WO2015157019A1 - Articles revêtus d'adhésif autocollant appropriés pour le collage à des surfaces rugueuses - Google Patents

Articles revêtus d'adhésif autocollant appropriés pour le collage à des surfaces rugueuses Download PDF

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Publication number
WO2015157019A1
WO2015157019A1 PCT/US2015/023330 US2015023330W WO2015157019A1 WO 2015157019 A1 WO2015157019 A1 WO 2015157019A1 US 2015023330 W US2015023330 W US 2015023330W WO 2015157019 A1 WO2015157019 A1 WO 2015157019A1
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Prior art keywords
adhesive
article
pressure sensitive
adhesive layer
meth
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PCT/US2015/023330
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English (en)
Inventor
Arlin L. WEIKEL
Corinne E. LIPSCOMB
Jonathan E. JANOSKI
John W. Vanderzanden
Kevin M. Lewandowski
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3M Innovative Properties Company
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Publication of WO2015157019A1 publication Critical patent/WO2015157019A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/22—Expanded, porous or hollow particles
    • C08K7/24—Expanded, porous or hollow particles inorganic
    • C08K7/28—Glass
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
    • C09J2301/124—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
    • C09J2301/1242—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape the opposite adhesive layers being different
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/20—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive itself
    • C09J2301/208—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive itself the adhesive layer being constituted by at least two or more adjacent or superposed adhesive layers, e.g. multilayer adhesive
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
    • C09J2301/408—Additional features of adhesives in the form of films or foils characterized by the presence of essential components additives as essential feature of the adhesive layer
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
    • C09J2301/412—Additional features of adhesives in the form of films or foils characterized by the presence of essential components presence of microspheres

Definitions

  • FIGs. 1-5 depict various cross-sectional views of embodiments of multilayer adhesive coated articles.
  • FIGs. 6-8 depict the tan delta, the ratio of the shear loss modulus (G") to the shear storage modulus (G'), as determined by dynamic mechanical analysis. Summary
  • an adhesive coated article comprising a substrate comprising a first major surface and a second opposing major surface and a pressure sensitive adhesive layer disposed on the first major surface of the substrate.
  • the pressure sensitive adhesive layer is cleanly removable from paper, reusable, and has a shear to orange peel dry wall with a 250 g weight of at least 500 minutes.
  • the pressure sensitive adhesive layer is preferably a multilayer adhesive.
  • an adhesive coated article comprising a substrate comprising a first major surface and a second opposing major surface and a multilayer pressure sensitive adhesive layer disposed on the first major surface of the substrate.
  • the multilayer pressure sensitive adhesive comprises a first adhesive layer disposed on the first major surface of the substrate, and a second pressure sensitive adhesive skin layer disposed upon the first layer.
  • At least the second skin layer is an acrylic multilayer adhesive comprising no greater than 1 wt-% of polymerized units derived from acid functional monomers.
  • the first adhesive layer is conformable.
  • the first and second adhesive layers are acrylic adhesives comprising no greater than 1 wt-% of polymerized units derived from acid functional monomers.
  • the first adhesive layer is crosslinked with a crosslinking monomer comprising at least one C3 to C20 olefin group.
  • the substrate is a release liner, a backing, or an (e.g. mounting) article such as a hook.
  • a removable release liner is typically disposed upon the second pressure sensitive adhesive skin layer until use.
  • a method of using an adhesive-coated article comprising providing an article as described herein and adhering the pressure sensitive adhesive to a surface.
  • the multilayer pressure sensitive adhesive is particularly useful for adhering to rough surfaces, such as orange peel drywall.
  • the present disclosure describes pressure sensitive adhesive ("PSA") coated articles.
  • the storage modulus of a pressure sensitive adhesive at the application temperature is less than 3 x 10 6 dynes/cm 2 at a frequency of 1 Hz.
  • the adhesive is a pressure sensitive adhesive at an application temperature that is greater than room temperature.
  • the application temperature may be 30, 35, 40, 45, 50, 55, or 65°C.
  • the storage modulus of the pressure sensitive adhesive at room temperature (25°C) is typically greater than 3 x 10 6 dynes/cm 2 at a frequency of 1 Hz.
  • the storage modulus of the pressure sensitive adhesive at room temperature (25°C) is less than 2 x 10 6 dynes/cm 2 or 1 x 10 6 dynes/cm 2 at a frequency of 1 Hz.
  • “Syrup composition” refers to a solution of a solute polymer in one or more solvent monomers, the composition having a viscosity from 100 to 8,000 cPs at 25°C. The viscosity of the syrup is greater than the viscosity of the solvent monomer(s).
  • (meth)acryloyl is inclusive of (meth)acrylate and (meth)acrylamide.
  • (meth) acrylic includes both methacrylic and acrylic.
  • (meth)acrylate includes both methacrylate and acrylate.
  • alkyl includes straight-chained, branched, and cyclic alkyl groups and includes both unsubstituted and substituted alkyl groups. Unless otherwise indicated, the alkyl groups typically contain from 1 to 20 carbon atoms.
  • alkyl examples include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, isobutyl, t-butyl, isopropyl, n-octyl, 2-octyl, n-heptyl, ethylhexyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, and norbornyl, and the like. Unless otherwise noted, alkyl groups may be mono- or polyvalent.
  • heteroalkyl refers to an alkyl group, as just defined, having at least one catenary carbon atom (i.e. in-chain) replaced by a catenary heteroatom such as O, S, or N.
  • olefin group refers to an unsaturated aliphatic straight-chained, branched, or cyclic (i.e. unsubstitued) hydrocarbon group having one or more double bonds. Those containing one double bond are commonly called alkenyl groups.
  • the olefin group may further comprise substituents as will subsequently be described.
  • the olefin group is typically monovalent.
  • renewable resource refers to a natural resource that can be replenished within a 100 year time frame.
  • the resource may be replenished naturally or via agricultural techniques.
  • the renewable resource is typically a plant (i.e. any of various photosynthetic organisms that includes all land plants, inclusive of trees), organisms of Protista such as seaweed and algae, animals, and fish. They may be naturally occurring, hybrids, or genetically engineered organisms. Natural resources such as crude oil, coal, and peat which take longer than 100 years to form are not considered to be renewable resources.
  • each group is present more than once in a formula described herein, each group is
  • the pressure sensitive adhesive coated articles comprise a pressure sensitive adhesive disposed on a substrate.
  • the substrate may be a backing or a release liner.
  • the adhesive is a multilayer adhesive comprising at least two layers, a first adhesive layer and a second PSA skin layer disposed on the first adhesive layer.
  • the first adhesive layer is conformable.
  • the PSA film comprises at least the first adhesive layer and at an outermost (i.e. exposed) PSA skin layer.
  • the present invention is however not limited to two layers.
  • the multilayer PSA may comprise three, four, five or even more superimposed layers. In such an embodiment, it is preferred that the additional layers are beneath the second PSA skin layer.
  • the additional layers may be referred to as intermediate layer(s).
  • the multilayer adhesive may further comprise at least one intermediate adhesive layer between the first adhesive layer and the second PSA skin layer or between the first adhesive layer and the backing.
  • one embodied adhesive coated article 100 includes a substrate 1 10, such as a backing, comprising a first major surface 11 1 and a second opposing major surface 1 12.
  • a multilayer adhesive is disposed on the first major surface of the substrate.
  • the multilayer adhesive comprises a first (e.g. conformable) adhesive layer 120 disposed on the first major surface of the substrate.
  • Adhesive coated article 100 may be a single-faced tape further comprising a release liner (not shown) disposed on the exposed surface 131 of second PSA skin layer 130.
  • the adhesive coated article 200 in an unsupported (i.e. lacking a backing) multilayer PSA film.
  • the multilayer PSA film comprises a first adhesive layer 220 and a second PSA skin layer 230 disposed upon the first (e.g. conformable) adhesive layer.
  • Unsupported adhesive films typically having a thickness of at least 200 microns. Unsupported adhesive films are typically manufactured and provided between a pair of release liners (not shown).
  • another embodied adhesive coated article 300 includes a substrate 310, such as a backing, comprising a first major surface 31 1 and a second opposing major surface 312.
