Adhesive article comprising polyamide layer and methods

Abstract

An adhesive article is described comprising a film backing; a thermoplastic layer comprising polyamide disposed on the film backing; and a pressure sensitive adhesive disposed on the thermoplastic layer. The pressure sensitive adhesive may be a rubber-based pressure sensitive adhesive or a silicone-based pressure sensitive adhesive. The thermoplastic layer may further comprise polyolefin and polar moieties. Also described is a methods of making an adhesive article such as by thermal extrusion.

Description

[0001] ADHESIVE ARTICLE COMPRISING POLYAMIDE LAYER AND METHODS

[0002] Summary

[0003] In one embodiment, an adhesive article is described comprising a film backing; a thermoplastic layer comprising polyamide, polyolefin, and polar moieties disposed on the film backing; and a pressure sensitive adhesive disposed on the thermoplastic layer. In some embodiments, the pressure sensitive adhesive is a rubber-based pressure sensitive adhesive or a silicone-based pressure sensitive adhesive.

[0004] In another embodiment, an adhesive article is described comprising a film backing; a thermoplastic layer comprising polyamide disposed on the film backing; and a silicone-based pressure sensitive adhesive disposed on the thermoplastic layer.

[0005] In another embodiment, a method of making an adhesive article comprising: applying a thermoplastic layer to a film backing, wherein the thermoplastic layer comprises polyamide, and optionally a polyolefin comprising polar moieties; and applying a pressure sensitive adhesive to the thermoplastic layer.

[0006] Brief Description of the Drawings

[0007] FIG. 1 is a cross-sectional representation of an adhesive article including a backing and a pressure sensitive adhesive layer disposed thereon.

[0008] Article

[0009] FIG. 1 is a schematic cross-section of an illustrative adhesive article 50 that includes a film backing 120B, a layer 120A comprising polyamide alone or in combination with a polar modified polyolefin disposed on the film backing 120B; and a pressure sensitive adhesive 140 disposed on layer 120A. In some embodiments, the pressure sensitive adhesive is typically selected from rubber-based adhesives and silicone-based adhesives. Layer 120A can improve the adhesion between the fdm backing and pressure sensitive adhesive. When 120B and 120A are coextruded there may not be a discernable interface between these layers, such as depicted in FIG. 1. However, surface 121 comprises the polyamide alone or in combination with a polar modified polyolefin and the opposing surface of the film backing 123 comprises a different organic polymer composition.

[0010] The adhesive article can be a tape, strip, sheet (e.g., perforated sheet), label, roll, web, disc, and kit (e.g., an object for mounting and the adhesive tape used to mount the object).

[0011] In some embodiments, the adhesive article has a haze of greater than 10% according to

[0012] ASTM D1003-07. Film Backing

[0013] The film backing typically comprises an organic polymer. Common organic polymers for film backings include polyolefins, acrylic polymers (PMMA) and copolymer, polyurethanes, and synthetic rubbers including styrenic block copolymers, acrylonitrile-butadiene-styrene copolymers (e.g., styrenebutadiene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene / butylene- styrene block copolymers, styrene-ethylene / propylene-styrene block copolymers). The film backing may comprise a mixture of organic polymers. The film backing may also be a multilayer film comprising two or more of the same or different organic polymers. The term film backing also includes foam.

[0014] The total thickness of the film backing can be at least 5, 10, 15, 20, or 25 microns. In some embodiments, the total thickness of the film backing is no greater than 250, 200, 150, 100, or 50 micrometers.

[0015] In some embodiments, the film backing comprises a polyolefin. Polyolefins included for example polyethylene such as high density polyethylene, low density polyethylene, linear low density polyethylene, and linear ultra low density polyethylene, polypropylene, and polybutylene, poly(alkylene) copolymers, as well as the various molar modified polyolefins as well subsequently be described. One illustrative polyolefin backing film comprises low density poly(ethylene) available from LyondellBassell Industries as PETROTHENE NA 217000.

[0016] Poly(alkylene) copolymer is typically the reaction product of an alkene mixture that includes 1) a first alkene selected from ethene, propene, or a mixture thereof and 2) a second alkene monomer selected from a 1,2-alkene having 4 to 8 carbon atoms. For example, the second alkene monomer often has four, six, or eight carbon atoms. That is, the alkene mixture includes 1) ethene, propene, or a mixture thereof and 2) butene, hexane, octane, or a mixture thereof. These copolymers are typically prepared using a metallocene catalyst. Mixtures or combinations of these copolymers may also be used.

[0017] In some embodiments, the film backing comprises a thermoplastic multilayer material that can be formed, for example, by a coextrusion and blown film process. The process can use an annular die to a form a molten tube of film oriented radially via air pressure in a “bubble” that is pulled lengthwise in the molten area to bring the film to a final desired thickness. Such method is known and described in previously cited US 11097508.

[0018] In some embodiments, the backing layer may have suitable mechanical properties for use in a stretch release adhesive tape. For example, the backing layer may be selected so that it can be stretched (elongated) in a first direction (e.g., a lengthwise direction) at least 50 percent without breaking. In some embodiments, the backing layer 16 can be stretched at least 100, 150, 200, 300, 400 or 500 percent, percent without breaking.

[0019] The Young’s Modulus of the backing layer can be an indicator of the resistance of the backing layer to stretching. The Young's modulus of the backing layer may be no greater than 75,000 psi (about 520 MPa), 50,000 psi (about 345 MPa), 25,000 psi (about 170 MPa), or 10,000 psi (about 70 MPa). The Young’s Modulus is typically at least 10, 20, or 25 MPa. The Young’s Modulus can be measured, for example, using method ASTM D790-07 or ASTM D882-02.

[0020] Laver Comprising Polyamide and Optional Polyolefin

[0021] A layer (e.g. 120) comprising polyamide and optionally polyolefin is disposed on the film backing. In some embodiments, such layer can improve the adhesion between the film backing and pressure sensitive adhesive.

[0022] In some embodiments, such as when the adhesive is a silicone-based adhesive, the polyamide may be present in an amount of 95 or 100 weight percent, based on the total weight of the (e.g. adhesionpromoting) thermoplastic layer.

