive. For double-sided tapes, two distinct release liners, each with a release coating (any of the compositions described herein) on at least one surface of the release liner substrate, may be used to contact the silicone adhesive on each side of the backing layer.

[0097] In yet another aspect, the invention provides a transfer tape. The transfer tape comprises, consists essentially of, or consists of: (a) two release liners, each comprising, consisting essentially of, or comprising: (i) a substrate having at least one surface and (ii) a cured, fluorine- free, release coating composition (any of the compositions described herein) on the substrate surface; and (b) a silicone adhesive, desirably as PSA, having two (e.g., first and second) opposing surfaces, wherein each opposing surface of the adhesive contacts the cured release coating of a release liner. The transfer tape may, or may not, include a carrier material for the adhesive. The release liners provide protection for the adhesives prior to use, and permits ease of release liner removal and exposure of the silicone adhesives when desired.

[0098] A label constitutes another aspect of the invention. The label may comprise, consist essentially of, or consist of: (a) a backing material, e.g., paper or polymer film, having two opposing surfaces, with pre-printing on one surface; (b) a silicone adhesive composition, desirably a PSA, on the second opposing surface of the backing material; and (c) a release liner comprising, consisting essentially of, or comprising: (i) a substrate having at least one surface and (ii) a cured, fluorine-free, release coating composition (any of the compositions described herein) on the substrate surface, wherein the silicone adhesive contacts the cured release coating of the release liner. The release liner provides protection for the adhesive prior to use, and permits ease of release liner removal and exposure of the silicone adhesives when a user desires to adhere the label onto a surface.

[0099] In the release liners, the release coating composition, upon curing, adheres preferentially to the release liner substrate as opposed to the silicone adhesive, and provide various advantages, including those described herein.

[0100] The invention contemplate that each of the ingredients included in the inventive release coating compositions, and desirably the composites prepared using those compositions, are fluorine-free. Fluorine-free means, relative to an ingredient, that the ingredient does not contain fluorine and, relative to a release coating composition or composite, that each ingredient or component used therein does not contain fluorine. Confirmation that an ingredient, composition or composite does not contain fluorine may be obtained via any conventional methodology known to those skilled in the art.

[0101] Tables 1 and 2 provide a series of illustrative fluorine-free release coating compositions in accordance with the present invention.

[0102] The composition in Table 2 were unexpectedly found to be useful as release coating compositions for silicone adhesives that possess a relatively low relaxation force or surface DMT modulus.

[0103] The inventive release coating compositions desirably provide for retention of the silicone adhesive on the cured release coating prior to application of the adhesive onto a desired surface, while also providing for, upon use, release of the release liner (including the release coating composition thereon) from the silicone PSA with relatively low force.

[0104] More desirably, the release coating compositions, after curing, also exhibit a relatively low percentage of extractables. As will be apparent from the description provided herein, release liner coating compositions may comprise an ingredient with one or more vinyl functionalities and a crosslinking agent. A measurement of extractables may be used to assist in an evaluation of the extent to which the vinyl-containing ingredients and crosslinking agent have reacted, with a relatively high extent of such reaction being preferred. Relatively high levels of extractables are typically, but not always, indicative of relatively low level of, and undesirable, crosslinking reactions in the liner coating composition.

[0105] The release force and extractables referenced herein were determined by the methodologies described in the Example.

[0106] Acceptable release force values for the separation of the release liner from the cured silicone adhesive can vary in accordance with the desired application. Generally, however, using the methodology described herein, the release force required to separate the release liner from acured silicone adhesive should not exceed 200 gram / 2 inch (g / 2 in), more desirably should not exceed 150, 125, 100, 75 or 50 gram / 2 inch. Generally, the force may desirably range from about 1 gram / 2 inch to about 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 gram / 2 inch.