  • a multilayer adhesive is disposed on both the first major surface and the second opposing surface of the substrate.
  • the multilayer adhesive comprises a first (e.g. conformable) adhesive layer 320 is disposed on the first major surface of the substrate and a second PSA skin layer 330 is disposed upon the first layer 320.
  • PSA skin layers 330 are adhered to (e.g. different) surfaces.
  • Adhesive coated article 300 may be a double-faced tape further comprising a pair of release liners (not shown) disposed on the exposed surfaces 331 and 332 of the PSA skin layers 330.
  • another embodied adhesive coated article 400 includes a substrate 410, such as a backing, comprising a first major surface 41 1 and a second opposing major surface 412.
  • a multilayer adhesive is disposed on the first major surface of the substrate.
  • the multilayer adhesive comprises a first (e.g. conformable) adhesive layer 420 disposed on the first major surface of the substrate and a second PSA skin layer 430 is disposed upon the first layer.
  • Adhesive coated article 400 further comprises another adhesive layer 450 disposed on the second opposing major surface 412 of substrate (e.g. backing) 410.
  • Adhesive layer 450 may be a single layer adhesive, such as a permanent grade, non-removable pressure sensitive adhesive.
  • a permanent grade non-removable PSAs are known such as tackified rubber-based adhesive and various acrylic adhesives, as described for example in US Re 24,406; US 4,181,752; US 4,303,485; US 4,429,384; and US 4,330,590.
  • another embodied adhesive coated article 500 includes article 570, such as a hook.
  • a multilayer adhesive is disposed on the back surface 571 of the (e.g. hook) article in order that the article can be (e.g. removably) mounted to a surface by the multilayer PSA.
  • the multilayer PSA comprises a first (e.g. conformable) adhesive layer 520 is disposed on the first major surface of the substrate and a second PSA skin layer 530 disposed upon the first layer.
  • Adhesive coated article 500 may optionally further comprises an additional (e.g. permanent) adhesive layer (not shown) disposed between first adhesive layer 520 and article 570.
  • Adhesive coated article 500 may optionally further comprising a backing (not shown).
  • adhesive coated article 500 includes both an additional adhesive layer and backing; the adhesive coated article may be the same as FIG. 4 wherein adhesive layer 450 is bonded to an article.
  • the multilayer adhesive is an acrylic PSA; i.e. both the first and second layers are each acrylic PSAs.
  • the adhesive comprises a (meth)acrylic polymer prepared from one or more monomers common to acrylic adhesives, such as a (meth)acrylic ester monomers (also referred to as (meth)acrylate acid ester monomers and alkyl(meth)acrylate monomers) optionally in combination with one or more other monomers such as acid- functional ethylenically unsaturated monomers, non-acid-functional polar monomers, and vinyl monomers.
  • the monomers are polymerized by means of crosslinked (meth)acrylate linkages.
  • the adhesive is an acrylic pressure sensitive adhesive it is typically free of urethane linkages.
  • the (meth)acrylic polymer comprises one or more (meth)acrylate ester monomers derived from a (e.g. non-tertiary) alcohol containing from 1 to 14 carbon atoms and preferably an average of from 4 to 12 carbon atoms.
  • a (e.g. non-tertiary) alcohol containing from 1 to 14 carbon atoms and preferably an average of from 4 to 12 carbon atoms.
  • Examples of monomers include the esters of either acrylic acid or methacrylic acid with non- tertiary alcohols such as ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1 -pentanol, 2-pentanol, 3- pentanol, 2-methyl- 1 -butanol, 3 -methyl- 1-butanol, 1-hexanol, 2-hexanol, 2-methyl- 1 -pentanol, 3-methyl- 1 -pentanol, 2-ethyl- 1 -butanol, 3, 5,5-trimethyl- 1-hexanol, 3-heptanol, 1-octanol, 2-octanol,
  • a preferred (meth)acrylate ester monomer is the ester of (meth)acrylic acid with isooctyl alcohol.
  • the monomer is the ester of (meth)acrylic acid with an alcohol derived from a renewable source.
  • a suitable technique for determining whether a material is derived from a renewable resource is through 14 C analysis according to ASTM D6866-10, as described in US2012/0288692.
  • the application of ASTM D6866-10 to derive a "bio-based content" is built on the same concepts as radiocarbon dating, but without use of the age equations.
  • the analysis is performed by deriving a ratio of the amount of organic radiocarbon ( 14 C) in an unknown sample to that of a modern reference standard. The ratio is reported as a percentage with the units "pMC" (percent modern carbon).
  • 2-octyl (meth)acrylate As can be prepared by conventional techniques from 2-octanol and (meth)acryloyl derivatives such as esters, acids and acyl halides.
  • the 2-octanol may be prepared by treatment of ricinoleic acid, derived from castor oil, (or ester or acyl halide thereof) with sodium hydroxide, followed by distillation from the co-product sebacic acid.
  • Other (meth)acrylate ester monomers that can be renewable are those derived from ethanol and 2-methyl butanol.
  • the (e.g. pressure sensitive) adhesive composition e.g. (meth)acrylic polymer and/or free-radically polymerizable solvent monomer
  • the (e.g. pressure sensitive) adhesive composition comprises a bio-based content of at least 25, 30, 35, 40, 45, or 50 wt-% using ASTM D6866-10, method B.
  • the (e.g.) adhesive composition comprises a bio-based content of at least 25, 30, 35, 40, 45, or 50 wt-% using ASTM D6866-10, method B.
  • pressure sensitive) adhesive composition comprises a bio-based content of at least 55, 60, 65, 70, 75, or 80 wt-%.
  • the (e.g. pressure sensitive) adhesive composition comprises a bio- based content of at least 85, 90, 95, 96, 97, 99 or 99 wt-%.
  • the (e.g. pressure sensitive) adhesive comprises one or more low Tg (meth)acrylate monomers, having a Tg no greater than 10°C when reacted to form a homopolymer.
  • the low T g monomers have a Tg no greater than 0°C, no greater than -5°C, or no greater than - 10°C when reacted to form a homopolymer.
  • the Tg of these homopolymers is often greater than or equal to -80°C, greater than or equal to -70°C, greater than or equal to -60°C, or greater than or equal to -50°C.
  • the Tg of these homopolymers can be, for example, in the range of -80°C to 20°C, -70°C to 10°C, -60°C to 0°C, or -60°C to - 10°C.
  • the low Tg monomer may have the formula
  • H 2 C CR 1 C(0)OR 8 wherein R 1 is H or methyl and R 8 is an alkyl with 1 to 22 carbons or a heteroalkyl with 2 to 20 carbons and 1 to 6 heteroatoms selected from oxygen or sulfur.
  • the alkyl or heteroalkyl group can be linear, branched, cyclic, or a combination thereof.
  • Exemplary low Tg monomers include for example ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2- methylbutyl acrylate, 2-ethylhexyl acrylate, 4-methyl-2-pentyl acrylate, n-octyl acrylate, 2-octyl acrylate, isooctyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate, lauryl acrylate, isotridecyl acrylate, octadecyl acrylate, and dodecyl acrylate.
  • Low Tg heteroalkyl acrylate monomers include, but are not limited to, 2-methoxyethyl acrylate and 2-ethoxyethyl acrylate.
  • the (e.g. pressure sensitive) adhesive (e.g. (meth)acrylic polymer and/or free radically polymerizable solvent monomer) comprises low Tg monomer(s) having an alkyl group with 6 to 20 carbon atoms.
  • the low Tg monomer has an alkyl group with 7 or 8 carbon atoms.
  • Exemplary monomers include, but are not limited to, 2-ethylhexyl methacrylate, isooctyl methacrylate, n-octyl methacrylate, 2-octyl methacrylate, isodecyl methacrylate, and lauryl methacrylate.
  • some heteroalkyl methacrylates such as 2-ethoxy ethyl methacrylate can also be used.
  • the (e.g. pressure sensitive) adhesive e.g. (meth)acrylic polymer and/or free-radically polymerizable solvent monomer
  • the (e.g. pressure sensitive) adhesive comprises a high Tg monomer, having a Tg greater than 10 °C and typically of at least 15 °C, 20 °C or 25°C, and preferably at least 50°C.