[0023] In some embodiments, the polyamide is an amorphous polyamide. Amorphous polyamide refers to a polyamide that has an enthalpy of fusion from the second heat ramp of a heat-cool-heat cycle of at least 0 Joules per gram J / g and not greater than 50 or 40 J / g as measured by differential scanning calorimetry (DSC). The enthalpy of fusion of a polyamide is measured by DSC on a differential scanning calorimeter (available under the trade designation Q200 SERIES DSC from TA Instruments, New Castle, DE) using a heat / cool / heat cycle procedure with the following parameters: Equilibrate at (-30.00°C), then ramp heat at 20.00°C / minute to 200.00°C, then ramp cool at 20.00°C / minute to (-30.00°C), then ramp heat at 20.00°C / minute to 200.00°C, with a data collection rate of one data point per second. The enthalpy of fusion is evaluated by a linear integration of the endothermic transition in the range of 35°C-85°C using commercial software (available under the trade designation UNIVERSAL ANALYSIS 2000 software from TA Instruments). In certain embodiments, the amorphous polyamide (typically, a dimer acid-based polyamide) has an enthalpy of fusion from the second heat ramp of a heat-cool-heat cycle of at least 5, 10, 15, 20, 25 or 30 J / g as measured by differential scanning calorimetry (DSC).

[0024] In some embodiments, the amorphous polyamide is at least one amorphous dimer acid-based polyamide. An exemplary amorphous dimer acid-based polyamide is described in U.S. Pat. Pub. No. 2018 / 0305544 (Perez et al.).

[0025] Amorphous polyamides are available, for example, under the trade designations UNI-REZ from Kraton Polymers LLC, Houston, TX, and TECHNOMELT Henkel AG & Co. KGaA, Dusseldorf, Germany. The amorphous polyamide are typically amine-terminated or acid-terminated. Amine- terminated polyamide resin are described in U.S. Pat. No. 3,377,303 (Peerman, et al.). In some embodiments, a combination of amine-terminated and acid terminated polyamide can be utilized.

[0026] The amine-terminated amorphous polyamides have amine numbers, related to the polyamide end groups, in a range of 0.03 to 2.00 (in some embodiments, in a range of 0.05 to 1.00, or even 0.10 to 0.50) milliequivalents per gram (meq / gm). The acid-terminated amorphous polyamides have acid numbers, related to the polyamide end groups, in a range of greater than 0.00 and up to 0.20 (in some embodiments, in a range of 0.01 to 0.10, or even 0.01 to 0.05) meq / gm. Examples of amorphous polyamides include those available, for example, under the trade designations UNI-REZ 2291, UNI- REZ 2635, UNI-REZ 2638, UNI-REZ 2651, and UNI-REZ 2671 from Kraton Polymers LLC, and TECHNOMELT 2279 and TECHNOMELT 6240 from Henkel AG & Co. KGaA.

[0027] In some embodiments, the amorphous polyamide includes an amorphous epoxide chain extended polyamide. Exemplary amorphous epoxide chain extended polyamides can be made as is known in the art. In some embodiments, the amorphous epoxide chain extended polyamide includes up to 2.5 (in some embodiments, up to 2, or even up to 1.5) percent by weight epoxy, based on the total weight of the amorphous epoxide chain extended polyamide. In some embodiments, the amorphous epoxide chain extended polyamide includes at least 0.1 (in some embodiments, at least 0.2, at least 0.25, at least 0.5, at least 0.7, at least 1, or even greater than 1) percent by weight epoxy, based on the total weight of the amorphous epoxide chain extended polyamide. In some embodiments, the amorphous epoxide chain extended polyamide includes 0.1 to 2.5 (in some embodiments, 0.2 to 2.5, 0.25 to 2.5, 0.5 to 2.5, 0.5 to 2, 0.5 to 1.5, 0.7 to 1.5, 1 to 2.5, or greater than 1 and up to 2.5) percent by weight epoxy, based on the total weight of the amorphous epoxide chain extended polyamide.

[0028] In some instances, it is advantageous to react a portion of the amine end groups of the amorphous polyamide with diepoxide resins as described, for example, in U.S. Pat. No. 6,008,313 (Benson et al.). The reaction of the amine end groups and the diepoxide resin can be conducted in the presence or absence of solvent, although processing in the absence of solvent is preferred. The amorphous epoxide chain extended polyamide may provide improved extrusion processing when compared to amorphous polyamides that are not chain extended. The portion of amine end groups that are reacted with the diepoxide resin can be adjusted to provide improved extrusion processing. Exemplary diepoxide resins include the diglycidyl ethers of bisphenol-A, the advanced diglycidyl ethers of bisphenol- A, and the diglycidyl ethers of bisphenol-F. Additional examples of useful diepoxide resins may be found in the “Handbook of Epoxy Resins,” Henry Lee and Kris Neville, McGraw-Hill, 1967. Examples of diepoxide resins include that available, for example, under the trade designations EPON RESIN 828 from Hexion Incorporated, Columbus, OH, and D.E.R. 661 from Olin Corporation, Clayton, MO.

[0029] In some embodiments, such as when the adhesive is a rubber-based adhesive, the (e.g. amorphous) polyamide is blended with one or more polyolefin copolymers. The polyolefin copolymer typically comprises olefins moieties such as ethylene, propylene, or a mixture thereof and polar moieties derived from one or more polar comonomers. In some embodiments, the polyolefin copolymer comprises grafted polar groups.

[0030] The (e.g. amorphous) polyamide is present in an amount of at least 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 weight percent, based on the total weight of the (e.g. adhesion promoting) layer. In some embodiments, the polyamide is present in an amount no greater than 95, 90, 80, 70, 60, 50, 40, 30, 20, or 10 weight percent, based on the total weight of the (e.g. adhesion promoting) layer.

[0031] The polyolefin copolymer is present in an amount of at least 10, 20, 30, 40, 50, 60, 70, 80, 90 weight percent, based on the total weight of the (e.g. adhesion promoting) layer. In some embodiments, the copolymer is present in an amount no greater than 90, 80, 70, 60, 50, 40, 30, 20, or 10 weight percent, based on the total weight of the (e.g. adhesion promoting) layer. In some embodiments, a single polyolefin copolymer is combined with at least one (e.g. amorphous)polyamide polymer. In other embodiments, two or more polyolefin copolymer(s) are combined with at least one (e.g. amorphous)polyamide polymer.