[0107] For a product having two release liners, e.g., a transfer tape, it is desired to have a release force for the relatively “tight” release liner (i.e., the liner that exhibits the highest release force) that is approximately three times the release force of the relatively “easy” release liner (i.e., the liner that requires the lowest release force). In other words, and by way of example, the release force for the ’’tight” liner may be about 50 g / 2in, while the release force for the relatively “easy” liner may be about 17 g / 2in. It should be understood, however, that this 3: 1 ratio is approximate and may vary depending on the specific adhesive and coating composition used.

[0108] The extractables for all of the inventive cured release coatings of the invention should be as low as possible, with no detectable extractables being optimal. Generally, using the methodology described herein, the extractables desirably range from not detectable (based on the limit of detection) or 0.01, 0.02, 0.03, 0.04 or 0.05% loss to less than about 2, 1.5, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2 or 0.1 % loss.EXAMPLE

[0109] The various aspects of the present invention are further illustrated by the following example. This example, while providing, in part, details on various aspects of the invention, is illustrative and should not be construed as limiting the scope of the invention.Preparation of the Release Liner Using the Release Coating Composition

[0110] The copolymers and any polymers, crosslinking agent, catalyst inhibitor, and any optional ingredients were added to a mixing vessel, and mixed at 3,000 rpm for 1 minute. A catalyst composition was added thereto, with the mixture again being mixed at 3,000 rpm for 1 minute. Thereafter, and within 12 hrs, the release composition was coated onto a substrate (i.e., Melinex® D316 (2 mil PET, primed, available from DuPont Teijin Films) as follows.

[0111] For coatings identified in the examples as “thick,” an Accu-lab drawdown machine was used to apply the release composition onto a substrate, with the cured release composition thickness varying from 3 pm to 10 pm as measured using a Mitutoyo Absolute Digital Thickness Gage.

[0112] For coatings identified in the examples as “thin,” a Hand Ink Proofer was used to apply the release composition onto a substrate, with the cured release composition thickness varying from 1.5 pm to 3 pm as measured using a Mitutoyo Absolute Digital Thickness Gage.

[0113] The release composition was then cured by subjecting the coated substrate to heat, i.e., in an oven, for 5 mins at 150°C (oven temperature setting).Preparation of the Silicone Adhesive

[0114] Platinum-cure Silicone Adhesive A: a silicone adhesive (71.3g), toluene (18.6g) and a composition containing platinum ((0.05g)) were introduced into a mixing vessel, and then mixed at 3,000 rpm for 2 min using Speed Mixer from Flack Tek (Landrum, South Carolina) to obtain Silicone Adhesive A.

[0115] Peroxide-cure Silicone Adhesive B: a silicone adhesive (34.4g), toluene (16.1g) and Benzoyl Peroxide (0.57g) were introduced into a mixing vessel, and then mixed at 3,000 rpm for 2 min Speed Mixer from Flack Tek (Landrum, South Carolina) to obtain Silicone Adhesive B.Preparation of a Composite

[0116] After preparation as described above, a silicone adhesive (Silicone Adhesive A or B) was coated on the Release Liner (i.e., the substrate with the cured release coating composition thereon) using a knife-over-roll down coater (e.g., Chemlnstruments Laboratory Drawdown Coater) and, after coating, was baked in an oven set at 65°C for 3 minutes, and then at 150°C for 5 min, to cure the silicone adhesive. After baking, a 2 mil PET fdm was applied onto the cured adhesive to provide a composite comprising the Release Liner, adhesive and PET film. The thickness of the cured adhesive ranged from 3 to 4 mils, as measured by a Mitutoyo Absolute Digital Thickness Gage.Assessment of Liner Release

[0117] The assessment of the force required to effect the release of the Release Liner from the silicone adhesive was performed as follows.