  • Suitable high Tg monomers include, for example, t-butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, stearyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, norbornyl (meth) acrylate, benzyl methacrylate, 3,3,5 trimethylcyclohexyl acrylate, cyclohexyl acrylate, N-octyl acrylamide, and propyl methacrylate or combinations.
  • the (meth)acrylic polymer is a homopolymer. In other embodiments, the (meth)acrylic polymer is a copolymer. Unless specified otherwise, the term polymer refers to both a homopolymer and copolymer.
  • the Tg of the copolymer may be estimated by use of the Fox equation, based on the Tgs of the constituent monomers and the weight percent thereof.
  • the alkyl (meth)acrylate monomers are typically present in the (meth)acrylic polymer in an amount of at least 85, 86, 87, 88, 89, or 90 up to 95, 96, 97, 98, or 99 parts by weight, based on 100 parts by weight of the total monomer or polymerized units.
  • the adhesive may include at least 5, 10, 15, 20, to 30 parts by weight of such high Tg monomer(s).
  • the (e.g. pressure sensitive) adhesive composition is free of unpolymerized components, such as tackifier, silica, and glass bubbles, the parts by weight of the total monomer or polymerized units is approximately the same as the wt-% present in the total adhesive composition.
  • the (e.g. pressure sensitive) adhesive composition comprises such unpolymerized components, the (e.g.
  • pressure sensitive adhesive composition can comprises substantially less alkyl(meth)acrylate
  • the (e.g. pressure sensitive) adhesive composition comprises at least 50 wt-% of polymerized units derived from alkyl (meth)acrylate monomers. In some embodiments, the pressure sensitive adhesive composition comprises at least 50, 55, 60, 65, 70, 75, 80, 85, or 90 wt-% of one or more low Tg monomers.
  • Acrylic pressure sensitive adhesives often comprise an acid functional monomer (a subset of high Tg monomers), where the acid functional group may be an acid per se, such as a carboxylic acid, or a portion may be salt thereof, such as an alkali metal carboxylate.
  • acid functional monomers include, but are not limited to, those selected from ethylenically unsaturated carboxylic acids, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphonic acids, and mixtures thereof.
  • Such compounds include those selected from acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, citraconic acid, maleic acid, oleic acid, ⁇ -carboxyethyl (meth)acrylate, 2- sulfoethyl methacrylate, styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylphosphonic acid, and mixtures thereof.
  • the inclusion of acid functional monomers can affect the peel adhesion by causing the peel adhesion to increase upon aging.
  • a multilayer adhesive composition that is initially cleanly removable can become not cleanly removable upon aging.
  • at least the second PSA skin layer and preferably also the first layer as well as the entire multilayer adhesive comprises little or no acid functional monomers.
  • combination with the first layer or entire multilayer PSA comprises less than 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 or 0 wt-% of polymerized units derived from acid- functional monomers such as acrylic acid.
  • Acrylic pressure sensitive adhesives can optionally comprise other monomers such as a non-acid- functional polar monomer.
  • suitable polar monomers include but are not limited to 2-hydroxyethyl (meth)acrylate; N-vinylpyrrolidone; N-vinylcaprolactam; acrylamide; mono- or di-N-alkyl substituted acrylamide; t-butyl acrylamide; dimethylaminoethyl acrylamide; N-octyl acrylamide; poly(alkoxyalkyl) (meth)acrylates including 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2- ethoxyethyl (meth)acrylate, 2-methoxyethoxyethyl (meth)acrylate, 2-methoxyethyl methacrylate, polyethylene glycol mono(meth)acrylates; alkyl vinyl ethers, including vinyl methyl ether; and mixtures thereof.
  • Preferred polar monomers include those selected from the group consisting of 2-hydroxyethyl (meth)acrylate and N-vinylpyrrolidinone.
  • non-acid- functional polar monomer may be present in amounts of 0 to 10 parts by weight, or 0.5 to 5 parts by weight, based on 100 parts by weight total monomer.
  • the multilayer pressure sensitive adhesive comprises less than 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 or 0 wt-% of polymerized units derived from non-acid polar monomers.
  • Acrylic pressure sensitive adhesives can optionally comprise vinyl monomers including vinyl esters (e.g., vinyl acetate and vinyl propionate), styrene, substituted styrene (e.g., a-methyl styrene), vinyl halide, and mixtures thereof.
  • the multilayer pressure sensitive adhesive comprises less than 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 or 0 wt-% of polymerized units derived from vinyl monomers.
  • the first and second layers of the multilayer PSA are generally crosslinked with a crosslinking monomer.
  • the crosslinking monomer is selected such that is does not form corrosive by-products and has good color stability.
  • the pressure sensitive adhesive is free of crosslinkers such as aziridine crosslinkers, chlorinated triazine crosslinkers, melamine crosslinkers.
  • the concentration of crosslinking monomer is typically at least 0.1, 0.2, 0.3, 0.4 or 0.5 wt-% and can range up to 10, 1 1, 12, 13, 14, or 15 wt-%. However, as the concentration of such crosslinking monomer increases, the peel adhesion (180° to stainless steel) can decrease. Thus, in typically embodiments, the concentration of such crosslinking monomer is no greater than 9, 8, 7, 6, or 5 wt-% and in some favored embodiments, no greater than 4, 3, 2, or 1 wt-%.
  • the concentration of crosslmking monomer in the second adhesive skin layer is typically greater than that of the first (e.g. conformable) layer.
  • the weight ratio of crosslinker of the first adhesive layer to second adhesive skin layer may be at least 1 : 1.5 or 1 :2 or 1 :2.5 or 1 :3 ranging up to 1 : 10 or 1 :9 or 1 :8.
  • the (e.g. pressure sensitive) adhesive composition may comprise a single crosslmking monomer, or a combination of two or more crosslinking monomers. Further, the crosslmking monomer may comprise two or more isomers of the same general structure.
  • both the first adhesive layer and second PSA skin layer of the multilayer PSA each comprise a multifunctional (meth)acrylate.
  • a multifunctional (meth)acrylate may be the sole crosslinking monomer of the first and second layer, as well as the multilayer PSA.
  • the second PSA skin layer of the multilayer PSA comprises a multifunctional
  • both the first adhesive layer and second PSA skin layer of the multilayer PSA each comprise a crosslinking monomer comprising at least one C3-C20 olefin group.
  • a crosslinking monomer comprising at least one C3-C20 olefin group may be the sole crosslinking monomer of the first and second layer, as well as the multilayer PSA.
  • the crosslinking monomer is a multifunctional (meth)acrylate.
  • the pressure sensitive adhesive comprises include, but are not limited to, di(meth)acrylates, tri(meth)acrylates, and tetra(meth)acrylates, such as 1 ,6-hexanediol di(meth)acrylate, poly(ethylene glycol) di(meth)acrylates, polybutadiene di(meth)acrylate, polyurethane di(meth)acrylates, and propoxylated glycerin tri(meth)acrylate, and mixtures thereof.
  • the multifunctional multifunctional poly(meth)acrylates such as 1 ,6-hexanediol di(meth)acrylate, poly(ethylene glycol) di(meth)acrylates, polybutadiene di(meth)acrylate, polyurethane di(meth)acrylates, and propoxylated glycerin tri(meth)acrylate, and mixtures thereof.
  • (meth)acrylate is not part of the original monomer mixture, but added subsequently after the formation of the (meth)acrylic polymer.
  • At least one adhesive layer or the multilayer PSA comprises predominantly
  • the lower reactivity of the C3- C20 olefin group, as compared to a (meth)acrylate group, can be amendable to achieving an optical amount of crosslinking, especially when the adhesive is cured by (e.g. UV) radiation.
  • a crosslinking monomer that comprises one or more C3-C20 olefin groups.
  • At least the first adhesive layer or the multilayer PSA may be free of multifunctional
  • (meth)acrylate crosslinkers such as tripropylene glycol diacrylate and 1,6-hexanediol diacrylate (HDDA) depicted as follows:
  • the crosslinking monomer comprises a (meth)acrylate group and a C6-C20 olefin group.