[0032] In some embodiments, the polar (e.g. comonomer) groups are present in an amount of at least 0.1, 0.5 wt.%, or 1 wt.%, based on the total weight of the polar-modified polyolefin. In other embodiments, the polar (e.g. comonomer) groups are present in an amount of at least 2, 3, 4, 5, 6 or 7 wt.%, based on the total weight of the polar-modified polyolefin. In some embodiments, the polar groups are present in an amount no greater than 30, 35, 20, 15 or 10 wt.%, based on the total weight of the polar-modified polyolefin.

[0033] In some embodiments, the polar comonomer is at least one of vinyl acetate, methyl acetate, acrylic acid, methacrylic acid, acid anhydride (e.g. maleic anlydride), alkyl acrylate (e.g. methyl acrylate, ethyl acrylate, butyl acrylate), glycidyl methacrylate, and carbon monoxide. Mixtures of such polar comonomers may be used if desired, thereby forming terpolymers, tetrapolymers, etc., such as ethylene / methyl acrylate / acrylic acid.

[0034] Ethylene / vinyl acetate (EVA) copolymers are commercially available from various suppliers including DuPont Packaging and Industrial Polymers under the trade designations EL VAX 750, EL VAX 550, and EL VAX 350. Ethylene / acrylic acid (EAA) copolymers are available from various suppliers such as Dow under the trade designation PRIMACOR 1410 or PRIMACOR 3460 as well as Honeywell Performance Materials and Technologies under the trade designation A-C 540, A-C 580 and A-C 5120. Ethylene / methacrylic acid copolymers are available from various suppliers such as DuPont Packaging and Industrial Polymers under the trade designations NUCREL 925 and NUCREL 30707. Other ethylene-containing copolymers including two or more polar monomers are commercially available from various suppliers including DuPont Packaging and Industrial Polymers under the trade designations BYNEL E418, BYNEL3101, and ELVALOY 741.

[0035] In some embodiments, the polar-modified polyolefin may comprise grafted polar groups such as maleic anhydride groups, thereby forming maleic anhydride grafted polyolefins (e.g., maleic anhydride grafted ethylene and / or maleic anhydride grafted propylene). One illustrative polar-modified polyolefin that comprise grafted polar groups is available from Dow Inc., Midland, MI as Bynel 40E529.

[0036] In some embodiments, the polyolefin comprises (meth)acrylic acid moieties in an amount of at least 2, 3, 4, 5, 6 or 7 wt.%, based on the total weight of the polar-modified polyolefin. In some embodiments, the polyolefin comprises (meth)acrylic acid moieties in an amount no greater than 20, 15, or 10 wt.%.

[0037] In some embodiments, the polyolefin comprises alkyl (e.g. methyl) acrylate moieties in an amount of at least 10, 15, or 20 wt.%, based on the total weight of the polar-modified polyolefin.

[0038] The preferred composition can depend on the adhesive. In some embodiments, an amine- terminated polyamide is combined with a polyolefin comprising less than 9, 8, or 7 wt.% acrylic acid moieties and optionally vinyl acetate moieties. In another embodiments, an amine-terminated polyamide is combined with a polyolefin having a methyl acrylate concentration of at least 15 or 20 wt.%.

[0039] The adhesion-promoting layer may optionally comprise other (e.g. thermoplastic) polymers that are not (e.g. amorphous) polyamides or polyolefins.

[0040] In one embodiment, the other (e.g. thermoplastic) polymer is a styrenic block copolymer. Representative block copolymers are also useful for the backing film, as previously described.

[0041] The other (e.g. thermoplastic) block copolymer is optionally present in an amount of at least 1, 2, 3, 4, or 5 weight percent, based on the total weight of the (e.g. adhesion promoting) layer. In some embodiments, the other (e.g. thermoplastic) block copolymer is present in an amount no greater than 25, 20, 15, 10, or 5 weight percent, based on the total weight of the (e.g. adhesion promoting) layer.

[0042] In some embodiments, at least one layer of the (e.g. coextmded) polymeric film backing may comprise various additives as known in the art including for example ultraviolet (UV) absorbers, hindered amine light stabilizers (HALS), antioxidants, antistatic agents, colorants such as pigments and dyes including metallic particles, and fillers. The outermost layer of the e.g. coextruded) polymeric film backing (i.e. the opposite major surface as the adhesion promoting layer) may optionally comprise a slip additive or an antiblocking agent.

[0043] Method of Making

[0044] In some embodiments, the backing layers can be coextruded using techniques known in the art, including those described in “Polymer Engineering Principles,” Progelhof, R.C., and Throne, J.L., Hanser / Gardner Publications, Inc., Cincinnati, OH, 1993.

[0045] In some embodiments, the backing layer and adhesion promoting layer can be formed, for example, by a thermal coextrusion and blown film process. The process can use an annular die (such as described in US11097508; incorporated herein by reference) to a form a molten tube of film oriented radially via air pressure in a “bubble” that is pulled lengthwise in the molten area to bring the film to a final desired thickness.

[0046] The coextrusion can be run at any suitable temperature. In some embodiments, the extrusion can be run at a temperature ranging from 160C to 220°C (in some embodiments, 180°C to 210°C, 185°C to 200°C, or even 190°C to 210°C). The extrusion rate of an individual layer can vary spending on the size of the extruder and the desired thickness of the layer. In some embodiments, the extrusion rate was in the range of 30 to 100 revolutions per minutes.

[0047] In some embodiments, the thermoplastic multilayer film may comprise at least 2, 3, 4, 5, 6 or 7 layers. The layers may comprise the same of different thermoplastic polymer (e.g. polyolefin) materials.