[0118] A 2 inch x 10 inch section of each composite was mounted onto a TMI Lab Master® Release & Adhesion Tester (New Castle, Delaware) set at 300 inches / minute at 180 degrees, and subjected to testing. The test provided the force (in ounces, converted to grams) required to separate the Release Liner from the silicone adhesive. The force required for each Release Liner / silicone adhesive run was recorded, and if more than one run (n) was conducted a (numerical) average force was calculated, using the force required to displace the 2 inch wide linerfrom the silicone adhesive (the units of force being grams / 2 inch) determined starting at 1 inch from the starting edge of the sample (i.e., after the first inch of the sample has been displaced) and ending at 5 inches from the starting edge of the sample, as this assists in obtaining a relatively uniform force assessment. The testing was carried out in a controlled temperature (70°F) and humidity (50% RH) environment.Relaxation Force

[0119] The protocol for determining the relaxation force (which provides insight into the ability of the adhesive to flow after an initial force is applied) as well as peak force (which provides insight into the adhesive’s initial mechanical resistance) and % loss (which is the percentage reduction from peak force to the relaxation force) is as follows.

[0120] A texture analyzer was used to determine the foregoing force parameters. After the adhesive is cured, a probe, which is part of the texture analyzer, was moved into contact with the adhesive and force applied, with the maximum force encountered as the probe penetrates the adhesive being recorded as the peak force. After reaching peak force, the probe is held at a specific depth, and the adhesive is allowed to relax, and the force is then recorded as the relaxation force.

[0121] The following table (Table 3) provides data for peak force (grams), relaxation force (grams) and % loss, for several silicone adhesives.A: a peroxi de-cured silicone adhesive B: a platinum-cured silicone adhesive C: a platinum-cured silicone adhesive D: a platinum-cured silicone adhesive E: a silicone gel adhesiveAssessment of Extractables from the Cured Release Composition

[0122] The amount of extractables, as a % loss, from a cured release coating compositions was assessed as follows. A release liner, comprising the release liner substrate and cured release coating composition thereon, was weighed using an X-streme 8000 available from Oxford Instruments (Abingdon, UK) before and after soaking in methyl isobutyl ketone (i.e., 4- methylpentan-2-one, or MZBK) for 30 minutes. The extractables, presented as % loss, for each release liner so tested was calculated as follows: % loss = [(Coat weight before soak) - (Coat weight after soak)]*100 / (Coat weight before soak).

[0123] The data set forth in Tables 4 A and 4B report on the force required to separate release liners comprising various substrates and cured release coating compositions from cured Silicone Adhesive A, and extractables, for certain cured release coating compositions.

[0124] The ingredients used to prepare the release coating compositions are provided in Tables 4A (“thick” cured release coatings) and Table 4B (“thin” cured release coatings), with the release liners, and the Silicone Adhesive A, being prepared and tested in the manner described in this section. The release force results associated with the “thick” coatings may be considered as due to the relatively significant variation in thickness of the “thick” cured release composition as compared to the relatively lower variation in thickness of the “thin” cured release composition.

[0125] The ingredients referenced in Tables 4A, 4B, and 5 are as follows: PolymersA: a vinylmethylsiloxane - dimethyl siloxane copolymer, trimethylsiloxy terminated B: a vinylmethylsiloxane - dimethylsiloxane copolymer, trimethylsiloxy terminated C: a vinyl terminated polyvinylmethylsiloxane homopolymerD: a vinyl terminated (diphenyl siloxane) - dimethylsiloxane copolymer E: a vinyl terminated (diphenyl siloxane) - dimethylsiloxane copolymer F: a vinyl terminated (diphenyl siloxane) - dimethylsiloxane copolymer G: a vinyl terminated polydimethylsiloxaneH: a vinyl terminated polydimethylsiloxaneI: a vinyl terminated polydimethylsiloxaneCrosslinking AgentsJ: a methylhydrosiloxane - dimethylsiloxane copolymer, trimethylsiloxane terminated K: a methylhydrosiloxane - dimethylsiloxane copolymer, trimethyl siloxane terminatedL: a methylhydrosiloxane - dimethylsiloxane copolymer, trimethylsiloxy terminated, hydride functionalM: a methylhydrosiloxane - dimethyl-siloxane copolymer, trimethylsiloxy terminated, hydride functionalN: a polymethylhydrosiloxane, trimethylsiloxy terminatedO: a hydride Q resinP: a hydride Q resinQ: a methylhydrosiloxane - dimethyl siloxane copolymer, trimethylsiloxane terminatedAdhesion PromoterR: adhesion promoterCatalystS: platinum catalystCatalytic InhibitorsT : alkynyl alcoholU: dimethyl maleate