  • the olefin group comprises at least one hydrocarbon unsaturation. In some embodiments, the olefin group comprises substituents.
  • the crosslinking monomer may have the formula
  • Rl is H or CH 3 ,
  • L is an optional linking group
  • R2 is a C6-C20 olefin group, the olefin group being optionally substituted.
  • the C6-C20 olefin group is an unsaturated aliphatic straight-chained, branched, or cyclic (e.g. unsubstituted) hydrocarbon group having one or more double bonds. Those containing one double bond are commonly called alkenyl groups.
  • the linking group typically has a molecular weight no greater than 1000 g/mole and in some embodiments no greater than 500 g/mole, 400 g/mole, 300 g/mole, 200 g/mole, 100 g/mole, or 50 g/mole.
  • L comprises or consists of alkylene (e.g. ethylene) oxide repeat units.
  • alkylene e.g. ethylene
  • Such crosslinking monomer can be derived from reacting an ethoxylated alcohol with acryloyl chloride, methylene chloride and triethylamine, or by direct esterfication with acrylic acid.
  • the crosslinking monomer comprises a (meth)acrylate group and an optionally substituted C6-C20 olefin group comprising a terminal hydrocarbon unsaturation.
  • the hydrocarbon unsaturation has the formula:
  • R 3 C CR 4 R 5 wherein R 4 and R 5 are H and R 3 is H or (e.g. C1-C4) alkyl.
  • Undecenyl (meth)acrylate includes such terminal unsaturation.
  • the crosslinking monomer comprises a (meth)acrylate group and an optionally substituted C6-C20 olefin group comprising at least one hydrocarbon unsaturation in the backbone of the optionally substituted C6-C20 olefin group.
  • the hydrocarbon unsaturation has the formula:
  • R 4 and R 5 are independently alkyl and R 3 is H or (e.g. C1-C4) alkyl. In some embodiments, R 4 and R 5 are each methyl. In this embodiment, R 4 or R 5 is the terminal alkyl group of the C6-C 2 0 olefin group.
  • Citronellyl (meth)acrylate, geraniol (meth)acrylate and farnesol (meth)acrylate include a hydrocarbon unsaturation of this type.
  • crosslmking monomer comprising a (meth)acrylate group and an optionally substituted Ce- C 20 olefin group comprising a terminal hydrocarbon unsaturation are described in PCT/US 14/33712, filed April 1 1 , 2014, incorporated herein by reference.
  • Illustrative crosslmking monomers include for example geraniol (meth)acrylate (e.g. 3,7-dimethylocta-2,6-dienyl] prop-2-enoate), farnesol (meth)acrylate (e.g. 3,7, 1 1 -trimethyldodeca-2,6, 10-trienyl] prop-2-enoate) and oleyl (meth)acrylate.
  • the crosslmking monomer comprises at least two terminal groups selected from allyl, methallyl, or combinations thereof.
  • An allyl group has the structural formula
  • the crosslmking monomers are typically free of vinyl groups, such as vinyl esters or vinyl ethers.
  • the crosslmking monomer comprises two (meth)allyl groups and a
  • (meth)acrylate group A crosslmking monomer of this type is commercially available from Sartomer, under the trade designation "SR 523". However, in typical embodiments, the crosslmking monomer is free of (meth)acrylate groups.
  • crosslinking monomer comprising at least two terminal groups selected from allyl,
  • Z is a heteroatom or multivalent linking group
  • x ranges from 2 to 6.
  • x is 2 or 3. In some embodiments, y is 5-20.
  • the linking group Z typically has a molecular weight no greater than 1000 g/mole and in some embodiments no greater than 500 g/mole, 400 g/mole, 300 g/mole, 200 g/mole, 100 g/mole, or 50 g/mole.
  • Z can be a heteratom, such as oxygen; as well as a wide variety of multivalent (di-, tri-, tetra- penta-, and hexa-) linking groups.
  • Z can comprise alkylene, arylene, ester, ether, amide, urethane, urea, amine, carbonate, silane, cyanurate, and combinations thereof.
  • Z comprises only one of such multivalent linking groups.
  • Z comprises more than one of the same class of multivalent linking groups (e.g. diester, triether).
  • Z comprises combinations of different classes of multivalent linking groups such as an ester or ether and an alkylene or arylene group.
  • Z is a reaction product of a multifunctional alcohol having 2 to 6 hydroxyl groups.
  • the crosslinking monomer typically has the formula
  • L 2 is a linear or branched (C1-C12) alkylene optionally comprising one or more substituents such as hydroxyl groups or alkoxy groups;
  • x ranges from 2 to 6;
  • R 3 is hydrogen or methyl.
  • x is at least 2, such as in the case of butane diol (meth)ally ether. In other embodiments, x is at least 3 and L 2 is a residue of a multifunctional alcohol such as glycerol,
  • trimethylolpropane trimethylolpropane ethoxylate, trimethylolpropane propoxylate, pentaerythritol, 1 ,2,4-butanetriol, 1 , 1 , 1 -tris(hydroxymethyl)ethane, fructose, glucose, l,3,5-tris(2- hydroxyethyl)isocyanurate, dipentaerythritol, and di(trimethylolpropane).
  • crosslinking monomers include for example pentaerythritol allyl ether and trimethylolpropane diallyl ether (TMPDE), depicted as follows:
  • the (meth)acrylic copolymers and pressure sensitive adhesive composition can be polymerized by various techniques including, but not limited to, solvent polymerization, dispersion polymerization, solventless bulk polymerization, and radiation polymerization, including processes using ultraviolet light, electron beam, and gamma radiation.
  • the monomer mixture may comprise a polymerization initiator, especially a thermal initiator or a photoinitiator of a type and in an amount effective to polymerize the comonomers.
  • One preferred method of preparing (meth)acrylic polymers includes partially polymerizing monomers to produce a syrup composition comprising the solute (meth)acrylic polymer and
  • the unpolymerized solvent monomer(s) typically comprises the same monomer as utilized to produce the solute (meth)acrylic polymer. If some of the monomers were consumed during the polymerization of the (meth)acrylic polymer, the unpolymerized solvent monomer(s) comprises at least some of the same monomer(s) as utilized to produce the solute
  • (meth)acrylic polymer (meth)acrylic polymer. Further, the same monomer(s) or other monomer(s) can be added to the syrup once the (meth)acrylic polymer has been formed. Partial polymerization provides a coatable solution of the (meth)acrylic solute polymer in one or more free-radically polymerizable solvent monomers. The partially polymerized composition is then coated on a suitable substrate and further polymerized.
  • the crosslinking monomer is added to the monomer(s) utilized to form the (meth)acrylic polymer.
  • the crosslinking monomer may be added to the syrup after the (meth)acrylic polymer has been formed.
  • One of the (meth)allyl groups of the crosslinker and other (e.g. (meth)acrylate) monomers utilized to form the (meth)acrylic polymer polymerize forming an acrylic backbone with the pendent (meth)allyl group.
  • the pressure sensitive adhesive composition can be characterized as comprising the reaction product of a free-radically polymerizable syrup comprising
  • a solute (meth)acrylic polymer comprising polymerized units derived from one or more alkyl (meth)acrylate monomers
  • syrup comprises at least one crosslinking monomer (as previously described) or the
  • (meth)acrylic solute polymer comprises polymerized units derived from at least one crosslinking monomer (as previously described).
  • the syrup method provides advantages over solvent or solution polymerization methods; the syrup method yielding higher molecular weight materials. These higher molecular weights increase the amount of chain entanglements, thus increasing cohesive strength. Also, the distance between cross-links can be greater with high molecular syrup polymer, which allows for increased wet-out onto a surface.
  • Polymerization of the (meth)acrylate solvent monomers can be accomplished by exposing the syrup composition to energy in the presence of a photoinitiator. Energy activated initiators may be unnecessary where, for example, ionizing radiation is used to initiate polymerization.
  • a photoinitiator can be employed in a concentration of at least 0.0001 part by weight, preferably at least 0.001 part by weight, and more preferably at least 0.005 part by weight, relative to 100 parts by weight of the syrup.