[0048] The thermoplastic multilayer film has two major surfaces and a thickness in the direction orthogonal to the major surfaces. An adhesive is disposed on one of the major surface comprising polyamide or polyamide blended with polar-modified polyolefin (e.g. layer 7 of the subsequent examples. The opposing surface of thermoplastic film may comprise one or more thermoplastic (e.g. polyolefin) layers that form the film backing of the adhesive article. In some embodiments, one more tie layers may be present between the film backing layer(s) and the major surface comprising polyamide or polyamide blended with polar-modified polyolefin. In some embodiments, the tie layer(s) (e.g. layer 6 of the subsequent examples comprises a polar-modified polyolefin. In some embodiments, the tie layer comprises the same or higher polar (e.g. acidic) polymerized monomer content as the polar-modified polyolefin blended with the polyamide.

[0049] Alternatively, the (e.g. adhesion promoting) thermoplastic layer comprising the polyamide or polyamide and polar modified polyolefin, can be applied to a (e.g. preformed) film backing by any suitable technique including solvent less methods such as thermal extrusion or as an organic solventbased coating.

[0050] Adhesive

[0051] The article further comprises a pressure sensitive adhesive disposed on the (e.g. adhesionpromoting) layer. The pressure sensitive adhesive may be (temporarily) covered by a release liner (until use).

[0052] The thermoplastic layer comprising polyamide or polyamide, polyolefin, and polar moieties disposed on the film backing can improve adhesion to a variety of pressure sensitive adhesives. Suitable (e.g. pressure sensitive) adhesives include natural or synthetic rubber-based pressure sensitive adhesives, acrylic pressure sensitive adhesives, vinyl alkyl ether pressure sensitive adhesives, silicone pressure sensitive adhesives, polyester pressure sensitive adhesives, polyamide pressure sensitive adhesives, poly-alpha-olefins, polyurethane pressure sensitive adhesives, and styrenic block copolymer based pressure sensitive adhesives.

[0053] Suitable pressure sensitive adhesives may be made via a wide variety of techniques. They may include an emulsion pressure sensitive adhesive, a solvent-borne pressure sensitive adhesive, a photo- polymerizable pressure sensitive adhesive, a hot melt pressure sensitive adhesive (i.e., hot melt extruded pressure sensitive adhesive), or a combination thereof. The adhesive may comprise a single layer or multiple layers of the same or different adhesive compositions.

[0054] Coatable hot melt adhesive can then be delivered out of a film die, subsequently contacting the drawn adhesive to a moving plastic web or other suitable substrate. A related coating method involves extruding the coatable hot melt adhesive and a coextruded backing material from a film die and cooling the layered product to form an adhesive tape. Other forming methods involve directly contacting the coatable hot melt adhesive to a rapidly moving plastic web or other suitable preformed substrate. Using this method, the adhesive blend is applied to the moving preformed web using a die having flexible die lips, such as a rotary rod die. After forming by any of these continuous methods, the adhesive films or layers can be solidified by quenching using both direct methods (e.g., chill rolls or water baths) and indirect methods (e.g., air or gas impingement). In typical embodiments, the adhesive is a pressure sensitive adhesive generally have a storage modulus (E’) as can be measured by Dynamic Mechanical Analysis at room temperature (25°C) of less than 3 x 106dynes / cm at a frequency of 1 Hz.

[0055] The pressure sensitive adhesive may further include one or more suitable additives such as crosslinking agents (e.g. multifunctional (meth)acrylate crosslinkers (e.g. TMPTA), epoxy crosslinking agents, isocyanate crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, etc.), tackifiers (e.g., phenol modified terpenes and rosin esters such as glycerol esters of rosin and pentaerythritol esters of rosin, as well as C5 and C9 hydrocarbon tackifiers), thickeners, plasticizers, fillers, antioxidants, ultraviolet absorbers, antistatic agents, surfactants, leveling agents, colorants, flame retardants, and silane coupling agents.

[0056] In some embodiments, the pressure sensitive adhesive is a (e.g. tackified) rubber-based adhesive such as natural rubber, olefins, silicones, polyisoprene, polybutadiene, polyurethanes, styrene- isoprene-styrene and styrene-butadiene-styrene block copolymers, and other elastomers. Various pressure sensitive adhesive are known such as described in the Handbook of Pressure Sensitive Adhesive Technology, D. Satas (ed.), (1989), Van Nostrand Reinhold, New York..

[0057] One illustrative (e.g. tackified) rubber-based adhesive used to evaluate the improvement in adhesion in the forthcoming examples is Rubber Tape 1, having a 25 micron thick layer of hot melt adhesive comprising a mixture of 100 parts of SIS block copolymer (having a styrene content of 14.3%, a coupling efficiency of 88% and a melt index of 9 g / 10 min (condition G)), 85 parts of tackifying resin (C9 modified C5 having a softening point of 87°C) and 2 parts of antioxidant disposed on a 50 micron thick of corona treated biaxially oriented polypropylene (BOPP) film.

[0058] In other embodiments, the adhesive is a silicone adhesive.

[0059] Silicone adhesive generally comprise a silicone material according to the following formula illustrating a siloxane backbone with aliphatic and / or aromatic substituents:

[0060] R5 Rl R3 R5

[0061] R5— Si-O~ |~ Si-O~ |~ Si-O~ |~ Si- 5 | L | Jml | Jn |

[0062] R5 R2 R4 R5 wherein Rl, R2, R3, and R4 are independently selected from the group consisting of an alkyl group and an aryl group, each R5 is an alkyl group and n and m are integers, and at least one of m or n is not zero. In some embodiments, one or more of the alkyl or aryl groups may contain a halogen substituent, e.g., fluorine. For example, in some embodiments, one or more of the alkyl groups may be -CH2CH2C4F9.

[0063] In some embodiments, R5 is a methyl group, i.e., the nonfunctionalized poly diorgano siloxane material is terminated by trimethylsiloxy groups. In some embodiments, Rl and R2 are alkyl groups and n is zero, i.e., the material is a poly(dialkylsiloxane). In some embodiments, the alkyl group is a methyl group, i.e., poly(dimethylsiloxane) (“PDMS”). In some embodiments, Rl is an alkyl group, R2 is an aryl group, and n is zero, i.e., the material is a poly(alkylarylsiloxane). In some embodiments, R1 is methyl group and R2 is a phenyl group, i.e., the material is poly(methylphenylsiloxane). In some embodiments, R1 and R2 are alkyl groups and R3 and R4 are aryl groups, i.e., the material is a poly (dialkyldiarylsiloxane). In some embodiments, R1 and R2 are methyl groups, and R3 and R4 are phenyl groups, i.e., the material is poly(dimethyldiphenylsiloxane).