[0126] Referring to Tables 4A and 4B, it was surprisingly found that liners coated with certain fluorine-free release coating compositions were able to provide release from a silicone adhesive (PSA) with relatively low, and desirable, levels of force. For example, experiments wherein the liner release force is below 200 g / 2 inch are most desirable for many applications, with lower liner release forces being more desirable, e.g., less than 150, less than 100, less than 50, and less than 30, and less than 20 g / 2 inch.

[0127] As comparators, Adhesive A was applied onto commercially-available substrates (Hostaphan® 2PRKN, a one-side silicone-coated PET film available from Mitsubishi Chemical; SILPHAN S50 M1R13007, a silicone-coated PET film available from Siliconature), cured, and subjected to the liner release force test as described herein. The liner release force required for removal of the adhesive from each substrate (n=l) was unacceptable, i.e., >1500 g / 2 inch.

[0128] Release coating compositions described in the following Table 5 were prepared and the liner release force associated with these cured release coating compositions (a “thin” coating) was assessed relative to cured Silicone Adhesive A, all in accordance with the methods described in this Example. The results are provided in Table 5.

[0129] This table demonstrates that release compositions prepared using various amounts of vinyl terminated polydimethyl siloxanes (G, H and I) as the sole cross-linkable polymer, and a methylhydrosiloxane and dimethylsiloxane (trimethylsiloxy and trimethyl silyl terminated) as a crosslinking agent, failed to provide a cured release coating composition that could be removed from Silicone Adhesive A with a relatively low force. These vinyl terminated polydimethylsiloxanes, vinyl terminated on each terminal end of the polymer, have the following structure, but differ, at least, in MW, wherein n represents the number of repeating monomeric units:

[0130] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0131] The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “illustrative,” “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0132] The weight percent of the ingredients or components in the compositions described herein should be understood to be based on the total weight of the composition after the removal of any volatile ingredients (e.g., toluene, xylene, acetone) from the composition, unless contradicted by express language or context.

[0133] Although preferred aspects of this invention are described herein, variations of those preferred aspects s may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

We claim:

1. A tape comprising:(a) a backing material comprising first and second opposing surfaces;(b) a silicone adhesive composition on the first surface of the backing material;(c) a release liner comprising a substrate and a fluorine-free cured release coating on the substrate, wherein the fluorine-free cured release coating is prepared from a composition comprising: a fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymer, a fluorine-free crosslinking agent and a fluorine-free crosslinking catalyst, wherein the fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymer has the following structure, wherein m and n represent the number of monomeric units:wherein the copolymer has a molecular weight ranging from about 10,000 to about 500,000 g / mol, and wherein the fluorine-free cured release coating is in contact with the silicone adhesive composition.

2. The tape of claim 1, wherein the crosslinking agent comprises copolymer of an alkylhydrosiloxane and a dialkylsiloxane.

3. The tape of claim 2, wherein the crosslinking agent has the following structure, wherein m and n represent the number of monomeric units:and wherein the molecular weight of the crosslinking agent ranges from about 1,000 to about 10,000 g / mol.

4. The tape of claim 3, wherein and the the vinylmethyl siloxane - dimethylsiloxane copolymer is present in the composition at from about 45 to about 85 wt.% and the crosslinking agent is present in the composition at from about 15 wt.% to about 45 wt.%, wherein the weight percents are based on the weight of the non-volatile ingredients in the composition.