  • a preferred method of preparation of the syrup composition is photoinitiated free radical polymerization.
  • Advantages of the photopolymerization method are that 1) heating the monomer solution is unnecessary and 2) photoinitiation is stopped completely when the activating light source is turned off. Polymerization to achieve a coatable viscosity may be conducted such that the conversion of monomers to polymer is up to about 30%. Polymerization can be terminated when the desired conversion and viscosity have been achieved by removing the light source and by bubbling air (oxygen) into the solution to quench propagating free radicals.
  • the solute polymer(s) may be prepared conventionally in a non- monomeric solvent and advanced to high conversion (degree of polymerization). When solvent
  • the solvent may be removed (for example by vacuum distillation) either before or after formation of the syrup composition. While an acceptable method, this procedure involving a highly converted functional polymer is not preferred because an additional solvent removal step is required, another material may be required (a non-monomeric solvent), and dissolution of the high molecular weight, highly converted solute polymer in the monomer mixture may require a significant period of time.
  • the polymerization is preferably conducted in the absence of solvents such as ethyl acetate, toluene and tetrahydrofuran, which are non-reactive with the functional groups of the components of the syrup composition.
  • Solvents influence the rate of incorporation of different monomers in the polymer chain and generally lead to lower molecular weights as the polymers gel or precipitate from solution.
  • the (e.g. pressure sensitive) adhesive can be free of unpolymerizable organic solvent.
  • Useful photoinitiators include benzoin ethers such as benzoin methyl ether and benzoin isopropyl ether; substituted acetophenones such as 2,2-dimethoxy-2-phenylacetophenone photoinitiator, available the trade name IRGACURE 651 or ESACURE KB-1 photoinitiator (Sartomer Co., West Chester, PA), and dimethylhydroxyacetophenone; substituted a-ketols such as 2- methyl-2-hydroxy propiophenone; aromatic sulfonyl chlorides such as 2-naphthalene-sulfonyl chloride; and photoactive oximes such as 1- phenyl-l,2-propanedione-2-(0-ethoxy-carbonyl)oxime. Particularly preferred among these are the substituted acetophenones.
  • Preferred photoinitiators are photoactive compounds that undergo a Norrish I cleavage to generate free radicals that can initiate by addition to the acrylic double bonds.
  • the photoinitiator can be added to the mixture to be coated after the polymer has been formed, i.e., photoinitiator can be added to the syrup composition.
  • Such polymerizable photoinitiators are described, for example, in U.S. 5,902,836 and 5,506,279 (Gaddam et al.).
  • Such photoinitiators preferably are present in an amount of from 0.1 to 1.0 part by weight, relative to 100 parts by weight of the total syrup content. Accordingly, relatively thick coatings can be achieved when the extinction coefficient of the photoinitiator is low.
  • the syrup composition and the photoinitiator may be irradiated with activating UV radiation to polymerize the monomer component(s).
  • UV light sources can be of two types: 1) relatively low light intensity sources such as blacklights, which provide generally 10 mW/cm 2 or less (as measured in accordance with procedures approved by the United States National Institute of Standards and
  • the degree of conversion can be monitored during the irradiation by measuring the index of refraction of the polymerizing medium as previously described.
  • Useful coating viscosities are achieved with conversions (i.e., the percentage of available monomer polymerized) in the range of up to 30%, preferably 2% to 20%, more preferably from 5% to 15%, and most preferably from 7% to 12%.
  • the molecular weight (weight average) of the solute polymer(s) is typically at least 100,000; 250,000;
  • One favored method of preparing a pressure sensitive adhesive composition comprises a) providing a syrup comprising
  • a solute (meth)acrylic polymer comprising polymerized units derived from one or more alkyl (meth)acrylate monomers
  • syrup comprises at least one crosslinking monomer (as previously described) or the
  • (meth)acrylic solute polymer comprises polymerized units derived from at least one crosslinking monomer (as previously described);
  • the pressure sensitive adhesives may optionally contain one or more conventional additives.
  • Preferred additives include tackifiers, plasticizers, dyes, antioxidants, UV stabilizers, and (e.g. inorganic) fillers such as (e.g. fumed) silica and glass bubbles.
  • the multilayer adhesive typically comprises fumed silica (e.g. 221 of FIG. 2).
  • Fumed silica also known as pyrogenic silica, is made from flame pyrolysis of silicon tetrachloride or from quartz sand vaporized in a 3000°C electric arc.
  • Fumed silica consists of microscopic droplets of amorphous silica fused into (e.g. branched) three-dimensional primary particles that aggregate into larger particles. Since the aggregates do not typically break down, the average particle size of fumed silica is the average particle size of the aggregates.
  • Fumed silica is commercially available from various global producers including Evonik, under the trade designation "Aerosil”; Cabot under the trade designation “Cab-O-Sil", and Wacker Chemie-Dow Corning.
  • the BET surface area of suitable fumed silica is typically at least 50 m 2 /g, or 75 m 2 /g, or 100 m 2 /g. In some embodiments, the BET surface area of the fumed silica is no greater than 400 m 2 /g, or 350 m 2 /g, or 300 m 2 /g, or 275 m 2 /g, or 250 m 2 /g.
  • the fumed silica aggregates preferably comprise silica having a primary particle size no greater than 20 nm or 15 nm. The aggregate particle size is substantially larger than the primary particle size and is typically at least 100 nm or greater.
  • the concentration of (e.g. fumed) silica can vary.
  • the second PSA skin layer comprises at least 5, 6, 7, 8, 9, or 10 wt-% of (e.g. fumed) silica and typically no greater than 20, 19, 18, 17, 16, or 15 wt-% of (e.g. fumed) silica.
  • the first layer of the multilayer adhesive may comprise less silica than the skin layer.
  • the first layer comprises at least 0.5, 1. 0, 1.1, 1.2, 1.3, 1.4, or 1.5 wt-% of (e.g. fumed) silica and in some embodiments no greater than 5, 4, 3, or 2 wt-%.
  • the adhesive typically comprises glass bubbles (e.g. 226 of FIG. 2).
  • Suitable glass bubbles generally have a density ranging from about 0.125 to about 0.35 g/cc. In some embodiments, the glass bubbles have a density less than 0.30, 0.25, or 0.20 g/cc.
  • Glass bubbles generally have a distribution of particles sizes. In typical embodiments, 90% of the glass bubbles have a particle size (by volume) of at least 75 microns and no greater than 1 15 microns. In some embodiments, 90% of the glass bubbles have a particle size (by volume) of at least 80, 85, 90, or 95 microns. In some embodiments, the glass bubbles have a crush strength of at least 250 psi and no greater than 1000, 750, or 500 psi. Glass bubbles are commercially available from various sources including 3M, St. Paul, MN.
  • the concentration of glass bubbles can vary.
  • the first adhesive layer of the multilayer adhesive comprises at least 1, 2, 3, 4 or 5 wt-% of glass bubbles and typically no greater than 20, 15, or 10 wt-% of glass bubbles.
  • the second skin layer of the multilayer adhesive may comprise less glass bubbles than the first conformable layer. In some embodiments, the second skin layer is free of glass bubbles.
  • glass bubbles can reduce the density of the adhesive.
  • Another way of reducing the density of the adhesive is by incorporation of air or other gasses into the adhesive composition.
  • 226 can represent a bubble created by gas rather than a glass bubble.
  • adhesive may contain both glass bubbles and bubbles created by gas
  • the (e.g. syrup) adhesive composition can be transferred to a frother as described for examples in U.S. Patent No. 4,415,615; incorporated herein by reference. While feeding nitrogen gas into the frother, the frothed syrup can be delivered to the nip of a roll coater between a pair of transparent, (e,g, biaxially-oriented polyethylene terephthalate) films.
  • a silicone or fluorochemical surfactant is included in the froathed syrup.
  • Various surfactants are known including copolymer surfactants described in U. S. Patent No. 6,852,781.
  • the multilayer pressure sensitive adhesive may optionally contain one or more conventional additives such as tackifiers, plasticizers, dyes, antioxidants, UV stabilizers.