[0064] In some embodiments, the nonfunctionalized polydiorganosiloxane materials may be branched. For example, one or more of the Rl, R2, R3, and / or R4 groups may be a linear or branched siloxane with alkyl or aryl (including halogenated alkyl or aryl) substituents and terminal R5 groups.

[0065] As used herein, “nonfunctional groups” are either alkyl or aryl groups consisting of carbon, hydrogen, and in some embodiments, halogen (e.g., fluorine) atoms. As used herein, a “nonfunctionalized polydiorganosiloxane material” is one in which the Rl, R2, R3, R4, and R5 groups are nonfunctional groups.

[0066] Generally, functional silicone systems include specific reactive groups attached to the poly siloxane backbone of the starting material (for example, hydrogen, hydroxyl, vinyl, allyl, or acrylic groups). As used herein, a “functionalized polydiorganosiloxane material” is one in which at least one of the R-groups of Formula 2 is a functional group.

[0067] <2)

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

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

[0070] Other silicone materials comprise siloxane moieties in addition to other moieties in the backbone, such as urea, amide, oxamide, and urethane.

[0071] Suitable siloxane polyurea block copolymers may have the formula: wherein each R is a moiety that, independently, is an alkyl moiety, having about 1 to 12 carbon atoms, and may be substituted with, for example, trifluoroalkyl or vinyl groups, a vinyl radical or a higher alkenyl radical, a cycloalkyl moiety having from about 6 to 12 carbon atoms and may be substituted with alkyl, fluoroalkyl, and vinyl groups, or an aryl moiety having from about 6 to 20 carbon atoms and may be substituted with, for example, alkyl, cycloalkyl, fluoroalkyl and vinyl groups or R is a perfluoroalkyl group as described in US Patent No. 5,028,679, or a fluorine- containing group, as described in US Patent No. 5,236,997, or a perfluoroether-containing group, as described in US Patent Nos. 4,900,474 and 5,118,775; typically, at least 50% of the R moieties are methyl radicals with the balance being monovalent alkyl or substituted alkyl radicals having from 1 to 12 carbon atoms, alkenyl radicals, phenyl radicals, or substituted phenyl radicals; each Z is a polyvalent radical that is an arylene radical or an aralkylene radical having from about 6 to 20 carbon atoms, an alkylene or cycloalkylene radical having from about 6 to 20 carbon atoms, in some embodiments Z is 2,6-tolylene, 4,4’-methylenediphenylene, 3,3’-dimethoxy-4,4’- biphenylene, tetramethyl-m-xylylene, 4,4 ’-methylenedicyclo hexylene, 3,5,5-trimethyl-3- methylenecyclohexylcne, 1,6-hexamethylene, 1,4-cyclo hexylene, 2,2,4-trimethylhexylene and mixtures thereof; each Y is a polyvalent radical that independently is an alkylene radical of 1 to 10 carbon atoms, an aralkylene radical or an arylene radical having 6 to 20 carbon atoms; each D is selected from the group consisting of hydrogen, an alkyl radical of 1 to 10 carbon atoms, phenyl, and a radical that completes a ring structure including B or Y to form a heterocycle; where B is a polyvalent radical selected from the group consisting of alkylene, aralkylene, cycloalkylene, phenylene, heteroalkylene, including for example, polyethylene oxide, polypropylene oxide, polytetramethylene oxide, and copolymers and mixtures thereof; m is a number that is 0 to about 1000; n is a number that is at least 1; and p is a number that is at least 10, in some embodiments 15 to about 2000, or even 30 to 1500. Useful siloxane polyurea block copolymers are disclosed in, e.g., US Patent Nos. 5,512,650, 5,214,119, 5,461,134, and 7,153,924 and PCT Publication Nos. WO 96 / 35458, WO 98 / 17726, WO 96 / 34028, WO 96 / 34030 and WO 97 / 40103.

[0072] Another useful class of elastomeric siloxane polymers that can be prepared from amine- functional polysiloxanes are oxamide-based polymers such as polydiorganosiloxane polyoxamide block copolymers. Examples of polydiorganosiloxane polyoxamide block copolymers are presented, for example, in US Patent Publication No. 2007 / 0148475. The polydiorganosiloxane polyoxamide block copolymer contains at least two repeat units of the following formula:

[0073] In this formula, each R1is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo, wherein at least 50 percent of the R1groups are methyl. Each Y is independently an alkylene, aralkylene, or a combination thereof. Subscript n is independently an integer of 40 to 1500 and the subscript p is an integer of 1 to 10. Group G is a divalent group that is the residue unit that is equal to a diamine of formula R3HN-G-NHR3minus the two -NHR3groups. Group R3is hydrogen or alkyl (e.g., an alkyl having 1 to 10, 1 to 6, or 1 to 4 carbon atoms) or R3taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group (e.g., R3HN-G- NHR3is piperazine or the like). Each asterisk (*) indicates a site of attachment of the repeat unit to another group in the copolymer such as, for example, another repeat unit of Formula 3.

[0074] Suitable alkyl groups for R1in Formula 3 typically have 1 to 10, 1 to 6, or 1 to 4 carbon atoms. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, isopropyl, n-propyl, n-butyl, and iso-butyl. Suitable haloalkyl groups for R1often have only a portion of the hydrogen atoms of the corresponding alkyl group replaced with a halogen. Exemplary haloalkyl groups include chloroalkyl and fluoroalkyl groups with 1 to 3 halo atoms and 3 to 10 carbon atoms. Suitable alkenyl groups for R1often have 2 to 10 carbon atoms. Exemplary alkenyl groups often have 2 to 8, 2 to 6, or 2 to 4 carbon atoms such as ethenyl, n-propenyl, and n-butenyl. Suitable aryl groups for R1often have 6 to 12 carbon atoms. Phenyl is an exemplary aryl group. The aryl group can be unsubstituted or substituted with an alkyl (e.g., an alkyl having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), an alkoxy (e.g., an alkoxy having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), or halo (e.g., chloro, bromo, or fluoro). Suitable aralkyl groups for R1usually have an alkylene group having 1 to 10 carbon atoms and an aryl group having 6 to 12 carbon atoms. In some exemplary aralkyl groups, the aryl group is phenyl and the alkylene group has 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms (i.e., the structure of the aralkyl is alkylene-phenyl where an alkylene is bonded to a phenyl group).