5. The tape of claim 2, wherein the crosslinking agent comprise a fluorine-free polymethylhydrosiloxane having the following structure, wherein n represents the number of repeating monomeric unitsand wherein the molecular weight of the crosslinking agent is from about 1,000 to about 3,000.

6. The tape of claim 5, wherein the crosslinking agent is present in the composition at from about 3 wt.% to about 15 wt.%, wherein the weight percent is based on the weight of the nonvolatile ingredients in the composition.

7. The tape of claim 1, wherein the crosslinking agent has the following chemical structure:

8. The tape of claim 1, wherein the extractables from the cured release composition are no greater than about 2% loss.

9. The tape of claim 1 , wherein the force required to separate the cured release composition from the cured silicone adhesive does not exceed about 200 gram / 2 inch.

10. The tape of claim 1 further comprising a second silicone adhesive composition on the second surface of the backing material and a second release liner comprising a substrate and a fluorine-free cured release coating on the substrate, wherein the fluorine-free cured release coating is prepared from a composition comprising: a fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymer, a fluorine-free crosslinking agent and a fluorine-free crosslinking catalyst, wherein the fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymer has the following structure, wherein m and n represent the number of monomeric units:wherein the copolymer has a molecular weight ranging from about 10,000 to about 500,000 g / mol, and wherein the cured release coating on the second release liner contacts the silicone adhesive on the second surface of the backing material.

11. The tape of claim 10, wherein the silicone adhesives on the backing layer are selected to provide an asymmetric double-sided tape.

12. A tape compri sing :(a) a backing material comprising first and second opposing surfaces;(b) a silicone adhesive composition on the first surface of the backing material;(c) a release liner comprising a substrate and a fluorine-free cured release coating on the substrate, wherein the fluorine-free cured release coating is prepared from a composition comprising: a vinyl terminated (diphenyl siloxane)-dimethylsiloxane copolymer, a fluorine-free crosslinking agent and a fluorine-free catalyst, and wherein the fluorine-free cured release coating is in contact with the silicone adhesive composition.

13. The tape of claim 12, wherein the surface DMT modulus of the silicone adhesive is no greater than about 50 MPa.

14. The tape of claim 12, wherein the molecular weight of the vinyl terminated (diphenyl siloxane)-dimethyl siloxane copolymer ranges from about 8,000 to about 12,000 g / mol.

15. The tape of claim 12, wherein the crosslinking agent is a methylhydrosiloxane — dimethylsiloxane copolymer having the following structure, wherein m and n represent the number of their respective repeating monomers:and a molecular weight ranging from about 1,000 g / mol to about 3,000 g / mol.

16. The tape of claim 15, further comprising a second fluorine-free crosslinking agent comprising a methylhydrosiloxane - phenylmethylsiloxane copolymer having the following structure, wherein m and n represent the number of repeating monomeric units:and a molecular weight of from about 100 g / mol to about 300 g / mol.

17. The tape of claim 12, wherein the composition comprises no more than about 10 wt.% of a vinylmethylsiloxane - dimethylsiloxane copolymer that is dimethylsilyl, dimethylsiloxane or trimethylsiloxane terminated on at least one terminal end, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

18. The tape of claim 12, further comprising a second silicone adhesive composition on the second surface of the backing material and a second release liner comprising a substrateand a fluorine-free cured release coating on the substrate, wherein the fluorine-free cured release coating is prepared from a composition comprising a vinyl terminated (diphenyl siloxane)- dimethylsiloxane copolymer, a fluorine-free crosslinking agent and a fluorine-free catalyst, and wherein the cured release coating on the second release liner contacts the second silicone adhesive on the second surface of the backing material.

19. The tape of claim 18, wherein the surface DMT modulus of the second silicone adhesive is no greater than about 50 MPa.

20. The tape of claim 19, wherein the silicone adhesives on the backing layer are selected to provide an asymmetric double-sided tape.