  • the concentration can range from 5 or 10 wt-% to 40, 45, 50, 55, or 60 wt-% of the (e.g. cured) adhesive composition.
  • tackifiers include phenol modified terpenes and rosin esters such as glycerol esters of rosin and pentaerythritol esters of rosin that are available under the trade designations "Nuroz”, “Nutac” (Newport Industries), “Permalyn”, “Staybelite”, “Foral” (Eastman). Also available are hydrocarbon resin tackifiers that typically come from C5 and C9 monomers by products of naphtha cracking and are available under the trade names "Piccotac", “Eastotac”, “Regalrez”, "Regalite”
  • the pressure sensitive adhesive can be formulated to have a wide variety of properties for various end uses.
  • the adhesive composition and thickness is chosen to provide a synergistic combination of properties.
  • the adhesive can be characterized as having any one or combination of attributes including being conformable, cleanly removable, reusable, reactivatible, and exhibiting good adhesion to rough surfaces.
  • the first adhesive layer is conformable.
  • the conformability of an adhesive composition can be characterized using various techniques such as dynamic mechanical analysis (as determined by the test method described in the examples) that can be utilized to determine that shear loss modulus (G"), the shear storage modulus (G'), and tan delta, defined as the ratio of the shear loss modulus (G") to the shear storage modulus (G').
  • conformable refers to the first adhesive exhibiting a tan delta of at least 0.4 or greater at 25°C and 1 hertz.
  • the first adhesive has tan delta of at least 0.45, 0.50, 0.55, 0.65, or 0.70 at 25°C and 1 hertz.
  • the tan delta at 25°C and 1 hertz of the first adhesive is typically no greater than 0.80 or 1.0. In some embodiments, the tan delta of the first adhesive is no greater than 1.0 at 1 hertz and temperatures of 40°C, 60°C, 80°C, 100°C and 120°C. In some embodiments, the first adhesive has tan delta of at least 0.4 or greater at 1 hertz and temperatures of 40°C, 60°C, 80°C, 100°C and 120°C.
  • the second skin adhesive is typically stiffer, i.e. less conformable that the first adhesive.
  • the second skin adhesive has tan delta less than the first adhesive at 25°C by at least 0.5, 1.0, 1.5, 2.0, 2.5 or 3.0.
  • the second skin adhesive typically has a tan delta of less than 0.4 at 25°C and typically at least 0.2.
  • the tan delta of the second skin adhesive is less than 0.4 or 0.35 at temperatures of 40°C, 60°C, 80°C, 100°C and 120°C.
  • the second skin adhesive has a tan delta ranging from about 0.1 to 0.2 of at least 0.4 at 80°C, 100°C and 120°C.
  • the second skin adhesive typically has a higher crosslinking density than the first conformable adhesive layer, such as can be accomplished by use of a different crosslinker and/or a higher
  • the first adhesive layer is typically substantially thicker than the second skin layer. Since the bulk of the multilayer adhesive is the first adhesive layer, the multilayer adhesive conforms to rough surfaces in a similar manner as the first adhesive layer, yet cab adhere more aggressively by inclusion of the second skin layer.
  • the multilayer PSA and adhesive coated articles can exhibit good adhesion to both smooth and rough surfaces.
  • Various rough surfaces are known including for example, standard drywall, textured drywall, such as “knock down” and “orange peel”; cinder block, rough (e.g. Brazilian) tile and textured cement.
  • Smooth surfaces such as stainless steel, glass, and polypropylene have an average surface roughness (Ra) as can be measured by optical inferometry of less than 100 nanometer; whereas rough surfaces have an average surface roughness greater than 1 micron (1000 nanometers), 5 microns, or 10 microns.
  • Standard (untextured) drywall has an average surface roughness (Ra), of about 10-20 microns and a maximum peak height (Rt using Veeco's Vison software) of 150 to 200 microns.
  • Orange peel and knockdown drywall have an average surface roughness (Ra) greater than 20, 25, 30, 35, 40, or 45 microns and a maximum peak height (Rt) greater than 200, 250, 300, 350, or 400 microns.
  • Orange peel drywall can have an average surface roughness (Ra) of about 50-75 microns and a maximum peak height (Rt) of 450-650 microns.
  • Knock down drywall can have an average surface roughness (Ra) greater than 75, 80, or 85 microns, such as ranging from 90- 120 microns and a maximum peak height (Rt) of 650-850 microns.
  • Ra is no greater than 200, 175, or 150 microns and Rt is no greater than 1500, 1250, or 1000 microns.
  • Cinder block and Brazilian tile typically have a similar average surface roughness (Ra) as orange peel drywall.
  • the multilayer PSA and articles described herein can exhibit a shear (with a mass of 250g) to orange peel dry wall of at least 500 minutes. In some embodiments, the multilayer PSA and articles exhibits a shear (with a mass of 250g) to orange peel dry wall of at least 1000, 5000, 10000, 15000, or 20000 minutes.
  • the multilayer PSA and adhesive coated articles are cleanly removable from paper. By “cleanly removable from paper” it is meant that the paper does not tear and the paper does not have any staining or adhesive residue after removal of the adhesive from the paper when tested (according to Test Method 1 set forth in the examples).
  • the 90° peel values to paper is typically at least 25 and no greater than 200 or 175 N/dm. In some embodiments, the 90° peel value to paper no greater than 50, 45, or 40 N/dm.
  • the inclusion of the skin layer prevents excessive penetration of the conformable first layer into the paper which in tear can result in the paper tearing and not being cleaning removable.
  • the multilayer PSA and adhesive coated articles are reusable. By reuseable it is meant that multilayer PSA and/or article can repeatedly be removed and readhered at least 1, 2, 3, 4, or 5 times. In some embodiments, the adhesive coated backing or article can be readhered to paper at least 5, 10, 15, or 20 times while maintaining at least 80%, 85%, or 90% of the initial peel adhesion (according to the "Reusability" test further described in the examples).
  • the adhesive is reactivatible, i.e. contaminants can be removed by cleaning the adhesive layer(s) with soap and water, such as by the test methods described in WO 96/31564; incorporated herein by reference.
  • the multilayer adhesive can be applied to a substrate by various methods as described in the art. See for example U.S. Patent No. 4,818,610 and WO 201 1/09438.
  • the adhesives of the present invention may be coated upon a variety of flexible and inflexible backing materials using conventional coating techniques to produce adhesive-coated materials.
  • Flexible substrates are defined herein as any material which is conventionally utilized as a tape backing or may be of any other flexible material. Examples include, but are not limited to plastic films such as
  • Foam backings may be used.
  • the backing is comprised of a bio-based material such as polylactic acid (PLA).
  • Backings may also be prepared of fabric such as woven fabric formed of threads of synthetic or natural materials such as cotton, nylon, rayon, glass, ceramic materials, and the like or nonwoven fabric such as air laid webs of natural or synthetic fibers or blends of these.
  • the backing may also be formed of metal, metalized polymer films, or ceramic sheet materials may take the form of any article
  • pressure-sensitive adhesive compositions such as labels, tapes, signs, covers, marking indicia, and the like.
  • Backings can be made from plastics (e.g., polypropylene, including biaxially oriented polypropylene, vinyl, polyethylene, polyester such as polyethylene terephthalate), nonwovens (e.g., papers, cloths, nonwoven scrims), metal foils, foams (e.g., polyacrylic, polyethylene, polyurethane, neoprene), and the like.
  • Foams are commercially available from various suppliers such as 3M Co., Voltek, Sekisui, and others.
  • the foam may be formed as a coextruded sheet with the adhesive on one or both sides of the foam, or the adhesive may be laminated to it.
  • Suitable primers include for example those described in EP 372756, US 5534391, US 6893731, WO2011/068754, and WO201 1/38448.
  • the backing material is a transparent film having a transmission of visible light of at least 90 percent.
  • the transparent film may further comprise a graphic.
  • the adhesive may also be transparent.
  • compositions can be coated on a substrate using conventional coating techniques modified as appropriate to the particular substrate.