[0075] At least 50 percent of the R1groups are methyl. For example, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 95 percent, at least 98 percent, or at least 99 percent of the R1groups can be methyl. The remaining R1groups can be selected from an alkyl having at least two carbon atoms, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo.

[0076] Each Y in Formula 3 is independently an alkylene, aralkylene, or a combination thereof. Suitable alkylene groups typically have up to 10 carbon atoms, up to 8 carbon atoms, up to 6 carbon atoms, or up to 4 carbon atoms. Exemplary alkylene groups include methylene, ethylene, propylene, butylene, and the like. Suitable aralkylene groups usually have an arylene group having 6 to 12 carbon atoms bonded to an alkylene group having 1 to 10 carbon atoms. In some exemplary aralkylene groups, the arylene portion is phenylene. That is, the divalent aralkylene group is phenylene-alkylene where the phenylene is bonded to an alkylene having 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. As used herein with reference to group Y, “a combination thereof’ refers to a combination of two or more groups selected from an alkylene and aralkylene group. A combination can be, for example, a single aralkylene bonded to a single alkylene (e.g., alkylene-arylene-alkylene). In one exemplary alkylene-arylene-alkylene combination, the arylene is phenylene and each alkylene has 1 to 10, 1 to 6, or 1 to 4 carbon atoms.

[0077] Each subscript n in Formula 3 is independently an integer of 40 to 1500. For example, subscript n can be an integer up to 1000, up to 500, up to 400, up to 300, up to 200, up to 100, up to 80, or up to 60. The value of n is often at least 40, at least 45, at least 50, or at least 55. For example, subscript n can be in the range of 40 to 1000, 40 to 500, 50 to 500, 50 to 400, 50 to 300, 50 to 200, 50 to 100, 50 to 80, or 50 to 60.

[0078] The subscript p is an integer of 1 to 10. For example, the value of p is often an integer up to 9, up to 8, up to 7, up to 6, up to 5, up to 4, up to 3, or up to 2. The value of p can be in the range of 1 to 8, 1 to 6, or 1 to 4.

[0079] Group G in Formula 3 is a residual unit that is equal to a diamine compound of formula R3HN- G-NHR3minus the two amino groups (i.e., -NHR3groups). Group R3is hydrogen or alkyl (e.g., an alkyl having 1 to 10, 1 to 6, or 1 to 4 carbon atoms) or R3taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group (e.g., R3HN-G-NHR3is piperazine). The diamine can have primary or secondary amino groups. In most embodiments, R3is hydrogen or an alkyl. In many embodiments, both of the amino groups of the diamine are primary amino groups (i.e., both R3groups are hydrogen) and the diamine is of formula H2N-G-NH2.

[0080] In some embodiments, G is an alkylene, heteroalkylene, polydiorganosiloxane, arylene, aralkylene, or a combination thereof. Suitable alkylenes often have 2 to 10, 2 to 6, or 2 to 4 carbon atoms. Exemplary alkylene groups include ethylene, propylene, butylene, and the like. Suitable heteroalkylenes are often polyoxyalkylenes such as polyoxyethylene having at least 2 ethylene units, polyoxypropylene having at least 2 propylene units, or copolymers thereof. Suitable polydiorganosiloxanes include the polydiorganosiloxane diamines of Formula 1, which are described above, minus the two amino groups. Exemplary polydiorganosiloxanes include, but are not limited to, polydimethylsiloxanes with alkylene Y groups. Suitable aralkylene groups usually contain an arylene group having 6 to 12 carbon atoms bonded to an alkylene group having 1 to 10 carbon atoms. Some exemplary aralkylene groups are phenylenealkylene where the phenylene is bonded to an alkylene having 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. As used herein with reference to group G, “a combination thereof’ refers to a combination of two or more groups selected from an alkylene, heteroalkylene, polydiorganosiloxane, arylene, and aralkylene. A combination can be, for example, an aralkylene bonded to an alkylene (e.g., alkylene-arylene-alkylene). In one exemplary alkylene-arylene-alkylene combination, the arylene is phenylene and each alkylene has 1 to 10, 1 to 6, or 1 to 4 carbon atoms.

[0081] The polydiorganosiloxane polyoxamide tends to be free of groups having a formula -Ra-(CO)-NH- where Rais an alkylene. All of the carbonylamino groups along the backbone of the copolymeric material are part of an oxalylamino group (i.e., the -(CO)-(CO)-NH- group). That is, any carbonyl group along the backbone of the copolymeric material is bonded to another carbonyl group and is part of an oxalyl group. More specifically, the polydiorganosiloxane polyoxamide has a plurality of aminoxalylamino groups.

[0082] Another useful class of elastomeric siloxane polymers is amide-based polysiloxane polymers. Such polymers are similar to the urea-based polymers, containing amide linkages (-N(D)-C(O)-) instead of urea linkages (-N(D)-C(O)-N(D)-), where C(O) represents a carbonyl group and D is a hydrogen or alkyl group.

[0083] Another example of a useful class of elastomeric siloxane polymers is urethane-based siloxane polymers such as siloxane polyurea-urethane block copolymers. Siloxane polyurea-urethane block copolymers include the reaction product of a polydiorganosiloxane diamine (also referred to as siloxane diamine), a diisocyanate, and an organic polyol. Such materials are structurally very similar to the structure of Formula I except that the -N(D)-B-N(D)- links are replaced by -O-B-O- links. Examples are such polymers are presented, for example, in US Patent No. 5,214,119.