21. A tape compri sing :(a) a silicone adhesive composition comprising first and second opposing surfaces;(b) first and second release liners each comprising a substrate and a fluorine-free cured release coating on the substrate, wherein the fluorine-free cured release coating is prepared from a composition comprising: a fluorine-free vinylmethyl siloxane - dimethylsiloxane copolymer, a fluorine-free crosslinking agent and a fluorine-free crosslinking catalyst, wherein the fluorine-free vinylmethylsiloxane - dimethylsiloxane copolymer has the following structure, wherein m and n represent the number of monomeric units:wherein the copolymer has a molecular weight ranging from about 10,000 to about 500,000 g / mol, and wherein the fluorine-free cured release coating of the first release liner is in contact with the first surface of the silicone adhesive composition and the fluorine-free cured release coating of the second release liner is in contact with the second surface of the silicone adhesive composition.

22. The tape of claim 21 , wherein the crosslinking agent comprises copolymer of an alkylhydrosiloxane and a dialkylsiloxane.

23. The tape of claim 22, wherein the crosslinking agent has the following structure, wherein m and n represent the number of monomeric units:and wherein the molecular weight of the crosslinking agent ranges from about 1,000 to about 10,000 g / mol.

24. The tape of claim 23, wherein and the the vinylmethylsiloxane - dimethylsiloxane copolymer is present in the composition at from about 45 to about 85 wt.% and the crosslinking agent is present in the composition at from about 15 wt.% to about 45 wt.%, wherein the weight percents are based on the weight of the non-volatile ingredients in the composition.

25. The tape of claim 22, wherein the crosslinking agent comprise a fluorine-free polymethylhydrosiloxane having the following structure, wherein n represents the number of repeating monomeric unitsand wherein the molecular weight of the crosslinking agent is from about 1,000 to about 3,000.

26. The tape of claim 25, wherein the crosslinking agent is present in the composition at from about 3 wt.% to about 15 wt.%, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

27. The tape of claim 21 , wherein the crosslinking agent has the following chemical structure:

28. The tape of claim 21, wherein the extractables from the cured release composition are no greater than about 2% loss.

29. The tape of claim 21 further comprising a carrier material.

30. A tape compri sing :(a) a silicone adhesive composition comprising first and second opposing surfaces;(b) first and second release liners each comprising a substrate and a fluorine-free cured release coating on the substrate, wherein the fluorine-free cured release coating is prepared from a composition comprising: a vinyl terminated (diphenyl siloxane)-dimethylsiloxane copolymer, a fluorine-free crosslinking agent and a fluorine-free catalyst, wherein the fluorine-free cured release coating of the first release liner is in contact with the first surface of the silicone adhesive composition and the fluorine-free cured release coating of the second release liner is in contact with the second surface of the silicone adhesive composition.

31. The tape of claim 30 further comprising a carrier material.

32. The tape of claim 30, wherein the surface DMT modulus of the silicone adhesive is no greater than about 50 MPa.

33. The tape of claim 30, wherein the molecular weight of the vinyl terminated (diphenyl siloxane)-dimethyl siloxane copolymer ranges from about 8,000 to about 12,000 g / mol.

34. The tape of claim 30, wherein the crosslinking agent is a methylhydrosiloxane — dimethylsiloxane copolymer having the following structure, wherein m and n represent the number of their respective repeating monomers:and a molecular weight ranging from about 1,000 g / mol to about 3,000 g / mol.

35. The tape of claim 34, further comprising a second fluorine-free crosslinking agent comprising a methylhydrosiloxane - phenylmethylsiloxane copolymer having the following structure, wherein m and n represent the number of repeating monomeric units:and a molecular weight of from about 100 g / mol to about 300 g / mol.

36. The tape of claim 30, wherein the composition comprises no more than about 10 wt.% of a vinylmethyl siloxane - dimethylsiloxane copolymer that is dimethylsilyl, dimethylsiloxane or trimethylsiloxane terminated on at least one terminal end, wherein the weight percent is based on the weight of the non-volatile ingredients in the composition.

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