  • these compositions can be applied to a variety of solid substrates by methods such as roller coating, flow coating, dip coating, spin coating, spray coating knife coating, and die coating.
  • the composition may also be coated from the melt. These various methods of coating allow the compositions to be placed on the substrate at variable thicknesses thus allowing a wider range of use of the compositions. Coating thicknesses may vary as previously described.
  • the syrup composition may be of any desirable concentration for subsequent coating, but is typically 5 to 20 wt-% polymer solids in monomer. The desired concentration may be achieved by further dilution of the coating composition, or by partial drying.
  • Coating thicknesses of the cured coating may vary from about 25 (about 1 mil) to 1500 microns (60 mil). In typical embodiments, the coating thickness of the first layer ranges from about 20 to 40 mils; whereas the coating thickness of the second PSA skin ranges from about 1 to 5mils. When the multilayer PSA or article is intended to be bonded to a rough surface, the thickness of the adhesive layer typically ranges from the average roughness (Ra) to slightly greater than the maximum peak height (Rt).
  • the adhesive can also be provided in the form of a pressure-sensitive adhesive transfer tape in which at least one layer of the adhesive is disposed on a release liner for application to a permanent substrate at a later time.
  • the adhesive can also be provided as a single coated or double coated tape in which the adhesive is disposed on a permanent backing.
  • the side of the backing surface opposite that where the adhesive is disposed is typically coated with a suitable release material.
  • Release materials are known and include materials such as, for example, silicone, polyethylene, polycarbamate, polyacrylics, and the like.
  • another layer of adhesive is disposed on the backing surface opposite that where the adhesive of the invention is disposed.
  • the other layer of adhesive can be different from the adhesive of the invention, e.g., a conventional acrylic PSA, or it can be the same adhesive as the invention, with the same or a different formulation.
  • Double coated tapes are typically carried on a release liner. Additional tape constructions include those described in U.S. Pat. No.
  • test panels After applying the strips to the test panels, allow the panels samples to dwell at constant temperature and humidity (25 ° C/50% RH) room for 10 minutes before using an Instron tester. Fix the test panel and strip into the horizontal support. Set the machine at 305 mm per minute jaw separation rate. Test results were measured in gram force per inch and converted to Newtons per dm. The peel values are the average of three 90° angle peel measurements.
  • Reusability was determined by repeating this test method using the same adhesive sample with a fresh piece of paper each time wherein each reuse is considered a cycle.
  • the substrates employed were standard smooth drvwall obtained from Home Depot (Woodbury, MN). Knock-down and orange-peel drywall was prepared by IUPAT (International Union of Painters and Allied Trades, 3205 Country Drive, Little Canada, MN, USA). Drywall was primed using paint roller with Sherwin-Williams Pro-Mar 200. Surfaces were dried for a minimum of 4 hours at ambient conditions before applying next coat of paint.
  • White paint (Valspar Signature, Hi-def Advanced Color, Eggshell Interior, #221399, Ultra White / Base A) was applied to primed drywall using a new paint roller and allowed to dry at ambient conditions until tackless before applying a second coat of the same color.
  • Final painted drywall was dried overnight at ambient conditions and then placed into a 120°C oven for 1 week. Samples were removed from oven and cut into desired dimensions using draw knife. Samples were dusted off using Kim wipes, tissue, paper towels, or air (no cleaning with solvents) to remove dust left over from cutting before use in testing.
  • the sample area of adhesive bonded to the prepared drywall surface was 2.54 cm in the vertical direction by 2.54 cm in the width direction (rather than 1.27 cm by 1.27 cm as called for by the method). Then a 6.8 kg weight was placed on top of the bonded sample area for 1 minute. After a dwell time of 60 seconds, the test specimen was hung in the shear stand at desired temperature and loaded immediately with a 250 g weight. The time to failure for the adhesive bond was recorded in minutes. The test was discontinued at 20,000 minutes and samples that passed the test are reported as 20,000+ minutes.
  • Cinderblock was obtained from and cut down to 2" x 3" squares and 1 1 ⁇ 2" x 5" strips by Total Construction & Equipment, Inc. (10195 Inver Grove Trl, Inver Grove Heights, MN, USA). Cinderblock was primed using paint roller with Zinsser Bulls Eye 1 -2-3 ® (Rusto-Oleum Corp, 1 1 Hawthorn Pkwy, Vernon Hills, IL, USA). Surfaces were dried for a minimum of 4 hours at ambient conditions before applying next coat of paint.
  • White paint (Valspar Signature, Hi-def Advanced Color, Eggshell Interior, #221399, Ultra White / Base A) was applied to primed drywall using a new paint roller and allowed to dry at ambient conditions until tackless before applying a second coat of the same color. Final painted drywall was dried overnight at ambient conditions and then placed into a 120°C oven for 1 week.
  • Samples were removed from oven and cut into desired dimensions using draw knife. Samples were dusted off using Kim wipes, tissue, paper towels, or air (no cleaning with solvents) to remove dust left over from cutting before use in testing.
  • Tile was cleaned using a 50:50 (wt%) of Isopropyl alcohol : deioinized water mixture twice using Surpass tissues or Kim wipes.
  • Comparative Example A which is also the same as Adhesive Skin 1 (at 26.6 mil thickness) and examples 3-8 and 1 1-13 were analyzed by Dynamic Mechanical Analysis (DMA) using a Discovery Hybrid parallel plate rheometer (TA Instruments) to characterize the physical properties of each sample a function of temperature.
  • DMA Dynamic Mechanical Analysis
  • Rheology samples were prepared by punching out a section of the PSA with an 8 mm circular die, removing it from the release liners, centering it between 8 mm diameter parallel plates of the rheometer, and compressing until the edges of the sample were uniform with the edges of the top and bottom plates.
  • the furnace doors that surround the parallel plates and shafts of the rheometer were shut and the temperature was equilibrated at 20°C and held for 1 minute.
  • the temperature was then ramped from 20°C to 125 or 130°C at 3°C/min while the parallel plates were oscillated at an angular frequency of 1 Hertz and a constant strain of 5 percent.
  • Amounts of additives e.g., crosslinkers, photoinitiator, tackifiers, etc. are also expressed in parts per hundred resin (pph) in which 100 parts of the resin represents the total weight of the monomers that form the (meth)acrylic polymer, e.g., IOA, 20A, AA, with the exception of the crosslinking monomer.
  • pph parts per hundred resin
  • the weight % of the major components relative to the total adhesive composition is also reported.
  • Comparative A was prepared by charging a 500 mL jar with 350 g of IOA and 0.14 g (0.04 pph) of 651. The monomer mixture was purged with nitrogen for 10 minutes then exposed to low intensity UV A radiation until a coatable syrup was formed, after which another 0.70 g (0.20 pph) of 651 and 1.58 g SR 306 HP was added. Next, 52.5 g (15 pph) of trade designation Aerosil R972 fumed silica (Evonik Industries) were added and the syrup was mixed with a trade designation Netzsch Model 50 Dispersator, degassed, and jar rolled until used. The coated syrup was coated at a thickness of about 15 mils between a release liner and a primed 3 mil PET film and cured by UVA light with a total dosage of 1332 mJ/cm 2 . The average values of three samples were as follows:
  • Skin 1 - was prepared by charging a 500 mL jar with 350 g of IOA and 0.14 g (0.04 pph) of 651. The monomer mixture was purged with nitrogen for 10 minutes then exposed to low intensity UV A radiation until a coatable syrup was formed, after which another 0.70 g (0.20 pph) of 651 and 1.58 g SR 306HP was added. Next, 52.5 g (15 pph) of trade designation Aerosil R972 fumed silica (Evonik Industries) were added and the syrup was mixed with a trade designation Netzsch Model 50 Dispersator, degassed, and jar rolled until used.
  • Aerosil R972 fumed silica Evonik Industries
  • the wt-% of each of the major components of the total adhesive skin composition was as follows
  • Examples 1-8 were made by charging a quart jar with 300 g of low Tg monomer (IOA or 2-OA), 0.12 g of 651, and a quantity of crosslinker as shown in the following tables(TMPDE-90 and CiA, respectively).