[0084] The silicone materials comprising a siloxane backbone optionally in combination with other moieties may be oils, fluids, gums, elastomers, or resins, e.g., friable solid resins. Lower molecular weight, lower viscosity materials are referred to as fluids or oils, while higher molecular weight, higher viscosity materials are referred to as gums; however, there is no sharp distinction between these terms. Silicone oils are commercially available (e.g. from Wacker) at viscosities from 0.65 to 1,000,000 mPa*scc at 25 °C. In typical embodiments, higher viscosity (e.g. non-functional) liquid polydiorganosiloxanes are preferred. In some embodiments, the liquid polydiorganosiloxane has a viscosity of at least 50,000; 100,000; 250,000; 500,000; 750,000; or 1,000,000 mPa’sec at 25 °C. When polydiorganosiloxane gum is utilized, the viscosity may be greater than 1,000,000 mPa*scc at 25 °C.

[0085] In some embodiments, the silicone adhesive further comprise a silicate tackifying resin. Suitable silicate tackifying resins include those resins composed of the following structural units M (i.e., monovalent R^SiO^^ units), D (i.e., divalent R'2SiO2 / 2 units), T (i.e., trivalent R'SiC>3 / 2 units), and Q (i.e., quaternary SiOq / 2 units), and combinations thereof. Typical exemplary silicate resins include MQ silicate tackifying resins, MQD silicate tackifying resins, and MQT silicate tackifying resins. These silicate tackifying resins usually have a number average molecular weight in the range of 100 to 50,000- gm / mole, e.g., 500 to 15,000 gm / mole and generally R' groups are methyl groups.

[0086] MQ silicate tackifying resins are copolymeric resins where each M unit is bonded to a Q unit, and each Q unit is bonded to at least one other Q unit. Some of the Q units are bonded to only other Q units. However, some Q units are bonded to hydroxyl radicals resulting in HOSiC>3 / 2 units (i.e., "TOH" units), thereby accounting for some silicon-bonded hydroxyl content of the silicate tackifying resin. The amount of silicon bonded hydroxyl groups (i.e., silanol) on the MQ resin may be reduced to no greater than 1.5 weight percent, no greater than 1.2 weight percent, no greater than 1.0 weight percent, or no greater than 0.8 weight percent based on the weight of the silicate tackifying resin. This may be accomplished, for example, by reacting hexamethyldisilazane with the silicate tackifying resin. Such a reaction may be catalyzed, for example, with trifluoroacetic acid. Alternatively, trimethylchlorosilane or trimethylsilylacetamide may be reacted with the silicate tackifying resin, a catalyst not being necessary in this case.

[0087] MQD silicone tackifying resins are terpolymers having M, Q and D units. In some embodiments, some of the methyl R' groups of the D units can be replaced with vinyl (CH2=CH-) groups ("D^1" units). MQT silicate tackifying resins are terpolymers having M, Q and T units.

[0088] Suitable silicate tackifying resins are commercially available from sources such as Dow Coming (e.g., DC 2-7066), Momentive Performance Materials (e.g., SR545 and SR1000), and Wacker Chemie AG (e.g., BELSIL TMS-803).

[0089] In some embodiments, the layer of polydiorganosiloxane composition comprises (e.g. silicate) tackifying resin in an amount of at least 5, 10, 15, 20, 25, 30 wt.% or greater of the total silicone adhesive composition.

[0090] One illustrative silicone adhesive used to evaluate the improvement in adhesion in the forthcoming examples is Silicone Tape 1, comprising 80 wt. % of a linear non-reactive PDMS with a viscosity of approximately 1,000,000 cSt available from Wacker (Adrian, MI) under the trade designation AK 1000000 SILICONE FLUID and 20 wt. % of an MQ silicate resin available from Wacker (Adrian, MI) under the trade designation MQ-RESIN POWDER 803 TF. The adhesive was fed into a twin screw extruder at a temperature of approximately 204°C (400°F) and hot-melt coated at a thickness of 100 micrometers (4 mil) using a die coating at 93°C (200°F) onto a backing film. The backing film was provided by extruding a thermoplastic polyester elastomer onto a nonwoven polyester material, wherein the elastomer material had a three second Shore D hardness of 32 as tested per ISO 868 and a melting temperature of approximately 212 °C. The backing had a total thickness of 0.0047 inches (119 micrometers). The adhesive was then crosslinked with e-beam irradiation in an inerted chamber (< 50 ppm oxygen) at a dosage of 2.0 Mrad at an accelerating voltage of 280-300 keV.

[0091] As demonstrated by the forthcoming examples, the peel adhesion between the pressure sensitive adhesive and adhesion-promoting thermoplastic layer described herein is greater than the peel adhesion between the pressure sensitive adhesive and the film backing. The presence of the (e.g. adhesion promoting) thermoplastic layer described herein can increase improve adhesion by at least 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5 N / cm force. Materials

[0092] Preparation of Examples El - E31.

[0093] Seven-layer film examples, E1-E31, were produced on seven layer pancake stack die (Type LF-400 Coex 7-layer from Labtech Engineering Engineering Co. Ltd., Thailand). Airflow to the die was manually controlled to achieve a blow up ratio of approximately 2:1. The bubble was subsequently collapsed approximately ten feet above die and rolled up. The feed materials were supplied by 7 independent 20 mm diameter single screw extruders with an approximately 30: 1 L / D. The layer composition of examples El - E31 is shown in Table 1.

[0094] The temperature settings of the extmders 1 - 5, in Celsius, for Examples El - E21 were held between 160°C - 182°C with zones 1 held at 160°C and zones 2 and 3 held at 182°C. The temperature settings of the extruder 6, in Celsius, for Examples El - E21 were held between 138°C - 160°C with zone 1 held at 138°C and zones 2 and 3 held at 160°C. The temperature settings of the extruder 7, in Celsius, for Examples El - E21 were held between 138°C - 182°C with zone 1 held at 138°C and zones 2 and 3 held between 149 - 182°C. The screw speed for extruders 1 - 5 were held at 30 RPM for all examples. The screw speed for extruder 6 was held at 20 RPM for all examples. The screw speed for extmder 7 was held between 20 - 40 RPM for all examples. The adapter and die temperatures were held constant at 171 °C for all examples. Layers 1 - 5 had a calculated thickness of approximately 10 micrometers and layers 6 - 7 had a calculated thickness of approximately 8 micrometers based on volumetric flow considerations through the extruder. All extruders feeding the die had a compression ratio of 3 : 1 and a Maddock mixing section.

[0095] The temperature settings of the extmders 1 - 6, in Celsius, for Examples E22 - E31 were held between 160°C - 171°C with zones 1 held at 160°C and zones 2 and 3 held at 171°C. The temperature settings of the extruder 7, in Celsius, for Examples E22 - E31 were held between 138°C - 160°C with zone 1 held at 138°C and zones 2 and 3 held between 160°C. The screw speed for extruders 1 - 5 were held at 30 RPM for all examples. The screw speed for extruder 6 and 7 was held at 23 RPM for all examples. The adapter and die temperatures were held constant at 171°C for all examples. Layers 1 - 5 had a calculated thickness of approximately 10 micrometers and layers 6 - 7 had a calculated thickness of approximately 8 micrometers based on volumetric flow considerations through the extruder. All extruders feeding the die had a compression ratio of 3 : 1 and a Maddock mixing section.

[0096] Table 1. Multilayer Films of Examples El - E31.

[0097] Layers 1-5 were Petrothene NA 217000. Layer 6 was Nucrel 30707 for Examples El - E21 and was Nucrel 31001 for Examples E22 - E31. The composition of Layer 7 is described below:

[0098]

[0099] Preparation of Peel Adhesion Samples

[0100] Films El - E21 were each laminated with pressure sensitive adhesive (PSA) tapes available from 3M, Saint Paul, MN. Two tapes were used for this purpose: 3M 2525 Tape which is a natural mbber based PSA tape and 3M 8402 Tape which is a silicone based PSA tape. In each case, the PSA tape was applied by hand to examples El - E21 in 3 replicates while avoiding creases and bubbles in the lamination. The films were then pressure laminated by running a 1.0 kg roller over the laminates twice. The films were then aged for 24 hours in a 22°C, 50% relative humidity environment for 24 hours. The control sample for the study was the backside of Film E4, that consists of Layer 1, i.e. Petrothene NA 21700 unprimed.

[0101] Films E22 - E31 were each laminated with Silicone Tape 1 and Rubber Tape 1. In each case, the PSA tape was applied by hand to examples E22 - E31 in 3 replicates while avoiding creases and bubbles in the lamination. The films were then pressure laminated by running a 1.0 kg roller over the laminates twice. The films were then aged for 24 hours in a 22°C, 50% relative humidity environment for 24 hours. The control sample for the study was the backside of Film E24, that consists of Layer 1, i.e. Petrothene NA 21700 unprimed.

[0102] 90° Degree Peel Adhesion Testing.

[0103] Peel adhesion testing was performed at room temperature and 90° using an SP-2000 IMass Peel Tester (Accord, MA). The test conditions for the peel adhesion test were as follows: peel rate: 90 inches / minute (3.81 cm / second), peel equilibration time: 0.5 seconds, peel averaging time: 5 seconds Each film sample, El - E31, was tested against each PSA tape in 3 replicates. For each result, the average peel force across the entire 90° peel is reported in N / cm in Tables 2 - 4. Notably 1 N / cm + 259 grams / inch(2.54 cm). Table 2. 90° Peel Adhesion Results in N / cm for Films El - E9

[0104] Table 3. 90° Peel Adhesion Results in N / cm for Films E10 - E21 against silicone, rubber

[0105] Table 4. 90° Peel Adhesion Results in N / cm for Films E22 - E31

Claims

What is claim is:

1. An adhesive article comprising: a film backing; a thermoplastic layer comprising polyamide, polyolefin, and polar moieties disposed on the film backing; and a pressure sensitive adhesive disposed on the thermoplastic layer.

2. The adhesive article of claim 1 wherein the film backing comprise polyolefin.

3. The adhesive article of claim 2 wherein the polyolefin is selected from polyethylene, polypropylene, and combinations thereof.

4. The adhesive article of claims 1-3 wherein the polyamide is an amorphous polyamide.

5. The adhesive article of claims 1-4 wherein the polar moieties are derived from a polar monomer selected from the group consisting of vinyl acetate, methyl acetate, acrylic acid, methacrylic acid, acid anhydride, C1-C4 alkyl acrylate, glycidyl methacrylate, and carbon monoxide.

6. The adhesive article of claims 1-5 wherein the thermoplastic layer comprises other thermoplastic polymers, including styrenic block copolymers, in an amount up to 25 wt.%.

7. The adhesive article of claims 1-6 wherein the film backing is an organic polymer that is not a polyolefin.

8. The adhesive article of claims 1-7 wherein the pressure sensitive adhesive is a rubber-based pressure sensitive adhesive.

9. The adhesive article of claims 1-7 wherein the pressure sensitive adhesive is a silicone-based pressure sensitive adhesive.

10. The adhesive article of claims 1-7 wherein the peel adhesion between the pressure sensitive adhesive and thermoplastic layer is greater than the peel adhesion between the pressure sensitive adhesive and the film backing.

11. An adhesive article comprising: a film backing; a thermoplastic layer comprising polyamide disposed on the film backing; and a silicone-based pressure sensitive adhesive disposed on the thermoplastic layer.

12. The adhesive article of claim 11 further characterized by claims 2-7 and 10.

13. A method of making an adhesive article comprising: applying a thermoplastic layer to a film backing, wherein the thermoplastic layer comprises polyamide, and optionally a polyolefin comprising polar moieties; and applying a pressure sensitive adhesive to the thermoplastic layer.

14. The method of claim 13 wherein the thermoplastic layer and film backing are prepared by thermal coextrusion.

15. The method of claims 13-14 wherein the pressure sensitive adhesive is a silicone-based pressure sensitive adhesive.

16. The method of claims 13-15 wherein the thermoplastic layer comprises the polyolefin comprising polar moieties.

17. The method of claim 15 wherein the pressure sensitive adhesive is a rubber-based pressure sensitive adhesive.

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