  • the monomer mixture was purged with nitrogen for 5 minutes then exposed to low intensity ultraviolet radiation until a coatable syrup was prepared. Subsequently, 5.1 g of HDK HI 5 fumed silica was added, and the syrup was mixed with a Netzsch Model 50 Dispersator. An additional 0.57 g of 651 and 24 g of glass bubbles were then added. Pre-adhesive formulations were mixed thoroughly by rolling over night and degassed.
  • Adhesive Skin 1 composition and coatable syrup were coated sequentially between a release liner and a primed 3 mil PET film was in contact with the release liner and had a thickness of 2 mils and the coated syrup was in contact with the PET film and had a thickness of 22 mils.
  • UVA dosage, shear holding power and peel adhesion properties of resulting PSAs are shown in the following table.
  • the coatable syrup was coated at 25 mil thickness and cured in the same manner.
  • Samples were made by charging a gallon jar with 2000 g of 2-OA, and 0.8 g of 651. The monomer mixture was purged with nitrogen for 10 minutes then exposed to low intensity ultraviolet radiation until a coatable syrup was prepared. Subsequently, 34 g of HDK HI 5 fumed silica was added, and the syrup was mixed with a Netzsch Model 50 Dispersator. An additional 3.8 g of 651 and 160 g of glass bubbles were then added. The formulations were mixed thoroughly by rolling over night and degassed. A quart jar with 200 g of the compounded syrup was combined with the amount of HDDA indicated in the following table and rolled overnight.
  • the Adhesive Skin 1 composition and coatable syrup were coated sequentially between a release liner and a primed 3mil PET film such that the Adhesive Skin 1 was in contact with the release liner and had a thickness of 3 mils and the coated syrup was in contact with the PET film and had a thickness of 22 mils.
  • Light intensity during cure and shear holding power and creep properties of resulting PSAs are shown in the following table.
  • the coatable syrup was coated at 25 mil thickness and cured in the same manner.
  • K15 glass bubbles (8 pph) were then mixed into the syrup using Jiffy mixing blade at low rpm (-200-300). Final mixtures were measured for viscosity, degassed and rolled until coated.
  • Samples were frothed as described in U.S. Patent No. 4,415,615 using about 2-4 wt- % of the copolymer surfactant described in Example 44 of U.S. Patent No. 6,852,781.
  • the Adhesive Skin 1 composition and coatable syrup were coated sequentially between a release liner and a primed 3mil PET film such that the Adhesive Skin 1 was in contact with the release liner and had a thickness of 3 mils and the coated syrup was in contact with the PET film and cured by UVA light with a total dosage of 1482 mJ/cm 2 .
  • the coatable syrup was coated at 25 mil thickness and cured in the same manner.
  • the cured samples were then tested for peel, shear, density, and caliper (of the adhesive layers by subtraction of the thickness of the PET and release liner) as reported in the following table.
  • Samples were made by charging a gallon jar with 2000 g of 2-OA, and 0.8 g of 651. The monomer mixture was purged with nitrogen for 10 minutes then exposed to low intensity ultraviolet radiation until a coatable syrup was prepared. Subsequently, 34 g of HDK HI 5 fumed silica was added, 2.2 g of HDDA, and 3.8 g 651 were added to the syrup and mixed with a Netzsch Model 50 Dispersator. Next 160 g of glass bubbles were added and mixed thoroughly by rolling over night and degassed.
  • the Adhesive Skin 1 composition and coatable syrup were coated sequentially between a release liner and a primed 3mil PET film such that the Adhesive Skin 1 was in contact with the release liner and had a thickness of 3 mils and the syrup was in contact with the PET film and cured by 998 mW/cm 2 UVA light.
  • the syrup was coated at various thicknesses as indicated in the following table. The cured samples were then tested for peel, shear and caliper as reported in the following table.
  • Samples were made by charging a gallon jar with 2000 g of 2-OA, and 0.8 g of 651. The monomer mixture was purged with nitrogen for 10 minutes then exposed to low intensity ultraviolet radiation until a coatable syrup was prepared. Subsequently, 34 g of HDK HI 5 fumed silica was added, 2.2 g of HDDA, and 3.8 g 651 were added to the syrup and mixed with a Netzsch Model 50 Dispersator. Next 160 g of glass bubbles were added and mixed thoroughly by rolling over night and degassed.
  • the Adhesive Skin 1 composition and coatable syrup were coated sequentially between a release liner and a primed 3mil PET film such that the Adhesive Skin 1 was in contact with the release liner and the syrup was in contact with the PET film and cured by 998 mW/cm 2 UVA light.
  • the adhesive skin was coated at various thicknesses as indicated in the following table, while concurrently reducing the thickness of the coatable syrup such that the total thickness of the adhesive layers was 25 mils.
  • the cured samples were then tested for peel and shear as described in the following table.
  • Example 9 was tested for adhesive reusability. The results are as follows:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

L'invention concerne des articles revêtus adhésifs, comprenant un substrat comprenant une première surface principale et une seconde surface principale opposée et une couche adhésive autocollante disposée sur la première surface principale du substrat. Dans un mode de réalisation, la couche adhésive autocollante peut être retirée proprement du papier, est réutilisable et a un cisaillement avec une paroi sèche en peau d'orange avec un poids de 250 g d'au moins 500 minutes. La couche adhésive autocollante est de préférence un adhésif multicouche. Dans un autre mode de réalisation, l'invention concerne un article revêtu d'adhésif, comprenant un substrat comprenant une première surface principale et une seconde surface principale opposée et une couche adhésive autocollante disposée sur la première surface principale du substrat. L'adhésif autocollant multicouche comprend une première couche adhésive disposée sur la première surface principale du substrat et une seconde couche de peau adhésive autocollante disposée sur la première couche. Au moins la seconde couche de peau est un adhésif multicouche acrylique ne comprenant pas plus de 1 % en poids de motifs polymérisés dérivés de monomères fonctionnels acides. Dans certains modes de réalisation préférés, la première couche adhésive est conformable.
PCT/US2015/023330 2014-04-11 2015-03-30 Articles revêtus d'adhésif autocollant appropriés pour le collage à des surfaces rugueuses WO2015157019A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9914848B1 (en) 2016-10-31 2018-03-13 Ppg Architectural Finishes, Inc. Refinish coating composition
WO2024079569A1 (fr) * 2022-10-13 2024-04-18 3M Innovative Properties Company Copolymère stabilisant, composition adhésive, procédé de fabrication de celle-ci et article la comprenant

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005110737A1 (fr) * 2004-04-14 2005-11-24 Avery Dennison Corporation Rubans autoadhesifs durcis par faisceau electronique contenant des microspheres, et procedes de fabrication et d'utilisation des rubans autoadhesifs
US20110033699A1 (en) * 2009-07-23 2011-02-10 Nitto Denko Corporation Pressure-sensitive adhesive tape
WO2014172185A1 (fr) * 2013-04-15 2014-10-23 3M Innovative Properties Company Adhésifs comprenant un agent de réticulation comportant un groupe (méth)acrylate et un groupe oléfinique, et procédés

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005110737A1 (fr) * 2004-04-14 2005-11-24 Avery Dennison Corporation Rubans autoadhesifs durcis par faisceau electronique contenant des microspheres, et procedes de fabrication et d'utilisation des rubans autoadhesifs
US20110033699A1 (en) * 2009-07-23 2011-02-10 Nitto Denko Corporation Pressure-sensitive adhesive tape
WO2014172185A1 (fr) * 2013-04-15 2014-10-23 3M Innovative Properties Company Adhésifs comprenant un agent de réticulation comportant un groupe (méth)acrylate et un groupe oléfinique, et procédés

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9914848B1 (en) 2016-10-31 2018-03-13 Ppg Architectural Finishes, Inc. Refinish coating composition
US10358573B2 (en) 2016-10-31 2019-07-23 Ppg Architectural Finishes, Inc. Refinish coating composition
WO2024079569A1 (fr) * 2022-10-13 2024-04-18 3M Innovative Properties Company Copolymère stabilisant, composition adhésive, procédé de fabrication de celle-ci et article la comprenant

Also Published As

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